A grid-forming energy storage system ac-dc side coordinated control system and method

Abstract

The application discloses a grid-constructing type energy storage system AC-DC side coordinated control system and method, wherein the DC side of an energy storage AC converter is connected with the DC port of a battery stack, a capacitor is connected in parallel with the DC side of the energy storage converter and the battery stack; the AC side of the energy storage converter is connected with a grid-constructing type control system; the DC side of the energy storage AC converter is connected with a fixed DC bus voltage control system; the grid-constructing type control system is used for generating a modulation signal of the energy storage AC converter based on the voltage value and the current value collected at a PCC point; the fixed DC bus voltage control system is used for generating the modulation signal required by each battery cluster based on the bridge arm current reference value of each battery cluster calculated according to the voltage at both ends, the SOC state of all batteries in the plurality of battery clusters and the capacitor C dc The application realizes AC-DC side decoupling control, and improves the small disturbance stability and the large disturbance stability of the system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of AC / DC side coordinated control, and more particularly to an AC / DC side coordinated control system and method for grid-forming energy storage system. BACKGROUND

[0002] With the continuous improvement of new energy power generation penetration, the inertia of the power system is reduced, and the strength of the power grid is weakened, which has caused a series of problems including wide frequency oscillation, resonance overvoltage, etc. In order to improve the active support capability of new energy power generation equipment to the power grid, grid-forming energy storage system based on electrochemical energy storage will receive more and more attention and research. When the power grid is disturbed or fails, the grid-forming energy storage system not only has active support capability, but also has stronger weak power grid stable operation capability.

[0003] The document "Research on Control of Grid-Forming Parallel Energy Storage Inverter Based on Improved Virtual Synchronous Generator" proposes an improved grid-forming control strategy, which improves the SOC balancing problem of the energy storage system under the grid-forming control strategy. However, the SOC balancing strategy is realized on the AC side of the energy storage AC converter, which inevitably introduces the coupling between the AC / DC sides in control.

[0004] The document "Analysis and Damping of Low-Frequency Oscillation for DC-Link Voltage-Synchronized VSCs" proposes a grid-forming converter control strategy with DC bus voltage control. However, this strategy combines DC bus voltage control and grid-forming power synchronization control together, and is realized by the AC side of the AC converter, which directly introduces the coupling between the AC / DC sides in control.

[0005] However, whether it is a lithium ion battery energy storage system or a sodium ion battery energy storage system, the DC voltage change caused by the charging and discharging state process will have a certain impact on the stable operation of the AC side grid-forming energy storage AC converter. Especially for sodium ion batteries, compared with lithium ion batteries, they do not have a smooth discharge platform and are more sensitive to load changes, making the grid-forming control of the energy storage system based on sodium ion batteries have great defects. The DC side voltage change is more severe, which will inevitably adversely affect the stable operation of the AC side grid-forming energy storage AC converter.

[0006] Therefore, in the prior art, the unified DC bus voltage cannot be realized on the DC side, the AC side needs to assist in stabilizing the DC bus voltage, and the AC side controller needs to assist in balancing the DC side battery SOC, which leads to the coupling between the AC / DC sides in control, further leading to the stable operation problem of the entire energy storage system. SUMMARY

[0007] Therefore, the application aims to provide a grid-forming energy storage system AC / DC side coordinated control system and method, the DC side adopts fixed DC bus voltage control, the AC side adopts grid-forming control, the AC / DC side control of the grid-forming energy storage system is decoupled, and the operation stability of the energy storage system is improved.

[0008] To achieve the above object, the application provides the following technical scheme.

[0009] A grid-forming energy storage system AC / DC side coordinated control system comprises an energy storage converter, a battery stack, a capacitor C dc , a first inductor L g , and a second inductor L f .

[0010] The DC side of the energy storage converter is connected with the DC port of the battery stack, the capacitor C dc is connected in parallel with the DC side of the energy storage converter and the battery stack, and the battery stack is composed of a plurality of battery clusters connected in parallel.

[0011] The AC side of the energy storage converter is connected with the grid in sequence through the second inductor L f and the first inductor L g , and a PCC point is arranged between the second inductor L f and the first inductor L g .

[0012] The AC side of the energy storage converter is connected with a grid-forming control system, and the DC side of the energy storage converter is connected with a fixed DC bus voltage control system.

[0013] The grid-forming control system is used to generate a modulation signal V c of the energy storage converter based on the voltage value and the current value collected by the PCC point.

[0014] The fixed DC bus voltage control system is used to generate the modulation signal m1-m N required by each battery cluster based on the bridge arm current value i arm1 -i armN of each battery cluster, the SOC state SOC 11 -SOC MN of all batteries in the plurality of battery clusters, and the bridge arm current reference value i armref of each battery cluster calculated according to the voltage across the capacitor C dc .

[0015] Further, the grid-forming control system comprises a first voltage sensor, a first current sensor, a power calculation module, a power synchronization control module, a reactive power-voltage control module, and a voltage-current double-loop control module.

[0016] The first voltage sensor and the first current sensor are connected with the PCC point respectively;

[0017] The first voltage sensor and the first current sensor are connected with the power calculation module respectively; the power calculation module is connected with the power synchronization control module and the reactive-voltage control module respectively; the power synchronization control module and the reactive-voltage control module are connected with the voltage-current double loop control module;

[0018] The first voltage sensor is used for collecting the voltage information of the PCC point, and the first current sensor is used for collecting the current information of the PCC point;

[0019] The power calculation module is used for receiving the voltage information of the PCC point and the current information of the PCC point, and obtaining the active power P and the reactive power Q transmitted by the energy storage AC converter;

[0020] The power synchronization control module is used for obtaining the phase angle θ of the reference voltage according to the active power reference value P ref and the active power P transmitted by the energy storage AC converter;

[0021] The reactive-voltage control module is used for obtaining the amplitude E of the reference voltage according to the reactive power reference value Q ref and the reactive power Q transmitted by the energy storage AC converter;

[0022] The voltage-current double loop control module is used for generating the modulation signal V c of the energy storage converter according to the phase angle θ of the reference voltage and the amplitude E of the reference voltage.

[0023] Further, the direct current bus voltage control system comprises a second voltage sensor, a difference calculation module, a PI regulator, a current inner loop and an SOC balance control module.

[0024] The second voltage sensor is connected with the capacitor C dc , the difference calculation module is connected with the second voltage sensor, the difference calculation module is connected with the PI regulator, the PI regulator is connected with the current inner loop and the SOC balance control module, and the current inner loop and the SOC balance control module are connected with the circuit module in the battery stack.

[0025] The second voltage sensor is used for collecting the voltage value u dc across the capacitor C dc ;

[0026] The difference calculation module is used for comparing the voltage value u dc with the reference value U dcref to obtain a voltage comparison difference;

[0027] The PI regulator is used to compare the voltage difference with the reference value U. dcref Modulation is performed to obtain the bridge arm current reference value i. armref ;

[0028] The current inner loop and SOC balancing control module are based on the bridge arm current value i of each battery cluster. arm1 ~i armN State of Charge (SOC) of all batteries in several battery clusters 11 ~SOC MN And based on the bridge arm current reference value i armref The modulation signals m1 to m2 required to generate each battery cluster are generated. N .

[0029] This invention provides a coordinated control method for the AC / DC side of a grid-type energy storage system, the method comprising the following steps:

[0030] S1. Sample the voltage and current signals of the PCC point on the AC side of the energy storage converter to obtain the voltage and current values ​​of the PCC point respectively.

[0031] S2. Input the voltage and current values ​​at PCC point into the AC-side grid-type control system for data processing to obtain the modulation signal V of the energy storage AC unit. c ;

[0032] S3, the capacitor C on the DC side of the energy storage converter. dc The voltage signal is sampled to obtain the capacitance C. dc voltage value u dc ;

[0033] Based on the difference calculation module, the voltage value u dc Compared with reference value U dcref By comparing the values, the voltage difference is obtained.

[0034] The voltage difference is input to the PI regulator to obtain the reference value i of the bridge arm current for each cell cluster in the battery stack. armref ;

[0035] S4. Obtain the bridge arm current value i of each battery cluster in the battery stack. arm1 ~i armN and all battery SOC states 11 ~SOC MN ;

[0036] S5, set the bridge arm current reference value i armref Bridge arm current value i arm1 ~i armN and all battery SOC states 11 ~SOCMN The input to the current inner loop and SOC equalization control module, get each battery cluster required modulation signal m1~m N .

[0037] Further, the step S2 in the PCC point voltage value and the PCC point current value are input into the AC side network type control system for data processing, get the modulation signal V c , specifically:

[0038] The PCC point voltage and PCC point current are input into the power calculation module, respectively get the active power P and reactive power Q at the PCC point;

[0039] The active power P and the active power reference value P ref Input into the power synchronization control module, get the phase angle of the reference voltage θ;

[0040] The reactive power Q and the reactive power reference value Q ref Input into the reactive-voltage control module, get the amplitude of the reference voltage E;

[0041] The phase angle of the reference voltage θ and the amplitude of the reference voltage E are input into the voltage-current double loop control module, get the energy storage inverter modulation signal V c .

[0042] Further, the step S1 in the PCC point voltage signal and current signal of the AC side of the energy storage converter are sampled, respectively obtain the PCC point voltage value and the PCC point current value, specifically:

[0043] The first voltage sensor is used to collect the PCC point voltage signal;

[0044] The first current sensor is used to collect the PCC point current signal.

[0045] According to the specific embodiments provided by the application, the application first controls all the batteries as a whole from the topology, and then realizes the constant DC bus voltage and all battery SOC equalization control by the battery stack from the control strategy, and at the same time realizes the network control by the energy storage converter, thereby abandoning the control strategy of "energy storage converter realizing network control and DC bus voltage control" in the existing scheme, realizing the AC / DC side decoupling control, and improving the small disturbance stability and large disturbance stability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative effort based on the provided drawings.

[0047] The grid-connected energy storage system AC-DC side coordinated control system and method provided by the present application will be further described below in combination with the drawings.

[0048] Figure 1 The grid-connected energy storage system AC-DC side coordinated control system provided by the present application is shown in the overall structure diagram.

[0049] Figure 2 The grid-connected energy storage system AC-DC side coordinated control system provided by the present application is shown in the connection diagram of each battery cluster inside the battery stack.

[0050] In the figure: 1, power grid; 2, energy storage converter; 3, battery stack; 4, power calculation module; 5, power synchronization control module; 6, reactive power-voltage control module; 7, voltage-current double-loop control module; 8, PI regulator; 9, current inner loop and SOC balancing control module; 10, battery cluster. DETAILED DESCRIPTION

[0051] The specific embodiments of the present application will be further described in detail below in combination with the drawings and embodiments. The following embodiments are used to illustrate the present application, but not to limit the scope of the present application.

[0052] In order to better understand the purpose, structure and function of the present application, the present application will be further described in detail below in combination with the drawings.

[0053] As shown in Figure 1 , a grid-connected energy storage system AC-DC side coordinated control system comprises: an energy storage converter 2, a battery stack 3, a capacitor C dc , a first inductor L g , and a second inductor L f .

[0054] The DC side of the energy storage converter 2 is connected with the DC port of the battery stack 3, and the capacitor C dc is connected in parallel with the DC side of the energy storage converter 2 and the battery stack 3; as shown in Figure 2 , the battery stack 3 is composed of a plurality of battery clusters 10 connected in parallel;

[0055] The AC side of the energy storage converter 2 is connected with the power grid 1 through the second inductor L f and the first inductor L g in sequence; the second inductor Lf First inductor L g Set PCC points between them;

[0056] The AC side of the energy storage converter 2 is connected to the grid-type control system; the DC side of the energy storage AC converter 2 is connected to the constant DC bus voltage control system.

[0057] The network-type control system is used to generate a modulation signal V for the energy storage AC device 2 based on the voltage and current values ​​collected at the PCC point. c ;

[0058] The constant DC bus voltage control system is used to control the voltage based on the current value i of each battery cluster in the bridge arm. arm1 ~i armN The State of Charge (SOC) of all batteries in several battery clusters 10 11 ~SOC MN And according to the capacitance C dc The reference value i of the bridge arm current of each battery cluster 10 is obtained from the voltage calculation at both ends. armref The modulation signals m1 to m2 required to generate each battery cluster 10 are generated. N .

[0059] The network-type control system includes: a first voltage sensor, a first current sensor, a power calculation module 4, a power synchronization control module 5, a reactive power-voltage control module 6, and a voltage-current dual-loop control module;

[0060] The first voltage sensor and the first current sensor are respectively connected to the PCC point;

[0061] The first voltage sensor and the first current sensor are respectively connected to the power calculation module 4; the power calculation module 4 is respectively connected to the power synchronization control module 5 and the reactive power-voltage control module 6; the power synchronization control module 5 and the reactive power-voltage control module 6 are connected to the voltage-current dual-loop control module 7;

[0062] The first voltage sensor is used to collect voltage information at the PCC point, and the first current sensor is used to collect current information at the PCC point.

[0063] The power calculation module 4 is used to receive the voltage information and current information of the PCC point, and calculate the active power P and reactive power Q transmitted by the energy storage AC device 2.

[0064] The power synchronization control module 5 is used to control the active power reference value P transmitted by the energy storage AC device 2. ref The phase angle θ of the reference voltage is obtained from the active power P;

[0065] The reactive-voltage control module 6 is configured to obtain the amplitude E of the reference voltage according to the reactive power reference value Q ref and the reactive power Q.

[0066] The voltage-current double-loop control module 7 is configured to generate the modulation signal V c of the energy storage converter according to the phase angle θ of the reference voltage and the amplitude E of the reference voltage.

[0067] The direct current bus voltage control system comprises a second voltage sensor, a difference calculation module, a PI regulator 8, a current inner loop and an SOC balancing control module 9.

[0068] The second voltage sensor is connected with the capacitor C dc , the difference calculation module is connected with the second voltage sensor, the difference calculation module is connected with the PI regulator 8, the PI regulator 8 is connected with the current inner loop and the SOC balancing control module 9, and the current inner loop and the SOC balancing control module 9 are connected with the circuit modules in the battery stack.

[0069] The second voltage sensor is configured to collect the voltage value u dc across the capacitor C dc .

[0070] The difference calculation module is configured to compare the voltage value u dc with the reference value U dcref to obtain a voltage comparison difference.

[0071] The PI regulator 8 is configured to modulate the voltage comparison difference and the reference value U dcref to obtain the bridge arm current reference value i armref .

[0072] The current inner loop and the SOC balancing control module 9 generate the required modulation signals m1-m N of each battery cluster 10 based on the bridge arm current values i arm1 ~i armN of each battery cluster, the SOC states SOC 11 ~SOC MN of all the battery clusters 10 and the bridge arm current reference value i armref .

[0073] It should be noted that: first, all the battery SOC states SOC 11 ~SOC MN are sorted in descending order, and then the positive and negative values of the bridge arm current values of each battery cluster are measured by the second current sensor to determine the charging and discharging states of each battery cluster (as shown in the attached drawings). Figure 1As shown, when the bridge arm current is greater than 0, it is determined to be a discharge state; when the bridge arm current is less than 0, it is determined to be a charging state), next, the bridge arm current reference value i armref The bridge arm current value i arm1 ~i armN , the difference value is respectively passed through a proportional-integral regulator (PI regulator) to obtain a respective cluster voltage command value, and the on-off module number n k (k=1,…,N) is obtained from the voltage command value, finally, according to the charging and discharging state of each battery cluster, the SOC sorting result and the on-off module number n k , the modulation signal required by each battery cluster is determined, and then according to the modulation signal, it is determined whether to put in or cut off the battery PACK in each battery cluster; when the battery cluster is in a charging state, put in Floor(n k ) battery PACK with the smallest SOC, when the battery cluster is in a discharging state, put in Floor(n k ) battery PACK with the largest SOC.

[0074] The application provides a kind of AC / DC side coordination control method of network construction type energy storage system, the method comprises the following steps:

[0075] S1, the voltage signal and current signal of the PCC point of the AC side of energy storage converter 2 are sampled, and the voltage value of the PCC point and the current value of the PCC point are obtained respectively;

[0076] S2, the voltage value of the PCC point and the current value of the PCC point are input into the AC side network construction type control system for data processing, and the modulation signal V c of energy storage AC converter 2 is obtained;

[0077] S3, the voltage signal of the capacitor C dc of the DC side of energy storage converter 2 is sampled, and the voltage value u dc of the capacitor C dc is obtained;

[0078] The voltage value u dc and the reference value U dcref are compared based on the difference calculation module, and the voltage comparison difference is obtained;

[0079] The voltage comparison difference is input into PI regulator 8, and the bridge arm current reference value i armref of each battery cluster 10 in battery stack 3 is obtained;

[0080] S4, the bridge arm current value i arm1 ~i armN of each battery cluster 10 in battery stack 3 and all battery SOC states SOC 11 ~SOC MN;

[0081] It should be noted that: in the control strategy, the DC capacitor C dc The voltage u dc Is responsible for the control of the battery stack BS. First, the measured DC bus voltage u dc With the reference value U dcref Comparison, the difference after the action of PI regulator generates bridge arm current reference value i armref ; Then, the bridge arm current i arm1 ~i armN Of each battery cluster and the SOC state SOC 11 ~SOC MN Of all the batteries are sent to the "current inner loop and equalization control link", while completing the current closed loop control and SOC equalization control, finally generating the modulation signal m1~m N Required by each battery cluster.

[0082] S5, the bridge arm current reference value i armref , the bridge arm current value i arm1 ~i armN And all the SOC state SOC 11 ~SOC MN Of all the batteries are input into the current inner loop and SOC equalization control module 9, to get the modulation signal m1~m N Required by each battery cluster.

[0083] It should be noted that: the application is based on the decoupling control of the DC side of the network type energy storage system based on the topology of "battery-battery cluster-battery stack", which unifies the SOC equalization in the battery cluster, the SOC equalization between the battery clusters and the constant DC bus voltage in the DC side for coordinated control, realizing the decoupling of the network type control with the AC side energy storage converter.

[0084] The voltage value of the PCC point and the current value of the PCC point in step S2 are input into the AC side network type control system for data processing to obtain the modulation signal V c Of the energy storage AC converter, specifically:

[0085] The voltage of the PCC point and the current of the PCC point are input into the power calculation module 4 to obtain the active power P and the reactive power Q at the PCC point, respectively;

[0086] The active power P and the active power reference value P ref Are input into the power synchronization control module 5 to obtain the phase angle θ of the reference voltage;

[0087] The reactive power Q and the reactive power reference value Q ref Are input into the reactive-voltage control module 6 to obtain the amplitude E of the reference voltage;

[0088] The phase angle θ of the reference voltage and the amplitude E of the reference voltage are input into the voltage-current double loop control module 7 to obtain the energy storage AC converter modulation signal V c .

[0089] In the step S1, the voltage signal and the current signal of the PCC point on the AC side of the energy storage converter are sampled to obtain the voltage value of the PCC point and the current value of the PCC point, respectively, and specifically:

[0090] The voltage signal of the PCC point is collected by using the first voltage sensor;

[0091] The current signal of the PCC point is collected by using the first current sensor.

[0092] It should be noted that: the attached Figure 1 The provided topology of "battery-battery cluster-battery stack" can uniformly control a large number of and dispersed batteries as a whole, and the corresponding control strategy is shown in the attached Figure 1 The AC side energy storage converter adopts a general network-forming control strategy, including outer loop control and inner loop control. The "power calculation" unit in the outer loop control can calculate the active power P and the reactive power Q of the PCC point according to the voltage v abc and the current i abc measured at the PCC point. The outer loop control further includes a "power synchronization control" loop composed of the active power reference value P ref and the active power measurement value P of the PCC point, and a "reactive-voltage control" loop composed of the reactive power reference value Q ref and the reactive power measurement value Q of the PCC point. The "power synchronization" loop generates the phase angle θ of the reference voltage, and the "reactive-voltage control" loop generates the amplitude E of the reference voltage. E and θ are sent as reference instructions to the inner loop "voltage-current double loop control" to generate the energy storage converter modulation signal V c .

[0093] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A grid-forming energy storage system AC / DC side coordinated control system, characterized in that, Comprise: energy storage converter (2), battery stack (3), capacitor , first inductor , second inductor ; The direct current side of the energy storage converter (2) is connected with the direct current port of the battery stack (3), and the capacitor is connected in parallel with the direct current side of the energy storage converter (2) and the battery stack (3); the battery stack (3) is composed of a plurality of battery clusters (10) in parallel. The AC side of the energy storage converter (2) is sequentially connected to the second inductor. First Inductor Connected to the power grid (1); the second inductor First Inductor Between settings PCC point; The AC side of the energy storage converter (2) is connected with a grid-forming control system; the DC side of the energy storage converter (2) is connected with a fixed DC bus voltage control system; The network construction type control system is used for generating a modulation signal of the energy storage converter (2) based on PCC the voltage value and the current value collected by the point ; The direct current bus voltage control system is used for obtaining the bridge arm current reference value of each battery cluster (10) based on the bridge arm current value of each battery cluster (10) i arm1 ~i armN All batteries in several battery clusters (10) SOC State SOC 11 ~SOC MN And the bridge arm current reference value of each battery cluster (10) calculated according to the voltage across the capacitor i armref Generating the modulation signal required by each battery cluster (10) m 1 ~m N ;​ Wherein The grid-forming control system comprises a first voltage sensor, a first current sensor, a power calculation module (4), a power synchronization control module (5), a reactive power-voltage control module (6) and a voltage-current double-loop control module; The first voltage sensor and the first current sensor are respectively connected with the PCC point; The first voltage sensor and the first current sensor are respectively connected with the power calculation module (4); the power calculation module (4) is respectively connected with the power synchronization control module (5) and the reactive power-voltage control module (6); the power synchronization control module (5) and the reactive power-voltage control module (6) are connected with the voltage-current double-loop control module (7); The first voltage sensor is used for collecting voltage information of the PCC point, and the first current sensor is used for collecting current information of the PCC point; The power calculation module (4) is configured to receive voltage information of the PCC point and current information of the PCC point, and obtain calculated active power P and reactive power Q transmitted by the energy storage converter (2) Q ; The power synchronization control module (5) is configured to obtain a phase angle of a reference voltage according to an active power reference value transmitted by the energy storage converter (2) and an active power P Theta ;​ The reactive-voltage control module (6) is configured to determine a reference voltage value (Uref) in dependence on the reactive power reference value (Qref) and the voltage value (U) of the AC voltage (UAC) at the point of coupling (5) to the power grid (1). Q ref and the reactive power Q to obtain a magnitude of the reference voltage E； The voltage-current double loop control module (7) is configured to generate a modulation signal of the energy storage converter according to a phase angle of the reference voltage and a magnitude of the reference voltage E， V c ;​ The direct current bus voltage control system comprises a second voltage sensor, a difference calculation module, PI a regulator (8), a current inner loop and SOC a balance control module (9). The second voltage sensor is connected with a capacitor The difference calculation module is connected with the second voltage sensor; the difference calculation module is connected with PI The regulator (8); the PI The regulator (8) is connected with a current inner loop and SOC The equalization control module (9) is connected with the current inner loop and SOC The equalization control module (9) is connected with a circuit module in the battery stack; The second voltage sensor is used to collect the capacitance The voltage value at both ends u dc ; The difference calculation module is configured to compare the voltage value u dc with the reference value U dcref to obtain a voltage comparison difference. The PI regulator (8) is used to regulate the voltage comparison difference and reference value U dcref The bridge arm current reference value is obtained by modulating i armref ; The current inner loop and SOC The equalization control module (9) is based on the bridge arm current value of each battery cluster i arm1 ~i armN All batteries in several battery clusters (10) SOC State SOC 11 ~SOC MN And according to the bridge arm current reference value i armref Generate the modulation signal required for each battery cluster (10) m 1 ~m N .

2. A method for coordinated control of AC and DC sides of a grid-forming energy storage system, applied to the coordinated control system of AC and DC sides of a grid-forming energy storage system according to claim 1, characterized in that, Comprise the following steps: S1, for the AC side of the energy storage converter (2) PCC The voltage and current signals at the point are sampled to obtain... PCC The voltage value at the point and PCC The current value at the point; S2, will PCC The voltage value and PCC The voltage value and V c ; S3, sampling the voltage signal of the capacitor of the direct current side of the energy storage converter (2), obtaining the voltage value of the capacitor u dc ;​​ The voltage value is calculated based on a difference calculation module u dc compared with a reference value U dcref to obtain a voltage comparison difference The voltage comparison difference value is input to PI In the regulator (8), the bridge arm current reference value where each battery cluster (10) in the battery stack (3) is located is obtained i armref ; S4, obtaining a bridge arm current value of each battery cluster (10) in the battery stack (3) i arm1 ~i armN and all batteries SOC status SOC 11 ~ SOC MN ; S5, the bridge arm current reference value i armref , the bridge arm current value i arm1 ~i armN and all batteries SOC status SOC 11 ~SOC MN input to the current inner loop and SOC equalization control module (9), get the modulation signal required by each battery cluster (10) m 1 ~m N .

3. The network-configuration energy storage system AC / DC side coordinated control method of claim 2, wherein, The voltage value of the point and the current value of the point are input into the alternating current side network configuration type control system respectively for data processing to obtain the modulation signal of the energy storage converter PCC The voltage value of the point and the current value of the point are input into the alternating current side network configuration type control system respectively for data processing to obtain the modulation signal of the energy storage converter PCC The voltage value of the point and the current value of the point are input into the alternating current side network configuration type control system respectively for data processing to obtain the modulation signal of the energy storage converter V c , Specifically: The voltage and current of the point are input into the power calculation module (4) to obtain the active power and reactive power at the point, respectively. PCC PCC PCC P Q ;​​​​ active power P with the active power reference value P ref the phase angle of the reference voltage Theta ; reactive power Q and the reference value for the reactive power Q ref is input into the reactive-voltage control module (6) to obtain the magnitude of the reference voltage E ; The phase angle of the reference voltage Theta and The amplitude of the reference voltage E Input into the voltage-current double-loop control module (7) to obtain the energy storage converter modulation signal V c .

4. The network-configuration energy storage system AC / DC side coordinated control method of claim 2, wherein, In step S1, the AC side of the energy storage converter... PCC The voltage and current signals at the point are sampled to obtain... PCC The voltage value at the point and PCC The current value at the point is as follows: Using the first voltage sensor to collect PCC The voltage signal at the point; Data collected using the first current sensor PCC The current signal at the point.

Images