A pulse width modulation method and device

Abstract

The embodiment of the present invention discloses a pulse width modulation method and device. The pulse width modulation method is applied to a three-phase inverter, and the three-phase inverter is a three-level topology structure. The pulse width modulation method includes: obtaining the basic vector of the three-phase inverter; dividing the vector space formed by the basic vector into large sectors, medium sectors and small sectors according to the basic vector; judging the large sectors, medium sectors and small sectors based on the preset modulation reference signal and the symmetry of the sectors, and determining the sectors where the space voltage vectors are located; determining the action time of the basic vector according to the sectors where the space voltage vectors are located, so as to determine the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sectors and the action time of the basic vectors. The pulse width modulation method and device provided by the embodiment of the present invention can solve the problems of large amount of calculation and complex calculation in the pulse width modulation process.

Description

Technical Field

[0001] The embodiments of the present invention relate to pulse width modulation technology, and more particularly to a pulse width modulation method and device. Background Art

[0002] For devices that require pulse width modulation, such as inverters, the size and cost of the inverter can be reduced by increasing its switching frequency. Usually, the switching cycle of the inverter is used as the execution cycle of related interrupt programs such as inverter sampling and loop control. The increase in the switching frequency of the inverter reduces the time it takes for the interrupt program to complete execution. Therefore, in the case of limited interrupt time resources, the execution time of the modulation part of the program is reduced to leave more interrupt time resources for the control loop part of the inverter, thereby improving the performance of the inverter. For this purpose, pulse width modulation is performed by optimizing the modulation algorithm. At present, the existing pulse width modulation methods have large amount of calculations and complex calculations in the pulse width modulation process. Summary of the invention

[0003] The embodiments of the present invention provide a pulse width modulation method and device to solve the problems of large amount of calculation and complex calculation in the pulse width modulation process.

[0004] In a first aspect, an embodiment of the present invention provides a pulse width modulation method, wherein the pulse width modulation method is applied to a three-phase inverter, wherein the three-phase inverter is a three-level topology structure, and the pulse width modulation method includes:

[0005] Obtaining a basic vector of the three-phase inverter;

[0006] According to the basic vectors, dividing the vector space formed by the basic vectors into a large sector, a medium sector and a small sector;

[0007] Based on the preset modulation reference signal and the symmetry of the sectors, the large sector, the medium sector and the small sector are judged to determine the sector where the space voltage vector is located;

[0008] The action time of the basic vector is determined according to the sector where the space voltage vector is located, so as to determine the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector and the action time of the basic vector.

[0009] Optionally, dividing the vector space formed by the basic vectors into a large sector, a medium sector and a small sector includes:

[0010] The vector space formed by the basic vectors is divided into a first large sector of 0°-120°, a second large sector of 120°-240°, and a third large sector of 240°-0°. Each of the large sectors is divided into two middle sectors by its own angle bisector, and each of the middle sectors is divided into six small sectors. The sector numbers of the large sectors, the middle sectors, and the small sectors are determined.

[0011] Optionally, judging the large sector, the medium sector, and the small sector based on a preset modulation reference signal to determine the sector where the space voltage vector is located includes:

[0012] Based on the preset modulation reference signals Vα and Vβ, the preset modulation reference signals Vα and Vβ are normalized to obtain normalized modulation reference signals Vα1 and Vβ1;

[0013] According to the normalized modulation reference signals Vα1 and Vβ1, calculated values ​​A and B are obtained, wherein A=Vα1,

[0014] Determine the sector number of the large sector where the space voltage vector is located according to the magnitude relationship between the calculated value B and 0, and the magnitude relationship between the added value and / or the subtracted value of the calculated values ​​A and B and 0;

[0015] Based on the sector number of the large sector where the space voltage vector is located, m and n are represented by preset equations of A and / or B, and the sector number of the medium sector where the space voltage vector is located is determined according to the magnitudes of m and n, where m and n are projection values ​​of the synthetic vector of Vα1 and Vβ1 on the 0 degree coordinate axis and the 120 degree coordinate axis of the 120 degree coordinate system, respectively;

[0016] Based on the sector symmetry and the large sector and the middle sector where the space voltage vector is located, the sector number of the small sector where the space voltage vector is located is determined according to the preset relationship group of m and n.

[0017] Optionally, each of the small sectors corresponds to a plurality of vector sequences formed by basic vectors V1, V2, and V3, each vector sequence includes the basic vectors V1, V2, and V3, and each vector sequence has a corresponding clamping phase and clamping state;

[0018] The step of determining the action time of the basic vector according to the sector where the space voltage vector is located includes:

[0019] When the space voltage vector is located in the first medium sector of the first large sector, T is determined according to the small sector where the space voltage vector is located and the required vector sequence. 1 , T 2 , T 3Regarding the functional relationship among m, n and T, T is determined based on the functional relationship. 1 , T 2 , T 3 ; Where T is the switching period of the pulse width modulation signal, T 1 , T 2 , T 3 are respectively the action time of the basic vectors V1, V2, V3 in one switching cycle.

[0020] Optionally, the determining of the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector and the action time of the basic vector includes:

[0021] When the space voltage vector is located in the first middle sector of the first large sector, the flipping time t1, t2 of the pulse width modulation signal and the driving configuration of the pulse width modulation signal are determined according to the action time of the basic vector; wherein t1=T 1 '*0.5, t2=t1+0.5*T 2 ′,T 1 ′ and T 2 T 1 and T 2 The per unit value of

[0022] Based on the symmetry of the sectors, the flipping moment and driving configuration of the pulse width modulation signal when the space voltage vector is located in the first middle sector of the first large sector are determined, and the flipping moment and driving configuration of the pulse width modulation signal when the space voltage vector is located in the second middle sector of the first large sector, the middle sectors of the second large sector, and the middle sectors of the third largest sector are determined.

[0023] Optionally, when the space voltage vector is located in the first middle sector of the first large sector, determining the flipping moments t1 and t2 of the pulse width modulation signal and the driving configuration of the pulse width modulation signal according to the action time of the basic vector includes:

[0024] When the space voltage vector is located in the first middle sector of the first large sector, the corresponding relationship between the switching function of each phase of the three-phase inverter and the per-unit value of the comparison register of the pulse width modulation signal is determined according to the complementary state of the upper bridge arm and the lower bridge arm switch tubes of each phase of the three-phase inverter; the value of the switching function of each phase of the three-phase inverter corresponds to the on-off state of the switch tube of each phase, and the switch tubes in which the upper bridge arm and the lower bridge arm of each phase are in a complementary state correspond to the same comparison register;

[0025] According to the corresponding relationship, the per-unit value of each comparison register corresponding to each vector sequence of each small sector is determined.

[0026] Optionally, the value of the switching function is -1 or 0 or 1, the per-unit value of the comparison register is 0 or 1 or t1 or t2, and when the per-unit value of the comparison register is t1 or t2, it indicates that the value of the switching function of the corresponding phase jumps.

[0027] Optionally, the determining the sector number of the small sector where the space voltage vector is located according to the preset relationship group of m and n based on the sector symmetry and the large sector and the medium sector where the space voltage vector is located, includes:

[0028] When the space vector is located in a first middle sector of one of the large sectors, determining the small sector where the space vector is located according to a preset relationship group of m and n;

[0029] Based on the symmetry of sectors, when the space vector is located in the second middle sector of the large sector, the values ​​of m and n are swapped, and the small sector where the space vector is located is determined according to the preset relationship group.

[0030] Optionally, each of the small sectors corresponds to two or three vector sequences, and the clamping phases of the vector sequences corresponding to the same small sector are different.

[0031] In a second aspect, an embodiment of the present invention provides a pulse width modulation device, wherein the pulse width modulation device is applied to a three-phase inverter, wherein the three-phase inverter is a three-level topology structure, and the pulse width modulation device includes:

[0032] A vector acquisition module, used to acquire a basic vector of the three-phase inverter;

[0033] A sector division module, used for dividing the vector space formed by the basic vector into a large sector, a medium sector and a small sector according to the basic vector;

[0034] A sector determination module, used to determine the large sector, the medium sector and the small sector based on a preset modulation reference signal, and determine the sector where the space voltage vector is located;

[0035] The signal modulation module is used to determine the action time of the basic vector according to the sector where the space voltage vector is located, so as to determine the flipping moment and driving configuration of the pulse width modulation signal.

[0036] The pulse width modulation method and device provided by the embodiment of the present invention are applied to a three-phase inverter, and the three-phase inverter is a three-level topology structure. The pulse width modulation method includes: obtaining a basic vector of the three-phase inverter; dividing the vector space formed by the basic vector into a large sector, a middle sector and a small sector according to the basic vector; judging the large sector, the middle sector and the small sector based on a preset modulation reference signal and the symmetry of the sector, and determining the sector where the space voltage vector is located; determining the action time of the basic vector according to the sector where the space voltage vector is located, so as to determine the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector and the action time of the basic vector. The pulse width modulation method and device provided by the embodiment of the present invention determine the sector where the space voltage vector is located by dividing and judging each sector, and determine the action time of the basic vector according to the sector where the space voltage vector is located. After determining the action time of the basic vector, according to the symmetry of the sector, when the space voltage vector is in other sectors, there is no need to perform the calculation of the action time of the basic vector and the calculation of the flipping moment of the pulse width modulation signal and the driving configuration again, thereby reducing the amount of calculation and solving the problem of large amount of calculation and complex calculation of pulse width modulation in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a flow chart of a pulse width modulation method provided by Embodiment 1 of the present invention;

[0038] Figure 2 is a schematic diagram of a three-phase inverter provided in Embodiment 1 of the present invention;

[0039] Figure 3 is a schematic diagram of a basic vector distribution provided by Embodiment 1 of the present invention;

[0040] Figure 4 is a flow chart of a pulse width modulation method provided by Embodiment 2 of the present invention;

[0041] Figure 5 is a schematic diagram of sector distribution provided by Embodiment 2 of the present invention;

[0042] Figure 6 is a schematic diagram of vector space normalization provided by Embodiment 2 of the present invention;

[0043] Figure 7 is a schematic diagram of large sector determination provided by Embodiment 2 of the present invention;

[0044] Figure 8 is a schematic diagram of a mid-sector determination provided by Embodiment 2 of the present invention;

[0045] Fig. 9 is a schematic diagram of a switch function change provided by the second embodiment of the present invention;

[0046] Fig.10 is a schematic diagram of a pulse width modulation signal configuration provided by Embodiment 2 of the present invention;

[0047] Fig.11 is a structural block diagram of a pulse width modulation device provided in Embodiment 3 of the present invention;

[0048] Fig.12 It is a structural schematic diagram of an electronic device provided in Embodiment 4 of the present invention. DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0050] Embodiment 1

[0051] Figure 1 1 is a flow chart of a pulse width modulation method provided in Embodiment 1 of the present invention. This embodiment can be applied to aspects such as pulse width modulation of a three-phase inverter. The three-phase inverter is a three-level topology structure. The method can be executed by a pulse width modulation device. The device can be integrated in an electronic device such as a computer. The device can be implemented in the form of software and / or hardware. The method specifically includes the following steps:

[0052] Step 110: Obtain a basic vector of the three-phase inverter.

[0053] For example, Figure 2 Schematic diagram of a three-phase inverter provided by Embodiment 1 of the present invention. Figure 2 The three-phase inverter is a three-level topology structure. Each phase of the three-phase inverter has two upper bridge arms and two lower bridge arms. The switch function Si is defined as 1, 0 or -1. 1 means that the upper two power tubes of the i-phase bridge arm are closed and the remaining power tubes of the i-phase are disconnected. 0 means that the middle two power tubes of the i-phase bridge arm are closed and the remaining power tubes of the i-phase are disconnected. -1 means that the lower two power tubes of the i-phase bridge arm are closed and the remaining power tubes of the i-phase are disconnected. The i-phase is the A-phase, B-phase and C-phase of the three-phase inverter.

[0054] Step 120: According to the basic vectors, the vector space formed by the basic vectors is divided into a large sector, a medium sector and a small sector.

[0055] For example, Figure 3 Schematic diagram of a basic vector distribution provided by the first embodiment of the present invention. Figure 2 and Figure 3, the basic vectors include 000, 001, 011, 111, 101, 100, 10-1, -10-1, etc., a total of 27 basic vectors (basic vectors 000, 111, -1-1-1 are zero vectors). For example, 10-1 means that the upper two power tubes of the A-phase bridge arm are closed, the middle two power tubes of the B-phase bridge arm are closed, and the lower two power tubes of the C-phase bridge arm are closed. The vector space formed by the basic vectors can be divided into multiple large sectors, such as Figure 3 The three red lines divide the vector space into three large sectors, each large sector is divided into two medium sectors, and each medium sector is divided into multiple small sectors.

[0056] Step 130: Based on the preset modulation reference signal and the symmetry of the sectors, a large sector, a medium sector and a small sector are determined to determine the sector where the space voltage vector is located.

[0057] Specifically, firstly, according to the size of the preset modulation reference signal, the large sector where the space voltage vector is located is determined, then the middle sector where the space voltage vector is located is determined, and finally the small sector where the space voltage vector is located is determined. When the space vector is located in the first middle sector of the first large sector, according to the size of the preset modulation reference signal, the small sector where the space vector is located is determined, and based on the symmetry of the sectors, according to the size of the preset modulation reference signal, the small sector where the space vector is located when it is located in the second middle sector of the first large sector is determined.

[0058] Step 140: Determine the action time of the basic vector according to the sector where the space voltage vector is located, so as to determine the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector and the action time of the basic vector.

[0059] Specifically, according to the large sector, medium sector and small sector where the space voltage vector is located, the action time of the basic vector is determined, and according to the action time of the basic vector and the symmetry of the sector, the flipping moment and driving configuration of the PWM (Pulse Width Modulation) signal, i.e., the pulse width modulation signal, are determined to realize DSVPWM (Discontinuous Space Vector Pulse Width Modulation).

[0060] It should be noted that the specific duration of the above preset time can be determined according to actual control requirements and is not limited here.

[0061] The pulse width modulation method provided in this embodiment includes: obtaining a basic vector of a three-phase inverter; dividing the vector space formed by the basic vector into a large sector, a middle sector and a small sector according to the basic vector; judging the large sector, the middle sector and the small sector based on a preset modulation reference signal and the symmetry of the sector, and determining the sector where the space voltage vector is located; determining the action time of the basic vector according to the sector where the space voltage vector is located, so as to determine the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector and the action time of the basic vector. The pulse width modulation method provided in this embodiment determines the sector where the space voltage vector is located by dividing and judging each sector, and determines the action time of the basic vector according to the sector where the space voltage vector is located. After determining the action time of the basic vector, according to the symmetry of the sector, when the space voltage vector is in other sectors, it is not necessary to perform the action time calculation of the basic vector and the flipping moment and driving configuration calculation of the pulse width modulation signal again, thereby reducing the amount of calculation, and solving the problem of large amount of calculation and complex calculation of pulse width modulation in the prior art.

[0062] Embodiment 2

[0063] Figure 4 1 is a flow chart of a pulse width modulation method provided in the second embodiment of the present invention. This embodiment can be applied to aspects such as pulse width modulation of a three-phase inverter. The three-phase inverter is a three-level topology structure. The method can be executed by a pulse width modulation device. The device can be integrated in an electronic device such as a computer. The device can be implemented in the form of software and / or hardware. The method specifically includes the following steps:

[0064] Step 210: Obtain a basic vector of the three-phase inverter.

[0065] The basic vector of the three-phase inverter can refer to the specific description of the above step 110, which will not be repeated here.

[0066] Step 220, divide the vector space formed by the basic vectors into the first largest sector of 0°-120°, the second largest sector of 120°-240°, and the third largest sector of 240°-0°. Each large sector is divided into two middle sectors by their respective angle bisectors, and each middle sector is divided into six small sectors. The sector numbers of each large sector, each middle sector, and each small sector are determined.

[0067] For example, Figure 5 Schematic diagram of a sector distribution provided by Embodiment 2 of the present invention. In this embodiment, the vector space formed by the basic vectors is divided into the first largest sector of 0°-120°, the second largest sector of 120°-240°, and the third largest sector of 240°-0° in a counterclockwise direction, starting from the sector line where the basic vectors 000-111 are located. Figure 5, each large sector includes the first medium sector and the second medium sector, and each medium sector includes six small sectors from the first small sector to the sixth small sector. Large sectors N1=1, 2, 3, N1=1 represents the first large sector, N1=2 represents the second large sector, and N1=3 represents the third large sector. Medium sectors N2=1, 2, N2=1 represents the first medium sector, and N2=2 represents the second medium sector. Small sectors N3=1, 2, 3, 4, 5, 6, N3=1 represents the first small sector, ..., N3=6 represents the sixth small sector.

[0068] Step 230 : Based on the preset modulation reference signals Vα and Vβ, the preset modulation reference signals Vα and Vβ are normalized to obtain normalized modulation reference signals Vα1 and Vβ1 .

[0069] For example, Figure 6 Schematic diagram of vector space normalization provided by Embodiment 2 of the present invention. Figure 6 , the synthetic vector of the preset modulation reference signals Vα and Vβ is Vref, and the synthetic vector of the normalized modulation reference signals Vα1 and Vβ1 is Vref1. For a three-phase inverter with a DC voltage of Vdc, the hexagonal amplitude of the vector space formed by the basic vector is 2 / 3 of Vdc. The space vector modulation algorithm process is independent of the DC voltage. Normalizing the vector space and dividing it by Vdc gives: Figure 6 The regular hexagonal vector space with a side length of 2 / 3 is shown in . In order to simplify subsequent calculations and avoid decimal calculations, the regular hexagonal vector space is multiplied by k for normalization. Preferably, 2k / 3 is an integer, and a regular hexagonal vector space with a side length of 2k / 3 after normalization can be obtained. Exemplarily, in this embodiment, k = 6, that is, Vα1 = 6Vα, Vβ1 = 6Vβ, and a regular hexagonal vector space with a side length of 4 after normalization can be obtained. For ease of display, subsequent calculations are normalized by multiplying the regular hexagonal vector space by 6. In other embodiments, other k values ​​can also be used for normalization.

[0070] Step 240: Obtain calculated values ​​A and B according to the normalized modulation reference signals Vα1 and Vβ1, where A=Vα1,

[0071] Step 250: Determine the sector number of the large sector where the space voltage vector is located according to the magnitude relationship between B and 0 and the magnitude relationship between the addition value and / or subtraction value of A and B and 0.

[0072] For example, Figure 7 FIG. 2 is a schematic diagram of a large sector determination method provided by Embodiment 2 of the present invention. Figure 7 When B>0, if A+B>0, then N1=1, if A+B≤0, then N1=2, when B≤0, if AB>0, then N1=3, if AB≤0, then N1=2.

[0073] Step 260: Based on the sector number of the large sector where the space voltage vector is located, represent m and n using a preset equation of A and / or B, and determine the sector number of the middle sector where the space voltage vector is located according to the magnitudes of m and n.

[0074] Among them, the first middle sector is farther from the second large sector than the second middle sector. m and n are the projection values of the synthesis vector of Vα1 and Vβ1 on the 0-degree coordinate axis and the 120-degree coordinate axis in the 120-degree coordinate system respectively. The preset equations of A and / or B include: when the space voltage vector is located in the first large sector, m = A + B, n = 2 * B; when the space voltage vector is located in the second large sector, m = -A + B, n = -A - B; when the space voltage vector is located in the third large sector, m = -2 * B, n = A - B. When m or n is greater than 4, set m = 4 and n = 4n / m. Exemplarily, Figure 8 is a schematic diagram of middle sector determination provided in the second embodiment of the present invention. Refer to Figure 8 , when N1 = 1, if m ≥ n, then N2 = 1; if m < n, then N2 = 2.

[0075] Step 270: Based on sector symmetry and the large sector and middle sector where the space voltage vector is located, determine the sector number of the small sector where the space voltage vector is located according to a preset relationship group of m and n, specifically including:

[0076] When the space vector is located in the first middle sector of one of the large sectors, determine the small sector where the space vector is located according to the preset relationship group of m and n;

[0077] Based on sector symmetry, when the space vector is located in the second middle sector of this large sector, swap the assignment of m and n, and determine the small sector where the space vector is located according to the preset relationship group.

[0078] Specifically, the preset relationship group of m and n includes: when the space voltage vector is located in the first middle sector of the first large sector, if 2n ≤ m < 2 and n ≥ 0, it is determined that the space voltage vector is located in the first small sector; if m < 2 and 2n ≤ m < 2n, it is determined that the space voltage vector is located in the second small sector; if n ≥ 0 and n + 2 < m ≤ 4, it is determined that the space voltage vector is located in the third small sector; if m ≥ 2 and 2n ≤ m ≤ n + 2, it is determined that the space voltage vector is located in the fourth small sector; if n ≤ 2 and 2 ≤ m ≤ 2n, it is determined that the space voltage vector is located in the fifth small sector; if n > 2 and n ≤ m < 4, it is determined that the space voltage vector is located in the sixth small sector.

[0079] Specifically, Table 1 shows the conditions for determining the small sector where the space voltage vector is located and the corresponding small sector when the space voltage vector is located in the first medium sector of the first large sector. As shown in Table 1, the size relationship between m and n is different, and the value of the small sector N3 is different, that is, the small sector where the space voltage vector is located is different.

[0080] Table 1N3 Determination

[0081]

[0082]

[0083] Moreover, when N1=1, N2=1 and N2=2 are symmetrical about the 60-degree axis. Therefore, when N2=2, it is only necessary to swap the values ​​of m and n of N2=1 and then make the small sector N3 determination. It can be understood that the preset relationship group of m and n remains unchanged at this time, but the original values ​​of m and n are swapped. Further, the space voltage vector is synthesized according to the basic vector of the small sector in which it is located, and only the switching state of a certain phase can be changed at a time. When the space voltage vector is in the sector of N1=1 and N2=1, the basic vector combination shown in Table 2 can be obtained.

[0084] Table 2 The small sector where the DSV pulse width modulation space vector is located and the basic vector used

[0085]

[0086] Among them, each small sector corresponds to two or three vector sequences formed by basic vectors V1, V2, and V3, each vector sequence includes the basic vectors V1, V2, and V3, each vector sequence has its own corresponding clamping phase and clamping state, and the clamping phases of each vector sequence corresponding to the same small sector are different. In addition, in different small sectors, different DSVPWM schemes can be obtained by combining the vector sequence numbers in Table 2, and the usually selected scheme is shown in Table 3.

[0087] Table 3 Common DSVPWM space vector serial number schemes

[0088] plan DPWMx N3＝1 N3＝2 N3＝3 N3＝4 N3＝5 N3＝6 0 DPWM0 3 3 1 1 1 1 1 DPWM1 1 3 2 3 1 1 2 DPWM2 1 1 2 3 3 2 3 DPWM3 3 1 1 1 3 2 4 DPWMA 2 2 2 2 2 1 5 DPWMB 1 3 1 1 3 2

[0089] Step 280: When the space voltage vector is located in the first medium sector of the first large sector, determine T according to the small sector where the space voltage vector is located and the required vector sequence. 1 , T 2 , T 3 Regarding the functional relationship between m, n and T, T is determined based on the functional relationship 1 , T 2 , T 3 .

[0090] Where T is the switching period of the PWM signal, T 1 , T 2 , T 3 are the action time of the basic vectors V1, V2, and V3 in one switching cycle. For example, the functional relationship of T1, T2, and T3 with respect to m, n, and T includes: when the space voltage vector is located in the first small sector or the second small sector, the vector sequence includes three vector sequences of vector sequence numbers 1, 2, and 3 corresponding to N3=1 / 2 as shown in Table 2, corresponding to mT=2T respectively. 1 +2T 2 , nT=2T 2 , T=T 1 +T 2 +T 3 ; mT = 2T 1 +2T 3 , nT=2T 1 , T=T 1 +T 2 +T 3 ; mT = 2T 2 +2T 3 , nT=2T 3 , T=T 1 +T 2 +T 3 When the space voltage vector is located in the first middle sector of the first large sector, if the space voltage vector is located in the third small sector, the required vector sequence is the vector sequence corresponding to the vector sequence number 1, then mT=2T is determined. 1 +4T 2 +4T 3 , nT=2T 3 , T=T 1 +T 2 +T 3 , the required vector sequence is the vector sequence corresponding to vector sequence number 2, then mT=4T 1 +4T 2 +2T 3 , nT=2T 2 , T=T 1 +T 2 +T 3 ; Where T is the switching period of the PWM signal, T 1 , T 2 , T 3 are the action time of the basic vectors V1, V2, and V3 in one switching cycle. When the space voltage vector is located in the first middle sector of the first large sector, if the space voltage vector is located in the fourth small sector or the fifth small sector, the required vector sequence is the vector sequence corresponding to the vector sequence number 1, then mT=2T is determined. 1 +4T 2 +2T3 , nT=2T 1 +2T 2 , T=T 1 +T 2 +T 3 , the required vector sequence is the vector sequence corresponding to vector sequence number 2, then mT=2T 1 +4T 2 +4T 3 , nT=2T 1 +2T 2 +4T 3 , T=T 1 +T 2 +T 3 , the required vector sequence is the vector sequence corresponding to vector sequence number 3, then mT=4T 1 +2T 2 +2T 3 , nT=2T 1 +2T 3 , T=T 1 +T 2 +T 3 When the space voltage vector is located in the first middle sector of the first large sector, if the space voltage vector is located in the sixth small sector, the required vector sequence is the vector sequence corresponding to the vector sequence number 1, then mT=2T is determined. 1 +4T 2 +4T 3 , nT=2T 1 +2T 2 +4T 3 , T=T 1 +T 2 +T 3 , the required vector sequence is the vector sequence corresponding to vector sequence number 2, then mT=2T 1 +4T 2 +2T 3 , nT=2T 1 +4T 2 +2T 3 , T=T 1 +T 2 +T 3 Among them, T is known, T 1 , T 2 , T 3 The size of is positively correlated with T. Table 4 shows the T 1 , T 2 , T 3 The solution result and the per-unit value of the solution result.

[0091] Table 4 Time solution results

[0092]

[0093]

[0094] Among them, Table 4 normalizes the basic vector action time to be solved by dividing it by T / 2, which simplifies the calculation and eliminates the influence of the switching cycle variable on the algorithm.

[0095] Step 290, when the space voltage vector is located in the first middle sector of the first large sector, determining the flipping time t1, t2 of the pulse width modulation signal and the driving configuration of the pulse width modulation signal according to the action time of the basic vector, specifically includes:

[0096] When the space voltage vector is located in the first middle sector of the first large sector, the corresponding relationship between the switching function of each phase of the three-phase inverter and the per-unit value of the comparison register of the pulse width modulation signal is determined according to the complementary state of the upper bridge arm and the lower bridge arm switch tubes of each phase of the three-phase inverter; the value of the switching function of each phase of the three-phase inverter corresponds to the on-off state of the switch tube of each phase, and the switch tubes in which the upper bridge arm and the lower bridge arm of each phase are in the complementary state correspond to the same comparison register;

[0097] According to the corresponding relationship, the per-unit value of each comparison register corresponding to each vector sequence of each small sector is determined.

[0098] Where t1 = T 1 '*0.5, t2=t1+0.5*T 2 ′,T 1 ′ and T 2 T 1 and T 2 . For example, Fig. 9 Schematic diagram of a switch function change provided by the second embodiment of the present invention. Fig. 9 , the PWM signal is symmetrically distributed within the switching cycle. If the non-clamped phase 1 switching time that occurs first is t1, and the non-clamped phase 2 switching time that occurs later is t2, according to Fig. 9 The switching function change diagram shown in the figure shows that t1 = T 1 '*0.5, t2=t1+0.5*T 2 ′. Fig.10 is a schematic diagram of a pulse width modulation signal configuration provided by the second embodiment of the present invention, with reference to Fig.10 , PWM signal configuration adopts up and down calculation mode, the action mode is as follows Fig.10As shown. The drive signal EPWMx (x = 1 / 2 / 3 / 4 / 5 / 6) controls PxA and PxB, such as the drive signal EPWM1 ​​controls P1A and P1B of the A-phase bridge arm, the drive signal EPWM2 controls P2A and P2B of the A-phase bridge arm, the drive signal EPWM3 controls P3A and P3B of the B-phase bridge arm, the drive signal EPWM4 controls P4A and P4B of the B-phase bridge arm, the drive signal EPWM5 controls P5A and P5B of the C-phase bridge arm, and the drive signal EPWM6 controls P6A and P6B ​​of the C-phase bridge arm. Fig.10 The value of the period register is normalized to 1, and the value of the comparison register corresponding to EPWMx (x = 1 / 2 / 3 / 4 / 5 / 6) is Compx (x = 1 / 2 / 3 / 4 / 5 / 6). According to the PWM signal configuration method, the corresponding relationship between the switch function and the comparison register value is shown in Table 5 below.

[0099] Table 5 Correspondence between switch function and compare register value

[0100] Switch Function Comp1 / 3 / 5 Comp2 / 4 / 6 -1 1 1 0 1 0 1 0 0

[0101] According to the change process of the switching function in Table 2, the clamped phase can be set according to Table 5. For the non-clamped phase 1 that jumps first, when the switching function jumps from -1 to 0, Comp1 / 3 / 5 is fixed to 1, and Comp2 / 4 / 6 is set to t1; when the switching function jumps from 0 to 1, Comp2 / 4 / 5 is fixed to 0, and Comp1 / 3 / 5 is set to t1. For the non-clamped phase 2 that jumps later, when the switching function jumps from -1 to 0, Comp1 / 3 / 5 is fixed to 1, and Comp2 / 4 / 6 is set to t2; when the switching function jumps from 0 to 1, Comp2 / 4 / 5 is fixed to 0, and Comp1 / 3 / 5 is set to t2. The comparator register values ​​are shown in Table 6.

[0102] Table 6 Comparison register value results after normalization

[0103]

[0104] Step 291, based on the symmetry of the sectors, determine the flipping moment and driving configuration of the pulse width modulation signal when the space voltage vector is located in the second middle sector of the first large sector, each middle sector of the second largest sector, and each middle sector of the third largest sector according to the flipping moment and driving configuration of the pulse width modulation signal when the space voltage vector is located in the first middle sector of the first large sector.

[0105] The drive configuration includes the configuration of the values ​​of each comparison register of the pulse width modulation signal. Specifically, the results in Table 6 are the modulation results when N1=1 and N2=1. When N2=2, the values ​​of Comp1 and Comp2 are swapped with the values ​​of Comp3 and Comp4 according to the symmetry, as shown in the following formula:

[0106] Temp1=Comp1; Temp2=Comp2;

[0107] Comp1=Comp3; Comp2=Comp4;

[0108] Comp3=Temp1; Comp4=Temp2;

[0109] When N1=2, according to the rotational symmetry, the following formula is used for replacement:

[0110] Temp1=Comp1; Te2=Comp2;

[0111] Comp1=Comp5; Comp2=Comp6;

[0112] Comp5=Comp3; Comp6=Comp4;

[0113] Comp3=Temp1; Comp4=Temp2;

[0114] When N1=3, according to the rotational symmetry, the following formula is used for replacement:

[0115] Temp1=Comp1; Temp2=Comp2;

[0116] Comp1=Comp3; Comp2=Comp4;

[0117] Comp3=Comp5; Comp4=Comp6;

[0118] Comp5=Temp1; Comp6=Temp2;

[0119] If the period register value is p, the final compare register value Comparex (x=1 / 2 / 3 / 4 / 5 / 6) is:

[0120] Compare1=Comp1*p

[0121] Compare2=Comp2*p

[0122] Compare3=Comp3*p

[0123] Compare4=Comp4*p

[0124] Compare5=Comp5*p

[0125] Compare6=Comp6*p

[0126] Moreover, when the space voltage vector is located in the middle sectors of the second largest sector and the middle sectors of the third largest sector, the flipping timing and driving configuration of the pulse width modulation signal can refer to the specific description when N1=1, N2=1 and N1=1, N2=2 above, and will not be repeated here.

[0127] The pulse width modulation method provided in this embodiment determines the large sector where the space voltage vector is located according to the size relationship of the modulation reference signals Vα and Vβ, and then determines the medium sector and small sector where the space voltage vector is located and the action time of the basic vector according to the projection values ​​of the synthetic vector of Vα1 and Vβ1 on the 0-degree coordinate axis and the 120-degree coordinate axis of the 120-degree coordinate system, and determines the flipping moment of the PWM signal and the value of the comparison register of the PWM signal according to the action time of the basic vector. When the space voltage vector is in other sectors, according to the symmetry and rotational symmetry of the sector, the flipping moment of the PWM signal and the value of the comparison register of the PWM signal do not need to be calculated again, but only need to be replaced, thereby reducing the amount of calculation, thereby solving the problem of large amount of calculation and complex calculation of pulse width modulation in the prior art.

[0128] Embodiment 3

[0129] Fig.11 This is a block diagram of a pulse width modulation device provided in the third embodiment of the present invention. The pulse width modulation device is applied to a three-phase inverter, which is a three-level topology structure. The pulse width modulation device includes: a vector acquisition module 310, a sector division module 320, a sector determination module 330, and a signal modulation module 340; wherein the vector acquisition module 310 is used to acquire the basic vector of the three-phase inverter; the sector division module 320 is used to divide the vector space formed by the basic vector into large sectors, medium sectors and small sectors according to the basic vector; the sector determination module 330 is used to determine the large sector, medium sector and small sector based on the preset modulation reference signal and the symmetry of the sector, and determine the sector where the space voltage vector is located; the signal modulation module 340 is used to determine the action time of the basic vector according to the sector where the space voltage vector is located, so as to determine the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector and the action time of the basic vector.

[0130] In one embodiment, the sector division module 320 is specifically used to divide the vector space formed by the basic vectors into a first largest sector of 0°-120°, a second largest sector of 120°-240°, and a third largest sector of 240°-0°. Each large sector is divided into two middle sectors by their respective angle bisectors, and each middle sector is divided into six small sectors, and the sector numbers of each large sector, each middle sector, and each small sector are determined.

[0131] Based on the above implementation, the sector determination module 330 includes:

[0132] A per-unit unit, used for per-unit normalizing preset modulation reference signals Vα and Vβ based on preset modulation reference signals Vα and Vβ to obtain normalized modulation reference signals Vα1 and Vβ1;

[0133] The calculation value determination unit is used to obtain the calculation values ​​A and B according to the normalized modulation reference signals Vα1 and Vβ1, wherein A=Vα1,

[0134] A large sector determination unit, used to determine the sector number of the large sector where the space voltage vector is located according to the magnitude relationship between B and 0 and the magnitude relationship between the addition value and / or subtraction value of A and B and 0;

[0135] A middle sector determination unit, based on the sector number of the large sector where the space voltage vector is located, represents m and n using preset equations of A and / or B, and determines the sector number of the middle sector where the space voltage vector is located according to the magnitudes of m and n, wherein m and n are projection values ​​of the composite vector of Vα1 and Vβ1 on the 0 degree coordinate axis and the 120 degree coordinate axis of the 120 degree coordinate system, respectively;

[0136] The small sector determination unit is used to determine the sector number of the small sector where the space voltage vector is located according to the preset relationship group of m and n based on the sector symmetry and the large sector and the medium sector where the space voltage vector is located.

[0137] Optionally, the small sector determination unit includes a first small sector determination subunit and a second small sector determination subunit, the first small sector determination subunit being used to determine the small sector where the space vector is located according to a preset relationship group of m and n when the space vector is located in the first middle sector of one of the large sectors; the second small sector determination subunit being used to swap the values ​​of m and n based on the symmetry of the sectors, and determine the small sector where the space vector is located according to the preset relationship group when the space vector is located in the second middle sector of the large sector.

[0138] Optionally, each small sector corresponds to a plurality of vector sequences formed by basic vectors V1, V2, and V3, each vector sequence includes the basic vectors V1, V2, and V3, and each vector sequence has a corresponding clamping phase and clamping state; the signal modulation module 340 includes a first time determination unit, and the first time determination unit is used to determine T according to the small sector where the space voltage vector is located and the required vector sequence when the space voltage vector is located in the first middle sector of the first large sector. 1 , T 2 , T 3 Regarding the functional relationship among m, n and T, T is determined based on the functional relationship. 1 , T 2 , T 3 ; Where T is the switching period of the pulse width modulation signal, T 1 , T 2 , T 3 They are respectively the action time of basic vectors V1, V2, and V3 in one switching cycle.

[0139] Optionally, the signal modulation module 340 includes a first modulation unit and a second modulation unit, wherein the first modulation unit is used to determine the flipping time t1, t2 of the pulse width modulation signal and the driving configuration of the pulse width modulation signal according to the action time of the basic vector when the space voltage vector is located in the first middle sector of the first large sector; wherein t1=T 1 '*0.5, t2=t1+0.5*T 2 ′,T 1 ′ and T 2 T 1 and T 2 The second modulation unit is used to determine the flipping moment and driving configuration of the pulse width modulation signal when the space voltage vector is located in the second middle sector of the first large sector, the middle sectors of the second largest sector, and the middle sectors of the third largest sector based on the symmetry of the sectors and according to the flipping moment and driving configuration of the pulse width modulation signal when the space voltage vector is located in the first middle sector of the first large sector.

[0140] Optionally, the first modulation unit includes a relationship determination subunit and a per-unit value determination subunit. The relationship determination subunit is used to determine the corresponding relationship between the switching function of each phase of the three-phase inverter and the per-unit value of the comparison register of the pulse width modulation signal according to the complementary state of the upper bridge arm and lower bridge arm switch tubes of each phase of the three-phase inverter when the space voltage vector is located in the first middle sector of the first large sector; the value of the switching function of each phase of the three-phase inverter corresponds to the on-off state of the switch tube of each phase, and the switch tube with the upper bridge arm and lower bridge arm of each phase in the complementary state corresponds to the same comparison register; the per-unit value determination subunit is used to determine the per-unit value of each comparison register corresponding to each vector sequence of each small sector according to the corresponding relationship.

[0141] The pulse width modulation device provided in this embodiment and the pulse width modulation method provided in any embodiment of the present invention belong to the same inventive concept and have corresponding beneficial effects. For technical details not detailed in this embodiment, please refer to the pulse width modulation method provided in any embodiment of the present invention.

[0142] Embodiment 4

[0143] Fig.12 It is a structural schematic diagram of an electronic device provided in Embodiment 4 of the present invention. Fig.12 A block diagram of an exemplary electronic device 412 suitable for use in implementing embodiments of the present invention is shown. Fig.12 The electronic device 412 shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention.

[0144] like Fig.12 As shown, the electronic device 412 is in the form of a general purpose device. The components of the electronic device 412 may include, but are not limited to: one or more processors 416, a storage device 428, and a bus 418 connecting different system components (including the storage device 428 and the processor 416).

[0145] Bus 418 represents one or more of several types of bus structures, including a storage device bus or storage device controller, a peripheral bus, an accelerated graphics port, a processor or a local bus using any of a variety of bus architectures. For example, these architectures include but are not limited to Industry Subversive Alliance (ISA) bus, Micro Channel Architecture (MAC) bus, Enhanced ISA bus, Video Electronics Standards Association (VESA) local bus and Peripheral Component Interconnect (PCI) bus.

[0146] The electronic device 412 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by the electronic device 412, including volatile and non-volatile media, removable and non-removable media.

[0147] The storage device 428 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 430 and / or cache memory 432. The electronic device 412 may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, the storage system 434 may be used to read and write non-removable, non-volatile magnetic media ( Fig.12 not shown, usually called a "hard drive"). Although Fig.12 Not shown in the figure, a disk drive for reading and writing a removable non-volatile disk (e.g., a "floppy disk"), and an optical disk drive for reading and writing a removable non-volatile optical disk, such as a read-only optical disk (Compact Disc Read-Only Memory, CD-ROM), a digital video disk (Digital Video Disc-Read Only Memory, DVD-ROM) or other optical media) may be provided. In these cases, each drive may be connected to the bus 418 via one or more data medium interfaces. The storage device 428 may include at least one program product having a set (e.g., at least one) of program modules that are configured to perform the functions of the various embodiments of the present invention.

[0148] A program / utility 440 having a set (at least one) of program modules 442 may be stored, for example, in storage device 428, such program modules 442 including, but not limited to, an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment. Program modules 442 generally perform the functions and / or methods of the embodiments described herein.

[0149] The electronic device 412 may also communicate with one or more external devices 414 (e.g., a keyboard, a pointing terminal, a display 424, etc.), may also communicate with one or more terminals that enable a user to interact with the electronic device 412, and / or communicate with any terminal that enables the electronic device 412 to communicate with one or more other computing terminals (e.g., a network card, a modem, etc.). Such communication may be performed through an input / output (I / O) interface 422. Furthermore, the electronic device 412 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) through a network adapter 420. Fig.12As shown, the network adapter 420 communicates with other modules of the electronic device 412 via the bus 418. It should be understood that, although not shown in the figure, other hardware and / or software modules can be used in conjunction with the electronic device 412, including but not limited to: microcode, terminal drivers, redundant processors, external disk drive arrays, disk arrays (Redundant Arrays of Independent Disks, RAID) systems, tape drives, and data backup storage systems.

[0150] The processor 416 executes various functional applications and data processing by running the program stored in the storage device 428, for example, implementing the pulse width modulation method provided in the embodiment of the present invention. The pulse width modulation method is applied to a three-phase inverter, which is a three-level topology structure. The pulse width modulation method includes:

[0151] Get the basic vector of the three-phase inverter;

[0152] According to the basic vectors, the vector space formed by the basic vectors is divided into a large sector, a medium sector and a small sector;

[0153] Based on the preset modulation reference signal and the symmetry of the sectors, the large sector, the medium sector and the small sector are judged to determine the sector where the space voltage vector is located;

[0154] The action time of the basic vector is determined according to the sector where the space voltage vector is located, so as to determine the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector and the action time of the basic vector.

[0155] Embodiment 5

[0156] Embodiment 5 of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, a pulse width modulation method as provided in the embodiment of the present invention is implemented. The pulse width modulation method is applied to a three-phase inverter, and the three-phase inverter is a three-level topology structure. The pulse width modulation method includes:

[0157] Get the basic vector of the three-phase inverter;

[0158] According to the basic vectors, the vector space formed by the basic vectors is divided into a large sector, a medium sector and a small sector;

[0159] Based on the preset modulation reference signal and the symmetry of the sectors, the large sector, the medium sector and the small sector are judged to determine the sector where the space voltage vector is located;

[0160] The action time of the basic vector is determined according to the sector where the space voltage vector is located, so as to determine the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector and the action time of the basic vector.

[0161] The computer storage medium of the embodiment of the present invention can adopt any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this document, a computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it.

[0162] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, which carry computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0163] Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0164] Computer program code for performing the operations of the present invention may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or terminal. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0165] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, re-modulations, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A pulse width modulation method, characterized in that: The pulse width modulation method is applied to a three-phase inverter, the three-phase inverter is a three-level topology structure, and the pulse width modulation method includes: Obtaining a basic vector of the three-phase inverter; According to the basic vectors, dividing the vector space formed by the basic vectors into a large sector, a medium sector and a small sector; Based on the preset modulation reference signal and the symmetry of the sectors, the large sector, the medium sector and the small sector are judged to determine the sector where the space voltage vector is located; The action time of the basic vector is determined according to the sector where the space voltage vector is located, so as to determine the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector and the action time of the basic vector.

2. The pulse width modulation method according to claim 1, characterized in that: The step of dividing the vector space formed by the basic vectors into a large sector, a medium sector and a small sector comprises: The vector space formed by the basic vectors is divided into a first large sector of 0°-120°, a second large sector of 120°-240°, and a third large sector of 240°-0°. Each of the large sectors is divided into two middle sectors by its own angle bisector, and each of the middle sectors is divided into six small sectors. The sector numbers of the large sectors, the middle sectors, and the small sectors are determined.

3. The pulse width modulation method according to claim 2, characterized in that: The step of judging the large sector, the medium sector and the small sector based on the preset modulation reference signal and the symmetry of the sectors, and determining the sector where the space voltage vector is located, comprises: Based on the preset modulation reference signals Vα and Vβ, the preset modulation reference signals Vα and Vβ are normalized to obtain normalized modulation reference signals Vα1 and Vβ1; According to the normalized modulation reference signals Vα1 and Vβ1, calculated values ​​A and B are obtained, wherein A=Vα1 and B=Vβ1 / √3; Determine the sector number of the large sector where the space voltage vector is located according to the magnitude relationship between the calculated value B and 0, and the magnitude relationship between the added value and / or the subtracted value of the calculated values ​​A and B and 0; Based on the sector number of the large sector where the space voltage vector is located, m and n are expressed by the preset equations of A and / or B, and the sector number of the medium sector where the space voltage vector is located is determined according to the size of m and n, wherein m and n are respectively the projection values ​​of the synthetic vector of Vα1 and Vβ1 on the 0 degree coordinate axis and the 120 degree coordinate axis of the 120 degree coordinate system; Based on the sector symmetry and the large sector and the middle sector where the space voltage vector is located, the sector number of the small sector where the space voltage vector is located is determined according to the preset relationship group of m and n.

4. The pulse width modulation method according to claim 3, characterized in that: Each of the small sectors corresponds to a plurality of vector sequences formed by basic vectors V1, V2, and V3, each of the vector sequences includes the basic vectors V1, V2, and V3, and each of the vector sequences has a corresponding clamping phase and clamping state; The step of determining the action time of the basic vector according to the sector where the space voltage vector is located includes: When the space voltage vector is located in the first middle sector of the first large sector, the functional relationship of T1, T2, T3 with respect to m, n and T is determined according to the small sector where the space voltage vector is located and the required vector sequence, and T1, T2, T3 are determined based on the functional relationship; wherein T is the switching period of the pulse width modulation signal, and T1, T2, T3 are respectively the action time of the basic vectors V1, V2, V3 in one of the switching periods.

5. The pulse width modulation method according to claim 4, characterized in that: The method of determining the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector and the action time of the basic vector comprises: When the space voltage vector is located in the first middle sector of the first large sector, the flipping moments t1 and t2 of the pulse width modulation signal and the driving configuration of the pulse width modulation signal are determined according to the action time of the basic vector; wherein t1=T1′*0.5, t2=t1+0.5*T2′, T1′ and T2′ are the per-unit values ​​of T1 and T2 respectively; Based on the symmetry of the sectors, the flipping moment and driving configuration of the pulse width modulation signal when the space voltage vector is located in the first middle sector of the first large sector are determined, and the flipping moment and driving configuration of the pulse width modulation signal when the space voltage vector is located in the second middle sector of the first large sector, the middle sectors of the second large sector, and the middle sectors of the third largest sector are determined.

6. The pulse width modulation method according to claim 5, characterized in that: When the space voltage vector is located in the first middle sector of the first large sector, determining the flipping moments t1 and t2 of the pulse width modulation signal and the driving configuration of the pulse width modulation signal according to the action time of the basic vector, includes: When the space voltage vector is located in the first middle sector of the first large sector, the corresponding relationship between the switching function of each phase of the three-phase inverter and the per-unit value of the comparison register of the pulse width modulation signal is determined according to the complementary state of the upper bridge arm and the lower bridge arm switch tubes of each phase of the three-phase inverter; the value of the switching function of each phase of the three-phase inverter corresponds to the on-off state of the switch tube of each phase, and the switch tubes in which the upper bridge arm and the lower bridge arm of each phase are in a complementary state correspond to the same comparison register; According to the corresponding relationship, the per-unit values ​​of the comparison registers corresponding to the vector sequences of the small sectors are determined.

7. The pulse width modulation method according to claim 6, characterized in that: The value of the switching function is -1 or 0 or 1, the per-unit value of the comparison register is 0 or 1 or t1 or t2, and when the per-unit value of the comparison register is t1 or t2, it indicates that the value of the switching function of the corresponding phase jumps.

8. The pulse width modulation method according to claim 3, characterized in that: The determining the sector number of the small sector where the space voltage vector is located based on the sector symmetry and the large sector and the medium sector where the space voltage vector is located according to the preset relationship group of m and n includes: When the space vector is located in a first middle sector of one of the large sectors, determining the small sector where the space vector is located according to a preset relationship group of m and n; Based on the symmetry of sectors, when the space vector is located in the second middle sector of the large sector, the values ​​of m and n are swapped, and the small sector where the space vector is located is determined according to the preset relationship group.

9. The pulse width modulation method according to claim 4, characterized in that: Each of the small sectors corresponds to two or three vector sequences, and the clamping phases of the vector sequences corresponding to the same small sector are different.

10. A pulse width modulation device, characterized in that: The pulse width modulation device is applied to a three-phase inverter, the three-phase inverter is a three-level topology structure, and the pulse width modulation device includes: A vector acquisition module, used to acquire a basic vector of the three-phase inverter; A sector division module, used for dividing the vector space formed by the basic vectors into large sectors, medium sectors and small sectors according to the symmetry between the basic vectors and sectors; A sector determination module, used to determine the large sector, the medium sector and the small sector based on a preset modulation reference signal, and determine the sector where the space voltage vector is located; The signal modulation module is used to determine the action time of the basic vector according to the sector where the space voltage vector is located, so as to determine the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector and the action time of the basic vector.

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