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This paper presents a demodulation technique for amplitude modulated signals from a resolver based on amplitude detection of a sinusoidal waveform by numerical integration. The proposed technique performs synchronous integration on output signals of the resolver. The integration period is determined from zero crossing detection of the same output signals. The actual envelopes of the signal waveforms are obtained by utilizing the phase relationship of the integrated waveforms with the delayed carrier signal. Due to integration, the noise and disturbance effects are averaged out and the achievable accuracy is improved without applying filters. The method is developed from exploration of detecting HDD spindle rotor position in high resolution. The effectiveness of the proposed technique is demonstrated with the simulations and compared to the other methods. Experimental results are also provided to support the proposed method. [ABSTRACT FROM PUBLISHER]

The optimal drive current can reduce both the torque ripple and power loss in driving the permanent magnetic (PM) AC motor. This paper presents an analytical model for calculating the optimal drive current of the PMAC motor with surface mount PM rotor. Both the motors with and without the neutral line are analyzed. Theoretical analysis shows that, when the back-emf of the windings contains triple order harmonics, the neutral line of the motor can let the optimal drive current be different from the one without the neutral line, and it can also make the optimal drive current be more effective in the loss and torque ripple reduction. Two spindle motors are used in the analysis to show the influences of the optimal model presented. [ABSTRACT FROM PUBLISHER]

This paper analyzes the incline unbalanced magnetic pull (IUMP) generated in the permanent magnetic synchronous motor (PMSM) with the rotor misalignment. The motor magnetic field in such a motor is asymmetric, and both the magnitude and the action point of UMP vary in motor operation. This paper presents an analytical model for analyzing the 3-D effects of the UMP induced by the misalignment rotor. The numerical simulation results prove the effectiveness of the proposed analytic model. [ABSTRACT FROM PUBLISHER]