Vector Control Drive of Permanent Magnet Synchronous Motor Using Resolver Sensor

The rotor position is necessary to achieve the vec- tor control drive system of Permanent Magnet Syn- chronous Motor (PMSM). In this paper, the resolver sensor detecting the rotor position of PMSM is fo- cused. The outstanding features of this sensor are its robust structure and noise insensitivity. The resolver algorithm is proposed and implemented in the vector control drive system of PMSM. The pro- posed scheme has been verifled by both simulation and experiment using MATLAB/Simulink and the TMS320F2812 based digital controller, respectively. secondary windings. The primary coil is applied by the high-frequency sinusoidal voltage in an order of kHz. Two secondary coils are placed in the stator by 90 difierences. Once the rotor is rotated, the induced voltages would be produced in the secondary coils. The amplitudes of these induced sinusoidal voltages are modulated with the rotor position. The demodu- lation technique must be designed to extract the rotor position. This demodulation process could be imple- mented on the R/D converter IC (1). This chip is designed to calculate the error between actual angle and computed angle. This angle error is controlled to zero, resulting in the computed angle converges to the actual one. However, the resolver algorithm is implemented by special IC chip which increases the overall cost. In (2), the calculated rotor angle is ob- tained by the similar method. However, the calcu- lation requires the resolver parameters, resulting in the complicated equations of the rotor angle. The phase lock loop demodulating method is presented in (3). This scheme employs the additional analog cir- cuit that requires the parameter adjustments due to the drift problems. In (4), the calculated position is basically obtained by a closed loop operation. The digital 16th-order FIR band-pass fllters (to limit the signal bandwidth) and downsamplers (to reduce the sampling rate) are incorporated in their proposed al- gorithm. Obviously, the phase lag due to the fllters is noticed in the system. The angle is needed to be compensated when implementing in the vector con- trol drive of PMSM. Also, the computation time of these fllters is signiflcantly long because of their high order structure. This may not be practical when the low-cost flxed-point digital controller is used. In this paper, the computed rotor angle is com- puted by means of the feedback loop control. The er- ror signal is introduced by the difierence of the cross product of modulated signals and measured excita- tion signal. Then, this error would be controlled by PI controller. The computed rotor angle is guaran- teed to be the actual one once the error becomes zero without usage of fllters. Thus, the delay efiects due to fllters are eliminated. The proposed resolver algo- rithm is successfully implemented in the vector con- trol drive of PMSM.