The present disclosure relates to an uninterruptible power supply (UPS) system and, more specifically, to a static transfer switch (STS) that can be applied to a UPS module, the static transfer switch comprising: one semiconductor rectifying element connected to either the anode terminal or the cathode terminal of a direct current power source; a bypass circuit for connecting the input terminal and the output terminal of the semiconductor rectifying element so as to bypass the semiconductor rectifying element; a breaker for opening or closing the bypass circuit; and a switch including a control unit, which controls the semiconductor rectifying element so as to conduct current when a preset conduction signal is received, controls the breaker so as to close the bypass circuit, and, when the bypass circuit is closed by the breaker, controls the semiconductor rectifying element so as to stop the conduction of current.

The present disclosure provides an electric steam control method, a system thereof, and a steam cleaner. The method includes: obtaining current water temperature data of a hot water tank and a current power supply mode; determining whether a temperature corresponding to the current water temperature data is within a preset temperature range; and if the temperature is within the preset temperature range, entering a heat preservation mode, else detecting whether AC power is currently available; if the AC power is available, performing power supply using the AC power, else generating a water temperature alarm signal; and in the heat preservation mode, detecting whether a working state is currently in place; if the working state is in place, detecting whether the AC power is currently available and generating a steam ejection signal, and performing power supply by using the AC or DC power, else maintaining the heat preservation mode.

Uninterruptible power supplies (UPS) and control methods are disclosed. The UPS can deliver power from a first source, such as AC grid power, under normal operating conditions and a from second source, such as batteries, if power from the first source is unavailable or unsuitable. The UPS can also allocate power to and among various connected loads and can supply supplemental power to a load if that load has surpassed its regular power allocation. For example, when the power output or demand from the loads exceeds the available incoming power from the first power source, supplemental power may be supplied from the second source. Thus, the UPS can support temporary surges in power demand by apportioning power among loads and by temporarily engaging all available power sources, if needed.

A backup power supply device is provided with: first to fifth battery packs connected in parallel; a charger that supplies a charge current to each battery pack; first to fifth charge switches that individually connect and disconnect charge paths of the respective battery packs; and a controller that controls each charge switch. The controller divides the battery packs into a plurality of groups and performs pulse-width modulation (PWM) control of each charge switch at a duty ratio corresponding to the number of batteries in each group to charge the battery packs for each group.

An uninterruptible power supply (UPS) system with stranded power recovery has a plurality of UPS modules with one or more of the UPS modules usable to provide stranded power to a recovered power bus. When a UPS module is used to provide stranded power to the recovered power bus, the AC/AC converter associated with that UPS module provides AC power that is synchronized with AC power being provided to the recovered power bus by each of the other AC/AC converters that are providing AC power. In this manner all of the AC/AC converters that are providing AC power to the recovered power bus have the same voltage, the same frequency, and are in phase.

A system and method of managing a power infrastructure having a plurality of duty power modules (DPMs) configured to power a plurality of load centers. Various different operational modes may be deployed. Inherent redundancy mode is implemented by: monitoring operations of the power infrastructure; powering each load center during normal operations using DPMs through a load center switch via an enabled preferred setting (PS) input; providing an inherent redundancy (IR) bus coupled to each load center switch via an alternate setting (AS) input that is disabled during normal operations, wherein the IR bus is configured to receive excess capacity power exclusively from the DPMs; and in response to a detected DPM failure, disabling the PS input and enabling the AS input in the load center switch for an affected load center to capture power from the IR bus.

A switch arrangement for providing alternative distribution paths in a system for distributing electrical power in a vehicle including electrical power supplies and electrical loads. The switch arrangement includes a first switch adapted to be connected to a first electrical element, a second switch adapted to be connected to the first electrical element and a second electrical element, and a third switch adapted to be connected to the electrical element and a third electrical element. Each of the first, second, and third switches is independently controllable, and selective operation of each of the first, second, and third switches to its open or closed state interconnects at least two of the first, second, and third electrical elements to establish one of multiple alternative distribution paths to connect one of the power supplies and one of the loads or to connect two of the power supplies.

Disclosed herein is a hybrid resonant capacitor circuit including a first capacitor configured to discharge resonant current to interrupt a load current to a switch in parallel with the hybrid resonant capacitor circuit, a second capacitor coupled in parallel with the first capacitor, wherein the second capacitor is configured to transfer energy stored in the second capacitor to the first capacitor after discharge of the resonant current from the first capacitor, and a current limiter coupled in series with the second capacitor. A static transfer switch including a thyristor switch and the hybrid resonant capacitor circuit is also disclosed herein, as is a method for facilitating multiple consecutive voltage source transfers between a first voltage source and a second voltage source powering a load, using the hybrid resonant capacitor circuit.

A power backup circuit provides a plurality of input power sources to back up a load. The power backup circuit includes a first switch, a second switch, and a control unit. The input power sources at least includes a first input power source and a second input power source. If the input power source of the load needs to be changed from the first input power source to the second input power source, the control unit controls the first switch to be coupled to the second input power source and controls the second switch to be coupled to the second input power source after the control unit effects a supply current flowing through a first power supply path and a second power supply path both coupled to the first input power source and the load to be reduced below a current threshold.

UPS systems, methods, and computer-readable mediums utilizing electromechanical bypass relays to switch from an on-line mode of operation to a green/bypass mode of operation include control logic to adaptively adjust the timing of when an inverter of a UPS turns off to prevent backfeeding a utility. After the UPS is instructed to transition from the on-line mode to the green mode, a monitoring period begins. During the monitoring period, a parameter related to the output current of the inverter is monitored and compared to a predetermined threshold. If the parameter exceeds the predetermined threshold before a fixed period time has elapsed, the inverter is turned off early. If the inverter current does not exceed the predetermined value within the fixed period of time, the inverter is turned off.