Provide is a power conversion device capable of avoiding a power outage even if reference AC power is lost. A power conversion device 1 includes a phase detector 31 calculating a voltage phase based on the phase of AC power supplied to an electric power system 9, a waveform controller 35 generating a control signal designating the frequency and phase of the AC power based on the voltage phase calculated by the phase detector 31, a power conversion circuitry 12 which converts power supplied from a power supply source 15 into the AC power based on the control signal generated by the waveform controller 35, and which outputs the converted power to the electric power system 9, and a determination block 44 which detects the frequency of the AC power supplied to the electric power system 9, and which determines that the AC power that becomes the reference for the frequency is not supplied to the electric power system 9 when the detected frequency is not within a preset first frequency range. When the determination block 44 determines that the AC power that becomes the reference for the frequency is not supplied to the electric power system 9, the waveform controller 35 executes a control on the power conversion circuitry 12 so as to supply the AC power that becomes the reference for the frequency to the electric power system 9.

Provide is a power conversion device capable of avoiding a power outage even if reference AC power is lost. A power conversion device 1 includes a phase detector 31 calculating a voltage phase based on the phase of AC power supplied to an electric power system 9, a waveform controller 35 generating a control signal designating the frequency and phase of the AC power based on the voltage phase calculated by the phase detector 31, a power conversion circuitry 12 which converts power supplied from a power supply source 15 into the AC power based on the control signal generated by the waveform controller 35, and which outputs the converted power to the electric power system 9, and a determination block 44 which detects the frequency of the AC power supplied to the electric power system 9, and which determines that the AC power that becomes the reference for the frequency is not supplied to the electric power system 9 when the detected frequency is not within a preset first frequency range. When the determination block 44 determines that the AC power that becomes the reference for the frequency is not supplied to the electric power system 9, the waveform controller 35 executes a control on the power conversion circuitry 12 so as to supply the AC power that becomes the reference for the frequency to the electric power system 9.

Example unity power factor converter, (UPFC) operating methods and apparatus are described. In one example, the UPFC comprises a closed-loop control for regulation of an input current from a power grid in accordance with a reference variable for the input current. The UPFC is configured to determine amplitudes of frequency components of the input current, and establish a phase angle of the reference variable in dependence of a phase angle of a fundamental frequency component of an input voltage from the power grid and of the amplitudes of the frequency components.

Example unity power factor converter, (UPFC) operating methods and apparatus are described. In one example, the UPFC comprises a closed-loop control for regulation of an input current from a power grid in accordance with a reference variable for the input current. The UPFC is configured to determine amplitudes of frequency components of the input current, and establish a phase angle of the reference variable in dependence of a phase angle of a fundamental frequency component of an input voltage from the power grid and of the amplitudes of the frequency components.

A method and system for controlling the transfer of electrical power between a first electrical network and a second electrical network is disclosed. The method includes receiving at the second electrical network pricing information from the first electrical network, the pricing information associated with the supply of electrical power between the first electrical network and the second electrical network and modifying a demand characteristic of the second electrical network based on the pricing information.

A method and system are provided for transferring a load between a primary power source and a secondary power source. In accordance with the disclosure, a controller senses, via a sensor, an electrical signal providing power from the primary power source to the load. The controller also detects a non-conforming power event by determining that a parameter of the electrical signal is either more or less than a first threshold value. Responsive to the detection of the non-conforming power event, the controller determines a quantity of non-conforming power events that occur during a first time interval. The controller further can compares the determined quantity of non-conforming power events to a second threshold value. Responsive to the determined quantity of non-conforming power events being either greater or lesser than the second threshold value, the controller initiates a control signal, such as a control signal to initiate a load transfer.

A method and system are provided for transferring a load between a primary power source and a secondary power source. In accordance with the disclosure, a controller senses, via a sensor, an electrical signal providing power from the primary power source to the load. The controller also detects a non-conforming power event by determining that a parameter of the electrical signal is either more or less than a first threshold value. Responsive to the detection of the non-conforming power event, the controller determines a quantity of non-conforming power events that occur during a first time interval. The controller further can compares the determined quantity of non-conforming power events to a second threshold value. Responsive to the determined quantity of non-conforming power events being either greater or lesser than the second threshold value, the controller initiates a control signal, such as a control signal to initiate a load transfer.

A method and system are provided for transferring a load between a primary power source and a secondary power source. In accordance with the disclosure, a controller senses, via a sensor, an electrical signal providing power from the primary power source to the load. The controller also detects a non-conforming power event by determining that a parameter of the electrical signal is either more or less than a first threshold value. Responsive to the detection of the non-conforming power event, the controller determines a quantity of non-conforming power events that occur during a first time interval. The controller further can compares the determined quantity of non-conforming power events to a second threshold value. Responsive to the determined quantity of non-conforming power events being either greater or lesser than the second threshold value, the controller initiates a control signal, such as a control signal to initiate a load transfer.

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.

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.