Dual three-phase permanent magnet synchronous motor phase current reconstruction method based on single current sensor

Abstract

This invention discloses a phase current reconstruction method for a dual three-phase permanent magnet synchronous motor based on a single current sensor. The method simplifies the four-vector space vector modulation algorithm based on the common-mode voltage of the dual three-phase permanent magnet synchronous motor, and then performs phase current reconstruction based on a single current sensor. First, a reverse vector is inserted to increase the action time of the sampling vector, achieving the minimum sampling time requirement to eliminate the reconstruction blind zone. Next, current sampling is performed at the four sampling vectors based on the sector of the reference voltage, obtaining the inverter DC bus current containing six phase currents. Finally, combining the constraint that the sum of the three-phase currents of the two three-phase windings is zero, a six-equation of the six-phase current is obtained, and solving the equation achieves the reconstruction of the six-phase current. The proposed method requires only one current sensor and can achieve zero common-mode voltage, showing good prospects for engineering applications.

Description

Technical Field

[0001] This invention relates to the field of phase current reconstruction of dual three-phase permanent magnet synchronous motors, and in particular to a method for phase current reconstruction of dual three-phase permanent magnet synchronous motors based on a single current sensor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in industrial drives and electric vehicles due to their high power density, wide speed range, and good reliability. Traditional vector control systems typically employ three or two current sensors to acquire the motor phase current. Current sensors are installed on the lower arm of the inverter, sampling occurs when the lower arm switching devices are turned on. Simultaneously, a current sensor is installed on the DC bus to monitor and protect the bus current. Considering that multiple sensors increase controller size and cost, that sampling deviations from different sensors reduce system control performance, and that additional leads are required, a phase current reconstruction technique based on a single current sensor is proposed. Phase current reconstruction involves multiple samplings within the pulse width modulation period, combined with the inverter switching state, to extract phase current information. This technique uses only one current sensor and is more cost-effective than multi-current sensor systems. Summary of the Invention

[0003] The purpose of this invention is to address the problems existing in the prior art by proposing a phase current reconstruction method for dual three-phase permanent magnet synchronous motors based on a single current sensor.

[0004] The technical solution proposed in this invention is as follows: A phase current reconstruction method for a dual three-phase permanent magnet synchronous motor based on a single current sensor is characterized by simplifying a four-vector space vector modulation algorithm based on the common-mode voltage of the dual three-phase permanent magnet synchronous motor, and then performing phase current reconstruction based on a single current sensor. First, a reverse vector is inserted to increase the action time of the sampling vector to achieve the minimum sampling time requirement and eliminate the reconstruction blind zone. Then, current sampling is performed at the four sampling vectors based on the sector where the reference voltage is located to obtain the inverter DC bus current containing six-phase current. Finally, the six-equation of the six-phase current is obtained by combining the constraint relationship that the sum of the three-phase currents of the two three-phase windings is zero, and the reconstruction of the six-phase current is achieved by solving the equation.

[0005] The phase current reconstruction method for a dual three-phase permanent magnet synchronous motor based on a single current sensor includes the following steps: Step 1: Simplify the four-vector space vector modulation algorithm based on the common-mode voltage of the dual three-phase permanent magnet synchronous motor; Step 2: Determine the inserted reverse vector based on the sector, and obtain the space vector modulation waveform after the reverse vector is inserted; Step 3: Set four current sampling points in each cycle to collect four sets of inverter DC bus current; Step 4: Combining the constraint that the sum of the phase currents of the two three-phase windings is zero, the complete phase current is obtained by solving; Further analysis reveals that the common-mode voltage calculation formula for a dual three-phase permanent magnet synchronous motor is as follows:

[0006] In the formula, U cmv This refers to the common-mode voltage of a dual three-phase permanent magnet synchronous motor. U A , U B , U C , U U , U V , U W This represents the voltage at the midpoint of each bridge arm of the inverter.

[0007] Each space voltage vector can be represented by an octal number, and the corresponding binary number represents the switching state of the switching devices in the inverter. A value of 1 indicates the upper arm switch is on and the lower arm switch is off; a value of 0 indicates the upper arm switch is off and the lower arm switch is on. The sixty-four space voltage vectors are labeled as follows: V 00 arrive V 77 List the common-mode voltage generated when each space vector acts, and select twenty space vectors that generate zero common-mode voltage. Combine the space vector with the largest amplitude and the second largest amplitude in the same direction according to a certain action time ratio to form a virtual vector, thus obtaining six virtual vectors. Divide the entire vector plane into six sectors according to the spatial position of the virtual vectors: 0° to 45° and 345° to 360° are sector I, 45° to 105° is sector II, 105° to 165° is sector III, 165° to 225° is sector IV, 225° to 285° is sector V, and 285° to 345° is sector VI.

[0008] The switching on and off of switching devices, as well as current sampling, are not instantaneous; a minimum current sampling time is required. T min This is to ensure reliable sampling of the bus current.

[0009]

[0010] In the formula, T min Minimum sampling time, T dTo prevent dead time of short circuits in the upper and lower bridge arms of the inverter, T set The settling time of the switching device. T ad This refers to the digital-to-analog conversion time.

[0011] When the reference voltage is near the sector boundary, the duration of some space voltage vectors is less than the minimum sampling time, resulting in a reconstruction dead zone. To avoid this dead zone, while ensuring constant duty cycles and current harmonic suppression, a reverse voltage vector is inserted so that the duration of the space voltage vector used for current sampling is greater than the minimum sampling time. The insertion position and duration of the reverse voltage vector to be inserted in each sector are determined, resulting in the following sequence of space voltage vector actions for each sector: Sector I: V 07 - V 45 - V 46 - V 54 - V 64 - V 13 - V 23 - V 31 - V 32 - V 31 - V 23 - V 13 - V 64 - V 54 - V 46 - V 45 - V 07 ; Sector II: V 07 - V 26 - V 46 - V 62 - V 64 - V 13 - V 15 - V 31 - V51 - V 31 - V 15 - V 13 - V 64 - V 62 - V 46 - V 26 - V 07 ; Sector III: V 07 - V 26 - V 23 - V 62 - V 32 - V 45 - V 15 - V 54 - V 51 - V 54 - V 15 - V 45 - V 32 - V 62 - V 23 - V 26 - V 07 ; Sector IV: V 07 - V 13 - V 23 - V 31 - V 32 - V 45 - V 46 - V 54 - V 64 - V 54 -V 46 - V 45 - V 32 - V 31 - V 23 - V 13 - V 07 ; Sector V: V 07 - V 13 - V 15 - V 31 - V 51 - V 26 - V 46 - V 62 - V 64 - V 62 - V 46 - V 26 - V 51 - V 31 - V 15 - V 13 - V 07 ; Sector VI: V 07 - V 45 - V 15 - V 54 - V 51 - V 26 - V 23 - V 62 - V 32 - V 62 - V 23 - V26 - V 51 - V 54 - V 15 - V 45 - V 07 ; A current sensor is placed at the inverter's DC bus to measure the DC bus current. Under different switching states, the DC bus current contains different phase current information. Current sampling is performed at four sampling vectors in each sector to obtain four sets of DC bus currents. The relationship between the phase currents represented by the DC bus currents sampled from each sector is as follows: Sector I: In V 54 Sampling in reverse B Phase current and forward U The superposition of phase currents, in V 64 Sampling in reverse C Phase current and forward U The superposition of phase currents, in V 46 Sampling forward A Phase current and reverse W The superposition of phase currents, in V 45 Sampling forward A Phase current and reverse V The superposition of phase currents; Sector II: In V 62 Sampling in reverse C Phase current and forward V The superposition of phase currents, in V 64 Sampling in reverse C Phase current and forward U The superposition of phase currents, in V 46 Sampling forward A Phase current and reverse W The superposition of phase currents, in V 26 Forward sampling B Phase current and reverse W The superposition of phase currents; Sector III: In V 62 Sampling in reverse C Phase current and forward V The superposition of phase currents, in V 32Sampling in reverse A Phase current and forward V The superposition of phase currents, in V 23 Forward sampling B Phase current and reverse U The superposition of phase currents, in V 26 Forward sampling B Phase current and reverse W The superposition of phase currents; Sector IV: In V 31 Sampling in reverse A Phase current and forward W The superposition of phase currents, in V 32 Sampling in reverse A Phase current and forward V The superposition of phase currents, in V 23 Forward sampling B Phase current and reverse U The superposition of phase currents, in V 13 Forward sampling C Phase current and reverse U The superposition of phase currents; Sector V: In V 31 Sampling in reverse A Phase current and forward W The superposition of phase currents, in V 51 Sampling in reverse B Phase current and forward W The superposition of phase currents, in V 15 Forward sampling C Phase current and reverse V The superposition of phase currents, in V 13 Forward sampling C Phase current and reverse U The superposition of phase currents; Sector VI: In V 54 Sampling in reverse B Phase current and forward U The superposition of phase currents, in V 51 Sampling in reverse B Phase current and forward W The superposition of phase currents, in V 15 Forward samplingC Phase current and reverse V The superposition of phase currents, in V 45 Forward sampling A Phase current and reverse V The superposition of phase currents; The constraint relationship between the three-phase currents in the two three-phase windings of a dual three-phase permanent magnet synchronous motor is as follows:

[0012] In the formula i A , i B , i C , i U , i V , i W It is a six-phase current.

[0013] Combining the sampled six-phase current information, a matrix equation is constructed with the six-phase current as the variable. The matrix equation for each sector is as follows: Sector I:

[0014] Sector II:

[0015] Sector III:

[0016] Sector IV:

[0017] Sector V:

[0018] Sector VI:

[0019] In the formula, b 1, b 2, b 3, b 4 represents the DC bus current of the inverter obtained from sampling.

[0020] The matrix of each sector is solved to obtain the complete six-phase current in different sectors. Then, the six-phase current is output according to the sector to realize the phase current reconstruction of the dual three-phase permanent magnet synchronous motor based on a single current sensor.

[0021] Beneficial Effects: Due to the adoption of the above technical solution, this invention is applicable to a phase current reconstruction method for a dual three-phase permanent magnet synchronous motor based on a single current sensor, effectively solving the reconstruction blind zone problem in phase current reconstruction. By simplifying the four-vector space vector modulation algorithm, the common-mode voltage problem of the dual three-phase permanent magnet synchronous motor is effectively avoided. By reducing the use of current sensors, hardware costs are reduced. By inserting reverse vectors, the reconstruction blind zone problem in phase current reconstruction is effectively solved, reconstructing a complete six-phase current. Attached Figure Description

[0022] Figure 1 This is a block diagram of phase current reconfiguration control for a dual three-phase permanent magnet synchronous motor based on a single current sensor. Figure 2 This is a simplified spatial voltage vector distribution diagram; Figure 3 This is a simplified diagram of the phase current reconfiguration blind zone distribution of a dual three-phase permanent magnet synchronous motor. Figure 4 It shows the space vector modulation waveform after inserting the inverse vector and a schematic diagram of the sampling time. Detailed Implementation

[0023] like Figure 1 The control block diagram shown integrates the phase current reconstruction technology of dual three-phase permanent magnet synchronous motor based on a single current sensor into the vector control method of dual three-phase permanent magnet synchronous motor.

[0024] For a dual three-phase permanent magnet synchronous motor, the formula for calculating the common-mode voltage is:

[0025] In the formula, U cmv This refers to the common-mode voltage of a dual three-phase permanent magnet synchronous motor. U A , U B , U C , U U , U V , U W This represents the voltage at the midpoint of each bridge arm of the inverter.

[0026] Each space voltage vector can be represented by an octal number, and the corresponding binary number represents the switching state of the switching devices in the inverter. A value of 1 indicates the upper arm switch is on and the lower arm switch is off; a value of 0 indicates the upper arm switch is off and the lower arm switch is on. The sixty-four space voltage vectors are labeled as follows: V 00 arriveV 77 List the common-mode voltage generated when each space vector acts, and select twenty space vectors that generate zero common-mode voltage. Combine the space vector with the largest amplitude and the second largest amplitude in the same direction according to a certain action time ratio to form a virtual vector, thus obtaining six virtual vectors. Divide the entire vector plane into six sectors according to the spatial position of the virtual vectors: 0° to 45° and 345° to 360° are sector I, 45° to 105° is sector II, 105° to 165° is sector III, 165° to 225° is sector IV, 225° to 285° is sector V, and 285° to 345° is sector VI.

[0027] Figure 2 The distribution of virtual vectors is shown. Each virtual vector is composed of two space voltage vectors. The entire vector plane is divided into six sectors, numbered I to VI, in a counterclockwise order. Each sector contains an angle of 60 degrees.

[0028] The switching on and off of switching devices, as well as current sampling, are not instantaneous; a minimum current sampling time is required. T min This is to ensure reliable sampling of the bus current.

[0029]

[0030] In the formula, T min Minimum sampling time, T d To prevent dead time of short circuits in the upper and lower bridge arms of the inverter, T set The settling time of the switching device. T ad This refers to the digital-to-analog conversion time.

[0031] When the reference voltage is near the sector boundary, the duration of some space voltage vectors is less than the minimum sampling time, resulting in a reconstruction dead zone, such as... Figure 3 As shown, the system is divided into sector boundary dead zones and low modulation ratio dead zones. To avoid the occurrence of reconstruction dead zones, while ensuring that the duty cycle of each phase remains unchanged and current harmonics are suppressed, a reverse voltage vector is inserted so that the action time of the space voltage vector used for current sampling is greater than the minimum sampling time. The insertion position and action time of the reverse voltage vector to be inserted in each sector are determined, and the resulting order of action of the space voltage vectors in each sector is as follows: Sector I: V 07 - V 45 - V 46 -V 54 - V 64 - V 13 - V 23 - V 31 - V 32 - V 31 - V 23 - V 13 - V 64 - V 54 - V 46 - V 45 - V 07 ; Sector II: V 07 - V 26 - V 46 - V 62 - V 64 - V 13 - V 15 - V 31 - V 51 - V 31 - V 15 - V 13 - V 64 - V 62 - V 46 - V 26 - V 07 ; Sector III: V 07 - V 26 - V 23 - V 62 - V32 - V 45 - V 15 - V 54 - V 51 - V 54 - V 15 - V 45 - V 32 - V 62 - V 23 - V 26 - V 07 ; Sector IV: V 07 - V 13 - V 23 - V 31 - V 32 - V 45 - V 46 - V 54 - V 64 - V 54 - V 46 - V 45 - V 32 - V 31 - V 23 - V 13 - V 07 ; Sector V: V 07 - V 13 - V 15 - V 31 - V 51 - V 26 -V 46 - V 62 - V 64 - V 62 - V 46 - V 26 - V 51 - V 31 - V 15 - V 13 - V 07 ; Sector VI: V 07 - V 45 - V 15 - V 54 - V 51 - V 26 - V 23 - V 62 - V 32 - V 62 - V 23 - V 26 - V 51 - V 54 - V 15 - V 45 - V 07 ; Figure 4 The reverse vector insertion method is shown, which maintains waveform symmetry. The zero vector located at the center of the waveform is replaced, the duty cycle of each phase remains unchanged, and the action time of the space voltage vector that makes up the virtual vector is kept in a certain proportion to ensure the suppression of harmonic current.

[0032] A current sensor is placed at the inverter's DC bus to measure the DC bus current. Under different switching states, the DC bus current contains different phase current information. Current sampling is performed at four sampling vectors in each sector to obtain four sets of DC bus currents. The relationship between the phase currents represented by the DC bus currents sampled from each sector is as follows: Sector I: In V 54 Sampling in reverse B Phase current and forward U The superposition of phase currents, in V 64 Sampling in reverse C Phase current and forward U The superposition of phase currents, in V 46 Forward sampling A Phase current and reverse W The superposition of phase currents, in V 45 Forward sampling A Phase current and reverse V The superposition of phase currents; Sector II: In V 62 Sampling in reverse C Phase current and forward V The superposition of phase currents, in V 64 Sampling in reverse C Phase current and forward U The superposition of phase currents, in V 46 Forward sampling A Phase current and reverse W The superposition of phase currents, in V 26 Forward sampling B Phase current and reverse W The superposition of phase currents; Sector III: In V 62 Sampling in reverse C Phase current and forward V The superposition of phase currents, in V 32 Sampling in reverse A Phase current and forward V The superposition of phase currents, in V 23 Forward sampling B Phase current and reverse U The superposition of phase currents, in V 26 Forward sampling BPhase current and reverse W The superposition of phase currents; Sector IV: In V 31 Sampling in reverse A Phase current and forward W The superposition of phase currents, in V 32 Sampling in reverse A Phase current and forward V The superposition of phase currents, in V 23 Forward sampling B Phase current and reverse U The superposition of phase currents, in V 13 Forward sampling C Phase current and reverse U The superposition of phase currents; Sector V: In V 31 Sampling in reverse A Phase current and forward W The superposition of phase currents, in V 51 Sampling in reverse B Phase current and forward W The superposition of phase currents, in V 15 Forward sampling C Phase current and reverse V The superposition of phase currents, in V 13 Forward sampling C Phase current and reverse U The superposition of phase currents; Sector VI: In V 54 Sampling in reverse B Phase current and forward U The superposition of phase currents, in V 51 Sampling in reverse B Phase current and forward W The superposition of phase currents, in V 15 Forward sampling C Phase current and reverse V The superposition of phase currents, in V 45 Forward sampling A Phase current and reverse V The superposition of phase currents; The constraint relationship between the three-phase currents in the two three-phase windings of a dual three-phase permanent magnet synchronous motor is as follows:

[0033] In the formula i A , i B , i C , i U , i V , i W It is a six-phase current.

[0034] Combining the sampled six-phase current information, a matrix equation is constructed with the six-phase current as the variable. The matrix equation for each sector is as follows: Sector I:

[0035] Sector II:

[0036] Sector III:

[0037] Sector IV:

[0038] Sector V:

[0039] Sector VI:

[0040] In the formula, b 1, b 2, b 3, b 4 represents the DC bus current of the inverter obtained from sampling.

[0041] The matrix of each sector is solved to obtain the complete six-phase current in different sectors. Then, the six-phase current is output according to the sector to realize the phase current reconstruction of the dual three-phase permanent magnet synchronous motor based on a single current sensor.

[0042] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for reconstructing phase current of a dual three-phase permanent magnet synchronous motor based on a single current sensor, characterized in that, The four-vector space vector modulation algorithm is simplified based on the common-mode voltage of the dual three-phase permanent magnet synchronous motor. Then, phase current reconstruction based on a single current sensor is performed. First, a reverse vector is inserted to increase the action time of the sampling vector to achieve the minimum sampling time requirement and eliminate the reconstruction blind zone. Then, the current sampling is performed at the four sampling vectors by determining the sector where the reference voltage is located to obtain the inverter DC bus current containing the six-phase current. Finally, the six-element equation of the six-phase current is obtained by combining the constraint relationship that the sum of the three-phase currents of the two three-phase windings is zero. Solving the equation realizes the reconstruction of the six-phase current. The phase current reconstruction method for a dual three-phase permanent magnet synchronous motor based on a single current sensor includes the following steps: Step 1: Simplify the four-vector space vector modulation algorithm based on the common-mode voltage of the dual three-phase permanent magnet synchronous motor; Step 2: Determine the inserted reverse vector based on the sector, and obtain the space vector modulation waveform after the reverse vector insertion; Step 3: Set four current sampling points in each cycle to collect four sets of inverter DC bus currents; Step 4: Combining the constraint that the sum of the phase currents of the two three-phase windings is zero, the complete phase current is obtained by solving; The specific steps in step 1 are as follows: The formula for calculating the common-mode voltage of a dual three-phase permanent magnet synchronous motor is as follows:

2. In the formula, U cmv This refers to the common-mode voltage of a dual three-phase permanent magnet synchronous motor. U A , U B , U C , U U , U V , U W This represents the voltage at the midpoint of each bridge arm of the inverter. Each space voltage vector can be represented by an octal number, and the corresponding binary number represents the switching state of the switching devices in the inverter. A value of 1 indicates the upper arm switch is on and the lower arm switch is off; a value of 0 indicates the upper arm switch is off and the lower arm switch is on. The sixty-four space voltage vectors are labeled as follows: V 00 arrive V 77 List the common-mode voltage generated when each space vector acts, select twenty space vectors that generate zero common-mode voltage, and combine the space vector with the largest amplitude and the second largest amplitude in the same direction according to a certain action time ratio to form a virtual vector, thus obtaining six virtual vectors. Divide the entire vector plane into six sectors according to the spatial position of the virtual vectors: 0° to 45° and 345° to 360° are sector I, 45° to 105° is sector II, 105° to 165° is sector III, 165° to 225° is sector IV, 225° to 285° is sector V, and 285° to 345° is sector VI. The specific steps in step 2 are as follows: The switching on and off of switching devices, as well as current sampling, are not instantaneous; a minimum current sampling time is required. T min To ensure reliable sampling of the bus current; 3. In the formula, T min Minimum sampling time, T d To prevent dead time of short circuits in the upper and lower bridge arms of the inverter, T set The settling time of the switching device. T ad For digital-to-analog conversion time; When the reference voltage is near the sector boundary, the duration of some space voltage vectors is less than the minimum sampling time, resulting in a reconstruction blind zone. To avoid this blind zone, while ensuring the duty cycle of each phase remains constant and current harmonics are suppressed, a reverse voltage vector is inserted so that the duration of the space voltage vector used for current sampling is greater than the minimum sampling time. The insertion position and duration of the reverse voltage vector to be inserted in each sector are determined, and the resulting sequence of space voltage vector actions for each sector is as follows: Sector I: V 07 - V 45 - V 46 - V 54 - V 64 - V 13 - V 23 - V 31 - V 32 - V 31 - V 23 - V 13 - V 64 - V 54 - V 46 - V 45 - V 07 ; Sector II: V 07 - V 26 - V 46 - V 62 - V 64 - V 13 - V 15 - V 31 - V 51 - V 31 - V 15 - V 13 - V 64 - V 62 - V 46 - V 26 - V 07 ; Sector III: V 07 - V 26 - V 23 - V 62 - V 32 - V 45 - V 15 - V 54 - V 51 - V 54 - V 15 - V 45 - V 32 - V 62 - V 23 - V 26 - V 07 ; Sector IV: V 07 - V 13 - V 23 - V 31 - V 32 - V 45 - V 46 - V 54 - V 64 - V 54 - V 46 - V 45 - V 32 - V 31 - V 23 - V 13 - V 07 ; Sector V: V 07 - V 13 - V 15 - V 31 - V 51 - V 26 - V 46 - V 62 - V 64 - V 62 - V 46 - V 26 - V 51 - V 31 - V 15 - V 13 - V 07 ; Sector VI: V 07 - V 45 - V 15 - V 54 - V 51 - V 26 - V 23 - V 62 - V 32 - V 62 - V 23 - V 26 - V 51 - V 54 - V 15 - V 45 - V 07 ; The specific steps in step 3 are as follows: A current sensor is placed at the inverter's DC bus to measure the DC bus current. Under different switching states, the DC bus current contains different phase current information. Current sampling is performed at four sampling vectors in each sector to obtain four sets of DC bus current values. The relationship between the phase currents represented by the DC bus samples from each sector is as follows: Sector I: In V 54 Sampling in reverse B Phase current and forward U The superposition of phase currents, in V 64 Sampling in reverse C Phase current and forward U The superposition of phase currents, in V 46 Sampling forward A Phase current and reverse W The superposition of phase currents, in V 45 Sampling forward A Phase current and reverse V The superposition of phase currents; Sector II: In V 62 Sampling in reverse C Phase current and forward V The superposition of phase currents, in V 64 Sampling in reverse C Phase current and forward U The superposition of phase currents, in V 46 Sampling forward A Phase current and reverse W The superposition of phase currents, in V 26 Sampling forward B Phase current and reverse W The superposition of phase currents; Sector III: In V 62 Sampling in reverse C Phase current and forward V The superposition of phase currents, in V 32 Sampling in reverse A Phase current and forward V The superposition of phase currents, in V 23 Sampling forward B Phase current and reverse U The superposition of phase currents, in V 26 Sampling forward B Phase current and reverse W The superposition of phase currents; Sector IV: In V 31 Sampling in reverse A Phase current and forward W The superposition of phase currents, in V 32 Sampling in reverse A Phase current and forward V The superposition of phase currents, in V 23 Sampling forward B Phase current and reverse U The superposition of phase currents, in V 13 Sampling forward C Phase current and reverse U The superposition of phase currents; Sector V: In V 31 Sampling in reverse A Phase current and forward W The superposition of phase currents, in V 51 Sampling in reverse B Phase current and forward W The superposition of phase currents, in V 15 Sampling forward C Phase current and reverse V The superposition of phase currents, in V 13 Sampling forward C Phase current and reverse U The superposition of phase currents; Sector VI: In V 54 Sampling in reverse B Phase current and forward U The superposition of phase currents, in V 51 Sampling in reverse B Phase current and forward W The superposition of phase currents, in V 15 Sampling forward C Phase current and reverse V The superposition of phase currents, in V 45 Sampling forward A Phase current and reverse V The superposition of phase currents; Step 4: The constraint relationship between the three-phase currents in the two three-phase windings of a dual three-phase permanent magnet synchronous motor is as follows:

4. In the formula i A , i B , i C , i U , i V , i W It is a six-phase current; Combining the sampled six-phase current information, a matrix equation is constructed with the six-phase current as the variable. The matrix equation for each sector is as follows: Sector I:

5. Sector II:

6. Sector III:

7. Sector IV:

8. Sector V:

9. Sector VI:

10. In the formula, b 1, b 2, b 3, b 4 represents the DC bus current of the inverter obtained from sampling; The matrix of each sector is solved to obtain the complete six-phase current in different sectors. Then, the six-phase current is output according to the sector to realize the phase current reconstruction of a dual three-phase permanent magnet synchronous motor based on a single current sensor.

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