Grant: Idea to Innovation

The Hall-sensor-controlled brushless DC (BLDC) motors are increasingly used in electromechanical actuation, automation, instrumentation, and many servo applications (where the sensorless control may not always be effective), in defense and commercial industries. As low-cost/low-precision BLDC motors are becoming widely available on the market and there is a growing trend to expand their use to a larger number of applications. However, such motors tend to have significant errors in the alignment of the Hall sensors and/or the magnet with which they react. This causes unbalanced operation of the motor inverter, with some phase(s) conducting for longer and other phase(s) conducting for shorter time intervals. The resulting unbalance among the motor phases leads to adverse phenomena such as increase in torque pulsation, vibrations, acoustic noise, and reduces the overall electromechanical performance. The aim of this proposal is to develop and demonstrate fully-functional prototypes of the UBC-invented technology for improving operation of widely-used Hall-sensor-controlled brushless motors that may have almost arbitrary errors in the Hall sensor signals and enabling reliable operation with up to two faulted sensors. Our approach is based on digital filtering of the Hall-sensor signals and reconstructing the modified signals that are "free from defects" and used to control the inverter transistors with improved accuracy and reliability. The proposed filter can be deployed in many existing motor drivers and/or realized on a separate chip-dongle for inserting between the BLDC motor and its driver. The technology is relatively low-cost (0.1 - 2% of the total cost) and at the same time very effective. A preliminary analysis indicates that a cost benefit of 50 to 100% may be achievable since the filter relaxes the Hall-sensor tolerances allowing for cheaper components/manufacturing while increasing the fault-tolerance of the motor-drive system. We believe that once demonstrated, this technology will attract Canadian and international companies and subsequently become adopted by the industry worldwide.