The Magnetic-Less Single-Stage Isolated DC/AC Converter Based on Piezoelectric Transformer

This paper proposes a novel approach to enhance the performance of single-stage isolated DC/AC converters by employing magnetic-less configuration, not reported in academic publication before. Piezoelectric transformers (PTs) offer significant advantages, including high power density, and compact size compared to traditional magnetic transformers. Furthermore, the integration of these transformers within low frequency (lower than several tens Hz) single-stage PWM inverters facilitates a batch-fabricated system integration with reduced EMIs. This paper explores the design, implementation, and benefits of this integration, emphasizing its potential to meet the stringent requirements of mobile devices and communication systems, where miniaturization and reliability are most-critical factors. The paper proposes a modulation strategy based on dual phase-shift controller to extend the zero-voltage switching (ZVS) range, as well as presents a comprehensive discussion on the PT design and its equivalent circuit estimation. And also, this paper includes a development of the hardware prototype to validate the feasibility of the proposed converter. The experimental results demonstrate the potential of this magnetic-less approach as a promising solution for the next-generation power conversion systems.