Current Sampling Gain and Delay Compensation via Dummy Load
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Solution Overview
Problem
Current methods for compensating current sampling gain and delay in three-phase current sensors for permanent magnet synchronous motors are inefficient, requiring high power and time costs due to direct motor load calibration, which affects sampling accuracy and stability, especially at high speeds.
Innovation Solution
A method and system using a dummy load formed by three-phase inductors with star connection and software-generated virtual rotation angle for simultaneous current sampling gain and delay compensation, decoupling the compensation processes through closed-loop voltage feedbacks, allowing for accurate and consistent current sampling without active power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct motor load calibration is used for current sampling delay compensation, then compensation accuracy is improved, but power cost and time cost increase significantly
Solution Approach 1:
The patent introduces a dummy load (resistive load) as an intermediary device to replace the motor for calibration experiments. The dummy load allows current sampling delay compensation to be performed without actually running the motor, thereby achieving compensation accuracy while avoiding high power consumption and time costs associated with direct motor load calibration.
Solution Approach 2:
The patent creates a simplified copy of the actual motor operating condition by using a dummy load that mimics the electrical characteristics without the mechanical complexity. This copying approach enables the calibration process to be performed on a static electrical model rather than requiring actual motor operation, reducing power and time costs while maintaining compensation accuracy.
2Measurement precision
If direct motor load calibration is used for current sampling gain compensation, then compensation accuracy is improved, but time cost and space cost increase
Solution Approach 1:
The dummy load serves as an intermediary that enables gain compensation calibration without requiring actual motor operation. This approach achieves accurate gain compensation while significantly reducing the time cost compared to direct motor load calibration, as the dummy load can be calibrated quickly without waiting for motor startup, acceleration, and stabilization.
Solution Approach 2:
The patent performs current sampling compensation calibration in advance using the dummy load before actual motor operation. This preliminary action ensures that compensation parameters are pre-adjusted and stored, eliminating the need for time-consuming on-site calibration during motor operation or production testing.
3Measurement precision
If separate compensation processes are used for gain and delay, then compensation thoroughness is improved, but system complexity increases
Solution Approach 1:
The patent merges the gain compensation and delay compensation processes into a single integrated calibration routine using the dummy load. Both compensation parameters are adjusted and stored together in one calibration sequence, achieving thorough compensation while simplifying the overall system by avoiding separate complex calibration systems for each parameter.
Data Source
AI summary
A method and a system for simultaneously realizing current sampling gain and delay compensation. A dummy load is formed from three-phase inductors with star connection to replace a motor load, and a dummy rotation angle is generated by software. In a calibration mode, a standard current sampling element is used for current sampling, and the related calibration parameters in the stable state are stored. Then, in a regulation mode, other current sampling elements produced in batches are used for current sampling, and the delay compensation coefficient and gain compensation coefficient of the sampled current are generated through two closed-loop voltage feedbacks respectively, and the two compensation processes are decoupled from each other and do not affect each other. The present disclosure effectively ensures the accuracy and consistency of current sampling.