Magnetic Resolver Using Hall-Effect Sensors

Control of AC electric machines requires, in many cases, accurate knowledge of rotor position. Encoders and resolvers are the most widely used option in the industry. Variable reluctance (VR) resolvers are advantageous in harsh environments due to their robustness; however, they represent a significant portion of the total drive cost. This paper presents a magnetic resolver using low-cost Hall effect sensors. Advantages with conventional encoders include compactness and reduced cost, which are achieved without penalizing the other properties of VR resolvers. The proposed sensor is fully compatible with conventional drives and supports wide carrier frequency and supply voltage variations.