Abstract:
In grid connected parallel solar inverter configuration, the power sharing between the inverter modules are
achieved by sharing the current at identical AC output operating
voltage across each inverter module. In conventional parallel
configuration, high DC potentials are required to synthesize the
identical AC output voltage across the inverter modules. Due
to high DC voltages, the DC capacitor and switching devices
would experience high dv/dt during inverter operation that
would affect the performance of the solar power conditioning
system (PCS). In this work, a method of reducing DC potentials
across the individual inverter module is evaluated using dual
two level inverter configuration. In the dual two level inverter
configuration, the DC bus voltage would be shared between the
inverter modules to synthesize the full AC voltage across the grid
terminals. For appropriate sharing of the DC potential between
the inverter modules based on the maximum available power
point of the solar farm, a coordinated closed loop control is
implemented based on the small signal analysis aiming to track
not only the maximum power point but also grid voltage. The
proposed configuration along with the closed loop control is
evaluated analytically and results are validated by simulating
circuit in MATLAB simulink.
