Synchronous Reluctance Motor Flux Mapping Without Bench Tests
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Solution Overview
Problem
Existing methods for adapting the magnetic characteristics of synchronous reluctance motors require costly laboratory tests and numerous measurements, making them inefficient and expensive, and lack consideration for anisotropy.
Innovation Solution
A method and apparatus that use an inverter and electronic motor-control system to automatically adapt magnetic characteristics by applying predetermined voltage and current variations, calculating differential inductances, and mapping flux curves with reduced measurements, ensuring accuracy similar to experimental testing without the need for bench tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laboratory bench tests with constant-speed run motor are used to measure magnetic characteristics, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The motor drives itself during measurement by operating in generator mode, eliminating the need for an external constant-speed run motor. The motor's own rotation generates electromotive forces that are measured to determine magnetic characteristics, making the system self-sufficient and reducing external equipment requirements.
Solution Approach 2:
The invention extracts only the essential measurement components needed for magnetic characteristics determination, removing the complex constant-speed run motor and associated test bench infrastructure. By measuring electromotive forces directly during motor operation, the system retains measurement accuracy while eliminating unnecessary equipment.
2Measurement precision
If a very large number of current steps are applied to map flux characteristics with appropriate accuracy, then measurement precision is improved, but loss of time and cost increase
Solution Approach 1:
The method applies periodic current variations at different frequencies to the motor during rotation, allowing flux characteristics to be mapped through frequency-domain analysis. This periodic excitation approach enables accurate characterization with fewer measurement points compared to traditional step-by-step current increment methods.
Solution Approach 2:
The invention transitions from static current step measurements to dynamic measurements during motor rotation. By measuring electromotive forces during continuous rotation with varying currents, the system captures flux characteristics more efficiently, reducing the number of discrete measurement points required while maintaining accuracy.
3Manufacturing precision
If numerous measurements are taken to adapt magnetic characteristics, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The motor performs self-characterization during normal operation or production testing, eliminating the need for separate, time-consuming laboratory testing for each unit. The automated measurement system quickly determines magnetic characteristics by analyzing electromotive forces during brief operational periods, enabling high-volume production with maintained precision.
Solution Approach 2:
The method performs magnetic characteristics measurement during the motor assembly process or initial commissioning phase, rather than requiring post-assembly laboratory testing. This preliminary characterization integrates seamlessly into the production workflow, maintaining manufacturing precision while avoiding productivity losses from separate testing stages.
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 reduces costs and complexity while maintaining high accuracy, enabling efficient and automated adaptation of magnetic characteristics, suitable for industrial-scale production of three-phase synchronous reluctance motors.
Implementation Method 1
applying a predetermined number m, n of voltage and current variations to the stator with a predetermined frequency f
Implementation Method 2
determining differential inductances in response to voltage and current variations
Implementation Method 3
The motor has at least one pair of axes D, Q of minimum magnetic reluctance and maximum magnetic reluctance
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A method of automatically adapting the magnetic characteristics of a synchronous reluctance motor (2), of the type that comprises a stator (3) housing a rotor (4) therein and defining at least one pair of axes of minimum and maximum magnetic reluctance (D, Q), a control unit (5) for controlling power supply to the motor, wherein the motor has predetermined rated current (I) and rated voltage (V) values experimentally obtained on the bench, and wherein the supply current has components (id, iq) along the axes of minimum and maximum reluctance; the method comprises the steps of applying a predetermined number of voltage and current variations (dV, dl) to the stator with a predetermined frequency (f), determining differential inductances (Ldiff) in response to voltage and current variations, calculating the flux curves (λd, λq) of the motor by integrating the differential inductances (Ldiff) and mapping said curves in the control unit for automatically adapting the magnetic characteristics of the motor with substantially the same accuracy as that of an experimental test. The numbers (m, n) of voltage and current variations is relatively small as compared with the number of measurements experimentally taken on the bench.