CN102983589A - Control method of grid friendly type distributed power source based on hybrid energy storage - Google Patents

Abstract

The invention provides a control method of a grid friendly type distributed power source based on hybrid energy storage. The method comprises the steps of optimally designing a topology structure of the distributed power source, controlling a direct current power supply system in a coordinating mode through a direct current (DC)/DC converter controlling a model normalization model, and self-adaptively controlling a grid of an alternating current (AC) side DC /AC converter. The distributed power source not only can be connected in a large grid to operate so as to reduce the influence of intermittent renewable energy power generation grid connection on the grid and provide support of voltage and frequency for the grid, but also can be connected into a micro-grid to operate as a network unit of the off-network type micro-grid to maintain stability of voltage and frequency of the off-network type micro-grid. When an outer grid breaks down, the distributed power source can realize switch between a grid mode and an island mode so as to improve power supply reliability of important loads in the system. The distributed power source improves technical performance and economic performance of the whole system through matching utilization of an energy type system and a power type energy storage system.

Description

The control method of the friendly type distributed power source of a kind of electrical network based on hybrid energy-storing

Technical field

The present invention relates to distributed power source operation and control, be specifically related to a kind of control method of the friendly type distributed power source of electrical network based on hybrid energy-storing.

Background technology

Realize that the control strategy of distributed power source AC converter and effective utilization of hybrid energy-storing are the key technical problems that emphasis need to solve based on the friendly characteristic of electrical network of the distributed power source of hybrid energy-storing.

(1) distributed power source control strategy

Batch (-type) renewable energy power generation, especially wind power generation and photovoltaic generation, its exert oneself have intermittence, the characteristics such as fluctuation and uncontrollability, if be incorporated into the power networks, can bring a series of impact to the safety and stability of electrical network.In order to reduce renewable energy source power to the impact of electrical network, can stabilize the power fluctuation of renewable energy power generation with the renewable energy power generation unit of energy-storage system, the distributed power generation unit is carried out deciding power control, can make it control its power output according to dispatch command.But, outstanding along with environment and energy problem, distributed power source shared ratio in electrical network is increasing, in order to guarantee the safe and reliable operation of electrical network, also more and more higher to the distributed power source requirement in the standard that is incorporated into the power networks, need distributed power source to possess certain line voltage and frequency supporting role, and adopt the distributed power source of deciding power control also not possess this function.

In little electrical network, the control method of distributed power source has V-F control, P-Q control, Droop to control three types, adopts the distributed power source of Droop control to possess certain line voltage supporting role, can be used as the networking unit operation of little electrical network.But adopt the distributed power source of Droop control to be applied in little electrical network, also there is certain problem, as not considering the impedance model of circuit, can not be applicable to little electrical network of various line impedance models, do not possess and conventional unit between power-sharing effect etc., and also more rare for the seamless switching control of the little power supply that adopts this kind control strategy.

(2) hybrid energy-storing control technology

In the Distributed Renewable Energy Power System with energy-storage system, usually select storage battery as energy-storage travelling wave tube, but storage battery as the energy-storage travelling wave tube of energy type, have that power density is low, charge and discharge cycles times influence its useful life etc. shortcoming.Super capacitor is as the power-type energy-storage travelling wave tube, because the advantages such as its power density is high, have extended cycle life, efficiency for charge-discharge height, Maintenance free, just receive increasing concern, but because its energy density is lower, also be difficult to realize at present jumbo electric power energy storage.Storage battery and ultracapacitor mixed use, be applied to renewable energy system, make the large and super capacitor power density of storage battery energy density greatly, the characteristics that have extended cycle life combine, and can greatly promote technical performance and the economic performance of whole system.

At present, existing researcher is applied to electric automobile, compact power and renewable energy source domain for hybrid energy-storing and did some researchs, has mainly proposed following several hybrid energy-storing structures:

(1) storage battery and ultracapacitor are directly in parallel.Storage battery, the direct parallel connection of ultracapacitor is the simplest a kind of hybrid energy-storing structure, adopt this structure, can be when fluctuation occurs in load, significantly reduce the maximum output current of storage battery during the fluctuation of load, improve the maximum power output ability of mixed energy storage system, but in this structure, because the terminal voltage of batteries is forced to equate with the terminal voltage of bank of super capacitors, cause the capacity of super capacitor utilance low, connection in series-parallel compound mode to bank of super capacitors in design requires also comparatively strict, and the course of work of storage battery can not be set flexibly, can not realize the efficient utilization of dissimilar energy storage devices.

(2) storage battery is in parallel with super capacitor by the DC/DC power inverter.Storage battery is in parallel with super capacitor by the DC/DC converter, by the appropriate design to the power inverter control strategy, can realize the charge and discharge process of batteries is carried out flexible management, the advantage of better performance ultracapacitor, improve the performance of hybrid accumulator, prolong the useful life of storage battery.But, super capacitor is directly hung on the dc bus, ultracapacitor is in charge and discharge process, and terminal voltage can change along with the variation of energy storage capacity, and the change in voltage amplitude is larger, and DC bus-bar voltage is unstable.

(3) ultracapacitor is in parallel with storage battery by the DC/DC converter.In order to obtain stable DC bus-bar voltage, there is document to propose ultracapacitor by the DC/DC converter hybrid energy-storing structure in parallel with batteries, although during power fluctuation, DC bus-bar voltage is comparatively stable, but adopt this structure, the flexible management of batteries input and output energy can not be realized equally, the effect of all kinds energy storage device can not be given full play to.

Summary of the invention

In order to overcome above-mentioned the deficiencies in the prior art, the invention provides the converter control method of the friendly type distributed power source of a kind of electrical network based on hybrid energy-storing, this distributed power source both can be incorporated large operation of power networks into, reduce intermittent renewable energy source power to the impact of electrical network, and provide voltage and frequency to support to electrical network; Also can and electrical network in a subtle way, as the networking unit operation from the little electrical network of net type, keep from voltage and the frequency stabilization of the little electrical network of net type; When external electrical network breaks down, this distributed power source can also realize being incorporated into the power networks/the double mode switching of isolated island, the power supply reliability of important load in the raising system.This distributed power source cooperates utilization by energy type and power-type energy-storage system, has improved whole system technical performance and economic performance.

In order to realize the foregoing invention purpose, the present invention takes following technical scheme:

The control method of the friendly type distributed power source of a kind of electrical network based on hybrid energy-storing is provided, said method comprising the steps of:

Step 1: the topological structure of optimal design distributed power source;

Step 2: coordinate the control DC power-supply system by DC/DC convertor controls pattern normalization model;

Step 3: the electrical network adaptive control of AC DC/AC converter.

In the topological structure of the distributed power source of described step 1, intermittent renewable energy system, lithium battery energy storage battery system and super capacitor energy-storage system are in parallel with dc bus by DC/DC converter A, DC/DC converter B and DC/DC converter C respectively, consist of the DC power-supply system of distributed power source, this DC power-supply system is connected with AC system by AC DC/AC converter, forms distributed power source.

In the described step 2, the DC/DC converter comprises DC/DC converter A, DC/DC converter B and DC/DC converter C; The control model of DC/DC converter comprises decides voltage mode control, constant current control model and permanent power control mode; Choosing of power magnitude limit value by the instruction of voltage control loop reference power, current regulator current amplitude limit value and power control loop determined above-mentioned different control model; The constant current control model comprises constant current charge control model and constant current discharge control model.

In the described DC/DC convertor controls pattern normalization model, the difference of the reference value of busbar voltage and its measured value is regulated through PI, pass through again the current limit link, obtain the reference value of energy-storage system output current, the difference of energy-storage system output current reference value and its output current measured value is regulated through PI, and then by the power limiting link, obtain the reference value of energy-storage system power output, as the switch triggering signal of DC/DC converter; Described energy-storage system comprises lithium battery energy storage battery system and super capacitor energy-storage system.

Described step 2 may further comprise the steps:

Step 2-1: tuning controller is measured DC bus-bar voltage U in real time _DC, the state-of-charge of lithium battery and the terminal voltage of super capacitor, and determine the control model of DC/DC converter according to Monitoring Data;

Step 2-2: tuning controller is measured the load power P of the friendly type distributed power source of described electrical network in real time _lPower output P with intermittent renewable energy system _r, calculate the power shortage P of described mixed energy storage system _s, P _s=P _l-P _r, and extract P _sIn low frequency component P _{B_ref}, described P _{B_ref}Be the value and power reference of permanent power control mode lithium battery energy storage battery system, P _lBe the load power of distributed power source, P _rPower output for intermittent renewable energy system;

Step 2-3: when DC bus-bar voltage drops on zone 1, i.e. U ₀＜U _DC＜U ₁The time, DC/DC converter A is operated in and decides voltage mode control, and its reference voltage is got U _Ref1, the current amplitude limit value of current regulator and the power magnitude limit value of power control loop are got respectively I _Max1And P _Max1DC/DC converter B and DC/DC converter C do not work;

Wherein: U ₀The maximum that-DC bus-bar voltage allows;

U _DCThe real-time measurement values of-DC bus-bar voltage;

U _Ref1-DC bus-bar voltage dropped on regional 1 o'clock, the fixed voltage-controlled voltage reference value of DC/DC converter A, and its choosing value is positioned at zone 1, i.e. U ₀＜U _Ref1＜U ₁

I _Max1-DC/DC converter A current regulator allows the current maxima passed through;

P _Max1-DC/DC converter A power control loop allows the maximum power sent;

Step 2-4: when DC bus-bar voltage drops on zone 2, i.e. U ₂＜U _DC＜U ₁The time, DC/DC converter A is operated in the MPPT control model, and DC/DC converter B is operated in and decides voltage mode control, and its reference voltage is got U _Ref2, the current amplitude limit value of current regulator and the power magnitude limit value of power control loop are got respectively I _Max2And P _Max2DC/DC converter C is operated in the constant current discharge control model, and the reference voltage of its voltage control loop is got U _{Ref_ab}, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _{Sc_ref}And P _Max3In this process, the terminal voltage U of tuning controller Real-Time Monitoring super capacitor _UcIf detect U _Min＜U _Uc＜U _Max, change step 2-5 operation over to;

Wherein: U _Ref2-DC bus-bar voltage dropped on regional 2 o'clock, the fixed voltage-controlled voltage reference value of DC/DC converter B, and its choosing value is positioned at zone 2, i.e. U ₁＜U _Ref2＜U ₂

I _Max2-DC/DC converter B current regulator allows the current maxima passed through;

P _Max2-DC/DC converter B power control loop allows the maximum power sent;

U _{Ref_ab}The voltage reference value of DC/DC converter C voltage control loop;

I _{Sc_ref}The reference value of the super capacitor charging and discharging currents of-setting;

P _Max3-DC/DC converter C power control loop allows the maximum power sent;

U _UcThe terminal voltage of-super capacitor;

U _MinThe smallest end voltage that-super capacitor allows;

U _MaxThe maximum terminal voltage that-super capacitor allows;

Step 2-5: when DC bus-bar voltage drops on zone 3, i.e. U ₃＜U _DC＜U ₂The time, DC/DC converter A is operated in the MPPT pattern, and DC/DC converter B is operated in permanent power control mode, and the voltage reference value of its voltage control loop is got U ' _Ref-ab, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _Max2And P _Max2DC/DC converter C is operated in and decides voltage mode control, and the reference voltage of its voltage control loop is got U _Ref3, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _Max3And P _Max3

Wherein:

U ' _Ref-abThe voltage reference value of-DC/DC converter B voltage control loop;

U _Ref3-DC bus-bar voltage dropped on regional 3 o'clock, the fixed voltage-controlled voltage reference value of DC/DC converter C, and its choosing value is positioned at zone 3, i.e. U ₃＜U _Ref3＜U ₂

I _Max3-DC/DC converter C current regulator allows the current maxima passed through;

Step 2-6: when DC bus-bar voltage drops on zone 4, i.e. U ₄＜U _DC＜U ₃The time, DC/DC converter A is operated in the MPPT pattern, and the DC/DC converter B of lithium battery system is operated in and decides voltage mode control, and the voltage reference value of its voltage control loop is got U _Ref4, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _Max2And P _Max2DC/DC converter C is operated in the constant current charge control model, and the reference voltage of its voltage control loop is got U _{Ref_ab}, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _{Sc_ref}And P _Max3, in this process, the terminal voltage U of tuning controller Real-Time Monitoring super capacitor _UcIf detect U _Min＜U _Uc＜U _Max, change step 2-5 operation over to;

Wherein:

U ₄The maximum U that-DC bus-bar voltage allows ₀＞U ₁＞U ₂＞U ₃＞U ₄

U _Ref4-DC bus-bar voltage dropped on regional 4 o'clock, the fixed voltage-controlled voltage reference value of DC/DC converter B, and its choosing value should drop in the zone 4, i.e. U ₄＜U _Ref4＜U ₃

In the described step 3, AC DC/AC converter adopts the control of motor synchronizing voltage source, introduce simultaneously virtual impedance control and the control of double mode seamless switching, and to the normalized of above-mentioned control model, so that distributed power source is when incorporating the little electrical network of mesolow into, can with inverter type distributed power source or conventional synchronization motor-type distributed power source group net operation in parallel.

In the control of motor synchronizing voltage source, three-phase voltage and the electric current of the output of Real-time Collection DC/AC converter, according to instantaneous power theory, calculate active-power P and the reactive power Q of the output of DC/AC converter, adopt the control of motor synchronizing voltage source, calculate the reference frequency f of the virtual output voltage phasor of DC/AC converter _{Vir_ref}With reference amplitude V _{Vir_ref}:

$\left\{\begin{array}{c}{f}_{\mathrm{vir}-\mathrm{ref}}=f^{*}-m(P^{*}-P)\\ V_{\mathrm{vir}-\mathrm{ref}}=V^{*}-n(Q^{*}-Q)\end{array}\right.---(2-1)$

Wherein:

f _{Vir_ref}The reference frequency of the virtual output voltage phasor of-DC/AC converter;

V _{Vir_ref}The reference amplitude of the virtual output voltage phasor of-DC/AC converter;

f ^*The reference frequency of-mixed energy storage system rated voltage;

V ^*The reference amplitude of-mixed energy storage system rated voltage;

The sagging coefficient of m-meritorious/frequency droop control;

The sagging coefficient of n-REACTIVE POWER/VOLTAGE droop control;

P ^*-DC/AC converter is at f ^*The active power reference value of lower output;

Q ^*-DC/AC converter is at V ^*The reactive power reference qref of lower output;

The active power that P-the DC/AC converter sends;

The reactive power that Q-the DC/AC converter sends;

M and n through type (2-2) calculate:

$\left\{\begin{array}{c}m=\frac{f_{\min }-f^{*}}{P_{\max }-P^{*}}\\ n=\frac{V_{\min }-V^{*}}{Q_{\max }-Q^{*}}\end{array}\right.---(2-2)$

Wherein:

f _MinThe minimum operation frequency that-mixed energy storage system allows;

V _MinThe minimum operation voltage that-mixed energy storage system allows;

P _MaxThe maximum active power that-converter can be exported;

Q _MaxThe maximum reactive power that-converter can be exported;

In the virtual impedance control, (2-3) calculates according to formula

$\left\{\begin{array}{c}\stackrel{\·}{V_{\mathrm{vir}\_\mathrm{ref}}}=V_{\mathrm{vir}\_\mathrm{ref}}\∠{\mathrm{\θ}}_{\mathrm{vir}\_\mathrm{ref}}\\ {\mathrm{\θ}}_{\mathrm{vir}\_\mathrm{ref}}=2\mathrm{\π}\underset{0}{\overset{t}{\∫}}{f}_{\mathrm{vir}\_\mathrm{ref}}\mathrm{dt}\end{array}\right.---(2-3)$

$\stackrel{\·}{V_{\mathrm{ref}}}=\stackrel{\·}{V_{\mathrm{vir}\_\mathrm{ref}}}-\stackrel{\·}{I}{Z}_{\mathrm{vir}}---(2-4)$

In the formula:

The reference phasor of the virtual output voltage phasor of-DC/AC converter;

The reference phasor of-DC/AC converter output voltage phasor;

The electric current phasor that-DC/AC converter sends;

Z _Vir-virtual impedance.

In the double mode seamless switching control,

When distributed power source detected large electric network fault, the switch that is incorporated into the power networks disconnected, f ^*And V ^*Set-point change into set point under the independent operation mode by the frequency of line voltage and amplitude;

When the fault clearance of large electrical network, distributed power source is converted to when being incorporated into the power networks pattern by independent operation mode, starts the motor synchronizing control of distributed power source, wait to satisfy when being incorporated into the power networks condition, the closure switch that is incorporated into the power networks is incorporated into the power networks distributed power source, is incorporated into the power networks to the impact of electrical network to reduce distributed power source.

In the motor synchronizing control, the frequency adjusted value of DC/AC converter output voltage phasor and range-adjusting value through type (2-5) calculate:

$\left\{\begin{array}{c}\mathrm{\&Delta;f}=({\mathrm{<figure-callout\; id="1"\; label="K\; p"\; filenames="HDA00002412193600022.png"\; state="\{\{state\}\}">K</figure-callout>}}_p+\frac{K_{i1}}{s})({\mathrm{\&theta;}}_g-{\mathrm{\&theta;}}_i)\\ \mathrm{\&Delta;U}=({\mathrm{<figure-callout\; id="2"\; label="K\; p"\; filenames="HDA00002412193600021.png"\; state="\{\{state\}\}">K</figure-callout>}}_p+\frac{K_{i2}}{s})(U_g-U_i)\end{array}\right.---(2-5)$

Wherein:

The frequency adjusted value of Δ f-DC/AC converter output voltage phasor;

The range-adjusting value of Δ U-DC/AC converter output voltage phasor;

K _P1The proportional control factor of-DC/AC frequency inverter Synchronization Control;

K _I1The integral adjustment coefficient of-DC/AC frequency inverter Synchronization Control;

K _P2-DC/AC converter voltage magnitude is followed the tracks of the proportional control factor in the control;

K _I2-DC/AC converter voltage magnitude is followed the tracks of the integral adjustment coefficient in the control;

θ _gThe phase angle of-line voltage phasor;

θ _iThe phase angle of the voltage phasor that-DC/AC converter sends;

U _gThe amplitude of-line voltage phasor;

U _iThe amplitude of the voltage phasor that-DC/AC converter sends.

Compared with prior art, beneficial effect of the present invention is:

1. can be applicable to operation and control that distributed power source is incorporated into the power networks, reduce the batch (-type) renewable energy source power to the impact of electrical network, make distributed power source according to higher level's dispatch command with the scheduling Power operation, and can automatically participate in frequency, the voltage-regulation of electrical network, improve electrical network to the admittance ability of distribution type renewable energy generating, realized energy conservation and environmental protection benefit;

2. can be applicable to operation and the control of distributed power source in the little electrical network of net type, make distributed power source can be used as the networking unit of little electrical network, with the common all load powers of subsystem of conventional electric generators, other inverter type distributed power sources, keep the stable of frequency in the electrical network and voltage;

3. can be applicable to be incorporated into the power networks/the dual mode operated little electrical network of isolated island, realize the seamless switching under two kinds of patterns, improve the power supply reliability of load;

4. can be applicable to the operation control of mixed energy storage system, can the optimum management storage battery and the charge and discharge process of super capacitor, improve the course of work of storage battery, reduce its charge and discharge cycles number of times and maximum depth of discharge, prolong the useful life of energy-storage system;

5. can be applicable to comprise operation and the control of the DC power-supply system of renewable energy power generation and energy-storage system, can the stable DC busbar voltage, keep the Systems balanth operation.

Description of drawings

Fig. 1 is the control flow chart of coordinating control in the embodiment of the invention between the DC power-supply system each several part;

Fig. 2 is based on the topology diagram of the friendly type distributed power source of the electrical network of hybrid energy-storing in the embodiment of the invention;

Fig. 3 is DC/DC converter plurality of operating modes normalization control chart in the embodiment of the invention;

Fig. 4 is distributed power source DC bus-bar voltage traffic coverage schematic diagram in the embodiment of the invention;

Fig. 5 is the electrical network adaptive control flow chart of AC DC/DC converter in the embodiment of the invention.

Embodiment

Below in conjunction with accompanying drawing the present invention is described in further detail.

Such as Fig. 1, the control method of the friendly type distributed power source of a kind of electrical network based on hybrid energy-storing is provided, said method comprising the steps of:

Step 1: the topological structure of optimal design distributed power source;

Step 2: coordinate the control DC power-supply system by DC/DC convertor controls pattern normalization model;

Step 3: the electrical network adaptive control of AC DC/AC converter.

Such as Fig. 2, in the topological structure of distributed power source, intermittent renewable energy system, lithium battery energy storage battery system and super capacitor energy-storage system are in parallel with dc bus by DC/DC converter A, DC/DC converter B and DC/DC converter C respectively, consist of the DC power-supply system of distributed power source, this DC power-supply system is connected with AC system by AC DC/AC converter, forms distributed power source.

In the described step 2, the DC/DC converter comprises DC/DC converter A, DC/DC converter B and DC/DC converter C; DC/DC converter A is unidirectional DC/DC converter, and DC/DC converter B and DC/DC converter C are two-way DC/DC converter.The control model of DC/DC converter comprises decides voltage mode control, constant current control model and permanent power control mode; Choosing of power magnitude limit value by the instruction of voltage control loop reference power, current regulator current amplitude limit value and power control loop determined above-mentioned different control model; The constant current control model comprises constant current charge control model and constant current discharge control model.

Such as Fig. 3, in the described DC/DC convertor controls pattern normalization model, the difference of the reference value of busbar voltage and its measured value is regulated through PI, pass through again the current limit link, obtain the reference value of energy-storage system output current, the difference of energy-storage system output current reference value and its output current measured value is regulated through PI, and then by the power limiting link, obtain the reference value of energy-storage system power output, as the switch triggering signal of DC/DC converter; Described energy-storage system comprises lithium battery energy storage battery system and super capacitor energy-storage system.

Such as Fig. 4, described step 2 may further comprise the steps:

Step 2-1: tuning controller is measured DC bus-bar voltage U in real time _DC, the state-of-charge of lithium battery and the terminal voltage of super capacitor, and determine the control model of DC/DC converter according to Monitoring Data;

Step 2-2: tuning controller is measured the load power P of the friendly type distributed power source of described electrical network in real time _lPower output P with intermittent renewable energy system _r, calculate the power shortage P of described mixed energy storage system _s, P _s=P _l-P _r, and extract P _sIn low frequency component P _{B_ref}, described P _{B_ref}Be the value and power reference of permanent power control mode lithium battery energy storage battery system, P _lBe the load power of distributed power source, P _rPower output for intermittent renewable energy system;

Step 2-3: when DC bus-bar voltage drops on zone 1, i.e. U ₀＜U _DC＜U ₁The time, DC/DC converter A is operated in and decides voltage mode control, and its reference voltage is got U _Ref1, the current amplitude limit value of current regulator and the power magnitude limit value of power control loop are got respectively I _Max1And P _Max1DC/DC converter B and DC/DC converter C do not work;

Wherein: U ₀The maximum that-DC bus-bar voltage allows;

U _DCThe real-time measurement values of-DC bus-bar voltage;

U _Ref1-DC bus-bar voltage dropped on regional 1 o'clock, the fixed voltage-controlled voltage reference value of DC/DC converter A, and its choosing value is positioned at zone 1, i.e. U ₀＜U _Ref1＜U ₁

I _Max1-DC/DC converter A current regulator allows the current maxima passed through;

P _Max1-DC/DC converter A power control loop allows the maximum power sent;

Step 2-4: when DC bus-bar voltage drops on zone 2, i.e. U ₂＜U _DC＜U ₁The time, DC/DC converter A is operated in the MPPT control model, and DC/DC converter B is operated in and decides voltage mode control, and its reference voltage is got U _Ref2, the current amplitude limit value of current regulator and the power magnitude limit value of power control loop are got respectively I _Max2And P _Max2DC/DC converter C is operated in the constant current discharge control model, and the reference voltage of its voltage control loop is got U _{Ref_ab}, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _{Sc_ref}And P _Max3In this process, the terminal voltage U of tuning controller Real-Time Monitoring super capacitor _UcIf detect U _Min＜U _Uc＜U _Max, change step 2-5 operation over to;

Wherein: U _Ref2-DC bus-bar voltage dropped on regional 2 o'clock, the fixed voltage-controlled voltage reference value of DC/DC converter B, and its choosing value is positioned at zone 2, i.e. U ₁＜U _Ref2＜U ₂

I _Max2-DC/DC converter B current regulator allows the current maxima passed through;

P _Max2-DC/DC converter B power control loop allows the maximum power sent;

U _{Ref_ab}The voltage reference value of DC/DC converter C voltage control loop;

I _{Sc_ref}The reference value of the super capacitor charging and discharging currents of-setting;

P _Max3-DC/DC converter C power control loop allows the maximum power sent;

U _UcThe terminal voltage of-super capacitor;

U _MinThe smallest end voltage that-super capacitor allows;

U _MaxThe maximum terminal voltage that super capacitor allows;

Step 2-5: when DC bus-bar voltage drops on zone 3, i.e. U ₃＜U _DC＜U ₂The time, DC/DC converter A is operated in the MPPT pattern, and DC/DC converter B is operated in permanent power control mode, and the voltage reference value of its voltage control loop is got U ' _Ref-ab, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _Max2And P _Max2DC/DC converter C is operated in and decides voltage mode control, and the reference voltage of its voltage control loop is got U _Ref3, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _Max3And P _Max3

Wherein:

U ' _Ref-abThe voltage reference value of-DC/DC converter B voltage control loop;

U _Ref3-DC bus-bar voltage dropped on regional 3 o'clock, the fixed voltage-controlled voltage reference value of DC/DC converter C, and its choosing value is positioned at zone 3, i.e. U ₃＜U _Ref3＜U ₂

I _Max3-DC/DC converter C current regulator allows the current maxima passed through;

Step 2-6: when DC bus-bar voltage drops on zone 4, i.e. U ₄＜U _DC＜U ₃The time, DC/DC converter A is operated in the MPPT pattern, and the DC/DC converter B of lithium battery system is operated in and decides voltage mode control, and the voltage reference value of its voltage control loop is got U _Ref4, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _Max2And P _Max2DC/DC converter C is operated in the constant current charge control model, and the reference voltage of its voltage control loop is got U _{Ref_ab}, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _{Sc_ref}And P _Max3, in this process, the terminal voltage U of tuning controller Real-Time Monitoring super capacitor _UcIf detect U _Min＜U _Uc＜U _Max, change step 2-5 operation over to;

Wherein:

U ₄The maximum U that-DC bus-bar voltage allows ₀＞U ₁＞U ₂＞U ₃＞U ₄

U _Ref4-DC bus-bar voltage dropped on regional 4 o'clock, the fixed voltage-controlled voltage reference value of DC/DC converter B, and its choosing value should drop in the zone 4, i.e. U ₄＜U _Ref4＜U ₃

Such as Fig. 5, AC DC/AC converter adopts the control of motor synchronizing voltage source, introduce simultaneously virtual impedance control and the control of double mode seamless switching, and to the normalized of above-mentioned control model, so that distributed power source is when incorporating the little electrical network of mesolow into, can with inverter type distributed power source or conventional synchronization motor-type distributed power source group net operation in parallel.

In the control of motor synchronizing voltage source, three-phase voltage and the electric current of the output of Real-time Collection DC/AC converter, according to instantaneous power theory, calculate active-power P and the reactive power Q of the output of DC/AC converter, adopt the control of motor synchronizing voltage source, calculate the reference frequency f of the virtual output voltage phasor of DC/AC converter _{Vir_ref}With reference amplitude V _{Vir_ref}:

$\left\{\begin{array}{c}{f}_{\mathrm{vir}-\mathrm{ref}}=f^{*}-m(P^{*}-P)\\ V_{\mathrm{vir}-\mathrm{ref}}=V^{*}-n(Q^{*}-Q)\end{array}\right.---(2-1)$

Wherein:

f _{Vir_ref}The reference frequency of the virtual output voltage phasor of-DC/AC converter;

V _{Vir_ref}The reference amplitude of the virtual output voltage phasor of-DC/AC converter;

f ^*The reference frequency of-mixed energy storage system rated voltage;

V ^*The reference amplitude of-mixed energy storage system rated voltage;

The sagging coefficient of m-meritorious/frequency droop control;

The sagging coefficient of n-REACTIVE POWER/VOLTAGE droop control;

P ^*-DC/AC converter is at f ^*The active power reference value of lower output;

Q ^*-DC/AC converter is at V ^*The reactive power reference qref of lower output;

The active power that P-the DC/AC converter sends;

The reactive power that Q-the DC/AC converter sends;

When distributed power source is in when being incorporated into the power networks pattern f ^*, V ^*For frequency and the magnitude of voltage of electrical network, when distributed power source is in independent operation mode, f ^*, V ^*For the reference value of setting, in the system of 380V, generally get 50Hz, 380V.

M and n through type (2-2) calculate:

$\left\{\begin{array}{c}m=\frac{f_{\min }-f^{*}}{P_{\max }-P^{*}}\\ n=\frac{V_{\min }-V^{*}}{Q_{\max }-Q^{*}}\end{array}\right.---(2-2)$

Wherein:

f _MinThe minimum operation frequency that-mixed energy storage system allows;

V _MinThe minimum operation voltage that-mixed energy storage system allows;

P _MaxThe maximum active power that-converter can be exported;

Q _MaxThe maximum reactive power that-converter can be exported;

In the virtual impedance control, (2-3) calculates according to formula

$\left\{\begin{array}{c}\stackrel{\&CenterDot;}{V_{\mathrm{vir}\_\mathrm{ref}}}=V_{\mathrm{vir}\_\mathrm{ref}}\&angle;{\mathrm{\&theta;}}_{\mathrm{vir}\_\mathrm{ref}}\\ {\mathrm{\&theta;}}_{\mathrm{vir}\_\mathrm{ref}}=2\mathrm{\&pi;}\underset{0}{\overset{t}{\&Integral;}}{f}_{\mathrm{vir}\_\mathrm{ref}}\mathrm{dt}\end{array}\right.---(2-3)$

$\stackrel{\&CenterDot;}{V_{\mathrm{ref}}}=\stackrel{\&CenterDot;}{V_{\mathrm{vir}\_\mathrm{ref}}}-\stackrel{\&CenterDot;}{I}{Z}_{\mathrm{vir}}---(2-4)$

In the formula:

The reference phasor of the virtual output voltage phasor of-DC/AC converter;

The reference phasor of-DC/AC converter output voltage phasor;

The electric current phasor that-DC/AC converter sends;

Z _Vir-virtual impedance.

In the double mode seamless switching control,

When distributed power source detected large electric network fault, the switch that is incorporated into the power networks disconnected, f ^*And V ^*Set-point change into set point under the independent operation mode by the frequency of line voltage and amplitude;

Fault clearance when large electrical network, distributed power source is converted to when being incorporated into the power networks pattern by independent operation mode, switch L1 and L2 among closed Fig. 5, start the motor synchronizing control of distributed power source, wait to satisfy when being incorporated into the power networks condition, the closure switch that is incorporated into the power networks is incorporated into the power networks distributed power source, is incorporated into the power networks to the impact of electrical network to reduce distributed power source.

In the motor synchronizing control, the frequency adjusted value of DC/AC converter output voltage phasor and range-adjusting value through type (2-5) calculate:

$\left\{\begin{array}{c}\mathrm{\&Delta;f}=({\mathrm{<figure-callout\; id="1"\; label="K\; p"\; filenames="HDA00002412193600022.png"\; state="\{\{state\}\}">K</figure-callout>}}_p+\frac{K_{i1}}{s})({\mathrm{\&theta;}}_g-{\mathrm{\&theta;}}_i)\\ \mathrm{\&Delta;U}=({\mathrm{<figure-callout\; id="2"\; label="K\; p"\; filenames="HDA00002412193600021.png"\; state="\{\{state\}\}">K</figure-callout>}}_p+\frac{K_{i2}}{s})(U_g-U_i)\end{array}\right.---(2-5)$

Wherein:

The frequency adjusted value of Δ f-DC/AC converter output voltage phasor;

The range-adjusting value of Δ U-DC/AC converter output voltage phasor;

K _P1The proportional control factor of-DC/AC frequency inverter Synchronization Control;

K _I1The integral adjustment coefficient of-DC/AC frequency inverter Synchronization Control;

K _P2-DC/AC converter voltage magnitude is followed the tracks of the proportional control factor in the control;

K _I2-DC/AC converter voltage magnitude is followed the tracks of the integral adjustment coefficient in the control;

θ _gThe phase angle of-line voltage phasor;

θ _iThe phase angle of the voltage phasor that-DC/AC converter sends;

U _gThe amplitude of-line voltage phasor;

U _iThe amplitude of the voltage phasor that-DC/AC converter sends.

Should be noted that at last: above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit, although with reference to above-described embodiment the present invention is had been described in detail, those of ordinary skill in the field are to be understood that: still can make amendment or be equal to replacement the specific embodiment of the present invention, and do not break away from any modification of spirit and scope of the invention or be equal to replacement, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (10)

1. control method based on the friendly type distributed power source of the electrical network of hybrid energy-storing is characterized in that: said method comprising the steps of:

Step 1: the topological structure of optimal design distributed power source;

Step 2: coordinate the control DC power-supply system by DC/DC convertor controls pattern normalization model;

Step 3: the electrical network adaptive control of AC DC/AC converter.

2. the control method of the friendly type distributed power source of the electrical network based on hybrid energy-storing according to claim 1, it is characterized in that: in the topological structure of the distributed power source of described step 1, intermittent renewable energy system, lithium battery energy storage battery system and super capacitor energy-storage system are in parallel with dc bus by DC/DC converter A, DC/DC converter B and DC/DC converter C respectively, consist of the DC power-supply system of distributed power source, this DC power-supply system is connected with AC system by AC DC/AC converter, forms distributed power source.

3. the control method of the friendly type distributed power source of the electrical network based on hybrid energy-storing according to claim 1, it is characterized in that: in the described step 2, the DC/DC converter comprises DC/DC converter A, DC/DC converter B and DC/DC converter C; The control model of DC/DC converter comprises decides voltage mode control, constant current control model and permanent power control mode; Choosing of power magnitude limit value by the instruction of voltage control loop reference power, current regulator current amplitude limit value and power control loop determined above-mentioned different control model; The constant current control model comprises constant current charge control model and constant current discharge control model.

4. the control method of the friendly type distributed power source of the electrical network based on hybrid energy-storing according to claim 1, it is characterized in that: in the described DC/DC convertor controls pattern normalization model, the difference of the reference value of busbar voltage and its measured value is regulated through PI, pass through again the current limit link, obtain the reference value of energy-storage system output current, the difference of energy-storage system output current reference value and its output current measured value is regulated through PI, and then by the power limiting link, obtain the reference value of energy-storage system power output, as the switch triggering signal of DC/DC converter; Described energy-storage system comprises lithium battery energy storage battery system and super capacitor energy-storage system.

5. the control method of the friendly type distributed power source of the electrical network based on hybrid energy-storing according to claim 1, it is characterized in that: described step 2 may further comprise the steps:

Step 2-1: tuning controller is measured DC bus-bar voltage U in real time _DC, the state-of-charge of lithium battery and the terminal voltage of super capacitor, and determine the control model of DC/DC converter according to Monitoring Data;

Step 2-2: tuning controller is measured the load power P of the friendly type distributed power source of described electrical network in real time _lPower output P with intermittent renewable energy system _r, calculate the power shortage P of described mixed energy storage system _s, P _s=P _l-P _r, and extract P _sIn low frequency component P _{B_ref}Described P _{B_ref}Be the value and power reference of permanent power control mode lithium battery energy storage battery system, P _lBe the load power of distributed power source, P _rPower output for intermittent renewable energy system;

Step 2-3: when DC bus-bar voltage drops on zone 1, i.e. U ₀＜U _DC＜U ₁The time, DC/DC converter A is operated in and decides voltage mode control, and its reference voltage is got U _Ref1, the current amplitude limit value of current regulator and the power magnitude limit value of power control loop are got respectively I _Max1And P _Max1DC/DC converter B and DC/DC converter C do not work;

Wherein: U ₀The maximum that-DC bus-bar voltage allows;

U _DCThe real-time measurement values of-DC bus-bar voltage;

U _Ref1-DC bus-bar voltage dropped on regional 1 o'clock, the fixed voltage-controlled voltage reference value of DC/DC converter A, and its choosing value is positioned at zone 1, i.e. U ₀＜U _Ref1＜U ₁

I _Max1-DC/DC converter A current regulator allows the current maxima passed through;

P _Max1-DC/DC converter A power control loop allows the maximum power sent;

Step 2-4: when DC bus-bar voltage drops on zone 2, i.e. U ₂＜U _DC＜U ₁The time, DC/DC converter A is operated in the MPPT control model, and DC/DC converter B is operated in and decides voltage mode control, and its reference voltage is got U _Ref2, the current amplitude limit value of current regulator and the power magnitude limit value of power control loop are got respectively I _Max2And P _Max2DC/DC converter C is operated in the constant current discharge control model, and the reference voltage of its voltage control loop is got U _{Ref_ab}, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _{Sc_ref}And P _Max3In this process, the terminal voltage U of tuning controller Real-Time Monitoring super capacitor _UcIf detect U _Min＜U _Uc＜U _Max, change step 2-5 operation over to;

Wherein: U _Ref2-DC bus-bar voltage dropped on regional 2 o'clock, the fixed voltage-controlled voltage reference value of DC/DC converter B, and its choosing value is positioned at zone 2, i.e. U ₁＜U _Ref2＜U ₂

I _Max2-DC/DC converter B current regulator allows the current maxima passed through;

P _Max2-DC/DC converter B power control loop allows the maximum power sent;

U _{Ref_ab}The voltage reference value of-DC/DC converter C voltage control loop;

I _{Sc_ref}The reference value of the super capacitor charging and discharging currents of-setting;

P _Max3-DC/DC converter C power control loop allows the maximum power sent;

U _UcThe terminal voltage of-super capacitor;

U _MinThe smallest end voltage that-super capacitor allows;

U _MaxThe maximum terminal voltage that-super capacitor allows;

Step 2-5: when DC bus-bar voltage drops on zone 3, i.e. U ₃＜U _DC＜U ₂The time, DC/DC converter A is operated in the MPPT pattern, and DC/DC converter B is operated in permanent power control mode, and the voltage reference value of its voltage control loop is got U ' _Ref-ab, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _Max2And P _Max2DC/DC converter C is operated in and decides voltage mode control, and the reference voltage of its voltage control loop is got U _Ref3, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _Max3And P _Max3

Wherein:

U ' _Ref-abThe voltage reference value of-DC/DC converter B voltage control loop;

U _Ref3-DC bus-bar voltage dropped on regional 3 o'clock, the fixed voltage-controlled voltage reference value of DC/DC converter C, and its choosing value is positioned at zone 3, i.e. U ₃＜U _Ref3＜U ₂

I _Max3-DC/DC converter C current regulator allows the current maxima passed through;

Step 2-6: when DC bus-bar voltage drops on zone 4, i.e. U ₄＜U _DC＜U ₃The time, DC/DC converter A is operated in the MPPT pattern, and the DC/DC converter B of lithium battery system is operated in and decides voltage mode control, and the voltage reference value of its voltage control loop is got U _Ref4, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _Max2And P _Max2DC/DC converter C is operated in the constant current charge control model, and the reference voltage of its voltage control loop is got U _{Ref_ab}, the amplitude limit value of current regulator and the amplitude limit value of power control loop are got respectively I _{Sc_ref}And P _Max3, in this process, the terminal voltage U of tuning controller Real-Time Monitoring super capacitor _UcIf detect U _Min＜U _Uc＜U _Max, change step 2-5 operation over to;

Wherein:

U ₄The maximum U that-DC bus-bar voltage allows ₀＞U ₁＞U ₂＞U ₃＞U ₄

U _Ref4-DC bus-bar voltage dropped on regional 4 o'clock, the fixed voltage-controlled voltage reference value of DC/DC converter B, and its choosing value should drop in the zone 4, i.e. U ₄＜U _Ref4＜U ₃

6. the control method of the friendly type distributed power source of the electrical network based on hybrid energy-storing according to claim 1, it is characterized in that: in the described step 3, AC DC/AC converter adopts the control of motor synchronizing voltage source, introduce simultaneously virtual impedance control and the control of double mode seamless switching, and to the normalized of above-mentioned control model, so that distributed power source is when incorporating the little electrical network of mesolow into, can with inverter type distributed power source or conventional synchronization motor-type distributed power source group net operation in parallel.

7. the control method of the friendly type distributed power source of the electrical network based on hybrid energy-storing according to claim 6, it is characterized in that: in the control of motor synchronizing voltage source, three-phase voltage and the electric current of the output of Real-time Collection DC/AC converter, according to instantaneous power theory, calculate active-power P and the reactive power Q of the output of DC/AC converter, adopt the control of motor synchronizing voltage source, calculate the reference frequency f of the virtual output voltage phasor of DC/AC converter _{Vir_ref}With reference amplitude V _{Vir_ref}:

Wherein:

f _{Vir_ref}The reference frequency of the virtual output voltage phasor of-DC/AC converter;

V _{Vir_ref}The reference amplitude of the virtual output voltage phasor of-DC/AC converter;

f ^*The reference frequency of-mixed energy storage system rated voltage;

V ^*The reference amplitude of-mixed energy storage system rated voltage;

The sagging coefficient of m-meritorious/frequency droop control;

The sagging coefficient of n-REACTIVE POWER/VOLTAGE droop control;

P ^*-DC/AC converter is at f ^*The active power reference value of lower output;

Q ^*-DC/AC converter is at V ^*The reactive power reference qref of lower output;

The active power that the P-DC/AC converter sends;

The reactive power that the Q-DC/AC converter sends;

M and n through type (2-2) calculate:

Wherein:

f _MinThe minimum operation frequency that-mixed energy storage system allows;

V _MinThe minimum operation voltage that-mixed energy storage system allows;

P _MaxThe maximum active power that-converter can be exported;

Q _MaxThe maximum reactive power that-converter can be exported.

8. the control method of the friendly type distributed power source of the electrical network based on hybrid energy-storing according to claim 6, it is characterized in that: in the virtual impedance control, (2-3) calculates according to formula

In the formula:

The reference phasor of the virtual output voltage phasor of-DC/AC converter;

The reference phasor of-DC/AC converter output voltage phasor;

The electric current phasor that-DC/AC converter sends;

Z _Vir-virtual impedance.

9. the control method of the friendly type distributed power source of the electrical network based on hybrid energy-storing according to claim 6 is characterized in that: in the double mode seamless switching control,

When distributed power source detected large electric network fault, the switch that is incorporated into the power networks disconnected, f ^*And V ^*Set-point change into set point under the independent operation mode by the frequency of line voltage and amplitude;

When the fault clearance of large electrical network, distributed power source is converted to when being incorporated into the power networks pattern by independent operation mode, starts the motor synchronizing control of distributed power source, wait to satisfy when being incorporated into the power networks condition, the closure switch that is incorporated into the power networks is incorporated into the power networks distributed power source, is incorporated into the power networks to the impact of electrical network to reduce distributed power source.

10. the control method of the friendly type distributed power source of the electrical network based on hybrid energy-storing according to claim 9, it is characterized in that: in the motor synchronizing control, the frequency adjusted value of DC/AC converter output voltage phasor and range-adjusting value through type (2-5) calculate:

Wherein:

The frequency adjusted value of Δ f-DC/AC converter output voltage phasor;

The range-adjusting value of Δ U-DC/AC converter output voltage phasor;

K _P1The proportional control factor of-DC/AC frequency inverter Synchronization Control;

K _I1The integral adjustment coefficient of-DC/AC frequency inverter Synchronization Control;

K _P2-DC/AC converter voltage magnitude is followed the tracks of the proportional control factor in the control;

K _I2-DC/AC converter voltage magnitude is followed the tracks of the integral adjustment coefficient in the control;

θ _gThe phase angle of-line voltage phasor;

θ _iThe phase angle of the voltage phasor that-DC/AC converter sends;

U _gThe amplitude of-line voltage phasor;

U _iThe amplitude of the voltage phasor that-DC/AC converter sends.

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