Abstract: A UPS is operated by deasserting a static switch drive signal, e.g., a gate signal to a thyristor, and then delaying provision of power from a converter circuit of the UPS, e.g., an inverter or other source of AC power, until after the switch has current commutated to an off state. For example, expiration of a predetermined time interval following deassertion of the switch drive signal may be detected, and the converter circuit may be enabled to drive the output of the UPS responsive to the detected expiration of the predetermined time interval. Alternatively, a current in the static switch may be detected, and the converter circuit may be enabled to drive the output of the UPS responsive to the detected current. The invention may be embodied as methods and apparatus.

Abstract: A UPS is operated by deasserting a static switch drive signal, e.g., a gate signal to a thyristor, and then delaying provision of power from a converter circuit of the UPS, e.g., an inverter or other source of AC power, until after the switch has current commutated to an off state. For example, expiration of a predetermined time interval following deassertion of the switch drive signal may be detected, and the converter circuit may be enabled to drive the output of the UPS responsive to the detected expiration of the predetermined time interval. Alternatively, a current in the static switch may be detected, and the converter circuit may be enabled to drive the output of the UPS responsive to the detected current. The invention may be embodied as methods and apparatus.

Abstract: A closed loop power converter circuit of a UPS or other power supply includes a pulse width modulator circuit in a forward path of the closed loop power circuit. A compensation circuit provides pulse width commands to the pulse width modulator at a first rate. A feedback circuit digitally filters samples of an output of the closed loop power converter at a second rate greater the first rate and that provides the filtered samples to the compensation circuit. In some embodiments, the compensation circuit may be operative to compensate for the phase lag associated with a low pass output filter.

Abstract: A UPS is operated by deasserting a static switch drive signal, e.g., a gate signal to a thyristor, and then delaying provision of power from a converter circuit of the UPS, e.g., an inverter or other source of AC power, until after the switch has current commutated to an off state. For example, expiration of a predetermined time interval following deassertion of the switch drive signal may be detected, and the converter circuit may be enabled to drive the output of the UPS responsive to the detected expiration of the predetermined time interval. Alternatively, a current in the static switch may be detected, and the converter circuit may be enabled to drive the output of the UPS responsive to the detected current. The invention may be embodied as methods and apparatus.

Abstract: A closed loop power converter circuit of a UPS or other power supply includes a pulse width modulator circuit in a forward path of the closed loop power circuit. A compensation circuit provides pulse width commands to the pulse width modulator at a first rate. A feedback circuit digitally filters samples of an output of the closed loop power converter at a second rate greater the first rate and that provides the filtered samples to the compensation circuit. In some embodiments, the compensation circuit may be operative to compensate for the phase lag associated with a low pass output filter. For example, the compensation circuit may include a high pass IIR filter, operating at the first rate, that compensates for a pole associated with the low pass output filter, while the feedback circuit includes a low pass filter, operating at the second rate, that compensates for a frequency response peak associated with the high pass filter.