Abstract: A device includes a three phase supply input including a first phase input, a second phase input, and a third phase input. The device further includes a three phase supply output including a first phase output, a second phase output, and a third phase output. The device further includes a three-phase wye-connected auto-transformer having windings including a first winding, a second winding, and a third winding. At least one of the windings is rated for at least a maximum line to line voltage of the three phase supply input. The other two windings are rated for at least a maximum line to neutral voltage of the three phase supply input. One or more of the windings of the three-phase wye-connected auto-transformer are configured to be tapped to generate a voltage sag output as the three phase supply output.

Abstract: A device includes a first silicon-controlled rectifier (SCR), a second SCR connected in anti-parallel with the first SCR, and a commutation module. The commutation module is configured to apply a reverse bias voltage to the first SCR or the second SCR to turn off the first SCR or the second SCR. The device further includes a voltage clamp configured to dissipate energy when the first SCR or the second SCR are turned off. The voltage clamp is charged as one of the first SCR or the second SCR are powered on.

Abstract: An illustrative device includes a first silicon-controlled rectifier (SCR) and a second silicon-controlled rectifier (SCR) connected in anti-parallel and a first commutation module, which includes a first voltage source, a first diode, and a first self-commutating semiconductor switch. The device also includes a second commutation module including a second voltage source, a second diode, and a second self-commutating semiconductor switch. The first voltage source, the first diode, and the first self-commutating semiconductor switch of the first commutation module are connected in series. The second voltage source, the second diode, and the second self-commutating semiconductor switch of the second commutation module are connected in series. The first SCR, the second SCR, the first commutation module, and the second commutation module are connected in parallel. The commutation modules are configured to apply reverse bias voltages to the first and second SCRs to turn off the SCRs.

Abstract: A device includes a three phase supply input including a first phase input, a second phase input, and a third phase input. The device further includes a three phase supply output including a first phase output, a second phase output, and a third phase output. The device further includes a three-phase wye-connected auto-transformer having windings including a first winding, a second winding, and a third winding. At least one of the windings is rated for at least a maximum line to line voltage of the three phase supply input. The other two windings are rated for at least a maximum line to neutral voltage of the three phase supply input. One or more of the windings of the three-phase wye-connected auto-transformer are configured to be tapped to generate a voltage sag output as the three phase supply output.

Abstract: A device includes a first silicon-controlled rectifier (SCR), a second SCR connected in anti-parallel with the first SCR, and a commutation module. The commutation module is configured to apply a reverse bias voltage to the first SCR or the second SCR to turn off the first SCR or the second SCR. The device further includes a voltage clamp configured to dissipate energy when the first SCR or the second SCR are turned off. The voltage clamp is charged as one of the first SCR or the second SCR are powered on.

Abstract: An AC power converter converts power from an AC power source to an AC load. A DC power holding source is coupled to an input half-bridge switch, a common half-bridge switch and an output half-bridge switch. A controller is coupled to at least two of the input half-bridge switch, the common half-bridge switch, and an output half-bridge switch. The controller switches the input half bridge at the first switching frequency in boost mode and at the line frequency in buck mode. The controller also switches the output half bridge switch at the first switching frequency in buck mode and at the line frequency in boost mode. Input and output low pass filters can eliminate switching frequency energy from entering the AC source and load. The converter maintains a DC power holding source voltage slightly above peak AC input voltage and significantly less than twice the peak AC input voltage.

Abstract: An AC power converter converts power from an AC power source to an AC load. A DC power holding source is coupled to an input half-bridge switch, a common half-bridge switch and an output half-bridge switch. A controller is coupled to the input half-bridge switch, the common half-bridge switch, and an output half-bridge switch to generate at least two control signals at a common switching frequency, wherein the controller generates the at least two control signals with a phase difference there between chosen to cause a ripple frequency in both the input low pass filter and the output low pass filter to be double the common switching frequency. An input low pass filter can eliminate switching frequency energy from entering the AC power source. An output low pass filter can eliminate switching frequency energy from entering the AC load.

Abstract: An illustrative device includes a first silicon-controlled rectifier (SCR) and a second silicon-controlled rectifier (SCR) connected in anti-parallel and a first commutation module, which includes a first voltage source, a first diode, and a first self-commutating semiconductor switch. The device also includes a second commutation module including a second voltage source, a second diode, and a second self-commutating semiconductor switch. The first voltage source, the first diode, and the first self-commutating semiconductor switch of the first commutation module are connected in series. The second voltage source, the second diode, and the second self-commutating semiconductor switch of the second commutation module are connected in series. The first SCR, the second SCR, the first commutation module, and the second commutation module are connected in parallel. The commutation modules are configured to apply reverse bias voltages to the first and second SCRs to turn off the SCRs.

Abstract: A voltage sag correction device includes an input terminal adapted to receive a first operating signal having a line-to-neutral voltage. The first operating signal is provided to a load through an output terminal. A regulator module includes a rectifying device adapted to rectify a line-to-line input signal, a storage unit adapted to store energy corresponding to the rectified line-to-line input signal, and an inverter switching device adapted to use the stored energy to generate a correction signal during at least a portion of a voltage sag. An injection transformer in electrical communication with the regulator module is adapted to reduce a voltage of the correction signal. A bypass switch is in a closed position during a normal operating condition such that the injection transformer is bypassed. The bypass switch is in an open position during at least a portion of the voltage sag such that the injection transformer is energized.

Abstract: A voltage sag correction device includes an input terminal adapted to receive a first operating signal having a line-to-neutral voltage. The first operating signal is provided to a load through an output terminal. A regulator module includes a rectifying device adapted to rectify a line-to-line input signal, a storage unit adapted to store energy corresponding to the rectified line-to-line input signal, and an inverter switching device adapted to use the stored energy to generate a correction signal during at least a portion of a voltage sag. An injection transformer in electrical communication with the regulator module is adapted to reduce a voltage of the correction signal. A bypass switch is in a closed position during a normal operating condition such that the injection transformer is bypassed. The bypass switch is in an open position during at least a portion of the voltage sag such that the injection transformer is energized.

Abstract: In dynamic voltage sag correctors and other power conversion equipment having a DC bus that is subject to over-voltage conditions due to power being fed back by a regenerative load, a bus discharge switching device and a discharge resistor are connected in series across the DC bus lines. The discharge switching devices are switched on to discharge the energy storage device connected to the bus, or to separately discharge the two capacitors of a split capacitor DC bus, to eliminate the over-voltage conditions. The discharge switching devices may be switched on and off periodically with a selected duty cycle to discharge energy from the energy storage capacitor or other energy storage device through the discharge resistor at a rate which does not exceed the power rating of the discharge resistor. The discharge switching device may be switched with a fixed duty cycle or with a variable duty cycle that is based on the dynamic power dissipation characteristics of the discharge resistor.