Motor Control Apparatus Initial Position Learning Error Correction
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Solution Overview
Problem
In electric motor systems with encoders, the initial position learning process can be erroneous due to looseness in the rotation transmission system, leading to incorrect alignment of the rotor's rotational position and exciting phase, which may result in improper motor operation.
Innovation Solution
A motor control apparatus that uses an encoder to output A-phase and B-phase signals at predetermined intervals, sequentially changes the exciting phases during the initial drive operation to synchronize the rotor's position with the corresponding phase, and re-executes the learning process if the alignment is found to be erroneous, ensuring accurate learning of the rotational position and phase relationship.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the initial position learning process is executed in the initial drive operation, then the relationship between encoder count value and rotor rotational position can be learned, but erroneous learning may occur due to looseness in the rotation transmission system
Solution Approach 1:
The patent applies feedback by monitoring the encoder output signal pattern during the initial drive operation and using this feedback to determine whether to re-execute the learning process. The control unit counts encoder pulses and detects the signal pattern to判断 if learning was successful, providing feedback that triggers re-execution if erroneous learning is detected
Solution Approach 2:
The patent implements preliminary action by re-executing the initial drive operation before considering the learning process complete. The system performs the learning process, validates the results through encoder signal pattern detection, and if validation fails, re-executes the entire initial drive operation to ensure correct learning before normal operation begins
2Ease of operation
If the rotor rotates within the range of looseness or is held at delimiting positions, then the motor may be driven, but the rotor may not reach the position corresponding to the exciting phase, resulting in erroneous learning
Solution Approach 1:
The control unit uses feedback from the encoder signal pattern to detect whether the rotor reached the correct position corresponding to the exciting phase. By monitoring the relationship between encoder count values and excitation phases, the system can determine if position alignment is correct and trigger re-execution if misalignment is detected
Solution Approach 2:
The patent replaces mechanical position verification with an electronic detection method using the encoder signal pattern. Instead of mechanically ensuring the rotor reaches the correct position, the system uses electronic sensing of the encoder output to verify position alignment and trigger appropriate corrective actions
Data Source
AI summary
At an initial drive operation after turning on of an electric power source, an ECU sequentially changes each current exciting phase among multiple phases through one complete cycle at a predetermined time schedule, so that a rotational position of a rotor and the corresponding exciting phase coincide with each other at some timing during the initial drive operation, and thereby the rotor is rotated. The ECU counts the A-phase signal and the B-phase signal during the rotation of the rotor in the initial drive operation and learns a relationship among a count value of the A-phase signal and the B-phase signal, a rotational position of the rotor and each exciting one of the plurality of phases at an end of the initial drive operation. When the ECU determines that a result of the learning is erroneous, the ECU re-executes the learning by re-executing the initial drive operation.