The present invention provides a system comprising PoE apparatus including midspans, switches and routers that can provide high powered PoE connections that enable the recovery of DC power in sufficient quantities that allow it to be converted to AC power by way of an inverter. The invention also provides a method for providing AC power, data and light to office workstations using a single PoE connection. The invention further comprises a common mode signalling system that operates independently of any TCP/IP signal transmitted through an Ethernet connection wherein said signalling system is adapted to communicate with and control PoE powered devices.

The present invention provides a system comprising PoE apparatus including midspans, switches and routers that can provide high powered PoE connections that enable the recovery of DC power in sufficient quantities that allow it to be converted to AC power by way of an inverter. The invention also provides a method for providing AC power, data and light to office workstations using a single PoE connection. The invention further comprises a common mode signalling system that operates independently of any TCP/IP signal transmitted through an Ethernet connection wherein said signalling system is adapted to communicate with and control PoE powered devices.

A snubber device to be mounted to a terminal of a semiconductor module is provided. The snubber device includes n (n: integer of 1 or greater) parallel charge paths each having a positive-side capacitor, a first diode, and a negative-side capacitor sequentially connected in series between positive-side and negative-side terminals of the semiconductor module, and configured to enable current to flow from the positive-side terminal toward the negative-side terminal; and (n+1) parallel discharge paths each of which having a second diode connected between the negative-side terminal or the negative-side capacitor of an N.sup.th charge path (N: integer within a range of 0Nn) of then charge paths and the positive-side capacitor of a (N+1).sup.th charge path of the n charge paths or the positive-side terminal, and configured to enable current to flow from the negative-side terminal toward the positive-side terminal via at least one of the negative-side and positive-side capacitors.

A snubber device to be mounted to a terminal of a semiconductor module is provided. The snubber device includes n (n: integer of 1 or greater) parallel charge paths each having a positive-side capacitor, a first diode, and a negative-side capacitor sequentially connected in series between positive-side and negative-side terminals of the semiconductor module, and configured to enable current to flow from the positive-side terminal toward the negative-side terminal; and (n+1) parallel discharge paths each of which having a second diode connected between the negative-side terminal or the negative-side capacitor of an N.sup.th charge path (N: integer within a range of 0Nn) of then charge paths and the positive-side capacitor of a (N+1).sup.th charge path of the n charge paths or the positive-side terminal, and configured to enable current to flow from the negative-side terminal toward the positive-side terminal via at least one of the negative-side and positive-side capacitors.

A method and apparatus for secondary side current mode control of a converter are provided. In the method and apparatus, an output voltage of the converter is detected, where the converter has primary and secondary windings that are galvanically isolated in respective primary and secondary sides. A secondary control signal is generated in the secondary side based at least in part on the output voltage and a reference voltage. The secondary control signal is converted to a primary control signal provided in the primary side. The converter is driven in the primary side based at least in part on the primary control signal and a current sense signal indicative of a current flowing through the primary winding.

A vehicle includes an engine and alternator having a field coil and a plurality of output windings, a field current controller configured to receive an AC input and convert the AC input into a regulated DC output that is supplied to the field coil of the alternator, and a controller configured to monitor at least one operating parameter of the field current controller and to compare a monitored value of the at least one operating parameter to a threshold range.

A power supply, including a primary pre-converter, coupled to supplying mains, configured to receive an AC voltage at low frequency and output a high DC voltage, and further configured to receive the high DC voltage and to output the alternating current; a primary converter, disposed on a primary side of the power supply, coupled to the high DC voltage from the primary pre-converter; an isolating transformer to receive the high frequency AC voltage and output a high frequency secondary AC voltage, and to receive a high frequency secondary AC current and to output primary high frequency AC current; and an output converter, on a secondary side of the power supply, wherein the output converter is configured to receive high frequency AC voltage from the isolating transformer and to output a DC voltage of a first or second polarity to an output, and wherein the output converter is configured to receive DC current of a first or second direction from the output and to output a high frequency AC current to the isolating transformer.

According to one aspect, a UPS system is provided including an input configured to receive AC input power, an output configured to provide AC output power to a load, a rectifier coupled to the input, an inverter coupled to the rectifier and the output, an auxiliary branch coupled to the input and the output, and a controller coupled to the rectifier, the inverter, and the auxiliary branch, and configured to receive voltage information indicative of a voltage level of the AC input power and AC output power, select, based on the voltage information satisfying a first condition, a buck mode of operation, select, based on the voltage information satisfying a second condition, a freewheel mode of operation, and communicate one or more control signals to at least one of the rectifier, the inverter, and the auxiliary branch based on the selected mode of operation.

The present invention provides a system comprising PoE apparatus including midspans, switches and routers that can provide high powered PoE connections that enable the recovery of DC power in sufficient quantities that allow it to be converted to AC power by way of an inverter. The invention also provides a method for providing AC power, data and light to office workstations using a single PoE connection. The invention further comprises a common mode signaling system that operates independently of any TCP/IP signal transmitted through an Ethernet connection wherein said signaling system is adapted to communicate with and control PoE powered devices.

The present invention provides a system comprising PoE apparatus including midspans, switches and routers that can provide high powered PoE connections that enable the recovery of DC power in sufficient quantities that allow it to be converted to AC power by way of an inverter. The invention also provides a method for providing AC power, data and light to office workstations using a single PoE connection. The invention further comprises a common mode signaling system that operates independently of any TCP/IP signal transmitted through an Ethernet connection wherein said signaling system is adapted to communicate with and control PoE powered devices.