| 主权项 |
1. A DC to AC inverter arrangement for converting Direct Current power from photovoltaic panels to AC power of a desired AC output voltage or current at output terminals and having a sinusoidal waveform of a desired frequency comprising:-
A number of substantially identical microinverters combined in the same mechanical housing, each microinverter being configured to be powered from a respective photovoltaic sub-array via a positive and a negative DC input terminal, and configured so that the positive and negative input terminals from each sub-array get connected through a common mode filter comprising a common-mode choke to the positive and negative terminals of an associated smoothing capacitor, the positive and negative terminals of the smoothing capacitor also being connected to the positive and negative inputs of an associated H-bridge of switching transistors, and each H-bridge having a first output connected to a first output terminal of the associated microinverter and a second output connected through a low-pass filter to a second output terminal of the associated microinverter; a common switching controller for controlling the switching of each H-bridge in each of said microinverters to connect said first output terminals of each H-bridge via an appropriate switching transistor of the H-bridge alternately at said desired AC output frequency to the positive and the negative H-bridge inputs from the respective terminals of said associated smoothing capacitor while controlling the second output of each H-bridge to be connected via another appropriate switching transistor of the H-bridge alternately to the same or opposite polarity H-bridge input at a high switching frequency with a duty factor chosen so as to provide an effective mean value equal to a point on said sinusoidal waveform, and wherein the outputs of said microinverters are combined at the inverter output to provide said desired voltage or current having said sinusoidal waveform at the combined output at said output terminals. |
