Active Power Control of Single Phase Standalone Inverter Systems

Abstract

Continuous and reliable power supply to different connected loads is a challenging and most desirable aspect now a days. Stand-alone mode of operation of inverter system is one of the best ways for getting continuous supply of power.This type of power supply is applicable where distribution of electricity system is not fitted. Forgetting uninterruptable and reliable power supply, proper design of power inverter and a thoroughgoing feedback controller should be needed such that unconcerned about which type of load connected to the inverter, power inverter should be able to produce and maintain a stable and symmetrical sinusoidal output voltage waveform which is the main requirement for the grid connected or standalone power systems. The thesis discusses about the modelling of single phase full bridge inverter using MOSFET as switches.

The thesis then discusses about the sinusoidal pulse width modulation technique used to generate the pulses for the switches used in the single phase inverter connected standalone system. For different load changes, to maintain the proper power flow from input to output,Current Mode Control technique is modelled.Basically, in Current Mode Control we have two feedback loops voltage feedback loop (outer loop) and current feedback loop (inner loop). The output voltage and filter current are considered as feedback loopparameters.The actual output voltage and filter current are compared with the reference voltage and reference current and the error between actual and reference values are given to PI controller.The thesis discusses the modelling of PI controller by Current Mode Control technique and the output of the controller is used as the reference signal in sinusoidal PWM technique for pulses generation in load connected standalone inverter. The simulation results are acquired from MATLAB/ Simulink for controlling the active power of inverter connected standalone system.