PMSM Phase Current Detection via Sector-Threshold Vector Analysis
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Solution Overview
Problem
Existing motor control methods for permanent magnet synchronous motors are inadequate for detecting insufficient or missing phase currents, which can result from degradation or improper assembly, leading to operational issues and increased maintenance costs.
Innovation Solution
A method and system that measure phase currents and determine the composite rotating current vector position within a stator frame, comparing the absolute value to a calibrated threshold, and executing responses such as generating fault codes, activating indicators, or transmitting diagnostic information when the current falls below the threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If typical motor control methods are used, then the motor can operate, but insufficient or missing phase currents cannot be detected timely
Solution Approach 1:
The patent applies preliminary action by establishing predetermined motor conditions and calibrated thresholds before operation. The system pre-defines sector numbers corresponding to different current thresholds, allowing it to proactively detect insufficient phase currents before they cause motor damage or failure.
Solution Approach 2:
The patent implements dynamics by continuously measuring phase currents and dynamically determining electrical current vector positions relative to a rotating reference frame. The system adapts the detection criteria based on the motor's operating sector, enabling real-time detection of insufficient currents across varying operational conditions.
2Measurement precision
If phase current monitoring is implemented, then detection accuracy improves, but processing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the electrical current space into discrete sectors (sector numbers 0-7). Each sector corresponds to specific phase combinations and current threshold ranges. This segmentation simplifies the complex continuous measurement problem into discrete, manageable categories that are easier to process and compare against calibrated thresholds.
Solution Approach 2:
The patent utilizes parameter changes by transforming the three-phase current measurements into a rotating reference frame and determining vector positions. This coordinate transformation simplifies the comparison process by converting complex multi-dimensional current data into a single sector number and corresponding threshold value, reducing processing complexity while maintaining detection accuracy.
3Reliability
If continuous phase current measurement is performed, then operational reliability improves, but energy consumption increases
Solution Approach 1:
The patent implements periodic action by measuring phase currents at specific intervals and only when predetermined motor conditions are met. Rather than continuously monitoring at maximum resolution, the system performs measurements periodically and compares them against pre-established sector-based thresholds, reducing computational energy consumption while maintaining reliable detection capability.
Data Source
AI summary
A method is provided for detecting an insufficient or missing phase current in a permanent magnet synchronous motor, and includes determining a composite vector position of a combined three-phase phase current with respect to a stationary portion of the motor, and assigning a sector to the position. The method includes comparing the phase current to a calibrated threshold current corresponding to the sector, and executing a response when the absolute value is less than the threshold. A vehicle includes an energy storage device (ESD), a motor/generator configured as a permanent magnet synchronous motor, a voltage inverter, and a bus for conducting DC current from the ESD to the inverter. A controller detects an insufficient phase current, determines a current vector position of the three-phase AC, assigns a sector to the position, and executes a response when an absolute value of the phase current is less than a calibrated threshold.