Short time power smoothing of a low power wave energy system

This paper presents smoothing of oscillatory power generated by a wave energy converter (WEC) from sea wave. WEC oscillates in sea wave and an electrical generator connected to it generates oscillatory power of typical period of oscillation of 6 to 10 seconds. This power can not be directly fed to a load or grid and hence an energy storage device is required to filter out the oscillation. Super-capacitor (SC) is a better choice over battery as an energy storage device due to its low maintenance requirement and better power capacity. A WEC is emulated in hardware using induction motor (IM) and a permanent magnet synchronous machine (PMSM) is used as the generator. Power generation from WEC is controlled by controlling PMSM current. Power flow to and from SC is controlled to smooth the power output. The overall control system is implemented in hardware and smoothing of the oscillatory power using SC is demonstrated.