Analysis and Optimization of GaN-Based AC-DC Converters for Enhanced ZVS Performance

Abstract:
Resonant-based power converters are widely adopted due to their ability to achieve high efficiency through soft switching techniques, particularly zero voltage switching (ZVS). However, these converters often require additional components such as inductors, capacitors, transformers, diodes and active switches, which complicate the design and increase the size of the converter. This paper investigates the conditions for naturally achieving ZVS in a GaN-based Power factor correction or boost converter, utilizing parasitic capacitance of switch and boost inductor, reducing switching losses and EMI while enhancing power density and efficiency. The paper proposes a technique that ensures ZVS without adding any additional components even when inherent conditions are not satisfied, by driving the input inductor current negative before turning off the high-side switch. The proposed methodology is validated through comprehensive mathematical analysis, and experimental results and compared with normal MOSFETs using simulations demonstrating its effectiveness in enhancing converter performance.