Control method and device of power converter, control equipment and power converter

Abstract

The invention provides a control method and device of a power converter, control equipment and the power converter, and belongs to the technical field of power supplies. The control method of the power converter comprises the following steps: acquiring a three-phase modulation wave fundamental wave of the power converter; if the modulation wave fundamental wave of any phase is located in the zero-crossing clamping interval, adding a first zero-sequence component to the modulation wave fundamental waves of the three phases to obtain modulation waves of the three phases; the first zero-sequence component is an opposite number of an intermediate value in the fundamental wave of the three-phase modulation wave; and controlling the power converter based on the three-phase modulation wave. According to the invention, the fundamental wave of the modulation wave in the zero-crossing clamping interval can be clamped to 0, so that when the input current crosses the zero point, the modulation wave also crosses the zero point, and the input current can be prevented from generating distortion at the zero-crossing point to influence the quality of the output current.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply, and in particular to a control method, device, control equipment and power converter of a power converter. Background Art

[0002] The power converter can convert AC power into DC power, and can be controlled by discontinuous pulse width modulation (DPWM). When the power converter is controlled by DPWM, there is a certain phase difference between the modulation wave and the input current. When the input current passes through zero, the modulation wave may have reversed, which can easily cause the input current to be distorted when it passes through zero, thereby affecting the output current quality. Summary of the invention

[0003] The embodiments of the present invention provide a control method, an apparatus, a control device and a power converter for a power converter, so as to solve the problem that the existing control method easily causes the input current to be distorted when crossing the zero point, thereby affecting the quality of the output current.

[0004] In a first aspect, an embodiment of the present invention provides a control method for a power converter, comprising:

[0005] Obtaining the three-phase modulation wave fundamental of the power converter;

[0006] If the modulation wave fundamental wave of any phase is within the zero-crossing clamping interval, the modulation wave fundamental waves of the three phases are all added with the first zero-sequence component to obtain the modulation wave of the three phases; the first zero-sequence component is the opposite number of the middle value of the modulation wave fundamental wave of the three phases;

[0007] The power converter is controlled based on the three-phase modulation wave.

[0008] In a possible implementation, if the modulation wave fundamental wave of any phase is located in the zero-crossing clamping interval, the modulation wave fundamental waves of the three phases are all added with the first zero-sequence component to obtain the modulation waves of the three phases, and the method further includes:

[0009] Obtaining three-phase input current and input current ripple of the power converter;

[0010] Based on the three-phase input current, determine the D-axis component, Q-axis component and peak value of the input current;

[0011] The zero-crossing clamping interval is determined based on the D-axis component, the Q-axis component, the peak value, and the input current ripple.

[0012] In a possible implementation, the zero-crossing clamping interval includes:

[0013]

[0014] Where Iripple is the input current ripple; Iq is the Q-axis component; Id is the D-axis component; I PK is the peak value; k is an integer.

[0015] In a possible implementation, after obtaining the three-phase modulation wave fundamental of the power converter, the method further includes:

[0016] If the fundamental waves of the modulation waves of the three phases are not within the zero-crossing clamping interval, the upper half bus voltage and the lower half bus voltage of the power converter are obtained;

[0017] Compare the absolute value of the upper bus voltage with the absolute value of the lower bus voltage to obtain a comparison result;

[0018] Determine the second zero-sequence component according to the comparison result and the fundamental wave of the modulation wave of the three phases;

[0019] The second zero-sequence component is added to the three-phase modulation wave fundamental waves to obtain the three-phase modulation wave, and the step of controlling the power converter based on the three-phase modulation wave is executed.

[0020] In a possible implementation, determining the second zero-sequence component according to the comparison result and the fundamental wave of the three-phase modulation wave includes:

[0021] If the comparison result is that the absolute value of the upper half bus voltage is greater than the absolute value of the lower half bus voltage, the second zero-sequence component is determined based on the minimum value of the fundamental wave of the three-phase modulation wave;

[0022] If the comparison result is that the absolute value of the upper half bus voltage is smaller than the absolute value of the lower half bus voltage, the second zero-sequence component is determined based on the maximum value of the fundamental wave of the three-phase modulation wave.

[0023] In a possible implementation, the calculation formula of the second zero-sequence component m2 is:

[0024]

[0025] Among them, m min is the minimum value of the three-phase modulation wave fundamental wave; m max is the maximum value of the three-phase modulation wave fundamental wave; U Cp is the upper bus voltage; U Cn is the lower half bus voltage.

[0026] In a possible implementation, the power converter is an AC-DC converter; and the fundamental wave of the modulation wave is a sine wave.

[0027] In a second aspect, an embodiment of the present invention provides a control device for a power converter, comprising:

[0028] An acquisition module, used for acquiring the three-phase modulation wave fundamental wave of the power converter;

[0029] The modulation wave determination module is used for adding the first zero-sequence component to the modulation wave fundamentals of the three phases to obtain the modulation waves of the three phases if the modulation wave fundamental of any phase is within the zero-crossing clamping interval; the first zero-sequence component is the opposite number of the middle value of the modulation wave fundamental of the three phases;

[0030] The control module is used to control the power converter based on the three-phase modulation wave.

[0031] In a third aspect, an embodiment of the present invention provides a control device, comprising a processor and a memory, the memory being used to store a computer program, and the processor being used to call and run the computer program stored in the memory to execute the control method of the power converter as described in the first aspect or any possible implementation of the first aspect.

[0032] In a fourth aspect, an embodiment of the present invention provides a power converter, comprising conversion units corresponding to three phases respectively and a control device as described in the third aspect; the conversion unit is controlled by the control device.

[0033] In a fifth aspect, an embodiment of the present invention provides a power supply device, comprising the power converter as described in the fourth aspect.

[0034] In a sixth aspect, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the power converter control method described in the first aspect or any possible implementation method of the first aspect are implemented.

[0035] The embodiment of the present invention provides a control method, device, control equipment and power converter of a power converter. When the modulation wave fundamental wave of any phase is within the zero-crossing clamping interval, the modulation wave fundamental waves of the three phases are all added with the opposite number of the middle value of the modulation wave fundamental waves of the three phases, so that the modulation wave fundamental waves within the zero-crossing clamping interval can be clamped to 0, so that when the input current passes through the zero point, the modulation wave also passes through the zero point, which can avoid the input current from being distorted when passing through the zero point, affecting the output current quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1is a schematic diagram of a zero-crossing clamping interval provided by an embodiment of the present invention;

[0038] Figure 2 is a flow chart of an implementation method of a power converter control method provided by an embodiment of the present invention;

[0039] Figure 3 is a schematic diagram of a modulation wave fundamental wave, a modulation wave and an output current provided by an embodiment of the present invention;

[0040] Figure 4 is a schematic structural diagram of a control device for a power converter provided by an embodiment of the present invention;

[0041] Figure 5 is a schematic diagram of a control device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below in conjunction with the accompanying drawings.

[0044] As mentioned above, the power converter can convert AC power into DC power and can be controlled by DPWM method. When the power converter is controlled by DPWM method, there is a certain phase difference between the modulation wave and the input current, such as Figure 1 As shown, the input current 12 lags slightly behind the modulation wave 11. When the input current 12 passes through the zero point, the modulation wave 11 has already reversed. In this case, it is easy to cause the input current to be distorted when passing through the zero point, thereby affecting the quality of the output current.

[0045] In order to solve the above problems, an embodiment of the present application provides a control method for a power converter.

[0046] See also Figure 2 , which shows an implementation flow chart of a control method for a power converter provided by an embodiment of the present invention, and the execution subject of the control method for the power converter is a control device.

[0047] The control method of the power converter is described in detail as follows:

[0048] In S201 , a three-phase modulation wave fundamental wave of a power converter is obtained.

[0049] The three-phase modulation wave fundamental wave of the power converter includes the modulation wave fundamental wave of the A phase, the modulation wave fundamental wave of the B phase and the modulation wave fundamental wave of the C phase of the power converter.

[0050] The fundamental wave of the modulation wave of each phase can be a sine wave, which can be understood as a sine wave signal with the same frequency as the desired output sine wave voltage.

[0051] In the embodiment of the present application, by adjusting the fundamental wave of the modulation wave of each phase, the modulation wave of each phase can be obtained, so that the modulation wave of each phase is in phase with the input current of each phase.

[0052] In S202, if the modulation wave fundamental of any phase is within the zero-crossing clamping interval, the modulation wave fundamentals of the three phases are added with the first zero-sequence component to obtain the three-phase modulation wave; the first zero-sequence component is the opposite of the middle value of the modulation wave fundamental of the three phases.

[0053] See also Figure 1 , the zero-crossing clamping interval is Figure 1 The interval indicated by θ shown in the figure can be the angle interval corresponding to each time when the upper and lower envelopes of the input current ripple cross the zero point. The zero-crossing clamping interval includes the angle corresponding to each zero-crossing point of the input current. Specifically, Figure 1 In the figure, 13 is the upper envelope of the input current ripple, 14 is the lower envelope of the input current ripple, Figure 1 The leftmost zero-crossing clamping interval starts from the zero-crossing point of the upper envelope 13 of the input current ripple and ends at the zero-crossing point of the lower envelope 14 of the input current ripple. The middle zero-crossing clamping interval starts from the zero-crossing point of the lower envelope 14 of the input current ripple and ends at the zero-crossing point of the upper envelope 13 of the input current ripple. The rightmost zero-crossing clamping interval starts from the zero-crossing point of the upper envelope 13 of the input current ripple and ends at the zero-crossing point of the lower envelope 14 of the input current ripple.

[0054] In an embodiment of the present application, when the modulation wave fundamental wave of any phase among the modulation wave fundamental wave of phase A, the modulation wave fundamental wave of phase B and the modulation wave fundamental wave of phase C is located in the zero-crossing clamping interval, in order to make the modulation wave corresponding to the modulation wave fundamental wave in the zero-crossing clamping interval also cross zero when the input current of the same phase crosses zero, the first zero-sequence component is added to the modulation wave fundamental wave of each phase, that is, the opposite of the middle value in the modulation wave fundamental wave of each phase is added to obtain the modulation wave of each phase, so that the modulation wave corresponding to the modulation wave fundamental wave located in the zero-crossing clamping interval is clamped to 0 in the zero-crossing clamping interval, and the zero-crossing clamping interval includes the zero-crossing point of the input current. Therefore, it is achieved that the modulation wave of the same phase also crosses zero at the zero-crossing point of the input current.

[0055] Among them, the middle value of the modulation wave fundamental of the three phases refers to the value of the modulation wave fundamental whose size relationship among the waveform values ​​of the modulation wave fundamental of phase A, the modulation wave fundamental of phase B and the modulation wave fundamental of phase C is in the middle. The opposite number of the middle value of the modulation wave fundamental of the three phases is the value obtained by adding a minus sign in front of the middle value of the modulation wave fundamental of the three phases. For example, assuming that the value of the modulation wave fundamental of phase A corresponding to a certain angle is D1, the value of the modulation wave fundamental of phase B is D2, the value of the modulation wave fundamental of phase C is D3, and D1>D2>D3, then the middle value of the modulation wave fundamental of the three phases corresponding to the angle is the value D2 of the modulation wave fundamental of phase B.

[0056] It should be noted that the intermediate value in the fundamental wave of the three-phase modulation wave is not fixed, but changes with the change of the angle of the zero-crossing clamping interval. Therefore, the value of the first zero-sequence component also changes with the change of the angle of the zero-crossing clamping interval. Each angle in the zero-crossing clamping interval corresponds to an intermediate value mentioned above, and accordingly, at this angle, the first zero-sequence component is the opposite of the intermediate value.

[0057] Since the modulation wave fundamentals of the three phases have a certain phase difference, that is, the modulation wave fundamentals of phase A, phase B and phase C are 120 degrees apart, when the modulation wave fundamental of a phase is within the zero-crossing clamping interval, the middle value of the modulation wave fundamentals of the three phases is also the modulation wave fundamental within the zero-crossing clamping interval. Based on this, the modulation wave fundamental within the zero-crossing clamping interval plus the opposite number of the above middle value is exactly 0.

[0058] To sum up, through the method provided in the embodiment of the present application, the modulation wave of any phase is clamped to 0 within the zero-crossing clamping interval. Therefore, when the input current of the same phase passes through zero, the modulation wave of the same phase also passes through zero, and there is no phase difference. Therefore, the input current will not be distorted when passing through the zero point, and the output current quality is also good.

[0059] In S203 , the power converter is controlled based on the three-phase modulation wave.

[0060] The three-phase modulation wave includes a modulation wave of an A phase, a modulation wave of a B phase, and a modulation wave of a C phase.

[0061] The embodiment of the present application controls the power converter based on the modulation wave of phase A, the modulation wave of phase B and the modulation wave of phase C, so that the input current will not be distorted when passing through the zero point and the output current quality is also good.

[0062] In some possible implementations, the above S203 may include: comparing the three-phase modulation wave with the carrier wave to generate a three-phase PWM wave, and controlling the power converter according to the three-phase PWM wave.

[0063] In the embodiment of the present application, when the modulation wave fundamental of any phase is within the zero-crossing clamping interval, the modulation wave fundamentals of the three phases are added with the opposite number of the middle value of the modulation wave fundamentals of the three phases, so that the modulation wave fundamentals within the zero-crossing clamping interval can be clamped to 0, so that when the input current passes through the zero point, the modulation wave also passes through the zero point, which can avoid the input current from being distorted when passing through the zero point, affecting the output current quality.

[0064] In the above-mentioned embodiment, the zero-crossing clamping interval is mentioned, and the selection of the zero-crossing clamping interval is also very important. If the zero-crossing clamping interval is too small, it may not play the role of clamping. If the zero-crossing clamping interval is too large, it will cause the midpoint voltage of the power converter to be uncontrollable, affecting the efficiency of the power converter. In response to this problem, how to determine the zero-crossing clamping interval is described in detail below.

[0065] In some embodiments, before the above S202, the above power converter control method may further include:

[0066] Obtaining three-phase input current and input current ripple of the power converter;

[0067] Based on the three-phase input current, determine the D-axis component, Q-axis component and peak value of the input current;

[0068] The zero-crossing clamping interval is determined based on the D-axis component, the Q-axis component, the peak value, and the input current ripple.

[0069] In an embodiment of the present application, based on the three-phase input current, the D-axis component of the input current and the Q-axis component of the input current can be determined by Clark transformation and / or Park transformation. The peak value of the input current can be determined by the three-phase input current. According to the D-axis component of the input current, the Q-axis component of the input current, the peak value of the input current and the input current ripple, the zero-crossing clamping interval can be accurately determined.

[0070] In some embodiments, the zero-crossing clamping interval includes:

[0071]

[0072] Where Iripple is the input current ripple; Iq is the Q-axis component; Id is the D-axis component; I PK is the peak value; k is an integer.

[0073] Among them, k can be any integer, k =…,-3,-2,-2-1,0,1,2,3,….

[0074] The zero-crossing clamping interval determined in the embodiment of the present application is neither too small to play the role of zero-crossing clamping, nor too large to affect the efficiency of the power converter.

[0075] The output of the power converter may include a positive bus, a negative bus and a neutral line. A first capacitor is connected between the positive bus and the midpoint, and a second capacitor is connected between the negative bus and the midpoint. The voltage between the positive bus and the midpoint is the upper bus voltage of the power converter, that is, the voltage across the first capacitor is the upper bus voltage; the voltage between the midpoint and the negative bus is the lower bus voltage of the power converter, that is, the voltage across the second capacitor is the lower bus voltage. In order to improve the efficiency of the power converter, it is necessary to maintain the midpoint balance, that is, the absolute value of the upper bus voltage is equal to the absolute value of the lower bus voltage. However, in practical applications, the two are usually not equal. How to solve this problem is described in detail below.

[0076] In some embodiments, after the above S201, the above power converter control method may further include:

[0077] If the fundamental waves of the modulation waves of the three phases are not within the zero-crossing clamping interval, the upper half bus voltage and the lower half bus voltage of the power converter are obtained;

[0078] Compare the absolute value of the upper bus voltage with the absolute value of the lower bus voltage to obtain a comparison result;

[0079] Determine the second zero-sequence component according to the comparison result and the fundamental wave of the modulation wave of the three phases;

[0080] The second zero-sequence component is added to the three-phase modulation wave fundamental waves to obtain the three-phase modulation wave, and the step of controlling the power converter based on the three-phase modulation wave is executed.

[0081] In the embodiment of the present application, in order to avoid distortion at the zero-crossing point, when the modulation wave fundamental wave of any phase is located in the zero-crossing clamping interval, the modulation wave fundamental waves of the three phases are all added with the first zero-sequence component; in order to maintain the midpoint balance and improve the efficiency of the power converter, when the modulation wave fundamental waves of the three phases are not located in the zero-crossing clamping interval, the modulation wave fundamental waves of the three phases are all added with the second zero-sequence component, thereby obtaining the three-phase modulation wave. Wherein, the second zero-sequence component is determined based on the comparison result of the absolute value of the upper half bus voltage of the power converter and the absolute value of the lower half bus voltage of the power converter, as well as the modulation wave fundamental waves of the three phases.

[0082] It should be noted that, in the embodiment of the present application, the first zero-sequence component and the second zero-sequence component are zero-sequence components that need to be added to the fundamental wave of the modulation wave of the three phases, but the first zero-sequence component is the zero-sequence component that needs to be added when the fundamental wave of the modulation wave of any phase is located in the zero-crossing clamping interval, and the second zero-sequence component is the zero-sequence component that needs to be added when the fundamental wave of the modulation wave of the three phases is not located in the zero-crossing clamping interval. In other words, in each zero-crossing clamping interval, the values ​​of the fundamental wave of the modulation wave of the three phases corresponding to each angle in the zero-crossing clamping interval need to be added with the first zero-sequence component, and in each non-zero-crossing clamping interval, the values ​​of the fundamental wave of the modulation wave of the three phases corresponding to each angle in the non-zero-crossing clamping interval need to be added with the second zero-sequence component, thereby obtaining a three-phase modulation wave.

[0083] In some embodiments, the second zero-sequence component is determined according to the comparison result and the fundamental wave of the three-phase modulation wave, including:

[0084] If the comparison result is that the absolute value of the upper half bus voltage is greater than the absolute value of the lower half bus voltage, the second zero-sequence component is determined based on the minimum value of the fundamental wave of the three-phase modulation wave;

[0085] If the comparison result is that the absolute value of the upper half bus voltage is smaller than the absolute value of the lower half bus voltage, the second zero-sequence component is determined based on the maximum value of the fundamental wave of the three-phase modulation wave.

[0086] If the comparison result is that the absolute value of the upper half bus voltage is equal to the absolute value of the lower half bus voltage, the second zero-sequence component is 0.

[0087] The minimum value of the three-phase modulation wave fundamental wave is the smallest value of the modulation wave fundamental wave in the magnitude relationship among the waveform values ​​of the modulation wave fundamental wave of phase A, the modulation wave fundamental wave of phase B and the modulation wave fundamental wave of phase C. The maximum value of the three-phase modulation wave fundamental wave is the largest value of the modulation wave fundamental wave in the magnitude relationship among the waveform values ​​of the modulation wave fundamental wave of phase A, the modulation wave fundamental wave of phase B and the modulation wave fundamental wave of phase C.

[0088] It should be noted that, within the non-zero-crossing clamping interval, the minimum value of the modulation wave fundamental wave of the three phases and the maximum value of the modulation wave fundamental wave of the three phases are not fixed, but change with the change of the angle of the non-zero-crossing clamping interval. Each angle within the non-zero-crossing clamping interval corresponds to one of the above maximum values ​​and one of the above minimum values.

[0089] In some embodiments, the calculation formula of the second zero-sequence component m2 is:

[0090]

[0091] Among them, m min is the minimum value of the three-phase modulation wave fundamental wave; m max is the maximum value of the three-phase modulation wave fundamental wave; UCp is the upper bus voltage; U Cn is the lower half bus voltage.

[0092] The embodiments of the present application can not only avoid distortion caused by zero crossing, but also maintain midpoint balance and improve the efficiency of the power converter.

[0093] In some embodiments, the power converter is an AC-DC converter; and the fundamental wave of the modulation wave is a sine wave.

[0094] Exemplarily, the power converter may be a three-phase Vienna converter, or may be another type of AC-DC converter, which is not specifically limited herein.

[0095] See also Figure 3 , Figure 3 The three waveforms from top to bottom are respectively the fundamental wave of the modulation wave, the modulation wave obtained by adopting the method provided by the present application, and the output current obtained by adopting the method provided by the present application. Figure 3 It can be seen that the modulation wave is clamped to 0 in the zero-crossing clamping interval, and the output current quality is also good.

[0096] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0097] Figure 4 The following is a schematic diagram showing the structure of a control device for a power converter provided by an embodiment of the present invention. For ease of explanation, only the parts related to the embodiment of the present invention are shown, which are described in detail as follows:

[0098] like Figure 4 As shown, the control device 30 of the power converter includes: an acquisition module 31 , a modulation wave determination module 32 and a control module 33 .

[0099] Wherein, the acquisition module 31 is used to obtain the three-phase modulation wave fundamental of the power converter;

[0100] The modulation wave determination module 32 is used for adding the first zero-sequence component to the modulation wave fundamentals of the three phases to obtain the modulation waves of the three phases if the modulation wave fundamental of any phase is within the zero-crossing clamping interval; the first zero-sequence component is the opposite number of the middle value of the modulation wave fundamental of the three phases;

[0101] The control module 33 is used to control the power converter based on the three-phase modulation wave.

[0102] In a possible implementation, the control device 30 of the power converter further includes: a zero-crossing clamping interval determination module.

[0103] The zero-crossing clamping interval determination module is used for: if the modulation wave fundamental wave of any phase is within the zero-crossing clamping interval, the modulation wave fundamental waves of the three phases are all added with the first zero-sequence component to obtain the three-phase modulation wave, and then the three-phase input current and input current ripple of the power converter are obtained; based on the three-phase input current, the D-axis component, Q-axis component and peak value of the input current are determined; based on the D-axis component, Q-axis component, peak value and input current ripple, the zero-crossing clamping interval is determined.

[0104] In a possible implementation, the zero-crossing clamping interval includes:

[0105]

[0106] Where Iripple is the input current ripple; Iq is the Q-axis component; Id is the D-axis component; I PK is the peak value; k is an integer.

[0107] In a possible implementation, the modulation wave determination module 32 is further configured to:

[0108] If the fundamental waves of the modulation waves of the three phases are not within the zero-crossing clamping interval, the upper half bus voltage and the lower half bus voltage of the power converter are obtained;

[0109] Compare the absolute value of the upper bus voltage with the absolute value of the lower bus voltage to obtain a comparison result;

[0110] Determine the second zero-sequence component according to the comparison result and the fundamental wave of the modulation wave of the three phases;

[0111] The second zero-sequence component is added to the three-phase modulation wave fundamental waves to obtain the three-phase modulation wave, and the step of controlling the power converter based on the three-phase modulation wave is executed.

[0112] In a possible implementation, in the modulation wave determination module 32, determining the second zero-sequence component according to the comparison result and the modulation wave fundamental wave of the three phases includes:

[0113] If the comparison result is that the absolute value of the upper half bus voltage is greater than the absolute value of the lower half bus voltage, the second zero-sequence component is determined based on the minimum value of the fundamental wave of the three-phase modulation wave;

[0114] If the comparison result is that the absolute value of the upper half bus voltage is smaller than the absolute value of the lower half bus voltage, the second zero-sequence component is determined based on the maximum value of the fundamental wave of the three-phase modulation wave.

[0115] In a possible implementation, the calculation formula of the second zero-sequence component m2 is:

[0116]

[0117] Among them, m minis the minimum value of the three-phase modulation wave fundamental wave; m max is the maximum value of the three-phase modulation wave fundamental wave; U Cp is the upper bus voltage; U Cn is the lower half bus voltage.

[0118] In a possible implementation, the power converter is an AC-DC converter; and the fundamental wave of the modulation wave is a sine wave.

[0119] Figure 5 Schematic diagram of a control device provided by an embodiment of the present invention. Figure 5 As shown, the control device 4 of this embodiment includes: a processor 40 and a memory 41. The memory 41 is used to store a computer program 42, and the processor 40 is used to call and run the computer program 42 stored in the memory 41 to perform the steps in the above-mentioned control method embodiments of each power converter, such as Figure 2 Alternatively, the processor 40 is used to call and run the computer program 42 stored in the memory 41 to implement the functions of each module / unit in the above-mentioned device embodiments, for example Figure 4 The functions of each module are shown.

[0120] Exemplarily, the computer program 42 may be divided into one or more modules / units, which are stored in the memory 41 and executed by the processor 40 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program 42 in the control device 4. For example, the computer program 42 may be divided into Figure 4 The modules shown.

[0121] The control device 4 may include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will appreciate that Figure 5 It is only an example of the control device 4 and does not constitute a limitation of the control device 4. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the control device may also include input and output devices, network access devices, buses, etc.

[0122] The processor 40 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0123] The memory 41 may be an internal storage unit of the control device 4, such as a hard disk or memory of the control device 4. The memory 41 may also be an external storage device of the control device 4, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the control device 4. Further, the memory 41 may also include both an internal storage unit and an external storage device of the control device 4. The memory 41 is used to store the computer program and other programs and data required by the control device. The memory 41 may also be used to temporarily store data that has been output or is to be output.

[0124] Corresponding to the above-mentioned control device, an embodiment of the present invention further provides a power converter, comprising conversion units corresponding to three phases respectively and the above-mentioned control device; the conversion unit is controlled by the control device.

[0125] The conversion units corresponding to the three phases include a phase A conversion unit, a phase B conversion unit and a phase C conversion unit. The control device can control each phase based on the modulation wave of each phase.

[0126] Corresponding to the above-mentioned power converter, an embodiment of the present application further provides a power supply device, including the above-mentioned power converter.

[0127] For the relevant description of the power converter and the power supply device, reference may be made to the description in the aforementioned embodiments and will not be repeated here.

[0128] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0129] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0130] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0131] In the embodiments provided by the present invention, it should be understood that the disclosed devices / control equipment and methods can be implemented in other ways. For example, the device / control equipment embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0132] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0133] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0134] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the control method embodiments of each power converter can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0135] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A control method for a power converter, characterized in that: include: Obtaining a three-phase modulation wave fundamental wave of the power converter; If the modulation wave fundamental wave of any phase is within the zero-crossing clamping interval, the modulation wave fundamental waves of the three phases are all added with the first zero-sequence component to obtain the modulation wave of the three phases; the first zero-sequence component is the opposite number of the middle value of the modulation wave fundamental wave of the three phases; The power converter is controlled based on the three-phase modulation wave.

2. The control method of the power converter according to claim 1, characterized in that: Before the method of adding the first zero-sequence component to the modulation wave fundamental waves of the three phases to obtain the modulation waves of the three phases if the modulation wave fundamental wave of any phase is within the zero-crossing clamping interval, the method further includes: Obtaining a three-phase input current and an input current ripple of the power converter; Based on the three-phase input current, determining a D-axis component, a Q-axis component and a peak value of the input current; A zero-crossing clamping interval is determined based on the D-axis component, the Q-axis component, the peak value, and the input current ripple.

3. The control method of the power converter according to claim 2, characterized in that: The zero-crossing clamping interval includes: Wherein, Iripple is the input current ripple; Iq is the Q-axis component; Id is the D-axis component; I PK is the peak value; k is an integer.

4. The control method of the power converter according to claim 1, characterized in that: After obtaining the three-phase modulation wave fundamental of the power converter, the method further includes: If the fundamental waves of the modulation waves of the three phases are not within the zero-crossing clamping interval, then obtaining the upper half bus voltage and the lower half bus voltage of the power converter; Comparing the absolute value of the upper half bus voltage with the absolute value of the lower half bus voltage to obtain a comparison result; Determine a second zero-sequence component according to the comparison result and the fundamental wave of the modulation wave of the three phases; The second zero-sequence component is added to the three-phase modulation wave fundamental waves to obtain the three-phase modulation wave, and the step of controlling the power converter based on the three-phase modulation wave is performed.

5. The control method of the power converter according to claim 4, characterized in that: The determining of the second zero-sequence component according to the comparison result and the modulation wave fundamental of the three-phase comprises: If the comparison result is that the absolute value of the upper half bus voltage is greater than the absolute value of the lower half bus voltage, determining the second zero-sequence component based on the minimum value of the fundamental wave of the modulation wave of the three phases; If the comparison result is that the absolute value of the upper half bus voltage is smaller than the absolute value of the lower half bus voltage, the second zero-sequence component is determined based on the maximum value of the fundamental wave of the three-phase modulation wave.

6. The control method of the power converter according to claim 5, characterized in that: The calculation formula of the second zero-sequence component m2 is: Among them, m min is the minimum value of the fundamental wave of the three-phase modulation wave; m max is the maximum value of the fundamental wave of the three-phase modulation wave; U Cp is the upper half bus voltage; U Cn is the lower half bus voltage.

7. The control method of a power converter according to any one of claims 1 to 6, characterized in that: The power converter is an AC-DC converter; the modulation wave fundamental wave is a sine wave.

8. A control device for a power converter, characterized in that: include: An acquisition module, used for acquiring the three-phase modulation wave fundamental of the power converter; A modulation wave determination module, for adding a first zero-sequence component to the modulation wave fundamentals of the three phases to obtain a modulation wave of the three phases if the modulation wave fundamental of any phase is within the zero-crossing clamping interval; the first zero-sequence component is the opposite number of the middle value of the modulation wave fundamental of the three phases; A control module is used to control the power converter based on the three-phase modulation wave.

9. A control device, characterized in that: It comprises a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the control method of the power converter as claimed in any one of claims 1 to 7.

10. A power converter, characterized in that: It comprises conversion units corresponding to the three phases respectively and a control device as claimed in claim 9; the conversion units are controlled by the control device.

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