CN111478629A - Position detection method and device of permanent magnet brushless direct current motor and electrical equipment - Google Patents

Abstract

The invention provides a position detection method and device of a permanent magnet brushless direct current motor and electrical equipment, wherein the position detection method of the permanent magnet brushless direct current motor comprises the following steps: collecting phase voltage of a motor to obtain a collected signal; comparing the collected signals through a comparator and outputting comparison signals; determining that the motor carries out phase change operation, and starting capture interruption; and confirming to execute at least one of back electromotive force zero-crossing detection and forced phase commutation according to the comparison signal acquired in the capture interruption. The position detection method can determine a counter potential zero-crossing detection point or a forced phase-change point, and is not influenced by rotation speed fluctuation.

Description

Position detection method and device of permanent magnet brushless direct current motor and electrical equipment

Technical Field

The invention relates to the technical field of motors, in particular to a position detection method of a permanent magnet brushless direct current motor, a position detection device of the permanent magnet brushless direct current motor and electrical equipment.

Background

Brushless dc motors have been used in a variety of fields because of their simple structure, high output and efficiency. In the traditional control technology of the brushless direct current motor without the position sensor, a hardware comparator is mostly adopted to compare the voltage of a motor terminal with the voltage of a neutral point, and the position of a back electromotive force zero crossing point is obtained through a comparison level output by the comparator, so that the commutation is realized.

However, in practice, when a square wave is used to drive the motor, there is a level of disturbance of the "false zero crossing" of the comparator output level caused by the commutation freewheel. These interference levels can cause misjudgment of the zero crossing point and cause phase change errors or even step loss. In addition, due to misjudgment of the zero-crossing point or rapid speed rise, the actual commutation point lags behind the ideal commutation point seriously, so that the next zero-crossing point is submerged and cannot be detected, and the commutation cannot be performed.

At present, for an interference level output by a comparator caused by commutation follow current, in the related art, a follow current section is shielded by setting a specific time, that is, zero-crossing detection logic is not enabled in the section of time, and zero-crossing detection is started after the time is over. Specifically, as shown in fig. 1, Van, Ha', and Ha are the terminal voltage of a certain phase, the comparator output signal with the free-wheeling interference level, and the processed comparator output signal, respectively. A cycle can be divided into 6 regions according to 6 zero crossings within a cycle of one of the opposite potentials. And (3) circularly timing by using a circular counter Time, reading the numerical value of Time when the acquisition and judgment of 6 regions are completed, calculating the period Time C, and calculating the Time Tw which cannot be detected in each region according to the period Time C. Before the next zero crossing point detection, counting operation is carried out according to Tw, the zero crossing detection is not enabled within the time Tw, and the enable signal EN is started to carry out the zero crossing detection after the Tw is finished.

However, referring to fig. 1, this scheme is to deduce the masking period Tw from the count value of the previous cycle. Therefore, to ensure that Tw can cover a proper position each time, i.e., longer than the freewheel time and shorter than the zero crossing time, it is necessary to establish that the rotation speed is stable and cannot change abruptly. If the rotating speed is unstable, the calculated 'avoidance free-wheeling time' is likely to be too long to cover the zero-crossing point (as shown in fig. 2), so that the zero-crossing point is detected in a lagging way, and the phase change is delayed; or too short to be effective (as shown in fig. 3), thereby causing the zero crossing point to be misjudged so as to lead the phase change to be excessively advanced, and finally causing the motor to lose step and even causing hardware damage due to improper phase change time. Therefore, the scheme is not suitable for occasions with unstable rotating speed, such as the need of rapid speed increase, frequent speed change, inaccurate rotating speed detection and the like.

Aiming at the situation that the zero crossing point is submerged due to the phase change lag, in the related technology, a maximum phase change time T is set, timing is started while the zero crossing point is detected, and forced phase change operation is carried out if the zero crossing point is not detected after the maximum phase change time T is exceeded, so that the stable operation of a system is ensured.

However, this solution is not suitable for use in the case of rapid acceleration. Because if the zero-crossing point is drowned out due to the phase change of the previous beat caused by the speed increase, the phase change is delayed more seriously and even out of step after the time T (the sum of the last four phase change time intervals) passes. As shown in fig. 4, even if the time T is shortened, the theoretical minimum value thereof can only satisfy that T is equal to or greater than the last detected zero-crossing time. In the case of a rapid speed increase, the minimum value T (time from the last commutation to the detection of the zero crossing point) is used for forced commutation, and it is still possible to make the commutation still lag behind, so that all the following counter potential zero crossing points cannot be detected in time, and thus forced commutation is frequently started until step loss occurs.

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, the first objective of the present invention is to provide a position detection method for a permanent magnet brushless dc motor.

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

The third purpose of the invention is to provide a position detection device of a permanent magnet brushless direct current motor.

The fourth purpose of the invention is to provide another position detection device of a permanent magnet brushless direct current motor.

A fifth object of the invention is to propose an electrical apparatus.

In order to achieve the above object, a first embodiment of the present invention provides a position detection method for a permanent magnet brushless dc motor, including the following steps: collecting phase voltage of a motor to obtain a collected signal; comparing the collected signals through a comparator, and outputting comparison signals; determining that the motor carries out phase change operation, and starting capture interruption; and confirming to execute at least one of back electromotive force zero-crossing detection and forced phase commutation according to the comparison signal acquired in the capture interruption.

According to the position detection method of the permanent magnet brushless direct current motor, when the motor carries out phase change operation, capture interruption is started, and at least one operation of back electromotive force zero-crossing detection and forced phase change is confirmed and executed according to a comparison signal acquired in the capture interruption. The method can determine the counter potential zero-crossing detection point or the forced phase-change point and is not influenced by the fluctuation of the rotating speed.

In addition, the position detection method of the permanent magnet brushless dc motor according to the above embodiment of the present invention may further have the following additional technical features:

according to an embodiment of the present invention, the comparing the collected signals by a comparator and outputting a comparison signal includes: determining that the phase voltage corresponding to the acquisition signal is greater than the neutral point voltage through the comparator, and outputting a high-level comparison signal; and determining that the phase voltage corresponding to the acquired signal is smaller than the neutral point voltage through the comparator, and outputting a low-level comparison signal.

According to an embodiment of the present invention, the confirming to perform counter potential zero crossing detection based on the comparison signal acquired in capturing the interrupt includes: determining to capture a level edge signal, and performing level confirmation on a comparison signal acquired after the level edge signal; confirming that the level of the comparison signal is a normal comparison level before a counter potential zero crossing point, and adding 1 to a level confirmation count value; determining that the level confirmation count value is greater than a threshold value of the level confirmation times, judging that the follow current period is finished, closing capture interruption, and executing counter potential zero-crossing detection; and determining that the level of the comparison signal is not the normal comparison level before the counter potential zero crossing point, judging that the level edge signal is a burr interference signal, resetting the level confirmation count value, and waiting for the next level edge signal again.

According to an embodiment of the present invention, a filter circuit is connected to an output terminal of the comparator to filter a comparison signal output from the comparator, and the counter potential zero crossing detection is confirmed to be performed based on the comparison signal acquired in the capture interrupt, further including: it is determined that a level edge signal is captured and the level change of the level edge signal is normal, the capture interrupt is turned off, and back-emf zero-crossing detection is performed.

According to an embodiment of the present invention, the confirming to perform forced commutation according to the comparison signal acquired in the capturing of the interrupt includes: and after the capture interruption is determined to be started and no level edge signal is captured in the forced commutation time, the capture interruption is closed and forced commutation is executed.

In order to achieve the above object, a second embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the above position detection method for a permanent magnet brushless dc motor.

According to the computer-readable storage medium of an embodiment of the present invention, when the computer program stored thereon is executed by the processor, the back electromotive force zero-crossing detection point or the forced phase change point can be determined without being affected by the rotation speed fluctuation.

In order to achieve the above object, a third embodiment of the present invention provides a position detecting apparatus for a permanent magnet brushless dc motor, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor executes the computer program to implement the position detecting method for the permanent magnet brushless dc motor.

According to the position detection apparatus of the permanent magnet brushless dc motor of the embodiment of the present invention, when the computer program stored on the memory thereof is executed by the processor, the back emf zero-crossing detection point or the forced phase-change point can be determined without being affected by the rotation speed fluctuation.

In order to achieve the above object, a fourth aspect of the present invention provides a position detecting device for a permanent magnet brushless dc motor, including: the acquisition module is used for acquiring phase voltage of the motor to obtain an acquisition signal; the comparison module is used for comparing the acquired signals through a comparator and outputting comparison signals; and the execution module is used for determining that the motor carries out phase change operation, starting capture interruption, and confirming to execute at least one of back electromotive force zero-crossing detection and forced phase change according to a comparison signal acquired in the capture interruption.

According to the position detection device of the permanent magnet brushless direct current motor, when the motor carries out phase change operation, the execution module starts capture interruption, and confirms to execute at least one operation of counter potential zero-crossing detection and forced phase change according to a comparison signal acquired in the capture interruption. The device can determine a counter potential zero-crossing detection point or a forced phase-change point and is not influenced by rotation speed fluctuation.

In addition, the position detection device of the permanent magnet brushless dc motor according to the above embodiment of the present invention may further have the following additional technical features:

according to an embodiment of the present invention, the comparing module is specifically configured to: determining that the phase voltage corresponding to the acquisition signal is greater than the neutral point voltage through the comparator, and outputting a high-level comparison signal; and determining that the phase voltage corresponding to the acquired signal is smaller than the neutral point voltage through the comparator, and outputting a low-level comparison signal.

In order to achieve the above object, a fifth embodiment of the present invention provides an electrical apparatus, including the position detecting device of the permanent magnet brushless dc motor.

According to the electric equipment provided by the embodiment of the invention, the counter potential zero-crossing detection point or the forced phase-change point can be determined by adopting the position detection device of the permanent magnet brushless direct current motor provided by the embodiment of the invention, and the influence of rotation speed fluctuation is avoided.

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

The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic diagram of signal processing in the related art;

FIG. 2 is a schematic diagram illustrating an excessive masking time estimated based on the related art shown in FIG. 1;

FIG. 3 is a schematic diagram showing that the masking time is excessively short based on the estimation in the related art shown in FIG. 1;

FIG. 4 is a schematic diagram of forced commutation in another related art;

fig. 5 is a flowchart of a position detection method of a permanent magnet brushless dc motor according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a process for performing zero crossing detection according to one embodiment of the present invention;

FIG. 7 is a flow chart of a method of position detection for a permanent magnet brushless DC motor in accordance with one embodiment of the present invention;

FIG. 8 is a schematic diagram of performing a forced commutation process according to one embodiment of the invention;

FIG. 9 is a schematic diagram of a process for performing zero crossing detection according to another embodiment of the present invention;

fig. 10 is a block diagram of a position detecting apparatus of a permanent magnet brushless dc motor according to an embodiment of the present invention;

fig. 11 is a block diagram showing a structure of a position detecting apparatus of a permanent magnet brushless dc motor according to another embodiment of the present invention;

fig. 12 is a block diagram of an electrical appliance according to an embodiment of the present 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.

A position detection method and apparatus of a permanent magnet brushless dc motor according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

Fig. 5 is a flowchart of a position detection method of a permanent magnet brushless dc motor according to an embodiment of the present invention.

As shown in fig. 5, the position detecting method of the permanent magnet brushless dc motor includes the following steps:

and S1, collecting the phase voltage of the motor to obtain a collected signal.

And S2, comparing the collected signals through a comparator, and outputting a comparison signal.

Specifically, as shown in fig. 6, if the phase voltage corresponding to the collected signal is greater than the neutral point voltage, the comparison signal output by the comparator is at a high level; and if the phase voltage corresponding to the acquisition signal is smaller than the neutral point voltage, the comparison signal output by the comparator is at a low level. Of course, the neutral point voltage is the zero point voltage.

And S3, determining that the motor carries out phase change operation, and starting capture interruption.

S4, confirming to execute at least one of back emf zero crossing detection and forced commutation according to the comparison signal acquired in the capture interrupt.

According to the position detection method of the permanent magnet brushless direct current motor, the back electromotive force zero-crossing detection point or the forced phase-change point can be determined directly according to the comparison signal, and the influence of rotating speed fluctuation is avoided.

Specifically, in one embodiment of the present invention, when a level edge signal is captured, level confirmation is performed on a comparison signal acquired after the level edge signal; if the level of the comparison signal is a normal comparison level before the back emf zero crossing point, the level confirmation count value count is increased by 1; judging whether the count is greater than N, wherein N is a threshold value of the level confirmation times and can be calibrated according to needs; if the count is larger than N, judging that the follow current time period is ended, closing capture interruption, and starting counter potential zero-crossing detection; and if the level of the comparison signal is not the normal comparison level before the back emf zero crossing point, judging that the level edge signal is a glitch interference signal, resetting the count, and waiting for the next level edge signal again.

Specifically, taking phase a of A, B, C as an example, as shown in fig. 6, Van is a terminal voltage of phase a with respect to ground, and Ha is a comparison level of comparison output by the comparator between Van and neutral point voltage Vn. As can be seen, after (100) or (101) commutation, the terminal voltage Van during the freewheeling period is clamped to the bus voltage (102) or ground (103) because the current in the inductor needs to freewheel. At this time, the comparator will output a high level (104) or a low level (105), i.e. a free-wheeling interference level, accordingly. And returning to normal comparison level output after the freewheeling period is ended. Therefore, if it can be known when the freewheel period ends, it is possible to ensure that the operation of zero-cross detection is turned on again after the freewheel ends.

Referring to fig. 6 and 7, after the commutation operation at 100, a freewheel period 102 is entered, at which time a Timer capture interrupt is started at 104 to wait for a level-down edge 105 of Ha after the end of the capture freewheel. And after the required level edge is successfully captured, sequentially confirming the level in the capture interruption, and if the judgment level is the normal comparison level 106 before the counter potential zero crossing point, adding 1 to the level confirmation count value count. If the count is greater than N, judging that the follow current time period is finished, closing Timer capture interruption and starting counter potential zero-crossing detection; if a normal comparison level before the non-zero crossing point is found in the level confirmation period, judging that the falling edge captured at the time is glitch interference, resetting the count, waiting for the next level falling edge again, and repeating the processes.

Similarly, after the same two phase-change operations (i.e. phase-change B and phase-change C), after phase-change 101, the freewheeling period will be immediately entered 103, at this time, a Timer capture interrupt is immediately started at 107, and the rising edge 108 of the level of Ha after the capture freewheeling is finished is waited. After the required level edge is successfully captured, confirming the level in the capture interrupt until the normal comparison output level 109 is detected and the level confirmation count value count is greater than N, closing the Timer capture interrupt, and starting the counter potential zero crossing point judgment; otherwise, the count value is cleared, the rising edge of the level is waited for capturing again, and the process is repeated. Where N is a threshold value of the number of level confirmations for filtering.

Therefore, the method of the embodiment avoids the follow current period directly according to the output level state of the comparator instead of estimating the shielding follow current period according to the rotating speed of the motor, namely, the method is independent of the rotating speed and is not influenced by the rotating speed fluctuation, a position sensor is not needed, and the interference of the follow current level can be accurately avoided even if the rotating speed is unstable.

In another embodiment of the present invention, after the capture interrupt is turned on, if no level edge signal is captured within the forced commutation time Tfc, the capture interrupt is turned off, and the forced commutation is turned on, where Tfc ═ k × T, k is an empirical coefficient whose value can be obtained experimentally, and T is an average commutation time.

Specifically, referring to fig. 7 and 8, taking phase a as an example, after phase-change operation at 200, a freewheel period of 201 is generated, and the corresponding comparison level is also flipped to a high level at this moment. Due to the hysteretic commutation, after the freewheel is over, the detected terminal voltage at 204 is already above the zero crossing comparison value, and the zero crossing is overwhelmed. That is, after the constant current level output from the comparator is ended, the level immediately after the zero-crossing of the back emf is detected, and the level inversion at the zero-crossing point of the back emf, that is, the zero-crossing point cannot be detected. Therefore, after the capture interruption is started at 203, a forced commutation time Tfc is set, if the level falling edge after the follow current is not captured until the follow current is finished is exceeded by the time Tfc, the commutation can be judged to be lagging, the capture interruption is closed, and the forced commutation is started immediately at 205 without waiting for an expected zero crossing point or finding no zero crossing point at the moment of the expected commutation point to start commutation.

Similarly, after the same two commutation operations, the capture interrupt is turned on at 206 immediately after 202 commutation, waiting for the rising edge of the level after the end of the capture freewheel. If the desired level edge signal is not captured beyond time Tfc, the capture interrupt is turned off and forced commutation is immediately turned on at 207.

Therefore, the problem that the zero crossing point is submerged due to the rapid speed rise of the motor, and the phase change is delayed until the step is lost is solved.

In another embodiment of the present invention, a filter circuit is connected to the output terminal of the comparator to filter the comparison signal output by the comparator. In this embodiment, when a level edge signal is captured and the level edge signal is a normal edge signal, the capture interrupt is turned off and the counter potential zero crossing detection is turned on.

Specifically, as shown in fig. 9, glitch interference may be generated at 301 or near the back-emf zero-crossing point due to PWM chopping, and the problem caused by glitch interference may be solved by connecting a hardware filter circuit to the output terminal of the comparator.

Referring to fig. 9, immediately after 300 commutation, capture is turned on to interrupt the falling edge level at the end of the capture freewheel. The desired falling edge phase will be delayed to some extent to 302 due to hardware filtering. In this embodiment, the capture interrupt may be turned off directly after the desired level edge is captured, turning on back-emf zero-crossing detection.

In summary, in the position detection method of the permanent magnet brushless dc motor according to the embodiment of the present invention, a position sensor is not required to be disposed, and after each phase change, the follow current level edge output by the comparator is determined, so that whether the current phase is in the follow current stage can be determined in real time; when the follow current level ending edge is not detected, the follow current level ending edge does not act until the follow current ending edge is captured, and after the level is confirmed to be a non-follow current level at the moment, back-emf zero-crossing detection is started, so that the follow current period is avoided, the influence of rotation speed fluctuation is avoided, and system resources are saved; and when the capture time exceeds a threshold value and the follow current level ending edge is not captured all the time, starting forced commutation, judging whether commutation lags or not in advance before a zero crossing point or a commutation point is expected, starting commutation, and widening the speed-up speed range.

Further, the present invention proposes a computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, implements the above-mentioned position detection method of a permanent magnet brushless dc motor.

According to the computer-readable storage medium of the embodiment of the invention, when the computer program stored on the computer-readable storage medium is executed by the processor, the back electromotive force zero-crossing detection can be started in a free-wheeling period, the influence of rotation speed fluctuation is avoided, the system resource is saved, and the speed-up speed range is widened.

Fig. 10 is a block diagram of a position detecting apparatus of a permanent magnet brushless dc motor according to an embodiment of the present invention.

As shown in fig. 10, the position detecting apparatus 1000 of the permanent magnet brushless dc motor includes a memory 110, a processor 120, and a computer program 130 stored in the memory 110 and operable on the processor, and when the processor 120 executes the program, the position detecting method of the permanent magnet brushless dc motor is implemented.

According to the position detection device of the permanent magnet brushless direct current motor, when the computer program stored on the memory of the position detection device is executed by the processor, the back electromotive force zero-crossing detection can be started in a follow current period, the influence of rotating speed fluctuation is avoided, meanwhile, system resources are saved, and the speed-up speed range is widened.

Fig. 11 is a block diagram of a position detecting apparatus of a permanent magnet brushless dc motor according to another embodiment of the present invention.

As shown in fig. 11, the position detecting apparatus 2000 of the permanent magnet brushless dc motor includes: an acquisition module 2100, a comparison module 2200, and an execution module 2300.

The acquisition module 2100 is configured to acquire phase voltages of a motor to obtain an acquisition signal; the comparison module 2200 is configured to compare the collected signals with a comparator and output a comparison signal; the execution module 2300 is configured to determine that the motor performs a commutation operation, start a capture interrupt, and confirm execution of at least one of a back emf zero crossing detection and a forced commutation according to a comparison signal obtained during the capture interrupt.

In an embodiment of the present invention, the comparing module 2200 is specifically configured to: determining that the phase voltage corresponding to the acquired signal is greater than the neutral point voltage through a comparator, and outputting a high-level comparison signal; and determining that the phase voltage corresponding to the acquired signal is smaller than the neutral point voltage through the comparator, and outputting a low-level comparison signal.

It should be noted that the above explanation of the embodiment of the position detection method for the permanent magnet brushless dc motor is also applicable to the position detection apparatus for the permanent magnet brushless dc motor in this embodiment, and is not repeated herein.

According to the position detection device of the permanent magnet brushless direct current motor, when the motor carries out phase change operation, the execution module starts capture interruption, and at least one operation of back electromotive force zero-crossing detection and forced phase change is confirmed to be executed according to a comparison signal acquired in the capture interruption. The device can determine a counter potential zero-crossing detection point or a forced phase-change point and is not influenced by rotation speed fluctuation.

Further, the invention provides an electrical device.

An electric device 3000 according to an embodiment of the present invention includes the position detection apparatus 1000 (shown in fig. 12) of the permanent magnet brushless dc motor according to the above-described embodiment, or the position detection apparatus 2000 of the permanent magnet brushless dc motor according to the above-described embodiment. Wherein the electrical device 2000 may be a blender, a wall breaking machine, etc.

According to the electric equipment provided by the embodiment of the invention, the position detection device of the permanent magnet brushless direct current motor provided by the embodiment of the invention can avoid starting counter potential zero-crossing detection in a follow current period, is not influenced by rotation speed fluctuation, saves system resources and widens the speed-up speed range.

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 are not necessarily intended to 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, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

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.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing steps of a custom logic function or process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.

The logic and/or steps represented in the flowcharts or otherwise described herein, e.g., 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. 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.

It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.

In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.

The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, 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 (10)

1. A position detection method of a permanent magnet brushless direct current motor is characterized by comprising the following steps:

collecting phase voltage of a motor to obtain a collected signal;

comparing the collected signals through a comparator, and outputting comparison signals;

determining that the motor carries out phase change operation, and starting capture interruption;

and confirming to execute at least one of back electromotive force zero-crossing detection and forced phase commutation according to the comparison signal acquired in the capture interruption.

2. The method of claim 1, wherein comparing the acquisition signals by a comparator and outputting a comparison signal comprises:

determining that the phase voltage corresponding to the acquisition signal is greater than the neutral point voltage through the comparator, and outputting a high-level comparison signal;

and determining that the phase voltage corresponding to the acquired signal is smaller than the neutral point voltage through the comparator, and outputting a low-level comparison signal.

3. The method of claim 1, wherein said confirming to perform back emf zero crossing detection based on the comparison signal captured in the capture interrupt comprises:

determining to capture a level edge signal, and performing level confirmation on a comparison signal acquired after the level edge signal;

confirming that the level of the comparison signal is a normal comparison level before a counter potential zero crossing point, and adding 1 to a level confirmation count value;

determining that the level confirmation count value is greater than a threshold value of the level confirmation times, judging that the follow current period is finished, closing capture interruption, and executing counter potential zero-crossing detection;

and determining that the level of the comparison signal is not the normal comparison level before the counter potential zero crossing point, judging that the level edge signal is a burr interference signal, resetting the level confirmation count value, and waiting for the next level edge signal again.

4. The method of claim 1, wherein a filter circuit is connected to an output of the comparator to filter a comparison signal output from the comparator, and wherein performing back-emf zero-crossing detection based on the comparison signal captured during the capture interrupt comprises:

it is determined that a level edge signal is captured and the level change of the level edge signal is normal, the capture interrupt is turned off, and back-emf zero-crossing detection is performed.

5. The method of claim 1, wherein said confirming to perform a forced commutation based on the comparison signal obtained in the acquisition interrupt comprises:

determining to turn on the capture interrupt and not capturing the level edge signal within the forced commutation time, turning off the capture interrupt, and performing the forced commutation.

6. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out a method for position detection of a permanent magnet brushless dc motor according to any one of claims 1-5.

7. A position detecting apparatus for a permanent magnet brushless dc motor, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the position detecting method for a permanent magnet brushless dc motor according to any one of claims 1 to 5.

8. A position detecting device of a permanent magnet brushless DC motor, comprising:

the acquisition module is used for acquiring phase voltage of the motor to obtain an acquisition signal;

the comparison module is used for comparing the acquired signals through a comparator and outputting comparison signals;

and the execution module is used for determining that the motor carries out phase change operation, starting capture interruption, and confirming to execute at least one of back electromotive force zero-crossing detection and forced phase change according to a comparison signal acquired in the capture interruption.

9. The apparatus of claim 8, wherein the comparison module is specifically configured to:

determining that the phase voltage corresponding to the acquisition signal is greater than the neutral point voltage through the comparator, and outputting a high-level comparison signal;

and determining that the phase voltage corresponding to the acquired signal is smaller than the neutral point voltage through the comparator, and outputting a low-level comparison signal.

10. An electrical apparatus, characterized in that it comprises a position detection device of a permanent magnet brushless dc motor according to any of claims 7-9.

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