Photovoltaic inverter

A photovoltaic inverter comprising:

• an input unit comprising a first input unit and a second input unit respectively connected to a positive (+) polarity and a negative (−) polarity of a photovoltaic module;
• a booster unit configured to boost a voltage of the photovoltaic module delivered from the input unit through a switching device;
• a capacitor configured to charge the voltage boosted by the booster unit;
• and
• an inverter unit comprising a positive (+) polarity connection terminal and a negative (−) polarity connection terminal and configured to convert the voltage charged in the capacitor into an alternating current (AC) and provide the converted AC voltage for an electric power system;
• and
• the switching device configured to automatically connect the positive (+) polarity or negative (−) polarity of the photovoltaic module to the first terminal and the second terminal according to polarities of the inverter unit,
• wherein the switching device comprises:
• a first input terminal connected to the first input unit at one end thereof;
• a second input terminal connected to the second input unit at one end thereof;
• a first comparator configured to compare the first input terminal with a preset reference voltage and output a first comparison result including a high signal or a low signal;
• a second comparator configured to compare the second input terminal with the preset reference voltage and output a second comparison result, opposite to the first comparison result, including a low signal or a high signal;
• a first switching unit connected to the first comparator and the first input terminal at one end thereof and configured to be switched based on an output from the first comparator;
• a second switching unit connected to the second comparator and the second input terminal at one end thereof and configured to be switched based on an output from the second comparator;
• a first output terminal configured to connect the first input terminal to the positive (+) polarity connection terminal of the inverter unit when the output from the first comparator is a high signal, and configured to connect the second input terminal to the positive (+) polarity connection terminal of the inverter unit when the output from the second comparator is a high signal;
• and
• a second output terminal configured to connect the first input terminal to the negative (−) polarity connection terminal of the inverter unit when the output from the first comparator is a low signal, and configured to connect the second input terminal to the negative (−) polarity connection terminal of the inverter unit when the output from the second comparator is a low signal.