Provided is a method for controlling a wind power installation and/or a wind farm having at least one wind power installation, particularly in the case of asymmetrical network voltages, comprising: measuring a first voltage of a first phase, a second voltage of a second phase and a third voltage of a third phase of a three-phase electrical system, calculating a symmetrical negative-sequence voltage system from the measured voltages including a first negative-sequence voltage, a second negative-sequence voltage and a third negative-sequence voltage, predefining setpoints for a negative-sequence current system depending on the calculated, symmetrical negative-sequence voltage system including a first negative-sequence current component, a second negative-sequence current component and a third negative-sequence current component, wherein the setpoints are defined such that a balancing of the measured voltages is achieved, feeding an asymmetrical three-phase AC current into a wind farm network or an electrical supply network depending on the predefined setpoints.

An electrical charging apparatus (10) for charging an electrical energy store of a motor vehicle (12) has an electrical connection (16) to electrically connect the charging apparatus (10) to a charging station (14) and to interchange electrical energy with the charging station (14). An electrical converter (18) is connected to the electrical connection (16) to interchange the electrical energy with the charging station (14) via the electrical connection (16) and to convert the electrical energy. A control unit (20) is connected to the electrical converter (18) to control the interchange of the electrical energy. A communication interface (22) is assigned to the control unit (20) and is designed to interchange data (34) with the charging station (14). The control unit (20) is designed to control the interchange of the electrical energy on the basis of the data.

A method for operating a power generation system coupled to a power grid during a grid unbalance event, a method for determining an injection current to be supplied into a power grid by a power generation system, and a method for addressing an asymmetric grid fault in a power grid connected to a power generation system are provided. The methods may be carried out based on a reactive or an active power/current priority.

A device determines a first current, of a first input phase of a power system, and a second current, of a second input phase of the power system. The device determines whether the first input phase and the second input phase are balanced based on the first current and the second current. When the first input phase and the second input phase are not balanced, the device selects the first input phase and an output phase of the power system. The device balances the first input phase and the second input phase by using the first input phase and the output phase.

A control circuit for converting an unbalanced grid voltage into a DC voltage is provided. The control circuit includes a controller having a voltage detection module, a first transformation module, a level shift module, and a second transformation module. The voltage detection module provides voltage component values indicating the voltage in each phase of a three-phase AC power supply. The first transformation module converts the voltage component values from a stationary reference frame into reference voltage signals in a rotating reference frame using a Clarke-Park transform. The level shift module compensates the reference voltage signals to simulate a balanced three-phase AC voltage. The second transformation module converts the compensated reference voltage signals from the rotating reference frame to the stationary reference frame using an inverse Clarke-Park transform. The controller operates a single stage DAB converter for providing a DC charging voltage to a battery that is substantially free of fluctuations.

A device controls a load flow in an alternating-voltage network. The device is distinguished by a module series circuit of two-pole switching modules that can be inserted in series into a phase line of the alternating-voltage network. Each switching module has an energy store and controllable power semiconductors that can be switched on an off and each switching module can be controlled in such a way that a switching-module voltage can be produced at the poles thereof, which switching-module voltage corresponds to a positive or negative energy-store voltage or a voltage having the value of zero. A control apparatus for controlling the switching modules is provided, which control apparatus is configured to control the switching modules in such a way that a periodic longitudinal voltage can be produced at the module series circuit. A method for controlling a load flow in an alternating-voltage network is performed by the device.

Systems and methods are provided for detecting and compensating for loss of a phase of a three-phase power source, elements of the system including: a sensing unit, which measures current and voltage levels of each phase of the three-phase power source; a switching unit having three primary relays and three backup relays; and a microcontroller, configured to receive measurements from the sensing unit, to determine from the measurements a lost phase and a less-loaded phase of the two remaining phases, and responsively to activate the switching unit to disconnect the lost phase and to connect the less loaded phase to provide backup power in place of the lost phase.

A method for operating an unbalanced load manager for a three-phase induction motor or heater, includes receiving, by a load manager, values representative of current flow sensed by current sensors and voltages sensed by voltage taps corresponding to phases of a three-phase power system providing power to the motor or heater. The method includes detecting, by the load manager, a transition from positive or negative to zero current, to measure a phase shift between line-to-line and current. The method further includes synchronizing, by the load manager, firing from line-to-line signal to line-to-neutral signal of phases of the three-phase power system, using the measured phase shift between line-to-line and current.

A method of determining a configuration of multiple power supply units of a computer system. According to the method, in a first step a time shift between different synchronization signals is evaluated, wherein the different synchronization signals are associated with different power supply units among the multiple power supply units of the computer system. In a subsequent step, a connection configuration of the different power supply units is determined from the evaluated time shift. In this regard, a predetermined first time shift characteristic is associated with a connection configuration of the different power supply units to different power phases of a multiple phase power system, whereas a predetermined second time shift characteristic is associated with a connection configuration of the different power supply units to one shared power phase of the multiple phase power system. With such a method a power management of the computer system may be enhanced.

Provided is a power grid adjustment method based on a load of a variable frequency air conditioner. The method includes: establishing a mathematical simulation model of a virtual synchronous motor in a variable frequency air conditioner controller; establishing a virtual inertia control segment and a droop control segment of power grid adjustment according to the mathematical simulation model; obtaining a reference value of rotation speed variation of a compressor by the virtual inertia control segment; obtaining a reference value .sub.ref of rotational angular frequency of the compressor by the droop control segment; and inputting a sum of the reference value .sub.ref of rotational angular frequency of the compressor and the reference value of rotation speed variation of the compressor into a field-oriented controller (FOC) to control rotation of a motor.