Abstract: An uninterruptible power supply for providing an output power signal to a load comprises a ferroresonant transformer, a resonant capacitor, and an inverter. The resonant capacitor is operatively connected to the ferroresonant transformer. The inverter is operatively connected to the ferroresonant transformer. The inverter is configured to generate the output power signal based on at least one inverter control signal such that the output power signal is a quasi square wave having at least one change of phase and an upper limit. The at least one inverter control signal is held in an OFF state during at least a portion of the at least one change of phase, pulse-width modulated during at least a portion of the at least one change of phase, and held in an ON state when the output power signal is at the upper limit.

Abstract: An uninterruptible power supply for providing an output power signal to a load comprises a ferroresonant transformer, a resonant capacitor, and an inverter. The resonant capacitor is operatively connected to the ferroresonant transformer. The inverter is operatively connected to the ferroresonant transformer. The inverter is configured to generate the output power signal based on at least one inverter control signal such that the output power signal is a quasi square wave having at least one change of phase and an upper limit. The at least one inverter control signal is held in an OFF state during at least a portion of the at least one change of phase, pulse-width modulated during at least a portion of the at least one change of phase, and held in an ON state when the output power signal is at the upper limit.

Abstract: An uninterruptible power supply for providing an output power signal to a load comprises a ferroresonant transformer, a resonant capacitor, and an inverter. The resonant capacitor is operatively connected to the ferroresonant transformer. The inverter is operatively connected to the ferroresonant transformer. The inverter is configured to generate the output power signal based on at least one inverter control signal such that the output power signal is a quasi square wave having at least one change of phase and an upper limit. The at least one inverter control signal is held in an OFF state during at least a portion of the at least one change of phase, pulse-width modulated during at least a portion of the at least one change of phase, and held in an ON state when the output power signal is at the upper limit.

Abstract: An uninterruptible power supply for providing an output power signal to a load comprises a ferroresonant transformer, a resonant capacitor, and an inverter. The resonant capacitor is operatively connected to the ferroresonant transformer. The inverter is operatively connected to the ferroresonant transformer. The inverter is configured to generate the output power signal based on at least one inverter control signal such that the output power signal is a quasi square wave having at least one change of phase and an upper limit. The at least one inverter control signal is held in an OFF state during at least a portion of the at least one change of phase, pulse-width modulated during at least a portion of the at least one change of phase, and held in an ON state when the output power signal is at the upper limit.

Abstract: An uninterruptible power supply for providing an output power signal to a load has a ferroresonant transformer, a resonant capacitor operatively connected to the ferroresonant transformer, and an inverter operatively connected to the ferroresonant transformer. The inverter is configured to generate the output power signal based on at least one inverter control signal such that the output power signal is a quasi square wave having a first change of phase, an upper limit, and a second change of phase. The at least one inverter control signal is pulse-width modulated between the first change of phase and the upper limit, pulse-width modulated between the upper limit and the second change of phase, and held in an ON state when the output power signal is at the upper limit.

Abstract: An uninterruptible power supply for providing an output power signal to a load has a ferroresonant transformer, a resonant capacitor operatively connected to the ferroresonant transformer, and an inverter operatively connected to the ferroresonant transformer. The inverter is configured to generate the output power signal based on at least one inverter control signal such that the output power signal is a quasi square wave having a first change of phase, an upper limit, and a second change of phase. The at least one inverter control signal is pulse-width modulated between the first change of phase and the upper limit, pulse-width modulated between the upper limit and the second change of phase, and held in an ON state when the output power signal is at the upper limit.

Abstract: The present invention may be embodied as an uninterruptible power supply comprising an input section, an output section, an inverter section, and a transformer. The transformer is operatively connected to the input section, the output section, and the inverter section. The uninterruptible power supply operates in a line mode and in a standby mode. In the standby mode, the output section generates an output power signal from a standby signal generated by the inverter section based on the alternative power source and at least one inverter control signal. When the uninterruptible power supply operates in the standby mode, the at least one inverter control signal is pulse-width modulated during at least a first portion of a cycle of the output power signal and not pulse-width modulated during at least a second portion of the cycle of the output power signal.

Abstract: The present invention may be embodied as an uninterruptible power supply comprising an input section, an output section, an inverter section, and a transformer. The transformer is operatively connected to the input section, the output section, and the inverter section. The uninterruptible power supply operates in a line mode and in a standby mode. In the standby mode, the output section generates an output power signal from a standby signal generated by the inverter section based on the alternative power source and at least one inverter control signal. When the uninterruptible power supply operates in the standby mode, the at least one inverter control signal is pulse-width modulated during at least a first portion of a cycle of the output power signal and not pulse-width modulated during at least a second portion of the cycle of the output power signal.