Flux-Rate Controlled Harmonic Filtering of an Integrated Magnetics-Based Isolated Single-Phase Inverter Topology

Modular converters are becoming popular day by day for medium to high-voltage applications. This work proposes a flux-rate controlled harmonic filtering of an integrated magnetics-based isolated single-phase inverter topology. The presented system consists of a high-voltage, high-power main inverter and a low-voltage, low-power control inverter. The main inverter performs a square wave mode of operation throughout the complete operating range at the fundamental operating frequency to set up the primary flux in the magnetic circuit. The fundamental subtracted pulse width modulation (FSPWM) drives the control inverter to perform the flux-rate control operation in the magnetic circuit. The load is connected directly to a galvanically isolated port of the magnetic circuit. The flux-rate control operation in the magnetic circuit makes the proposed inverter's output port free from power electronics components and filtering requirements. The proposed inverter system performs a linear operation throughout the entire operating range. These attributes of the proposed scheme enable the scheme's usage in medium to high-voltage applications. Even in these applications, the power semiconductor device ratings remain unchanged irrespective of the load voltage requirement. The operation of the proposed inverter scheme is validated using analytical calculations and simulated results, and finally, experimentation is performed using a lab build prototype. This study compares the proposed scheme with the conventional isolated single-phase inverter system in terms of power loss, area product, and the number of turns.