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: 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 is provided for detecting a failure of a rectifier or a rectifier source in context of an uninterruptible power supply. The method includes: measuring an input current into the rectifier from a primary power source; determining a rate of change in the measured current; determining a current difference between a reference current and the measured current; measuring voltage output by the rectifier; determining a voltage difference between a reference voltage and the measured voltage; and detecting a failure condition of the rectifier as a function of the measured input current, the rate of change in the measured current, the current difference, the measured voltage and the voltage difference. More specifically, a failure condition of the rectifier is identified when the input current is decreasing and the rate of change in the measured current is decreasing and the current difference is increasing and the voltage difference is increasing.

Abstract: A cooling system has a cabinet and a plurality of separate cooling stages including an upstream cooling stage and a downstream cooling stage. At least the upstream cooling state is a variable capacity cooling stage. Each cooling stage has a cooling circuit. Evaporators of the cooling circuits are arranged in the cabinet so that air passes over them in serial fashion. A controller when a Call for Cooling first reaches a point where cooling is needed, operating the upstream cooling circuit to provide cooling and not the downstream cooling circuit. When the Call for Cooling has increased to a second point, the controller additionally operates the downstream cooling circuit to provide cooling. The cooling capacity at which the upstream cooling circuit is being operated is less than its full capacity when the Call for Cooling reaches the second point.

Abstract: In an aspect, a cooling system has a cooling circuit that includes an evaporator, a condenser, a compressor, a sub-cooler and an expansion device configured in a direct expansion cooling circuit with the sub-cooler coupled in series between an outlet of the condenser and an inlet of the expansion device. The condenser has a micro-channel cooling coil and the sub-cooler has a fin-and-tube cooling coil. In an aspect, the fin-and-tube cooling coil of the sub-cooler has a total hydraulic volume equivalent to the total hydraulic volume of the micro-channel cooling coil of the condenser but the fin-and-tube cooling coil of the sub-cooler has a face area more than two times smaller than a face area of the micro-channel cooling coil of the condenser.

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: A real current meter reads current from a current probe coupled around power lines of a transformer-based UPS system coupled to a transformer having a high resistance ground with a HRG resistance and determines a real current component of the current read from the current probe.

Abstract: When the preferred voltage source for a static transfer switch is a UPS, there can be a brief interruption in the voltage received from the UPS while the UPS is switching from economy mode to normal mode. Operation of the static transfer switch can be improved during such voltage disturbances. Specifically, the static transfer switch may be in data communication with the UPS and thereby made aware that the voltage disturbance is temporary. As a result, the static transfer switch can avoid an unnecessary transfer to an alternate voltage source.

Abstract: A modular data center system is disclosed for constructing a modular data center building. A plurality of structural support columns are used to support a plurality of unit structures above a floor surface at a desired height relative to the floor surface. A pair of elongated support rails are also included which are coupled perpendicularly to the plurality of structural support columns, at approximately the desired height, to form two parallel, horizontally spaced apart tracks. Each of the unit structures includes a plurality of carriage assemblies, with each of the carriage assemblies including a wheel. The wheels allow the unit structures to be rolled horizontally into a desired position on the pair of elongated support rails when constructing the modular data center building to expedite its assembly.

Abstract: A cooling system has a direct expansion mode and a pumped refrigerant economizer mode and a controller. The controller includes a load estimator that estimates real-time indoor load on the cooling system and uses the estimated real-time indoor load to determine whether to operate the cooling system in the pumped refrigerant economizer mode or in the direct expansion mode.

Abstract: A multiple uninterruptible power supply system includes at least two uninterruptible power supply modules. Each uninterruptible power supply module has a control unit with the control unit coupled to a synchronization bus. The uninterruptible power supply module are synchronized to each other with one of the uninterruptible power supply modules being operated as a sync master UPS and its control unit sending synchronization signals on the synchronization bus that are received on the synchronization bus by control units of each of the other uninterruptible power supply module which are each operated as a slave UPS synchronized to the sync master UPS. When a bypass power source for the uninterruptible power supply module that is being operated as the sync master becomes unqualified, another one of the UPS modules is operated as the sync master and its control unit then sends out the synchronization signals.

Abstract: A method including: determining a cooling value; and comparing the cooling value to an activation point of a lead compressor. The lead compressor is in a tandem set of scroll compressors of a cooling system. The tandem set of compressors comprises a lag compressor. The method further includes: activating the lead compressor when the cooling value is greater than the activation point; activating the lag compressor subsequent to activating the lead compressor; and determining whether conditions exist including: an alarm associated with the lag compressor being generated, and the lead compressor being deactivated. The method further includes deactivating the lag compressor when at least one of the conditions exists in the cooling system.

Abstract: A cooling system for transferring heat from a heat load to an environment has a volatile working fluid. The cooling system includes first and second cooling cycles that are thermally connected to the first cooling cycle. The first cooling cycle is not a vapor compression cycle and includes a pump, an air-to-fluid heat exchanger, and a fluid-to-fluid heat exchanger. The second cooling cycle can include a chilled water system for transferring heat from the fluid-to-fluid heat exchanger to the environment. Alternatively, the second cooling cycle can include a vapor compression system for transferring heat from the fluid-to-fluid heat exchanger to the environment.

Abstract: A system includes an error module configured to integrate a difference between a superheat signal and a superheat setpoint to generate an error signal, wherein the superheat signal indicates suction superheat values of a compressor. A comparison module is configured to compare the error signal to a first predetermined threshold to generate a first comparison signal based on the comparison. A zero-crossing module is configured to compare a first count value to a second predetermined threshold to generate a second comparison signal. The first count value is generated based on at least one comparison between the superheat signal and the superheat setpoint. A setpoint module is configured to adjust the superheat setpoint based on the first comparison signal and the second comparison signal.

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 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: A hybrid air handler cooling unit has a bi-modal heat exchanger. In a direct expansion mode or a pumped refrigerant economization mode, the bi-modal heat exchanger is in a refrigerant path in parallel with first and second condenser coils and functions as a condenser coil. In a mixed direct expansion/pumped refrigerant economization mode, the bi-modal heat exchanger is in a refrigerant path in series between an outlet of a pump and an inlet of the first condenser coil and functions as a pre-cooler evaporator coil with return air first flowing across the bi-modal heat exchanger and then across an evaporator coil of an evaporator.

Abstract: A system including a transceiver that is in a first device and receives wirelessly or over a powerline and from a second device, (i) a voltage value of a voltage detected between bus bars of a power source, where the power source supplies power to a load, and where the load is distinct from the first and second devices, or (ii) a current value of a current detected by a current sensor and drawn from the power source by the load. A sensing module one of (i) if the transceiver receives the current, detects the voltage and timestamps the voltage value with a first timestamp, and (ii) if the transceiver receives the voltage, determines the current and timestamps the current value with a second timestamp. A parameter module determines a parameter of the load based on the voltage, the current, and the first and second timestamps.

Abstract: The present disclosure relates to a processor based system for using temperature information being reported by a plurality of sensors present within a predetermined environment and controlling how various ones of the sensors are grouped together into a plurality of groups for monitoring purposes. The system includes a software subsystem that generates an association matrix screen on a display system associated with a computer system being used by a user with receives the temperature information. The association matrix screen enables a user to associate or disassociate specific sensors with selected groups of sensors using selection commands, as well as to provide temperature related information concerning all of the sensors being monitored by the system. Each of the sensors is not limited to being assigned to only a single group of sensors but may instead be assigned to two or more different groups of sensors for purposes of monitoring and/or control.

Abstract: A pumped refrigerant cooling system having multiple pumping units for providing working fluid to a load to enable cooling of a space via the load. The pumped refrigerant cooling system operates the pumping units at less than capacity. When a pumping unit is deactivated, the output of the remaining pumping units is increased to maintain fluid flow.