Motor control switching method and control circuit thereof

Abstract

The invention discloses a motor control switching method and a control circuit thereof, and the method comprises the steps: determining a real-time motor control mode, collecting a system current and a system voltage based on the real-time motor control mode, and calculating the rotating speed of a motor based on the system current and the system voltage; the motor rotating speed is compared with a preset speed threshold value, motor control modes are switched based on a comparison result and a real-time motor control mode, and the motor control modes comprise square wave control and FOC control. Smooth switching of motor control modes is achieved by monitoring the rotating speed of the motor in real time and comparing the rotating speed according to the preset speed threshold value. Square wave control is adopted at a low speed to improve efficiency, and FOC control is switched at a high speed to improve control precision and dynamic response. By collecting system current and system voltage, the rotating speed of the motor is calculated, smooth transition is conducted in the switching process, and it is ensured that the motor stably operates under the large-load working condition within the full-speed range.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a motor control switching method and a control circuit thereof. Background Art

[0002] At present, in Sensorless Pmsm (sensorless permanent magnet synchronous motor) control, the market demand for the cost-effectiveness of motor control products is getting higher and higher, so the application of sensorless FOC vector control and sensorless square wave is generated. Compared with the sensory control method, the sensorless control method has the advantages of low cost and low complexity of motor installation, but the relative disadvantages are also obvious, especially in terms of algorithm complexity. The advantages of sensorless FOC vector control are high efficiency and low noise under load state, and the disadvantage is weak low-speed load capacity. More complex observers are needed to improve low-speed load capacity, such as high-frequency injection. The advantages of sensorless square wave are strong low-speed load capacity (no high-frequency injection is required) and high motor versatility, and the disadvantage is high noise.

[0003] The existing permanent magnet synchronous motor speed sensorless control method switches between sensorless square wave control and sensorless FOC vector control through electrical cycles. Although it can realize the control conversion of the permanent magnet synchronous motor, it cannot adjust according to the motor speed in real time during switching, and cannot smoothly perform control conversion. Summary of the invention

[0004] The present invention provides a motor control switching method and a control circuit thereof, which can smoothly switch the motor control mode and realize the heavy load operation control within the full speed range of the motor.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a motor control switching method, comprising:

[0006] Determine a real-time motor control mode, collect a system current and a system voltage based on the real-time motor control mode, and calculate a motor speed based on the system current and the system voltage;

[0007] The motor speed is compared with a preset speed threshold, and the motor control mode is switched based on the comparison result and the real-time motor control mode, wherein the motor control mode includes square wave control and FOC control.

[0008] The present invention realizes smooth switching of motor control modes by real-time monitoring of motor speed and comparison based on preset speed thresholds. Square wave control is used at low speed to improve efficiency, and FOC control is switched to at high speed to improve control accuracy and dynamic response. By collecting system current and system voltage, the motor speed is calculated, and a smooth transition is performed during the switching process to ensure stable operation of the motor under heavy load conditions within the full speed range.

[0009] Further, the collecting of system current and system voltage based on the real-time motor control mode, and calculating the motor speed based on the system current and the system voltage, includes:

[0010] When the real-time motor control mode is FOC control, the system current is collected, and the motor speed is calculated based on the system current;

[0011] When the real-time motor control mode is square wave control, the system voltage is collected, and the motor speed is calculated based on the system voltage.

[0012] Furthermore, when the real-time motor control mode is FOC control, collecting the system current and calculating the motor speed based on the system current include:

[0013] When the real-time motor control mode is FOC control, a first component current and a second component current of the three-phase current of the motor are collected based on a sampling resistor;

[0014] Performing coordinate transformation on the first component current and the second component current to obtain a D-axis current and a Q-axis current;

[0015] The motor speed and the motor position are calculated based on the D-axis current, the Q-axis current, the motor resistance and the motor inductance.

[0016] Further, switching the motor control mode based on the comparison result and the real-time motor control mode includes:

[0017] If the motor speed is less than the speed threshold and the real-time motor control mode is FOC control, the motor control mode is switched to square wave control.

[0018] Furthermore, when the real-time motor control mode is square wave control, collecting the system voltage and calculating the motor speed based on the system voltage includes:

[0019] When the real-time motor control mode is square wave control, detecting the back electromotive force of the suspended phase of the motor, and acquiring the motor zero-crossing signal based on the back electromotive force of the suspended phase;

[0020] The motor is controlled to perform commutation operation based on the motor zero-crossing signal and the six-step commutation control method, and the motor speed is calculated based on the motor zero-crossing signal.

[0021] Further, switching the motor control mode based on the comparison result and the real-time motor control mode includes:

[0022] If the motor speed is greater than or equal to the speed threshold and the real-time motor control mode is square wave control, the motor control mode is switched to FOC control.

[0023] In a second aspect, the present invention provides a control circuit of a motor control switching method, which is used to implement the motor control switching method, including: a power supply module, a current sampling module, a power switch module, a control module, an ADC sampling module and a motor;

[0024] The power supply module is electrically connected to the control module and the power switch module; the control module is electrically connected to the power switch module, the ADC sampling module and the current sampling module; the power switch module is electrically connected to the current sampling module, the ADC sampling module and the motor; the ADC sampling module is electrically connected to the motor;

[0025] The power supply module is used to supply power to the control module and the power switch module; the current sampling module is used to collect the three-phase current of the motor; the power switch module is used to control the motor; the ADC sampling module is used to collect the three-phase voltage of the motor; the control module is used to calculate the motor speed and switch the motor control mode.

[0026] Furthermore, the power module also includes a DCDC converter;

[0027] The DCDC converter is electrically connected to the control module and the ADC sampling module.

[0028] Further, the power switch module includes a three-phase inverter;

[0029] The three-phase inverter includes six MOSFET tubes.

[0030] Furthermore, the current sampling module includes a first sampling resistor, a second sampling resistor, a first comparator and a second comparator;

[0031] A first end of the first sampling resistor is electrically connected to the power switch module, and a first end of the second sampling resistor is electrically connected to the power switch module;

[0032] The non-inverting input terminal of the first comparator is electrically connected to the power switch module, and the non-inverting input terminal of the second comparator is electrically connected to the power switch module;

[0033] The non-inverting input terminal of the first comparator is electrically connected to the first end of the first sampling resistor, and the non-inverting input terminal of the second comparator is electrically connected to the first end of the second sampling resistor;

[0034] The inverting input terminal of the first comparator is electrically connected to the second end of the first sampling resistor, and the inverting input terminal of the second comparator is electrically connected to the second end of the second sampling resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic flow chart of a motor control switching method provided by an embodiment of the present invention;

[0036] Figure 2 Another structural schematic diagram of a motor control switching method provided by an embodiment of the present invention;

[0037] Figure 3 A structural schematic diagram of a control circuit of a motor control switching method provided by an embodiment of the present invention;

[0038] Figure 4 Another structural schematic diagram of a control circuit of a motor control switching method provided by an embodiment of the present invention;

[0039] Figure 5 A non-inductive FOC switching non-inductive square wave current waveform diagram provided by an embodiment of the present invention;

[0040] Figure 6 An inductive square wave switching inductive FOC current waveform diagram provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0042] The terms "first" and "second" and the like in the specification, claims and drawings of this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0043] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0044] First, some terms in this application are explained to facilitate understanding by those skilled in the art.

[0045] (1) ADC (Analog-to-Digital Converter) is a circuit that converts analog signals into digital signals.

[0046] (2) MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is a semiconductor device widely used in electronic circuits.

[0047] (3) FOC control (Field-Oriented Control) Field-oriented control (FOC), also known as vector control, is an advanced motor control technology that is widely used in the control of AC motors (such as induction motors and permanent magnet synchronous motors).

[0048] Example 1

[0049] See also Figure 1 , Figure 1 A flow chart of a motor control switching method provided by an embodiment of the present invention. The present invention provides a motor control switching method, including steps 101 to 102, which are as follows:

[0050] Step 101: determining a real-time motor control mode, collecting a system current and a system voltage based on the real-time motor control mode, and calculating a motor speed based on the system current and the system voltage;

[0051] Step 102: comparing the motor speed with a preset speed threshold, and switching the motor control mode based on the comparison result and the real-time motor control mode, wherein the motor control mode includes square wave control and FOC control.

[0052] Please refer to Figure 2 , Figure 2 Another structural schematic diagram of a motor control switching method provided by an embodiment of the present invention.

[0053] In this embodiment, by real-time monitoring of the motor speed and comparing it with a preset speed threshold, smooth switching of the motor control mode is achieved. Square wave control is used at low speed to improve efficiency, and FOC control is switched to at high speed to improve control accuracy and dynamic response. By collecting system current and system voltage, the motor speed is calculated, and a smooth transition is performed during the switching process to ensure stable operation of the motor under heavy load conditions within the full speed range.

[0054] In this embodiment, after detecting that the system has no faults, voltage sampling and current sampling are performed on the system to calculate the motor speed SPD, and the motor speed is compared with the threshold speed to determine the motor control mode based on the motor speed.

[0055] In this embodiment, the collecting of system current and system voltage based on the real-time motor control mode, and calculating the motor speed based on the system current and the system voltage include:

[0056] When the real-time motor control mode is FOC control, the system current is collected, and the motor speed is calculated based on the system current;

[0057] When the real-time motor control mode is square wave control, the system voltage is collected, and the motor speed is calculated based on the system voltage.

[0058] In this embodiment, the advantages of sensorless square wave control and sensorless FOC control are combined. In the high-speed state, sensorless FOC is used to control the motor so that the motor efficiency is high and the noise is low under load; in the low-speed state, sensorless square wave is used to control the motor to improve the low-load capacity and versatility of the motor; the real-time speed of the motor is calculated by real-time acquisition of system voltage and system current, and the motor control mode is switched based on the real-time speed of the motor, thereby realizing large-load operation control within the full speed range of the motor.

[0059] In this embodiment, when the real-time motor control mode is FOC control, collecting the system current and calculating the motor speed based on the system current include:

[0060] When the real-time motor control mode is FOC control, a first component current and a second component current of the three-phase current of the motor are collected based on a sampling resistor;

[0061] Performing coordinate transformation on the first component current and the second component current to obtain a D-axis current and a Q-axis current;

[0062] The motor speed and the motor position are calculated based on the D-axis current, the Q-axis current, the motor resistance and the motor inductance.

[0063] In this embodiment, when the motor control mode is FOC control, the three-phase current of the motor is collected, and the three-phase current is converted into the current in the stationary αβ coordinate system based on the Clark transformation, and then based on the Park transformation: the current in the αβ coordinate system is converted into the current in the rotating DQ coordinate system, so that the D-axis current and the Q-axis current are adjusted through the control module, and a PWM signal is generated to drive the inverter to adjust the phase voltage of the motor.

[0064] In this embodiment, after obtaining the D-axis current and the Q-axis current, the motor speed and real-time position are calculated based on the motor flux, the D-axis output voltage, the Q-axis output voltage, the motor resistance, and the motor inductance. Specifically:

[0065]

[0066]

[0067] Among them, f is the motor flux, U d is the D-axis output voltage, U q is the Q-axis output voltage, R is the motor resistance, L is the motor inductance, I d is the D-axis current, I q is the Q-axis current, W r is the motor speed.

[0068] In this embodiment, the motor speed W is obtained based on the D-axis current and the Q-axis current. r , for motor speed W r The motor position can be obtained by integration.

[0069] In this embodiment, the D-axis current and Q-axis current of the motor are controlled by sensorless FOC, and the motor speed and position are calculated to achieve precise speed and position control of the motor while reducing cost and complexity.

[0070] In this embodiment, switching the motor control mode based on the comparison result and the real-time motor control mode includes:

[0071] If the motor speed is less than the speed threshold and the real-time motor control mode is FOC control, the motor control mode is switched to square wave control.

[0072] In this embodiment, when the real-time motor control mode is square wave control, collecting the system voltage and calculating the motor speed based on the system voltage include:

[0073] When the real-time motor control mode is square wave control, detecting the back electromotive force of the suspended phase of the motor, and acquiring the motor zero-crossing signal based on the back electromotive force of the suspended phase;

[0074] The motor is controlled to perform commutation operation based on the motor zero-crossing signal and the six-step commutation control method, and the motor speed is calculated based on the motor zero-crossing signal.

[0075] In this embodiment, the back electromotive force of the suspended phase of the motor is collected based on the ADC sampling circuit, that is, the voltage sampling is performed in the non-driven phase (that is, the phase that is not energized). For example, if the current energized phase is the U phase, the voltages of the V phase and the W phase can be sampled.

[0076] In this embodiment, the voltage values ​​of adjacent sampling points are compared to determine whether the voltage changes. When it is detected that the voltage changes from negative to positive or from positive to negative, it means that the zero crossing point of the back electromotive force is detected. The zero crossing point moment is recorded, a zero crossing signal is generated, the commutation moment of the motor is determined based on the zero crossing signal, and the motor is controlled to perform commutation operation according to the six-step commutation control method.

[0077] In this embodiment, the commutation time of the motor is determined according to the detected zero-crossing point, and the switching state of the inverter is adjusted, thereby realizing the commutation operation of the motor.

[0078] In this embodiment, the rotation speed of the motor is calculated by detecting the time interval of the zero-crossing signal.

[0079] In this embodiment, each time a zero crossing is detected, the current timestamp is recorded, the time interval between adjacent zero crossings is calculated, and the motor speed is calculated based on the speed formula, specifically:

[0080]

[0081] Where N is the number of motor pole pairs and T is the zero-crossing period.

[0082] In this embodiment, by sampling the voltage in the non-driving phase and detecting the zero-crossing point of the back-EMF signal, the accuracy and reliability of the sampling signal are improved, thereby performing smooth commutation operation on the motor and calculating the rotation speed of the motor.

[0083] In this embodiment, switching the motor control mode based on the comparison result and the real-time motor control mode includes:

[0084] If the motor speed is greater than or equal to the speed threshold and the real-time motor control mode is square wave control, the motor control mode is switched to FOC control.

[0085] In this embodiment, in the sensorless square wave control, the motor speed is calculated in real time, and when the motor speed is greater than or equal to the speed threshold, the motor control mode is switched to FOC control.

[0086] In this embodiment, by real-time monitoring of the motor speed and comparing it with a preset speed threshold, smooth switching of the motor control mode is achieved. Square wave control is used at low speed to improve efficiency, and FOC control is switched to at high speed to improve control accuracy and dynamic response. By collecting system current and system voltage, the motor speed is calculated, and a smooth transition is performed during the switching process to ensure stable operation of the motor under heavy load conditions within the full speed range.

[0087] Please refer to Figure 3 , Figure 3 A structural schematic diagram of a control circuit of a motor control switching method provided by an embodiment of the present invention.

[0088] A control circuit of a motor control switching method, used to implement the motor control switching method, comprising: a power supply module, a current sampling module, a power switch module, a control module, an ADC sampling module and a motor;

[0089] The power supply module is electrically connected to the control module and the power switch module; the control module is electrically connected to the power switch module, the ADC sampling module and the current sampling module; the power switch module is electrically connected to the current sampling module, the ADC sampling module and the motor; the ADC sampling module is electrically connected to the motor;

[0090] The power supply module is used to supply power to the control module and the power switch module; the current sampling module is used to collect the three-phase current of the motor; the power switch module is used to control the motor; the ADC sampling module is used to collect the three-phase voltage of the motor; the control module is used to calculate the motor speed and switch the motor control mode.

[0091] Please refer to Figure 4 , Figure 4 Another structural schematic diagram of a control circuit of a motor control switching method provided by an embodiment of the present invention.

[0092] In this embodiment, the power module further includes a DCDC converter;

[0093] The DCDC converter is electrically connected to the control module and the ADC sampling module.

[0094] In this embodiment, the power switch module includes a three-phase inverter;

[0095] The three-phase inverter includes six MOSFET tubes.

[0096] In this embodiment, the current sampling module includes a first sampling resistor, a second sampling resistor, a first comparator and a second comparator;

[0097] A first end of the first sampling resistor is electrically connected to the power switch module, and a first end of the second sampling resistor is electrically connected to the power switch module;

[0098] The non-inverting input terminal of the first comparator is electrically connected to the power switch module, and the non-inverting input terminal of the second comparator is electrically connected to the power switch module;

[0099] The non-inverting input terminal of the first comparator is electrically connected to the first end of the first sampling resistor, and the non-inverting input terminal of the second comparator is electrically connected to the first end of the second sampling resistor;

[0100] The inverting input terminal of the first comparator is electrically connected to the second end of the first sampling resistor, and the inverting input terminal of the second comparator is electrically connected to the second end of the second sampling resistor.

[0101] In this embodiment, the power supply module supplies power to the control module and the power switch module, wherein the control module includes an MCU processing unit, which includes a PWM module. The control module controls the on and off of the MOSFET through the PWM module, thereby realizing real-time control of the motor.

[0102] In this embodiment, the MUC model used is LKS32MC054DF6Q8.

[0103] In this embodiment, the MCU collects the first component current of the three-phase current of the motor through the first resistor R1 and the first comparator S1, and collects the second component current of the three-phase current of the motor through the second resistor R2 and the second comparator S2, thereby calculating the D-axis current and Q-axis current of the motor to realize the sensorless FOC vector control of the motor.

[0104] In this embodiment, the U-phase current of the motor is collected by the first resistor R1 and the first comparator S1, and the V-phase current of the three-phase current of the motor is collected by the second resistor R2 and the second comparator S2, so as to obtain the first component current I a and the second component current I b The first component current I a and the second component current I b After Clark transformation, I α , I β I α , I β After park transformation, the D-axis current I d , Q axis current I q ;

[0105] In this embodiment, based on the D-axis current I d , Q axis current I q The motor speed Wr is calculated and the real-time position of the motor can be obtained by integrating Wr.

[0106] Please refer to Figure 5 , Figure 5 A non-inductive FOC switching non-inductive square wave current waveform diagram provided in an embodiment of the present invention.

[0107] In this embodiment, under the sensorless FOC control, when the motor speed is less than the threshold speed, the MCU controls the motor to switch to the sensorless square wave control.

[0108] In this embodiment, the D-axis current and Q-axis current of the motor are controlled by sensorless FOC, and the motor speed and position are calculated to achieve precise speed and position control of the motor while reducing cost and complexity.

[0109] In this embodiment, the MCU determines the zero-crossing signal by collecting the back electromotive force of the suspended phase of the motor, and determines the commutation time based on the zero-crossing signal, so as to control the motor to commutate according to the commutation time and the six-step commutation method.

[0110] As a specific example of an embodiment of the present invention, in the inductive square wave control, the power module's power-on commutation mode is: (1) U+V-, (2) U+W-, (3) V+W-, (4) V+U-, (5) W+U-, (6) W+V-.

[0111] In this embodiment, in this power-on commutation mode, when the corresponding phase is energized, the motor zero-crossing signal is judged by detecting the back electromotive force of the suspended phase (unenergized phase), and the motor commutation operation is implemented according to the zero-crossing signal, and the motor running speed is calculated synchronously.

[0112] Please refer to Figure 6 , Figure 6 An inductive square wave switching inductive FOC current waveform diagram provided in an embodiment of the present invention.

[0113] In this embodiment, under the sensorless square wave control, when the motor speed is greater than or equal to the threshold speed, the MCU controls the motor to switch to the sensorless FOC control.

[0114] In this embodiment, the sensorless square wave control method is used at low speed to achieve low-speed and heavy-load starting. When the speed reaches a certain threshold, the sensorless square wave control method is switched to the sensorless FOC control method to achieve high-efficiency and low-noise control.

[0115] In this embodiment, by real-time monitoring of the motor speed and comparing it with a preset speed threshold, smooth switching of the motor control mode is achieved. Square wave control is used at low speed to improve efficiency, and FOC control is switched to at high speed to improve control accuracy and dynamic response. By collecting system current and system voltage, the motor speed is calculated, and a smooth transition is performed during the switching process to ensure stable operation of the motor under heavy load conditions within the full speed range.

[0116] In an embodiment of the present invention, a terminal device is also provided, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, and the processor implements the above-mentioned motor control switching method when executing the computer program.

[0117] In an embodiment of the present invention, a computer-readable storage medium is further provided. The computer-readable storage medium includes a stored computer program. When the computer program is running, the device where the computer-readable storage medium is located is controlled to execute the above-mentioned motor control switching method.

[0118] Exemplarily, the computer program may be divided into one or more modules, one or more modules are stored in a memory and executed by a processor to implement the present invention. One or more modules may be a series of computer program instruction segments capable of implementing specific functions, and the instruction segments are used to describe the execution process of the computer program in a terminal device.

[0119] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, and a cloud server. The terminal device may include, but is not limited to, a processor, a memory, and a display. Those skilled in the art will appreciate that the above components are merely examples of the terminal device and do not constitute a limitation on the terminal device. The terminal device may include more or fewer components than the components, or may combine certain components, or different components. For example, the terminal device may also include input and output devices, network access devices, buses, etc.

[0120] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the terminal device, and uses various interfaces and lines to connect various parts of the entire terminal device.

[0121] The memory can be used to store computer programs and / or modules. The processor implements various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required for a function (such as a sound playback function, a text conversion function, etc.), etc.; the data storage area can store data created according to the use of the mobile phone (such as audio data, text message data, etc.), etc. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0122] Among them, if the module based on the processing of the multi-device access platform is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium, etc. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0123] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A motor control switching method, characterized in that: include: Determine a real-time motor control mode, collect a system current and a system voltage based on the real-time motor control mode, and calculate a motor speed based on the system current and the system voltage; The motor speed is compared with a preset speed threshold, and the motor control mode is switched based on the comparison result and the real-time motor control mode, wherein the motor control mode includes square wave control and FOC control.

2. A motor control switching method as claimed in claim 1, characterized in that: The collecting of system current and system voltage based on the real-time motor control mode, and calculating the motor speed based on the system current and the system voltage, includes: When the real-time motor control mode is FOC control, collecting system current, and calculating the motor speed based on the system current; When the real-time motor control mode is square wave control, the system voltage is collected, and the motor speed is calculated based on the system voltage.

3. A motor control switching method as claimed in claim 2, characterized in that: When the real-time motor control mode is FOC control, collecting the system current and calculating the motor speed based on the system current include: When the real-time motor control mode is FOC control, a first component current and a second component current of the three-phase current of the motor are collected based on a sampling resistor; Performing coordinate transformation on the first component current and the second component current to obtain a D-axis current and a Q-axis current; The motor speed and the motor position are calculated based on the D-axis current, the Q-axis current, the motor resistance and the motor inductance.

4. A motor control switching method as claimed in claim 3, characterized in that: The switching of the motor control mode based on the comparison result and the real-time motor control mode includes: If the motor speed is less than the speed threshold and the real-time motor control mode is FOC control, the motor control mode is switched to square wave control.

5. A motor control switching method as claimed in claim 2, characterized in that: When the real-time motor control mode is square wave control, collecting the system voltage and calculating the motor speed based on the system voltage include: When the real-time motor control mode is square wave control, detecting the back electromotive force of the suspended phase of the motor, and acquiring the motor zero-crossing signal based on the back electromotive force of the suspended phase; The motor is controlled to perform commutation operation based on the motor zero-crossing signal and the six-step commutation control method, and the motor speed is calculated based on the motor zero-crossing signal.

6. A motor control switching method as claimed in claim 5, characterized in that: The switching of the motor control mode based on the comparison result and the real-time motor control mode includes: If the motor speed is greater than or equal to the speed threshold and the real-time motor control mode is square wave control, the motor control mode is switched to FOC control.

7. A control circuit of a motor control switching method, characterized in that: A motor control switching method for implementing any one of claims 1 to 6, comprising: a power supply module, a current sampling module, a power switch module, a control module, an ADC sampling module and a motor; The power supply module is electrically connected to the control module and the power switch module; the control module is electrically connected to the power switch module, the ADC sampling module and the current sampling module; the power switch module is electrically connected to the current sampling module, the ADC sampling module and the motor; the ADC sampling module is electrically connected to the motor; The power supply module is used to supply power to the control module and the power switch module; the current sampling module is used to collect the three-phase current of the motor; the power switch module is used to control the motor; the ADC sampling module is used to collect the three-phase voltage of the motor; the control module is used to calculate the motor speed and switch the motor control mode.

8. The control circuit of the motor control switching method according to claim 7, characterized in that: The power module also includes a DCDC converter; The DCDC converter is electrically connected to the control module and the ADC sampling module.

9. The control circuit of the motor control switching method according to claim 7, characterized in that: The power switch module includes a three-phase inverter; The three-phase inverter includes six MOSFET tubes.

10. The control circuit of the motor control switching method according to claim 7, characterized in that: The current sampling module includes a first sampling resistor, a second sampling resistor, a first comparator and a second comparator; A first end of the first sampling resistor is electrically connected to the power switch module, and a first end of the second sampling resistor is electrically connected to the power switch module; The non-inverting input terminal of the first comparator is electrically connected to the power switch module, and the non-inverting input terminal of the second comparator is electrically connected to the power switch module; The non-inverting input terminal of the first comparator is electrically connected to the first end of the first sampling resistor, and the non-inverting input terminal of the second comparator is electrically connected to the first end of the second sampling resistor; The inverting input terminal of the first comparator is electrically connected to the second end of the first sampling resistor, and the inverting input terminal of the second comparator is electrically connected to the second end of the second sampling resistor.

Images