Analysis of the Position Error in Resolver-To-Digital Converter and Position Error Compensation in the Piston Power Generation System

Low power electric unmanned aerial vehicles usually adopt the integrated structure of a piston engine and a permanent magnet synchronous motor. During the operation of a piston engine, the output torque on the shaft experiences significant fluctuations, leading to variations in the generator’s speed. To effectively control the generator, it is crucial to acquire information about the motor rotor’s position and speed. Typically, rotor position information is obtained using a resolver and resolver-to-digital converter (R/D converter). However, position errors arise when tracking rapidly changing speed signals, thus diminishing the motor’s control performance. To address this issue, this study establishes a mechanism model of the resolver and R/D converter, investigates the position demodulation mechanism employed by the R/D converter, and analyzes the factors contributing to output angle lag. Building upon this analysis, a position error compensation algorithm is proposed to achieve accurate tracking of the motor rotor position even under conditions of frequent speed changes.