A Multi-Objective Adaptive Switching Control for Bidirectional DC/DC Converter

This paper proposes a multi-objective adaptive switching control (MOASC) for bidirectional DC/DC converters (BDC) in a dc microgrid (DCMG) with a photovoltaic unit (PV) and energy storage (ES). It seeks to realize rapid switching of control objectives and smooth the transient process during bus voltage drop and restoration. MOASC consists of three steps, namely PI calculating, decision-making and synchronous updating. Multiple single closed-loop PI controllers simplify the control structure. Starting from the gain characteristic of a BDC under two configurations, a hierarchical judgement, which is equivalent to the double closed-loop controller, is presented to obtain the duty cycle to control the main switch. To avoid integral saturation and enhance the control performance, the integral term of each loop is updated periodically. The stability of the MOASC is analyzed by mathematical analysis and building transfer functions with variable parameters. Comparative experiments are designed to verify the feasibility and superiority of the MOASC. The response speed and transient performance during objective switching is improved.