In conventional BLDC motor during bipolar operation, at any time across DC bus, two phases come in series. Only half of the DC bus voltage is applied to each phase, resulting in addition of torque constant on both phases there by achieving high starting torque. But speed will be limited. To get higher speed, full DC bus voltage is to be applied to each phase. This can be achieved in unipolar operation, where each phase conducts only in one direction which in turn reduces the starting torque.Thus in order to get high torque, motor should operate in bipolar mode and to get high speed motor should operate in unipolar mode. Shifting of modes between unipolar and bipolar operation is achieved based on speed requirement. The proposed inverter consists of 4 legs. The 3 phases of BLDC motor is connected to first 3 legs and neutral point is connected to the fourth leg as shown in Figure-1. In bipolar operation first 3 legs are active and the 4th leg is inactive. Here we have considered only bipolar operation.