Abstract
This study presents a step toward the grid connection of a wave-energy park through an electric power conversion system (EPCS) developed and installed for the wave-energy harvesting in Lysekil, Sweden. The EPCS comprises a rectifier, a DC bus, and an inverter followed by a harmonic filter (HF). The higher- and lower-order harmonics injected by the inverter in a power quality context are investigated. The lower-order voltage harmonics partially distort the voltage-source inverter output grid current. A phase-locked loop-based (PLL) grid-phase tracking is used to attenuate the lower-order harmonics by reflecting the grid harmonics in the inverter output. An expression for the grid-current harmonics as a function of the grid-voltage harmonics has been derived and implemented. A mathematical model is derived to obtain a transfer function for the PLL, and finally, proportional–integral gains are tuned for stable system operation. An HF for mitigating the higher-order harmonics has been implemented. The total harmonic distortion is evaluated experimentally, and the results fulfil the grid-code requirements at various frequencies and harmonic orders.
Highlights
The global energy demand is rising every decade and is expected to increase up to 25% by 2040 [1]
We presented an experimental validation for the power quality improvement by analysing the harmonics content of the grid voltage and current
The results presented analyse the work, which validate that the higher-order and the lower-order grid-current harmonics are reduced and satisfied the grid-code requirements
Summary
The global energy demand is rising every decade and is expected to increase up to 25% by 2040 [1]. Previsic et al [15] described how to categorise WEC devices They can be categorised according to three popular methods of absorbing the energy: the overtopping device, the oscillating water column, and the oscillating body. The latter can be divided into three sub-categories based on the direction of the radiation force. This paper focuses on the grid integration of RES by mitigating the orders of the harmonics using a PLL grid-phase-tracking method. To convert the energy from the waves into electric energy, the translator is equipped with magnets, which induce a current in the stator windings of the generator as the translator moves in a vertical direction [20, 38]. The research on the design developments – through performance monitoring of the mechanical lead through and its sealing and guiding components – is inherently long term due to the expected lifetime of these components
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
