Open-loop control method of Hall motor

Abstract

The invention relates to the technical field of motor control, in particular to an open-loop control method of a Hall motor, which comprises the following steps of: configuring open-loop control parameters of the Hall motor; recording a closed-loop feedback speed in a closed-loop control process in real time, and judging whether the Hall sensor has a fault or not; when the Hall sensor breaks down, the closed-loop control is switched into open-loop control, and the method comprises the steps that according to the preset open-loop target speed and the open-loop acceleration, the open-loop expected speed is obtained through a ramp function; acquiring an open-loop electrical angle; whether the open-loop electrical angle is larger than 60 degrees or not is judged, if the open-loop electrical angle is larger than 60 degrees, the direction of the Hall sector is switched, and the open-loop electrical angle is reset; and calculating an open-loop output duty ratio according to the open-loop expected speed and the open-loop proportionality coefficient. During application, when the Hall sensor breaks down, closed-loop control is switched into open-loop control, and the rotating speed of the motor is smoothly adjusted to the target rotating speed, so that the motor can still operate normally when the Hall sensor breaks down.

Description

Technical Field

[0001] The invention relates to the technical field of motor control, and in particular to an open-loop control method of a Hall motor. Background Art

[0002] Hall motors are widely used in various automation equipment, especially in the control of brushless DC motors (BLDC). Hall sensors are used to detect the position of the motor rotor to control the motor. In the prior art, the control method of Hall motors is mainly closed-loop control. However, in the existing Hall motor closed-loop control system, it mainly relies on Hall signal measurement to control the operation of the motor through certain preset parameters.

[0003] However, it has the following shortcomings in practical applications, especially in sudden failures or extreme working conditions: 1. The Hall sensor is disconnected, resulting in control failure: When the Hall sensor fails or is disconnected, the closed-loop control of the motor cannot continue because the system relies on the feedback signal of the Hall sensor to accurately control the rotation of the motor. At this time, the motor cannot correctly determine the rotor position, causing the motor to stop running or work unstably; 2. Unable to cope with sudden failures: Existing closed-loop control systems usually lack emergency response mechanisms for Hall sensor failures, which means that the motor must be shut down or manually intervened when a sensor failure occurs, affecting the continuous operation of the system. 3. Poor adaptability to special working scenarios: In some application scenarios (such as automated production lines, drones, etc.), the motor must continue to run even when the Hall sensor fails to ensure the normal operation of the equipment. Existing closed-loop control systems fail to effectively solve this problem, resulting in inability to operate stably in these scenarios. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an open-loop control method for a Hall motor. When applied, the method combines closed-loop control with open-loop control. When the Hall sensor does not fail, the motor is controlled to maintain normal operation through closed-loop control. When the Hall sensor fails, the closed-loop control is switched to open-loop control, and the motor speed is smoothly adjusted to the target speed, so that the motor can still maintain normal operation when the Hall sensor fails.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions: An open-loop control method for a Hall motor comprises the following steps: Configure the Hall motor open-loop control parameters, including open-loop target speed, open-loop acceleration, and open-loop proportional coefficient; Real-time record of closed-loop feedback speed during closed-loop control, and determine whether the Hall sensor is faulty; If the Hall sensor fails, the Hall sensor fault is reported and the closed-loop feedback speed at that time is used as the open-loop feedback speed, and the motor control mode is switched from closed-loop control to open-loop control; if the Hall sensor does not fail, the switching direction of the Hall sector is determined, the electrical angle required for open-loop control is cleared, and the open-loop Hall sector is set equal to the current Hall sector; When the Hall sensor fails, the closed-loop control is switched to open-loop control, including: According to the preset open-loop target speed and open-loop acceleration, the ramp function is used to obtain the open-loop desired speed; Get the open loop electrical angle; Determine whether the absolute value of the open-loop electrical angle is greater than 60°. If the open-loop electrical angle is greater than 60°, switch the direction of the Hall sector and clear the open-loop electrical angle. The open-loop output duty cycle is calculated based on the open-loop desired speed and the open-loop proportional coefficient.

[0006] In the prior art, when the Hall sensor fails, since the closed-loop control system relies on the feedback signal of the Hall sensor to accurately control the rotation of the motor, the closed-loop control system of the motor cannot continue at this time, so that the motor cannot correctly judge the rotor position, causing the motor to stop running or work unstably. The existing closed-loop control system usually lacks an emergency processing mechanism for the Hall sensor failure. Therefore, when the motor fails, it is necessary to shut down or perform manual intervention, which affects the continuous operation of the system. In this application, by combining closed-loop control with open-loop control, when the Hall sensor does not fail, the closed-loop control method is used to maintain the stable operation of the Hall motor. When the Hall sensor fails, it is switched to an open-loop control method. At this time, according to the preset open-loop target speed and open-loop acceleration, the ramp function is used to calculate the open-loop desired speed, and the open-loop electrical angle is calculated. The size of the open-loop electrical angle is judged, thereby judging the direction of the Hall sector and switching the open-loop Hall sector. Finally, the open-loop output duty cycle is calculated according to the open-loop desired speed and the open-loop proportional coefficient, so as to stably control the motor operation when the Hall sensor fails. In the present application, since the closed-loop control is switched to the open-loop control when the Hall sensor fails, the motor speed can be adjusted to the open-loop target speed during the open-loop control, thereby preventing the motor from stalling or unstable operation. In the open-loop control mode, the angle of the motor rotor is no longer fed back through the Hall sensor, but is simulated by the open-loop electrical angle calculated by the system, so even if the Hall sensor fails, the speed and angle can still be kept consistent. At the same time, in the present application, the motor speed is adjusted by a ramp function, which gradually increases or decreases the motor speed until the open-loop target speed is reached, thereby avoiding sudden speed changes and preventing the motor from overloading or vibrating due to too fast speed changes.

[0007] In a possible implementation, the basis for determining whether the Hall sensor fails is to determine whether the Hall sector is within a range of 1 to 6. If continuous values ​​outside the range occur, it is determined that the Hall sensor fails.

[0008] In a possible implementation, the open-loop desired speed is obtained using a ramp function according to a preset open-loop target speed and an open-loop acceleration, specifically in the following manner: ,in, represents the open-loop desired speed, represents the open-loop feedback speed, represents the open-loop acceleration, represents the Hall sampling frequency, In this application, the open-loop desired speed That is the output value of the ramp function, the open-loop feedback speed That is the current value of the ramp function, the open-loop acceleration is the slope of the ramp function, the open-loop target speed is the target value of the ramp function, the Hall sampling frequency This is the time step of the ramp function. If the target value Greater than the current value Add the change in each time step, that is , then the output value is the current value Add the change; if the target value Less than the current value Subtract the change in each time step, that is , then the output value is the current value Subtract the change; if the target value Between current values Plus the change in each time step and the current Subtract the change in each time step, and the output value is Equal to target speed Output value According to the target value The size of the Adjust to target value , and according to the set ramp function slope and time step Limit the amount of change at each time step.

[0009] In a possible implementation, the open-loop electrical angle is obtained as follows: Get the Hall sampling frequency of the motor Angle change within : ,in, Indicates the number of motor pole pairs.

[0010] In this application, the desired motor speed is , convert the motor speed from rpm to ° / s and then multiply by the number of motor pole pairs , according to the number of motor pole pairs To adjust the electrical angle change of the motor, and finally multiply it by the time step , converting the angular change per second into the angle per time step The angle change is used to smoothly update the motor angle.

[0011] The angle change Add to the current motor angle to get the open-loop electrical angle : ,in, Indicates the current motor angle.

[0012] Determine the open loop electrical angle Is the absolute value greater than 60°? If so, the open-loop electrical angle Clear to zero and adjust according to the speed direction ( The sign of ) switches the Hall sector.

[0013] In a possible implementation, the open-loop output duty cycle is calculated according to the open-loop desired speed and the open-loop proportional coefficient as follows: ,in, represents the open-loop output duty cycle, In this application, the open-loop desired speed is obtained according to the ramp function. With the preset open loop proportional coefficient Calculate the open-loop output duty cycle. According to the Hall sector and the open-loop output duty cycle, the output of the PWM wave is controlled to drive the motor to operate. This part is well known and will not be repeated here. In this application, by adjusting the output duty cycle and switching the Hall sector, the motor can run stably and accurately control the speed, avoiding shutdown or instability caused by Hall sensor failure.

[0014] In a possible implementation, during the open-loop control of the motor, if the fault of the Hall sensor is repaired, the open-loop control is switched to the closed-loop control.

[0015] In summary, the present invention has the following beneficial effects compared with the prior art: the present invention uses open-loop control to simulate the state of the motor rotor by using parameters such as open-loop feedback speed and open-loop electrical angle when the Hall sensor fails, so as to ensure that the motor continues to operate without Hall sensor feedback and avoid motor shutdown or unstable operation; the present invention uses open-loop target speed, open-loop acceleration and open-loop proportional coefficient to smoothly adjust the speed of the motor by using a ramp function after the Hall sensor fails, so as to avoid drastic changes of the speed being too fast or too slow, and the acceleration control in the speed adjustment process ensures that the motor smoothly transitions to the target speed, thereby improving the stability and reliability of the system; the present invention combines the open-loop desired speed with the open-loop proportional coefficient to obtain a suitable open-loop output duty cycle, and smoothly adjusts the PWM signal by the output duty cycle, thereby ensuring the output stability of the motor in the open-loop control mode and avoiding motor speed fluctuation or inaccurate control due to an unstable duty cycle; the present invention can seamlessly switch to the open-loop control mode when the Hall sensor fails, and keep the motor running stably through an accurate open-loop control algorithm, thereby enhancing the system robustness and making the system have a strong fault tolerance to Hall sensor failures. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings: Figure 1 is a flow chart of an embodiment of the present invention; Figure 2 It is a schematic diagram of the closed-loop control switching to open-loop control according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0018] Example: like Figure 1 As shown, an open-loop control method of a Hall motor comprises the following steps: Configure the Hall motor open-loop control parameters, including open-loop target speed, open-loop acceleration, and open-loop proportional coefficient; Real-time record of closed-loop feedback speed during closed-loop control, and determine whether the Hall sensor is faulty; If the Hall sensor fails, the Hall sensor fault is reported and the closed-loop feedback speed at that time is used as the open-loop feedback speed, and the motor control mode is switched from closed-loop control to open-loop control; if the Hall sensor does not fail, the switching direction of the Hall sector is determined, the electrical angle required for open-loop control is cleared, and the open-loop Hall sector is set equal to the current Hall sector; When the Hall sensor fails, the closed-loop control is switched to open-loop control, including: According to the preset open-loop target speed and open-loop acceleration, the ramp function is used to obtain the open-loop desired speed; Get the open loop electrical angle; Determine whether the open-loop electrical angle is greater than 60°. If the open-loop electrical angle is greater than 60°, switch the direction of the Hall sector and clear the open-loop electrical angle. The open-loop output duty cycle is calculated based on the open-loop desired speed and the open-loop proportional coefficient.

[0019] In the prior art, when the Hall sensor fails, since the closed-loop control system relies on the feedback signal of the Hall sensor to accurately control the rotation of the motor, the closed-loop control system of the motor cannot continue at this time, so that the motor cannot correctly judge the rotor position, causing the motor to stop running or work unstably. The existing closed-loop control system usually lacks an emergency processing mechanism for the Hall sensor failure. Therefore, when the motor fails, it is necessary to shut down or perform manual intervention, which affects the continuous operation of the system. In this application, by combining closed-loop control with open-loop control, when the Hall sensor does not fail, the closed-loop control method is used to maintain the stable operation of the Hall motor. When the Hall sensor fails, it is switched to an open-loop control method. At this time, according to the preset open-loop target speed and open-loop acceleration, the ramp function is used to calculate the open-loop desired speed, and the open-loop electrical angle is calculated. The size of the open-loop electrical angle is judged, thereby judging the direction of the Hall sector and switching the open-loop Hall sector. Finally, the open-loop output duty cycle is calculated according to the open-loop desired speed and the open-loop proportional coefficient, so as to stably control the motor operation when the Hall sensor fails. In the present application, since the closed-loop control is switched to the open-loop control when the Hall sensor fails, the motor speed can be adjusted to the open-loop target speed during the open-loop control, thereby preventing the motor from stalling or unstable operation. In the open-loop control mode, the angle of the motor rotor is no longer fed back through the Hall sensor, but is simulated by the open-loop electrical angle calculated by the system, so even if the Hall sensor fails, the speed and angle can still be kept consistent. At the same time, in the present application, the motor speed is adjusted by a ramp function, which gradually increases or decreases the motor speed until the open-loop target speed is reached, thereby avoiding sudden speed changes and preventing the motor from overloading or vibrating due to too fast speed changes.

[0020] In a possible implementation, the basis for determining whether the Hall sensor fails is to determine whether the Hall sector is within a range of 1 to 6. If continuous values ​​outside the range occur, it is determined that the Hall sensor fails.

[0021] In a possible implementation, the open-loop desired speed is obtained using a ramp function according to a preset open-loop target speed and an open-loop acceleration, specifically in the following manner: ,in, represents the open-loop desired speed, represents the open-loop feedback speed, represents the open-loop acceleration, represents the Hall sampling frequency, In this application, the open-loop desired speed That is the output value of the ramp function, the open-loop feedback speed That is the current value of the ramp function, the open-loop acceleration is the slope of the ramp function, the open-loop target speed is the target value of the ramp function, the Hall sampling frequency This is the time step of the ramp function. If the target value Greater than the current value Add the change in each time step, that is , then the output value is the current value Add the change; if the target value Less than the current value Subtract the change in each time step, that is , then the output value is the current value Subtract the change; if the target value Between current values Plus the change in each time step and the current Subtract the change in each time step, and the output value is Equal to target speed Output value According to the target value The size of the Adjust to target value , and according to the set ramp function slope and time step Limit the amount of change at each time step.

[0022] In a possible implementation, the open-loop electrical angle is obtained as follows: Get the Hall sampling frequency of the motor Angle change within : ,in, Indicates the number of motor pole pairs; In this application, the desired motor speed is , convert the motor speed from RPM to ° / S and then multiply by the number of motor pole pairs , according to the number of motor pole pairs To adjust the electrical angle change of the motor, and finally multiply it by the time step , converting the angular change per second into the angle per time step The angle change is used to smoothly update the motor angle.

[0023] The angle change Add to the current motor angle to get the open-loop electrical angle : ,in, Indicates the current motor angle.

[0024] Determine the open loop electrical angle Is the absolute value greater than 60°? If so, the open-loop electrical angle Clear to zero and adjust according to the speed direction ( The symbol of the Hall effect switch is shown in Table 1. Table 1 Hall sector switching logic table

[0025] In a possible implementation, the open-loop output duty cycle is calculated according to the open-loop desired speed and the open-loop proportional coefficient as follows: ,in, represents the open-loop output duty cycle, In this application, the open-loop desired speed is obtained according to the ramp function. With the preset open loop proportional coefficient Calculate the open-loop output duty cycle. According to the Hall sector and the open-loop output duty cycle, the output of the PWM wave is controlled to drive the motor to operate. This part is common knowledge and will not be repeated. In this application, by adjusting the output duty cycle and switching the Hall sector, the motor can run stably and accurately control the speed, avoiding shutdown or instability caused by Hall sensor failure.

[0026] In a possible implementation, during the open-loop control of the motor, if the fault of the Hall sensor is repaired, the open-loop control is switched to the closed-loop control.

[0027] like Figure 2 The diagram shows the switching from closed-loop control to open-loop control, where the closed-loop target speed is 4000RPM, the open-loop target speed is 2000RPM, CH1 (red) indicates the actual feedback speed of the motor, and CH2 (green) indicates the open-loop feedback speed. , CH3 (black) indicates Hall fault sign × 1000, Figure 2 It can be seen that the Hall motor is in closed-loop control within 0~5000ms, and the open-loop feedback speed is Equal to the feedback speed FBV, when the Hall sensor fails, that is, when CH3 suddenly changes, the motor speed drops to the open-loop target speed under the action of the ramp function In this process, the switching of the Hall sectors and the output of the duty cycle are realized through calculation to control the operation of the motor and avoid the occurrence of motor stalling.

[0028] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An open-loop control method for a Hall motor, characterized in that: The following steps are involved: Configure the Hall motor open-loop control parameters, including open-loop target speed, open-loop acceleration, and open-loop proportional coefficient; Real-time record of closed-loop feedback speed during closed-loop control, and determine whether the Hall sensor is faulty; If the Hall sensor fails, the Hall sensor fault is reported and the closed-loop feedback speed at that time is used as the open-loop feedback speed, and the motor control mode is switched from closed-loop control to open-loop control; if the Hall sensor does not fail, the switching direction of the Hall sector is determined, the electrical angle required for open-loop control is cleared, and the open-loop Hall sector is set equal to the current Hall sector; When the Hall sensor fails, the closed-loop control is switched to open-loop control, including: According to the preset open-loop target speed and open-loop acceleration, the ramp function is used to obtain the open-loop desired speed; Get the open loop electrical angle; Determine whether the absolute value of the open-loop electrical angle is greater than 60°. If the open-loop electrical angle is greater than 60°, switch the direction of the Hall sector and clear the open-loop electrical angle. The open-loop output duty cycle is calculated based on the open-loop desired speed and the open-loop proportional coefficient.

2. The open-loop control method of a Hall motor according to claim 1, characterized in that: The basis for judging whether the Hall sensor has a fault is to judge whether the Hall sector is within the range of 1 to 6. If continuous non-range values ​​occur, it is judged that the Hall sensor has a fault.

3. The open-loop control method of a Hall motor according to claim 1, characterized in that: According to the preset open-loop target speed and open-loop acceleration, the ramp function is used to obtain the open-loop desired speed. The specific method is as follows: ,in, represents the open-loop desired speed, represents the open-loop feedback speed, represents the open-loop acceleration, represents the Hall sampling frequency, Indicates the open loop target speed.

4. The open-loop control method of a Hall motor according to claim 3, characterized in that: Get the open-loop electrical angle, specifically: Get the motor's Hall sampling frequency Angle change within : ,in, Indicates the number of motor pole pairs; The angle change Add to the current motor angle to get the open-loop electrical angle : ,in, Indicates the current motor angle.

5. The open-loop control method of a Hall motor according to claim 3, characterized in that: The open-loop output duty cycle is calculated based on the open-loop desired speed and the open-loop proportional coefficient: ,in, represents the open-loop output duty cycle, Represents the open loop proportional coefficient.

6. The open-loop control method of a Hall motor according to claim 1, characterized in that: During the open-loop control of the motor, if the fault of the Hall sensor is repaired, the open-loop control is switched to closed-loop control.

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