PMSM Flux Characterization for Adaptive Traction Motor Control
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Solution Overview
Problem
Current methods for characterizing and adapting control parameters of permanent magnetic synchronous motors (PMSMs) are inadequate, as they do not fully account for the magnetic flux variations with current, leading to inefficiencies and potential premature failure.
Innovation Solution
A method that involves estimating the linked magnetic flux as a function of current, combining it with the permanent magnet flux, and adapting control parameters to optimize PMSM operation, including current control, by performing standstill characterization and retardation tests to determine flux characteristics and no-load power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard control parameters are used without adaptation, then the PMSM operation is simplified, but efficiency and reliability are reduced due to unaccounted magnetic flux variations
Solution Approach 1:
The patent performs standstill characterization tests before normal operation to pre-determine the flux characteristic of the PMSM. By conducting these tests in advance (providing PM flux, performing standstill characterization to estimate linked magnetic flux as a function of current, adding PM flux to provide complete flux characteristic), the system prepares adaptation data beforehand, which then enables reliable operation without real-time complexity.
2Use of energy by moving object
If magnetic flux variations with current are not accounted for, then control is simpler, but efficiency deteriorates due to suboptimal current control
Solution Approach 1:
The patent replaces complex real-time magnetic flux measurement during operation with a simplified standstill characterization approach. By performing tests at standstill (where the rotor is stationary) to estimate linked magnetic flux as a function of current, and combining this with provided PM flux, the system obtains the flux characteristic without requiring complex dynamic measurement systems during motor operation.
3Measurement precision
If standstill characterization is performed to estimate linked magnetic flux, then flux characteristic accuracy is improved, but testing time and complexity increase
Solution Approach 1:
The patent performs standstill characterization tests periodically (either at manufacturing, during maintenance intervals, or when the vehicle is stationary), rather than continuously during operation. This periodic approach provides accurate flux characteristic data when needed while minimizing time loss, as the tests are conducted during natural stop periods rather than requiring continuous testing during motor operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the efficiency and reliability of PMSM operation by adapting control parameters based on flux characteristics, predicting potential failures, and enhancing predictive maintenance, thereby extending the lifespan and performance of the motor.
Implementation Method 1
The permanent magnets (e.g. Neodymium magnets) are typically embedded in the rotor to create a constant magnetic field, and the stator comprises stator windings connected to the AC supply to produce the rotating magnetic field. At synchronous speed the rotor poles lock to the rotating magnetic field.
Implementation Method 2
The stator of the synchronous electric motor comprises multiphase AC electromagnets for creating a magnetic field which rotates in time with the oscillations of the line current.
Data Source
AI summary
A method for adapting the control parameters of an electric traction machine being a permanent magnetic synchronous motor, PMSM, the method comprising providing the flux linkage of the permanent magnets, PM flux, in the PMSM; performing a stand still characterisation of the PMSM to estimate linked magnetic flux as a function of current; adding the PM flux to the estimated linked magnetic flux to provide a flux characteristic of the PMSM; adapting the control parameters of the PMSM based on the flux characteristic.