Experimental prototype of a novel feed forward compensation for DC‐link voltage stabilization in grid‐tied PV system

摘要

DC-link voltage control is an eminent attribute of grid-tied photovoltaic (PV) systems, and it is maintained at 10% to 15% higher than the peak of supply voltage to control the flow of active power. However, large variations in amplitude of supply voltage, compensating current, and PV current affect the recital of DC-link voltage controller, which further deteriorates the performance of control algorithm. This paper presents a small signal analysis using instantaneous power balance on both sides of inverter for DC-link voltage stabilization. A novel feed forward compensation (FFC) technique is proposed for mitigating the effects of external disturbances. Active current detection technique is also proposed for load current decomposition and compensating current detection which is needed for FFC technique design. An integral time absolute error criterion is used for collecting the error generated by the floating nature of DC-link voltage reference. This generated error is minimized by optimal tuning of the proportional controller using gravitational search algorithm. The effectiveness of the proposed controller is validated using sensitivity analysis. The dynamic performance of the proposed control technique is tested and verified using MATLAB/Simulink. Hardware prototype using a cost-effective Arm Cortex M4 microcontroller (STM32F407VGT6) is also presented to validate the simulation results.