IMPLEMENTATION OF SOGI-PLL ALGORITHM FOR SINGLE PHASE GRID CONNECTED INVERTERS BASED ON FIXED-POINT ARITHMETIC

The tracking performance of a phase-locked loop (PLL) algorithm in grid-connected power electronic systems significantly contributes to the success of grid synchronization. This paper presents an efficient software realization of SOGI-PLL (second order generalized integrator – phase locked loop), as one of the most popular single-phase grid synchronization strategies in practice. The utilization of floating-point processors has been relatively common; however in this work, the SOGI-PLL is implemented using the fixed-point arithmetic technique in consideration of delivering a low-cost and compact hardware solution. Fixed-point microcontrollers or DSPs are still widely used by many researchers, developers, and practical engineers due to their cost-efficient implementation in both hardware and development software tools. In this work, the implementation of the SOGI-PLL algorithm in fixed-point arithmetic is demonstrated using C programming in a low-cost 16-bit fixed-point DSC dsPIC30F3014 with a 20 MHz crystal clock. Based on the implementation results, the developed SOGI-PLL algorithm can accurately estimate the grid’s fundamental voltage parameters such as the voltage magnitude, phase angle, and frequency.