New simplified energy flow management algorithms for a DC bus-coupled photovoltaic-grid hybrid system
摘要
This paper presents a new simplified linear self-adjusting algorithm and an improved artificial ant colony self adjusting algorithm, for optimal energy flow management of a photovoltaic-grid hybrid energy system coupled through a DC link. The two proposed algorithms rely on the voltage error in the stabilization of the AC link to self determine a compensation current and hence power deficit, which is automatically extracted from the back-up storage to maintain an uninterrupted service and ensure the balance between power production and consumption. Numerical simulation results in Matlab/simulink under different scenarios show the effectiveness of the algorithms in mitigating the challenges posed by the intermittent nature of the photovoltaic source and also in facilitating the rapid and flexible integration of the renewable energy source. The algorithms also contribute effectively in regulating the AC bus voltage and in maintaining the frequency and total harmonic distortion within acceptable standards. The specificity of the two proposed algorithms is the fast response speed of the system in balancing power output and consumption. A comparative study of the proposed algorithms with a proportional integral (PI) controller under different operating modes clearly show the superiority of the new linear self-adjusting algorithm in terms of system stability, response time, error reduction and total harmonic distortion mitigation.