Charge-Discharge Cooperative Control Strategy for Hybrid Energy Storage System Based on MPC

The intermittent nature of renewable energy generation renders DC microgrids (DCMGs) susceptible to multi-timescale power mismatches and voltage instability within the DC bus network. Hybrid energy storage systems (HESS) integrating batteries with supercapacitors are capable of alleviating power fluctuations and enhancing system stability. To optimize photovoltaic (PV) power utilization and enhance the collaborative performance of HESS, a HESS charge-discharge cooperative control strategy based on MPC is proposed to stabilize the power fluctuation of PV power. Firstly, in order to improve the accuracy of MPC prediction model, a short-term power prediction model of photovoltaic power based on intelligent algorithm is constructed. Then, to tackle the issue of conflicting charge-discharge behaviors between batteries and supercapacitors, a timing-based coordinated control strategy is developed to adjust the initial power allocation of the two energy storage devices. Finally, a model predictive control based on pulse width modulation (PWM-MPC) is proposed for energy storage converter. In addition, in order to eliminate the steadystate deviation caused by modeling parameter errors, an error compensation mechanism is proposed to reduce the steady-state deviation of the DC bus voltage.