Low modulation ratio area switching control method of dual three-phase permanent magnet synchronous motor

Abstract

The invention discloses a low-modulation-ratio area switching control method of a dual three-phase permanent magnet synchronous motor, solves the problems that two sets of three-phase windings are required to work together in a low-modulation-ratio area of a traditional DTP-PMSM, and an operation efficiency optimization space exists, and belongs to the field of motor driving. The method comprises the steps that in a low modulation ratio area, a three-phase winding ABC operates independently, sampling is carried out at two zero vectors, and current reconstruction is completed according to sampled current; a modulation reference voltage is obtained according to the reconstructed three-phase current and the sampling rotating speed, and driving is carried out through modulation; in a normal modulation ratio area, the two sets of three-phase windings operate in a matched mode, carrier phase shifting is carried out on the three-phase windings XYZ by 0.25 Ts, sampling is carried out at the zero vector positions of the two sets of three-phase windings respectively, current reconstruction is completed according to the sampling result, modulation reference voltage is obtained according to the reconstructed six-phase current and the sampling rotating speed, amplitude limiting is carried out, and then driving is carried out through modulation. According to the control method, only one set of three-phase winding is needed for operation in a low-modulation-ratio area, and the system operation efficiency is improved.

Description

Technical Field

[0001] The invention relates to a low modulation ratio area switching control method for a dual three-phase permanent magnet synchronous motor, and belongs to the field of motor driving. Background Art

[0002] Dual-Three Phase Permanent Magnet Synchronous Motor (DTP-PMSM) plays an important role in transportation and modern industry due to its high power density and high reliability. Dual-Three Phase Permanent Magnet Synchronous Motor is widely used in fields with complex working conditions, such as aerospace, electric vehicles, locomotives, etc. These fields require frequent switching of DTP-PMSM modulation ratio. The traditional DTP-PMSM vector control frequency conversion system uses two sets of three-phase windings to work together. In the low modulation ratio operation area, the system has room for further optimization of operating efficiency.

[0003] At present, there are several methods to eliminate the current reconstruction blind area in the low modulation ratio area: measurement pulse insertion method, vector phase shift method, dynamic zero-state pulse width modulation method, etc. The measurement pulse insertion method completes sampling by inserting measurement pulses in the PWM cycle and proposes corresponding compensation strategies. This method changes the PWM symmetry, increases the switching frequency of the power module in disguise, increases losses, and reduces system efficiency. The control algorithm is relatively complex and is not suitable for high switching frequency scenarios. The basic idea of ​​the vector phase shift method is to change the central symmetrical seven-segment pulse width modulation to an asymmetrical form by adjusting the phase of the PWM signal, so that current sampling and reconstruction can be performed more effectively during the action of the voltage vector. However, this method introduces even switching frequency harmonics in disguise to increase motor vibration, and cannot fully cover the low modulation ratio area. The dynamic zero-state pulse width modulation method uses an effective voltage vector to replace the zero vector to eliminate the low modulation ratio current reconstruction blind area. Although this method can ensure PWM symmetry, it will still increase system harmonics and motor vibration, which is not conducive to the stable operation of the electric drive system in the low modulation ratio area, and cannot achieve further improvement in the operating efficiency of the drive system. 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.

[0004] The traditional DTP-PMSM vector control frequency conversion system requires two sets of three-phase windings to work together in the low modulation ratio area, and there is room for optimization of operating efficiency; the DTP-PMSM current reconstruction scheme switches and operates under different modulation ratios, which makes it difficult to reconstruct the phase current in a wide modulation ratio range. Summary of the invention

[0005] In view of the problem that the low modulation ratio area of ​​the traditional DTP-PMSM vector control frequency conversion system requires two sets of three-phase windings to work together, and there is room for optimization of operating efficiency, the present invention provides a low modulation ratio area switching control method for a dual three-phase permanent magnet synchronous motor.

[0006] A low modulation ratio area switching control method of a dual three-phase permanent magnet synchronous motor of the present invention comprises:

[0007] Step 1: The three-phase winding ABC operates independently, and the three-phase winding XYZ is subjected to wave sealing processing. Sampling is performed at two zero vectors in the running three-phase winding ABC, and low modulation ratio three-phase current reconstruction is completed according to the sampled current; 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 three-phase space vector pulse width modulation;

[0008] Step 2: Calculate the modulation ratio M of the current three-phase winding ABC. When the modulation ratio M satisfies When T min is the minimum sampling time; T s If it is a switching cycle, go to step 1, otherwise go to step 3;

[0009] Step 3: The two sets of three-phase windings work together to shift the phase of the three-phase winding XYZ carrier by 0.25T. s , respectively, sampling is performed at the zero vector of the two sets of three-phase windings, and the six-phase current reconstruction is completed according to the sampling results combined with the six-phase current reconstruction expression. The reconstructed six-phase current and the sampled 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. All modulation reference voltages are subjected to three-phase space vector pulse width modulation to complete the power module drive;

[0010] Step 4: Determine whether the modulation ratio M of the three-phase winding ABC satisfies If yes, go to step 1, if no, go to step 3.

[0011] As a preferred method, low modulation ratio three-phase current reconstruction is completed according to the sampled current:

[0012] 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;

[0013] The zero vector S of the three-phase winding ABC A S B S C =000 and obtain the current IL1 , the zero vector S of the three-phase winding ABC A S B S C =111 and the current I is sampled L2 ;

[0014] Low modulation ratio three-phase current i A i B i C They are:

[0015]

[0016] Preferably, the method for obtaining the six-phase current reconstruction expression includes:

[0017] 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;

[0018] S A =0, S B =0, S C =0 or S X =0, S Y =0, S Z =0 corresponds to voltage vector U0;

[0019] 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;

[0020] 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;

[0021] 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;

[0022] When SA =0, S B =1, S C =1 or S X =0, S Y =1, S Z =1 corresponds to voltage vector U4;

[0023] 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;

[0024] 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;

[0025] The area enclosed by U1 and U2 in space is sector I;

[0026] The area enclosed by U2 and U3 in space is sector II;

[0027] The area enclosed by U3 and U4 in space is sector III;

[0028] The area enclosed by U4 and U5 in space is sector IV;

[0029] The area enclosed by U5 and U6 in space is sector V;

[0030] The area enclosed by U6 and U1 in space is sector VI;

[0031] Take the median lines within sectors Ⅰ to VI respectively;

[0032] The area enclosed by the midline of sector I and the midline of sector VI is the reconstruction area G1;

[0033] The area enclosed by the midline of sector II and the midline of sector I is the reconstruction area G2;

[0034] The area enclosed by the midline of sector II and the midline of sector III is the reconstruction area G3;

[0035] The area surrounded by the midline of sector III and the midline of sector IV is the reconstruction area G4;

[0036] The area enclosed by the midline of sector IV and the midline of sector V is the reconstruction area G5;

[0037] The area enclosed by the midline of sector V and the midline of sector VI is the reconstruction area G6;

[0038] According to the different reconstruction regions where the reference voltage vector is located, the six-phase current reconstruction expression is:

[0039]

[0040]

[0041] Among them, I1, I2, I3, and I4 represent the currents sampled at the four zero vectors respectively; i A Represents the current of phase A in three-phase winding ABC;

[0042] i B Represents the current of phase B in three-phase winding ABC;

[0043] i C Represents the current of phase C in three-phase winding ABC;

[0044] i X It represents the current of phase X in three-phase winding XYZ;

[0045] i Y Indicates the current of phase Y in three-phase winding XYZ

[0046] i Z Represents the current of phase Z in the three-phase winding XYZ.

[0047] As a preference, the modulation reference voltage of the quadrature axis is limited:

[0048]

[0049] Among them, 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.

[0050] As a preferred embodiment, the modulation ratio M of the three-phase winding ABC is:

[0051]

[0052] Among them, U dc Indicates the current bus voltage, U d1 , U q1 Represents the three-phase modulation reference voltage of the direct axis and quadrature axis.

[0053] Preferably, the reconstructed three-phase current and the sampled speed are sent into a loop for calculation to obtain a three-phase modulation reference voltage, and the power module driving is completed by three-phase space vector pulse width modulation, including:

[0054] The reconstructed three-phase current i A i B i C Transform to obtain the torque current feedback value i of the three-phase winding ABC q1 and the excitation current feedback value i d1 ;

[0055] The sampled speed is sent to the speed controller ASR for calculation to obtain the torque given current. The torque given current and the torque current feedback value i q1 and the excitation current feedback value i d1 The difference is sent to the current loop ACR, and the three-phase modulation reference voltage U of the direct axis and quadrature axis is obtained through the current loop ACR operation. d1 , U q1 ;

[0056] Will U d1 , U q1 The three-phase space vector pulse width modulation corresponding to the three-phase winding ABC is input to obtain the specific driving information of each power module and complete the wave transmission. In addition, the three-phase winding XYZ driving signal is set low and the corresponding power module is sealed.

[0057] As a preferred method, the reconstructed three-phase current i A i B i C Perform Clark-Park transformation to obtain the torque current feedback value i of the three-phase winding ABC q1 and the excitation current feedback value i d1 :

[0058]

[0059] Where θ represents the motor position angle.

[0060] The beneficial effects of the present invention are as follows: the control method of the present invention only needs one set of three-phase windings to operate in the low modulation ratio region, thereby improving the system operation efficiency; the present invention can realize the phase current reconstruction in the low modulation ratio region of the DTP-PMSM drive system; 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 The DTP-PMSM low modulation ratio area switching control block diagram, where θ is the DTP-PMSM electrical angle, ω is the DTP-PMSM speed, I SAMPLE is the current Hall sampling value;

[0062] Figure 2 The switching flow chart of DTP-PMSM control system under different modulation ratios;

[0063] Figure 3 Reconstruct the topology diagram for DTP-PMSM current;

[0064] Figure 4(a) shows the carrier and PWM waveform of sector I of the three-phase winding ABC in the low modulation ratio area;

[0065] Figure 4(b) shows the carrier and PWM waveform of the three-phase winding ABC sector II in the low modulation ratio area;

[0066] Figure 5 Reconstructing regions for low and normal modulation ratios;

[0067] FIG6( a ) is an output waveform diagram of an independent three-phase operating current sensor;

[0068] Figure 6(b) is the real phase current waveform of the three-phase winding ABC in the low modulation ratio area;

[0069] Figure 6(c) is the reconstructed phase current waveform of the three-phase winding ABC in the low modulation ratio area;

[0070] Figure 6(d) shows the error between the real current and the reconstructed current of phase A in the three-phase winding ABC in the low modulation ratio region;

[0071] FIG7( a ) is a waveform diagram of the real phase current and the reconstructed phase current of the three-phase winding ABC when switching in different modulation ratio regions;

[0072] FIG7( b ) is a waveform diagram of the real phase current and the reconstructed phase current of the three-phase winding XYZ when switching in different modulation ratio regions;

[0073] Figure 7(c) shows the error between the real current and the reconstructed current of phase A in the three-phase winding ABC when switching between different modulation ratio regions;

[0074] Figure 8(a) is a real phase current waveform of the three-phase winding ABC of the motor starting in the low modulation ratio area;

[0075] Figure 8(b) is a diagram showing the reconstructed phase current waveform of the three-phase winding ABC of the motor starting in the low modulation ratio area;

[0076] Figure 8(c) shows the error between the real current and the reconstructed current of phase A in the three-phase winding ABC of the motor starting in the low modulation ratio area. DETAILED DESCRIPTION

[0077] 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.

[0078] 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.

[0079] 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.

[0080] The low modulation ratio area switching control method of the dual three-phase permanent magnet synchronous motor of this embodiment includes:

[0081] Step 1: In the low modulation operation area, the three-phase winding ABC operates independently, and the current I is sampled at the zero vector 000 of the ABC winding. L1 , the current I is sampled at the zero vector 111 of the three-phase winding ABC L2 According to formula (1), the three-phase current i of the three-phase winding ABC is completed A i B i C Refactoring.

[0082]

[0083] In this embodiment, a 30-pole, rated speed 125rpm, phase angle 60° zero phase shift double three-phase permanent magnet synchronous motor is used for simulation experiment, the switching frequency is 10kHz, and two sets of three-phase windings are independently star-connected. Figure 1 As shown, the main control loop adopts dual dq closed-loop control and reorganizes the control loop according to the switching controller instructions.

[0084] Start the motor at a speed of 40r / min (0.32pu), such as Figure 2 As shown in Figure 1, 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 winding ABC works, the XYZ torque current given value is 0, and the XYZ drive is closed.

[0085] According to Figure 4(a) and Figure 4(b), sampling is performed at the two zero vectors of the ABC windings respectively, and the sampled current is substituted into equation (1) to reconstruct the three-phase current. Figure 6(a) to Figure 6(d)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 A-phase reconstructed current and the measured current and the error curve given in Figure 6(d), it can be seen that the reconstructed current error amplitude is relatively large at this time, and the reconstructed current fundamental wave can still follow the actual current well in the low modulation ratio area.

[0086] 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.

[0087] Figure 8(a) to Figure 8(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 8(a) and Figure 8(b) are the actual and reconstructed current waveforms of the ABC three-phase at this time. 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 be smoothly started from the low modulation ratio area. The A-phase current reconstruction current shown in Figure 8(c) follows the measured current well, and the current reconstruction error curve has a small amplitude and almost no fluctuation.

[0088] As shown in Figure 7(b), there is no current in the three-phase XYZ. At this time, only the three-phase ABC windings are working in the low modulation ratio area.

[0089] The three-phase current is sent into the Clark-Park transformation formula (2) to obtain the ABC winding torque current feedback value i q1 and the excitation current feedback value i d1 .

[0090]

[0091] The motor speed and angular position are collected, and the collected speed is sent to the speed loop for calculation to obtain the torque current setting. The torque current setting of the three-phase winding XYZ is set to 0, and the three-phase current coordinates of the reconstructed three-phase winding ABC are transformed and combined with the torque setting current to perform current loop calculation to obtain the three-phase modulation reference voltage U d1 U q1 The three-phase modulation reference voltage U d1 U q1 The three-phase space vector pulse width modulation is sent in to complete the wave generation. In addition, the three-phase winding XYZ drive signal is set low to perform wave sealing processing on the power module.

[0092] Step 2: Switching controller for bus voltage U dc Sampling is performed and the modulation ratio M of the three-phase winding ABC is calculated according to formula (3).

[0093]

[0094] The switching state is judged according to formula (4). When formula (4) is satisfied, the state variable Mode=0 and the system continues to operate in the low modulation ratio area, and enters step 1 to complete the ABC three-phase winding drive.

[0095]

[0096] Where, T min is the minimum sampling time; T s is the switching cycle.

[0097] In this embodiment, 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 ABC three-phase winding is 55V, the minimum sampling time is 4us, and the switching cycle corresponds to a 10kHz switching frequency of 100us.

[0098] According to formula (3), the modulation ratio M of winding ABC is:

[0099]

[0100] The switching condition (4) is not satisfied, 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.

[0101] In this embodiment, the motor increases suddenly from a low modulation operation area with a speed of 40 r / min (0.32 pu) and a load of 110 N·m to a normal modulation ratio operation area with a speed of 125 r / min (1 p.u) and a load of 1069 N·m.

[0102] Step 3: When equation (4) is not satisfied, the state variable Mode = 1, the system enters the non-low modulation ratio region, and the driving scheme of two sets of three-phase windings working together is adopted, and the three-phase winding XYZ carrier phase is shifted by 0.25T. s ;

[0103] 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;

[0104] After the XYZ three-phase winding carrier is phase-shifted, according to Figure 1The control block diagram reorganizes the control system according to the state variable Mode = 1. The two sets of three-phase windings are respectively operated with zero vectors, i.e., S A S B S C =000, S A S B S C =111, S X S Y S Z =000, S X S Y S Z =111 and the effective vector combination to obtain the current I1I2I3I4. The effective vector selection principle is: when the reference voltage vector is located in the current reconstruction area Gi (i=1,2...6), select the effective vector Ui (i=1,2...6).

[0105] S A =0, S B =0, S C =0 or S X =0, S Y =0, S Z =0 corresponds to voltage vector U0;

[0106] 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;

[0107] 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;

[0108] 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;

[0109] 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;

[0110] 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;

[0111] 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;

[0112] The area enclosed by U1 and U2 in space is sector I;

[0113] The area enclosed by U2 and U3 in space is sector II;

[0114] The area enclosed by U3 and U4 in space is sector III;

[0115] The area enclosed by U4 and U5 in space is sector IV;

[0116] The area enclosed by U5 and U6 in space is sector V;

[0117] The area enclosed by U6 and U1 in space is sector VI;

[0118] Take the median lines within sectors Ⅰ to VI respectively;

[0119] The area enclosed by the midline of sector I and the midline of sector VI is the reconstruction area G1;

[0120] The area enclosed by the midline of sector II and the midline of sector I is the reconstruction area G2;

[0121] The area enclosed by the midline of sector II and the midline of sector III is the reconstruction area G3;

[0122] The area surrounded by the midline of sector III and the midline of sector IV is the reconstruction area G4;

[0123] The area enclosed by the midline of sector IV and the midline of sector V is the reconstruction area G5;

[0124] The area enclosed by the midline of sector V and the midline of sector VI is the reconstruction area G6;

[0125] According to the two sets of three-phase winding running voltage vector S at the sampling point A SB S C S X S Y S Z , query Table 1 to get the corresponding relationship between the sampled current and the phase current, and combine it with the current constraint relationship (6) to complete the six-phase current reconstruction.

[0126]

[0127] Table 1 Correspondence between current sensor sampling results and phase current under different voltage vectors

[0128]

[0129] In this embodiment, when the ABC three-phase winding zero vector is sampled, S X S Y S Z Equal to 001, XYZ three-phase winding zero vector sampling is S A S B S C The following is an example of S being equal to 001. X S Y S Z The current corresponding to 001 is i C -i B , S A S B S C The current corresponding to 001 is -i X , so the corresponding relationship between the sampling current and the phase current is:

[0130]

[0131] In combination with the current constraint equation (6), the following corresponding relationship can be obtained:

[0132]

[0133] By inverting equation (8), we can get the current reconstruction expression at this time:

[0134]

[0135] like Figure 5 As shown, according to the different reconstruction areas where the reference voltage vector is located, the six-phase current reconstruction expressions are solved according to the above solution method and summarized in Table 2.

[0136] Table 2 Sampling vectors and reconstruction expressions for different reconstruction regions

[0137]

[0138]

[0139] Substituting the sampled current into Table 2 can complete the six-phase current reconstruction.

[0140] The motor speed and angular position are collected, and the collected speed is sent to the speed loop for calculation to obtain the torque current setting. The torque current setting of 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, the lower limit of the output reference quadrature-axis voltage is limited by equation (10). The reference voltage is sent to the six-phase modulation to complete the power module drive.

[0141]

[0142] At this time, the switching state is judged according to formula (11). When formula (11) 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.

[0143]

[0144] Substitute the reconstructed current into equation (2) in units of three phases to complete the Clark-Park transformation, and obtain two sets of torque current feedback values ​​i q1 i q2 and the excitation current feedback value i d1 i d2 , the difference between the current feedback value and the given value is sent to the current loop for calculation, and at the same time, the minimum sampling time interval 4us bus voltage 550V is substituted into formula (11) to obtain the output reference quadrature axis voltage lower limit:

[0145]

[0146] Then, the six-phase modulation reference voltage U is obtained through current loop calculation. d1 U q1 U d2 U q2 The reference voltage is sent to the three-phase space vector pulse width modulation in units of three phases to obtain the six-phase power module driving signal to complete the power module driving.

[0147] Since the system works under rated conditions, equation (11) 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 (11) is satisfied again, the system will re-enter the state of single three-phase winding operation, and the loop corresponding to XYZ will be initialized.

[0148] Figure 7(a) to Figure 7(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 7(a) to Figure 7(c) It can be seen that the method proposed in the present invention eliminates the low modulation ratio reconstruction blind area very well. In the whole dynamic process, the three-phase reconstructed current of DTP-PMSM can smoothly transition from the low modulation ratio area to the normal modulation ratio area. And the A-phase current reconstruction current follows the measured current very well, and the current reconstruction error increases with the increase of current amplitude.

[0149] 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.

[0150] 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 low modulation ratio area switching control method for a dual three-phase permanent magnet synchronous motor, characterized in that: include: Step 1: The three-phase winding ABC operates independently, and the three-phase winding XYZ is subjected to wave sealing processing. Sampling is performed at two zero vectors in the running three-phase winding ABC, and low modulation ratio three-phase current reconstruction is completed according to the sampled current; 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 three-phase space vector pulse width modulation; Step 2: Calculate the modulation ratio M of the current three-phase winding ABC. When the modulation ratio M satisfies When T min is the minimum sampling time; T s If it is a switching cycle, go to step 1, otherwise go to step 3; Step 3: The two sets of three-phase windings work together to shift the phase of the three-phase winding XYZ carrier by 0.25T. s , respectively, sampling is performed at the zero vector of the two sets of three-phase windings, and the six-phase current reconstruction is completed according to the sampling results combined with the six-phase current reconstruction expression. The reconstructed six-phase current and the sampled 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. All modulation reference voltages are subjected to three-phase space vector pulse width modulation to complete the power module drive; Step 4: Determine whether the modulation ratio M of the three-phase winding ABC satisfies If yes, go to step 1, if no, go to step 3.

2. The low modulation ratio area switching control method of the dual three-phase permanent magnet synchronous motor according to claim 1 is characterized in that: Reconstruct low modulation ratio three-phase current based on sampled current: 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; The zero vector S of the three-phase winding ABC A S B S C =000 and obtain the current I L1 , the zero vector S of the three-phase winding ABC A S B S C =111 and the current I is sampled L2 ; Low modulation ratio three-phase current i A i B i C They are:

3. The low modulation ratio area switching control method of the dual three-phase permanent magnet synchronous motor according to claim 1 is characterized in that: The method for obtaining the six-phase current reconstruction expression 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; 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; the area enclosed by U1 and U2 in space is sector I; The area enclosed by U2 and U3 in space is sector II; The area enclosed by U3 and U4 in space is sector III; The area enclosed by U4 and U5 in space is sector IV; The area enclosed by U5 and U6 in space is sector V; The area enclosed by U6 and U1 in space is sector VI; Take the median lines within sectors Ⅰ to VI respectively; The area surrounded by the center line of sector I and the center line of sector VI is the reconstruction area G1; the area surrounded by the center line of sector II and the center line of sector I is the reconstruction area G2; the area surrounded by the center line of sector II and the center line of sector III is the reconstruction area G3; the area surrounded by the center line of sector III and the center line of sector IV is the reconstruction area G4; the area surrounded by the center line of sector IV and the center line of sector V is the reconstruction area G5; the area surrounded by the center line of sector V and the center line of sector VI is the reconstruction area G6; according to the different reconstruction areas where the reference voltage vector is located, the six-phase current reconstruction expression is: Among them, I1, I2, I3, and I4 represent the currents sampled at four zero vectors respectively; i A Represents the current of phase A in three-phase winding ABC; i B Indicates 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 It represents the current of phase X in 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.

4. The low modulation ratio area switching control method of the dual three-phase permanent magnet synchronous motor according to claim 1 is characterized in that: Limit the modulation reference voltage of the quadrature axis: Among them, 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.

5. The low modulation ratio area switching control method of the dual three-phase permanent magnet synchronous motor according to claim 1 is characterized in that: The modulation ratio M of the three-phase winding ABC is: Among them, U dc Indicates the current bus voltage, U d1 , U q1 Represents the three-phase modulation reference voltage of the direct axis and quadrature axis.

6. The low modulation ratio area switching control method of a dual three-phase permanent magnet synchronous motor according to claim 1, characterized in that: The reconstructed three-phase current and the sampled speed are sent into the loop for calculation to obtain the three-phase modulation reference voltage. The power module drive is completed through the three-phase space vector pulse width modulation, including: The reconstructed three-phase current i A i B i C Transform to obtain the torque current feedback value i of the three-phase winding ABC q1 and the excitation current feedback value i d1 ; The sampled speed is sent to the speed controller ASR for calculation to obtain the torque given current. The torque given current and the torque current feedback value i q1 and the excitation current feedback value i d1 The difference is sent to the current loop ACR, and the three-phase modulation reference voltage U of the direct axis and quadrature axis is obtained through the current loop ACR operation. d1 , U q1 ; Will U d1 , U q1 The three-phase space vector pulse width modulation corresponding to the three-phase winding ABC is input to obtain the specific driving information of each power module and complete the wave transmission. In addition, the three-phase winding XYZ driving signal is set low and the corresponding power module is sealed.

7. The low modulation ratio area switching control method of the dual three-phase permanent magnet synchronous motor according to claim 6 is characterized in that: The reconstructed three-phase current i A i B i C Perform Clark-Park transformation to obtain the torque current feedback value i of the three-phase winding ABC q1 and the excitation current feedback value i d1 : Where θ represents the motor position angle.

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 low modulation ratio area switching control method of a dual three-phase permanent magnet synchronous motor as claimed in any one of claims 1 to 7 are implemented.

9. A low modulation ratio area 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 low modulation ratio area switching control method of the dual three-phase permanent magnet synchronous motor 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 low modulation ratio area switching control method of a dual three-phase permanent magnet synchronous motor as claimed in any one of claims 1 to 7 are implemented.

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