Synchronous Motor Control via Phase Difference Feedback
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Solution Overview
Problem
The output signal from sensors detecting the angular position of the output shaft of a decelerating mechanism in synchronous motor systems has lower accuracy and resolution compared to sensors detecting the magnetic pole position, leading to signal degradation and instability in motor operation, especially when noise is introduced through long harnesses.
Innovation Solution
A control device that includes a sensor to detect the angle of the output shaft, processing circuitry to convert the detected angle into a multiple rotation angle, and feedback control mechanisms to stabilize the phase difference and position of the synchronous motor, using both phase difference and position feedback to control energization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If averaging or filtering of the sensor output signal is performed to improve accuracy, then measurement precision is improved, but a lag occurs in the output signal
Solution Approach 1:
The patent implements feedback control by comparing the detected angular position with the target position and adjusting the motor control accordingly. This feedback mechanism allows the system to achieve high positioning accuracy without requiring excessive signal filtering that would cause lag, as the control system actively compensates for position errors in real-time.
2Ease of operation
If the distance between the sensor and electronic circuit is increased, then ease of operation is improved, but noise invades through the harness
Solution Approach 1:
The patent introduces an intermediary processing stage where the sensor output signal is read by a dedicated sensor reading unit that interfaces between the sensor and the main electronic circuit. This intermediary structure allows for signal conditioning and processing that reduces noise susceptibility while maintaining installation flexibility.
3Device complexity
If a sensor detecting the output shaft angle is used instead of a magnetic pole position sensor, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent replaces the need for high-precision magnetic pole position sensing with a simpler output shaft angle sensor. Compensation for the lower intrinsic precision of the simpler sensor is achieved through feedback control and multiple rotation angle calculation, substituting mechanical sensing precision with control system intelligence.
4Ease of operation
If feedback control is performed using degraded sensor output signal, then ease of operation is maintained, but stability of operation deteriorates
Solution Approach 1:
The patent implements comprehensive feedback control that reads the sensor output signal and uses it to calculate the multiple rotation angle and compare with target position. This feedback mechanism stabilizes motor operation by continuously correcting position errors, even when the raw sensor signal has degraded quality, thereby maintaining operational stability without sacrificing ease of operation.
Data Source
AI summary
A sensor (110) detects the angle of the output shaft (101a) of a synchronous motor (101). A multiple rotation processing unit (301) converts the angle of one rotation or more that is detected by the sensor (110) into a multiple rotation angle. A phase difference FB unit (305) performs feedback control in such a way that the phase difference between the electrical angle and the mechanical angle of the synchronous motor (101) is a target phase difference (306). A position FB unit (302) performs feedback control in such a way that the multiple rotation angle after conversion by the multiple rotation processing unit (301) is a target position (303).