Abstract: The configurations of a three-phase buck-boost power factor correction (PFC) circuit and a controlling method thereof are provided in the present invention. The proposed circuit includes a first single-phase buck-boost PFC circuit receiving a first phase voltage and having a first and a second output terminals and a neutral-point for outputting a first and a second output voltages, a second single-phase buck-boost PFC circuit receiving a second phase voltage and coupled to the first and the second output terminals and the neutral-point, a third single-phase buck-boost PFC circuit receiving a third phase voltage and coupled to the first and the second output terminals and the neutral-point, a first and a second output capacitors coupled to the first and the second output terminals respectively, and to the neutral-point also and a neutral line coupled to the neutral-point.

Abstract: Provided is an uninterruptible power supply for providing a sinusoidal-wave output AC voltage. The uninterruptible power supply is advantageous in terms of a DC/DC converter unit consisted of a plurality of DC/DC converter, in which the input terminals of the DC/DC converters are connected in parallel with each other and the output terminals of the DC/DC converters are connected in series with each other. The output DC voltages of the DC/DC converters are configured to sum up to form a full-wave rectified DC voltage, which can be converted into a sinusoidal-wave output AC voltage by an inverter. Furthermore, the uninterruptible power supply provides an energy recycle converter configured for recycling the redundant energy of the uninterruptible power supply to charge a battery pack.

Abstract: An integrated converter is provided. The integrated converter includes an AC/DC converter electrically connected to a three-phase power supply for converting an alternating current into a first direct current and achieving the object of the power factor correction; and a DC/DC converter electrically connected to the AC/DC converter for converting the first direct current into a second direct current, wherein while the AC power supply is electricity-drop, the controlling switch is turned on by the integrated converter and the integrated converter is switched from an AC/DC working mode to a DC/DC working mode, and while the AC power supply is restored to normal, the controlling switch is turned off by the integrated converter and the integrated converter is switched from said DC/DC working mode to the AC/DC working mode.

Abstract: A parallel inverter system includes a plurality of inverters of an instantaneous voltage control type, an output bus, an active power bus, a phase bus, and controlling devices. The output bus is used for connecting outputs of said plurality of inverters to a load. The active power bus is connected to the plurality of inverters so as to provide an active power sharing reference. The phase bus is connected to the plurality of inverters so as to provide a system phase reference. And, controlling devices control sinusoidal wave references of inverters to have the same phase, the reactive power, and the active power responsive to the active power sharing reference and the system phase reference. The related methods are also discussed.

Abstract: An integrated converter is provided. The integrated converter includes an AC/DC converter electrically connected to a three-phase power supply for converting an alternating current into a first direct current and achieving the object of the power factor correction; and a DC/DC converter electrically connected to the AC/DC converter for converting the first direct current into a second direct current, wherein while the AC power supply is electricity-drop, the controlling switch is turned on by the integrated converter and the integrated converter is switched from an AC/DC working mode to a DC/DC working mode, and while the AC power supply is restored to normal, the controlling switch is turned off by the integrated converter and the integrated converter is switched from said DC/DC working mode to the AC/DC working mode.

Abstract: A parallel inverter system includes a plurality of inverters of an instantaneous voltage control type, an output bus, an active power bus, a phase bus, and controlling devices. The output bus is used for connecting outputs of said plurality of inverters to a load. The active power bus is connected to the plurality of inverters so as to provide an active power sharing reference. The phase bus is connected to the plurality of inverters so as to provide a system phase reference. And, controlling devices control sinusoidal wave references of inverters to have the same phase, the reactive power, and the active power responsive to the active power sharing reference and the system phase reference. The related methods are also discussed.