CN115913042A - Two-phase eight-vector direct torque control method of three-phase motor control circuit - Google Patents

Abstract

The invention discloses a two-phase eight-vector direct torque control method of a three-phase motor control circuit, which is characterized in that a complex plane is divided into a plurality of fans based on two-phase eight vectors and voltage vectors of the three-phase motor control circuitZone(s)And the electrical angle occupied by each sector is different, a voltage vector selection table is set through a flux linkage adjusting instruction and a torque adjusting instruction obtained by the hysteresis loop adjusting unit and the sector where the current flux linkage is located, and a proper switching signal is selected to control the inverter. Compared with other four-switch three-phase asynchronous motor control modes, the four-switch three-phase asynchronous motor control method adopts eight-vector direct torques synthesized to control, and two more eight-vector direct torques can well inhibit torque pulsation of the motor.

Description

Two-phase eight-vector direct torque control method of three-phase motor control circuit

Technical Field

The invention relates to a three-phase AC-DC-AC frequency conversion device, which is a two-phase eight-vector direct torque control method of a three-phase motor control circuit.

Background

At present, a three-phase asynchronous motor uses a voltage source type alternating-current-direct-current-alternating-phase six-switch frequency converter in the prior art in speed regulation, and the traditional topological structure of an IGBT (insulated gate bipolar translator) is utilized to meet most speed regulation requirements.

The prior art is based on a classical topological structure of the IGBT, and a three-phase four-switch topological structure for reducing the using quantity of the IGBT is further derived. Because the derived three-phase four-switch topological structure still takes voltage source type inversion as a basic structure, the speed regulation method of the three-phase four-switch topological structure is obtained by improving a conventional control strategy, stator flux linkage and torque are directly and respectively controlled, a current closed loop part is omitted, and better dynamic performance is obtained. Particularly in a high-power unit, the stator flux linkage is controlled in a hexagonal mode, and due to the fact that inertia potential energy of the high-power unit is large, the method can reduce switching times and further reduce element loss.

When one phase of a load is connected to the midpoint of a bus power supply to form a topology structure of four-switch inversion, the bus power supply voltage is reduced by half, different control methods are greatly influenced, and the four-switch inversion is also the main reason mainly used as a fault-tolerant and short-time coping strategy.

In the sine pulse width modulation process, the reduction of the voltage of the direct current power supply enables the effective value of the output alternating current to be reduced to 1/2 of the original value, and in the eight-vector direct torque pulse width modulation process:

1) Because the number of the switching tubes is reduced, the three-phase four-switch inverter can only output four basic voltage vectors with phases sequentially different by 90 degrees, compared with the traditional six-switch operation mode, the eight-vector direct torque sector is reduced from six to four, a zero voltage vector is lacked, the amplitude of the voltage vector is asymmetric, the switching of the voltage vector is not smooth enough in the inversion process, the inversion output is not as fine as the six-switch, and the torque pulsation of the motor is larger;

2) The amplitude of the output voltage vector is reduced to 1/2 of the original amplitude, so that the output torque of the motor is sharply reduced, and the load carrying capacity is reduced, therefore, the four-switch speed regulation performance is greatly reduced compared with the traditional frequency converter.

Therefore, the traditional four-switch inversion control can effectively reduce the use of full-control devices, but can only be used as a coping method when six-switch inversion fails.

Disclosure of Invention

The invention aims to provide a two-phase eight-vector direct torque control method of a three-phase motor control circuit, which can better reduce the torque pulsation of a four-switch three-phase asynchronous motor based on eight vectors aiming at the problem of large torque pulsation in the control of the four-switch three-phase asynchronous motor.

In order to achieve the above object, the present invention provides the following technical solutions.

The two-phase eight-vector direct torque control method of the three-phase motor control circuit is based on the three-phase motor control circuit and comprises a three-phase power supply, a rectifying circuit, a direct current bus circuit, an inverter circuit and a three-phase asynchronous motor, wherein the three-phase power supply, the rectifying circuit, the direct current bus circuit, the inverter circuit and the three-phase asynchronous motor are sequentially connected, the output end of the direct current bus circuit is connected with the input end of the inverter circuit, the rectifying circuit is a diode uncontrolled rectifying circuit, the direct current bus circuit comprises a first capacitor C1 and a second capacitor C2, the first capacitor C1 and the second capacitor C2 are connected in series, and the midpoint of the first capacitor C1 and the midpoint of the second capacitor C2 are connected with W of the three-phase asynchronous motor;

the inverter circuit comprises a U-phase inverter circuit and a V-phase inverter circuit;

the U-phase inverter circuit comprises a first thyristor VT1, a second thyristor VT2, an IGBT1, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4 and a third capacitor C3; the negative electrode of the first thyristor VT1 is respectively connected with the collector electrode of the IGBT1 and the positive electrode of the first diode D1, the positive electrode of the first thyristor VT1 is connected with the negative electrode of the first diode D1, the positive electrode of the second thyristor VT2 is respectively connected with the emitter electrode of the IGBT1 and the negative electrode of the second diode D2, the negative electrode of the second thyristor VT2 is connected with the positive electrode of the second diode D2, a third capacitor C3 is connected in parallel between the collector electrode and the emitter electrode of the IGBT1, the U of the three-phase asynchronous motor is connected between the third diode D3 and the fourth diode D4, the V-phase inverter circuit comprises a third thyristor VT3, a fourth thyristor VT4, an IGBT2, a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8 and a fourth capacitor C4, the negative electrode of the third thyristor VT3 is respectively connected with the collector electrode of the IGBT2 and the positive electrode of the fifth diode D5, the anode of the third thyristor VT3 is connected with the cathode of the fifth diode D5, the cathode of the sixth thyristor VT4 is connected with the emitter electrode of the fourth thyristor VT4, the fourth thyristor VT4 is connected between the emitter electrode of the IGBT2 and the asynchronous motor, and the emitter electrode of the asynchronous motor is connected between the fourth thyristor D6;

based on the three-phase motor control circuit, sector division is carried out again by defining voltage space vectors under the conduction condition, including selection of the voltage vectors under different conditions, and the conduction process of the circuit under the topological structure is optimized.

The voltage vector is specifically defined as follows:

establishing an alpha-beta coordinate system, defining that the A phase voltage vector of the three-phase asynchronous motor is in a 90-degree direction, the B phase voltage vector is in a-150-degree direction, and the C phase voltage vector is in a-30-degree direction, wherein the voltage vectors of all possible conduction states are eight and are respectively defined as a voltage vector U1, a voltage vector U2, a voltage vector U3, a voltage vector U4, a voltage vector U5, a voltage vector U6, a voltage vector U7 and a voltage vector U8;

defining a voltage vector U1 as a voltage vector when the IGBT2 and the fourth thyristor VT4 are conducted simultaneously; defining a voltage vector U2 as a voltage vector when the IGBT1 and the first thyristor VT1 and the IGBT2 and the fourth thyristor VT4 are conducted simultaneously; defining a voltage vector U3 as a voltage vector when the IGBT1 and the first thyristor VT1 are conducted simultaneously; defining a voltage vector U4 as a voltage vector when the IGBT1, the first thyristor VT1, the IGBT2 and the third thyristor VT3 are conducted simultaneously; defining a voltage vector U5 as a voltage vector when the IGBT2 and the third thyristor VT3 are simultaneously conducted; defining a voltage vector U6 as a voltage vector when the IGBT1 and the second thyristor VT2 as well as the IGBT2 and the third thyristor VT3 are simultaneously conducted; defining a voltage vector U7 as a voltage vector when the IGBT1 and the second thyristor VT2 are conducted simultaneously; the voltage vector U8 is defined as a voltage vector when the IGBT1 and the second thyristor VT2, and the IGBT2 and the fourth thyristor VT4 are turned on simultaneously.

The 8 voltage vectors divide the complex plane to form 8 sectors, the sectors are represented by theta (k), wherein k is the sector number, and the electrical angle occupied by each sector in the four-switch inverter control system is different;

flux linkage adjustment command psi obtained by hysteresis loop adjustment unit _Q And torque adjustment command T _Q And selecting a proper switching signal to control the inverter by setting a voltage vector selection table according to the sector theta (k) where the current flux linkage is located.

Taking θ (1) sector as an example, and assuming that the flux linkage rotates counterclockwise, then:

when psi _Q ＝1，T _Q =1, indicating that stator flux linkage needs to be increased, electromagnetic torque needs to be increased, and voltage vector V is selected ₁ ；

When psi _Q ＝1，T _Q =0, indicating that stator flux linkage needs to be increased, electromagnetic torque needs to be reduced, and selecting a voltage vector V ₈ ；

When psi _Q ＝0，T _Q =1, indicating that stator flux linkage needs to be reduced, electromagnetic torque needs to be increased, and voltage vector V is selected ₄ ；

When psi _Q ＝0，T _Q =0, indicating that stator flux linkage needs to be reduced, electromagnetic torque needs to be reduced, and selecting voltage vector V ₆ ；

The same applies to other sectors, and the voltage vector selection table can be obtained as follows:

compared with the prior art, the invention has the beneficial effects that:

the invention only needs four switches (namely two thyristors of each phase of two phases share one IGBT to replace two IGBTs) for frequency conversion speed regulation, regarding the inversion output, the midpoint of a capacitor C1 and a capacitor C2 of a direct current bus circuit is taken as a reference point to be used as the output of the phase C of the motor, and relative to the motor, a symmetrical three-phase waveform is actually formed to generate a rotating magnetic field, so that the motor can be driven to rotate. Compared with the traditional frequency conversion circuit, the main switching devices used by the eight-vector direct torque control strategy of the three-phase four-switch three-phase asynchronous motor are reduced, and voltage regulation and frequency conversion speed regulation are realized at the same time. Compared with other four-switch three-phase asynchronous motor control modes, the four-switch three-phase asynchronous motor control method adopts eight-vector direct torques synthesized to control, and two more eight-vector direct torques can well inhibit torque pulsation of the motor.

Drawings

FIG. 1 is a topological diagram of a two-phase eight-vector direct torque control method of a three-phase motor control circuit of the present invention;

FIG. 2 is a voltage eight vector diagram of a two phase eight vector direct torque control method of the three phase motor control circuit of the present invention;

FIG. 3 is a flux linkage sector distribution diagram of the two-phase eight-vector direct torque control method of the three-phase motor control circuit of the present invention;

fig. 4 is a schematic diagram of direct torque control of an asynchronous motor.

Detailed Description

The present invention will be described in further detail with reference to specific examples, but the embodiments of the present invention include, but are not limited to, the scope shown in the following examples.

The invention discloses a two-phase eight-vector direct torque control method of a three-phase motor control circuit, which improves the reference phases of a power supply and a load on a topological structure, adopts two-phase independent filtering inversion, directly connects the reference phases of the power supply and the load to the middle points of two groups of variable frequency circuit bus capacitors, provides that space voltage modulation is carried out by using eight voltage vectors, and completes normal variable frequency speed regulation of a motor under the control of two phases while reducing the cost of a frequency converter.

Referring to fig. 1, the three-phase motor control circuit comprises a three-phase power supply, a rectification circuit, a direct current bus circuit, an inversion circuit and a three-phase asynchronous motor, the three-phase power supply, the rectification circuit, the direct current bus circuit, the inversion circuit and the three-phase asynchronous motor are sequentially connected, the output end of the direct current bus circuit is connected with the input end of the inversion circuit, the rectification circuit is a diode uncontrolled rectification circuit,

the direct-current bus circuit comprises a first capacitor C1 and a second capacitor C2, the first capacitor C1 and the second capacitor C2 are connected in series, and the midpoint of the first capacitor C1 and the midpoint of the second capacitor C2 are connected with W of the three-phase asynchronous motor;

the inverter circuit comprises a U-phase inverter circuit and a V-phase inverter circuit;

the U-phase inverter circuit comprises a first thyristor VT1, a second thyristor VT2, an IGBT1, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4 and a third capacitor C3; the cathode of the first thyristor VT1 is respectively connected with the collector of the IGBT1 and the anode of the first diode D1, the anode of the first thyristor VT1 is connected with the cathode of the first diode D1, the anode of the second thyristor VT2 is respectively connected with the emitter of the IGBT1 and the cathode of the second diode D2, the cathode of the second thyristor VT2 is connected with the anode of the second diode D2, a third capacitor C3 is connected in parallel between the collector and the emitter of the IGBT1, the U of the three-phase asynchronous motor is connected between the third diode D3 and the fourth diode D4,

the V-phase inverter circuit comprises a third thyristor VT3, a fourth thyristor VT4, an IGBT2, a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8 and a fourth capacitor C4, wherein the cathode of the third thyristor VT3 is respectively connected with the collector of the IGBT2 and the anode of the fifth diode D5, the anode of the third thyristor VT3 is connected with the cathode of the fifth diode D5, the anode of the fourth thyristor VT4 is respectively connected with the emitter of the IGBT2 and the cathode of the sixth diode D6, the cathode of the fourth thyristor VT4 is connected with the anode of the sixth diode D6, the fourth capacitor C4 is connected between the collector and the emitter of the IGBT2 in parallel, and the V phase of the three-phase asynchronous motor is connected between the seventh diode D7 and the eighth diode D8.

Based on the three-phase motor control circuit, by defining a voltage space vector under the condition of conduction, referring to fig. 2, the voltage vector is specifically defined as follows:

establishing an alpha-beta coordinate system, defining that the A phase voltage vector of the three-phase asynchronous motor is in a 90-degree direction, the B phase voltage vector is in a-150-degree direction, and the C phase voltage vector is in a-30-degree direction, wherein the voltage vectors of all possible conduction states are eight and are respectively defined as a voltage vector U1, a voltage vector U2, a voltage vector U3, a voltage vector U4, a voltage vector U5, a voltage vector U6, a voltage vector U7 and a voltage vector U8;

the states of the first thyristor VT1, the second thyristor VT2, the third thyristor VT3, and the fourth thyristor VT4 are recorded as four-bit codes (abcd), a, b, c, and d sequentially correspond to the first thyristor VT1, the second thyristor VT2, the third thyristor VT3, and the fourth thyristor VT4, and a value 1 represents that the corresponding thyristor is in a conducting state, and a value 0 represents that the corresponding thyristor is in a blocking state, so that the voltage vector U1, the voltage vector U2, the voltage vector U3, the voltage vector U4, the voltage vector U5, the voltage vector U6, the voltage vector U7, and the voltage vector U8 sequentially correspond to U1 (0001), U2 (1001), U3 (1000), U4 (1010), U5 (0010), U6 (0110), U7 (0100), and U8 (0101).

Voltage vector U1: at this time, the IGBTs 2 and VT4 in fig. 1 are turned on, the current flows out from the neutral point of the dc bus, flows in through the phase C of the electric motor, flows out through the phase B, and then flows into the negative terminal of the capacitor C2 through the diode D7, the IGBTs 2 and VT4, since only the voltage of the motor terminal is half of the bus voltage at this time when the C2 is used.

Voltage vector U2: at this time, VT1 and IGBT1, VT4 and IGBT2 in fig. 1 are turned on, and the current flows out from the positive electrode of the capacitor C1, flows through the motor a phase through VT1 and IGBT1, and diode D4, flows into the motor B phase, and flows into the negative terminal of the capacitor C2 through diodes D7, VT4, and IGBT2, and the voltage of the motor terminal is the voltage of the entire bus bar at this time.

Voltage vector U3: at this time, VT1 and IGBT1 in fig. 1 are turned on, and current flows from the positive electrode of capacitor C1 through VT1 and IGBT1 into phase a, flows out from phase C, and finally enters the neutral point, where the magnitude of the terminal voltage of the motor is half of the bus voltage.

Voltage vector U4: at this time, VT1 and IGBT1, VT3 and IGBT2 in fig. 1 are turned on, and current flows from the positive electrode of capacitor C1 through VT1 and IGBT1 and D4, VT3 and IGBT2 and D8 through phase a and phase B, and flows out to the neutral point through phase C, and the magnitude of the terminal voltage of the motor at this time is half of the bus voltage.

Voltage vector U5: at this time, the IGBTs 1 and VT3 in fig. 1 are turned on, the current flows into the B phase from the positive electrode of the capacitor C1 through the IGBTs 1, VT3, and D8, the C phase flows out, and finally enters the neutral point, and the voltage of the motor terminal at this time is half of the bus voltage.

Voltage vector U6: at this time, IGBTs 2 and VT3 in fig. 1 are turned on, and a current flows from the positive electrode of capacitor C1 through IGBTs 2 and VT3 into phase B and flows out from phase a. The voltage of the motor terminal at the moment is the voltage of the whole bus bar after entering the negative end of the capacitor C2 through the IGBT1, the VT2 and the D3. When the A phase and the B phase are conducted at the same time, the motor is subjected to twice bus voltage.

Voltage vector U7: at the moment, the IGBTs 1 and VT2 in fig. 1 are turned on, the current flows out from the neutral point of the dc bus, flows in through the phase C of the motor, flows out through the phase a, and finally enters the negative terminal of the capacitor C2 through the IGBTs 1 and VT2, and the voltage of the motor terminal at the moment is half of the bus voltage.

Voltage vector U8: at the moment, the IGBTs 1 and VT2 and the IGBTs 2 and VT4 in fig. 1 are turned on, the current flows out from the neutral point of the dc bus, enters the phase C, and finally flows into the negative terminal of the capacitor C2 through the phase a and the phase B, and the voltage of the motor terminal is half of the bus voltage at the moment.

The complex plane is divided into 8 sectors by the 8 voltage vectors, referring to fig. 3, the sectors are represented by θ (k), where k is a sector number, and the electrical angle occupied by each sector in the four-switch inverter control system is different; the purpose of dividing the sectors is mainly to design vectors to efficiently control flux linkage and torque, and the influence on flux linkage is different when the same voltage vector is located in different sectors. In the same sector, the influence on flux linkage under the condition of voltage vector change is different. As can be seen from the above discussion, the number of voltage space vectors of this topology is 8, and there is a complex variation in the corresponding amplitudes, and it is also asymmetric. In the mode, the complex plane is divided into 8 sectors by 8 inherent voltage vectors, and the occupied angles of the sectors are different.

Referring to fig. 4, flux linkage adjustment command ψ obtained by the hysteresis adjustment unit _Q And torque adjustment command T _Q And selecting a proper switching signal to control the inverter by setting a voltage vector selection table according to the sector theta (k) where the current flux linkage is located.

Taking θ (1) sector as an example, and assuming that the flux linkage rotates counterclockwise, then:

when psi _Q ＝1，T _Q =1, indicating that stator flux linkage needs to be increased, electromagnetic torque needs to be increased, and voltage vector V is selected ₁ ；

When psi _Q ＝1，T _Q =0, indicating that stator flux linkage needs to be increased, electromagnetic torque needs to be reduced, and voltage vector V is selected ₈ ；

When psi _Q ＝0，T _Q =1, indicate that stator flux linkage needs to be reduced, electromagnetic torque needs to be increased, and voltage vector V is selected ₄ ；

When psi _Q ＝0，T _Q =0, indicating that stator flux linkage needs to be reduced, electromagnetic torque needs to be reduced, and selecting voltage vector V ₆ ；

The same applies to other sectors, the voltage vector selection table can be obtained as follows:

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the above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only examples of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (4)

1. The two-phase eight-vector direct torque control method of the three-phase motor control circuit is characterized by comprising the following steps of:

the three-phase motor control circuit comprises a three-phase power supply, a rectifying circuit, a direct current bus circuit, an inverter circuit and a three-phase asynchronous motor, the three-phase power supply, the rectifying circuit, the direct current bus circuit, the inverter circuit and the three-phase asynchronous motor are sequentially connected, the output end of the direct current bus circuit is connected with the input end of the inverter circuit, the rectifying circuit is a diode uncontrolled rectifying circuit,

the direct-current bus circuit comprises a first capacitor C1 and a second capacitor C2, the first capacitor C1 and the second capacitor C2 are connected in series, and the midpoint of the first capacitor C1 and the midpoint of the second capacitor C2 are connected with W of the three-phase asynchronous motor;

the inverter circuit comprises a U-phase inverter circuit and a V-phase inverter circuit;

the U-phase inverter circuit comprises a first thyristor VT1, a second thyristor VT2, an IGBT1, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4 and a third capacitor C3; the cathode of the first thyristor VT1 is respectively connected with the collector of the IGBT1 and the anode of the first diode D1, the anode of the first thyristor VT1 is connected with the cathode of the first diode D1, the anode of the second thyristor VT2 is respectively connected with the emitter of the IGBT1 and the cathode of the second diode D2, the cathode of the second thyristor VT2 is connected with the anode of the second diode D2, a third capacitor C3 is connected in parallel between the collector and the emitter of the IGBT1, the U of the three-phase asynchronous motor is connected between the third diode D3 and the fourth diode D4,

the V-phase inverter circuit comprises a third thyristor VT3, a fourth thyristor VT4, an IGBT2, a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8 and a fourth capacitor C4, wherein the cathode of the third thyristor VT3 is respectively connected with the collector of the IGBT2 and the anode of the fifth diode D5, the anode of the third thyristor VT3 is connected with the cathode of the fifth diode D5, the anode of the fourth thyristor VT4 is respectively connected with the emitter of the IGBT2 and the cathode of the sixth diode D6, the cathode of the fourth thyristor VT4 is connected with the anode of the sixth diode D6, a fourth capacitor C4 is connected between the collector and the emitter of the IGBT2 in parallel, and the V phase of the three-phase asynchronous motor is connected between the seventh diode D7 and the eighth diode D8;

based on the three-phase motor control circuit, sector division is carried out again by defining voltage space vectors under the conduction condition, including selection of the voltage vectors under different conditions, and the conduction process of the circuit under the topological structure is optimized.

2. The two-phase eight-vector direct torque control method of the three-phase motor control circuit according to claim 1, characterized in that:

the voltage vector is specifically defined as follows:

establishing an alpha-beta coordinate system, defining that the A phase voltage vector of the three-phase asynchronous motor is in a 90-degree direction, the B phase voltage vector is in a-150-degree direction, and the C phase voltage vector is in a-30-degree direction, wherein the voltage vectors of all possible conduction states are eight and are respectively defined as a voltage vector U1, a voltage vector U2, a voltage vector U3, a voltage vector U4, a voltage vector U5, a voltage vector U6, a voltage vector U7 and a voltage vector U8;

defining a voltage vector U1 as a voltage vector when the IGBT2 and the fourth thyristor VT4 are conducted simultaneously; defining a voltage vector U2 as a voltage vector when the IGBT1 and the first thyristor VT1 as well as the IGBT2 and the fourth thyristor VT4 are conducted simultaneously; defining a voltage vector U3 as a voltage vector when the IGBT1 and the first thyristor VT1 are conducted simultaneously; defining a voltage vector U4 as a voltage vector when the IGBT1, the first thyristor VT1, the IGBT2 and the third thyristor VT3 are conducted simultaneously; defining a voltage vector U5 as a voltage vector when the IGBT2 and the third thyristor VT3 are simultaneously conducted; defining a voltage vector U6 as a voltage vector when the IGBT1 and the second thyristor VT2 as well as the IGBT2 and the third thyristor VT3 are simultaneously conducted; defining a voltage vector U7 as a voltage vector when the IGBT1 and the second thyristor VT2 are conducted simultaneously; the voltage vector U8 is defined as a voltage vector when the IGBT1 and the second thyristor VT2 and the IGBT2 and the fourth thyristor VT4 are turned on simultaneously.

3. The two-phase eight-vector direct torque control method of the three-phase motor control circuit according to claim 2, characterized in that:

the 8 voltage vectors divide the complex plane to form 8 sectors, the sectors are represented by theta (k), wherein k is the sector number, and the electrical angle occupied by each sector in the four-switch inverter control system is different; flux linkage adjustment command psi obtained by hysteresis loop adjustment unit _Q And a torque adjustment command T _Q And a voltage vector selection table is arranged in a sector theta (k) where the current flux linkage is located, and an appropriate switching signal is selected to control the inverter.

4. The two-phase eight-vector direct torque control method of the three-phase motor control circuit according to claim 3, characterized in that:

taking θ (1) sector as an example, and assuming that the flux linkage rotates counterclockwise, then:

when psi _Q ＝1，T _Q =1, indicating that stator flux linkage needs to be increased, electromagnetic torque needs to be increased, and voltage vector V is selected ₁ ；

When psi _Q ＝1，T _Q =0, indicating that stator flux linkage needs to be increased, electromagnetic torque needs to be reduced, and selecting a voltage vector V ₈ ；

When psi _Q ＝0，T _Q =1, indicating that stator flux linkage needs to be reduced, electromagnetic torque needs to be increased, and voltage vector V is selected ₄ ；

When psi _Q ＝0，T _Q =0, indicating that stator flux linkage needs to be reduced, electromagnetic torque needs to be reduced, and voltage vector V is selected ₆ ；

The same applies to other sectors, and the voltage vector selection table can be obtained as follows:

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