A Power Allocation Method for Semiactive Battery–Supercapacitor Hybrid Power Supply System for Electric Aircraft

Abstract

Electric aircraft is an important development direction for the future aviation industry, but it is currently constrained by the energy density, power density, and reliability of energy storage devices. Therefore, a battery-supercapacitor (SC) hybrid power supply system (HPSS) is a promising architecture. The traditional power allocation strategy for a semiactive battery-SC HPSS suffers from unclear high- and low-frequency band boundaries, frequent reaching of upper and lower thresholds of the SC state of charge (SoC), and inadequate control over the bus voltage. To solve these problems, this article proposes a power allocation method with SC’s SoC self-recovery and dc bus voltage-assisted regulation. This method takes advantage of the characteristics of the second-order filter to realize the self-recovery of the SC’s SoC after the transient and avoid the frequent reaching of upper and lower thresholds. It also constructs a control loop of the current outer loop-voltage inner loop to achieve auxiliary regulation, as well as the support of the SC for the dc bus voltage. The proposed method enhances the operational continuity of the power supply system, avoids frequent mode switching, and improves system safety. The experimental results validate the feasibility and effectiveness of the proposed control method.