Modeling and Suppression of Electromagnetic Interference Noise on Motor Resolver of Electric Vehicle

Electromagnetic interference (EMI) couplings between motor drive system and resolver circuit induce considerable EMI noise in resolver, which has a serious impact on the excitation and feedback signals of resolver. In order to suppress the EMI noise effectively, it is necessary to study the coupling mechanism between the motor drive system and the resolver circuit. In this article, an EMI estimation model of resolver is proposed. An electric vehicle motor drive system is used for analysis. Coupling effects between permanent-magnet synchronous machine and variable reluctance resolver are investigated and modeled. Impedance measurement and numerical simulation are used to extract model parameters. Based on the estimation model, the conversion of common-mode (CM) noise to differential-mode (DM) noise in resolver circuit is analyzed. The estimation model is validated by comparing simulated results and measured results. Then, a CM choke is designed in the resolver circuit to suppress the coupled EMI noise. This modeling method is applicable for analyzing the EMI noise coupling between motor drive system and other low-voltage sensitive circuits.