CN102982963B - Electromagnet power source and control method and digital controller thereof - Google Patents

Abstract

An electromagnet power supply, comprising: a digital controller, based on a preset reference current signal and a sense current signal corresponding to the output current of the electromagnet power supply, to generate a control current signal; a modulator, based on the control The current signal is used to generate a power device control signal; the power device draws electric energy from the main power supply according to the power device control signal to provide the output current to the electromagnet load; and a current sensor is arranged at the output end of the electromagnet power supply to generate the sensing current signal. A method and digital controller for controlling the electromagnet power supply.

Description

Electromagnet power supply and its control method and digital controller

technical field

The application relates to an electromagnet power supply and a method thereof, in particular to a digital dynamic electromagnet power supply with precise current control, a method and a digital controller for precise current control of a digital dynamic electromagnet power supply.

Background technique

With the development of digital control technology, the accelerator electromagnet power supply is developing towards the direction of full digital control. The static electromagnet power supply system of the accelerator, which is currently under construction or has been completed, has basically realized full digital control. However, in the dynamic electromagnet power supply with a repetition frequency of 10 Hz and above, there is no report on the use of fully digital control power supply technology.

According to the investigation, at present, the excitation power supply of the dynamic electromagnet of the accelerator with a repetition frequency of 10 Hz and above adopts the control technology based on the analog circuit. For example, the main electromagnets of Japan's J-PARK fast-cycle synchrotron (RCS) and the British ISIS RCS ring use 25Hz and 50Hz dynamic excitation power supplies, and the main electromagnets of many synchrotron light sources in the world also use 10Hz dynamic excitation power. power supply.

Since the load of the accelerator power supply is an electromagnet with a large inertia link, its time constant is large. At the same time, due to the special requirements for output tracking accuracy, voltage ripple and high current stability, as well as the high-frequency wave circuit of the subsequent stage, the closed-loop stable output is caused. Difficulties in correcting proportional-integral-derivative (PID) regulators.

For dynamic power supplies with a repetition rate of 10 Hz and above, existing accelerators have adopted a topology based on White resonant circuits. Since the PID closed-loop controller of the power supply itself based on the analog circuit cannot meet the precise tracking of the dynamic current of the power supply, an expensive remote control system independent of the power supply system is used to achieve precise control of the dynamic output current. Such a control system is generally based on the VME bus (VersaModule Eurocard bus, a general-purpose computer bus) architecture, or includes precise control of high-precision analog-to-digital converters (ADC) and digital-to-analog converters (DAC) Algorithm and interface design, or analog circuits including amplitude and phase detection and closed-loop control that require precise temperature control, not only the software driver and interface design and hardware design are complicated, but the entire system is very expensive.

Contents of the invention

In order to solve one of the above technical problems, the present application provides an electromagnet power supply, including: a digital controller, based on a preset reference current signal and a sense current signal corresponding to the output current of the electromagnet power supply, to generating a control current signal; a modulator generating a power device control signal based on the control current signal; a power device drawing electrical energy from a main power supply according to the power device control signal to provide the output current to an electromagnet load; and a current A sensor is arranged at the output end of the electromagnet power supply to generate the sensing current signal. Wherein, the digital controller includes: an analog-to-digital converter, which samples the sense current signal based on a preset sampling frequency to obtain a sense current signal sample; a discrete Fourier analyzer, based on the reference current signal The frequency of the fundamental component frequency and the sampling frequency perform discrete Fourier analysis on the sampling of the sensing current signal to obtain the corresponding feedback DC component amplitude, feedback fundamental component amplitude and feedback fundamental component phase; the first comparator, Comparing the amplitude of the DC component of the reference current signal with the amplitude of the feedback DC component to obtain a first comparison result; the second comparator compares the amplitude of the fundamental component of the reference current signal with the amplitude of the feedback fundamental Wave component amplitudes are compared to obtain a second comparison result; the third comparator compares the phase of the fundamental component of the reference current signal with the phase of the feedback fundamental component to obtain a third comparison result; the first digital ratio Integral-derivative controller, which generates a modified DC component amplitude according to the first comparison result; a second digital proportional-integral-derivative controller, which generates a modified fundamental wave component amplitude according to the second comparison result; a third digital proportional-integral-derivative control A device that generates a corrected fundamental wave component phase according to the third comparison result; a coordinate rotation digital calculation synthesizer that converts the corrected DC component amplitude, the corrected fundamental wave component based on the fundamental component frequency and the sampling frequency The amplitude and the phase of the modified fundamental wave component are synthesized into a synthesized reference current signal; a fourth comparator compares the synthesized reference current signal with the sensed current signal sample to obtain a fourth comparison result; and a fourth digital A proportional-integral-differential controller, configured to generate the control current signal according to the fourth comparison result.

The solenoid power supply also includes a display device for displaying the parameters processed by the digital controller.

The electromagnet power supply also includes a filter circuit, which is arranged between the power device and the current sensor at the output of the power device, and is used for filtering high-frequency signals.

The modulator in the electromagnet power supply is integrated with the digital controller, and implemented in a field programmable gate array (Field Programmable Gate Array, FPGA) digital signal processing chip through a digital signal processing method, using How to handle single-precision floating-point numbers.

The discrete Fourier analyzer included in the digital controller in the electromagnet power supply adopts a double-precision floating-point number processing method when performing digital signal processing.

The analog-to-digital converter in the electromagnet power supply is a 16-bit, 100KHz and above analog-to-digital converter.

The working sampling frequency of the first digital proportional integral differential controller, the second digital proportional integral differential controller and the third digital proportional integral differential controller in the electromagnet power supply is the frequency of the fundamental wave component.

The present application also provides a method for controlling an electromagnet power supply, comprising the steps of: obtaining a sensing current signal corresponding to the output current of the electromagnet power supply; and analyzing the sensing current signal based on a preset sampling frequency Perform sampling processing to obtain sensing current signal sampling; perform discrete Fourier analysis processing on the sensing current signal sampling based on the fundamental component frequency of the reference current signal and the sampling frequency, and obtain the corresponding feedback DC component amplitude, feedback fundamental wave component amplitude and feedback fundamental wave component phase; the DC component amplitude of the reference current signal is compared with the feedback DC component amplitude to obtain a first comparison result, and the fundamental wave component amplitude of the reference current signal is value is compared with the amplitude of the feedback fundamental wave component to obtain a second comparison result, and the phase of the fundamental wave component of the reference current signal is compared with the phase of the feedback fundamental wave component to obtain a third comparison result; according to the The first comparison result generates the corrected DC component amplitude, generates the corrected fundamental component amplitude according to the second comparison result, and generates the corrected fundamental component phase according to the third comparison result; based on the fundamental component frequency and the The sampling frequency synthesizes the amplitude of the corrected DC component, the amplitude of the corrected fundamental component, and the phase of the corrected fundamental component into a synthetic reference current signal; sampling the synthetic reference current signal and the sensing current signal comparing to obtain a fourth comparison result; and generating a control current signal according to the fourth comparison result, and controlling the output current of the electromagnet power supply according to the control current signal.

The sampling process in the method is carried out with a 16bit, 100KHz and above analog-to-digital converter.

In the method, the corrected DC component amplitude is generated according to the first comparison result, the corrected fundamental component amplitude is generated according to the second comparison result, and the corrected fundamental wave component amplitude is generated according to the third comparison result. In the steps of correcting the phase of the fundamental wave component and generating the control current signal according to the fourth comparison result, a single-precision floating-point number processing method is adopted.

In the method, the discrete Fourier analysis process adopts a double-precision floating-point number processing method.

Each step in the method is divided into a plurality of blocks, and pipeline processing is adopted.

In the method, in the same divided block, the same modules are time-division multiplexed.

The present application also provides a digital controller for generating a control current signal in an electromagnet power supply based on a preset reference current signal and a sense current signal corresponding to the output current of the electromagnet power supply, the The electromagnet power supply also includes: a modulator for generating a power device control signal based on the control current signal; a power device for drawing electric energy from a main power supply according to the power device control signal to provide the output current to the electromagnet load; and A current sensor is arranged at the output terminal of the electromagnet power supply to generate the sensed current signal, wherein the digital controller includes: an analog-to-digital converter, which senses the sensed current signal based on a preset sampling frequency The current signal is sampled to obtain the sensing current signal sampling; the discrete Fourier analyzer performs discrete Fourier analysis processing on the sensing current signal sampling based on the fundamental component frequency of the reference current signal and the sampling frequency to obtain the corresponding The amplitude of the feedback DC component, the amplitude of the feedback fundamental wave component, and the phase of the feedback fundamental wave component; the first comparator compares the amplitude of the DC component of the reference current signal with the amplitude of the feedback DC component to obtain a first comparison Result; the second comparator compares the amplitude of the fundamental component of the reference current signal with the amplitude of the feedback fundamental component to obtain a second comparison result; the third comparator compares the amplitude of the fundamental component of the reference current signal The phase of the wave component is compared with the phase of the feedback fundamental wave component to obtain a third comparison result; the first digital proportional-integral-derivative controller generates a corrected DC component amplitude according to the first comparison result; the second digital proportional-integral-differential control A controller, which generates a revised fundamental wave component amplitude according to the second comparison result; a third digital proportional-integral-derivative controller, which generates a revised fundamental wave component phase according to the third comparison result; a coordinate rotation digital calculation synthesizer, based on the The fundamental component frequency and the sampling frequency synthesize the corrected DC component amplitude, the corrected fundamental component amplitude and the corrected fundamental component phase into a composite reference current signal; the fourth comparator combines the composite The reference current signal is compared with the sensing current signal sample to obtain a fourth comparison result; and a fourth digital proportional-integral-derivative controller is configured to generate the control current signal according to the fourth comparison result.

According to the technical solution of the application, in the digital dynamic electromagnet excitation power supply, not only the digital control of the current closed loop is realized, but also the precise control of the output current of the dynamic electromagnet power supply can be realized by processing the reference waveform of the electromagnet power supply. Moreover, there is no need to change the hardware structure of the main body of the electromagnet power supply, and it is not necessary to design an independent remote control system for the dynamic electromagnet power supply that requires precise temperature control with a fast given interface, thereby greatly reducing the cost of the dynamic electromagnet power supply remote control system. cost, and simplifies the architecture for dynamic solenoid power control.

Description of drawings

Embodiments of the application will be described below with reference to the accompanying drawings, in which:

Fig. 1 exemplarily shows the block diagram of the composition of the digitized dynamic electromagnet power supply of current precision control of the present application;

Fig. 2 exemplarily shows the schematic diagram of the composition of the digital controller 10 in the digitized dynamic electromagnet power supply of the current precision control of the present application shown in Fig. 1; And

FIG. 3 exemplarily shows a flow chart of the method for precise current control of a digitized dynamic electromagnet power supply according to the present application.

Detailed ways

The present application will be described in detail below with reference to FIGS. 1 to 3 . It should be noted that in the drawings of the application described below, elements or modules with the same reference numerals have the same function in the system; A black dot "·" on the dot indicates that the intersection is a connection point or a signal branch point, and an intersection without a black dot "·" indicates that the intersection is not a connection point or a signal branch point but only passes through each other ;The coil shown is a schematic diagram of the magnet load and does not represent any parameter of the magnet load.

Fig. 1 schematically shows a block diagram of the composition of the digitized dynamic electromagnet power supply with precise current control of the present application. As shown in Fig. 1, the digitized dynamic electromagnet power supply 1 of the current precision control of the present application is hereinafter referred to as the electromagnet power supply 1, comprising: a digital controller 10, based on a preset reference current signal i and corresponding to the electromagnet power supply 1 The sensing current signal i _L of the output current _IL to generate the control current signal i _C ; the modulator 20 generates the power device control signal S based on the control current signal i _C ; the power device 30 generates the power device control signal S according to the power device control signal S from the main power supply draws electrical energy to provide an output current I _L to the electromagnet load L; and a current sensor 50 disposed at the output terminal O of the electromagnet power supply 1 to generate a sense corresponding to the output current _IL of the electromagnet power supply 1 current signal i _L . As shown in FIG. 1 , the output current I _L of the electromagnet power supply 1 is drawn from the output terminal O of the electromagnet power supply 1 by the electromagnet load L and flows into the ground G. The digital closed-loop controlled dynamic electromagnet power supply of the present application can realize precise control of the output current of the dynamic power supply.

As another embodiment of the present application, the electromagnet power supply 1 of the present application may also include a display device to display various parameters processed by the digital controller 10 .

As another embodiment of the present application, the electromagnet power supply 1 of the present application may also include a filter circuit 40, which is arranged at the output of the power device 30, that is, between the power device 30 and the current sensor 50, for filtering out high-frequency signals , so as to reduce the influence of the high frequency signal on the current sensor 50 .

As another embodiment of the present application, the modulator 20 and the digital controller 10 in the electromagnet power supply 1 of the present application are integrated together, and implemented in an FPGA digital signal processing chip through a digital signal processing method, using single-precision floating How points are handled.

In addition, the modulator 20 of the present application may be various known drivers for driving power elements, the power device 30 of the present application is, for example, various known power elements for controlling current, and the filter circuit 40 of the present application is, for example, It is a variety of well-known filter circuits for filtering out high-frequency signals, and the current sensor 50 of the present application is, for example, a variety of well-known precision current sensors for sensing current, so they will not be described in more detail.

This application adopts the method of digital signal processing to realize the precise control of the output current I _L of the electromagnet power supply such as the accelerator digitized dynamic excitation power supply. The expected ideal output current I _L =I _DC -I _AC ×cosω ₀ t, where ω ₀ =2πf ₀ , f ₀ is the dynamic operating frequency of the electromagnet power supply, I _DC and I _AC are the electromagnet power supply The magnitude of the DC component and the AC component of the output current _IL . The electromagnet power supply and method of the present application are suitable for dynamic excitation sources of high-power inertial loads that require good tracking characteristics, such as voltage ripple, current stability and other output parameter technical indicators.

In this application, by adding a specially designed digital closed-loop controller, that is, the digital controller 10 described in detail below in FIG. one.

FIG. 2 exemplarily shows a schematic diagram of the composition of the digital controller 10 in the digitized dynamic electromagnet power supply for precise current control of the present application shown in FIG. 1 . As shown in Fig. 2, the digital controller 10 in the digitized dynamic electromagnet power supply of the current precision control of the present application is hereinafter referred to as the digital controller 10, comprises: ADC140, based on preset sampling frequency f _S pair corresponding electromagnet Sampling the sensing current signal i _L of the output current _IL of the power supply 1 to obtain the corresponding sensing current signal sampling i _L '; the discrete Fourier (DFT) analyzer 120, based on the preset fundamental component frequency f ₀ and The preset sampling frequency f _S performs discrete Fourier analysis on the sensing current signal sampling i _L ', and obtains the corresponding feedback DC component amplitude i _D ', feedback fundamental wave component amplitude i _A ' and feedback fundamental wave component phase P'; comparator 101, compares the amplitude i _D of the DC component of the preset reference current signal i with the corresponding amplitude i _D ' of the feedback DC component, and obtains a corresponding comparison result Δi _D ; the comparator 102, Comparing the amplitude i A of the fundamental wave component of the preset reference current signal i with the amplitude i _{A '} of the corresponding feedback fundamental wave component to obtain the corresponding comparison result Δi _A ; the comparator 103 uses the preset reference The fundamental wave component phase P of the current signal i is compared with the corresponding feedback fundamental wave component phase P' to obtain the corresponding comparison result ΔP; the digital PID controller 111 generates the corresponding corrected DC component amplitude i _D according to the comparison result Δi _D "; digital PID controller 112, according to the comparison result Δi _A to generate the corresponding correction fundamental wave component amplitude i _A "; digital PID controller 113, according to the comparison result ΔP to generate the corresponding correction fundamental wave component phase P"; coordinate rotation digital Calculation (CORDIC) synthesizer 130, based on the preset fundamental component frequency f ₀ and the preset sampling frequency f _S , will correct the DC component amplitude i _D ″, correct the fundamental component amplitude i _A " and the modified fundamental component phase P" are synthesized into a new synthesized reference current signal i'; the comparator 104 compares the synthesized reference current signal i' with the sensing current signal sampling i _L ', and obtains a comparison result Δi'; digital The PID controller 114 generates a control current signal i _C for controlling the output current I _L of the electromagnet power supply 1 according to the comparison result Δi′. Wherein, the fundamental component frequency f ₀ is the preset frequency of the fundamental component of the reference current signal i, that is, the desired dynamic operating frequency of the output current I _L of the electromagnet power supply under ideal conditions. In addition, the clock of the sampling frequency f _S of the ADC 140 is related to the sampling frequency f _S based on which the CORDIC synthesizer 130 outputs a new reference waveform, that is, the synthetic reference current signal i′, and the sampling frequency based on the discrete Fourier (DFT) analyzer 120 The clock of f _S should be a clock of the same source and frequency.

For example, the ADC 140 of the present application samples the sensing current signal i _L corresponding to the output current _IL of the electromagnet power supply 1 through a 16-bit, 100 KHz and above high-resolution and high-speed ADC. By performing DFT analysis on the current feedback value sampled by ADC140, that is, the sensing current signal sampling i _L ', the corresponding feedback DC component amplitude i _D ', feedback fundamental wave component amplitude i _A ' and feedback fundamental wave component phase P '. Precise control of each sampling period of ADC140, that is, the sampling frequency signal and the fundamental frequency f ₀ , helps to ensure the feedback DC component amplitude i _D ', the feedback fundamental component amplitude i _A ' and the feedback fundamental component in DFT analysis The accuracy of the phase P' ensures the precise control of the output current I _L of the dynamic power supply.

As shown in Fig. 1 and Fig. 2, the present application realizes the DC amplitude and the fundamental amplitude of the output current _IL of the electromagnet power supply 1 respectively by adopting three digital PID controllers 111 to 113. And precise closed-loop control of the fundamental phase. The preset value of the DC amplitude i _D , the fundamental amplitude i _A and the fundamental phase P of the reference current signal i correspond to the ideal excitation curve of the electromagnet, that is, the ideal sinusoidal excitation current with DC bias set value. The DC amplitude, fundamental wave amplitude and fundamental wave phase of the output current I _L of the electromagnet power supply 1 correspond to the feedback DC component amplitude i _D ', feedback fundamental wave component amplitude i _A ' and Feedback fundamental component phase P'. Then the three digital PID controllers 111 to 113 respectively generate the corrected DC component amplitude i _D ”, the corrected fundamental wave component amplitude i _A ” and the corrected fundamental wave component phase P”. Then the CORDIC The coordinate rotation digital calculation method of the synthesizer 130 synthesizes a new current reference curve, that is, the reference current signal i'. Then the comparator 104 directly compares the reference current signal i' with the sensing current signal sample i _L ' sampled by the ADC140. The output of the comparator 104 is converted by another digital PID controller 114 of current closed-loop control, and the output of the digital PID controller, namely the control current signal i _C , is converted by the modulator 20 in the electromagnet power supply 1 to act on the power device 30 The power device control signal S on the power device 1. The power device 30 in the electromagnet power supply 1 adjusts its own switch or conduction according to the power device control signal S to control the output current I _L of the electromagnet power supply 1, thereby realizing the electromagnet power supply 1 for precise control of the output current _IL .

As another embodiment of the present application, the working sampling frequency of the three digital PID controllers 111 to 113 of the present application may be the fundamental component frequency f ₀ .

As another embodiment of the present application, when the DFT analyzer 120 of the present application performs digital signal processing, in order to ensure the accuracy of the DFT output, a double-precision floating-point number processing method may be used.

As another embodiment of the present application, the digital PID controller of the present application may adopt a single-precision floating-point number processing manner.

Corresponding to the digitized dynamic electromagnet power supply with precise current control of the present application described in conjunction with FIGS. .

As shown in Fig. 3, the method for current precision control digitized dynamic electromagnet power supply of the present application includes the following steps:

Step S200 , the current sensor 50 provided at the output terminal O of the electromagnet power supply 1 obtains a sensing current signal i _L corresponding to the output current I _L of the electromagnet power supply 1 .

In step S210, the ADC 140 in the digital controller 10 samples the sensing current signal i _L based on a preset sampling frequency f _S to obtain a corresponding sensing current signal sample i _L ′.

Step S220, the DFT analyzer 120 in the digital controller 10 performs DFT analysis on the sensing current signal sample i _L ' based on the preset fundamental component frequency f ₀ and the preset sampling frequency f _S to obtain Corresponding feedback DC component amplitude i _D ', feedback fundamental wave component amplitude i _A ' and feedback fundamental wave component phase P'.

Step S230, the comparator 101, the comparator 102 and the comparator 103 in the digital controller 10 respectively compare the DC component amplitude i _D , the fundamental wave component amplitude i _A and the fundamental wave component phase P of the reference current signal i with the corresponding The feedback DC component amplitude i _D ', the feedback fundamental wave component amplitude i _A ' and the feedback fundamental wave component phase P' are compared to obtain corresponding comparison results Δi _D , Δi _A and ΔP.

Step S240, _the digital _PID controller 111, the digital PID controller 112 and the digital PID controller 113 in the digital controller 10 respectively generate corresponding corrected DC component amplitudes i _D ″, corrected Fundamental wave component amplitude i _A ” and corrected fundamental wave component phase P”.

_In step S250, the CORDIC synthesizer 130 in the digital controller 10 will modify the DC component amplitude i _{D ″} , the fundamental wave The component amplitude i _A ″ and the corrected fundamental wave component phase P” are synthesized into a new synthesized reference current signal i'.

In step S260, the comparator 104 in the digital controller 10 compares the synthesized reference current signal i' with the sensing current signal sample i _L ', and obtains a comparison result Δi'.

In step S270, the digital PID controller 114 in the digital controller 10 generates a control current signal i _C according to the comparison result Δi'.

In step S280, the modulator 20 in the electromagnet power supply 1 generates a power device control signal S according to the control current signal i _C.

In step S290, the power device 30 in the electromagnet power supply 1 controls the output current I _L of the electromagnet power supply 1 according to the power device control signal S.

After step S290 is completed, return to step S200.

Wherein, in step S240 and step S270, the digital PID controller 111, the digital PID controller 112 and the digital PID controller 113 in the digital controller 10 respectively generate corresponding corrected DC components according to the comparison results Δi _D , Δi _A and ΔP amplitude i _D ”, corrected fundamental wave component amplitude i _A ” and corrected fundamental wave component phase P”, and the digital PID controller 114 in the digital controller 10 generates the control current signal i _C according to the comparison result Δi′. A processing method of single-precision floating-point numbers may be used. In step S220, the discrete Fourier analysis may use a processing method of double-precision floating-point numbers.

As another embodiment of the present application, in order to realize complex digital algorithms within limited FPGA resources, the method for current precision control of the digital dynamic electromagnet power supply of the entire application can be divided into multiple blocks, for example, the above steps S200 to step S290 are divided into multiple blocks, and pipeline processing is adopted to improve the operation speed.

As another embodiment of the present application, in addition, within the same divided block, the same modules are time-division multiplexed, which can save FPGA logic resources.

Through the description of the digital dynamic electromagnet power supply and its method for precise current control of the present application in conjunction with FIGS. The digital control of the electromagnet power supply, and through the processing of the reference waveform of the electromagnet power supply, the precise control of the output current of the dynamic electromagnet power supply can be realized. Moreover, there is no need to change the hardware structure of the main body of the electromagnet power supply, and it is not necessary to design an independent remote control system for the dynamic electromagnet power supply that requires precise temperature control with a fast given interface, thereby greatly reducing the cost of the dynamic electromagnet power supply remote control system. cost, and simplifies the architecture for dynamic solenoid power control.

While the present application has been described with reference to exemplary embodiments, it is understood that the words which have been used are words of description and illustration, rather than of limitation. As the present application can be embodied in many forms, it should be understood that the above-described embodiments are not limited to any of the foregoing details, but are to be construed broadly within the scope of the appended claims, and therefore fall within the claims or their equivalents All changes and modifications within are intended to be covered by the appended claims.

Claims (14)

1. An electromagnet power supply, comprising: a digital controller, generating a control current signal based on a preset reference current signal and a sensing current signal corresponding to the output current of the electromagnet power supply; a modulator for generating a power device control signal based on the control current signal; a power device, drawing electric energy from a main power supply according to the power device control signal to provide the output current to the electromagnet load; and a current sensor disposed at the output of the electromagnet power supply to generate the sensed current signal, Wherein, the digital controller includes: An analog-to-digital converter that samples the sensing current signal based on a preset sampling frequency to obtain sensing current signal samples; A discrete Fourier analyzer, based on the frequency of the fundamental component of the reference current signal and the sampling frequency, performs discrete Fourier analysis on the sampling of the sensing current signal to obtain the corresponding amplitude of the feedback DC component and the amplitude of the feedback fundamental component and the phase of the feedback fundamental component; The first comparator compares the amplitude of the DC component of the reference current signal with the amplitude of the feedback DC component to obtain a first comparison result; The second comparator compares the amplitude of the fundamental wave component of the reference current signal with the amplitude of the feedback fundamental wave component to obtain a second comparison result; a third comparator, which compares the phase of the fundamental component of the reference current signal with the phase of the feedback fundamental component to obtain a third comparison result; A first digital proportional-integral-differential controller, generating a corrected DC component amplitude according to the first comparison result; A second digital proportional-integral-derivative controller, generating a modified fundamental wave component amplitude according to the second comparison result; A third digital proportional-integral-differential controller, generating a corrected fundamental wave component phase according to the third comparison result; A coordinate rotation digital calculation synthesizer, which synthesizes the corrected DC component amplitude, the corrected fundamental component amplitude, and the corrected fundamental component phase into a synthetic reference current signal based on the fundamental component frequency and the sampling frequency ; a fourth comparator, which compares the synthesized reference current signal with the sensed current signal sample to obtain a fourth comparison result; and The fourth digital proportional-integral-differential controller generates the control current signal according to the fourth comparison result. 2. The electromagnet power supply according to claim 1, further comprising: A display device for displaying parameters processed by the digital controller. 3. The electromagnet power supply according to claim 1, further comprising: A filter circuit, arranged between the power device and the current sensor at the output of the power device, is used to filter out high-frequency signals. 4. The electromagnet power supply according to claim 1, wherein, The modulator and the digital controller are integrated together, implemented in a field programmable gate array digital signal processing chip through a digital signal processing method, and adopt a single-precision floating-point number processing method. 5. The electromagnet power supply according to claim 1, wherein, The analog-to-digital converter is a 16-bit, 100KHz and above analog-to-digital converter. 6. The electromagnet power supply according to claim 1, wherein, The working sampling frequency of the first digital proportional integral differential controller, the second digital proportional integral differential controller and the third digital proportional integral differential controller is the frequency of the fundamental component. 7. The electromagnet power supply according to claim 1, wherein, The discrete Fourier analyzer adopts a double-precision floating-point number processing method when performing digital signal processing. 8. A method of controlling an electromagnet power supply, comprising the steps of: obtaining a sensing current signal corresponding to the output current of the electromagnet power supply; Sampling the sensing current signal based on a preset sampling frequency to obtain sensing current signal samples; Perform discrete Fourier analysis on the sensing current signal sampling based on the fundamental component frequency of the reference current signal and the sampling frequency to obtain the corresponding feedback DC component amplitude, feedback fundamental component amplitude, and feedback fundamental component phase; Comparing the magnitude of the DC component of the reference current signal with the magnitude of the feedback DC component to obtain a first comparison result, and comparing the magnitude of the fundamental component of the reference current signal with the magnitude of the feedback fundamental component comparing to obtain a second comparison result, and comparing the phase of the fundamental component of the reference current signal with the phase of the feedback fundamental component to obtain a third comparison result; generating a corrected DC component amplitude according to the first comparison result, generating a corrected fundamental component amplitude according to the second comparison result, and generating a corrected fundamental component phase according to the third comparison result; synthesizing the corrected DC component amplitude, the corrected fundamental component amplitude, and the corrected fundamental component phase into a composite reference current signal based on the fundamental component frequency and the sampling frequency; Comparing the synthesized reference current signal with the sensed current signal samples to obtain a fourth comparison result; and A control current signal is generated according to the fourth comparison result, and a power device control signal is generated according to the control current signal to control the output current of the electromagnet power supply. 9. The method of claim 8, wherein, The sampling process is carried out with 16bit, 100KHz and above analog-to-digital converters. 10. The method of claim 8, wherein, In the step of generating the corrected DC component amplitude according to the first comparison result, generating the corrected fundamental wave component amplitude according to the second comparison result, and generating the corrected fundamental wave component according to the third comparison result In the step of phase and generating the control current signal according to the fourth comparison result, a single-precision floating-point number processing method is adopted. 11. The method of claim 8, wherein, The discrete Fourier analysis process adopts a double-precision floating-point number processing method. 12. The method of claim 8, wherein, Each step is divided into a plurality of blocks, and pipeline processing is adopted. 13. The method of claim 12, wherein, In the same divided block, the same modules are time-division multiplexed. 14. A digital controller for generating a control current signal in an electromagnet power supply based on a preset reference current signal and a sensing current signal corresponding to an output current of the electromagnet power supply, the electromagnet power supply Also comprising: a modulator, generating a power device control signal based on the control current signal; a power device, drawing electric energy from a main power supply according to the power device control signal to provide the output current to an electromagnet load; and a current sensor, Set at the output end of the electromagnet power supply to generate the sense current signal, wherein the digital controller includes: An analog-to-digital converter that samples the sensing current signal based on a preset sampling frequency to obtain sensing current signal samples; A discrete Fourier analyzer, based on the frequency of the fundamental component of the reference current signal and the sampling frequency, performs discrete Fourier analysis on the sampling of the sensing current signal to obtain the corresponding amplitude of the feedback DC component and the amplitude of the feedback fundamental component and the phase of the feedback fundamental component; The first comparator compares the amplitude of the DC component of the reference current signal with the amplitude of the feedback DC component to obtain a first comparison result; The second comparator compares the amplitude of the fundamental wave component of the reference current signal with the amplitude of the feedback fundamental wave component to obtain a second comparison result; a third comparator, which compares the phase of the fundamental component of the reference current signal with the phase of the feedback fundamental component to obtain a third comparison result; A first digital proportional-integral-differential controller, generating a corrected DC component amplitude according to the first comparison result; A second digital proportional-integral-derivative controller, generating a modified fundamental wave component amplitude according to the second comparison result; A third digital proportional-integral-differential controller, generating a corrected fundamental wave component phase according to the third comparison result; A coordinate rotation digital calculation synthesizer, which synthesizes the corrected DC component amplitude, the corrected fundamental component amplitude, and the corrected fundamental component phase into a synthetic reference current signal based on the fundamental component frequency and the sampling frequency ; a fourth comparator, which compares the synthesized reference current signal with the sensed current signal sample to obtain a fourth comparison result; and The fourth digital proportional-integral-differential controller generates the control current signal according to the fourth comparison result.