Direct Use of Bridgeswitch Current Sense Signal Output in Field Oriented Control of Brushless DC Motors


High performance motor drives commonly use field-oriented control (FOC) since it offers smooth and efficient operation throughout the entire speed range. BridgeSwitch offers a unique function by providing a small signal output that is an instantaneous representation of the positive phase current. This function can eliminate commonly used discrete current sense resistors and associated amplifiers, thereby reducing cost and design complexity. This document presents a proposed algorithm that allows using the small signal output provided by each device through directly measuring, reconstructing, and predicting the full phase current information in 3-phase motor drives utilizing FOC where the motor provides the rotor position information.