Effect of Current Measurement Timing and Antialiasing Filter in a Single-Phase Inverter

Synchronous current measurement is a standard method for digital inverter control. Conventionally the measurement is sampled at pulse-width modulation carrier peaks to provide an average value of the current over the modulation cycle. With increased switching frequencies of inverters, the accuracy of the current measurement may suffer, especially during short output voltage pulses at high duty cycles. This paper focuses on the effect of sampling instant timing of the current measurement of a single-phase H-bridge inverter. Experimental tests show that proper analog to digital conversion timing and antialiasing filter design will significantly improve the current measurement accuracy.