A system and method for supplying uninterruptible power has active power negotiation and an extended range. The system includes a housing, a power supply input, a power source equipment input, a powered device output, an alternative power supply, and a control module. The control module includes a comparator, a switch, a converter, and an injector. The injector includes a regulator and power autonegotiation module. The injector actively manages the power to the powered device, even when the PoE available from older power source equipment differs from the PoE requirements of an updated powered device. There can also be an Ethernet switch as a power source equipment extension between the powered device and the system. The Ethernet switch extends the range of the powered device from the system.

Systems and methods are described for providing power. A system comprising a generator, an inverter, and a battery can be used to provide power. The system can also comprise a transfer switch. The system can provide power to another device.

An uninterruptible power supplying method and an uninterruptible power supply. The method includes switching an uninterruptible power supply to a bypass working mode from a main loop working mode, so as to provide mains power for a load through a bypass; determining the working mode of the uninterruptible power supply; and when the uninterruptible power supply is in the bypass working mode, adjusting a working frequency of at least one switch tube in a main loop of the uninterruptible power supply to a second frequency from a first frequency, where the second frequency is less than the first frequency, so as to reduce power loss when the uninterruptible power supply is in the bypass working mode.

In order to add an emergency light function to a fluorescent LED lighting device, thereby increasing safety during a power outage, this LED lighting device, which can be mounted between a pair of sockets for fluorescent lighting, is equipped with a first power supply circuit, which lights the LED using direct current power obtained by converting/rectifying alternating current power supplied from the sockets, and a second power supply circuit, which lights the LED using an embedded battery. An embedded SW controller detects that a sudden drop in the current value or the voltage value in the lighting device, from a prescribed value Von when the lighting switch is turned on to a value that is essentially zero, occurs within a prescribed time T. When the sudden drop occurs two or more times in the prescribed time (FIG. 5), it is determined that a normal operation of turning off the light has been performed, and the light is turned off, and when the sudden drop occurs only once during the prescribed time (FIG. 6), it is determined that a power outage has occurred, and the LED is lighted as an emergency light using the second power supply circuit.

A power source protection device and a power source protection method are disclosed herein. The power source protection device includes a power supply, a power source managing unit and a signal sending unit. The power supply provides a DC input voltage. The power source managing unit receives the DC input voltage, and when a determining voltage related to the input voltage is larger than a set voltage, enters a startup state and outputs a supply voltage. After receiving the supply voltage, the power source managing unit transforms the DC input voltage into a standby power output voltage and provides the standby power output voltage when the signal sending unit sends a control signal to the power source managing unit within an enabling time. VVhen it has not received the control signal within the enabling time, the power source managing unit enters a shutdown state.

A power supply control circuit, which is connected to a stabilized direct current power supply having a pair of first and second output terminals and a pair of first and second remote sensing terminals, includes: a current detector configured to detect an output current that is supplied to a load from the stabilized direct current power supply, and to output a current detection voltage; a current difference output unit configured to output a current difference voltage corresponding to a voltage difference between the current detection voltage and a current setting voltage; and a control voltage generator configured to generate a control voltage and output the control voltage to the first remote sensing terminal so as to perform a constant current control operation. The current detector, the current difference output unit and the control voltage generator are operated by only the direct current voltage supplied by the auxiliary power supply.

Various embodiments of a DC plant. In one embodiment, the DC plant includes (1) power sources couplable to a common DC bus, (2) rectifiers and DC-DC converters associated with the power sources and (3) a DC plant controller. The DC plant controller includes a source identifier configured to identify the power sources, a source prioritizer coupled to the source identifier and configured to prioritize the power sources based on at least one criterion, and an output characteristic assigner coupled to the source prioritizer.

A power supply system includes an electric storage device, a connecting terminal area, a main energization line, a sub-energization line, a first energization switching unit for switching between an energized state and a non-energized state of an energization line of the main energization line connecting the electric storage device and a loading apparatus, a second energization switching unit for switching between an energized state and a non-energized state of an energization line of the main energization line connecting a branched part and the connecting terminal area, a third energization switching unit for switching between an energized state and a non-energized state of an energization line of the main energization line connecting the second energization switching unit and the connecting terminal area, and a control device that detects switching states of the first, second and third energization switching units and that controls their switching operations.

A power supply system includes an electric storage device, a connecting terminal area, a main energization line, a sub-energization line, a first energization switching unit for switching between an energized state and a non-energized state of an energization line of the main energization line connecting the electric storage device and a loading apparatus, a second energization switching unit for switching between an energized state and a non-energized state of an energization line of the main energization line connecting a branched part and the connecting terminal area, a third energization switching unit for switching between an energized state and a non-energized state of an energization line of the main energization line connecting the second energization switching unit and the connecting terminal area, and a control device that detects switching states of the first, second and third energization switching units and that controls their switching operations.

Systems and methods of controlling an uninterruptible power supply are provided. The uninterruptible power supply includes an input configured to receive input power, an output, a power conversion circuit coupled with the input and the output, and a controller coupled with the power conversion circuit. The power conversion circuit includes an inverter, which includes a low pass filter. The low pass filter includes an inductor, and the controller is configured to provide control signals to the inverter such that a first current, measured at the inductor, generates a second current, measured at the output, where the first current has a first polarity and the second current having a second polarity, and the first polarity is either zero or the same polarity as the second polarity.