Sma Solar Technology Ag

Christian Hardt

Andreas Falk

Neidhardt Bechtel

Vitali Sakschewski

Stijn Stevens

Dirk Hermeling

Michael Strnad

Christian Halt

Christoph Jordaan

A method for operating an electrolysis device, having a converter which is connected on an AC voltage side to an AC voltage grid via a decoupling inductance and draws an AC active power from the AC voltage grid, and an electrolyzer, which is connected to the converter on the DC voltage side, is provided. The method includes operating the electrolysis device, when a grid frequency corresponds to a nominal frequency of the ACT voltage grid and is substantially constant over a time period, with an electrical power which is between 50% and 100% of a nominal power of the electrolyzer, and operating the converter in a voltage-impressing manner, such that an AC active power drawn from the AC voltage grid is changed on the basis of a change and/or a rate of change of the grid frequency in the AC voltage grid.

Electrolysis device having a converter and method for providing instantaneous reserve power for an AC voltage grid

The disclosure describes a method for operating an energy supply installation which is connected to an AC supply grid via a transformer, and exchanges electrical power with the AC supply grid via the transformer. The transformer is connected on a first side to the AC supply grid and on a second side to an AC installation grid of the energy supply installation, wherein the energy supply installation has at least one inverter which exchanges electrical power between a DC unit on the DC side of the inverter and the AC installation grid on the AC side of the inverter. The method includes receiving at least one parameter of the power conversion of the at least one inverter by an installation controller, determining a setpoint AC voltage for the AC installation grid by the installation controller according to the parameter, transmitting the setpoint AC voltage to the transformer.

Method for operating an energy supply system, system controller for an energy supply system, and energy supply system

A method for operating an island system is disclosed. The island system includes a group of voltage-controlling converters, wherein each of the voltage-controlling converters of the group are configured to convert power of respectively connected regenerative power sources into AC power in accordance with a respective frequency-power characteristic curve. The island system also includes a load having a power consumption that depends on a voltage amplitude of an AC voltage of the island system, and a control unit that is configured to transmit a default value of the voltage amplitude to the group of voltage-controlling converters. The method adapts the power to be consumed by the load.

Method for operating an island system, and island system

A method for operating an inverter which is connected to an energy supply grid via a transformer for feeding in electrical energy into the energy supply grid, includes measuring output currents and output voltages of the inverter, and actuating power switches of the inverter using actuation signals that are generated as a function of the measured output currents and the measured output voltages at a fundamental frequency of the energy supply grid. The actuation signals are further generated as a function of a harmonic component of the measured output voltages of the inverter at a multiple of the fundamental frequency using a control loop with positive feedback.

Inverter and operating method for an inverter

An inverter and a method for detecting a phase failure in an energy supply grid during operation of an inverter, which is connected to the energy supply grid for feeding electrical energy via a YNd transformer is disclosed. The method includes transforming the values of the output currents into a symmetrical positive-sequence current value and into a symmetrical negative-sequence current value of a coordinate system rotating at a fundamental frequency of the energy supply grid. The method further includes determining a ratio of the negative-sequence current value to the positive-sequence current value, and signalling a phase failure in the energy supply grid if the determined ratio is greater than a preset threshold value for longer than a preset time period. The disclosure furthermore relates to an inverter designed for implementing the method.

Inverter and method for detecting a phase failure in an energy supply grid

The subject matter of the invention is a method for detecting an isolated network for an inverter () carrying a converter voltage that is adapted for connection in parallel with a grid () having a mains frequency and electric loads and that is decoupled from the grid () by a choke (), a test signal being superimposed upon the converter voltage at a test frequency the frequency of which is smaller than the mains frequency, the amplitude of the test signal being much smaller than the nominal voltage amplitude of the mains voltage on the one side but still just large enough on the other side for changes in reactive power to be detectable as a result of the test signal, a reactive power share being determined, which oscillates with the test frequency, this share not being allowed to fall below an imposed minimum for an isolated operation to be reliably excluded.

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Kassel, Germany

Christian Hardt