Control method, controller, compensation device, converter, storage medium and device

Abstract

The present application discloses a control method, a controller, a disturbance compensation device, an energy storage converter, a computer-readable storage medium and a computer device of a converter, and relates to the technical field of converters. The control method comprises: obtaining a voltage model of a DC bus of the converter, the voltage model is determined according to the active power connected to the converter, the power loss of the DC bus and the output power of the DC bus; compensating for the disturbance of the voltage model according to a disturbance state observer, the disturbance state observer is determined according to the voltage model. The control method can construct a disturbance state observer according to the DC bus voltage model, and compensate for the disturbance of the voltage model through the disturbance state observer, so as to reduce or avoid the influence of various disturbances in the DC bus voltage model on the DC bus voltage, so that the voltage of the DC bus is controlled within a reasonable range, thereby improving the reliability of the converter.

Description

Technical Field

[0001] The present application relates to the technical field of converters, and more specifically, to a control method, a controller, a disturbance compensation device, an energy storage converter, a computer-readable storage medium, and a computer device for a converter. Background Art

[0002] For the converters widely used in industry, if the DC bus voltage of the converter is too high, it will trigger the protection action of the converter, and if the DC bus voltage is too low, the power conversion efficiency of the converter will be reduced. Therefore, it is necessary to control the voltage of the DC bus within a reasonable range.

[0003] However, due to the existence of various disturbances in the DC bus voltage model (such as grid voltage fluctuations and environmental uncertainties), it is difficult to control the DC bus voltage within a reasonable range. Summary of the invention

[0004] Embodiments of the present application provide a control method for a converter, a controller, a disturbance compensation device, an energy storage converter, a computer-readable storage medium, and a computer device.

[0005] The control method of the converter provided in the embodiment of the present application includes: obtaining a voltage model of the DC bus of the converter, wherein the voltage model is determined based on the active power connected to the converter, the power loss of the DC bus and the output power of the DC bus; and compensating for the disturbance of the voltage model based on a disturbance state observer, wherein the disturbance state observer is determined based on the voltage model.

[0006] In this way, the control method provided in the embodiment of the present application can construct a disturbance state observer based on the DC bus voltage model, and compensate for the disturbance of the voltage model through the disturbance state observer, thereby reducing or avoiding the influence of various disturbances in the DC bus voltage model on the DC bus voltage, so that the voltage of the DC bus is controlled within a reasonable range, thereby improving the reliability of the converter.

[0007] In some embodiments, compensating for the disturbance of the voltage model according to a disturbance state observer includes: compensating for the external disturbance of the voltage model caused by the loss power and the internal disturbance of the voltage model caused by the output power according to the disturbance state observer.

[0008] In this way, the disturbance state observer can compensate for the external disturbance of the voltage model caused by the loss power and the internal disturbance of the voltage model caused by the output power, reduce or avoid the influence of various disturbances in the DC bus voltage model on the DC bus voltage, so that the voltage of the DC bus can be controlled within a reasonable range, thereby improving the reliability of the converter.

[0009] In some embodiments, constructing a disturbance state observer according to the voltage model includes: determining a nominal model according to the voltage model and a nominal capacitance value of the DC bus; and constructing the disturbance state observer according to the nominal model and a model of a low-pass filter.

[0010] In this way, a disturbance state observer can be constructed based on the nominal model and the low-pass filter model to estimate the internal disturbance and external disturbance of the voltage model.

[0011] In certain embodiments, within a desired bandwidth of the low-pass filter, the disturbance state observer is configured to compensate for the external disturbance and the internal disturbance to make the voltage model consistent with the nominal model.

[0012] In this way, within the expected bandwidth of the low-pass filter, the disturbance state observer can eliminate the influence of external disturbances and internal disturbances on the output voltage model of the DC bus, so that the voltage model is consistent with the nominal model.

[0013] In certain implementations, the disturbance state observer is configured to compensate for the external disturbance outside a desired bandwidth of the low-pass filter and within a control bandwidth of the low-pass filter.

[0014] In some embodiments, the converter includes a voltage controller of the DC bus, and the desired bandwidth is determined according to a sampling frequency of the voltage controller and the Nyquist theorem.

[0015] In some embodiments, the method includes: adjusting the active power and the output power according to the voltage model to make the voltage value of the DC bus constant.

[0016] In this way, by adjusting the active power and the output power according to the voltage model, the voltage value of the DC bus can be kept constant to ensure that the energy storage converter can operate stably.

[0017] In certain embodiments, the method includes: constructing an outer loop controller for the DC bus voltage, wherein the outer loop controller is a proportional-integral controller.

[0018] In some embodiments, the control method is used for a grid-following converter.

[0019] An embodiment of the present application further provides a controller, which includes a memory and a processor, wherein the memory is configured to store a computer program, and the processor implements the above control method when executing the computer program.

[0020] In certain embodiments, when executing a computer program, the processor can obtain a voltage model of the DC bus of the converter, where the voltage model is determined based on the active power connected to the converter, the power loss of the DC bus, and the output power of the DC bus; construct a disturbance state observer based on the voltage model; and compensate for external disturbances of the voltage model caused by the power loss and internal disturbances of the voltage model caused by the output power based on the disturbance state observer.

[0021] In certain embodiments, when executing the computer program, the processor can determine the nominal model according to the voltage model and the nominal capacitance value of the DC bus; and construct a disturbance state observer according to the nominal model and the model of the low-pass filter.

[0022] The embodiment of the present application provides a disturbance compensation device. The disturbance compensation device includes an acquisition module, a construction module and a compensation module. The acquisition module is configured to acquire a voltage model of a DC bus of a converter, and the voltage model is determined according to the active power connected to the converter, the power loss of the DC bus and the output power of the DC bus. The construction module is configured to construct a disturbance state observer according to the voltage model. The compensation module is configured to compensate for the external disturbance of the voltage model caused by the power loss and the internal disturbance of the voltage model caused by the output power according to the disturbance state observer, so as to control the voltage of the DC bus.

[0023] In some implementations, the construction module may determine the nominal model according to the voltage model and the nominal capacitance value of the DC bus, and the construction module may also construct the nominal model and the model of the low-pass filter to construct a disturbance state observer.

[0024] In some embodiments, the acquisition module can also acquire a predetermined sampling frequency and a phase margin, and the construction module can also determine an outer loop controller model of the DC bus voltage based on the predetermined sampling frequency and the phase margin, and construct an outer loop controller of the DC bus voltage based on the outer loop controller model.

[0025] The embodiments of the present application also provide an energy storage converter, which includes the controller or disturbance compensation device of the embodiments of the present application.

[0026] In certain embodiments, the energy storage converter comprises a grid-connected converter.

[0027] The computer-readable storage medium provided in the embodiments of the present application stores a computer program, and when the computer program is executed by one or more processors, the control method of the above-mentioned embodiments is implemented.

[0028] The computer device provided in the embodiment of the present application includes a memory and a processor, the memory is configured to store a computer program, and the processor implements the control method of the above embodiment when executing the computer program.

[0029] The embodiment of the present application provides a control method, a controller, a disturbance compensation device, an energy storage converter, a computer-readable storage medium and a computer device for a converter. The control method includes: obtaining a voltage model of a DC bus of the converter, the voltage model is determined according to the active power connected to the converter, the power loss of the DC bus and the output power of the DC bus; compensating for the disturbance of the voltage model according to a disturbance state observer, the disturbance state observer is determined according to the voltage model.

[0030] The control method provided in the embodiment of the present application can construct a disturbance state observer according to the DC bus voltage model, and compensate for the disturbance of the DC bus voltage model through the disturbance state observer, thereby reducing or avoiding the influence of various disturbances in the DC bus voltage model on the DC bus voltage, so that the voltage of the DC bus is controlled within a reasonable range, thereby improving the reliability of the converter.

[0031] The control method of the implementation mode of the present application can also compensate for the internal and external disturbances of the voltage model of the DC bus by improving the control strategy of the grid-following converter, so as to control the voltage of the DC bus of the grid-following converter to be constant, thereby improving the ability and stability of the grid-following converter to cope with grid disturbances.

[0032] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0034] Figure 1 It is a first flow chart of the control method of the implementation mode of the present application;

[0035] Figure 2 is a first schematic diagram of an energy storage converter according to an embodiment of the present application;

[0036] Figure 3 is a second schematic diagram of an energy storage converter according to an embodiment of the present application;

[0037] Figure 4 is a schematic diagram of a control loop of an embodiment of the present application;

[0038] Figure 5is a second flow chart of the control method of the implementation mode of the present application;

[0039] Figure 6 It is an open-loop Bode diagram of the DC bus voltage in the implementation mode of the present application. DETAILED DESCRIPTION

[0040] The embodiments of the present application are described in detail below, and the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0041] For the converters widely used in industry, if the DC bus voltage of the converter is too high, it will trigger the protection action of the converter, and if the DC bus voltage is too low, the power conversion efficiency of the converter will be reduced. Therefore, it is necessary to control the voltage of the DC bus within a reasonable range.

[0042] However, due to the existence of various disturbances in the DC bus voltage model (such as grid voltage fluctuations and environmental uncertainties), it is difficult to control the DC bus voltage within a reasonable range.

[0043] Reference Figure 1 , the embodiment of the present application provides a control method of a converter. The control method may include:

[0044] Step 01: Obtain a voltage model of the DC bus of the converter. The voltage model is determined according to the active power connected to the converter, the power loss of the DC bus, and the output power of the DC bus;

[0045] Step 02: Compensate for the disturbance of the voltage model according to the disturbance state observer, which is determined according to the voltage model.

[0046] Reference Figure 2 , an embodiment of the present application provides a controller 10. The control method of the embodiment of the present application can be implemented by the controller 10 of the embodiment of the present application. Of course, the control method can also be implemented by other devices or equipment, and is not limited to being implemented by the controller 10. The controller 10 may not be dedicated to implementing the control method of the embodiment of the present application, but can implement other functions and methods. Specifically, the controller 10 may include a memory and a processor. The memory is configured to store a computer program, and the processor can implement the above steps 01 and 02 when executing the computer program.

[0047] Reference Figure 2, the embodiment of the present application also provides a disturbance compensation device 20. The disturbance compensation device 20 may include an acquisition module, a construction module and a compensation module. Among them, the acquisition module is configured to acquire a voltage model of the DC bus of the converter, and the voltage model is determined according to the active power connected to the converter, the loss power of the DC bus and the output power of the DC bus. The construction module is configured to construct a disturbance state observer according to the voltage model. The compensation module is configured to compensate for the external disturbance of the voltage model caused by the loss power and the internal disturbance of the voltage model caused by the output power according to the disturbance state observer.

[0048] Reference Figure 2 The embodiment of the present application also provides an energy storage converter 100. The energy storage converter 100 may include a controller 10 provided in the embodiment of the present application. The controller 10 may implement the control method provided in the embodiment of the present application to control the voltage of the DC bus. The energy storage converter 100 may also include a disturbance compensation device 20 provided in the embodiment of the present application. The disturbance compensation device 20 may compensate for the internal disturbance and external disturbance of the voltage model of the DC bus to control the voltage of the DC bus.

[0049] The energy storage converter 100 may include a converter connection circuit 30, a first side of which may be connected to a power grid via a transformer, and a second side of which may be connected to a load. The converter connection circuit 30 may include a voltage conversion circuit, an inverter circuit, and a rectifier circuit, wherein the rectifier converts AC power into DC power, and the inverter converts the stored DC power into AC power to meet the power supply requirements of the connected power grid or load.

[0050] The controller 10 or the disturbance compensation device 20 can control the working mode and parameter setting of the converter connection circuit 30 to compensate for the internal disturbance and external disturbance of the voltage model of the DC bus to control the voltage of the DC bus.

[0051] Specifically, the topological structure of the converter connection circuit 30 can refer to Figure 3 , the converter connection circuit 30 may include an AC / DC module (alternating current / direct current module), a DC / DC module (direct current / direct current module) and a DC / AC module (direct current-alternating current module). The AC / DC module may be set as a rectifier circuit, and convert the connected AC voltage into a DC output after rectification. The DC / DC module may be set as a DC transformer circuit, and the DC / DC module may transform the connected DC voltage and output the transformed DC voltage. The DC / AC module may be set as an inverter circuit, and convert the connected DC voltage into an AC voltage after inversion for output.

[0052] The converter connection circuit 30 may further include a bus capacitor C0 and an inductor Lgrid. The bus capacitor C0 may be set as a capacitive element of the DC bus 31. The first side of the AC / DC module may be connected to the grid through the inductor Lgrid, and the second side of the AC / DC module may be connected to the bus capacitor C0. The AC / DC module may convert the AC voltage connected to the first side into a DC voltage and provide it to the bus capacitor C0.

[0053] The first side of the DC / DC module can be connected to the battery, and the second side of the DC / DC module can be connected to the DC bus 31. The DC / DC module can provide the battery voltage to the DC bus 31, and enable the AC / DC module to convert the voltage of the DC bus 31 into corresponding AC power and provide it to the grid. The DC / DC module can also provide the voltage of the DC bus 31 to the battery.

[0054] The first side of the AC / DC module can be connected to the DC bus 31, or it can be connected to the second side of the DC / DC module. The AC / DC module can convert the voltage provided by the DC bus 31 into an AC voltage and provide it to the load. The AC / DC module can also convert the voltage provided by the battery into an AC voltage and provide it to the load.

[0055] The power connected to the DC bus 31 can be set to power , the output power of the DC bus 31 can be set to power The power loss of the DC bus 31 can be set as . Can be set to power Subtract power The power connected to the first side of the AC / DC module can be set to power Without considering the conversion loss of the AC / DC module, the power Can be set to power equal.

[0056] The voltage connected to the DC bus 31 can be set to V DC , the capacitance value of the bus capacitor C0 can be set to C, and the DC bus voltage 31 can be expressed as: .

[0057] The active power connected to the first side of the inductor device Lgrid can be set to power , the active power output from the second side of the inductor device Lgrid can be set to Since the first side of the AC / DC module can be connected to the grid through the inductor Lgrid, the active power of the grid connected to the converter can be set to power Without considering the conversion loss of the inductor Lgrid and the conversion loss of the AC / DC module, the power Can also be set to power Equal, the DC bus 31 voltage can be expressed as: .

[0058] The transfer function model of the DC bus 31 voltage can be expressed as: .

[0059] In some embodiments, step 02: compensating for the disturbance of the voltage model according to the disturbance state observer may include: compensating for the external disturbance of the voltage model caused by the loss power and the internal disturbance of the voltage model caused by the output power according to the disturbance state observer.

[0060] In step 01, the voltage model of the DC bus 31 of the converter can be set as , the voltage of the DC bus 31 can be set to V DC , V DC The active power connected to the converter can be , power loss of DC bus 31 and the output power of the DC bus 31 Sure.

[0061] The output input can be set as the transfer function of the DC bus 31 voltage, active power The control input and output power can be set as transfer functions. and power loss Can be set as a disturbance of the transfer function model. It is generated based on the loss inside the DC bus 31. The power loss It can be set as an internal disturbance of the voltage model of the DC bus 31. Output power is the output power of DC bus 31 to the outside, output power It can be set as an external disturbance of the voltage model of the DC bus 31.

[0062] In step 02, a disturbance state observer can be used to estimate internal disturbances and external disturbances of the voltage model.

[0063] A state observer is a dynamic system that estimates the state variables based on the measured values ​​of the system's external variables (input variables and output variables), also known as a state reconstructor. A disturbance state observer can be set as an extended state observer (ESO), which can estimate the internal state of the system and can also estimate and compensate for unknown disturbances and uncertainties in the system in real time.

[0064] by Figure 4 For example, active power Can be set as control input of transfer function , output power An external disturbance of the voltage model of the DC bus 31 can be set , power loss The internal disturbance generated and the transfer function The disturbance observer (DOB) can predict the external disturbance d and the power loss. The internal disturbance generated. and The constructed disturbance state observer can feed back the compensation value to the control input of the transfer function , to achieve the output value The model of the DC bus 31 voltage can be compensated online according to the estimated value of the state variable determined by the disturbance state observer, ensuring that the model of the DC bus 31 voltage is not affected by internal and external disturbances, thereby improving the reliability of controlling the DC bus 31 voltage.

[0065] by Figure 4 For example, the disturbance state observer can feed back the compensation value to the control input of the transfer function , so that the output value of the transfer function Not affected by internal and external disturbances.

[0066] It can be understood that the control method provided in the embodiment of the present application can construct a disturbance state observer based on the DC bus 31 voltage model, and compensate for the disturbances caused by the loss power and the output power through the disturbance state observer, thereby reducing or avoiding the influence of various disturbances in the DC bus 31 voltage model on the DC bus 31 voltage, so that the voltage of the DC bus 31 is controlled within a reasonable range, thereby improving the reliability of the converter.

[0067] In some embodiments, the control method may further include:

[0068] Step 011: determining a nominal model according to the voltage model and the nominal capacitance value of the DC bus 31;

[0069] Step 012: Construct a disturbance state observer based on the nominal model and the low-pass filter model.

[0070] In some implementations, the processor may implement the above steps 011 to 012 when executing a computer program.

[0071] In some embodiments, the construction module may determine the nominal model according to the voltage model and the nominal capacitance value of the DC bus 31 , and the construction module may also construct a disturbance state observer by constructing the nominal model and a low-pass filter model.

[0072] Specifically, in step 011, the nominal capacitance value of the DC bus 31 can be set to , the nominal model can be set as The actual capacitance value of the DC bus 31 can be set to C, and the actual transfer function is Can be set to , the disturbance model corresponding to the internal disturbance can be set as , .

[0073] When the actual capacitance value of the DC bus 31 is the nominal capacitance value, the disturbance model corresponding to the internal disturbance is =0, at this time, it can be considered that the internal disturbance influence in the DC bus 31 voltage model is eliminated.

[0074] In step 012, the model of the low-pass filter can be set as , .

[0075] in, The frequency value of the input signal can be set as the low-pass filter. It can be set according to the desired bandwidth of the low-pass filter, It can be set according to the control bandwidth of the low-pass filter. and The constructed disturbance state observer can feed back the compensation value to the control input of the transfer function , so that the output It can be expressed as .

[0076] because , .in, It can be expressed as the effect of internal disturbance on the output voltage of DC bus 31, It can be expressed as the influence of external disturbance on the output voltage of DC bus 31.

[0077] In this way, a disturbance state observer can be constructed based on the nominal model and the low-pass filter model to estimate the internal disturbance and external disturbance of the voltage model.

[0078] In certain embodiments, the disturbance state observer is configured to compensate for external disturbances and internal disturbances within a desired bandwidth of the low-pass filter to make the voltage model consistent with the nominal model.

[0079] Specifically, the desired bandwidth of the low-pass filter can be set as Within the desired bandwidth of the low-pass filter, =1, then , the disturbance state observer can compensate for external disturbances and internal disturbances, and the output value According to the nominal model Sure, as well as The output value will not be have an impact.

[0080] In this way, within the desired bandwidth of the low-pass filter, the disturbance state observer can eliminate the influence of external disturbances and internal disturbances on the output voltage model of the DC bus 31, so that the voltage model is consistent with the nominal model.

[0081] In certain embodiments, the disturbance state observer is configured to compensate for external disturbances outside a desired bandwidth of the low pass filter and within a control bandwidth of the low pass filter.

[0082] Specifically, the low-pass filter outside the desired bandwidth and within the control bandwidth can be set as ,exist In the case of =0, then , the disturbance state observer can compensate for the internal disturbance, The output value will not be have an impact.

[0083] The voltage closed-loop control function of the DC bus can be set as: .

[0084] Within the desired bandwidth of the low-pass filter, In this way, it can be ensured that the uncertainty and disturbance of the closed-loop voltage control function of the DC bus 31 are offset within the desired bandwidth of the low-pass filter.

[0085] In some embodiments, the converter includes a voltage controller of the DC bus 31 , and the desired bandwidth is determined according to a sampling frequency of the voltage controller and the Nyquist theorem.

[0086] Specifically, for the desired bandwidth of the low-pass filter ( ), the design principle should follow the rule that the highest expected bandwidth of the low-pass filter should not exceed the Nyquist frequency.

[0087] by Figure 4 For example, the voltage controller of the DC bus 31 can control the input value of the transfer function , the sampling frequency of the voltage controller can be set to Fs, the corresponding Nyquist frequency bandwidth can be set to 2*2π*Fs, and the expected bandwidth of the low-pass filter ( ) can be set to be less than 2*2π*Fs.

[0088] For example, the sampling frequency Fs of the controller 10 can be set to 10 kHz, and the desired bandwidth of the low-pass filter ( ) can be set to 10000rad / s.

[0089] In some embodiments, the method may further include: adjusting the active power and the output power according to the voltage model so as to keep the voltage value of the DC bus 31 constant.

[0090] Specifically, the voltage of the DC bus 31 can be expressed as Without considering the power consumption of DC bus 31 In the case of .

[0091] According to the active power Adjust output power , or according to the output power Active power regulation , so that the output power Active Power Consistent, =0, at this time, the voltage value of the DC bus 31 will not change with time, and the voltage value of the DC bus 31 can be in a constant state.

[0092] In this way, by adjusting the active power and the output power according to the voltage model, the voltage value of the DC bus 31 can be kept constant, so as to ensure that the energy storage converter can operate stably.

[0093] Reference Figure 5 In some embodiments, the method may further include: Step 03: constructing an outer loop controller of the DC bus 31 voltage.

[0094] Step 03 may include: Step 031: obtaining a predetermined sampling frequency and a phase margin;

[0095] Step 032: Determine the outer loop controller model of the DC bus 31 voltage according to the predetermined sampling frequency and phase margin.

[0096] In some embodiments, the processor may implement the above steps 031 and 032 when executing a computer program.

[0097] In some embodiments, the acquisition module can also acquire a predetermined sampling frequency and a phase margin, and the construction module can also determine an outer loop controller model of the DC bus 31 voltage based on the predetermined sampling frequency and the phase margin, and construct an outer loop controller of the DC bus 31 voltage based on the outer loop controller model.

[0098] Specifically, in step 031, the predetermined sampling frequency can be set to the sampling frequency Fs of the outer loop controller of the DC bus 31 voltage, and the bandwidth of the current closed loop It can be set to 2π*Fs / 10. To ensure that the phase delay caused by the current closed loop can be ignored, the voltage loop bandwidth Should be sufficiently lower than the bandwidth of the current closed loop , such as the voltage loop bandwidth Can be taken / 10.

[0099] For example, the sampling frequency Fs of the controller 10 can be set to 10 kHz, and the bandwidth of the current closed loop The voltage loop bandwidth can be 6800rad / s. It can be taken as 700rad / s.

[0100] Phase margin refers to the difference between the phase angle of the system open-loop frequency response and -180 degrees when the system gain is 1 (i.e. 0dB). The larger the phase margin, the better the relative stability of the system. The model of the outer loop controller can set a phase margin of 30 to 60 degrees, for example, the phase margin can be set to 45 degrees.

[0101] In some embodiments, the outer loop controller of the DC bus 31 voltage is a proportional-integral controller 10 .

[0102] Specifically, the transfer function corresponding to the outer loop controller can be set as , voltage loop bandwidth The speed can be 700rad / s, and the phase margin can be set to 45 degrees. .

[0103] The open loop Bode diagram of the DC bus voltage can be referred to Figure 6 The horizontal axis can be set to the frequency value of the input signal of the outer loop controller, in rad / s. The curve of the DC bus 31 voltage after compensation can refer to curve L1, and the curve of the DC bus 31 voltage without compensation can refer to curve L2.

[0104] For curve L1, =700rad / s, the phase angle of the system open-loop frequency response is -135 degrees, and the gain is 0dB, which meets the voltage loop bandwidth Take 700rad / s and the phase margin is 45 degrees. For curve L2, =700rad / s, the phase angle of the system open-loop frequency response is -180 degrees, and the gain is 0dB, which does not meet the voltage loop bandwidth Take 700rad / s and the phase margin is 45 degrees.

[0105] In this way, it can be determined that after the disturbance is compensated, the voltage of the DC bus 31 can be output according to the set transfer function. The disturbance caused by the power loss and the output power is compensated by the disturbance state observer, which can reduce or avoid the influence of various disturbances in the DC bus 31 voltage model on the DC bus 31 voltage, so that the voltage of the DC bus 31 is controlled within a reasonable range, thereby improving the reliability of the converter.

[0106] In some embodiments, the control method may be used for a grid-following converter.

[0107] In certain embodiments, the energy storage converter 100 may include a grid-connected converter.

[0108] Specifically, the grid-following converter is a current source device based on voltage orientation, and its working principle is mainly to control its output by following the voltage and phase of the grid. This type of converter cannot actively adjust its own state, but can only adjust its output current according to the voltage and phase information of the grid to achieve synchronous operation with the grid.

[0109] Grid-following converters are highly dependent on the voltage and phase information of the grid, and are synchronized with the grid through synchronization mechanisms such as phase-locked loops. Grid-following converters are usually unable to actively respond to disturbances in the grid, and may overreact or disconnect from the grid.

[0110] The control method of the implementation mode of the present application can compensate for the internal and external disturbances of the voltage model of the DC bus by improving the control strategy of the grid-following converter, so as to control the voltage of the DC bus of the grid-following converter to be constant, thereby improving the ability and stability of the grid-following converter to cope with grid disturbances.

[0111] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0112] In addition, the term "connection" should be understood in a broad sense, for example, it can include fixed connection, detachable connection, or integral connection; it can include direct connection, indirect connection through an intermediate medium, and internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0113] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0114] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0115] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for controlling a converter, characterized in that: The method comprises: Obtaining a voltage model of the DC bus of the converter, wherein the voltage model is determined according to the active power connected to the converter, the power loss of the DC bus, the output power of the DC bus, and the capacitance value of the DC bus; Determining a nominal model of the voltage model according to the voltage model and a nominal capacitance value of the DC bus; Constructing a disturbance state observer according to the nominal model and the model of the low-pass filter; The internal disturbance of the voltage model caused by the deviation between the actual capacitance value of the DC bus and the nominal capacitance value is compensated according to the disturbance state observer. Within the expected bandwidth of the low-pass filter, the disturbance state observer is configured to compensate for the external disturbance and the internal disturbance so that the voltage model is consistent with the nominal model.

2. The control method according to claim 1, characterized in that: Compensating the disturbance of the voltage model according to a disturbance state observer includes: The external disturbance of the voltage model caused by the loss power and the internal disturbance of the voltage model caused by the output power are compensated according to the disturbance state observer.

3. The control method according to claim 1, characterized in that: The disturbance state observer is configured to compensate for the external disturbance outside a desired bandwidth of the low-pass filter and within a control bandwidth of the low-pass filter.

4. The control method according to claim 3, characterized in that: The converter includes a voltage controller for the DC bus, and the expected bandwidth is determined according to a sampling frequency of the voltage controller.

5. The control method according to claim 1, characterized in that: The method comprises: The active power and the output power are adjusted according to the voltage model to make the voltage value of the DC bus constant.

6. The control method according to claim 1, characterized in that: The method comprises: An outer loop controller of the DC bus voltage is constructed, wherein the outer loop controller is a proportional-integral controller.

7. The control method according to claim 1, characterized in that: The control method is used for a grid-following converter.

8. A controller, characterized in that: The controller includes a memory and a processor, the memory is configured to store a computer program, and the processor implements the control method according to any one of claims 1 to 7 when executing the computer program.

9. A disturbance compensation device, characterized in that: The device comprises: An acquisition module is configured to acquire a voltage model of a DC bus of a converter, wherein the voltage model is determined according to the active power connected to the converter, the power loss of the DC bus, the output power of the DC bus, and the capacitance value of the DC bus; A compensation module is configured to: determine a nominal model of the voltage model according to the voltage model and a nominal capacitance value of the DC bus; Constructing a disturbance state observer according to the nominal model and the model of the low-pass filter; The internal disturbance of the voltage model caused by the deviation between the actual capacitance value of the DC bus and the nominal capacitance value is compensated according to the disturbance state observer. Within the expected bandwidth of the low-pass filter, the disturbance state observer is configured to compensate for the external disturbance and the internal disturbance so that the voltage model is consistent with the nominal model.

10. An energy storage converter, characterized in that: The energy storage converter includes the controller according to claim 8 or the disturbance compensation device according to claim 9.

11. The energy storage converter according to claim 10, characterized in that: The energy storage converter includes a grid-connected converter.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by one or more processors, the control method according to any one of claims 1 to 7 is implemented.

13. A computer device, characterized in that: The computer device includes a memory and a processor, the memory is configured to store a computer program, and the processor implements the control method according to any one of claims 1 to 7 when executing the computer program.

Images