Research On Energy Management And Control Of A Wind/solar Hybrid Power System

Due to the issues of environmental and resources, reducing cost and growing matured technology of wind/solar power, the research about the wind/solar hybrid power system are focused on more and more attention. Owing to the stochastic change of the wind power, solar energy and load, the design of the energy management and control for small and medium-sized wind/solar hybrid power generation system is one of the major difficulties in practical application of the hybrid power system. The design should be able to control the power supply and demand. Under such background, the energy management and control of the hybrid power system have been studied, the hardware and software system based on PLC has been designed, not involving principal computer. The system operation has been also studied by using fuzzy control in the paper. The main works of this paper are as follows:Firstly, the structure and characteristic of the hybrid power system are analyzed. Besides, the balance between energy supply and demand, the management of battery charging and discharging, the control of grid and load, have been discussed. Then six operation states of the system are defined. Each subsystem operation in relevant state has been described in detail.Secondly, fuzzy control algorithm is used to manage and control the hybrid power system. In this paper, the state of charge (SOC) of storage battery and the error between generated power and load power, are the input, while the hybrid power system operation state is the output. The control rule table has been calculated off-line, then proved by simulation in Matlab Simulink.Finally, a PLC-based energy management and control system has been designed. Its hardware is integrated to a power distribution cabinet. It, jointed into the network in Modbus protocol, can co-work with other subsystems. Meanwhile, the PLC program based on fuzzy control is designed. According as the load, the energy management and control system without other principal computer, can effectively achieve the functions of the energy distribution, control and monitor.The simulation and system operation showed that the proposed energy management and control strategies of the hybrid power system as well as hardware and software design, based on fuzzy control theory, is feasible and reasonable.