Low modulation ratio region switching control method for dual three-phase permanent magnet synchronous motor

Abstract

The application discloses a low modulation ratio region switching control method of a double three-phase permanent magnet synchronous motor, solves the problem that two sets of three-phase windings need to work together in the low modulation ratio region of a traditional DTP-PMSM, and there is an operation efficiency optimization space, and belongs to the field of motor driving. The application comprises the following steps: in the low modulation ratio region, three-phase windings ABC independently operate, sampling is carried out at two zero vectors, current reconstruction is completed according to the sampling current; modulation reference voltage is obtained according to the reconstructed three-phase current and the sampling rotating speed, and driving is carried out after modulation; in the normal modulation ratio region, two sets of three-phase windings cooperate to operate, three-phase winding XYZ carriers are shifted by 0.25T s , sampling is carried out at the zero vectors of the two sets of three-phase windings, current reconstruction is completed according to the sampling results, modulation reference voltage is obtained according to the reconstructed six-phase current and the sampling rotating speed, and driving is carried out after amplitude limiting and modulation. The control method of the application only needs one set of three-phase windings to operate in the low modulation ratio region, and the operation efficiency of the system is improved.

Description

TECHNICAL FIELD

[0001] The application relates to a low modulation ratio region switching control method of a dual-three-phase permanent magnet synchronous motor, and belongs to the field of motor driving. BACKGROUND

[0002] A dual-three-phase permanent magnet synchronous motor (DTP-PMSM) has high power density and high reliability and thus occupies an important position in transportation and modern industry. The DTP-PMSM is widely used in fields with complex working conditions, such as aerospace, electric vehicles and locomotives, and there is a demand for frequent switching of the modulation ratio of the DTP-PMSM in these fields. A traditional DTP-PMSM vector control variable frequency system works with two sets of three-phase windings, and there is a space for further optimization of the running efficiency of the system in the low modulation ratio operation region.

[0003] At present, methods for eliminating the current reconstruction blind area in the low modulation ratio region include the measurement pulse insertion method, the vector phase shift method and the dynamic zero state pulse width modulation method. The measurement pulse insertion method inserts a measurement pulse in a PWM cycle to complete sampling and proposes a corresponding compensation strategy. This method changes the symmetry of PWM, increases the switching action frequency of the power module and increases the loss, reduces the system efficiency, and the control algorithm is relatively complex and is not suitable for high switching frequency scenes. The basic idea of the vector phase shift method is to adjust the phase of the PWM signal to change the central symmetrical seven-segment pulse width modulation into an asymmetric form, so that current sampling and reconstruction can be more effectively performed during the voltage vector action. However, this method introduces even-order switching frequency harmonics to increase the vibration of the motor, and cannot comprehensively cover the low modulation ratio region. The dynamic zero state pulse width modulation method eliminates the current reconstruction blind area in the low modulation ratio region by replacing the zero vector with an effective voltage vector. This method can ensure the symmetry of PWM but still increases the system harmonics and the vibration of the motor, which is not conducive to the stable operation of the electric drive system in the low modulation ratio region, and cannot further improve the running efficiency of the drive system. When the methods for eliminating the current reconstruction blind area in the low modulation ratio region of the DTP-PMSM vector control variable frequency system are different, an explicit and efficient switching control method needs to be given for different reconstruction schemes. The switching of the current reconstruction schemes under different modulation ratios may cause difficulty in the current reconstruction of the wide modulation ratio range, and there is a space for further optimization.

[0004] The traditional DTP-PMSM vector control variable frequency system needs two sets of three-phase windings to work together in the low modulation ratio region, and there is a space for optimization of the running efficiency. The switching of the DTP-PMSM current reconstruction schemes under different modulation ratios leads to difficulty in the current reconstruction of the wide modulation ratio range. SUMMARY

[0005] The application provides a low-modulation-ratio region switching control method of a double three-phase permanent magnet synchronous motor.

[0006] The low-modulation-ratio region switching control method of the double three-phase permanent magnet synchronous motor provided by the application comprises the following steps:

[0007] Step 1: the three-phase winding ABC is independently operated, the three-phase winding XYZ is processed by clamping, sampling is performed at two zero vectors in the three-phase winding ABC, low-modulation-ratio three-phase current reconstruction is completed according to the sampling current, the reconstructed three-phase current and the sampling rotating speed are input into a loop for operation to obtain a three-phase modulation reference voltage, and power module driving is completed through three-phase space vector pulse width modulation;

[0008] Step 2: the modulation ratio M of the current three-phase winding ABC is calculated, when the modulation ratio M satisfies , T min is the minimum sampling time; T s is a switching period, and the step 1 is entered, otherwise the step 3 is entered;

[0009] Step 3: the two sets of three-phase windings are cooperatively operated, the three-phase winding XYZ carrier is shifted by 0.25T s , sampling is performed at the zero vectors of the two sets of three-phase windings respectively, six-phase current reconstruction is completed according to the sampling results and a six-phase current reconstruction expression, the reconstructed six-phase current and the sampling rotating speed are input into a loop for operation to obtain a modulation reference voltage, the modulation reference voltage of the cross axis is limited in amplitude, and all the modulation reference voltages are subjected to three-phase space vector pulse width modulation and power module driving;

[0010] Step 4: whether the modulation ratio M of the three-phase winding ABC satisfies is determined, if yes, the step 1 is entered, and if no, the step 3 is entered.

[0011] Preferably, the low-modulation-ratio three-phase current reconstruction is completed according to the sampling current:

[0012] S A , S B , S C , S X , S Y , S Z respectively are six-phase bridge arm switching functions of the double three-phase permanent magnet synchronous motor, and the value 0 represents that the lower bridge arm is turned on, and the value 1 represents that the upper bridge arm is turned on;

[0013] The current I is obtained by sampling at the zero vector S A S B S C 000 of the three-phase winding ABC.L1 , the zero vector S A of the three-phase winding ABC B S C =111 is sampled to obtain the current I L2 ;

[0014] The low-modulation-ratio three-phase current i A i B i C are respectively:

[0015]

[0016] As preferred, the method for obtaining the six-phase current reconstruction expression comprises:

[0017] S A , S B , S C , S X , S Y , S Z are respectively six-phase bridge arm switching functions of the double three-phase permanent magnet synchronous motor, and the value 0 represents that the lower bridge arm is turned on, and the value 1 represents that 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 the 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 the 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 the 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 the voltage vector U3;

[0022] When SA = 0, S B = 1, S C = 1 or S X = 0, S Y = 1, S Z = 1, corresponding 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, corresponding 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, corresponding 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] The midlines of sectors I to VI are taken respectively;

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

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

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

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

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

[0037] The area surrounded by the middle line of sector V and the middle line of sector VI is a reconstruction area G6;

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

[0039]

[0040]

[0041] Wherein, I1, I2, I3, I4 respectively represent the currents sampled at the four zero vectors; A represents the current of phase A in the three-phase winding ABC;

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

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

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

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

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

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

[0048]

[0049] Wherein, U q represents the modulation reference voltage of the quadrature axis, T s represents the switching period, T min represents the minimum sampling time, U dc represents the bus voltage.

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

[0051]

[0052] Wherein, U dc represents the current bus voltage, U d1 , U q1 represents the three-phase modulation reference voltage of the direct axis and the quadrature axis.

[0053] As preferred, the reconstructed three-phase current is input into a loop for operation to obtain a three-phase modulation reference voltage, and a three-phase space vector pulse width modulation module is driven to include:

[0054] The reconstructed three-phase current i A i B i C is transformed to obtain a torque current feedback value i q1 of the three-phase winding ABC. d1 ;

[0055] The sampled speed is input into a speed controller ASR to obtain a torque given current, and the torque given current, the torque current feedback value i q1 and the excitation current feedback value i d1 are subtracted to be input into a current loop ACR, and the current loop ACR is operated to obtain three-phase modulation reference voltages U d1 and U q1 of the direct axis and the quadrature axis.

[0056] U d1 and U q1 are input into three-phase space vector pulse width modulation corresponding to the three-phase winding ABC to obtain specific driving information of each power module, complete wave emission, and in addition, the three-phase winding XYZ driving signal is low, and the corresponding power module is processed.

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

[0058]

[0059] Wherein, θ represents the motor position angle.

[0060] The control method of the application has the advantages that the low modulation ratio region of the application only needs one set of three-phase winding operation, which improves the system operation efficiency; the application can realize the reconstruction of the phase current in the low modulation ratio region of the DTP-PMSM driving system; the switching control method under different modulation ratios given by the application can realize the reconstruction of the phase current in a wide modulation ratio range. BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 The switching control block diagram of the DTP-PMSM low modulation ratio region, wherein θ is the DTP-PMSM electric angle, ω is the DTP-PMSM speed, I SAMPLE is the current Hall sampling value.

[0062] Figure 2 Flow chart for switching of DTP-PMSM control system under different modulation ratios

[0063] Figure 3 Topology chart for current reconstruction of DTP-PMSM

[0064] Fig. 4(a) is a waveform chart of three-phase winding ABC sector I carrier and PWM under low modulation ratio region;

[0065] Fig. 4(b) is a waveform chart of three-phase winding ABC sector II carrier and PWM under low modulation ratio region;

[0066] Figure 5 Low modulation ratio and normal modulation ratio reconstruction region

[0067] Fig. 6(a) is a waveform chart of output of independent three-phase current sensor;

[0068] Fig. 6(b) is a waveform chart of three-phase winding ABC real phase current under low modulation ratio region;

[0069] Fig. 6(c) is a waveform chart of three-phase winding ABC reconstructed phase current under low modulation ratio region;

[0070] Fig. 6(d) is a waveform chart of three-phase winding ABC A-phase real current and reconstructed current error under low modulation ratio region;

[0071] Fig. 7(a) is a waveform chart of three-phase winding ABC real phase current and reconstructed phase current under switching of different modulation ratio regions;

[0072] Fig. 7(b) is a waveform chart of three-phase winding XYZ real phase current and reconstructed phase current under switching of different modulation ratio regions;

[0073] Fig. 7(c) is a waveform chart of three-phase winding ABC A-phase real current and reconstructed current error under switching of different modulation ratio regions;

[0074] Fig. 8(a) is a waveform chart of three-phase winding ABC real phase current under motor starting under low modulation ratio region;

[0075] Fig. 8(b) is a waveform chart of three-phase winding ABC reconstructed phase current under motor starting under low modulation ratio region;

[0076] Fig. 8(c) is a waveform chart of three-phase winding ABC A-phase real current and reconstructed current error under motor starting under low modulation ratio region. DETAILED DESCRIPTION

[0077] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0078] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0079] The present application will be further described below in combination with the drawings and specific embodiments, but is not limited to the present application.

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

[0081] Step 1, in the low modulation ratio region, the three-phase winding ABC is independently operated, and the current I L1 is sampled at the zero vector 000 of the ABC winding. L2 According to formula (1), the three-phase current i A i B i C is reconstructed.

[0082]

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

[0084] The motor is started at a speed of 40 r / min (0.32 p.u.), as shown in Figure 2 , the motor is first operated in the low modulation ratio region. As shown in Figure 1 , the low modulation ratio region independently operates the three-phase winding ABC, the XYZ torque current is given as 0, and the XYZ drive is blocked.

[0085] According to FIG. 4(a) and FIG. 4(b), the sampling is performed at two zero vectors of the ABC winding, respectively, the sampling current is brought into formula (1), and the three-phase current is reconstructed. Figures 6(a) to 6(d)The reconstructed phase current is given when the motor runs in the low modulation ratio region, and the three-phase reconstructed current still maintains good sinusoidal characteristics. According to the comparison result of the A-phase reconstructed current and the actual current given in Fig. 6(d) and the error curve, it can be seen that the reconstructed current error amplitude is small, and the reconstructed current fundamental can still follow the actual current well in the low modulation ratio region.

[0086] In the starting process of the motor, the low modulation ratio region will inevitably be passed through, and therefore it is necessary to verify the accuracy of the DTP-PMSM phase current reconstruction technology in the dynamic process.

[0087] Figures 8(a) to 8(c) The phase current reconstruction result in the dynamic process of the motor from zero speed and zero load to 40r / min (0.32p.u) speed and 110N·m load is given, wherein Fig. 8(a) and Fig. 8(b) are the ABC three-phase actual and reconstructed current waveforms at this time. According to the comparison result of the A-phase reconstructed current and the actual current given in Fig. 8(c) and the error curve, it can be seen that the reconstructed current error amplitude is small, and the reconstructed current fundamental can still follow the actual current well in the low modulation ratio region. Figures 8(a) to 8(c) It can be seen that the method proposed in the application well eliminates the low modulation ratio reconstruction blind area, and the three-phase reconstructed current of the DTP-PMSM can be started smoothly from the low modulation ratio region in the entire dynamic process. The A-phase current reconstruction current shown in Fig. 8(c) well follows the actual current, and the current reconstruction error curve has small amplitude and almost no fluctuation.

[0088] As shown in Fig. 7(b), there is no three-phase XYZ current, and at this time, the low modulation ratio region only has the three-phase ABC winding working.

[0089] The three-phase current is sent into the Clark-Park transformation of 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, the collected speed is sent into the speed loop operation to obtain the torque current given value. The XYZ winding torque current given value is set to 0, and the reconstructed three-phase current of the ABC winding is transformed and combined with the torque given current to perform current loop operation to obtain the three-phase modulation reference voltage U d1 U q1 . The three-phase modulation reference voltage U d1 U q1 is sent into the three-phase space vector pulse width modulation to complete the wave emission, and the XYZ winding drive signal is low, and the power module is blocked.

[0092] Step 2, the controller samples the bus voltage U dc , and calculates the modulation ratio M of the three-phase winding ABC according to formula (3).

[0093]

[0094] According to the switching state of formula (4), when formula (4) is satisfied, the state variable Mode=0 system continues to run in the low modulation ratio area, and step 1 is completed, and the ABC three-phase winding drive is completed.

[0095]

[0096] In the formula, T min is the minimum sampling time; T s is the switching period.

[0097] In the embodiment, the motor speed is set to 40r / min (0.32p.u), the load torque is 110N·m, and the DC bus voltage is 550V. At this time, the ABC three-phase winding reference voltage amplitude is 55V, the minimum sampling time is 4us, and the switching period corresponds to a 10kHz switching frequency of 100us.

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

[0099]

[0100] The switching condition formula (4) is not satisfied, so the state variable Mode=0 system maintains the low modulation ratio area operation, and the single three-phase winding operation driving scheme is adopted.

[0101] In the embodiment, the motor speed from 40r / min (0.32p.u) to 125r / min (1p.u) is suddenly increased to the normal modulation ratio operation area of 1069N·m load.

[0102] Step 3, when formula (4) is not satisfied, the state variable Mode=1 system enters the non-low modulation ratio area operation, and at this time, the driving scheme of two sets of three-phase windings cooperating operation is adopted, and the three-phase winding XYZ carrier is shifted by 0.25T s .

[0103] S A , S B , S C , S X , S Y , S Z are six-phase bridge arm switching functions of the double three-phase permanent magnet synchronous motor, and the value of 0 represents the lower bridge arm conduction, and the value of 1 represents the upper bridge arm conduction.

[0104] After the XYZ three-phase winding carrier is shifted, according to Figure 1The control block diagram reorganizes the control system according to the state variable Mode=1. Zero vectors are respectively operated in the two sets of three-phase windings, 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 is sampled to obtain currents I1, I2, I3 and I4. The principle for selecting the effective vector is that when the reference voltage vector is located in the current reconstruction region Gi (i=1, 2…6), the effective vector Ui (i=1, 2…6) is selected.

[0105] S A =0, S B =0, S C =0 or S X =0, S Y =0, S Z =0 corresponds to the 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 the 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 the 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 the 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 the voltage vector U4;

[0110] When S A = 0, S B = 0, S C = 1 or S X = 0, S Y = 0, S Z = 1, the corresponding voltage vector is U5;

[0111] When S A = 1, S B = 0, S C = 1 or S X = 1, S Y = 0, S Z = 1, the corresponding voltage vector is U6;

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

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

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

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

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

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

[0118] The midlines in sector I to sector VI are taken respectively;

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

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

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

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

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

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

[0125] According to the two sets of three-phase winding operation voltage vectors S A SB S C S X S Y S Z By referring to Table 1, we can obtain the correspondence between the sampled current and the phase current. Combined with the current constraint relationship (6), we can 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 zero vector sampling of the ABC three-phase windings is used, S X S Y S Z Equal to 001, S is the zero vector sampling value for the XYZ three-phase windings. A S B S C Let's take 001 as an example. Looking up Table 1, we can see that S... 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 Therefore, the relationship between the sampling current and the phase current at this time is:

[0130]

[0131] Combining the current constraint relationship (6), we can obtain the following corresponding relationship:

[0132]

[0133] Inverting equation (8) yields the current reconstruction expression at this point:

[0134]

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

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

[0137]

[0138]

[0139] The sampling current is brought into Table 2 to 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 to obtain the torque current given. The two sets of three-phase winding torque current given are equal, and the six-phase current coordinate transformation is reconstructed to obtain the direct and quadrature axis current feedback i d1 i q1 i d2 i q2 The current loop is operated in combination with the torque given current to obtain the six-phase modulation reference voltage U d1 U q1 U d2 U q2 The output reference quadrature axis voltage lower limit is simultaneously limited by equation (10). The reference voltage is sent to the six-phase modulation complete power module drive.

[0141]

[0142] At this time, the switching state is judged according to equation (11). When equation (11) is satisfied, the state variable Mode = 1, and the system continues to operate in the normal modulation ratio area, completing the two sets of three-phase winding drive.

[0143]

[0144] The reconstructed current is brought into equation (2) in three-phase units to complete the Clark-Park transformation, and two sets of torque current feedback values i q1 i q2 and excitation current feedback values i d1 i d2 The current feedback value is subtracted from the given value and sent to the current loop operation, and the minimum sampling time interval 4us bus voltage 550V is brought into equation (11) to obtain the output reference quadrature axis voltage lower limit:

[0145]

[0146] Further, the six-phase modulation reference voltage U d1 U q1 U d2 U q2 is obtained through the current loop operation. The reference voltage is sent to the three-phase space vector pulse width modulation to obtain the six-phase power module drive signal, and the power module drive is completed.

[0147] Since the system works in the rated operating condition, formula (11) is not satisfied, so the state variable maintains Mode=1, the system keeps normal modulation region operation, and the driving scheme of two sets of three-phase windings cooperating operation is adopted.

[0148] Figures 7(a) to 7(c) The ABC three-phase actual, ABC three-phase reconstructed current, XYZ three-phase actual current and XYZ three-phase reconstructed current waveforms in the dynamic switching process are shown in the figures. Figures 7(a) to 7(c) It can be seen that the method proposed in the application eliminates the low modulation ratio reconstruction blind area well, and the three-phase reconstructed current of the DTP-PMSM can be smoothly transitioned from the low modulation ratio region to the normal modulation ratio region in the entire dynamic process.

[0149] Since the reconstruction method of the application only involves the low modulation ratio current reconstruction method, the reconstruction topology and the switching control method, the embodiment does not have constraints on the controller, the DTP-PMSM phase belt angle and the like. The embodiment is also applicable to application occasions such as the 30° phase shift angle DTP-PMSM speed loop controller adopting an active disturbance rejection controller and the current loop controller adopting a proportional resonant controller.

[0150] Although the application is described herein with reference to particular embodiments, it should be understood that these examples are merely set forth for purposes of example and illustration. It should be understood that many modifications, changes, and substitutions can be suggested to one skilled in the art without departing from the spirit and scope of the application as defined in the appended claims. It should be understood that different combinations of the dependent claims along with their associated features can be made with the features described herein. It should be understood that features described in relation to one example embodiment can be used in other example embodiments.

Claims

1. A low modulation ratio region switching control method of a dual three-phase permanent magnet synchronous motor, characterized by, Comprise: Step 1, three-phase winding ABC independent operation, three-phase winding XYZ does the wave processing, sampling is carried out at two zero vectors in the operation three-phase winding ABC, and the low modulation ratio three-phase current reconstruction is completed according to the sampling current; the reconstructed three-phase current and the sampling speed are sent into the loop for operation to obtain three-phase modulation reference voltage, and the power module is driven after three-phase space vector pulse width modulation is completed; Step 2, calculate the modulation ratio M of the current three-phase winding ABC, when the modulation ratio M meets T min is the minimum sampling time; T s is the switching period, go to Step 1, otherwise go to Step 3; Step 3, two sets of three-phase windings cooperate to run, three-phase winding XYZ carrier wave is shifted 0.25T s , respectively, in two sets of three-phase winding zero vector sampling, according to the sampling results combined with six-phase current reconstruction expression, complete six-phase current reconstruction, reconstruction of six-phase current and sampling speed into the loop for operation, get the modulation reference voltage, and the modulation reference voltage for the cross shaft amplitude limiting, all modulation reference voltage through three-phase space vector pulse width modulation, complete power module drive; Step 4, judge 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 region switching control method of a dual three-phase permanent magnet synchronous motor according to claim 1, characterized by, The low modulation ratio three-phase current reconstruction is completed according to the sampling current: S A 、S B 、S C 、S X 、S Y 、S Z are six-phase bridge arm switching functions of the dual three-phase permanent magnet synchronous motor, and the value of 0 represents that the lower bridge arm is turned on, and the value of 1 represents that the upper bridge arm is turned on. At the sampling of zero vector S A S B S C = 000, the current I L1 At the sampling of zero vector S A S B S C = 111, the current I L2 ; Low modulation ratio three-phase current i A i B i C respectively:

3. The low modulation ratio region switching control method of a dual three-phase permanent magnet synchronous motor according to claim 1, characterized by, The acquisition method of the six-phase current reconstruction expression comprises: S A 、S B 、S C 、S X 、S Y 、S Z are six-phase bridge arm switching functions of the dual three-phase permanent magnet synchronous motor, and the value of 0 represents the lower bridge arm conduction, and the value of 1 represents the upper bridge arm conduction. S A = 0, S B = 0, S C = 0 or S X = 0, S Y = 0, S Z = 0 corresponds to the voltage vector U0. When S A = 1, S B = 0, S C = 0 or S X = 1, S Y = 0, S Z = 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 = 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 = 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 = 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 = 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 = 1, the corresponding voltage vector is U6; the area enclosed by U1 and U2 in space is sector I; The area surrounded by U2 and U3 in space is sector II; The area surrounded by U3 and U4 in space is sector III; The area surrounded by U4 and U5 in space is sector IV; The area surrounded by U5 and U6 in space is sector V; The area surrounded by U6 and U1 in space is sector VI; The middle lines in sector I to sector VI are taken respectively; The area surrounded by the middle line of sector I and the middle line of sector VI is reconstruction area G1; the area surrounded by the middle line of sector II and the middle line of sector I is reconstruction area G2; the area surrounded by the middle line of sector II and the middle line of sector III is reconstruction area G3; the area surrounded by the middle line of sector III and the middle line of sector IV is reconstruction area G4; the area surrounded by the middle line of sector IV and the middle line of sector V is reconstruction area G5; the area surrounded by the middle line of sector V and the middle line of sector VI is reconstruction area G6; according to the different reconstruction areas where the reference voltage vectors are located, the six-phase current reconstruction expression is: Wherein, I1, I2, I3, I4 respectively represent the currents sampled at four zero vectors; i A denotes the current of phase A in the three-phase winding ABC; i B denotes the current of phase B in the three-phase winding ABC; i C denotes the current of phase C in the three-phase winding ABC; i X Ix represents the current in the X phase of the three-phase winding XYZ; i Y denotes the current of the Y phase in the three-phase winding XYZ i Z denotes the current in the Z phase of the three-phase winding XYZ.

4. The low modulation ratio region switching control method of a dual three-phase permanent magnet synchronous motor according to claim 1, characterized by, The modulation reference voltage of the quadrature axis is limited: where U q is the modulation reference voltage representing the quadrature axis, T s is the switching period, T min is the minimum sampling time, U dc is the bus voltage.

5. The low modulation ratio region switching control method of a dual three-phase permanent magnet synchronous motor according to claim 1, characterized by, The modulation ratio M of the three-phase winding ABC: where U dc represents the current bus voltage, U d1 , U q1 represents the three-phase modulation reference voltage of the direct and quadrature axes.

6. The low modulation ratio region switching control method of a dual three-phase permanent magnet synchronous motor according to claim 1, characterized by, The reconstructed three-phase current and the sampling speed are sent into the loop for operation to obtain three-phase modulation reference voltage, and the power module is driven after three-phase space vector pulse width modulation is completed, comprising: The reconstructed three-phase current i A i B i C The transformed torque current feedback value i q1 of the three-phase winding ABC is obtained d1 ; The sampling rotational speed is sent to the rotational speed controller ASR to obtain the torque given current. The torque given current and the torque current feedback value i q1 The excitation current feedback value i d1 is sent to the current loop ACR to obtain the three-phase modulation reference voltage U d1 , U q1 of the direct axis and the quadrature axis through the current loop ACR. U d1 , U q1 is sent into the corresponding three-phase winding ABC space vector pulse width modulation, get each power module specific drive information, complete the wave, in addition, the three-phase winding XYZ drive signal is low, the corresponding power module for wave processing.

7. The low modulation ratio region switching control method of a dual three-phase permanent magnet synchronous motor according to claim 6, characterized by, The reconstructed three-phase current i A i B i C The Clark-Park transformation is performed to obtain the torque current feedback value i q1 of the three-phase winding ABC d1 : Wherein, θ represents the motor position angle.

8. A storage device readable by a computer, the storage device storing a computer program, characterized in that, The computer program is executed by the processor to realize the steps of the low modulation ratio area switching control method of the double three-phase permanent magnet synchronous motor according to any one of claims 1 to 7.

9. A low modulation ratio region switching control device of 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 by, The processor executes the computer program to realize the steps of the low modulation ratio area switching control method of the double 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, The computer program is executed by the processor to realize the steps of the low modulation ratio area switching control method of the double three-phase permanent magnet synchronous motor according to any one of claims 1 to 7.

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