Abstract: A regulation method for current limiting control, comprising: S1. regulating a current limiting threshold in real time based on a current limiting action: S2. controlling switch transistors based on the regulated current limiting threshold. By implementing the regulation method and device, it is made possible to regulate a current limiting threshold in real time directly based on a current limiting action, such that a current uprush in a first PWM wave will be significantly suppressed at the time of sudden loading or occurrence of a short circuit. Further, by regulating the current limiting threshold in real time based on the current limiting action and an inductive current, it is not only made possible to satisfy proper load-carrying capability, but also made possible to prevent a current uprush in a first PWM wave from being too high at the time of sudden loading or occurrence of a short circuit.

Abstract: The present disclosure relates to a system for controlling a supply air temperature adjustment for a cooling unit to optimize operation of the cooling unit with respect to at least one of room air temperature and humidity requirements. The system uses a controller for implementing: a machine learning module configured to select which portion or portions of acquired data pertaining to operation of the cooling unit will be utilized; and a neural network model which uses information supplied by the machine learning module and learns an operational behavior of the cooling unit, and wherein the machine learning module performs supervised learning and regression for the neural network model, and wherein the neural network model uses information supplied by the machine learning module for generating an output.

Abstract: Effects of a surge in an AC input voltage to a UPS is mitigated. If the AC input voltage is overvoltage, the rectifier is operated using a DC bus target voltage for the DC bus voltage unless the rectifier reaches its current limit. If the rectifier reaches its current limit, the DC bus target voltage is increased by a predetermined amount which is used as a current DC bus target voltage unless the increased DC bus target voltage exceeds a maximum DC bus voltage limit in which case the current DC bus target voltage is set to the maximum DC bus voltage limit. The rectifier is then operated using the current DC bus target voltage until it reaches its current limit or the AC input voltage surge has passed. If the rectifier again reaches its current limit, the above steps starting with increasing the DC bus target voltage are repeated.

Abstract: A method including: determining whether a cooling system is operating in a cooling mode, such that the cooling system is not operating in a reheat mode, a humidification mode or a dehumidification mode; determining whether the cooling system is operating in a compressor mode, such that the cooling system is not operating in a pump refrigerant economization mode; determining whether the cooling system is at steady-state; and if the cooling system is operating in the cooling mode and the compressor mode and is at steady-state, evaluating one or more rules to determine if a degradation symptom exists for the cooling system. The method further includes: subsequent to the evaluation, generating a degradation evaluation value to indicate whether the one or more rules are satisfied; and based on the degradation evaluation value, generating an alarm signal or performing a countermeasure.

Abstract: The present disclosure relates to a proportional, integral, derivative (PID) control system for controlling a cooling component of a cooling unit. The system may make use of a PID actuator position controller, a memory in communication with the PID actuator position controller, and a plurality of look-up tables. The look-up tables may be stored in the memory and may set forth different proportional “P”, integral (“I”) and derivative (“D”) gains based on an operating variable associated with operation of the cooling component of the cooling unit. The PID actuator position controller uses the lookup tables together with determination of projected data and historical data, to adjust at least one of the P, I and D gains in real time.

Abstract: The present disclosure is an apparatus for providing a multiple receptacle assembly whereby a number of receptacles could be configured within a single assembly of a standard size. It is contemplated that more receptacles may be available in a particular size and width than conventional power distribution units. Additionally, in another aspect of the present disclosure, the present disclosure is directed to an apparatus for providing power for multiple types of plugs via a single receptacle. In one embodiment of the disclosure, apparatus for providing power for multiple types of plugs via a single receptacle may provide power to one of a C14 plug or a C20 plug via a single receptacle, whereby the single receptacle may be configured to operate as a C13 and C19 receptacle and in compliance with IEC60320 standards.

Abstract: A method and device for controlling a two-wire discharge circuit of a battery, introducing a whole-bus voltage outer loop and an inductive current average value or inductive current actual value closed loop as a main control loop of the two-wire discharge circuit of the battery so as to guarantee a stable voltage of the whole bus. On the basis of the main control loop, duty ratios of switch transistors in respective discharge branches are adjusted to control the respective discharge branches to independently charge and discharge corresponding half-buses so as to balance the bus voltage. The method and the device avoid accessing a central wire of the battery and any additional circuits, and satisfy a technical specification of a three-wire access of the battery, thereby improving a circuit performance of the two-wire discharge circuit of the battery.

Abstract: The present disclosure relates to a modular DC power unit having a form factor enabling mounting in at least one of a plurality of component locations of an equipment rack. The modular DC power unit provides DC power to a DC bus of the equipment rack. The modular DC power unit may have a chassis defining a plurality of slots into which a plurality of DC power supplies may be inserted. An AC input module may be used for receiving AC power from an external AC power source. A plurality of independent, modular DC power supplies, each having a form factor enabling insertion and mounting in one of the slots of the chassis, may be mounted in the chassis. A controller may be in communication with the DC power supplies and housed within the chassis. A DC bus housed within the chassis communicates with the DC power supplies and supplies DC output power from the DC power supplies to the separate DC bus housed within the equipment rack.

Abstract: The present disclosure relates to a method for controlling a level of superheat during a pump mode of operation of a refrigeration system, wherein the refrigeration system can operate in either the pump mode or a compressor mode, and has an electronically controlled expansion valve (EEV). A controller obtains a stored, predetermined pump differential pressure range able to be produced by a pump of the system. The controller also obtains a stored, predetermined superheat range, and detects a superheat level. When the detected superheat level is outside of the superheat temperature range, the controller commands adjusting at least one of the EEV and a speed of the pump based on whether the detected superheat level is above or below the superheat range, and whether a current pump differential pressure is above or below the predetermined pump differential pressure range.

Abstract: The present disclosure is a method and apparatus to retrieve data from a power distribution unit. Apparatus to retrieve data from a power distribution unit may include a processor, memory and display which may be coupled to tracking circuitry of a power distribution unit in order to allow viewing of current operating conditions of the power distribution unit. In an embodiment of the disclosure, the processor may be configured to convert data from the tracking circuitry of the power distribution unit into a stream of character sets presented on the display which may be interpreted by a mobile device and translated by the mobile device into human readable information.

Abstract: A cooling system has both pumped refrigerant economization and direct expansion cooling. When outside air temperature is low enough that pumped refrigerant economization can provide enough cooling to satisfy cooling demand, only pumped refrigerant economization cooling is used to provide cooling. When outside air temperature is low enough that pumped refrigerant economization can provide some but not all of the cooling needed to satisfy cooling demand, the pumped refrigerant economization is operated at one hundred percent capacity and the direct expansion cooling is operated at a capacity to provide any supplemental cooling that is needed. If the outside air temperature is high enough that pumped refrigerant economization cannot provide any cooling, then only direct expansion cooling is used to provide cooling.

Abstract: A bidirectional resonant current-direct current conversion circuit and an uninterruptible power supply are provided. The bidirectional resonant current-direct current conversion circuit includes a full-bridge conversion module, a transformer, and a half-bridge conversion module. The full-bridge conversion module is coupled to the half-bridge conversion module via the transformer. The full-bridge conversion module is configured to convert two-level direct current power into alternating current power, and the half-bridge conversion module is configured to convert the alternating current power outputted by the full-bridge conversion module into three-level direct current power. The half-bridge conversion module is further configured to convert three-level direct current power into alternating current power, and the full-bridge conversion module is further configured to convert the alternating current power outputted by the half-bridge conversion module into two-level direct current power.

Abstract: A bidirectional resonant current-direct current conversion circuit and an uninterruptible power supply are provided. The bidirectional resonant current-direct current conversion circuit includes a full-bridge conversion module, a transformer, and a half-bridge conversion module. The full-bridge conversion module is coupled to the half-bridge conversion module via the transformer. The full-bridge conversion module is configured to convert two-level direct current power into alternating current power, and the half-bridge conversion module is configured to convert the alternating current power outputted by the full-bridge conversion module into three-level direct current power. The half-bridge conversion module is further configured to convert three-level direct current power into alternating current power, and the full-bridge conversion module is further configured to convert the alternating current power outputted by the half-bridge conversion module into two-level direct current power.

Abstract: The present disclosure relates to a computer based system for collecting, analyzing and presenting temperature information from sensors associated with an HVAC system. The system makes use of a processor for communicating with the plurality of sensors and obtaining temperature data reported by each of the sensors. A graphical user interface (GUI) module is provided which is embodied in a non-transient medium and configured to run on a computing device having a display screen. The user GUI module uses the temperature data, in real time, to generate a graph on the display screen. The graph includes a plurality of components each having different indicia to indicate groups of sensors that are below a predetermined lower temperature limit, above a predetermined upper temperature limit, and within a predetermined temperature range.

Abstract: A method reduces inrush currents in a transformer-less rectifier UPS system when an input circuit breaker of the UPS system is closed from an open position. The circuit breaker is coupled between an AC power input and an AC input of a rectifier of the UPS system and a DC output of the rectifier is coupled to a DC bus of the UPS system. Before the circuit breaker is closed, the DC bus is charged to a DC voltage having a level that is equal to a peak AC voltage level of a line-line AC voltage of AC input power to the UPS system. The rectifier is operated as an inverter to provide an AC output voltage at the AC input of the rectifier that is equal to an AC voltage at the AC power input and when it is equal, the circuit breaker is closed.

Abstract: A method is disclosed for analyzing performance of a chilled water (CW) system having a plurality of CW components. The method may consider a collection of at least one of allowable operating points, allowable operating ranges or allowable operating conditions, for each one of the CW components. A user set or system measured ambient wet bulb (WB) temperature may be considered for an environment in which at least a subplurality of the CW components are located. Equivalent loop conditions may be calculated for each of the CW components covering a load being thermally managed by the CW system. For each one of the calculated equivalent loop conditions, a processor may generate information for balancing the CW components to meet load requirements, and then analyze and select a balance condition that yields the user preferable optimization.

Abstract: The present disclosure relates to a load sharing system having a plurality of power supplies for powering a plurality of corresponding loads. Each one of the power supplies is associated with at least one of the loads. A power bus is also provided. A plurality of inductors is connected to the power bus. Each one of the inductors is further connected to at least one of the loads and to at least one of the power supplies, such that each adjacent pair of the inductors is connected in parallel relative to at least one of the loads. Each of the inductors has an inductance value sufficient so that if a fault develops on the power bus it serves to isolate the power supplies from the power bus. The inductance value further is such that if any one of the power supplies fails, the specific pair of inductors coupled in parallel to the load associated with the failed power supply allows the load to draw power over the power bus from other ones of the power supplies through the specific pair of inductors.

Abstract: A plenum pressure controlled cabinet includes a sideways cooled component mounted so as to define gaps between the cabinet and the component. Baffles block some of the gaps. A negative pressure maintained within the cabinet causes makeup air to be drawn into the cabinet through a gap not blocked by baffles between one side of the cabinet and a cool air intake of the component. Thus, cool air is provided to the cool air intake of the component. A plenum pressure controlled enclosure includes an equipment rack maintained at a neutral pressure, a plenum maintained at a slightly negative pressure or a neutral pressure, and a cooling unit. The plenum takes in air from the rack and expels it into the cooling unit. By controlling differential pressures in the rack and the plenum, air is efficiently drawn from the equipment rack and cooled utilizing the cooling unit.

Abstract: A cooling system for an equipment closet in a building has a direct expansion cooling circuit. The cooling system has two basic modes of operation. A first mode where the direct expansion cooling circuit is off and transfer air from an area of the building outside the equipment closet is used to cool the interior of the equipment closet without any cooling provided by the direct expansion cooling circuit and a second mode where the direct expansion cooling circuit is on and provides direct expansion cooling that is used to cool the interior of the equipment closet.

Abstract: A common mode choke in a 3-wire transformer free UPS system with which different rectifier and bypass power sources are used is eliminated by using different types of PWM control depending on whether the inverter is paralleled with the bypass power source. When the inverter is paralleled with the bypass power source, a type of PWM control is used that does not have common mode voltage injection. When the inverter is not paralleled with the bypass power source, a type of PWM control is used that has common mode voltage injection. In an aspect, the PWM control that does not have common mode voltage injection is sine-triangle PWM and the PWM control that has common mode voltage injection is space-vector PWM.