Electromagnetic Compatibility Analysis and Optimization of a Resolver for Measuring the Angular Displacement in High-Power Synchronous Motor

As a high-precision measurement device of angular displacement and angular velocity, the stability and robustness to harsh environments make resolver the first choice for many rotating equipment monitoring systems, which plays a vital role in a variety of industrial applications. However, in fact that the resolver is essentially a sensor in compliance with the principle of electromagnetic induction, which means that its performance is affected by the complex electromagnetic environment in the presence of multiple potential sources of interference. In this paper, a sine-cosine resolver of Model SG110-XXV1 is applied to a high-power synchronous motor, and induced voltage of the resolver appears to be distorted during the experimental process, which affects the measurement accuracy of angular displacement and the control operation of motor. In order to accurately determine the source of interference and find an effective solution, this paper establishes a complete set of Electromagnetic compatibility (EMC)analysis process and test system. After the spectrum analysis of distorted waveforms, the results show that excessive armature magnetic field and excitation magnetic field of motor will have an impact on the resolver, the baseband frequency related to rotational speed is out of range, which should take certain solutions such as designing a corresponding filter to eliminate interference. After the implementation of the proposed solution, the completeness of the analysis process and the effectiveness of the solution are confirmed through experimental verification, which not only restores the normal output signal of resolver, but also forms a complete closed-loop control system between the high-power synchronous motor and the resolver, which ensures the stable operation and great dynamic performance of the system.