CN114598214A

CN114598214A - Motor rotor position observation method and device, rotor position observer and medium

Info

Publication number: CN114598214A
Application number: CN202210226684.1A
Authority: CN
Inventors: 王志宇; 许培林; 陈辉; 秦向南
Original assignee: Midea Welling Motor Technology Shanghai Co Ltd; Welling Wuhu Motor Manufacturing Co Ltd
Current assignee: Midea Welling Motor Technology Shanghai Co Ltd; Welling Wuhu Motor Manufacturing Co Ltd
Priority date: 2022-03-09
Filing date: 2022-03-09
Publication date: 2022-06-07
Also published as: WO2023169275A1

Abstract

The invention discloses a method and a device for observing the position of a motor rotor, a rotor position observer and a medium, wherein the method comprises the following steps: when high-frequency pulses are injected into a d axis of the motor, a reference value is determined, and six comparison values of three paths of modulation corresponding to output required voltage vectors under single resistance sampling are determined; determining a difference between the reference value and the comparison value Act21 or Act 22; adjusting six comparison values according to the difference value, and adjusting the six comparison values according to the adjusted comparison value Act21_NewOr Act22_NewDetermining a first current sampling trigger value and a second current sampling trigger value; according to adjustedThe six comparison values control the motor, and current sampling is carried out on the motor according to the first current sampling trigger value and the second current sampling trigger value to obtain a first sampling current and a second sampling current; and estimating the rotor position of the motor according to the first sampling current and the second sampling current. Therefore, the sampling current precision of single-resistor sampling can be effectively improved, and the motor rotor position observation precision is further improved.

Description

Motor rotor position observation method and device, rotor position observer and medium

Technical Field

The invention relates to the technical field of motor control, in particular to a motor rotor position observation method, a motor rotor position observation device, a rotor position observer and a medium.

Background

The motor position sensorless control method based on high-frequency injection is simple to implement, low in cost and good in control performance in a low-speed area, and can achieve low-speed load starting of the motor. The method comprises the steps of injecting periodic positive and negative pulses into a d axis, sampling q-axis high-frequency current response caused by the pulses, and sending the high-frequency current response to a phase-locked loop to solve to obtain the estimated position of the motor. The traditional observer method has better performance in a medium-high speed region, but cannot be converged in a low-speed region, so that the high-frequency injection method has high practical application value.

The single-resistor sampling technology is characterized in that a sampling resistor on a direct-current negative bus is used for sampling current, sampling is needed twice in one control period, sampling is respectively carried out in the action time of two effective voltage vectors (namely non-zero voltage vectors), and the phase sequence of the sampled current is judged according to the voltage vector condition after sampling is finished.

During single-resistor sampling, two current sampling needs a certain time, generally before and after the action time of the 2 nd or 5 th switching tube is selected, namely sampling is carried out in the action time of two effective voltage vectors, if a synthesized voltage vector is positioned near a sector switching boundary, at least one effective voltage vector is too small, so that in order to meet the requirement of sampling time, phase shifting processing needs to be carried out on the action time of the switching tube, and the accuracy of two current sampling is ensured. However, the sampling time of such single-resistor sampling varies, and particularly, when the sampling time is near different sector switching regions, the difference of the phase shifting manner causes a large difference in the sampling time. When the motor runs at a low speed, the back electromotive force and the resistance voltage drop are small, the output voltage of the controller is mainly high-frequency injection voltage, the high-frequency injection voltage is positive-negative periodic injection, the phase difference of corresponding sectors is 180 degrees, so that a large sampling time error is introduced due to phase shift, a large error exists in q-axis high-frequency current response obtained by sampling, a large error also exists in an estimated position obtained by solving, and the control performance of a system is influenced.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, a first object of the present invention is to provide a method for observing a position of a motor rotor, which can effectively improve the accuracy of sampling current sampled by a single resistor, and further improve the accuracy of observing the position of the motor rotor.

A second object of the invention is to propose a computer-readable storage medium.

A third object of the invention is to propose a rotor position observer.

A fourth object of the present invention is to provide a motor rotor position observation device.

In order to achieve the above object, an embodiment of a first aspect of the present invention provides a method for observing a rotor position of an electric machine, including: when high-frequency pulses are injected into a d shaft of the motor, determining a reference value, and determining six comparison values Act11, Act21, Act31, Act32, Act22 and Act12 of three paths of modulation corresponding to output required voltage vectors under single-resistor sampling; determining a difference between the reference value and the comparison value Act21 or Act 22; adjusting six comparison values Act11, Act21, Act31, Act32, Act22 and Act12 according to the difference values, and adjusting the six comparison values according to the adjusted comparison values Act21_NewOr Act22_NewDetermining a first current sampling trigger value and a second current sampling trigger value; according to the adjusted six comparison values Act11_New、Act21_New、Act31_New、Act32_New、Act22_New、Act12_NewControlling the motor according toThe method comprises the steps that a first current sampling trigger value and a second current sampling trigger value sample current of a motor to obtain a first sampling current and a second sampling current; and estimating the rotor position of the motor according to the first sampling current and the second sampling current.

According to the motor rotor position observation method provided by the embodiment of the invention, six comparison values of three modulation paths corresponding to output required voltage vectors under single resistance sampling are adjusted according to the difference value between the reference value and the comparison values, the first current sampling trigger value and the second current sampling trigger value are determined according to the adjusted comparison values, the motor is controlled according to the adjusted six comparison values, the current sampling is carried out on the motor according to the first current sampling trigger value and the second current sampling trigger value, the first sampling current and the second sampling current are obtained, and the rotor position of the motor is estimated according to the first sampling current and the second sampling current, so that the sampling current precision of single resistance sampling can be effectively improved, and the motor rotor position observation precision is further improved.

According to one embodiment of the invention, determining the reference value comprises: acquiring a triangular wave carrier peak count value; and determining a reference value according to the peak count value of the triangular wave carrier.

According to one embodiment of the present invention, the reference value is equal to or greater than the difference between the comparison value Act22 and the comparison value Act 11.

According to one embodiment of the present invention, the reference value is 0.5 times the triangular carrier peak count value.

According to one embodiment of the invention, the six comparison values Act11, Act21, Act31, Act32, Act22, Act12 are adjusted according to the following formula:

Act11_New＝Act11+DetaN；

Act21_New＝Nref；

Act31_New＝Act31+DetaN；

Act32_New＝Act32-DetaN；

Act22_New＝Nref；

Act12_New＝Act12-DetaN；

where DetaN is the difference and Nref is the reference value.

According to one embodiment of the invention, when single-resistance sampling is performed in the rising phase of a triangular wave carrier, a first current sampling trigger value and a second current sampling trigger value are determined according to the following formulas:

Trig1_New＝Act21_New-Tsample；

Trig2_New＝Act21_New+Tdead+Tup；

wherein, the Trig1_NewFor the first current sample trigger value, Trig2_NewFor the second current sampling trigger value, Tsample is the time required by hardware sampling, Tdead is the dead time, and Tup is the time for the current to rise to a stable value.

According to one embodiment of the invention, when single resistance sampling is performed in a falling phase of a triangular wave carrier, a first current sampling trigger value and a second current sampling trigger value are determined according to the following formulas:

Trig1_New＝Act22_New+Tsample；

Trig2_New＝Act22_New-Tdead-Tup；

In order to achieve the above object, a second aspect of the present invention provides a computer-readable storage medium, on which a motor rotor position observation program is stored, and the motor rotor position observation program, when executed by a processor, implements the aforementioned motor rotor position observation method.

According to the computer-readable storage medium provided by the embodiment of the invention, based on the motor rotor position observation method, the sampling current precision of single-resistor sampling can be effectively improved, and the motor rotor position observation precision is further improved.

In order to achieve the above object, a third aspect of the present invention provides a rotor position observer, which includes a memory, a processor, and a motor rotor position observing program stored in the memory and operable on the processor, wherein the processor implements the aforementioned motor rotor position observing method when executing the motor rotor position observing program.

According to the rotor position observer provided by the embodiment of the invention, based on the motor rotor position observation method, the sampling current precision of single-resistor sampling can be effectively improved, and the motor rotor position observation precision is further improved.

In order to achieve the above object, a fourth aspect of the present invention provides an apparatus for observing a rotor position of an electric machine, including: a first determination module for determining a reference value; the second determination module is used for determining six comparison values Act11, Act21, Act31, Act32, Act22 and Act12 of three-way modulation corresponding to the voltage vector required by the single-resistor sampling output; the adjusting module is used for determining the difference between the reference value and the comparison value Act21 or Act22 when injecting the high-frequency pulse to the d shaft of the motor, and adjusting the six comparison values Act11, Act21, Act31, Act32, Act22 and Act12 according to the difference; a third determining module for determining the comparison value Act21 according to the adjusted comparison value_NewOr Act22_NewDetermining a first current sampling trigger value and a second current sampling trigger value; a control module for adjusting the six comparison values Act11_New、Act21_New、Act31_New、Act32_New、Act22_New、Act12_NewThe method comprises the steps of controlling a motor, sampling current of the motor according to a first current sampling trigger value and a second current sampling trigger value, obtaining a first sampling current and a second sampling current, and estimating the position of a rotor of the motor according to the first sampling current and the second sampling current.

According to the motor rotor position observation device provided by the embodiment of the invention, six comparison values of three modulation corresponding to output required voltage vectors under single resistance sampling are adjusted according to the difference value between the reference value and the comparison values, the first current sampling trigger value and the second current sampling trigger value are determined according to the adjusted comparison values, the motor is controlled according to the adjusted six comparison values, the current sampling is carried out on the motor according to the first current sampling trigger value and the second current sampling trigger value, the first sampling current and the second sampling current are obtained, and the rotor position of the motor is estimated according to the first sampling current and the second sampling current, so that the sampling current precision of single resistance sampling can be effectively improved, and further the motor rotor position observation precision is improved.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

FIG. 1 is a diagram of a motor control system according to one embodiment of the present invention;

FIG. 2 is a diagram of a single resistor high frequency injection control system;

FIG. 3a is a schematic diagram of the voltage vector of the injected positive voltage pulse and the operation of the switch tube at the 0 position according to one embodiment of the present invention;

FIG. 3b is a schematic diagram of the voltage vectors and switching tube operation for injecting negative voltage pulses at the 0 ° position according to one embodiment of the present invention;

FIG. 4 is a schematic flow chart of a method for observing a position of a rotor of an electric machine according to one embodiment of the present invention;

FIG. 5 is a schematic diagram of the switching tube after adjustment corresponding to FIGS. 3a and 3 b;

fig. 6 is a schematic structural diagram of a motor rotor position observation device according to an embodiment of the invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the motor position sensorless vector control process, in order to obtain the motor rotor position, periodic positive and negative voltage pulses can be injected into a d axis, q-axis high-frequency current response caused by the pulses is sampled, and the high-frequency current response is sent to a phase-locked loop to be solved to obtain the motor rotor position. Based on cost consideration, a single-resistor sampling technology is generally adopted to sample high-frequency current response, the single-resistor sampling technology is to sample current by using a sampling resistor on a direct-current negative bus, as shown in fig. 1, the current is sampled by using a sampling resistor R on the direct-current negative bus, during sampling, sampling is required twice in a control period, sampling is respectively performed within action time of two effective voltage vectors (namely non-zero voltage vectors), and after sampling is finished, a phase sequence of the sampled current is judged according to the condition of the voltage vectors, so that two-phase current is obtained.

During single-resistor sampling, two times of current sampling both need a certain time, generally, the 2 nd or 5 th switching tube action time is selected before and after, namely sampling is carried out in the action time of two effective voltage vectors, if a synthesized voltage vector is positioned near a sector switching boundary, at least one effective voltage vector is too small, so that in order to meet the requirement of sampling time, phase shift processing needs to be carried out on the switching tube action time, and the accuracy of two times of current sampling is ensured. However, the sampling time of such single-resistor sampling varies, and particularly, when the sampling time is near different sector switching regions, the difference of the phase shifting manner causes a large difference in the sampling time. Because the back electromotive force and the resistance voltage drop are small when the motor runs at low speed, as shown in fig. 2, the output voltage of the controller is mainly high-frequency injection voltage, the high-frequency injection voltage is positive and negative periodic injection, and the difference between corresponding sectors is 180 degrees, so that a large sampling time error is introduced due to phase shift, a large error exists in q-axis high-frequency current response obtained by sampling, a large error also exists in an estimated position obtained by solving, and the control performance of a control system is influenced.

Specifically, the motor is described as being in the 0 ° position. In the conventional method, when estimating the rotor position, a positive voltage pulse is injected first, as shown in fig. 3a, the output resultant voltage vector Uinj is substantially coincident with U4(100), the action time t1 of the first effective voltage vector is large, and the action time t2 of the second effective voltage vector is small, so that a phase shift is required, and the current sampling time determined based on the phase shift is close to the middle of the triangular wave carrier period, such as the Trig1 and the Trig2 in fig. 3a, which are close to the middle of the triangular wave carrier period; after the positive voltage pulse is finished, injecting a negative voltage pulse, as shown in fig. 3b, where the output composite voltage vector-Uinj approximately differs from the composite voltage vector Uinj when the positive voltage pulse is injected by 180 °, and is substantially coincident with U3(011), the action time t1 of the first effective voltage vector is small, the action time t2 of the second effective voltage vector is large, and the phase shift is also required, but the current sampling time determined based on the phase shift is close to the end of the triangular wave carrier period, such as Trig1 and Trig2 in fig. 3b close to the end of the triangular wave carrier period. Therefore, the current sampling time when the positive voltage pulse is injected is different from the current sampling time when the negative voltage pulse is injected, so that a large error exists in the response of the sampled high-frequency current, and further a large error exists in the estimated position.

Based on this, can select the benchmark according to triangle wave carrier cycle count value earlier in this application, because the current sampling moment is based on 2 nd or 5 th switch tube action moment calculation and obtains, consequently through aligning 2 nd or 5 th switch tube action moment with the benchmark, can guarantee after shifting the phase that the current sampling moment when positive and negative voltage pulse injects is the same to reduce the current sampling error because of the different introduction of current sampling moment, and then improve the estimation accuracy of motor rotor position.

Fig. 4 is a schematic flow chart of a method for observing the position of a rotor of an electric machine according to an embodiment of the present invention. Referring to fig. 4, the method for observing the position of the rotor of the motor may include the steps of:

and step S101, when high-frequency pulses are injected into the d axis of the motor, determining a reference value, and determining six comparison values Act11, Act21, Act31, Act32, Act22 and Act12 of three-way modulation corresponding to the output required voltage vector under single resistance sampling.

Specifically, when high-frequency pulses, i.e. high-frequency positive and negative voltage pulses are injected into the d-axis of the motor, reference values required for reducing current sampling errors introduced due to different current sampling timings can be obtained, and the comparison values Act11, Act21, Act31, Act32, Act22 and Act12 of each PWM (Pulse Width Modulation) signal required by the control motor are obtained according to the single resistance sampling calculation, here, Act11 represents a triangular wave carrier count value corresponding to the 1 st switching tube operation time in the three-phase inverter bridge, Act21 represents a triangular wave carrier count value corresponding to the 2 nd switching tube operation time, Act31 represents a triangular wave carrier count value corresponding to the 3 rd switching tube operation time, Act32 represents a triangular wave carrier count value corresponding to the 4 th switching tube operation time, Act22 represents a triangular wave carrier count value corresponding to the 5 th switching tube operation time, and Act12 represents a triangular wave carrier count value corresponding to the 6 th switching tube operation time. In the application, the triangular wave carrier counting mode is an increasing mode and a decreasing mode, and Act11 is more than Act21 is more than Act31, and Act32 is more than Act22 is more than Act12 correspondingly.

For example, as shown in fig. 3 a-3 b, PWM1, PWM2 and PWM3 are PWM control signals of the upper arm switching tubes VT1, VT3 and VT5 shown in fig. 1, respectively (the PWM control signals of the lower arm switching tubes VT4, VT6 and VT2 are 180 ° different from the PWM control signals of the upper arm switching tubes VT1, VT3 and VT 5). When positive and negative voltage pulses are injected, when a voltage vector is in a sector I, comparison values corresponding to PWM1 are Act11 and Act12, comparison values corresponding to PWM2 are Act21 and Act22, comparison values corresponding to PWM3 are Act31 and Act32, namely the duty ratio of PWM1 is the maximum value, the duty ratio of PWM2 is the intermediate value, and the duty ratio of PWW3 is the minimum value; when the voltage vector is in the sector II, the comparison values corresponding to the PWM1 are Act21 and Act22, the comparison values corresponding to the PWM2 are Act11 and Act12, the comparison values corresponding to the PWM3 are Act31 and Act32, that is, the duty ratio of the PWM1 is a middle value, the duty ratio of the PWM2 is a maximum value, and the duty ratio of the PWW3 is a minimum value; when the voltage vector is in the sector III, the comparison values corresponding to the PWM1 are Act31 and Act32, the comparison values corresponding to the PWM2 are Act11 and Act12, the comparison values corresponding to the PWM3 are Act21 and Act22, that is, the duty ratio of the PWM1 is the minimum value, the duty ratio of the PWM2 is the maximum value, and the duty ratio of the PWW3 is the intermediate value; when the voltage vector is in the sector IV, the comparison values corresponding to the PWM1 are Act31 and Act32, the comparison values corresponding to the PWM2 are Act21 and Act22, the comparison values corresponding to the PWM3 are Act11 and Act12, that is, the duty ratio of the PWM1 is the minimum value, the duty ratio of the PWM2 is the intermediate value, and the duty ratio of the PWW3 is the maximum value; when the voltage vector is in the sector V, the comparison values corresponding to the PWM1 are Act21 and Act22, the comparison values corresponding to the PWM2 are Act31 and Act32, the comparison values corresponding to the PWM3 are Act11 and Act12, that is, the duty ratio of the PWM1 is a middle value, the duty ratio of the PWM2 is a minimum value, and the duty ratio of the PWW3 is a maximum value; when the voltage vector is in the sector VI, the comparison values corresponding to the PWM1 are Act11 and Act12, the comparison values corresponding to the PWM2 are Act31 and Act32, and the comparison values corresponding to the PWM3 are Act21 and Act22, that is, the duty ratio of the PWM1 is the maximum value, the duty ratio of the PWM2 is the minimum value, and the duty ratio of the PWW3 is the intermediate value.

It should be noted that, when determining the comparison value of each path of PWM signal, the phase shift processing is also performed on the determined comparison value, so as to ensure that single resistance sampling is performed within the effective voltage vector action time, and ensure the validity and accuracy of current sampling. When the phase shifting processing is carried out, the corresponding comparison values are adjusted according to the current sampling stage, the t1/2 and the t2/2, so that the smaller value of the t1/2 and the t2/2 is larger than the minimum sampling time. For example, as shown in fig. 3a, when current sampling is performed in the period falling phase of the triangular wave carrier, t2/2 is smaller, and at this time, the high level of PWM3 is shifted left, the corresponding comparison value Act31 is decreased, and the comparison value Act32 is increased; when current sampling is performed in the rising phase of the triangular wave carrier period, t2/2 is small, and at this time, the high level of PWM3 is shifted to the right, and the comparison value Act31 is increased and the comparison value Act32 is decreased. As shown in fig. 3b, when the current sampling is performed in the period falling phase of the triangular wave carrier, t1/2 is smaller, at this time, the high level of PWM1 is shifted to the right, the corresponding comparison value Act11 is increased, and the comparison value Act12 is decreased; when current sampling is performed in the rising phase of the triangular wave carrier period, t1/2 is small, and at this time, the high level of PWM1 is shifted to the left, and the comparison value Act11 is decreased and the comparison value Act12 is increased.

When the reference value is obtained, the current sampling time is calculated based on the 2 nd or 5 th switching tube operation time, so that the 2 nd or 5 th switching tube operation time is ensured to be consistent, that is, the current sampling time is ensured to be consistent, as shown in fig. 3 a-3 b, the 5 th switching tube operation time is the time corresponding to the comparison value Act22, and the current sampling time corresponding to the Trig1 and the Trig2 is calculated based on the comparison value Act22, so that the time corresponding to the comparison value Act22 in fig. 3a and the time corresponding to the comparison value Act22 in fig. 3b are ensured to be consistent, that is, the current sampling time in fig. 3a and the current sampling time in fig. 3b are ensured to be consistent. Considering that the counted value of the triangular wave carrier period when the positive voltage pulse is injected is the same as the counted value of the triangular wave carrier period when the negative voltage pulse is injected, a reference value can be selected based on the counted value of the triangular wave carrier period, and the action time of the 2 nd or 5 th switching tube is aligned with the reference value, so that the current sampling time when the positive and negative voltage pulses are injected after phase shifting is the same, for example, the time corresponding to the comparison value Act22 in fig. 3a and the time corresponding to the comparison value Act22 in fig. 3b are both aligned with the reference value, so that the current sampling time in fig. 3a is consistent with the current sampling time in fig. 3b, and thus, the current sampling error caused by the difference of the current sampling time due to phase shifting is reduced.

In some embodiments of the invention, determining the reference value may comprise: acquiring a triangular wave carrier peak count value; and determining a reference value according to the peak count value of the triangular wave carrier.

Specifically, when injecting the high-frequency pulse into the d-axis of the motor, a positive voltage pulse may be injected first, and at this time, the triangular wave carrier vertex count value N corresponding to the positive voltage pulse is determined first_1/2PeriodAnd counting the value N according to the peak of the triangular wave carrier_1/2PeriodThe reference value Nref is acquired. After the positive voltage pulse ends, the negative voltage pulse is injected, and the negative voltage pulse is a voltage pulse having a direction opposite to that of the positive voltage pulse, so that the reference value Nref determined when the positive voltage pulse is injected can be directly used as the reference value Nref determined when the negative voltage pulse is injected, or can be directly calculated.

In determining the reference value Nref, the peak count value N of the triangular carrier wave may be specifically determined_1/2PeriodAnd the amplitude of the injected positive and negative voltage pulses. For example, since the amplitude of the selected positive and negative voltage pulses is generally not more than 50% of the dc bus voltage Udc when the rotor position of the motor is estimated based on the hf injection method, the reference value Nref may be 0.5 times the peak count value of the triangular carrier, i.e., the reference value Nref is (1/2) × N_1/2Period. The reference value Nref is equal to or greater than the difference between the comparison value Act22 and the comparison value Act 11.

In step S102, the difference between the reference value and the comparison value Act21 or Act22 is determined.

Specifically, when current sampling is performed in the triangular wave carrier rising phase, the corresponding comparison value is Act21, and the difference value DetaN between the reference value and the comparison value Act21 is Nref-Act 21; when current sampling is performed in the triangular wave carrier falling phase, the corresponding comparison value is Act22, and the difference DetaN between the reference value Nref and the comparison value Act22 is Nref-Act 22. It can be understood that, when the triangular wave carrier count mode is first increasing and then decreasing, and the phase shift processing is not performed on the comparison values Act21 and Act22 during phase shift, the two calculated differences DetaN are equal and may not be distinguished in subsequent use, while in other cases, the two calculated differences DetaN may not be equal and need to be distinguished in subsequent use.

Step S103, adjusting the six comparison values Act11, Act21, Act31, Act32, Act22 and Act12 according to the difference values, and adjusting the six comparison values according to the adjusted comparison values Act21_NewOr Act22_NewA first current sampling trigger value and a second current sampling trigger value are determined.

Specifically, after obtaining the difference DetaN, the six comparison values may be adjusted based on the difference DetaN, where the adjustment principle is that, if t2 is a smaller value, the zero voltage vector U7(111) is compensated by the zero voltage vector U0(000), that is, the duty ratios of PWM1, PWM2, and PWM3 are increased, that is, the high level times of PWM1, PWM2, and PWM3 are increased; if t1 is a smaller value, the zero voltage vector U0(000) is compensated by the zero voltage vector U7(111), i.e., the duty ratios of PWM1, PWM2 and PWM3 are reduced, i.e., the high-level time of PWM1, PWM2 and PWM3 is reduced.

For example, as shown in fig. 3a, when t2 is smaller, the zero voltage vector U7(111) is compensated by the zero voltage vector U0(000), and the adjusted PWM1, PWM2 and PWM3 are increased (i.e., expanded) in high level relative to the PWM signal before adjustment as shown in fig. 5 (a); as shown in fig. 3b, when t1 is smaller, the zero voltage vector U0(000) is compensated by the zero voltage vector U7(111), and as shown in fig. 5 b, the high level of the adjusted PWM signal is reduced (i.e., retracted) relative to the PWM signal before adjustment in the adjusted PWM1, PWM2 and PWM 3.

It should be noted that the purpose of setting the reference value Nref to be equal to or greater than the difference between the comparison value Act22 and the comparison value Act11 is to ensure that the zero voltage vector U0(000) sufficiently supplements the zero voltage vector U7(111) when t2 is smaller, to avoid that the zero voltage vector U7(111) is insufficiently supplemented due to too short duration of the zero voltage vector U0(000), and that the zero voltage vector U7(111) sufficiently supplements the zero voltage vector U0(000) when t1 is smaller, to avoid that the zero voltage vector U0(000) is insufficiently supplemented due to too short duration of the zero voltage vector U7(111), so as to ensure normal control of the motor.

Specifically, when the six comparison values are adjusted according to the difference DetaN, the six comparison values Act11, Act21, Act31, Act32, Act22, Act12 can be specifically adjusted by the following formula (1):

note that, since the difference DetaN has a positive/negative division, the formula (1) is applied to the foregoing two cases. For example, the difference DetaN is Nref-Act22, and if t2 is a smaller value, the difference DetaN < 0, and at this time, the six adjusted comparison values determined based on equation (1) match those shown in fig. 5 (a); if t1 is smaller, the difference DeTaN is greater than 0, and the adjusted six comparison values determined based on equation (1) correspond to those shown in FIG. 5 (b).

After obtaining the adjusted six comparison values, it is based on the adjusted comparison value Act21_NewOr Act22_NewA first current sampling trigger value and a second current sampling trigger value are determined. Specifically, in one control cycle, the current sampling may be performed before or after the 2 nd or 5 th switching tube actuation time, that is, at the comparison value Act21_NewOr Act22_NewThe current is sampled before and after the corresponding time, and therefore the comparison value Act21 is obtained_NewAnd Act22_NewThereafter, a first current sample trigger value Trig1 and a second current sample trigger value Trig2 may be obtained from one of the two comparison values. For example, if the drop of the triangular carrier wave is selectedIf single-resistor sampling is carried out in the stage, the comparison value Act22 is used_NewAcquiring a first current sampling trigger value Trig1 and a second current sampling trigger value Trig 2; if the rising stage of the triangular wave carrier wave is selected for single-resistor sampling, the comparison value Act21 is used_NewA first current sample trigger value Trig1 and a second current sample trigger value Trig2 are obtained.

The comparison value Act21 is used_NewOr Act22_NewWhen the first current sampling trigger value Trig1 and the second current sampling trigger value Trig2 are obtained, the determination can be performed according to the time required by hardware sampling (such as the sampling time of an ADC converter), dead time (that is, the time reserved for preventing the upper and lower switching tubes of the same bridge arm from being simultaneously turned on when a PWM signal is output, for example, after the upper bridge arm switching tube is turned off and the dead time is delayed, the lower bridge arm switching tube can be turned on, or after the lower bridge arm switching tube is turned off and the dead time is delayed, the upper bridge arm switching tube can be turned on), and the current stabilization time after the switching tubes are turned off (for example, after the switching tubes are turned on, the current gradually rises until the switching tubes are in a stable state), so as to ensure sufficient current sampling time, avoid the dead time and the current non-stabilization time, and ensure the effectiveness and accuracy of current sampling.

According to one embodiment of the present invention, when single resistance sampling is performed in a rising phase of a triangular wave carrier, a first current sampling trigger value and a second current sampling trigger value are determined according to the following formula (2):

According to one embodiment of the present invention, when single resistance sampling is performed in a falling phase of a triangular wave carrier, a first current sampling trigger value and a second current sampling trigger value are determined according to the following formula (3):

wherein, the Trig1_NewFor the first current sample trigger value, Trig2_NewFor the second current sampling trigger value, Tsample is the time required for hardware sampling, Tdead is the dead time, and Tup is the time for the current to rise to a stable value.

That is to say, the first current sampling is performed before the 2 nd or 5 th switching tube action time, and the second current sampling is performed after the first current sampling, and considering that the two sampling times are as close as possible to reduce the sampling time error, a hardware sampling required time Tsample is reserved for the first current sampling, and a dead time Tdead and a time Tup for the current to rise to a stable time are reserved for the second current sampling.

Step S104, according to the adjusted six comparison values Act11_New、Act21_New、Act31_New、Act32_New、Act22_New、Act12_NewAnd controlling the motor, and sampling the current of the motor according to the first current sampling trigger value and the second current sampling trigger value to obtain a first sampling current and a second sampling current.

Specifically, after the six adjusted comparison values are obtained, the motor is controlled according to the six adjusted comparison values, and in the control process, current sampling is performed according to the first current sampling trigger value Trig1 and the second current sampling trigger value Trig2, so that a first sampling current and a second sampling current are obtained.

Taking the single resistance sampling at the falling stage of the triangular wave carrier as an example. As shown in fig. 5(a) -5 (b), after the adjusted six comparison values are obtained, if a triangular wave carrier is generated by the timer count value, the timer count value is equal to the comparison value Act11_NewWhen the bridge is in use, the upper bridge arm switching tube VT1 in the bridge of FIG. 1 is controlled to be conducted, the lower bridge arm switching tubes VT6 and VT2 are kept conducted, and the other switching tubes are all turned off; when the timer count value equals the comparison value Act21_NewControl upper arm opening in fig. 1The switch tube VT3 is conducted, the upper bridge arm switch tube VT1 and the lower bridge arm switch tube VT2 are kept conducted, and the other switch tubes are all turned off; when the timer count value equals the comparison value Act31_NewWhen the bridge rectifier is in use, the upper bridge arm switching tube VT5 in the bridge rectifier 1 is controlled to be conducted, the upper bridge arm switching tubes VT1 and VT3 are kept to be conducted, and the other switching tubes are all turned off; when the timer count value equals the comparison value Act32_NewWhen the bridge is in use, the lower bridge arm switching tube VT2 in the bridge of FIG. 1 is controlled to be conducted, the upper bridge arm switching tubes VT1 and VT3 are kept conducted, and the other switching tubes are all turned off; when the count value of the timer is equal to the first current sampling trigger value Trig1, performing current sampling through the sampling resistor R in fig. 1 to obtain a first sampling current; when the timer count value equals the comparison value Act22_NewWhen the bridge is in use, the lower bridge arm switching tube VT6 in the bridge of FIG. 1 is controlled to be conducted, the upper bridge arm switching tube VT1 and the lower bridge arm switching tube VT2 are kept conducted, and the other switching tubes are all turned off; when the count value of the timer is equal to the second current sampling trigger value Trig2, performing current sampling through the sampling resistor R in fig. 1 to obtain a second sampling current; when the timer count value equals the comparison value Act12_NewAnd when the voltage is higher than the threshold voltage, the lower bridge arm switching tube VT4 in the control diagram 1 is switched on, the lower bridge arm switching tubes VT2 and VT6 are kept switched on, and the other switching tubes are switched off.

Therefore, based on the comparison value and the sampling trigger value, the control of the motor can be realized, and current sampling is carried out in the control process. The process of performing single-resistance sampling at the rising phase of the triangular carrier is the same as the process of performing single-resistance sampling at the falling phase of the triangular carrier, and detailed description thereof is omitted.

And step S105, estimating the rotor position of the motor according to the first sampling current and the second sampling current.

Specifically, position observation can be performed according to the first sampling current and the second sampling current to obtain the rotor position of the motor, which can be specifically realized by adopting the prior art and will not be described herein.

According to the motor rotor position observation method provided by the embodiment of the invention, six comparison values of three-way modulation corresponding to the output required voltage vector under single resistance sampling are adjusted according to the difference value between the reference value and the comparison value, and determining a first current sampling trigger value and a second current sampling trigger value according to the adjusted comparison value, and controlling the motor according to the adjusted six comparison values, sampling the current of the motor according to the first current sampling trigger value and the second current sampling trigger value to obtain a first sampling current and a second sampling current, and estimating the rotor position of the motor according to the first sampling current and the second sampling current, which can effectively improve the sampling current precision of single resistance sampling, and the motor rotor position observation precision is further improved, the algorithm is simple, and the engineering application is easy, so that the excellent control performance is kept under the advantage of low cost.

In an embodiment of the present invention, there is also provided a computer-readable storage medium having stored thereon a motor rotor position observation program which, when executed by a processor, implements the aforementioned motor rotor position observation method.

In an embodiment of the present invention, a rotor position observer is further provided, which includes a memory, a processor, and a motor rotor position observation program stored in the memory and operable on the processor, and when the processor executes the motor rotor position observation program, the aforementioned motor rotor position observation method is implemented.

Fig. 6 is a schematic view of a rotor position observing apparatus of an electric machine according to an embodiment of the present invention, and referring to fig. 6, the rotor position observing apparatus of an electric machine may include: the device comprises a first determination module 10, a second determination module 20, an adjustment module 30, a third determination module 40 and a control module 50.

The first determination module 10 is configured to determine a reference value; the second determination module 20 is used for determining the single resistanceSampling six comparison values Act11, Act21, Act31, Act32, Act22 and Act12 of three-way modulation corresponding to the lower output required voltage vector; the adjusting module 30 is used for determining the difference between the reference value and the comparison value Act21 or Act22 when injecting the high-frequency pulse to the d shaft of the motor, and adjusting six comparison values Act11, Act21, Act31, Act32, Act22 and Act12 according to the difference; the third determining module 40 is used for determining the comparison value Act21 according to the adjusted comparison value_NewOr Act22_NewDetermining a first current sampling trigger value and a second current sampling trigger value; the control module 50 is used for adjusting six comparison values Act11 according to the adjusted six comparison values_New、Act21_New、Act31_New、Act32_New、Act22_New、Act12_NewThe method comprises the steps of controlling a motor, sampling current of the motor according to a first current sampling trigger value and a second current sampling trigger value, obtaining a first sampling current and a second sampling current, and estimating the position of a rotor of the motor according to the first sampling current and the second sampling current.

According to an embodiment of the present invention, the first determining module 10 is specifically configured to: acquiring a triangular wave carrier peak count value; and determining a reference value according to the peak count value of the triangular wave carrier.

According to an embodiment of the present invention, the adjusting module 30 is specifically configured to adjust the six comparison values Act11, Act21, Act31, Act32, Act22, Act12 according to the following formula:

Act11_New＝Act11+DetaN；

Act21_New＝Nref；

Act31_New＝Act31+DetaN；

Act32_New＝Act32-DetaN；

Act22_New＝Nref；

Act12_New＝Act12-DetaN；

where DetaN is the difference and Nref is the reference value.

According to an embodiment of the present invention, the third determining module 40 is specifically configured to determine the first current sampling trigger value and the second current sampling trigger value according to the following formulas when performing single-resistor sampling at the rising stage of the triangular carrier wave:

Trig1_New＝Act21_New-Tsample；

Trig2_New＝Act21_New+Tdead+Tup；

According to an embodiment of the present invention, the third determining module 40 is specifically configured to determine the first current sampling trigger value and the second current sampling trigger value according to the following formulas when performing single resistance sampling at a falling stage of the triangular carrier wave:

Trig1_New＝Act22_New+Tsample；

Trig2_New＝Act22_New-Tdead-Tup；

It should be noted that, for the description of the device for observing the position of the motor rotor in the present application, please refer to the description of the method for observing the position of the motor rotor in the present application, and details are not repeated herein.

According to the motor rotor position observation device provided by the embodiment of the invention, six comparison values of three modulation paths corresponding to the output required voltage vector under single resistance sampling are adjusted according to the difference value between the reference value and the comparison values, the first current sampling trigger value and the second current sampling trigger value are determined according to the adjusted comparison values, the motor is controlled according to the adjusted six comparison values, the current sampling is carried out on the motor according to the first current sampling trigger value and the second current sampling trigger value, the first sampling current and the second sampling current are obtained, and the rotor position of the motor is estimated according to the first sampling current and the second sampling current, so that the sampling current precision of single resistance sampling can be effectively improved, and the motor rotor position observation precision is further improved.

It should be noted that the logic and/or steps represented in the flowcharts or otherwise described herein, such as an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.

It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and that changes, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A method for observing the position of a rotor of an electric motor, comprising:

when high-frequency pulses are injected into a d axis of the motor, a reference value is determined, and six comparison values Act11, Act21, Act31, Act32, Act22 and Act12 of three-way modulation corresponding to the output required voltage vector under single resistance sampling are determined;

determining a difference between the reference value and a comparison value Act21 or Act 22;

adjusting six comparison values Act11, Act21, Act31, Act32, Act22 and Act12 according to the difference values, and adjusting the six comparison values according to the adjusted comparison values Act21_NewOr Act22_NewDetermining a first current sampling trigger value and a second current sampling trigger value;

according to the adjusted six comparison values Act11_New、Act21_New、Act31_New、Act32_New、Act22_New、Act12_NewControlling a motor, and sampling the current of the motor according to the first current sampling trigger value and the second current sampling trigger value to obtain a first sampling current and a second sampling current;

and estimating the rotor position of the motor according to the first sampling current and the second sampling current.

2. The method of claim 1, wherein determining a reference value comprises:

acquiring a triangular wave carrier peak count value;

and determining the reference value according to the triangular wave carrier peak count value.

3. The method according to claim 2, wherein the reference value is equal to or greater than the difference between the comparison value Act22 and the comparison value Act 11.

4. The method according to claim 2, wherein the reference value is 0.5 times the triangular carrier vertex count value.

5. Method according to any of claims 1-4, characterized in that the six comparison values Act11, Act21, Act31, Act32, Act22, Act12 are adjusted according to the following formula:

Act11_New＝Act11+DetaN；

Act21_New＝Nref；

Act31_New＝Act31+DetaN；

Act32_New＝Act32-DetaN；

Act22_New＝Nref；

Act12_New＝Act12-DetaN；

where DetaN is the difference value and Nref is the reference value.

6. The method of claim 1, wherein the first current sampling trigger value and the second current sampling trigger value are determined according to the following equations when single resistance sampling is performed during the rise phase of a triangular carrier wave:

Trig1_New＝Act21_New-Tsample；

Trig2_New＝Act21_New+Tdead+Tup；

wherein, the Trig1_NewSampling a trigger value, Trig2, for the first current_NewAnd sampling the trigger value for the second current, wherein Tsample is the time required by hardware sampling, Tdead is the dead time, and Tup is the time for the current to rise to be stable.

7. The method of claim 1, wherein the first current sampling trigger value and the second current sampling trigger value are determined according to the following equations when single resistance sampling is performed during a falling phase of a triangular carrier wave:

Trig1_New＝Act22_New+Tsample；

Trig2_New＝Act22_New-Tdead-Tup；

8. A computer-readable storage medium, characterized in that a motor rotor position observation program is stored thereon, which, when being executed by a processor, implements the motor rotor position observation method according to any one of claims 1-7.

9. A rotor position observer, comprising a memory, a processor and an electric machine rotor position observation program stored on the memory and executable on the processor, when executing the electric machine rotor position observation program, implementing the electric machine rotor position observation method according to any one of claims 1-7.

10. An electric motor rotor position observation device, comprising:

a first determination module for determining a reference value;

the second determination module is used for determining six comparison values Act11, Act21, Act31, Act32, Act22 and Act12 of three-way modulation corresponding to the voltage vector required by the single-resistor sampling output;

the adjusting module is used for determining the difference value between the reference value and the comparison value Act21 or Act22 when high-frequency pulses are injected into the d shaft of the motor, and adjusting six comparison values Act11, Act21, Act31, Act32, Act22 and Act12 according to the difference value;

a third determination module for determining the adjusted comparison value Act21_NewOr Act22_NewDetermining a first current sampling trigger value and a second current sampling trigger value;

a control module for adjusting six comparison values Act11_New、Act21_New、Act31_New、Act32_New、Act22_New、Act12_NewControlling a motor, sampling the current of the motor according to the first current sampling trigger value and the second current sampling trigger value, obtaining a first sampling current and a second sampling current, and estimating the position of a rotor of the motor according to the first sampling current and the second sampling current.