Electric Motor Torque Abnormality Control for Drive Continuity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional motor control devices cannot accurately determine the continuity of a drive operation in a motor when abnormality is detected in the output torque, leading to premature halting of the motor operation.
Innovation Solution
The proposed electric motor control device includes an electric-current instruction calculation unit, a detected phase-current calculation unit, a control calculation unit, an electrical angle calculation unit, an abnormal torque estimation unit, and a cutoff management unit, which work together to assess the abnormality of the motor's torque and decide whether to continue or halt the drive operation based on the severity of the abnormality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional failure detection device detects abnormality in electric current, then the motor drive operation is halted to prevent unintended operations, but the motor operation is prematurely halted even when the abnormality does not affect the continuity of drive operation
Solution Approach 1:
The patent replaces the conventional electric current-based failure detection mechanism with a torque-based detection mechanism. By calculating estimated torque from electric current and comparing it with actual torque feedback, the system can detect abnormalities that truly affect motor output rather than merely detecting electrical anomalies. This substitution allows the system to distinguish between detectable electrical faults and actual mechanical/torque failures, enabling continued operation when torque output remains normal.
2Productivity
If the motor control device continues drive operation when abnormality is detected, then the productivity is improved by avoiding unnecessary halts, but the reliability deteriorates due to potential unintended operations
Solution Approach 1:
The patent implements a feedback mechanism where the actual torque output of the motor is monitored and compared with the estimated torque calculated from electric current. This closed-loop feedback allows the system to continuously verify whether the motor is producing the expected torque output. When the feedback shows that actual torque matches estimated torque despite detected abnormalities, the system confidently continues operation, knowing that the motor output remains controlled and intended.
3Device complexity
If the failure detection device uses electric current detection means, then the device complexity is reduced, but the measurement precision deteriorates because electric current abnormality does not necessarily indicate torque output abnormality
Solution Approach 1:
The patent segments the detection function into two independent components: electric current detection (for estimating torque) and actual torque detection (for verification). By separating these functions and comparing their results, the system achieves more precise abnormality detection than either component alone. The electric current detection provides an expected torque value, while the actual torque detection provides ground truth, and their comparison precisely identifies whether the abnormality affects motor output.
Data Source
AI summary
An electric motor control device comprises: an abnormal torque estimation unit for estimating abnormality of torque of an electric motor from target electric-current values determined by an electric-current instruction calculation unit, detected electric-current values obtained by a detected phase-current calculation unit, and an electrical angle calculated by an electrical angle calculation unit; and a cutoff management unit for halting a drive operation of the motor if its output torque is abnormal.