Phase current sensing technique for two-phase three-leg inverters using three shunt resistors

This paper presents a current sensing technique using three shunt resistors in a three-leg inverter for operating of two-phase motors. Hall-effect sensors are unsuitable for current sense in cost-sensitive two-phase inverters due to their high price. Three shunt resistors are used to replace these sensors and placed between the lower switches and the negative dc rail, as in three-phase inverters. Current sensing capability of three-leg inverter with three shunts is investigated on voltage vector plane. The two-phase currents are measured on two shunts of phase legs and reconstructed by utilizing an additional shunt resistor of neutral leg in certain immeasurable area. Simulations and experiments are conducted to validate current sensing technique using three shunt resistors in two-phase three-leg inverter.