A Dual-Inductor-Connected Isolated DC–DC Converter With Direct Current Control and Low Current Harmonics

Abstract

Renewable energy sources such as fuel cells and photovoltaics (PV) modules are widely installed in recent years. Due to these sources’ characteristics such as low port voltage, current-harmonic-sensitive and weak short-circuit withstanding capability, their interface converters usually require high voltage gains, low high-frequency (HF) current harmonics and short-circuit protection. At present, the existing step-up isolated dc-dc converters are usually combined with two capacitor-connected terminals or one capacitor-connected terminal plus one inductor-connected terminal, failing to obtain the low HF current harmonics and convenient direct current control (DCC) on both ports. Hence, a dual-inductor-connected (DIC) isolated dc-dc converter is proposed in this paper with the inductor connection on both ports. Then, low HF current harmonics and convenient DCC capability can be realized simultaneously through the connected inductors. Meanwhile, the proposed converter can also achieve voltage spike suppression and soft-switching operation without snubber circuits, and its inherent voltage boost function makes it suitable for high voltage-gain applications. Subsequently, the modulation scheme, topology characters and control scheme are elaborated in this paper. The experimental results based on a scale-down laboratory prototype are presented to verify the steady-state and transient-state performance of the proposed converter.