Modeling and Analysis of a Linear Resonant Electrostatic Induction Motor Considering Capacitance Imbalance

This paper reports the modeling and analysis of a linear resonant electrostatic induction motor, with an imbalance in capacitance taken into consideration. The motor is an asynchronous motor consisting of film-type stator and slider with three-phase electrodes, driven by three-phase voltage applied to the stator. The slider electrodes are connected to three coils, which enable the slider voltage to rise high at resonance, producing large thrust force. The motor is highly sensitive to an imbalance of capacitance, particularly at resonance. A model is developed to relate each capacitance formed among the electrodes to symmetrical components of the slider voltage and to the thrust force of the motor. The model indicated that the capacitance imbalance leads to an unbalanced slider voltage with two frequency components and causes thrust force ripple. These nonideal effects were confirmed by experiments, using a motor with geometric asymmetry in its electrode design.