Implementation of Isolated Two Inductor Boost Converter for Induction Motor Drive Applications

This paper proposes modified two inductor boost converter (TIBC) along with a three-phase inverter circuit for induction motor drive application. The modified TIBC is for the first stage of DC/DC converter. The input current is distributed through two boost inductors having its current ripple amplitude halved at the twice of PWM frequency. The voltage doubler is applied to reduce turn’s ratio of the transformer. This work is further improved with non-isolated recovery snubber with constant duty cycle control to improve its efficiency. The main reason of using snubber, TIBC, is not suitable for motor drive system. The reason is motor demand low power at low speed and during start up and stop conditions. Moreover, TIBC requires minimum operation load to maintain an output voltage, i.e., below certain load condition energy transferred to output capacitor is not completely transferred load causing an increase in output voltage, because the inductors are charged even if there is no output current. TIBC is able to turn on both the active switches at zero voltage to reduce their switching losses and raises the conversion efficiency. Since the two parallel-operated boost units are identical, operation, analysis, and design for the converter module becomes quite simple.