A Review of Variable-Inductor-Based Power Converters for Eco-Friendly Applications: Fundamentals, Configurations, and Applications

Modern eco-friendly industries such as renewable energy systems, electric vehicles (EVs), and light-emitting diodes (LEDs) have led to technological advancements in power electronics. Switching-based power converters have limited working ranges and can cause significant harmonics and oscillations in the output voltage and current. Introducing variable inductors can help solve this problem by changing the inductance without resorting to extreme switch duty cycles. Despite their advantages, there is still a lack of comprehensive reviews of variable inductor applications in power converter design. A thorough and in-depth review of variable inductance control in power conversion is presented, including its significance, working principle, core structure, modeling method, and typical applications. Traditionally, an inductor works in its linear magnetic region; its inductance in a power converter is considered constant, and the converter operates under fixed working conditions. However, a broad range of working conditions is required for power converters in practical applications. This is typically realized by changing the duty cycles of the switches. The working principle of variable inductance is reviewed, and the application of variable inductance control in power converters is presented, which will further help power electronics researchers and engineers design flexible and resilient power converters.