Unified Inductor Type Based Linear Resonant Hybrid Converter for Wide Voltage Range Applications

Pulse frequency modulation (PFM) is widely used in LLC resonant converters. However, in wide voltage applications, the switching frequency range is very wide, which affects the performance of magnetic components and filters. In order to achieve wide voltage gain in a narrow frequency range, this paper proposes a unified inductor type based linear resonant hybrid converter (UITBLRHC). The resonant inductor and excitation inductor are unified, and the resonant tank with equal inductance ratio is achieved. Hence, the output voltage can be adjusted within a very narrow frequency range. In addition, the parameters and operating modes of the two inductors are exactly the same. Therefore, the types of inductors can be reduced, and the magnetic flux and heat distribution between the two inductors are more uniform. Finally, an 800 W prototype was built. The proposed solution can achieve twice the voltage gain within a frequency range of 1.25 times. The experimental results prove the reliability and validity.