Experimental demonstration of performance of a vertical axis marine current turbine in a river

Abstract

An experimental station for marine current power has been installed in a river. The station comprises a vertical axis turbine with a direct-driven permanent magnet synchronous generator. In measurements of steady-state operation in varying flow conditions, performance comparable to that of turbines designed for significantly higher flow speeds is achieved, demonstrating the viability of electricity generation in low speed (below 1.5 m/s) marine currents.

Validation of a Coupled Electrical and Hydrodynamic Simulation Model for a Vertical Axis Marine Current Energy Converter

“…C P is a function of the tip speed ratio (TSR or λ), i.e., the ratio of blade tip speed to undisturbed water speed, λ = ωr v , where ω is the angular speed of the turbine in rad/s and r the turbine radius in meters. The C P (λ)-curve for the turbine has been experimentally verified in [15] to have a maximum power coefficient at tip speed ratio 3.1 for a power coefficient of 0.26. The turbine parameters can be found in Table 1.…”

“…Experimental data at a range of water speeds and resistive AC-loads are in [15] used to investigate the performance of the turbine. In the study, the power produced by the turbine is estimated using the rotational speed of the turbine and by assuming that the power from the iron losses and mechanical losses in the generator are 180*ω plus the electrical power dissipated in the load.…”

“…The power capture curve of the turbine for water speeds 1.1 m/s to 1.5 m/s and AC loads from 1 Ω to 9 Ω at steps of 1 Ω has been simulated. The simulation has been plotted together with the experimentally obtained fitted curve presented in [15] in Figure 7a. The experimentally measured efficiency of the total system, including all losses in the turbine and generator, is plotted in Figure 7b.…”

Marine Current Energy Converters to Power a Reverse Osmosis Desalination Plant

“…The Uppsala marine current energy converter can produce power in water speeds ranging from about 1 m/s up to almost 2 m/s. The power coefficient curve of the turbine has been experimentally derived in [20] to have a peak efficiency of 0.26 when run at optimal tip-speed-ratio (TSR), i.e., the ratio between water speed and speed of the blades. If the water speed is lower than 1.0 m/s, the turbine cannot produce a net positive hydrodynamic torque, and if the water speed is higher than 2 m/s, the loads on the struts and blades may be too high, for the specific design.…”

Identification and Control of a River-Current-Turbine Generator—Application to a Full-Scale Prototype

“…Water-turbine-based generation systems installed in rivers, generally named as microhydro power plants, use various resource capturing devices depending on each particular application. For instance, microhydro power plants use some classical designs such as (semi) Kaplan or Francis water turbines, but the marine-current or river-flow generation systems uses more modern designs such as axial-flow [7], [8], vertical-axis [9], [10] or cross-flow water turbines (CFWT) [11], [12]. Their particular set-up -free-water-flow conditions -invariantly requires the use of modern electrical generator control techniques such as vector control, variable-speed control, maximum power point tracking (MPPT) [2], [8], [13], which may generally be found in renewable power generation technology.…”