Power quality control function multiplexing control method and device of network-forming inverter

Abstract

The invention discloses an electric energy quality control function multiplexing control method and device of a network-forming inverter. The method comprises the following steps: acquiring real-time operation parameters of an inverter; wherein the real-time operation parameters at least comprise inverter side current, network side current and capacitor voltage of a filter capacitor; determining a reference voltage corresponding to the inverter according to the grid-side current, the capacitor voltage and a preset working parameter; generating a harmonic part instruction of the inverter inductive current based on a preset power grid harmonic compensation current instruction, the inverter side current and the grid side current; determining a target control parameter according to the inverter side current, the capacitor voltage, the reference voltage and the harmonic part instruction; and controlling a switching tube of the inverter according to the target control parameter. By seamlessly integrating the electric energy quality treatment function in the existing network construction type inverter topological structure, the inverter can be controlled to realize network construction type control and reuse of the electric energy quality treatment function at the same time, the electric energy quality of the power grid can be improved, and meanwhile, the application scene is wide.

Description

Technical Field

[0001] The present invention relates to the technical field of grid-connected power generation, and in particular to a method and device for multiplexing and controlling power quality management functions of a grid-connected inverter. Background Art

[0002] As distributed energy sources such as photovoltaics, wind power and energy storage account for an increasing proportion of new power systems, their grid-side inverters have gradually begun to transition from the original grid-following control mode to grid-building control to maintain grid frequency stability.

[0003] In the prior art, the hardware topology of the grid-connected inverter and the power quality management device have commonalities. Both are based on the topology of the three-phase full-bridge inverter. At the same time, under most operating conditions, the active power output of the inverter does not reach its rated value, and there is a waste of inverter capacity. Therefore, reusing inverters for power quality management has high research value and practical value.

[0004] Although there were some sporadic ideas about reusing inverters for power quality management in the early days, they were all only in the inverter's grid-following mode. However, for grid-building control, the essence is to perform closed-loop control on the baseband voltage vector, and its control architecture is completely different from that of grid-following control. Therefore, how to reuse the power quality management function on the grid-building control architecture is a problem that needs to be solved. Summary of the invention

[0005] The present invention provides a method and device for multiplexing and controlling the power quality management function of a grid-type inverter, so as to solve the problem of multiplexing and realizing the power quality management function on a grid-type control architecture.

[0006] According to one aspect of the present invention, a method for controlling power quality management functions of a grid-connected inverter is provided, the method comprising:

[0007] Acquire real-time operating parameters of the inverter; wherein the real-time operating parameters include at least: inverter-side current, grid-side current and capacitor voltage of the filter capacitor;

[0008] Determine the reference voltage corresponding to the inverter according to the grid-side current, capacitor voltage and preset working parameters;

[0009] Generate a harmonic part instruction of the inverter inductor current based on a preset grid harmonic compensation current instruction, the inverter side current and the grid side current;

[0010] Determine the target control parameters according to the inverter side current, capacitor voltage, reference voltage and harmonic part instructions;

[0011] The switch tube of the inverter is controlled according to the target control parameters.

[0012] According to another aspect of the present invention, a power quality management function multiplexing control device for a grid-connected inverter is provided, the device comprising:

[0013] A parameter acquisition module, used to acquire real-time operating parameters of the inverter; wherein the real-time operating parameters at least include: inverter side current, grid side current and capacitor voltage of the filter capacitor;

[0014] A reference voltage determination module is used to determine a reference voltage corresponding to the inverter according to the grid-side current, capacitor voltage and preset working parameters;

[0015] A harmonic part instruction generation module, used for generating a harmonic part instruction of the inverter inductor current based on a preset power grid harmonic compensation current instruction, an inverter side current and a grid side current;

[0016] A target control parameter determination module is used to determine the target control parameter according to the inverter side current, capacitor voltage, reference voltage and harmonic part instructions;

[0017] The inverter control module is used to control the switch tube of the inverter according to the target control parameters.

[0018] According to another aspect of the present invention, there is provided an electronic device, the electronic device comprising:

[0019] at least one processor; and

[0020] a memory communicatively connected to the at least one processor; wherein,

[0021] The memory stores a computer program that can be executed by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the power quality management function multiplexing control method of the grid-connected inverter described in any embodiment of the present invention.

[0022] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the power quality management function multiplexing control method of a grid-connected inverter as described in any embodiment of the present invention when executed.

[0023] The technical solution of the embodiment of the present invention, on the basis of the basic meshing control based on a determined reference voltage, adds an additional input of a preset grid harmonic compensation current instruction required for power quality management to generate a corresponding target control parameter, and then controls the switch tube of the inverter according to the target control parameter, thereby solving the problem of multiplexing the power quality management function on the meshing control architecture, and realizing the seamless integration of the power quality management function in the existing meshing inverter topology structure, which can control the inverter to realize meshing control while realizing the multiplexing of the power quality management function; by injecting suitable harmonics into the power grid to compensate for the harmonics in the existing power grid and thus improve the power quality of the power grid, the utilization rate of the inverter resources is improved at the same time, and the application scenarios are wide.

[0024] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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 creative work.

[0026] Figure 1 This is a schematic diagram of the topological structure of a power quality management function multiplexing control system of a grid-type inverter provided according to the first embodiment of the present invention;

[0027] Figure 2 This is a flow chart of a power quality management function multiplexing control method of a grid-type inverter provided in accordance with the first embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the topological structure of a power quality management function multiplexing control system of a grid-type inverter provided according to the second embodiment of the present invention;

[0029] Figure 4 This is a flow chart of a power quality management function multiplexing control method of a grid-connected inverter provided in accordance with the second embodiment of the present invention;

[0030] Figure 5 is a control block diagram of a power quality management module provided according to Embodiment 2 of the present invention;

[0031] Figure 6 2 is a schematic diagram of a structure of a power quality management function multiplexing control device for a grid-connected inverter provided in accordance with a third embodiment of the present invention;

[0032] Figure 7 It is a structural schematic diagram of an electronic device for implementing the power quality management function multiplexing control method of a grid-connected inverter according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0035] Embodiment 1

[0036] Figure 1 A schematic diagram of the topological structure of a power quality management function multiplexing control system of a grid-type inverter provided in the first embodiment of the present invention. Figure 1 As shown, the power quality management function multiplexing control system includes: an inverter, a reference voltage calculation module, a power quality management module and a PWM modulation module. The structure of the power quality management function multiplexing control system of this embodiment is specifically described below.

[0037] Reference voltage calculation module, used to calculate the voltage based on preset working parameters and the collected grid-side current i2 and capacitor voltage u c And determine the reference voltage u corresponding to the inverter through any kind of network algorithm ref .

[0038] The power quality management module specifically includes: a harmonic part instruction generation module and a target control parameter determination module, wherein the harmonic part instruction generation module is used to generate a preset grid harmonic compensation current instruction i1 according to the collected inverter side current i1 and grid side current i2 and the preset grid harmonic compensation current instruction i2 required for grid power quality management.inject.h , generating the harmonic part command i of the inverter inductor current ref.h ; Target control parameter determination module, used to determine the inverter side current i1, capacitor voltage u c , reference voltage u ref and harmonic part instructions i ref.h Perform voltage and current dual closed-loop control to determine the corresponding target control parameters.

[0039] The PWM modulation module is used to output the corresponding PWM modulation signal according to the target control parameter to control the switch tube of the inverter.

[0040] like Figure 1 As shown in Figure 1, the grid-connected inverter and the AC grid intersect at the common grid connection point (Point of Common Coupling, PCC). dc is the DC side voltage of the inverter; L1 is the inductance of the inverter output filter; i1 is the inverter side current; C is the capacitance of the inverter output filter; i2 is the grid side current; u c is the capacitor voltage of the inverter filter capacitor, that is, the voltage output by the inverter; Z line is the equivalent impedance of the inverter connected to the grid; u pcc is the voltage at PCC; i g is the grid-side current of the inverter; L g The equivalent inductance of the grid to which the inverter is connected; u g is the grid voltage.

[0041] Based on the above power quality management function multiplexing control system, Figure 2 A flow chart of a method for multiplexing and controlling the power quality management functions of a grid-type inverter is provided for the first embodiment of the present invention. This embodiment can be applied to seamlessly integrate the power quality management functions into the grid-type inverter to realize grid harmonic compensation by multiplexing the inverter to improve the power quality of the grid. The method can be executed by a multiplexing and controlling device for the power quality management functions of the grid-type inverter. The multiplexing and controlling device for the power quality management functions of the grid-type inverter can be implemented in the form of hardware and / or software. The multiplexing and controlling device for the power quality management functions of the grid-type inverter can be configured in an electronic device. Figure 2 As shown, the first embodiment provides a method for controlling the power quality management function reuse of a grid-connected inverter, which specifically includes the following steps:

[0042] S110, obtaining real-time operating parameters of the inverter; wherein the real-time operating parameters at least include: inverter-side current, grid-side current, and capacitor voltage of the filter capacitor.

[0043] In the embodiment of the present invention, the real-time operating parameters of the inverter can be obtained through some pre-configured power grid data acquisition devices, wherein the real-time operating parameters can at least include: the inverter side current i1, the grid side current i2 and the capacitor voltage u of the filter capacitor c Specifically, the inverter side current i1 and the grid side current i2 can be collected by a current collection device such as a current transformer, and the capacitor voltage u of the filter capacitor can be collected by a voltage collection device such as a voltage transformer. c It is understandable that, in addition to using the above-mentioned current transformer and voltage transformer, this embodiment can also collect the current and voltage at each point on the grid-connected line through other automatic collection terminals, that is, this embodiment does not specifically limit the way of collecting current and voltage.

[0044] S120: Determine a reference voltage corresponding to the inverter according to the grid-side current, capacitor voltage and preset operating parameters.

[0045] The preset working parameters may include at least: preset active power P set and preset reactive power Q set , preset active power P set Indicates the given value of the inverter output active power, that is, the active power rating; preset reactive power Q set Indicates the given value of the inverter output reactive power, that is, the reactive power rating. The reference voltage can refer to a voltage command generated by any grid-forming algorithm based on the grid-side current, capacitor voltage and preset operating parameters.

[0046] like Figure 1 As shown, in the embodiment of the present invention, the preset working parameters and the collected grid-side current i2 and capacitor voltage u c Input to the reference voltage calculation module to determine the reference voltage u corresponding to the inverter ref ; Wherein, the preset working parameters may at least include: preset active power P set and preset reactive power Q set Specifically, the collected grid-side current i2 and capacitor voltage u c Determine the instantaneous active power P output by the inverter out and instantaneous reactive power Q out , and then the instantaneous active power P is calculated through the power loop out and instantaneous reactive power Q out , preset active power P set and preset reactive power Q set Calculate and get the reference voltage u ref Among them, the specific algorithms of instantaneous active power, instantaneous reactive power and power loop can refer to the existing technology, and this embodiment will not be repeated here.

[0047] S130. Generate a harmonic part instruction of the inverter inductor current based on a preset grid harmonic compensation current instruction, the inverter side current and the grid side current.

[0048] Among them, the preset grid harmonic compensation current instruction can be understood as a pre-configured instruction for compensating for grid harmonics required for grid power quality management. It can be manually set according to historical harmonic compensation conditions, expert experience, etc., or it can be based on the real-time operation of the current power grid and inverter, and adaptively determined by deep learning, heuristic algorithms, etc. This embodiment does not impose specific restrictions on this.

[0049] like Figure 1 As shown, in the embodiment of the present invention, the collected inverter side current i1 and grid side current i2, as well as the preset grid harmonic compensation current instruction i required for grid power quality management, can be used to generate a grid current i1. inject.h , are input to the harmonic part instruction generation module in the power quality management module, thereby generating the harmonic part instruction i of the inverter inductor current ref.h Specifically, the inverter side current i1 and the grid side current i2 can be subtracted and then compared with the preset grid harmonic compensation current instruction i inject.h The summed result is used as the input of the pre-configured proportional resonant controller to generate the harmonic part command i of the inverter inductor current. ref.h .

[0050] S140, determining target control parameters according to the inverter side current, capacitor voltage, reference voltage and harmonic part instructions.

[0051] like Figure 1 As shown, in the embodiment of the present invention, the inverter side current i1 and the capacitor voltage u c , reference voltage u ref and harmonic part instructions i ref.h The target control parameter determination module in the power quality management module is inputted, and the corresponding target control parameter is outputted through the dual control algorithm of the voltage outer loop and the current inner loop; wherein, the target control parameter can be understood as a parameter for controlling the duty cycle of the inverter. Specifically, it can be based on the capacitor voltage u c and reference voltage u ref Perform voltage outer loop control to obtain reference current i ref ; Based on the reference current i ref , the inverter side current i1 and the harmonic part command i generated above ref.h Perform current inner loop control to obtain target control parameters.

[0052] S150: Control the switch tube of the inverter according to the target control parameter.

[0053] Among them, the switching tube may refer to an electric power control switching device used to convert direct current into alternating current. Its function is to control the flow direction and size of electric energy in the inverter output circuit. The switching tube may include but is not limited to: Insulated Gate Bipolar Transistor (IGBT), Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), etc.

[0054] In the embodiment of the present invention, Figure 1 As shown, in the embodiment of the present invention, the above-determined target control parameters can be input into the PWM modulation module, so that the PWM modulation module outputs a PWM modulation signal corresponding to the duty cycle, and then the PWM modulation signal is used to control the working state of the switch tube of the inverter, that is, cut off or on, to achieve the capacitor voltage u output by the inverter c The amplitude and phase are the same as the given reference voltage u ref Maintain consistency, thereby achieving the reuse of inverters for grid power quality management under variable distributed energy conditions, that is, using the surplus capacity of the inverter under most conditions to compensate for harmonics in the grid to improve the grid power quality, while improving the utilization rate of the inverter capacity and reducing the waste of inverter resources.

[0055] The technical solution of the embodiment of the present invention, on the basis of the basic meshing control based on a determined reference voltage, adds an additional input of a preset grid harmonic compensation current instruction required for power quality management to generate a corresponding target control parameter, and then controls the switch tube of the inverter according to the target control parameter, thereby solving the problem of multiplexing the power quality management function on the meshing control architecture, and realizing the seamless integration of the power quality management function in the existing meshing inverter topology structure, which can control the inverter to realize meshing control while realizing the multiplexing of the power quality management function; by injecting suitable harmonics into the power grid to compensate for the harmonics in the existing power grid and thus improve the power quality of the power grid, the utilization rate of the inverter resources is improved at the same time, and the application scenarios are wide.

[0056] Embodiment 2

[0057] Figure 3 A schematic diagram of the topological structure of a power quality management function multiplexing control system of a grid-type inverter provided in the second embodiment of the present invention. Figure 3 As shown, the power quality management function multiplexing control system of this embodiment is a further optimization of the power quality management function multiplexing control system based on the above embodiment. Specifically, the reference voltage calculation module includes:

[0058] The instantaneous power calculation unit is used to calculate the instantaneous power according to the collected grid-side current i2 and capacitor voltage u c Determine the instantaneous active power P output by the inverter out and instantaneous reactive power Q out ;

[0059] Power loop, used to calculate the instantaneous active power P according to any network configuration algorithm out and instantaneous reactive power Q out , preset active power P set and preset reactive power Q set Calculate and get the reference voltage u ref The corresponding reference voltage amplitude V ref and the reference voltage phase θ ref ;

[0060] The voltage command calculation unit is used to calculate the voltage according to the reference voltage amplitude V ref and the reference voltage phase θ ref Perform voltage synthesis to obtain the reference voltage u in the three-phase coordinate system ref .

[0061] Based on the above power quality management function multiplexing control system, Figure 4 The flowchart of a power quality management function multiplexing control method of a grid-type inverter provided in the second embodiment of the present invention is further optimized and expanded based on the above implementation mode, and can be combined with various optional technical solutions in the above implementation mode. Figure 4 As shown, the second embodiment provides a method for controlling the power quality management function reuse of a grid-connected inverter, which specifically includes the following steps:

[0062] S210. Acquire real-time operating parameters of the inverter; wherein the real-time operating parameters include at least: inverter-side current, grid-side current, and capacitor voltage of the filter capacitor.

[0063] S220 , performing Clarke transformation on the grid-side current and capacitor voltage in the three-phase coordinate system to obtain a target grid-side current and a target capacitor voltage in the two-phase coordinate system.

[0064] Among them, Clark transformation is a commonly used coordinate transformation method in three-phase power systems, which can convert electrical quantities in a three-phase stationary coordinate system (abc coordinate system) into a two-phase stationary coordinate system (αβ coordinate system). The target grid-side current and target capacitor voltage can be understood as the grid-side current and capacitor voltage converted from the three-phase coordinate system to the two-phase coordinate system, respectively.

[0065] In the embodiment of the present invention, Figure 3 As shown, in the embodiment of the present invention, the collected grid-side current i2 and capacitor voltage u cInput to the instantaneous power calculation unit, and use Clark transformation to convert the grid-side current i2 and capacitor voltage u in the three-phase coordinate system c , converted into the target grid-side current and target capacitor voltage in the two-phase coordinate system.

[0066] S230 . Perform power calculation based on the target grid-side current and the target capacitor voltage to obtain instantaneous active power and instantaneous reactive power output by the inverter.

[0067] In the embodiment of the present invention, the instantaneous active power P output by the inverter can be determined using the following formula: out and instantaneous reactive power Q out :

[0068] P out =u cα i 2α +u cβ i 2β

[0069] Q out =u cβ i 2α -u cα i 2β

[0070] Among them, i 2α and i 2β They represent the α and β components of the target grid-side current respectively; u cα and u cβ They represent the α and β components of the target capacitor voltage respectively.

[0071] S240, based on the preset active power and the preset reactive power and through any kind of meshing algorithm, determine the reference voltage phase and the reference voltage amplitude corresponding to the instantaneous active power and the instantaneous reactive power, and synthesize the reference voltage phase and the reference voltage amplitude into a reference voltage.

[0072] The meshing algorithm in this embodiment includes at least one of the following: a droop control algorithm, a matching control algorithm, a virtual synchronous generator simulation algorithm, etc. Exemplarily, the corresponding reference voltage can be determined by simulating the rotor motion and excitation characteristics of the synchronous generator.

[0073] like Figure 3 As shown, in the embodiment of the present invention, the preset active power P set and preset reactive power Q set , and the instantaneous active power P determined above out and instantaneous reactive power Q out The two are input to the power loop to generate the corresponding reference voltage amplitude V ref and virtual angular frequency ω m, and then by the virtual angular frequency ω m The reference voltage phase θ is obtained by integration ref , thereby realizing power regulation, the core control equation is expressed as follows:

[0074] P set -P out -D p (ω m -ω0)=Jω0s

[0075]

[0076] Where ω0 is the rated angular frequency; J is the virtual moment of inertia of the inverter. The parameter J can make the inverter's active power and frequency response show inertia; D p is the damping coefficient; U0 and U are the rated phase voltage RMS value and the actual phase voltage RMS value of the capacitor respectively; D q is the voltage regulation coefficient, through D q The droop characteristic of the reactive loop is simulated; K is the excitation regulation coefficient; s is the Laplace operator.

[0077] After that, the reference voltage amplitude V ref and the reference voltage phase θ ref Input to Figure 3 The voltage command calculation unit in the circuit obtains the corresponding reference voltage u ref Specifically, the reference voltage amplitude V ref and the reference voltage phase θ ref It is expanded into the reference voltage in the three-phase abc coordinate system, and then converted into the reference voltage in the two-phase αβ coordinate system through Clark transformation to calculate the reference voltage instruction. The specific expression is as follows:

[0078] u refa =V ref sin(θ ref )

[0079]

[0080] In the formula, u refa 、u refb and u refc The reference voltage u ref a, b, c components; u refα and u refβ The reference voltage u ref The α and β components of .

[0081] S250: Add the difference between the inverter-side current and the grid-side current to a preset grid harmonic compensation current instruction to obtain a harmonic control parameter.

[0082] Among them, the harmonic control parameters can be understood as the input information of the proportional resonant controller, and the harmonic compensation and power quality management capabilities of the power grid can be adaptively adjusted through the harmonic control parameters.

[0083] In the embodiment of the present invention, the inverter side current i1 and the grid side current i2 can be subtracted and then compared with the preset grid harmonic compensation current instruction i inject.h The result of the addition is used as a harmonic control parameter so that the harmonic control parameter can be used to perform harmonic control on the inverter later.

[0084] S260: Use the harmonic control parameter as an input of a preconfigured proportional resonant controller to generate a harmonic portion instruction of the inverter inductor current.

[0085] Figure 5 This is a control block diagram of the power quality management module provided in the second embodiment of the present invention. Figure 5 As shown, the power quality management module is used to realize the capacitor voltage u output by the inverter c The amplitude and phase are the same as the given reference voltage u ref Keep consistent, specifically including the following three parts: voltage loop controller, proportional resonant controller and current loop controller. Among them, G pwm is the equivalent transfer function of the inherent delay link of the system; G u is the transfer function of the voltage loop controller; G i is the transfer function of the current loop controller; G HC is the transfer function of the proportional resonant controller.

[0086] Specifically, the harmonic control parameters determined above can be used as inputs of a proportional resonant controller to generate a harmonic part command i of the inverter inductor current. ref.h , where the transfer function of the proportional resonant controller is G HC It is expressed as follows:

[0087]

[0088] Among them, K pi Represents proportional gain; K rh represents the gain at the hth harmonic; ω hi Used to adjust frequency adaptability; represents the compensation phase angle; h represents the number of harmonics that need to be suppressed; s represents the Laplace operator; ω0 represents the rated frequency.

[0089] In order to ensure that the system is ref The proportional resonant controller is introduced into the voltage outer loop control to improve the reference voltage u by using the high gain characteristic of the proportional resonant controller at the harmonic frequency.ref The control performance enables the system to effectively track the reference voltage u ref , to achieve effective compensation for grid harmonics and thus improve the power quality of the grid.

[0090] S270 , performing voltage outer loop control based on the capacitor voltage and the reference voltage to obtain a reference current.

[0091] like Figure 5 As shown, in the embodiment of the present invention, the capacitor voltage u c and reference voltage u ref Input to the voltage loop controller of the power quality management module to determine the corresponding reference current i ref The voltage controller can be a proportional controller, which is used to adjust the voltage according to the reference voltage u ref , the capacitor voltage u of the inverter output c Perform voltage outer loop control and track the reference voltage u ref .

[0092] S280, performing current inner loop control based on the reference current, the inverter side current and the harmonic wave part instruction to obtain the target control parameters.

[0093] like Figure 5 As shown, in the embodiment of the present invention, the reference current i ref , inverter side current i1 and harmonic part instruction i ref.h The current loop controller is input into the current inner loop controller of the power quality management module, and the corresponding target control parameters are output after the current inner loop control; among them, the current loop controller can adopt a proportional controller to track the reference current i ref , and output the corresponding target control parameter; the target control parameter can be understood as a parameter used to control the duty cycle of the inverter.

[0094] S290, determining a pulse width modulation signal after the target control parameter is modulated by the space vector, and controlling the working state of the switch tube according to the pulse width modulation signal.

[0095] Among them, space vector modulation (Space Vector Pulse Width Modulation, SVPWM) is a common modulation method in three-phase inverter circuits. It generates a pulse width modulation signal (PWM modulation signal) to control the working state of the inverter switch tube, that is, turn on or off, thereby controlling the inverter output and a given reference voltage u ref The capacitor voltage u remains consistent in both amplitude and phase c .

[0096] like Figure 3As shown, in the embodiment of the present invention, the above-determined target control parameters can be input into the PWM modulation module, and the corresponding PWM modulation signals can be generated after space vector modulation, so as to realize the control of the switch tube of the inverter. It can be understood that the duty cycle of the PWM modulation signals corresponding to different target control parameters is different, and the conduction or cutoff of the inverter switch tube is controlled by the PWM modulation signals with different duty cycles, so as to realize the capacitor voltage u output by the inverter c The amplitude and phase are the same as the given reference voltage u ref Be consistent.

[0097] The technical solution of the embodiment of the present invention determines a reference voltage based on the grid-side current, capacitor voltage, preset active power and preset reactive power, and by simulating the rotor motion and excitation characteristics of the synchronous generator, and uses the reference voltage to realize basic grid-type inverter control; generates a harmonic part instruction of the inverter inductor current through sampling feedback of the existing inverter side current and the grid side current, and a preset grid harmonic compensation current instruction required for power quality management, and further obtains the corresponding target control parameters through voltage and current dual closed-loop control, and then controls the working state of the inverter switch tube according to the target control parameters. It realizes the seamless integration of power quality management functions in the existing grid-forming inverter topology structure, can control the inverter to achieve grid-forming control while realizing the reuse of power quality management functions, can receive grid harmonic compensation current instructions in distributed distribution network stations and power supply areas to compensate for the harmonics in the existing power grid and thus improve the power quality of the grid; uses the surplus capacity of the inverter to manage the power quality of the grid, thereby improving the utilization rate of inverter resources; at the same time, it has a wide range of application scenarios, and can seamlessly integrate the power quality management function into each distributed energy power supply area and station, and use distributed inverters to manage grid harmonic problems.

[0098] Embodiment 3

[0099] Figure 6 This is a schematic diagram of the structure of a power quality management function multiplexing control device for a grid-type inverter provided in the third embodiment of the present invention. Figure 6 As shown, the device comprises:

[0100] The parameter acquisition module 31 is used to acquire the real-time operating parameters of the inverter; wherein the real-time operating parameters at least include: the inverter side current, the grid side current and the capacitor voltage of the filter capacitor;

[0101] A reference voltage determination module 32, used to determine a reference voltage corresponding to the inverter according to the grid-side current, capacitor voltage and preset operating parameters;

[0102] A harmonic part instruction generating module 33, used to generate a harmonic part instruction of the inverter inductor current based on a preset power grid harmonic compensation current instruction, an inverter side current and a grid side current;

[0103] A target control parameter determination module 34 is used to determine the target control parameter according to the inverter side current, capacitor voltage, reference voltage and harmonic part instructions;

[0104] The inverter control module 35 is used to control the switch tube of the inverter according to the target control parameter.

[0105] The technical solution of the embodiment of the present invention, on the basis of the basic meshing control based on a determined reference voltage, adds an additional input of a preset grid harmonic compensation current instruction required for power quality management to generate a corresponding target control parameter, and then controls the switch tube of the inverter according to the target control parameter, thereby solving the problem of multiplexing the power quality management function on the meshing control architecture, and realizing the seamless integration of the power quality management function in the existing meshing inverter topology structure, which can control the inverter to realize meshing control while realizing the multiplexing of the power quality management function; by injecting suitable harmonics into the power grid to compensate for the harmonics in the existing power grid and thus improve the power quality of the power grid, the utilization rate of the inverter resources is improved at the same time, and the application scenarios are wide.

[0106] Further, based on the above-mentioned embodiment of the invention, the reference voltage determination module 32 includes:

[0107] A coordinate conversion unit, used for performing Clarke transformation on the grid-side current and capacitor voltage in the three-phase coordinate system to obtain a target grid-side current and target capacitor voltage in the two-phase coordinate system;

[0108] A power calculation unit, used to perform power calculation based on a target grid-side current and a target capacitor voltage to obtain instantaneous active power and instantaneous reactive power output by the inverter;

[0109] The reference voltage determination unit is used to determine the reference voltage phase and reference voltage amplitude corresponding to the instantaneous active power and instantaneous reactive power based on the preset active power and preset reactive power and through any meshing algorithm, and synthesize the reference voltage phase and the reference voltage amplitude into a reference voltage.

[0110] Further, based on the above-mentioned embodiment of the invention, the harmonic part instruction generating module 33 includes:

[0111] A harmonic control parameter determination unit, used for adding the difference between the inverter side current and the grid side current to a preset grid harmonic compensation current instruction to obtain a harmonic control parameter;

[0112] The harmonic part instruction generating unit is used for taking the harmonic control parameter as the input of the pre-configured proportional resonant controller to generate the harmonic part instruction of the inverter inductor current.

[0113] Further, based on the above-mentioned embodiment of the invention, the target control parameter determination module 34 includes:

[0114] A voltage outer loop control unit, used for performing voltage outer loop control based on capacitor voltage and reference voltage to obtain a reference current;

[0115] The current inner loop control unit is used to perform current inner loop control based on the reference current, the inverter side current and the harmonic part instruction to obtain the target control parameters.

[0116] Further, based on the above-mentioned embodiment of the invention, the inverter control module 35 includes:

[0117] The inverter control unit is used to determine the pulse width modulation signal after the target control parameter is modulated by the space vector, and control the working state of the switch tube according to the pulse width modulation signal.

[0118] Further, based on the above-mentioned embodiment of the invention, the power calculation unit is specifically used for:

[0119] The instantaneous active power and instantaneous reactive power are determined by the following formula;

[0120] P out =u cα i 2α +u cβ i 2β ;

[0121] Q out =u cβ i 2α -u cα i 2β ;

[0122] Among them, P out Indicates instantaneous active power; Q out Represents instantaneous reactive power; i 2α and i 2β They represent the α and β components of the target grid-side current respectively; u cα and u cβ They represent the α and β components of the target capacitor voltage respectively.

[0123] Further, based on the above-mentioned embodiment of the invention, the transfer function of the proportional resonant controller is expressed as:

[0124]

[0125] Among them, Kpi Represents proportional gain; K rh represents the gain at the hth harmonic; ω hi Used to adjust frequency adaptability; represents the compensation phase angle; h represents the number of harmonics that need to be suppressed; s represents the Laplace operator; ω0 represents the rated frequency.

[0126] The power quality management function multiplexing control device of the grid-type inverter provided in the embodiment of the present invention can execute the power quality management function multiplexing control method of the grid-type inverter provided in any embodiment of the present invention, and has the functional modules and beneficial effects corresponding to the execution method.

[0127] Embodiment 4

[0128] Figure 7 A schematic diagram of the structure of an electronic device 40 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0129] like Figure 7 As shown, the electronic device 40 includes at least one processor 41, and a memory connected to the at least one processor 41, such as a read-only memory (ROM) 42, a random access memory (RAM) 43, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 41 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 42 or the computer program loaded from the storage unit 48 to the random access memory (RAM) 43. In the RAM 43, various programs and data required for the operation of the electronic device 40 can also be stored. The processor 41, the ROM 42, and the RAM 43 are connected to each other through a bus 44. An input / output (I / O) interface 45 is also connected to the bus 44.

[0130] A number of components in the electronic device 40 are connected to the I / O interface 45, including: an input unit 46, such as a keyboard, a mouse, etc.; an output unit 47, such as various types of displays, speakers, etc.; a storage unit 48, such as a disk, an optical disk, etc.; and a communication unit 49, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 49 allows the electronic device 40 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0131] The processor 41 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 41 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The processor 41 executes the various methods and processes described above, such as a power quality management function multiplexing control method for a grid-type inverter.

[0132] In some embodiments, the power quality management function multiplexing control method of the grid-type inverter can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 48. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 40 via the ROM 42 and / or the communication unit 49. When the computer program is loaded into the RAM 43 and executed by the processor 41, one or more steps of the power quality management function multiplexing control method of the grid-type inverter described above can be performed. Alternatively, in other embodiments, the processor 41 can be configured to execute the power quality management function multiplexing control method of the grid-type inverter in any other appropriate manner (for example, by means of firmware).

[0133] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0134] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0135] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0136] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0137] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0138] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0139] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0140] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling the power quality management function of a grid-connected inverter, characterized in that: The method comprises: Acquire real-time operating parameters of the inverter; wherein the real-time operating parameters include at least: inverter-side current, grid-side current and capacitor voltage of the filter capacitor; Determining a reference voltage corresponding to the inverter according to the grid-side current, the capacitor voltage and preset operating parameters; Based on a preset grid harmonic compensation current instruction, the inverter-side current and the grid-side current, a harmonic part instruction of the inverter inductor current is generated; determining a target control parameter according to the inverter side current, the capacitor voltage, the reference voltage and the harmonic part instruction; The switch tube of the inverter is controlled according to the target control parameter.

2. The method according to claim 1, characterized in that The determining, according to the grid-side current, the capacitor voltage and preset operating parameters, a reference voltage corresponding to the inverter includes: Performing Clarke transformation on the grid-side current and the capacitor voltage in the three-phase coordinate system to obtain a target grid-side current and a target capacitor voltage in the two-phase coordinate system; Performing power calculation based on the target grid-side current and the target capacitor voltage to obtain instantaneous active power and instantaneous reactive power output by the inverter; Based on the preset active power and the preset reactive power and through any meshing algorithm, the reference voltage phase and the reference voltage amplitude corresponding to the instantaneous active power and the instantaneous reactive power are determined, and the reference voltage phase and the reference voltage amplitude are synthesized into the reference voltage.

3. The method according to claim 1, characterized in that The generating of the harmonic part instruction of the inverter inductor current based on the preset grid harmonic compensation current instruction, the inverter side current and the grid side current comprises: Adding the difference between the inverter-side current and the grid-side current to the preset grid harmonic compensation current instruction to obtain a harmonic control parameter; The harmonic control parameter is used as an input of a preconfigured proportional resonant controller to generate a harmonic portion command of the inverter inductor current.

4. The method according to claim 1, characterized in that: The determining of the target control parameter according to the inverter side current, the capacitor voltage, the reference voltage and the harmonic part instruction comprises: Perform voltage outer loop control based on the capacitor voltage and the reference voltage to obtain a reference current; The target control parameter is obtained by performing current inner loop control based on the reference current, the inverter side current and the harmonic part instruction.

5. The method according to claim 1, characterized in that The controlling the switch tube of the inverter according to the target control parameter includes: A pulse width modulation signal after the target control parameter is space vector modulated is determined, and the working state of the switch tube is controlled according to the pulse width modulation signal.

6. The method according to claim 2, characterized in that The power calculation is performed based on the target grid-side current and the target capacitor voltage to obtain the instantaneous active power and instantaneous reactive power output by the inverter, including: The instantaneous active power and the instantaneous reactive power are determined by the following formula; P out =in cα and 2α +in cβ and 2β ; Q out =u cβ i 2α -u cα i 2β ; Among them, P out Represents the instantaneous active power; Q out represents the instantaneous reactive power; i 2α and i 2β Respectively represent the α and β components of the target grid-side current; u cα and u cβ They respectively represent the α and β components of the target capacitor voltage.

7. The method according to claim 3, characterized in that The transfer function of the proportional resonant controller is expressed as: Among them, K pi Represents proportional gain; K rh represents the gain at the hth harmonic; ω hi Used to adjust frequency adaptability; represents the compensation phase angle; h represents the number of harmonics that need to be suppressed; s represents the Laplace operator; ω0 represents the rated frequency.

8. A power quality management function multiplexing control device for a grid-connected inverter, characterized in that: The device comprises: A parameter acquisition module, used to acquire real-time operating parameters of the inverter; wherein the real-time operating parameters at least include: inverter side current, grid side current and capacitor voltage of the filter capacitor; A reference voltage determination module, used to determine a reference voltage corresponding to the inverter according to the grid-side current, the capacitor voltage and preset operating parameters; A harmonic part instruction generation module, used for generating a harmonic part instruction of the inverter inductor current based on a preset power grid harmonic compensation current instruction, the inverter side current and the grid side current; A target control parameter determination module, used to determine the target control parameter according to the inverter side current, the capacitor voltage, the reference voltage and the harmonic part instruction; The inverter control module is used to control the switch tube of the inverter according to the target control parameter.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the power quality management function multiplexing control method of the grid-connected inverter described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the power quality management function multiplexing control method of a grid-connected inverter as described in any one of claims 1 to 7 when executed.

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