Evaluation of modulation strategies for PV fed DCMLIs and its application to dynamic load

The comparison of control strategies of two different topologies of five level diode clamped multilevel inverter (DCMLI), fed by a photovoltaic (PV) module is presented in this paper. The inverters are supplying various dynamic loads. Different types of single phase induction motors have been used as dynamic loads. The control strategies implemented are Phase disposition (PD), Phase opposition disposition (POD), Alternate phase opposition disposition (APOD) and unsymmetrical sine pulse width modulation for the classical five level diode clamped inverter. This topology is compared to another inverter topology that is free from the problem of voltage collapse and needs lesser number of capacitors and clamping diodes. The simulations have been performed using Simulink package of Matrix Laboratory (MALAB) software. The output voltage and output current Total Harmonic Distortion (THD) is analyzed for each of the control strategies. Relative comparison is undertaken for both topologies. The single phase induction motors are loaded by a variable load.