Marine Current Power Generation Research Articles

Maximum power point tracking control and power distribution of marine current power system based on hybrid energy storage

Abstract With the development of industry in modern society leading to the energy crisis and the problem of the earth’s environmental pollution, it is especially important to generate electricity from renewable and clean energy sources. Marine current power generation, as a form of marine energy use, is also the object of widespread concern at home and abroad. A system consisting of supercapacitors and batteries can smooth out the fluctuations of the generating power. Power distribution is a necessary step to achieve smooth grid-connected power fluctuation by using the hybrid energy storage system (HESS). In the article, low-pass filter (LPF) and empirical mode decomposition (EMD) algorithms are used to distribute the marine current power generation, and the simulation experimental model of the present system is constructed in the Matlab/Simulink environment. Results of the simulation experiments show that the power curve of the generator side is obtained, and the generation power distribution is realized. Power signals of different frequencies are separated through the power distribution, so as to obtain the reference power of supercapacitors and the batteries.

Study of the Motion Performance of Marine Current Power Plant Turbine Floaters Due To Ocean Current Forces under Moored Conditions

Indonesia targets carbon emissions to reach 0% in 2060 and is replaced by optimizing the use of renewable energy sources. Indonesia as an archipelago country, with the potential of thousands of straits can be utilized as a source of ocean currents as a source of electrical energy. The electricity generated is obtained from a turbine rotor that rotates due to the force of the ocean current flow. To support the turbine rotor to move in the sea, a floating support structure is needed. In this study, a trimaran tipe support structure is used where on the left and right sides are installed 2 (pieces) turbine rotors @ 50 kW each, so that the total has a capability of 200 kW (@4 x 50 kW). The novelty of this study is the utilization of Trimaran technology in marine current power generation turbines, which has good stability, low resistance, and a wider deck area rather than monohull structures. A numerical study using Computational Fluid Dynamics (CFD) is used to calculate the program. The results showed that the floater only moves backward and then is pulled forward with a small amplitude of movement in the X-direction, while those on the Y and Z axes are insignificant. The turbine floater can be immediately stabilized and the turbine rotor will rotate due to the force of the ocean current received. Therefore, in this study, the marine current turbine using trimaran type is showing good ability to survive in Indonesian waters even in high current areas.

Marine Current Turbine Imbalance Fault Detection Method Based on Angular Resampling

Marine current power generation is increasingly attracting worldwide attention. However, mechanical imbalance fault often occurring when MCT blades are biofouled or corroded. This is a challenging problem due to the varying shaft rotating frequency (SRF) generate by the variable current flow. To deal with the imbalance fault, an angular resampling method based on the instantaneous power signal is proposed. This method monitors the output power of a variable-speed MCT generator and first processes the data using an angular resampling algorithm is to obtain a stationary signal. In the second step, a low-pass filter removes high frequencies and extract the fault characteristic. The simulation and the experiments verify the effectiveness of the proposed method for the MCT imbalance faults. The comparison with the motor current or voltage signature analysis has shown its superiority in terms of sensitivity to fault severity.

Adaptive backstepping control for maximizing marine current power generation based on uncertainty and disturbance estimation

The renewable energy from marine currents is highly promising as a clean, reliable and predictable energy source for the next-generation electricity generation. Therefore, the paper focuses on the design and implementation of the high-efficiency control for maximizing the marine current power generation and hence an adaptive backstepping controller with uncertainty and disturbance estimation is proposed for a generic horizontal marine turbine. The turbine design principle and dynamics modelling are presented and then the control problem is formulated. Consequently, the controller is designed to be composed of a marine turbine speed control loop and a q-axis current control loop while the uncertainty and disturbance is estimated and compensated. A swell filter is also incorporated into the control loop to smooth generator power fluctuations. The stability of the proposed control is verified via the Lyapunov synthesis and all the tracking errors are guaranteed to converge to zero asymptotically. The proposed control is verified and the test results indicate that the generator produces obviously more power (up to 30% more power) when using the proposed control in comparison with a conventional backstepping control.

Modeling of a hybrid marine current-hydrogen active power generation system

This paper presents the modeling and the simulation of a hybrid marine current-hydrogen power generation system. The marine current power generation system consists of a fixed pitch marine current turbine directly coupled to a permanent magnet synchronous generator (PMSG). The generator is connected to a DC link capacitor via a controlled rectifier, which has two modes of operation. The first mode is the maximum power point tracking (MPPT) by using torque control when the generator runs below the rated speed. The second mode is the power limitation (at the rated value) when the generator runs above the nominal speed. The generated power is transferred from the DC-link to the load via an inverter to run the system in a stand-alone operation mode. An energy storage system must cover the difference between the generation and the consumption for this scheme. The hydrogen, compared with the different energy storage systems, exhibits characteristics more applicable for marine current power generation systems. When the generated power is higher than the load requirements, a Megawatt-scale proton exchange membrane (PEM) electrolyzer consumes the surplus energy for hydrogen generation. The generated hydrogen is stored in tanks to feed a PEM fuel cell system to generate power in case of shortage. Based on this topology and operation procedure, the overall system is called an active power generation system. The MW scale PEM electrolyzer model is presented based on state of the art and the literature of different scales PEM electrolyzer system modeling.

The treatment of moving problem for constant-frequency double-rotor generator in finite element analysis

The constant-frequency double-rotor generator has the potential to be used in the marine energy conversions, such as tides and marine current power generation system due to the advantages. However, there are two different rotational speed movement boundaries in the constant-frequency double-rotor generator, especially the inner moving part boundary between the inner wound rotor and outer permanent magnet rotor. This complicates the finite element analysis and greatly increases the analysis time. In this article, a new finite element analysis method based on double boundaries interpolation multiple reference frame is proposed. The principle of the interpolation multiple reference frame method is introduced, and the analysis and comparison with the traditional method are carried out. The analysis results show that the interpolation multiple reference frame method simplifies the preprocessing procedure, reduces computation time, ensures high calculation accuracy, and has the potential to be applied in all kinds of multiple mechanical port machines.

Implementation and Measurements of a Prototype Marine-Current Power Generation System on Peng-Hu Island

This paper presents the design, implementation, and field measurements of a prototype marine-current power generation system (MCPGS) for capturing energy from marine current. The studied prototype MCPGS employs the flowing marine-current energy near the Cross-Sea Bridge, Peng-Hu Island, Taiwan. The design of the prototype MCPGS has to meet the practical marine-current flowing conditions and the severe environmental conditions in the ocean of Peng-Hu Island. The designed MCPGS unit consists of a three-blade marine-current turbine, a gearbox, a three-phase permanent-magnet generator, and a power converter that is used for converting generated energy to be stored in the battery. Field measured results for the studied MCPGS under different practical marine-current speeds in Peng-Hu Island are performed and analyzed.

Design and Evaluation of a Tidal In-Stream Generator Power Port

Oceanic currents and tidal streams are a predictable and vast source of energy. The astronomical nature of the underlying forces causing such streams, results in speed variations that change at certain time intervals. There are different methods for harnessing part of this vast and renewable source of energy; however, regardless of the method used, integrating a large-scale tidal in-stream energy converter into a conventional power system poses many challenges, in particular, in weaker networks. Injection of the captured stream power to a nonstiff network changes the magnitude of the voltage at different times of the day. The impact on the voltage magnitude is commonly most critical if tidal generators and consumers share the same medium voltage feeder, which is a case that seems inevitable especially when considering the electrically remote but energy-rich areas of estuaries, oceanfronts, and natural water channels. This investigation provides designing details of a hybrid power port solution that establishes an independent active and reactive power control, enabling it to regulate the point of common coupling voltage, while transferring variable amounts of captured stream power to a nonstiff grid. To verify the feasibility of the proposed scheme, an example system is designed and tested using a common tidal stream power profile. This investigation is a timely contribution to the emerging field of marine current power generation.

Research on Low Power Marine Current Power Generation System

This study proposes a simple topological structure and power control method for a small scale stand alone marine current system, in which a diode rectifier, DC/DC boost converter for the maximum power control, battery as a storage element and a single phase inverter to link with load. The study establishes the steady-state mathematical model of marine current power generation system and derives the formula between the maximum power point and dc battery voltage. Then use the measurements of DC voltage and DC current to obtain Maximum Power Point Tracking (MPPT) by controlling the duty cycle of the boost converter switch in order to simplify the system structure and the control strategies. In this case, the hill climbing searching algorithm is employed to get maximum power point and the double closed loops control strategy is used to improve the dynamic and static performance of single phase inverter. The simulation model is developed in MATLAB/Simulink. And the control method is executed in dSPACE1104 real-time platform. The simulation and experimental results demonstrate the feasibility and validity of the proposed control strategies.

Marine-current power generation model for smart grids

This short communication introduces the first marine-current power generation model to be integrated into power flow studies of smart grids. The stochastic aspect of marine-current velocity affecting the real power output of marine-current generators is provided by a closed formula. Also, a new closed formula for power coefficient of marine-current generators versus marine-current velocities is set up. The introduced marine-current power generation model is validated on real measurements obtained in the sub-sea areas of Alderney Race (Channel Islands) in UK and Gun-barrel passage in Fiji.

A Comparison of Rotational Speed of Marine Current Power-Generation Turbine with and without a Speeding-up Inlet

This paper experimentally investigates effects of speeding-up inlet on rotational speed of marine current energy turbine. Several length-radius ratios L/d and area ratios A´/A of the speeding-up inlet as well as several flow yawing angles θ were considered. Also, a comparison of rotational speed of turbine in the presence and absence of speeding-up inlet was made. A relation between flow velocity V and rotational speed of the inlet n was analyzed. And a relation between flow velocity and rotational speed of turbine in free stream was theoretically developed.

Dynamic Analysis of a Grid-Connected Marine-Current Power Generation System Connected to a Distribution System

This paper presents dynamic-performance enhancement of a grid-connected marine-current power-generation system consisting of an induction generator (IG) driven by a marine-current turbine (MCT) through a gearbox. The studied 1.5-MW MCT-IG set is connected to an onshore 23-kV distribution system through an undersea cable, two onshore back-to-back power-electronics converters (PECs), and an onshore step-up transformer. The mathematical models of the studied marine-current power-generation system including marine-current speed, three-blade mechanical system, gearbox, IG, PECs, undersea cable, step-up transformer, etc. are established and combined together. The DC-link voltage between the two PECs and the generated active power of the IG are controlled by the PECs using the designed fuzzy logic controller (FLC). Time-domain simulations based on the developed nonlinear model of the studied marine-current power-generation system subject to various torque-disturbance conditions are performed. It can be concluded from the simulated results that the generated power of the studied marine-current power generation system can be effectively controlled to deliver to the grid by the proposed control scheme under the selected operating conditions.

Marine-current power generation by diffuser-augmented floating hydro-turbines

The oceans represent a huge energy reservoir consistent of stored solar and gravitational energy in several forms, causing ceaseless movements of an enormous volume of water. This energy is generally diffuse but, in many cases, significantly more concentrated than other forms of renewable energy already being successfully exploited on land. Among the ocean-energy resources, wave and marine-current energy emerge as the most promising options for massive ocean-energy generation in the immediate future. The main objective of this paper is to focus on trends that can lead to a feasible massive marine-current-power future scenario, and to introduce a technological solution which could help to reach that goal. We shall describe the main features of a floating marine-current-power system that introduces conceptual innovations in order to improve the technical and economical performance.