CN111555301B

CN111555301B - Intelligent active filter and reactive power phase shifter

Info

Publication number: CN111555301B
Application number: CN202010452281.XA
Authority: CN
Inventors: 李树广; 李珺磊
Original assignee: Shanghai Guang Ji Electric Co ltd
Current assignee: Shanghai Guang Ji Electric Co ltd
Priority date: 2020-05-26
Filing date: 2020-05-26
Publication date: 2021-11-09
Anticipated expiration: 2040-05-26
Also published as: CN111555301A

Abstract

The invention provides a reactive power phase shifter, which comprises a reactive power detection module, a reactive power phase shifting module and a reactive power electricity storage pi-shaped delayer which are connected with each other, wherein: the reactive power detection module is used for detecting the reactive power of the power grid and sending the detected reactive power to the reactive power pi-type delayer for power storage; and the reactive power phase shifting module is used for shifting the phase of the reactive power of the power grid stored in the reactive power pi-type delayer into active power to be transmitted to the power grid. Meanwhile, an intelligent active filter based on the reactive power phase shifter is provided. According to the intelligent active filter and the reactive power phase shifter, the reactive power and the harmonic waves of the power grid are converted into the active power, the high-speed high-precision compensation is performed on the power grid interference and fluctuation impact power, the power grid interference and fluctuation are eliminated, the energy is saved, the emission is reduced, and the quality and the safety of the power grid are improved.

Description

Intelligent active filter and reactive power phase shifter

Technical Field

The invention relates to a power grid active filter in the technical field of power electronic control, in particular to an intelligent compensation energy-saving device for a power grid and a power system, namely an intelligent active filter and a reactive power phase shifter.

Background

With the development of the world energy crisis, the invention of new energy is an important proposition in the world science field, and meanwhile, the saving of the existing energy is an important research topic at present in the scientific community. The new energy needs to be provided for a day, and the existing energy conservation is urgent in the world at present. The current field of the tramcar and the metal smelting is that the world has the largest power consumption and the heaviest environmental pollution, and a large amount of generated higher harmonics and reactive power cause great interference and harm to a power grid, thereby seriously influencing the safety and the power supply quality of the power grid.

At present, the most adopted metal smelting systems of electric railways, steel, iron, aluminum and the like are an LC filter, SVC and SVG, the compensation precision is low, resonance is easy to generate, the size is large, the power consumption is large, and the requirements of a power grid and a power system cannot be met.

Through the literature search of the prior art, application No. 201220183143 discloses a power active filter, which includes: and controlling the compensation circuit to perform reverse compensation on the harmonic current component according to the analysis result of the actually measured load current waveform. However, this method has low compensation accuracy, low withstand voltage, small capacity, and poor reliability.

It is found that the utility model with application number 201020254744 provides a hybrid active filter, including the active filter and the passive filter of establishing ties, but can not bear the fundamental voltage of electric wire netting alternating current power supply, and the device capacity is little, and the compensation precision is low, and is withstand voltage low, fragile, can not be suitable for high voltage large capacity power system in the retrieval.

The chinese patent CN201310492608.6 applied by the present applicant discloses an energy-saving device for higher harmonic and reactive power compensation of an active power grid, which mainly aims at the higher harmonic and reactive power generated by the common characteristics of the common load of the power grid to perform the energy-saving device for power grid harmonic and reactive power compensation.

At present, no explanation or report of the similar technology of the invention is found, and similar data at home and abroad are not collected.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides an intelligent active filter and a reactive power phase shifter.

The invention is realized by the following technical scheme.

According to an aspect of the present invention, there is provided a reactive power phase shifter comprising a reactive power detection module, a reactive power phase shifting module, and a reactive power pi-type delayer connected to each other, wherein:

the reactive power detection module is used for detecting the reactive power of the power grid and sending the detected reactive power to the reactive power pi-type delayer for power storage;

and the reactive power phase shifting module is used for shifting the phase of the reactive power of the power grid stored in the reactive power pi-type delayer into active power to be transmitted to the power grid.

Preferably, the reactive power detection module comprises a JK trigger, a reactive power detection controller and a first high-voltage field effect transistor module; the Q output end of the JK trigger is connected with the control end of the reactive power detection controller to control the starting of the reactive power detection controller; and the signal input end of the reactive power detection controller controls the first high-voltage field effect transistor module to detect the reactive power of the power grid and send the detected reactive power to the reactive power pi-type delayer for power storage.

Preferably, the JK trigger controls the reactive power detection controller to be turned on according to an initial phase of the reactive current input from the J control terminal; the JK trigger controls the reactive power detection controller to convert the instantaneous value signals of the reactive power input by the signal input end into analog control signals of the first high-voltage field effect transistor module, and the first high-voltage field effect transistor module is controlled.

Preferably, the reactive power phase shift module comprises a second high-voltage field effect transistor module and a reactive power phase shift controller; q of the JK flip-flop^-The output end is connected with the control end of the reactive power phase shifting controller to control the starting of the reactive power phase shifting controller; and the signal input end of the reactive power phase-shifting controller controls the second high-voltage field effect transistor module to phase-shift the reactive power of the power grid stored in the reactive power pi-type delayer into active power to be sent to the power grid.

Preferably, the JK trigger controls the reactive power phase shift controller to be turned on according to the final phase of the reactive power input from the K control terminal; and the reactive power phase-shifting controller converts the instantaneous value sequence signals of each reactive power input by the signal input end into analog sequence control voltage signals of the second high-voltage field effect transistor module to control the second high-voltage field effect transistor module.

According to another aspect of the present invention, there is provided a smart active filter including: any one of the reactive power phase shifter, the isolating switch, the grid-connected inductance-adjusting transformer, the power grid detection device, the A/D converter, the harmonic/active converter, the power grid compensation device, the inductance adjustment controller, the system protection controller and the DSP-FFT intelligent controller; wherein:

the power grid detection device is used for detecting the voltage current and the operation state of a power grid and a load system, converting the voltage current and the operation state signal of the power grid into a low-voltage analog signal and inputting the low-voltage analog signal into the A/D converter;

the A/D converter is used for converting the low-voltage analog signal output by the power grid detection device into a digital signal and inputting the digital signal into the DSP-FFT controller;

the DSP-FFT controller is used for detecting, analyzing and monitoring the voltage and current and the running state of the power grid and the load system, calculating the frequency, the phase and the amplitude of the reactive power and each subharmonic of the power grid according to the output signal of the A/D converter, and calculating the control instructions and parameters of a reactive power phase shifter, a harmonic/active converter, a power grid compensation device, an inductance regulation controller and a system protection controller, and is characterized in that:

the DSP-FFT controller controls the reactive power phase shifter to shift the reactive power generated by the power grid and the load system into active power through the control instruction, and the active power is returned to the power grid through the grid-connected inductive transformer, so that a large amount of power and electric energy are saved;

the DSP-FFT controller controls the harmonic/active converter through the control instruction to convert the harmonic generated by the power grid and the load system into active power, and the active power is returned to the power grid through the grid-connected inductive transformer, so that a large amount of power and electric energy is saved;

the DSP-FFT controller controls the power grid compensation device to compensate power grid harmonic wave and reactive power, interference and fluctuation impact power through instructions, power grid interference and fluctuation are eliminated, and power grid quality and safety are improved;

the DSP-FFT controller controls the inductance adjusting controller to adjust and control the current of the grid-connected inductance transformer through the instruction so as to adjust the inductance value of the grid-connected inductance transformer, so that the grid-connected inductance transformer forms a resonance detection device, and further, each subharmonic of the power grid flows into the harmonic/active converter to be converted into active power, and the active power is returned to the power grid by the grid-connected inductance transformer;

the DSP-FFT controller controls the system protection controller through an instruction, and drives the isolating switch to be disconnected when the power grid or the load system is abnormal or fails, so that the connection between the fault equipment and the power grid is cut off.

Preferably, the DSP-FFT intelligent controller comprises: DSP signal processor, DSP-FFT analysis processor, DSP control instruction arithmetic unit and DSP system protection instruction arithmetic unit, wherein:

the DSP is used for detecting, monitoring, data processing and displaying the power grid and the load system;

the DSP-FFT analysis processor is used for calculating the frequency amplitude and the phase of the voltage current, each harmonic wave and reactive power, and the interference and fluctuation power of the power grid and the load system;

the DSP control instruction arithmetic unit is used for calculating control instruction parameters of the reactive power phase shifter, the harmonic/active conversion device, the power grid compensation device, the inductance regulation controller and the system protection controller, controlling the grid-connected inductance transformer and sending active power generated by the reactive power phase shifter and the harmonic/active conversion device and compensation voltage current generated by the power grid compensation device into a power grid;

and the DSP system protection instruction arithmetic unit calculates the control instruction and parameters of the system protection controller according to the voltage and current and the running state signals of the power grid and the load system output by the A/D converter, the power grid protection operation rules, the driving structure characteristics of the isolating switch and the set tolerance values of overvoltage, overcurrent and overtemperature of each power device.

Preferably, the DSP-FFT controller calculates the frequency, phase and amplitude of the grid reactive power and each subharmonic, i.e. the initial phase of the reactive power in the reactive power region in each period of the grid power waveform, and the instantaneous value and the final phase of each reactive power by the DSP-FFT analysis processor, controls the reactive power phase shifter, shifts the phase of the reactive power generated by the grid and the load system to the active power having the same phase as the grid voltage, and returns the active power to the grid through the grid-connected inductance transformer.

Preferably, the DSP-FFT controller calculates the voltage and current of the grid and the load system and the frequency phase and amplitude of each harmonic power by the DSP-FFT analysis processor, controls the harmonic/active converter, converts the grid harmonic into active power, and returns the active power to the grid through the grid-connected inductance transformer.

Preferably, the DSP-FFT controller calculates and predicts a harmonic, reactive power and interference fluctuation impact power variation law of the power grid from the output signal of the a/D converter, controls the power grid compensation device to generate a suppression control signal and a power grid compensation voltage current for the harmonic, reactive power and interference fluctuation power of the power grid, and sends the suppression control signal and the power grid compensation voltage current to the power grid through the grid-connected inductance transformer, so as to perform suppression control and compensation for the harmonic, reactive power and interference fluctuation power of the power grid.

Preferably, the grid-connected inductance transformer includes: tuning inductance winding, inductance regulation and control winding, reactive phase-shift electric energy return winding, harmonic/active conversion electric energy return winding, electric network compensation winding, transformation grid-connected winding and high-voltage capacitor C, wherein: the inductance regulating and controlling winding is controlled by an inductance regulating controller, and the inductance value of the tuning inductance winding is regulated and controlled, so that the inductance value of the tuning inductance winding is connected with the high-voltage capacitor C to form an adjustable LC resonance circuit, and further, all subharmonics flow into the harmonic/active converter; then the DSP-FFT controller controls a harmonic/active converter to convert the harmonic of the power grid into active power with the same frequency and the same phase as the voltage of the power grid, and the active power is returned to the power grid through a harmonic/active conversion electric energy return winding and a voltage transformation grid-connected winding;

the DSP-FFT controller controls a reactive power phase shifter to shift the reactive power of the power grid into active power, and the active power is returned to the power grid through a reactive phase-shifting power return winding and a voltage transformation grid-connected winding;

and the DSP-FFT controller controls the power grid compensation voltage and current output by the power grid compensation device to be sent to the power grid compensation winding (2-5), and the power grid compensation winding and the transformation grid-connected winding are used for boosting and sending the power grid compensation voltage and current to a power grid.

Preferably, the grid detection device includes: the detection device and the signal conversion sensor for detecting the power grid and the load system respectively convert voltage, current and running state signals of the power grid and the load system into low-voltage analog signals to be input into the A/D converter, and the low-voltage analog signals are converted into digital signals by the A/D converter to be input into the DSP-FFT intelligent controller.

Preferably, the DSP-FFT controller detects and monitors the power grid and the load system in real time through the power grid detection device, when the power grid or the load system is abnormal and has faults, the DSP-FFT controller controls the system protection controller and the isolating switch to switch off the intelligent active filter from the power grid, and simultaneously sends out a notification alarm signal through the communication alarm device; when the power grid or the load system is recovered to be normal, a normal notification signal is sent out through the communication alarm device, and the DSP-FFT controller controls the system protection controller to be switched on and connected with the isolating switch.

Compared with the prior art, the invention has the following beneficial effects:

the intelligent active filter and the reactive power phase shifter thereof provided by the invention are used for controlling the reactive power phase shifter and the harmonic/reactive converter to convert power grid harmonic waves and reactive power into active power and return the active power to a power grid aiming at higher harmonic waves and reactive power generated by metal smelting systems such as national power grids, electric trains, railways, steel, iron, aluminum and the like by utilizing the high-speed DSP-FFT intelligent controller, have a huge energy-saving effect, simultaneously perform high-speed high-precision compensation and inhibition on power grid harmonic waves, reactive power and power grid interference fluctuation power, eliminate power grid interference and fluctuation, save energy, reduce emission, improve power grid power factor and power grid quality, improve stability, reliability and safety of the power grid and a production load system, improve product quality, reduce production cost and have huge economic benefit and social benefit.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

fig. 1 is a schematic block diagram of an intelligent active filter system according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a structure and a control system of a grid-connected inductor transformer in an intelligent active filter according to an embodiment of the present invention;

fig. 3 is a schematic diagram illustrating the function and structure of a reactive power phase shifter and a harmonic/active converter in an intelligent active filter according to an embodiment of the present invention;

fig. 4 is a schematic diagram illustrating a reactive power detection and reactive power phase shifter control principle of a power grid in an intelligent active filter according to an embodiment of the present invention;

fig. 5 is a block diagram of a reactive power phase shifter according to an embodiment of the present invention;

fig. 6 is a graph of grid voltage current versus reactive power waveforms.

Detailed Description

The following examples illustrate the invention in detail: the embodiment is implemented on the premise of the technical scheme of the invention, and a detailed implementation mode and a specific operation process are given. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.

An embodiment of the present invention provides a Reactive Power Phase Shifter (RPPS) according to characteristics of a power grid harmonic and Reactive power, as shown in fig. 3 to 5, including: reactive power detection module, reactive power phase shift module and reactive power pi type delayer 5-2 of interconnect, wherein:

the reactive power detection module is used for detecting the reactive power of the power grid and sending the detected reactive power to the reactive power pi-type delayer 5-2 for power storage;

and the reactive power phase-shifting module is used for phase-shifting the reactive power of the power grid stored in the reactive power pi-type delayer 5-2 into active power to be sent to the power grid.

As a preferred embodiment, the reactive power detection module 5-1-1 comprises a JK trigger 5-3, a reactive power detection controller 5-4-1 and a first high-voltage field effect transistor module; the Q output end of the JK trigger 5-3 is connected with the control end of the reactive power detection controller 5-4-1 to control the starting of the reactive power detection controller 5-4-1; and the signal input end of the reactive power detection controller 5-4-1 controls the first high-voltage field effect transistor module to detect the reactive power of the power grid and send the detected reactive power to the reactive power pi-type delayer 5-2 for power storage.

As a preferred embodiment, the JK trigger 5-3 controls the reactive power detection controller 5-4-1 to be started according to the initial phase of the reactive power input by the J control end; the JK trigger controls the reactive power detection controller 5-4-1 to convert the instantaneous value signals of each reactive power at the input signal end into analog control signals of the first high-voltage field effect transistor module, and the first high-voltage field effect transistor module is controlled.

As a preferred embodiment, the reactive power phase shift module 5-1-2 comprises a second high-voltage field effect transistor module and a reactive power phase shift controller 5-4-2; q of JK flip-flop 5-3^-Output terminal and reactive powerThe control end of the force phase shifting controller 5-4-2 is connected to control the starting of the reactive power phase shifting controller 5-4-2; and the signal input end of the reactive power phase-shifting controller 5-4-2 controls the second high-voltage field effect transistor module to phase-shift the reactive power of the power grid stored in the reactive power pi-type delayer 5-2 into active power to be sent to the power grid.

As a preferred embodiment, the JK trigger 5-3 controls the reactive power phase shift controller 5-4-2 to be started according to the tail phase of the reactive power input by the K control end; the reactive power phase-shifting controller 5-4-2 converts the instantaneous value sequence signals of each reactive power input by the signal input end into analog sequence control voltage signals of the second high-voltage field effect transistor module to control the second high-voltage field effect transistor module.

Fig. 3 to 5 show schematic diagrams of the structure and control of a reactive power phase shifter according to a specific application of the reactive power phase shifter; wherein:

in fig. 3, 5-1-1 is a reactive power detection module, 5-1-2 is a reactive power phase shift module, 5-2 is a reactive power pi-type delayer, 6-1 is a power grid harmonic rectifier, and 6-2 is a harmonic/active power converter. i.e. i_rThe current outside the voltage coverage is the reactive power (or called reactive current), i_hFor higher harmonic currents i_r+πTo handle reactive power i_rActive power i after phase shift by pi electric angle_a，i_WFor the phase-shifted network current i_nWIs the network current of each period, wherein n is 1, 2, 3.

In FIG. 4, 3-0 includes: a power grid current detection sensor/voltage signal converter, which is called a current signal detection converter for short, 3 is a power grid detection device, and 5-2 is a reactive power pi-type delayer, namely, a reactive power detection module 5-1-1 sends reactive power detection in an area R shown in figure 6 to the reactive power pi-type delayer 5-2; and then the reactive power phase shift module 5-1-2 is controlled by the power phase shift controller 5-4-2, and the power stored in the reactive power pi-type delayer 5-2 is subjected to phase shift by pi electrical angle (pi is 3.14 electrical angle) in a time delay way and is sent to the area A to be converted into active power. Wherein u is_iTo pass the grid current i through i/u_iConverter and operational amplifier K for converting to low voltage analog signal voltage u_iSending to an A/D converter; beta is a₁For the initial phase of the reactive current force, beta₂Is the end phase of the power i_rcIs a control command value, i, of the reactive power detection module_acThe control instruction value of the reactive power phase shifting module is i, i is the power grid current, and phi is the phase angle of the power grid current i leading or lagging the power grid voltage u, namely the power factor angle of the power factor COS phi.

In fig. 5, 5-1-1 and 5-1-2 are respectively a reactive power detection module formed by a reactive power detection P-MOS high voltage field effect transistor module (i.e., a first high voltage field effect transistor module) and a reactive power phase shift module formed by a reactive power phase shift control N-MOS high voltage field effect transistor module (i.e., a second high voltage field effect transistor module), 5-2 is a reactive power pi-type delayer, 5-3 is a phase shift control JK trigger (abbreviated as JK trigger), and 5-4-1 and 5-4-2 are respectively a reactive power detection controller and a reactive power phase shift controller.

Another embodiment of the present invention provides an Intelligent Active Filter (IAF), which converts the power grid harmonic and reactive power into Active power to be sent back to the power grid, thereby saving a large amount of power and power, and meanwhile, the power grid compensation device is controlled by a high-speed DSP to perform high-speed and high-precision compensation on the harmonic and reactive power generated by the power grid and the power grid interference fluctuation harmful power, thereby eliminating the power grid interference and fluctuation.

As shown in fig. 1, the smart active filter includes: the system comprises a reactive power phase shifter 5, an isolating switch 1, a grid-connected inductance-adjusting transformer 2, a power grid detection device 3, an A/D converter 4, a harmonic/active converter 6, a power grid compensation device 7, an inductance adjustment controller 8, a system protection controller 9 and a DSP-FFT intelligent controller 10; wherein:

As a preferred embodiment, the DSP-FFT intelligent controller comprises: DSP signal processor, DSP-FFT analysis processor, DSP control instruction arithmetic unit and DSP system protection instruction arithmetic unit, wherein:

In a preferred embodiment, the DSP-FFT controller calculates the frequency, phase and amplitude of the grid reactive power and each subharmonic, i.e. the initial phase of the reactive power in the reactive power region in each period of the grid power waveform, and the instantaneous value and final phase of each reactive power, by the DSP-FFT analysis processor, controls the reactive power phase shifter, shifts the phase of the reactive power generated by the grid and the load system to the active power having the same phase as the grid voltage, and returns the active power to the grid through the grid-connected inductance transformer.

In a preferred embodiment, the DSP-FFT controller calculates the voltage and current of the grid and the load system and the frequency phase and amplitude of each harmonic power by the DSP-FFT analysis processor, controls the harmonic/active converter, converts the grid harmonic into active power, and returns the active power to the grid through the grid-connected inductance transformer.

As a preferred embodiment, the DSP-FFT controller calculates and predicts the change rule of the harmonic, reactive power and interference fluctuation impact power of the power grid according to the output signal of the a/D converter, controls the power grid compensation device to generate a suppression control signal and a power grid compensation voltage current for the harmonic, reactive power and interference fluctuation power of the power grid, and sends the suppression control signal and the power grid compensation voltage current to the power grid through the grid-connected inductance transformer, thereby performing suppression control and compensation for the harmonic, reactive power and interference fluctuation power of the power grid.

As a preferred embodiment, the grid-connected inductance transformer includes: tuning inductance winding, inductance regulation and control winding, reactive phase-shift electric energy return winding, harmonic/active conversion electric energy return winding, electric network compensation winding, transformation grid-connected winding and high-voltage capacitor C, wherein: the inductance regulating and controlling winding is controlled by an inductance regulating controller, and the inductance value of the tuning inductance winding is regulated and controlled, so that the inductance value of the tuning inductance winding is connected with the high-voltage capacitor C to form an adjustable LC resonance circuit, and further, all subharmonics flow into the harmonic/active converter; then the DSP-FFT controller controls a harmonic/active converter to convert the harmonic of the power grid into active power with the same frequency and the same phase as the voltage of the power grid, and the active power is returned to the power grid through a harmonic/active conversion electric energy return winding and a voltage transformation grid-connected winding;

As a preferred embodiment, the grid detection apparatus includes: the detection device and the signal conversion sensor for detecting the power grid and the load system respectively convert voltage, current and running state signals of the power grid and the load system into low-voltage analog signals to be input into the A/D converter, and the low-voltage analog signals are converted into digital signals by the A/D converter to be input into the DSP-FFT intelligent controller.

As a preferred embodiment, the DSP-FFT controller detects and monitors the power grid and the load system in real time through the power grid detection device, when the power grid or the load system is abnormal and has faults, the DSP-FFT controller controls the system protection controller and the isolating switch, the intelligent active filter is switched off from the power grid, and meanwhile, the communication alarm device sends out an alarm signal; when the power grid or the load system is recovered to be normal, a normal notification signal is sent out through the communication alarm device, and the DSP-FFT controller controls the system protection controller to be switched on and connected with the isolating switch.

The working principle of the intelligent active filter and the reactive power phase shifter provided by the embodiment of the invention is as follows:

the power grid detection device detects the voltage and current of a power grid and a power grid running state signal, the output end of the power grid detection device is connected with the input end of an A/D converter, the A/D converter converts the signals into digital signals and sends the digital signals to a DSP-FFT intelligent controller, the DSP-FFT intelligent controller calculates and analyzes the frequency, the phase and the amplitude of reactive power and each subharmonic of the power grid, and calculates control instructions and parameters of each controller; that is, as shown in fig. 6, the initial phase β of the reactive power in the reactive power R region in each cycle of the grid power waveform is detected and calculated_1-1Instantaneous value i of each reactive power_r-nAnd end phase beta_2-1And the control instruction values of the reactive power detection controller and the reactive power phase shift controller; as shown in figure 5, the output of the DSP-FFT intelligent controller is connected with a JK trigger, the Q output end of the JK trigger is connected with the control end of the reactive power detection controller, and Q^-The output end is connected with the control end of the reactive power phase-shifting controller; initial phase beta of reactive power is converted by a DSP-FFT intelligent controller_1-1Sending the J control end of the JK trigger to make the Q of the JK trigger output high potential '1', Q^-Outputting a low potential of 0 to open the reactive power detection controller and close the reactive power phase-shifting controller; meanwhile, the DSP-FFT intelligent controller converts the instantaneous value i of the reactive power_r-nSampling, calculating and storing instantaneous value i_r-nI of power transmission reactive power detection controller_rc/u_rcA signal input terminal for receiving the signal from the reactive power detection controller_r-nSignal conversion to analog control signal u of first high voltage fet module_rcFrom u_rcAnd controlling the first high-voltage field effect transistor module to detect the reactive power of the power grid and send the detected reactive power to a reactive power storage pi-shaped delayer (5-2) for power storage.

When the DSP-FFT intelligent controller detects the reactive power end phase beta_2-1SignalThen, the DSP-FFT intelligent controller controls the beta_2-1The signal is sent to the K control end of the JK trigger to make the JK trigger reverse, the Q outputs a low potential ' 0 ', and the Q outputs a low potential ' 0^-Outputting high potential '1' to close the reactive power detection controller and open the reactive power phase shift controller; meanwhile, the DSP-FFT intelligent controller sends the instantaneous value i of the reactive power_r-nSequence signals sent to the power phase shift controller in time sequence i_ac/u_acA signal input terminal for inputting the instantaneous value i by the power phase shift controller_r-nConverting the sequence signal into an analog sequence control voltage signal u of a second high-voltage field effect transistor module_acFrom u_acControlling the second high voltage FET module to phase-shift the reactive power stored in the reactive power pi-type delayer into the A region beta shown in FIG. 6 according to the stored sequence_2-1～β_1-2In the active power interval, the second high-voltage field effect transistor module controls the reactive phase-shifting electric energy sent to the inductive transformer to return to the winding, and the reactive phase-shifting electric energy is sent to the power grid through the transformation grid-connected winding.

The DSP-FFT intelligent controller controls the power grid detection device and the A/D converter to detect voltage current and reactive power of a power grid and a load system; the reactive power phase-shifting controller controls the first high-voltage field effect transistor module to detect the reactive power of the power grid and send the detected reactive power to the reactive power pi-type delayer for power storage, and the reactive power phase-shifting controller controls the second high-voltage field effect transistor module to shift the phase of the power stored by the reactive power pi-type delayer into active power and send the active power to the power grid.

The intelligent active filter and the reactive power phase shifter provided by the embodiment of the invention convert reactive power and harmonic waves generated by a power grid, a trolley bus railway, a metal smelting system and the like into active power and return the active power to the power grid, save a large amount of power and electric energy, and simultaneously carry out high-speed high-precision compensation on the reactive power, the harmonic waves and interference fluctuation harmful power of the power grid, eliminate the interference and fluctuation of the power grid, improve the stability and safety of the power grid, save energy, reduce emission, improve the quality of the power grid, reduce the loss of electrical equipment and prolong the service life of the equipment.

The technical solutions provided by the embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

In fig. 1, 1 is a high-voltage isolating switch, 2 is a grid-connected inductance transformer, 3 is a power grid detection device (including a detection device 3-1 for detecting a power grid and a load system, 3-2 signal conversion sensors, 4 are a/D converters, 5 is a reactive power phase shifter, 6 is a harmonic/active converter, 7 is a power grid compensation device, 8 is an inductance adjustment controller, 9 is a system protection controller, 10 is a DSP-FFT intelligent controller (including a DSP signal processor 10-1, a DSP-FFT analysis processor 10-2, a DSP control instruction arithmetic unit 10-3, a DSP system protection instruction arithmetic unit 10-4), and 11 is a communication alarm device.

In fig. 2, 2-1 is a tuning inductance winding, 2-2 is an inductance regulating winding, 2-3 is a reactive phase-shifting power return winding, 2-4 is a harmonic/active power conversion power return winding, 2-5 is a power grid compensation winding, 2-6 is a transformation grid-connected winding, and a connection control structure diagram with each controller. i.e. i_rThe current outside the voltage coverage is the reactive power (or called reactive current), i_rhFor higher harmonics and reactive power i_hAre higher harmonics.

In FIG. 6, u is the grid voltage, i is the grid current, i_aThe area covered by the voltage u and the current i together is an active power W area, phi is the phase angle of the current i leading or lagging the voltage u, the area of the current i lagging the voltage u is called a reactive power R area, namely, the current outside the voltage coverage is the reactive power i_rOr called as a reactive power region, the reactive power region is marked as an R region by oblique lines; the function of the reactive power phase shifter in the patent is to shift the reactive power in the R area to the voltage coverage area, namely the A area shown in figure 6, so that the phase-shifted power grid current i_WIn phase with the voltage, phi → 0, power factor COS phi → 1; the residual reactive current voltage and harmonic after phase shifting are compensated by the power grid compensation device shown in fig. 1.

According to the intelligent active filter provided by the embodiment of the invention, the reactive power phase shifter 5 comprises a reactive power detection module 5-1-1, a reactive power phase shifting module 5-1-2 and a reactive power pi-type delayer 5-2; the harmonic/active converter 6 consists of a harmonic electric detection rectifier 6-1 and an active electric PWM inverter 6-2; network via reactive powerThe residual reactive power i after the phase shifter 5 and the harmonic/active converter 6 are processed_reAnd harmonic voltage u_heReactive compensation power-i generated by the network compensation device 7_reHarmonic compensation voltage-u of_heAnd performing high-speed high-precision compensation. The power grid compensation device 7 controls each PWM inverter to generate reactive compensation power-i by the DSP_reCompensating voltage-u with each harmonic of power grid_he。

The network voltage u and current i signals are sent to a network detection device 3 to be converted into low-voltage analog signals, then sent to an A/D converter 4 to be converted into digital signals, sent to a DSP-FFT controller, the phase, the amplitude and the phase difference phi of the network voltage u and the current i are calculated, and the reactive power i of the network is calculated_rAnd each moment reactive power instantaneous value i_rnThen converting the grid current i into a voltage u_iSignal, calculating u-u_i＝u_r，u_rPhase angle at time 0 is beta_1-1、β_2-1、β_1-2、β_2-2、···、β_1-n、β_2-n(ii) a Function of reactive power phase shifter in beta_1-1～β_2-1Within time, from the instantaneous value i of reactive power_rn(or (i)_rnConversion to instantaneous voltage control signal u_rn) Controlling the high voltage field effect transistor module to be conducted to enable the reactive power i in the R region shown in figure 6_rThe detection is transmitted to a reactive power pi-type delayer 5-2; at beta_2-1～β_1-2Within the time, the reactive power instantaneous value i_rn(or u)_rn) And controlling the conduction of the high-voltage field effect transistor module, transferring the reactive power stored in the reactive power pi-type delayer 5-2 into the area A shown in the figure 6 to be converted into active power, and then sending the active power into the power grid through the grid-connected inductance transformer 2, so that phi → 0 and the power factor COS phi → 1 are realized, and the phase of the current i of the power grid is in the same phase as the voltage u. Therefore, the reactive power in the R zone is shifted to the A zone to be converted into active power.

The amplitude u of the voltage and current of each higher harmonic wave of the power grid calculated by the DSP-FFT controller_HnAnd i_HnPhase phi_HnAnd frequency omega_HnCalculating control commands and parameters of the harmonic/active converter 6 to control the harmonic/active transformerThe converter 6 rectifies and converts the harmonic wave of the power grid into active power, and the active power is returned to the power grid by the grid-connected inductive transformer 2; the transformed power grid residual interference fluctuation harmful power is subjected to high-speed high-precision compensation by the power grid compensation device 7.

As shown in fig. 1, the smart active filter includes: the system comprises an isolating switch 1, a grid-connected inductance transformer 2, a power grid detection device 3, an A/D converter 4, a reactive power phase shifter 5, a harmonic/active converter 6, a power grid compensation device 7, an inductance tuning controller 8, a system protection controller 9, a DSP-FFT controller 10 and a communication alarm device 11; wherein the PWM inverter is part of the harmonic/active converter 6 and the grid compensation device 7.

The power grid detection device 3 is used for detecting the voltage current and the operation state of a power grid and a load system, converting the voltage current of the power grid into a low-voltage analog signal, inputting the low-voltage analog signal into the A/D converter 4, converting the low-voltage analog signal into a digital signal and sending the digital signal to the DSP-FFT intelligent controller 10;

the DSP-FFT intelligent controller 10 functions as shown in fig. 1 and 4, calculates and analyzes the voltage and current of the grid and the load and the operation state, according to the voltage and current signals of the power grid and the load output by the power grid detection device 3, the frequency, the phase and the amplitude of reactive power and each subharmonic of the power grid are calculated, the control commands of the reactive power phase shifter 5, the harmonic/active converter 6, the power grid compensation device 7, the inductance regulation controller 8 and the system protection controller 9 are calculated, the inductance regulation control winding 2-2 of the grid-connected inductance transformer 2 is controlled, the tuned inductance winding 2-1 is enabled to work in the optimal resonance state all the time, the impedance of each subharmonic and the reactive power detection circuit of the power grid is enabled to be zero, and the reactive power and the harmonic generated by the power grid and the load are input into the reactive power phase shifter 5 and the harmonic/active converter 6 to be converted into active power to be sent back to the power grid.

As shown in fig. 4, the DSP-FFT controller 10 controls the reactive power phase shifter 5 to shift the reactive power generated by the grid and the load to active power through the control instruction, and the grid-connected inductive transformer 2 returns the active power to the grid, so as to save a large amount of power and energy;

the DSP-FFT controller 10 controls the inductance adjusting controller 8 through a control instruction, adjusts 2-2 winding current of the grid-connected inductance transformer, controls 2-1 winding inductance value to work in the optimal resonance state all the time, enables impedance of each LC resonance branch circuit to be zero, inputs each subharmonic detection of the power grid into a rectifier of the harmonic/active power converter 6, controls the harmonic/active power converter 6 through the control instruction by the DSP-FFT controller 10 to convert the subharmonic/active power into active power with the same frequency and the same phase as the voltage of the power grid, and returns the power grid through the grid-connected inductance transformer 2, so that a large amount of power electric energy is saved;

the DSP-FFT controller 10 controls the power grid compensation device 7 to perform high-speed and high-precision compensation on the reactive power, the harmonic waves and the interference fluctuation power of the power grid through instructions, so that energy conservation and emission reduction are realized, power grid interference and impact are eliminated, the power grid quality is improved, and the power grid stability and safety are improved;

the DSP-FFT controller 10 controls the system protection controller 9 through an instruction, drives an isolating switch of the system protection controller when the power grid or a load system or a compensation device is abnormal or has a fault, cuts off the connection between the fault equipment and the power grid, protects the normal operation of the power grid and the non-fault equipment, and controls the communication alarm device 11 to send out an alarm signal and inform relevant departments.

In some embodiments, the system of the present invention is provided with a communication alarm device 11, which is also used for monitoring and telemetering monitoring of a power grid system, remote operation control system and information communication devices of related departments.

In an embodiment, the DSP-FFT intelligent controller 10 comprises: DSP signal processor 10-1, DSP-FFT analysis processor 10-2, DSP control instruction arithmetic unit 10-3 and DSP system protection instruction arithmetic unit 10-4, wherein:

the DSP signal processor 10-1 detects, monitors, analyzes and displays the running states of the power grid and the load system;

the DSP-FFT analysis processor 10-2 calculates the frequency, amplitude and phase of the voltage current, reactive power and each harmonic of the power grid and the load system;

the DSP control instruction arithmetic unit 10-3 calculates the control instruction and parameters of each controller; controlling a reactive power phase shifter 5, a harmonic/active converter 6 and an inductance tuning controller 8 through control instructions to convert the reactive power and the harmonic of the power grid into active power; secondly, the power grid compensation device 7 is controlled to generate power grid compensation voltage current required by a power grid; thirdly, controlling a grid-connected inductance transformer 2 to send the active power and the power grid compensation voltage current into a power grid;

the DSP system protection instruction arithmetic unit 10-4 calculates the control instruction of the system protection controller 8 according to the voltage, current and operation state data of the power grid and the load detected by the power grid detection device 3 and the A/D converter 4, the structural characteristics and the power grid operation rules of the system protection controller 8, and aims to distinguish and classify the accident when the overvoltage, overcurrent, overtemperature, short circuit, open circuit, breakdown fault or abnormal accident occurs in the power grid, the load system or the device of the invention, and send a control instruction to the system protection controller 8 according to the power grid operation rules, or drive a high-voltage isolating switch, or adjust the load matching, or cut off the connection between the power grid and the load, or cut off the accident equipment, and simultaneously alarm and inform relevant departments by a communication alarm device.

The DSP control instruction arithmetic unit 10-3 is used for calculating control instruction parameters of the reactive power phase shifter 5, the harmonic/active converter 6, the power grid compensation device 7, the inductance adjustment controller 8 and the system protection controller 9; the DSP control instruction arithmetic unit 10-3 controls the grid-connected inductive transformer 2, and active power generated by the reactive power phase shifter 5 and the harmonic/active converter 6 and compensation voltage generated by the power grid compensation device 7 are transmitted to a power grid through the grid-connected inductive transformer 2;

the DSP control instruction arithmetic unit 10-3 calculates the voltage and current of the power grid and the frequency amplitude and phase of each subharmonic and reactive power according to the DSP-FFT analysis processor 10-2, calculates the control parameters and instructions of the power grid compensation device 7 by combining the characteristics of the power grid compensation device 7, generates the compensation voltage and current of each subharmonic and reactive power and interference fluctuation signals by the power grid compensation device 7, and then sends the compensation voltage and current to the power grid by the grid-connected inductive transformer 2.

In the embodiment of the invention, a DSP controller 10-1 is used for detecting, analyzing and displaying signals and running states of a power grid and a load system, a DSP-FFT processor 10-2 is used for calculating the frequency amplitude and the phase of voltage and current of the power grid and the load system and each subharmonic and reactive power, a DSP instruction arithmetic unit 10-3 is used for calculating control instructions and parameters of each controller, and a DSP protection instruction arithmetic unit 10-4 is used for calculating control instruction parameters of a system protection controller 8.

As shown in fig. 2, the grid-connected inductive transformer 2 is composed of a tuning inductive winding 2-1, an inductive regulation winding 2-2, a reactive phase-shifting power return winding 2-3, a resonance/active transformation power return winding 2-4, a grid compensation winding 2-5 and a transformation grid-connected winding 2-6;

the power grid compensation device 7 is composed of a harmonic rectifier and a plurality of groups of PWM inverters, each group of PWM inverters is controlled by the DSP to generate compensation voltage and current of each subharmonic and reactive power of the power grid and interference fluctuation signals, and then the compensation voltage and current are sent to the power grid by the grid-connected inductance transformer 2.

The digital signals of the voltage and current signals of the power grid converted by the A/D converter 4 are input into the DSP-FFT controller 10, the frequency, the amplitude and the phase of each harmonic and reactive power of the power grid are calculated, and the control instruction of each controller is calculated; the inductance regulating and controlling winding 2-2 is controlled by the inductance regulating and controlling controller 8, each secondary inductance parameter of the tuning inductance winding 2-1 is regulated and controlled by the inductance regulating and controlling winding 2-2, the tuning inductance winding 2-1 is connected with the high-voltage capacitor C to form an LC resonance circuit, each secondary resonance inductance L of the tuning inductance winding 2-1 of the grid-connected inductance transformer 2 is enabled to work in the best resonance state all the time, the impedance of each secondary harmonic branch is enabled to be zero, harmonic detection generated by a power grid and a load is enabled to be input into the harmonic/active converter 6, higher harmonics of the power grid are converted into active power, then the grid is fed back to the power grid by the grid-connected inductance transformer 2-4 winding and the transformation grid-connected winding 2-6, and a large amount of power and electric energy is saved. The compensation voltage and the compensation current output by the power grid compensation device 7 are boosted by the power grid compensation windings 2-5 and the transformation grid connection windings 2-6 of the grid connection inductance transformer 2 and then sent to the power grid.

The specific work of the grid-connected inductive transformer 2 includes:

1. the high-voltage tuning inductance winding 2-1 is connected with a high-voltage capacitor C to form an LC resonance circuit, so that the impedance of each group of resonance circuits for each harmonic of the power grid is zero, and each harmonic of the power grid is input into a harmonic/active converter 6 for detection to be converted into active power;

2. the inductance value of the tuning inductance winding 2-1 is adjusted and controlled by the inductance control winding 2-2, so that an LC resonance circuit formed by the tuning inductance winding 2-1 and the high-voltage capacitor C is adapted to various changes of a power grid and always works in a resonance state.

3. The reactive power phase shifter 5 shifts the reactive power of the power grid into active power, and the active power is converted into high-voltage active power through the reactive phase-shifting electric energy loopback winding 2-3 and the voltage transformation grid-connected winding 2-6 and sent to the power grid.

4. The harmonic/active converter 6 converts the harmonic of the power grid into active power, and the active power is converted into high-voltage active power through the electric energy loopback windings 2-4 and the transformation grid-connected windings 2-6 and is transmitted to the power grid.

5. The compensation voltage current generated by the power grid compensation device 7 is changed into high-voltage compensation voltage current by the power grid compensation windings 2-5 and the transformation grid-connected windings 2-6 and is sent to the power grid.

The isolating switch 1 is controlled by a DSP-system protection instruction arithmetic unit 10-4, and when the power grid or a load system or the device of the invention is abnormal, the high-voltage isolating switch 1 is instantly disconnected or fault equipment is cut off, so that the power grid is protected.

In the embodiment of the invention, the power grid detection device 3 comprises a power grid voltage detection device 3-1 and a current conversion sensor 3-2, which respectively convert the power grid voltage, current and operation state into low-voltage analog signals to be input into an A/D converter 4, and the low-voltage analog signals are converted into digital signals by the A/D converter 4 to be input into a DSP-FFT controller 10.

In the intelligent active filter provided by the above embodiment of the present invention, through the power grid detection device 3, when an accident or a fault such as overvoltage, overcurrent, excessive temperature, overload, short circuit or breakdown occurs in the power grid, the load system or the compensation device, the DSP-FFT controller 10 controls the system protection controller 9 according to the power grid operation rule, and disconnects the isolating switch 1, and simultaneously, the communication alarm device 11 sends an alarm signal to the relevant department and device. When the fault is removed or the overvoltage and overcurrent are recovered to the normal range, the DSP-FFT controller 10 controls the system protection controller 9 according to the recovery condition of the power grid and the operation rule, drives the isolating switch 1 to be switched on, and automatically performs grid-connected operation, and can also manually recover the switching-on and grid-connected operation of the isolating switch 1.

According to the intelligent active filter and the reactive power phase shifter thereof provided by the embodiment of the invention, the reactive power and harmonic waves generated by the power grid and the load system are converted into the active power to be returned to the power grid by utilizing an intelligent prediction control theory and a reactive power phase shift control theory, so that a large amount of electric energy is saved; the method can inhibit interference signals and fluctuation impact power generated by the power system, effectively inhibit impact of surge voltage and current of the power system on a power grid: the high-speed high-precision compensation is carried out on the harmonic wave, the reactive power and the interference fluctuation power of the power grid, the insulation strength of power equipment and the service life of the power equipment are improved, the stability and the safety of the power grid are improved, the quality of the power grid is improved, energy is saved, emission is reduced, and a large amount of power and electric energy are saved. The invention can be applied to high-energy-consumption enterprises such as tramways, metal smelting systems of steel, iron, aluminum and the like, chemical oil refineries and the like, power plants, transformer substations and national power grids.

The intelligent active filter and the reactive power phase shifter thereof provided by the embodiment of the invention have the advantages of reasonable system structure, stable operation performance, high compensation precision, high speed, high energy-saving efficiency and high output voltage, can be used for various power grids and transformer substations below 220KV, tramways, railways, various metal smelting systems and various factory enterprises, are convenient to assemble and maintain, and further overcome the defects in the prior art, and have the following characteristics:

1. the DSP controller 10-1 and the DSP-FFT controller 10-2 are used for controlling and calculating the frequency amplitude and the phase of each subharmonic and reactive power of the power grid, and the DSP control instruction arithmetic unit 10-3 is used for calculating the control instruction and the parameter of each controller;

2. the DSP-FFT controller 10 is used for controlling the reactive power phase shifter 5 to shift the reactive power of the power grid into active power, and the active power is returned to the power grid through the grid-connected inductive transformer 2, so that a large amount of power and electric energy are saved;

3. the inductance adjusting controller 8 and the harmonic/active converter 6 are controlled by the DSP-FFT controller 10, the harmonic of the power grid is converted into active power, and the active power is returned to the power grid by the grid-connected inductance transformer 2, so that a large amount of power and electric energy are saved;

4. the DSP-FFT controller 10 is used for controlling the power grid compensation device 7, high-speed and high-precision compensation is carried out on power grid harmonic waves, reactive power and interference fluctuation power, power grid interference and impact are eliminated, energy is saved, emission is reduced, a large amount of power and electric energy is saved, the stability and the safety of a power grid are improved, and the quality of the power grid is improved. Has great economic benefit and social benefit.

5. Meanwhile, the DSP-FFT controller 10 is used for detecting, monitoring and analyzing faults of the power grid and the load system, the system protection controller 9 is controlled, and the isolation switch is driven to be switched off for overvoltage, overcurrent, overload, overtemperature, short circuit, breakdown fault and abnormal operation accidents generated by the power grid and the load, so that the fault equipment is instantaneously disconnected, or the system load is adjusted according to an overload adjusting rule.

6. Compared with the existing various compensation devices and filters: the existing various LC filters, SVC and SVG have large impact on a power grid, are easy to generate resonance and damage, and have low compensation precision, large volume and large power consumption.

7. The dynamic characteristic is good, the compensation speed is high, the precision is high, a large amount of electric power is saved, and the stability and the safety of an electric power system are improved. The invention has high voltage resistance, large compensation capacity and small volume, is suitable for all power systems below 220KV, and has the volume which is only one fourth of the volumes of the LC filter, the SVC and the SVG under the same compensation capacity.

8. The method is suitable for electric trains, railways, various steel, iron and aluminum metal smelting systems, machining and power electrical systems, chemical plant oil refineries, power plants, transformer substations and national power grids, and has wide development and application prospects.

The intelligent active filter and the reactive power phase shifter provided by the above embodiments of the present invention control the power grid detection communication system, the reactive power phase shifter and the power grid compensation control system through the DSP-FFT intelligent controller, and adopt the high-speed intelligent prediction and adaptive control modes, thereby improving the power grid voltage and current power waveform detection and FFT processing analysis capabilities and speed, improving the high-speed phase shift conversion function of reactive power/active power and the high-speed and high-precision compensation capability of power grid harmonics, having a fast and highly intelligent decision-making capability in coping with various changes of the power grid system and various operation rules and control mode selections of the power grid and selection of fault processing modes, and increasing the DSP calculation processing speed and analysis function, and adding the DSP controller with multiple dedicated functions, so as to improve the intelligent decision-making capability and speed of the DSP-FFT intelligent controller, the performance of the intelligent active filter, the reactive power conversion function and the high self-adaptive capacity to the working condition environment of the power grid are improved.

According to the intelligent active filter and the reactive power phase shifter thereof provided by the embodiment of the invention, the reactive power detection controller controls the first high-voltage field effect transistor module to detect the reactive power of the power grid and send the detected reactive power to the reactive power pi-type delayer for power storage; after the reactive power pi-type delayer delays the pi electric angle, a reactive power phase shift controller controls a second high-voltage field effect transistor module to control the phase shift of the stored power into active power which is sent to a power grid; the method is used for realizing the function of phase-shifting reactive power into active power. The reactive power of the power grid is shifted into active power, the harmonic waves of the power grid are converted into the active power and returned to the power grid, a large amount of power and electric energy are saved, meanwhile, high-speed high-precision compensation is carried out on the power grid interference and fluctuation impact power, the power grid interference and fluctuation are eliminated, energy is saved, emission is reduced, the power factor of the power grid is improved, and the quality and safety of the power grid are improved. The intelligent active filter is composed of a power grid detection device, an A/D converter, a high-speed DSP-FFT intelligent controller, a reactive power phase shifter, a harmonic/active converter, a power grid compensation device, an inductance regulation controller, a system protection controller, a grid-connected inductance transformer and a high-voltage isolating switch. The power grid detection device is used for detecting power grid harmonic waves and reactive power, the DSP-FFT controller is used for calculating components of each harmonic wave and reactive power of the power grid and control instructions and parameters of each controller, the reactive power phase shifter is controlled to shift the phase of the reactive power of the power grid into active power, the harmonic/active converter is controlled to convert the power grid harmonic waves into the active power, and the grid harmonic/active converter is connected with the grid inductance regulating transformer and returns the active power to the power grid, so that a large amount of power and electric energy are saved; meanwhile, the DSP-FFT controller controls the power grid compensation device and the system protection device to perform high-speed and high-precision compensation on power grid interference and fluctuation impact power, so that the power grid interference and fluctuation are eliminated, energy is saved, emission is reduced, and the quality and safety of a power grid are improved. The invention is suitable for high-energy-consumption enterprises and national power grids of power plants, wind power plants, transformer substations, tramways, metal smelting systems, chemical oil refineries and the like.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.

Claims

1. A reactive power phase shifter, comprising a reactive power detection module, a reactive power phase shifting module and a reactive power pi-type delayer (5-2) which are connected with each other, wherein:

the reactive power detection module is used for detecting the reactive power of the power grid and sending the detected reactive power to a reactive power pi-type delayer (5-2) for power storage;

the reactive power phase shifting module is used for shifting the phase of the reactive power of the power grid stored in the reactive power pi-type delayer (5-2) into active power to be sent to the power grid;

the reactive power detection module (5-1-1) comprises a JK trigger (5-3), a reactive power detection controller (5-4-1) and a first high-voltage field effect transistor module; the Q output end of the JK trigger (5-3) is connected with the control end of the reactive power detection controller (5-4-1) to control the starting of the reactive power detection controller (5-4-1); the signal input end of the reactive power detection controller (5-4-1) controls the first high-voltage field effect transistor module to detect the reactive power of the power grid and send the detected reactive power to the reactive power pi-type delayer (5-2) for power storage;

the JK trigger (5-3) controls the reactive power detection controller (5-4-1) to be started according to the initial phase of the reactive power input by the J control end; the JK trigger controls a reactive power detection controller (5-4-1) to convert each instantaneous value signal of reactive power of input signals into an analog control signal of the first high-voltage field effect transistor module, and the first high-voltage field effect transistor module is controlled;

the reactive power phase-shifting module (5-1-2) comprises a second high-voltage field effect transistor module and a power phase-shifting controller (5-4-2); q of the JK flip-flop (5-3)^-The output end is connected with the control end of the power phase shift controller (5-4-2) to control the powerStarting a phase shift controller (5-4-2); the signal input end of the power phase-shifting controller (5-4-2) controls the second high-voltage field effect transistor module to phase-shift the reactive power of the power grid stored in the reactive power pi-type delayer (5-2) into active power to be sent to the power grid;

the JK trigger (5-3) controls the power phase shift controller (5-4-2) to be started according to the tail phase of the reactive power input by the K control end; and the power phase-shifting controller (5-4-2) converts the instantaneous value sequence signals of each reactive power of the input signals into analog sequence control voltage signals of the second high-voltage field effect transistor module to control the second high-voltage field effect transistor module.

2. A smart active filter, comprising: a reactive power phase shifter (5), an isolating switch (1), a grid-connected inductance-adjusting transformer (2), a grid detection device (3), an A/D converter (4), a harmonic/active converter (6), a grid compensation device (7), an inductance adjustment controller (8), a system protection controller (9) and a DSP-FFT intelligent controller (10) according to claim 1; wherein:

the power grid detection device (3) is used for detecting the voltage current and the operation state of a power grid and a load system, converting the voltage current and the operation state signal of the power grid into a low-voltage analog signal and inputting the low-voltage analog signal into the A/D converter (4);

an A/D converter (4) for converting the low-voltage analog signal output by the power grid detection device (3) into a digital signal and inputting the digital signal into the DSP-FFT intelligent controller (10);

the DSP-FFT intelligent controller (10) detects, analyzes and monitors the voltage and current and the running state of the power grid and a load system, calculates the frequency, the phase and the amplitude of the reactive power and each subharmonic of the power grid according to the output signal of the A/D converter (4), and calculates the control instructions and parameters of the reactive power phase shifter (5), the harmonic/active converter (6), the power grid compensation device (7), the inductance regulation controller (8) and the system protection controller (9), and:

the DSP-FFT intelligent controller (10) controls the reactive power phase shifter (5) to shift the reactive power generated by the power grid and the load system into active power through a control instruction, and the active power is returned to the power grid through the grid-connected inductive transformer (2), so that a large amount of power and electric energy are saved;

the DSP-FFT intelligent controller (10) controls the harmonic/active converter (6) through a control instruction to convert harmonic generated by a power grid and a load system into active power, and the active power is returned to the power grid through the grid-connected inductive transformer (2), so that a large amount of power and electric energy are saved;

the DSP-FFT intelligent controller (10) controls the power grid compensation device (7) to compensate power grid harmonic wave and reactive power, interference and fluctuation impact power through instructions, so that power grid interference and fluctuation are eliminated, and the quality and safety of a power grid are improved;

the DSP-FFT intelligent controller (10) controls the inductance adjusting controller (8) to adjust and control the current of the grid-connected inductance transformer (2) through an instruction so as to adjust the inductance value of the grid-connected inductance transformer (2), so that the grid-connected inductance transformer (2) forms a resonance detection device, and further, each subharmonic of the power grid flows into the harmonic/active converter (6) to be converted into active power, and the active power is returned to the power grid by the grid-connected inductance transformer (2);

the DSP-FFT intelligent controller (10) controls the system protection controller (9) through an instruction, and drives the isolating switch (1) to be disconnected when the power grid or the load system is abnormal or fails, so that the connection between the failed equipment and the power grid is cut off.

3. The intelligent active filter according to claim 2, characterized in that the DSP-FFT intelligent controller (10) comprises: DSP signal processor (10-1), DSP-FFT analysis processor (10-2), DSP control instruction arithmetic unit (10-3) and DSP system protection instruction arithmetic unit (10-4), wherein:

the DSP signal processor (10-1) is used for detecting, monitoring, data processing and displaying a power grid and a load system;

the DSP-FFT analysis processor (10-2) is used for calculating the frequency amplitude and the phase of the voltage current, each harmonic wave and reactive power, and the interference and fluctuation power of the power grid and the load system;

the DSP control instruction arithmetic unit (10-3) is used for calculating control instruction parameters of the reactive power phase shifter (5), the harmonic/active converter (6), the power grid compensation device (7), the inductance regulation controller (8) and the system protection controller (9), controlling the grid-connected inductance transformer (2), and sending active power generated by the reactive power phase shifter (5) and the harmonic/active converter (6) and compensation voltage current generated by the power grid compensation device (7) into a power grid;

and the DSP system protection instruction arithmetic unit (10-4) calculates the control instruction and parameters of the system protection controller (9) by the DSP system protection instruction arithmetic unit (10-4) according to the voltage current and the running state signals of the power grid and the load system output by the A/D converter (4), the power grid protection operation rule, the driving structure characteristics of the isolating switch (1) and the over-voltage, over-current and over-temperature tolerance values set by each power device.

4. The intelligent active filter according to claim 3, wherein the DSP-FFT intelligent controller (10) further comprises any one or more of the following:

-said DSP-FFT intelligent controller (10), calculating by the DSP-FFT analysis processor (10-2) the frequency, phase and amplitude of the grid reactive power and the harmonics, i.e. the initial phase of the reactive power in the reactive power region, the instantaneous value and the final phase of the reactive power in each period of the grid power waveform, controlling the reactive power phase shifter (5), shifting the phase of the reactive power generated by the grid and the load system to the active power in phase with the grid voltage, and feeding back to the grid via the grid inductance transformer (2);

-said DSP-FFT intelligent controller (10), calculating the voltage and current of the grid and load system and the frequency phase and amplitude of each harmonic power by the DSP-FFT analysis processor (10-2), controlling the harmonic/active converter (6), converting the grid harmonic into active power, and returning to the grid via the grid-connected inductive transformer (2);

the DSP-FFT intelligent controller (10) calculates and predicts the change rule of harmonic wave, reactive power and interference fluctuation impact power of the power grid through a DSP-FFT analysis processor (10-2) according to the output signal of the A/D converter (4), controls a power grid compensation device (7) to generate a suppression control signal and a power grid compensation voltage current for the harmonic wave, the reactive power and the interference fluctuation power of the power grid, sends the suppression control signal and the power grid compensation voltage current to the power grid through a grid-connected inductance transformer (2), and performs suppression control and compensation on the harmonic wave, the reactive power and the interference fluctuation power of the power grid.

5. The smart active filter according to claim 2, characterized in that the grid-connected inductive transformer (2) comprises: tuning inductance winding (2-1), inductance regulation and control winding (2-2), reactive phase shift electric energy return winding (2-3), harmonic/active conversion electric energy return winding (2-4), electric network compensation winding (2-5), transformation grid-connected winding (2-6) and high-voltage capacitor C, wherein: the inductance regulating and controlling winding (2-2) is controlled by an inductance regulating controller (8), the inductance value of the tuning inductance winding (2-1) is regulated and controlled, the inductance value of the tuning inductance winding (2-1) is connected with a high-voltage capacitor C to form an adjustable LC resonance circuit, and then all subharmonics flow into the harmonic/active converter (6); then, a DSP-FFT intelligent controller (10) controls a harmonic/active power converter (6) to convert the harmonic of the power grid into active power with the same frequency and the same phase as the voltage of the power grid, and the active power is returned to the power grid through a harmonic/active power conversion electric energy return winding (2-4) and a transformation grid-connected winding (2-6);

the DSP-FFT intelligent controller (10) controls a reactive power phase shifter (5) to shift the reactive power of the power grid into active power, and the active power is returned to the power grid through a reactive phase-shifting power return winding (2-3) and a voltage transformation grid-connected winding (2-6);

and the DSP-FFT intelligent controller (10) controls the power grid compensation voltage current output by the power grid compensation device (7) to flow to the power grid compensation winding (2-5), and the power grid compensation voltage current are boosted and sent to a power grid through the power grid compensation winding (2-5) and the transformation grid connection winding (2-6).

6. A smart active filter according to claim 2, characterized in that the grid detection means (3) comprise: the detection device (3-1) and the signal conversion sensor (3-2) are used for detecting the power grid and the load system, respectively converting voltage, current and running state signals of the power grid and the load system into low-voltage analog signals to be input into the A/D converter (4), and converting the low-voltage analog signals into digital signals by the A/D converter (4) to be input into the DSP-FFT intelligent controller (10);

the DSP-FFT intelligent controller (10) detects and monitors the power grid and the load system in real time through the power grid detection device (3), when the power grid or the load system is abnormal and fails, the DSP-FFT intelligent controller (10) controls the system protection controller (9) and the isolating switch (1), the intelligent active filter is disconnected from the power grid, and meanwhile, a notification alarm signal is sent through the communication alarm device (11); when the power grid or the load system is recovered to be normal, a normal notification signal is sent out through the communication alarm device (11), and the DSP-FFT intelligent controller (10) controls the system protection controller (9) to be switched on and connected with the isolating switch (1).