A Bus Clamping PWM-Based Improved Control of Grid Tied PV Inverter with LCL Filter Under Varying Grid Frequency Condition

This paper presents a modified Synchronous Reference Frame Phase locked loop (MSRFPLL) for better synchronizing the output of the inverter with the grid. The proposed PLL is able to track the changes in the grid frequency in a faster way as compared to the conventional synchronous reference frame PLL (SRF-PLL). In order to switch the inverter, an advanced bus clamping based space vector PWM is being used which is novel for photovoltaic application. This PWM gives better DC bus utilization as compared to the conventional Sine PWM technique. To keep the THD within a permissible limit of 5% in accordance with the IEEE-519 & 1547 standard LCL filter with passive damping is implemented. DSPACE-1104 DAC card has been used for better interfacing of the experimental set up with MATLAB. The overall system is also being simulated in MATLAB/Simulink environment and the simulated results have been validated with the experimental results.