High-Accuracy Resolver-to-Digital Conversion Based on Active Disturbance Rejection PLL

The accuracy of rotor position detection directly affects the precision and performance of the servo system. Inaccurate shaft angle transformations can lead to serious errors. Traditional phase-locked loop methods can result in significant tracking deviations in situations with high dynamic response requirements, leading to larger angular measurement errors. Dedicated shaft angle conversion chips also face issues such as high costs and complex selection of peripheral components. Therefore, to address the problem of low dynamic performance of traditional phase-locked loops due to sudden changes in motor drive system speed, there is a need to design a low-cost and high-precision all-digital shaft angle conversion strategy.This paper proposes a fully digital decoding method based on the Active Disturbance Rejection Control (ADRC) for estimating the rotational speed and angular position of the motor rotor shaft. The second-order linear ADRC technology is introduced to replace traditional PI control, and its extended state observer is used to estimate and compensate for various state variables to achieve phase locking. A novel ADRC-based phase-locked loop structure is designed. Simulation experiments demonstrate that the proposed phase-locked loop structure can effectively enhance the dynamic performance of the phase-locked loop and exhibit a certain level of disturbance rejection capability against frequency fluctuations.