Sensorless Motor Drive Startup With Angle Difference Control
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Solution Overview
Problem
In motor drives performing sensorless control, there is a challenge in promptly starting and stopping the motor while preventing step loss, which can lead to excessive torque fluctuations or motor failure.
Innovation Solution
A motor drive system that includes a power converter and a controller, where the controller creates an angle difference between a d-axis in a d-q rotating frame and a γ-axis estimating the d-axis to accelerate or decelerate the rotor. The controller ensures that the d-axis current remains within a certain range, the angular velocity increases or decreases monotonically, and the angle difference is kept within a specific range not including zero.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the angular acceleration of the rotor is increased to allow prompt startup, then the startup time is reduced, but the motor is more likely to lose steps
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the angle difference between the d-axis and γ-axis during rotor acceleration. By controlling this angle difference to be within a specific range (greater than 0 and less than or equal to a predetermined value), the system enables higher angular acceleration while preventing step loss, thus resolving the contradiction between startup speed and reliability
Solution Approach 2:
The patent implements feedback control by continuously monitoring the angle difference between the d-axis and γ-axis during sensorless control operation. Based on this feedback, the controller adjusts the voltage commands to maintain the angle difference within the optimal range, allowing the motor to achieve prompt startup without losing steps
2Loss of time
If the angular acceleration of the rotor is increased to allow prompt stopping, then the stopping time is reduced, but the motor is more likely to lose steps
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the angle difference between the d-axis and γ-axis during rotor deceleration. By controlling this angle difference to be within a specific range (greater than 0 and less than or equal to a predetermined value), the system enables higher angular acceleration for prompt stopping while preventing step loss
Solution Approach 2:
The patent implements feedback control by continuously monitoring the angle difference between the d-axis and γ-axis during sensorless control operation. Based on this feedback, the controller adjusts the voltage commands to maintain the angle difference within the optimal range, allowing the motor to stop promptly without losing steps
Data Source
AI summary
A motor drive includes a power converter and a controller. The power converter drives a motor which includes a rotor having a permanent magnet and a stator having a coil wound around the stator. The controller performs a sensorless control of the motor using the power converter. The controller creates an angle difference between a d axis and a γ axis to accelerate the rotor to start the motor, and controls a power converter so that, during acceleration of the rotor, a d-axis current remains within a certain range, an angular velocity of the rotor monotonically increases, and the angle difference is kept within a given range not including zero.