Flux-Rate-Controlled Adjustable Inductor for DC-DC Converter and Dynamic Load Impedance Variation Applications

This work proposes a specific approach to regulate the inductance value smoothly using a flux-rate-controlled adjustable inductor. The proposed adjustable inductor comprises a commercially available three-limb core, two windings, and a control switch, which gives a low-cost solution. The control switch is realized using a bidirectional switch or a variable resistance. The duty ratio or the variable resistance value controls the flux-rate to adjust the inductance value. The proposed adjustable inductor is modeled using the widely used bond-graph technique to perform the simulation study. The working of the adjustable inductor is validated through several applications explained in this work. The experimentation for the dc load impedance variation application is conducted using a laboratory-built prototype considering both methods of flux-rate control. The inductance values obtained from the experiments follow the simulation study’s calculated values. The ac load variation experimentation is performed at 500 Hz to observe the change in phase angle due to the inductance variation. This work integrates the proposed adjustable inductor with dc-dc converters to enhance the continuous conduction mode (CCM)–discontinuous conduction mode (DCM) regions. A basic PI controller performs the closed-loop control of the SiC-based synchronous buck and boost converters to validate the system stability during inductance variation.