Voltage control method of direct current bus, electronic equipment and computer storage medium

Abstract

The invention discloses a voltage control method of a direct current bus, electronic equipment and a computer storage medium. The voltage control method for the direct current bus comprises the steps of obtaining a first voltage fluctuation value of the direct current bus, and judging whether a load is changed or not based on the first voltage fluctuation value; if the load changes, obtaining a feed-forward current value based on the first voltage fluctuation value; the inverter circuit is controlled and adjusted based on the feed-forward current value; and obtaining a second voltage fluctuation value of the adjusted DC bus, and adjusting the feed-forward current value based on the first voltage fluctuation value and the second voltage fluctuation value. Through the mode, the voltage control method of the direct current bus can perform dynamic current feedforward on the premise of not increasing load current sampling, so that the dynamic fluctuation of the voltage of the direct current bus is effectively inhibited.

Description

Technical Field

[0001] This application relates to the technical field of three-level rectifiers, and particularly to a method for controlling the voltage of a DC bus, an electronic device, and a computer storage medium. Background Art

[0002] With the progress of technology and the improvement of living standards, people's requirements for power quality are also constantly increasing. Multilevel inverters are increasingly used in industrial and social life fields to provide higher-quality electric energy. Taking the active neutral-point-clamped (ANPC) circuit as an example, in the ANPC circuit, its bus voltage will fluctuate accordingly when the load changes suddenly. When the load is suddenly increased, the bus voltage will drop; when the load is suddenly decreased, the bus voltage will rise, and the greater the load change, the greater the dynamic fluctuation of the bus voltage. Therefore, when the load suddenly increases from 0 kW to the full power Pmax, the bus voltage may be undervoltage; similarly, when the load suddenly decreases from the full power Pmax to 0 kW, the bus voltage will be overvoltage.

[0003] To quickly and effectively suppress the dynamic voltage fluctuation in the ANPC circuit, one existing method is to change the gain in the bus voltage loop, that is, dynamically adjust the voltage loop parameters according to the magnitude of the voltage error to achieve rapid adjustment of voltage stability. The disadvantage of this method is that there are many voltage loop parameters, which are not very stable during the switching process, and are prone to mis-triggering, and it is difficult to debug the parameters. Another existing method is to add a load current sampling. In this way, when the load changes suddenly, the command value that should be given to the current loop can be quickly calculated through the load current sampling, that is, adding a load current power feedforward to the current loop. This method is effective and direct, but the disadvantage is that it is necessary to increase the current sampling, which increases the cost. Summary of the Invention

[0004] This application proposes a method for controlling the voltage of a DC bus, an electronic device, and a computer storage medium, aiming to solve the above problems.

[0005] To solve the above technical problems, a technical solution adopted by this application is: to provide a method for controlling the voltage of a DC bus, the method for controlling the voltage of the DC bus includes: obtaining a first voltage fluctuation value of the DC bus, and judging whether the load changes based on the first voltage fluctuation value; if the load changes, obtaining a feedforward current value based on the first voltage fluctuation value; controlling and adjusting the inverter circuit based on the feedforward current value; obtaining a second voltage fluctuation value of the adjusted DC bus, and adjusting the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value.

[0006] Among them, the steps of obtaining the first voltage fluctuation value of the DC bus and determining whether the load has changed based on the first voltage fluctuation value include: obtaining the reference voltage and the sampled voltage of the DC bus; calculating the difference between the reference voltage and the sampled voltage to obtain the first voltage fluctuation value; determining whether the absolute value of the first voltage fluctuation value is greater than a preset voltage fluctuation threshold; and in response to the absolute value of the first voltage fluctuation value being greater than the preset voltage fluctuation threshold, determining that the load has changed.

[0007] Among them, the steps of obtaining the feedforward current value based on the first voltage fluctuation value include: obtaining a preset proportional adjustment coefficient, a bus capacitance value, and a sampling period; calculating the product of the preset proportional adjustment coefficient, the bus capacitance value, and the first voltage fluctuation value; and calculating the quotient of the product and the sampling period to obtain the feedforward current value.

[0008] Among them, after the step of obtaining the second voltage fluctuation value of the adjusted DC bus and before the step of adjusting the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value, the control method includes: determining whether the voltage of the adjusted DC bus is stable; and in response to the voltage being unstable, performing the step of adjusting the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value.

[0009] Among them, the steps of determining whether the voltage of the adjusted DC bus is stable include: determining whether the absolute value of the second voltage fluctuation value is less than or equal to the preset voltage fluctuation threshold within a preset time; and if the absolute value of the second voltage fluctuation value is less than or equal to the preset voltage fluctuation threshold within the preset time, determining that the voltage of the DC bus has become stable.

[0010] Among them, the steps of adjusting the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value include: obtaining the first fluctuation direction before the control adjustment of the inverter circuit based on the first voltage fluctuation value; obtaining the second fluctuation direction after the control adjustment of the inverter circuit based on the second voltage fluctuation value; and adjusting the feedforward current value based on the first fluctuation direction, the second fluctuation direction, the first voltage fluctuation value, and the second voltage fluctuation value.

[0011] Among them, the steps of obtaining the first fluctuation direction before the control adjustment of the inverter circuit based on the first voltage fluctuation value include: determining whether the first voltage fluctuation value is greater than zero; in response to the first voltage fluctuation value being greater than zero, the first fluctuation direction is the undervoltage direction; in response to the first voltage fluctuation value being less than zero, the first fluctuation direction is the overvoltage direction; the steps of obtaining the second fluctuation direction after the control adjustment of the inverter circuit based on the second voltage fluctuation value include: determining whether the second voltage fluctuation value is greater than zero; in response to the second voltage fluctuation value being greater than zero, the second fluctuation direction is the undervoltage direction; in response to the second voltage fluctuation value being less than zero, the second fluctuation direction is the overvoltage direction.

[0012] Among them, the step of adjusting the feedforward current value based on the first fluctuation direction, the second fluctuation direction, the first voltage fluctuation value, and the second voltage fluctuation value includes: in response to the first fluctuation direction and the second fluctuation direction being the undervoltage direction, and the second voltage fluctuation value being greater than the first voltage fluctuation value, increasing the preset proportional adjustment coefficient to adjust the feedforward current value; in response to the first fluctuation direction and the second fluctuation direction being the overvoltage direction, and the second voltage fluctuation value being less than the first voltage fluctuation value, increasing the preset proportional adjustment coefficient to adjust the feedforward current value; in response to the first fluctuation direction and the second fluctuation direction being different, decreasing the preset proportional adjustment coefficient to adjust the feedforward current value.

[0013] To solve the above technical problems, another technical solution adopted by this application is: to provide an electronic device, which includes a processor and a memory connected to the processor. Among them, program data is stored in the memory, and the processor executes the program data stored in the memory to execute the voltage control method of the DC bus described in any one of the above.

[0014] To solve the above technical problems, another technical solution adopted by this application is: to provide a computer-readable storage medium, which stores program instructions internally, and the program instructions are executed by the processor to implement the voltage control method of the DC bus described in any one of the above.

[0015] The beneficial effect of this application is: Different from the prior art, the voltage control method of the DC bus in this application first obtains the first voltage fluctuation value of the DC bus, and judges whether the load has changed based on the first voltage fluctuation value. If the load has changed, the feedforward current value is obtained based on the first voltage fluctuation value, and the inverter circuit is controlled and adjusted based on the feedforward current value; after controlling and adjusting the inverter circuit, the second voltage fluctuation value of the adjusted DC bus is obtained, and the feedforward current value is adjusted based on the first voltage fluctuation value and the second voltage fluctuation value. In the above way, the voltage control method of the DC bus in this application can perform dynamic current feedforward without adding load current sampling, thereby effectively suppressing the dynamic fluctuation of the DC bus voltage. Description of the Drawings

[0016] The drawings here are incorporated into the specification and constitute a part of this specification. These drawings show embodiments that conform to this application and are used together with the specification to illustrate the technical solutions of this application.

[0017] Figure 1 It is a schematic circuit structure diagram of a three-phase ANPC;

[0018] Figure 2 It is a schematic flowchart of the first embodiment of the voltage control method of the DC bus in this application;

[0019] Figure 3 It is a control block diagram of an embodiment of the three-phase ANPC circuit of the present application;

[0020] Figure 4 It is Figure 2 a schematic flow chart of an embodiment of step S101 in

[0021] Figure 5 It is Figure 2 a schematic flow chart of an embodiment of step S102 in

[0022] Figure 6 It is Figure 2 a schematic flow chart of an embodiment of step S104 in

[0023] Figure 7 It is Figure 6 a schematic flow chart of an embodiment of step S401 in

[0024] Figure 8 It is Figure 6 a schematic flow chart of an embodiment of step S402 in

[0025] Figure 9 It is Figure 6 a schematic flow chart of an embodiment of step S403 in

[0026] Figure 10 It is a schematic flow chart of the second embodiment of the voltage control method of the DC bus of the present application;

[0027] Figure 11 It is Figure 10 a schematic flow chart of an embodiment of step S805 in

[0028] Figure 12 It is a schematic diagram of the effect of an embodiment of the dynamic control of the bus voltage of the present application;

[0029] Figure 13 It is a schematic structural diagram of an embodiment of the electronic device of the present application;

[0030] Figure 14 It is a schematic structural diagram of an embodiment of the computer storage medium of the present application. Specific Embodiments

[0031] Next, embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, so they are only examples and cannot be used to limit the protection scope of the present application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are for the purpose of describing specific embodiments only and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above description of the drawings are intended to cover non-exclusive inclusion.

[0033] In the description of the embodiments of this application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "a plurality" is more than two unless otherwise specifically defined.

[0034] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0035] With the progress of technology and the improvement of living standards, people's requirements for power quality are also constantly increasing. Multilevel inverters are increasingly used in industrial and social life and other fields to provide higher-quality electric energy. Taking the active neutral-point-clamped (ANPC) circuit as an example, please refer to Figure 1 , Figure 1 which is a schematic circuit structure diagram of a three-phase ANPC. As Figure 1 shown, the three-phase ANPC circuit 100 includes a DC input module 10, an inverter module 20, and an AC filter output module 30. Among them, the inverter module 20 includes three-phase bridge arms, and each phase bridge arm includes six switching devices, namely the first switching device S1, the second switching device S2, the third switching device S3, the fourth switching device S4, the fifth switching device Sp, and the sixth switching device Sn. When the load connected to the AC filter output module 30 changes suddenly, the voltage of the DC bus at its DC input end will fluctuate accordingly. When suddenly loading, the bus voltage will drop; when suddenly unloading, the bus voltage will rise, and the greater the load change, the greater the dynamic fluctuation of the bus voltage. Therefore, when the load suddenly changes from 0 kW to full power Pmax, the bus voltage may be undervoltage; similarly, when the load suddenly changes from full power Pmax to 0 kW, the bus voltage will be overvoltage.

[0036] To quickly and effectively suppress the dynamic voltage fluctuations in the ANPC circuit, one existing approach is to vary the gain in the bus voltage loop, that is, to dynamically adjust the voltage loop parameters according to the magnitude of the voltage error to achieve rapid adjustment of voltage stability. The disadvantage of this approach is that there are many voltage loop parameters, which are not very stable during the switching process, and are prone to mis-triggering, and the parameter debugging is difficult. Another existing approach is to add a load current sampling. In this way, when the load changes suddenly, the instruction magnitude that should be given to the current loop can be quickly calculated through the load current sampling, that is, adding a load current power feedforward to the current loop. This approach is effective and direct, but the disadvantage is that it is necessary to add current sampling, increasing the cost.

[0037] To solve the above problems, this application first proposes a voltage control method for the DC bus. Please refer to Figure 2 , Figure 2 which is a schematic flow chart of the first embodiment of the voltage control method for the DC bus in this application. As Figure 2 shown, the voltage control method for the DC bus in this embodiment specifically includes steps S101 to S104:

[0038] Step S101: Obtain the first voltage fluctuation value of the DC bus, and determine whether the load has changed based on the first voltage fluctuation value.

[0039] In this embodiment, taking the ANPC circuit in Figure 1 as an example, in the ANPC circuit, the voltage of its DC bus will fluctuate accordingly when the load changes suddenly. When suddenly loaded, the bus voltage will drop, and when suddenly unloaded, the bus voltage will rise, and the greater the load change, the greater the dynamic fluctuation of the bus voltage. Therefore, when the load suddenly changes from 0 kW to full power Pmax, the bus voltage may be undervoltage; similarly, when the load suddenly changes from full power Pmax to 0 kW, the bus voltage will be overvoltage. Therefore, in order to effectively suppress the fluctuations of the DC bus voltage in the ANPC circuit and maintain the voltage balance of the DC bus, a current feedforward module is added to the control system of the three-phase ANCP circuit in this embodiment. Therefore, without adding load current sampling, by predicting the magnitude of the load current and performing dynamic current feedforward, the dynamic fluctuations of the bus voltage can be effectively suppressed without increasing the sampling cost.

[0040] Please refer to Figure 3 , Figure 3 which is a control block diagram of an embodiment of the three-phase ANPC circuit in this application. As Figure 3 shown, the control system 200 of the three-phase ANPC circuit in this embodiment includes a voltage loop module 210, a current loop module 220, a modulation module 230, and a current feedforward module 240. The input of the current feedforward module 240 is the feedforward current value i obtained by calculating the voltage control method for the DC bus in this embodiment ffd, the feedforward current value i ffd After being added to the output of the voltage loop module 210, it serves as the given input of the d-axis current loop in the current loop module 220, and through the control and adjustment of the current loop module 220 and the modulation module 230, the voltage balance of the DC bus of the three-phase ANPC circuit is maintained.

[0041] Based on the above analysis, it can be seen that when the load changes, the voltage of the DC bus of the three-phase ANPC circuit will fluctuate. At this time, in order to maintain the voltage balance of the DC bus, the current feedforward module 240 needs to be adjusted.

[0042] Therefore, in order to maintain the voltage balance of the DC bus, first, it is necessary to obtain the first voltage fluctuation value of the DC bus in the three-phase ANPC circuit, and judge whether the load has changed based on the first voltage fluctuation value.

[0043] Among them, in this embodiment, the voltage of the DC bus can be sampled and the difference from the reference voltage can be calculated, so as to obtain the absolute value of the first voltage fluctuation value of the DC bus at the current moment, and compare it with the preset voltage threshold to judge whether the load has changed. If the absolute value of the first voltage fluctuation value is greater than the preset voltage threshold, it is determined that the load has changed. If the absolute value of the first voltage fluctuation value is less than or equal to the preset voltage threshold, it is determined that the load has not changed, and there is no need to adjust the feedforward current value i ffd for adjustment.

[0044] If the load changes, go to step S102.

[0045] Step S102: Obtain the feedforward current value based on the first voltage fluctuation value.

[0046] As described above, if the load changes, it is necessary to obtain the feedforward current value i based on the first voltage fluctuation value ffd . Among them, the method of calculating the feedforward current value i based on the first voltage fluctuation value ffd is as shown below and will not be described in detail here.

[0047] Step S103: Control and adjust the inverter circuit based on the feedforward current value.

[0048] Based on the above, after obtaining the feedforward current value i based on the first voltage fluctuation value ffd , the feedforward current value i ffd is input to the current feedforward module 240, and the three-phase ANPC circuit (inverter circuit) is controlled and adjusted based on the three-phase ANPC circuit control system 200.

[0049] Step S104: Obtain the second voltage fluctuation value of the adjusted DC bus, and adjust the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value.

[0050] When controlling and adjusting a three-phase ANPC circuit (inverter circuit) based on a feed-forward current value, it is still necessary to obtain a second voltage fluctuation value of the adjusted DC bus. Among them, the method for obtaining the second voltage fluctuation value is the same as the method for obtaining the first voltage fluctuation value. The purpose of obtaining the second voltage fluctuation value at this time is to determine the feed-forward current value i calculated before the adjustment ffd Whether it can suppress the voltage fluctuation of the DC bus. If it can suppress the voltage fluctuation of the DC bus, there is no need to adjust the feed-forward current value i ffd For adjustment, if it cannot suppress the voltage fluctuation of the DC bus or over-compensation occurs, then the feed-forward current value i ffd For adjustment, specifically, the adjustment method is as described below and will not be described in detail here.

[0051] In addition, in other embodiments, the voltage control method of the DC bus in this embodiment can also be applied to the bus voltage control of other topologies, such as the bus voltage control of a three-phase T-type three-level topology or a three-phase H-bridge topology, which is not limited here.

[0052] Different from the prior art, the voltage control method of the DC bus in this application first obtains a first voltage fluctuation value of the DC bus, and judges whether the load has changed based on the first voltage fluctuation value. If the load has changed, a feed-forward current value is obtained based on the first voltage fluctuation value, and the inverter circuit is controlled and adjusted based on the feed-forward current value; after controlling and adjusting the inverter circuit, a second voltage fluctuation value of the adjusted DC bus is obtained, and the feed-forward current value is adjusted based on the first voltage fluctuation value and the second voltage fluctuation value. In the above manner, the voltage control method of the DC bus in this application can perform dynamic current feed-forward without increasing the load current sampling, thereby effectively suppressing the dynamic voltage fluctuation of the DC bus.

[0053] Optionally, the method for obtaining the first voltage fluctuation value of the DC bus and judging whether the load has changed based on the first voltage fluctuation value is as Figure 4 As shown, please refer to Figure 4 , Figure 4 Is Figure 2 A schematic flowchart of an embodiment of step S101 in. This embodiment can implement step S101 through the method as Figure 4 As shown, the specific implementation steps include steps S201 to S204:

[0054] Step S201: Obtain the reference voltage and the sampled voltage of the DC bus.

[0055] As described above, when determining whether the load of the inverter circuit has changed, it is necessary to obtain the first voltage fluctuation value of the DC bus. Therefore, the reference voltage of the DC bus is obtained, and the voltage of the DC bus at the current moment is sampled to obtain the sampled voltage.

[0056] Step S202: Calculate the difference between the reference voltage and the sampled voltage to obtain the first voltage fluctuation value.

[0057] By calculating the difference between the reference voltage and the sampled voltage, the first voltage fluctuation value can be obtained.

[0058] Step S203: Determine whether the absolute value of the first voltage fluctuation value is greater than a preset voltage fluctuation threshold.

[0059] At this time, the absolute value of the first voltage fluctuation value is compared with the preset voltage fluctuation threshold. The preset voltage fluctuation threshold can be set based on the actual situation of the circuit and is not limited here.

[0060] Step S204: In response to the absolute value of the first voltage fluctuation value being greater than the preset voltage fluctuation threshold, it is determined that the load has changed.

[0061] If the absolute value of the first voltage fluctuation value is greater than the preset voltage threshold, it is determined that the load has changed. If the absolute value of the first voltage fluctuation value is less than or equal to the preset voltage threshold, it is determined that the load has not changed.

[0062] Optionally, the method for obtaining the feedforward current value based on the first voltage fluctuation value is as Figure 5 shown. Please refer to Figure 5 , Figure 5 which Figure 2 is a schematic flowchart of an embodiment of step S102 in Figure 5 . This embodiment can implement step S102 through the method shown in

[0063] Step S301: Obtain a preset proportional adjustment coefficient, a bus capacitance value, and a sampling period.

[0064] After obtaining the first voltage fluctuation value, the feedforward current value can be calculated based on the formula of the first voltage fluctuation value and the feedforward current value. The calculation formula of the feedforward current value is as follows:

[0065]

[0066] where, i ffd is the feedforward current value, Kp is the preset proportional adjustment coefficient, C dc is the bus capacitance value, errVoltPre is the first voltage fluctuation value, and ΔT is the sampling period.

[0067] Therefore, based on the above formula, after obtaining the first voltage fluctuation value, it is first necessary to obtain the preset proportional adjustment coefficient Kp, the bus capacitance value C dc and the sampling period ΔT.

[0068] Step S302: Calculate the product of the preset proportional adjustment coefficient, the bus capacitance value, and the first voltage fluctuation value.

[0069] At this time, calculate the product of the preset proportional adjustment coefficient Kp, the bus capacitance value C dc and the first voltage fluctuation value Kp*C dc *errVoltPre.

[0070] Step S303: Calculate the quotient of the product and the sampling period to obtain the feedforward current value.

[0071] Finally, calculate the quotient of the product Kp*C dc *errVoltPre and the sampling period ΔT, and the feedforward current value i ffd .

[0072] Optionally, the method for adjusting the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value is as Figure 6 shown. Please refer to Figure 6 , Figure 6 which is Figure 2 a schematic flowchart of an embodiment of step S104 in Figure 6 . This embodiment can implement step S104 through the method shown in

[0073] Step S401: Obtain the first fluctuation direction before the inverter circuit performs control adjustment based on the first voltage fluctuation value.

[0074] After obtaining the first voltage fluctuation value before the inverter circuit performs control adjustment, the first fluctuation direction of the DC bus voltage before the inverter circuit performs control adjustment can be obtained based on the positive or negative of the first voltage fluctuation value.

[0075] Step S402: Obtain the second fluctuation direction after the inverter circuit performs control adjustment based on the second voltage fluctuation value.

[0076] After obtaining the second voltage fluctuation value after the inverter circuit performs control adjustment, the second fluctuation direction of the DC bus voltage after the inverter circuit performs control adjustment can be obtained based on the positive or negative of the second voltage fluctuation value.

[0077] Step S403: Adjust the feedforward current value based on the first fluctuation direction, the second fluctuation direction, the first voltage fluctuation value, and the second voltage fluctuation value.

[0078] Based on the first fluctuation direction, the second fluctuation direction, the first voltage fluctuation value, and the second voltage fluctuation value, it is possible to determine the current feedforward value \(i\) obtained before the control adjustment. ffd Whether to continue the adjustment. If the current feedforward value \(i\) ffd cannot suppress the DC bus voltage fluctuation or overcompensate, then the current feedforward value \(i\) ffd needs to be further adjusted. The specific adjustment method is described below.

[0079] Optionally, the method for obtaining the first fluctuation direction of the inverter circuit before control adjustment based on the first voltage fluctuation value is as Figure 7 shown. Please refer to Figure 7 , Figure 7 which Figure 6 is a schematic flowchart of an embodiment of step S401 in Figure 7 . This embodiment can implement step S401 through the method as

[0080] shown, and the specific implementation steps include steps S501 to S503:

[0081] Step S501: Determine whether the first voltage fluctuation value is greater than zero.

[0082] The current feedforward module determines whether the first fluctuation value is greater than zero.

[0083] Step S502: In response to the first voltage fluctuation value being greater than zero, the first fluctuation direction is the undervoltage direction.

[0084] If the first voltage fluctuation value is greater than zero, it indicates that this voltage fluctuation is caused by loading, then the first fluctuation direction can be determined as the undervoltage direction.

[0085] Step S503: In response to the first voltage fluctuation value being less than zero, the first fluctuation direction is the overvoltage direction.

[0086] Optionally, the method for obtaining the second fluctuation direction of the inverter circuit after control adjustment based on the second voltage fluctuation value is as Figure 8 shown. Please refer to Figure 8 , Figure 8 which Figure 6 is a schematic flowchart of an embodiment of step S402 in Figure 8 . This embodiment can implement step S402 through the method as

[0087] Step S601: Determine whether the second voltage fluctuation value is greater than zero.

[0088] The current feedforward module determines whether the second fluctuation value is greater than zero.

[0089] Step S602: In response to the second voltage fluctuation value being greater than zero, the second fluctuation direction is the undervoltage direction.

[0090] If the second voltage fluctuation value is greater than zero, it indicates that after adjusting and controlling the inverter circuit with the current feedforward value i ffd at this time, the voltage of the DC bus is less than the reference voltage, then it can be determined that the second fluctuation direction is the undervoltage direction.

[0091] Step S603: In response to the second voltage fluctuation value being less than zero, the second fluctuation direction is the overvoltage direction.

[0092] If the second voltage fluctuation value is less than zero, it indicates that after adjusting and controlling the inverter circuit with the current feedforward value i ffd at this time, the voltage of the DC bus is greater than the reference voltage, then it can be determined that the second fluctuation direction is the overvoltage direction.

[0093] Optionally, the method for adjusting the feedforward current value based on the first fluctuation direction, the second fluctuation direction, the first voltage fluctuation value, and the second voltage fluctuation value is as Figure 9 shown, please refer to Figure 9 , Figure 9 is Figure 6 a schematic flowchart of an embodiment of step S403 in Figure 9 This embodiment can implement step S403 through the method shown in

[0094] Step S701: In response to the first fluctuation direction and the second fluctuation direction being the undervoltage direction, and the second voltage fluctuation value being greater than the first voltage fluctuation value, increase the preset proportional adjustment coefficient to adjust the feedforward current value.

[0095] If the first fluctuation direction and the second fluctuation direction are both the undervoltage direction, as described above, the first fluctuation direction being the undervoltage direction indicates that this voltage fluctuation is caused by loading. If after adjusting and controlling the inverter circuit with the current feedforward value i ffd at this time, the second fluctuation direction is still the undervoltage direction, then it is necessary to further determine whether the second voltage fluctuation value is greater than the first voltage fluctuation value; if the second voltage fluctuation value is greater than the first voltage fluctuation value, it indicates that the value of the current feedforward value i ffd is too small, and it is necessary to increase the current feedforward value i ffd in the formula of the preset proportional adjustment coefficient Kp to increase the current feedforward value i ffd; If the current second fluctuation direction is the undervoltage direction, but the second voltage fluctuation value is less than or equal to the first voltage fluctuation value, it indicates that the voltage fluctuation of the DC bus has been suppressed and is approaching the reference voltage, indicating that the current value of the current feedforward i ffd has a suitable value and there is no need to update the value of the current feedforward i ffd .

[0096] Step S702: In response to the first fluctuation direction and the second fluctuation direction being the overvoltage direction, and the second voltage fluctuation value being less than the first voltage fluctuation value, increase the preset proportional adjustment coefficient to adjust the feedforward current value.

[0097] If both the first fluctuation direction and the second fluctuation direction are the overvoltage direction, as described above, if the first fluctuation direction is the undervoltage direction, it indicates that this voltage fluctuation is caused by load shedding. If after adjusting and controlling the inverter circuit with the current value of the current feedforward i ffd , and the second fluctuation direction is still the overvoltage direction at this time, it is necessary to further determine whether the second voltage fluctuation value is less than the first voltage fluctuation value; if the second voltage fluctuation value is less than the first voltage fluctuation value, it indicates that the current value of the current feedforward i ffd is too small and it is necessary to increase the value of the current feedforward i ffd in the formula of the preset proportional adjustment coefficient Kp to increase the current value of the current feedforward i ffd ; If the current second fluctuation direction is the undervoltage direction, but the second voltage fluctuation value is greater than or equal to the first voltage fluctuation value, it indicates that the voltage fluctuation of the DC bus has been suppressed and is approaching the reference voltage, indicating that the current value of the current feedforward i ffd has a suitable value and there is no need to update the value of the current feedforward i ffd .

[0098] Step S703: In response to the first fluctuation direction and the second fluctuation direction being different, decrease the preset proportional adjustment coefficient to adjust the feedforward current value.

[0099] In this embodiment, there are two cases where the first fluctuation direction and the second fluctuation direction are different. The first case is that the first fluctuation direction is the undervoltage direction and the second fluctuation direction is the overvoltage direction; the second case is that the first fluctuation direction is the overvoltage direction and the second fluctuation direction is the undervoltage direction.

[0100] In the first case, if the first fluctuation direction is the undervoltage direction, as described above, if the first fluctuation direction is the undervoltage direction, it indicates that this voltage fluctuation is caused by load addition. If after adjusting and controlling the inverter circuit with the current value of the current feedforward i ffd , and the second fluctuation direction is the overvoltage direction at this time, it indicates that the current value of the current feedforward i ffd is too large, resulting in the reverse of the voltage fluctuation of the DC bus. At this time, it is necessary to decrease the value of the current feedforward iffd The preset proportional adjustment coefficient Kp in the formula is used to reduce the current feedforward value i at present ffd .

[0101] Similarly, in the second case, if the first fluctuation direction is the overvoltage direction, as described above, if the first fluctuation direction is the overvoltage direction, it indicates that this voltage fluctuation is caused by load shedding. If the current feedforward value i at present ffd After adjusting and controlling the inverter circuit, if the second fluctuation direction is the undervoltage direction at this time, it indicates that the current feedforward value i at present ffd is too large, resulting in the reverse of the voltage fluctuation of the DC bus. At this time, it is also necessary to reduce the current feedforward value i ffd The preset proportional adjustment coefficient Kp in the formula is used to reduce the current feedforward value i at present ffd .

[0102] Based on the above embodiments, through the above method, the voltage control method of the DC bus of the present application can suppress the voltage fluctuation during load addition and shedding within the preset voltage fluctuation threshold range without sampling the load current.

[0103] Optionally, based on the above embodiments, the present application further proposes a voltage control method for a DC bus. Please refer to Figure 10 , Figure 10 which is a schematic flowchart of the second embodiment of the voltage control method for the DC bus of the present application. As Figure 10 shown, the voltage control method for the DC bus in this embodiment specifically includes steps S801 to S806:

[0104] Step S801: Obtain the first voltage fluctuation value of the DC bus, and determine whether the load has changed based on the first voltage fluctuation value.

[0105] If the load has changed, go to step S802.

[0106] Step S801 is the same as step S101 and will not be elaborated.

[0107] Step S802: Obtain the feedforward current value based on the first voltage fluctuation value.

[0108] Step S802 is the same as step S102 and will not be elaborated.

[0109] Step S803: Control and adjust the inverter circuit based on the feedforward current value.

[0110] Step S803 is the same as step S103 and will not be elaborated.

[0111] Step S804: Obtain the second voltage fluctuation value of the adjusted DC bus.

[0112] The step of obtaining the second voltage fluctuation value of the adjusted DC bus in step S804 is the same as that in step S104, and will not be elaborated here.

[0113] Step S805: Determine whether the voltage of the adjusted DC bus is stable.

[0114] After obtaining the circuit feedforward value to adjust and control the inverter circuit, the voltage of the current DC bus can be further obtained and calculated with the reference voltage to obtain the second voltage fluctuation value. At this time, by comparing the second voltage fluctuation value with the preset voltage fluctuation threshold, it can be determined whether the voltage of the adjusted DC bus is stable. If the second voltage fluctuation value is less than the preset voltage fluctuation threshold within the preset time, the voltage is stable; if the second voltage fluctuation value is greater than or equal to the preset voltage fluctuation threshold, the voltage is unstable.

[0115] If the voltage is unstable, go to step S806.

[0116] Step S806: Adjust the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value.

[0117] Step S806 is the same as the step of adjusting the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value in step S104, and will not be elaborated here.

[0118] Optionally, based on Figure 10 of the embodiment, the method for determining whether the voltage of the adjusted DC bus is stable is as Figure 11 shown. Please refer to Figure 11 , Figure 11 is Figure 10 a schematic flowchart of an embodiment of step S805 in Figure 11 . This embodiment can implement step S805 through the method shown in

[0119] Step S901: Determine whether the absolute value of the second voltage fluctuation value is less than or equal to the preset voltage fluctuation threshold within the preset time.

[0120] After obtaining the second voltage fluctuation value within the preset time, determine whether the absolute value of the second voltage fluctuation value is less than or equal to the preset voltage fluctuation threshold within the preset time.

[0121] If the absolute value of the second voltage fluctuation value is less than or equal to the preset voltage fluctuation threshold within the preset time, it is determined that the voltage of the DC bus has been stabilized, and there is no need to update the current feedforward value i ffd , if the absolute value of the second voltage fluctuation value is greater than the preset voltage fluctuation threshold, go to step S902.

[0122] Among them, the preset time can be set based on the actual situation. In other embodiments, other thresholds can also be further used for judgment, as long as the threshold is less than the set voltage fluctuation threshold, which is not limited here.

[0123] Step S902: Adjust the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value.

[0124] Step S902 is the same as step S806 and will not be elaborated here.

[0125] Different from the prior art, the voltage control method of the DC bus in this application first obtains the first voltage fluctuation value of the DC bus, and judges whether the load has changed based on the first voltage fluctuation value. If the load has changed, the feedforward current value is obtained based on the first voltage fluctuation value, and the inverter circuit is controlled and adjusted based on the feedforward current value; after controlling and adjusting the inverter circuit, the second voltage fluctuation value of the adjusted DC bus is obtained, and the feedforward current value is adjusted based on the first voltage fluctuation value and the second voltage fluctuation value. In the above manner, the voltage control method of the DC bus in this application can perform dynamic current feedforward without increasing the load current sampling, thereby effectively suppressing the dynamic voltage fluctuation of the DC bus.

[0126] In an application scenario, a flag signal can be set in the current feedforward module. The flag signal is used to record whether a voltage fluctuation has occurred. In the initial state, flag is 0. When the first voltage fluctuation value errVolt is greater than the preset voltage fluctuation threshold A (the size of the preset voltage fluctuation threshold A is set as long as it is greater than the ripple when the voltage is stable), it means that the load has changed. At this time, record the voltage errVoltT1 = errVolt and errVoltPre = errVolt at this moment, and calculate the current feedforward value i of this cycle using the formula in the previous text ffd , and assign the flag value to 1.

[0127] When the flag signal is 1, it means that the voltage dynamic fluctuation control process is in progress at this time. At this time, judge whether the bus voltage has stabilized. If it has stabilized, assign the current feedforward value to the current feedforward, and clear all variables flag, errVoltT1, errVoltPre and the current feedforward value i ffd to zero. The method for judging voltage stability can be judged according to the absolute value of errVolt continuously being less than the threshold, and this threshold is less than A. If the bus voltage has not stabilized, it is necessary to continue to judge whether to adjust and update the current feedforward value i ffdValue. First, determine the first voltage fluctuation direction at the moment of triggering voltage fluctuation. If errVoltT1 > 0, it indicates that this voltage fluctuation is caused by loading. Based on the second voltage fluctuation value errVolt at the current moment, obtain the second voltage fluctuation direction at the current moment. If errVolt < 0 at the current moment, it means that the previous current feedforward value i ffd is too large, resulting in the reverse of voltage fluctuation. Therefore, in this case, reduce the Kp value of the current feedforward value i ffd , and recalculate the current feedforward value i ffd for feedforward; if errVolt > 0 at the current moment, then further determine whether errVolt is greater than errVoltPre. If so, it means that the previous current feedforward value i ffd is too small, and continue to increase the current feedforward value i ffd 's Kp value, and recalculate the current feedforward value i ffd for feedforward, and assign the errVolt at the current moment to the variable errVoltPre; if errVolt > 0 at the current moment, but errVolt < errVoltPre, it means that the voltage fluctuation has been suppressed and is approaching the reference voltage, indicating that the previous current feedforward value i ffd is appropriate and there is no need to update the magnitude of the current feedforward value i ffd . Just assign the errVolt at the current moment to the variable errVoltPre.

[0128] Similarly, if errVoltT1 < 0, it indicates that this voltage fluctuation is caused by unloading. Determine errVolt at the current moment. If errVolt > 0 at the current moment, it means that the previous current feedforward value i ffd is too large, resulting in the reverse of voltage fluctuation. Therefore, in this case, reduce the Kp value of the current feedforward value i ffd , and recalculate the current feedforward value i ffd for feedforward. If errVolt < 0 at the current moment as well, then further determine whether errVolt is less than errVoltPre. If so, it means that the previous current feedforward value i ffd is too small, and continue to increase the current feedforward value i ffd 's Kp value, and recalculate the current feedforward value i ffd for feedforward, and assign the errVolt at the current moment to the variable errVoltPre; if errVolt < 0 at the current moment, but errVolt > errVoltPre, it means that the voltage fluctuation has been suppressed and is approaching the reference voltage, indicating that the previous current feedforward value i ffd is appropriate and there is no need to update the current feedforward value i ffdRegarding the size, simply assign the errVolt at the current moment to the variable errVoltPre.

[0129] Please refer to Figure 12 , Figure 12 which is a schematic diagram of the effect of an embodiment of the bus voltage dynamic control of the present application. As Figure 12 shown, by applying the control method of the DC bus of the present application, the voltage fluctuation during load addition and removal can be suppressed within the preset voltage fluctuation threshold range without sampling the load current.

[0130] Optionally, the present application further proposes an electronic device. Please refer to Figure 13 , Figure 13 which is a schematic structural diagram of an embodiment of the electronic device of the present application. The electronic device 300 includes a processor 301 and a memory 302 connected to the processor 301.

[0131] The processor 301 can also be referred to as a CPU (Central Processing Unit). The processor 301 may be an integrated circuit chip with signal processing capabilities. The processor 301 can also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc.

[0132] The memory 302 is used to store the program data required for the operation of the processor 301.

[0133] The processor 301 is further configured to execute the program data stored in the memory 302 to implement the voltage control method of the DC bus in any of the above.

[0134] Optionally, the present application further proposes a computer storage medium. Please refer to Figure 14 , Figure 14 which is a schematic structural diagram of an embodiment of the computer storage medium of the present application.

[0135] The computer storage medium 400 of the embodiment of the present application stores program instructions 410 internally, and the program instructions 410 are executed to implement the voltage control method of the DC bus in any of the above.

[0136] Among them, the program instructions 410 can form a program file and be stored in the above storage medium in the form of a software product, so that an electronic device (which can be a personal computer, a server, or a network device, etc.) or a processor can execute all or part of the steps of the methods in various embodiments of the present application. The foregoing storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc, or a terminal device such as a computer, a server, a mobile phone, or a tablet.

[0137] The computer storage medium 400 in this embodiment can be, but is not limited to, a USB flash drive, an SD card, a PD optical drive, a mobile hard disk, a high-capacity floppy drive, a flash memory, a multimedia memory card, a server, etc.

[0138] In one embodiment, a computer program product or a computer program is provided. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer storage medium. The processor of the electronic device reads the computer instructions from the computer storage medium, and the processor executes the computer instructions, so that the electronic device executes the steps in the above method embodiments.

[0139] In addition, if the above functions are implemented in the form of software functions and sold or used as an independent product, they can be stored in a storage medium readable by a mobile terminal. That is, the present application also provides a storage device storing program data, and the program data can be executed to implement the methods of the above embodiments. The storage device can be, for example, a USB flash drive, an optical disc, a server, etc. That is to say, the present application can be embodied in the form of a software product, which includes several instructions to enable an intelligent terminal to execute all or part of the steps of the methods in various embodiments.

[0140] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0141] Any process or method description represented in a flowchart or otherwise described herein can be understood to represent an apparatus, segment, or portion of code including one or more executable instructions for implementing a specific logical function or process. The scope of the preferred embodiments of the present application includes additional implementations, where functions may be performed in an order not shown or discussed, including in a substantially simultaneous manner according to the involved functions or in a reverse order, which should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0142] The logic and / or steps represented in a flowchart or otherwise described herein, for example, can be considered a sequenced list of executable instructions for implementing a logical function and can be specifically implemented in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device (which can be a personal computer, server, network device, or other system that can fetch and execute instructions from the instruction execution system, apparatus, or device). For the purposes of this specification, a "computer storage medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection having one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which a program can be printed, as the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other appropriate processing as necessary, and then stored in a computer memory.

[0143] The above are only embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. A voltage control method for a DC bus, characterized in that, Including: Obtain a first voltage fluctuation value of the DC bus, and determine whether the load has changed based on the first voltage fluctuation value; If the load has changed, obtain a feedforward current value based on the first voltage fluctuation value; Control and adjust the inverter circuit based on the feedforward current value; Obtain a second voltage fluctuation value of the adjusted DC bus, and adjust the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value.

2. The voltage control method according to claim 1, wherein The step of obtaining the first voltage fluctuation value of the DC bus and determining whether the load has changed based on the first voltage fluctuation value includes: Obtain a reference voltage and a sampled voltage of the DC bus; Calculate the difference between the reference voltage and the sampled voltage to obtain the first voltage fluctuation value; Judge whether the absolute value of the first voltage fluctuation value is greater than a preset voltage fluctuation threshold; In response to the absolute value of the first voltage fluctuation value being greater than the preset voltage fluctuation threshold, determine that the load has changed.

3. The voltage control method according to claim 1, wherein The step of obtaining a feedforward current value based on the first voltage fluctuation value includes: Obtain a preset proportional adjustment coefficient, a bus capacitance value, and a sampling period; Calculate the product of the preset proportional adjustment coefficient, the bus capacitance value, and the first voltage fluctuation value; Calculate the quotient of the product and the sampling period to obtain the feedforward current value.

4. The voltage control method according to claim 3, wherein After the step of obtaining the second voltage fluctuation value of the adjusted DC bus and before the step of adjusting the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value, the control method includes: Judge whether the voltage of the adjusted DC bus is stable; In response to the voltage being unstable, execute the step of adjusting the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value.

5. The voltage control method according to claim 4, wherein The step of judging whether the voltage of the adjusted DC bus is stable includes: Judge whether the absolute value of the second voltage fluctuation value is less than or equal to the preset voltage fluctuation threshold within a preset time; If the absolute value of the second voltage fluctuation value is less than or equal to the preset voltage fluctuation threshold within the preset time, determine that the voltage of the DC bus has been stable.

6. The voltage control method according to claim 4, wherein The step of adjusting the feedforward current value based on the first voltage fluctuation value and the second voltage fluctuation value includes: Obtain a first fluctuation direction before the control adjustment of the inverter circuit based on the first voltage fluctuation value; Obtain a second fluctuation direction after the control adjustment of the inverter circuit based on the second voltage fluctuation value; Adjust the feedforward current value based on the first fluctuation direction, the second fluctuation direction, the first voltage fluctuation value, and the second voltage fluctuation value.

7. The voltage control method according to claim 6, wherein The step of obtaining the first fluctuation direction before the control adjustment of the inverter circuit based on the first voltage fluctuation value includes: Judge whether the first voltage fluctuation value is greater than zero; In response to the first voltage fluctuation value being greater than zero, the first fluctuation direction is the undervoltage direction; in response to the first voltage fluctuation value being less than zero, the first fluctuation direction is the overvoltage direction; The step of obtaining the second fluctuation direction after control adjustment of the inverter circuit based on the second voltage fluctuation value includes: Determine whether the second voltage fluctuation value is greater than zero; in response to the second voltage fluctuation value being greater than zero, the second fluctuation direction is the undervoltage direction; in response to the second voltage fluctuation value being less than zero, the second fluctuation direction is the overvoltage direction.

8. The voltage control method according to claim 7, wherein The step of adjusting the feedforward current value based on the first fluctuation direction, the second fluctuation direction, the first voltage fluctuation value, and the second voltage fluctuation value includes: In response to the first fluctuation direction and the second fluctuation direction being the undervoltage direction, and the second voltage fluctuation value being greater than the first voltage fluctuation value, increase the preset proportional adjustment coefficient to adjust the feedforward current value; In response to the first fluctuation direction and the second fluctuation direction being the overvoltage direction, and the second voltage fluctuation value being less than the first voltage fluctuation value, increase the preset proportional adjustment coefficient to adjust the feedforward current value; In response to the first fluctuation direction and the second fluctuation direction being different, decrease the preset proportional adjustment coefficient to adjust the feedforward current value.

9. An electronic device, characterized in that, The electronic device includes a processor and a memory connected to the processor. Among them, program data is stored in the memory, and the processor executes the program data stored in the memory to execute the voltage control method of the DC bus described in any one of claims 1-8.

10. A computer storage medium, characterized in that, It internally stores program instructions, and the program instructions are executed to implement the voltage control method of the DC bus described in any one of claims 1-8.

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