Intro Consists of six semiconductor devices. Stator winding- star connected. Rotor - (RPS and TG) - to get actual speed signal. Commutation logic –info about position of rotor to turn ON and OFF the device.

Structure of Controller

Function Hall effect sensor – to sense the shaft position. Signals decoded by commutation logic – provide firing signals for 120⁰ conduction. It has six outputs to control upper & lower transistors. Programmable logic arrays, gate arrays, EPROMs can used.

Contd… PWM is applied only to lower phase leg transistors. Reduces current ripple. Avoids wide bandwidth in level shifting circuit that controls upper transistors. Upper transistors may be of different type –need is switch at commutation frequency. AND gates are used to combine commutation & chopping signals.

Contd… Output signal – conduction period and duty cycle of lower level devices. Desired current for desired speed can be achieved – brings speed control of BLPM DC motor

Thank YOU….