CN114268260A

CN114268260A - Motor parameter identification method and device

Info

Publication number: CN114268260A
Application number: CN202210196983.5A
Authority: CN
Inventors: 徐晖; 黄晓艳; 吴美飞
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2022-03-02
Filing date: 2022-03-02
Publication date: 2022-04-01
Anticipated expiration: 2042-03-02
Also published as: CN114268260B

Abstract

The application discloses a motor parameter identification method, which comprises the following steps: sequentially controlling the inverter to conduct any two-phase bridge arm according to a first preset conduction mode and a second preset conduction mode, applying a forward voltage pulse to a winding of the permanent magnet synchronous motor in the first preset conduction mode, and applying a reverse voltage pulse to the winding of the permanent magnet synchronous motor in the second preset conduction mode; acquiring direct-current bus voltage under a forward voltage pulse, and acquiring a first current value and a second current value of a corresponding winding on a conducting bridge arm at different moments under the forward voltage pulse; and calculating the quadrature axis inductance parameter and the direct axis inductance parameter according to the direct current bus voltage under the forward voltage pulse, the first current value, the second current value and the current acquisition time interval. The application also provides a motor parameter identification device, under the condition of unknown motor inductance parameters, the motor can be very simply and conveniently identified before operation.

Description

Motor parameter identification method and device

Technical Field

The invention relates to the technical field of motor control, in particular to a motor parameter identification method and device.

Background

Permanent Magnet Synchronous Motors (PMSM) have the advantages of high power density, wide speed regulation range, high efficiency, small volume, fast response, reliable operation and the like, and are widely applied to alternating current driving occasions such as household appliances, numerical control machine tools, industrial robots, electric automobiles, aviation equipment and the like.

The vector control algorithm of the motor has strong dependence on the parameters of the motor, wherein the inductance is the most important parameter, and the parameter is changed along with the current. The accurate inductance parameter is obtained, and the method plays an important role in improving the control efficiency of the motor, accurately estimating the rotating speed of the motor, controlling the precision of a current loop, controlling weak magnetism and the like.

The existing method for identifying the offline parameters of the permanent magnet synchronous motor is to apply different forms of voltage and current excitation to the motor before the permanent magnet synchronous motor runs, detect corresponding voltage and current responses of the permanent magnet synchronous motor, and obtain motor parameters according to the relationship between the excitation, the responses and the motor parameters, or identify the motor parameters by adopting a certain fitting algorithm.

For example, applying a direct current to the motor positions the rotor on the d-axis, and then applying a sinusoidal excitation, the response is detected. However, the attraction of the permanent magnet rotor to the stator teeth and slots causes the rotor to shift after positioning, and if the positioning current is increased to prevent the shift, the magnetic path is easily saturated, and the accuracy of identification is easily lowered. In addition, after the rotor is positioned, when sinusoidal excitation is applied, the rotor may shake and deviate from the d axis, so that the identification precision is reduced, and the quadrature axis inductance parameter Lq cannot be accurately identified.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a method and an apparatus for identifying motor parameters, which can improve the accuracy of identifying motor parameters.

According to a first aspect of the present invention, there is provided a motor parameter identification method, including: sequentially controlling an inverter to conduct any two phase bridge arms according to a first preset conduction mode and a second preset conduction mode, disconnecting a third phase bridge arm, applying forward voltage pulses to a winding of the permanent magnet synchronous motor in the first preset conduction mode, and applying reverse voltage pulses to the winding of the permanent magnet synchronous motor in the second preset conduction mode; acquiring direct-current bus voltage under a forward voltage pulse, and acquiring a first current value and a second current value of a corresponding winding on a conducting bridge arm at different moments under the forward voltage pulse, wherein a time interval between the different moments is a current acquisition time interval; calculating quadrature axis inductance parameters and direct axis inductance parameters according to the direct current bus voltage under the forward voltage pulse, the first current value, the second current value and the current acquisition time interval; the first preset mode is that an upper bridge arm of a first phase of the two phases is conducted with a lower bridge arm of a second phase of the two phases; the second preset mode is that the lower bridge arm of the first phase of the two phases is communicated with the upper bridge arm of the second phase of the two phases; the action directions of the forward voltage pulse and the reverse voltage pulse are opposite.

Preferably, sequentially controlling the inverter to conduct any two phase bridge arms according to a first preset conduction mode and a second preset conduction mode, and disconnecting the third phase bridge arm, wherein in the first preset conduction mode, applying a forward voltage pulse to the winding of the permanent magnet synchronous motor, and in the second preset conduction mode, applying a reverse voltage pulse to the winding of the permanent magnet synchronous motor includes: switching on a first-phase upper bridge arm and a second-phase lower bridge arm in the inverter, switching off the first-phase lower bridge arm, the second-phase upper bridge arm, a third-phase upper bridge arm and a third-phase lower bridge arm in the inverter, and applying a first voltage pulse with the duration of first preset time to a winding of the permanent magnet synchronous motor; switching on a first-phase lower bridge arm and a second-phase upper bridge arm in the inverter, switching off the first-phase upper bridge arm, the second-phase lower bridge arm, a third-phase upper bridge arm and a third-phase lower bridge arm in the inverter, and applying a second voltage pulse with the duration of a second preset time to a winding of the permanent magnet synchronous motor; switching on a second-phase upper bridge arm and a third-phase lower bridge arm in the inverter, switching off the second-phase lower bridge arm, the third-phase upper bridge arm, the first-phase upper bridge arm and the first-phase lower bridge arm in the inverter, and applying a third voltage pulse with the duration of third preset time to a winding of the permanent magnet synchronous motor; switching on a second-phase lower bridge arm and a third-phase upper bridge arm in the inverter, switching off the second-phase upper bridge arm, the third-phase lower bridge arm, the first-phase upper bridge arm and the first-phase lower bridge arm in the inverter, and applying a fourth voltage pulse with the duration of fourth preset time to a winding of the permanent magnet synchronous motor; switching on a third-phase upper bridge arm and a first-phase lower bridge arm in the inverter, switching off the third-phase lower bridge arm, the first-phase upper bridge arm, the second-phase upper bridge arm and the second-phase lower bridge arm in the inverter, and applying a fifth voltage pulse with the duration of fifth preset time to a winding of the permanent magnet synchronous motor; and switching on a third-phase lower bridge arm and a first-phase upper bridge arm in the inverter, switching off the third-phase upper bridge arm, the first-phase lower bridge arm, the second-phase upper bridge arm and the second-phase lower bridge arm in the inverter, and applying a sixth voltage pulse with the duration of sixth preset time to a winding of the permanent magnet synchronous motor.

Preferably, when the three-phase winding current of the permanent magnet synchronous motor is zero and the rotor is in a static state, a positive voltage pulse is applied to the winding of the permanent magnet synchronous motor.

Preferably, after applying the reverse voltage pulse to the winding of the permanent magnet synchronous motor, the permanent magnet synchronous motor is allowed to stand for a certain time to make the three-phase winding current of the permanent magnet synchronous motor zero and make the rotor in a static state.

Preferably, the acquiring the dc bus voltage under the forward voltage pulse, and the acquiring the first current value and the second current value of the corresponding winding on the conducting bridge arm at different times under the forward voltage pulse include: collecting the direct current bus voltage in the continuous process of the first voltage pulse, the third voltage pulse and the fifth voltage pulse to obtain a first bus voltage, a second bus voltage and a third bus voltage; collecting a first line current and a second line current at different moments in the first voltage pulse duration process, collecting a third line current and a fourth line current at different moments in the third voltage pulse duration process, and collecting a fifth line current and a sixth line current at different moments in the fifth voltage pulse duration process; the time interval between the different moments is set time.

Preferably, the calculating the quadrature axis inductance parameter and the direct axis inductance parameter according to the dc bus voltage under the forward voltage pulse, the first current value, the second current value, and the current collection time interval includes: calculating the difference value of the first line current and the second line current to obtain a first current difference value;calculating the difference value of the third line current and the fourth line current to obtain a second current difference value; calculating a difference value between the fifth line current and the sixth line current to obtain a third current difference value; calculating to obtain a line-line inductance L between the first phase and the second phase according to a formula U = L delta i/delta t, the first bus voltage, the second bus voltage, the third bus voltage, the first current difference, the second current difference, the third current difference and the current acquisition time interval₁₂Line-to-line inductance L between the second and third phases₂₃And a line-to-line inductance L between the third phase and the first phase₃₁(ii) a Based on line-to-line inductance L between the first and second phases₁₂Line-to-line inductance L between the second and third phases₂₃And a line-to-line inductance L between the third phase and the first phase₃₁And formulas

，

，

，

，

，

，

，

And calculating to obtain quadrature axis inductance parameters and direct axis inductance parameters of the permanent magnet synchronous motor.

Preferably, the first voltage pulse and the second voltage pulse act in opposite directions; the third voltage pulse and the fourth voltage pulse have opposite action directions, and the fifth voltage pulse and the sixth voltage pulse have opposite action directions.

Preferably, the first preset time is equal to the second preset time; the third preset time is equal to the fourth preset time; the fifth preset time is equal to the sixth preset time.

Preferably, the identification method further comprises: integrating and averaging the direct current bus voltage detected under the first voltage pulse within a first preset time to obtain a first bus voltage, and sampling currents at different moments within the first preset time to obtain a first line current and a second line current; integrating and averaging the direct-current bus voltage detected under the third voltage pulse within a third preset time to obtain a second bus voltage, and sampling currents at different moments within the third preset time to obtain a third line current and a fourth line current; and integrating and averaging the direct current bus voltage detected under the fifth voltage pulse within a fifth preset time to obtain a third bus voltage, and sampling currents at different moments within the fifth preset time to obtain a fifth line current and a sixth line current.

According to another aspect of the present invention, there is provided a motor parameter identification device, including: a pulse signal generator for generating a pulse signal; the control module is connected with the pulse signal generator and is used for controlling the pulse signal generator to sequentially generate pulse signals; the inverter is connected between the pulse generator and the permanent magnet synchronous motor and used for sequentially controlling the inverter to conduct any two phase bridge arms according to a first preset conduction mode and a second preset conduction mode according to the pulse signal and disconnect a third phase bridge arm, forward voltage pulses are applied to a winding of the permanent magnet synchronous motor in the first preset conduction mode, and reverse voltage pulses are applied to the winding of the permanent magnet synchronous motor in the second preset conduction mode; the control module is further used for acquiring direct-current bus voltage under the forward voltage pulse, and acquiring a first current value and a second current value of a corresponding winding on a conducting bridge arm at different moments under the forward voltage pulse, wherein a time interval between the different moments is a current acquisition time interval; the inductance calculation module is used for calculating quadrature axis inductance parameters and direct axis inductance parameters according to the direct current bus voltage under the forward voltage pulse, the first current value, the second current value and the current acquisition time interval; the first preset mode is that an upper bridge arm of a first phase of the two phases is conducted with a lower bridge arm of a second phase of the two phases; the second preset mode is that the lower bridge arm of the first phase of the two phases is communicated with the upper bridge arm of the second phase of the two phases; the action directions of the forward voltage pulse and the reverse voltage pulse are opposite.

Preferably, the control module comprises: the first control unit is used for controlling the pulse signal generator to generate a first pulse signal and a second pulse signal; the second control unit is used for controlling the pulse signal generator to generate a third pulse signal and a fourth pulse signal; the third control unit is used for controlling the pulse signal generator to generate a fifth pulse signal and a sixth pulse signal, wherein the first pulse signal is used for conducting a first-phase upper bridge arm and a second-phase lower bridge arm in the inverter, disconnecting the first-phase lower bridge arm, the second-phase upper bridge arm, a third-phase upper bridge arm and a third-phase lower bridge arm in the inverter, and applying a first voltage pulse with the duration of first preset time to a winding of the permanent magnet synchronous motor; the second pulse signal is used for conducting a first-phase lower bridge arm and a second-phase upper bridge arm in the inverter, disconnecting the first-phase upper bridge arm, the second-phase lower bridge arm, a third-phase upper bridge arm and a third-phase lower bridge arm in the inverter, and applying a second voltage pulse with the duration of a second preset time to a winding of the permanent magnet synchronous motor; the third pulse signal is used for conducting a second-phase upper bridge arm and a third-phase lower bridge arm in the inverter, disconnecting the second-phase lower bridge arm, the third-phase upper bridge arm, the first-phase upper bridge arm and the first-phase lower bridge arm in the inverter, and applying a third voltage pulse with the duration of a third preset time to a winding of the permanent magnet synchronous motor; the fourth pulse signal is used for conducting a second-phase lower bridge arm and a third-phase upper bridge arm in the inverter, disconnecting the second-phase upper bridge arm, the third-phase lower bridge arm, the first-phase upper bridge arm and the first-phase lower bridge arm in the inverter, and applying a fourth voltage pulse with the duration of fourth preset time to a winding of the permanent magnet synchronous motor; the fifth pulse signal is used for conducting a third phase upper bridge arm and a first phase lower bridge arm in the inverter, disconnecting the third phase lower bridge arm, the first phase upper bridge arm, the second phase upper bridge arm and the second phase lower bridge arm in the inverter, and applying a fifth voltage pulse with the duration of fifth preset time to a winding of the permanent magnet synchronous motor; and the sixth pulse signal switches on a third-phase lower bridge arm and a first-phase upper bridge arm in the inverter, switches off the third-phase upper bridge arm, the first-phase lower bridge arm, the second-phase upper bridge arm and the second-phase lower bridge arm in the inverter, and applies a sixth voltage pulse with the duration of sixth preset time to a winding of the permanent magnet synchronous motor.

Preferably, the control module is further configured to control the pulse signal generator to generate a forward pulse signal when the current of the three-phase winding of the permanent magnet synchronous motor is zero and the rotor is in a stationary state, and the inverter applies a forward voltage pulse to the winding of the permanent magnet synchronous motor according to the forward pulse signal.

Preferably, after the inverter applies a reverse voltage pulse to the winding of the permanent magnet synchronous motor, the permanent magnet synchronous motor is allowed to stand for a certain time to make the three-phase winding current of the permanent magnet synchronous motor zero and make the rotor in a static state.

Preferably, the control module further comprises: the first detection unit is used for acquiring the direct-current bus voltage in the continuous process of the first voltage pulse, the third voltage pulse and the fifth voltage pulse to obtain a first bus voltage, a second bus voltage and a third bus voltage; collecting a first line current and a second line current at different moments in the first voltage pulse duration process, collecting a third line current and a fourth line current at different moments in the third voltage pulse duration process, and collecting a fifth line current and a sixth line current at different moments in the fifth voltage pulse duration process; the time interval between the different moments is set time.

Preferably, the inductance calculation module is further configured to calculate a difference between the first line current and the second line current to obtain a first current difference; calculating the difference value of the third line current and the fourth line current to obtain a second current difference value; calculating a difference value between the fifth line current and the sixth line current to obtain a third current difference value; the inductance calculation module is further used for calculating the inductance of the first bus according to the formula U = LCalculating the voltage, the second bus voltage, the third bus voltage, the first current difference, the second current difference, the third current difference and the current acquisition time interval to obtain the line-line inductance L between the first phase and the second phase of the permanent magnet synchronous motor₁₂Line-to-line inductance L between the second and third phases₂₃And a line-to-line inductance L between the third phase and the first phase₃₁(ii) a The inductance calculation module is also used for calculating the inductance according to a formula

，

，

，

，

，

，

，

Preferably, the first detecting unit is further configured to integrate and average the dc bus voltage detected under the first voltage pulse within a first preset time to obtain a first bus voltage, and sample currents at different times within the first preset time to obtain a first line current and a second line current; the first detection unit is further configured to integrate and average the dc bus voltage detected under the third voltage pulse within a third preset time to obtain a second bus voltage, and sample currents at different times within the third preset time to obtain a third line current and a fourth line current; the first detection unit is further configured to integrate the dc bus voltage detected under the fifth voltage pulse within a fifth preset time, average the integrated dc bus voltage to obtain a third bus voltage, and sample currents at different times within the fifth preset time to obtain a fifth line current and a sixth line current.

According to the motor parameter identification method and device provided by the invention, when the permanent magnet synchronous motor is in a state that the three-phase winding current is zero and the rotor is static, a forward voltage pulse is sequentially applied to any two-phase bridge arm by the permanent magnet synchronous motor, and the line-line inductance between three two phases is calculated by detecting the current of the permanent magnet synchronous motor under the action of the forward voltage pulse; and further calculating the direct axis inductance parameter according to a theoretical formulaL _dAnd quadrature axis inductance parameterL _q. Under the condition of unknown motor inductance parameters, the method can identify the inductance parameters very simply and conveniently before the motor runs, does not need external equipment to fix the rotating shaft of the permanent magnet synchronous motor, does not need a rotor stalling experiment, and can realize the direct-axis inductance parametersL _dAnd quadrature axis inductance parameterL _qThe method is simple and convenient, easy to realize and capable of improving the identification precision.

Further, two-phase bridge arms are conducted according to a first preset mode, and positive voltage pulses are applied to a winding of the permanent magnet synchronous motor; switching on the two-phase bridge arms according to a second preset mode, and applying reverse voltage pulse to a winding of the permanent magnet synchronous motor; the first preset conduction mode is that one phase of upper bridge arm is conducted with the other phase of lower bridge arm; the second preset conduction mode is that one phase of lower bridge arm is conducted with the other phase of upper bridge arm; the positive voltage pulse and the reverse voltage pulse have opposite action directions, equal amplitude and equal action time, so that the action force acting on the motor rotor is 0, the inductance parameter identification error caused by rotor displacement is reduced to the maximum extent, and the identification precision is improved.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

fig. 1 shows a spatial relationship diagram of rotor poles of a permanent magnet synchronous machine;

FIG. 2 is a graph showing a self-inductance parameter versus rotor position angle for any phase of a PMSM;

FIG. 3 is a graph illustrating a mutual inductance parameter between two phases of a PMSM as a function of rotor position angle;

fig. 4 is a flowchart illustrating a motor parameter identification method according to an embodiment of the present invention;

fig. 5 is a flowchart illustrating step S100 of a motor parameter identification method according to an embodiment of the present invention;

fig. 6 is a flowchart illustrating step S300 of the motor parameter identification method according to the embodiment of the present invention;

fig. 7 is a schematic structural diagram illustrating a motor parameter identification device according to an embodiment of the present invention;

fig. 8 shows a schematic diagram of a control unit provided by an embodiment of the present invention.

Detailed Description

Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples.

Fig. 1 shows a spatial relationship diagram of rotor poles of a permanent magnet synchronous machine; FIG. 2 is a graph showing a self-inductance parameter versus rotor position angle for any phase of a PMSM; fig. 3 shows a graph of mutual inductance parameter between two phases of a permanent magnet synchronous motor versus rotor position angle.

N-S is a permanent magnet of the permanent magnet synchronous motor, the permanent magnet rotor rotates to generate an alternating magnetic field in space, the magnetic field is linked with the three-phase winding in an intersecting manner to induce back electromotive force, and at the moment, the rotor magnetic field synchronously rotates along with the stator rotating magnetic field under the action of the pulling force of the stator magnetic field.

The ABC coordinate system represents a three-phase stator coordinate system, the three-phase winding axes A, B, C of the three-phase alternating current motor are spatially different from each other by an electrical angle of 2 pi/3 rad, and the projection of a space vector on the three coordinate axes is represented as the component of the space vector on the three windings; the d axis of the horizontal axis of the d-q coordinate system is at the same position with the N magnetic pole of the permanent magnet rotor, the q axis of the vertical axis of the d-q coordinate system leads the d axis of the horizontal axis by 90 electrical degrees anticlockwise, the coordinate system and the permanent magnet rotor rotate synchronously in space, and the d-q coordinate system is also called as a rotating coordinate system.

When the permanent magnet rotor and the stator rotating magnetic field keep synchronous rotation, an included angle between a horizontal axis d (namely a rotor N pole) of a rotating coordinate system and an axis A of a three-phase stator coordinate system ABC is defined as a position angle theta of the rotor.

Under a three-phase stator coordinate system, an inductance matrix of a Permanent Magnet Synchronous Motor (PMSM) is as follows:

(1)

in the formula:

the self-inductance of the A phase is obtained,

the self-inductance of the B phase is obtained,

self-inductance of phase C;

、

is A, B mutual inductance between the two phases,

、

is A, C mutual inductance between the two phases,

、

b, C is a mutual inductance of the two phases.

Self-inductance by phase A

For example (see fig. 2), when the permanent magnet rotor is orthogonal to the a-axis, i.e.

Or

When the magnetic resistance is the largest, the corresponding magnetic resistance is the largest,

reaches a minimum value, is recorded as

(ii) a When the permanent magnet rotor is coincident with the A-axis, i.e. when the permanent magnet rotor is coincident with the A-axis

Or

When the corresponding reluctance is minimal, i.e.

Reaches a maximum value, is recorded as

+

(ii) a The calculation formula for the three-phase self-inductance is therefore:

(2)

as can be seen from the formula (2),

to be provided with

Is a period following the angle between the permanent magnet rotor and the A axis

The change of (2) is sinusoidal and the value is constant positive.

Mutual inductance between phases of the stator is also dependent on the position of the rotor, and

the period of the permanent magnet rotor is changed in a sine way, taking the mutual inductance between A and B phases as an example (see figure 3), when the permanent magnet rotor lags behind the A axis

Or lead

When the temperature of the water is higher than the set temperature,

reaching a maximum value; when in

Or

When the temperature of the water is higher than the set temperature,

a minimum value is reached. Similarly, the A, B and C three-phase windings are mutually different in space

And therefore the mutual inductance value is negative.

Therefore, the calculation formula of the mutual inductance between the three-phase windings is as follows:

(3)

transforming an inductance matrix of an A, B and C three-phase stationary coordinate system shown in formula (1) into a d and q two-phase rotating coordinate system to obtain:

(4)

in the formula:

3s/2s and 2s/2r coordinate transformation matrixes respectively.

Simplifying to obtain:

(5)

therefore, the d and q-axis inductances are respectively:

（6）

generally, a Y-type connection method is adopted for three-phase stator windings of the PMSM, when a motor rotor is static, the position of the motor rotor is random, so d-axis and q-axis inductance parameters cannot be directly obtained through measurement, but d-axis and q-axis inductances can be obtained through calculation through measuring line inductances between every two three-phase windings. As described above, assuming that the three phases C, A and B are open-circuited, the measured line inductance is

，

，

Then there is

（7）

The formulas (2) and (3) are substituted for the formula (7) and simplified to obtain:

(8)

adding the rows in (8) to obtain:

(9)

then order

Simplifying to obtain:

(10)

the calculation can obtain:

(11)

thus:

(12)

to obtain

And

after the value of (2), the value can be calculated according to the formula (6)

And

。

fig. 4 shows a flowchart of a motor parameter identification method according to an embodiment of the present invention. As shown in fig. 4, the motor parameter identification method includes the following steps.

In step S100, the inverter is sequentially controlled to conduct any two-phase bridge arm according to a first preset conduction mode and a second preset conduction mode, and in the first preset conduction mode, a forward voltage pulse is applied to the winding of the permanent magnet synchronous motor, and in the second preset conduction mode, a reverse voltage pulse is applied to the winding of the permanent magnet synchronous motor.

In this embodiment, the first phase is an a phase, the second phase is a B phase, and the third phase is a C phase, but the present invention is not limited thereto. Specifically, two phase bridge arms are conducted according to a first preset conduction mode, a third phase bridge arm is disconnected, and a positive voltage pulse is applied to a winding of the permanent magnet synchronous motor; switching on the two-phase bridge arms according to a second preset switching-on mode, switching off the third phase bridge arm, and applying reverse voltage pulse to a winding of the permanent magnet synchronous motor; the first preset conduction mode is that the upper bridge arm of one phase is conducted with the lower bridge arm of the other phase; the second preset conduction mode is that the lower bridge arm of one phase is conducted with the upper bridge arm of the other phase; the forward voltage pulse and the reverse voltage pulse have opposite action directions and equal amplitudes, and the application time is the same.

In this embodiment, when the three-phase winding current of the permanent magnet synchronous motor is zero and the rotor is in a stationary state, a positive voltage pulse is applied to the winding of the permanent magnet synchronous motor. And after applying reverse voltage pulse to the winding of the permanent magnet synchronous motor, standing for a certain time to enable the current of the three-phase winding of the permanent magnet synchronous motor to be zero and the rotor to be in a static state.

Taking the example of conducting the first phase and the second phase bridge arm as an example, the first preset mode is to control the conduction of the first phase upper bridge arm and the second phase lower bridge arm, and the second preset mode is to control the conduction of the first phase lower bridge arm and the second phase upper bridge arm.

Specifically, referring to FIG. 5, step S100 includes steps S110-S160.

In step S110, when the current of the three-phase winding of the permanent magnet synchronous motor is zero and the rotor is in a static state, the first-phase upper arm and the second-phase lower arm of the inverter are turned on, the first-phase lower arm, the second-phase upper arm, the third-phase upper arm and the third-phase lower arm of the inverter are turned off, and the first voltage pulse V1 with the duration of the first preset time t1 is applied to the winding of the permanent magnet synchronous motor.

In step S120, the lower arm and the upper arm of the first phase in the inverter are turned on, the lower arm, the upper arm and the lower arm of the third phase in the inverter are turned off, and a second voltage pulse V2 with a duration of a second preset time t2 is applied to the winding of the permanent magnet synchronous motor. After the second voltage pulse V2 is applied, the permanent magnet synchronous motor is left standing for a certain time to make the three-phase winding current of the permanent magnet synchronous motor zero and make the rotor in a static state.

In step S130, when the current of the three-phase winding of the permanent magnet synchronous motor is zero and the rotor is in a static state, the second-phase upper arm and the third-phase lower arm of the inverter are turned on, the second-phase lower arm, the third-phase upper arm, the first-phase upper arm and the first-phase lower arm of the inverter are turned off, and a third voltage pulse V3 with a duration of a third preset time t3 is applied to the winding of the permanent magnet synchronous motor.

In step S140, the second phase lower arm and the third phase upper arm of the inverter are turned on, the second phase upper arm, the third phase lower arm, the first phase upper arm and the first phase lower arm of the inverter are turned off, and a fourth voltage pulse V4 with a duration of a fourth preset time t4 is applied to the winding of the permanent magnet synchronous motor. After the fourth voltage pulse V4 is applied, the permanent magnet synchronous motor is left standing for a certain time to make the three-phase winding current of the permanent magnet synchronous motor zero and make the rotor in a static state.

In step S150, when the current of the three-phase winding of the permanent magnet synchronous motor is zero and the rotor is in a static state, the third-phase upper arm and the first-phase lower arm of the inverter are turned on, the third-phase lower arm, the first-phase upper arm, the second-phase upper arm and the second-phase lower arm of the inverter are turned off, and a fifth voltage pulse V5 with a duration of a fifth preset time t5 is applied to the winding of the permanent magnet synchronous motor.

In step S160, the third phase lower arm and the first phase upper arm of the inverter are turned on, the third phase upper arm, the first phase lower arm, the second phase upper arm and the second phase lower arm of the inverter are turned off, and a sixth voltage pulse V6 with a duration of sixth preset time t6 is applied to the winding of the permanent magnet synchronous motor. After the sixth voltage pulse V6 is applied, the permanent magnet synchronous motor is left standing for a certain time to make the three-phase winding current of the permanent magnet synchronous motor zero and make the rotor in a static state.

In the present embodiment, the first voltage pulse V1 and the second voltage pulse V2 act in opposite directions; the third voltage pulse V3 and the fourth voltage pulse V4 act in opposite directions, and the fifth voltage pulse V5 and the sixth voltage pulse V6 act in opposite directions. The first preset time t1 is equal to the second preset time t 2; the third preset time t3 is equal to the fourth preset time t 4; the fifth preset time t5 is equal to the sixth preset time t 6.

In step S200, a dc bus voltage under the forward voltage pulse is obtained, and a first current value and a second current value of a corresponding winding on the conducting bridge arm are collected at different times under the forward voltage pulse, where a time interval between the different times is a current collection time interval.

In this embodiment, the dc bus voltage and the current under the first voltage pulse, the third voltage pulse and the fifth voltage pulse are respectively sampled, and the first bus voltage Vdc1, the second bus voltage Vdc2, the third bus voltage Vdc3 and the first line current I are calculated₁A second line current I₂A third line current I₃Fourth line current I₄A fifth line current I₅And a sixth line current I₆. Wherein the first line current I₁And a second line current I₂Line currents Iab at different moments respectively; third line current I₃And a fourth line current I₄Line current Ibc at different times respectively; fifth line current I₅And a sixth line current I₆Respectively line current Iac at different times.

Specifically, the direct-current bus voltage and the direct-current bus current under the first voltage pulse V1 are sampled, and the first bus voltage Vdc1 and the first line current I are calculated₁And a second line current I₂(ii) a Sampling the direct current bus voltage and current under the third voltage pulse V3, and calculating to obtain a second bus voltage Vdc2 and a third line current I₃And a fourth line current I₄(ii) a Sampling the direct-current bus voltage and current under the fifth voltage pulse V5, and calculating to obtain a third bus voltage Vdc3 and a fifth line current I₅And a sixth line current I₆。

In the present embodiment, the dc bus voltage detected under the first voltage pulse V1 is integrated and averaged over the first preset time t1 to obtain the first bus voltage Vdc 1; and sampling the current at different moments in time t1 within a first preset time to obtain a first line current I₁And a second line current I₂. Integrating the direct-current bus voltage detected under the third voltage pulse V3 in a third preset time t3 and averaging to obtain a second bus voltage Vdc 2; and sampling the current at different moments t3 in a third preset time to obtain a third line current I₃And a fourth line current I₄. Integrating the direct-current bus voltage detected under the fifth voltage pulse V5 in a fifth preset time t5 and averaging to obtain a third bus voltage Vdc 3; and sampling the current at different moments t5 in a fifth preset time to obtain a fifth line current I₅And a sixth line current I₆。

In step S300, a quadrature axis inductance parameter and a direct axis inductance parameter are calculated according to the dc bus voltage under the forward voltage pulse, the first current value, the second current value, and the current collection time interval.

In the present embodiment, the first bus voltage Vdc1, the second bus voltage Vdc2, the third bus voltage Vdc3 and the first line current I are determined according to the first bus voltage Vdc1, the second bus voltage Vdc2 and the first line current I₁A second line current I₂A third line current I₃Fourth line current I₄A fifth line current I₅And a sixth line current I₆And calculating to obtain a quadrature axis inductance parameter Lq of the permanent magnet synchronous motor and a direct axis inductance parameter Ld of the permanent magnet synchronous motor.

Specifically, referring to fig. 6, step S300 includes the following steps.

In step S310, calculating a difference between the first line current and the second line current to obtain a first current difference; calculating the difference value of the third line current and the fourth line current to obtain a second current difference value; and calculating the difference value of the fifth line current and the sixth line current to obtain a third current difference value.

In the present embodiment, according to the first line current I₁And a second line current I₂Obtaining a first current difference

And corresponding first current acquisition time detection Δ t₁(ii) a According to the third line current I₃And a fourth line current I₄Obtaining a second current difference value

And corresponding second current acquisition time detection Δ t₂(ii) a According to the fifth line current I₅And a sixth line current I₆Obtaining a third current difference value

And a corresponding third current acquisition time detection Δ t₃。

In step S320, a line-line inductance L between the first phase and the second phase is calculated according to the first bus voltage, the second bus voltage, the third bus voltage, the first current difference, the second current difference, the third current difference, and the current collection time interval₁₂Line-to-line inductance L between the second and third phases₂₃And a line-to-line inductance L between the third phase and the first phase₃₁。

In the present embodiment, the first bus barVoltage Vdc1, first current difference

And corresponding first current acquisition time detection Δ t₁Calculating to obtain the line-line inductance L between the first phase and the second phase₁₂(ii) a According to the second bus voltage Vdc2 and the second current difference

And corresponding second current acquisition time detection Δ t₂Calculating to obtain the line-line inductance L between the second phase and the third phase₂₃(ii) a And a third current difference according to a third bus voltage Vdc3

And a corresponding third current acquisition time detection Δ t₃Calculating to obtain the line-line inductance L between the third phase and the first phase₃₁。

In the present embodiment, the formula is used

Calculating to obtain the line-line inductance L between the first phase and the second phase₁₂(ii) a In the same way, using the formula

Calculating to obtain the line-line inductance L between the second phase and the third phase₂₃(ii) a Using formulas

Calculating to obtain the line-line inductance L between the third phase and the first phase₃₁。

In step S330, a line-to-line inductance L between the first phase and the second phase is determined₁₂Line-to-line inductance L between the second and third phases₂₃And a line-to-line inductance L between the third phase and the first phase₃₁And calculating the quadrature axis inductance parameter of the permanent magnet synchronous motor by the following formulaL _qAnd direct axis inductance parameter of permanent magnet synchronous motorL _d。

In this embodiment, according to the following formula:

(13)

(14)

(15)

(16)

(17)

(18)

，

(19)

obtaining quadrature axis inductance parameters of the permanent magnet synchronous motorL _qAnd direct axis inductance parameter of permanent magnet synchronous motorL _d。

According to the motor parameter identification method provided by the embodiment of the invention, when the permanent magnet synchronous motor is in a standing state, forward voltage pulses are sequentially applied to any two-phase bridge arm by the permanent magnet synchronous motor, and three line-line inductances between two phases are calculated by detecting the current of the permanent magnet synchronous motor under the action of the forward voltage pulses; and further calculating the direct axis inductance parameter according to a theoretical formulaL _dAnd quadrature axis inductance parameterL _q. Under the condition of unknown motor inductance parameters, the method can identify the inductance parameters very simply and conveniently before the motor runs, does not need external equipment to fix the rotating shaft of the permanent magnet synchronous motor, does not need a rotor stalling experiment, and can realize the direct-axis inductance parametersL _dAnd quadrature axis inductance parameterL _qThe method is simple and convenient, easy to realize and capable of improving the identification precision.

Further, switching on two phase bridge arms according to a first preset mode, switching off a third phase bridge arm, and applying a forward voltage pulse to a winding of the permanent magnet synchronous motor; switching on the two-phase bridge arms according to a second preset mode, switching off the third phase bridge arm, and applying reverse voltage pulse to a winding of the permanent magnet synchronous motor; the first preset mode is that one phase of upper bridge arm is conducted with the other phase of lower bridge arm; the second preset mode is that one phase of lower bridge arm is conducted with the other phase of upper bridge arm; the positive voltage pulse and the reverse voltage pulse have opposite action directions, equal amplitude and equal action time, so that the action force acting on the motor rotor is 0, the inductance parameter identification error caused by rotor displacement is reduced to the maximum extent, and the identification precision is improved.

Fig. 7 is a schematic structural diagram of a motor parameter identification device according to an embodiment of the present invention. As shown in fig. 7, the motor parameter identification device includes a pulse signal generator 210, an inverter 220, a control module 230, and an inductance calculation module 240.

The output of the pulse signal generator 210 is connected to the input of the inverter 220, and the output of the inverter 220 is connected to the input of the permanent magnet synchronous motor 270.

And a pulse signal generator 210 for generating a pulse signal.

And the control module 230 is connected with the pulse signal generator 210 and is used for controlling the pulse signal generator 210 to sequentially generate pulse signals.

The inverter 220 is connected between the pulse generator 210 and the permanent magnet synchronous motor 270, and is configured to turn on any two-phase bridge arm according to the pulse signal in a first preset turn-on manner or a second preset turn-on manner, apply a forward voltage pulse to a winding of the permanent magnet synchronous motor in the first preset turn-on manner, and apply a reverse voltage pulse to the winding of the permanent magnet synchronous motor in the second preset turn-on manner.

In this embodiment, the first phase is an a phase, the second phase is a B phase, and the third phase is a C phase, but the present invention is not limited thereto. Specifically, two-phase bridge arms are conducted according to a first preset mode, and positive voltage pulses are applied to a winding of the permanent magnet synchronous motor; switching on the two-phase bridge arms according to a second preset mode, and applying reverse voltage pulse to a winding of the permanent magnet synchronous motor; the first preset mode is that an upper bridge arm of one phase is conducted with a lower bridge arm of the other phase; the second preset mode is that the lower bridge arm of one phase is communicated with the upper bridge arm of the other phase; the forward voltage pulse and the reverse voltage pulse have opposite action directions and equal amplitudes, and the application time is the same.

The control module 230 is further configured to obtain a dc bus voltage under the forward voltage pulse, and acquire a first current value and a second current value of a corresponding winding on the conducting bridge arm at different times under the forward voltage pulse, where a time interval between the different times is a current acquisition time interval.

In the present embodiment, the control module 230 includes a first control unit 231, a second control unit 232, a third control unit 233, and a first detection unit 234 (see fig. 8), wherein:

the first control unit 231 is configured to control the pulse signal generator 210 to generate the first pulse signal and the second pulse signal. The first pulse signal is used for conducting a first-phase upper bridge arm and a second-phase lower bridge arm in the inverter 220, disconnecting the first-phase lower bridge arm, the second-phase upper bridge arm, a third-phase upper bridge arm and a third-phase lower bridge arm in the inverter 220, and applying a first voltage pulse V1 with the duration of first preset time t1 to a winding of the permanent magnet synchronous motor 250; the second pulse signal is used to turn on a first-phase lower bridge arm and a second-phase upper bridge arm in the inverter 220, turn off the first-phase upper bridge arm, the second-phase lower bridge arm, a third-phase upper bridge arm and a third-phase lower bridge arm in the inverter 220, and apply a second voltage pulse V2 with a duration of a second preset time t2 to a winding of the permanent magnet synchronous motor 250.

The second control unit 232 is configured to control the pulse signal generator 210 to generate the third pulse signal and the fourth pulse signal. The third pulse signal is used for switching on a second-phase upper bridge arm and a third-phase lower bridge arm in the inverter 220, switching off the second-phase lower bridge arm, the third-phase upper bridge arm, the first-phase upper bridge arm and the first-phase lower bridge arm in the inverter 220, and applying a second voltage pulse V3 with the duration of a third preset time t3 to a winding of the permanent magnet synchronous motor 250; the fourth pulse signal is used to turn on the second-phase lower bridge arm and the third-phase upper bridge arm in the inverter 220, turn off the second-phase upper bridge arm, the third-phase lower bridge arm, the first-phase upper bridge arm and the first-phase lower bridge arm in the inverter 220, and apply a fourth voltage pulse V4 with a duration of a fourth preset time t4 to the winding of the permanent magnet synchronous motor 250.

A third control unit 233 for controlling the pulse signal generator 210 to generate the fifth pulse signal and the sixth pulse signal. The fifth pulse signal is used for switching on a third-phase upper bridge arm and a first-phase lower bridge arm in the inverter 220, switching off the third-phase lower bridge arm, the first-phase upper bridge arm, the second-phase upper bridge arm and the second-phase lower bridge arm in the inverter 220, and applying a third voltage pulse V5 with the duration of fifth preset time t5 to a winding of the permanent magnet synchronous motor 250; the sixth pulse signal is used to turn on the third-phase lower bridge arm and the first-phase upper bridge arm in the inverter 220, turn off the third-phase upper bridge arm, the first-phase lower bridge arm, the second-phase upper bridge arm and the second-phase lower bridge arm in the inverter 220, and apply a sixth voltage pulse V6 with a duration of a sixth preset time t6 to the winding of the permanent magnet synchronous motor 250.

The control module 230 is further configured to control the pulse signal generator to generate a forward pulse signal when the current of the three-phase winding of the permanent magnet synchronous motor 270 is zero and the rotor is in a stationary state, and the inverter applies a forward voltage pulse to the winding of the permanent magnet synchronous motor according to the forward pulse signal.

Specifically, when the three-phase winding current of the permanent magnet synchronous motor 270 is zero and the rotor is in a static state, the control module 230 controls the pulse signal generator 210 to generate a forward pulse signal, where the forward pulse signal includes a first pulse signal, a third pulse signal and a fifth pulse signal, and the inverter 220 applies a forward voltage pulse to the winding of the permanent magnet synchronous motor according to the forward pulse signal, where the forward voltage pulse includes a first voltage pulse, a third voltage pulse and a fifth voltage pulse.

Preferably, after the inverter 220 applies the reverse voltage pulse to the winding of the permanent magnet synchronous motor 270, the three-phase winding current of the permanent magnet synchronous motor 270 is set to zero and the rotor is in a static state by standing for a certain time.

The first detection unit 234 is configured to collect the dc bus voltage in the continuous process of the first voltage pulse, the third voltage pulse, and the fifth voltage pulse, so as to obtain a first bus voltage, a second bus voltage, and a third bus voltage; collecting a first line current and a second line current at different moments in the first voltage pulse duration process, collecting a third line current and a fourth line current at different moments in the third voltage pulse duration process, and collecting a fifth line current and a sixth line current at different moments in the fifth voltage pulse duration process; the time interval between the different moments is set time.

In this embodiment, the dc bus voltage and the current under the first voltage pulse, the third voltage pulse and the fifth voltage pulse are respectively sampled, and the first bus voltage Vdc1, the second bus voltage Vdc2, the third bus voltage Vdc3 and the first line current I are calculated₁A second line current I₂A third line current I₃Fourth line current I₄A fifth line current I₅And a sixth line current I₆。

Specifically, the direct-current bus voltage and the direct-current bus current under the first voltage pulse V1 are sampled, and the first bus voltage Vdc1 and the first line current I are calculated₁And a second line current I₂(ii) a Sampling the voltage and current of the DC bus under the third voltage pulse V3, and countingCalculating to obtain a second bus voltage Vdc2 and a third line current I₃And a fourth line current I₄(ii) a Sampling the direct-current bus voltage and current under the fifth voltage pulse V5, and calculating to obtain a third bus voltage Vdc3 and a fifth line current I₅And a sixth line current I₆。

And the inductance calculation module 240 is configured to calculate quadrature axis inductance parameters and direct axis inductance parameters according to the dc bus voltage under the forward voltage pulse, the first current value, the second current value, and the current collection time interval.

Specifically, the first line current I is firstly obtained according to the first bus voltage Vdc1₁And a second line current I₂Calculating to obtain the line-line inductance L between the first phase and the second phase₁₂(ii) a According to the second bus voltage Vdc2 and the third line current I₃And a firstFour-wire current I₄Calculating to obtain the line-line inductance L between the second phase and the third phase₂₃(ii) a And a fifth line current I according to the third bus voltage Vdc3₅And a sixth line current I₆Calculating to obtain the line-line inductance L between the third phase and the first phase₃₁。

In the present embodiment, according to the first line current I₁And a second line current I₂To obtain

And corresponding Δ t₁₂Using the formula

Calculating to obtain the line-line inductance L between the first phase and the second phase₁₂(ii) a In a similar manner, according to the third line current I₃And a fourth line current I₄To obtain

And corresponding Δ t₂₃Using the formula

Calculating to obtain the line-line inductance L between the second phase and the third phase₂₃(ii) a According to the fifth line current I₅And a sixth line current I₆To obtain

And corresponding Δ t₃₁Using the formula

And then according to the line-to-line inductance L between the first and second phases₁₂Line-to-line inductance L between the second and third phases₂₃And a line-to-line inductance L between the third phase and the first phase₃₁Calculating to obtain quadrature axis inductance parameters of the permanent magnet synchronous motorL _qAnd direct axis inductance parameter of permanent magnet synchronous motorL _d。

In the present embodiment, the following formula is used

(20)

(21)

(22)

(23)

(24)

(25)

(26)

(27)

The motor parameter identification device provided by the embodiment of the invention,

the method comprises the steps of sequentially applying forward voltage pulses to any two-phase bridge arm to the permanent magnet synchronous motor when the permanent magnet synchronous motor is in a standing state, and calculating three two-phase bridge arms by detecting the current of the permanent magnet synchronous motor under the action of the forward voltage pulsesLine-to-line inductance between; and further calculating the direct axis inductance parameter according to a theoretical formulaL _dAnd quadrature axis inductance parameterL _q. Under the condition of unknown motor inductance parameters, the method can identify the inductance parameters very simply and conveniently before the motor runs, does not need external equipment to fix the rotating shaft of the permanent magnet synchronous motor, does not need a rotor stalling experiment, and can realize the direct-axis inductance parametersL _dAnd quadrature axis inductance parameterL _qThe method is simple and convenient, easy to realize and capable of improving the identification precision.

While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A motor parameter identification method is characterized by comprising the following steps:

sequentially controlling the inverter to conduct any two phase bridge arms according to a first preset conduction mode and a second preset conduction mode, disconnecting a third phase bridge arm, applying forward voltage pulses to a winding of the permanent magnet synchronous motor in the first preset conduction mode, and applying reverse voltage pulses to the winding of the permanent magnet synchronous motor in the second preset conduction mode;

acquiring direct-current bus voltage under a forward voltage pulse, and acquiring a first current value and a second current value of a corresponding winding on a conducting bridge arm at different moments under the forward voltage pulse, wherein a time interval between the different moments is a current acquisition time interval;

calculating quadrature axis inductance parameters and direct axis inductance parameters according to the direct current bus voltage under the forward voltage pulse, the first current value, the second current value and the current acquisition time interval;

the first preset conduction mode is that an upper bridge arm of a first phase of the two phases is conducted with a lower bridge arm of a second phase of the two phases; the second preset conduction mode is that the lower bridge arm of the first phase of the two phases is conducted with the upper bridge arm of the second phase of the two phases; the action directions of the forward voltage pulse and the reverse voltage pulse are opposite.

2. The motor parameter identification method according to claim 1, wherein sequentially controlling the inverter to conduct any two phase bridge arms according to a first preset conduction mode and a second preset conduction mode, and disconnecting a third phase bridge arm, wherein in the first preset conduction mode, applying a forward voltage pulse to the winding of the permanent magnet synchronous motor, and in the second preset conduction mode, applying a reverse voltage pulse to the winding of the permanent magnet synchronous motor comprises:

switching on a first-phase upper bridge arm and a second-phase lower bridge arm in the inverter, switching off the first-phase lower bridge arm, the second-phase upper bridge arm, a third-phase upper bridge arm and a third-phase lower bridge arm in the inverter, and applying a first voltage pulse with the duration of first preset time to a winding of the permanent magnet synchronous motor;

switching on a first-phase lower bridge arm and a second-phase upper bridge arm in the inverter, switching off the first-phase upper bridge arm, the second-phase lower bridge arm, a third-phase upper bridge arm and a third-phase lower bridge arm in the inverter, and applying a second voltage pulse with the duration of a second preset time to a winding of the permanent magnet synchronous motor;

switching on a second-phase upper bridge arm and a third-phase lower bridge arm in the inverter, switching off the second-phase lower bridge arm, the third-phase upper bridge arm, the first-phase upper bridge arm and the first-phase lower bridge arm in the inverter, and applying a third voltage pulse with the duration of third preset time to a winding of the permanent magnet synchronous motor;

switching on a second-phase lower bridge arm and a third-phase upper bridge arm in the inverter, switching off the second-phase upper bridge arm, the third-phase lower bridge arm, the first-phase upper bridge arm and the first-phase lower bridge arm in the inverter, and applying a fourth voltage pulse with the duration of fourth preset time to a winding of the permanent magnet synchronous motor;

switching on a third-phase upper bridge arm and a first-phase lower bridge arm in the inverter, switching off the third-phase lower bridge arm, the first-phase upper bridge arm, the second-phase upper bridge arm and the second-phase lower bridge arm in the inverter, and applying a fifth voltage pulse with the duration of fifth preset time to a winding of the permanent magnet synchronous motor;

and switching on a third-phase lower bridge arm and a first-phase upper bridge arm in the inverter, switching off the third-phase upper bridge arm, the first-phase lower bridge arm, the second-phase upper bridge arm and the second-phase lower bridge arm in the inverter, and applying a sixth voltage pulse with the duration of sixth preset time to a winding of the permanent magnet synchronous motor.

3. The method of claim 2, wherein the positive voltage pulse is applied to the winding of the PMSM when the three-phase winding current of the PMSM is zero and the rotor is at rest.

4. The method for identifying motor parameters of claim 3, wherein after the reverse voltage pulse is applied to the winding of the permanent magnet synchronous motor, the permanent magnet synchronous motor is allowed to stand for a certain time to make the three-phase winding current of the permanent magnet synchronous motor zero and make the rotor in a static state.

5. The motor parameter identification method of claim 3, wherein obtaining the DC bus voltage under the forward voltage pulse, and acquiring the first current value and the second current value of the corresponding winding on the conducting bridge arm at different times under the forward voltage pulse comprises:

collecting direct-current bus voltage in the continuous process of the first voltage pulse, the third voltage pulse and the fifth voltage pulse to obtain first bus voltage, second bus voltage and third bus voltage; collecting a first line current and a second line current at different moments in the first voltage pulse duration, collecting a third line current and a fourth line current at different moments in the third voltage pulse duration, and collecting a fifth line current and a sixth line current at different moments in the fifth voltage pulse duration; the time interval between the different moments is set time.

6. The motor parameter identification method according to claim 5, wherein calculating the quadrature axis inductance parameter and the direct axis inductance parameter according to the dc bus voltage under the forward voltage pulse, the first current value, the second current value, and the current collection time interval comprises:

calculating the difference value of the first line current and the second line current to obtain a first current difference value; calculating a difference value between the third line current and the fourth line current to obtain a second current difference value; calculating a difference value between the fifth line current and the sixth line current to obtain a third current difference value; calculating to obtain a line-line inductance L between a first phase and a second phase of the permanent magnet synchronous motor according to a formula U = L₁₂Line-to-line inductance L between the second and third phases₂₃And a line-to-line inductance L between the third phase and the first phase₃₁；

According to

，

，

，

，

，

，

，

，

Calculating to obtain quadrature axis inductance parameters of the permanent magnet synchronous motor

And direct axis inductance parameter

。

7. An identification method according to claim 3, wherein the first voltage pulse and the second voltage pulse act in opposite directions; the third voltage pulse and the fourth voltage pulse have opposite action directions, and the fifth voltage pulse and the sixth voltage pulse have opposite action directions.

8. The identification method according to claim 3, wherein the first predetermined time is equal to the second predetermined time; the third preset time is equal to the fourth preset time; the fifth preset time is equal to the sixth preset time.

9. The identification method according to claim 5, further comprising:

integrating and averaging the direct-current bus voltage detected under the first voltage pulse within the first preset time to obtain the first bus voltage, and sampling currents at different moments within the first preset time to obtain the first line current and the second line current;

integrating and averaging the direct-current bus voltage detected under the third voltage pulse within the third preset time to obtain the second bus voltage, and sampling currents at different moments within the third preset time to obtain the third line current and the fourth line current;

and integrating and averaging the direct-current bus voltage detected under the fifth voltage pulse within the fifth preset time to obtain the third bus voltage, and sampling currents at different moments within the fifth preset time to obtain the fifth line current and the sixth line current.

10. An electric machine parameter identification device, comprising:

a pulse signal generator for generating a pulse signal;

the control module is connected with the pulse signal generator and is used for controlling the pulse signal generator to sequentially generate pulse signals;

the inverter is connected between the pulse generator and the permanent magnet synchronous motor and is used for conducting any two-phase bridge arm according to the pulse signal in a first preset conducting mode or a second preset conducting mode, disconnecting the third-phase bridge arm, applying a forward voltage pulse to a winding of the permanent magnet synchronous motor in the first preset conducting mode and applying a reverse voltage pulse to the winding of the permanent magnet synchronous motor in the second preset conducting mode;

the control module is further used for acquiring direct-current bus voltage under the forward voltage pulse, and acquiring a first current value and a second current value of a corresponding winding on a conducting bridge arm at different moments under the forward voltage pulse, wherein a time interval between the different moments is a current acquisition time interval;

the inductance calculation module is used for calculating quadrature axis inductance parameters and direct axis inductance parameters according to the direct current bus voltage under the forward voltage pulse, the first current value, the second current value and the current acquisition time interval;

11. The motor parameter identification device of claim 10, wherein the control module comprises:

the first control unit is used for controlling the pulse signal generator to generate a first pulse signal and a second pulse signal;

the second control unit is used for controlling the pulse signal generator to generate a third pulse signal and a fourth pulse signal;

the third control unit is used for controlling the pulse signal generator to generate a fifth pulse signal and a sixth pulse signal;

the first pulse signal is used for conducting a first-phase upper bridge arm and a second-phase lower bridge arm in the inverter, disconnecting the first-phase lower bridge arm, the second-phase upper bridge arm, a third-phase upper bridge arm and a third-phase lower bridge arm in the inverter, and applying a first voltage pulse with the duration of first preset time to a winding of the permanent magnet synchronous motor;

the second pulse signal is used for conducting a first-phase lower bridge arm and a second-phase upper bridge arm in the inverter, disconnecting the first-phase upper bridge arm, the second-phase lower bridge arm, a third-phase upper bridge arm and a third-phase lower bridge arm in the inverter, and applying a second voltage pulse with the duration of a second preset time to a winding of the permanent magnet synchronous motor;

the third pulse signal is used for conducting a second-phase upper bridge arm and a third-phase lower bridge arm in the inverter, disconnecting the second-phase lower bridge arm, the third-phase upper bridge arm, the first-phase upper bridge arm and the first-phase lower bridge arm in the inverter, and applying a third voltage pulse with the duration of a third preset time to a winding of the permanent magnet synchronous motor;

the fourth pulse signal switches on a second-phase lower bridge arm and a third-phase upper bridge arm in the inverter, switches off the second-phase upper bridge arm, the third-phase lower bridge arm, the first-phase upper bridge arm and the first-phase lower bridge arm in the inverter, and applies a fourth voltage pulse with the duration of fourth preset time to a winding of the permanent magnet synchronous motor;

the fifth pulse signal is used for conducting a third phase upper bridge arm and a first phase lower bridge arm in the inverter, disconnecting the third phase lower bridge arm, the first phase upper bridge arm, the second phase upper bridge arm and the second phase lower bridge arm in the inverter, and applying a fifth voltage pulse with the duration of fifth preset time to a winding of the permanent magnet synchronous motor;

and the sixth pulse signal is used for conducting a third-phase lower bridge arm and a first-phase upper bridge arm in the inverter, disconnecting the third-phase upper bridge arm, the first-phase lower bridge arm, the second-phase upper bridge arm and the second-phase lower bridge arm in the inverter, and applying a sixth voltage pulse with the duration of sixth preset time to a winding of the permanent magnet synchronous motor.

12. The apparatus of claim 11, wherein the control module is further configured to control the pulse signal generator to generate a forward pulse signal when the three-phase winding current of the pmsm is zero and the rotor is in a stationary state, and the inverter applies a forward voltage pulse to the winding of the pmsm according to the forward pulse signal.

13. The apparatus of claim 11, wherein the inverter applies a reverse voltage pulse to the winding of the PMSM, and then the PMSM is allowed to stand for a certain time to make the three-phase winding current of the PMSM zero and the rotor in a static state.

14. The motor parameter identification device of claim 11, wherein the control module further comprises:

the first detection unit is used for acquiring the direct-current bus voltage in the continuous process of the first voltage pulse, the third voltage pulse and the fifth voltage pulse to obtain a first bus voltage, a second bus voltage and a third bus voltage; collecting a first line current and a second line current at different moments in the first voltage pulse duration process, collecting a third line current and a fourth line current at different moments in the third voltage pulse duration process, and collecting a fifth line current and a sixth line current at different moments in the fifth voltage pulse duration process; the time interval between the different moments is set time.

15. The apparatus of claim 14, wherein the inductance calculation module is further configured to calculate a difference between the first line current and the second line current to obtain a first current difference; calculating the difference value of the third line current and the fourth line current to obtain a second current difference value; calculating a difference value between the fifth line current and the sixth line current to obtain a third current difference value;

the inductance calculation module is further used for calculating a line-line inductance L between a first phase and a second phase of the permanent magnet synchronous motor according to a formula U = L.DELTA.i/DELTA.t, a first bus voltage, a second bus voltage, a third bus voltage, a first current difference, a second current difference, a third current difference and a current acquisition time interval₁₂Line-to-line inductance L between the second and third phases₂₃And a line-to-line inductance L between the third phase and the first phase₃₁；

The inductance calculation module is also used for calculating the inductance according to a formula

，

，

，

，

，

，

，

，

16. The motor parameter identification device of claim 11, wherein the first voltage pulse and the second voltage pulse act in opposite directions; the third voltage pulse and the fourth voltage pulse have opposite action directions, and the fifth voltage pulse and the sixth voltage pulse have opposite action directions.

17. The apparatus of claim 11, wherein the first predetermined time is equal to the second predetermined time; the third preset time is equal to the fourth preset time; the fifth preset time is equal to the sixth preset time.

18. The device for identifying motor parameters of claim 15, wherein the first detecting unit is further configured to integrate and average the dc bus voltage detected under the first voltage pulse within a first preset time to obtain a first bus voltage, and sample the current at different times within the first preset time to obtain a first line current and a second line current;

the first detection unit is further configured to integrate and average the dc bus voltage detected under the third voltage pulse within a third preset time to obtain a second bus voltage, and sample currents at different times within the third preset time to obtain a third line current and a fourth line current;

the first detection unit is further configured to integrate the dc bus voltage detected under the fifth voltage pulse within a fifth preset time, average the integrated dc bus voltage to obtain a third bus voltage, and sample currents at different times within the fifth preset time to obtain a fifth line current and a sixth line current.