Variable-Carrier-Based PWM Control of Hybrid Energy Storage System for More Electric Aircraft

The hybrid energy storage systems (HESSs), often configured with battery and supercapacitor (SC) combinations, can effectively regulate power imbalances between generation and loads within more electric aircraft (MEA) dc microgrids. However, traditional control exhibits limitation in precisely tracking high-frequency components within SC current loop. To address this deficiency, this article proposes a novel current control strategy enhancing SC current tracking capability in HESS. Departing from conventional approaches, the proposed strategy eliminates the proportional-integral (PI) controller from the SC current loop, instead integrating SC current regulation with pulse-width modulation (PWM) to form a modified PWM unit. Consequently, the input signal of this modified PWM unit derives from given function of the SC current, while the amplitude of the PWM carrier signal is reformulated to vary instantaneously with the SC current. The variable-carrier-based PWM method accelerates the realization of SC current synthesis. Furthermore, a small-signal model is also explored to deeply investigate the stability of the HESS. Subsequent simulations are conducted to verify the performance across multiple scenarios. Experimental validation conducted on a 25 kW HESS power stage demonstrates the theoretical feasibility of the proposed control methodology.