Modular and compact design for an isolated high-frequency-link inverter using hybrid-modulation scheme

High frequency link (HFL) power converters, due to advancements in magnetics and semiconductor devices, have been gaining considerable attention among designers and researchers. This paper presents a compact and modular isolated dc-link capacitor less HFL inverter that is suitable for renewable-energy systems. Modular three-phase insulated-gate bipolar transistor (IGBT) power modules are employed to increase the power density of the inverter. In addition, bulky dc-link capacitor is eliminated from the power stage of the inverter to achieve a compact and high-power-density design. Hybrid modulation (HM) scheme is used to decrease the switching losses of the inverter because it decreases the switching requirement of the pulsating-dc/ac converter by 66%. This paper shows that dc-link-capacitor less HFL inverter has a proper output THD over a wide range of output-load power despite that fact that it operates without any dc-link capacitors. The experimental results verify the operation of a 2 kW dc-link-capacitor less HFL inverter using the HM scheme.