Maximum Power Point Tracking (MPPT) for a PV Powered Z-Source Inverter

摘要

Objectives: A constant voltage maximum power point tracking algorithm based PV powered z-source inverter was examined for varying irradiation and temperature to maximize power output. Method: Maximum power point tracking algorithm applied to photo voltaic system keep the boost converter output constant. The constant output from boost converter is taken to three phase z-source inverter with load arrangements. Three phase z-source inverter is operated in closed loop control for voltage and frequency synchronization. Eventually three phase z-source inverter output with LC filters will produce sinusoidal output fed to the three phase asynchronous machine. Findings: Simulations are provided to validate the presentation of the proposed algorithm. Perturb and Observation Algorithm (P&O) used for maximum power point tracking may accomplish fast maximum power point for rapid change of environmental conditions such as irradiance and temperature. The usual means to work with lesser MPP voltages is to have a supplementary DC-DC boost converter with conventional inverters like current source inverter or voltage source inverter (CSI or VSI). However, proposed z-source inverter can either buck or boost AC output voltage without any supplementary DC-DC boost converter which is not possible in the conventional CSI or VSI. Moreover, the z-network of three phase z-source inverter comprising of pair of capacitors and inductors forms a second order filter and filters unwanted voltage sags of the DC voltage source thereby improving the quality of power and total harmonic distortion. Consequently enhanced power quality without sag and lesser total harmonic distortion is given to three phase asynchronous machine. Thus a MPPT based PV powered z-source inverter is effective in comparison with conventional inverters. Applications: Proposed system finds its applications in renewable energy sources like solar, wind and combined solar- wind systems, electric vehicles and AC motor drives.