Static Electrical Reference Measurement for PMSM
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Solution Overview
Problem
Current methods for measuring electrical references in three-phase permanent magnet synchronous motors require the motor to run in a generator mode, leading to noise production and the need for multiple devices, making the process inconvenient and costly.
Innovation Solution
A static measuring method that locks the motor's rotation axis with a mechanical brake, allowing for the measurement of resistance and inductance without motor operation, using controlled voltage inputs and vector control to calculate electrical references.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the motor runs in generator mode for measurement, then electrical references can be obtained, but noise is produced and multiple devices are required
Solution Approach 1:
Instead of running the motor in generator mode to measure electrical references, the patent inverts the approach by measuring the motor in static condition using voltage injection and calculating the electrical references from the measured currents. This eliminates the need for motor rotation and associated noise generation while achieving the same measurement objective.
Solution Approach 2:
The patent replaces the mechanical rotation-based measurement system with an electrical measurement system. By injecting known voltages and measuring resulting currents in the stationary motor, the electrical references are calculated without requiring mechanical motion, thereby eliminating noise from motor operation.
2Measurement precision
If the motor runs in generator mode for measurement, then electrical references can be obtained, but various devices and complex procedures are needed
Solution Approach 1:
The motor itself serves as the measurement object without requiring external generator equipment. The patent uses the motor's own windings and electrical characteristics to perform self-measurement by injecting voltages and measuring currents, eliminating the need for separate generator machines and complex measurement setups.
Solution Approach 2:
The patent changes the measurement parameters from dynamic operational measurements (during generator mode) to static electrical parameter measurements. By measuring voltage and current in stationary condition and calculating electrical references through mathematical relationships, the complexity of dynamic measurement systems is avoided.
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
Enables precise measurement of electrical references at a static state, reducing noise and device requirements, simplifying the process, and lowering costs while maintaining accuracy.
Implementation Method 1
locks a rotation axis of the measuring motor by a mechanical brake so that the motor is not rotating
Implementation Method 2
a transducer (I) respectively connected with three voltage input ends (MU, MV, and MW) of the PMSM, wherein the transducer (I) controls an output voltage into the PMSM
Implementation Method 3
inputting a rated current of the PMSM and 150% of the rated current at a state of locking an axle of the PMSM, recording corresponding voltage V100% and V150%, and dividing the voltage differecne with the current differnce to obtain the resistance of the PMSM
Implementation Method 4
dividing an electrical period into six voltage vectors at a state of vector controlling, and performing four voltage cycles under every the voltage vector... compare rising times of the voltage vectors and convert the rising times to inductances
Data Source
AI summary
A method for measuring a resistance and an inductance of a permanent magnet synchronous motor (PMSM) in a static state includes inputting a rated current of the PMSM and 150% of the rated current at a state of locking an axle of the PMSM, recording corresponding voltages V100% and V150%, and dividing the voltage difference with the current difference to obtain the resistance of the PMSM. The method continues dividing an electrical period into six voltage vectors, and performing four voltage cycles for every the voltage vector. The voltage cycle includes step of outputting a quarter of the voltage V150%, and outputting the voltage V150% after the current being stable. After one of the six voltage vectors being finished, the method switches to the other voltage vectors and repeats the voltage cycles, and the method is completed till all of the six voltage vectors being finished. Finally, the method continues to compare rising times of the voltage vectors and convert the rising times to inductances, and to define the maximum of the inductances as an inductance of a q axis and to define the minimum of the inductances as an inductance of a d axis.