An SVPWM modulation strategy for a single-winding five-phase bearingless permanent magnet motor

Abstract

This invention relates to an SVPWM modulation strategy for a single-winding five-phase bearingless permanent magnet motor, belonging to the field of motor control technology. It employs a scheme that determines sectors separately using the torque plane and the levitation plane, and selects voltage vectors whose volt-second product or the sum of volt-second products is zero in another plane to synthesize a given voltage vector for this plane. The invention innovatively proposes using volt-second balanced voltage vectors to separately synthesize reference voltage vectors for the two sub-planes. Compared to the matrix inversion method used in existing technologies, this avoids the occurrence of negative values ​​in the voltage vector's duration.

Description

Technical Field

[0001] This invention relates to an SVPWM modulation strategy for a single-winding five-phase bearingless permanent magnet motor, belonging to the field of motor control technology. Background Technology

[0002] Bearingless motors are a new type of high-speed motor that integrates rotation and suspension. They not only have the excellent characteristics of magnetic bearing-supported motors, such as no lubrication, no mechanical friction, high speed and high precision, and long service life, but also effectively solve the inherent defects of magnetic bearing-supported motors, such as large axial size, need for additional electromagnetic excitation coils, and large power loss. They can break through the limitations of higher speed and greater power, broaden the application range of motors, and have broad application prospects in fields such as medical pharmaceuticals, semiconductor manufacturing, and aerospace.

[0003] Bearingless motors can be divided into two categories based on the structure of their stator windings: dual-winding and single-winding. Currently, most bearingless motors use a dual-winding structure, embedding two sets of three-phase windings (torque winding and levitation winding) with a difference of one pole pair in the stator. Two inverters are used to supply power to these windings to achieve rotor rotation and levitation. In dual-winding bearingless motors, the two stator windings are independent, resulting in a relatively simple working principle and control system. However, the two windings share stator slots, increasing the difficulty of winding and insulation, leading to increased manufacturing complexity and power loss on the stator side. Furthermore, the required levitation force is greatest when the rotor is at its maximum eccentric displacement. To meet the corresponding levitation force current requirements, the levitation force winding cannot be designed to be too thin; however, during normal operation, the levitation force current density is relatively low, and the levitation force winding cannot be fully utilized. A single-winding bearingless motor has only one set of windings on the stator side. By simultaneously injecting two sets of current components (torque current and levitation force current) using a multi-phase inverter, two magnetic fields with a phase difference of 1 pole pair can be generated to control the torque and levitation force respectively, effectively solving the problems of dual-winding bearingless motors. Although single-winding bearingless motors increase the complexity of control, they have advantages such as simple structure, low loss, and low manufacturing cost, making them an inevitable trend in the development of bearingless motors.

[0004] The drive control system of a single-winding bearingless motor uses a multiphase inverter, and the modulation voltage of each phase arm of the inverter simultaneously includes both torque and suspension components. This results in higher integration and stronger coupling for the single-winding BPMSM, making it impossible to use the same pulse width modulation (SVPWM) strategy as traditional three-phase or multiphase motors. The key challenge in implementing SVPWM for a single-winding multiphase permanent magnet synchronous motor compared to the SVPWM modulation strategies of ordinary three-phase and multiphase motors lies in:

[0005] 1) Traditional three-phase motors only need to control the reference voltage vector of the synthesized plane; traditional multiphase motors only need to control the reference voltage vector required for synthesizing the fundamental wave plane, and the synthesized vector of the harmonic plane is zero; however, single-winding multiphase permanent magnet synchronous motors need to control the reference voltage vectors of two planes, the synthesized torque subplane and the suspension subplane, at the same time.

[0006] 2) The magnitudes and phases of the two reference voltage vectors required to be synthesized for the torque subplane and the suspension subplane are not clearly correlated.

[0007] The existing literature, "SVPWM Control of a Single-Winding Five-Phase Permanent Magnet Bearingless Motor," by Jiang Haibo, Huang Jin, and Kang Min, Journal of Electrical Engineering, 2011, 26(01): 34-39, proposes utilizing the multiple control degrees of freedom of a multi-phase motor. Appropriate voltage vectors are selected in both the torque subplane and the levitation subplane. After determining the sector by judging the given synthetic voltage vector in the torque plane, a matrix relationship is written using the basic voltage vector of the sector and its duration. The conduction time of each power device in the five-phase inverter is uniquely determined by solving the inverse matrix. However, since the phase and amplitude of the voltage vector in the torque subplane are not clearly correlated with those in the levitation subplane, a simple derivation shows that while this method can uniquely determine the conduction time of each bridge arm power device, it cannot guarantee that the calculated conduction time value is non-negative. Currently, there is no effective SVPWM modulation scheme to solve the above problems for single-winding multi-phase bearingless permanent magnet motor drive systems. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides an SVPWM modulation strategy for a single-winding five-phase bearingless permanent magnet motor. This strategy can simultaneously control two sets of reference voltage vectors with arbitrary amplitude and phase on the synthetic torque subplane and the suspension subplane, overcoming the technical problem of negative values ​​appearing in the voltage vector conduction time solution in existing methods. This truly achieves decoupled control of the torque plane and the suspension plane.

[0009] The technical solution of the present invention is as follows:

[0010] An SVPWM modulation strategy for a single-winding five-phase bearingless permanent magnet motor is implemented as follows:

[0011] (1) Setting of switch status and base voltage vector

[0012] Let S be the switching state signal of phase a in the five-phase bridge arm of a five-phase voltage source inverter. a The switching status signal of phase b bridge arm is S. b The switching status signal of phase C bridge arm is S. c The switching status signal of phase d bridge arm is S d The switching status signal of phase e bridge arm is S.e The value of the switch status signal is:

[0013] When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase a, S a =1; Upper arm switch is off, lower arm switch is on, S a =0;

[0014] When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase b, S b =1; Upper arm switch is off, lower arm switch is on, S b =0;

[0015] When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase c, S c =1; Upper arm switch is off, lower arm switch is on, S c =0;

[0016] When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase d, S d =1; Upper arm switch is off, lower arm switch is on, S d =0;

[0017] When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase e, S e =1; Upper arm switch is off, lower arm switch is on, S e =0;

[0018] Based on the switching states of the five-phase bridge arms of the five-phase voltage-source inverter, 32 basic voltage vectors are obtained, denoted as U0~U100~U200~U300~U400~U50~U60~U70~U80~U90~U1 ... 31 (2) Vector space decoupling transformation

[0019] Using a constant amplitude coordinate transformation matrix T, the 32 basic voltage vectors of the five-phase inverter are projected onto two mutually orthogonal sub-planes, α1-β1 and α2-β2, respectively. All voltage vectors are based on the DC bus voltage V. dc Per-unit voltage is used as a reference voltage;

[0020] [u α1 u β1 u α2 u β2 ] T =T[u a u b u c u d u e ] T (1)

[0021]

[0022] According to the calculation results of formulas (1) and (2), the 30 effective voltage vectors on the two planes α1-β1 and α2-β2 can be divided into large vectors, medium vectors, small vectors, and zero vectors according to their amplitudes. The amplitudes of the large vectors, medium vectors, and small vectors are respectively...

[0023]

[0024] Among them, voltage vector U(3,6,7,12,14,17,19,24,25,28) is mapped to the 10 voltage vectors with the largest amplitude in the outermost ring on the α1-β1 plane, and to the 10 voltage vectors with the smallest amplitude in the innermost ring on the α2-β2 plane; voltage vector U(5,9,10,11,13,18,20,21,22,26) is mapped to the 10 voltage vectors with the smallest amplitude in the innermost ring on the α1-β1 plane, and to the 10 voltage vectors with the largest amplitude in the outermost ring on the α2-β2 plane; the other 10 effective voltage vectors maintain their amplitude unchanged in the mappings of the α1-β1 and α2-β2 planes, all being voltage vectors with medium amplitude in the middle ring, but their phases change; the two zero voltage vectors U(0,31) are mapped to the origin of the coordinate system in both planes;

[0025] (3) Selection of the volt-second balance vector

[0026] To ensure the independence of the two sets of given voltage vectors, the projection of the voltage vectors selected in the two subspaces onto the other subspace should be either a zero vector or a volt-second balanced vector. First, voltage vectors are selected in the α1-β1 plane, and a set of voltage vectors is constructed to achieve volt-second balance in the α2-β2 subspace. This results in a set of volt-second balanced voltage vectors, such that the average resultant voltage vector in the α1-β1 plane is not zero, and the average resultant voltage vector in the α2-β2 plane is zero. The method for constructing the volt-second balanced voltage vector in the α2-β2 plane is similar.

[0027] The following 10 α1-β1 plane volt-second balance vectors U′(3,6,7,12,14,17,19,24,25,28) are constructed using the 10 voltage vectors U(3,6,7,12,14,17,19,24,25,28) mapped to the α1-β1 plane with the largest amplitude.

[0028] The following 10 α2-β2 plane volt-second balance vectors U′(5,9,10,11,13,18,20,21,22,26) are constructed using the 10 largest voltage vectors U(5,9,10,11,13,18,20,21,22,26) mapped onto the α2-β2 plane;

[0029] (4) Sector determination

[0030] On the α1-β1 plane, starting from the α1 axis, the entire plane is divided into 10 sectors with intervals of 36°, and numbered sequentially in a counterclockwise direction as sector 1 to sector 10 of the α1-β1 plane; similarly, on the α2-β2 plane, starting from the α2 axis, the entire plane is divided into 10 sectors with intervals of 36°, and numbered sequentially in a counterclockwise direction as sector 1 to sector 10 of the α2-β2 plane;

[0031] Let u be the reference voltage vector that the five-phase voltage source inverter needs to modulate. ref =[u a u b u c u d u e ] T Through coordinate transformation, the data can be mapped onto two planes, α1-β1 and α2-β2, respectively. Let the reference voltage vectors to be modulated on the two sub-planes be:

[0032]

[0033] in, and These are the reference voltage vectors u ref The components projected onto the two planes α1-β1 and α2-β2 and These are the reference voltage vectors on the α1-β1 plane. The projection components of coordinate axes α1 and β1 in the coordinate system, and These are the reference voltage vectors on the α2-β2 plane. The projection components of the coordinate axes α2 and β2 in the coordinate system;

[0034] In the α1-β1 plane, based on the components of the reference voltage vector on the coordinate axes α1 and β1... For the reference voltage vector The sector in question is used for determination; similarly, on the α2-β2 plane, the components of the reference voltage vector on the coordinate axes α2 and β2 are used for determination. For the reference voltage vector The sector in question is determined.

[0035] (5) Calculate the duration of each voltage vector.

[0036] ① First, calculate the volt-second balance voltage vector U of the α1-β1 plane sector. x1 The duration of action T a Sector volt-second balance voltage vector U x2 The duration of action T bThe zero vector action time T0 is defined, and five intermediate time variables T are defined. x1 T x2 T x3 T x4 T x5 Let it satisfy the following calculation formula:

[0037]

[0038] Among them, T s For the switching period, in the α1-β1 plane sector, depending on the sector where the reference voltage is located, the volt-second balance voltage vector U x1 The duration of action T a Sector volt-second balance voltage vector U x2 The duration of action T b The relationships are shown in Table 1.

[0039] Table 1: Volt-second balance voltage vector U of each sector in the α1-β1 plane x1 U x2 Relationship of action time

[0040]

[0041]

[0042] In the α1-β1 plane, the sector base voltage vector U i1 The duration of action T1, the sector base voltage vector U i2 The duration of action T2, the sector base voltage vector U i3 The duration of action T3, the sector base voltage vector U i4 The formula for calculating the action time T4 is as follows:

[0043]

[0044] in

[0045] ② Calculate the volt-second balance voltage vector U of the α2-β2 plane sector. y1 The duration of action T c Sector volt-second balance voltage vector U y2 The duration of action T d Define five intermediate time variables T. y1 T y2 T y3 T y4 T y5 Let it satisfy the following calculation formula:

[0046]

[0047] Among them, T s For the switching period, in the α2-β2 plane sector, depending on the sector where the reference voltage is located, the volt-second balance voltage vector U y1 The duration of action T c Sector volt-second balance voltage vector U y2 The duration of action T d The relationships are shown in Table 2.

[0048] Table 2: Volt-second balance voltage vector U of each sector in the α2-β2 plane y1 U y2 Relationship of action time

[0049] sector 1 2 3 4 5 6 7 8 9 10 <![CDATA[T c ]]> <![CDATA[T y3 ]]> <![CDATA[-T y3 ]]> <![CDATA[T y4 ]]> <![CDATA[-T y4 ]]> <![CDATA[T y1 ]]> <![CDATA[-T y1 ]]> <![CDATA[-T y5 ]]> <![CDATA[T y5 ]]> <![CDATA[-T y2 ]]> <![CDATA[T y2 ]]> <![CDATA[T d ]]> <![CDATA[T y1 ]]> <![CDATA[T y5 ]]> <![CDATA[-T y5 ]]> <![CDATA[T y2 ]]> <![CDATA[-T y2 ]]> <![CDATA[-T y3 ]]> <![CDATA[T y3 ]]> <![CDATA[-T y4 ]]> <![CDATA[T y4 ]]> <![CDATA[-T y1 ]]>

[0050] In the α2-β2 plane, the sector base voltage vector U j1 Action time T5, sector base voltage vector U j2 Action time T6, sector base voltage vector U j3 Action time T7, sector base voltage vector U j4 The formula for calculating the action time T8 is as follows:

[0051]

[0052] ③ Finally, calculate the duration T0 of the zero-voltage vector. The formula is as follows:

[0053] T0 = ​​T s -T a -T b -T c -T d (9)

[0054] (6) Calculation of the volt-second balance voltage vector

[0055] To ensure the independence of the two plane composite reference voltage vectors, the average composite voltage vector of the volt-second balance voltage vector constructed on the α1-β1 plane is zero on the α2-β2 plane;

[0056] (7) Acquisition of driving signals

[0057] In a switching cycle T s The internal structure is divided into two parts to achieve wave generation, the front T s / 2 Based on the calculations of the α1-β1 plane, wave generation and subsequent T are performed. s / 2 Wave generation is performed based on the computational quantities of the α2-β2 plane, with one switching cycle T s The internal waveform uses an 11-segment transmission, specifically, the sector base voltage vector U corresponding to sector P1. i1 U i2 Ui3 U i4 The sector base voltage vector U corresponding to sector P2 j1 U j2 U j3 U j4 And two zero vectors U0 and U 31 The wave transmission sequence and conduction time are as follows:

[0058] Sections 1 and 11: The switching state combination (0, 0, 0, 0, 0) corresponding to the zero voltage vector U0 generates a wave, with a conduction time t1 = t 11 =T0 / 4;

[0059] Section 2: Sector Base Voltage Vector U i1 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t2=T1;

[0060] Section 3: Sector Base Voltage Vector U i2 Corresponding switch state combination (S) a S b S c S d S e Wave emission, conduction time t3=T2;

[0061] Section 4: Sector Base Voltage Vector U i3 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t4=T3;

[0062] Section 5: Sector Base Voltage Vector U i4 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t5 = T4;

[0063] Section 6: Zero Voltage Vector U 31 The corresponding switch state combination (1, 1, 1, 1, 1) generates a wave, and the conduction time t6 = T0 / 2;

[0064] Section 7: Sector Base Voltage Vector U j1 Corresponding switch state combination (S) a Sb S c S d S e Wave transmission, conduction time t7 = T5;

[0065] Section 8: Sector Base Voltage Vector U j2 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t8=T6;

[0066] Section 9: Sector Base Voltage Vector U j3 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t9 = T7;

[0067] Section 10: Sector Base Voltage Vector U j4 Corresponding switch state combination (S) a S b S c S d S e Wave emission, conduction time t 10 =T8;

[0068] This enables the voltage vector pulse width modulation output of a five-phase bearingless permanent magnet motor.

[0069] According to a preferred embodiment of the present invention, in step (1), the switching state combinations (S) corresponding to the 32 basic voltage vectors a ,S b ,S c ,S d ,S e The specific statuses are shown in Table 3:

[0070] Table 3: Switching State Combinations Corresponding to Base Voltage Vector

[0071]

[0072] According to a preferred embodiment of the present invention, the specific method for sector determination in step (4) is as follows:

[0073] 1) In the sector determination process on the α1-β1 plane, first define five intermediate variables for sector determination, namely A0, A1, A2, A3, and A4, and let the intermediate variables satisfy the following function:

[0074]

[0075] Define another intermediate variable P1 for sector determination, and let it satisfy the following function:

[0076] P1=10sign(A4)+8sign(A3)+4sign(A2)+2sign(A1)+sign(A0) (11)

[0077] In the formula, sign(x) is the sign function. When x>0, sign(x)=1; when x<0, sign(x)=0. Each value of the sixth intermediate variable P1 corresponds to a sector, as shown in Table 4.

[0078] Table 4: Correspondence between sectors on the P1 and α1-β1 plane

[0079] sector number 1 2 3 4 5 6 7 8 9 10 <![CDATA[P1]]> 7 17 25 21 19 18 8 0 4 6

[0080] 2) Similarly, in the sector determination process on the α2-β2 plane, we first define five intermediate variables for sector determination, namely B0, B1, B2, B3, and B4, and let the intermediate variables satisfy the following function:

[0081]

[0082] Define another intermediate variable P2 for sector determination, and let it satisfy the following function:

[0083] P2=10sign(B4)+8sign(B3)+4sign(B2)+2sign(B1)+sign(B0) (13)

[0084] Each value of the sixth intermediate variable P2 corresponds to a sector, as shown in Table 5.

[0085] Table 5: Correspondence between sectors on the P2 and α2-β2 plane

[0086] sector number 1 2 3 4 5 6 7 8 9 10 <![CDATA[P2]]> 7 17 25 21 19 18 8 0 4 6

[0087] In the 10 sectors on the α1-β1 plane, each sector uses a 2-volt-second balanced voltage vector relative to the reference voltage vector. The synthesis is performed, and the two volt-second balanced voltage vectors correspond to four basic voltage vectors. The reference voltage vector after sector judgment is recorded. The sector in question is any one of sectors 1 to 10, and this sector is denoted as sector X. The two volt-second balance voltage vectors corresponding to sector X are denoted as sector volt-second balance voltage vectors U in order of their sequence. x1 and sector volt-second balance voltage vector U x2The four base voltage vectors corresponding to sector X are denoted as sector base voltage vectors U in order of their sequence. i1 Sector base voltage vector U i2 Sector base voltage vector U i3 Sector base voltage vector U i4 The relationship between each sector and the sector volt-second balance voltage vector and the base voltage vector on the α1-β1 plane is shown in Table 6.

[0088] Table 6: Relationship between each sector and the sector volt-second balance voltage vector and base voltage vector on the α1-β1 plane

[0089]

[0090] In the 10 sectors on the α2-β2 plane, each sector uses a 2-volt-second balanced voltage vector relative to the reference voltage vector. The data is synthesized, and the two volt-second balanced voltage vectors correspond to the four base voltage vectors. The reference voltage vector after sector determination is recorded. The sector in question is any one of sectors 1 to 10, and this sector is denoted as sector Y. The two volt-second balance voltage vectors corresponding to sector X are denoted as sector volt-second balance voltage vectors U in order of their sequence. y1 and sector volt-second balance voltage vector U y2 The four base voltage vectors corresponding to sector Y are denoted as sector base voltage vectors U in order of their sequence. j1 Sector base voltage vector U j2 Sector base voltage vector U j3 Sector base voltage vector U j4 The relationship between each sector and the sector volt-second balance voltage vector and the base voltage vector on the α2-β2 plane is shown in Table 7.

[0091] Table 7: Relationship between each sector and the sector volt-second balance voltage vector and base voltage vector on the α2-β2 plane

[0092]

[0093] According to a preferred embodiment of the present invention, in step (6), the specific calculation process of the volt-second balance voltage vector is as follows: taking the volt-second balance voltage vector U′ on the α1-β1 plane as an example. 25 Taking the construction as an example, the basic voltage vector U 25 and its two adjacent base voltage vectors U 24 U 17 Merge the vectors and make the synthesized vector in the α2-β2 subspace zero. Assume that the volt-second equilibrium voltage vector synthesized in the α1-β1 plane is U′. 25 Its duration of action is T′ 25According to the volt-second balance principle, we can obtain:

[0094]

[0095] according to Figure 3 The vector distribution diagram shown indicates that |U 24 |=|U 17 |=|U 25 |=U max Calculations show that

[0096]

[0097] Based on the above calculation results, the synthesized volt-second balance voltage vector U′ can be obtained. 25 Amplitude in the α1-β1 plane:

[0098]

[0099] The beneficial effects of this invention are as follows:

[0100] To address the unique characteristics of SVPWM modulation for multiphase bearingless motors, this paper innovatively proposes to synthesize reference voltage vectors for two sub-planes separately using volt-second balanced voltage vectors. Compared to the matrix inversion method used in existing literature, this avoids the occurrence of negative values ​​in the voltage vector's duration. Attached Figure Description

[0101] Figure 1 This is a voltage vector distribution diagram of the phaseless motor of the present invention;

[0102] Figure 2 This is the voltage balance vector distribution diagram synthesized in this invention;

[0103] Figure 3 This is a voltage vector distribution diagram of the five-phase motor of the present invention;

[0104] Figure 4 The driving signals for each phase power element of the present invention are (torque voltage command located in sector 1, and floating voltage command located in sector 4).

[0105] Figure 5 This is a schematic diagram of the five-phase voltage-source inverter structure of the present invention;

[0106] Figure 6 This is a simulation verification diagram of the voltage vector action time of the present invention and the voltage vector conduction time of the prior art. Detailed Implementation

[0107] The present invention will be further described below with reference to the embodiments and accompanying drawings, but is not limited thereto.

[0108] Example 1:

[0109] This embodiment provides an SVPWM modulation strategy for a single-winding five-phase bearingless permanent magnet motor, and the implementation method is as follows:

[0110] (1) Setting of switch status and base voltage vector

[0111] Let S be the switching state signal of phase a in the five-phase bridge arm of a five-phase voltage source inverter. a The switching status signal of phase b bridge arm is S. b The switching status signal of phase C bridge arm is S. c The switching status signal of phase d bridge arm is S d The switching status signal of phase e bridge arm is S. e The value of the switch status signal is:

[0112] When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase a, S a =1; Upper arm switch is off, lower arm switch is on, S a =0;

[0113] When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase b, S b =1; Upper arm switch is off, lower arm switch is on, S b =0;

[0114] When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase c, S c =1; Upper arm switch is off, lower arm switch is on, S c =0;

[0115] When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase d, S d =1; Upper arm switch is off, lower arm switch is on, S d =0;

[0116] When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase e, S e =1; Upper arm switch is off, lower arm switch is on, S e =0;

[0117] Based on the switching states of the five-phase bridge arms of the five-phase voltage-source inverter, 32 basic voltage vectors are obtained, denoted as U0~U100~U200~U300~U400~U50~U60~U70~U80~U90~U1 ... 31 The switching state combinations corresponding to the 32 basic voltage vectors (S a ,S b ,S c ,S d ,S e The specific statuses are shown in Table 3:

[0118] Table 3: Switching State Combinations Corresponding to Base Voltage Vector

[0119]

[0120] (2) Vector space decoupling transformation

[0121] Using a constant amplitude coordinate transformation matrix T, the 32 basic voltage vectors of the five-phase inverter are projected onto two mutually orthogonal sub-planes, α1-β1 and α2-β2, respectively. All voltage vectors are based on the DC bus voltage V. dc The reference voltage is used for per-unit scaling to obtain the projection result as follows: Figure 1 As shown;

[0122] [u α1 u β1 u α2 u β2 ] T =T[u a u b u c u d u e ] T (1)

[0123]

[0124] According to the calculation results of formulas (1) and (2), the 30 effective voltage vectors on the two planes α1-β1 and α2-β2 can be divided into large vectors, medium vectors, small vectors, and zero vectors according to their amplitudes. The amplitudes of the large vectors, medium vectors, and small vectors are respectively...

[0125]

[0126] Among them, voltage vector U(3,6,7,12,14,17,19,24,25,28) is mapped to the 10 voltage vectors with the largest amplitude in the outermost ring on the α1-β1 plane, and to the 10 voltage vectors with the smallest amplitude in the innermost ring on the α2-β2 plane; voltage vector U(5,9,10,11,13,18,20,21,22,26) is mapped to the 10 voltage vectors with the smallest amplitude in the innermost ring on the α1-β1 plane, and to the 10 voltage vectors with the largest amplitude in the outermost ring on the α2-β2 plane; the other 10 effective voltage vectors maintain their amplitude unchanged in the mappings of the α1-β1 and α2-β2 planes, all being voltage vectors with medium amplitude in the middle ring, but their phases change; the two zero voltage vectors U(0,31) are mapped to the origin of the coordinate system in both planes;

[0127] (3) Selection of the volt-second balance vector

[0128] To ensure the independence of the two sets of given voltage vectors, the projection of the voltage vectors selected in the two subspaces onto the other subspace should be a zero vector or a volt-second balance vector. First, the voltage vectors in the α1-β1 plane are selected, starting from... Figure 1 It can be seen that there is no set of voltage vectors that makes its projection non-zero in the α1-β1 plane and zero in the α2-β2 plane. Therefore, when selecting voltage vectors in the α1-β1 plane in the algorithm, we consider constructing a set of voltage vectors that make them volt-second balanced in the α2-β2 subspace, that is, a set of volt-second balanced voltage vectors, so that their average composite voltage vector in the α1-β1 plane is non-zero and their average composite voltage vector in the α2-β2 plane is zero. The method for constructing the volt-second balanced voltage vector in the α2-β2 plane is similar.

[0129] The following 10 α1-β1 plane volt-second balance vectors U′(3,6,7,12,14,17,19,24,25,28) are constructed using the 10 voltage vectors U(3,6,7,12,14,17,19,24,25,28) mapped to the α1-β1 plane with the largest amplitude.

[0130] Using the ten voltage vectors U(5,9,10,11,13,18,20,21,22,26) mapped to the α2-β2 plane with the largest amplitudes, construct the following ten α2-β2 plane volt-second balance vectors U′(5,9,10,11,13,18,20,21,22,26), as follows: Figure 2 As shown, the α1-β1 plane volt-second balance vector is the harmonic space balance vector, and the α2-β2 plane volt-second balance vector is the fundamental wave balance vector;

[0131] (4) Sector determination

[0132] On the α1-β1 plane, starting from the α1 axis, the entire plane is divided into 10 sectors with intervals of 36°, and numbered sequentially in a counterclockwise direction as sector 1 to sector 10 of the α1-β1 plane; similarly, on the α2-β2 plane, starting from the α2 axis, the entire plane is divided into 10 sectors with intervals of 36°, and numbered sequentially in a counterclockwise direction as sector 1 to sector 10 of the α2-β2 plane;

[0133] Let u be the reference voltage vector that the five-phase voltage source inverter needs to modulate. ref =[u a u b u c u d u e ] T Through coordinate transformation, the data can be mapped onto two planes, α1-β1 and α2-β2, respectively. Let the reference voltage vectors to be modulated on the two sub-planes be:

[0134]

[0135] in, and These are the reference voltage vectors u ref The components projected onto the two planes α1-β1 and α2-β2

[0136] and These are the reference voltage vectors on the α1-β1 plane. The projection components of coordinate axes α1 and β1 in the coordinate system, and These are the reference voltage vectors on the α2-β2 plane. The projection components of the coordinate axes α2 and β2 in the coordinate system;

[0137] In the α1-β1 plane, based on the components of the reference voltage vector on the coordinate axes α1 and β1... For the reference voltage vector The sector in question is used for determination; similarly, on the α2-β2 plane, the components of the reference voltage vector on the coordinate axes α2 and β2 are used for determination. For the reference voltage vector Determine the sector in question;

[0138] The specific method for sector determination is as follows:

[0139] 1) In the sector determination process on the α1-β1 plane, first define five intermediate variables for sector determination, namely A0, A1, A2, A3, and A4, and let the intermediate variables satisfy the following function:

[0140]

[0141] Define another intermediate variable P1 for sector determination, and let it satisfy the following function:

[0142] P1=10sign(A4)+8sign(A3)+4sign(A2)+2sign(A1)+sign(A0) (11)

[0143] In the formula, sign(x) is the sign function. When x>0, sign(x)=1; when x<0, sign(x)=0. Each value of the sixth intermediate variable P1 corresponds to a sector, as shown in Table 4.

[0144] Table 4: Correspondence between sectors on the P1 and α1-β1 plane

[0145] sector number 1 2 3 4 5 6 7 8 9 10 <![CDATA[P1]]> 7 17 25 21 19 18 8 0 4 6

[0146] 2) Similarly, in the sector determination process on the α2-β2 plane, we first define five intermediate variables for sector determination, namely B0, B1, B2, B3, and B4, and let the intermediate variables satisfy the following function:

[0147]

[0148] Define another intermediate variable P2 for sector determination, and let it satisfy the following function:

[0149] P2=10sign(B4)+8sign(B3)+4sign(B2)+2sign(B1)+sign(B0) (13)

[0150] Each value of the sixth intermediate variable P2 corresponds to a sector, as shown in Table 5.

[0151] Table 5: Correspondence between sectors on the P2 and α2-β2 plane

[0152] sector number 1 2 3 4 5 6 7 8 9 10 <![CDATA[P2]]> 7 17 25 21 19 18 8 0 4 6

[0153] In the 10 sectors on the α1-β1 plane, each sector uses a 2-volt-second balanced voltage vector relative to the reference voltage vector. The synthesis is performed, and the two volt-second balanced voltage vectors correspond to four basic voltage vectors. The reference voltage vector after sector judgment is recorded. The sector in question is any one of sectors 1 to 10, and this sector is denoted as sector X. The two volt-second balance voltage vectors corresponding to sector X are denoted as sector volt-second balance voltage vectors U in order of their sequence. x1 and sector volt-second balance voltage vector U x2 The four base voltage vectors corresponding to sector X are denoted as sector base voltage vectors U in order of their sequence. i1 Sector base voltage vector U i2 Sector base voltage vector U i3 Sector base voltage vector U i4 The relationship between each sector and the sector volt-second balance voltage vector and the base voltage vector on the α1-β1 plane is shown in Table 6.

[0154] Table 6: Relationship between each sector and the sector volt-second balance voltage vector and base voltage vector on the α1-β1 plane

[0155]

[0156] In the 10 sectors on the α2-β2 plane, each sector uses a 2-volt-second balanced voltage vector relative to the reference voltage vector. The data is synthesized, and the two volt-second balanced voltage vectors correspond to the four base voltage vectors. The reference voltage vector after sector determination is recorded. The sector in question is any one of sectors 1 to 10, and this sector is denoted as sector Y. The two volt-second balance voltage vectors corresponding to sector X are denoted as sector volt-second balance voltage vectors U in order of their sequence. y1 and sector volt-second balance voltage vector U y2 The four base voltage vectors corresponding to sector Y are denoted as sector base voltage vectors U in order of their sequence. j1 Sector base voltage vector U j2 Sector base voltage vector U j3 Sector base voltage vector U j4 The relationship between each sector and the sector volt-second balance voltage vector and the base voltage vector on the α2-β2 plane is shown in Table 7.

[0157] Table 7: Relationship between each sector and the sector volt-second balance voltage vector and base voltage vector on the α2-β2 plane

[0158]

[0159] (5) Calculate the duration of each voltage vector.

[0160] ① First, calculate the volt-second balance voltage vector U of the α1-β1 plane sector. x1 The duration of action T a Sector volt-second balance voltage vector U x2 The duration of action T b The zero vector action time T0 is defined, and five intermediate time variables T are defined. x1 T x2 T x3 T x4 T x5 Let it satisfy the following calculation formula:

[0161]

[0162] Among them, T s For the switching period, in the α1-β1 plane sector, depending on the sector where the reference voltage is located, the volt-second balance voltage vector U x1 The duration of action T a Sector volt-second balance voltage vector U x2 The duration of action T b The relationships are shown in Table 1.

[0163] Table 1: Volt-second balance voltage vector U of each sector in the α1-β1 plane x1 U x2 Relationship of action time

[0164] sector 1 2 3 4 5 6 7 8 9 10 <![CDATA[T a ]]> <![CDATA[T x3 ]]> <![CDATA[-T x3 ]]> <![CDATA[T x4 ]]> <![CDATA[-T x4 ]]> <![CDATA[T x1 ]]> <![CDATA[-T x1 ]]> <![CDATA[-T x5 ]]> <![CDATA[T x5 ]]> <![CDATA[-T x2 ]]> <![CDATA[T x2 ]]> <![CDATA[T b ]]> <![CDATA[T x1 ]]> <![CDATA[T x5 ]]> <![CDATA[-T x5 ]]> <![CDATA[T x2 ]]> <![CDATA[-T x2 ]]> <![CDATA[-T x3 ]]> <![CDATA[T x3 ]]> <![CDATA[-T x4 ]]> <![CDATA[T x4 ]]> <![CDATA[-T x1 ]]>

[0165] In the α1-β1 plane, the sector base voltage vector U i1 The duration of action T1, the sector base voltage vector U i2 The duration of action T2, the sector base voltage vector U i3 The duration of action T3, the sector base voltage vector U i4 The formula for calculating the action time T4 is as follows:

[0166]

[0167] in

[0168] ② Calculate the volt-second balance voltage vector U of the α2-β2 plane sector. y1 The duration of action T c Sector volt-second balance voltage vector U y2 The duration of action T d Define five intermediate time variables T. y1 T y2 T y3 T y4 T y5 Let it satisfy the following calculation formula:

[0169]

[0170] Among them, T s For the switching period, in the α2-β2 plane sector, depending on the sector where the reference voltage is located, the volt-second balance voltage vector U y1 The duration of action T c Sector volt-second balance voltage vector U y2 The duration of action T d The relationships are shown in Table 2.

[0171] Table 2: Volt-second balance voltage vector U of each sector in the α2-β2 plane y1 U y2 Relationship of action time

[0172] sector 1 2 3 4 5 6 7 8 9 10 <![CDATA[T c ]]> <![CDATA[T y3 ]]> <![CDATA[-T y3 ]]> <![CDATA[T y4 ]]> <![CDATA[-T y4 ]]> <![CDATA[T y1 ]]> <![CDATA[-T y1 ]]> <![CDATA[-T y5 ]]> <![CDATA[T y5 ]]> <![CDATA[-T y2 ]]> <![CDATA[T y2 ]]> <![CDATA[T d ]]> <![CDATA[T y1 ]]> <![CDATA[T y5 ]]> <![CDATA[-T y5 ]]> <![CDATA[T y2 ]]> <![CDATA[-T y2 ]]> <![CDATA[-T y3 ]]> <![CDATA[T y3 ]]> <![CDATA[-T y4 ]]> <![CDATA[T y4 ]]> <![CDATA[-T y1 ]]>

[0173] In the α2-β2 plane, the sector base voltage vector U j1 Action time T5, sector base voltage vector U j2 Action time T6, sector base voltage vector U j3 Action time T7, sector base voltage vector U j4 The formula for calculating the action time T8 is as follows:

[0174]

[0175] ③ Finally, calculate the duration T0 of the zero-voltage vector. The formula is as follows:

[0176] T0 = ​​T s -T a -T b -T c -T d (9)

[0177] (6) Calculation of the volt-second balance voltage vector

[0178] To ensure the independence of the two plane-synthesized reference voltage vectors, the average synthesized voltage vector in the α2-β2 plane of the volt-second balance voltage vector constructed in the α1-β1 plane is zero, with the volt-second balance voltage vector U′ in the α1-β1 plane as the reference vector. 25 Taking the construction as an example, the basic voltage vector U 25 and its two adjacent base voltage vectors U 24 U 17 Merge the vectors and make the synthesized vector in the α2-β2 subspace zero. Assume that the volt-second equilibrium voltage vector synthesized in the α1-β1 plane is U′. 25 Its duration of action is T′ 25 According to the volt-second balance principle, we can obtain:

[0179]

[0180] according to Figure 3 The vector distribution diagram shown indicates that |U 24 |=|U 17 |=|U 25 |=U max Calculations show that

[0181]

[0182] Based on the above calculation results, the magnitude of the synthesized volt-second balance voltage vector U2′5 in the α1-β1 plane can be obtained:

[0183]

[0184] (7) Acquisition of driving signals

[0185] In a switching cycle T s The internal structure is divided into two parts to achieve wave generation, the front T s / 2 Based on the calculations of the α1-β1 plane, wave generation and subsequent T are performed. s / 2 Wave generation is performed based on the computational quantities of the α2-β2 plane, with one switching cycle T s The internal waveform uses an 11-segment transmission, specifically, the sector base voltage vector U corresponding to sector P1.i1 U i2 U i3 U i4 The sector base voltage vector U corresponding to sector P2 j1 U j2 U j3 U j4 And two zero vectors U0 and U 31 The wave transmission sequence and conduction time are as follows:

[0186] Sections 1 and 11: The switching state combination (0, 0, 0, 0, 0) corresponding to the zero voltage vector U0 generates a wave, with a conduction time t1 = t 11 =T0 / 4;

[0187] Section 2: Sector Base Voltage Vector U i1 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t2=T1;

[0188] Section 3: Sector Base Voltage Vector U i2 Corresponding switch state combination (S) a S b S c S d S e Wave emission, conduction time t3=T2;

[0189] Section 4: Sector Base Voltage Vector U i3 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t4=T3;

[0190] Section 5: Sector Base Voltage Vector U i4 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t5 = T4;

[0191] Section 6: Zero Voltage Vector U 31 The corresponding switch state combination (1, 1, 1, 1, 1) generates a wave, and the conduction time t6 = T0 / 2;

[0192] Section 7: Sector Base Voltage Vector U j1Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t7 = T5;

[0193] Section 8: Sector Base Voltage Vector U j2 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t8=T6;

[0194] Section 9: Sector Base Voltage Vector U j3 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t9 = T7;

[0195] Section 10: Sector Base Voltage Vector U j4 Corresponding switch state combination (S) a S b S c S d S e Wave emission, conduction time t 10 =T8;

[0196] This enables the voltage vector pulse width modulation output of a five-phase bearingless permanent magnet motor.

[0197] Taking the torque plane voltage command in the first sector and the floating plane voltage command in the fourth sector as an example, the drive signals for each phase arm are given, such as... Figure 4 As shown in the figure, a switching cycle is divided into two parts: the first part is the voltage vector corresponding to the torque plane and its duration, and the second part is the voltage vector selected for the floating plane and its duration.

[0198] Simulations were performed on the voltage vector action time of this invention and the voltage vector conduction time of the prior art (using the existing literature "SVPWM control of a single-winding five-phase permanent magnet bearingless motor" mentioned in the background section). The results are as follows: Figure 6 As shown, Figure 6 (a) is a simulation verification diagram of the voltage vector conduction time of the prior art. Figure 6 (b) is a simulation verification diagram of the voltage vector action time of the present invention, from which... Figure 6It is known that negative values ​​may appear in the voltage vector conduction time solution of existing methods, while the voltage vector action time of the present invention is always positive, thus truly realizing the decoupling control of the torque plane and the suspension plane.

Claims

1. An SVPWM modulation strategy for a single-winding five-phase bearingless permanent magnet motor, characterized in that, The implementation method is as follows: (1) Setting of switch status and base voltage vector Let S be the switching state signal of phase a in the five-phase bridge arm of a five-phase voltage source inverter. a The switching status signal of phase b bridge arm is S. b The switching status signal of phase C bridge arm is S. c The switching status signal of phase d bridge arm is S. d The switching status signal of phase e bridge arm is S. e The value of the switch status signal is: When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase a, S a =1; Upper arm switch is off, lower arm switch is on, S a =0; When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase b, S b =1; Upper arm switch is off, lower arm switch is on, S b =0; When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase c, S c =1; Upper arm switch is off, lower arm switch is on, S c =0; When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase d, S d =1; Upper arm switch is off, lower arm switch is on, S d =0; When the upper bridge arm switch is turned on and the lower bridge arm switch is turned off in phase e, S e =1; Upper arm switch is off, lower arm switch is on, S e =0; Based on the switching states of the five-phase bridge arms of the five-phase voltage-source inverter, 32 basic voltage vectors are obtained, denoted as U0~U100~U200~U300~U400~U50~U60~U70~U80~U90~U1 ... 31 ; (2) Vector space decoupling transformation Using a constant amplitude coordinate transformation matrix T, the 32 basic voltage vectors of the five-phase inverter are projected onto two mutually orthogonal sub-planes, α1-β1 and α2-β2, respectively. All voltage vectors are based on the DC bus voltage V. dc Per-unit voltage is used as a reference voltage; [u α1 u β1 u α2 u β2 ] T =T[u a u b u c u d u e ] T (1) According to the calculation results of formulas (1) and (2), the 30 effective voltage vectors on the two planes α1-β1 and α2-β2 can be divided into large vectors, medium vectors, small vectors, and zero vectors according to their amplitudes. The amplitudes of the large vectors, medium vectors, and small vectors are respectively... Among them, voltage vector U(3,6,7,12,14,17,19,24,25,28) is mapped to the 10 voltage vectors with the largest amplitude in the outermost ring on the α1-β1 plane, and to the 10 voltage vectors with the smallest amplitude in the innermost ring on the α2-β2 plane; voltage vector U(5,9,10,11,13,18,20,21,22,26) is mapped to the 10 voltage vectors with the smallest amplitude in the innermost ring on the α1-β1 plane, and to the 10 voltage vectors with the largest amplitude in the outermost ring on the α2-β2 plane; the other 10 effective voltage vectors maintain their amplitude unchanged in the mappings of the α1-β1 and α2-β2 planes, all being voltage vectors with medium amplitude in the middle ring, but their phases change; the two zero voltage vectors U(0,31) are mapped to the origin of the coordinate system in both planes; (3) Selection of the volt-second balance vector First, select the voltage vector in the α1-β1 plane and construct a set of voltage vectors to achieve volt-second balance in the α2-β2 subspace, i.e., a set of volt-second balanced voltage vectors, so that the average composite voltage vector in the α1-β1 plane is not zero and the average composite voltage vector in the α2-β2 plane is zero. The method for constructing the volt-second balanced voltage vector in the α2-β2 plane is similar. The following 10 α1-β1 plane volt-second balance vectors U′(3,6,7,12,14,17,19,24,25,28) are constructed using the 10 voltage vectors U(3,6,7,12,14,17,19,24,25,28) mapped to the α1-β1 plane with the largest amplitude. The following 10 α2-β2 plane volt-second balance vectors U′(5,9,10,11,13,18,20,21,22,26) are constructed using the 10 largest voltage vectors U(5,9,10,11,13,18,20,21,22,26) mapped onto the α2-β2 plane; (4) Sector determination On the α1-β1 plane, starting from the α1 axis, the entire plane is divided into 10 sectors with intervals of 36°, and numbered sequentially in a counterclockwise direction as sector 1 to sector 10 of the α1-β1 plane; similarly, on the α2-β2 plane, starting from the α2 axis, the entire plane is divided into 10 sectors with intervals of 36°, and numbered sequentially in a counterclockwise direction as sector 1 to sector 10 of the α2-β2 plane; Let u be the reference voltage vector that the five-phase voltage source inverter needs to modulate. ref =[u a u b u c u d u e ] T Through coordinate transformation, the data can be mapped onto two planes, α1-β1 and α2-β2, respectively. Let the reference voltage vectors to be modulated on the two sub-planes be: in, and These are the reference voltage vectors u ref The components projected onto the two planes α1-β1 and α2-β2, u α1 and These are the reference voltage vectors on the α1-β1 plane. The projection components of coordinate axes α1 and β1 in the coordinate system, and These are the reference voltage vectors on the α2-β2 plane. The projection components of the coordinate axes α2 and β2 in the coordinate system; In the α1-β1 plane, based on the components of the reference voltage vector on the coordinate axes α1 and β1... For the reference voltage vector The sector in question is used for determination; similarly, on the α2-β2 plane, the components of the reference voltage vector on the coordinate axes α2 and β2 are used for determination. For the reference voltage vector Determine the sector in question; (5) Calculate the duration of each voltage vector. ① First, calculate the volt-second balance voltage vector U of the α1-β1 plane sector. x1 Duration T a Sector volt-second balance voltage vector U x2 The duration of action T b The zero vector action time T0 is defined, and five intermediate time variables T are defined. x1 T x2 T x3 T x4 T x5 Let it satisfy the following calculation formula: Among them, T s For the switching period, in the α1-β1 plane sector, depending on the sector where the reference voltage is located, the volt-second balance voltage vector U x1 The duration of action T a Sector volt-second balance voltage vector U x2 The duration of action T b The relationships are shown in Table 1. Table 1: Volt-second balance voltage vector U of each sector in the α1-β1 plane x1 U x2 Relationship of action time In the α1-β1 plane, the sector base voltage vector U i1 The duration of action T1, the sector base voltage vector U i2 The duration of action T2, the sector base voltage vector U i3 The duration of action T3, the sector base voltage vector U i4 The formula for calculating the action time T4 is as follows: in ② Calculate the volt-second balance voltage vector U of the α2-β2 plane sector. y1 The duration of action T c Sector volt-second balance voltage vector U y2 The duration of action T d Define five intermediate time variables T. y1 T y2 T y3 T y4 T y5 Let it satisfy the following calculation formula: Among them, T s For the switching period, in the α2-β2 plane sector, depending on the sector where the reference voltage is located, the volt-second balance voltage vector U y1 The duration of action T c Sector volt-second balance voltage vector U y2 The duration of action T d The relationships are shown in Table 2. Table 2: Volt-second balance voltage vector U of each sector in the α2-β2 plane y1 U y2 Relationship of action time In the α2-β2 plane, the sector base voltage vector U j1 Action time T5, sector base voltage vector U j2 Action time T6, sector base voltage vector U j3 Action time T7, sector base voltage vector U j4 The formula for calculating the action time T8 is as follows: ③ Finally, calculate the duration T0 of the zero-voltage vector. The formula is as follows: T0=T s -T a -T b -T c -T d (9) (6) Calculation of the volt-second balance voltage vector To ensure the independence of the two plane composite reference voltage vectors, the average composite voltage vector of the volt-second balance voltage vector constructed on the α1-β1 plane is zero on the α2-β2 plane; (7) Acquisition of driving signals In a switching cycle T s The internal structure is divided into two parts to achieve wave generation, the front T s / 2 Based on the calculations of the α1-β1 plane, wave generation and subsequent T are performed. s / 2 Wave generation is performed based on the computational quantities of the α2-β2 plane, with one switching cycle T s The internal waveform uses an 11-segment transmission, specifically, the sector base voltage vector U corresponding to sector P1. i1 U i2 U i3 U i4 The sector base voltage vector U corresponding to sector P2 j1 U j2 U j3 U j4 And two zero vectors U0 and U 31 The wave transmission sequence and conduction time are as follows: Sections 1 and 11: The switching state combination (0, 0, 0, 0, 0) corresponding to the zero voltage vector U0 generates a wave, with a conduction time t1 = t 11 =T0 / 4; Section 2: Sector Base Voltage Vector U i1 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t2=T1; Section 3: Sector Base Voltage Vector U i2 Corresponding switch state combination (S) a S b S c S d S e Wave emission, conduction time t3=T2; Section 4: Sector Base Voltage Vector U i3 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t4=T3; Section 5: Sector Base Voltage Vector U i4 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t5 = T4; Section 6: Zero Voltage Vector U 31 The corresponding switch state combination (1, 1, 1, 1, 1) generates a wave, and the conduction time t6 = T0 / 2; Section 7: Sector Base Voltage Vector U j1 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t7 = T5; Section 8: Sector Base Voltage Vector U j2 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t8=T6; Section 9: Sector Base Voltage Vector U j3 Corresponding switch state combination (S) a S b S c S d S e Wave transmission, conduction time t9 = T7; Section 10: Sector Base Voltage Vector U j4 Corresponding switch state combination (S) a S b S c S d S e Wave emission, conduction time t 10 =T8; This enables the voltage vector pulse width modulation output of a five-phase bearingless permanent magnet motor.

2. The SVPWM modulation strategy for a single-winding five-phase bearingless permanent magnet motor as described in claim 1, characterized in that, In step (1), the switching state combinations (S) corresponding to the 32 basic voltage vectors a ,S b ,S c ,S d ,S e The specific status of ) is shown in Table 3: Table 3: Switching State Combinations Corresponding to Base Voltage Vector 3. The SVPWM modulation strategy for a single-winding five-phase bearingless permanent magnet motor as described in claim 1, characterized in that, In step (4), the specific method for sector determination is as follows: 1) In the sector determination process on the α1-β1 plane, first define five intermediate variables for sector determination, namely A0, A1, A2, A3, and A4, and let the intermediate variables satisfy the following function: Define another intermediate variable P1 for sector determination, and let it satisfy the following function: P1=10sign(A4)+8sign(A3)+4sign(A2)+2sign(A1)+sign(A0)(11) In the formula, sign(x) is the sign function. When x>0, sign(x)=1; when x<0, sign(x)=0. Each value of the sixth intermediate variable P1 corresponds to a sector, as shown in Table 4. Table 4: Correspondence between sectors on the P1 and α1-β1 plane 2) Similarly, in the sector determination process on the α2-β2 plane, we first define five intermediate variables for sector determination, namely B0, B1, B2, B3, and B4, and let the intermediate variables satisfy the following function: Define another intermediate variable P2 for sector determination, and let it satisfy the following function: P2=10sign(B4)+8sign(B3)+4sign(B2)+2sign(B1)+sign(B0)(13) Each value of the sixth intermediate variable P2 corresponds to a sector, as shown in Table 5. Table 5: Correspondence between sectors on the P2 and α2-β2 plane In the 10 sectors on the α1-β1 plane, each sector uses a 2-volt-second balanced voltage vector relative to the reference voltage vector. The synthesis is performed, and the two volt-second balanced voltage vectors correspond to four basic voltage vectors. The reference voltage vector after sector judgment is recorded. The sector in question is any one of sectors 1 to 10, and this sector is denoted as sector X. The two volt-second balance voltage vectors corresponding to sector X are denoted as sector volt-second balance voltage vectors U in order of their sequence. x1 and sector volt-second balance voltage vector U x2 The four base voltage vectors corresponding to sector X are denoted as sector base voltage vectors U in order of their sequence. i1 Sector base voltage vector U i2 Sector base voltage vector U i3 Sector base voltage vector U i4 The relationship between each sector and the sector volt-second balance voltage vector and the base voltage vector on the α1-β1 plane is shown in Table 6. Table 6: Relationship between each sector and the sector volt-second balance voltage vector and base voltage vector on the α1-β1 plane In the 10 sectors on the α2-β2 plane, each sector uses a 2-volt-second balanced voltage vector relative to the reference voltage vector. The synthesis is performed, and the two volt-second balanced voltage vectors correspond to four basic voltage vectors. The reference voltage vector after sector judgment is recorded. The sector in question is any one of sectors 1 to 10, and this sector is denoted as sector Y. The two volt-second balance voltage vectors corresponding to sector X are denoted as sector volt-second balance voltage vectors U in order of their sequence. y1 and sector volt-second balance voltage vector U y2 The four base voltage vectors corresponding to sector Y are denoted as sector base voltage vectors U in order of their sequence. j1 Sector base voltage vector U j2 Sector base voltage vector U j3 Sector base voltage vector U j4 The relationship between each sector and the sector volt-second balance voltage vector and the base voltage vector on the α2-β2 plane is shown in Table 7. Table 7: Relationship between each sector and the sector volt-second balance voltage vector and base voltage vector on the α2-β2 plane 4. The SVPWM modulation strategy for a single-winding five-phase bearingless permanent magnet motor as described in claim 1, characterized in that, In step (6), the specific calculation process of the volt-second balance voltage vector is as follows: taking the volt-second balance voltage vector U′ on the α1-β1 plane as an example. 25 Taking the construction as an example, the basic voltage vector U 25 and its two adjacent base voltage vectors U 24 U 17 Merge the vectors and make the synthesized vector in the α2-β2 subspace zero. Assume that the volt-second equilibrium voltage vector synthesized in the α1-β1 plane is U′. 25 Its duration of action is T′ 25 According to the volt-second balance principle, we can obtain: According to the vector distribution diagram, |U 24 |=|U 17 |=|U 25 |=U max Calculations show that Based on the above calculation results, the synthesized volt-second balance voltage vector U′ can be obtained. 25 Amplitude in the α1-β1 plane:

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