Experimental results on a variable-speed small hydro power station feeding isolated loads or connected to power grid

Following a series of articles presenting the modelling and simulation of an autonomous variable- speed hydropower station feeding an isolated load or connected to a power grid ([2], [3]), this paper is aiming to validate on the test bench the solutions proposed earlier. The studied system is composed of a doubly-fed induction generator (DFIG) linked mechanically and electrically (through back-to-back power electronic converters in the rotor circuit) to a permanent-magnet synchronous machine (PMSM) which may recover or supply the slip power. One of the advantages related to this system is that the PMSM and the power converters are designed for only about 25% of the plant nominal power.