Abb Schweiz Ag

General Electric Company

Andrea Mannuccini

Silvio Colombi

Lorenzo Giuntini

Harry Bye Handlin

Luigi De Bernardi

Andrea Lauro Delmue'

Giosue' Claudio Rebuffoni

Giosue Claudio Rebuffoni

Silivo Colombi

Andrea Lauro Delmue

The disclosure relates to a method for controlling an uninterruptable power supply and a respective computer program. The uninterruptable power supply comprises a grid connection, a grid switch connected to the grid connection, a rectifier and an inverter interconnected via a DC link, an energy storage connected to the DC link, a load connection, to which the inverter is connected, and a bypass switch, which is connected in parallel to the rectifier, the DC link and the inverter between the grid switch and the load connection, wherein the grid switch is a mechanical switch and the bypass switch is a semiconductor switch.

Method for controlling an uninterruptable power supply

A method for controlling an uninterruptable power supply arranged between a grid and a variable load, the uninterruptable power supply includes a DC link interconnecting a rectifier connected to the grid via a grid switch, an energy storage and an inverter connected to the load, and a switchable bypass connected between the grid switch and the load and in parallel with the path formed by the rectifier, the DC link and the inverter, the method includes monitoring a power supply of the grid, comparing the power supply to a load requirement of the load, if the power supply meets the load requirement, closing the grid switch, and switching on the bypass, to supply the load with AC current from the grid.

An uninterruptible power supply (UPS) is provided that includes a split direct current (DC) link having a first capacitor coupled between a positive DC link terminal and a first node, and a second capacitor coupled between the first node and a negative DC link terminal. The UPS also includes a rectifier coupled to an input of the split DC link and a controller coupled to the rectifier. The rectifier includes first, second, and third legs, wherein each leg is configured to convert a first alternating current (AC) voltage received from an AC source into a DC voltage to be provided to the split DC link, and a fourth leg configured to balance DC link voltages of the first and second capacitors. The controller is configured to maintain functionality of the rectifier during at least one of a partial utility power outage, a full utility outage, and a failure of at least one of the first, second, third, and fourth legs.

Uninterruptible power supply and method of operation

An uninterruptible power supply (UPS) system is provided. The UPS system includes a plurality of UPSs, a ring bus coupled to the UPSs, a plurality of chokes, and at least one static switch coupled between an associated UPS of the UPSs and the ring bus. Each choke electrically couples an associated UPS to the ring bus. The static switch is switchable to selectively bypass at least one choke.

Isolated parallel UPS system with choke bypass switch

In at least one embodiment, a system may include a plurality of uninterruptible power supplies (UPSs), a ring bus, a plurality of chokes, with each choke of the plurality of chokes electrically coupling an associated UPS of the plurality of UPSs to the ring bus, and at least one switch electrically coupled between at least one UPS of the plurality of UPSs and the ring bus, with the at least one switch having an opening time of less than 10 milliseconds.

Protection methods and switches in uninterruptible power supply systems

A control system and methods for a multilevel power converter are provided. The converter includes a rectifier coupled to a DC link having a midpoint coupled to electrical ground that divides the DC link into two halves. The control system is configured to generate a reference current command for controlling an output of the rectifier, the reference current command generated based on a difference between a desired and measured DC link voltage value. The system is also configured to determine a zero-sequence current component of input current supplied to the multilevel power converter, wherein the zero-sequence current component is associated with non-linearities in said multilevel power converter that cause ground current injection into the input current by the rectifier. The system is further configured to subtract the determined zero-sequence current component from the reference current command to reduce the ground current injected into the input current by the rectifier.

Method and control system for zero-sequence current compensation for ground current reduction

A system is provided. The system includes a plurality of uninterruptible power supplies (UPSs), each UPS of the plurality of UPSs including an inverter, a ring bus, and at least one controller communicatively coupled to the plurality of UPSs, the at least one controller configured to determine when a bridge current in at least one UPS of the plurality of UPSs reaches a predetermined bridge current limit, and modify, in response to the determination, a capacitor voltage in the inverter of the at least one UPS to reduce a DC fault current component of a load current in the inverter.

Systems and methods for hybrid voltage and current control in static UPS systems

An uninterruptible power supply (UPS) system is provided. The UPS system includes a plurality of UPSs, a ring bus that electrically couples the UPSs together, a static switch coupled between an associated UPS of the UPSs and the ring bus, and a controller. The controller receives current data representative of an inverter current and a load current associated with the associated UPS. An output capacitor of the associated UPS is coupled to a node that conducts the inverter current and the load current. The controller further calculates a measured current based on the received current data, determines a voltage of said output capacitor, generates a derived current based on the determined voltage and a predetermined capacitance of said output capacitor, compares the measured current and the derived current to identify a fault location, and controls said static switch based on the identified fault location.

Isolated parallel ups system with fault location detection

A system is provided. The system includes a plurality of uninterruptible power supplies (UPSs), a ring bus, a plurality of chokes, each choke of the plurality of chokes electrically coupling an associated UPS of the plurality of UPSs to the ring bus, and at least one switch electrically coupled between at least one UPS of the plurality of UPSs and the ring bus, the at least one switch having an opening time of less than 10 milliseconds.

A system is provided. The system includes a plurality of uninterruptible power supplies (UPSs), each UPS of the plurality of UPSs including an inverter, a ring bus, and at least one controller communicatively coupled to the plurality of UPSs, the at least one controller configured to control at least one bridge current in each UPS, the at least one bridge current controlled such that the inverter of each UPS operates in a partial current limiting regime between a full current limiting regime and a linear mode.

Systems and methods for exploiting current capability in static ups

A power conversion system is provided. The power conversion system includes a plurality of power conversion modules connected in parallel, all power conversion modules of the plurality of power conversion modules configured to receive a pulse-width modulation control signal, each power conversion module of the plurality of power conversion modules including a current unbalance detection circuit configured to calculate a difference between a reference current and an output current of the power conversion module, and a processing device communicatively coupled to the current unbalance detection circuit and configured to perform processing using the calculated difference.

Systems and methods for advanced diagnostic in modular power converters

A system is provided. The system includes a plurality of uninterruptible power supplies (UPSs), a ring bus, and at least one controller communicatively coupled to the plurality of UPSs, the at least one controller configured to calculate an output voltage frequency for each UPS of the plurality of UPSs, wherein the output voltage frequency for a UPS of the plurality of UPSs is calculated based at least on a derivative of an average active output power of the UPS, and control operation of each UPS based on the respective calculated output voltage frequencies.

Systems and methods for managing power backfeed in uninterruptible power supply systems

A system is provided. The system includes a ring bus, at least one voltage source, and a plurality of uninterruptible power supplies (UPSs) electrically coupled between the at least one voltage source and the ring bus, wherein at least one UPS of the plurality of UPSs includes an input, an output, a rectifier having a rectifier input and a rectifier output, an inverter having an inverter input and an inverter output, wherein the rectifier output is electrically coupled to the inverter input, and a bypass switch electrically coupled between the rectifier input and the inverter output, the bypass switch configured to close in response to detection of a fault on the ring bus.

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Locarno, Switzerland

Andrea Mannuccini