| 摘要 |
The invention relates to a converter comprising a converter controller (20) for a wind turbine and comprising a chopper (6). The converter controller (20) has a dynamic threshold (Idyn) which is permitted for a first tolerance time (t1) and a static threshold (Istat) of the converter (2). Furthermore, an overcurrent module (8) is provided which comprises a threshold expander (81) that is designed to increase the static threshold (Istat) by a part of the difference between the static threshold and the dynamic threshold (Idyn) as an additional current (Iplus) and which comprises a dynamic module (82) that interacts with the threshold expander (81) such that overcurrents between the static threshold (Istat*) which has been increased by the additional current (Iplus) and the dynamic threshold (Idyn) are conducted to the converter (2) in a first stage and at least partly to the chopper (6) in a second stage, wherein the second stage is activated after a second tolerance time (t2). In this manner, when overcurrents occur, i.e. currents above the static threshold which has been increased by the additional current up to the dynamic threshold, the increased current is applied not just to the converter but also to the chopper paired with said converter. The active components of the converter are thermally discharged in a controlled manner by bypassing into the chopper. Thus, the output capacity of the converter and wind turbines equipped with said converter is increased for the grid products Q and cos f, which are becoming increasingly important. This is achieved without changing components and thus practically without additional costs (using slightly reinforced cables and optionally power chokes). |
