CN114928305A

CN114928305A - Motor control method, device, equipment and storage medium

Info

Publication number: CN114928305A
Application number: CN202210557261.8A
Authority: CN
Inventors: 刘文龙; 徐云松; 胡斌; 龙谭; 毕然
Original assignee: GD Midea Air Conditioning Equipment Co Ltd; Foshan Shunde Midea Electric Science and Technology Co Ltd
Current assignee: GD Midea Air Conditioning Equipment Co Ltd; Foshan Shunde Midea Electric Science and Technology Co Ltd
Priority date: 2022-05-20
Filing date: 2022-05-20
Publication date: 2022-08-19

Abstract

The application discloses a control method, a control device, control equipment and a storage medium of a motor. The method comprises the following steps: responding to a starting instruction of the motor, and adjusting the duration of the continuous pulse width of each effective vector in the PWM signal of at least one PWM period to be larger than a set duration threshold; acquiring a current value of the motor corresponding to the at least one PWM period; and controlling the motor to execute overcurrent protection based on the current value, the time length threshold value and the set current threshold value. Therefore, the motor is driven by the adjusted PWM signal of at least one PWM period, the current value of the at least one PWM period is obtained, short-circuit faults between motor terminals can be effectively identified in the motor starting stage, potential safety hazards are eliminated based on overcurrent protection, and the operation safety of the motor in the starting stage is greatly improved.

Description

Motor control method, device, equipment and storage medium

Technical Field

The present application relates to the field of motor control technologies, and in particular, to a method, an apparatus, a device, and a storage medium for controlling a motor.

Background

With the active popularization of energy-saving and consumption-reducing technologies, the energy-saving technology of motor control is increasingly paid attention. For example, a variable frequency air conditioner employs a Permanent Magnet Synchronous Motor (PMSM) having low loss and high efficiency.

In the related art, as shown in fig. 1, a driving circuit of a PMSM includes: a Micro Controller Unit (MCU), an Intelligent Power Module (IPM), and an overcurrent protection circuit. The MCU is used for outputting u +, u-, v +, v-, w + and w-driving signals so as to drive the IPM to perform corresponding switching action; the IPM is used for receiving a driving signal and controlling the voltage output to a terminal U, V, W of the motor so as to drive the motor to run; the overcurrent protection circuit is used for detecting the current value in the IPM, outputting an overcurrent protection signal to the MCU when the overcurrent protection condition is met, and the MCU timely turns off the output of the driving signal based on the received overcurrent protection circuit signal to realize overcurrent protection.

In order to prevent false triggering of the overcurrent protection circuit due to the interference signal, a duration threshold Td is usually set, and when the detected current value reaches the current threshold Imax, the detected current value is still kept above Imax and lasts for Td to trigger the overcurrent protection. For example, as shown in fig. 2, the current starts to be output at time t0, the current reaches the current threshold Imax of the overcurrent protection at time t1, the current needs to be kept at the current threshold Imax until time t2 (that is, Td is t2-t1), the overcurrent protection circuit outputs the protection signal, the MCU turns off the output, and the current stops being output.

However, the mechanism for triggering the overcurrent protection is limited by the time length threshold Td, and it is difficult to trigger the overcurrent protection quickly under the condition that the motor terminal has a short-circuit fault, so that a peak current in a motor starting stage impacts the IPM, and the IPM and/or related devices may be damaged, thereby resulting in a potential safety hazard.

Disclosure of Invention

In view of this, embodiments of the present application provide a method, an apparatus, a device, a system, and a storage medium for controlling a motor, which aim to improve the operation safety of the motor in a starting stage.

The technical scheme of the embodiment of the application is realized as follows:

in a first aspect, an embodiment of the present application provides a control method for a motor, including:

responding to a starting command of the motor, and adjusting the duration of the pulse width of each effective vector in a Pulse Width Modulation (PWM) signal of at least one PWM period to be larger than a set duration threshold;

acquiring a current value of the motor corresponding to the at least one PWM period;

and controlling the motor to execute overcurrent protection based on the current value, the duration threshold and the set current threshold.

In some embodiments, the controlling the motor to perform overcurrent protection based on the current value, the duration threshold, and a set current threshold includes:

and if the duration that the current value reaches the current threshold is determined to be greater than or equal to the duration threshold, generating an overcurrent protection instruction, and executing overcurrent protection based on the overcurrent protection instruction.

In some embodiments, the controlling the motor to perform overcurrent protection based on the current value, the duration threshold, and a set current threshold further includes:

and if the current value does not reach the current threshold value or the duration of the current value reaching the current threshold value is smaller than the duration threshold value, the PWM signal is adjusted based on the driving algorithm.

In some embodiments, in adjusting the PWM signal based on the drive algorithm, the method further comprises:

acquiring a current value of the motor;

and controlling the motor to execute overcurrent protection based on the newly acquired current value, the duration threshold and the set current threshold.

In some embodiments, the at least one PWM period is a first PWM period to drive operation of the motor.

In a second aspect, an embodiment of the present application provides a control apparatus for an electric motor, including:

the adjusting module is used for responding to a starting instruction of the motor and adjusting the duration of the continuous pulse width of each effective vector in the PWM signal of at least one PWM period to be larger than a set duration threshold;

the acquisition module is used for acquiring a current value of the motor corresponding to the at least one PWM period;

and the control module is used for controlling the motor to execute overcurrent protection based on the current value, the duration threshold and a set current threshold.

In some embodiments, the control module is specifically configured to:

In some embodiments, the control module is further configured to:

In some embodiments, the control device is further configured to obtain a current value of the motor during the adjustment of the PWM signal based on the driving algorithm; the control module is also used for controlling the motor to execute overcurrent protection based on the newly acquired current value, the duration threshold and the set current threshold.

In a third aspect, an embodiment of the present application provides a control apparatus for a motor, including: a processor and a memory for storing a computer program capable of running on the processor, wherein the processor, when running the computer program, is configured to perform the steps of the method according to the first aspect of the embodiments of the present application.

In a fourth aspect, an embodiment of the present application provides a storage medium, where a computer program is stored on the storage medium, and when the computer program is executed by a processor, the steps of the method in the first aspect of the embodiment of the present application are implemented.

According to the technical scheme provided by the embodiment of the application, in response to a starting instruction of the motor, the duration of the continuous pulse width of each effective vector in the PWM signal of at least one PWM period is adjusted to be larger than a set duration threshold; acquiring a current value of the motor corresponding to at least one PWM period; and controlling the motor to execute overcurrent protection based on the current value, the time length threshold value and the set current threshold value. Therefore, the motor is driven through the PWM signal of at least one regulated PWM period, the current value of the at least one PWM period is obtained, the short-circuit fault between the motor terminals can be effectively identified in the motor starting stage, potential safety hazards are eliminated based on overcurrent protection, and the operation safety of the motor in the starting stage is greatly improved.

Drawings

FIG. 1 is a schematic diagram of a PMSM and a driving circuit thereof in the related art;

FIG. 2 is a schematic diagram of a motor triggered overcurrent protection in the related art;

FIG. 3 is a schematic view showing a structure in which a short-circuit fault occurs between terminals of a motor in the related art

FIG. 4 is a schematic diagram illustrating a relationship between a PWM signal and a current value of the IPM during a starting phase of the motor;

fig. 5 is a schematic flowchart of a control method of a motor according to an embodiment of the present application;

FIG. 6 is a diagram illustrating a relationship between an IPM current value and an adjusted PWM signal according to an embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of a control device of a motor according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of a control device of a motor according to an embodiment of the present application.

Detailed Description

The present application will be described in further detail with reference to the following drawings and examples.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

In the related art, when a short-circuit fault exists at a motor terminal, the current in the IPM may not pass through the motor, and the direct current flows back to the power supply terminal, resulting in a great current surge. For example, as shown in fig. 3, when there is a short-circuit fault between U, V terminals of the motor, if the MCU sends a u +, v-on signal, the current flows from the positive pole of the power supply back to the negative pole of the power supply directly through the IPM, causing a large current surge. Illustratively, the over-current protection circuit may detect the current value in the IPM based on the sampling resistance R at the power supply cathode.

It should be noted that, in the starting stage of the motor, an effective Pulse width (i.e., a duration of a Pulse width modulation) of a PWM (Pulse width modulation) signal sent by the MCU is small, and a current value acquired by the overcurrent protection circuit cannot simultaneously satisfy the conditions of the current threshold Imax and the duration threshold Td, so that the overcurrent protection cannot be triggered. However, large peak currents may cause the IPM to quickly accumulate heat, thereby causing thermal breakdown, creating a fire or shock safety risk.

Exemplarily, fig. 4 shows a relationship between a PWM signal issued by the MCU and the current value I of the IPM. Defining a three-bit binary number (abc) which respectively represents the switching states of upper bridge arms (PWM _ u +, PWM _ v + and PWM _ w +) of the IPM three-phase bridge inverter circuit, for example, 111 represents that the three upper bridge arms are all conducted, 000 represents that the three lower bridge arms are conducted, and 000 and 111 are collectively called zero vectors and do not generate effective output; 100. 010, 001, 110, 011, 101, collectively referred to as active vectors; since each PWM cycle consists of two zero vectors (000, 111) and two active vectors (also referred to as non-zero vectors), 100 and 110 active vectors are selected in fig. 4 for illustration. The duration of the pulse width (i.e., the duration of the operation) of the initial effective vectors 100 and 110 is small and gradually increases, and the current value I of the IPM also gradually increases. If the motor is in the short-circuit fault state shown in fig. 3, the IPM may generate a plurality of currents with large amplitudes, but the duration of the currents cannot meet the duration threshold Td, and then the overcurrent protection cannot be triggered. The accumulation of heat may cause IPM thermal breakdown damage, making the machine a safety hazard during the start-up phase.

Based on this, in various embodiments of this application, in order to take precautions against the potential safety hazard that overcurrent protection untimely leads to when having short-circuit fault between the motor terminal, through the PWM signal of at least one PWM cycle of adjusting the motor in the start-up stage, can effectively discern the short-circuit fault between the motor terminal to stop the potential safety hazard based on overcurrent protection.

The embodiment of the application provides a control method of a motor, wherein the motor can be a PMSM, the control method is applied to control equipment of the motor, and for example, the control equipment can be an MCU of the motor. As shown in fig. 5, the method includes:

step 501, responding to a starting instruction of a motor, and adjusting the duration of the continuous pulse width of each effective vector in the PWM signal of at least one PWM period to be larger than a set duration threshold.

Here, the control device of the motor may start the motor based on the start instruction, for example, after the control device is powered on, the control device sends a PWM signal for driving the motor to the IPM of the motor, and the IPM supplies power to the motor terminal to drive the motor to operate.

For example, the control device adjusts the duration of the pulse width of each effective vector in the PWM signal of at least one PWM period in the motor starting phase to be larger than a set time threshold. The set time length threshold may be the aforementioned time length threshold Td for overcurrent protection.

For example, as shown in fig. 6, the control device can adjust the PWM signal for the first PWM cycle of the motor start phase such that the pulse width durations of the active vectors 100 and 110 are each greater than the duration threshold Td.

And 502, acquiring a current value of the motor corresponding to the at least one PWM period.

Illustratively, the obtained current value is a current value of IPM of the motor.

In an application example, the driving circuit of the motor includes an overcurrent protection circuit, and the overcurrent protection circuit may detect a current value of the IPM, for example, the current value in the IPM may be detected based on the sampling resistor R at the power source cathode, so as to obtain a current value of the motor corresponding to the at least one PWM cycle.

And 503, controlling the motor to execute overcurrent protection based on the current value, the duration threshold and the set current threshold.

Here, the set current threshold may be the aforementioned current threshold Imax for overcurrent protection.

It should be noted that, if there is a short-circuit fault between the motor terminals, that is, when the motor is in an abnormal state, the large pulse width voltage (i.e., the effective vector) output by the PWM signal of the at least one PWM period directly flows back to the power supply terminal through the motor short-circuit point, and because there is no action of the motor inductance, the current of the IPM reaches the current threshold Imax of the overcurrent protection, and meanwhile, because the pulse width duration of the effective vector is greater than the duration threshold Td of the overcurrent protection, the overcurrent protection signal can be effectively triggered in this state, so that the detection of the short-circuit state can be realized, the overcurrent protection of the motor can be triggered, further, the faults such as thermal breakdown and the like caused by the heat accumulation of the IPM can be prevented, and the operation safety of the motor at the start-up stage can be improved.

It can be understood that, in the embodiment of the application, the current value of at least one PWM cycle is obtained through the regulated PWM signal of at least one PWM cycle, so that the short-circuit fault between the motor terminals can be effectively identified in the starting stage of the motor, potential safety hazards are eliminated based on overcurrent protection, and the operation safety of the motor in the starting stage is greatly improved.

Illustratively, the controlling the motor to perform overcurrent protection based on the current value, the time duration threshold and the set current threshold includes:

Here, determining that the current value reaches the current threshold value means determining that the current value is greater than or equal to the current threshold value.

For example, as shown in fig. 6, if there is a short-circuit fault between terminals U and V and/or between terminals U and W of the motor, in a case that a duration of a pulse width of the effective vector 100 is greater than a duration threshold Td, a current value I of the IPM reaches a current threshold Imax, and the duration is greater than or equal to the duration threshold Td, so that the overcurrent protection circuit may output an overcurrent protection instruction to the MCU based on the detected current value, and the MCU turns off the output, thereby implementing overcurrent protection of the motor; if a short-circuit fault exists between the terminals U and W and/or between the terminals V and W of the motor, under the condition that the duration of the pulse width of the effective vector 110 is greater than the duration threshold Td, the current value I of the IPM reaches the current threshold Imax, and the duration is greater than or equal to the duration threshold Td, so that the overcurrent protection circuit can output an overcurrent protection instruction to the MCU based on the detected current value, and the MCU turns off the output, thereby implementing overcurrent protection of the motor.

It is understood that, in other embodiments, the control apparatus may determine, based on the obtained current value of the IPM, that a duration of time for which the current value reaches the current threshold value is greater than or equal to a duration threshold value, generate an overcurrent protection instruction, and perform overcurrent protection, for example, turn off the output of the driving signal.

It should be noted that, in the embodiment of the present application, a PWM signal in one PWM cycle corresponds to two food-free amounts and two effective vectors, and as long as the duration of the continuous pulse width of the two effective vectors in the PWM signal in at least one PWM cycle is adjusted to be greater than a set duration threshold, when a short-circuit fault occurs at any two terminals of the motor, overcurrent protection can be triggered.

Illustratively, the at least one PWM period may be any one PWM period at the beginning of the start of the motor, and preferably, the at least one PWM period may be the first PWM period for driving the motor to operate. Therefore, aiming at the short-circuit fault, the overcurrent protection can be quickly and effectively realized at the beginning of the starting of the motor, and the potential safety hazard is avoided.

Illustratively, the controlling the motor to perform overcurrent protection based on the current value, the time duration threshold and a set current threshold further includes:

In an application example, the PWM signal of the first PWM period for driving the motor to operate may be adjusted to the aforementioned large-pulse-width output signal, that is, the duration of the two effective vectors in the PWM signal is greater than the set duration threshold, and if the motor is in a normal state (no short-circuit fault exists), the voltage output by the IPM flows back to the power supply end through the motor winding.

Here, the adjustment of the PWM signal based on the driving algorithm may be to control the start and operation of the motor by using a Space Vector Pulse Width Modulation (SVPWM), where the SVPWM is derived from an idea of tracking a stator flux linkage of the ac motor, and is easy to implement by a digital controller, and has the advantages of good output current waveform, high voltage utilization rate of a dc link, and the like, and the embodiment of the present application does not limit the foregoing.

In the process of regulating the PWM signal based on the driving algorithm, the control method may further comprise:

acquiring a current value of the motor;

Exemplarily, in the operation process of the motor, the overcurrent protection circuit can detect the current value of the IPM, and generate an overcurrent protection instruction to the MCU after the current value reaches the current threshold Imax and the duration threshold Td, and the MCU turns off the output to realize the overcurrent protection of the motor, thereby ensuring the safe and reliable operation of the motor.

In order to implement the method of the embodiment of the present application, the embodiment of the present application further provides a control device for a motor, where the control device for a motor corresponds to the control method for a motor, and each step in the control method for a motor is also completely applicable to the control device for a motor.

As shown in fig. 7, the control device of the motor includes: an adjustment module 701, an acquisition module 702, and a control module 703. The adjusting module 701 is used for responding to a starting instruction of the motor, and adjusting the duration of the continuous pulse width of each effective vector in the PWM signal of at least one PWM period to be larger than a set duration threshold; the obtaining module 702 is configured to obtain a current value of the motor corresponding to the at least one PWM period; the control module 703 is configured to control the motor to perform overcurrent protection based on the current value, the duration threshold, and a set current threshold.

In some embodiments, the control module 703 is specifically configured to:

In some embodiments, the control module 703 is further configured to:

In some embodiments, the obtaining module 702 is further configured to obtain a current value of the motor during the process of adjusting the PWM signal by the control device 703 based on the driving algorithm; the control module 703 is further configured to control the motor to perform overcurrent protection based on the newly acquired current value, the duration threshold, and the set current threshold.

In some embodiments, the at least one PWM period is a first PWM period to drive the motor to operate.

It should be noted that: in the motor control device provided in the above embodiment, only the division of the program modules is exemplified when the motor control is performed, and in practical applications, the processing distribution may be completed by different program modules according to needs, that is, the internal structure of the device may be divided into different program modules to complete all or part of the processing described above. In addition, the control device of the motor and the control method of the motor provided in the above embodiments belong to the same concept, and the specific implementation process thereof is described in detail in the method embodiments, and is not described again here.

Based on the hardware implementation of the program module, and in order to implement the method of the embodiment of the present application, the embodiment of the present application further provides a control device for a motor. Fig. 8 shows only an exemplary structure of the control apparatus of the motor, not the entire structure, and a part of or the entire structure shown in fig. 8 may be implemented as necessary.

As shown in fig. 8, a control apparatus 800 of a motor provided in an embodiment of the present application includes: at least one processor 801, a memory 802, and a user interface 803. The various components in the control device 800 of the motor are coupled together by a bus system 804. It will be appreciated that the bus system 804 is used to enable communications among the components. The bus system 804 includes a power bus, a control bus, and a status signal bus in addition to a data bus. For clarity of illustration, however, the various buses are labeled as bus system 804 in FIG. 8.

The user interface 803 may include, among other things, a display, a keyboard, a mouse, a trackball, a click wheel, a key, a button, a touch pad, or a touch screen.

The memory 802 in the embodiment of the present application is used to store various types of data to support the operation of the control device of the motor. Examples of such data include: any computer program for operating on a control device of an electric machine.

The phase current acquisition disclosed by the embodiment of the present application can be applied to the processor 801 or implemented by the processor 801. The processor 801 may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of phase current acquisition may be performed by instructions in the form of hardware integrated logic circuits or software in the processor 801. The Processor 801 may be a general purpose Processor, a Digital Signal Processor (DSP), or other programmable logic device, discrete gate or transistor logic device, discrete hardware components, or the like. The processor 801 may implement or perform the methods, steps, and logic blocks disclosed in the embodiments of the present application. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of the method disclosed in the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software modules may be located in a storage medium located in the memory 802, and the processor 801 reads the information in the memory 802, and completes the phase current collection steps provided in the embodiments of the present application in conjunction with its hardware.

In an exemplary embodiment, the control Device of the motor may be implemented by one or more Application Specific Integrated Circuits (ASICs), DSPs, Programmable Logic Devices (PLDs), Complex Programmable Logic Devices (CPLDs), Field Programmable Gate Arrays (FPGAs), general purpose processors, controllers, Micro Controllers (MCUs), microprocessors (microprocessors), or other electronic components for performing the aforementioned methods.

It will be appreciated that the memory 802 can be either volatile memory or nonvolatile memory, and can include both volatile and nonvolatile memory. Among them, the nonvolatile Memory may be a Read Only Memory (ROM), a Programmable Read Only Memory (PROM), an Erasable Programmable Read-Only Memory (EPROM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a magnetic random access Memory (FRAM), a magnetic random access Memory (Flash Memory), a magnetic surface Memory, an optical Disc, or a Compact Disc Read-Only Memory (CD-ROM); the magnetic surface storage may be disk storage or tape storage. Volatile Memory can be Random Access Memory (RAM), which acts as external cache Memory. By way of illustration and not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Synchronous Static Random Access Memory (SSRAM), Dynamic Random Access Memory (DRAM), Synchronous Dynamic Random Access Memory (SDRAM), Double Data Rate Synchronous Dynamic Random Access Memory (DDRSDRAM), Enhanced Synchronous Dynamic Random Access Memory (ESDRAM), Enhanced Synchronous Dynamic Random Access Memory (Enhanced DRAM), Synchronous Dynamic Random Access Memory (SLDRAM), Direct Memory (DRmb Access), and Random Access Memory (DRAM). The memories described in the embodiments of the present application are intended to comprise, without being limited to, these and any other suitable types of memory.

Illustratively, the control device of the embodiment of the present application may include the MCU shown in fig. 1.

In an exemplary embodiment, the present application further provides a storage medium, that is, a computer storage medium, which may be a computer readable storage medium, for example, a memory 802 storing a computer program, where the computer program is executable by a processor 801 of a control device to complete the steps of the method of the present application. The computer readable storage medium may be a ROM, PROM, EPROM, EEPROM, Flash Memory, magnetic surface Memory, optical disk, or CD-ROM, among others.

It should be noted that: "first," "second," and the like are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

The technical means described in the embodiments of the present application may be arbitrarily combined without conflict.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of controlling a motor, comprising:

responding to a starting instruction of the motor, and adjusting the duration of the continuous pulse width of each effective vector in the PWM signal of at least one Pulse Width Modulation (PWM) period to be larger than a set duration threshold;

2. The method of claim 1, wherein the controlling the motor to perform over-current protection based on the current value, the duration threshold, and a set current threshold comprises:

3. The method of claim 2, wherein the controlling the motor to perform over-current protection based on the current value, the time duration threshold, and a set current threshold further comprises:

4. The method of claim 3, wherein in adjusting the PWM signal based on the drive algorithm, the method further comprises:

acquiring a current value of the motor;

5. The method according to any one of claims 1 to 4,

the at least one PWM period is a first PWM period to drive the motor to operate.

6. A control device of a motor, characterized by comprising:

and the control module is used for controlling the motor to execute overcurrent protection based on the current value, the duration threshold and the set current threshold.

7. The control device of claim 6, wherein the control module is specifically configured to:

8. The control device of claim 7, wherein the control module is further configured to:

9. The control device according to claim 6, wherein the obtaining module is further configured to obtain a current value of the motor during the control device adjusts the PWM signal based on the driving algorithm; the control module is also used for controlling the motor to execute overcurrent protection based on the newly acquired current value, the duration threshold and the set current threshold.

10. The control device according to any one of claims 6 to 9,

11. A control apparatus of a motor, characterized by comprising: a processor and a memory for storing a computer program capable of running on the processor, wherein,

the processor, when executing the computer program, is configured to perform the steps of the method of any of claims 1 to 5.

12. A storage medium having a computer program stored thereon, the computer program, when executed by a processor, implementing the steps of the method of any one of claims 1 to 5.