A power conversion circuit has a controller with an input terminal and a circuit configured to drive an electric current out of the input terminal in response to a condition of the controller. An indicator is coupled to the input terminal of the controller. The controller includes a clock signal controlling the electric current out of the input terminal. The input terminal is a voltage sensing terminal or feedback input terminal in some embodiments.

The invention relates to a weed inactivation device, comprising at least one electrode, whereby at least one electrode is directed to the weed. The electrode is supplied with electrical energy by an electrical power supply, containing an h-bridge inverter for DC/AC conversion to create rectangular wave AC-current. The inversion takes place at frequencies above 1.0 kHz. The weed activation device enables weed control without utilization of poisonous herbicides.

The invention relates to a weed inactivation device, comprising at least one electrode, whereby at least one electrode is directed to the weed. The electrode is supplied with electrical energy by an electrical power supply, containing an h-bridge inverter for DC/AC conversion to create rectangular wave AC-current. The inversion takes place at frequencies above 1.0 kHz. The weed activation device enables weed control without utilization of poisonous herbicides.

Systems (100), power modules (108), and methods for using in controlling a converter (110) coupled between a power generator (104) and an electric grid (102). A power module (108) includes the converter (110) configured to supply the output from the power generator (104) to the electric grid (102) and a controller (112) coupled to the converter (110) and configured to disable the converter (110) in response to a grid fault event, to identify the type or the grid fault event after a first predetermined interval from disabling the converter (110), and to enable switching of the converter (110), when the type of the grid fault event is identified as a low voltage condition.

Systems (100), power modules (108), and methods for using in controlling a converter (110) coupled between a power generator (104) and an electric grid (102). A power module (108) includes the converter (110) configured to supply the output from the power generator (104) to the electric grid (102) and a controller (112) coupled to the converter (110) and configured to disable the converter (110) in response to a grid fault event, to identify the type or the grid fault event after a first predetermined interval from disabling the converter (110), and to enable switching of the converter (110), when the type of the grid fault event is identified as a low voltage condition.

An exemplary power conversion system includes a power conversion device and a control system. The power conversion device converts electrical power from one form to another. The power conversion device includes at least one switching element capable of being turned off to block an electrical current flowing through the at least one switching element. The control system is electrically coupled to the power conversion device for monitoring an electrical current flowing through the at least one switching element and for monitoring at least one parameter in association with the operation of the power conversion system. The control system further generates an over-current threshold value that is variable with respect to at least one monitored parameter.

In order to protect reverse currents, several strings of a photovoltaic generator, which are connected in small groups respectively via a DC/DC-converter, parallel to a common DC voltage intermediate circuit, the current which flows over each of the DC/DC-converter is detected and if a reverse current is detected flowing through one of the DC/DC converters, the converter is stopped by controlling the DC/DC-converter.

In order to protect reverse currents, several strings of a photovoltaic generator, which are connected in small groups respectively via a DC/DC-converter, parallel to a common DC voltage intermediate circuit, the current which flows over each of the DC/DC-converter is detected and if a reverse current is detected flowing through one of the DC/DC converters, the converter is stopped by controlling the DC/DC-converter.

A varistor failure detector includes one or more surge detector in communication with a varistor, to detect surges shunted by the varistor and a processor, in communication with the at surge detector(s). The processor is programmed to count surges shunted by the varistor, as indicated by the surge detector (s) and store at least one count representing a cumulative count of surges shunted by the varistor. An indicator of the count may be provided to an operator to indicate that the varistor should be replaced, to avoid catastrophic failure of the varistor.

A varistor failure detector includes one or more surge detector in communication with a varistor, to detect surges shunted by the varistor and a processor, in communication with the at surge detector(s). The processor is programmed to count surges shunted by the varistor, as indicated by the surge detector (s) and store at least one count representing a cumulative count of surges shunted by the varistor. An indicator of the count may be provided to an operator to indicate that the varistor should be replaced, to avoid catastrophic failure of the varistor.