Proposed circuit design could increase switching efficiency in wind energy grids
Proposed circuit design could increase switching efficiency in wind energy grids lead image
Wind farms can struggle to maintain a steady power supply when wind levels fluctuate. To overcome this, grids rely on super magnetic energy storage system (SMES) to manage load frequency and voltage instability. Author Kenneth Okedu proposes improvements to SMES by integrating dual parallel DC-DC chopper switching circuitry. Simulations of the proposed scheme show the new circuitry design outperforms current SMES during grid disturbance under the same wind speed.
Like flywheels or capacitors, SMES are useful for short-term energy storage during wind fluctuations. SMES store the energy, which comes from the continuous flow of current in a superconducting coil, as a magnetic field which remains after voltage across the system has been removed. The energy storage depends on average power and discharging time, and SMES require short discharging time, relative to capacitors or flywheels, to protect the voltage source converter during grid disturbance. The proposed dual parallel DC-DC chopper addresses this issue, improving the switching efficiency.
Integrating a dual parallel DC-DC chopper in the SMES helps increase the circulating current in the voltage source converter circuitry and increases switching efficiency. The author notes that improving switching efficiency moves mixed generation wind energy closer to maintaining near zero steady state error as a power system.
The proposed design could readily be integrated into existing wind farms. This proposed control strategy makes use of the conventional fixed speed squirrel cage induction generators in modern wind farms, instead of phasing them out. Okedu is now looking to collaborate with wind farm developers and policymakers to implement this research.
Source: “Improving the dynamic performance of grid connected wind farm using new SMES switching technique,” by Kenneth E. Okedu, Journal of Sustainable and Renewable Energy (2018). The article can be accessed at https://doi.org/10.1063/1.5040244 .
