Dual three-phase permanent magnet synchronous motor switching control method based on single current sensor sampling

Abstract

The invention discloses a dual three-phase permanent magnet synchronous motor switching control method based on single current sensor sampling, solves the problem that phase current reconstruction in a transient switching transition process is difficult due to switching operation of a DTP-PMSM single current sensor current reconstruction low modulation ratio region and a normal region, and belongs to the field of motor driving. The method comprises the steps that in a low modulation ratio area, three-phase windings XYZ operate independently, current between X-phase upper bridge arms and Y-phase upper bridge arms is sampled, three-phase current is reconstructed, the reconstructed current and the sampling rotating speed are sent into a loop to obtain modulation reference voltage, and then power module driving is completed through modulation; in a normal modulation ratio area, the two sets of three-phase windings operate cooperatively, the sum of the current between the X-phase upper bridge arm and the Y-phase upper bridge arm and the current between the A-phase lower bridge arm and the B-phase lower bridge arm is sampled at different sampling vector combination positions, six-phase current reconstruction is carried out, the reconstructed current and the sampling rotating speed are sent into a loop, modulation reference voltage is obtained, and power module driving is completed through modulation after amplitude limiting.

Description

Technical Field

[0001] The invention relates to a dual three-phase permanent magnet synchronous motor switching control method based on single current sensor sampling, and belongs to the field of motor driving. Background Art

[0002] High-power permanent magnet synchronous motors (PMSM) are widely used in ship propulsion, vehicle drive, aerospace, wind power generation and other fields due to their high power density, high operating efficiency, high control accuracy, and low operating noise. However, in the face of increasingly complex working conditions and specific application environments, traditional motor designs can no longer meet the optimal performance in all scenarios. Therefore, motor technology has begun to develop in a more specialized direction, aiming to better adapt to the specific needs of different industries through structural innovation, material optimization, and improved control strategies. Among them, the transformation from three-phase PMSM to dual three-phase permanent magnet synchronous motor (DTP-PMSM) is a vivid example of this process.

[0003] To achieve precise control of DTP-PMSM, it is necessary to collect information about the six phase currents. The traditional method of collecting phase current information is usually to insert current sensors between the corresponding phase lines, but this method not only increases the hardware cost, but also increases the size of the driver itself and the complexity of the hardware structure. In order to reduce hardware costs and improve system reliability, researchers began to explore the use of a single current sensor to reconstruct the phase current of a multi-phase motor.

[0004] However, current reconstruction often faces the problem of current reconstruction blind spots in low modulation ratio areas. Traditional solutions to eliminate the current reconstruction blind spots in low modulation ratio areas include: measurement pulse insertion method, vector phase shift method, dynamic zero-state pulse width modulation method, etc. For DTP-PMSM, if the PWM modification in the low modulation ratio area is performed according to the traditional solution, both sets of three-phase windings need to be modified. The negative impact on the electric drive system caused by the superposition of two sets of three-phase windings will be more serious, and this solution does not fully utilize the characteristics of DTP-PMSM.

[0005] When the DTP-PMSM vector control frequency conversion system has different methods to eliminate the blind spots of current reconstruction with different modulation ratios, it is necessary to give clear and efficient switching control methods for different reconstruction schemes. The switching of traditional current reconstruction schemes under different modulation ratios may bring about the problem of difficulty in reconstructing phase current in a wide modulation ratio range, and there is room for further optimization.

[0006] In the normal modulation ratio area of ​​the actual motor drive system, due to the delay characteristics of the motor angular position acquisition system, the position information used for transformation in the control loop is biased, which in turn leads to an increase in reactive voltage and an increase in current under the same torque output. This ultimately affects the maximum torque-to-current ratio output. To this end, scholars have proposed a variety of compensation methods. However, due to the upper and lower or internal and external deviations in the winding positions of the two sets of three-phase windings in the actual DTP-PMSM, new challenges have been brought to the delay compensation of the DTP-PMSM rotary transformer. Summary of the invention

[0007] Aiming at the problem that the phase current is difficult to reconstruct during the transient switching transition process when the single current sensor current of a dual three-phase permanent magnet synchronous motor switches between the low modulation ratio area and the normal area, the present invention provides a switching control method for a dual three-phase permanent magnet synchronous motor.

[0008] A dual three-phase permanent magnet synchronous motor switching control method based on single current sensor sampling of the present invention comprises:

[0009] Step 1: In the low modulation ratio area, the three-phase winding XYZ operates independently, the three-phase winding ABC is subjected to wave sealing processing, a single current sensor is used to sample the current between the upper bridge arms of the X and Y phases in the three-phase winding XYZ, and the low modulation ratio three-phase current reconstruction is completed according to the three-phase current reconstruction expression in the low modulation ratio area; the reconstructed three-phase current and the sampled speed are sent into the loop for calculation to obtain the three-phase modulation reference voltage, and the power module is driven by low modulation ratio mixed pulse width modulation;

[0010] Step 2: Calculate the minimum sampling vector |U according to the minimum sampling time Min |, determine the reference voltage modulus value of the three-phase winding XYX|u ref-XYZ |Is it satisfied? |u ref-XYZ |≤2.1|U Min |, if yes, return to step 1, if no, go to step 3;

[0011] Step 3, in the normal modulation ratio area, the two sets of three-phase windings are operated in coordination, and a single current sensor is used to sample the sum of the current between the upper bridge arms of the X and Y phases in the three-phase winding XYZ and the current between the lower bridge arms of the A and B phases in the three-phase winding ABC at different sampling vector combinations, and the six-phase current reconstruction is completed according to the six-phase current reconstruction expression in the normal modulation ratio area, and the reconstructed six-phase current and the sampling speed are sent into the loop for calculation to obtain the modulation reference voltage, and the modulation reference voltage of the quadrature axis is limited, and then all the modulation reference voltages are subjected to hybrid pulse width modulation RHPWM to complete the power module drive;

[0012] Step 4: Determine the reference voltage modulus of the three-phase winding XYZ |u ref-XYZ |Is it satisfied? |u ref-XYZ |≤1.1|UMin |, if yes, go to step 1, if no, go to step 3.

[0013] Preferably, the method for obtaining the reconstruction expression of the three-phase current in the low modulation ratio area includes:

[0014] S A , S B , S C , S X , S Y , S Z They are the six-phase bridge arm switching functions of the dual three-phase permanent magnet synchronous motor, a value of 0 represents the lower bridge arm is turned on, and a value of 1 represents the upper bridge arm is turned on;

[0015] When S A =0, S B =0, S C =0 or S X =0, S Y =0, S Z =0 when the corresponding voltage vector U 0 ;

[0016] When S A =1, S B =0, S C =0 or S X =1, S Y =0, S Z =0 when the corresponding voltage vector U 1 ;

[0017] When S A =1, S B =1, S C =0 or S X =1, S Y =1, S Z =0 when the corresponding voltage vector U 2 ;

[0018] When S A =0, S B =1, S C =0 or S X =0, S Y =1, S Z =0 when the corresponding voltage vector U 3 ;

[0019] When S A =0, S B =1, S C =1 or S X =0, S Y =1, S Z =1 corresponds to the voltage vector U 4 ;

[0020] When S A =0, S B =0, S C =1 or S X =0, S Y =0, S Z =1 corresponds to the voltage vector U 5 ;

[0021] When S A =1, S B =0, S C =1 or S X =1, S Y =0, S Z =1 corresponds to the voltage vector U 6 ;

[0022] When S A =1, S B =1, S C =1 or S X =1, S Y =1, S Z =1 corresponds to the voltage vector U 7 ;

[0023] Voltage vector U 1 With voltage vector U 2 The area enclosed in space is the low modulation ratio reconstruction area L1;

[0024] Voltage vector U 2 With voltage vector U 3 The area enclosed in space is the low modulation ratio reconstruction area L2;

[0025] Voltage vector U 3 With voltage vector U 4 The area enclosed in space is the low modulation ratio reconstruction area L3;

[0026] Voltage vector U 4 With voltage vector U 5 The area enclosed in space is the low modulation ratio reconstruction area L4;

[0027] Voltage vector U 5 With voltage vector U 6 The area enclosed in space is the low modulation ratio reconstruction area L5;

[0028] Voltage vector U 6 With voltage vector U 1 The area enclosed in space is the low modulation ratio reconstruction area L6;

[0029] According to the different low modulation ratio reconstruction regions where the reference voltage is located, the three-phase current reconstruction expression is determined:

[0030]

[0031] Among them, 0T s , 0.5T s Represents a switching cycle T s Two sampling moments within ;

[0032] i X Indicates the current of phase X in the three-phase winding XYZ;

[0033] i Y Indicates the current of phase Y in three-phase winding XYZ

[0034] i Z Represents the current of phase Z in the three-phase winding XYZ.

[0035] Preferably, the low modulation ratio hybrid pulse width modulation comprises:

[0036] When the reference voltage vector is located in the low modulation ratio reconstruction area L1 or L4, the voltage vector U of the three-phase winding XYZ is 0 , U 7 Replaced by voltage vector U 6 , U 3 ;

[0037] When the reference voltage vector is located in the low modulation ratio reconstruction area L2, the voltage vector U of the three-phase winding XYZ is 0 , U 7 Replaced by voltage vector U 5 , U 2 ;

[0038] When the reference voltage vector is located in the low modulation ratio reconstruction area L3 or L6, the voltage vector U of the three-phase winding XYZ is 0 , U 7 Replaced by voltage vector U 2 , U 5 ;

[0039] When the reference voltage vector is located in the low modulation ratio reconstruction area L5, the voltage vector U of the three-phase winding XYZ is 0 , U 7 Replaced by voltage vector U 3 , U 6 .

[0040] Preferably, the method for obtaining the six-phase current reconstruction expression in the modulation ratio normal area includes:

[0041] S A , SB , S C , S X , S Y , S Z They are the six-phase bridge arm switching functions of the dual three-phase permanent magnet synchronous motor, a value of 0 represents the lower bridge arm is turned on, and a value of 1 represents the upper bridge arm is turned on;

[0042] When S A =0, S B =0, S C =0 or S X =0, S Y =0, S Z =0 when the corresponding voltage vector U 0 ;

[0043] When S A =1, S B =0, S C =0 or S X =1, S Y =0, S Z =0 when the corresponding voltage vector U 1 ;

[0044] When S A =1, S B =1, S C =0 or S X =1, S Y =1, S Z =0 when the corresponding voltage vector U 2 ;

[0045] When S A =0, S B =1, S C =0 or S X =0, S Y =1, S Z =0 when the corresponding voltage vector U 3 ;

[0046] When S A =0, S B =1, S C =1 or S X =0, S Y =1, S Z =1 corresponds to the voltage vector U 4 ;

[0047] When S A =0, S B =0, S C =1 or S X =0, S Y =0, S Z=1 corresponds to the voltage vector U 5 ;

[0048] When S A =1, S B =0, S C =1 or S X =1, S Y =0, S Z =1 corresponds to the voltage vector U 6 ;

[0049] When S A =1, S B =1, S C =1 or S X =1, S Y =1, S Z =1 corresponds to the voltage vector U 7 ;

[0050] Voltage vector U 1 With voltage vector U 2 The area enclosed in space is sector I;

[0051] Voltage vector U 2 With voltage vector U 3 The area enclosed in space is sector II;

[0052] Voltage vector U 3 With voltage vector U 4 The area enclosed in space is sector III;

[0053] Voltage vector U 4 With voltage vector U 5 The area enclosed in space is sector IV;

[0054] Voltage vector U 5 With voltage vector U 6 The area enclosed in space is sector V;

[0055] Voltage vector U 6 With voltage vector U 1 The area enclosed in space is sector VI;

[0056] Take the midline of sectors I to VI respectively, and the area surrounded by the midline of sector I and the midline of sector VI is the normal modulation ratio area G1;

[0057] The area surrounded by the midline of sector II and the midline of sector I is the normal modulation ratio area G2;

[0058] The area surrounded by the midline of sector II and the midline of sector III is the modulation ratio normal area G3;

[0059] The area surrounded by the midline of sector III and the midline of sector IV is the modulation ratio normal area G4;

[0060] The area surrounded by the midline of sector IV and the midline of sector V is the modulation ratio normal area G5;

[0061] The area surrounded by the midline of sector V and the midline of sector VI is the modulation ratio normal area G6;

[0062] Among them, the modulation ratio normal area G1 and the modulation ratio normal area G4 are zero vector modification areas, the modulation ratio normal area G1 includes the modulation ratio normal area G1-Ⅰ and the modulation ratio normal area G1-Ⅱ, the dividing line of sector VI and the voltage vector U 1 The area surrounded by the modulation ratio is the normal area G1-Ⅰ, the center line of sector Ⅰ and the voltage vector U 1 The enclosed area is the modulation ratio normal area G1-Ⅱ;

[0063] The modulation ratio normal region G4 includes the modulation ratio normal region G4-I and the modulation ratio normal region G4-II. The center line of sector III and the voltage vector U 4 The area surrounded by the modulation ratio is the normal area G4-Ⅰ, the center line of sector Ⅳ and the voltage vector U 4 The enclosed area is the modulation ratio normal area G4-Ⅱ;

[0064] The six-phase current reconstruction expression in the normal modulation area is:

[0065]

[0066]

[0067] Among them, ABC-U i XYZ-U j Indicates the switching period T s The voltage vector corresponding to the inner three-phase winding ABC is U i , the voltage vector corresponding to the three-phase winding XYZ is U j , i=0,1,2,3,4,5,6,7, j=0,1,2,3,4,5,6,7;

[0068] I 1 ,I 2 ,I 3 ,I 4 Respectively represent the current sampled by the four sampling vector combinations; i X Represents the current of phase X in the three-phase winding XYZ; i Y Represents the current of phase Y in the three-phase winding XYZ; i ZRepresents the current of phase Z in the three-phase winding XYZ; i A Represents the current of phase A in the three-phase winding ABC; i B Represents the current of phase B in three-phase winding ABC; i C Represents the current of phase C in the three-phase winding ABC.

[0069] Preferably, the hybrid pulse width modulation RHPWM comprises:

[0070] Shift the carrier of three-phase winding XYZ by 0.25T s In the modulation ratio normal area G1-Ⅰ and the modulation ratio normal area G4-Ⅰ, dynamic zero-state PWM modulation is applied to change the voltage vector U 0 , U 7 Replaced by voltage vector U 2 、Voltage vector U 5 ;

[0071] In the modulation ratio normal area G1-Ⅱ and the modulation ratio normal area G4-Ⅱ, dynamic zero-state PWM modulation is applied to change the voltage vector U 0 , U 7 Replaced by voltage vector U 6 、Voltage vector U 3 ;

[0072] In the normal modulation ratio area G2, G3, G5, and G6, SVPWM is used for modulation.

[0073] As a preference, the modulation reference voltage of the quadrature axis is limited:

[0074]

[0075] U q is the modulation reference voltage of the quadrature axis, T s represents the switching period, T min Indicates the minimum sampling time, U dc Indicates the bus voltage.

[0076] Preferably, when the modulation ratio is in a normal region, the method for acquiring the sampling rotation speed comprises:

[0077] The theoretical estimate of the direct-axis voltage output by the current loop controller ACR-PI is:

[0078]

[0079] Where: is the theoretical estimated value of the direct-axis voltage of the first set of three-phase windings; is the direct-axis voltage of the second three-phase winding; i d1 is the theoretical estimated value of the direct-axis current of the first three-phase winding; i d2is the direct-axis current of the second three-phase winding; i q1 is the theoretical estimated value of the first set of three-phase winding quadrature-axis current; i q2 is the quadrature-axis current of the second three-phase winding; L d is the direct axis inductance of the rotating coordinate system; L q is the quadrature axis inductance of the rotating coordinate system; L m is the stator excitation inductance; ω is the electrical angle; R s is the stator resistance;

[0080] For a given value of flux voltage u d1 、u d2 Filter and get the filtered voltage u d1-LPF 、u d2-LPF ;

[0081] The voltage error is obtained:

[0082]

[0083] Sum the direct-axis voltage errors of the two sets of three-phase windings to obtain u d-error , as the basis for resolver compensation:

[0084] u d-error =|u d1-error +u d2-error |

[0085] According to the magnitude of the direct axis voltage, the initial position angle θ of the motor 0 Perform resolver compensation to make the error and u d-error When the minimum value is reached, the position angle θ after compensation is saved, and the sampling speed ω after resolver compensation is obtained according to the position angle θ. m .

[0086] The beneficial effects of the present invention are as follows: for the problem that the switching operation between the low modulation ratio area and the normal area of ​​the current reconstruction of a single current sensor of a DTP-PMSM leads to difficulty in reconstructing the phase current during the transient switching transition process, the switching control method under different modulation ratios provided by the present invention can realize the phase current reconstruction in a wide modulation ratio range; the present invention can realize the phase current reconstruction in the low modulation ratio area of ​​a single current sensor of a DTP-PMSM drive system; the present invention provides a rotary transformer delay compensation method based on the characteristics of the DTP-PMSM. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Figure 1 is the switching control block diagram of the dual three-phase permanent magnet synchronous motor DTP-PMSM switching control method, where θ 0 is the DTP-PMSM electrical angle before compensation, θ is the DTP-PMSM electrical angle after compensation, ω is the DTP-PMSM electrical angular velocity, I SAMPLE is the current Hall sampling value;

[0088] Figure 2 It is the switching control flow chart of dual three-phase permanent magnet synchronous motor under different modulation ratios;

[0089] Figure 3 Reconstruct the topology diagram for DTP-PMSM current;

[0090] Figure 4 Reconstructing regions for low and normal modulation ratios;

[0091] FIG5(a) is a diagram showing the carrier and PWM waveforms of the low modulation ratio reconstruction area L1 of the three-phase winding in the low modulation ratio area XYZ;

[0092] FIG5( b ) is a diagram showing the carrier and PWM waveforms of the low modulation ratio reconstruction area L2 of the three-phase winding in the low modulation ratio area XYZ;

[0093] FIG5(c) is a diagram showing the carrier and PWM waveforms of the low modulation ratio reconstruction area L3 of the three-phase winding in the low modulation ratio area XYZ;

[0094] Figure 6 It is the waveform diagram of the sampled current and the XYZ real phase current in the low modulation ratio area;

[0095] FIG7( a ) is a diagram showing the real phase current waveform in the low modulation ratio region XYZ;

[0096] FIG7( b ) is a diagram of the XYZ reconstructed phase current waveform in the low modulation ratio region;

[0097] Figure 7(c) shows the error between the real current and the reconstructed current of phase X in the low modulation ratio region;

[0098] FIG8( a ) is a waveform diagram of the real phase current and the reconstructed phase current of ABC with different modulation ratio area switching;

[0099] FIG8( b ) is a diagram showing the XYZ real phase current and reconstructed phase current waveforms when switching between different modulation ratio regions;

[0100] Figure 8(c) The error between the real current and the reconstructed current of phase X when switching between different modulation ratio regions;

[0101] Figure 9(a) is the XYZ real phase current waveform of the motor starting in the low modulation ratio area;

[0102] Figure 9(b) is the XYZ reconstructed phase current waveform of the motor starting in the low modulation ratio area;

[0103] Figure 9(c) shows the error between the real current and the reconstructed current of the X-phase when the motor starts in the low modulation ratio area. DETAILED DESCRIPTION

[0104] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0105] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0106] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0107] The dual three-phase permanent magnet synchronous motor switching control method based on single current sensor sampling of this embodiment includes:

[0108] Step 1: In the low modulation operation area, the three-phase windings XYZ operate independently. The corresponding relationship between the current sensor sampling results and the phase current under different voltage vectors is:

[0109] I SAMPLE =S Y i Y +S Z i Z (1)

[0110] In the formula, S A , S B , S C , S X , S Y , S Z are the switching functions of the six-phase bridge arms, respectively. A value of 0 represents that the lower bridge arm is turned on, and a value of 1 represents that the upper bridge arm is turned on; i A Represents the current of phase A in the three-phase winding ABC; i B Represents the current of phase B in three-phase winding ABC; i C Represents the current of phase C in three-phase winding ABC; i X Represents the current of phase X in the three-phase winding XYZ; i Y Represents the current of phase Y in the three-phase winding XYZ; i Z Indicates the current of phase Z in the three-phase winding XYZ; I SAMPLE is the current sensor sampling value.

[0111] The reference voltage vector and the low modulation ratio reconstruction region are defined as follows:

[0112] When S A =0, S B =0, S C =0 or S X=0, S Y =0, S Z =0 when the corresponding voltage vector U 0 ;

[0113] When S A =1, S B =0, S C =0 or S X =1, S Y =0, S Z =0 when the corresponding voltage vector U 1 ;

[0114] When S A =1, S B =1, S C =0 or S X =1, S Y =1, S Z =0 when the corresponding voltage vector U 2 ;

[0115] When S A =0, S B =1, S C =0 or S X =0, S Y =1, S Z =0 when the corresponding voltage vector U 3 ;

[0116] When S A =0, S B =1, S C =1 or S X =0, S Y =1, S Z =1 corresponds to the voltage vector U 4 ;

[0117] When S A =0, S B =0, S C =1 or S X =0, S Y =0, S Z =1 corresponds to the voltage vector U 5 ;

[0118] When S A =1, S B =0, S C =1 or S X =1, S Y =0, S Z =1 corresponds to the voltage vector U 6 ;

[0119] When S A=1, S B =1, S C =1 or S X =1, S Y =1, S Z =1 corresponds to the voltage vector U 7 ;

[0120] Voltage vector U 1 With voltage vector U 2 The area enclosed in space is the low modulation ratio reconstruction area L1;

[0121] Voltage vector U 2 With voltage vector U 3 The area enclosed in space is the low modulation ratio reconstruction area L2;

[0122] Voltage vector U 3 With voltage vector U 4 The area enclosed in space is the low modulation ratio reconstruction area L3;

[0123] Voltage vector U 4 With voltage vector U 5 The area enclosed in space is the low modulation ratio reconstruction area L4;

[0124] Voltage vector U 5 With voltage vector U 6 The area enclosed in space is the low modulation ratio reconstruction area L5;

[0125] Voltage vector U 6 With voltage vector U 1 The area enclosed in space is the low modulation ratio reconstruction area L6;

[0126] When the motor runs in the low modulation ratio area, the low modulation ratio hybrid pulse width modulation LHPWM is used for modulation. LHPWM is: the three-phase winding ABC in the low modulation ratio area is sealed. When the reference voltage vector is located in the low modulation ratio reconstruction area L1 or the low modulation ratio reconstruction area L4, the zero vector U of the three phases XYZ is set. 0 , U 7 Replaced by the opposite effective vector U 6 , U 3 ; When the reference voltage vector is located at L2, the zero vector U of the three phases XYZ is 0 , U 7 Replaced by the opposite effective vector U 5 , U 2 When the reference voltage vector is located in the low modulation ratio reconstruction area L3 or the low modulation ratio reconstruction area L6, the zero vector U of the three phases XYZ 0 , U 7Replaced by the opposite effective vector U 2 , U 5 When the reference voltage vector is located in the low modulation ratio reconstruction area L5, the zero vector U of the XYZ three phases 0 , U 7 Replaced by the opposite effective vector U 3 , U 6 .

[0127] Sampling is performed at the beginning (0Ts) and the midpoint (0.5Ts) of the switching cycle Ts to obtain the sampling current I L1 with I L2 Substitute the sampled current into the current reconstruction expression in Table 1 to complete the XYZ three-phase current reconstruction.

[0128] Table 1 Correspondence between current sensor sampling results and phase current in low modulation ratio area

[0129]

[0130] This embodiment adopts a 30-pole motor with a rated speed of 125rpm, a motor flux of 0.89Wb, a DC-axis inductance of 7.1mH, and a stator excitation inductance of 5.1mH. A dual three-phase permanent magnet synchronous motor with a phase shift angle of 0° is used for simulation experiments. The switching frequency is 25kHz, and two sets of three-phase windings are independently connected in star shape. Figure 1 As shown, the main control loop adopts dual dq closed-loop control, and the control loop is reorganized according to the switching controller instructions.

[0131] Start the motor at a speed of 40r / min (0.32pu). Figure 2 From the motor switching control flow chart, it can be seen that when the motor starts, it first runs in the low modulation ratio area. Figure 1 In the low modulation ratio area shown, the independent three-phase windings XYZ work, the ABC torque current set value is 0, and the ABC drive is closed.

[0132] In the low modulation ratio area, LHPWM modulation is used to replace the zero vector with the opposite effective vector. Sampling is performed at the beginning (0Ts) and the midpoint (0.5Ts) of the switching cycle Ts to obtain the sampled current I L1 with I L2 Substitute the sampled current into the reconstruction expression to complete the XYZ low modulation ratio phase current reconstruction. Taking the low modulation ratio reconstruction area L1 as an example, the reconstruction process is explained. As shown in Figure 5(a), sampling is performed at 0Ts and 0.5Ts to obtain I L1 ,I L2 From Table 1, we can see that the reconstruction expression of the low modulation ratio reconstruction area L1 is formula (2). By substituting the sampled current into the three-phase current of XYZ, we can reconstruct the three-phase current of XYZ.

[0133]

[0134] Figure 7(a) to Figure 7(c) The phase current reconstruction results when operating in the low modulation ratio area are given. Under this condition, the three-phase reconstructed current still maintains a good sinusoidal property. According to the comparison results of the X-phase reconstructed current and the measured current and the error curve given in Figure 7(c), it can be seen that in the low modulation ratio area, the reconstructed current fundamental wave can still follow the actual current well.

[0135] During the starting process of the motor, it will inevitably pass through the low modulation ratio area, so it is necessary to verify the accuracy of the DTP-PMSM phase current reconstruction technology under this dynamic process.

[0136] Figure 9(a) to Figure 9(c) The phase current reconstruction results of the motor from zero speed and zero load to 40r / min (0.32pu) speed and 110N·m load in the dynamic process are given, where Figure 9(a) and Figure 9(b) are the actual and reconstructed current waveforms of the three-phase winding XYZ at this time. Figure 9(a) to Figure 9(c) It can be seen that the method proposed in this embodiment effectively eliminates the low modulation ratio reconstruction blind area. In the entire dynamic process, the three-phase reconstructed current of the DTP-PMSM can be smoothly started from the low modulation ratio area.

[0137] The collected angular position information is combined with the reconstructed XYZ three-phase current for coordinate transformation, and the three-phase current is sent to the Clark-Park transformation formula (3) to obtain the XYZ winding torque current feedback value i q2 and the excitation current feedback value i d2 .

[0138]

[0139] The motor speed and angular position are collected. In the low modulation ratio area, the angular position compensation is not performed. The collected speed is sent to the speed loop for calculation to obtain the torque current setting. q2 and the excitation current feedback value i d2 The difference is sent to the current loop, and the three-phase modulation reference voltage U is obtained through the current loop operation. d2 U q2 The reference voltage is sent to the three-phase space vector pulse width modulation to calculate the specific driving information of each power module, and the wave is completed. In addition, the three-phase winding ABC drive signal is set low to seal the power module.

[0140] Step 2: Switching controller for bus voltage U dc Sampling is performed and the modulus of the minimum sampling vector is calculated according to formula (4).

[0141]

[0142] Where U Min is the minimum sampling vector; T Min is the minimum sampling time.

[0143] According to the quadrature axis voltage u output by the XYZ current loop q2 With direct axis voltage u d2 Calculate the XYZ reference voltage modulus |u ref-XYZ |

[0144]

[0145] The switching state is judged according to formula (6). When formula (6) is satisfied, the state variable Mode=0, the system continues to operate in the low modulation ratio area, and enters step 1 to complete the XYZ three-phase winding drive.

[0146] |u ref-XYZ |≤2.1|U Min | (6)

[0147] When equation (6) is not satisfied, the state variable Mode=1 and the system enters the normal modulation area and proceeds to step 3.

[0148] In this implementation, the motor speed is set to 40r / min (0.32pu), the load torque is 110N·m, and the DC bus voltage is 550V. At this time, the reference voltage amplitude of the XYZ three-phase winding is 55V, the minimum sampling time is 2us, and the switching period corresponds to a 25kHz switching frequency of 40us. The minimum sampling vector is:

[0149]

[0150] In each switching cycle, the minimum sampling vector and the XYZ reference voltage are substituted into equation (6) to judge the switching state:

[0151] |u ref-XYZ |=55≤2.1|U Min |=2.1×37=74

[0152] In this state, the switching condition is not met, so the state variable Mode = 0. The system maintains operation in the low modulation ratio area and adopts a single three-phase winding operation drive scheme.

[0153] The motor suddenly increases from the low modulation operation area of ​​40r / min (0.32pu) speed and 110N·m load to the normal modulation ratio operation area of ​​125r / min (1p.u) speed and 1069N·m load. At this time, equation (6) is no longer satisfied, so the state variable system enters the normal modulation ratio area. At this time, the drive scheme of two sets of three-phase windings is adopted, and RHPWM is used for modulation.

[0154] in accordance with Figure 1 , reorganize the control system according to the state variable Mode=1.

[0155] Step 3: In the normal modulation ratio area, the two sets of three-phase windings work together to shift the carrier of the three-phase winding XYZ by 0.25T. s ;

[0156] When S A =0, S B =0, S C =0 or S X =0, S Y =0, S Z =0 when the corresponding voltage vector U 0 ;

[0157] When S A =1, S B =0, S C =0 or S X =1, S Y =0, S Z =0 when the corresponding voltage vector U 1 ;

[0158] When S A =1, S B =1, S C =0 or S X =1, S Y =1, S Z =0 when the corresponding voltage vector U 2 ;

[0159] When S A =0, S B =1, S C =0 or S X =0, S Y =1, S Z =0 when the corresponding voltage vector U 3 ;

[0160] When S A =0, S B =1, S C =1 or S X =0, S Y =1, S Z =1 corresponds to the voltage vector U 4 ;

[0161] When S A =0, S B =0, S C =1 or S X =0, S Y=0, S Z =1 corresponds to the voltage vector U 5 ;

[0162] When S A =1, S B =0, S C =1 or S X =1, S Y =0, S Z =1 corresponds to the voltage vector U 6 ;

[0163] When S A =1, S B =1, S C =1 or S X =1, S Y =1, S Z =1 corresponds to the voltage vector U 7 ;

[0164] Voltage vector U 1 With voltage vector U 2 The area enclosed in space is sector I;

[0165] Voltage vector U 2 With voltage vector U 3 The area enclosed in space is sector II;

[0166] Voltage vector U 3 With voltage vector U 4 The area enclosed in space is sector III;

[0167] Voltage vector U 4 With voltage vector U 5 The area enclosed in space is sector IV;

[0168] Voltage vector U 5 With voltage vector U 6 The area enclosed in space is sector V;

[0169] Voltage vector U 6 With voltage vector U 1 The area enclosed in space is sector VI;

[0170] Take the midline of sectors I to VI respectively, and the area surrounded by the midline of sector I and the midline of sector VI is the normal modulation ratio area G1;

[0171] The area surrounded by the midline of sector II and the midline of sector I is the normal modulation ratio area G2;

[0172] The area surrounded by the midline of sector II and the midline of sector III is the modulation ratio normal area G3;

[0173] The area surrounded by the midline of sector III and the midline of sector IV is the modulation ratio normal area G4;

[0174] The area surrounded by the midline of sector IV and the midline of sector V is the modulation ratio normal area G5;

[0175] The area surrounded by the midline of sector V and the midline of sector VI is the modulation ratio normal area G6;

[0176] Among them, the modulation ratio normal area G1 and the modulation ratio normal area G4 are zero vector modification areas, the modulation ratio normal area G1 includes the modulation ratio normal area G1-Ⅰ and the modulation ratio normal area G1-Ⅱ, the dividing line of sector VI and the voltage vector U 1 The area surrounded by the modulation ratio is the normal area G1-Ⅰ, the center line of sector Ⅰ and the voltage vector U 1 The enclosed area is the modulation ratio normal area G1-Ⅱ;

[0177] The modulation ratio normal region G4 includes the modulation ratio normal region G4-I and the modulation ratio normal region G4-II. The center line of sector III and the voltage vector U 4 The area surrounded by the modulation ratio is the normal area G4-Ⅰ, the center line of sector Ⅳ and the voltage vector U 4 The enclosed area is the modulation ratio normal area G4-Ⅱ;

[0178] A single current sensor is used to sample the sum of the current between the upper bridge arms of the X and Y phases in the three-phase winding XYZ and the current between the lower bridge arms of the A and B phases in the three-phase winding ABC at different sampling vector combinations, and the six-phase current reconstruction is completed according to the six-phase current reconstruction expression in the normal modulation ratio area.

[0179] When the reference voltage vector is located at G1-Ⅰ, the switching vector combination ABC-U 2 XYZ-U 1 ,ABC-U 5 XYZ-U 1 ,ABC-U 1 XYZ-U 2 ,ABC-U 1 XYZ-U 5 Sampling is performed at the sampling current I 1 I 2 I 3 I 4 .

[0180] When the reference voltage vector is located at G1-II, the switching vector combination ABC-U6 XYZ-U 1 ,ABC-U 3 XYZ-U 1 ,ABC-U 1 XYZ-U 6 ,ABC-U 1 XYZ-U 3 Sampling is performed at the sampling current I 1 I 2 I 3 I 4 .

[0181] When the reference voltage vector is located at G2, the switching vector combination ABC-U 0 XYZ-U 2 ,ABC-U 7 XYZ-U 2 ,ABC-U 2 XYZ-U 0 ,ABC-U 2 XYZ-U 7 Sampling is performed at the sampling current I 1 I 2 I 3 I 4 .

[0182] When the reference voltage vector is located at G3, the switching vector combination ABC-U 0 XYZ-U 3 ,ABC-U 7 XYZ-U 3 ,ABC-U 3 XYZ-U 0 ,ABC-U 3 XYZ-U 7 Sampling is performed at the sampling current I 1 I 2 I 3 I 4 .

[0183] When the reference voltage vector is located at G4-Ⅰ, the switching vector combination ABC-U 2 XYZ-U 4 ,ABC-U 5 XYZ-U 4 ,ABC-U 4 XYZ-U 2 ,ABC-U 4 XYZ-U 5 Sampling is performed at the sampling current I 1 I 2 I 3 I4 .

[0184] When the reference voltage vector is located at G4-II, the switching vector combination ABC-U 2 XYZ-U 1 ,ABC-U 5 XYZ-U 1 ,ABC-U 1 XYZ-U 2 ,ABC-U 1 XYZ-U 5 Sampling is performed at the sampling current I 1 I 2 I 3 I 4 .

[0185] When the reference voltage vector is located at G5, the switching vector combination ABC-U 0 XYZ-U 5 ,ABC-U 7 XYZ-U 5 ,ABC-U 5 XYZ-U 0 ,ABC-U 5 XYZ-U 7 Sampling is performed at the sampling current I 1 I 2 I 3 I 4 .

[0186] When the reference voltage vector is located at G6, the switching vector combination ABC-U 0 XYZ-U 6 ,ABC-U 7 XYZ-U 6 ,ABC-U 6 XYZ-U 0 ,ABC-U 6 XYZ-U 7 Sampling is performed at the sampling current I 1 I 2 I 3 I 4 .

[0187] According to the operating voltage vectors of the two sets of three-phase windings at the sampling point, the corresponding relationship between the sampled current and the phase current is obtained by querying Table 2. Combined with the current constraint relationship (7), the six-phase current reconstruction expression can be solved.

[0188]

[0189] Table 2 Correspondence between current sensor sampling results and phase current under different voltage vectors

[0190] <![CDATA[U i ]]> <![CDATA[U 0 ]]> <![CDATA[U 7 ]]> <![CDATA[U 1 ]]> <![CDATA[U 2 ]]> <![CDATA[U 3 ]]> <![CDATA[U 4 ]]> <![CDATA[U 5 ]]> <![CDATA[U 6 ]]> Isum-ABC <![CDATA[-i A ]]> 0 <![CDATA[-i A ]]> <![CDATA[i C ]]> <![CDATA[i C ]]> 0 <![CDATA[i B ]]> <![CDATA[i B ]]> Isum-XYZ 0 <![CDATA[-i X ]]> 0 <![CDATA[i Y ]]> <![CDATA[i Y ]]> <![CDATA[-i X ]]> <![CDATA[i Z ]]> <![CDATA[i Z ]]>

[0191] According to the normal modulation ratio area of ​​the reference voltage, sampling is performed in the corresponding vector combination to obtain the sampling current I 1 I 2 I 3 I 4 .

[0192] In this embodiment, taking the modulation ratio normal region G1-I as an example, in the switching vector combination three-phase winding ABC voltage vector U 2 With XYZ voltage vector U 1 During the overlapping time period, sampling is performed to obtain the sampling current I 1 In the switching vector combination three-phase winding ABC voltage vector U 5 With XYZ voltage vector U 1 During the overlapping time period, sampling is performed to obtain the sampling current I 2 In the switching vector combination three-phase winding ABC voltage vector U 1 With XYZ voltage vector U 2 During the overlapping time period, sampling is performed to obtain the sampling current I 3 In the switching vector combination three-phase winding ABC voltage vector U 1 With XYZ voltage vector U 5 During the overlapping time period, sampling is performed to obtain the sampling current I 4 .

[0193] According to the operating voltage vectors of the two sets of three-phase windings at the sampling point, the corresponding relationship between the sampling current and the phase current is obtained by querying Table 2, and the phase current matrix is ​​solved to complete the six-phase current reconstruction. Take the modulation ratio normal area G1-Ⅰ as an example:

[0194] The voltage vector U in the three-phase winding ABC 2 The three-phase winding XYZ voltage vector U 1 The sampled current I obtained by sampling during the overlapping time period 1 , we can know from Table 2 that the voltage vector U of the three-phase winding ABC is 2 The current formed in the current sensor is i C , three-phase winding XYZ voltage vector U 1 In the current sensor, 0, the two are superimposed and it can be seen that the sampling current i C +0.

[0195] The voltage vector U in the three-phase winding ABC 5 The three-phase winding XYZ voltage vector U 1 The sampled current I obtained by sampling during the overlapping time period 2, we can know from Table 2 that the voltage vector U of the three-phase winding ABC is 5 The current formed in the current sensor is i B , three-phase winding XYZ voltage vector U 1 In the current sensor, 0, the two are superimposed and it can be seen that the sampling current i B +0.

[0196] The voltage vector U in the three-phase winding ABC 1 The three-phase winding XYZ voltage vector U 2 The sampled current I obtained by sampling during the overlapping time period 3 , we can know from Table 2 that the voltage vector U of the three-phase winding ABC is 1 The current formed in the current sensor is -i A , three-phase winding XYZ voltage vector U 2 In the current sensor i Y , the two are superimposed and it can be seen that the sampling current -i A +i Y .

[0197] The voltage vector U in the three-phase winding ABC 1 The three-phase winding XYZ voltage vector U 5 The sampled current I obtained by sampling during the overlapping time period 4 , we can know from Table 2 that the voltage vector U of the three-phase winding ABC is 1 The current formed in the current sensor is -i A , three-phase winding XYZ voltage vector U 5 In the current sensor i Z , the two are superimposed and it can be seen that the sampling current -i A +i Z .

[0198] Therefore, the corresponding relationship between the sampling current and the phase current is:

[0199]

[0200] In combination with the current constraint equation (7), the following corresponding relationship can be obtained:

[0201]

[0202] By inverting equation (9), we can get the current reconstruction expression at this time:

[0203]

[0204] According to the above solution process, the current reconstruction expressions of different reconstruction groups are summarized in Table 3;

[0205] Table 3 Current sensor sampling results and current reconstruction expressions of different reconstruction groups

[0206]

[0207]

[0208]

[0209] In the normal modulation area, hybrid pulse width modulation RHPWM is used, and RHPWM is:

[0210] In the modulation ratio normal area G1-Ⅰ and G4-Ⅰ, dynamic zero state PWM is applied to set the zero vector U 0 , U 7 Replaced by the opposite effective vector U 2 , U 5 ; In the modulation ratio normal area G1-Ⅱ and G4-Ⅱ, dynamic zero state PWM is applied to zero vector U 0 , U 7 Replaced by the opposite effective vector U 6 , U 3 .

[0211] In the normal modulation ratio area G2, G3, G5, and G6, SVPWM is used for modulation.

[0212] The sampling angle is used for compensation. In actual work, the motor estimates that the direct-axis voltage is close to zero. The actual direct-axis voltage is filtered to obtain the filtered direct-axis voltage. The sum of the two sets of actual direct-axis voltages after filtering is used as the basis for resolver compensation. According to its size, the position compensation angle is adjusted to minimize the actual direct-axis voltage. In the normal modulation ratio area, the angle obtained by sampling the motor resolver is compensated.

[0213] According to the direct-axis voltage equation in the dual dq coordinate system of formula (11), combined with the current DTP-PMSM operating conditions, the output back electromotive force of the current loop controller on the d-axis is estimated.

[0214]

[0215] Where: is the theoretical estimated value of the direct-axis voltage of the three-phase winding ABC; is the direct-axis voltage of the three-phase winding XYZ; i d1 is the theoretical estimated value of the direct-axis current of the three-phase winding ABC; i d2 is the direct axis current of the three-phase winding XYZ; L d is the direct axis inductance of the rotating coordinate system; L q is the quadrature axis inductance of the rotating coordinate system; L m is the stator excitation inductance; ω is the electrical angle; R s is the stator resistance.

[0216] The actual direct axis voltage u d1 、u d2 Perform filtering to prevent excessive jitter during parameter debugging and obtain the filtered voltage u d1-LPF 、u d2-LPF .

[0217] The voltage error is obtained by subtracting the theoretical estimated value of the direct axis voltage from the filtered value using equation (12):

[0218]

[0219] The equation (13) is used to sum the direct-axis voltage errors of the two sets of three-phase windings as the basis for resolver compensation.

[0220] u d-error =|u d1-error +u d2-error | (13)

[0221] According to the size of the d-axis back electromotive force, the position compensation angle is adjusted to make the error and u d-error When the minimum value is reached, the machine stops and saves the position angle θ after compensation. According to the position angle θ, the sampling speed ω after resolver compensation is obtained. m .

[0222] The reconstructed current is substituted into equation (12) in units of three phases to complete the Clark-Park transformation, and two sets of torque current feedback values ​​i are obtained respectively. q1 i q2 and the excitation current feedback value i d1 i d2 ;

[0223] Sampling speed ω m The torque current is given by the speed loop. The torque current given by the two sets of three-phase windings is equal, and the six-phase current coordinate transformation is reconstructed to obtain the AC and DC axis current feedback i d1 i q1 i d2 i q2 Combined with the torque given current, the current loop operation is performed to obtain the six-phase modulation reference voltage U d1 U q1 U d2 U q2 At the same time, in order to prevent the given voltage from being less than the minimum sampling vector in the transient transition, the minimum sampling voltage vector 37V is used to limit the lower limit of the output reference quadrature axis voltage. The reference voltage is sent to the six-phase modulation to complete the power module drive.

[0224] The limiting formula is as follows (14):

[0225]

[0226] At this time, the switching state is judged according to formula (15). When formula (15) is satisfied, the state variable Mode=1 and the system continues to operate in the normal modulation ratio area to complete the driving of two sets of three-phase windings.

[0227] |u ref-XYZ |≤1.1|U Min | (15)

[0228] When equation (15) is not satisfied, the system re-enters the low modulation ratio region and proceeds to step 1.

[0229] The system works at the rated working condition with a reference voltage of 183V, and equation (15) is not satisfied, so the state variable maintains Mode = 1, the system maintains normal modulation area operation, and adopts a driving scheme of two sets of three-phase windings working together. When equation (15) is satisfied again, the system will re-enter the state of single three-phase winding operation, and initialize the parameters of the loop corresponding to XYZ.

[0230] Figure 8(a) to Figure 8(c) The waveforms of the ABC three-phase actual current, ABC three-phase reconstructed current, XYZ three-phase actual current, and XYZ three-phase reconstructed current are given in the dynamic switching process. Figure 8(a) to Figure 8(c) It can be seen that the method proposed in the present invention effectively eliminates the low modulation ratio reconstruction blind area. In the entire dynamic process, the three-phase reconstructed current of the DTP-PMSM can smoothly transition from the low modulation ratio area to the normal modulation ratio area. And the X-phase current reconstruction current follows the measured current very well.

[0231] Since the reconstruction method of the present invention only involves the low modulation ratio current reconstruction method, reconstruction topology, and switching control method, this implementation has no constraints on the controller, DTP-PMSM phase angle, etc. This implementation is also applicable to applications where the 30° phase shift angle DTP-PMSM speed loop controller uses an auto-disturbance rejection controller, and the current loop controller uses a proportional resonant controller.

[0232] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A dual three-phase permanent magnet synchronous motor switching control method based on single current sensor sampling, characterized in that: The method comprises: Step 1: In the low modulation ratio area, the three-phase winding XYZ operates independently, the three-phase winding ABC is subjected to wave sealing processing, a single current sensor is used to sample the current between the upper bridge arms of the X and Y phases in the three-phase winding XYZ, and the low modulation ratio three-phase current reconstruction is completed according to the three-phase current reconstruction expression in the low modulation ratio area; the reconstructed three-phase current and the sampled speed are sent into the loop for calculation to obtain the three-phase modulation reference voltage, and the power module is driven by low modulation ratio mixed pulse width modulation; Step 2: Calculate the minimum sampling vector |U according to the minimum sampling time Min |, determine the reference voltage modulus value of the three-phase winding XYX|u ref-XYZ |Is it satisfied? |u ref-XYZ |≤2.1|U Min |, if yes, return to step 1, if no, go to step 3; Step 3, in the normal modulation ratio area, the two sets of three-phase windings are operated in coordination, and a single current sensor is used to sample the sum of the current between the upper bridge arms of the X and Y phases in the three-phase winding XYZ and the current between the lower bridge arms of the A and B phases in the three-phase winding ABC at different sampling vector combinations, and the six-phase current reconstruction is completed according to the six-phase current reconstruction expression in the normal modulation ratio area, and the reconstructed six-phase current and the sampling speed are sent into the loop for calculation to obtain the modulation reference voltage, and the modulation reference voltage of the quadrature axis is limited, and then all the modulation reference voltages are subjected to hybrid pulse width modulation RHPWM to complete the power module drive; Step 4: Determine the reference voltage modulus of the three-phase winding XYZ |u ref-XYZ |Is it satisfied? |u ref-XYZ |≤1.1|U Min |, if yes, go to step 1, if no, go to step 3.

2. The dual three-phase permanent magnet synchronous motor switching control method according to claim 1, characterized in that: The method for obtaining the three-phase current reconstruction expression in the low modulation ratio area includes: S A , S B , S C , S X , S Y , S Z They are the six-phase bridge arm switching functions of the dual three-phase permanent magnet synchronous motor, a value of 0 represents the lower bridge arm is turned on, and a value of 1 represents the upper bridge arm is turned on; When S A =0, S B =0, S C =0 or S X =0, S Y =0, S Z =0 corresponds to voltage vector U0; When S A =1, S B =0, S C =0 or S X =1, S Y =0, S Z =0 corresponds to voltage vector U1; When S A =1, S B =1, S C =0 or S X =1, S Y =1, S Z =0 corresponds to voltage vector U2; When S A =0, S B =1, S C =0 or S X =0, S Y =1, S Z =0 corresponds to voltage vector U3; When S A =0, S B =1, S C =1 or S X =0, S Y =1, S Z =1 corresponds to voltage vector U4; When S A =0, S B =0, S C =1 or S X =0, S Y =0, S Z =1 corresponds to voltage vector U5; When S A =1, S B =0, S C =1 or S X =1, S Y =0, S Z =1 corresponds to voltage vector U6; When S A =1, S B =1, S C =1 or S X =1, S Y =1, S Z =1 corresponds to voltage vector U7; The area enclosed by the voltage vector U1 and the voltage vector U2 in space is the low modulation ratio reconstruction area L1; The area surrounded by the voltage vector U2 and the voltage vector U3 in space is the low modulation ratio reconstruction area L2; The area surrounded by the voltage vector U3 and the voltage vector U4 in space is the low modulation ratio reconstruction area L3; The area surrounded by the voltage vector U4 and the voltage vector U5 in space is the low modulation ratio reconstruction area L4; The area surrounded by the voltage vector U5 and the voltage vector U6 in space is the low modulation ratio reconstruction area L5; The area surrounded by the voltage vector U6 and the voltage vector U1 in space is the low modulation ratio reconstruction area L6; According to the different low modulation ratio reconstruction regions where the reference voltage is located, the three-phase current reconstruction expression is determined: Among them, 0T s , 0.5T s Represents a switching cycle T s Two sampling moments within ; i X Indicates the current of phase X in the three-phase winding XYZ; i Y Indicates the current of phase Y in three-phase winding XYZ i Z Represents the current of phase Z in the three-phase winding XYZ.

3. The dual three-phase permanent magnet synchronous motor switching control method according to claim 2 is characterized in that: Low modulation ratio hybrid pulse width modulation includes: When the reference voltage vector is located in the low modulation ratio reconstruction area L1 or L4, the voltage vectors U0 and U7 of the three-phase winding XYZ are replaced by the voltage vectors U6 and U3 respectively; When the reference voltage vector is located in the low modulation ratio reconstruction region L2, the voltage vectors U0 and U7 of the three-phase winding XYZ are replaced by the voltage vectors U5 and U2 respectively; When the reference voltage vector is located in the low modulation ratio reconstruction area L3 or L6, the voltage vectors U0 and U7 of the three-phase winding XYZ are replaced by the voltage vectors U2 and U5 respectively; When the reference voltage vector is located in the low modulation ratio reconstruction region L5, the voltage vectors U0 and U7 of the three-phase winding XYZ are replaced by voltage vectors U3 and U6 respectively.

4. The dual three-phase permanent magnet synchronous motor switching control method according to claim 1, characterized in that: The method for obtaining the six-phase current reconstruction expression in the modulation ratio normal area includes: S A , S B , S C , S X , S Y , S Z They are the six-phase bridge arm switching functions of the dual three-phase permanent magnet synchronous motor, a value of 0 represents the lower bridge arm is turned on, and a value of 1 represents the upper bridge arm is turned on; When S A =0, S B =0, S C =0 or S X =0, S Y =0, S Z =0 corresponds to voltage vector U0; When S A =1, S B =0, S C =0 or S X =1, S Y =0, S Z =0 corresponds to voltage vector U1; When S A =1, S B =1, S C =0 or S X =1, S Y =1, S Z =0 corresponds to voltage vector U2; When S A =0, S B =1, S C =0 or S X =0, S Y =1, S Z =0 corresponds to voltage vector U3; When S A =0, S B =1, S C =1 or S X =0, S Y =1, S Z =1 corresponds to voltage vector U4; When S A =0, S B =0, S C =1 or S X =0, S Y =0, S Z =1 corresponds to voltage vector U5; When S A =1, S B =0, S C =1 or S X =1, S Y =0, S Z =1 corresponds to voltage vector U6; When S A =1, S B =1, S C =1 or S X =1, S Y =1, S Z =1 corresponds to voltage vector U7; The area enclosed by the voltage vector U1 and the voltage vector U2 in space is sector I; The area enclosed by the voltage vector U2 and the voltage vector U3 in space is sector II; The area enclosed by the voltage vector U3 and the voltage vector U4 in space is sector III; The area enclosed by the voltage vector U4 and the voltage vector U5 in space is sector IV; The area enclosed by the voltage vector U5 and the voltage vector U6 in space is sector V; The area enclosed by the voltage vector U6 and the voltage vector U1 in space is sector VI; Take the midline of sectors I to VI respectively, and the area surrounded by the midline of sector I and the midline of sector VI is the normal modulation ratio area G1; The area surrounded by the midline of sector II and the midline of sector I is the normal modulation ratio area G2; The area surrounded by the midline of sector II and the midline of sector III is the modulation ratio normal area G3; The area surrounded by the midline of sector III and the midline of sector IV is the modulation ratio normal area G4; The area surrounded by the midline of sector IV and the midline of sector V is the modulation ratio normal area G5; The area surrounded by the midline of sector V and the midline of sector VI is the normal modulation ratio area G6; Among them, the normal modulation ratio region G1 and the normal modulation ratio region G4 are zero vector modification regions, the normal modulation ratio region G1 includes the normal modulation ratio region G1-Ⅰ and the normal modulation ratio region G1-Ⅱ, the region surrounded by the middle dividing line of sector VI and the voltage vector U1 is the normal modulation ratio region G1-Ⅰ, and the region surrounded by the middle dividing line of sector Ⅰ and the voltage vector U1 is the normal modulation ratio region G1-Ⅱ; The normal modulation ratio region G4 includes the normal modulation ratio region G4-Ⅰ and the normal modulation ratio region G4-Ⅱ. The region surrounded by the middle dividing line of the sector III and the voltage vector U4 is the normal modulation ratio region G4-Ⅰ, and the region surrounded by the middle dividing line of the sector IV and the voltage vector U4 is the normal modulation ratio region G4-Ⅱ. The six-phase current reconstruction expression in the normal modulation area is: Among them, ABC-U i XYZ-U j Represents the switching period T s The voltage vector corresponding to the inner three-phase winding ABC is U i , the voltage vector corresponding to the three-phase winding XYZ is U j , i=0,1,2,3,4,5,6,7, j=0,1,2,3,4,5,6,7; I1, I2, I3, and I4 represent the currents sampled by the four sampling vector combinations; i X Represents the current of phase X in the three-phase winding XYZ; i Y Represents the current of phase Y in the three-phase winding XYZ; i Z Represents the current of phase Z in the three-phase winding XYZ; i A Represents the current of phase A in the three-phase winding ABC; i B Represents the current of phase B in three-phase winding ABC; i C Represents the current of phase C in the three-phase winding ABC.

5. The dual three-phase permanent magnet synchronous motor switching control method according to claim 1, characterized in that: Hybrid pulse width modulation RHPWM includes: Shift the carrier of three-phase winding XYZ by 0.25T s , in the modulation ratio normal region G1-Ⅰ and the modulation ratio normal region G4-Ⅰ, dynamic zero-state PWM modulation is applied to replace the voltage vectors U0 and U7 with the voltage vectors U2 and U5 respectively; In the modulation ratio normal region G1-Ⅱ and the modulation ratio normal region G4-Ⅱ, dynamic zero-state PWM modulation is applied to replace the voltage vectors U0 and U7 with the voltage vectors U6 and U3 respectively; In the normal modulation ratio area G2, G3, G5, and G6, SVPWM is used for modulation.

6. The dual three-phase permanent magnet synchronous motor switching control method according to claim 1, characterized in that: Limit the modulation reference voltage of the quadrature axis: U q is the modulation reference voltage of the quadrature axis, T s represents the switching period, T min Indicates the minimum sampling time, U dc Indicates the bus voltage.

7. The dual three-phase permanent magnet synchronous motor switching control method according to claim 1, characterized in that: When the modulation ratio is in the normal region, the method for acquiring the sampling speed includes: The theoretical estimate of the direct-axis voltage output by the current loop controller ACR-PI is: Where: is the theoretical estimated value of the direct-axis voltage of the first set of three-phase windings; is the direct-axis voltage of the second three-phase winding; i d1 is the theoretical estimated value of the direct-axis current of the first three-phase winding; i d2 is the direct-axis current of the second three-phase winding; i q1 is the theoretical estimated value of the first set of three-phase winding quadrature-axis current; i q2 is the quadrature-axis current of the second three-phase winding; L d is the direct axis inductance of the rotating coordinate system; L q is the quadrature axis inductance of the rotating coordinate system; L m is the stator excitation inductance; ω is the electrical angle; R s is the stator resistance; For a given value of flux voltage u d1 、u d2 Filter and get the filtered voltage u d1-LPF 、u d2-LPF ; The voltage error is obtained: Sum the direct-axis voltage errors of the two sets of three-phase windings to obtain u d-error , as the basis for resolver compensation: in d-error =|in d1-error +in d2-error | According to the magnitude of the direct-axis voltage, the initial position angle θ0 of the motor is compensated by a resolver to make the error and u d-error When the minimum value is reached, the position angle θ after compensation is saved, and the sampling speed ω after resolver compensation is obtained according to the position angle θ. m .

8. A computer-readable storage device storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the dual three-phase permanent magnet synchronous motor switching control method as claimed in any one of claims 1 to 7 are implemented.

9. A dual three-phase permanent magnet synchronous motor switching control device, comprising a storage device, a processor, and a computer program stored in the storage device and executable on the processor, characterized in that: The processor executes the computer program to implement the steps of the dual three-phase permanent magnet synchronous motor switching control method according to any one of claims 1 to 7.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the dual three-phase permanent magnet synchronous motor switching control method as claimed in any one of claims 1 to 7 are implemented.

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