一种无传感器电流检测技术

A Type of Current-sensing Technique without the Current Sensor

介绍一种用半导体电子线路取代电流传感器检测功率变换器主开关电流的技术,该技术根据流过开关管的电流大小与其通态压降成正比的原理,用检测通态管压降的方法检测通态电流。分析了单相全控桥式逆变器在双极性、单极性、单极倍频等几种工作方式下开关管通态压降的表现形式及电流波形重构原理,实验结果证实该技术具有实现简单、经济实用的特点,值得推广。

A novel technique of power electronic switch current detection,in which the current-sensor is replaced by electronics circuit,is introduced in this paper.According to the principle that the magnitude of the switch current is proportional to its turned-on voltage drop, the proposed technique utilizes the method of grasping the turned-on voltage drop of the MOSFET to reproduce its current waveform.The appearances of voltage drop of the MOSFET in a single phase full-bridge under the bi-polar,single-polar and single-polar-double-frequency PWM operation modes are analyzed and the current reconstruction principles are introduced.Experimental results are given to show the proposed technique. It has the characteristics of simplicity and inexpensiveness and is worthy of adoption.