In an embodiment, an airport electric vehicle charging system includes a current transducer electrically coupled with a power source; a solid state converter electrically coupleable with an aircraft at or near an airport gate and configured to provide and maintain power to the aircraft; and a controller. The system further includes a first feedback loop between the controller and the current transducer; a second feedback loop between the controller and the solid state converter; and a battery charger electrically coupled with the power source and configured to charge one or more electric vehicles. The first feedback loop provides a first feedback signal generated by the current transducer to the controller. The second feedback loop provides a second feedback signal generated by the solid state converter to the controller. The battery charger is configured to consume power from the power source in accordance with the first and second feedback signals.

A power conversion system includes: a power converter connected between a DC power source and an AC power source; an AC switch connected between the power converter and the AC power source; an AC capacitor connected on the power converter side relative to the AC switch, on an output side of the power converter; and a control device configured to, in a state in which the AC switch is open, recognize a voltage of the AC capacitor and control the power converter to bring an output voltage of the power converter close to a voltage of the AC power source from the voltage of the AC capacitor gradually or in a step-by-step manner, and then close the AC switch. The power conversion system can suppress overcurrent at a time of start-up of a power converter and inrush current at a time of interconnection to an AC power source.

A load balancing apparatus for balancing the current supplied on each phase of a multiple phase supply, Each supply phase feeds an AC load, as well as an AC-DC converter. The apparatus measures the current supplied from each phase of the supply as well as the power consumed by each of the AC loads. The power consumed by each of the AC-DC converters is adjusted so that the sum of the current drawn by any one of the AC loads, plus the current drawn by the AC-DC converter on the same supply phase, is substantially balanced between the supply phases. Typically the AC-DC converters supply a common DC battery. In some embodiments each AC load includes a DC-AC converter configured to supply power from the common DC battery to one or more of the AC loads.

A load balancing apparatus for balancing the current supplied on each phase of a multiple phase supply, Each supply phase feeds an AC load, as well as an AC-DC converter. The apparatus measures the current supplied from each phase of the supply as well as the power consumed by each of the AC loads. The power consumed by each of the AC-DC converters is adjusted so that the sum of the current drawn by any one of the AC loads, plus the current drawn by the AC-DC converter on the same supply phase, is substantially balanced between the supply phases. Typically the AC-DC converters supply a common DC battery. In some embodiments each AC load includes a DC-AC converter configured to supply power from the common DC battery to one or more of the AC loads.

The invention relates to a power plant controller for controlling wind turbine generators. More particularly, the invention relates to a method for compensating data obtained from measurements at a connection point to the grid in case of a communication failure where communication of such data is lost or becomes unreliable. The measured data are used in the power plant controller for determining setpoints for controlling the wind turbine generators' production of active and reactive power. In response to detection of a communication fault a new setpoint is determined independently of new measured grid data by reconfiguring parts of the power plant controller.

A power distribution system includes at least two DC buses and at least two AC buses and a plurality of converter units interconnecting the DC buses and the AC buses in a ring. The system may further include one or more AC power sources (e.g., utility feeds, engine-generator sets, etc) connected to selected ones of the AC buses and/or one or more DC power sources (batteries, capacitor banks, fuel cells, etc.) connected to selected ones of the DC buses. The ring configuration can support a variety of AC and DC loads and provide redundancy and power distribution among the power sources.

An electrical system for an automotive vehicle has a plurality of electrical generating machines having field windings energized by pulse width modulated drive signals generated by an external electronic voltage regulator. The pulse width modulated drive signals have a duty cycle determined by the electronic voltage regulator. A controller selects one of electrical generating machines to evaluate for failure and evaluates that electrical generating machine for failure by causing the PWM drive signal for the field windings of that electrical generating machine to be disabled. The controller then determines that this electrical generating machine has failed if the duty cycle for the PWM drive signals has then not been increased by the electronic voltage regulator by a pre-determined amount. The electrical generating machines are either generators or alternators. In an aspect, the PWM drive signals for the plurality of electrical generating machines are out of phase with each other.

An electrical system for an automotive vehicle has a plurality of electrical generating machines having field windings energized by pulse width modulated drive signals generated by an external electronic voltage regulator. The pulse width modulated drive signals have a duty cycle determined by the electronic voltage regulator. A controller selects one of electrical generating machines to evaluate for failure and evaluates that electrical generating machine for failure by causing the PWM drive signal for the field windings of that electrical generating machine to be disabled. The controller then determines that this electrical generating machine has failed if the duty cycle for the PWM drive signals has then not been increased by the electronic voltage regulator by a pre-determined amount. The electrical generating machines are either generators or alternators. In an aspect, the PWM drive signals for the plurality of electrical generating machines are out of phase with each other.

According to one aspect, embodiments of the invention provide a system for monitoring a load center including a plurality of current sensors, a communication bus, a plurality of sensor circuits, a power module configured to be coupled to a load center input line and to receive input AC power from the input line, a collector, and a cable configured to be coupled between the power module and the collector, wherein the power module is further configured to provide power to the plurality of sensor circuits via the communication bus, provide power to the collector via the cable, measure at least one of voltage, frequency and phase of input AC power and provide signals related to the measured voltage, frequency or phase to the collector via the cable, receive current measurement signals from the plurality of sensor circuits and provide the received current measurement signals to the collector via the cable.

According to one aspect, embodiments of the invention provide a system for monitoring a load center including a plurality of current sensors, a communication bus, a plurality of sensor circuits, a power module configured to be coupled to a load center input line and to receive input AC power from the input line, a collector, and a cable configured to be coupled between the power module and the collector, wherein the power module is further configured to provide power to the plurality of sensor circuits via the communication bus, provide power to the collector via the cable, measure at least one of voltage, frequency and phase of input AC power and provide signals related to the measured voltage, frequency or phase to the collector via the cable, receive current measurement signals from the plurality of sensor circuits and provide the received current measurement signals to the collector via the cable.