Switching control method for dual three-phase permanent magnet synchronous motor based on single current sensor sampling

Abstract

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

Description

Technical Field

[0001] This invention relates to a switching control method for a dual three-phase permanent magnet synchronous motor based on sampling by a single current sensor, belonging to the field of motor drive. Background Technology

[0002] High-power permanent magnet synchronous motors (PMSMs) are widely used in ship propulsion, vehicle drive, aerospace, and wind power generation due to their advantages such as high power density, high operating efficiency, high control precision, and low operating noise. However, facing increasingly complex operating conditions and specific application environments, traditional motor designs can no longer meet 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. The transformation from three-phase PMSMs to dual three-phase permanent magnet synchronous motors (DTP-PMSMs) is a prime example of this process.

[0003] To achieve precise control of a DTP-PMSM, six-phase current information needs to be acquired. Traditional methods for acquiring phase current information typically involve inserting current sensors between corresponding phase lines. However, this approach increases hardware costs, the size of the driver itself, and the complexity of the hardware structure. To reduce hardware costs and improve system reliability, researchers have begun exploring the use of a single current sensor to reconstruct the phase currents of a multi-phase motor.

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

[0005] When different methods are used in DTP-PMSM vector control frequency converter systems to eliminate the current reconfiguration blind zone under different modulation ratios, a clear and efficient switching control method is needed for different reconfiguration schemes. The switching of current reconfiguration schemes under different modulation ratios may lead to difficulties in reconfiguring phase currents over a wide modulation ratio range, and there is room for further optimization.

[0006] In the normal modulation range of actual motor drive systems, the delay characteristics of the motor rotation position acquisition system cause deviations in the position information used for transformation in the control loop, leading to increased reactive voltage and increased current under the same torque output. Ultimately, this affects the maximum torque-to-current ratio output. To address this, scholars have proposed various compensation methods. However, the vertical or horizontal deviations in the winding positions of the two sets of three-phase windings in actual DTP-PMSM systems present new challenges to the delay compensation of DTP-PMSM resolvers. Summary of the Invention

[0007] To address the problem of difficult phase current reconstruction during transient switching in dual three-phase permanent magnet synchronous motors when switching between the low modulation ratio region and the normal region of current reconstruction using a single current sensor, this invention provides a switching control method for dual three-phase permanent magnet synchronous motors.

[0008] The present invention provides a switching control method for a dual three-phase permanent magnet synchronous motor based on sampling by a single current sensor, comprising:

[0009] Step 1: In the low modulation ratio region, the three-phase windings XYZ operate independently. The three-phase windings ABC are subjected to wave blocking. 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 windings XYZ. The low modulation ratio three-phase current reconstruction is completed according to the three-phase current reconstruction expression in the low modulation ratio region. The reconstructed three-phase current and the sampled speed are sent into the loop for calculation to obtain the three-phase modulation reference voltage. After low modulation ratio mixed pulse width modulation, the power module drive is completed.

[0010] Step 2: Calculate the minimum sampling vector |U| based on the minimum sampling time. Min | Determine the reference voltage magnitude of the three-phase winding XYX|u ref-XYZ |Does it satisfy|u ref-XYZ |≤2.1|U Min If yes, return to step 1; otherwise, proceed to step 3.

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

[0012] Step 4: Determine the reference voltage magnitude |u of the three-phase winding XYZ ref-XYZ |Does it satisfy|u ref-XYZ |≤1.1|UMin If yes, proceed to step 1; otherwise, proceed to step 3.

[0013] As a preferred method, the method for obtaining the three-phase current reconstruction expression in the low modulation ratio region includes:

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

[0015] When S A =0, S B =0, S C =0 or S X =0, S Y =0, S Z When = 0, the corresponding voltage vector is U0;

[0016] When S A =1, S B =0, S C =0 or S X =1, S Y =0, S Z When = 0, the corresponding voltage vector is U1;

[0017] When S A =1, S B =1, S C =0 or S X =1, S Y =1, S Z =0 corresponds to the voltage vector U2;

[0018] When S A =0, S B =1, S C =0 or S X =0, S Y =1, S Z When = 0, the corresponding voltage vector is U3;

[0019] When S A =0, S B =1, S C =1 or S X =0, S Y =1, S Z When = 1, the corresponding voltage vector is U4;

[0020] When S A =0, S B =0, SC =1 or S X =0, S Y =0, S Z When = 1, the corresponding voltage vector is U5;

[0021] When S A =1, S B =0, S C =1 or S X =1, S Y =0, S Z When = 1, the corresponding voltage vector is U6;

[0022] When S A =1, S B =1, S C =1 or S X =1, S Y =1, S Z When = 1, the corresponding voltage vector is U7;

[0023] The region enclosed in space by voltage vectors U1 and U2 is the low modulation ratio reconstruction region L1;

[0024] The region enclosed in space by voltage vectors U2 and U3 is the low modulation ratio reconstruction region L2;

[0025] The region enclosed in space by voltage vectors U3 and U4 is the low modulation ratio reconstruction region L3;

[0026] The region enclosed in space by voltage vectors U4 and U5 is the low modulation ratio reconstruction region L4;

[0027] The region enclosed in space by voltage vectors U5 and U6 is the low modulation ratio reconstruction region L5;

[0028] The region enclosed in space by voltage vectors U6 and U1 is the low modulation ratio reconstruction region L6;

[0029] Based on the different low modulation ratio reconstruction regions where the reference voltage is located, the three-phase current reconstruction expression is determined as follows:

[0030]

[0031] Among them, 0T s 0.5T s T represents one switching cycle. s Two sampling times within;

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

[0033] iY This represents the current in the Y phase of the three-phase winding XYZ.

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

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

[0036] When the reference voltage vector is located in the low modulation ratio reconstruction region L1 or L4, the voltage vectors U0 and U7 of the three-phase winding XYZ are replaced with voltage vectors U6 and U3, respectively.

[0037] 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 windings XYZ are replaced with voltage vectors U5 and U2, respectively.

[0038] When the reference voltage vector is located in the low modulation ratio reconstruction region L3 or L6, the voltage vectors U0 and U7 of the three-phase winding XYZ are replaced with voltage vectors U2 and U5, respectively.

[0039] 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 windings XYZ are replaced with voltage vectors U3 and U6, respectively.

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

[0041] S A S B S C S X S Y S Z These are the six-phase bridge arm switching functions for a dual three-phase permanent magnet synchronous motor. A value of 0 indicates that the lower bridge arm is on, and a value of 1 indicates that the upper bridge arm is on.

[0042] When S A =0, S B =0, S C =0 or S X =0, S Y =0, S Z When = 0, the corresponding voltage vector is U0;

[0043] When S A =1, S B =0, S C =0 or S X =1, S Y =0, S Z When = 0, the corresponding voltage vector is U1;

[0044] When S A =1, SB =1, S C =0 or S X =1, S Y =1, S Z =0 corresponds to the voltage vector U2;

[0045] When S A =0, S B =1, S C =0 or S X =0, S Y =1, S Z When = 0, the corresponding voltage vector is U3;

[0046] When S A =0, S B =1, S C =1 or S X =0, S Y =1, S Z When = 1, the corresponding voltage vector is U4;

[0047] When S A =0, S B =0, S C =1 or S X =0, S Y =0, S Z When = 1, the corresponding voltage vector is U5;

[0048] When S A =1, S B =0, S C =1 or S X =1, S Y =0, S Z When = 1, the corresponding voltage vector is U6;

[0049] When S A =1, S B =1, S C =1 or S X =1, S Y =1, S Z When = 1, the corresponding voltage vector is U7;

[0050] The region enclosed by voltage vectors U1 and U2 in space is sector I;

[0051] The region enclosed in space by voltage vectors U2 and U3 is sector II;

[0052] The region enclosed in space by voltage vectors U3 and U4 is sector III;

[0053] The region enclosed in space by voltage vectors U4 and U5 is sector IV;

[0054] The region enclosed in space by voltage vectors U5 and U6 is sector V;

[0055] The region enclosed in space by voltage vectors U6 and U1 is sector VI;

[0056] For sectors I to VI, take the midpoint line within each sector. The area enclosed by the midpoint line of sector I and the midpoint line of sector VI is the normal modulation ratio region G1.

[0057] The region enclosed by the midpoint line of sector II and the midpoint line of sector I is the normal modulation ratio region G2;

[0058] The region enclosed by the midpoint line of sector II and the midpoint line of sector III is the normal modulation ratio region G3;

[0059] The region enclosed by the midpoint line of sector III and the midpoint line of sector IV is the normal modulation ratio region G4;

[0060] The region enclosed by the midpoint line of sector IV and the midpoint line of sector V is the normal modulation ratio region G5;

[0061] The region enclosed by the midpoint of sector V and the midpoint of sector VI is the normal modulation ratio region G6;

[0062] 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 enclosed by the midpoint of sector VI and the voltage vector U1 is the normal modulation ratio region G1-Ⅰ, and the region enclosed by the midpoint of sector Ⅰ and the voltage vector U1 is the normal modulation ratio region G1-Ⅱ.

[0063] The normal modulation ratio region G4 includes the normal modulation ratio region G4-Ⅰ and the normal modulation ratio region G4-Ⅱ. The region enclosed by the midpoint line of sector Ⅲ and the voltage vector U4 is the normal modulation ratio region G4-Ⅰ, and the region enclosed by the midpoint line of sector Ⅳ and the voltage vector U4 is the normal modulation ratio region G4-Ⅱ.

[0064] The expression for the six-phase current reconstruction in the normal region with modulation ratio is:

[0065]

[0066]

[0067] Among them, ABC-U i XYZ-U j Indicates the switching period T s The voltage vector corresponding to the three-phase windings ABC is Ui 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] I1, I2, I3, and I4 represent the currents sampled by the combination of four sampling vectors; i X This represents the current in phase X of the three-phase winding XYZ; i Y This represents the current in the Y phase of a three-phase winding XYZ; i Z This represents the current in phase Z of the three-phase winding XYZ; i A This represents the current in phase A of the three-phase winding ABC; i B This represents the current in phase B of a three-phase winding ABC; i C This represents the current in phase C of the three-phase winding ABC.

[0069] Preferably, hybrid pulse width modulation (RHPWM) includes:

[0070] The carrier wave of the three-phase winding XYZ is shifted by 0.25T. s In the normal modulation ratio region G1-Ⅰ and the normal modulation ratio region G4-Ⅰ, dynamic zero-state PWM modulation is applied to replace voltage vectors U0 and U7 with voltage vectors U2 and U5, respectively.

[0071] In the normal modulation ratio region G1-Ⅱ and the normal modulation ratio region G4-Ⅱ, dynamic zero-state PWM modulation is applied to replace voltage vectors U0 and U7 with voltage vectors U6 and U3, respectively.

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

[0073] Preferably, the modulation reference voltage of the quadrature axis is limited:

[0074]

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

[0076] Preferably, in the modulation ratio normal region, the method for obtaining the sampling rotation speed includes:

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

[0078]

[0079] In the formula: This is the theoretical estimate of the direct-axis voltage of the first set of three-phase windings; For the direct-axis voltage of the second set of three-phase windings; i d1 This is the theoretical estimate of the direct-axis current of the first set of three-phase windings; i d2 For the direct-axis current of the second set of three-phase windings; i q1 This is the theoretical estimate of the quadrature axis current for the first set of three-phase windings; i q2 For the quadrature axis current of the second set of three-phase windings; L d For a rotating coordinate system, the inductance is a direct-axis inductance; L q For a rotating coordinate system, the quadrature-axis inductance is L; m R is the stator magnetizing inductance; ω is the electrical angle; s Stator resistance;

[0080] For the given value u of the flux linkage voltage d1 u d2 Filtering is performed to obtain the filtered voltage u. d1-LPF u d2-LPF ;

[0081] Voltage error obtained:

[0082]

[0083] Summing the direct-axis voltage errors of the two sets of three-phase windings yields u. d-error As a basis for resolver compensation:

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

[0085] Based on the magnitude of the direct-axis voltage, resolver compensation is applied to the initial position angle θ0 of the motor to balance the error and u. d-error Once the minimum value is reached, the compensated position angle θ is saved. Based on the position angle θ, the sampled rotational speed ω after resolver compensation is obtained. m .

[0086] The beneficial effects of this invention are as follows: Addressing the problem of difficult phase current reconstruction during transient switching transitions caused by the switching operation between the low modulation ratio region and the normal region of the single current sensor in a DTP-PMSM, this invention provides a switching control method under different modulation ratios, enabling phase current reconstruction over a wide modulation ratio range; this invention can achieve phase current reconstruction in the low modulation ratio region of a single current sensor in a DTP-PMSM drive system; and this invention provides a resolver delay compensation method tailored to the characteristics of DTP-PMSM. Attached Figure Description

[0087] Figure 1This is a switching control block diagram for a dual three-phase permanent magnet synchronous motor (DTP-PMSM), where θ0 is the electrical angle of the DTP-PMSM before compensation, θ is the electrical angle of the DTP-PMSM after compensation, ω is the electrical angular velocity of the DTP-PMSM, and I... SAMPLE The value is the current Hall sample value;

[0088] Figure 2 Flowchart of switching control for dual three-phase permanent magnet synchronous motors under different modulation ratios;

[0089] Figure 3 DTP-PMSM current reconfiguration topology;

[0090] Figure 4 This is the reconstruction region between low modulation ratio and normal modulation ratio;

[0091] Figure 5(a) shows the L1 carrier and PWM waveforms of the low modulation ratio reconfiguration region of the XYZ three-phase windings in the low modulation ratio region;

[0092] Figure 5(b) shows the L2 carrier and PWM waveforms of the low modulation ratio reconfiguration region of the XYZ three-phase windings in the low modulation ratio region;

[0093] Figure 5(c) shows the L3 carrier and PWM waveforms of the low modulation ratio reconfiguration region of the XYZ three-phase windings in the low modulation ratio region;

[0094] Figure 6 The waveforms of the sampled current and the actual XYZ phase current in the low modulation ratio region are shown.

[0095] Figure 7(a) shows the actual phase current waveforms in the XYZ region during the low modulation ratio.

[0096] Figure 7(b) shows the XYZ reconstructed phase current waveform in the low modulation ratio region;

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

[0098] Figure 8(a) shows the waveforms of the actual phase current and the reconstructed phase current of ABC when switching between different modulation ratio regions;

[0099] Figure 8(b) shows the waveforms of the actual phase current and the reconstructed phase current of XYZ when switching between different modulation ratio regions;

[0100] Figure 8(c) Errors between the actual X-phase current and the reconfiguration current during switching at different modulation ratios;

[0101] Figure 9(a) shows the actual XYZ phase current waveforms during motor startup in the low modulation ratio region;

[0102] Figure 9(b) shows the XYZ reconfiguration phase current waveforms during motor startup in the low modulation ratio region.

[0103] Figure 9(c) shows the error between the actual current and the reconfigured current of the X-phase motor during startup in the low modulation ratio region. Detailed Implementation

[0104] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0105] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0106] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

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

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

[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 These are the switching functions for the six-phase bridge arms, where a value of 0 indicates that the lower bridge arm is on, and a value of 1 indicates that the upper bridge arm is on; i A This represents the current in phase A of the three-phase winding ABC; i B This represents the current in phase B of a three-phase winding ABC; i C This represents the current in phase C of a three-phase winding ABC; i X This represents the current in phase X of the three-phase winding XYZ; i Y This represents the current in the Y phase of a three-phase winding XYZ; i Z I represents the current in phase Z of a three-phase winding XYZ; SAMPLE This is the sampled value from the current sensor.

[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 When = 0, the corresponding voltage vector is U0;

[0113] When S A =1, S B =0, S C =0 or S X =1, S Y =0, S Z When = 0, the corresponding voltage vector is U1;

[0114] When S A =1, S B =1, S C =0 or S X =1, S Y =1, S Z =0 corresponds to the voltage vector U2;

[0115] When S A =0, S B =1, S C =0 or S X =0, S Y =1, S Z When = 0, the corresponding voltage vector is U3;

[0116] When S A =0, S B =1, S C =1 or S X =0, S Y =1, S Z When = 1, the corresponding voltage vector is U4;

[0117] When S A =0, S B =0, S C =1 or S X =0, S Y =0, S Z When = 1, the corresponding voltage vector is U5;

[0118] When S A =1, S B =0, S C =1 or S X =1, S Y =0, S Z When = 1, the corresponding voltage vector is U6;

[0119] When S A =1, SB =1, S C =1 or S X =1, S Y =1, S Z When = 1, the corresponding voltage vector is U7;

[0120] The region enclosed in space by voltage vectors U1 and U2 is the low modulation ratio reconstruction region L1;

[0121] The region enclosed in space by voltage vectors U2 and U3 is the low modulation ratio reconstruction region L2;

[0122] The region enclosed in space by voltage vectors U3 and U4 is the low modulation ratio reconstruction region L3;

[0123] The region enclosed in space by voltage vectors U4 and U5 is the low modulation ratio reconstruction region L4;

[0124] The region enclosed in space by voltage vectors U5 and U6 is the low modulation ratio reconstruction region L5;

[0125] The region enclosed in space by voltage vectors U6 and U1 is the low modulation ratio reconstruction region L6;

[0126] When the motor operates in the low modulation ratio region, low modulation ratio hybrid pulse width modulation (LHPWM) is used for modulation. LHPWM involves blocking the three-phase windings ABC in the low modulation ratio region. When the reference voltage vector is located in the low modulation ratio reconstruction region L1 or L4, the zero vectors U0 and U7 of the XYZ phases are replaced with their opposite effective vectors U6 and U3, respectively. When the reference voltage vector is located in L2, the zero vectors U0 and U7 of the XYZ phases are replaced with their opposite effective vectors U5 and U2, respectively. When the reference voltage vector is located in the low modulation ratio reconstruction region L3 or L6, the zero vectors U0 and U7 of the XYZ phases are replaced with their opposite effective vectors U2 and U5, respectively. When the reference voltage vector is located in the low modulation ratio reconstruction region L5, the zero vectors U0 and U7 of the XYZ phases are replaced with their opposite effective vectors U3 and U6, respectively.

[0127] Samples are taken at the beginning (0Ts) and the midpoint (0.5Ts) of the switching period Ts to obtain the sampled 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 the low modulation ratio region.

[0129]

[0130] This implementation uses a 30-pole, rated speed of 125 rpm, motor flux linkage of 0.89 Wb, direct-axis and quadrature-axis inductance of 7.1 mH, and stator excitation inductance of 5.1 mH. A simulation experiment was conducted using a dual three-phase permanent magnet synchronous motor with a 0° phase shift angle, a switching frequency of 25 kHz, and two sets of three-phase windings connected in an independent star configuration. 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 command.

[0131] Start the motor at a set speed of 40 r / min (0.32 pu), according to Figure 2 As shown in the motor switching control flowchart, the motor initially operates in the low modulation ratio region upon startup. For example... Figure 1 The independent three-phase windings XYZ in the low modulation ratio region are operating, the torque current setpoint of ABC is 0, and the ABC drive is blocked.

[0132] LHPWM modulation is employed in the low modulation ratio region, replacing the zero vector with the opposite effective vector. Sampling is performed at the beginning (0Ts) and midpoint (0.5Ts) of the switching cycle Ts to obtain the sampled current I. L1 with I L2 The sampled current is substituted into the reconstruction expression to complete the XYZ low modulation ratio phase current reconstruction. Taking the low modulation ratio reconstruction region L1 as an example, the reconstruction process is explained as shown in Figure 5(a). I is obtained by sampling at 0Ts and 0.5Ts respectively. L1 I L2 According to Table 1, the reconstruction expression for the low modulation ratio reconstruction region L1 is Equation (2). Substituting the sampling current, the three-phase currents of XYZ can be reconstructed.

[0133]

[0134] Figures 7(a) to 7(c) The phase current reconstruction results are presented when operating in the low modulation ratio region. Under this condition, the three-phase reconstruction current still maintains good sinusoidal characteristics. According to the comparison results of the X-phase reconstruction current and the measured current, as well as the error curve shown in Figure 7(c), it can also be seen that the fundamental frequency of the reconstruction current can still follow the actual current well in the low modulation ratio region.

[0135] During the motor startup process, it is inevitable to pass through a low modulation ratio region. Therefore, it is necessary to verify the accuracy of the DTP-PMSM phase current reconstruction technology under this dynamic process.

[0136] Figures 9(a) to 9(c)The phase current reconstruction results are presented during the dynamic process of the motor from zero speed and zero load to 40 r / min (0.32 pu) speed and 110 N·m load. Figures 9(a) and 9(b) show the actual and reconstructed current waveforms of the three-phase windings XYZ at this time, respectively. Figures 9(a) to 9(c) It can be seen that the method proposed in this embodiment effectively eliminates the low modulation ratio reconfiguration blind zone. Throughout the dynamic process, the three-phase reconfiguration current of the DTP-PMSM can be smoothly started from the low modulation ratio region.

[0137] The collected rotation position information is combined with the reconstructed XYZ three-phase current for coordinate transformation. The three-phase current is then fed into the Clark-Park transformation of equation (3) to obtain the XYZ winding torque current feedback value i. q2 With excitation current feedback value i d2 .

[0138]

[0139] Motor speed and angular position are collected. No angular position compensation is performed in the low modulation ratio region. The collected speed is fed into the speed loop calculation to obtain the torque current command. The commanded current is then compared with the torque current feedback value i. q2 With excitation current feedback value i d2 The difference is fed into the current loop, and the three-phase modulation reference voltage U is obtained through current loop calculation. d2 U q2 The reference voltage is fed into a three-phase space vector pulse width modulator to calculate the specific drive information for each power module, thus completing the waveform generation. In addition, the ABC drive signals of the three-phase windings are set low to perform waveform blocking processing on the power modules.

[0140] Step 2: The switching controller adjusts the bus voltage U dc Sampling is performed, and the magnitude of the minimum sampled vector is calculated according to equation (4).

[0141]

[0142] In the formula U Min T is the minimum sampled vector; Min This is the minimum sampling time.

[0143] Based on the quadrature-axis voltage u output from the XYZ current loop q2 With direct-axis voltage u d2 Calculate the XYZ reference voltage magnitude |u ref-XYZ |

[0144]

[0145] The switching state is judged according to equation (6). When equation (6) is satisfied, the state variable Mode = 0. The system continues to operate in the low modulation ratio region and proceeds to 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 system with state variable Mode = 1 enters the normal modulation ratio region and proceeds to step 3.

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

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

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

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

[0154] in accordance with Figure 1 The control system is reorganized according to the state variable Mode=1.

[0155] Step 3: In the normal modulation ratio region, the two sets of three-phase windings operate in coordination, shifting the carrier phase of the three-phase windings XYZ by 0.25T. s ;

[0156] When S A =0, S B =0, S C =0 or S X =0, SY =0, S Z When = 0, the corresponding voltage vector is U0;

[0157] When S A =1, S B =0, S C =0 or S X =1, S Y =0, S Z When = 0, the corresponding voltage vector is U1;

[0158] When S A =1, S B =1, S C =0 or S X =1, S Y =1, S Z =0 corresponds to the voltage vector U2;

[0159] When S A =0, S B =1, S C =0 or S X =0, S Y =1, S Z When = 0, the corresponding voltage vector is U3;

[0160] When S A =0, S B =1, S C =1 or S X =0, S Y =1, S Z When = 1, the corresponding voltage vector is U4;

[0161] When S A =0, S B =0, S C =1 or S X =0, S Y =0, S Z When = 1, the corresponding voltage vector is U5;

[0162] When S A =1, S B =0, S C =1 or S X =1, S Y =0, S Z When = 1, the corresponding voltage vector is U6;

[0163] When S A =1, S B =1, S C =1 or S X =1, S Y =1, S ZWhen = 1, the corresponding voltage vector is U7;

[0164] The region enclosed by voltage vectors U1 and U2 in space is sector I;

[0165] The region enclosed in space by voltage vectors U2 and U3 is sector II;

[0166] The region enclosed in space by voltage vectors U3 and U4 is sector III;

[0167] The region enclosed in space by voltage vectors U4 and U5 is sector IV;

[0168] The region enclosed in space by voltage vectors U5 and U6 is sector V;

[0169] The region enclosed in space by voltage vectors U6 and U1 is sector VI;

[0170] For sectors I to VI, take the midpoint line within each sector. The area enclosed by the midpoint line of sector I and the midpoint line of sector VI is the normal modulation ratio region G1.

[0171] The region enclosed by the midpoint line of sector II and the midpoint line of sector I is the normal modulation ratio region G2;

[0172] The region enclosed by the midpoint line of sector II and the midpoint line of sector III is the normal modulation ratio region G3;

[0173] The region enclosed by the midpoint line of sector III and the midpoint line of sector IV is the normal modulation ratio region G4;

[0174] The region enclosed by the midpoint line of sector IV and the midpoint line of sector V is the normal modulation ratio region G5;

[0175] The region enclosed by the midpoint of sector V and the midpoint of sector VI is the normal modulation ratio region G6;

[0176] 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 enclosed by the midpoint of sector VI and the voltage vector U1 is the normal modulation ratio region G1-Ⅰ, and the region enclosed by the midpoint of sector Ⅰ and the voltage vector U1 is the normal modulation ratio region G1-Ⅱ.

[0177] The normal modulation ratio region G4 includes the normal modulation ratio region G4-Ⅰ and the normal modulation ratio region G4-Ⅱ. The region enclosed by the midpoint line of sector Ⅲ and the voltage vector U4 is the normal modulation ratio region G4-Ⅰ, and the region enclosed by the midpoint line of sector Ⅳ and the voltage vector U4 is the normal modulation ratio region G4-Ⅱ.

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

[0179] When the reference voltage vector is located at G1-Ⅰ, the sampling currents I1I2I3I4 are obtained by sampling at the switch vector combinations ABC-U2 XYZ-U1, ABC-U5XYZ-U1, ABC-U1 XYZ-U2, and ABC-U1 XYZ-U5 respectively.

[0180] When the reference voltage vector is located at G1-II, the sampling currents I1I2I3I4 are obtained by sampling at the switch vector combinations ABC-U6 XYZ-U1, ABC-U3XYZ-U1, ABC-U1 XYZ-U6, and ABC-U1 XYZ-U3 respectively.

[0181] When the reference voltage vector is located at G2, the sampling currents I1I2I3I4 are obtained by sampling at the switch vector combinations ABC-U0 XYZ-U2, ABC-U7 XYZ-U2, ABC-U2 XYZ-U0, and ABC-U2 XYZ-U7 respectively.

[0182] When the reference voltage vector is located at G3, the sampling currents I1I2I3I4 are obtained by sampling at the switch vector combinations ABC-U0 XYZ-U3, ABC-U7 XYZ-U3, ABC-U3 XYZ-U0, and ABC-U3 XYZ-U7 respectively.

[0183] When the reference voltage vector is located at G4-Ⅰ, the sampling currents I1I2I3I4 are obtained by sampling at the switch vector combinations ABC-U2 XYZ-U4, ABC-U5XYZ-U4, ABC-U4 XYZ-U2, and ABC-U4 XYZ-U5 respectively.

[0184] When the reference voltage vector is located at G4-II, the sampling currents I1I2I3I4 are obtained by sampling at the switch vector combinations ABC-U2 XYZ-U1, ABC-U5XYZ-U1, ABC-U1 XYZ-U2, and ABC-U1 XYZ-U5 respectively.

[0185] When the reference voltage vector is located at G5, the sampling currents I1I2I3I4 are obtained by sampling at the switch vector combinations ABC-U0 XYZ-U5, ABC-U7 XYZ-U5, ABC-U5 XYZ-U0, and ABC-U5 XYZ-U7 respectively.

[0186] When the reference voltage vector is located at G6, the sampling currents I1I2I3I4 are obtained by sampling at the switch vector combinations ABC-U0 XYZ-U6, ABC-U7 XYZ-U6, ABC-U6 XYZ-U0, and ABC-U6 XYZ-U7 respectively.

[0187] Based on 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 can be obtained from 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[U0]]> <![CDATA[U7]]> <![CDATA[U1]]> <![CDATA[U2]]> <![CDATA[U3]]> <![CDATA[U4]]> <![CDATA[U5]]> <![CDATA[U6]]> 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] Based on the normal modulation ratio region of the reference voltage, sampling is performed in the corresponding vector combination to obtain the sampling current I1I2I3I4.

[0192] In this embodiment, taking the normal modulation ratio region G1-Ⅰ as an example, sampling current I1 is obtained by sampling during the time period when the voltage vector U2 of the three-phase winding ABC of the switch vector combination overlaps with the voltage vector U1 of the XYZ. Sampling current I2 is obtained during the time period when the voltage vector U5 of the three-phase winding ABC of the switch vector combination overlaps with the voltage vector U1 of the XYZ. Sampling current I3 is obtained during the time period when the voltage vector U1 of the three-phase winding ABC of the switch vector combination overlaps with the voltage vector U2 of the XYZ. Sampling current I4 is obtained during the time period when the voltage vector U1 of the three-phase winding ABC of the switch vector combination overlaps with the voltage vector U5 of the XYZ.

[0193] Based on the operating voltage vectors of the two sets of three-phase windings at the sampling point, the correspondence between the sampling current and the phase current is obtained from Table 2. Solving for the phase current matrix completes the six-phase current reconstruction. Taking the normal modulation ratio region G1-Ⅰ as an example:

[0194] The sampling current I1 obtained during the time period when the three-phase winding ABC voltage vector U2 overlaps with the three-phase winding XYZ voltage vector U1 is shown in Table 2. The current i generated by the three-phase winding ABC voltage vector U2 in the current sensor is... CThe three-phase winding XYZ voltage vector U1 is 0 in the current sensor. The superposition of these two values ​​indicates that the sampling current i... C +0.

[0195] The sampling current I2 is obtained during the time period when the three-phase winding ABC voltage vector U5 overlaps with the three-phase winding XYZ voltage vector U1. Referring to Table 2, the current i generated by the three-phase winding ABC voltage vector U5 in the current sensor is... B The three-phase winding XYZ voltage vector U1 is 0 in the current sensor. The superposition of these two values ​​indicates that the sampling current i... B +0.

[0196] The sampling current I3 is obtained by sampling during the time period when the three-phase winding ABC voltage vector U1 and the three-phase winding XYZ voltage vector U2 overlap. Referring to Table 2, the current generated by the three-phase winding ABC voltage vector U1 in the current sensor is -i. A The three-phase winding XYZ voltage vector U2 in the current sensor i Y By superimposing the two, we can see that the sampling current -i A +i Y .

[0197] The sampling current I4 is obtained during the time period when the three-phase winding ABC voltage vector U1 overlaps with the three-phase winding XYZ voltage vector U5. Referring to Table 2, the current generated by the three-phase winding ABC voltage vector U1 in the current sensor is -i. A The three-phase winding XYZ voltage vector U5 in the current sensor i Z By superimposing the two, we can see that the sampling current -i A +i Z .

[0198] Therefore, the relationship between the sampling current and the phase current at this time is:

[0199]

[0200] Combining the current constraint relationship (7), the following correspondence can be obtained:

[0201]

[0202] Inverting equation (9) yields the current reconstruction expression at this point:

[0203]

[0204] Based on the above solution process, the current reconstruction expressions for different reconstruction groups are summarized in Table 3;

[0205] Table 3. Sampling results of current sensors in different reconstruction groups and current reconstruction expressions.

[0206]

[0207]

[0208]

[0209] In the normal modulation ratio region, hybrid pulse width modulation (RHPWM) is used, where RHPWM is:

[0210] In the normal modulation ratio regions G1-Ⅰ and G4-Ⅰ, dynamic zero-state PWM is applied to replace the zero vectors U0 and U7 with the opposite effective vectors U2 and U5, respectively; in the normal modulation ratio regions G1-Ⅱ and G4-Ⅱ, dynamic zero-state PWM is applied to replace the zero vectors U0 and U7 with the opposite effective vectors U6 and U3, respectively.

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

[0212] Compensation is performed by sampling the rotation angle. In actual operation, the estimated direct-axis voltage of the motor 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. Based on its magnitude, the position compensation angle is adjusted to minimize the sum of the actual direct-axis voltages. In the normal modulation ratio range, compensation is performed on the rotation angle sampled by the motor resolver.

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

[0214]

[0215] In the formula: This is a theoretical estimate of the direct-axis voltage of the three-phase winding ABC; The direct-axis voltage of the three-phase windings XYZ; i d1 This is the theoretical estimate of the direct-axis current of the three-phase winding ABC; i d2 L represents the direct-axis current of the three-phase windings (XYZ); d For a rotating coordinate system, the inductance is a direct-axis inductance; L q For a rotating coordinate system, the quadrature-axis inductance is L; m R is the stator magnetizing inductance; ω is the electrical angle; s This is the stator resistance.

[0216] For the actual direct-axis voltage u d1 u d2 Filtering is performed to prevent excessive jitter during parameter adjustment, resulting in the filtered voltage u. d1-LPF u d2-LPF .

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

[0218]

[0219] The direct-axis voltage error of the two sets of three-phase windings is summed using equation (13) as the basis for resolver compensation.

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

[0221] Based on the magnitude of the d-axis back electromotive force, the position compensation angle is adjusted to balance the error and u. d-error Once the minimum value is reached, the machine stops and the compensated position angle θ is saved. Based on the position angle θ, the sampled rotational speed ω after resolver compensation is obtained. m .

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

[0223] Sampling speed ω m The torque current is fed into the speed loop calculation to obtain the torque current command. Since the torque current commands of the two sets of three-phase windings are equal, the six-phase current coordinate transformation is reconstructed to obtain the quadrature-direct axis current feedback i. d1 i q1 i d2 i q2 The six-phase modulated reference voltage U is obtained by combining the torque reference current with the current loop operation. d1 U q1 U d2 U q2 To prevent transient transitions where the given voltage is lower than the minimum sampling vector, the lower limit of the output reference quadrature-axis voltage is limited using the minimum sampling voltage vector of 37V. This reference voltage is then fed into a six-phase modulation circuit to drive the power module.

[0224] The limiting formula is as shown in equation (14):

[0225]

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

[0227] |uref-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 operates under rated operating conditions with a reference voltage of 183V, which does not satisfy equation (15). Therefore, the state variable remains Mode = 1, and the system maintains normal modulation range operation, using a drive scheme with two sets of three-phase windings operating in coordination. When equation (15) is satisfied again, the system will re-enter the state of single three-phase winding operation, and at the same time, the loops corresponding to XYZ will be initialized with parameters.

[0230] Figures 8(a) to 8(c) The waveforms of the actual three-phase ABC current, the reconfigured three-phase ABC current, the actual three-phase XYZ current, and the reconfigured three-phase XYZ current during the dynamic switching process are given. According to... Figures 8(a) to 8(c) As can be seen, the method proposed in this invention effectively eliminates the low modulation ratio reconfiguration blind zone. Throughout the dynamic process, the three-phase reconfiguration current of the DTP-PMSM can smoothly transition from the low modulation ratio region to the normal modulation ratio region. Furthermore, the X-phase reconfiguration current closely follows the measured current.

[0231] Since the reconstruction method of this invention only involves low modulation ratio current reconstruction methods, reconstruction topologies, and switching control methods, this embodiment does not impose constraints on the controller, DTP-PMSM phase band angle, etc. This embodiment is also applicable to applications such as 30° phase-shifted DTP-PMSM speed loop controllers using active disturbance rejection controllers and current loop controllers using proportional resonant controllers.

[0232] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A switching control method for dual three-phase permanent magnet synchronous motors based on single current sensor sampling, characterized in that, The method includes: Step 1: In the low modulation ratio region, the three-phase windings XYZ operate independently. The three-phase windings ABC are subjected to wave blocking. 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 windings XYZ. The low modulation ratio three-phase current reconstruction is completed according to the three-phase current reconstruction expression in the low modulation ratio region. The reconstructed three-phase current and the sampled speed are sent into the loop for calculation to obtain the three-phase modulation reference voltage. After low modulation ratio mixed pulse width modulation, the power module drive is completed. Step 2: Calculate the minimum sampling vector based on the minimum sampling time. Determine the reference voltage magnitude of the three-phase winding XYX Does it meet the requirements? If yes, return to step 1; otherwise, proceed to step 3. Step 3: In the normal modulation ratio region, two sets of three-phase windings operate in coordination. A single current sensor is used to sample the sum of the current between the upper bridge arms of phases X and Y in the three-phase winding XYZ and the current between the lower bridge arms of phases A and B in the three-phase winding ABC at different sampling vector combinations. The six-phase current reconstruction is completed according to the six-phase current reconstruction expression in the normal modulation ratio region. The reconstructed six-phase current and the sampling speed are sent into the loop for calculation to obtain the modulation reference voltage. The modulation reference voltage of the quadrature axis is limited. Then, all modulation reference voltages are mixed pulse width modulation (RHPWM) to complete the power module drive. Step 4: Determine the reference voltage magnitude of the three-phase winding XYZ Does it meet the requirements? If yes, proceed to step 1; otherwise, proceed to step 3. Methods for obtaining the three-phase current reconstruction expression in the low modulation ratio region include: S A S B S C S X S Y S Z These are the six-phase bridge arm switching functions for a dual three-phase permanent magnet synchronous motor. A value of 0 indicates that the lower bridge arm is on, and a value of 1 indicates that the upper bridge arm is on. When S A =0、S B =0、S C =0 or S X =0、S Y =0、S Z When = 0, the corresponding voltage vector is U0; When S A =1、S B =0、S C =0 or S X =1、S Y =0、S Z When = 0, the corresponding voltage vector is U1; When S A =1、S B =1、S C =0 or S X =1、S Y =1、S Z When = 0, the corresponding voltage vector is U2; When S A =0、S B =1、S C =0 or S X =0、S Y =1、S Z When = 0, the corresponding voltage vector is U3; When S A =0、S B =1、S C =1 or S X =0、S Y =1、S Z When =1, the corresponding voltage vector is U4; When S A =0、S B =0、S C =1 or S X =0、S Y =0、S Z When =1, the corresponding voltage vector is U5; When S A =1、S B =0、S C =1 or S X =1、S Y =0、S Z When =1, the corresponding voltage vector is U6; When S A =1、S B =1、S C =1 or S X =1、S Y =1、S Z When =1, the corresponding voltage vector is U7; The region enclosed in space by voltage vectors U1 and U2 is the low modulation ratio reconstruction region L1; The region enclosed in space by voltage vectors U2 and U3 is the low modulation ratio reconstruction region L2; The region enclosed in space by voltage vectors U3 and U4 is the low modulation ratio reconstruction region L3; The region enclosed in space by voltage vectors U4 and U5 is the low modulation ratio reconstruction region L4; The region enclosed in space by voltage vectors U5 and U6 is the low modulation ratio reconstruction region L5; The region enclosed in space by voltage vectors U6 and U1 is the low modulation ratio reconstruction region L6; Based on the different low modulation ratio reconstruction regions where the reference voltage is located, the three-phase current reconstruction expression is determined as follows: in, , Indicates one switching cycle Two sampling times within; i X This represents the current in phase X of the three-phase winding XYZ; i Y This represents the current in the Y phase of the three-phase winding XYZ. i Z This represents the current in the Z phase of the three-phase winding XYZ; Low modulation ratio hybrid pulse width modulation includes: When the reference voltage vector is located in the low modulation ratio reconstruction region L1 or L4, the voltage vectors U0 and U7 of the three-phase winding XYZ are replaced with 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 windings XYZ are replaced with voltage vectors U5 and U2, respectively. When the reference voltage vector is located in the low modulation ratio reconstruction region L3 or L6, the voltage vectors U0 and U7 of the three-phase winding XYZ are replaced with 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 windings XYZ are replaced with voltage vectors U3 and U6, respectively.

2. The switching control method for dual three-phase permanent magnet synchronous motors according to claim 1, characterized in that, The methods for obtaining the modulation ratio normal region six-phase current reconstruction expression include: S A S B S C S X S Y S Z These are the six-phase bridge arm switching functions for a dual three-phase permanent magnet synchronous motor. A value of 0 indicates that the lower bridge arm is on, and a value of 1 indicates that the upper bridge arm is on. When S A =0、S B =0、S C =0 or S X =0、S Y =0、S Z When = 0, the corresponding voltage vector is U0; When S A =1、S B =0、S C =0 or S X =1、S Y =0、S Z When = 0, the corresponding voltage vector is U1; When S A =1、S B =1、S C =0 or S X =1、S Y =1、S Z When = 0, the corresponding voltage vector is U2; When S A =0、S B =1、S C =0 or S X =0、S Y =1、S Z When = 0, the corresponding voltage vector is U3; When S A =0、S B =1、S C =1 or S X =0、S Y =1、S Z When =1, the corresponding voltage vector is U4; When S A =0、S B =0、S C =1 or S X =0、S Y =0、S Z When =1, the corresponding voltage vector is U5; When S A =1、S B =0、S C =1 or S X =1、S Y =0、S Z When =1, the corresponding voltage vector is U6; When S A =1、S B =1、S C =1 or S X =1、S Y =1、S Z When =1, the corresponding voltage vector is U7; The region enclosed by voltage vectors U1 and U2 in space is sector I; The region enclosed in space by voltage vectors U2 and U3 is sector II; The region enclosed in space by voltage vectors U3 and U4 is sector III; The region enclosed in space by voltage vectors U4 and U5 is sector IV; The region enclosed in space by voltage vectors U5 and U6 is sector V; The region enclosed in space by voltage vectors U6 and U1 is sector VI; For sectors I to VI, take the midpoint line within each sector. The area enclosed by the midpoint line of sector I and the midpoint line of sector VI is the normal modulation ratio region G1. The region enclosed by the midpoint line of sector II and the midpoint line of sector I is the normal modulation ratio region G2; The region enclosed by the midpoint line of sector II and the midpoint line of sector III is the normal modulation ratio region G3; The region enclosed by the midpoint line of sector III and the midpoint line of sector IV is the normal modulation ratio region G4; The region enclosed by the midpoint line of sector IV and the midpoint line of sector V is the normal modulation ratio region G5; The region enclosed by the midpoint of sector V and the midpoint of sector VI is the normal modulation ratio region 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 enclosed by the midpoint of sector VI and the voltage vector U1 is the normal modulation ratio region G1-Ⅰ, and the region enclosed by the midpoint 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 enclosed by the midpoint line of sector Ⅲ and the voltage vector U4 is the normal modulation ratio region G4-Ⅰ, and the region enclosed by the midpoint line of sector Ⅳ and the voltage vector U4 is the normal modulation ratio region G4-Ⅱ. The expression for the six-phase current reconstruction in the normal region with modulation ratio is: Among them, ABC-U i XYZ-U j Indicates the switching cycle The voltage vector corresponding to the three-phase windings 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 combination of four sampling vectors; i X This represents the current in phase X of the three-phase winding XYZ; i Y This represents the current in the Y phase of a three-phase winding XYZ; i Z This represents the current in phase Z of the three-phase winding XYZ; i A This represents the current in phase A of the three-phase winding ABC; i B This represents the current in phase B of a three-phase winding ABC; i C This represents the current in phase C of the three-phase winding ABC.

3. The switching control method for dual three-phase permanent magnet synchronous motors according to claim 1, characterized in that, Hybrid pulse width modulation (RHPWM) includes: Phase shift of the carrier wave of the three-phase winding XYZ In the normal modulation ratio region G1-Ⅰ and the normal modulation ratio region G4-Ⅰ, dynamic zero-state PWM modulation is applied to replace voltage vectors U0 and U7 with voltage vectors U2 and U5, respectively. In the normal modulation ratio region G1-Ⅱ and the normal modulation ratio region G4-Ⅱ, dynamic zero-state PWM modulation is applied to replace voltage vectors U0 and U7 with voltage vectors U6 and U3, respectively. In the modulation ratio normal regions G2, G3, G5, and G6, SVPWM modulation is used.

4. The switching control method for dual three-phase permanent magnet synchronous motors according to claim 1, characterized in that, Limit the modulation reference voltage of the quadrature axis: To represent the modulation reference voltage of the quadrature axis, Indicates the switching cycle. Indicates the minimum sampling time. This indicates the bus voltage.

5. The switching control method for dual three-phase permanent magnet synchronous motors according to claim 1, characterized in that, In the normal modulation ratio region, the method for obtaining the sampling rotation speed includes: The theoretical estimate of the direct-axis voltage output by the current loop controller ACR-PI is: In the formula: This is the theoretical estimate of the direct-axis voltage of the first set of three-phase windings; This is the direct-axis voltage of the second set of three-phase windings; This is the theoretical estimate of the direct-axis current of the first set of three-phase windings; For the direct-axis current of the second set of three-phase windings; This is the theoretical estimate of the quadrature axis current for the first set of three-phase windings; For the quadrature axis current of the second set of three-phase windings; For a rotating coordinate system, the inductor is a direct-axis inductor. For the quadrature-axis inductance in a rotating coordinate system; L m For stator magnetizing inductance; It is an electrical angle; Stator resistance; For the given value of flux linkage voltage , Filtering is performed to obtain the filtered voltage. , ; Voltage error obtained: Summing the direct-axis voltage errors of the two sets of three-phase windings, we obtain... As a basis for resolver compensation: The initial position angle of the motor is determined based on the magnitude of the direct-axis voltage. Perform resolver compensation to reduce errors and Once the minimum value is reached, the compensated position angle is saved. According to the position angle The sampling speed after resolver compensation is obtained. .

6. A computer-readable storage device storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the switching control method for dual three-phase permanent magnet synchronous motors as described in any one of claims 1 to 5.

7. A switching control device for a dual three-phase permanent magnet synchronous motor, 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 switching control method for dual three-phase permanent magnet synchronous motors as described in any one of claims 1 to 5.

8. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the switching control method for dual three-phase permanent magnet synchronous motors as described in any one of claims 1 to 5.

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