Abstract: A power supply apparatus includes first and second parallel-connected uninterruptible power supplies (UPSs), each including an AC/DC converter circuit and a DC/AC converter circuit having an input coupled to an output of the AC/DC converter circuit by a DC link, inputs of the AC/DC converter circuits of the first and second UPSs connected in common to an AC source and outputs of the DC/AC converter circuits of the first and second UPSs connected in common to a load. The first and second UPSs are configured to support a test mode wherein the first UPS is test loaded by transferring power from the output of the DC/AC converter circuit of the first UPS to the output of the DC/AC converter circuit of the second UPS. The first UPS may be configured to provide power to the load concurrent with test loading by the second UPS.

Abstract: A loss of a power source for a bus is detected. Responsive to detecting the loss of the power source, a voltage is generated on the bus using an uninterruptible power supply (UPS). A generator is transitioned to a desired output state concurrent with generating the voltage on the bus using the UPS. The generator is coupled to the bus responsive to the generator attaining the desired output state. The UPS may be used to provide power to a load connected to the bus while the generator is in transition. For example, detecting the loss of the power source may be preceded by operating a converter of the UPS coupled to the bus as a rectifier and generating the voltage on the bus using the UPS may include operating the converter of the UPS as an inverter.

Abstract: A power generation system includes a generator configured to be connected to a bus. The system also includes a timing reference signal generator circuit configured to detect a timing variation of a voltage on the bus and to generate a timing reference signal from a timing reference other than the voltage on the bus in response to detection of the variation. The system further includes a generator control circuit configured to synchronize operation of the generator to the timing reference signal.

Abstract: A power system includes a load bus configured to be connected to a power source, a generator and an uninterruptible power supply (UPS). The generator is operated as an induction generator to provide power to the load bus while providing reactive power to the load bus from the UPS. In some embodiments, prior to operating the generator as an induction generator, the generator is operated as an induction motor while the load bus is receiving power from the power source. Responsive to loss of the power source, the UPS may be used to maintain operation of the generator as an induction motor while the prime mover accelerates up to a speed sufficient to drive the generator as an induction generator.

Abstract: A power supply system includes an AC input configured to be coupled to an AC source, an AC output configured to be coupled to a load, a UPS having an input coupled to the AC input and an output coupled to the AC output and a bypass circuit coupled between the AC input and the AC output and configured to open and close a bypass path therebetween. The system further includes a controller configured to control the UPS and the bypass circuit such that the UPS operates as an online UPS for a first input voltage magnitude condition at the AC input and as a standby UPS for a second input voltage magnitude condition at the AC input. A multi-mode converter may be coupled to a DC link of the UPS and configured to be selectively coupled to a battery and the AC input to respectively support battery conversion and current control at the AC input in respective first and second modes of operation of the UPS.

Abstract: A power system includes a load bus configured to be connected to a power source, a generator and an uninterruptible power supply (UPS). The generator is operated as an induction generator to provide power to the load bus while providing reactive power to the load bus from the UPS. In some embodiments, prior to operating the generator as an induction generator, the generator is operated as an induction motor while the load bus is receiving power from the power source. Responsive to loss of the power source, the UPS may be used to maintain operation of the generator as an induction motor while the prime mover accelerates up to a speed sufficient to drive the generator as an induction generator.

Abstract: A loss of a power source for a bus is detected. Responsive to detecting the loss of the power source, a voltage is generated on the bus using an uninterruptible power supply (UPS). A generator is transitioned to a desired output state concurrent with generating the voltage on the bus using the UPS. The generator is coupled to the bus responsive to the generator attaining the desired output state. The UPS may be used to provide power to a load connected to the bus while the generator is in transition. For example, detecting the loss of the power source may be preceded by operating a converter of the UPS coupled to the bus as a rectifier and generating the voltage on the bus using the UPS may include operating the converter of the UPS as an inverter.

Abstract: A power generation system includes a generator configured to be connected to a bus. The system also includes a timing reference signal generator circuit configured to detect a timing variation of a voltage on the bus and to generate a timing reference signal from a timing reference other than the voltage on the bus in response to detection of the variation. The system further includes a generator control circuit configured to synchronize operation of the generator to the timing reference signal.

Abstract: A power supply apparatus includes first and second parallel-connected uninterruptible power supplies (UPSs), each including an AC/DC converter circuit and a DC/AC converter circuit having an input coupled to an output of the AC/DC converter circuit by a DC link, inputs of the AC/DC converter circuits of the first and second UPSs connected in common to an AC source and outputs of the DC/AC converter circuits of the first and second UPSs connected in common to a load. The first and second UPSs are configured to support a test mode wherein the first UPS is test loaded by transferring power from the output of the DC/AC converter circuit of the first UPS to the output of the DC/AC converter circuit of the second UPS. The first UPS may be configured to provide power to the load concurrent with test loading by the second UPS.

Abstract: An uninterruptible power supply apparatus includes a first bidirectional power converter circuit having first and second ports and a second bidirectional power converter circuit having first and second ports. The apparatus further includes a DC link that couples the second port of the first bidirectional power converter circuit to the first port of the second bidirectional power converter circuit. A first load port is coupled to the second port of the second bidirectional power converter circuit and a second load port is coupled to the first port of the first bidirectional power converter circuit. The apparatus further includes a control circuit that is configured to control the first and second bidirectional power converter circuits such that each of the first and second bidirectional power converter circuits can generate and/or condition AC power at each of the first and second load ports.

Abstract: An uninterruptible power supply (UPS) includes a transformer, a low voltage converter (02), a rectifier, and a high voltage inverter (01). The low voltage converter comprises a battery, a first switching device (Q3), a second switching device (Q4), and first drive circuits (41, 42). The high voltage inverter (01) includes first and second load terminals adapted to be coupled across a load in an emergency situation; an output capacitor (C); a third switching device (Q1) and a fourth switching device (Q2), and second drive circuitry (43, 44) for driving the third and fourth switching devices from conducting to non-conducting states and vice versa so as to produce a quasi-sinusoidal output voltage waveform across the load terminals.