Multi switch inverter, personal power plant system using thereof and method to generate AC power sine wave

A personal power plant system comprising:

• an input selector configured to select a power source;
• a battery bank comprising a plurality of battery cassettes coupled in series, wherein each battery cassette comprises a plurality of batteries connected in series;
• a charger configured to charge the battery bank using electrical energy from the selected power source;
• a battery selector comprising a plurality of switches configured to select one or more of the plurality of battery cassettes to charge;
• a plurality of solar panels electrically coupled to respective battery cassettes of the battery bank, wherein ones of the plurality of solar panels are selectively coupled to the input selector;
• an inverter, wherein said inverter comprises:
• a plurality of DC input terminals wherein each DC input terminal is electrically coupled to respective battery cassettes of the battery bank;
• a bridge circuit configured to switch a polarity of a voltage applied to a load electrically coupled thereto;
• a plurality of semiconductor switches comprising MOS-FETS electrically coupled to respective DC input terminals, wherein the plurality of semiconductor switches are electrically coupled to the bridge circuit;
• and
• a plurality of Schottky diode to prevent back backward current flow, wherein an anode of each Schottky diode is electrically coupled to a corresponding semiconductor switch of the plurality of semiconductor switches and a cathode of each Schottky diode is electrically coupled to the bridge circuit;
• and
• a controller configured to generate a predetermined switching sequence to be applied to the plurality of semiconductor switches, wherein the controller is configured to sequentially connect and disconnect the MOS-FETS of the plurality of semiconductor switches to apply a multi-level stepped voltage waveform with a modulation of a selected step thereof across the bridge circuit such that an output from the bridge circuit approximates an AC power sine wave with reduced harmonic distortion.

A method for converting DC voltage to AC voltage comprising:

• with an inverter including a plurality of DC input terminals, a plurality of semiconductor switches electrically coupled to respective DC input terminals, and a bridge circuit configured to switch a polarity of a voltage applied to a load coupled thereto,
• connecting a plurality of battery cassettes in series to form a battery bank, wherein a center tap is provided between the adjacent battery cassettes;
• connecting the center taps and a positive electrode of the battery bank to respective DC input terminals;
• operating the plurality of semiconductor switches according to predetermined switching sequences such that a multi-level stepped voltage waveform with a modulated width of selected step thereof is generated;
• applying the multi-level stepped voltage waveform to the bridge circuit;
• and
• switching the polarity of the voltage applied to the load coupled to the bridge circuit to generate an AC power sine wave with reduced harmonic distortion.