Voltage Feed-Forward Control of Photovoltaic- Battery DC Microgrid Based on Improved Seeker Optimization Algorithm

The photovoltaic-battery DC microgrid is a new type of power system supply architecture that can effectively utilize renewable energy and is suitable for modern DC electrical equipment. In this paper, a fast and efficient maximum power point tracking (MPPT) photovoltaic (PV) control method and a battery energy storage system (BESS) bus control method are proposed to improve the PV utilization and the bus voltage performance. Firstly, the principle of photovoltaic-battery and power balance is analyzed, and the mathematical model of each distributed generation in the DC microgrid is derived. Secondly, by introducing the voltage increment and time-varying smoothing factor, the exponential variable step perturbation and observation method for PV controller is proposed to accelerate the MPPT process. Considering the intermittent disturbance of PV energy absorption and large power fluctuation on the DC bus, parameters of BESS voltage controller are optimized by the improved seeker optimization algorithm (ISOA) which is improved by the variational Cauchy operator and chaotic initialization optimization strategy. Furthermore, to improve the voltage closed-loop response speed and reduce the hysteresis characteristics, a feed-forward compensation strategy is designed. Finally, multi-scheme simulation analyses are implemented in MATLAB/Simulink. Compared with the simulation results of traditional control method, the proposed method reduces the average voltage ripple percentage from 3% to 1% and improves the MPPT response speed from 70ms to 10ms. The simulation results verified the correctness and effectiveness of the proposed method.