Electrically coupling a first electrical supply network to a second electrical supply network

An energy converter for electrically coupling a first electrical supply network to a second electrical supply network, said energy converter comprising:

• a switch element;
• and
• a control unit electrically coupled to the switch element and configured to operate the switch element in a switching operation such that the energy converter provides a predefinable energy conversion functionality, said control unit configured to set a supply-network current for one of the first and second electrical supply networks in dependence on a comparison of the supply-network current with a predefinable comparison current, said control unit configured
• to provide a first operating mode for the switching operation for setting an electrical voltage at the one of the first and second supply networks using a PWM method in dependence on the comparison,
• to provide a second operating mode for the switching operation in which the switch element is switched when, during the comparison, a difference between the supply-network current and the predefinable comparison current is greater than a first predefinable relative switching value and/or smaller than a second predefinable relative switching value, and
• during operation of the energy converter, to change between the first operating mode and the second operating mode such that in the event of a supply-network disturbance, a change is effected from the first operating mode to the second operating mode and, when the supply-network disturbance has been overcome, a change is effected back from the second operating mode into the first operating mode.

An energy converter system for electrically coupling a first electrical supply network to a second electrical supply network, said energy converter system comprising at least two energy converters connectable to the first electrical supply network and to the second electrical supply network, each said energy converter comprising a switch element, and a control unit electrically coupled to the switch element and configured to operate the switch element in a switching operation such that the energy converter provides a predefinable energy conversion functionality, said control unit configured to set a supply-network current for one of the first and second electrical supply networks in dependence on a comparison of the supply-network current with a predefinable comparison current, said control unit configured

• to provide a first operating mode for the switching operation for setting an electrical voltage at the one of the first and second supply networks using a PWM method in dependence on the comparison,
• to provide a second operating mode for the switching operation in which the switch element is switched when, during the comparison, a difference between the supply-network current and the predefinable comparison current is greater than a first predefinable relative switching value and/or smaller than a second predefinable relative switching value, and
• during operation of the energy converter, to change between the first operating mode and the second operating mode such that on the occurrence of a supply-network disturbance, a change is effected from the first operating mode to the second operating mode and, when the supply-network disturbance has been overcome, a change is effected back from the second operating mode into the first operating mode.

A method for operating an energy converter, which electrically couples a first electrical supply network to a second electrical supply network by converting electrical energy via a switch element, said method comprising:

• operating the switch element in a switching operation such that the energy converter provides a predefined energy conversion functionality;
• and
• setting a supply-network current for one of the first and second supply networks in dependence on a comparison of the supply-network current with a predefined comparison current,
• wherein a first operating mode for the switching operation is provided in which an electrical voltage is set on the one of the first and second supply networks using a PWM method in dependence on the comparison,
• wherein a second operating mode is provided in which the switch element is switched when, during the comparison, a difference between the supply-network current and the predefined comparison current is greater than a first predefined relative switching value and/or smaller than a second predefined relative switching value, and
• wherein during operation as intended of the energy converter, there is a change between the first operating mode and the second operating mode such that, on the occurrence of a supply-network disturbance, a change is effected from the first operating mode to the second operating mode and, when the supply-network disturbance has been overcome, a change is effected back from the second operating mode into the first operating mode.