CN112104290B

CN112104290B - Method and device for identifying initial position of magnetic pole of motor rotor

Info

Publication number: CN112104290B
Application number: CN202010987077.8A
Authority: CN
Inventors: 徐晖; 吴春; 何原明; 文龙; 曾志成
Original assignee: Hangzhou Silan Microelectronics Co Ltd
Current assignee: Hangzhou Silan Microelectronics Co Ltd
Priority date: 2020-09-18
Filing date: 2020-09-18
Publication date: 2023-03-10
Anticipated expiration: 2040-09-18
Also published as: CN112104290A

Abstract

The invention relates to a method for identifying the initial position of a magnetic pole of a motor rotor, which comprises the following steps: injecting different voltage pulses for multiple times, and collecting the terminal voltage of the suspension phase under the different voltage pulses to obtain multiple pairs of collected voltages; respectively calculating corresponding voltage increments of a plurality of pairs of collected voltages; determining a sector in which the rotor magnetic poles may be located according to corresponding voltage increments of the plurality of pairs of collected voltages; calculating terminal voltage variation trend of a suspension phase corresponding to a sector possibly located; the actual sector where the rotor magnetic pole is located is determined according to the terminal voltage change trend, the method for identifying the initial position of the rotor magnetic pole of the motor does not need to use current information, only needs to detect three-phase terminal voltages, and is short in detection time, high in precision and easy to implement.

Description

Method and device for identifying initial position of magnetic pole of motor rotor

Technical Field

The invention relates to the technical field of permanent magnet synchronous motor control, in particular to a method and a device for identifying an initial position of a magnetic pole of a motor rotor.

Background

The permanent magnet synchronous motor has the advantages of small volume, high efficiency, good dynamic performance, high steady-state precision and the like, and is widely applied to various motor driving occasions such as fans, pumps, household appliances, industrial manufacturing and the like. In order to achieve a reliable start of a permanent magnet synchronous motor, it is necessary to obtain an initial position of the rotor poles and then apply the correct voltage vector direction. However, in practice, the position sensor cannot be installed due to constraints of cost, volume and the like. If the initial position of the rotor magnetic pole cannot be obtained, the motor can be started to reversely rotate, and even the motor can be started to fail, which is not allowed in the occasion with higher requirement on starting performance. And for the occasion of installing the incremental photoelectric encoder, an absolute position signal does not exist at the starting moment, and a three-phase Hall position sensor is usually additionally added to determine the initial position of the magnetic pole of the rotor. However, this approach increases system cost and results in more complex position sensor circuitry and reduced reliability. Therefore, a method for identifying the initial position of the rotor magnetic pole of the permanent magnet synchronous motor needs to be researched.

At present, the identification of the initial position usually needs to apply voltage pulses with short acting time and different directions, then the magnitude of bus current in different voltage directions is compared, and the larger the current is, the closer the voltage applying direction is to the position of a rotor magnetic pole; or applying a high-frequency sinusoidal voltage signal, responding to the demodulation position by high-frequency current, and combining a magnetic pole N and S distinguishing method to obtain the initial position of the magnetic pole of the rotor.

However, the above method requires the motor to have a large inductance saliency, i.e., the larger the difference between the inductances of the d and q axes is, the better. In practice, the salient inductance polarity of the surface-mounted permanent magnet synchronous motor is often weak. And a voltage pulse applying mode is adopted, and the bus current sampling is required to be used for overcurrent protection, so that the sampling range is wide, and the resolution is low. Therefore, when voltage pulses in different directions are applied, the bus current difference is not obvious, and the magnetic pole position cannot be accurately identified. If the action time of the voltage pulse is increased, the motor is likely to rotate in the initial position identification process, and the high-reliability starting requirement cannot be met. The high-frequency sinusoidal voltage injection method is adopted to identify the initial position of the magnetic pole of the rotor, a high-precision phase current sensor is needed, the method is not suitable for low-cost application occasions and is also influenced by current detection precision and inductance salient pole rate.

In view of this, a method and an apparatus for accurately determining an initial position of a magnetic pole of a motor rotor are important.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for identifying the initial position of the magnetic pole of the motor rotor, which can avoid the rotation of the rotor in the judging process, effectively shorten the judging time of the initial position of the magnetic pole of the rotor and improve the judging precision.

The invention adopts the technical scheme that the method for identifying the initial position of the magnetic pole of the motor rotor is provided to solve the technical problems, and comprises the following steps: injecting different voltage pulses for multiple times, and collecting the terminal voltage of the suspension phase under the different voltage pulses to obtain multiple pairs of collected voltages; respectively calculating corresponding voltage increments of the multiple pairs of collected voltages; determining a sector in which the rotor magnetic poles may be located according to the corresponding voltage increment of the plurality of pairs of collected voltages; calculating the terminal voltage variation trend of the suspension phase corresponding to the possibly located sector; and determining the actual sector where the rotor magnetic pole is located according to the terminal voltage change trend.

In an embodiment of the invention, each of the plurality of pairs of collecting voltages is a collecting voltage of the same suspended phase under different injection voltage pulses.

In an embodiment of the present invention, the step of determining the sector in which the rotor pole may be located according to the corresponding voltage increment of the plurality of pairs of collected voltages includes: the magnitudes of the corresponding voltage increments of the pairs of collected voltages are compared to determine the sector in which the rotor pole is likely to be located.

In an embodiment of the present invention, the terminal voltage variation trend is a slope of the terminal voltage.

In an embodiment of the present invention, the step of determining the actual sector in which the rotor magnetic pole is located according to the slope of the terminal voltage comprises: and determining the actual sector where the rotor magnetic pole is positioned according to the positive and negative of the slope of the terminal voltage.

In one embodiment of the present invention, at least six different voltage pulses are injected.

In an embodiment of the invention, six different voltage pulses are injected, wherein the first voltage pulse is injected in a mode that a is connected with the positive end of the bus, b is connected with the negative end of the bus, and c is suspended; the second voltage pulse injection mode is that b is connected with the positive end of the bus, a is connected with the negative end of the bus, and c is suspended; the third voltage pulse injection mode is that b is connected with the positive end of the bus, c is connected with the negative end of the bus, and a is suspended; the fourth voltage pulse injection mode is that c is connected with the positive end of the bus, b is connected with the negative end of the bus, and a is suspended; the fifth voltage pulse injection mode is that c is connected with the positive end of the bus, a is connected with the negative end of the bus, and b is suspended; the sixth voltage pulse injection mode is that a is connected with the positive end of the bus, c is connected with the negative end of the bus, and b is suspended.

In an embodiment of the present invention, the sectors include sectors 1 to 12, and the angle of the sectors is 30 degrees.

In an embodiment of the present invention, the six different voltage pulses are injected, the terminal voltages of the suspended phase under the different voltage pulses are respectively collected, three pairs of collected voltages are obtained, which are the a-phase terminal voltage, the b-phase terminal voltage, and the c-phase terminal voltage, and the a-phase terminal voltage increment, the b-phase terminal voltage increment, and the c-phase terminal voltage increment are respectively calculated.

In an embodiment of the invention, the step of determining the sector in which the rotor pole may be located comprises: comparing the voltage increment of the phase a end, the voltage increment of the phase b end and the voltage increment of the phase c end; if the voltage increment of the phase a end is maximum, if the voltage increment of the phase c end is larger than that of the phase b end, the magnetic pole of the rotor is positioned in the

sector

6 or 12, otherwise, the magnetic pole of the rotor is positioned in the

sector

5 or 11; if the voltage increment of the phase b end is maximum, if the voltage increment of the phase a end is larger than the voltage increment of the phase c end, the magnetic pole of the rotor is positioned in the

sector

4 or 10, otherwise, the magnetic pole of the rotor is positioned in the

sector

3 or 9; if the voltage increment of the phase-c end is the largest, if the voltage increment of the phase-b end is larger than that of the phase-a end, the magnetic pole of the rotor is positioned in the

sector

2 or 8, otherwise, the magnetic pole of the rotor is positioned in the sector 1 or 7.

In an embodiment of the present invention, the step of calculating a terminal voltage variation trend of the suspension phase corresponding to the sector where the rotor may be located, and determining an actual sector where the rotor magnetic pole is located according to the terminal voltage variation trend includes: if the position of the rotor magnetic pole is judged to be in the

sector

6 or 12, calculating the slope of the voltage of the phase c end, if the slope of the voltage of the phase c end is judged to be positive, the rotor magnetic pole is positioned in the sector 6, otherwise, the rotor magnetic pole is positioned in the sector 12; if the position of the rotor magnetic pole is judged to be in the sector 1 or 7, calculating the slope of the voltage of the phase c end, if the slope of the voltage of the phase c end is judged to be positive, the rotor magnetic pole is positioned in the sector 1, otherwise, the rotor magnetic pole is positioned in the sector 7; if the magnetic pole position of the rotor is judged to be in the

sector

2 or 8, calculating the slope of the voltage of the phase b end, if the slope of the voltage of the phase b end is judged to be positive, the magnetic pole of the rotor is positioned in the sector 2, otherwise, the magnetic pole of the rotor is positioned in the sector 8; if the position of the rotor magnetic pole is judged to be in the

sector

3 or 9, calculating the slope of the voltage of the phase b end, if the slope of the voltage of the phase b end is judged to be positive, the rotor magnetic pole is positioned in the sector 3, otherwise, the rotor magnetic pole is positioned in the sector 9; if the position of the rotor magnetic pole is judged to be in the

sector

4 or 10, calculating the slope of the voltage of the phase a end, if the slope of the voltage of the phase a end is judged to be positive, the rotor magnetic pole is positioned in the sector 4, otherwise, the rotor magnetic pole is positioned in the sector 10; if the position of the rotor magnetic pole is judged to be in the

sector

5 or 11, calculating the slope of the voltage of the phase a end, if the slope of the voltage of the phase a end is judged to be positive, the rotor magnetic pole is positioned in the sector 5, and if not, the rotor magnetic pole is positioned in the sector 11.

In an embodiment of the invention, the step of determining the sector in which the rotor pole may be located comprises: comparing the voltage increment of the phase a end, the voltage increment of the phase b end and the voltage increment of the phase c end; if the voltage increment of the phase a end is maximum, the magnetic pole of the rotor is positioned in a large sector formed by the

sectors

5 and 6 or a large sector formed by the

sectors

11 and 12; if the voltage increment of the phase b end is maximum, the rotor magnetic pole is positioned in a large sector formed by the

sectors

3 and 4 or a large sector formed by the

sectors

9 and 10; if the voltage increment at the c-phase end is the largest, the rotor magnetic pole is positioned in the large sector formed by the

sectors

1 and 2 or the large sector formed by the sectors 7 and 8.

In an embodiment of the present invention, the step of calculating a terminal voltage variation trend of the suspension phase corresponding to the sector where the rotor magnetic pole may be located, and determining the actual sector where the rotor magnetic pole is located according to the terminal voltage variation trend includes: if the rotor magnetic pole is located in the large sector formed by the

sectors

5 and 6 or the large sector formed by the

sectors

11 and 12, calculating the slope of the voltage at the phase c end, if the slope of the voltage at the phase c end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the

sectors

5 and 6, otherwise, the rotor magnetic pole is located in the large sector formed by the

sectors

11 and 12; if the rotor magnetic pole is located in the large sector formed by the

sectors

3 and 4 or the large sector formed by the

sectors

9 and 10, calculating the slope of the voltage of the phase-a end, if the slope of the voltage of the phase-a end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the

sectors

3 and 4, otherwise, the rotor magnetic pole is located in the large sector formed by the

sectors

9 and 10; if the rotor magnetic pole is located in the large sector formed by the

sectors

1 and 2 or the large sector formed by the sectors 7 and 8, calculating the slope of the voltage at the phase b end, if the slope of the voltage at the phase b end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the

sectors

1 and 2, otherwise, the rotor magnetic pole is located in the large sector formed by the sectors 7 and 8.

In an embodiment of the present invention, the terminal voltage is reduced according to a scaling coefficient and/or filtered according to a filtering coefficient to obtain the plurality of pairs of collected voltages.

In one embodiment of the invention, the rotor poles are positioned to within 30 degrees or 60 degrees by injecting six different voltage pulses.

Another aspect of the present invention provides an apparatus for identifying an initial position of a magnetic pole of a rotor of an electric machine, including: the voltage increment comparison module is configured to acquire the terminal voltage of the suspended phase under different voltage pulses according to the different voltage pulses injected for multiple times so as to obtain multiple pairs of acquired voltages, respectively calculate corresponding voltage increments of the multiple pairs of acquired voltages, and determine a sector where a rotor magnetic pole may be located according to the corresponding voltage increments of the multiple pairs of acquired voltages; and the magnetic pole judging module is configured to calculate the terminal voltage variation trend of the suspension phase corresponding to the possibly located sector, and determine the actual sector where the rotor magnetic pole is located according to the terminal voltage variation trend.

In an embodiment of the present invention, each of the plurality of pairs of collecting voltages is a collecting voltage of the same suspension phase under different injection voltage pulses.

In an embodiment of the present invention, the step of determining, by the voltage increment comparison module, a sector in which a rotor magnetic pole may be located according to the corresponding voltage increment of the plurality of pairs of collected voltages includes: the magnitudes of the corresponding voltage increments of the pairs of collected voltages are compared to determine the sector in which the rotor pole is likely to be located.

In an embodiment of the invention, the terminal voltage variation trend is a slope of the terminal voltage.

In an embodiment of the present invention, the step of determining, by the magnetic pole determining module, an actual sector where a rotor magnetic pole is located according to a slope of the terminal voltage includes: and determining the actual sector where the rotor magnetic pole is positioned according to the positive and negative of the slope of the terminal voltage.

In one embodiment of the invention, six different voltage pulses are injected, wherein the first voltage pulse is injected in a mode that a is connected with the positive end of a bus, b is connected with the negative end of the bus, and c is suspended; the second voltage pulse injection mode is that b is connected with the positive end of the bus, a is connected with the negative end of the bus, and c is suspended; the third voltage pulse injection mode is that b is connected with the positive end of the bus, c is connected with the negative end of the bus, and a is suspended; the fourth time of voltage pulse injection is in a mode that c is connected with the positive end of the bus, b is connected with the negative end of the bus, and a is suspended; the fifth voltage pulse injection mode is that c is connected with the positive end of the bus, a is connected with the negative end of the bus, and b is suspended; the sixth voltage pulse injection mode is that a is connected with the positive end of the bus, c is connected with the negative end of the bus, and b is suspended.

In an embodiment of the present invention, the step of determining, by the voltage increment comparison module, the sector in which the rotor magnetic pole may be located according to the corresponding voltage increment of the plurality of pairs of collected voltages includes: comparing the voltage increment of the phase a end, the voltage increment of the phase b end and the voltage increment of the phase c end; if the voltage increment of the phase a end is maximum, if the voltage increment of the phase c end is larger than that of the phase b end, the magnetic pole of the rotor is positioned in the

sector

6 or 12, otherwise, the magnetic pole of the rotor is positioned in the

sector

4 or 10, otherwise, the magnetic pole of the rotor is positioned in the

sector

In an embodiment of the present invention, the step of calculating, by the magnetic pole determining module, a terminal voltage variation trend of the suspension phase corresponding to the sector where the magnetic pole may be located, and determining the actual sector where the magnetic pole of the rotor is located according to the terminal voltage variation trend, includes: if the position of the rotor magnetic pole is judged to be in the

sector

6 or 12, calculating the slope of the voltage of the phase c end, if the slope of the voltage of the phase c end is judged to be positive, the rotor magnetic pole is positioned in the sector 6, otherwise, the rotor magnetic pole is positioned in the sector 12; if the position of the rotor magnetic pole is judged to be in the sector 1 or 7, calculating the slope of the voltage of the phase c end, if the slope of the voltage of the phase c end is judged to be positive, the rotor magnetic pole is positioned in the sector 1, otherwise, the rotor magnetic pole is positioned in the sector 7; if the position of the rotor magnetic pole is judged to be in the

sector

2 or 8, calculating the slope of the voltage of the phase b end, if the slope of the voltage of the phase b end is judged to be positive, the rotor magnetic pole is positioned in the sector 2, otherwise, the rotor magnetic pole is positioned in the sector 8; if the magnetic pole position of the rotor is judged to be in the

sector

3 or 9, calculating the slope of the voltage of the phase b end, if the slope of the voltage of the phase b end is judged to be positive, the magnetic pole of the rotor is positioned in the sector 3, otherwise, the magnetic pole of the rotor is positioned in the sector 9; if the position of the rotor magnetic pole is judged to be in the

sector

5 or 11, calculating the slope of the voltage of the phase a end, if the slope of the voltage of the phase a end is judged to be positive, the rotor magnetic pole is positioned in the sector 5, otherwise, the rotor magnetic pole is positioned in the sector 11.

In an embodiment of the present invention, the step of determining, by the voltage increment comparison module, the sector in which the rotor magnetic pole may be located according to the corresponding voltage increment of the plurality of pairs of collected voltages includes: comparing the voltage increment of the phase a end, the voltage increment of the phase b end and the voltage increment of the phase c end; if the voltage increment of the phase a end is maximum, the magnetic pole of the rotor is positioned in a large sector formed by the

sectors

5 and 6 or a large sector formed by the

sectors

3 and 4 or a large sector formed by the

sectors

1 and 2 or the large sector formed by the sectors 7 and 8.

In an embodiment of the present invention, the magnetic pole determining module calculates a terminal voltage variation trend of the suspension phase corresponding to the sector where the magnetic pole may be located, and the step of determining the actual sector where the magnetic pole of the rotor is located according to the terminal voltage variation trend includes: if the rotor magnetic pole is located in the large sector formed by the

sectors

5 and 6 or the large sector formed by the

sectors

11 and 12, calculating the slope of the voltage at the c-phase end, if the slope of the voltage at the c-phase end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the

sectors

3 and 4 or the large sector formed by the

sectors

In an embodiment of the present invention, the method further includes: and the voltage measurement module is configured to step down the terminal voltage according to a proportionality coefficient and/or filter the terminal voltage according to a filter coefficient so as to obtain the plurality of pairs of collected voltages.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following remarkable advantages:

the method for identifying the initial position of the magnetic pole of the motor rotor determines the sector where the magnetic pole of the motor rotor can be located according to the corresponding voltage increment of a plurality of pairs of collected voltages, and determines the actual sector where the magnetic pole of the motor rotor is located by calculating the terminal voltage change trend of the corresponding suspension phase of the sector where the magnetic pole of the motor rotor can be located. The method for cutting off the initial position of the magnetic pole of the motor rotor can not only avoid the rotor from rotating in the judging process, but also effectively shorten the judging time of the initial position of the magnetic pole of the rotor and improve the judging precision.

The invention can position the rotor magnetic pole position within 60 degrees without current information, and further can position the rotor magnetic pole position within 60 degrees. The method for identifying the initial position of the magnetic pole of the motor rotor only needs to detect the three-phase terminal voltage without using current information, has short detection time and high precision, and is easy to realize.

Drawings

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below, wherein:

fig. 1 is a flowchart of a method for identifying an initial position of a magnetic pole of a motor rotor according to an embodiment of the invention;

fig. 2 is a schematic structural diagram of a voltage measurement module of an apparatus for identifying an initial position of a magnetic pole of a motor rotor according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of the voltage vector direction and the sector of a method for identifying the initial position of the magnetic pole of the motor rotor according to an embodiment of the present invention;

FIG. 4 is a simplified schematic diagram of a motor system with an injected voltage pulse of a + b according to an embodiment of the present invention;

fig. 5 is a waveform diagram of a relationship between three-phase terminal voltages and rotor magnetic pole positions of a method for identifying an initial position of a magnetic pole of a motor rotor according to an embodiment of the present invention;

FIG. 6 is a waveform diagram of the injection voltage pulse and the rotor magnetic pole position of a method for identifying the initial position of the rotor magnetic pole of the motor according to an embodiment of the present invention;

fig. 7 is a diagram illustrating an experimental result when the rotor magnetic pole is at 0 degrees according to an embodiment of the present invention;

fig. 8 is a diagram illustrating an experimental result when the rotor magnetic pole is located at 180 degrees according to an embodiment of the present invention;

fig. 9 is a schematic view of an apparatus for identifying an initial position of a magnetic pole of a motor rotor according to an embodiment of the invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described herein, and thus the present invention is not limited to the specific embodiments disclosed below.

As used in this application and the appended claims, the terms "a," "an," "the," and/or "the" are not intended to be inclusive in the singular, but rather are intended to be inclusive in the plural unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" are intended to cover only the explicitly identified steps or elements as not constituting an exclusive list and that the method or apparatus may comprise further steps or elements.

In describing the embodiments of the present invention in detail, the cross-sectional views illustrating the structure of the device are not enlarged partially in a general scale for convenience of illustration, and the schematic drawings are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.

For convenience in description, spatial relational terms, such as "below," "beneath," "lower," "below," "over," "upper," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatial relationship terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary words "below" and "beneath" can encompass both an orientation of up and down. The device may have other orientations (rotated 90 degrees or at other orientations) and the spatial relationship descriptors used herein should be interpreted accordingly. Further, it will also be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

In the context of this application, a structure described as having a first feature "on" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed in between the first and second features, such that the first and second features may not be in direct contact.

It will be understood that when an element is referred to as being "on," "connected to," "coupled to" or "contacting" another element, it can be directly on, connected or coupled to, or contacting the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly on," "directly connected to," "directly coupled to" or "directly contacting" another element, there are no intervening elements present. Similarly, when a first component is said to be "in electrical contact with" or "electrically coupled to" a second component, there is an electrical path between the first component and the second component that allows current to flow. The electrical path may include capacitors, coupled inductors, and/or other components that allow current to flow even without direct contact between the conductive components.

The following embodiments of the invention provide a method for identifying the initial position of the magnetic pole of the motor rotor, which can avoid the rotor from rotating in the judging process, effectively shorten the judging time of the initial position of the magnetic pole of the rotor, and improve the judging precision.

The invention discloses a method for identifying the initial position of a magnetic pole of a motor rotor, which comprises the following steps: injecting different voltage pulses for multiple times, and collecting the terminal voltage of the suspension phase under the different voltage pulses to obtain multiple pairs of collected voltages; respectively calculating corresponding voltage increments of a plurality of pairs of collected voltages; determining sectors in which the magnetic poles of the rotor are possibly positioned according to corresponding voltage increments of a plurality of pairs of collected voltages; calculating the terminal voltage variation trend of the suspension phase corresponding to the sector where the suspension phase is possibly located; and determining the actual sector where the rotor magnetic pole is positioned according to the terminal voltage change trend.

Fig. 1 is a flowchart of a method for identifying an initial position of a magnetic pole of a motor rotor according to an embodiment of the invention. The method is described below with reference to fig. 1. It is to be understood that the following description is merely exemplary, and that variations may be made by those skilled in the art without departing from the spirit of the invention.

And step 110, injecting different voltage pulses for multiple times, and collecting the terminal voltage of the suspension phase under the different voltage pulses to obtain multiple pairs of collected voltages.

In an embodiment of the invention, each of the plurality of pairs of collected voltages is a collected voltage of the same suspended phase under different injection voltage pulses.

For example, the electric machine may be configured to receive multiple injection voltage pulses and to generate pairs of collected voltages from the received multiple injection voltage pulses, the pairs of collected voltages being terminal voltages of the suspended phase.

In some embodiments of the invention, the different voltage pulses injected into the motor multiple times may include at least six different voltage pulses.

Preferably, the six-time voltage pulse form injected into the motor may include, but is not limited to, the following pulse forms:

the first voltage pulse is a + b-, namely a is connected with the positive end of the bus, b is connected with the negative end of the bus, and c is suspended; the second voltage pulse is b + a-, namely b is connected with the positive end of the bus, a is connected with the negative end of the bus, and c is suspended; the third voltage pulse is b + c-, namely b is connected with the positive end of the bus, c is connected with the negative end of the bus, and a is suspended; the fourth voltage pulse is c + b-, namely c is connected with the positive end of the bus, b is connected with the negative end of the bus, and a is suspended; the fifth voltage pulse is c + a-, namely c is connected with the positive end of the bus, a is connected with the negative end of the bus, and b is suspended; the sixth voltage pulse is a + c-, namely a is connected with the positive end of the bus, c is connected with the negative end of the bus, and b is suspended.

It should be understood that the number of voltage pulses injected into the motor can be adjusted by one skilled in the art according to actual needs, and the invention is not limited thereto.

In one non-limiting example, the collection voltage u resulting from the first voltage pulse injection may be separately recorded _cG1 (ii) a Recording the collection voltage u generated by the second voltage pulse injection _cG2 (ii) a Recording the acquisition voltage u generated by the third voltage pulse injection _aG1 (ii) a Recording the collected voltage u generated by the fourth voltage pulse injection _aG2 (ii) a Recording the collection voltage u generated by the fifth voltage pulse injection _bG1 (ii) a Recording the collection voltage u generated by the sixth voltage pulse injection _bG2 。

In some embodiments, in order to improve the accuracy of the acquisition voltage, it is necessary to perform acquisition after a certain time of the injection voltage pulse, so as to avoid voltage oscillation during the establishment of the acquisition voltage.

In the present embodiment, each pair of the collected voltages is the collected voltage of the same suspended phase under different injection voltage pulses. For example, the phases c are suspended when the first voltage pulse and the second voltage pulse are injected, the phases a are suspended when the third voltage pulse and the fourth voltage pulse are injected, and the phases c are suspended when the fifth voltage pulse and the sixth voltage pulse are injected. Therefore, the first voltage pulse and the second voltage pulse, the third voltage pulse and the fourth voltage pulse, and the fifth voltage pulse and the sixth voltage pulse are a pair of collecting voltages respectively.

Step 120, calculating corresponding voltage increments of the plurality of pairs of collected voltages, respectively.

In some examples, increments of the collected voltages for the same suspended phase of the plurality of collected voltages may be calculated to yield a plurality of voltage increments.

In an embodiment of the present invention, six different voltage pulses are injected, the terminal voltages of the suspended phase under the different voltage pulses are respectively collected, three pairs of collected voltages are obtained, which are the a-phase terminal voltage, the b-phase terminal voltage, and the c-phase terminal voltage, and the a-phase terminal voltage increment, the b-phase terminal voltage increment, and the c-phase terminal voltage increment are respectively calculated.

For example, the voltage increment of each of the three pairs of collected voltages may be calculated to obtain the corresponding voltage increment, respectively, that is: Δ u _cG ＝u _cG1 -u _cG2 ；Δu _aG ＝u _aG1 -u _aG2 ；Δu _bG ＝u _bG1 -u _bG2 。

In some embodiments of the present invention, step 110 may be preceded by: and reducing the terminal voltage according to the proportionality coefficient and/or filtering the terminal voltage according to the filter coefficient to obtain a plurality of pairs of collected voltages.

The collected voltages may be stepped down and/or filtered according to a scaling factor and/or a filtering factor, respectively, before calculating the voltage increment for each of the plurality of pairs of collected voltages to obtain a plurality of voltage increments.

It can be understood that the step-down and/or the filtering of the collected voltage may be implemented by a voltage measurement module formed by a voltage dividing resistor and an RC filter, but the application is not limited thereto.

Fig. 2 is a schematic structural diagram of a voltage measurement module of an apparatus for identifying an initial position of a magnetic pole of a motor rotor according to an embodiment of the present invention.

Referring to FIG. 2, the voltage measuring module is composed of two voltage dividing resistors R ₁ And R ₂ And a capacitor C ₁ A voltage division and Low Pass Filter (LPF) circuit is formed, so that the voltage to ground of a three-phase port of the motor can be detected in real time. The terminal voltage information after voltage reduction and filtering is sent to an analog-to-digital converter (ADC) and processed by the ADC to be used as acquisition voltage.

It should be noted that a voltage measurement module as shown in FIG. 2 may be employed for a non-isolated driver; for the isolated driver, an electrical isolation device such as an isolation operational amplifier needs to be added before entering the ADC.

In some examples, the scaling factor may satisfy the following equation:

wherein G is _V Is a proportionality coefficient, R ₁ And R ₂ Respectively the resistance values of the two divider resistors.

Preferably, the voltage attenuation gain is selected by considering the bus voltage and the ADC range, and in order to improve the voltage identification accuracy, the preferred proportionality coefficient is:

wherein, U _ADCmax To maximize the available voltage, U _dc For rated bus voltage, M _V For collecting voltage margin.

Collecting voltage margin M _V It may be preferred to be 1.2, i.e. 1.2 times the bus voltage may be collected.

In some examples, the selection of the resistance values of the two voltage dividing resistors is required to satisfy the voltage attenuation gainWhile taking into account the rated power consumption of the resistor, R can be set ₁ 、R ₂ The resistors are divided into a plurality of resistors of the same type in series connection, and the rated power of the single resistor is reduced.

In some examples, the filter coefficients may satisfy the following equation:

wherein R is _p ＝(R ₁ R ₂ )/(R ₁ +R ₂ )，f _LPF Is a filter coefficient, R ₁ And R ₂ Respectively the resistance values of two divider resistors, C ₁ Is a capacitance value.

The filter coefficient refers to the cut-off frequency of the first order low pass filter. Preferably, in order to improve the voltage identification accuracy and avoid the influence of low-pass filtering delay on the system, f can be used _LPF Set to about one-half of the Pulse Width Modulation (PWM) frequency.

The acquired voltage is attenuated according to a designed proportionality coefficient, so that the voltage acquisition range requirement of the ADC can be met. Meanwhile, the filter coefficient is adopted to filter the voltage, so that the signal noise of the collected voltage can be weakened.

In step 130, the sectors in which the rotor poles may be located are determined based on the corresponding voltage increments of the pairs of collected voltages.

For example, the magnitudes of the voltage increments may be compared based on the voltage increments obtained in step 120, and the (opposite) two sectors of the plurality of sectors in which the motor rotor poles are located may be determined based on the voltage increments.

In one embodiment of the present invention, the sectors include sectors 1 to 12, and the angle of the sectors is 30 degrees.

Fig. 3 is a schematic diagram of voltage vector directions and sectors of a method for identifying an initial position of a magnetic pole of a motor rotor according to an embodiment of the invention. Referring to fig. 3, the initial position of the rotor magnetic pole may be divided into 12 sectors, sector 1 to sector 12 respectively, and each sector angle is 30 degrees, according to six voltage pulses injected into the motor.

In an embodiment of the present invention, the step of determining the sector in which the rotor pole may be located according to the corresponding voltage increment of the plurality of pairs of collected voltages comprises: the magnitudes of the corresponding voltage increments for the pairs of collected voltages are compared to determine the sector in which the rotor poles may be located.

For example, for the case of injecting six voltage pulses, three voltage increments Δ u may be compared _aG 、Δu _bG And Δ u _cG The size of (2):

Δu _max ＝max{Δu _aG ,Δu _bG ,Δu _cG } (4)

in a first embodiment of the invention, the step of determining the sectors in which the rotor poles may be located comprises:

comparing the voltage increment of the phase a end, the voltage increment of the phase b end and the voltage increment of the phase c end; if the voltage increment of the phase a end is maximum, if the voltage increment of the phase c end is larger than that of the phase b end, the magnetic pole of the rotor is positioned in the

sector

6 or 12, otherwise, the magnetic pole of the rotor is positioned in the

sector

4 or 10, otherwise, the magnetic pole of the rotor is positioned in the

sector

3 or 9; if the voltage increment of the phase c end is the maximum, if the voltage increment of the phase b end is larger than that of the phase a end, the magnetic pole of the rotor is positioned in the

sector

Illustratively, if Δ u _max Is Δ u _aG Then further determine Δ u _cG ＞Δu _bG If this is true, the rotor pole is located in

sector

6 or 12, otherwise in

sector

5 or 11.

If Δ u _max Is Δ u _bG Then further determine Δ u _aG ＞Δu _cG If this is true, the rotor pole is located in

sector

4 or 10, otherwise in

sector

3 or 9.

If Δ u _max Is Δ u _cG Then further determine Δ u _bG ＞Δu _aG If this is true, the rotor pole is located in

sector

2 or 8, otherwise in sector 1 or 7.

In a second embodiment of the invention, the step of determining the sectors in which the rotor poles may be located comprises:

comparing the voltage increment of the phase a end, the voltage increment of the phase b end and the voltage increment of the phase c end; if the voltage increment of the phase a end is maximum, the magnetic pole of the rotor is positioned in a large sector formed by the

sectors

5 and 6 or a large sector formed by the

sectors

3 and 4 or a large sector formed by the

sectors

9 and 10; if the voltage increment at the phase-c end is the largest, the rotor magnetic pole is positioned in the large sector formed by the

sectors

1 and 2 or the large sector formed by the sectors 7 and 8.

Illustratively, if Δ u _max Is Δ u _aG The rotor poles are located in the large sector formed by

sectors

5 and 6 or the large sector formed by

sectors

11 and 12.

If Δ u _max Is Δ u _bG The rotor poles are then located in the large sector formed by

sectors

3 and 4 or the large sector formed by

sectors

9 and 10.

If Δ u _max Is Δ u _cG The rotor poles are then located in the large sector formed by

sectors

1 and 2 or in the large sector formed by sectors 7 and 8.

Referring to fig. 3, through the above-mentioned voltage increment magnitude and polarity determination, the sectors in which the rotor magnetic poles are located can be reduced from twelve to two opposite sectors.

The following describes the specific principle of determining the position of the magnetic pole of the rotor according to the voltage increment in detail with reference to the following formula:

first, a voltage increment expression under the action of multiple voltage pulses is obtained. For a permanent magnet synchronous motor, assuming sinusoidal distribution of three-phase windings, a motor stator voltage equation can be established:

wherein, the first and the second end of the pipe are connected with each other,

respectively representing stator voltage, stator current and stator flux linkage vectors; r _s Is stator resistance, p is differential operator; abc denotes a three-phase stator coordinate system.

Can be expressed as:

wherein the content of the first and second substances,

is a matrix of stator inductances which are,

is a vector of the permanent magnet flux linkage on the abc coordinate system.

Can be expressed as:

wherein, L and M respectively represent self inductance and mutual inductance of the stator.

Establishing a three-phase terminal voltage equation comprises the following steps:

wherein u is _aG 、u _bG 、u _cG Terminal voltages of three phases a, b, c, respectively, e _a 、e _b 、e _c A, b and b respectively,c, three-phase rotary counter electromotive force; u. of _NG Is the neutral point voltage.

For the case of injecting six voltage pulses, assume that the first voltage pulse is applied, the a-phase winding is positive, the b-phase winding is grounded, and the c-phase is floating.

Fig. 4 is a simplified schematic diagram of a motor system with an injected voltage pulse of a + b according to an embodiment of the present invention.

From the schematic shown in fig. 4, it can be derived:

since the motor is stationary, the three-phase back emf is zero, respectively, i.e.:

e _a ＝0、e _b ＝0、e _c ＝0 (12)

substituting equations (11) and (12) into equations (8) and (9), and equations (8) + (9), the neutral point voltage can be reached:

substituting equations (11) to (13) into equation (10) may make the phase c phase voltage of the suspended phase:

similarly, applying a second voltage pulse comprises:

applying a third voltage pulse having:

applying a fourth voltage pulse having:

a fifth voltage pulse is applied with:

applying a sixth voltage pulse having:

fig. 5 is a waveform diagram of a relationship between three-phase terminal voltages and rotor magnetic pole positions of a method for identifying an initial position of a magnetic pole of a motor rotor according to an embodiment of the present invention.

Referring to fig. 5, three-phase terminal voltages of the motor exist U _dc Offset of/2, and in U _dc The sine regular fluctuation is performed near/2, and the terminal voltage can be compared with U _dc And 2, determining the sector where the rotor magnetic pole is located.

Fig. 6 is a waveform diagram of the injection voltage pulse and the rotor magnetic pole position in a method for identifying the initial position of the rotor magnetic pole of the motor according to an embodiment of the invention. Referring to fig. 6, the comparison of the voltage increments can determine that the rotor pole position may be located in one of the two

sectors

6 or 12.

And step 140, calculating the terminal voltage variation trend of the suspension phase corresponding to the sector possibly located.

In an embodiment of the present invention, the terminal voltage trend is a slope of the terminal voltage.

In some examples, a slope of terminal voltage of a suspension phase may be calculated for a plurality of sectors. In other examples, the slope of the terminal voltages of all phases corresponding to the plurality of sectors may also be calculated.

After determining two possible sectors from the voltage increment in step 130, it is necessary to further distinguish which of the two sectors the rotor pole is located in. Therefore, the slope of the collected voltages of the two sectors needs to be calculated first to further distinguish the N and S poles of the rotor magnetic poles.

And 150, determining the actual sector where the rotor magnetic pole is located according to the terminal voltage change trend.

In this embodiment, it can be determined from the slope of the terminal voltage that the rotor magnetic pole is located in one of the two opposite sectors.

Referring to fig. 6, in order to further determine which one of the two

sectors

6 and 12 the rotor magnetic pole is in, it is necessary to calculate the floating phase terminal voltage u according to equation (14) when the first voltage pulse is injected _cG Slope of (d):

if the error between the direction of the injected voltage and the direction of the rotor magnetic pole is within 90 degrees, the d-axis current will increase with the increase of the voltage acting time, resulting in the reduction of the d-axis inductance, and therefore, L _Δ And is increased. Assume a short time period pi _a If it remains unchanged, u _cG Will rise with a positive slope. Conversely, if the rotor magnetic pole position exceeds 90 degrees from the injection voltage vector direction, a negative d-axis current will be generated, resulting in an increase in d-axis inductance and thus L _Δ And decrease. Suppose pi for a short time _a If it remains unchanged, u _cG Will decrease with a negative slope.

Therefore, if u is judged _cG The slope is positive, the rotor pole is located in sector 6, otherwise it is located in sector 12. Similarly, the initial positions of the magnetic poles of the rotor under other conditions can be sequentially judged.

In the first embodiment of the present invention, the step of calculating the terminal voltage variation trend of the suspension phase corresponding to the sector where the rotor magnetic pole may be located and determining the actual sector where the rotor magnetic pole is located according to the terminal voltage variation trend includes:

if the position of the rotor magnetic pole is judged to be in the sector 6 or 12, calculating the slope of the voltage of the phase c end, if the slope of the voltage of the phase c end is judged to be positive, the rotor magnetic pole is positioned in the sector 6, otherwise, the rotor magnetic pole is positioned in the sector 12; if the position of the rotor magnetic pole is judged to be in the sector 1 or 7, calculating the slope of the voltage of the phase c end, if the slope of the voltage of the phase c end is judged to be positive, the rotor magnetic pole is positioned in the sector 1, otherwise, the rotor magnetic pole is positioned in the sector 7; if the position of the rotor magnetic pole is judged to be in the sector 2 or 8, calculating the slope of the voltage of the phase b end, if the slope of the voltage of the phase b end is judged to be positive, the rotor magnetic pole is positioned in the sector 2, otherwise, the rotor magnetic pole is positioned in the sector 8; if the position of the rotor magnetic pole is judged to be in the sector 3 or 9, calculating the slope of the voltage of the phase b end, if the slope of the voltage of the phase b end is judged to be positive, the rotor magnetic pole is positioned in the sector 3, otherwise, the rotor magnetic pole is positioned in the sector 9; if the position of the rotor magnetic pole is judged to be in the sector 4 or 10, calculating the slope of the voltage of the phase a end, if the slope of the voltage of the phase a end is judged to be positive, the rotor magnetic pole is positioned in the sector 4, otherwise, the rotor magnetic pole is positioned in the sector 10; if the position of the rotor magnetic pole is judged to be in the sector 5 or 11, calculating the slope of the voltage of the phase a end, if the slope of the voltage of the phase a end is judged to be positive, the rotor magnetic pole is positioned in the sector 5, and if not, the rotor magnetic pole is positioned in the sector 11.

For example, if the rotor magnetic pole position is determined to be in

sector

6 or 12, u is calculated _cG If u is judged _cG If the slope is positive, the rotor magnetic pole is located in sector 6, otherwise, the rotor magnetic pole is located in sector 12;

if the voltage increment comparison module judges that the magnetic pole position of the rotor is in the sector 1 or 7, u is calculated _cG If u is judged _cG The slope is positive, the rotor pole is located in sector 1, otherwise it is located in sector 7.

If the voltage increment comparison module judges that the position of the magnetic pole of the rotor is in the

sector

2 or 8, calculating u _bG If u is judged _bG The slope is positive, the rotor pole is located in sector 2, otherwise it is located in sector 8.

If the voltage increment comparison module judges that the magnetic pole position of the rotor is in the

sector

3 or 9, u is calculated _bG If u is judged _bG Slope ofPositive then the rotor pole is in sector 3 and otherwise in sector 9.

sector

4 or 10, calculating u _aG If u is judged _aG The slope is positive, the rotor pole is located in sector 4, otherwise it is located in sector 10.

sector

5 or 11, calculating u _aG If u is judged _aG The slope is positive, the rotor pole is located in sector 5, otherwise it is located in sector 11.

In a second embodiment of the present invention, the step of calculating the terminal voltage variation trend of the suspension phase corresponding to the sector where the rotor magnetic pole may be located, and determining the actual sector where the rotor magnetic pole is located according to the terminal voltage variation trend includes:

if the rotor magnetic pole is located in the large sector formed by the sectors 5 and 6 or the large sector formed by the sectors 11 and 12, calculating the slope of the voltage at the c-phase end, if the slope of the voltage at the c-phase end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the sectors 5 and 6, otherwise, the rotor magnetic pole is located in the large sector formed by the sectors 11 and 12; if the rotor magnetic pole is located in the large sector formed by the sectors 3 and 4 or the large sector formed by the sectors 9 and 10, calculating the slope of the voltage of the phase-a end, if the slope of the voltage of the phase-a end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the sectors 3 and 4, otherwise, the rotor magnetic pole is located in the large sector formed by the sectors 9 and 10; if the rotor magnetic pole is located in the large sector formed by the sectors 1 and 2 or the large sector formed by the sectors 7 and 8, calculating the slope of the voltage of the phase b end, if the slope of the voltage of the phase b end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the sectors 1 and 2, otherwise, the rotor magnetic pole is located in the large sector formed by the sectors 7 and 8.

Illustratively, if the rotor poles are located in the large sector formed by

sectors

5 and 6 or the large sector formed by

sectors

11 and 12, u is calculated _cG If u is judged _cG The slope is positive, the rotor poles are located in the large sector formed by

sectors

5 and 6, and otherwise in the large sector formed by

sectors

11 and 12.

If the rotor poles are located in the large sector formed by

sectors

3 and 4 or the large sector formed by

sectors

9 and 10, u is calculated _aG If u is judged _aG The slope is positive, the rotor poles are located in the large sector formed by

sectors

3 and 4, and otherwise in the large sector formed by

sectors

9 and 10.

If the rotor pole is located in the large sector formed by

sectors

1 and 2 or in sectors 7 and 8, u is calculated _bG If u is judged _bG The slope is positive, the rotor poles are in the large sector formed by

sectors

1 and 2, otherwise in the large sector formed by sectors 7 and 8.

In the above embodiment of the invention, the rotor poles can be positioned to be within the range of 30 degrees or 60 degrees by injecting six different voltage pulses.

It should be understood that the flowchart shown in fig. 1 is used herein to illustrate the steps/operations performed by the method for identifying the initial position of a magnetic pole of a rotor of an electric machine according to an embodiment of the present application. It should be understood that these steps/operations are not necessarily performed in the exact order in which they are performed. Rather, various steps/operations may be processed in reverse order or concurrently. Meanwhile, other steps/operations are either added to or removed from these processes.

Fig. 7 is a diagram illustrating an experimental result when the rotor magnetic pole is at 0 degree according to an embodiment of the present invention.

Referring to fig. 7, six injection voltage pulses are applied when the rotor pole position is at 0 degrees, the first a + b-, the second b + a-, the third b + c-, the fourth c + b-, the fifth c + a-, and the sixth a + c-in fig. 7, respectively. Six acquisition voltages are respectively acquisition voltages u generated by the first voltage pulse injection _cG1 The second voltage pulse injection generates the collection voltage u _cG2 The third voltage pulse injection generates the collection voltage u _aG1 The acquisition voltage u generated by the fourth voltage pulse injection _aG2 The fifth voltage pulse injection generates the collection voltage u _bG1 The acquisition voltage u generated by the sixth voltage pulse injection _bG2 。

By comparing the voltage increments, Δ u is calculated _cG ，Δu _aG ，Δu _bG And comparing the three values to obtain a relationship of Δ u _cG >Δu _aG >Δu _bG Therefore, it can be preliminarily determined that the rotor magnetic pole is located in sector 1 or sector 7.

Further, due to u _cG If the voltage rises, i.e. the slope of the terminal voltage is positive, it is determined that the initial position of the rotor magnetic pole is in sector 1. The judgment result of the rotor magnetic pole position is consistent with the actual value, which shows that the method is adopted to judge the effectiveness of the initial position of the rotor magnetic pole.

Fig. 8 is a diagram illustrating an experimental result when the rotor magnetic pole is located at 180 degrees according to an embodiment of the present invention.

Referring to fig. 8, six injection voltage pulses are applied when the rotor pole position is 180 degrees, as shown in fig. 8 for the first a + b-, the second b + a-, the third b + c-, the fourth c + b-, the fifth c + a-, and the sixth a + c-, respectively. Six acquisition voltages are respectively acquisition voltages u generated by the first voltage pulse injection _cG1 The collection voltage u generated by the second voltage pulse injection _cG2 The acquisition voltage u generated by the third time of voltage pulse injection _aG1 The acquisition voltage u generated by the fourth voltage pulse injection _aG2 The fifth voltage pulse injection generates the collection voltage u _bG1 The collection voltage u generated by the sixth voltage pulse injection _bG2 。

By comparing the voltage increments, Δ u is calculated _cG ，Δu _aG ，Δu _bG And comparing the magnitude relationship of the three values to be delta u _cG >Δu _aG >Δu _bG It can thus be preliminarily determined that the rotor magnetic pole is located in sector 1 or sector 7.

Further, since u _cG And if the voltage drops, namely the slope of the terminal voltage is negative, the initial position of the rotor magnetic pole is judged to be in the sector 7. The judgment result of the rotor magnetic pole position is consistent with the actual value, which shows that the method is adopted to judge the initial position of the rotor magnetic pole to be effective.

On the other hand, referring to fig. 7 and 8, the terminal voltage can be established for a very short time after the voltage pulse injection, for example, less than 40us. Therefore, the method for identifying the initial position of the magnetic pole of the motor rotor can reduce the action time of the voltage pulse, thereby avoiding the rotor from rotating in the judging process.

In addition, the method for identifying the initial position of the rotor magnetic pole of the motor can finally position the initial position of the rotor magnetic pole into a specific sector. For example, six voltage pulse injections may position the rotor magnetic pole within a range of 60 degrees without using current information, and further, the rotor magnetic pole may be positioned within a range of 30 degrees, whereas the rotor magnetic pole position obtained by the conventional six voltage pulse injection detection six bus current determination method is within a range of 60 degrees. Therefore, the invention can further improve the identification precision of the initial position of the rotor magnetic pole.

The method for identifying the initial position of the magnetic pole of the motor rotor only needs to detect the three-phase terminal voltage without using current information, has short detection time, can finally position the initial position of the magnetic pole of the rotor in a sector range, has high judgment precision and is easy to realize.

The embodiment of the invention provides a method for identifying the initial position of the magnetic pole of the motor rotor, which can avoid the rotation of the rotor in the judging process, effectively shorten the judging time of the initial position of the magnetic pole of the rotor and improve the judging precision.

The invention provides a device for identifying the initial position of the magnetic pole of the motor rotor, which can avoid the rotation of the rotor in the judging process, effectively shorten the judging time of the initial position of the magnetic pole of the rotor and improve the judging precision.

Fig. 9 is a schematic view of an apparatus for identifying an initial position of a magnetic pole of a motor rotor according to an embodiment of the invention. Referring to fig. 9, the device 900 for identifying the initial position of the magnetic pole of the motor rotor includes a voltage increment comparison module 920 and a magnetic pole determination module 930.

The voltage increment comparison module 920 is configured to collect terminal voltages of the suspended phases under different voltage pulses according to the different voltage pulses injected for multiple times to obtain multiple pairs of collected voltages, calculate corresponding voltage increments of the multiple pairs of collected voltages respectively, and determine a sector where a rotor magnetic pole may be located according to the corresponding voltage increments of the multiple pairs of collected voltages. The magnetic pole determining module 930 is configured to calculate a terminal voltage variation trend of the suspension phase corresponding to the sector where the magnetic pole may be located, and determine an actual sector where the magnetic pole of the rotor is located according to the terminal voltage variation trend.

In an embodiment of the present invention, each of the plurality of pairs of collected voltages is a collected voltage of the same suspended phase under different injection voltage pulses.

In an embodiment of the present invention, the step of the voltage increment comparing module 920 determining the sector where the rotor magnetic pole may be located according to the corresponding voltage increment of the plurality of pairs of collected voltages includes: the magnitudes of the corresponding voltage increments for the pairs of collected voltages are compared to determine the sector in which the rotor poles may be located.

In an embodiment of the present invention, the step of the magnetic pole determining module 930 determining the actual sector where the rotor magnetic pole is located according to the slope of the terminal voltage includes: and determining the actual sector where the rotor magnetic pole is positioned according to the positive and negative of the slope of the terminal voltage.

In an embodiment of the invention, six different voltage pulses are injected, wherein the first voltage pulse is injected in a mode that a is connected with the positive end of the bus, b is connected with the negative end of the bus, and c is suspended; the second voltage pulse injection mode is that b is connected with the positive end of the bus, a is connected with the negative end of the bus, and c is suspended; the third voltage pulse injection mode is that b is connected with the positive end of the bus, c is connected with the negative end of the bus, and a is suspended; the fourth time of voltage pulse injection is in a mode that c is connected with the positive end of the bus, b is connected with the negative end of the bus, and a is suspended; the fifth voltage pulse injection mode is that c is connected with the positive end of the bus, a is connected with the negative end of the bus, and b is suspended; the sixth voltage pulse injection mode is that a is connected with the positive end of the bus, c is connected with the negative end of the bus, and b is suspended.

In the first embodiment of the present invention, the step of the voltage increment comparison module 920 determining the sector in which the rotor magnetic pole may be located includes: comparing the voltage increment of the phase a end, the voltage increment of the phase b end and the voltage increment of the phase c end; if the voltage increment of the phase a end is maximum, if the voltage increment of the phase c end is larger than that of the phase b end, the magnetic pole of the rotor is positioned in the sector 6 or 12, otherwise, the magnetic pole of the rotor is positioned in the sector 5 or 11; if the voltage increment of the phase b end is maximum, if the voltage increment of the phase a end is larger than the voltage increment of the phase c end, the magnetic pole of the rotor is positioned in the sector 4 or 10, otherwise, the magnetic pole of the rotor is positioned in the sector 3 or 9; if the voltage increment of the phase c end is the maximum, if the voltage increment of the phase b end is larger than that of the phase a end, the magnetic pole of the rotor is positioned in the sector 2 or 8, otherwise, the magnetic pole of the rotor is positioned in the sector 1 or 7.

In the first embodiment of the present invention, the magnetic pole determining module 930 calculates a terminal voltage variation trend of the suspension phase corresponding to the sector where the magnetic pole may be located, and the step of determining the actual sector where the magnetic pole of the rotor is located according to the terminal voltage variation trend includes: if the magnetic pole position of the rotor is judged to be in the sector 6 or 12, calculating the slope of the voltage of the phase c end, if the slope of the voltage of the phase c end is judged to be positive, the magnetic pole of the rotor is positioned in the sector 6, otherwise, the magnetic pole of the rotor is positioned in the sector 12; if the magnetic pole position of the rotor is judged to be in the sector 1 or 7, calculating the slope of the voltage of the phase c end, if the slope of the voltage of the phase c end is judged to be positive, the magnetic pole of the rotor is positioned in the sector 1, otherwise, the magnetic pole of the rotor is positioned in the sector 7; if the position of the rotor magnetic pole is judged to be in the sector 2 or 8, calculating the slope of the voltage of the phase b end, if the slope of the voltage of the phase b end is judged to be positive, the rotor magnetic pole is positioned in the sector 2, otherwise, the rotor magnetic pole is positioned in the sector 8; if the position of the rotor magnetic pole is judged to be in the sector 3 or 9, calculating the slope of the voltage of the phase b end, if the slope of the voltage of the phase b end is judged to be positive, the rotor magnetic pole is positioned in the sector 3, otherwise, the rotor magnetic pole is positioned in the sector 9; if the position of the rotor magnetic pole is judged to be in the sector 4 or 10, calculating the slope of the voltage of the phase a end, if the slope of the voltage of the phase a end is judged to be positive, the rotor magnetic pole is positioned in the sector 4, otherwise, the rotor magnetic pole is positioned in the sector 10; if the position of the rotor magnetic pole is judged to be in the sector 5 or 11, calculating the slope of the voltage of the phase a end, if the slope of the voltage of the phase a end is judged to be positive, the rotor magnetic pole is positioned in the sector 5, otherwise, the rotor magnetic pole is positioned in the sector 11.

In the second embodiment of the present invention, the step of the voltage increment comparison module 920 determining the sector in which the rotor magnetic pole may be located includes: comparing the voltage increment of the phase a end, the voltage increment of the phase b end and the voltage increment of the phase c end; if the voltage increment of the phase a end is maximum, the magnetic pole of the rotor is positioned in a large sector formed by the

sectors

5 and 6 or a large sector formed by the

sectors

3 and 4 or a large sector formed by the

sectors

1 and 2 or the large sector formed by the sectors 7 and 8.

In the second embodiment of the present invention, the magnetic pole determining module 930 calculates a terminal voltage variation trend of the suspension phase corresponding to the sector where the magnetic pole may be located, and the step of determining the actual sector where the magnetic pole of the rotor is located according to the terminal voltage variation trend includes: if the rotor magnetic pole is located in the large sector formed by the sectors 5 and 6 or the large sector formed by the sectors 11 and 12, calculating the slope of the voltage at the phase c end, if the slope of the voltage at the phase c end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the sectors 5 and 6, otherwise, the rotor magnetic pole is located in the large sector formed by the sectors 11 and 12; if the rotor magnetic pole is located in the large sector formed by the sectors 3 and 4 or the large sector formed by the sectors 9 and 10, calculating the slope of the voltage of the phase-a end, if the slope of the voltage of the phase-a end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the sectors 3 and 4, otherwise, the rotor magnetic pole is located in the large sector formed by the sectors 9 and 10; if the rotor magnetic pole is located in the large sector formed by the sectors 1 and 2 or the large sector formed by the sectors 7 and 8, calculating the slope of the voltage of the phase b end, if the slope of the voltage of the phase b end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the sectors 1 and 2, otherwise, the rotor magnetic pole is located in the large sector formed by the sectors 7 and 8.

With continued reference to fig. 9, in an embodiment of the present invention, the device 900 for identifying the initial position of the magnetic pole of the rotor of the electric machine further includes a voltage measuring module 910. The voltage measurement module 910 is configured to step down the terminal voltage according to a scaling factor and/or filter the terminal voltage according to a filter factor to obtain a plurality of pairs of collected voltages.

In an embodiment of the present invention, the scaling factor satisfies the following formula:

wherein, G _V Is a proportionality coefficient, R ₁ And R ₂ Are respectively the resistance values of two divider resistors, U _ADCmax To maximize the collectable voltage, U _dc For rated bus voltage, M _V For collecting voltage margin.

In an embodiment of the present invention, the filter coefficients satisfy the following formula:

R _p ＝(R ₁ R ₂ )/(R ₁ +R ₂ ) (ii) a Wherein f is _LPF Is a filter coefficient, R ₁ And R ₂ Are respectively the resistance values of two divider resistors, C ₁ Is a capacitance value.

It should be understood that the method for identifying the initial position of the magnetic pole of the motor rotor can be implemented in the device 900 for identifying the initial position of the magnetic pole of the motor rotor shown in fig. 9 or a variation thereof, but the invention is not limited thereto.

Other implementation details of the device for identifying the initial position of the magnetic pole of the motor rotor of the present embodiment may refer to the embodiments described in fig. 1 to 8, and are not further expanded herein. Those skilled in the art can make appropriate adjustments to the specific internal structure of the device 900 for identifying the initial position of a magnetic pole of a rotor of an electric machine shown in fig. 9 according to actual needs, and the invention is not limited thereto.

The embodiment of the invention provides a device for identifying the initial position of the magnetic pole of the motor rotor, which can avoid the rotation of the rotor in the judging process, effectively shorten the judging time of the initial position of the magnetic pole of the rotor and improve the judging precision.

Having thus described the basic concept, it will be apparent to those skilled in the art that the foregoing disclosure is by way of example only, and is not intended to limit the present application. Various modifications, improvements and adaptations to the present application may occur to those skilled in the art, although not explicitly described herein. Such alterations, modifications, and improvements are intended to be suggested herein and are intended to be within the spirit and scope of the exemplary embodiments of this application.

Also, this application uses specific language to describe embodiments of the application. Reference throughout this specification to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic described in connection with at least one embodiment of the present application is included in at least one embodiment of the present application. Therefore, it is emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, some features, structures, or characteristics of one or more embodiments of the present application may be combined as appropriate.

Computer program code required for the operation of various portions of the present application may be written in any one or more programming languages, including an object oriented programming language such as Java, scala, smalltalk, eiffel, JADE, emerald, C + +, C #, VB.NET, python, and the like, a conventional programming language such as C, visual Basic, fortran 2003, perl, COBOL 2002, PHP, ABAP, a dynamic programming language such as Python, ruby, and Groovy, or other programming languages, and the like. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any network format, such as a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet), or in a cloud computing environment, or as a service, such as a software as a service (SaaS).

Additionally, the order in which elements and sequences of the processes described herein are processed, the use of alphanumeric characters, or the use of other designations, is not intended to limit the order of the processes and methods described herein, unless explicitly claimed. While various presently contemplated embodiments of the invention have been discussed in the foregoing disclosure by way of example, it is to be understood that such detail is solely for that purpose and that the appended claims are not limited to the disclosed embodiments, but, on the contrary, are intended to cover all modifications and equivalent arrangements that are within the spirit and scope of the embodiments herein. For example, although the system components described above may be implemented by hardware devices, they may also be implemented by software-only solutions, such as installing the described system on an existing server or mobile device.

Similarly, it should be noted that in the preceding description of embodiments of the application, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure aiding in the understanding of one or more of the embodiments. This method of disclosure, however, is not intended to require more features than are expressly recited in the claims. Indeed, the embodiments may be characterized as having less than all of the features of a single disclosed embodiment.

Numerals describing the number of components, attributes, etc. are used in some embodiments, it being understood that such numerals used in the description of the embodiments are modified in some instances by the use of the modifier "about", "approximately" or "substantially". Unless otherwise indicated, "about", "approximately" or "substantially" indicates that the number allows a variation of ± 20%. Accordingly, in some embodiments, the numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameter should take into account the specified significant digits and employ a general digit preserving approach. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the range are approximations, in the specific examples, such numerical values are set forth as precisely as possible within the scope of the application.

Although the present invention has been described with reference to the present specific embodiments, it will be appreciated by those skilled in the art that the above embodiments are merely illustrative of the present invention and that various equivalent changes or substitutions may be made without departing from the spirit of the invention, and therefore, changes and modifications to the above embodiments within the spirit of the invention are intended to fall within the scope of the appended claims.

Claims

1. A method for identifying the initial position of a magnetic pole of a motor rotor comprises the following steps:

injecting different voltage pulses for multiple times, and collecting the terminal voltages of the suspension phases under the different voltage pulses to obtain multiple pairs of collected voltages, wherein the terminal voltages of the suspension phases are the voltages to ground of the three-phase port of the motor;

respectively calculating corresponding voltage increments of the multiple pairs of collected voltages;

comparing the magnitudes of the corresponding voltage increments of the plurality of pairs of collected voltages to determine a sector in which a rotor pole may be located, comprising the steps of:

comparing the voltage increment of the phase a terminal, the voltage increment of the phase b terminal and the voltage increment of the phase c terminal,

if the voltage increment of the phase-a end is the largest, if the voltage increment of the phase-c end is larger than that of the phase-b end, the magnetic pole of the rotor is positioned in the sector 6 or 12, otherwise, the magnetic pole of the rotor is positioned in the sector 5 or 11,

if the voltage increment of the phase b end is maximum, if the voltage increment of the phase a end is larger than the voltage increment of the phase c end, the rotor magnetic pole is positioned in the sector 4 or 10, otherwise, the rotor magnetic pole is positioned in the sector 3 or 9,

if the voltage increment of the phase c end is maximum, if the voltage increment of the phase b end is larger than the voltage increment of the phase a end, the magnetic pole of the rotor is positioned in a sector 2 or 8, otherwise, the magnetic pole of the rotor is positioned in a sector 1 or 7;

calculating the positive and negative of the slope of the terminal voltage of the suspension phase corresponding to the possibly located sector;

determining the actual sector where the rotor magnetic pole is located according to the positive and negative slopes of the terminal voltage, comprising the following steps:

if the position of the rotor magnetic pole is judged to be in the sector 6 or 12, calculating the slope of the voltage of the phase c end, if the slope of the voltage of the phase c end is judged to be positive, the rotor magnetic pole is positioned in the sector 6, otherwise the rotor magnetic pole is positioned in the sector 12,

if the position of the rotor magnetic pole is judged to be in the sector 1 or 7, calculating the slope of the voltage of the phase c end, if the slope of the voltage of the phase c end is judged to be positive, the rotor magnetic pole is positioned in the sector 1, otherwise the rotor magnetic pole is positioned in the sector 7,

if the position of the rotor magnetic pole is judged to be in the sector 2 or 8, calculating the slope of the voltage of the phase b end, if the slope of the voltage of the phase b end is judged to be positive, the rotor magnetic pole is positioned in the sector 2, otherwise the rotor magnetic pole is positioned in the sector 8,

if the magnetic pole position of the rotor is judged to be in the sector 3 or 9, calculating the slope of the voltage at the phase b end, if the slope of the voltage at the phase b end is judged to be positive, the magnetic pole of the rotor is positioned in the sector 3, otherwise, the magnetic pole of the rotor is positioned in the sector 9,

if the position of the rotor magnetic pole is judged to be in the sector 4 or 10, calculating the slope of the voltage of the phase a end, if the slope of the voltage of the phase a end is judged to be positive, the rotor magnetic pole is positioned in the sector 4, otherwise the rotor magnetic pole is positioned in the sector 10,

if the position of the rotor magnetic pole is judged to be in the sector 5 or 11, calculating the slope of the voltage of the phase a end, if the slope of the voltage of the phase a end is judged to be positive, the rotor magnetic pole is positioned in the sector 5, and if not, the rotor magnetic pole is positioned in the sector 11.

2. The method of claim 1, wherein each of the plurality of pairs of collected voltages is a collected voltage of a same suspended phase at a different injection voltage pulse.

3. The method of claim 1, wherein the trend of terminal voltage change is a slope of terminal voltage.

4. A method according to claim 3, characterized in that the step of determining the actual sector in which the rotor pole is located from the slope of the terminal voltage comprises:

and determining the actual sector where the rotor magnetic pole is positioned according to the positive and negative of the slope of the terminal voltage.

5. The method of claim 1, wherein at least six different voltage pulses are injected.

6. The method of claim 1, wherein six different voltage pulses are injected, wherein the first voltage pulse is injected in the form of a being connected to the positive bus terminal, b being connected to the negative bus terminal, and c being floating; the second voltage pulse injection mode is that b is connected with the positive end of the bus, a is connected with the negative end of the bus, and c is suspended; the third voltage pulse injection mode is that b is connected with the positive end of the bus, c is connected with the negative end of the bus, and a is suspended; the fourth voltage pulse injection mode is that c is connected with the positive end of the bus, b is connected with the negative end of the bus, and a is suspended; the fifth voltage pulse injection mode is that c is connected with the positive end of the bus, a is connected with the negative end of the bus, and b is suspended; the sixth voltage pulse injection mode is that the phase a is connected with the positive end of the bus, the phase c is connected with the negative end of the bus, and the phase b is suspended.

7. The method of claim 6, wherein the sectors comprise sector 1 to sector 12, and wherein the angle of the sector is 30 degrees.

8. The method according to claim 7, wherein the six different voltage pulses are injected, the terminal voltages of the suspended phase under the different voltage pulses are respectively collected to obtain three pairs of collected voltages, which are respectively the a-phase terminal voltage, the b-phase terminal voltage and the c-phase terminal voltage, and the a-phase terminal voltage increment, the b-phase terminal voltage increment and the c-phase terminal voltage increment are respectively calculated.

9. The method of claim 8, wherein the step of determining a sector in which the rotor pole is likely to be located comprises:

comparing the voltage increment of the phase a end, the voltage increment of the phase b end and the voltage increment of the phase c end;

if the voltage increment of the phase a end is maximum, the magnetic pole of the rotor is positioned in a large sector formed by the sectors 5 and 6 or a large sector formed by the sectors 11 and 12;

if the voltage increment of the phase b end is maximum, the rotor magnetic pole is positioned in a large sector formed by the sectors 3 and 4 or a large sector formed by the sectors 9 and 10;

if the voltage increment at the phase-c end is the largest, the rotor magnetic pole is positioned in the large sector formed by the sectors 1 and 2 or the large sector formed by the sectors 7 and 8.

10. The method of claim 9, wherein the step of calculating the terminal voltage trend of the suspension phase corresponding to the sector where the rotor magnetic pole is possibly located and determining the actual sector where the rotor magnetic pole is located according to the terminal voltage trend comprises:

if the rotor magnetic pole is located in the large sector formed by the sectors 5 and 6 or the large sector formed by the sectors 11 and 12, calculating the slope of the voltage at the phase c end, if the slope of the voltage at the phase c end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the sectors 5 and 6, otherwise, the rotor magnetic pole is located in the large sector formed by the sectors 11 and 12;

if the rotor magnetic pole is located in the large sector formed by the sectors 3 and 4 or the large sector formed by the sectors 9 and 10, calculating the slope of the voltage of the phase-a end, if the slope of the voltage of the phase-a end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the sectors 3 and 4, otherwise, the rotor magnetic pole is located in the large sector formed by the sectors 9 and 10;

if the rotor magnetic pole is located in the large sector formed by the sectors 1 and 2 or the large sector formed by the sectors 7 and 8, calculating the slope of the voltage of the phase b end, if the slope of the voltage of the phase b end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the sectors 1 and 2, otherwise, the rotor magnetic pole is located in the large sector formed by the sectors 7 and 8.

11. The method of claim 1, wherein said terminal voltages are stepped down according to a scaling factor and/or filtered according to a filtering factor to obtain said plurality of pairs of collected voltages.

12. The method of claim 1, wherein the rotor poles are positioned to within 30 degrees or 60 degrees by injecting six different voltage pulses.

13. An apparatus for identifying a magnetic pole initial position of a rotor of an electric machine, comprising:

the voltage increment comparison module is configured to acquire terminal voltages of a suspended phase under different voltage pulses according to the different voltage pulses injected for multiple times so as to obtain multiple pairs of acquired voltages, respectively calculate corresponding voltage increments of the multiple pairs of acquired voltages, and compare the corresponding voltage increments of the multiple pairs of acquired voltages so as to determine a sector where a rotor magnetic pole may be located, wherein the step of determining the sector where the rotor magnetic pole may be located according to the corresponding voltage increments of the multiple pairs of acquired voltages by the voltage increment comparison module comprises the following steps:

comparing the voltage increment of the phase a end, the voltage increment of the phase b end and the voltage increment of the phase c end,

if the voltage increment of the phase-a end is maximum, if the voltage increment of the phase-c end is larger than that of the phase-b end, the rotor magnetic pole is positioned in the sector 6 or 12, otherwise, the rotor magnetic pole is positioned in the sector 5 or 11,

if the voltage increment of the phase b end is the largest, if the voltage increment of the phase a end is larger than the voltage increment of the phase c end, the magnetic pole of the rotor is positioned in the sector 4 or 10, otherwise, the magnetic pole of the rotor is positioned in the sector 3 or 9,

if the voltage increment of the phase c is the maximum, if the voltage increment of the phase b is larger than that of the phase a, the magnetic pole of the rotor is positioned in a sector 2 or 8, otherwise, the magnetic pole of the rotor is positioned in a sector 1 or 7, wherein the terminal voltage of the suspension phase is the voltage to ground of the three-phase port of the motor; and

the magnetic pole judging module is configured to calculate the positive and negative of the slope of the terminal voltage of the suspension phase corresponding to the sector where the magnetic pole is possibly located, and determine the actual sector where the magnetic pole is located according to the positive and negative of the slope of the terminal voltage, the magnetic pole judging module calculates the terminal voltage change trend of the suspension phase corresponding to the sector where the magnetic pole is possibly located, and the step of determining the actual sector where the magnetic pole is located according to the terminal voltage change trend comprises the following steps:

if the magnetic pole position of the rotor is judged to be in the sector 6 or 12, calculating the slope of the voltage at the phase c end, if the slope of the voltage at the phase c end is judged to be positive, the magnetic pole of the rotor is positioned in the sector 6, otherwise, the magnetic pole of the rotor is positioned in the sector 12,

if the magnetic pole position of the rotor is judged to be in the sector 1 or 7, calculating the slope of the voltage of the phase c end, if the slope of the voltage of the phase c end is judged to be positive, the magnetic pole of the rotor is positioned in the sector 1, otherwise, the magnetic pole of the rotor is positioned in the sector 7,

if the magnetic pole position of the rotor is judged to be in the sector 2 or 8, calculating the slope of the voltage at the phase b end, if the slope of the voltage at the phase b end is judged to be positive, the magnetic pole of the rotor is positioned in the sector 2, otherwise, the magnetic pole of the rotor is positioned in the sector 8,

if the position of the rotor magnetic pole is judged to be in the sector 3 or 9, calculating the slope of the voltage at the phase b end, if the slope of the voltage at the phase b end is judged to be positive, the rotor magnetic pole is positioned in the sector 3, otherwise the rotor magnetic pole is positioned in the sector 9,

14. The apparatus of claim 13, wherein each of the plurality of pairs of collected voltages is a collected voltage of a same suspended phase at a different injection voltage pulse.

15. The apparatus according to claim 13, wherein said terminal voltage trend is a slope of terminal voltage.

16. The apparatus of claim 15, wherein the step of determining the actual sector in which the rotor magnetic pole is located according to the slope of the terminal voltage by the magnetic pole determination module comprises:

17. The apparatus of claim 13, wherein at least six different voltage pulses are injected.

18. The apparatus of claim 13, wherein six different voltage pulses are injected, wherein the first voltage pulse is injected in the form of a being connected to the positive terminal of the bus, b being connected to the negative terminal of the bus, and c being floating; the second voltage pulse injection mode is that b is connected with the positive end of the bus, a is connected with the negative end of the bus, and c is suspended; the third voltage pulse injection mode is that b is connected with the positive end of the bus, c is connected with the negative end of the bus, and a is suspended; the fourth time of voltage pulse injection is in a mode that c is connected with the positive end of the bus, b is connected with the negative end of the bus, and a is suspended; the fifth voltage pulse injection mode is that c is connected with the positive end of the bus, a is connected with the negative end of the bus, and b is suspended; the sixth voltage pulse injection mode is that the phase a is connected with the positive end of the bus, the phase c is connected with the negative end of the bus, and the phase b is suspended.

19. The apparatus of claim 18, wherein the sectors comprise sector 1 to sector 12, and wherein the angle of the sectors is 30 degrees.

20. The apparatus of claim 19, wherein the six different voltage pulses are injected, and the terminal voltages of the suspended phases under the different voltage pulses are respectively collected to obtain three pairs of collected voltages, which are respectively a-phase terminal voltage, b-phase terminal voltage and c-phase terminal voltage, and respectively calculate a-phase terminal voltage increment, b-phase terminal voltage increment and c-phase terminal voltage increment.

21. The apparatus of claim 19, wherein the step of the voltage delta comparison module determining the sector in which the rotor pole may be located based on the corresponding voltage delta of the plurality of pairs of collected voltages comprises:

if the voltage increment at the c-phase end is the largest, the rotor magnetic pole is positioned in the large sector formed by the sectors 1 and 2 or the large sector formed by the sectors 7 and 8.

22. The apparatus of claim 21, wherein the magnetic pole determining module calculates a terminal voltage trend of the suspension phase corresponding to the sector where the magnetic pole is likely to be located, and the step of determining the actual sector where the magnetic pole of the rotor is located according to the terminal voltage trend comprises:

if the rotor magnetic pole is located in the large sector formed by the sectors 5 and 6 or the large sector formed by the sectors 11 and 12, calculating the slope of the voltage at the c-phase end, if the slope of the voltage at the c-phase end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the sectors 5 and 6, otherwise, the rotor magnetic pole is located in the large sector formed by the sectors 11 and 12;

if the rotor magnetic pole is located in the large sector formed by the sectors 1 and 2 or the large sector formed by the sectors 7 and 8, calculating the slope of the voltage at the phase b end, if the slope of the voltage at the phase b end is judged to be positive, the rotor magnetic pole is located in the large sector formed by the sectors 1 and 2, otherwise, the rotor magnetic pole is located in the large sector formed by the sectors 7 and 8.

23. The apparatus of claim 13, further comprising:

and the voltage measurement module is configured to step down the terminal voltage according to a proportionality coefficient and/or filter the terminal voltage according to a filter coefficient so as to obtain the plurality of pairs of collected voltages.

24. The apparatus of claim 13, wherein the rotor poles are positioned to within 30 degrees or 60 degrees by injecting six different voltage pulses.