Improved operating characteristics of linear pulse motor using resonant current

The linear pulse motor (LPM) requires strong thrust force and smooth movement with suppression of its pulsation and pulling-out. To respond to these requirements, several methods have been reported. But there are some defects such as large power loss, complicated additional circuits, deterioration of thrust force characteristics at high operating speed and so on. This paper describes the new control circuit improving these defects, in which the variable capacitor or switched variable capacitor circuit is connected with a motor winding in series. This capacitor is controlled to maintain the resonant condition that is achieved by the capacitor and the inductance of the motor windings, and this circuit makes the exciting current waveform sinusoidal. It is confirmed that the resonant current of the sinusoidal waveform causes the smooth movement and improves the thrust force characteristics over the wide range of pulse rates