Natural‐air‐cooled 5 kVA single‐phase GaN inverter with paralleled multilayer PCB magnetics

Abstract

In this study, a systematic approach to the design and development of a high-efficiency, natural-air-cooled, single-phase inverter with a multilayer high-current printed-circuit board (PCB) magnetics is presented. The size and efficiency of inverters implemented with the silicon transistor technology have almost reached a certain limit. The use of wide bandgap power semiconductors, such as the silicon carbide metal–oxide–semiconductor field-effect transistor and the gallium nitride (GaN) enhancement-mode (e-mode) transistor not only pushes further the efficiency limits, but also shrinks the inverter size. A new approach is proposed here in order to obtain a high-efficiency inverter which relies basically upon the derivation of analytical expressions for the inverter losses as a function of the inverter modulation index, for the optimum transistor and highest switching frequency pair selection, and the design of the output filter based on a paralleled, multilayer PCB magnetics. In the developed 5 kVA single-phase full-bridge inverter, GaN e-mode transistors are used to minimise the inverter losses and to decrease the cooling requirement, and size of the system. The proposed systematic design approach has been verified on the implemented 5 kVA, 50 kHz, naturally-cooled GaN inverter, with a power density of 2.7 W/cm 3 (44.3 W/inch 3 ), and a full-load efficiency of 98%.