An open-loop digital solver of shaft angle based on DSP

Resolver is widely used in harsh environments for its excellent antijamming capability. For the issue that conventional resolver-to-digital conversion chip cannot solve shaft angle in high-temperature drilling environment, an open-loop digital solver is proposed in this paper based on a high-temperature DSP (Digital Signal Processor). The basic solving principle of resolver using arctangent function is described. Furthermore, the process of excitation (carrier) signal generating of resolver and synchronous sampling are presented. Finally, an error compensating is implemented for improving accuracy of solver comparing with a 17bits photoelectric encoder. Experimental results show the error of the proposed digital solver is within 40′, which is small enough satisfying the requirements of measuring accuracy in oil drilling areas.