This paper presents a high-efficiency inverter with the aid of the soft-switching technology, which is accomplished by the resonance of the in-series inductance with the snubber capacitance. The equivalent circuit of the quarter-phase ultrasonic motor is initially deduced, based on which the topology along with the operations of the novel inverter is subsequently presented. The configuration of the new quarter-phase inverter shows its uniqueness in terms of the shared arms and the especially designed snubber capacitance in comparison with the existing inverters. The circuit analysis infers that the dead time of the inverter is the key factor to arrive at the zero-voltage-switching or the zero-current-switching operations. Experimental measurements have demonstrated that the efficiency of the whole drive increases by a factor of 1.25 after replacing the traditional inverter with the proposed one. It should also be noted that the proposed inverter in association with the design method of the dead time not only can work for the quarter-phase ultrasonic motor, but also can be applicable for other kinds of quarter-phase devices. The soft-switching operations are achieved in the quarter-phase inverter for the first time, whose amplitudes of the output voltage and switching frequency are not required to be constant any more.

中文翻译：

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用于四分之一相超声波电机的具有软开关能力的伪全桥逆变器


本文提出了一种借助软开关技术的高效逆变器，该技术是通过串联电感与缓冲电容的谐振来实现的。最初推导了四分之一相超声波电机的等效电路，随后介绍了新型逆变器的拓扑结构和操作。与现有逆变器相比，新型四分之一相逆变器的配置在共享臂和专门设计的缓冲电容方面显示出其独特性。电路分析得出逆变器的死区时间是实现零电压开关或零电流开关操作的关键因素。实验测量表明，用所提出的逆变器替换传统逆变器后，整个驱动器的效率提高了 1.25 倍。还应该注意的是，所提出的逆变器结合死区时间的设计方法不仅可以适用于四分之一相超声波电机，而且还可以适用于其他类型的四分之一相装置。首次在四分之一相逆变器中实现了软开关操作，其输出电压幅值和开关频率不再要求恒定。