Hybrid synchronous grid-connected converter control method and related device based on virtual admittance optimization design

Abstract

The embodiment of the present application discloses a hybrid synchronous grid-connected converter control method and related device based on virtual admittance optimization design, which calculates the instantaneous active power output by the system according to the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor; and inputs the instantaneous active power and the obtained active power instruction value into the power synchronization control loop and the phase-locked loop to obtain a hybrid synchronization control angle; inputs the two-phase voltage of the grid-side capacitor into the virtual admittance to obtain a two-phase reference current value; and inputs the two-phase current of the output filter inductor, the two-phase voltage of the grid-side capacitor and the two-phase reference current value into the AC current control loop to obtain a two-phase voltage control signal of the inverter; finally, transforms the two-phase voltage control signal according to the hybrid synchronization control angle to obtain a three-phase voltage control signal; and controls the opening and closing of the power device according to the three-phase voltage control signal. The use of this application is conducive to improving the steady-state stability of the grid-connected inverter under weak power grid.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic systems, and in particular to a hybrid synchronous grid-connected converter control method based on virtual admittance optimization design and related devices. Background Art

[0002] With the increasing proportion of renewable energy generators in power systems, power systems dominated by traditional synchronous generators are gradually evolving into new power systems dominated by power electronic converters. However, renewable energy generation systems are often located in the "Three Norths" (North China, North China, and North China) regions, far from load centers. Large-capacity, long-distance transmission, and transformer leakage inductance result in significant grid impedance. Furthermore, with the continuous integration of renewable energy stations, their grid-connected capacity is also increasing, resulting in a low short-circuit capacity ratio (SCR), or weak grid characteristics. In weak grids, the internal control loops of grid-connected inverters, such as the phase-locked loop (PLL) and alternating-current control (ACC), intensify the cross-coupling between them and the grid impedance, reducing system stability margins and seriously threatening the safe and stable operation of the power system. Summary of the Invention

[0003] The embodiments of the present application provide a hybrid synchronous grid-connected converter control method and related devices based on virtual admittance optimization design, which are beneficial to improving the steady-state stability of the grid-connected inverter under weak power grids.

[0004] A first aspect of an embodiment of the present application provides a hybrid synchronous grid-connected converter control method based on virtual admittance optimization design, the method comprising:

[0005] Calculating the instantaneous active power output by the system based on the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor; and inputting the instantaneous active power and the acquired active power command value into a power synchronization control loop and a phase-locked loop to obtain a hybrid synchronization control angle;

[0006] Inputting the two-phase voltage of the grid-side capacitor into a virtual admittance to obtain a two-phase reference current value; and inputting the two-phase current of the output filter inductor, the two-phase voltage of the grid-side capacitor and the two-phase reference current value into an AC current control loop to obtain a two-phase voltage control signal of the inverter;

[0007] transforming the two-phase voltage control signal according to the hybrid synchronous control angle to obtain a three-phase voltage control signal, where the two-phase refers to the d-axis and the q-axis in the synchronous rotating coordinate system, and the three-phase refers to the a-axis, the b-axis, and the c-axis in the stationary coordinate system;

[0008] The power device is controlled to be turned on and off according to the three-phase voltage control signal.

[0009] Optionally, before calculating the instantaneous active power output by the system based on the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor, the method further includes:

[0010] Collecting the three-phase current of the output filter inductor and the three-phase voltage of the grid-side capacitor;

[0011] The three-phase current of the output filter inductor and the three-phase voltage of the grid-side capacitor are respectively transformed to obtain the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor, and the transformation includes Park transformation and / or Clark transformation.

[0012] Optionally, controlling the turning on and off of a power device according to the three-phase voltage control signal includes:

[0013] Performing pulse width modulation on the three-phase voltage control signal to generate a pulse width modulated switching signal for a power device in the inverter;

[0014] The pulse width modulation switching signal is processed by a driving circuit to control the turning on and off of the power device.

[0015] Optionally, the calculating of the instantaneous active power output by the system based on the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor includes:

[0016] The instantaneous active power output by the system is calculated based on the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor and the first formula, where the first formula is:

[0017]

[0018] in, is the instantaneous active power output by the system, is the two-phase voltage of the grid-side capacitor, and are the two-phase currents of the output filter inductor.

[0019] Optionally, inputting the instantaneous active power and the acquired active power command value into a power synchronization control loop and a phase-locked loop to obtain a hybrid synchronization control angle includes:

[0020] Calculating the command angle according to the rated angular frequency of the grid voltage, the Laplace operator, and the second formula; calculating the phase-locked loop angle according to the q-axis voltage of the two-phase voltage of the grid-side capacitor, the proportional adjustment coefficient of the phase-locked loop, the Laplace operator, and the third formula; and calculating the synchronization loop angle according to the acquired active power command value, the instantaneous active power, the active power controller, the Laplace operator, and the fourth formula;

[0021] The hybrid synchronous control angle is calculated according to the command angle, the phase-locked loop angle, the synchronization loop angle, and the fifth formula; the second formula to the fifth formula are respectively:

[0022]

[0023]

[0024]

[0025]

[0026] in, 、 、 and are respectively the command angle, the phase-locked loop angle, the synchronization loop angle and the hybrid synchronization control angle, is the rated angular frequency of the grid voltage, s is the Laplace operator, is the q-axis voltage of the two-phase voltage of the grid-side capacitor, is the proportional adjustment coefficient of the phase-locked loop, is the active power instruction value, is the active power controller.

[0027] Optionally, inputting the two-phase voltages of the grid-side capacitor into a virtual admittance to obtain two-phase reference current values includes:

[0028] The two-phase reference current value is determined according to the two-phase voltage of the grid-side capacitor, the two-phase reference voltage value, the rated angular frequency of the grid voltage, the virtual inductance and virtual resistance of the virtual admittance, the Laplace operator, the proportional gain coefficient of the AC voltage control, the proportional gain coefficient of the active susceptance, and a sixth formula; the sixth formula is:

[0029]

[0030] in, and is the two-phase reference current value, and is the two-phase reference voltage value, and are the virtual inductance and virtual resistance of the virtual admittance, is the proportional gain coefficient of AC voltage control, is the proportional gain coefficient of the active susceptance.

[0031] Optionally, inputting the two-phase current of the output filter inductor, the two-phase voltage of the grid-side capacitor, and the two-phase reference current value into an AC current control loop to obtain a two-phase voltage control signal of the inverter includes:

[0032] The two-phase voltage control signal of the inverter is determined according to the two-phase current of the output filter inductor, the two-phase voltage of the grid-side capacitor, the two-phase reference current value, the output filter inductor, the transfer function of the AC current control loop, and a seventh formula. The seventh formula is:

[0033]

[0034] in, and is the two-phase voltage control signal, is the output filter inductor, is the transfer function of the AC current control loop.

[0035] A second aspect of the embodiments of the present application provides a hybrid synchronous grid-connected converter control device based on virtual admittance optimization design, the device comprising:

[0036] a control angle determination unit, configured to calculate the instantaneous active power output by the system based on the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor; and input the instantaneous active power and the acquired active power command value into a power synchronization control loop and a phase-locked loop to obtain a hybrid synchronization control angle;

[0037] a control signal determination unit, configured to input the two-phase voltages of the grid-side capacitor into a virtual admittance to obtain a two-phase reference current value; and input the two-phase current of the output filter inductor, the two-phase voltages of the grid-side capacitor, and the two-phase reference current value into an AC current control loop to obtain a two-phase voltage control signal of the inverter;

[0038] a control signal conversion unit, configured to convert the two-phase voltage control signal according to the hybrid synchronous control angle to obtain a three-phase voltage control signal, wherein the two-phase refers to the d-axis and the q-axis in the synchronous rotating coordinate system, and the three-phase refers to the a-axis, the b-axis, and the c-axis in the stationary coordinate system;

[0039] A switch control unit is used to control the switching on and off of the power device according to the three-phase voltage control signal.

[0040] A third aspect of the embodiments of the present application provides an electronic device, including: a processor and a memory;

[0041] The processor is connected to the memory, wherein the memory is used to store the computer program, and the processor is used to call the computer program to execute the method in the first aspect of the embodiment of the present application.

[0042] A fourth aspect of an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. The computer program includes program instructions. When the program instructions are executed by a processor, the method in the first aspect of the embodiment of the present application is executed.

[0043] It can be seen that in the embodiment of the present application, first, the instantaneous active power output by the system is calculated based on the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor; and the instantaneous active power and the obtained active power command value are input into the power synchronization control loop and the phase-locked loop to obtain a hybrid synchronization control angle. This power synchronization control method can improve the frequency support characteristics of the system; secondly, the two-phase voltage of the grid-side capacitor is input into the virtual admittance to obtain a two-phase reference current value. By adopting the virtual admittance control, the current during the fault period can be effectively suppressed and the stability during fault recovery can be improved; then, the two-phase current of the output filter inductor, the two-phase voltage of the grid-side capacitor and the two-phase reference current value are input into the AC current control loop to obtain a two-phase voltage control signal of the inverter, and a gain link of the AC voltage and active admittance is added to the virtual admittance link, thereby improving the voltage support characteristics of the grid-type inverter and significantly improving the steady-state stability of the converter; finally, the two-phase voltage control signal is transformed according to the hybrid synchronization control angle to obtain a three-phase voltage control signal, so that the power device can be turned on and off according to the three-phase voltage control signal. In summary, the embodiments of the present application are beneficial to improving the steady-state stability of the grid-connected inverter in a weak power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 A schematic structural diagram of a new energy grid-connected inverter system provided by an embodiment of the present application is shown.

[0046] Figure 2 A flow chart of a hybrid synchronous grid-connected converter control method based on virtual admittance optimization design provided by one embodiment of the present application is shown;

[0047] Figure 3 A schematic diagram of a hybrid synchronization control angle determination method provided by an embodiment of the present application is shown;

[0048] Figure 4 A schematic diagram illustrating a method for determining two-phase reference current values provided by an embodiment of the present application is shown;

[0049] Figure 5 The figure shows the output current waveform of the grid-connected inverter before and after the control strategy of the present application is adopted according to one embodiment of the present application;

[0050] Figure 6 A schematic structural diagram of a hybrid synchronous grid-connected converter control device based on virtual admittance optimization design provided by one embodiment of the present application is shown;

[0051] Figure 7 A schematic structural diagram of a computer device provided in one embodiment of the present application is shown. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0053] Please refer to Figure 1 , which shows a schematic diagram of the structure of a new energy grid-connected inverter system provided by an embodiment of the present application. Among them, the structure of the new energy grid-connected inverter system is divided into two parts: the main circuit and the controller. The topological structure diagram of the main circuit is as follows Figure 1 The main circuit includes an AC weak grid, a filter and a converter connected in sequence. The filter includes an output filter inductor. and the grid-side capacitor C, which is used to attenuate high-frequency switching harmonics, 、 Flowing through The three-phase current in the abc three-phase stationary coordinate system. The impedance of the AC weak grid is Ignore the voltage fluctuation on the DC side of the converter and use an ideal DC source Replaces the inverter power supply.

[0054] The topology of the controller is shown in the figure below: Figure 1The controller consists of a virtual admittance controller, a current loop (ACC), and a pulse width modulation (PWM) signal generator, all connected in sequence. Furthermore, the controller includes a hybrid synchronous control section, which includes a power synchronization control loop (PSC) and a phase-locked loop (PLL).

[0055] The point of common coupling (PCC) between the main circuit and the controller is located at , C and As shown by the dotted box in the figure.

[0056] The specific control process is as follows: The three-phase voltage of C 、 Convert to two-phase voltage via Clark and / or Park . Three-phase current 、 Can be converted to two-phase current by Clark and / or Park Among them, the three phases are the three axes abc of the stationary coordinate system, and the two phases are the two coordinate axes dq of the rotating coordinate system.

[0057] Then, on one side, through the two-phase voltage and two-phase current The instantaneous active power P output by the system can be calculated, and the instantaneous active power P and active power instruction value can be calculated. Input to the power synchronization control loop PSC and phase-locked loop PLL to obtain the hybrid synchronization control angle .

[0058] At the same time, on the other side, the two-phase voltage Input to the virtual admittance to obtain the two-phase reference current value and ; and the two-phase voltage and two-phase current And the two-phase reference current value and Input to the AC current control loop ACC to obtain the two-phase voltage control signal of the inverter and .

[0059] Finally, the hybrid synchronous control angle Two-phase voltage control signal for the inverter and Implement Clark and / or Park transformation to obtain three-phase voltage control signals . For three-phase voltage control signal Pulse width modulation (PWM) is performed to generate pulse width modulation (PWM) switching signals for the power devices in the inverter. The PWM switching signals are processed by the drive circuit to control the on and off of the power devices.

[0060] Please refer to Figure 2 , which shows a flow chart of a hybrid synchronous grid-connected converter control method based on virtual admittance optimization design provided by an embodiment of the present application. This method can be applied to Figure 1 The new energy grid-connected inverter system shown can include the following steps:

[0061] Step 201: Calculate the instantaneous active power output by the system according to the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor.

[0062] Furthermore, before executing step 201, the method further includes:

[0063] Collecting the three-phase current of the output filter inductor and the three-phase voltage of the grid-side capacitor;

[0064] The three-phase current of the output filter inductor and the three-phase voltage of the grid-side capacitor are respectively transformed to obtain the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor, and the transformation includes Park transformation and / or Clark transformation.

[0065] in, 、 is the three-phase current of the output filter inductor, 、 is the three-phase voltage of the grid side capacitor. is the two-phase voltage of the grid-side capacitor. Three-phase refers to the a, b, and c axes in a stationary coordinate system, while two-phase refers to the d and q axes in a synchronously rotating coordinate system. Three-phase systems are widely used in transmission lines due to their efficient transmission, balanced load, and high reliability. Two-phase systems provide sufficient accuracy and stability and are therefore used in control circuits.

[0066] Clark transform and Park transform are commonly used coordinate transformation techniques in the fields of power electronics and motor control. They are used to convert variables in a three-phase system into different coordinate systems for analysis and control. The transformation in this application can be a Clark transform, a Park transform, or both a Park transform and a Clark transform, without limitation.

[0067] Specifically, the instantaneous active power output by the system is calculated based on the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor, including:

[0068] The instantaneous active power output by the system is calculated based on the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor and the first formula, where the first formula is:

[0069]

[0070] in, is the instantaneous active power output by the system, is the two-phase voltage of the grid-side capacitor, and are the two-phase currents of the output filter inductor.

[0071] Instantaneous active power is the actual amount of electrical energy consumed in an AC circuit at a given moment. It represents the actual power loss in the circuit's resistive components, i.e., the portion that actually does work.

[0072] Step 202: Input the instantaneous active power and the acquired active power command value into a power synchronization control loop and a phase-locked loop to obtain a hybrid synchronization control angle.

[0073] Specifically, the step of inputting the instantaneous active power and the acquired active power command value into a power synchronization control loop and a phase-locked loop to obtain a hybrid synchronization control angle includes:

[0074] Calculating the command angle according to the rated angular frequency of the grid voltage, the Laplace operator, and the second formula; calculating the phase-locked loop angle according to the q-axis voltage of the two-phase voltage of the grid-side capacitor, the proportional adjustment coefficient of the phase-locked loop, the Laplace operator, and the third formula; and calculating the synchronization loop angle according to the acquired active power command value, the instantaneous active power, the active power controller, the Laplace operator, and the fourth formula;

[0075] The hybrid synchronous control angle is calculated according to the command angle, the phase-locked loop angle, the synchronization loop angle, and the fifth formula; the second formula to the fifth formula are respectively:

[0076]

[0077]

[0078]

[0079]

[0080] in, 、 、 and are respectively the command angle, the phase-locked loop angle, the synchronization loop angle and the hybrid synchronization control angle, is the rated angular frequency of the grid voltage, s is the Laplace operator, is the q-axis voltage of the two-phase voltage of the grid-side capacitor, is the proportional adjustment coefficient of the phase-locked loop, is the active power instruction value, is the active power controller.

[0081] in, , is the proportional adjustment coefficient of the active power controller, is the integral adjustment coefficient of the active power controller.

[0082] Among them, the active power controller (Power Synchronization Control, PSC) is a control device used in power systems or power electronic converters. Its main task is to adjust the active power output of the system so that it follows the predetermined active power command value. The active power command value is the target value of active power that a system or device should output or consume at a given moment. It is a reference value used to guide the controller to adjust the system's actual active power output to be close to or equal to the command value. Therefore, this value can be directly obtained.

[0083] Please refer to Figure 3 , which shows a schematic diagram of a hybrid synchronous control angle determination method provided by an embodiment of the present application.

[0084] Step 203: Input the two-phase voltages of the grid-side capacitor into the virtual admittance to obtain two-phase reference current values.

[0085] Virtual admittance (VA) is a technology used in power electronic converters and power system control. It improves the system's dynamic performance and stability by introducing virtual admittance characteristics into the control algorithm. VADA can simulate the admittance characteristics of actual physical components, thus optimizing system behavior without adding actual hardware.

[0086] Specifically, inputting the two-phase voltages of the grid-side capacitor into a virtual admittance to obtain two-phase reference current values includes:

[0087] The two-phase reference current value is determined according to the two-phase voltage of the grid-side capacitor, the two-phase reference voltage value, the rated angular frequency of the grid voltage, the virtual inductance and virtual resistance of the virtual admittance, the Laplace operator, the proportional gain coefficient of the AC voltage control, the proportional gain coefficient of the active susceptance, and a sixth formula; the sixth formula is:

[0088]

[0089] in, and is the two-phase reference current value, and is the two-phase reference voltage value, and are the virtual inductance and virtual resistance of the virtual admittance, is the proportional gain coefficient of AC voltage control, is the proportional gain coefficient of the active susceptance.

[0090] Please refer to Figure 4 , which shows a schematic diagram of a method for determining two-phase reference current values provided by an embodiment of the present application.

[0091] Step 204: Input the two-phase current of the output filter inductor, the two-phase voltage of the grid-side capacitor, and the two-phase reference current value into an AC current control loop to obtain a two-phase voltage control signal of the inverter.

[0092] Specifically, the two-phase current of the output filter inductor, the two-phase voltage of the grid-side capacitor, and the two-phase reference current value are input into the AC current control loop to obtain the two-phase voltage control signal of the inverter, including:

[0093] The two-phase voltage control signal of the inverter is determined according to the two-phase current of the output filter inductor, the two-phase voltage of the grid-side capacitor, the two-phase reference current value, the output filter inductor, the transfer function of the AC current control loop, and a seventh formula. The seventh formula is:

[0094]

[0095] in, and is the two-phase voltage control signal, is the output filter inductor, is the transfer function of the AC current control loop.

[0096] in, , is the current loop proportional adjustment coefficient, is the current loop integral adjustment coefficient.

[0097] It should be noted that the PI controller is currently the most common control method in industrial automation systems. In automated production processes, PI controllers are widely used to accurately control some fuzzy industrial processes. The PI controller has two adjustment parameters, namely proportional gain and integral time. For example, when applied to a current loop PI controller, the proportional gain is the current loop proportional adjustment coefficient mentioned above. , the integration time is the above current loop integration adjustment coefficient For example, when applied to a phase-locked loop PI controller, the proportional gain is the proportional adjustment coefficient of the phase-locked loop. , the integral time is the integral adjustment coefficient of the phase-locked loop .

[0098] Step 205: transform the two-phase voltage control signal according to the hybrid synchronous control angle to obtain a three-phase voltage control signal, where the two phases refer to the d-axis and q-axis in the synchronous rotating coordinate system, and the three phases refer to the a-axis, b-axis and c-axis in the stationary coordinate system.

[0099] Step 206: Control the on and off of the power device according to the three-phase voltage control signal.

[0100] Specifically, controlling the turning on and off of the power device according to the three-phase voltage control signal includes:

[0101] Performing pulse width modulation on the three-phase voltage control signal to generate a pulse width modulated switching signal for a power device in the inverter;

[0102] The pulse width modulation switching signal is processed by a driving circuit to control the turning on and off of the power device.

[0103] It should be noted that step 201 and step 202 and step 203 and step 204 can be executed simultaneously or sequentially, and there is no particular order in which they are executed.

[0104] It can be seen that in the embodiment of the present application, first, the instantaneous active power output by the system is calculated based on the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor; and the instantaneous active power and the obtained active power command value are input into the power synchronization control loop and the phase-locked loop to obtain a hybrid synchronization control angle. This power synchronization control method can improve the frequency support characteristics of the system; secondly, the two-phase voltage of the grid-side capacitor is input into the virtual admittance to obtain a two-phase reference current value. By adopting the virtual admittance control, the current during the fault period can be effectively suppressed and the stability during fault recovery can be improved; then, the two-phase current of the output filter inductor, the two-phase voltage of the grid-side capacitor and the two-phase reference current value are input into the AC current control loop to obtain a two-phase voltage control signal of the inverter, and a gain link of the AC voltage and active admittance is added to the virtual admittance link, thereby improving the voltage support characteristics of the grid-type inverter and significantly improving the steady-state stability of the converter; finally, the two-phase voltage control signal is transformed according to the hybrid synchronization control angle to obtain a three-phase voltage control signal, so that the power device can be turned on and off according to the three-phase voltage control signal. In summary, the embodiments of the present application are beneficial to improving the steady-state stability of the grid-connected inverter in a weak power grid.

[0105] In a specific embodiment of the present application, Figure 1 The parameters of the new energy grid-connected inverter system shown are: , , ;design , , , , , 285.6, 37.6, according to the above parameters Figure 2 The method in is used to draw the grid-connected point current output waveform.

[0106] Figure 5 The following is a graph showing the output current waveform of the grid-connected inverter before and after the control strategy of the present application is adopted according to the above parameters when the grid short-circuit ratio is 1.2 (SCR = 1.2, extremely weak grid). Figure 5 It can be clearly found that after adopting the embodiments of the present application, the grid-connected inverter under the extremely weak power grid can operate stably and the output current is not distorted; if the embodiments of the present application are not adopted, the output current of the grid-connected inverter is greatly distorted, the harmonic content is significantly increased, and the low-frequency oscillation problem of the grid-connected inverter is aggravated.

[0107] Figure 6 The following is a schematic diagram of a hybrid synchronous grid-connected converter control device based on virtual admittance optimization design according to an embodiment of the present application, which is applied to a new energy grid-connected AC system. The device includes:

[0108] A control angle determination unit 601 is configured to calculate the instantaneous active power output by the system based on the two-phase currents of the output filter inductor and the two-phase voltages of the grid-side capacitor; and input the instantaneous active power and the acquired active power command value into a power synchronization control loop and a phase-locked loop to obtain a hybrid synchronization control angle;

[0109] a control signal determining unit 602 configured to input the two-phase voltages of the grid-side capacitor into a virtual admittance to obtain two-phase reference current values; and input the two-phase currents of the output filter inductor, the two-phase voltages of the grid-side capacitor, and the two-phase reference current values into an AC current control loop to obtain two-phase voltage control signals for the inverter;

[0110] a control signal conversion unit 603 for converting the two-phase voltage control signal according to the hybrid synchronous control angle to obtain a three-phase voltage control signal, where the two-phase refers to the d-axis and the q-axis in the synchronous rotating coordinate system, and the three-phase refers to the a-axis, the b-axis, and the c-axis in the stationary coordinate system;

[0111] The switch control unit 604 is configured to control the switching on and off of the power device according to the three-phase voltage control signal.

[0112] Figure 7 A structural schematic diagram of a computer device provided in one embodiment of the present application is shown, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the functions of a computer system of a hybrid synchronous grid-connected converter control method based on virtual admittance optimization design in any of the above-mentioned embodiments are implemented.

[0113] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a computer, the computer performs the functions of a computer system of a hybrid synchronous grid-connected converter control method based on virtual admittance optimization design in any of the above-mentioned embodiments.

[0114] An embodiment of the present application also provides a computer program product comprising instructions, which, when executed by a computer, enables the computer to perform the functions of a computer system of a hybrid synchronous grid-connected converter control method based on virtual admittance optimization design in any of the above embodiments.

[0115] It should be understood that the specific examples in this application are only intended to help those skilled in the art better understand the embodiments of this application, rather than to limit the scope of the present invention.

[0116] It can be understood that in the various implementation methods of this application, the size of the serial number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation method of this application.

[0117] It can be understood that the various embodiments described in this application can be implemented individually or in combination, and the embodiments of this application are not limited to this.

[0118] Unless otherwise indicated, all technical and scientific terms used in the embodiments of the present application have the same meaning as those commonly understood by those skilled in the art in the technical field of the present application. The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit the scope of this application. The term "and / or" used in this application includes any and all combinations of one or more related listed items. The singular forms "a", "above", and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates otherwise.

[0119] It is understood that the processor in the embodiments of the present application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above-mentioned method embodiment can be completed by hardware integrated logic circuits in the processor or software instructions. The above-mentioned processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The various methods, steps, and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of the present application can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above-mentioned method.

[0120] It will be understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (programmable ROM, PROM), an erasable programmable read-only memory (erasable PROM, EPROM), an electrically erasable programmable read-only memory (EEPROM) or flash memory. The volatile memory may be a random access memory (RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0121] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0122] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems, devices and units can refer to the corresponding processes in the aforementioned method implementation methods and will not be repeated here.

[0123] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0124] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0125] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0126] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various implementation methods of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0127] The above are only specific embodiments of the present application, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A hybrid synchronous grid-connected converter control method based on virtual admittance optimization design, characterized in that: The method comprises: The instantaneous active power output by the system is calculated based on the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor and the first formula, where the first formula is: in, is the instantaneous active power output by the system, is the two-phase voltage of the grid-side capacitor, and is the two-phase current of the output filter inductor; Calculating the command angle according to the rated angular frequency of the grid voltage, the Laplace operator, and the second formula; calculating the phase-locked loop angle according to the q-axis voltage of the two-phase voltage of the grid-side capacitor, the proportional adjustment coefficient of the phase-locked loop, the Laplace operator, and the third formula; and calculating the synchronization loop angle according to the acquired active power command value, the instantaneous active power, the active power controller, the Laplace operator, and the fourth formula; The hybrid synchronous control angle is calculated according to the command angle, the phase-locked loop angle, the synchronization loop angle, and the fifth formula; the second formula to the fifth formula are respectively: in, 、 、 and are respectively the command angle, the phase-locked loop angle, the synchronization loop angle and the hybrid synchronization control angle, is the rated angular frequency of the grid voltage, s is the Laplace operator, is the q-axis voltage of the two-phase voltage of the grid-side capacitor, is the proportional adjustment coefficient of the phase-locked loop, is the active power instruction value, is the active power controller; Inputting the two-phase voltage of the grid-side capacitor into a virtual admittance to obtain a two-phase reference current value; and inputting the two-phase current of the output filter inductor, the two-phase voltage of the grid-side capacitor and the two-phase reference current value into an AC current control loop to obtain a two-phase voltage control signal of the inverter; transforming the two-phase voltage control signal according to the hybrid synchronous control angle to obtain a three-phase voltage control signal, where the two-phase refers to the d-axis and the q-axis in the synchronous rotating coordinate system, and the three-phase refers to the a-axis, the b-axis, and the c-axis in the stationary coordinate system; The power device is controlled to be turned on and off according to the three-phase voltage control signal.

2. The method according to claim 1, characterized in that Before calculating the instantaneous active power output by the system based on the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor, the method further includes: Collecting the three-phase current of the output filter inductor and the three-phase voltage of the grid-side capacitor; The three-phase current of the output filter inductor and the three-phase voltage of the grid-side capacitor are respectively transformed to obtain the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor, and the transformation includes Park transformation and / or Clark transformation.

3. The method according to claim 1, characterized in that The controlling the turning on and off of the power device according to the three-phase voltage control signal includes: Performing pulse width modulation on the three-phase voltage control signal to generate a pulse width modulated switching signal for a power device in the inverter; The pulse width modulation switching signal is processed by a driving circuit to control the turning on and off of the power device.

4. The method according to claim 1, wherein The step of inputting the two-phase voltages of the grid-side capacitor into a virtual admittance to obtain two-phase reference current values includes: The two-phase reference current value is determined according to the two-phase voltage of the grid-side capacitor, the two-phase reference voltage value, the rated angular frequency of the grid voltage, the virtual inductance and virtual resistance of the virtual admittance, the Laplace operator, the proportional gain coefficient of the AC voltage control, the proportional gain coefficient of the active susceptance, and a sixth formula; the sixth formula is: in, and is the two-phase reference current value, and is the two-phase reference voltage value, and are the virtual inductance and virtual resistance of the virtual admittance, is the proportional gain coefficient of AC voltage control, is the proportional gain coefficient of the active susceptance.

5. The method according to claim 4, characterized in that The step of inputting the two-phase current of the output filter inductor, the two-phase voltage of the grid-side capacitor, and the two-phase reference current value into an AC current control loop to obtain a two-phase voltage control signal of the inverter includes: The two-phase voltage control signal of the inverter is determined according to the two-phase current of the output filter inductor, the two-phase voltage of the grid-side capacitor, the two-phase reference current value, the output filter inductor, the transfer function of the AC current control loop, and a seventh formula. The seventh formula is: in, and is the two-phase voltage control signal, is the output filter inductor, is the transfer function of the AC current control loop.

6. A hybrid synchronous grid-connected converter control device based on virtual admittance optimization design, characterized in that: The device comprises: The control angle determination unit is configured to calculate the instantaneous active power output by the system based on the two-phase current of the output filter inductor and the two-phase voltage of the grid-side capacitor and a first formula, wherein the first formula is: in, is the instantaneous active power output by the system, is the two-phase voltage of the grid-side capacitor, and is the two-phase current of the output filter inductor; The control angle determination unit is further configured to calculate a command angle based on the rated angular frequency of the grid voltage, a Laplace operator, and a second formula; calculate a phase-locked loop angle based on the q-axis voltage of the two-phase voltage of the grid-side capacitor, a proportional adjustment coefficient of the phase-locked loop, a Laplace operator, and a third formula; and calculate a synchronization loop angle based on the acquired active power command value, the instantaneous active power, the active power controller, the Laplace operator, and a fourth formula; The control angle determination unit is further configured to calculate a hybrid synchronous control angle based on the command angle, the phase-locked loop angle, the synchronization loop angle, and a fifth formula; the second formula to the fifth formula are respectively: in, 、 、 and are respectively the command angle, the phase-locked loop angle, the synchronization loop angle and the hybrid synchronization control angle, is the rated angular frequency of the grid voltage, s is the Laplace operator, is the q-axis voltage of the two-phase voltage of the grid-side capacitor, is the proportional adjustment coefficient of the phase-locked loop, is the active power instruction value, is the active power controller; a control signal determination unit, configured to input the two-phase voltages of the grid-side capacitor into a virtual admittance to obtain a two-phase reference current value; and input the two-phase current of the output filter inductor, the two-phase voltages of the grid-side capacitor, and the two-phase reference current value into an AC current control loop to obtain a two-phase voltage control signal of the inverter; a control signal conversion unit, configured to convert the two-phase voltage control signal according to the hybrid synchronous control angle to obtain a three-phase voltage control signal, wherein the two-phase refers to the d-axis and the q-axis in the synchronous rotating coordinate system, and the three-phase refers to the a-axis, the b-axis, and the c-axis in the stationary coordinate system; A switch control unit is used to control the switching on and off of the power device according to the three-phase voltage control signal.

7. An electronic device, characterized in that: include: processor and memory; The processor is connected to a memory, wherein the memory is used to store a computer program, and the processor is used to call the computer program to execute the method according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, wherein the computer program includes program instructions. When the program instructions are executed by a processor, the method according to any one of claims 1 to 5 is executed.

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