New technologies for simpler adjustable speed brushless motor drives

Abstract

Recent advances in the power semiconductor technology, including developments of smart-power (High Voltage Integrated Circuits, HVICs), have a direct impact on the research and development efforts in the motor drive technology. Brushless Electronically Commutated Motor (ECM) and Switched Reluctance (SR) motor, along with their drive control systems, are being developed to satisfy the criteria of high efficiency, high reliability and enhanced performance at low cost. Efficient control techniques are developed in this dissertation for the control of brushless ECM and SR motor drives. A new current regulation technique is developed which uses current feedback information from current sensors, integrated into the new generation of MOS-gated power switches i.e., MOSFETS and IGBTs, thus eliminating the need for discrete current sensors. Algorithms are developed to cope with the lack of current feedback information when the switch is not conducting. Experimental results on a fractional ECM motor show that the new current regulation algorithm has excellent performance characteristics. It is further shown that the use of smart-power devices lead to a high level integration and protection for the ECM drives enabling operation at bus voltages up to 500 VDC with power ratings from fractional to greater than 10 HP. A novel regeneration scheme which does not require additional switches is also developed. Extensive simulation and experimental results show salient features of the fully integrated four quadrant ECM drive with current regulation. In another aspect of technology simplification for motor drives, a four-quadrant SR motor controller and its commutation schemes are developed using low resolution position feedback. Experimental results on a fractional horse power SR motor show that high performance from the SR drive can be obtained at low cost. The drive has excellent dynamic reversing capability and the required operating mode can be easily selected.