TWI616666B - Initial N/S pole accurate identification method for permanent magnet auxiliary synchronous reluctance motor rotor - Google Patents

Abstract

The invention discloses an initial N/S pole accurate identification method for a permanent magnet auxiliary synchronous reluctance motor rotor. The identification method is directed to a permanent magnet auxiliary synchronous reluctance motor rotor having two or more magnetic barriers, two or two layers The magnetic steel is embedded in the magnetic barriers adjacent to each other, and the positions of the magnetic barriers of the magnetic layers are relatively uniform. For the permanent magnet auxiliary synchronous reluctance motor rotor having the above characteristics, the identification method detects the response d, q current increase by applying a voltage vector uniformly distributed in the one-electrode period and having the same amplitude for the same preset time. The amount of size, and then the special characteristics of the permanent magnet assisted synchronous reluctance motor increase / demagnetization circuit to distinguish the polarity of the magnetic pole, thus determining the initial position of the rotor. The invention solves the problem that the existing magnetic pole detecting technology recognizes the initial N/S pole position error of the permanent magnet auxiliary synchronous reluctance motor rotor, and further eliminates the obstacle that the permanent magnet auxiliary synchronous reluctance motor is put into the market.

Description

Initial N/S pole accurate identification method for rotor of permanent magnet auxiliary synchronous reluctance motor

The invention relates to a synchronous motor detecting technology field, and particularly relates to a method for accurately identifying an initial N/S pole of a permanent magnet auxiliary synchronous reluctance motor rotor.

Synchronous reluctance motors rely entirely on the difference in magnetoresistance of the d and q axis magnetic circuits to generate torque. Since there are no guide bars on the rotor, there is no electromagnetic loss, which is higher efficiency and lower stable operating temperature than induction motors. By optimizing the reluctance torque of the synchronous magnetic reluctance motor rotor magnetic barrier, the torque density of the induction motor can be achieved. At present, the problem of limiting the widespread application of synchronous reluctance motors is mainly due to the low power factor, which needs to be driven with a large-capacity inverter. The permanent magnet auxiliary synchronous reluctance motor can effectively increase the power factor by adding magnetic steel in the magnetic barrier of the original synchronous reluctance motor rotor. At the same time, part of the permanent magnet torque accompanying the magnetic steel will further increase. Synchronous reluctance motor torque density. Therefore, the multi-faceted advantages of the permanent magnet-assisted synchronous reluctance motor make it have an extremely broad market prospect.

The drive system of the permanent magnet auxiliary synchronous reluctance motor is exactly the same as the permanent magnet synchronous motor, and the control method is also the same. In the permanent magnet synchronous motor drive system, the detection and initial positioning of the rotor position of the motor is the basic condition for the system operation, and it is also a necessary prerequisite for vector control. To this end, the prior art provides an initial N/S pole identification method for a permanent magnet synchronous motor rotor. By applying voltage vectors of different spatial angles and equal amplitudes to the motor windings, the voltage vector corresponding to the voltage vector is respectively detected. The closer the voltage space vector is to the N pole of the rotor, the larger the response current vector increment in the magnetization direction due to the saturation characteristics of the stator core. Therefore, the rotor N/S pole information can be obtained by detecting the current response increment value. Existing patent The technology provides a permanent N-S pole identification method for a permanent magnet synchronous motor rotor. In order to obtain a more accurate rotor position, further innovations and improvements are made for the above method, but the basic principle is consistent.

However, the rotor initial N/S pole identification method of the above permanent magnet synchronous motor is not suitable for the permanent magnet auxiliary synchronous reluctance motor. Different from the permanent magnet synchronous motor with permanent magnet magnetic field as the main magnetic field, the permanent magnet magnetic field in the permanent magnet auxiliary synchronous reluctance motor only plays an auxiliary role, and the main excitation magnetic field is the d-axis component of the armature winding magnetic field. When the rotor N/S pole (ie ±d axis) is identified, the demagnetization direction voltage vector will change the original magnetic field path, resulting in the demagnetization direction current response increment value greater than the magnetization direction current response increment value, resulting in the actual N The position of the pole is identified as a misunderstanding of the S pole.

For the permanent magnet auxiliary synchronous reluctance motor, even if the N/S pole position is reversed, the motor can start and work normally, but the magnetic steel will completely react at this time, and the current will increase during the customer's use. Low power factor, poor speed or poor overload capability may eventually lead to downtime, which is often difficult for non-professional users to detect.

In summary, it is necessary to propose a special rotor initial N/S pole accurate identification method for permanent magnet auxiliary synchronous reluctance motor.

Aiming at the problem that the existing magnetic pole detection technology cannot accurately identify the initial N/S pole position of the rotor of the permanent magnet auxiliary synchronous reluctance motor, the object of the present invention is to provide an initial N/S pole accurate identification method for the permanent magnet auxiliary synchronous reluctance motor rotor.

In order to achieve the above object, the present invention adopts the following technical solution: an initial N/S pole accurate identification method for a permanent magnet auxiliary synchronous reluctance motor rotor, the identification method is applied to the stator windings by uniformly distributing the amplitudes uniformly in one electrical cycle, Continue the same pre- Set the voltage vector of time, detect the magnitude of the d and q current increments, and then use the special characteristics of the permanent magnet auxiliary synchronous reluctance motor to remove the magnetic circuit to distinguish the polarity of the magnetic pole to determine the initial position of the rotor.

Further, the identification method firstly divides an electric cycle k of the permanent magnet auxiliary synchronous reluctance motor into equal parts, k must be greater than or equal to 8; assuming that the -d axis is on the bisector, assuming that the -q axis is ahead of the -d axis 90 °At the position of the electrical angle; simultaneously apply voltage vectors of equal amplitude for the same preset time to each aliquot, sample at least two phase winding currents, perform a park conversion to obtain the assumed time on the d-axis The current response increment, the larger the current increment value, the closer the -d axis is to the real S pole, for initial identification of the initial N/S pole of the rotor; then, the precise subdivision is performed, and the windings are equally applied with the same amplitude and duration. For the voltage vector of the same preset time, repeat the above process, calculate the current increment of the assumed -d axis preset time and the current increment of the assumed -q axis preset time. The greater the difference between the two, the corresponding - The closer the d-axis is to the real S-pole, the better the initial N/S pole of the rotor.

Further, the identification method specifically includes the following steps: Step 1: equally divide an electrical period k of the permanent magnet auxiliary synchronous reluctance motor, k must be greater than or equal to 8, Δ θ ₀ = 360 ° / k . Assume that the -d axis is on the bisector, assuming that the -q axis is at a position that is assumed to be at an electrical angle of -10° from the -d axis; simultaneously applying voltage vectors of equal magnitude for the same preset time to each aliquot, sampling at least two Phase winding current, park conversion is obtained by assuming the current increment Δ i _{d in the} preset time on the -d axis, and the assumed -d-axis current response increment Δ i _{d is} obtained corresponding to each voltage vector, and the maximum current increment is extracted. The voltage vector position θ ₁ corresponding to i _d is the true-d-axis (S-pole) coarse position; Step 2: The true-d-axis (S-pole) coarse position θ _{1 is} obtained from step ₁ , and the deviation from the θ ₁ position is ±Δ θ The two positions of the ₀ /2 electrical angle are respectively applied with the voltage vector of step 1, assuming that the -d axis is at this position, assuming that the -q axis is at a position that is assumed to be -10° electrical angle of the -d axis. Sampling at least two phase winding currents, performing park conversion to obtain a current increment Δ i _{d 1} within a predetermined time period of the _d- axis and a current increment Δ i _{q 1} within a predetermined time period of the -q axis, comparing Δ i _{d 1} -△ i _{q 1} , extracting the voltage vector position θ ₂ of the larger value of Δ i _{d 1} -Δ i _{q 1} is the true -d axis (S pole) closer to the position; Step 3: repeating step 2 until more accurate From the true-d-axis (S-pole) position θ _r , the true initial d-axis (N-pole) position θ _{f of the} rotor is obtained for an electrical angle of θ _r ±180°.

Further, the permanent magnet auxiliary synchronous reluctance motor rotor has two or more magnetic barriers, and two or more layers of magnetic barriers are sequentially embedded in the magnetic barrier, and the magnetic barriers are respectively located in the magnetic barriers. Consistent.

The method of the invention solves the misunderstanding that the existing magnetic pole detection technology is applied to the permanent magnet auxiliary synchronous reluctance motor, and the N/S pole detection reverse occurs. At the same time, the method of the invention also reflects from the side that the control of the permanent magnet auxiliary synchronous reluctance motor needs to be used with a frequency converter having a special software body, and the conventional permanent magnet synchronous motor frequency converter will inevitably generate some unnecessary troubles.

In addition, this initial N/S pole identification method has been tested many times, and the error can be controlled within a very small range, which provides a guarantee for the efficient and normal operation of the permanent magnet auxiliary synchronous reluctance motor, and further eliminates the permanent magnet auxiliary synchronous magnetic Obstacles to the market for resistance motors.

1‧‧‧Magnetic steel

2‧‧‧Magnetic barrier

3‧‧‧Edge magnetic bridge area

ω ‧‧‧ electrical angular velocity

p ‧‧‧Motor pole pairs

R1‧‧‧ stator phase resistance

ψ _pm ‧‧‧ magnet rotor flux generated in the stator winding

u _d ‧‧‧The component of the stator current space vector in the d-axis direction

u _q ‧‧‧The component of the stator current space vector in the q-axis direction

i _d ‧‧‧The component of the stator current space vector in the d-axis direction

i _q ‧‧‧The component of the stator current space vector in the q-axis direction

L _d ‧‧‧d shaft inductance

L _q ‧‧‧q axis inductance

1 is a flow chart of the identification step of the present invention.

2 is a schematic view showing the structure of a rotor of a permanent magnet auxiliary synchronous reluctance motor of the present invention.

Fig. 3 is a comparison diagram of the magnetic field distribution of the conventional permanent magnet synchronous motor with no-load magnetic field distribution and equal amplitude applied at the N/S pole position, and the same preset time voltage vector; the left picture is empty, the middle picture N pole, the right picture S pole.

4 is a comparison diagram of the magnetic field distribution after the no-load magnetic field distribution of the permanent magnet auxiliary synchronous reluctance motor of the present invention and the equal amplitude value applied at the N/S pole position, and the voltage vector of the same preset time is continued; Extreme, right S pole.

Figure 5 is a phasor diagram of a permanent magnet assisted synchronous reluctance motor.

In order to make the technical means, creative features, achievement goals and effects achieved by the present invention easy to understand, the present invention will be further described below in conjunction with specific illustrations.

Referring to Fig. 2, there is shown a schematic structural view of a rotor of a permanent magnet auxiliary synchronous reluctance motor according to the present invention, which shows three rotor structures of a permanent magnet auxiliary synchronous reluctance motor.

As can be seen from the figure, the permanent magnet auxiliary synchronous reluctance motor rotor of the present invention has the following features: two or more magnetic barriers 2; two or more layers of magnetic barriers 2 adjacent to each other are embedded with magnetic steel 1 The positions in the magnetic barrier 2 of each layer of the magnetic steel 1 are relatively uniform.

Furthermore, the permanent magnet-assisted synchronous magnetoresistive magnetic steel material is not limited, and both ferrite and rare earth permanent magnet materials are acceptable.

The dimensions of the rotor are not optimized here, and the superiority of the respective structures is not considered. It is only used for illustration. The permanent magnet auxiliary synchronous reluctance motor rotor that satisfies the above characteristic structure is the identification object targeted by the present invention. .

Referring to FIG. 3, the conventional permanent magnet synchronous motor has a no-load magnetic field distribution and an equal amplitude is applied at the N/S pole position, and the magnetic field distribution is continued after the same preset time voltage vector. The left picture shows the no-load magnetic field, and the middle figure N pole is In the state of magnetization, the S pole at the right is demagnetized, and the direction of the applied voltage vector is assumed to be the d-axis. Obviously, the magnetic circuit after applying the voltage vector (whether magnetically added or demagnetized) does not change much compared to the no-load magnetic circuit, except that the magnetic field strength at the core and the air gap changes. Due to the nonlinear magnetization characteristics of the stator core, the d-axis inductance of the magnetization state will be smaller than the d-axis inductance of the demagnetization state. According to the following formula:

It can be seen that due to the application of the voltage vector and the like, the ψ _{d is the} same in both states, and since the d-axis inductance in the magnetization state is smaller than the d-axis inductance in the demagnetization state, the magnetization state Δ i _d > demagnetization can be obtained. State Δ i _d .

Based on the above principle, one electrical cycle k of the permanent magnet synchronous motor is equally divided. Assuming that the d-axis is on the bisector, it is assumed that the q-axis is at a position that is advanced by assuming an electrical angle of 90° from the d-axis. By calculating the maximum current increment Δ i _d , the rough position of the true d-axis (N-pole) is the voltage vector position corresponding to the maximum current increment Δ i _d . The above is the N/S pole identification method of the rotor of the conventional permanent magnet synchronous motor.

Referring to FIG. 4, the magnetic field distribution of the permanent magnet auxiliary synchronous reluctance motor of the present invention and the equal amplitude are applied at the N/S pole position respectively, and the magnetic field distribution is compared after the same preset time voltage vector, and the left picture is the no-load magnetic field. The N pole of the figure is the magnetization state, and the S pole of the right diagram is the demagnetization state, assuming that the direction of the applied voltage vector is also assumed to be the d-axis. Different from the traditional permanent magnet synchronous motor, the demagnetization circuit of the permanent magnet auxiliary synchronous reluctance motor changes greatly compared with the magnetization circuit. The change of the magnetic circuit makes the identification of the rotor N/S not based on the nonlinear magnetization characteristics of the stator core. Judge. In the demagnetization state, the original permanent magnet magnetic field is squeezed by the stator voltage vector magnetic field, and the new magnetic circuit is generated by a part of the narrow magnetic bridge region passing through the rotor and perpendicular to the q-axis region in the figure, and the height of the edge magnetic bridge region is saturated. And the low magnetic permeability caused by the multi-magnetic barrier structure perpendicular to the q-axis region, together with the demagnetization state d-axis inductance will be much smaller than the d-axis inductance in the magnetization state. Through a large number of patterning comparison tests, the above phenomenon occurs for a permanent magnet auxiliary synchronous reluctance motor having the characteristics of claim 1. At this time, according to the formula (1), the magnetization state Δ i _d < the demagnetization state Δ i _d .

Referring to Figure 1, based on the above principles, the present invention is a first auxiliary periodic permanent magnetic synchronous reluctance electrical machine aliquots k, k must be greater than _{8, △ θ 0 = 360 °} / k. Assuming that the -d axis is on the bisector, assume that the -q axis is at a position that is assumed to be an electrical angle of 90° from the -d axis. Applying voltage vectors of equal amplitude and duration for the same preset time on each bisector, sampling at least two phase winding currents, performing park conversion to obtain a current increment Δ i _d within a preset time on the assumed d-axis, corresponding to each voltage vector The obtained assumed d-axis current responds to the increment Δ i _d , and the voltage vector position θ ₁ corresponding to the maximum current increment Δ i _d is extracted as the initial-d-axis (S-pole) coarse position.

Since the coarse positioning θ _{1 of the} true-d axis (S pole) will only exist at the bisector positions of 360°/ k , 2*360°/ k , 3*360°/ k ...360° electrical angle after the actual rotor pole is S may be present at any position, so that in order to achieve a more accurate measurement of the initial position of the permanent magnet assisted synchronous reluctance motor rotor, the present invention is obtained in step coarse position θ _1, θ ₁ to a position near the accurate Subdividing, applying voltage vectors of equal amplitude for the same preset time to two positions θ ₁ + Δ θ ₀ /2 and θ ₁ - Δ θ ₀ /2 respectively, assuming that the -d axis is at the position, then assume - The q-axis is assumed to be at the position of the 90-degree electrical angle of the -d-axis. Sampling at least two phase winding currents, performing park conversion to obtain a current increment Δ i _{d 1} within a predetermined time period of the _d- axis and a current increment Δ i _{q 1} within a predetermined time period of the -q axis, comparing Δ i _{d 1} -△ i _{q 1} , the voltage vector position θ ₂ obtained by extracting a larger value of Δ i _{d 1} -Δ i _{q 1} is closer to the position of the true -d axis (S pole). The specific process is as follows (see Fig. 1): For the two positions θ ₁ + Δ θ ₀ /2 and θ ₁ - Δ θ ₀ /2, the park conversion is performed to obtain the current increment Δ i _d within the preset time of the -d axis. ₁ , Δ i _{d 1} ' and the assumed -q axis current increment Δ i _{q 1} , Δ i _{q 1} '; comparison Δ i _{d 1} - Δ i _{q 1} and Δ i _{d 1} '- Δ i _{q 1} ', the voltage vector position θ ₂ extracted to obtain a larger value is true - the d-axis (S-pole) is closer to the position: if Δ i _{d 1} - Δ i _{q 1} > Δ i _{d 1} '- Δ i _{q 1} ', Then θ ₂ = θ ₁ + Δ θ ₀ /2; if Δ i _{d 1} - Δ i _{q 1} < Δ i _{d 1} '- Δ i _{q 1} ', θ ₂ = θ ₁ - Δ θ ₀ /2.

Further, updating Δ θ ₀ , assigning Δ θ ₀ /2 to the new value Δ θ ₀ , and repeating the above precise subdivision step until the last time Δ θ ₀ < initial setting Δ θ _min . At this time, the true-d-axis (S-pole) precise position θ _r is obtained, and the true initial d-axis (N-pole) position θ _{f of the} rotor is obtained for the electrical angle of θ _r ±180°.

In the step of precise subdivision, it is necessary to simultaneously calculate the assumed -d current increment Δ i _{d 1} and the assumed -q axis current increment Δ i _{q 1} , because in the process of assuming that the -d axis is constantly approaching the true-d axis, despite △ As _{d d 1 is} getting larger and larger, △ i _{q 1 is} getting smaller and smaller, but the variation range between the assumed -d-axis current increments Δ i _{d 1} is getting smaller and smaller, and the rotor cannot be guaranteed simply by extracting the maximum Δ i _{d 1} High precision for position recognition. At this time, it is assumed that the -q-axis current increment Δ i _{q 1} has a higher resolution with respect to the assumed -d-axis current increment Δ i _{d 1} . To get the position closest to the true-d axis, we want to identify the assumed -d-axis position that has both a larger Δ i _{d 1} and a smaller Δ i _{q 1} . Therefore, by comparing Δ i _{d 1} - Δ i _{q 1} , extracting the voltage vector position θ ₂ corresponding to the maximum Δ i _{d 1} - Δ i _{q 1} will have a very high precision.

The basic idea and main features of the present invention have been shown and described above. It should be noted that, unlike the permanent magnet synchronous motor, the permanent magnet auxiliary synchronous reluctance motor can start normally and operate normally even if the rotor N/S pole position is incorrectly identified, specifically by the following output torque formula and FIG. The magnetic Assisted Synchronous Reluctance Motor phasor diagram is explained: T = p ψ _pm i _q + p ( L _d - L _q ) i _d i _q (2)

The first term in the formula is permanent magnet torque and the second term is reluctance torque. p is the pole pair of the motor, L _d and L _q are the d-axis and q-axis inductance respectively, i _d and i _q are the components of the stator current space vector in the d and q directions, respectively, ψ _pm is the rotor magnet in the stator winding A magnetic flux is generated, and the d-axis is generally defined as the N-pole magnetic field direction of the rotor magnet, and the q-axis is rotated 90° counterclockwise in the d-axis direction. Traditional permanent magnet synchronous motors, whether surface-mounted or in-line, the main contribution of output torque is permanent magnet torque. For the permanent magnet auxiliary synchronous reluctance motor, the main contribution component of the output torque is the reluctance torque, and the permanent magnet torque usually accounts for less than 30%. This multi-layer magnetic circuit by a magnetic barrier particularity of the decision result in the rotor, the magnetic field generated by the magnet to form barrier layers subject to [Psi] and ψ _pm stator winding linkage, magnetic energy, whether embedded magnet strength, to bring _Pm will be very limited.

When the N/S pole position identification of the permanent magnet assisted synchronous reluctance rotor is incorrect, the N/S pole position identification in the most extreme case is reversed as an example. Assuming normal state, the output torque is 100Nm = reluctance torque 80Nm + permanent magnet torque 20Nm; when the N/S pole is opposite, it will become reluctance torque 80Nm - permanent magnet torque 20Nm = output torque 60Nm, obviously Because the permanent magnet torque component is small, the motor can still rely on the reluctance torque for starting and normal operation. However, in order to obtain the same 100Nm output torque as the normal state, the motor current is bound to increase greatly, and the motor efficiency is reduced. The increase in heat generation, long-term operation in this state will greatly reduce the life of the motor. Meanwhile, referring to FIG. 5, the phasor diagram of the permanent magnet auxiliary synchronous reluctance motor of the present invention is not embedded in the magnetic steel, and the power factor angle is θ ₁ ; the magnetic steel is embedded, the N/S pole position is correctly identified, and the power factor angle is θ ₂ ; For magnetic steel, the N/S pole position is reversed, and the power factor angle is θ ₃ ; at this time θ ₂ < θ ₁ < θ ₃ , that is, cos θ ₂ >cos θ ₁ >cos θ ₃ . The example shows that the measured power factor of the un-embedded magnetic steel is 0.73, and the embedded magnetic steel adopts the rotor N/S pole identification method of the present invention. The rated power factor is 0.85, and the embedded magnetic steel adopts the conventional permanent magnet synchronous motor identification method. The factor is 0.62.

The above description highlights the importance and necessity of the present invention, further eliminates the obstacles that the permanent magnet auxiliary synchronous reluctance motor is put into the market, and avoids the increase of current which occurs due to the error of the initial position identification of the rotor during the use of the customer. Non-professional users, such as low factors, poor speed or poor overload capacity, are often difficult to detect.

The basic principles, main features, and advantages of the present invention are shown and described above. It is to be understood by those skilled in the art that the present invention is not limited by the foregoing embodiments. The invention is also subject to various modifications and improvements which fall within the scope of the invention as claimed. The scope of the invention is defined by the scope of the appended claims and their equivalents.

Claims (3)

An initial N/S pole accurate identification method for a permanent magnet auxiliary synchronous reluctance motor rotor, wherein the identification method is applied to at least two phase stator windings by uniformly distributing the amplitudes in one electrical cycle to be equal for the same preset time a voltage vector, detecting the response d, q a current response increment size, and then using the permanent magnet auxiliary synchronous reluctance motor to increase the current increment of the magnetostatic state is smaller than the demagnetization state of the current increment to distinguish the permanent magnet assist The polarity of the rotor pole of the synchronous reluctance motor is determined to determine an initial N/S pole of the rotor; wherein the permanent magnet auxiliary synchronous reluctance motor rotor has two or more layers of magnetic barriers, and two or more layers are sequentially adjacent A magnetic steel is embedded in the magnetic barrier, and the positions of the magnetic barrier in the layers of the magnetic steel are relatively uniform. An initial N/S pole accurate identification method for a permanent magnet auxiliary synchronous reluctance motor rotor according to claim 1, wherein the identification method firstly divides an electric cycle k of the permanent magnet auxiliary synchronous reluctance motor into k Must be greater than or equal to 8; assuming that the one-d axis is on the bisector, assuming that the one-q axis is at a position that is assumed to be 90° electrical angle of the -d axis; while applying the same magnitude to each bisector, the same duration is maintained. Setting the voltage vector of time, sampling the stator winding currents, performing a park conversion to obtain the current response increment of the preset time on the -d axis, the larger the response value of the current response, the assumed d-axis The closer to the actual S pole of the permanent magnet auxiliary synchronous reluctance motor, for initial identification of the initial N/S pole of the rotor; then, the same voltage is applied to the stator windings for the same period of time Vector, restoring the above process, calculating the current response increment in the preset time of the -d axis and assuming that the current response increment of the -q axis within the preset time, the greater the difference between the two, the corresponding The -d axis and the permanent magnet auxiliary synchronous reluctance motor The closer the S pole, the rotor for accurate identification of the initial N / S poles. The method for accurately determining the initial N/S pole of the permanent magnet auxiliary synchronous reluctance motor rotor according to claim 2, wherein the identification method comprises the following steps: Step 1: one electric cycle of the permanent magnet auxiliary synchronous reluctance motor k aliquot, k must be greater than or equal to 8, Δ θ ₀ = 360 ° / k ; assuming the -d axis is on the bisector, assuming that the -q axis is advanced by assuming an angle of 90 ° electrical angle of the -d axis; Applying the voltage vector having the same amplitude and continuing for the same preset time to each aliquot, sampling the stator winding currents, performing a park conversion to assume that the current response increment Δ i in the preset time on the -d axis _d . comparing the voltage vector corresponding to each of the stator windings to assume the -d-axis current response increment Δ i _d , and extracting the maximum current response increment Δ i _{d corresponding} to the first position θ _{1 of the} voltage vector Is a rough position of the actual -d axis (S pole) of the permanent magnet auxiliary synchronous reluctance motor; Step 2: obtaining the coarse position θ ₁ from step 1 and deviating from the coarse position θ _{1 by} ±Δ θ ₀ / The two deviation positions of the electrical angle are respectively applied to the voltage of step 1 Quantity, assuming that the -d axis is at the deviation position, assuming that the -q axis is at a position that is assumed to be 90° electrical angle of the -d axis; sampling the stator winding currents, performing a park conversion to assume that the -d axis Comparing a first current response increment Δ i _{d 1} in a preset time and a second current response increment Δ i _{q 1 in} the preset time period of the -q axis, comparing the first current response increment with the second The current response increment Δ i _d1 -Δ i _{q 1} , and extracting the second position of the voltage vector of the first current response increment and the second current response increment Δ i _d1 -Δ i _{q 1} θ _{2 is} the actual position of the permanent magnet auxiliary synchronous reluctance motor that is closer to the position of the -d axis (S pole); Step 3: Repeat step 2 until the more accurate actual operation of the permanent magnet auxiliary synchronous reluctance motor is obtained. The -d axis (S pole) is a precise position θ _r , and an actual d-axis (N-pole)-actual position θ _{f of} the permanent magnet-assisted synchronous reluctance motor is obtained for an electrical angle of θ _r ±180°.