基于半PWM移相的单电阻电流重构策略研究

Research on Single-shunt Current Sensing Method Based on Half PWM Phase Shift

单电阻电流重构策略存在两个观测盲区:低调制度区域和扇区过渡区域。通过对PWM脉冲信号进行修正可以解决观测盲区内的最小采样时窗问题,实现有效的电流重构。传统的PWM脉冲的修正策略虽然解决了非观测区最小采样时窗不满足要求的问题,但是也导致了电流纹波的增大。在分析传统策略的基础上,提出了一种基于半PWM移相的电流重构策略,可以有效的改善由于PWM脉冲修正带来的电流纹波问题。仿真及实验结果表明:基于半PWM移相的单电阻电流重构策略可以有效地降低重构电流纹波,具有良好的重构效果。

The single-shunt current reconstruction strategy has two blind areas:low modulation area and sector transition area. By modifying the PWM pulse signal, the problem of the minimum sampling time in the blind areas can be solved, and effective current reconstruction can be realized. Although the traditional PWM pulse modifying strategy solved the problem that the minimum sampling time in blind areas, it also led to the increase of current ripple. Based on the analysis of traditional strategies, a new strategy was proposed, which can effectively improved the current ripple problem caused by PWM pulse modifying method. Simulation and experimental results show that the proposed strategy can effectively reduce the current ripple and has a good performance.