Feedforward Speed Control of Brushless DC Motors with Input Shaping

The objective of this work is to apply feedforward control to a brushless direct current motor (BLDC) using input shaping method to achieve speed control with fast transient. It is shown that the hardware requirement is minimal and the existing Hall sensors are sufficient. However, due to the sensor quantization effects, output ripple attenuation is necessary. The use of low bandwidth control removes output ripples from the low resolution sensor while the use of a shaper improves the transient performance of the overall system. The input shaper is particularly suitable in this application since it is an open loop algorithm, independent of the sensor characteristics. Virtual instruments (VIs) are then built in LabVIEW to implement the control algorithms. Experimental results confirm that the effectiveness of the proposed low bandwidth feedback/input shaping control with low resolution sensors.