Yuwei Sun

Review on the application and research progress of photovoltaics-ship power system

Facing with the problems of energy-saving emission reduction and marine pollution, the shipping industry have invested a great interest in developing “Green Ship” by utilizing the solar energy technologies. Solar ship, which integrates the solar photovoltaic (PV) system into its own ship power system, is becoming one kind of most promising and fastest developing green ship. In this paper, the development trend of solar ship is stated. For the solar PV system that integrated in ship power system, two different kinds of operation mode are analyzed, including off-grid and grid connected mode. In order to optimize energy managements of photovoltaic-ship power system (PSPS), the operation control strategy of multiple inverter equipment under grid-connected mode are studied. Moreover, the points of focus, methodology and original conclusion are detailed to explain the recent theoretical research progress.

Research on Evaluation Model for Characteristic of Solar Cell in Simulated Marine Environment Based on Information Fusion

Setting the characteristic of solar cell in simulated marine environment as research direction, a set of designs of hardware for experimental system based on information fusion are completed. On the basis of experimental system, compared the system model of functional and data type in the information fusion, an optimal multi-layer hybrid logic evaluation model based on information fusion has been established for further research on the affect and mechanism between the multi-factor of marine environment and solar cells. This research can provide an integrated theoretical method for accurately analyzing the power characteristic of solar cells in marine environment.

Research on the transient characteristic of photovotaics-ship power system based on PSCAD/EMTDC

With the problem of energy security, increasing prices of carbon-based energy sources and minimizing global warming, shipping industry have invested a great interest in developing “Green Ship” by utilizing the new energy technologies, such as nuclear energy technologies, wind energy technologies, solar energy technologies and tidal energy technologies. Among the renewable energy sources, the abundant solar energy is most applicable to conventional ships at sea. Based on this point, solar ship is becoming one kinds of most promising and fastest developing green ship. In this paper, the simulation model of photovoltaics-ship power system (PSPS) is established based on PSCAD/EMTDC platform. The transient characteristic of PSPS, especially the transient process at moment when the PV system is connected to main grid and the grid failure arises, is studied under two different operation condition normal sea-going and at port condition. The PQ control strategy is applied to settle the grid-connected operation between solar Photovoltaic (PV) and synchronous generator. The results show that the impact current under normal sea going condition is higher than that of berthing condition, but the impact current is soon disappeared and has no hazard to the safety of main grid due to the effectiveness of PQ control strategy. This paper has practical reference value to analyze the application of solar grid-connected PV system in the ship power system.

The I–V characteristics of solar cell under the marine environment: Experimental research

Solar cell is the core component of photovoltaic (PV) system on converting the solar radiation to electrical energy. Besides the solar irradiation and cell temperature, other environmental factors can actually affect the transient power output characteristic of solar cell located at the different district, such as humidity, wind velocity, shadow and dust, etc. Compared with the terrestrial environment, the marine environment is more severe and complicate, uncovering the cells I-V characteristic is the key point not only for calculating the energy conversion efficiency of integrated PV system, but also for evaluating reliability assessment from the view point of long-term utilization. In this paper, a series of comparative experiments are conducted to present the I-V characteristics of solar module when covered by the rainwater, seawater and salt particles layer respectively. The artificial illuminant with its intensity varying between 550 and 900 W/m2 is used to simulate the solar radiation in different weather condition. To reduce the experimental error, all the voltage and current data are processed by the method of curve fitting, and translated to the standard test condition based on the experiment and numerical simulation. It is shown that the I-V characteristics of solar cell is influenced when the surface of cover glass is covered by the transparent liquid and solid particles respectively, the energy conversion efficiency of solar cell that achieved in the comparative experiments involving the liquid factor is relatively higher than that of solid particle layer. The result is equivalent to changing the solar irradiation intensity and cells temperature with a certain rate simultaneously, but the mechanisms are classified in two different perspectives.

The application of hybrid photovoltaic system on the ocean-going ship : engineering practice and experimental research

ABSTRACT The constant development of electronic inverter technology has played a key role in promoting the exploration and development of solar ships. For the large-scale ocean-going ship platform, the critical issue of applying solar photovoltaic (PV) system is integrating PV equipment into the ship power system (SPS) without changing its original structure. This paper compares the existent technical differences for applying the off-grid and grid-connected PV system in the SPS and proposes the basic design principles for marine integration applications. The 5000 PCTC ro-ro ship is set as the application object, on which a hybrid PV system with large-capacity lithium battery storage device is designed and installed as an independent subsystem. The typical feature of this hybrid PV system is that it can implement operation mode switching between off-grid and grid-connected, according to the evaluation on solar radiation resource, power load requirement and state of charge in the lithium battery. The test results show that this PV system has a stable operation characteristic under different operation modes. In addition, this ship-based PV power system has automatic and reliable operation management capability, which could effectively reduce manual control frequency and maintenance workload of a marine engineer.

Hybrid thermal-photovoltaics water distillation equipment design and its thermodynamic analysis

With the rapid development of social economy, the worldwide shortage of water resources is becoming increasingly prominent, especially in the coastal countries and regions of high population density areas. Market demand is driving the development of sea water desalination technology to the direction of large scale, high efficiency, low energy consumption and low cost. The paper uses solar radiation heat — photovoltaic integrated energy, a seawater desalination device was designed based on the two stage heating and cooling system, the water is heated by two stages, by the solar collector and the photovoltaic electric heater respectively, then the condensing heat exchanger is used to process the saturated vapor condensation obtained by two stage heating to obtain fresh water. With the method of thermodynamic energy balance and energy-level balance analysis, the energy efficiency and related parameter variation characteristics are respectively analysis based on energy saving and energy level matching. By calculating the heat loss (heat transfer, heat convection and heat radiation) of seawater desalination device, the optimization equation for calculating the middle control temperature between solar collector and photovoltaic electric heater is established. And, the interactional relationship among initial temperature, middle temperature and system energy level difference is analyzed The results show that the energy level difference of single PV electric heating is maximum, when the energy gap of thermal and PV combined seawater distillation is small relatively, meaning that the energy utilization is more reasonable for high energy efficiency; the relationship among environment temperature, middle temperature and energy level difference is nonlinear; the energy level difference reaches the lowest point 0.18, when the initial environment temperature is 28 Ό and the middle temperature is controlled at 55.4°C.

Theoretical model research on I-V characteristics of solar cell under the marine environment

Solar cell is the key component of photovoltaic system on converting the solar radiation to electrical energy. The environmental factors such as solar irradiation, temperature, humidity and dust can directly affect the power output characteristics of solar cells that applied in the different area. Compared with the terrestrial environment, the marine environment is more severe, and the power output characteristics of solar cell in this environment have not been studied with all environmental factors considered. This study aims to establish an appropriate approach on this issue from three aspects, including classical equation, environmental factors and theoretical model. Firstly, the classical equation of I-V characteristics of solar cell is introduced and the limitation of its computational boundary condition is expressed by taking the real environment into consideration. Then, the environmental factors analysis is mainly focused on the difference between terrestrial environment and marine environment, especially the effect factors that can change I-V characteristic of solar cell. Thirdly, two theoretical models (Energy Conservation Model and Parameter Correlation Model) are respectively established to represent the interrelationship between I-V equation and five feature parameters, such as humidity, wind velocity, liquid immersion, particulate matters and ship movement. In the energy conservation model, a control surface is introduced to explain the heat convection, heat conduction and heat radiation process within a typical solar cell module. Based on the universality of cause-effect connection, a decoupling function is introduced in the parameter correlation model for representing the relationship between multiply environmental factors and cell temperature during the photovoltaic conversion process. These two models can be definitely used to study the efficiency and reliability problem of solar cell that applied in other severe environments.

Study on effect of ship low frequency vibration on the output characteristics of PV cells under different solar irradiation

This paper analyzes the influence mechanism of the ship low frequency vibration on the output characteristics of PV cells under direct light and scattered light. And the simulation model in the MATLAB/Simulink platform has been put up, and some related experimental studies have been carried out based on the experiment platform, which can simulate ship vibration environment. The results of the simulation analysis and the experimental study all show that it is possible to lead to slight fluctuation on the output of PV cells and there is no obvious effect on fluctuation range with frequencies of the vibration. The impact effects on the output characteristics of PV cells are different under different solar irradiation.