Three-mode switching control Strategy based on Two-Switch Buck-Boost converter

Abstract

The Two-Switch Buck-Boost (TSBB) converter can adjust a wide voltage range and is widely applied in the field of aerospace power supply. According to the energy relationship among the output power of the solar array, battery, and load, the converter can operate under three different modes. To solve the problem that the input voltage is clamped in the process of battery charging and the maximum power point tracking (MPPT) of the solar array is affected, a smooth switching control strategy between three modes is proposed in this paper. The operating mode of the current converter is determined by the variation of the current integral on the output capacitor, and it is used as the condition for the converter to exit the pass-through (PT) mode. In this way, the fast and stable switching between modes can be realized, and the dynamic response of the converter can be effectively improved. In addition, in order to avoid the input voltage disturbance affecting the output characteristics, this paper proposes a closed-loop control design based on input voltage feedforward control. Plecs simulation results show that the proposed loop control strategy has good stability and reliability.