A Novel Open-Loop Inductosyn Angle-Measuring System Based on Synchronous Sampling and Definite Integral

As a high-precision position sensor, inductosyn is mostly used in high-performance control algorithms such as modern motor drive systems. For the two-phase input single-phase output mode of inductosyn, the conventional method can only calculate the angle through a closed-loop method, which has high accuracy but poor dynamic characteristics, and the two-phase input single-phase output structure lacks an open-loop angle calculation method with faster response speed. In order to solve this problem, this article proposes an open-loop angle calculation method for two-phase input single-phase output structure. First, a strategy to extract two sine and cosine signals from the single output signal based on synchronous sampling is proposed, and then, the quantization errors of the sampling signals are reduced by a definite integral method. Finally, the angle can be obtained through lookup table method. The experimental results show that the open-loop method can effectively improve the calculation speed, has better dynamic characteristics than the conventional closed-loop method while maintaining high accuracy, and is suitable for scenarios with frequent speed variations.