Starting method and starting device of brushless motor

Abstract

The invention discloses a brushless motor starting method and device, and the method comprises the steps: controlling a power controller to drive a rotor of a brushless motor to rotate to a starting position in response to a received starting signal; controlling a power supply controller to drive a rotor of the brushless motor to rotate through an open-loop control strategy, and detecting a back electromotive force signal on a stator of the brushless motor through a back electromotive force sensor; and determining an estimated rotating speed and an estimated position of the brushless motor according to the back electromotive force signal through a closed-loop control strategy, and controlling a power supply controller to drive the rotating speed of a rotor of the brushless motor to reach a preset target rotating speed according to the estimated rotating speed and the estimated position. The precision of rotating speed control of the brushless motor under the low-rotating-speed working condition is guaranteed, the dependence on a high-precision position sensor is reduced, the system cost is reduced, the dynamic response performance is improved, the special requirement of the starting stage can be met, and efficient dynamic adjustment can be achieved in the operation stage.

Description

Technical Field

[0001] The present invention relates to the technical field of electric motors, in particular to a device for starting an electric motor or an electromechanical converter, and more particularly to a starting method and a starting device for a brushless motor. Background Art

[0002] The control methods of brushless motors include open-loop control and closed-loop control. Usually, a brushless motor is controlled by simply adopting an open-loop control strategy or a simple sampling closed-loop control strategy.

[0003] However, the inventors have discovered that the simple use of an open-loop control strategy relies too much on the position sensor, resulting in the need to use a high-precision position sensor to control the rotation of the brushless motor at high speeds, which results in a high control cost for the brushless motor. In addition, the need to control the speed of the brushless motor based on the signal output of the position sensor results in poor dynamic response performance of the brushless motor.

[0004] At the same time, simply adopting a closed-loop control strategy can easily lead to the problem of low accuracy in low-speed control of the brushless motor due to insufficient feedback strength of the back-electromotive force signal of the brushless motor at low speeds. Summary of the invention

[0005] The purpose of the present invention is to provide a starting method and a starting device for a brushless motor, which are used to solve the problems of high control cost and poor dynamic response performance of the open-loop control strategy in the prior art, and the problem of low accuracy of low-speed control of the closed-loop control strategy.

[0006] To achieve the above object, the present invention provides a method for starting a brushless motor, which is operated in a starting device, wherein the starting device is connected to a power controller, and the power controller is connected to at least one stator in the brushless motor, and the power controller is used to output a starting voltage and a starting current to the stator; The starting device is also connected to a position sensor, which is connected to the rotor in the brushless motor, and is used to detect the rotation angle of the rotor; The starting device is also connected to at least one back electromotive force sensor, one of the back electromotive force sensors is connected to one of the stators, and the back electromotive force sensor is used to detect the back electromotive force on the stator; The starting method comprises: In response to receiving a start signal, the power controller is controlled to drive the rotor of the brushless motor to rotate to a start position; wherein the start signal is used to instruct the rotor of the brushless motor to rotate to a specified speed; and the start position is a starting position at which the rotor starts to rotate; The power controller is controlled by an open-loop control strategy to drive the rotor of the brushless motor to rotate, and the back-electromotive force signal on the stator of the brushless motor is detected by the back-electromotive force sensor; wherein the open-loop control strategy is an operation strategy for controlling the rotation of the rotor of the brushless motor based on a position sensor; the back-electromotive force signal is the induced electromotive force generated in the stator when the rotor rotates and cuts the magnetic flux lines in the stator; The estimated speed and estimated position of the brushless motor are determined according to the back electromotive force signal through a closed-loop control strategy, and the power controller is controlled according to the estimated speed and the estimated position to drive the speed of the rotor of the brushless motor to reach a preset target speed; wherein the closed-loop control strategy is an operating strategy for controlling the rotation of the rotor of the brushless motor based on the back electromotive force; the estimated speed is the rotor rotation speed corresponding to the back electromotive force signal; and the estimated position is the rotor rotation angle corresponding to the back electromotive force signal.

[0007] In the above scheme, controlling the power controller to drive the rotor of the brushless motor to rotate to the starting position includes: Controlling a power supply controller to output a homing voltage to a first phase and a second phase of the brushless motor to rotate the rotor of the motor; wherein the power supply controller is used to output a voltage to a stator of the brushless motor; the first phase is a stator in the brushless motor; and the second phase is a stator in the brushless motor other than the first phase; When the position sensor detects that the rotor rotates to the starting angle, the homing voltage is stopped.

[0008] In the above scheme, the power controller is controlled by an open-loop control strategy to drive the rotor of the brushless motor to rotate, and the back electromotive force signal on the stator of the brushless motor is detected, including: If it is determined that the type of the starting signal is the first type, the power supply controller is controlled to drive the brushless motor through a constant voltage and frequency boost mode, and the back electromotive force signal on at least one stator of the brushless motor is collected through the back electromotive force sensor; wherein the first type is used to indicate that the brushless motor rotates from a standstill to a first specified speed within a first time; the first time is greater than a preset split time; the first specified speed is less than a preset split speed; the constant voltage and frequency boost mode is a driving strategy in which the voltage value of the starting voltage output by the power supply controller to the brushless motor remains unchanged and the voltage frequency gradually increases; the starting voltage is the voltage used by the power supply controller to drive the rotor of the brushless motor to rotate; If it is determined that the type of the starting signal is the second type, the power supply controller is controlled to drive the brushless motor through a constant frequency boost mode, and the back electromotive force signal on at least one stator of the brushless motor is collected through the back electromotive force sensor; wherein the second type is used to indicate that the brushless motor rotates from a standstill to a second specified speed within a second time; the second time is greater than the split time; the second specified speed is greater than or equal to the split speed; the constant frequency boost mode is a driving strategy in which the voltage frequency of the starting voltage output by the power supply controller to the brushless motor remains unchanged and the voltage value gradually increases; If it is determined that the type of the starting signal is the third type, the brushless motor is driven by the frequency-boosting mode, and the back-electromotive force signal on at least one stator of the brushless motor is collected by the back-electromotive force sensor; wherein, the third type is used to indicate that the brushless motor rotates from a standstill to a third specified speed within a third time; the third time is less than or equal to the division time; the third specified speed is greater than or equal to the division speed; the frequency-boosting mode is a driving strategy in which the voltage frequency and voltage value of the starting voltage output by the power controller to the brushless motor are gradually increased.

[0009] In the above scheme, the estimated speed and estimated position of the brushless motor are determined according to the back electromotive force signal through a closed-loop control strategy, including: If the speed of the motor exceeds the preset closed-loop speed, and more than N back-electromotive force zero-crossing signals are detected from at least one of the stators during the preset closed-loop period, the collected back-electromotive force signals are converted into back-electromotive force digital signals; The estimated speed and estimated position of the brushless motor are determined according to the back electromotive force digital signal and the motor parameters of the brushless motor; wherein the motor parameters include: the inductance of the stator in the brushless motor, the resistance of the stator in the brushless motor, the number of pole pairs of the brushless motor, and the rated voltage of the brushless motor.

[0010] In the above scheme, determining the estimated speed and estimated position of the brushless motor according to the back electromotive force digital signal and the motor parameters of the brushless motor includes: Inputting the motor parameters into a preset estimation model to obtain a target model; The target model is called to obtain the estimated rotation speed and the estimated position according to the back electromotive force signal.

[0011] In the above scheme, controlling the power controller to drive the rotor of the brushless motor to reach a preset target speed according to the estimated speed and the estimated position includes: Obtaining the current starting voltage and starting current of each stator in the brushless motor from the power controller; Based on the current starting current of each stator, a first output signal is generated according to the speed difference between the target speed and the estimated speed, and the first output signal is sent to the power controller; wherein the first output signal is used to instruct the power controller to increase or decrease the starting current received by each stator to reduce the speed difference and make the speed of the rotor approach or reach the target speed.

[0012] In the above solution, based on the current starting current of each stator, generating a first output signal according to the speed difference between the estimated speed and the target speed includes: Converting a starting current in at least one of the stators from a three-phase stationary coordinate system to a two-phase stationary coordinate system according to the estimated position to obtain a first DC component and a first quadrature-axis component; According to the speed difference between the target speed and the estimated speed, respectively adjusting the first DC component and the first quadrature-axis component to obtain a first DC adjustment component and a second quadrature-axis adjustment component; The first DC adjustment component and the second quadrature-axis adjustment component are converted from a two-phase stationary coordinate system to a three-phase stationary coordinate system to obtain a first output signal.

[0013] In the above scheme, controlling the power controller to drive the rotor of the brushless motor to reach a preset target speed according to the estimated speed and the estimated position includes: The current flux of the brushless motor is determined according to the current starting voltage and starting current of each stator, and the second output signal is obtained according to the flux difference between the target flux corresponding to the target speed and the current flux, and the torque difference between the target torque corresponding to the target speed and the estimated torque; wherein the estimated torque is the current output torque of the rotor; the second output signal is used to instruct the power supply controller to increase or decrease the voltage vector of the starting voltage received by each stator to reduce the flux difference and the torque difference, and make the torque of the rotor approach or reach the target torque; when the flux difference and the torque difference are respectively zero, the speed of the rotor will reach the target speed.

[0014] In the above solution, the second output signal is obtained according to the flux difference between the target flux corresponding to the target speed and the current flux, and the torque difference between the target torque corresponding to the target speed and the estimated torque, including: Obtaining a target torque corresponding to a target speed, and inputting the target torque into a direct torque controller to obtain a target flux; Controlling the direct torque controller to obtain the instantaneous flux linkage of the brushless motor according to the instantaneous voltage of the stator winding in the brushless motor; Invoking a hysteresis comparator in the direct torque controller to calculate a torque difference between the estimated torque and the target torque, and a flux difference between the instantaneous flux and the target flux; If the hysteresis comparator determines that the torque difference exceeds a preset torque threshold value, and / or the flux difference exceeds a preset flux threshold value, a second output signal is generated according to a preset torque-flux mapping table; wherein the torque-flux mapping table records at least one torque difference value, an indication corresponding to each torque difference value, and a voltage vector corresponding to each torque difference value and each flux difference value.

[0015] To achieve the above object, the present invention further provides a starting device for a brushless motor, wherein the starting device is connected to a power controller, the power controller is connected to at least one stator in the brushless motor, and the power controller is used to output a starting voltage and a starting current to the stator; The starting device is also connected to a position sensor, which is connected to the rotor in the brushless motor, and is used to detect the rotation angle of the rotor; The starting device is also connected to at least one back electromotive force sensor, one of the back electromotive force sensors is connected to one of the stators, and the back electromotive force sensor is used to detect the back electromotive force on the stator; The starting device comprises: A starting module, configured to control the power controller to drive the rotor of the brushless motor to rotate to a starting position in response to receiving a starting signal; wherein the starting signal is used to instruct the rotor of the brushless motor to rotate to a specified speed; and the starting position is a starting position at which the rotor starts to rotate; An open-loop control module, used to control the power controller to drive the rotor of the brushless motor to rotate through an open-loop control strategy, and detect the back-electromotive force signal on the stator of the brushless motor through the back-electromotive force sensor; wherein the open-loop control strategy is an operation strategy for controlling the rotation of the rotor of the brushless motor based on a position sensor; the back-electromotive force signal is the induced electromotive force generated in the stator when the rotor rotates and cuts the magnetic flux lines in the stator; A closed-loop control module is used to determine the estimated speed and estimated position of the brushless motor according to the back-electromotive force signal through a closed-loop control strategy, and control the power controller to drive the speed of the rotor of the brushless motor to reach a preset target speed according to the estimated speed and the estimated position; wherein the closed-loop control strategy is an operating strategy for controlling the rotation of the rotor of the brushless motor based on the back-electromotive force; the estimated speed is the rotor rotation speed corresponding to the back-electromotive force signal; and the estimated position is the rotor rotation angle corresponding to the back-electromotive force signal.

[0016] To achieve the above objectives, the present invention also provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor of the electronic device implements the steps of the above-mentioned brushless motor starting method when executing the computer program.

[0017] To achieve the above objectives, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program stored in the computer-readable storage medium is executed by a processor, the steps of the above-mentioned brushless motor starting method are implemented.

[0018] The present invention provides a starting method and a starting device for a brushless motor, which are used to control the rotation of the brushless motor under low speed conditions through an open-loop control strategy, thereby achieving the technical effect of controlling the rotation speed of the brushless motor based on a position sensor, and ensuring the accuracy of the speed control of the brushless motor under low speed conditions.

[0019] The initial rotation of the rotor generates sufficient back-EMF signals to provide reliable state input. Using back-EMF as the main input for subsequent control reduces the reliance on high-precision position sensors and reduces system costs. Closed-loop control adjusts speed and position in real time based on back-EMF signals to improve dynamic response performance. Speed ​​and position are estimated through back-EMF to ensure that the control signal accurately matches the motor state.

[0020] The combination of open loop and closed loop enables the starting device to meet the special needs of the starting stage and achieve efficient dynamic adjustment during the operation stage. The position and speed estimation through the back-EMF signal can replace the role of traditional sensors and is suitable for brushless motor control scenarios without position sensors.

[0021] Open-loop control is used during the startup phase to avoid additional energy consumption caused by unstable feedback in closed-loop control. Accurate feedback of back-EMF signals can reduce reactive power and improve system efficiency. The open-loop strategy has low sensor dependence and strong fault tolerance during the startup phase; the closed-loop strategy has high operating stability through feedback adjustment. The real-time feedback mechanism of closed-loop control can adapt to different load conditions and ensure that the speed reaches the target value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A flowchart of a method for starting a brushless motor of the present invention; Figure 2 A structural schematic diagram of the connection relationship between a starting device of a brushless motor and a power controller, a brushless motor, a position sensor and a back electromotive force sensor of the present invention; Figure 3 It is a schematic diagram of the hardware structure of the electronic device in the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] Example 1: Please refer to Figure 1 , the present application provides a method for starting a brushless motor, which is operated in a starting device, the starting device is connected to a power controller, the power controller is connected to at least one stator in the brushless motor, and the power controller is used to output a starting voltage and a starting current to the stator; The starting device is also connected to a position sensor, which is connected to the rotor in the brushless motor, and the position sensor is used to detect the rotation angle of the rotor; The starting device is also connected to at least one back electromotive force sensor, one back electromotive force sensor is connected to a stator, and the back electromotive force sensor is used to detect the back electromotive force on the stator; Startup methods include: S1: In response to receiving a start signal, the power supply controller drives the rotor of the brushless motor to rotate to a start position; wherein the start signal is used to instruct the rotor of the brushless motor to rotate to a specified speed; the start position is the starting position where the rotor starts to rotate; S2: Control the power controller to drive the rotor of the brushless motor to rotate through an open-loop control strategy, and detect the back-electromotive force signal on the stator of the brushless motor through a back-electromotive force sensor; wherein the open-loop control strategy is an operation strategy for controlling the rotation of the rotor of the brushless motor based on a position sensor; the back-electromotive force signal is the induced electromotive force generated in the stator when the rotor rotates and cuts the magnetic flux lines in the stator; S3: Determine the estimated speed and estimated position of the brushless motor according to the back electromotive force signal through a closed-loop control strategy, and control the power controller to drive the rotor of the brushless motor to reach a preset target speed according to the estimated speed and estimated position; wherein the closed-loop control strategy is an operating strategy for controlling the rotation of the rotor of the brushless motor based on the back electromotive force; the estimated speed is the rotor rotation speed corresponding to the back electromotive force signal; the estimated position is the rotor rotation angle corresponding to the back electromotive force signal.

[0025] In this example, an open-loop control strategy is used to control the rotation of the brushless motor under low speed conditions, achieving the technical effect of controlling the rotation speed of the brushless motor based on a position sensor, and ensuring the accuracy of the speed control of the brushless motor under low speed conditions.

[0026] The initial rotation of the rotor generates sufficient back-EMF signals to provide reliable state input. Using back-EMF as the main input for subsequent control reduces the reliance on high-precision position sensors and reduces system costs. Closed-loop control adjusts speed and position in real time based on back-EMF signals to improve dynamic response performance. Speed ​​and position are estimated through back-EMF to ensure that the control signal accurately matches the motor state.

[0027] The combination of open loop and closed loop enables the starting device to meet the special needs of the starting stage and achieve efficient dynamic adjustment during the operation stage. The position and speed estimation through the back-EMF signal can replace the role of traditional sensors and is suitable for brushless motor control scenarios without position sensors.

[0028] Open-loop control is used during the startup phase to avoid additional energy consumption caused by unstable feedback in closed-loop control. Accurate feedback of back-EMF signals can reduce reactive power and improve system efficiency. The open-loop strategy has low sensor dependence and strong fault tolerance during the startup phase; the closed-loop strategy has high operating stability through feedback adjustment. The real-time feedback mechanism of closed-loop control can adapt to different load conditions and ensure that the speed reaches the target value.

[0029] In a preferred embodiment, controlling the power supply controller to drive the rotor of the brushless motor to rotate to a starting position includes: The power supply controller is controlled to output a homing voltage to the first phase and the second phase of the brushless motor to rotate the rotor of the motor; wherein the power supply controller is used to output a voltage to the stator of the brushless motor; the first phase is a stator in the brushless motor; the second phase is a stator in the brushless motor except the first phase; When the position sensor detects that the rotor has rotated to the starting angle, the return voltage is stopped.

[0030] In this example, during the starting phase, the power controller outputs a homing voltage to the first and second phases of the brushless motor. The homing voltage is intended to cause the rotor of the motor to start rotating from a stationary state. This is usually done by applying a voltage to a specific stator winding, thereby generating a rotating magnetic field that interacts with the permanent magnets of the motor, causing the rotor to start rotating.

[0031] The position sensor detects whether the rotor has rotated to a specific starting angle, which is the minimum angle required for the motor to run stably. Once it detects that the rotor has rotated to the starting angle, the power controller stops outputting the homing voltage to prevent the motor from being further excited. The main purpose of this control process is to achieve smooth starting of the brushless motor. By accurately controlling the voltage and current, it can be ensured that the motor will not be subjected to excessive shock during starting, thereby extending the service life of the motor.

[0032] In a preferred embodiment, the power controller is controlled by an open-loop control strategy to drive the rotor of the brushless motor to rotate, and the back electromotive force signal on the stator of the brushless motor is detected, including: If it is determined that the type of the starting signal is the first type, the power supply controller is controlled to drive the brushless motor through the constant voltage and frequency boost mode, and the back electromotive force signal on at least one stator of the brushless motor is collected through the back electromotive force sensor; wherein the first type is used to indicate that the brushless motor rotates from a standstill to a first specified speed within a first time; the first time is greater than a preset split time; the first specified speed is less than a preset split speed; the constant voltage and frequency boost mode is a driving strategy in which the voltage value of the starting voltage output by the power supply controller to the brushless motor remains unchanged and the voltage frequency gradually increases; the starting voltage is the voltage used by the power supply controller to drive the rotor of the brushless motor to rotate; If it is determined that the type of the starting signal is the second type, the power supply controller is controlled to drive the brushless motor through the constant frequency boost mode, and the back electromotive force signal on at least one stator of the brushless motor is collected through the back electromotive force sensor; wherein the second type is used to indicate that the brushless motor rotates from a stationary state to a second specified speed within a second time; the second time is greater than the split time; the second specified speed is greater than or equal to the split speed; the constant frequency boost mode is a driving strategy in which the voltage frequency of the starting voltage output by the power supply controller to the brushless motor remains unchanged and the voltage value gradually increases; If the type of the starting signal is determined to be the third type, the brushless motor is driven through the frequency-boosting mode, and the back-electromotive force signal on at least one stator of the brushless motor is collected through the back-electromotive force sensor; wherein the third type is used to indicate that the brushless motor rotates from a standstill to a third specified speed within a third time; the third time is less than or equal to the split time; the third specified speed is greater than or equal to the split speed; the frequency-boosting mode is a driving strategy in which the voltage frequency and voltage value of the starting voltage output by the power controller to the brushless motor are gradually increased.

[0033] In this example, when the type of the start signal is the first type, it indicates that the brushless motor needs to rotate from a standstill to a first specified speed (less than the preset split speed) within a first time (greater than the preset split time). The voltage value of the starting voltage output by the power controller to the brushless motor remains unchanged, while the voltage frequency gradually increases. This strategy helps to provide a stable voltage at the beginning of the motor start, while gradually increasing the frequency to gradually accelerate the motor. During the motor start-up phase, the constant voltage can ensure that the motor obtains a stable driving force, and the gradual increase in frequency can smoothly accelerate the motor to the specified speed.

[0034] When the type of the start signal is the second type, it indicates that the brushless motor needs to rotate from a standstill to a second specified speed (greater than or equal to the split speed) within a second time (greater than the split time). The voltage frequency of the starting voltage output by the power controller to the brushless motor remains unchanged, while the voltage value gradually increases. This strategy is suitable for situations where the motor needs to reach a higher speed in a short time. While keeping the frequency unchanged, gradually increasing the voltage can ensure that the motor obtains sufficient driving force during the acceleration process, so as to quickly reach the specified speed.

[0035] When the type of the start signal is the third type, it indicates that the brushless motor needs to rotate from a standstill to a third specified speed (greater than or equal to the split speed) within a third time (less than or equal to the split time). The voltage frequency and voltage value of the starting voltage output by the power controller to the brushless motor are gradually increased. This strategy combines the advantages of the first two modes and is suitable for situations where the motor needs to accelerate quickly to a higher speed in a short time. Increasing the voltage and frequency at the same time can ensure that the motor obtains the maximum driving force during the starting phase, so as to quickly reach the specified speed.

[0036] Therefore, by selecting the appropriate control strategy according to the different starting signal types, the speed and position of the brushless motor can be precisely controlled. This helps to improve the operating efficiency and stability of the motor. By adjusting the voltage and frequency, it can adapt to different load conditions and ensure that the motor can operate stably under different loads. Accurate control strategies can reduce noise and vibration during the starting and operation of the motor, thereby improving user comfort and satisfaction.

[0037] In a preferred embodiment, the estimated speed and estimated position of the brushless motor are determined according to the back electromotive force signal by a closed-loop control strategy, including: If the speed of the motor exceeds the preset closed-loop speed, and more than N back-electromotive force zero-crossing signals are detected from at least one stator during the preset closed-loop period, the collected back-electromotive force signals are converted into back-electromotive force digital signals; The estimated speed and estimated position of the brushless motor are determined according to the back electromotive force digital signal and the motor parameters of the brushless motor; wherein the motor parameters include: the inductance of the stator in the brushless motor, the resistance of the stator in the brushless motor, the number of pole pairs of the brushless motor, and the rated voltage of the brushless motor.

[0038] In this example, when the motor speed exceeds the preset closed-loop speed, the system starts to collect back-EMF signals on the stator. These signals are voltage signals induced in the stator winding by the magnetic field generated by the permanent magnet during the operation of the motor.

[0039] During the preset closed-loop period, the system continuously collects these signals and detects whether they contain more than N back-EMF zero-crossing signals. The zero-crossing signal refers to the signal generated when the back-EMF signal changes from positive to negative or from negative to positive, which marks a specific point in the motor rotor position. Once more than N back-EMF zero-crossing signals are detected, it means that the motor is running stably and the back-EMF signal is clear enough for subsequent estimation and control. The detected back-EMF signal is converted into a digital signal for subsequent digital signal processing and estimation. This is usually achieved through an analog-to-digital converter (ADC).

[0040] In this embodiment, back electromotive force: Back electromotive force is an electrical signal generated when the brushless motor is running, which is proportional to the motor speed. By measuring the back electromotive force signal, the motor speed information can be obtained.

[0041] Inductance: Inductance refers to the ability of an inductor to resist current changes. The size of the inductance affects the starting performance, stability and efficiency of the motor.

[0042] Resistance: The internal resistance of the motor affects the flow of current, which in turn affects the speed and efficiency of the motor.

[0043] Pole pairs: Pole pairs are an important factor affecting motor speed. Generally, as the number of pole pairs decreases, the motor speed increases accordingly; conversely, as the number of pole pairs increases, the speed decreases.

[0044] Rated voltage: Provides the energy required for the motor to operate. Increasing the voltage can increase the motor speed, but it must be operated within the rated range to avoid damaging the motor.

[0045] In a preferred embodiment, determining the estimated speed and estimated position of the brushless motor according to the back electromotive force digital signal and the motor parameters of the brushless motor includes: Input the motor parameters into the preset estimation model to obtain the target model; The target model is called to obtain the estimated speed and estimated position according to the back electromotive force signal.

[0046] In this example, motor parameters (such as winding resistance, winding inductance, back electromotive force constant, etc.) are important components of the target model. By inputting these parameters into the preset estimation model, a state estimation model specifically for the motor is generated.

[0047] The input parameters include: winding resistance, winding inductance, back EMF constant, pole pair number, motor inertia and damping coefficient. Generate the state equation of the target model: The state equation of the target model is usually derived from the dynamic and electromagnetic characteristics of the motor.

[0048] Back EMF is an important reference signal for estimating the speed and position of a brushless motor, which can be obtained indirectly through the voltage and current measurement of the motor. The back EMF signal is used in combination with an extended Kalman filter or other algorithms to estimate the speed and position of the motor. The estimated speed and estimated position are obtained based on the real-time operation of the target model. The accuracy of the estimated speed and estimated position calculation is ensured.

[0049] Optionally, the motor parameters are input into a preset estimation model to obtain a target model, including: Enter the motor parameters into the preset phase-locked loop model to adjust the phase-locked loop parameters of the phase-locked loop module and convert the phase-locked loop model into a target model; the phase-locked loop parameters include: the gain of the phase detector, the cutoff frequency of the low-pass filter and the gain of the voltage-controlled oscillator; or The motor parameters are input into the state equation of the filtering algorithm model, and the filtering algorithm model is trained to obtain the target model.

[0050] Optionally, the target model is called to obtain the estimated speed and estimated position according to the back electromotive force signal, including: The back-electromotive force digital signal is used as the input signal of the phase-locked loop module.

[0051] The phase-locked loop module is started, and the phase-locked loop module tracks the frequency and phase of the input signal and continuously adjusts the frequency of the voltage-controlled oscillator of the phase-locked loop module until the frequency and phase of the output signal of the voltage-controlled oscillator, and the frequency difference and phase difference between the frequency and phase of the input signal are respectively lower than the preset frequency threshold and phase threshold.

[0052] Extracting the output frequency of the voltage signal of the voltage-controlled oscillator of the phase-locked loop module; The estimated speed of the brushless motor is calculated based on the output frequency of the voltage-controlled oscillator and the number of pole pairs of the brushless motor.

[0053] The estimated rotation speed is integrated to obtain the estimated position of the brushless motor.

[0054] In this example, the phase-locked loop is a negative feedback starting device that uses the voltage generated by phase synchronization to tune the voltage-controlled oscillator (VCO) to generate the target frequency. It mainly consists of three parts: phase detector (PD), low-pass filter (LF) and voltage-controlled oscillator (VCO).

[0055] Phase detector: used to detect the phase difference between the input signal (back electromotive force digital signal) and the output signal (voltage signal of the voltage-controlled oscillator), and convert this phase difference into a voltage signal output.

[0056] Low-pass filter: used to filter out noise and interference components in the phase detector output signal to form the control voltage of the voltage-controlled oscillator.

[0057] Voltage-controlled oscillator: adjusts the frequency and phase of its output signal according to the control voltage to reduce the phase difference with the input signal.

[0058] The parameters of the phase-locked loop are adjusted according to the motor parameters of the brushless motor to ensure that it can accurately track the phase of the back-EMF signal.

[0059] The pre-processed back-EMF digital signal is used as the input signal of the phase-locked loop. The phase-locked loop starts working, and the phase detector detects the phase difference between the input signal and the output signal of the voltage-controlled oscillator, and outputs the corresponding voltage signal. This voltage signal is filtered by a low-pass filter to form the control voltage of the voltage-controlled oscillator. The voltage-controlled oscillator adjusts the frequency and phase of its output signal according to the control voltage to reduce the phase difference with the input signal. This process is repeated until the phase-locked loop reaches a stable state, that is, the phase difference between the input signal and the output signal remains in a very small range.

[0060] In this example, after the phase-locked loop reaches a stable state, the speed of the brushless motor can be estimated by measuring the frequency of the voltage-controlled oscillator output signal. Since the output signal of the phase-locked loop is synchronized with the phase of the input signal (back-EMF signal), the frequency of the output signal can accurately reflect the speed of the brushless motor. Among them, estimated speed = (voltage-controlled oscillator output frequency / number of pole pairs) * (60 / mechanical cycle corresponding to the number of motor poles). The mechanical cycle corresponding to the number of motor poles refers to the number of electrical cycles required for the brushless motor to complete a full rotation multiplied by the time of each electrical cycle. However, in actual applications, since the back-EMF signal is proportional to the motor speed, the speed can usually be estimated directly by the voltage-controlled oscillator output frequency and the number of pole pairs without considering the mechanical cycle.

[0061] After obtaining an accurate estimated speed value, an integral operation may be performed on it to obtain an estimated position value of the rotor of the brushless motor. In this embodiment, the estimated position may be obtained by a discrete integral method or a continuous integral method.

[0062] Discrete integration method: Since the speed estimate is usually a sampled value at a discrete time point, the discrete integration method can be used to calculate the position. The basic idea of ​​the discrete integration method is to accumulate the speed estimate in each sampling period to obtain the cumulative value of the position. The specific calculation process is: at each sampling time point ti, obtain the corresponding speed estimate ωi, and then calculate the position increment Δθi=ωi×Δt in this time period, where Δt is the sampling period. Finally, all position increments are accumulated to obtain the total position θ of the rotor.

[0063] Continuous integration method: If the speed estimate is a continuously changing function (for example, a continuous time curve of the speed is obtained in some way), the continuous integration method can be used to calculate the position. The basic idea of ​​the continuous integration method is to integrate the speed function to obtain the position function. The specific calculation process is: integrate the speed function ω(t) to obtain the position function θ(t)=∫t0tω(τ)dτ, where t0 is the initial time point and t is the current time point.

[0064] Optionally, the motor parameters are input into the state equation of the filter algorithm model, and the filter algorithm model is trained to obtain a target model, including: Enter the motor parameters into the state equation of the filtering algorithm model to obtain the target state equation; Starting the training motor and collecting the training back electromotive force of the training motor; The filtering algorithm model is called to predict the speed of the training motor according to the target state equation, the training starting voltage, the training starting current, and the training back electromotive force of the training motor to obtain the training estimated speed and the training estimated position; Using a training position sensor to detect the speed and position of the training motor, and obtaining a training observation speed and a training observation position; According to the training speed difference between the training acquisition speed and the training observation speed, the first covariance matrix in the filtering algorithm model is adjusted to obtain a first mature matrix; wherein the first mature matrix is ​​used to make the difference between the training estimated speed obtained according to the target state equation and the training observed speed within a preset training speed threshold range; According to the training position difference between the training acquisition position and the training observation position, the second covariance matrix in the filtering algorithm model is adjusted to obtain a second mature matrix; wherein the second mature matrix is ​​used to make the difference between the training estimated position obtained according to the target state equation and the training observation position within a preset training position threshold range; The filtering algorithm model having the first mature matrix and the second mature matrix is ​​used as a target model corresponding to the motor parameters.

[0065] In this example, the motor parameters include: phase resistance, phase inductance, back electromotive force constant, number of pole pairs, starting voltage and starting current.

[0066] The extended Kalman filter is used as the filtering algorithm model. The Kalman filter (KF) is a recursive estimation algorithm used for state estimation of linear systems. Its basic idea is to combine the system's prediction model and actual measurement data, and use the weighted average method to optimize the estimation result. The state equation is a mathematical model used to predict the speed of a brushless motor based on motor parameters. The first covariance matrix describes the relationship between the training estimated speed generated by the target state equation and the training observed speed; the second covariance matrix describes the relationship between the training estimated position generated by the target state equation and the training observed position.

[0067] Optionally, the target model is called to obtain the estimated speed and estimated position according to the back electromotive force signal, including: The starting voltage and starting current of the brushless motor are collected from the power controller, and the starting voltage and starting current are input into the state equation of the target model; The target model is called to generate an estimated speed and an estimated position according to the back electromotive force signal.

[0068] In a preferred embodiment, controlling the power controller to drive the rotor of the brushless motor to reach a preset target speed according to the estimated speed and the estimated position includes: Obtain the current starting voltage and starting current of each stator in the brushless motor from the power controller; Based on the current starting current of each stator, a first output signal is generated according to the speed difference between the target speed and the estimated speed, and the first output signal is sent to the power controller; wherein the first output signal is used to instruct the power controller to increase or decrease the starting current received by each stator to reduce the speed difference and make the rotor speed approach or reach the target speed.

[0069] Specifically, if the speed difference is a positive value, the starting current received by each stator is increased; if the speed difference is a negative value, the starting current received by each stator is reduced.

[0070] In this example, an adjustment signal is generated based on the difference between the real-time estimated speed and the target speed to quickly compensate for the speed deviation. By accurately adjusting the starting current, the speed fluctuation is reduced, making the rotor run more smoothly.

[0071] By controlling the current input of the power controller in real time, it directly acts on the stator winding to improve the response speed of speed regulation. The rapid change of current can affect the motor flux and electromagnetic torque more timely, thereby accelerating the system response.

[0072] Accurately match the motor's required current to avoid energy waste caused by over- or under-powering. By adjusting the starting current, the motor can run in the efficient working range, reducing the total power consumption of the system.

[0073] Adjusting the stator starting current based on real-time speed feedback can effectively cope with load changes. Even under complex working conditions (such as sudden load changes or rapid changes in target speed), the starting device can still maintain stable operation.

[0074] Precise current regulation avoids mechanical vibration and wear caused by speed fluctuations, reduces mechanical stress, and reduces the wear rate of key components (such as bearings, gears, etc.).

[0075] The solution is based on a closed-loop control architecture and uses the speed difference to generate a signal, which can flexibly adapt to various operating modes. It can be combined with other control technologies (such as direct torque control or space vector modulation) to further improve performance.

[0076] Speed ​​control is achieved by adjusting the starting current, reducing the need for additional speed controllers or complex hardware. A single algorithm can achieve coordinated control of current and speed, simplifying the design of the motor drive system.

[0077] Specifically, according to the speed difference Δω, a control signal for adjusting the starting current is generated: First output signal = KpΔω+Ki∫Δω dt+Kdd(Δω) / dt Kp: Proportional gain, determines the speed and sensitivity of response.

[0078] Ki: Integral gain, eliminates steady-state error.

[0079] Kd: differential gain, predicts the error change trend.

[0080] The first output signal is sent to the power controller to adjust the starting current received by each stator: If Δω>0: it is necessary to increase the starting current IstartI, thereby increasing the motor torque and acceleration, so that the speed is close to the target value. If Δω<0: it is necessary to reduce the starting current IstartI, thereby reducing the torque and deceleration, so that the speed is close to the target value.

[0081] The power controller implements current regulation using the following formula: Vnew=RsInew+Ls×dInew / dt +e; where: Vnew: regulated stator voltage; Inew: regulated starting current; Rs: stator winding resistance; Ls: stator winding inductance; e: represents an external electromotive force, which is the force that drives the current to flow in the power controller, and the electromotive force comes from the battery connected to the power controller.

[0082] In a preferred embodiment, based on the current starting current of each stator, generating a first output signal according to the speed difference between the estimated speed and the target speed includes: Converting a starting current in at least one stator from a three-phase stationary coordinate system to a two-phase stationary coordinate system according to the estimated position to obtain a first DC component and a first quadrature-axis component; According to the speed difference between the target speed and the estimated speed, respectively adjusting the first DC component and the first quadrature-axis component to obtain a first DC adjustment component and a second quadrature-axis adjustment component; The first DC adjustment component and the second quadrature-axis adjustment component are converted from a two-phase stationary coordinate system to a three-phase stationary coordinate system to obtain a first output signal.

[0083] In this step, the current phase relationship in the three-phase stationary coordinate system is complex, and it is difficult to achieve precise regulation by directly controlling the three-phase current. After converting it to a two-phase stationary coordinate system, the control becomes processing two orthogonal components (DC component and quadrature axis component, and the model is more intuitive. In the two-phase stationary coordinate system, the DC component mainly affects the torque, and the quadrature axis component mainly affects the magnetic field. The two do not interfere with each other, which facilitates independent optimization of the control strategy.

[0084] By adjusting the DC component and the quadrature axis component separately, the speed and position can be controlled more accurately without being affected by the complex current interaction of the three phases. The converted components are easy to filter, reducing the interference of high-frequency noise on the control and improving the matching degree between the estimated speed and the target speed.

[0085] Mathematical processing in a two-phase stationary coordinate system is simpler than in a three-phase system. For example, scalars can be used instead of vector calculations, reducing the computational complexity of the control algorithm. For systems with high real-time requirements (such as motor servo control), reducing the computational burden can speed up response and improve system performance.

[0086] In the two-phase coordinate system, a controller (such as PI or PID controller) can be easily added to achieve dynamic adjustment of the target speed and actual speed. The two-phase coordinate system is easier to combine with advanced algorithms such as extended Kalman filter (EKF) or model predictive control (MPC) to further improve system robustness and control performance.

[0087] By adjusting the DC component and the quadrature axis component, the torque output efficiency can be maximized while reducing the ineffective component of the stator current. Reducing the reactive power in the current component reduces motor losses, thereby improving energy efficiency. The system can respond more quickly to speed or load changes, avoiding torque pulsation or instability that may occur in traditional methods.

[0088] In a preferred embodiment, controlling the power controller to drive the rotor of the brushless motor to reach a preset target speed according to the estimated speed and the estimated position includes: The current flux of the brushless motor is determined according to the current starting voltage and starting current of each stator, and the second output signal is obtained according to the flux difference between the target flux corresponding to the target speed and the current flux, and the torque difference between the target torque corresponding to the target speed and the estimated torque; wherein the estimated torque is the current output torque of the rotor; the second output signal is used to instruct the power supply controller to increase or decrease the voltage vector of the starting voltage received by each stator to reduce the flux difference and the torque difference, and make the torque of the rotor approach or reach the target torque; when the flux difference and the torque difference are respectively zero, the speed of the rotor will reach the target speed.

[0089] In this example, by calculating the difference between the current flux and the target flux in real time, the flux of the motor can be dynamically adjusted to keep it within the ideal range. Optimizing the flux can avoid magnetic field saturation of the motor winding and improve the stability and efficiency of the system. Accurately controlling the flux can reduce the iron loss and eddy current loss during motor operation and improve the overall efficiency of the motor.

[0090] By comparing the difference between the target torque and the current estimated torque and adjusting the voltage vector in real time, the impact of load changes on torque can be quickly compensated. The combined regulation of flux and torque can effectively reduce torque pulsation and improve torque output stability. Accurate torque control helps the motor maintain stable operation under high load conditions.

[0091] By adjusting the voltage vector of the starting voltage, it can quickly respond to changes in flux and torque. This control strategy can shorten the response time of the motor when the speed or load changes and enhance the dynamic performance.

[0092] Accurate flux control can reduce the generation of reactive components, thereby improving energy efficiency. By adjusting the voltage vector to match the target flux and target torque, it can ensure that the motor outputs the required torque with minimal energy consumption.

[0093] Real-time adjustment of flux and torque makes the system more robust to load disturbances and supply voltage fluctuations. Brushless motors have nonlinear characteristics. Precise flux and torque control can alleviate the impact of nonlinearity on control performance. Space vector modulation (SVPWM): Voltage vector regulation combined with space vector modulation can achieve high-performance voltage regulation. Model predictive control (MPC): Real-time calculation of flux and torque provides accurate state information for advanced control strategies, which helps to further improve control accuracy.

[0094] Specifically, if the flux difference is a positive value, the voltage vector of the starting voltage received by each stator is increased; if the flux difference is a negative value, the voltage vector of the starting voltage received by each stator is reduced; if the torque difference is a positive value, the voltage vector of the starting voltage received by each stator is increased; if the torque difference is a negative value, the voltage vector of the starting voltage received by each stator is reduced.

[0095] In this example, the space vector modulation method is used to adjust the amplitude and angle of the stator voltage vector: According to the absolute size of the flux difference and torque difference, the voltage vector increment or decrement is determined: Vadjust=Kψ⋅|Δψ|+KT⋅|ΔT|; where Vadjust indicates voltage vector increment or decrement.

[0096] Kψ is the flux gain factor. Magnetic flux is a physical quantity that describes the interaction between a magnetic field and a conductor, and is particularly important in motors. The gain factor Kψ indicates how much the flux change affects the required adjustment voltage.

[0097] Δψ represents the change in flux. In motor control, the change in flux may be caused by a change in current, a change in magnetic field, or a change in motor parameters. Δψ is the absolute value of the change in flux, meaning that whether the flux increases or decreases, its absolute value is taken into account.

[0098] KT is the gain factor of torque. Torque is a physical quantity that describes the rotational effect of force on a rotating object. In motors, it is used to describe the rotational force generated by the motor. The gain factor KT indicates the degree of influence of torque changes on the required adjustment voltage.

[0099] ΔT represents the change in torque. In motor control, the change in torque may be caused by a change in load, a change in motor speed, or a change in motor parameters. ΔT is the absolute value of the change in torque, which also means that whether the torque increases or decreases, its absolute value will be taken into account.

[0100] The direction of vector rotation is determined according to the direction of the difference, optimizing the combined effect of magnetic flux and torque.

[0101] In the two-phase stationary coordinate system, the direct-axis component Vd and the quadrature-axis component Vq of the voltage vector are adjusted respectively: Direct-axis component Vd: related to the flux, increase or decrease to adjust the flux. Quadrature-axis component Vq: related to the torque, increase or decrease to adjust the torque.

[0102] In a preferred embodiment, the second output signal is obtained according to the flux difference between the target flux corresponding to the target speed and the current flux, and the torque difference between the target torque corresponding to the target speed and the estimated torque, including: Obtaining a target torque corresponding to a target speed, and inputting the target torque into a direct torque controller to obtain a target flux; The direct torque controller is controlled to obtain the instantaneous flux linkage of the brushless motor according to the instantaneous voltage of the stator winding in the brushless motor; The hysteresis comparator in the direct torque controller is called to calculate the torque difference between the estimated torque and the target torque, and the flux difference between the instantaneous flux and the target flux; If the hysteresis comparator determines that the torque difference exceeds a preset torque threshold value, and / or the flux difference exceeds a preset flux threshold value, a second output signal is generated according to a preset torque-flux mapping table; wherein the torque-flux mapping table records at least one torque difference value, an indication corresponding to each torque difference value, and a voltage vector corresponding to each torque difference value and each flux difference value.

[0103] In this example, the target torque is determined by a motor controller or an external system according to the target speed and load characteristics, and the target torque is input into a direct torque controller (DTC). The corresponding target flux is calculated by a preset torque-flux relationship or a motor characteristic model.

[0104] According to the instantaneous voltage and current of the stator winding, the instantaneous flux ψ of the brushless motor is calculated using the flux equation: ψ=∫(Vs−RsIs)dt Where: Vs: stator winding instantaneous voltage; Rs: stator winding resistance; Is: stator winding instantaneous current.

[0105] Using the electromagnetic relationship of the motor, the estimated torque T is calculated: T=k(ψdIq−ψqId); where: ψd, ψq: direct-axis and quadrature-axis flux components; Id, Iq: direct-axis and quadrature-axis current components; k: proportional coefficient, which is related to the motor structure.

[0106] The mapping table records the following contents according to the preset motor model or experimental data: the flux adjustment value corresponding to different torque differences, the voltage vector corresponding to the combination of torque difference and flux difference.

[0107] The mapping table is searched according to the torque difference and flux difference to generate a suitable voltage vector. Based on the voltage vector obtained from the mapping table, the inverter is controlled to output the corresponding stator voltage signal to adjust the motor state. The adjusted voltage vector is applied to the stator winding. New flux and torque values ​​are collected in real time, and the above process is repeated until the difference is within the preset threshold range.

[0108] The hysteresis comparator acts directly on the difference between flux linkage and torque, and can respond quickly to state changes. The nonlinear mapping of difference and voltage vector is realized through the mapping table to improve the control accuracy. It is suitable for dynamically changing load and speed requirements. The voltage vector is optimized and adjusted to reduce reactive power loss.

[0109] Example 2: Please refer to Figure 2 , the present application provides a starting device for a brushless motor, the starting device 21 is connected to a power controller 22, the power controller 22 is connected to at least one stator in the brushless motor 23, and the power controller 22 is used to output a starting voltage and a starting current to the stator; The starting device 21 is also connected to a position sensor 24, which is connected to the rotor in the brushless motor 23. The position sensor 24 is used to detect the rotation angle of the rotor. The starter 21 is also connected to at least one back electromotive force sensor 25, one back electromotive force sensor 25 is connected to a stator, and the back electromotive force sensor 25 is used to detect the back electromotive force on the stator; The starting device 21 comprises: The starting module 211 is used to control the power supply controller 22 to drive the rotor of the brushless motor 23 to rotate to the starting position in response to receiving the starting signal; wherein the starting signal is used to instruct the rotor of the brushless motor 23 to rotate to a specified speed; the starting position is the starting position where the rotor starts to rotate; The open-loop control module 212 is used to control the power supply controller 22 to drive the rotor of the brushless motor 23 to rotate through an open-loop control strategy, and detect the back electromotive force signal on the stator of the brushless motor 23 through the back electromotive force sensor 25; wherein the open-loop control strategy is an operation strategy for controlling the rotation of the rotor of the brushless motor 23 based on the position sensor 24; the back electromotive force signal is the induced electromotive force generated in the stator when the rotor rotates and cuts the magnetic flux lines in the stator; The closed-loop control module 213 is used to determine the estimated speed and estimated position of the brushless motor 23 according to the back electromotive force signal through a closed-loop control strategy, and control the power supply controller 22 to drive the rotor of the brushless motor 23 to reach a preset target speed according to the estimated speed and estimated position; wherein the closed-loop control strategy is an operating strategy for controlling the rotation of the rotor of the brushless motor 23 based on the back electromotive force; the estimated speed is the rotor rotation speed corresponding to the back electromotive force signal; and the estimated position is the rotor rotation angle corresponding to the back electromotive force signal.

[0110] Embodiment 3: To achieve the above-mentioned purpose, the present invention further provides an electronic device 3. The components of the brushless motor starting device of Embodiment 3 can be dispersed in different electronic devices. The electronic device 3 can be a smart phone, tablet computer, laptop computer, desktop computer, rack server, blade server, tower server or cabinet server (including independent server, or server cluster composed of multiple application servers) that executes the program. The electronic device of this embodiment includes at least but is not limited to: a memory 31 and a processor 32 that can be interconnected through a system bus, such as Figure 3 It should be pointed out that Figure 3 Only an electronic device with components is shown, but it should be understood that implementing all of the components shown is not a requirement, and more or fewer components may alternatively be implemented.

[0111] In this embodiment, the memory 31 (i.e., a readable storage medium) includes a flash memory, a hard disk, a multimedia card, a card-type memory (e.g., an SD or DX memory, etc.), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a magnetic disk, an optical disk, etc. In some embodiments, the memory 31 may be an internal storage unit of an electronic device, such as a hard disk or a memory of the electronic device. In other embodiments, the memory 31 may also be an external storage device of the electronic device, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device. Of course, the memory 31 may also include both an internal storage unit of the electronic device and its external storage device. In this embodiment, the memory 31 is generally used to store an operating system and various application software installed in the electronic device, such as the program code of the starting device of the brushless motor in the third embodiment, etc. In addition, the memory 31 may also be used to temporarily store various data that have been output or are to be output.

[0112] In some embodiments, the processor 32 may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chips. The processor 32 is generally used to control the overall operation of the electronic device. In this embodiment, the processor 32 is used to run the program code stored in the memory 31 or process data, such as running the starting device of the brushless motor to implement the starting method of the brushless motor of the first embodiment and the second embodiment.

[0113] Embodiment 4: To achieve the above-mentioned purpose, the present invention also provides a computer-readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory (e.g., an SD or DX memory, etc.), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a disk, an optical disk, a server, an App application store, etc., on which a computer program is stored, and the program realizes corresponding functions when executed by the processor 32. The computer-readable storage medium of this embodiment is used to store a computer program for realizing the starting method of a brushless motor, and when executed by the processor 32, the starting method of the brushless motor of Embodiments 1 and 2 is realized.

[0114] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0115] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method.

[0116] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for starting a brushless motor, characterized in that: Running in a starting device, the starting device is connected to a power controller, the power controller is connected to at least one stator in a brushless motor, and the power controller is used to output a starting voltage and a starting current to the stator; The starting device is also connected to a position sensor, which is connected to the rotor in the brushless motor, and is used to detect the rotation angle of the rotor; The starting device is also connected to at least one back electromotive force sensor, one of the back electromotive force sensors is connected to one of the stators, and the back electromotive force sensor is used to detect the back electromotive force on the stator; The starting method comprises: In response to receiving a start signal, the power controller is controlled to drive the rotor of the brushless motor to rotate to a start position; wherein the start signal is used to instruct the rotor of the brushless motor to rotate to a specified speed; and the start position is a starting position at which the rotor starts to rotate; The power controller is controlled by an open-loop control strategy to drive the rotor of the brushless motor to rotate, and the back-electromotive force signal on the stator of the brushless motor is detected by the back-electromotive force sensor; wherein the open-loop control strategy is an operation strategy for controlling the rotation of the rotor of the brushless motor based on a position sensor; the back-electromotive force signal is the induced electromotive force generated in the stator when the rotor rotates and cuts the magnetic flux lines in the stator; The estimated speed and estimated position of the brushless motor are determined according to the back electromotive force signal through a closed-loop control strategy, and the power controller is controlled according to the estimated speed and the estimated position to drive the speed of the rotor of the brushless motor to reach a preset target speed; wherein the closed-loop control strategy is an operating strategy for controlling the rotation of the rotor of the brushless motor based on the back electromotive force; the estimated speed is the rotor rotation speed corresponding to the back electromotive force signal; and the estimated position is the rotor rotation angle corresponding to the back electromotive force signal.

2. The starting method according to claim 1, characterized in that: Controlling the power controller to drive the rotor of the brushless motor to rotate to a starting position includes: Controlling a power supply controller to output a homing voltage to a first phase and a second phase of the brushless motor to rotate the rotor of the motor; wherein the power supply controller is used to output a voltage to a stator of the brushless motor; the first phase is a stator in the brushless motor; and the second phase is a stator in the brushless motor other than the first phase; When the position sensor detects that the rotor rotates to the starting angle, the homing voltage is stopped.

3. The starting method according to claim 1, characterized in that: The power controller is controlled by an open-loop control strategy to drive the rotor of the brushless motor to rotate, and a back electromotive force signal on the stator of the brushless motor is detected, including: If it is determined that the type of the starting signal is the first type, the power supply controller is controlled to drive the brushless motor through a constant voltage and frequency boost mode, and the back electromotive force signal on at least one stator of the brushless motor is collected through the back electromotive force sensor; wherein the first type is used to indicate that the brushless motor rotates from a standstill to a first specified speed within a first time; the first time is greater than a preset split time; the first specified speed is less than a preset split speed; the constant voltage and frequency boost mode is a driving strategy in which the voltage value of the starting voltage output by the power supply controller to the brushless motor remains unchanged and the voltage frequency gradually increases; the starting voltage is the voltage used by the power supply controller to drive the rotor of the brushless motor to rotate; If it is determined that the type of the starting signal is the second type, the power supply controller is controlled to drive the brushless motor through a constant frequency boost mode, and the back electromotive force signal on at least one stator of the brushless motor is collected through the back electromotive force sensor; wherein the second type is used to indicate that the brushless motor rotates from a standstill to a second specified speed within a second time; the second time is greater than the split time; the second specified speed is greater than or equal to the split speed; the constant frequency boost mode is a driving strategy in which the voltage frequency of the starting voltage output by the power supply controller to the brushless motor remains unchanged and the voltage value gradually increases; If it is determined that the type of the starting signal is the third type, the brushless motor is driven by the frequency-boosting mode, and the back-electromotive force signal on at least one stator of the brushless motor is collected by the back-electromotive force sensor; wherein, the third type is used to indicate that the brushless motor rotates from a standstill to a third specified speed within a third time; the third time is less than or equal to the division time; the third specified speed is greater than or equal to the division speed; the frequency-boosting mode is a driving strategy in which the voltage frequency and voltage value of the starting voltage output by the power controller to the brushless motor are gradually increased.

4. The starting method according to claim 1, characterized in that: Determining the estimated speed and estimated position of the brushless motor according to the back electromotive force signal through a closed-loop control strategy, including: If the speed of the motor exceeds the preset closed-loop speed, and more than N back-electromotive force zero-crossing signals are detected from at least one of the stators during the preset closed-loop period, the collected back-electromotive force signals are converted into back-electromotive force digital signals; The estimated speed and estimated position of the brushless motor are determined according to the back electromotive force digital signal and the motor parameters of the brushless motor; wherein the motor parameters include: the inductance of the stator in the brushless motor, the resistance of the stator in the brushless motor, the number of pole pairs of the brushless motor, and the rated voltage of the brushless motor.

5. The starting method according to claim 4, characterized in that: Determining an estimated speed and an estimated position of the brushless motor according to the back electromotive force digital signal and the motor parameters of the brushless motor, comprising: Inputting the motor parameters into a preset estimation model to obtain a target model; The target model is called to obtain the estimated rotation speed and the estimated position according to the back electromotive force signal.

6. The starting method according to claim 1, characterized in that: Controlling the power controller to drive the rotor of the brushless motor to reach a preset target speed according to the estimated speed and the estimated position includes: Obtaining the current starting voltage and starting current of each stator in the brushless motor from the power controller; Based on the current starting current of each stator, a first output signal is generated according to the speed difference between the target speed and the estimated speed, and the first output signal is sent to the power controller; wherein the first output signal is used to instruct the power controller to increase or decrease the starting current received by each stator to reduce the speed difference and make the speed of the rotor approach or reach the target speed.

7. The starting method according to claim 6, characterized in that: Based on the current starting current of each of the stators, a first output signal is generated according to a speed difference between the estimated speed and the target speed, including: Converting a starting current in at least one of the stators from a three-phase stationary coordinate system to a two-phase stationary coordinate system according to the estimated position to obtain a first DC component and a first quadrature-axis component; According to the speed difference between the target speed and the estimated speed, respectively adjusting the first DC component and the first quadrature-axis component to obtain a first DC adjustment component and a second quadrature-axis adjustment component; The first DC adjustment component and the second quadrature-axis adjustment component are converted from a two-phase stationary coordinate system to a three-phase stationary coordinate system to obtain a first output signal.

8. The starting method according to claim 1, characterized in that: Controlling the power controller to drive the rotor of the brushless motor to reach a preset target speed according to the estimated speed and the estimated position includes: The current flux of the brushless motor is determined according to the current starting voltage and starting current of each stator, and the second output signal is obtained according to the flux difference between the target flux corresponding to the target speed and the current flux, and the torque difference between the target torque corresponding to the target speed and the estimated torque; wherein the estimated torque is the current output torque of the rotor; the second output signal is used to instruct the power supply controller to increase or decrease the voltage vector of the starting voltage received by each stator to reduce the flux difference and the torque difference, and make the torque of the rotor approach or reach the target torque; when the flux difference and the torque difference are respectively zero, the speed of the rotor will reach the target speed.

9. The starting method according to claim 8, characterized in that: The second output signal is obtained according to the flux difference between the target flux corresponding to the target speed and the current flux, and the torque difference between the target torque corresponding to the target speed and the estimated torque, including: Obtaining a target torque corresponding to a target speed, and inputting the target torque into a direct torque controller to obtain a target flux; Controlling the direct torque controller to obtain the instantaneous flux linkage of the brushless motor according to the instantaneous voltage of the stator winding in the brushless motor; Invoking a hysteresis comparator in the direct torque controller to calculate a torque difference between the estimated torque and the target torque, and a flux difference between the instantaneous flux and the target flux; If the hysteresis comparator determines that the torque difference exceeds a preset torque threshold value, and / or the flux difference exceeds a preset flux threshold value, a second output signal is generated according to a preset torque-flux mapping table; wherein the torque-flux mapping table records at least one torque difference value, an indication corresponding to each torque difference value, and a voltage vector corresponding to each torque difference value and each flux difference value.

10. A starting device for a brushless motor, characterized in that: The starting device is connected to a power controller, the power controller is connected to at least one stator in the brushless motor, and the power controller is used to output a starting voltage and a starting current to the stator; The starting device is also connected to a position sensor, which is connected to the rotor in the brushless motor, and is used to detect the rotation angle of the rotor; The starting device is also connected to at least one back electromotive force sensor, one of the back electromotive force sensors is connected to one of the stators, and the back electromotive force sensor is used to detect the back electromotive force on the stator; The starting device comprises: A starting module, configured to control the power controller to drive the rotor of the brushless motor to rotate to a starting position in response to receiving a starting signal; wherein the starting signal is used to instruct the rotor of the brushless motor to rotate to a specified speed; and the starting position is a starting position at which the rotor starts to rotate; An open-loop control module, used to control the power controller to drive the rotor of the brushless motor to rotate through an open-loop control strategy, and detect the back-electromotive force signal on the stator of the brushless motor through the back-electromotive force sensor; wherein the open-loop control strategy is an operation strategy for controlling the rotation of the rotor of the brushless motor based on a position sensor; the back-electromotive force signal is the induced electromotive force generated in the stator when the rotor rotates and cuts the magnetic flux lines in the stator; A closed-loop control module is used to determine the estimated speed and estimated position of the brushless motor according to the back-electromotive force signal through a closed-loop control strategy, and control the power controller to drive the speed of the rotor of the brushless motor to reach a preset target speed according to the estimated speed and the estimated position; wherein the closed-loop control strategy is an operating strategy for controlling the rotation of the rotor of the brushless motor based on the back-electromotive force; the estimated speed is the rotor rotation speed corresponding to the back-electromotive force signal; and the estimated position is the rotor rotation angle corresponding to the back-electromotive force signal.

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