Vestas Wind Systems A/s

Masoud Parkhou

Michael Casem Tumabcao

Lars Helle

Bing Xuan Li

Cem Özgür Gerçek

Xue Wen Luo

Bing Li

According to embodiments described herein a Modular Multilevel Converter (MMC) is pre-charged by: driving a bypass current from an auxiliary power source through a plurality of bypass switches included in a corresponding plurality of cells; in response to a summed voltage across a plurality of cell capacitors included in the plurality of cells satisfying a drive threshold, driving an insert current through a plurality of insert switches included in the plurality of cells; and in response to a voltage across a Direct Current (DC) link capacitor satisfying a pre-charge threshold when driving the insert current, opening a circuit breaker connecting the auxiliary power source with the plurality of cells and connecting a generator with external power line rails between which the DC link capacitor is connected.

Modular multilevel converter pre-charging

A wind turbine fault detection circuit is designed to determine presence of a fault. In a described embodiment, the wind turbine fault detection circuit utilizes a magnetometer in the form of a hall-effect sensor coupled between a power converter and a ground element to measure a ground current from the power converter to obtain a real ground current. The wind turbine fault detection circuit utilizes a comparator to determine presence of a fault based on the real ground current.

Wind turbine fault detection circuit and method

The present invention relates to a dump load applied in a wind turbine generator; normally it is only operating to absorb the energy during faults. Therefore in the majority time of wind turbine generator operation, the dump load is not applied, and its health condition is unknown. This invention is about a method to check the dump load condition during normal operation.

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Hammel, Denmark

Masoud Parkhou