CN-122001240-A - Current equalizing control and circulation suppressing method for inverter

CN122001240ACN 122001240 ACN122001240 ACN 122001240ACN-122001240-A

Abstract

The disclosure relates to an inverter current sharing control and circulation suppression method, an inverter current sharing control and circulation suppression device, electronic equipment and a storage medium. The method comprises the steps of calculating circulation currents of a D axis, a Q axis and a Z axis of each inverter, performing droop control on the inverters based on the D axis current and the Q axis current, performing filtering adjustment control on circulation to generate a D axis voltage amplitude reference value and a reference voltage phase, performing control adjustment on Z axis circulation to obtain a Z axis voltage amplitude adjustment value, generating a Z axis voltage reference value, and performing closed-loop control according to the D axis voltage amplitude reference value, the reference voltage phase and the Z axis voltage reference value to achieve parallel operation current sharing control and circulation suppression of the inverters. The parallel operation current sharing control method solves the problem that parallel operation current sharing dynamic response is slower, can conduct current sharing control in real time, improves current sharing dynamic response speed, can greatly improve parallel operation current sharing degree, can greatly reduce parallel operation circulation, reduces parallel operation no-load light-load circulation, and improves reliability of a parallel operation system.

Inventors

XU SHIMIN
MENG TIAN
WU QIANFENG
LIU YEYONG
JI JINHU

Assignees

北京机械设备研究所

Dates

Publication Date: 20260508
Application Date: 20251218

Claims (10)

1. An inverter current sharing control and circulation suppression method, which is characterized by comprising the following steps: calculating average currents of a D axis, a Q axis and a Z axis of each inverter, and obtaining circulating currents of the D axis, the Q axis and the Z axis based on the calculated average currents and currents of the D axis, the Q axis and the Z axis of the inverter; Performing droop control on the inverter based on the D-axis current and the Q-axis current, performing filtering adjustment control on the inverter based on the D-axis circulation current and the Q-axis circulation current, respectively calculating a D-axis voltage amplitude droop control value and a phase droop value, a D-axis voltage circulation adjustment value and a phase circulation adjustment value, and generating a D-axis voltage amplitude reference value and a reference voltage phase; the Z-axis voltage amplitude adjustment value is obtained by controlling and adjusting the Z-axis current, and a Z-axis voltage reference value is generated; And performing closed-loop control according to the D-axis voltage amplitude reference value, the reference voltage phase and the Z-axis voltage reference value to realize parallel operation current sharing control and circulation suppression of the inverter.
2. The method of claim 1, wherein the method further comprises: Calculating average currents of a D axis, a Q axis and a Z axis of each inverter; and calculating the difference value between the low-pass filtered value of the D-axis, Q-axis and Z-axis currents of each inverter and the average current to obtain the circulating current of the D-axis, Q-axis and Z-axis currents.
3. The method of claim 1, wherein the method further comprises: Calculating a D-axis voltage magnitude droop value according to a formula VrefDrop = Kvref (a Dcur +b Qcur), wherein VrefDrop is the D-axis voltage droop value, kvref is a voltage magnitude droop coefficient calculated according to inverter power, and a and b are D-axis current and Q-axis current coefficients; The D-axis voltage phase sag is calculated according to the formula ThetaDrop = Ktheta (c Dcur +d Qcur), thetaDrop is the voltage phase sag, ktheta is the phase sag coefficient, and c and D are the D-axis current and Q-axis current coefficients.
4. A method as claimed in claim 3, wherein the method further comprises: Calculating a D-axis voltage amplitude circulation regulating input quantity according to a formula VrefCir =a× DcurAvg +b× QcurAvg, wherein VrefCir is the D-axis voltage amplitude circulation regulating input quantity, DCurAvg is the D-axis average current of all inverters, QCurAvg is the Q-axis average current of all inverters, and a and b are the D-axis current and the Q-axis current coefficient; Calculating a D-axis voltage phase circulation regulating input quantity according to a formula ThetaCir =c, dcurAvg +d, qcurAvg, wherein ThetaCir is the D-axis voltage phase circulation regulating input quantity, DCurAvg is the D-axis average current of all inverters, QCurAvg is the Q-axis average current of all inverters, and c and D are the D-axis current and the Q-axis current coefficient.
5. The method of claim 4, wherein the method further comprises: When the output impedance characteristic is a resistive load, a=1, b=0, c=0, d=1; When the output impedance characteristic is an inductive load, a=0, b=1, c=1, d=0; when the output impedance characteristic is a resistive load, a=1, b= -1, c=1, d=1.
6. The method of claim 5, wherein the method further comprises: Calculating a Z-axis voltage amplitude circulation adjustment amount according to a formula ZvrefCir = ZCurCir, wherein ZvrefCir is the Z-axis voltage amplitude circulation adjustment amount, and ZCurCir is the Z-axis current value; Calculating a D-axis voltage amplitude reference value according to a formula Vref=vtarget-VrefDrop-VREFCIRREG, wherein Vref is the D-axis voltage amplitude reference value, vtarget is an inverter target control voltage value, and VREFCIRREG is a D-axis voltage amplitude circulation regulating quantity regulated by a filter; calculating a voltage phase value according to the formula theta= ThetaPLL-ThetaDrop-THETACIRREG, wherein Theta is the voltage phase value and ThetaPLL is the phase lock phase of each inverter; and calculating a Z-axis voltage amplitude reference value according to a formula ZVref =0-ZVrefCirReg, wherein ZVref is the Z-axis voltage amplitude reference value, and ZVrefCirReg is the Z-axis voltage amplitude circulation regulating quantity regulated by a filter.
7. The method of claim 6, wherein the method further comprises: Giving the generated D-axis voltage amplitude reference value as D-axis input voltage, giving the generated Z-axis voltage amplitude reference value as Z-axis input voltage, and carrying out closed-loop control by taking the generated voltage phase as SPWM-transmitted front coordinate axis transformation reference angle to realize parallel operation current sharing control and circulation suppression of the inverter.
8. An inverter current sharing control and circulation suppression device, characterized in that the device comprises: The circulating current calculation module is used for calculating average currents of the D axis, the Q axis and the Z axis of each inverter, and obtaining circulating currents of the D axis, the Q axis and the Z axis based on the calculated average currents and currents of the D axis, the Q axis and the Z axis of the inverter; The D-axis reference value calculation module is used for performing droop control on the inverter based on the D-axis current and the Q-axis current, performing filtering adjustment control on the inverter based on the D-axis circulation and the Q-axis circulation, respectively calculating a D-axis voltage amplitude droop control value and a phase droop value, a D-axis voltage circulation adjustment value and a phase circulation adjustment value, and generating a D-axis voltage amplitude reference value and a reference voltage phase; the Z-axis reference value calculation module is used for controlling and adjusting the Z-axis ring flow to obtain a Z-axis voltage amplitude value and generate a Z-axis voltage reference value; And the parallel operation current sharing control module is used for performing closed-loop control according to the D-axis voltage amplitude reference value, the reference voltage phase and the Z-axis voltage reference value to realize parallel operation current sharing control and circulation suppression of the inverter.
9. An electronic device, comprising Processor, and A memory having stored thereon computer readable instructions which, when executed by the processor, implement the method according to any of claims 1 to 7.
10. A computer-readable storage medium, characterized in that a computer program is stored thereon, which computer program, when being executed by a processor, implements the method according to any of claims 1 to 7.

Description

Current equalizing control and circulation suppressing method for inverter Technical Field The disclosure relates to the technical field of inverters, and in particular relates to an inverter current sharing control and circulation suppression method, an inverter current sharing control and circulation suppression device, electronic equipment and a computer readable storage medium. Background Inverter parallel operation technology is one of core solutions for improving the capacity, reliability and flexibility of a power supply system. In the key fields of photovoltaic power generation, PCS, UPS and the like, a plurality of inverter units are combined in parallel, so that power expansion, redundancy backup and system reliability can be realized. In actual engineering, due to inherent factors such as element parameter differences, clock deviations of control chips, and inconsistent line impedance of each inverter module, circulating currents which do not flow through loads and circulate only among the modules are generated among the parallel inverters. The circulation not only increases the extra loss of the system and reduces the efficiency, but also causes distortion of current waveform, aggravates the electric stress of a switching device, even causes oscillation of the system, and causes module damage or system breakdown when serious. Therefore, how to effectively inhibit the circulation and realize accurate current sharing control is always a core difficulty in the parallel technology of the inverter. At present, the parallel operation of the inverter mostly adopts centralized control, master-slave control and droop control. The centralized control method is characterized in that a central controller is arranged, state information of all inverters is collected, and control instructions are sent to all units after calculation. The method has high control precision, but the central controller becomes a single point of failure, thereby reducing the reliability of the system and having slow dynamic influence. One inverter is designated as a master machine and is responsible for stabilizing the system voltage and frequency, and the other slaves track the master machine instruction or regulate the output current to equally divide the load. The mode has good current sharing effect, but the host computer needs to perform master-slave switching when in fault, the control logic is complex, and the dynamic response is slower. The droop control realizes parallel operation current sharing through frequency-active droop (f-P droop) and voltage-reactive droop (V-Q droop), the method can realize multi-machine parallel power distribution without a communication link, the reliability is high, but the accuracy of the power distribution is influenced by line impedance mismatch, the current sharing degree is lower, and the dynamic response is slower. In summary, the current parallel operation technology mainly has the problems that ① has conflict between reliability and current sharing degree, centralized control and master-slave control are realized, and the current sharing precision is higher, but the reliability is lower. The sagging control has higher reliability but lower average fluidity, and ② parallel operation has slower dynamic response to current sharing. Accordingly, there is a need for one or more approaches to address the above-described problems. It should be noted that the information disclosed in the above background section is only for enhancing understanding of the background of the present disclosure and thus may include information that does not constitute prior art known to those of ordinary skill in the art. Disclosure of Invention It is an object of the present disclosure to provide an inverter current sharing control and circulation suppression method, apparatus, electronic device, and computer-readable storage medium, which overcome, at least in part, one or more of the problems due to the limitations and disadvantages of the related art. According to one aspect of the present disclosure, there is provided an inverter current sharing control and circulation suppression method, including: calculating average currents of a D axis, a Q axis and a Z axis of each inverter, and obtaining circulating currents of the D axis, the Q axis and the Z axis based on the calculated average currents and currents of the D axis, the Q axis and the Z axis of the inverter; Performing droop control on the inverter based on the D-axis current and the Q-axis current, performing filtering adjustment control on the inverter based on the D-axis circulation current and the Q-axis circulation current, respectively calculating a D-axis voltage amplitude droop control value and a phase droop value, a D-axis voltage circulation adjustment value and a phase circulation adjustment value, and generating a D-axis voltage amplitude reference value and a reference voltage phase; the Z-axis voltage amplitude adjustment value is obtained