Overmodulation control method and module for motor control and medium

Abstract

The invention provides an overmodulation control method and module for motor control and a medium, and relates to the technical field of motor control, and the method comprises the steps: obtaining a modulation ratio and a voltage vector angle, and constructing an initial three-phase modulation wave which is a three-phase modulation wave with the modulation ratio of 1 obtained after a common-mode component is injected into carrier modulation; rotating by 90 degrees based on the initial three-phase modulation wave and acquiring a voltage gain associated with the initial three-phase modulation wave so as to generate a three-phase voltage signal wave; when the voltage signal value of each phase in the three-phase voltage signal wave does not exceed + / -1, the inverter performs modulation based on a modulation ratio; when only one phase value of each phase voltage signal wave in the three-phase voltage signal waves exceeds + / -1, the inverter determines the gain of the exceeding part according to the three-phase voltage signal waves so as to carry out modulation; when more than one phase value of each phase voltage signal wave in the three-phase voltage signal waves exceeds + / -1, the inverter outputs a basic voltage vector, and the problems that the harmonic content of an existing overmodulation algorithm is large, and smooth transition to square waves cannot be achieved are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to an overmodulation control method, module and medium for motor control. Background Art

[0002] SVPWM overmodulation is a modulation technology used in the field of motor control. Its core purpose is to further improve the performance of the motor drive system when the limit of the conventional linear modulation area is exceeded. Under the conventional linear modulation state, the waveform of the pulse width modulation signal maintains a shape similar to that of a sine wave. When the modulation index exceeds 100%, that is, it enters the overmodulation area, the voltage waveform of each phase begins to deviate significantly from the sine waveform, with more step-like edges and wider pulse widths, and even approaches a square wave in extreme cases.

[0003] There are usually some control algorithms to achieve overmodulation, including adjustment of the reference voltage vector amplitude and control of the nonlinear voltage waveform, such as single-mode overmodulation strategy, dual-mode minimum amplitude error modulation strategy, dual-mode minimum phase error modulation strategy, etc. However, most of the existing modulation strategies have a lot of harmonic content and most of them cannot smoothly transition to square waves, which has a great impact on modulation accuracy, equipment performance loss, etc. Summary of the invention

[0004] In order to overcome the above technical defects, the purpose of the present invention is to provide a method to solve the problem that the existing overmodulation algorithm has a large amount of harmonics and cannot smoothly transition to a square wave.

[0005] The present invention discloses an overmodulation control method for motor control, comprising:

[0006] Acquire the modulation ratio and the voltage vector angle to construct an initial three-phase modulation wave, wherein the initial three-phase modulation wave is a three-phase modulation wave with a modulation ratio of 1 obtained by injecting a common mode component into the carrier wave for modulation;

[0007] Presetting voltage gains associated with each modulation ratio, rotating the initial three-phase modulation wave by 90° at a voltage vector angle and obtaining voltage gains associated therewith to generate a three-phase voltage signal wave;

[0008] When the voltage signal value of each phase in the three-phase voltage signal wave does not exceed ±1, the inverter performs modulation based on the modulation ratio;

[0009] When only one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1, the inverter determines the gain of the exceeding part of the reference voltage vector according to the three-phase voltage signal wave for modulation;

[0010] When more than one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1, the inverter outputs a basic voltage vector.

[0011] Preferably, determining the gain of the excess portion of the reference voltage vector according to the three-phase voltage signal wave comprises:

[0012] Determine in advance the gain of the excess part of the reference voltage vector corresponding to different sectors according to the voltage vector synthesis range and the maximum range of linear modulation by using the minimum phase error method;

[0013] When only one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1, the sector of the voltage vector synthesis range where the reference voltage vector is located is determined, thereby determining the gain of the exceeding portion.

[0014] Preferably, the inverter determines the gain of the excess part of the reference voltage vector according to the three-phase voltage signal wave for modulation, including:

[0015] The initial three-phase modulation wave is multiplied by the inverse of the gain of the excess portion to perform modulation.

[0016] Preferably, when only the A-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds 1, it is determined that the reference voltage vector is located in the second sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(π / 2-θ);

[0017] When the voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds -1, it is determined that the reference voltage vector is located in the fifth sector of the voltage vector synthesis range, and the gain of the corresponding exceeding part is cos(3π / 2-θ);

[0018] When only the B-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds 1, it is determined that the reference voltage vector is located in the fourth sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(7π / 6-θ);

[0019] When the voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds -1, it is determined that the reference voltage vector is located in the first sector of the voltage vector synthesis range, and the gain of the corresponding exceeding part is cos(π / 6-θ);

[0020] When only the C-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds 1, it is determined that the reference voltage vector is located in the sixth sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(-π / 6-θ);

[0021] When only the C-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds -1, it is determined that the reference voltage vector is located in the third sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(5π / 6-θ).

[0022] Preferably, for a three-phase voltage signal, when the voltage signal value is positive, 1 is output, and when the voltage signal value is negative, 0 is output, so as to output a basic voltage vector.

[0023] Preferably, for any phase voltage signal whose value exceeds ±1, when the voltage signal value exceeds 1, 1 is output, and when the voltage signal value exceeds -1, 0 is output accordingly.

[0024] Preferably, when the voltage signal value of each phase in the three-phase voltage signal wave does not exceed ±1, the inverter is in a linear modulation mode;

[0025] When only one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1, the inverter is in the modulation zone I mode;

[0026] When more than one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1, the inverter is in the modulation zone II mode.

[0027] The present invention also provides an overmodulation control module for motor control, comprising a memory and a processor, for executing the steps of any of the overmodulation control methods described above.

[0028] The present invention also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of any of the above-mentioned overmodulation control methods are implemented.

[0029] Compared with the prior art, the above technical solution has the following beneficial effects:

[0030] The overmodulation control method, module and medium of motor control provided in the present application combine the minimum phase error principle and carrier modulation, construct an initial three-phase modulation wave with a modulation ratio of 1 based on carrier modulation, and generate a three-phase voltage signal wave according to the voltage gain after rotating it 90°, compare it (per-unit value) with ±1, and if it does not exceed ±1, it is determined to be in the linear modulation area, and carrier modulation is relied on; if it exceeds ±1, it is determined to be in the overmodulation area; if only one phase exceeds, it is determined to be in modulation area I, and modulation is performed based on the initial three-phase modulation wave multiplied by the gain corresponding to the exceeded part; if more than one phase exceeds, it is determined to be in modulation area II, and a square wave is directly output, and carrier modulation compatible with the original linear modulation area is realized through logic control, and the output voltage signal wave is smaller than the original harmonic in the overmodulation interval, and can smoothly transition to a square wave in modulation area II and the running time is short, thereby solving the problem that the existing overmodulation algorithm has a large harmonic content and cannot smoothly transition to a square wave. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of an embodiment 1 of an overmodulation control method, module and medium for motor control according to the present invention;

[0032] Figure 2 A schematic diagram of a three-phase voltage signal wave in Embodiment 1 of an overmodulation control method, module and medium for motor control according to the present invention;

[0033] Figure 3 The output waveform diagram of the overmodulation control method, module and medium for motor control in the first embodiment of the present invention after modulation when each phase voltage signal wave in the three-phase voltage signal wave has and only has one phase value exceeding ±1;

[0034] Figure 4 The output waveform diagram of the overmodulation control method, module and medium for motor control in Embodiment 1 of the present invention after modulation when more than one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1;

[0035] Figure 5 A schematic diagram comparing the total harmonic distortion of the overmodulation control method, module and medium of motor control described in the present invention with the existing carrier modulation. DETAILED DESCRIPTION

[0036] The advantages of the present invention are further described below in conjunction with the accompanying drawings and specific embodiments.

[0037] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0038] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. The singular forms of "a", "said" and "the" used in this disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0039] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0040] In the description of the present invention, it is necessary to understand that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0041] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0042] In the following description, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present invention, and have no specific meanings. Therefore, "module" and "component" can be used interchangeably.

[0043] Embodiment 1: This embodiment discloses an overmodulation control method for motor control. It can be understood that the overmodulation control synthesizes a rotating space voltage vector by changing the conduction state and duration of the switching device to control the inverter to output a voltage wave close to a sine wave. In this embodiment, the overmodulation algorithm is implemented by combining the minimum phase error principle and the carrier-modulated SVPWM. As an explanation, the geometric figure formed by the switching of the different switching modes of the three-phase inverter on the complex plane is called a voltage vector hexagon or a space vector hexagon. In the absence of overmodulation, the voltage vector range that the inverter can output is limited to its maximum inscribed circle. The area between the circumscribed circle of the hexagon and the inscribed circle (overmodulation zone I) and outside constitutes the overmodulation area (overmodulation zone II). The circumscribed circle defines the boundary of the overmodulation area. When the reference voltage vector exceeds the inscribed circle but is still inside the circumscribed circle of the hexagon, overmodulation occurs.

[0044] Based on the above, see Figure 1 , the overmodulation control method of this embodiment includes:

[0045] S10: Acquire the modulation ratio m and the voltage vector angle θ to construct an initial three-phase modulation wave, wherein the initial three-phase modulation wave is a three-phase modulation wave with a modulation ratio of 1 obtained by injecting a common mode component into the carrier wave for modulation;

[0046] It can be understood that in this embodiment, the existing carrier injection common mode component modulation method is used to construct the initial three-phase modulation wave. Carrier modulation injection common mode component is a common technology used to improve system performance in inverter control, which can effectively suppress common mode voltage and reduce switching loss. The modulation ratio is the ratio of the amplitude of the reference voltage vector to the radius of the inscribed circle. When the modulation ratio is 1, the amplitude of the reference voltage vector is equal to the radius of the inscribed circle. At this time, the line voltage amplitude of the inverter output is equal to the DC voltage U dc , the initial three-phase modulation wave has a modulation ratio of 1 and a voltage vector angle of θ.

[0047] S20: presetting voltage gains associated with each modulation ratio, rotating the initial three-phase modulation wave by 90° at a voltage vector angle and obtaining voltage gains associated therewith to generate a three-phase voltage signal wave;

[0048] It should be noted that the above voltage gain is the gain (ratio) between the reference voltage and the output voltage. The modulation ratio is the ratio of the modulation wave to the carrier in the PWM signal, which determines the relationship between the effective value of the inverter output voltage and the DC bus voltage. Ideally, the voltage gain is proportional to the modulation ratio. As the modulation ratio increases, the effective value of the inverter output voltage will also increase, thereby increasing the voltage gain. In the case of overmodulation, the modulation ratio exceeds 100%, and the effective value of the inverter output voltage can exceed the maximum value under linear modulation (undistorted modulation).

[0049] In this embodiment, the voltage gain associated with each modulation ratio is calculated in advance and obtained according to the modulation ratio ( Figure 1 The modulation gain is obtained by looking up the table in the middle, and the three-phase wave (i.e., the three-phase voltage signal wave) is obtained, thereby improving the data processing efficiency without the need for calculation during the processing.

[0050] The generated three-phase voltage signal wave is generated by converting the initial three-phase modulation wave multiplied by the voltage gain associated therewith. In this embodiment, the initial three-phase modulation wave is phase-shifted and then multiplied by the voltage gain associated therewith, and the three-phase voltage signal wave is generated by Clark transformation and Park transformation.

[0051] It can be understood that the above-mentioned three-phase voltage signal wave will obtain a signal greater than 1 or less than -1 due to the rotation of 90°. When the voltage signal values ​​of each phase in the three-phase voltage signal wave do not exceed ±1 (that is, the signal value is between -1 and 1), the inverter is in a linear (undistorted) modulation mode; when the amplitude of each phase voltage signal wave in the three-phase voltage signal wave has and only one phase exceeds 1, the inverter is in the modulation zone I mode (that is, the reference voltage vector is located between the inscribed circle and the circumscribed circle of the hexagon of the voltage vector); when the amplitude of more than one phase of the voltage signal wave in the three-phase voltage signal wave exceeds 1, the inverter is in the modulation zone II mode (that is, the reference voltage vector is located outside the circumscribed circle of the hexagon of the voltage vector).

[0052] The modulation wave is usually composed of three sine waves with a phase difference of 120°, which are compared with a fixed carrier (usually an isosceles triangle wave) to generate a PWM signal. When the amplitude of the modulation wave (modulation ratio M) increases, its peak value will also increase, which may cause the value of the modulation wave to exceed the range that the PWM modulator can handle (that is, beyond ±1) at certain phases. Based on this, the generation of Figure 2 The waveform diagram shown in the figure, where Ua, Ub, and Uc are three-phase voltages with a phase difference of 90°. H1 and H2 are 1 and -1 respectively, based on the comparison between the three-phase voltage signal wave (sine wave) and ±1.

[0053] It can be understood that the above three-phase voltage signal wave reflects the per-unit value of the phase voltage in the three-phase inverter (which can be compared with positive and negative 1 in the following). In the three-phase inverter, the DC bus voltage Udc is converted into a three-phase AC voltage by the inverter. Since the output of the three-phase inverter is the line voltage, the relationship between the line voltage and the phase voltage is times, so the per-unit value of the phase voltage can be obtained by Sure.

[0054] S31: When the voltage signal value of each phase in the three-phase voltage signal wave does not exceed ±1, the inverter performs modulation based on the modulation ratio (that is, the number of the three-phase voltage signal waves exceeding ±1 is 0);

[0055] As mentioned above, when the amplitude of each phase voltage signal does not exceed 1, it is in linear modulation mode, that is, it has not entered the overmodulation area. At this time, SVPWM modulation is realized by carrier modulation. Specifically, the three-phase voltages of A, B, and C are expressed as:

[0056] U a = m sin wt

[0057] Where, m is the modulation ratio;

[0058]

[0059] Injection of zero sequence component

[0060] The inverter performs modulation based on the initial three-phase modulation wave multiplied by the modulation ratio. Through this modulation, the DC bus voltage can be more fully utilized, a larger voltage vector amplitude can be output, the harmonic components of the motor current can be reduced, and the motor operation stability can be improved.

[0061] S32: When only one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1, the inverter determines the gain of the exceeding part of the reference voltage vector according to the three-phase voltage signal wave for modulation (i.e., the number of the three-phase voltage signal wave exceeding ±1 is 1);

[0062] As mentioned above, the motor is in the overmodulation mode and in the overmodulation zone I. In this embodiment, in this state, combined with the minimum phase error principle, modulation is performed by referring to the gain of the voltage vector exceeding the hexagonal part of the voltage vector.

[0063] In this embodiment, the gain of the excess part of the reference voltage vector is determined according to the three-phase voltage signal wave, including: determining the gain of the excess part of the reference voltage vector corresponding to different sectors in advance according to the voltage vector synthesis range (i.e., the above-mentioned voltage vector hexagon) and the maximum range of linear modulation (i.e., the maximum inscribed circle of the above-mentioned hexagon) by the minimum phase error method; when the voltage signal wave of each phase in the three-phase voltage signal wave has and only has one phase value exceeding ±1, determining the sector of the voltage vector synthesis range where the reference voltage vector is located (determined according to which specific phase exceeds 1 or -1), thereby determining the gain of the excess part.

[0064] Specifically, from the perspective of the diagram of overmodulating a sector, when the reference voltage vector exceeds the range of the positive six waveform, the output voltage vector amplitude, output voltage phase angle and reference voltage amplitude, reference voltage angle are related, that is, at the same phase, they only have amplitude differences, so:

[0065] Voltage Vector Hexagon The maximum range of linear modulation (i.e. the maximum inscribed circle of the aforementioned hexagon) is: That is, the increment of the voltage vector angle θ relative to the maximum range of linear modulation can be determined (that is, in the overmodulation I area, the voltage vector hexagon is output, which can be calculated based on the initial three-phase modulation wave (that is, the maximum range of linear modulation)), and the increment is determined in advance based on the voltage vector synthesis range (that is, the above-mentioned voltage vector hexagon) and the maximum range of linear modulation (that is, the maximum inscribed circle of the above-mentioned hexagon) (the ratio of the two is determined Specifically, there is a three-phase voltage signal wave as shown below: That is, when the B-phase voltage signal value is negative (exceeding -1, the excess part is cos(π / 6-θ))

[0066] Based on the above, the following table can be obtained:

[0067] Sector Corresponding value Actual value 1 <![CDATA[-V b ]]> cos(π / 6-θ) 2 <![CDATA[V a ]]> cos(π / 2-θ) 3 <![CDATA[-V c ]]> cos(5π / 6-θ) 4 <![CDATA[V b ]]> cos(7π / 6-θ) 5 <![CDATA[-V a ]]> cos(3π / 2-θ) 6 <![CDATA[V c ]]> cos(-π / 6-θ)

[0068] From this, it can be seen that when the A phase voltage signal value is positive, the reference voltage vector is located in the second sector, and when the A phase voltage signal value is negative, the reference voltage vector is located in the fifth sector. Therefore, phases B and C are similar as shown in the table above.

[0069] Based on the above, when only the A-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds 1, it is determined that the reference voltage vector is located in the second sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(π / 2-θ); when only the A-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds -1, it is determined that the reference voltage vector is located in the fifth sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(3π / 2-θ); when only the B-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds 1, it is determined that the reference voltage vector is located in the fourth sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(7π / 6-θ ); when only the B-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds -1, it is determined that the reference voltage vector is located in the first sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(π / 6-θ); when only the C-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds 1, it is determined that the reference voltage vector is located in the sixth sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(-π / 6-θ); when only the C-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds -1, it is determined that the reference voltage vector is located in the third sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(5π / 6-θ).

[0070] As described above, the gain of the excess portion is predetermined based on the voltage vector synthesis range (ie, the voltage vector hexagon mentioned above) and the maximum range of linear modulation (ie, the maximum inscribed circle of the hexagon mentioned above).

[0071] In this embodiment, the inverter determines the gain of the excess part of the reference voltage vector according to the three-phase voltage signal wave for modulation, including: using the initial three-phase modulation wave multiplied by the inverse of the gain of the excess part to perform modulation. That is, as an example, the initial three-phase modulation wave is multiplied by That is, the maximum linear modulation range multiplied by the inverse of the gain of the excess part.

[0072] If the amplitude of the reference voltage vector exceeds 2 / 3Udc (where Udc is the DC bus voltage), the gain G of the excess portion can be expressed as: In order to limit the amplitude of the reference voltage vector within the modulatable range, the three-phase modulation wave needs to be multiplied by the inverse of G, that is, In this way, the amplitude of the three-phase modulation wave is limited to the range of 2 / 3Udc, thus avoiding over-modulation.

[0073] Based on the above, this method ensures that the output voltage of the inverter is within the modulatable range while maintaining the accuracy of the phase and amplitude of the voltage vector.

[0074] like Figure 3 As shown, Figure 3 The three-phase voltage signal wave processed by the overmodulation method is shown, and the per-unit value of each phase voltage signal wave is within ±1, that is, the overmodulation area is controlled to be within the linear modulation area, that is, within the modulation range.

[0075] S33: When more than one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1, the inverter outputs a basic voltage vector (ie, the number of the three-phase voltage signal waves exceeding ±1 is greater than 1).

[0076] As mentioned above, at this time the motor is in the overmodulation mode and in the overmodulation zone II, that is, the reference voltage vector is outside the circumscribed circle of the hexagon. In this embodiment, the basic voltage vector is directly output to achieve a smooth transition of the inverter output from the sinusoidal wave with harmonics output in the above mode to a square wave.

[0077] In this embodiment, the output of the basic voltage vector includes: when more than one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1, and only two phase voltage signal values ​​in the three-phase voltage signal wave exceed ±1, the inverter outputs the basic voltage vector according to the polarity of each phase voltage signal value. It is determined according to the positive voltage when it exceeds 1 and the negative voltage when it is less than -1. Specifically: for any phase voltage signal whose value exceeds ±1, when the voltage signal value exceeds 1, 1 is output, and when the voltage signal value exceeds -1, 0 is output accordingly; for the voltage signal that does not exceed ±1, when the voltage signal value is positive, 1 is output, and when the voltage signal value is negative, 0 is output accordingly, so as to output the basic voltage vector, that is, for any phase ABC, when the voltage signal value is greater than 0, 1 is output, and when the voltage signal value exceeds -1, 0 is output accordingly, so as to generate the basic voltage vector.

[0078] As an example, if the A-phase voltage signal value exceeds 1 (>1), the C-phase voltage signal value exceeds -1 (<-1), when the B-phase voltage signal value is positive, the basic voltage vector (110) is output, and when the B-phase voltage signal value is negative, the basic voltage vector (100) is output; if the A-phase voltage signal value exceeds 1 (>1), the B-phase voltage signal value exceeds -1 (<-1), when the C-phase voltage signal value is positive, the basic voltage vector (101) is output, and when the C-phase voltage signal value is negative, the basic voltage vector (100) is output; if the A-phase voltage signal value exceeds -1 (<-1), the C-phase voltage signal value exceeds 1 (>1), when the B-phase voltage signal value is positive, the basic voltage vector (011) is output, and when the B-phase voltage signal value is negative, the basic voltage vector (00 1); if the A phase voltage signal value exceeds -1 (<-1), the B phase voltage signal value exceeds 1 (>1), when the C phase voltage signal value is positive, the basic voltage vector (011) is output, and when the C phase voltage signal value is negative, the basic voltage vector (010) is output; if the B phase voltage signal value exceeds 1 (>1), the C phase voltage signal value exceeds -1 (<-1), when the A phase voltage signal value is positive, the basic voltage vector (110) is output, and when the A phase voltage signal value is negative, the basic voltage vector (010) is output; if the B phase voltage signal value exceeds -1 (<-1), the C phase voltage signal value exceeds 1 (>1), when the A phase voltage signal value is positive, the basic voltage vector (101) is output, and when the C phase voltage signal value is negative, the basic voltage vector (001) is output.

[0079] It can be understood that since the sum of the wave vectors of the voltage signals of phases A, B, and C is 0, there will not be a situation where all three phases exceed ±1, nor will there be a situation where only two phases exceed ±1 at the same time. Figure 4 As shown, the three-phase voltage signal wave output in this mode using the method of this embodiment can directly output a square wave according to the situation that each phase voltage signal wave exceeds ±1, which is different from the existing method that still needs modulation or calculation (i.e., transition) to a square wave.

[0080] In actual application scenarios, the polarities of the three-phase voltage signal waves are judged to dynamically determine the output basic voltage vector.

[0081] Based on the above, in the present embodiment, a linear modulation zone algorithm is implemented by injecting a zero-sequence component, and in the overmodulation zone, when located in the overmodulation zone I, the initial three-phase modulation wave is multiplied by the increment of the voltage vector hexagon relative to the maximum range of linear modulation under the voltage vector angle θ, and when located in the overmodulation zone II, the basic voltage vector is directly output according to the sector where the reference voltage vector is located, so that the voltage signal wave output in the overmodulation interval is smaller than the original harmonic, can smoothly transition to a square wave, and has a shorter running time.

[0082] Verified by simulation (see Figure 5), the overmodulation control method provided in this embodiment has fewer harmonics in the overmodulation zone I, and can smoothly transition to a square wave in the overmodulation zone II, and the gain is more linear. The purpose of reducing harmonics is to reduce conduction losses. After the 7-segment SVPWM is added, the switching loss and k value can be effectively modified under the scheme of injecting common-mode components to optimize the loss. In practical applications, the overmodulation control method provided in this embodiment basically adopts digital control and effectively saves computing resources. The traditional minimum phase error method requires inverse trigonometric functions and at least two division operations to achieve overmodulation. In this embodiment, logic control is used to implement the operation, but in the linear modulation area, the division logic will not be called.

[0083] Embodiment 2: The present invention also provides an overmodulation control module for motor control, including a memory and a processor, for executing the steps of any of the above-mentioned overmodulation control methods. In some embodiments, the processor may be a central processing unit, a controller, a microcontroller, a microprocessor, or other data processing chips. The processor is generally used to control the execution of the overmodulation control method. The overmodulation control module can be used in a motor control system, and thus can be used in conjunction with other devices / modules in the fields of vehicles.

[0084] Embodiment 3: The present invention also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the computer program implements the steps of any of the overmodulation control methods described above. The computer program may be a plurality of storage media, such as a flash memory, a hard disk, a random access memory, a static random access memory, a read-only memory, a programmable read-only memory, a magnetic memory, etc.

[0085] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0086] Through the description of the above implementation methods, technicians in this field can clearly understand that the above embodiment method can be implemented by means of software plus the necessary general hardware platform (module / chip), and of course it can also be implemented by hardware, but in many cases the former is a better implementation method.

[0087] It should be noted that the embodiments of the present invention have better practicability and do not impose any form of limitation on the present invention. Any technician familiar with the field may use the technical content disclosed above to change or modify it into an equivalent effective embodiment. However, any modification or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An overmodulation control method for motor control, characterized in that: include: Acquire the modulation ratio and the voltage vector angle to construct an initial three-phase modulation wave, wherein the initial three-phase modulation wave is a three-phase modulation wave with a modulation ratio of 1 obtained by injecting a common mode component into the carrier wave for modulation; Presetting voltage gains associated with each modulation ratio, rotating the initial three-phase modulation wave by 90° at a voltage vector angle and obtaining voltage gains associated therewith to generate a three-phase voltage signal wave; When the voltage signal values ​​of each phase in the three-phase voltage signal wave do not exceed ±1, the inverter performs modulation based on the modulation ratio; when the voltage signal wave of each phase in the three-phase voltage signal wave has and only has one phase value exceeding ±1, the inverter determines the gain of the exceeding part of the reference voltage vector according to the three-phase voltage signal wave to perform modulation; When more than one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1, the inverter outputs a basic voltage vector.

2. The overmodulation control method according to claim 1, characterized in that: The step of determining the gain of the excess portion of the reference voltage vector according to the three-phase voltage signal wave comprises: Determine in advance the gain of the excess part of the reference voltage vector corresponding to different sectors according to the voltage vector synthesis range and the maximum range of linear modulation by using the minimum phase error method; When only one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1, the sector of the voltage vector synthesis range where the reference voltage vector is located is determined, thereby determining the gain of the exceeding portion.

3. The overmodulation control method according to claim 1, characterized in that: The inverter determines the gain of the excess part of the reference voltage vector according to the three-phase voltage signal wave for modulation, including: The initial three-phase modulation wave is multiplied by the inverse of the gain of the excess portion to perform modulation.

4. The overmodulation control method according to claim 2, characterized in that: When only the A-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds 1, it is determined that the reference voltage vector is located in the second sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(π / 2-θ); when only the A-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds -1, it is determined that the reference voltage vector is located in the fifth sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(3π / 2-θ); when only the B-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds 1, it is determined that the reference voltage vector is located in the fourth sector of the voltage vector synthesis range, and the corresponding gain of the exceeding part is cos(7π / 6-θ); When only the B-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds -1, it is determined that the reference voltage vector is located in the first sector of the voltage vector synthesis range, and the gain of the corresponding excess part is cos(π / 6-θ); when only the C-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds 1, it is determined that the reference voltage vector is located in the sixth sector of the voltage vector synthesis range, and the gain of the corresponding excess part is cos(-π / 6-θ); when only the C-phase voltage signal value of each phase voltage signal wave in the three-phase voltage signal wave exceeds -1, it is determined that the reference voltage vector is located in the third sector of the voltage vector synthesis range, and the gain of the corresponding excess part is cos(5π / 6-θ).

5. The overmodulation control method according to claim 1, characterized in that: The output basic voltage vector includes: When more than one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1, and only two phase voltage signal values ​​in the three-phase voltage signal wave exceed ±1, the inverter outputs a basic voltage vector according to the polarity of each phase voltage signal value.

6. The overmodulation control method according to claim 5, characterized in that: For a three-phase voltage signal, when the voltage signal value is positive, 1 is output, and when the voltage signal value is negative, 0 is output to output a basic voltage vector.

7. The overmodulation control method according to claim 6, characterized in that: For any phase voltage signal whose value exceeds ±1, when the voltage signal value exceeds 1, 1 is output, and when the voltage signal value exceeds -1, 0 is output accordingly.

8. The overmodulation control method according to claim 1, characterized in that: When the voltage signal value of each phase in the three-phase voltage signal wave does not exceed ±1, the inverter is in the linear modulation mode; when the voltage signal wave of each phase in the three-phase voltage signal wave has only one phase value exceeding ±1, the inverter is in the modulation zone I mode; When more than one phase value of each phase voltage signal wave in the three-phase voltage signal wave exceeds ±1, the inverter is in the modulation zone II mode.

9. An overmodulation control module for motor control, characterized in that: It comprises a memory and a processor, and is used to execute the steps of the overmodulation control method described in any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the overmodulation control method described in any one of claims 1 to 8 are implemented.

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