Alleviation of Lower Order Harmonics in a Single Phase Photo Voltaic Inverter Connected To Grid
Generally the Power circuit topology of the single phase PV system will be a good choice for low-rated photo voltaic inverters of rating less than a kilowatt. In the ideal case the system will not have any lower order harmonics. However, some dominant factors result in lower order harmonics in the system such as on-state voltage drops across the switches and the distortion in the grid voltage itself etc. This dc injection into the primary of the transformer will result in even harmonics which are being drawn from the grid, again providing a lower power quality. In this work, a single-phase grid-connected photovoltaic inverter topology consists of a boost section, a low-voltage single-phase H-bridge inverter with an inductive filter, and a step-up transformer interfacing with the grid is presented. A novel design of inverter current control that attenuates the lower order harmonics is presented in this project. An adaptive harmonic compensation technique with its design is proposed for the lower order harmonic compensation. In accumulation, a proportional-resonant-integral (PRI) controller and its design is also proposed. So, in this project some modification is made in the inverter current control for a grid connected single-phase photovoltaic inverter for ensuring high quality of the current to be injected into the grid.