Permanent Magnet Motor Inter-Turn Short Detection Across Speed Ranges
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Solution Overview
Problem
Existing systems struggle to reliably and quickly detect inter-turn short circuits in permanent magnet synchronous machines, which can lead to motor phase burnout due to unmanaged fault currents.
Innovation Solution
A method for detecting inter-turn short circuits by monitoring imbalances between motor phases using motor terminal voltages and currents, employing high-frequency signal injection at low speeds and voltage imbalance detection at higher speeds, utilizing existing motor controller hardware without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fault detection systems are used, then the system can identify faults after winding burnout occurs, but the detection reliability and speed are insufficient to prevent motor damage
Solution Approach 1:
The patent performs preliminary action by detecting inter-turn short circuits before they propagate and cause winding burnout. The detection method monitors phase current imbalances and voltage drops in real-time, enabling early fault identification when the short circuit first occurs, allowing preventive shutdown before catastrophic damage happens.
Solution Approach 2:
The patent implements feedback by continuously monitoring motor phase currents and comparing them to detect imbalances indicative of inter-turn short circuits. The system uses real-time current measurements from existing sensors, processes the signals to identify fault patterns, and provides immediate feedback to trigger protective shutdown, creating a closed-loop fault detection and protection system.
2Measurement precision
If additional sensors are added to improve detection capability, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent applies self-service by using the motor controller's existing current sensors and processing capabilities to detect inter-turn short circuits. The system leverages the already-present measurement infrastructure, eliminating the need for additional dedicated fault detection sensors. The existing current measurement circuitry serves dual purposes: motor control and fault detection.
Solution Approach 2:
The patent implements universality by designing a detection method that uses the existing current sensors for both their primary function (motor control) and secondary function (fault detection). The same hardware infrastructure serves multiple purposes, and the detection algorithm can identify various fault types including inter-turn short circuits, phase losses, and current sensor failures using the same measurement system.
Data Source
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AI summary
A short circuit detection system and method that identifies a short circuit between turns of a winding of a permanent magnet machine having a three-phase winding in response to detection of imbalances between the three motor phases at an instant in time. The imbalances are identified by monitoring motor terminal voltages and currents.