Hybrid DC-to-AC conversion system and method of operating the same

A method of operating a hybrid DC-to-AC conversion system;

• steps of the method comprising:
• (a) providing a first DC input voltage and a second DC input voltage, wherein the second DC input voltage is greater than the first DC input voltage;
• (b) providing a power conversion apparatus, wherein the power conversion apparatus has a first power switch, a second power switch, a third power switch and a fourth power switch;
• the first power switch, the second power switch and the third power switch are connected in series to form a first path, and the first path is connected in parallel to the first DC input voltage;
• the fourth power switch, the second power switch and the third power switch are connected in series to form a second path, and the second path is connected in parallel to the second DC input voltage and is configured to convert the first DC input voltage or the second DC input voltage into an AC output voltage to supply a load;
• (c) providing a comparison unit, wherein the comparison unit is configured to receive the AC output voltage and an external reference voltage;
• (d) outputting a control signal by the comparison unit to control the power conversion apparatus converting the first DC input voltage into the AC output voltage when an absolute value of the AC output voltage is less than or equal to the external reference voltage;
• and
• (e) outputting the control signal by the comparison unit to control the power conversion apparatus converting the second DC input voltage into the AC output voltage when the absolute value of the AC output voltage is greater than the external reference voltage.