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-phase full-bridge 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 a large sector and a medium sector according to the basic vector; judging the large sector and the medium sector based on a preset modulation reference signal, 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, the action time of the basic vector and the required modulation mode. The pulse width modulation method and device provided by the embodiment of the present invention can improve the modulation efficiency.

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] As a device for converting DC to AC, inverters are widely used in various electrical appliances and power systems. Inverters can be controlled by SVPWM (Space Vector Pulse Width Modulation) algorithm.

[0003] At present, the existing pulse width modulation method has a long modulation time, which affects the modulation efficiency. Summary of the invention

[0004] The embodiments of the present invention provide a pulse width modulation method and device to improve modulation efficiency.

[0005] 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-phase full-bridge topology structure, and the pulse width modulation method includes:

[0006] Obtaining a basic vector of the three-phase inverter;

[0007] According to the basic vectors, dividing the vector space formed by the basic vectors into a large sector and a medium sector;

[0008] Based on a preset modulation reference signal, the large sector and the medium sector are judged to determine the sector where the space voltage vector is located;

[0009] 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, the action time of the basic vector and the required modulation mode.

[0010] Optionally, dividing the vector space formed by the basic vectors into a large sector and a medium sector includes:

[0011] The vector space formed by the basic vectors is divided into a first largest sector of 0°-120°, a second largest sector of 120°-240°, and a third largest sector of 240°-0°. Each of the large sectors is divided into two middle sectors by its own angle bisector, and the sector number of each large sector and the sector number of each middle sector are determined.

[0012] Optionally, judging the large sector and the medium sector based on a preset modulation reference signal to determine the sector where the space voltage vector is located includes:

[0013] 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;

[0014] According to the normalized modulation reference signals Vα1 and Vβ1, calculated values ​​A and B are obtained, wherein A=Vα1,

[0015] 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;

[0016] 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 sizes 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.

[0017] Optionally, determining the action time of the basic vector according to the sector where the space voltage vector is located includes:

[0018] When the space voltage vector is located in the first large sector, the functional relationship of T0, T1, T2 with respect to m, n and T is determined according to the middle sector where the space voltage vector is located, and T0, T1, T2 are determined based on the functional relationship; wherein T is the switching period of the pulse width modulation signal, and T0, T1, T2 are respectively the action time of the basic vectors V0, V4, V6 in one of the switching periods.

[0019] Optionally, the determining of the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector, the action time of the basic vector and the required modulation mode includes:

[0020] When the space voltage vector is located in the first large sector, determining the flipping moment 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 and the required modulation mode;

[0021] 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.

[0022] Optionally, determining the flipping moment 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 and the required modulation mode includes:

[0023] If the required modulation mode is a five-segment mode, the flipping moments t1 and t2 of the pulse width modulation signal are determined according to the action time of the basic vector, t1=T0′*0.5, t2=t1+0.5*T1′;

[0024] If the required modulation mode is a seven-segment type, the flipping moments t1, t2 and t3 of the pulse width modulation signal are determined according to the action time of the basic vector, t1=T0′*0.25, t2=t1+0.5*T1′, t3=t1+0.5*T2′, T0′, T1′ and T2′ are the per-unit values ​​of T0, T1 and T2 respectively.

[0025] Optionally, when the space voltage vector is located in the first middle sector of the first large sector, determining the flipping moment 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:

[0026] 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 with the upper bridge arm and the lower bridge arm of each phase in the complementary state correspond to the same comparison register.

[0027] Optionally, the value of the switching function is 0 or 1, the per-unit value of the comparison register is 0 or 1 or t1 or t2 or t3, and when the per-unit value of the comparison register is t1 or t2 or t3, it indicates that the value of the switching function of the corresponding phase jumps.

[0028] Optionally, T0 is related to m and T, T1 is related to m, n and T, and T2 is related to n and T.

[0029] 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-phase full-bridge topology structure, and the pulse width modulation device includes:

[0030] A vector acquisition module, used to acquire a basic vector of the three-phase inverter;

[0031] A sector division module, used for dividing the vector space formed by the basic vector into a large sector and a medium sector according to the basic vector;

[0032] A sector determination module, used to determine the large sector and the medium sector based on a preset modulation reference signal, and determine the sector where the space voltage vector is located;

[0033] 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.

[0034] 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-phase full-bridge 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 and a medium sector according to the basic vector; judging the large sector and the medium sector based on a preset modulation reference signal to determine 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, the action time of the basic vector and the required modulation mode. 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 and the required modulation mode, 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 speeding up the modulation process and improving the modulation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a flow chart of a pulse width modulation method provided by Embodiment 1 of the present invention;

[0036] Figure 2 is a schematic diagram of a three-phase inverter provided in Embodiment 1 of the present invention;

[0037] Figure 3 is a schematic diagram of a basic vector distribution provided by Embodiment 1 of the present invention;

[0038] Figure 4 is a flow chart of a pulse width modulation method provided by Embodiment 2 of the present invention;

[0039] Figure 5 is a schematic diagram of vector space normalization provided by Embodiment 2 of the present invention;

[0040] Figure 6 is a schematic diagram of large sector determination provided by Embodiment 2 of the present invention;

[0041] Figure 7is a schematic diagram of a reference vector projection in a large sector provided by Embodiment 2 of the present invention;

[0042] Figure 8 is a schematic diagram of a mid-sector determination provided by Embodiment 2 of the present invention;

[0043] Fig. 9 is a schematic diagram of a switch function change provided by the second embodiment of the present invention;

[0044] Fig.10 is a schematic diagram of a pulse width modulation signal configuration provided by Embodiment 2 of the present invention;

[0045] Fig.11 is a structural block diagram of a pulse width modulation device provided in Embodiment 3 of the present invention;

[0046] Fig.12 It is a structural schematic diagram of an electronic device provided in Embodiment 4 of the present invention. DETAILED DESCRIPTION

[0047] 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.

[0048] Embodiment 1

[0049] Figure 1 1 is a flow chart of a pulse width modulation method provided in the first 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-phase full-bridge 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:

[0050] Step 110: Obtain a basic vector of the three-phase inverter.

[0051] 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-phase full-bridge topology structure. Each phase of the three-phase inverter includes an upper bridge arm switch tube and a lower bridge arm switch tube. The switch function Si is defined as 1 or 0. 1 means that the upper bridge arm switch tube of phase i is closed and the lower bridge arm switch tube of phase i is disconnected. 0 means that the lower bridge arm switch tube of phase i is closed and the upper bridge arm switch tube of phase i is disconnected. Phase i is phase A, phase B, and phase C of the three-phase inverter.

[0052] Step 120: Divide the vector space formed by the basic vectors into large sectors and medium sectors according to the basic vectors.

[0053] For example, Figure 3 is a 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 8 basic vectors V0-V7, including 000, 001, 011, 010, 011, 111, 101, and 100 (basic vectors 000 and 111 are zero vectors). For example, 100 means that the upper bridge arm switch tube of phase A is closed, the lower bridge arm switch tube of phase B is closed, the lower bridge arm switch tube of phase C is closed, and the other switch tubes are disconnected. 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 of which is divided into two medium sectors.

[0054] Step 130: Based on a preset modulation reference signal, a large sector and a medium sector are determined to determine the sector where the space voltage vector is located.

[0055] Specifically, firstly, the large sector where the space voltage vector is located is determined according to the size of the preset modulation reference signal, and then the middle sector of the large sector where the space voltage vector is located is determined according to the size of the preset modulation reference signal.

[0056] 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, the action time of the basic vector and the required modulation mode.

[0057] Specifically, the action time of the basic vector is determined according to the large sector and the medium sector where the space voltage vector is located, and the flipping moment and driving configuration of the PWM signal, i.e. the pulse width modulation signal, are determined according to the action time of the basic vector, the symmetry of the sector and the required modulation mode to realize SVPWM modulation.

[0058] 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 and the required modulation mode, 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 and driving configuration of the pulse width modulation signal again, thereby speeding up the modulation process and improving the modulation efficiency.

[0059] Embodiment 2

[0060] Figure 41 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-phase full-bridge 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:

[0061] Step 210: Obtain a basic vector of the three-phase inverter.

[0062] Specifically, refer to Figure 2 The three-phase inverter is a three-phase full-bridge topology structure. Each phase of the three-phase inverter includes an upper bridge arm switch tube and a lower bridge arm switch tube. The switch function Si is defined as 1 or 0. 1 means that the upper bridge arm switch tube of phase i is closed and the lower bridge arm switch tube of phase i is disconnected. 0 means that the lower bridge arm switch tube of phase i is closed and the upper bridge arm switch tube of phase i is disconnected. Phase i is phase A, phase B, and phase C of the three-phase inverter.

[0063] 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°, and each large sector is divided into two middle sectors by their respective angle bisectors, and the sector numbers of each large sector and each middle sector are determined.

[0064] Specifically, refer to Figure 2 and Figure 3 The basic vectors include 8 basic vectors V0-V7, including 000, 001, 011, 010, 011, 111, 101, and 100 (basic vectors 000 and 111 are zero vectors). For example, 001 means that the lower bridge arm switch tube P1A of phase A is closed, the lower bridge arm switch tube P2B of phase B is closed, the upper bridge arm switch tube P3A of phase C is closed, and the other switches are disconnected. 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 of which is divided into two medium sectors.

[0065] 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 vector 000-100 is located. Figure 3, each large sector includes the first medium sector and the second medium 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. The 120° area formed by the basic vectors V4 and V2 is N1=1; the 120° area formed by the basic vectors V2 and V1 is N1=2; the 120° area formed by the basic vectors V1 and V4 is N1=3.

[0066] 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 .

[0067] For example, Figure 5 Schematic diagram of vector space normalization provided by Embodiment 2 of the present invention. Figure 5 , 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 bus voltage of Udc, the hexagonal amplitude of the vector space formed by the basic vector is 2 / 3 times Udc. To facilitate subsequent calculations, the vector space is normalized and multiplied by 3 / Udc to obtain Figure 5 The regular hexagonal vector space with a side length of 2 shown in , in order to eliminate unnecessary decimals in subsequent calculations, the regular hexagonal vector space is multiplied by k / Udc for normalization, preferably, 2k / 3 is a multiple of 3, and a regular hexagonal vector space with a side length of 2k / 3 after normalization can be obtained. Exemplarily, in this embodiment, k = 3, that is, Vα1 = 3Vα, Vβ1 = 3Vβ, and a regular hexagonal vector space with a side length of 2 after normalization can be obtained. For ease of display, subsequent calculations are normalized by multiplying the regular hexagonal vector space by 3, and in other embodiments, other k values ​​can also be used for normalization.

[0068] Step 240: Obtain calculated values ​​A and B according to the normalized modulation reference signals Vα1 and Vβ1, where A=Vα1,

[0069] Step 250 , 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, determine the sector number of the large sector where the space voltage vector is located.

[0070] For example, Figure 6 FIG. 2 is a schematic diagram of a large sector determination method provided by Embodiment 2 of the present invention. Figure 6, when B > 0, if A + B > 0, then N1 = 1; if A + B ≤ 0, then N1 = 2. When B ≤ 0, if A - B > 0, then N1 = 3; if A - B ≤ 0, then N1 = 2.

[0071] 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.

[0072] Wherein, m and n are respectively the projection values of the synthesized vector Vref1 of Vα1 and Vβ1 on the 0-degree coordinate axis and the 120-degree coordinate axis in the 120-degree coordinate system. Figure 7 It is a schematic diagram of the projection of a reference vector in a large sector provided by the second embodiment of the present invention. Refer to Figure 7 , the synthesized vector Vref1 is decomposed into Vα1 and Vβ1 in the rectangular coordinate system. Vref1 can be decomposed according to the parallelogram rule in the 120-degree coordinate system to obtain the projection values m and n. Therefore, by projecting Vα1 and Vβ1 respectively according to the parallelogram rule, the relationship between them and m and n, that is, the preset equation of A and / or B, can be obtained. The preset equation of A and / or B includes: 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. According to the geometric relationship, when m is greater than 2, overmodulation will occur. Therefore, when m is greater than 2, set m = 2, n = 2n / m. Exemplarily, Figure 8 It is a schematic diagram of middle sector determination provided by 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.

[0073] Step 270: When the space voltage vector is located in the first large sector, determine the functional relationship of T0, T1, and T2 with respect to m, n, and T according to the middle sector where the space voltage vector is located, and determine T0, T1, and T2 based on the functional relationship.

[0074] Wherein, T is the switching period of the pulse width modulation signal, and T0, T1, and T2 are the action time of the basic vectors V0 / V7, V4, and V6 in one switching period, respectively. T0 is related to m and T, T1 is related to m, n, and T, and T2 is related to n and T. For example, the functional relationship of T0, T1, and T2 with respect to m, n, and T includes: taking N1=1 and N2=1 as an example, mT=2T1+2T2, nT=2T2, and T=T0+T1+T2, and it can be obtained that T0=(2-m)*T / 2, T1=(mn)*T / 2, and T2=n*T / 2. Wherein, mT=2T1+2T2 is obtained by using the volt-second balance principle on the reference vector and the two basic vectors on the 0-degree axis, nT=2T2 is obtained by using the volt-second balance principle on the reference vector and the two basic vectors on the 120-degree axis, and T=T0+T1+T2 is a time constraint relationship. In order to facilitate subsequent calculations, T0, T1, and T2 are normalized by dividing them by T / 2 to eliminate the influence of the switching period T and simplify the operation, so that the time after normalization is: T0′=2-m, T1′=mn, T2′=n.

[0075] Step 280, when the space voltage vector is located in the first large sector, determining the flipping moment 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 and the required modulation mode, specifically includes:

[0076] If the required modulation mode is a five-segment mode, the flipping moments t1 and t2 of the pulse width modulation signal are determined according to the action time of the basic vector, t1 = T0′*0.5, t2 = t1+0.5*T1′;

[0077] If the required modulation mode is a seven-segment type, the flipping moments t1, t2 and t3 of the pulse width modulation signal are determined according to the action time of the basic vector, t1=T0′*0.25, t2=t1+0.5*T1′, t3=t1+0.5*T2′, T0′, T1′ and T2′ are the per-unit values ​​of T0, T1 and T2 respectively.

[0078] Furthermore, 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. Among them, the value of the switching function is 0 or 1, the per-unit value of the comparison register is 0 or 1 or t1 or t2 or t3, and when the per-unit value of the comparison register is t1 or t2 or t3, it means that the value of the switching function of the corresponding phase jumps.

[0079] Specifically, according to the principle that only one phase can have a switching function jump at the same time, the calling process of the basic vectors in the seven-segment modulation mode and the five-segment modulation mode in one switching cycle is shown in Table 1. The changing order of the basic vectors changes according to the size of the sequence numbers in Table 1.

[0080] Table 1 Basic vector change order

[0081] Modulation Mode No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 No.7 Seven-segment modulation V0(000) V4(100) V6(110) V7(111) V6(110) V4(100) V0(000) Five-band modulation V0(000) V4(100) V6(110) V4(100) V0(000) / /

[0082] 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 first phase transition of the switching state is t1, the second phase transition is t2, and the last phase transition is t3, according to Figure 8 As shown in the schematic diagram of the switching function change, if the seven-segment modulation mode is used, t1 = T0'*0.25, t2 = t1+0.5*T1', t3 = t1+0.5*T2' can be obtained. If the five-segment modulation mode is used, t1 = T0'*0.5, t2 = t1+0.5*T1' can be obtained. 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.10 As shown. The drive signal EPWM1 ​​controls P1A and P1B of the A-phase bridge arm, the drive signal EPWM2 controls P2A and P2B of the B-phase bridge arm, and the drive signal EPWM3 controls P3A and P3B 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) is Compx (x=1 / 2 / 3). According to the PWM signal configuration method, the corresponding relationship between the switch function and the comparison register value is shown in Table 2 below.

[0083] Table 2 Correspondence between switch function and compare register value

[0084] Switch Function Comp1 / 2 / 3 0 1 1 0

[0085] Specifically, according to the change process of the switching function in Table 1 and the order of the change phases, when the seven-segment modulation mode is adopted, Comp1=t1, Comp2=t2, Comp3=t3 can be obtained; when the five-segment modulation mode is adopted, Comp1=t1, Comp2=t2, Comp3=1 can be obtained.

[0086] Step 290, based on the symmetry of the sectors, 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, 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.

[0087] The drive configuration includes the configuration of the values ​​of the comparison registers of the pulse width modulation signal. Specifically, the modulation result in the above step 280 is the modulation result when N1=1 and N2=1. When N2=2, the results of phase A and phase B are swapped according to symmetry, as shown in the following formula:

[0088] Temp1 = Comp1;

[0089] Comp1 = Comp2;

[0090] Comp2 = Temp1;

[0091] When N1=2, according to the rotational symmetry, the result of phase C is given to phase A, the result of phase B is given to phase C, and the result of phase A is given to phase B, and the replacement is performed as follows:

[0092] Temp1 = Comp1;

[0093] Comp1 = Comp3;

[0094] Comp3 = Comp2;

[0095] Comp2 = Temp1;

[0096] When N1=3, according to the rotational symmetry, the result of phase B is given to phase A, the result of phase C is given to phase B, and the result of phase A is given to phase C, and the replacement is performed as follows:

[0097] Temp1 = Comp1;

[0098] Comp1 = Comp2;

[0099] Comp2 = Comp3;

[0100] Comp3 = Temp1;

[0101] Assuming that the period register value is p, the final PWM module comparison register value is:

[0102] Compare1=Comp1*p

[0103] Compare2=Comp2*p

[0104] Compare3=Comp3*p

[0105] The pulse width modulation method provided in this embodiment determines the large sector where the space voltage vector is located according to the calculated values ​​A and B obtained by the modulation reference signals Vα and Vβ, and then determines the middle 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 Vα and Vβ 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 driving configuration of the PWM signal according to the action time of the basic vector and the required modulation mode. 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 driving configuration of the PWM signal do not need to be calculated again, but only need to be replaced, thereby speeding up the modulation process and improving the modulation efficiency; and the combination of the seven-segment and five-segment modulation modes facilitates switching in practical applications.

[0106] Embodiment 3

[0107] Fig.11 1 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, and the three-phase inverter is a three-phase full-bridge topology structure. Fig.11 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. 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 a large sector and a medium sector according to the basic vector; the sector determination module 330 is used to determine the large sector and the medium sector based on a preset modulation reference signal, 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, the action time of the basic vector and the required modulation mode.

[0108] Based on the above implementation, the sector division module is specifically used to 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 the sector numbers of each large sector and each middle sector are determined.

[0109] In one implementation, the sector determination module 330 includes:

[0110] 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;

[0111] 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,

[0112] 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 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;

[0113] A middle sector determination unit is used to represent m and n based on the sector number of the large sector where the space voltage vector is located, using preset equations of A and / or B, and determine the sector number of the middle sector where the space voltage vector is located according to the sizes 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.

[0114] Optionally, the signal modulation module 340 is specifically used to determine the functional relationship of T0, T1, T2 with respect to m, n and T according to the middle sector where the space voltage vector is located when the space voltage vector is located in the first large sector, and determine T0, T1, T2 based on the functional relationship; wherein T is the switching period of the pulse width modulation signal, and T0, T1, T2 are respectively the action time of the basic vectors V0, V4, V6 in one switching period.

[0115] Optionally, the signal modulation module 340 includes:

[0116] A first modulation unit, used for determining the flipping moment 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 and the required modulation mode when the space voltage vector is located in the first large sector;

[0117] 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.

[0118] Optionally, the first modulation unit includes:

[0119] The first modulation subunit is used for determining the flipping time t1 and t2 of the pulse width modulation signal according to the action time of the basic vector if the required modulation mode is a five-segment mode, t1=T0′*0.5, t2=t1+0.5*T1′;

[0120] The second modulation subunit is used to determine the flipping moments t1, t2 and t3 of the pulse width modulation signal according to the action time of the basic vector if the required modulation mode is a seven-segment mode. t1=T0′*0.25, t2=t1+0.5*T1′, t3=t1+0.5*T2′, and T0′, T1′ and T2′ are the per-unit values ​​of T0, T1 and T2 respectively.

[0121] Optionally, the first modulation unit is specifically used to determine the correspondence between the switching functions of each phase of the three-phase inverter and the scalar 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 switching tubes of each phase of the three-phase inverter when the spatial 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 switching tube of each phase, and the switching tube with the upper bridge arm and lower bridge arm of each phase in a complementary state corresponds to the same comparison register.

[0122] 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.

[0123] Embodiment 4

[0124] 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.

[0125] 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).

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.12 As 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.

[0131] 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, and the three-phase inverter is a three-phase full-bridge topology structure. The pulse width modulation method includes:

[0132] Get the basic vector of the three-phase inverter;

[0133] According to the basic vectors, the vector space formed by the basic vectors is divided into a large sector and a medium sector;

[0134] Based on a preset modulation reference signal, a large sector and a medium sector are judged to determine the sector where the space voltage vector is located;

[0135] According to the sector where the space voltage vector is located, the action time of the basic vector is determined, so as to determine the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector, the action time of the basic vector and the required modulation mode.

[0136] Embodiment 5

[0137] 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-phase full-bridge topology structure. The pulse width modulation method includes:

[0138] Get the basic vector of the three-phase inverter;

[0139] According to the basic vectors, the vector space formed by the basic vectors is divided into a large sector and a medium sector;

[0140] Based on a preset modulation reference signal, a large sector and a medium sector are judged to determine the sector where the space voltage vector is located;

[0141] According to the sector where the space voltage vector is located, the action time of the basic vector is determined, so as to determine the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector, the action time of the basic vector and the required modulation mode.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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., through the Internet using an Internet service provider).

[0146] 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-phase full-bridge 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 and a medium sector; Based on a preset modulation reference signal, the large sector and the medium 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, the action time of the basic vector and the required modulation mode.

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 and a medium sector comprises: The vector space formed by the basic vectors is divided into a first largest sector of 0°-120°, a second largest sector of 120°-240°, and a third largest sector of 240°-0°. Each of the large sectors is divided into two middle sectors by its own angle bisector, and the sector number of each large sector and the sector number of each middle sector are determined.

3. The pulse width modulation method according to claim 2, characterized in that: The step of judging the large sector and the medium sector based on the preset modulation reference signal to determine the sector where the space voltage vector is located includes: 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 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 sizes 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.

4. The pulse width modulation method according to claim 3, characterized in that: 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 large sector, the functional relationship of T0, T1, T2 with respect to m, n and T is determined according to the middle sector where the space voltage vector is located, and T0, T1, T2 are determined based on the functional relationship; wherein T is the switching period of the pulse width modulation signal, and T0, T1, T2 are respectively the action time of the basic vectors V0, V4, V6 in one of the switching periods.

5. The pulse width modulation method according to claim 4, characterized in that: The determining of the flipping moment and driving configuration of the pulse width modulation signal based on the symmetry of the sector, the action time of the basic vector and the required modulation mode comprises: When the space voltage vector is located in the first large sector, determining the flipping moment 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 and the required modulation mode; 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: The step of determining the flipping moment 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 and the required modulation mode comprises: If the required modulation mode is a five-segment mode, the flipping moments t1 and t2 of the pulse width modulation signal are determined according to the action time of the basic vector, t1=T0′*0.5, t2=t1+0.5*T1′; If the required modulation mode is a seven-segment type, the flipping moments t1, t2 and t3 of the pulse width modulation signal are determined according to the action time of the basic vector, t1=T0′*0.25, t2=t1+0.5*T1′, t3=t1+0.5*T2′, T0′, T1′ and T2′ are the per-unit values ​​of T0, T1 and T2 respectively.

7. The pulse width modulation method according to claim 6, characterized in that: When the space voltage vector is located in the first middle sector of the first large sector, determining the flipping moment 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 with the upper bridge arm and the lower bridge arm of each phase in the complementary state correspond to the same comparison register.

8. The pulse width modulation method according to claim 7, characterized in that: The value of the switching function is 0 or 1, the per-unit value of the comparison register is 0 or 1 or t1 or t2 or t3, and when the per-unit value of the comparison register is t1 or t2 or t3, it indicates that the value of the switching function of the corresponding phase jumps.

9. The pulse width modulation method according to claim 4, characterized in that: T0 is related to m and T, T1 is related to m, n and T, and T2 is related to n and T.

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-phase full-bridge 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 vector into a large sector and a medium sector according to the basic vector; A sector determination module, used to determine the large sector and the medium 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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