Title :
DSP-based resolver-to-digital conversion system designed in time domain
Author :
Hou, Chung-Chuan ; Chiang, Ying-Hsuan ; Lo, Chi-Pong
Author_Institution :
Dept. of Electr. Eng., Chung Hua Univ., Hsinchu, Taiwan
Abstract :
Resolver is an absolute angle measurement and is mounted on the motor shaft to acquire the motor´s absolute angular position. This study presents an equivalent circuit of the resolver neglected rotational back electromotive force. The transfer function of the resolver is derived from the equivalent circuit. The frequency response of the resolver is measured by a dynamic signal analyser to obtain the adequate frequency of resolver´s reference signal. Furthermore, a digital signal processor (DSP)-based resolver-to-digital conversion system is designed in time domain. A pulse signal generated by the DSP is utilised as a reference signal coupled into the resolver´s rotor winding and provides primary excitation. The sine and cosine modulated output signals are sampled by the analogue-to-digital converter of the DSP within 1 μs. The sampled frequency of outputs signals are the same frequency as the pulse signal. The angular position is derived by the inverse tangent of the quotient of the demodulated sine and cosine samples. Test results are presented to validate the performances of the proposed scheme.
Keywords :
analogue-digital conversion; angular measurement; digital signal processing chips; electric motors; electric sensing devices; equivalent circuits; machine windings; position measurement; rotors; shafts; DSP-based resolver-to-digital conversion system; analogue-to-digital converter; angle measurement; cosine modulated output signals; digital signal processor; dynamic signal analyser; equivalent circuit; frequency response; inverse tangent; motor absolute angular position; motor shaft; pulse signal; resolver neglected rotational back electromotive force; resolver reference signal; resolver rotor winding; sampled output signal frequency; sine modulated output signals; size 1 mum; time domain analysis; transfer function;
Journal_Title :
Power Electronics, IET
DOI :
10.1049/iet-pel.2013.0502