A wind turbine power controller and wind turbine system

A power controller (130abc) for controlling an amount of electric output power forwarded from a wind turbine generator (121a) to an alternating current network, which power controller (130a) comprises:

• a rectifier unit (210) configured to receive alternating electric current (ACw) from the wind turbine generator (121a) and based thereon provide basic electric energy in the form of a base direct-current voltage (DC), characterized in that the power controller (130a) comprises a direct-current output interface (280) configured to:
• deliver an output direct-current voltage (DC+) based on the base direct-current voltage (DC), and
• be connected in series with the direct-current output inter-face (280) of at least one additional power controller (130b, 130c) to an input interface (141) of an inverter unit (140) arranged to produce output alternating power (ACG) to the alternating current network based on the output direct-current voltages (DC+) from said in-series connected direct-current output interfaces (280).