IMPLEMENTATION OF SENSORLESS POSITION DETECTION CIRCUIT WITH FOUR-SWITCH INVERTER TOPOLOGY FOR A PERMANENT MAGNET SYNCHRONOUS MOTOR

Abstract

Applications using permanent magnet synchronous motors (PMSM) are becoming increasingly popular today. These motors are controlled by special electronic circuits; with the advances in semiconductor technologies, they have acquired more specialized and extensive application areas. In this study, the sensorless position detection was performed with six step control of a PMSM / BLAC motor using four switch inverter topology. In the method that used, as the necessary commutation points for motor driving are obtained directly at the developed circuit output, the 30 degrees electrical phase shifting was not required, as in the methods based on the back-EMF voltage. Shifting is performed depending on delaying of the filters adapted to the circuit and the motor speed. The motor terminal voltages are used in the application with respect to the ground point of the circuit without the need for a motor neutral point. Thus, when the PMSM / BLAC motor is driven by four switches and six step control, sensorless position detection is performed to provide position input to the closed loop speed control with fewer circuit components, less drive complexity and cost effectiveness.