US 8,552,589 B2 · Digital control method for operating the UPS systems in parallel

Abstract

Systems and methods of operating uninterruptible power supplies in parallel in a power distribution system to provide power to a load are provided. At least one uninterruptible power supply inverter provides power to the load. A communication interface provides a measured value of at least one of inverter output current of a first uninterruptible power supply and a measured value of the load current to a second uninterruptible power supply, and receives a measured value of at least one of inverter output current of the second uninterruptible power supply and the load current. A controller controls the uninterruptible power supplies to operate in one of a master state and a slave state. In the master state the uninterruptible power supply is configured to control the voltage to the load, and in the slave state the uninterruptible power supply is configured to determine a reference output current value based at least in part on at least one of the measured value of inverter output current of the second uninterruptible power supply and the measured value of the load current. The uninterruptible power supply in the slave state drives its inverter output current toward the reference output current value to provide its share of the load current.

Claims19

Dependent claims

An uninterruptible power supply configured to operate in parallel with a second uninterruptible power supply in a power distribution system, the uninterruptible power supply comprising:

an inverter configured to provide power to a load;
a communication interface configured to provide a measured value of inverter output current of the uninterruptible power supply to the second uninterruptible power supply, and to receive a measured value of inverter output current of the second uninterruptible power supply;
and
a controller coupled to the inverter and the communication interface and configured to control the uninterruptible power supply to operate in one of a master state and a slave state, wherein in the master state the uninterruptible power supply is configured to control voltage to the load, and in the slave state the uninterruptible power supply is configured to determine a reference output current value based the measured value of inverter output current of the second uninterruptible power supply and to drive inverter output current of the uninterruptible power supply toward the reference output current value.

1 more element

A method of distributing power using an uninterruptible power supply configured to operate in parallel with a plurality of uninterruptible power supplies including a second uninterruptible power supply to provide power to a load, comprising:

controlling the uninterruptible power supply in one of a master state and a slave state;
controlling, with the uninterruptible power supply in the master state, voltage to the load;
providing, with the uninterruptible power supply in the master state, a measured value of output current of the uninterruptible power supply to the plurality of uninterruptible power supplies;
receiving, with the uninterruptible power supply in the slave state, a measured output current value of the second uninterruptible power supply;
determining, with the uninterruptible power supply in the slave state, a reference current value of the uninterruptible power supply based on the measured output current value of the second uninterruptible power supply;
and
driving an inverter output current of the uninterruptible power supply toward the reference current value.

4 more elements

Dependencies are inferred from the claim text.

Digital control method for operating the UPS systems in parallel

Life of this patent

Digital control method for operating the UPS systems in parallel

Life of this patent

Abstract

Claims19