Liebert Corporation

Vertiv Corporation

Xian Chen

Brian Paul Heber

Terry Dwane Bush

Charles F Blair

Gregory W Ratcliff

Kevin Kim Eschhofen

Paul Taylor

Kaiyu Wang

Matthew Elswick

Matthew Gambill

A power control system may include an uninterruptible power supply (UPS), a display device, load measurement circuitry to determine a load percentage of the UPS, and a controller. The controller may receive the load percentage of the UPS from the load measurement circuitry; monitor the load percentage of the UPS to determine whether the UPS is operating in a nominal load state or an overload state; generate an input overload countdown timer when the UPS is operating in the overload state, where the input overload countdown timer provides an estimated time remaining in the overload state; generate an output overload countdown timer by applying a minimum envelope filter to the input overload countdown timer; and direct the display device to display the output overload countdown timer. Additionally, the minimum envelope filter may be operated in an open-loop or a closed-loop configuration.

UPS overload time remaining calculation based on an adaptive minimum envelope filter

In some embodiments, apparatuses and methods are provided herein useful to operating uninterruptible power supplies (UPS). The embodiments may include a plurality of capacitor banks, a UPS control circuit, and a central control circuit. The UPS control circuit is configured to cause an output of a clean electrical power, sample the clean electrical power, calculate control algorithm outputs based on the sampled clean electrical power, and output control algorithm results to the central control circuit. The central control circuit configured to detect a degradation of the plurality of capacitor banks, and transmit a service alert in response to the detection of the degradation of the plurality of capacitor banks.

Systems and methods for operating an uninterruptible power supply (UPS)

A device may include an rectifier with one or more transistors that accepts a three-phas7 input and generates a DC bus output, a low-pass filter to provide a filtered DC bus voltage, a driver to drive the transistors based on a modulation index, and a controller to generate the modulation index. The controller may generate a nominal modulation index, generate an adjusted modulation index based on the nominal modulation index modified by a ratio of the filtered and measured DC bus voltages, and provide the modulation index to the PWM driver, where the modulation index is the nominal modulation index when a difference voltage associated with a difference between the filtered and measured DC bus voltages is below a voltage threshold, and where the modulation index is the adjusted modulation index when the difference voltage is above the voltage threshold.

Intelligent rectifier current regulation of DC bus voltage droop

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.

Method of mitigating effects of AC input voltage surge in a transformer-less rectifier uninterruptible power supply system

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.

Method to reduce inrush currents in a transformer-less rectifier uninterruptible power supply system

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.

Method to select optimal synchronization source in a multiple uninterruptible power supply system

A multiple UPS system includes a plurality of multi-module UPS subsystems coupled to a power tie cabinet, each multi-module UPS subsystem having a plurality of UPS modules. The power tie cabinet includes one or more controllers, collectively referred to as PTC (power tie cabinet) controls. The PTC controls periodically determine a power error message for each of the multi-module UPS subsystems and pass it to the respective multi-module UPS subsystem. A controller of the multi-module UPS subsystem uses the power error message to determine error data that is provided to a power average control loop used in control of power sharing among the UPS modules of the multi-module UPS subsystem.

Multiple UPS system having multi-way power tie system and intelligent power sharing control

A multiple UPS system has a plurality of UPS subsystems with a separate UPS data communications bus coupling a controller of each UPS subsystem to an associated controller of an associated tie cabinet. The multiple UPS system further includes a data communications tie bus that couples the controllers of the tie cabinets to each other. The controllers of the tie cabinets arbitrate power line based coordinating signals between the UPS buses without the use of auxiliary signals.

Intelligent arbitration of power line based coordinating signals between multiple UPS buses without any auxiliary signals

A repetitive servomechanism controller for a UPS system has an inner control loop and an outer control loop. The inner control loop regulates inverter current and the outer control loop regulates inverter voltage. The outer control loop includes a repetitive controller in combination with a harmonic servomechanism controller and a feed-forward controller.

Repetitive servomechanism controller for uninterruptible power supply system

An uninterruptible power supply (UPS) system has an inverter having an output coupled to a primary side of an output transformer. The UPS system has a controller having a dual gain voltage regulator for controlling the output voltage of the inverter of a UPS system that uses active and reactive current components of a load current flowing out an output of the UPS system.

Uninterruptible power supply with a dual gain voltage regulator controlling an inverter output voltage based on active and reactive components of current

Existing measurements of an input component (such as voltage or current) in a three phase power supply system are decomposed into a negative sequence component. The negative sequence component, which is significantly higher when a rectifier fuse is blown, is compared to a threshold and a determination made that a rectifier fuse is blown when the negative component exceeds the threshold. In an aspect, an adaptive algorithm is used to make the detection work better in the range of the nominal frequency of the input voltage. In an aspect, the negative sequence is determined indirectly from the existing measurements.

Power supply system with adaptive blown fuse detection using negative sequence component

An uninterruptible power supply ('UPS') has a phase-controlled rectifier coupled to a source of AC power and having an output providing a DC bus, the output of the phase-controlled rectifier coupled to an inverter. A first controller generates a firing angle for the rectifier and a fuzzy logic controller generates a firing angle for the rectifier. In an aspect, the rectifier is controlled by the firing angle generated by the first controller during normal operating conditions of the UPS and the rectifier is controlled by the firing angle generated by the fuzzy logic controller during abnormal operating conditions of the UPS. The abnormal operating conditions can include loss of a direct DC bus voltage measurement and or a period of time after the UPS experiences a large load change. In an aspect, the firing angle generated by the first controller is compared to the firing angle generated by the fuzzy logic controller and a rectifier fault condition determined to exist when the two firing angles differ by at least a threshold amount. In an aspect, the first controller is a PI controller.

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Columbus, OH, United States of America

Xian Chen