A wind turbine assembly including a rotor system, a generator, a first converter, a second converter, and a controller system. The first converter includes a first bridge circuit having a plurality of switch members each having a controllable switch. The second converter includes a second bridge circuit having a plurality of switch members each having a controllable switch. The controller system is adapted to provide a drying operation for second converter including short circuiting the second converter with the controllable switches of the second bridge in circuit, and supplying power from the generator through the first converter to the short circuited second converter for drying the second converter.

A VAR dispatch system. A central control system connected to a network is configured to receive data reflecting local variations in conditions on a power grid and to transmit system control commands over the network. A plurality of VAR dispatch devices are connected to the network and to the power grid. Each VAR dispatch device is configured to detect local variations in conditions on the power grid and to transmit the data reflecting such local variations to the central control system and to receive control commands from the central control system. Each VAR dispatch device is configured to store power and to output stored power to the power grid based on local variations in conditions on the power grid. Each VAR dispatch device is further configured to output stored power to the power grid when the VAR dispatch device receives system control commands from the central control system.

A liquid cooling power flow control system and related method are described. The system has switching assemblies for power flow control, in an enclosure. A pump circulates liquid coolant through a liquid cooling block to each switching assembly. The switching assemblies are electrically isolated from the enclosure.

The invention relates to an energy generating installation, especially a wind power station, comprising a drive shaft connected to a rotor (1), a generator (8) and a differential transmission (11 to 13) provided with three drives or outputs. A first drive is connected to the drive shaft, an output is connected to a generator (8), and a second drive is connected to an electrical differential drive (6, 14). The differential drive (6, 14) is connected to a network (10) by means of a frequency converter (7, 15) comprising an electrical energy accumulator in the direct-current intermediate circuit.

Methods, systems, controller devices, and computer program products for reactive power control at a renewable energy site are provided. Embodiments address dynamic performance problems associated with control loop delay and the changing modes of operation for meeting utility voltage and reactive power constraints. Provided is a method for reactive power control involving: (a) determining a site-wide reactive power command comprised by a sum of a reactive power feedforward or compensation term and an integrator term; and (b) distributing the site-wide reactive power command among inverters. Embodiments can include a reactive power control term based on the sum of a single integrator and reactive power compensation term, an integrator anti-windup mechanism based on the status of individual inverters, a means for decreasing detrimental effects of loop delay during reactive power reference changes, and/or a means of implementing voltage and power factor limits with smooth transfer between reactive power operating regions.

A power conversion device includes a smoothing capacitor, an input voltage detection unit, a power conversion unit, and a controller. The input voltage detection unit detects a voltage value of the input voltage. The power conversion unit converts a direct-current voltage smoothed by the smoothing capacitor into an alternating-current voltage to output the alternating-current voltage to a power system. The controller has a first operation mode of outputting active power to the power system, has a second operation mode of outputting reactive power to the power system, determines whether or not the voltage value is one of equal to and higher than a determination value, and makes a transition from the first operation mode to the second operation mode within a predetermined time from a time point when it is determined that the voltage value is lower than the determination value.

Described embodiments include a system and a method. A system includes an energy storage device configured to store and release energy. The system includes a waveform sensor configured to detect a second harmonic or higher frequency component deviation in a waveform of electric power supplied to the system by an electrical power grid. The system includes a bi-directional switched-mode converter coupled between the energy storage device and the electrical power grid. The switched-mode converter is configured to receive and convert electric power from the electrical power grid into energy stored in the energy storage device and to convert energy released from the energy storage device into electric power and discharge the converted electric power into the electrical power grid. The system includes a waveform correction manager configured to control the bi-directional switched-mode converter in a manner implementing a waveform deviation reduction strategy responsive to the detected deviation in the waveform.

The present invention provides a power control circuit connectable to a load adapted to receive a power supply, the power control circuit adapted to absorb power from the power supply and adapted to deliver power to the power supply to stabilize at least one electrical parameter of the power supply. The present invention also provides an associated method of stabilizing at least one electrical parameter of a power supply connectable to a load, the method including absorbing power from the power supply or delivering power to the power supply. The at least one electrical parameter of the power supply includes parameters such as voltage and frequency.

An illustrative example fuel cell power plant includes a cell stack assembly having a plurality of fuel cells configured to generate electricity based on an electrochemical reaction. The power plant includes a capacitor, a plurality of inverters, and at least one controller that is configured to control the plurality of inverters in a first mode and a second mode. The first mode includes the cell stack assembly associated with at least one of the inverters. A cell stack assembly and the associated inverter provide real power to a load external to the fuel cell power plant in the first mode. The second mode includes at least a second one of the inverters associated with the capacitor. The capacitor and the second one of the inverters selectively provide reactive power to or receive reactive power from a grid external to the fuel cell power plant in the second mode.

A device for reactive power compensation in a high voltage network having at least one phase conductor, includes a high voltage connection for each phase conductor, first and second core sections of a closed magnet circuit, a first high voltage winding enclosing the first core section, a second high voltage winding enclosing the second core section and being connected parallel to the first high voltage winding, at least one saturation switching branch being configured to saturate at least one core section has controllable power semiconductor switches, and a control unit controls the power semiconductor switches for each high voltage connection. In order to avoid leakage field losses, at least one high voltage winding has a central connection and is connected at its winding ends to the saturation switching branch. The central connection is connected to the high voltage connection.