Device for controlling solar driven water pumps with three selectable modes on the control panel being: I) speed mode with 100% use of the available solar DC power at all times; II) solar mode using available solar DC power only, and III) eco mode combining the use of the available solar DC power with the use of the AC power from a grid or a generator and/or batteries, by automatic switching between two stages, being (i) solar stage running on solar DC power only, and (ii) hybrid stage running with solar DC power and AC power from grid or generator and/or batteries like in speed mode. The purpose of the present disclosure is to preferentially use solar energy from solar panels over AC current from the electric grid or from a generator and/or batteries while ensuring sufficient pumping capacity.

A circuit (100) for use in voltage supply for an electrical device, having a first input (111) configured for connecting with a first voltage source, a second input (121) configured for connecting with a second voltage source, and a common output (133) configured for connecting with an input of the electrical device, comprising a first voltage converter (110) with an input connected to or being the first input (111), and configured to provide DC voltage at a first voltage level (V.sub.1) at an output (113), further comprising a second voltage converter (120) with an input connected to or being the second input (121), and configured to provide DC voltage at a second voltage level (V.sub.2) at an output (123), wherein the second voltage converter (120) is configured not to operate when a voltage level present at its output (123) is higher than a stop threshold, and to operate when a voltage level present at its output (123) is lower than a start threshold, the stop threshold is equal to or higher than the second voltage level (V.sub.2) and lower than the first voltage level (V.sub.1), and the start threshold is equal to or lower than the second voltage level (V.sub.2).

The control circuit for a system provided with a power converter of multi-phase rotating electric machine, and is provided with a switch driving unit that drives the upper and lower arm switches based on the switching command to drive the rotating electric machine, an emergency power source that generates power with a power supplied from the power storage unit, an abnormality determination unit that determines whether a failure occurs in the control circuit, and an emergency control unit that performs, when the emergency determination unit determines that a failure occurs in the control circuit, a short circuit control in which either the upper arm switches or the lower arm switches are turned ON and the other arm switches are turned OFF by using the emergency power generated by the emergency power source.

Provided is a system for uninterrupted power using an array of capacitive elements (e.g., ultra-capacitors). The system may include an input, which may receive power from a first power source. A direct current (DC) bus may be connected to the input and may receive power from the input. An array of capacitive elements (e.g., ultra-capacitors) may be connected to the DC bus. An output may be connected the DC bus. The output may include an alternating current (AC) power supply, which may supply power to at least one facility. At least one controller may control charging and discharging of the array of capacitive elements (e.g., ultra-capacitors) connected to the DC bus to supply power from the DC bus to the output. A method and computer program product are also disclosed.

Embodiments include redundant power supplies and method for fault detection in a redundant power supply. Aspects include monitoring a voltage at local output nodes of each phase of the redundant power supply, wherein the local output nodes are each connected to an output bus of the redundant power supply via a feedback path. Aspects also include creating an alert that a phase associated with the local output node has failed based on a determination that the voltage at the local output node is within a fault range.

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.

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.

Embodiments of the present disclosure provide a server cabinet power backup system and a testing method thereof. In a self-test process of the power backup unit, the battery management module may be configured to: control the battery pack to supply power to the self-test resistor to discharge the battery pack, control the battery pack to be charged after the battery pack is discharged, and collect a charge and discharge parameter of the battery pack, and the battery management module may be further configured to: determine attenuation performance of the power backup unit according to the charge and discharge parameter of the battery pack.

The present disclosure comprises an alternating current-to-direct current converter for converting a commercial power current; a direct current-to-direct current converter for converting a battery current; a common output end at which the output end of the alternating current-to-direct current converter and the output end of the direct current-to-direct current converter are connected through a link capacitor having a preset bus voltage; a first circuit breaking part for opening or closing the current path between the common output end and a load; a second circuit breaking part for opening or closing the current path between the commercial power and the alternating current-to-direct current converter; a third circuit breaking part for opening or closing the current path between the battery and the direct current-to-direct current converter; and a control unit.