Abstract:
Currently, the control of grid connected inverters is an appealing area of research. There exists
several control schemes, but this thesis primarily focuses classical control (P/PI) of grid tied
inverters under diverse variations such as LCL filter parameter values and grid impedance. The
performance of conventional classical PID controller renders down resulting in a large steady
state error; high THD level in the output current and in its worse scenario destabilizes the
designed system if controller gains are not seleted properly. To achieve efficient results proper
tuning of gain parameters is necessary for small steady state error with very low level of THD in
the output current. This thesis investigates the limitations of a conventional PID controller
considering stability and system response by changing the controller gains in conjunction with
LCL filter parameters. The controller gain is varied within permissible range of bandwidth of the
system while maintaining the steady state response, frequency response and overall efficiency
under strong grid harmonics. The MATLAB/Simulink results are incorporated for the proper
analysis of controller behavior with stability range under the influence of grid impedance
variations.
