Four-quadrant sensorless brushless ECM drive

A four-quadrant brushless electronically commutated motor (ECM) drive is presented which provides high-quality torque control without discrete current sensors or a rotor position sensor. Rotor position feedback is developed by extracting sufficient information from the motor back-EMF voltage waveforms, and current feedback is provided by current sensors integrated into MOS-gated power switches (MOSFETs or IGBTs). Controller parts count is minimized using a custom VLSI chip which performs the rotor position sensing, pulse-width-modulated (PWM) current regulation, and various protection functions. The interface between the low-power logic and inverter power switches is accomplished using a high-voltage integrated circuit (HVIC) gate-driver for each of the three phase legs. Experimental results using a compact prototype ECM drive card are presented which demonstrate the desired four-quadrant performance without discrete sensors