Reactive power requirements for cascaded H-Bridge photovoltaic systems

Cascaded H-Bridge (CHB) multilevel converters provide a number of attractive features for photovoltaic (PV) power systems. They have high quality output waveforms, high efficiency and the ability to incorporate multiple Maximum Power Point Tracking (MPPT) schemes. This paper investigates the ability of the CHB PV system to export maximum power for different configurations of PV arrays among the H-Bridges. It is shown that there is a minimum number of H-Bridges required to have PV arrays to ensure the maximum power is extracted without reactive power compensation. Reactive power must be injected or absorbed to extract maximum power when the minimum number is not reached. Simulation and experimental results are presented to validate the investigation.