A redundant and fail-safe blade
system of a wind
turbine includes at least one
blade pitch drive (20, 21, 22) and at least two
power control modules (60, 61, 62, 6′) for controlling the
blade pitch drive (20, 21, 22). The
power control modules (60, 61, 62, 6′) are connected to the
blade pitch drive (20, 21, 22) by a switching unit (10) which allows an alternative connection between the blade
pitch drive (20, 21, 22) and any of the
power control modules (60, 61, 62, 6′). In operation, the blade
pitch drive (20, 21, 22) is controlled by only one of the power control modules (60, 61, 62, 6′). If a malfunction of the currently operating power control module (60, 61, 62, 6′) is detected, switching unit (10) provides a connection to the other power control module (60, 61, 62, 6′) to allow an ongoing operation of the wind
turbine without an unplanned or forced shut-down.