A reactive power sharing control system and method based on virtual synchronous machine parallel system

Abstract

The present invention discloses a reactive power sharing control system and method based on a virtual synchronous machine parallel system, wherein the reactive power sharing control system includes a current acquisition module, a voltage acquisition module, a power calculation module, a voltage rated amplitude correction module, a frequency-active power droop control and adjustment module, a virtual moment of inertia module, an inverter phase generation module, a voltage reference signal generation module, an amplitude detection module, a voltage-reactive power droop control and adjustment module, an integral adjustment module, a voltage reference signal generation module, a current loop reference signal generation module, a current loop adjustment module, a pulse width modulation module and a photoelectric conversion drive module; wherein the reactive power sharing control method is realized by the reactive power sharing control system. The present invention solves the problem of uneven reactive power sharing between inverters in the virtual synchronous machine parallel system and improves the safety of the virtual synchronous machine parallel system.

Description

Technical Field

[0001] The invention relates to a reactive power sharing control system and method based on a virtual synchronous machine parallel system, belonging to the technical field of virtual synchronous machine parallel safety control. Background Art

[0002] With the rapid development of the national economy, people's demand for electricity is increasing, the scale of the power grid and the capacity of long-distance power transmission are growing. In order to save investment and improve the safety and flexibility of the power generation system, distributed power generation systems came into being.

[0003] With the rapid development of distributed power generation, the requirements for the capacity, performance, and scalability of distributed power generation systems are becoming increasingly higher. As the core power generation equipment in distributed power generation systems, the inverter power supply is bound to develop from centralized power supply to distributed parallel power supply. At the same time, the inverter parallel technology is the basis for distributed power generation systems to achieve high reliability, high redundancy, high capacity, and high scalability, and it is also the key to the stable operation of distributed power generation systems.

[0004] However, when multiple inverters are connected in parallel to supply power to the load, if the impedance of the lines connecting the inverters is inconsistent, the distributed parallel scheme based on the traditional droop control strategy is difficult to achieve equal distribution of load reactive power among the inverters in the parallel system. In severe cases, it will cause significant current imbalance among the virtual synchronous machines, and the entire parallel system will not be able to work normally, thereby endangering the reliability of the inverter parallel system.

[0005] Therefore, those skilled in the art are in urgent need of developing a control system and method that can evenly distribute reactive power within a virtual synchronous machine. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a reactive power sharing control system and method based on a virtual synchronous machine parallel system. The present invention solves the problem of uneven reactive power distribution between inverters in the virtual synchronous machine parallel system and improves the safety of the virtual synchronous machine parallel system.

[0007] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0008] On the one hand, the present application provides a reactive power sharing control system based on a virtual synchronous machine parallel system, the virtual synchronous machine parallel system includes a plurality of parallel three-phase inverter main circuits including input power and load, each three-phase inverter main circuit is connected to a corresponding reactive power sharing control system, each reactive power sharing control system includes a current acquisition module, a voltage acquisition module, a power calculation module, a voltage rated amplitude correction module, a frequency-active power droop control and adjustment module, a virtual moment of inertia module, an inverter phase generation module, a voltage reference signal generation module, an amplitude detection module, a voltage-reactive power droop control and adjustment module, an integral adjustment module, a voltage reference signal generation module, a current loop reference signal generation module, a current loop adjustment module, a pulse width modulation module and a photoelectric conversion drive module;

[0009] The current acquisition module acquires the current signal of the main circuit of the three-phase inverter, and the voltage acquisition module acquires the output voltage signal of the three-phase inverter;

[0010] The output terminal I of the current acquisition module is connected to the power calculation module, and the output terminal II is connected to the current loop regulation module;

[0011] The first output end of the voltage acquisition module is connected to the power calculation module;

[0012] The two output ends of the power calculation module are respectively connected to the input end of the voltage rated amplitude correction module and the first input end of the frequency-active power droop control adjustment module, wherein the output end of the voltage rated amplitude correction module is connected to the second input end of the frequency-reactive power droop control adjustment module;

[0013] The output end of the frequency-active power droop control and adjustment module is connected to the virtual moment of inertia module, the inverter phase generation module and the voltage reference signal generation module in sequence, wherein the output end of the virtual moment of inertia module is connected to the third input end of the frequency-active power droop control and adjustment module;

[0014] The second output end of the voltage acquisition module is connected to the amplitude detection module, the voltage-reactive power droop control and regulation module, the integral regulation module, the voltage reference signal generation module, the current loop reference signal generation module, the current loop regulation module, the pulse width modulation module and the photoelectric conversion drive module in sequence, wherein the third output end of the voltage acquisition module is connected to the input end of the current loop reference signal generation module, and the fourth output end of the voltage acquisition module is connected to the input end of the current loop regulation module;

[0015] The photoelectric conversion drive module is communicatively connected to the power switch tube of the three-phase inverter main circuit, and outputs a power switch tube on or off signal according to the duty cycle signal output by the pulse width modulation module, thereby driving the power switch tube to be on or off.

[0016] On the other hand, the present application provides a reactive power sharing control method based on a virtual synchronous machine parallel system, which is implemented based on the reactive power sharing control system based on the virtual synchronous machine parallel system, and includes the following steps:

[0017] The current acquisition module acquires the current signal and sends it to the power calculation module and the current loop regulation module;

[0018] The voltage acquisition module acquires the voltage signal and sends it to the power calculation module, the voltage amplitude detection module, the current loop reference signal generation module and the current loop adjustment module;

[0019] The power calculation module calculates the active power signal and the reactive power signal according to the received current signal and voltage signal, and sends them to the voltage rated amplitude correction module and the frequency-active power droop control and adjustment module respectively. The frequency-active power droop control and adjustment module sends the received reactive power signal to the virtual rotation inertia module;

[0020] The voltage rated amplitude correction module calculates the voltage rated amplitude correction value signal according to the received reactive power signal and sends it to the voltage-reactive power droop control and adjustment module;

[0021] The voltage amplitude detection module calculates the output voltage amplitude signal according to the received voltage signal and sends it to the voltage-reactive power droop control and regulation module;

[0022] The virtual moment of inertia module calculates the voltage reference signal angular frequency information signal according to the received active power signal and sends it to the voltage-reactive power droop control and regulation module and the inverter phase generation module;

[0023] The voltage-reactive power droop control and regulation module calculates the reactive power droop given value signal according to the received voltage amplitude signal and the voltage rated amplitude correction value signal, calculates the active power droop given value signal according to the received voltage reference signal angular frequency information signal, and sends the reactive power droop given value signal and the active power droop given value signal to the integral regulation module;

[0024] The integral regulation module calculates the amplitude information signal of the voltage reference signal according to the received reactive power droop given value signal and the active power droop given value signal and sends the calculated amplitude information signal to the voltage reference signal generation module;

[0025] The inverter phase generation module calculates the phase information signal of the voltage reference signal according to the received voltage reference signal angular frequency information signal and sends it to the voltage reference signal generation module;

[0026] The voltage reference signal generating module calculates the voltage reference signal according to the received phase information signal and amplitude information signal and sends the voltage reference signal to the current loop reference signal generating module;

[0027] The current loop reference signal generation module calculates the current reference signal according to the received voltage reference signal and the voltage signal and sends the current reference signal to the current loop regulation module;

[0028] The current loop regulation module calculates the modulation signal and the carrier signal according to the received voltage signal, current reference signal and current signal, and sends them to the pulse width modulation module. The pulse width modulation module generates a duty cycle signal for controlling the inverter power switch according to the received signal, and sends it to the photoelectric conversion drive module;

[0029] The photoelectric conversion drive module outputs a power switch tube on or off signal according to the received duty cycle signal, and drives the power switch tube to be on or off.

[0030] Furthermore, the voltage rated amplitude correction value signal is calculated by formula (1):

[0031] Where ΔV n is the voltage rated amplitude correction value signal, is the voltage rated correction value reference, k q It is the voltage correction value minus the reactive power droop coefficient.

[0032] Furthermore, the reactive power droop set value signal is calculated by equation (2): d =(V n +ΔV n -V o )·k v (2);

[0033] In the formula, Q d is the reactive power droop given value signal, k v is the voltage-reactive power droop coefficient, V o is the voltage amplitude signal.

[0034] Furthermore, the active power droop set value signal is calculated by formula (3), the voltage reference signal angular frequency information signal is calculated by formula (4), and the phase information signal is calculated by formula (5):

[0035] P d =(ω n -ω o )·k f (3);

[0036]

[0037]

[0038] In the formula, θ o is the phase information signal, ω ois the voltage reference signal angular frequency information signal, P ref is the active power command value, P d is the active power droop given value signal, p o is the active power signal, J is the virtual moment of inertia, s is the Laplace transform integral operator, ω n is the voltage rated angular frequency, k f is the frequency-active power droop coefficient.

[0039] Furthermore, the amplitude information signal is calculated by formula (6):

[0040] Where V ref is the amplitude information signal, q o is the reactive power signal, Q ref is the reactive power command value, K is the integral coefficient, and s is the Laplace transform integral operator.

[0041] Furthermore, the voltage reference signal v is calculated by equation (9): refABC :

[0042]

[0043] Furthermore, the current reference signal i is calculated by equation (10): refABC :

[0044] Where L is the output virtual impedance, R is the output virtual resistance, s is the Laplace transform integral operator, and u is oABC is a voltage signal.

[0045] Furthermore, the modulation signal is calculated by formula (11):

[0046]

[0047] In the formula, v mABC is the modulation signal, k p is the proportional coefficient of the current loop regulation module, k i is the integral coefficient of the current loop regulation module, G Lead (s) is the voltage signal phase compensation link, i ABC is the current signal.

[0048] Furthermore, the voltage signal phase compensation link is calculated by equation (12):

[0049] Where: a is the phase compensation coefficient I, b is the phase compensation coefficient II, and c is the gain compensation coefficient.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The present invention collects current and voltage information in the inverter main circuit through a current collection module and a voltage, obtains active power and reactive power output by the inverter through a power calculation module, outputs a droop given value through a voltage-reactive power droop control and regulation module and an inverter output frequency-active power droop control and regulation module, and generates a control signal for driving a power switch to be turned on or off through a voltage reference signal generation module, a current loop reference signal generation module, a current loop regulation module, a pulse width modulation module and a photoelectric conversion drive module.

[0052] The invention can obtain the voltage signal and current signal of each inverter through the reactive power sharing control system based on the virtual synchronous machine parallel system, calculate the control signal for controlling the inverter power switch, and drive the power switch tube to open or close, thereby avoiding the reactive power unevenness and circulating current phenomenon of each inverter caused by inconsistent impedance parameters of the main circuit of each inverter in the virtual synchronous machine parallel system, realizing the average distribution of reactive power of multiple inverters and improving the safety of the virtual synchronous machine parallel system. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 Shown is a flow chart of the reactive power sharing control method based on the virtual synchronous machine parallel system of the present invention. DETAILED DESCRIPTION

[0054] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0055] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0056] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0057] Example 1

[0058] The present embodiment provides a reactive power sharing control system based on a virtual synchronous machine parallel system. The virtual synchronous machine parallel system includes a plurality of parallel three-phase inverter main circuits including input power and load. Each three-phase inverter main circuit is connected to a corresponding reactive power sharing control system. Each reactive power sharing control system includes a current acquisition module, a voltage acquisition module, a power calculation module, a voltage rated amplitude correction module, a frequency-active power droop control and adjustment module, a virtual moment of inertia module, an inverter phase generation module, a voltage reference signal generation module, an amplitude detection module, a voltage-reactive power droop control and adjustment module, an integral adjustment module, a voltage reference signal generation module, a current loop reference signal generation module, a current loop adjustment module, a pulse width modulation module and a photoelectric conversion drive module.

[0059] When this embodiment is applied, the current acquisition module obtains the current signal of the main circuit of the three-phase inverter, and the voltage acquisition module obtains the output voltage signal of the three-phase inverter; the output terminal I of the current acquisition module is connected to the power calculation module, and the output terminal II is connected to the current loop regulation module; the first output terminal of the voltage acquisition module is connected to the power calculation module; the two output terminals of the power calculation module are respectively connected to the input terminal of the voltage rated amplitude correction module and the first input terminal of the frequency-active power droop control regulation module, wherein the output terminal of the voltage rated amplitude correction module is connected to the second input terminal of the frequency-reactive power droop control regulation module; the output terminal of the frequency-active power droop control regulation module is connected to the virtual converter. The dynamic inertia module, the inverter phase generation module and the voltage reference signal generation module are connected in sequence, wherein the output end of the virtual rotation inertia module is connected to the third input end of the frequency-active power droop control and adjustment module; the second output end of the voltage acquisition module is connected to the amplitude detection module, the voltage-reactive power droop control and adjustment module, the integral adjustment module, the voltage reference signal generation module, the current loop reference signal generation module, the current loop adjustment module, the pulse width modulation module and the photoelectric conversion drive module in sequence, wherein the third output end of the voltage acquisition module is connected to the input end of the current loop reference signal generation module, and the fourth output end of the voltage acquisition module is connected to the input end of the current loop adjustment module;

[0060] In the application, the photoelectric conversion drive module communicates with the power switch tube of the three-phase inverter main circuit, and outputs a power switch tube on or off signal according to the duty cycle signal output by the pulse width modulation module, driving the power switch tube to turn on or off.

[0061] Example 2

[0062] This embodiment provides a reactive power sharing control method based on a virtual synchronous machine parallel system. The method is implemented based on the reactive power sharing control system based on a virtual synchronous machine parallel system provided in Example 1. Figure 1 , specifically including the following steps:

[0063] S1 current acquisition module obtains the current signal i ABC , and sent to the power calculation module and the current loop regulation module;

[0064] S2 voltage acquisition module obtains voltage signal u oABC , and sent to the power calculation module, the voltage amplitude detection module, the current loop reference signal generation module and the current loop adjustment module;

[0065] The S3 power calculation module receives the current signal i ABC And the voltage signal u oABC , calculate the active power signal p o and reactive power signal q o , and sent to the voltage rated amplitude correction module and the frequency-active power droop control and adjustment module respectively. The frequency-active power droop control and adjustment module receives the reactive power signal q o Send to the virtual moment of inertia module;

[0066] S4 voltage rated amplitude correction module receives the reactive power signal q o , calculate the voltage rated amplitude correction value signal ΔV n And sent to the voltage-reactive power droop control and regulation module;

[0067] S5 voltage amplitude detection module receives the voltage signal u oABC , calculate the output voltage amplitude signal V o And sent to the voltage-reactive power droop control and regulation module;

[0068] The S6 virtual moment of inertia module receives the active power signal p o , calculate the voltage reference signal angular frequency information signal ω o And sent to the voltage-reactive power droop control and regulation module and the inverter phase generation module;

[0069] S7 voltage-reactive power droop control and regulation module receives the voltage amplitude signal Vo And the voltage rated amplitude correction value signal ΔV n , calculate the reactive power droop given value signal Q d , according to the received voltage reference signal angular frequency information signal ω o , calculate the active power droop given value signal P d , and the reactive power droop set value signal Q d and active power droop set value signal P d Send to the integral adjustment module;

[0070] The S8 integral regulation module receives the reactive power droop set value signal Q d and active power droop set value signal P d , calculate the amplitude information signal V of the voltage reference signal ref and sent to the voltage reference signal generation module;

[0071] The S9 inverter phase generation module receives the voltage reference signal angular frequency information signal ω o , calculate the phase information signal θ of the voltage reference signal o and sent to the voltage reference signal generation module;

[0072] S10 voltage reference signal generation module receives the phase information signal θ o and amplitude information signal V ref , calculate the voltage reference signal v refABC And sent to the current loop reference signal generation module;

[0073] S11 current loop reference signal generation module receives the voltage reference signal v refABC And the voltage signal u oABC , calculate the current reference signal i refABC And sent to the current loop regulation module;

[0074] The S12 current loop regulation module receives the voltage signal u oABC , current reference signal i refABC and the current signal i ABC , calculate the modulation signal v mABC and the carrier signal v c And send it to the pulse width modulation module, the pulse width modulation module generates a duty cycle signal d for controlling the inverter power switch according to the received signal, and sends it to the photoelectric conversion drive module;

[0075] The S13 photoelectric conversion drive module outputs a power switch tube on or off signal according to the received duty cycle signal d, and drives the power switch tube to be on or off.

[0076] The present invention can obtain the voltage signal and current signal of each inverter through the reactive power sharing control system based on the virtual synchronous machine parallel system, thereby generating a control signal to control the inverter power switch, and driving the power switch tube to turn on or off. It can effectively improve the reactive power unevenness and circulating current problems of each inverter caused by inconsistent impedance parameters of the parallel connection lines of each inverter, realize the reactive power equalization function of the parallel system of multiple inverters, ensure the safe and reliable operation of the inverter parallel system, and provide an important technical foundation for the virtual synchronous machine parallel control scheme applied in the field of distributed power generation and microgrid.

[0077] Example 3

[0078] Based on Example 2, Figure 1 This embodiment also specifically introduces a voltage rated amplitude correction value signal, a reactive power droop given value signal, an active power droop given value signal, a voltage reference signal angular frequency information signal, a phase information signal, an amplitude information signal, a voltage reference signal v refABC , current reference signal i refABC , modulation signal and voltage signal phase compensation link calculation method.

[0079] (I) Calculation method of voltage rated amplitude correction value signal.

[0080] The voltage rated amplitude correction value signal is calculated by formula (1):

[0081]

[0082] Where ΔV n is the voltage rated amplitude correction value signal, is the voltage rated correction value reference, k q It is the voltage correction value minus the reactive power droop coefficient.

[0083] (ii) Calculation method of reactive power droop given value signal.

[0084] The reactive power droop set value signal is calculated by formula (2):

[0085] Q d =(V n +ΔV n -V o )·k v (2);

[0086] In the formula, Q d is the reactive power droop given value signal, k v is the voltage-reactive power droop coefficient, V o is the voltage amplitude signal.

[0087] (iii) Calculation method of active power droop set value signal, voltage reference signal angular frequency information signal and phase information signal.

[0088] The active power droop set value signal is calculated by formula (3):

[0089] P d =(ω n -ω o )·k f (3);

[0090] The voltage reference signal angular frequency information signal is calculated by formula (4):

[0091]

[0092] The phase information signal is calculated by formula (5):

[0093]

[0094] In the formula, θ o is the phase information signal, ω o is the voltage reference signal angular frequency information signal, P ref is the active power command value, P d is the active power droop given value signal, p o is the active power signal, J is the virtual moment of inertia, s is the Laplace transform integral operator, ω n is the voltage rated angular frequency, k f is the frequency-active power droop coefficient.

[0095] (iv) Calculation method of amplitude information signal.

[0096] The amplitude information signal is calculated by formula (6):

[0097]

[0098] Where V ref is the amplitude information signal, q o is the reactive power signal, Q ref is the reactive power command value, K is the integral coefficient, and s is the Laplace transform integral operator.

[0099] (V) Voltage reference signal v refABC The calculation method of .

[0100] The voltage reference signal v is calculated by formula (9): refABC :

[0101]

[0102] (VI) Current reference signal irefABC The calculation method of .

[0103]

[0104] Where L is the output virtual impedance, R is the output virtual resistance, s is the Laplace transform integral operator, and u is oABC is a voltage signal.

[0105] (VII) Calculation method of modulation signal.

[0106]

[0107] In the formula, v mABC is the modulation signal, k p is the proportional coefficient of the current loop regulation module, k i is the integral coefficient of the current loop regulation module, G Lead (s) is the voltage signal phase compensation link, i ABC is the current signal.

[0108] (VIII) Calculation method of voltage signal phase compensation link.

[0109]

[0110] Where: a is the phase compensation coefficient I, b is the phase compensation coefficient II, and c is the gain compensation coefficient.

[0111] Example 4

[0112] Based on the embodiment 2 or 3, the virtual synchronous machine parallel system of this embodiment includes two inverters to form an inverter, and the voltage U at both ends of each inverter is in For 800VDC, each inverter output filter inductor L f Both are 0.15mH, output filter capacitor C f Both are 200μF (delta connection). Output line parameter of one inverter is Z l 0.01+j3.14e -3 , the output line parameter of the other inverter is Z l 0.02+j6.28e -3 , the three-phase load is 0.2+j0.314.

[0113] When the impedance of the connection lines inside the virtual synchronous machine parallel system is inconsistent, the reactive power output by each inverter in the system will be different, resulting in serious reactive imbalance and reactive commutation. In this embodiment, when the virtual synchronous machine parallel system is not installed with the reactive power sharing control system based on the virtual synchronous machine parallel system of the present application, in the same time period, the waveforms of the active power current, reactive power current and output one-phase bridge arm current of the two inverters are very different.

[0114] When the reactive power sharing control system based on the virtual synchronous machine parallel system of the present application is installed on the virtual synchronous machine parallel system, and the system is executed using the reactive power sharing control method based on the virtual synchronous machine parallel system of the present application, there is almost no difference in the active power current, reactive power current and output single-phase bridge arm current waveforms of the two inverters in the same time period.

[0115] In summary, the present invention, on the basis of the reactive power sharing control system based on the virtual synchronous machine parallel system, executes the reactive power sharing control method based on the virtual synchronous machine parallel system, thereby realizing the load power sharing control of two inverters with different connection line parameters. It can be seen that the reactive power sharing control system based on the virtual synchronous machine parallel system and the reactive power sharing control method based on the virtual synchronous machine parallel system of the present application are both feasible.

[0116] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0117] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0118] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0119] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0120] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A reactive power sharing control system based on a virtual synchronous machine parallel system, the virtual synchronous machine parallel system comprising a plurality of parallel three-phase inverter main circuits including input power and load, characterized in that: Each three-phase inverter main circuit is connected to a corresponding reactive power sharing control system, and each reactive power sharing control system includes a current acquisition module, a voltage acquisition module, a power calculation module, a voltage rated amplitude correction module, a frequency-active power droop control and adjustment module, a virtual moment of inertia module, an inverter phase generation module, a voltage reference signal generation module, an amplitude detection module, a voltage-reactive power droop control and adjustment module, an integral adjustment module, a voltage reference signal generation module, a current loop reference signal generation module, a current loop adjustment module, a pulse width modulation module, and a photoelectric conversion drive module; The current acquisition module acquires the current signal of the main circuit of the three-phase inverter, and the voltage acquisition module acquires the output voltage signal of the three-phase inverter; The output terminal I of the current acquisition module is connected to the power calculation module, and the output terminal II is connected to the current loop regulation module; The first output end of the voltage acquisition module is connected to the power calculation module; The two output ends of the power calculation module are respectively connected to the input end of the voltage rated amplitude correction module and the first input end of the frequency-active power droop control adjustment module, wherein the output end of the voltage rated amplitude correction module is connected to the second input end of the frequency-reactive power droop control adjustment module; The output end of the frequency-active power droop control and adjustment module is connected to the virtual moment of inertia module, the inverter phase generation module and the voltage reference signal generation module in sequence, wherein the output end of the virtual moment of inertia module is connected to the third input end of the frequency-active power droop control and adjustment module; The second output end of the voltage acquisition module is connected to the amplitude detection module, the voltage-reactive power droop control and regulation module, the integral regulation module, the voltage reference signal generation module, the current loop reference signal generation module, the current loop regulation module, the pulse width modulation module and the photoelectric conversion drive module in sequence, wherein the third output end of the voltage acquisition module is connected to the input end of the current loop reference signal generation module, and the fourth output end of the voltage acquisition module is connected to the input end of the current loop regulation module; The photoelectric conversion drive module is communicatively connected to the power switch tube of the three-phase inverter main circuit, and outputs a power switch tube on or off signal according to the duty cycle signal output by the pulse width modulation module, so as to drive the power switch tube to be on or off; Wherein, the current loop reference signal generation module calculates the current reference signal according to the received voltage reference signal and voltage signal and sends it to the current loop adjustment module; The current loop regulation module calculates the modulation signal and the carrier signal according to the received voltage signal, current reference signal and current signal, and sends them to the pulse width modulation module; the pulse width modulation module generates a duty cycle signal for controlling the inverter power switch according to the received signal, and sends it to the photoelectric conversion drive module; The current reference signal The calculation formula is: In the formula, L is the output virtual impedance, R is the output virtual resistance, s is the Laplace transform integral operator, u oABC is the voltage signal; The calculation formula of the modulation signal is: In the formula, v mABC is the modulation signal, is the proportional coefficient of the current loop regulation module, is the integral coefficient of the current loop regulation module, G Lead ( s ) is the voltage signal phase compensation link, i ABC is the current signal; The calculation formula of the voltage signal phase compensation link is: In the formula, a is the phase compensation coefficient I, b is the phase compensation coefficient II, c is the gain compensation coefficient.

2. A reactive power sharing control method based on a virtual synchronous machine parallel system, characterized in that: The reactive power sharing control system based on the virtual synchronous machine parallel system according to claim 1 is implemented, comprising the following steps: The current acquisition module acquires the current signal and sends it to the power calculation module and the current loop regulation module; The voltage acquisition module acquires the voltage signal and sends it to the power calculation module, the voltage amplitude detection module, the current loop reference signal generation module and the current loop adjustment module; The power calculation module calculates the active power signal and the reactive power signal according to the received current signal and voltage signal, and sends them to the voltage rated amplitude correction module and the frequency-active power droop control and adjustment module respectively. The frequency-active power droop control and adjustment module sends the received reactive power signal to the virtual rotation inertia module; The voltage rated amplitude correction module calculates the voltage rated amplitude correction value signal according to the received reactive power signal and sends it to the voltage-reactive power droop control and adjustment module; The voltage amplitude detection module calculates the output voltage amplitude signal according to the received voltage signal and sends it to the voltage-reactive power droop control and regulation module; The virtual moment of inertia module calculates the voltage reference signal angular frequency information signal according to the received active power signal and sends it to the voltage-reactive power droop control and regulation module and the inverter phase generation module; The voltage-reactive power droop control and regulation module calculates the reactive power droop given value signal according to the received voltage amplitude signal and the voltage rated amplitude correction value signal, calculates the active power droop given value signal according to the received voltage reference signal angular frequency information signal, and sends the reactive power droop given value signal and the active power droop given value signal to the integral regulation module; The integral regulation module calculates the amplitude information signal of the voltage reference signal according to the received reactive power droop given value signal and the active power droop given value signal and sends the calculated amplitude information signal to the voltage reference signal generation module; The inverter phase generation module calculates the phase information signal of the voltage reference signal according to the received voltage reference signal angular frequency information signal and sends it to the voltage reference signal generation module; The voltage reference signal generating module calculates the voltage reference signal according to the received phase information signal and amplitude information signal and sends the voltage reference signal to the current loop reference signal generating module; The current loop reference signal generation module calculates the current reference signal according to the received voltage reference signal and the voltage signal and sends the current reference signal to the current loop regulation module; The current loop regulation module calculates the modulation signal and the carrier signal according to the received voltage signal, current reference signal and current signal, and sends them to the pulse width modulation module. The pulse width modulation module generates a duty cycle signal for controlling the inverter power switch according to the received signal, and sends it to the photoelectric conversion drive module; The photoelectric conversion drive module outputs a power switch tube on or off signal according to the received duty cycle signal, and drives the power switch tube to be on or off.

3. The reactive power sharing control method based on the virtual synchronous machine parallel system according to claim 2 is characterized in that: The voltage rated amplitude correction value signal is calculated by formula (4): In the formula, ∆ V n is the voltage rated amplitude correction value signal, For reference to the voltage rated correction value, is the voltage correction value minus the reactive power droop coefficient, is the reactive power signal.

4. The method for controlling reactive power sharing of a virtual synchronous machine parallel system according to claim 3, characterized in that: The reactive power droop set value signal is calculated by formula (5): In the formula, Q d is the reactive power droop given value signal, is the voltage-reactive power droop coefficient, V o is the voltage amplitude signal.

5. The method for controlling reactive power sharing of a virtual synchronous machine parallel system according to claim 4, characterized in that: The active power droop set value signal is calculated by equation (6), the voltage reference signal angular frequency information signal is calculated by equation (7), and the phase information signal is calculated by equation (8): In the formula, θ o is the phase information signal, ω o is the voltage reference signal angular frequency information signal, is the active power command value, P d It is the active power droop given value signal, p o is the active power signal, is the virtual moment of inertia, s is the Laplace transform integral operator, ω n is the voltage rated angular frequency, is the frequency-active power droop coefficient.

6. The method for controlling reactive power sharing of a virtual synchronous machine parallel system according to claim 5, characterized in that: The amplitude information signal is calculated by formula (9): In the formula, V ref is the amplitude information signal, q o is the reactive power signal, is the reactive power command value, is the integral coefficient, and s is the Laplace transform integral operator.

7. The method for controlling reactive power sharing of a virtual synchronous machine parallel system according to claim 6, characterized in that: The voltage reference signal is calculated by equation (10): v refABC :

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