Various methods and systems are provided for a power supply system. In one example, a method and system includes a power distribution unit (PDU) configured to receive power from a main power source and an uninterruptible power supply (UPS). The UPS includes a timer and the UPS is configured to directly power an output alternating current (AC) load after the main power source in unavailable. The UPS is also configured to power an output high voltage direct current (HVDC) load after the main power source is unavailable for a time delay measured by the timer.

Various systems are provided for a power supply system. In one example, the system includes a power distribution unit configured to receive power from a main power source and an uninterruptible power supply (UPS), wherein the UPS is configured to directly power an output AC load, the UPS is further configured to power an output DC load after coupled through one or more transformers.

A method and apparatus is described for conveying the amount of loading of a power source to a load control device by controlling the frequency of the AC power output from that power source in a manner that controlled frequency represents the loading. At a different location in the power system, the frequency is measured and the corresponding loading of the power source is used to prevent or alleviate a power source overload.

An air conditioning device includes an alternating current (AC) bus, a direct current (DC) bus, a first AC/DC circuit, a first DC/AC circuit, and a backup power supply apparatus. The AC bus is connected to two power supplies through a switching circuit. The backup power supply apparatus is connected to the DC bus or the AC bus. The backup power supply apparatus provides electric energy for the DC bus or the AC bus when the two power supplies are switched or fail, so that the first air conditioning load is not powered off. The backup power supply apparatus may supply power to the load when the two power supplies are switched or fail.

An elevator includes an elevator motor, a motor drive for the elevator motor having a frequency converter including a rectifier bridge, an inverter bridge and a DC link in between, which frequency converter is controlled via a controller, the rectifier bridge being connected to AC mains via three feed lines including chokes, and the rectifier bridge being realised via controllable semiconductor switches, an isolation relay being located between the feed lines and AC mains, a backup power supply at least for emergency drive operation, an emergency control for performing an automatic emergency drive, the backup power supply is via a first switch connectable with only a first of the feed lines. A second and/or third of the feed lines is via a second switch connectable as power supply to a car door arrangement, the first switch as well as the second switch are controlled by the emergency control, and the emergency control is connected to a manual drive circuit having a manual drive switch for a manual rescue drive. The elevator includes a first feedback circuit configured to provide to the emergency control first information indicating the switching state of the isolation relay, a second feedback circuit which is configured to provide to the emergency control second information indicating switching state of the first switch. The emergency control is configured to selectively allow or prevent the emergency drive operation on the basis of the first information and the second information.

A request is received for a higher torque from a torque controller than is possible from a power supply. The torque controller is coupled to a motor and the power supply, and the motor is coupled to an actuator. The actuator ultimately establishes resistance for a user in an exercise. An energy storage device is discharged to the motor in order to generate the higher torque, wherein the energy storage device is indirectly coupled to the torque controller.

The present invention provides an online interactive uninterruptible power supply and method for control thereof. The online interactive uninterruptible power supply includes: an automatic voltage regulator and a changeover switch which are sequentially connected between an AC input and an AC output; a rectifying circuit, an input of the rectifying circuit being connected to the AC input; a charger, an input of the charger being connected to an output of the rectifying circuit and an output of the charger being configured for connection to a rechargeable battery; a DC-DC converter, an input of the DC-DC converter being connected to the rechargeable battery; and a first inverter, an input of the first inverter being connected to an output of the DC-DC converter. The changeover switch is configured to controllably connect the AC output to one of the automatic voltage regulator and an output of the first inverter. The online interactive uninterruptible power supply of the present invention can realize battery-free AC startup.

An uninterruptible power system and an operation method thereof are provided. The uninterruptible power system comprises a DC-AC conversion circuit, a plurality of switches, a plurality of sensing units, a plurality of output ports and a control unit. Each output port is electrically coupled to an output terminal of the DC-AC conversion circuit sequentially through one of the sensing units and one of the switches. The control unit is configured to define members of at least one group from the output ports according to a system setting, and define which members of each group are non-critical output ports according to the system setting. The control unit is further configured to set, according to the system setting, at least one condition for all non-critical output ports in each group to simultaneously stop supplying power, and to accordingly control the operations of the corresponding switches.

An electrical generator is provided. The electrical generator can include a generator, an electric motor, and a battery. The generator has a rotatable shaft and stationary component and be operatively coupled via a drive belt to the motor, which provides torque to the rotatable shaft of the generator The battery is operatively coupled to the motor. The generator can be operatively coupled to a utility grid via a transformer/invertor that can import current from the utility grid to charge the battery when the utility grid is operating and export current from the generator to a grid connector when the utility grid is not operating.

An apparatus for defining an AC power source having a predetermined amperage rating and for use with a pallet truck or fork lift lifting device. The apparatus includes a pair of terminal banks, a battery, a converter adapted to change DC to AC power, a relay, a controller, and a base adapted for engagement by the lifting device for transport of the apparatus. The apparatus is shaped so that it can be transported by the lifting device through a doorway. A pair of terminal banks, battery, converter, relay and controller are coupled to one another and configured for selective operation in a standalone configuration or a stacked configuration.