Energy Power Generation Devices Research Articles

Test and Analysis of the Heat Exchanger for Small Ocean Thermal Energy Power Generation Devices

The application of ocean thermal energy conversion is an effective method to extend underwater vehicles’ running times and operating ranges, and the solid–liquid phase transition of the phase change material (PCM) in the heat exchanger is a key process for underwater vehicles to collect ocean thermal energy. This study proposes a heat exchanger structure for a small-size thermal energy power generation device and establishes the heat transfer model for the heat exchanger. Simulations were conducted considering convective heat transfer, and the obtained results demonstrated the feasibility of the designed structure. A prototype of the heat exchanger was developed, and physical experiments were conducted to validate the performance of the prototype. The results show that the melting process of the heat exchanger can be completed within 6 to 12 h, the solidification process can be completed within 3 to 7 h, and the heat transfer time decreases with the increase in temperature difference, verifying the compatibility with the underwater vehicles’ working patterns. Moreover, the heat exchanger could theoretically extend their lifetime. The results can provide a reference for the structural design and optimization of the heat exchanger for small ocean thermal energy power generation devices in the future.

Influence of circuit on power generation performance of wave energy power generation device using oscillating water column technology

In order to study the influence of the load circuit on the system efficiency and power oscillation of the oscillating water column device, a unified modeling model of the oscillating water column device is built for simulation. According to the coupling relationship in various fields of the oscillating water column device, the differential equation of motion of the turbine generator set is established. The power plant components and systems are modeled by Modelica language. Based on this system, the system-level simulation is carried out and the load circuit is optimized. In addition, experimental tests of the traditional load circuit and the modified load circuit are carried out. Results indicate that the modified load circuit can increase the speed of the turbine to better follow the airflow and balance the system damping, thereby improving the system efficiency. Increasing resistance can reduce the fluctuation of output electric power. Different battery, resistance and generator parameters can cause differences in system efficiency. The research results provide a reference to improve the performance of oscillating water column device.

Experimental Study on the Efficiency of Dynamic Marine Thermal Energy Generator Based on Phase Change Compensation

Miniaturized detection devices in the ocean generally experience problems such as short endurance and unreliable power supplies. This article aimed to develop a dynamic ocean temperature difference energy collection device to capture ocean temperature difference energy and provide objective electricity for stable detection devices. The main focus was to conduct experimental research on the effectiveness of a dynamic ocean temperature difference energy power generation device. During the research process, the fact that ammonia gas in a working fluid is easy to liquefy and vaporize was utilized. By utilizing the increase in seawater temperature during the floating process of the device, it vaporized and drove the turbine to rotate for power generation. In the structural design, multiple sets of small air chambers were creatively proposed, which could effectively control the air pressure and improve the stability of the airflow. By charging the airflow to impact the turbine, multiple sets of power generation fans were used to form a stable current. Further, the buoyancy of the device could be changed by adding phase change materials between the air chamber and the device shell, and the temperature difference between the two ends of the phase change materials could be used to change the electron density of the material to form a weak current. In this experimental study, concepts such as the structural design of multiple small gas chambers, miniaturization of energy collection devices, compensation power generation of phase change materials, and application scenarios of devices combined with Argo buoys were all proposed for the first time. The results of this experimental study indicate that the overall power generation of the device is about 2A, and its maximum output power amplitude is about 22 W. The cyclic thermal efficiency of the power generation device can be increased from +0.19% to +0.88%. The development of this thermoelectric power generation device can provide a considerable stable power supply for ocean observation devices, especially the buoy device represented by Argo, which can extend the endurance of deep-sea exploration devices.

Research on dynamic temporal and spatial distribution characteristics of electrical power system voltage based on random forest algorithm

AbstractThe theme of this study is to find a method that can more accurately classify the spatiotemporal distribution characteristics of power system voltage dynamics. As more and more new energy power generation devices are added to the power network, the accuracy of traditional methods for classifying the spatiotemporal distribution characteristics of power system voltage dynamics has gradually decreased. It is significant to reduce the power loss caused by error in identifying voltage dynamic spatiotemporal distribution characteristics. Hence it is necessary to design methods that can more accurately classify power system voltage dynamic spatiotemporal distribution characteristics data. This study proposes a method for studying the spatiotemporal distribution characteristics of power system voltage dynamics based on an improved random forest algorithm. The information entropy calculation method of decision tree in random forest algorithm is improved. According to the experimental results, the classification accuracy of the method for voltage dynamic spatiotemporal distribution characteristics is 99.55%. It can effectively achieve the dynamic spatiotemporal distribution of power system voltage.

Study on Preparation and Properties of La0.6Sr0.4Co0.2Fe0.8O3-Δ-mGd0.2Ce0.8O2 (M=0,30,40 and 50) Composite Cathode

Solid Oxide Fuel Cells (SOFCs) can convert chemical energy into electrical energy, with high energy conversion rate, safe operation, no pollutant emissions, and is one of the most potential new energy power generation devices in the future. However, at low and medium temperature (below 800℃), the cathode impedance of SOFCs will increase sharply, resulting in adverse effects on cell performance. Finding cathode materials that can work at low and medium temperature is the key to realize large-scale commercial application of SOFCs. LSCF cathode material is one of the commonly used cathode materials for solid oxide fuel cells because of its excellent electronic and ionic conductivity. However, its cathode performance cannot meet the requirements of commercial applications. At high temperature, solid-state reactions are easy to occur between LSCF and commonly used electrolyte materials such as YSZ, SSZ and LSGM, resulting in the formation of an intermediate phase that is not conducive to Oxygen Reduction Reaction (ORR). In this paper, LSCF and Gd0.2Ce0.8O2 (GDC) were combined by ball milling to prepare composite cathode. XRD test found that the two powders mixed at high temperature did not produce new substances, with good chemical compatibility. The electrical conductivity test showed that the electrical conductivity of the composite LSCF decreased significantly from 227 Sꞏcm-2 at 650℃ to 115, 90 and 77 Sꞏcm-2 at 550℃, respectively. The composite cathode with a composite ratio of 6:4 has the lowest polarization impedance, only 0.10 Ωꞏcm2 at 800℃. The discharge test shows that the cathode with the mass ratio of 6:4 LSCF to GDC has the best performance, and the power density is 328 and 256 mW/cm2 at 800 and 750℃, respectively. The performance of the cathode has good stability after working for 50h.

Improvement of Stability in an Oscillating Water Column Wave Energy Using an Adaptive Intelligent Controller

Presently, among the global ocean energy technologies, the most conventional one is the wave energy power generation device based on the oscillating water column (OWC) wave energy converter. Given the fluctuation and randomness of waves and the complexity of the current power grid, the dynamic response of grid connections must be considered. Furthermore, considering the characteristics of the wave energy converter, this paper proposed an adaptive intelligent controller (AIC) for the permanent magnet synchronous generator (PMSG) in an OWC. The proposed controller includes a grey predictor, a recurrent wavelet-based Elman neural network (RWENN), and an adaptive critical network (ACN) to improve the stability of OWC power generation. This scheme can increase the maximum power output and improve dynamic performance when a transient occurs under the operating conditions of random wave changes. The proposed AIC for the PMSG based on OWC has a faster response speed, a smaller overshoot, and better stability than the traditional PI controller. This further verifies the availability of the proposed control strategy.

Experimental study on heave performance of a new wave energy power generation device based on regular waves

As an important form of ocean energy, wave energy is gradually being developed and utilized by coastal countries around the world. Researchers have developed various forms of wave energy conversion devices. In this paper, a new type of horizontal rotor wave energy power generation device is designed and manufactured. The device is in a moored floating state when working at sea. The heave belongs to the vertical movement up and down, which directly affects the stability of the device. Based on the engineering prototype making model and conducting regular wave experiments, four test conditions with the same period and different wave heights were designed to verify the influence of wave height changes on heave plates of different shapes and different installation distances on the stability of the device. Determining the shape of the heave plate and the optimal installation distance under the test conditions provides a theoretical basis for the manufacture of engineering prototypes and sea trials.

Influence of Circuit on Power Generation Performance of Wave Energy Power Generation Device Using Oscillating Water Column Technology

Influence of Circuit on Power Generation Performance of Wave Energy Power Generation Device Using Oscillating Water Column Technology

Design and research of hydraulic conversion system of wave energy generating device

Taking the hydraulic conversion system of the oscillating flapping-wing wave energy power generation device as the research object, a hydraulic conversion system is designed to convert wave energy into usable mechanical energy. Based on the principle of high-efficiency collection of wave energy and stable output of the hydraulic conversion system, the composition of the hydraulic conversion system and the parameters of each component are determined. According to different sea conditions, the pre-charge pressure of the accumulator is adjusted to keep the pressure of the high and low pipelines of the hydraulic system stable, and the mechanical energy is stably output through the hydraulic motor. The AMESim simulation platform is used to build the model of acquisition mechanism and hydraulic conversion system, simulate the motion response of acquisition mechanism under actual sea conditions as the system input, and analyze the effectiveness and output stability of hydraulic conversion system. The results verify that the designed hydraulic conversion system can achieve efficient collection of wave energy. The research results have laid a theoretical foundation for the development and research of wave energy power generation devices.

Research on the dynamic characteristics of the acquisition mechanism of the oscillating flapping wing wave energy power generation device based on the bond graph

Taking the acquisition mechanism of the oscillating flapping-wing wave energy power generation device as the research object, the design of the acquisition mechanism, the bond graph model of the acquisition mechanism and the dynamic characteristics are studied. According to the working principle of the acquisition mechanism of the oscillating flapping wing wave energy power generation device, the bond graph model and the state space equation of the acquisition mechanism are established. Based on the bond graph theory, the AMESim software is used for simulation analysis to verify the correctness of the bond graph model of the acquisition mechanism. The research results show that the designed oscillating flapping wing wave energy generation device acquisition mechanism responds quickly and stably, and the bond graph model basically matches the real system. The research process provides an effective reference for the development of the acquisition mechanism of the oscillating flapping wing wave energy power generation device.

Research on evaluation method of energy supply reliability of regional energy Internet

This paper studies the reliability evaluation technology of regional energy Internet and represents a reliability evaluation method considering the optimal load reduction strategy. The application scenario of regional Energy Internet with power system as the core is built. The specific form is that multiple Integrated Energy systems are connected to the superior distribution network through the tie line. The reliability evaluation index system of power system and regional energy Internet is introduced. Based on the modelling of components in the regional energy Internet application scenario in this paper, the operation model and two-state Markov model are mainly established for the renewable energy power generation devices, energy coupling devices and energy storage devices in IES. The optimal load reduction models based on load classification are established for the faults of distribution network lines and the faults of IES internal components connected to the distribution network in regional energy Internet respectively. Through the construction of different application scenarios, the load reduction situation under different faults and different component parameters is analysed, and the corresponding reliability index calculation and result analysis are carried out.

Energy Sharing-Based Energy and User Joint Allocation Method in Heterogeneous Network

Heterogeneous network, which is a key technology of fifth generation(5G) mobile communication system, can effectively solve the spectrum resource shortage in the communication system. However, with densified deployment of base stations (BSs) and growth of user quantity and communication data size, the system energy consumption of BSs has imposed enormous economic pressure on network operators. As a result, energy consumption decreases and cost of communication system becomes a problem that requires urgent solutions. Renewable energy power generation devices of BSs have provided an opportunity for solving this problem with the development of smart power grids. However, the production rate of renewable energy sources presents intense volatility because of the influence of weather factors. This condition brings new challenges to the energy allocation of communication system. Therefore, an energy sharing link between BSs was established in a heterogeneous wireless network, and the distance between macro-BS and micro-BS was taken as an index. The energy consumption-based energy and user joint allocation method and energy cost-based energy and user joint allocation method were proposed. The two multi-objective optimization problems were converted into two convex optimization problems, and the optimal allocation strategies were solved using convex optimization toolbox. Simulation results indicate that the energy consumption-based allocation method takes energy consumption as the optimization objective and makes the shared link transmit energy sources as few as possible. This way reduces energy consumptions of the link and the system. Starting from the economic angle, the energy cost-based allocation method considers the influence of energy price, coordinates energy allocation between BSs based on energy cost using the shared link, and optimizes energy allocation among BSs at each time slot. Therefore, the method can reduce the energy cost of the system by a large margin.

Modeling and Simulation of the Electrical Characteristic of Solid Oxide Fuel Cells

Solid oxide fuel cell (SOFC) is a new type of clean energy power generation device. In this paper, the SOFC model is established by introducing adjustable parameters, considering the voltage loss of concentration polarization, activation polarization and ohmic polarization, combined with the ideal gas state equation and the law of mass conservation. The simulation results show that the model can accurately reflect relationship between the input molar flow of each gas and the output characteristics of SOFC single battery, and adjustable parameters can be adjusted according to actual situation so the model has certain flexibility.

Research on Electric Energy Router Based on Limited Capacity Independent Power Supply System

At present in the frontier outpost, Sea Island and other area, which is not covered by the power grid, there are many disadvantages in the mode of power supply. Electronic energy router can provide multiple types of electric interfaces for new energy power generation device, storage device and load, and achieve energy bidirectional flow, at the same time, the AC and DC bus interface can be provided through the power electronic transformation technology. Take advantage of these features, an electric energy router based on a limited capacity independent power supply system is proposed. And the specific system structure and network structure are designed.

A Review of Wave Energy Extraction Technology

The current research on the utilization of wave energy has not formed a globally recognized technologically optimal wave energy power generation technology. The various types of wave energy power generation devices have different power generation principles and structural forms. Wave energy has the characteristics of wide distribution and high energy density, but it is also the most unstable type of ocean energy. Compared with other energy sources, wave energy has the characteristics of high energy density, and it is technically easy to realize the miniaturization of equipment, which contributes to the development of ocean resources. This article will mainly introduce current mainstream wave energy technologies, and explore their working principles and analyse their development trends.

Research on Efficiency of a Wave Energy Conversion System

The oceans are rich in wave energy that is green energy, and the wave energy are now being used to generate electricity on a massive scale. It can also be used as a single generator for beacon, buoy or underwater vehicle. Micro small wave energy power generation device is a kind of wave energy power generation devices, main characteristic is mobility is good, and can be directly assembled on various kinds of equipment for the power supply, with good prospects for development. The research object of the paper is a new adaptive reversing wave energy generating device belongs to micro-sized wave energy generating device. Using the upper and lower absorber blade groups, the low speed and large torque wave energy can be converted into electric energy which can be used for load and lithium battery charging.

Influence of installation deviation on dynamic performance of synchronous magnetic coupling

To improve dynamic characteristics of synchronous magnetic coupling, this paper mainly analyzed the influence of the installation deviation on the synchronous magnetic coupling’s dynamic performance used in the horizontal axis wave energy power generation device. Dynamic characteristics equations based on Lagrange equation are built in the paper to analyze the dynamic characteristic of synchronous magnetic coupling. The radial deviation, the angle deviation and the center-of-mass deviation are considered in the equation. The influence of those installation deviations on the synchronous magnetic coupling performance is analyzed based on the mathematical model. The results show that the rise time, the overshoot, the peak time, the adjusting time and the oscillation of the synchronous magnetic coupling are almost not affected by those installation deviations.

Experimental and Simulative Study on Accumulator Function in The Process of Wave Energy Conversion

Abstract In this paper, a floating-buoy wave energy converter using hydrostatic transmission system is studied. The entire work progress of wave energy power generation device is introduced, and the hydraulic transmission principles are emphasized through the simulation to verify the feasibility of design principle of hydraulic transmission system. The mathematical model of the accumulator is established and applied in the AMEsim simulation. The simulation results show that the accumulator plays an important role in the wave power hydraulic transmission system and that the correct configuration of accumulator parameters can improve the rapidity and stability of the system work. Experimental results are compared with the simulation results to validate the correctness of the simulation results. This would provide a valuable reference to the optimal design of wave power generation.

Experimental study on hydrodynamic characteristics of vertical-axis floating tidal current energy power generation device

To study the characteristics of attenuation, hydrostatic towage and wave response of the vertical-axis floating tidal current energy power generation device (VAFTCEPGD), a prototype is designed and experiment is carried out in the towing tank. Free decay is conducted to obtain attenuation characteristics of the VAFTCEPGD, and characteristics of mooring forces and motion response, floating condition, especially the lateral displacement of the VAFTCEPGD are obtained from the towing in still water. Tension response of the #1 mooring line and vibration characteristics of the VAFTCEPGD in regular waves as well as in level 4 irregular wave sea state with the current velocity of 0.6 m/s. The results can be reference for theoretical study and engineering applications related to VAFTCEPGD.

Design and experimental research of jack-up wave energy power generation device

In order to solve the problem of energy shortage and focus on the development of wave energy, a jack-up platform is used as the carrier, and a new type of wave energy power generation device is designed. Compared with other power generation devices, this new type of jack-up wave energy power generation device owns the advantage of wind and wave resistance, is continuous, highly efficient, stable, and strongly adaptable. By means of combination of theoretical analysis and physical test, the feasibility of the device implementation of wave power is explored. The results showed that the jack-up wave energy power generation device can normally work in the sea state, which verified the feasibility of the device. This device has achieved wave power efficiency by more than 15% of the technical indicators of the project and the desired effect. In general, the jack-up wave energy power generation device has achieved breakthrough in many aspects, and the overall technology has reached the leading domestic level.