Series‐connected multi‐half‐bridge modules converter for integrating multi‐megawatt wind multi‐phase permanent magnet synchronous generator with dc grid

In this study, a new transformerless wind energy conversion system to integrate high‐power multi‐phase permanent magnet wind generators to medium‐voltage local grids is presented. The proposed converter topology consists of multi‐half‐bridge modules with a high ac–direct current (dc) boosting capability. Each phase of an open winding multi‐phase generator is connected to the ac side of a half‐bridge module, whereas the dc sides of the half‐bridge modules are connected in series forming the high‐voltage dc‐link output. The proposed architecture facilitates the employment of semiconductor switches with a relatively low‐voltage rating, which equals the dc‐link voltage divided by the number of generator phases. A detailed analysis of the proposed architecture along with the required closed‐loop control is presented. The proposed architecture is simulated under different operating conditions using a typical 2 MW system, while the experimental validation is carried out using a low‐scale prototype converter.