Research On Control System Of Wind-solar-didsel-battery Hybrid Power Generation

With the development of human society, demand of electricity is growing. For someislands and mountainous areas rich in natural resources, setting up hybrid renewable energysystem in those areas is not only an effective way to solve the electricity supplying problemin remote areas, but also consistent with the national energy policy. This paper carries outthe research that focuses on the control strategy in hybrid energy system, which refers to alot of related books and literatures. The main contents are as follows.At the begining of this paper, a typical stand-alone hybrid renewable energy powersystem’s structure and functions of some key components will be introduced. Mathematicalmodels of the main components in the hybrid power system are also established in the firstpart, including wind generator system’s model, photovoltaic(PV) power generation’s model,fuel cost of diesel generator’s model and the model of batteries.After the analysis above, this thesis starts the optimization design of the hybrid powersystem. The progress of the optimization is completed in two stages. In the first stage,energy management strategy and an optimal design model are established which use theminimum operating cost of a power system as the target function and the power balancetheory as the constraint condition. In the second stage, Harmony Search algorithm is appliedon the result from the first stage, it’s one of the new optimization algorithms that has theadvantages of simple structure, fast convergence and so on. Then this research achievesresonable optimal results by simulating in MATLAB.The working model of each subsystem is the key factor for the efficiency of hybridpower system, as a result, research of controlling strategies for each subsystem from internallevel to guarantee they are working in the best state is needed. At the beginning of this part,it gives several common control methods for wind power generation, photovoltaic powergeneration, battery charge and discharge. After that, the most suitable method for makingcontrol strategies for each of the wind power generation, photovoltaic power generation,battery charge and discharge are picked out from the control methods above. Last but notleast, setting the ‘maximum power tracking control’ and ‘load tracking control’ as the twomain factors, establishing the systems’ controlling strategies for wind power generation andphotovoltaic power generation subsystems. Meanwhile, a brief analysis of battery chargeand discharge control strategy is also being given. Those strategies that mentioned abovehave been all passed the simulation to prove their correctness. In the last part, the integrated and coordinated control strategy is established, based onresearch of the systems from an overall standpoint. First, according to the weatherconditions, the system’s operating models are divided into four categories (wind, PV,batteries, diesel engine). Then, it gives the analysis of how to use digital switch controlmethod to make the start-stop system working in a sequence as wind, PV, batteries, dieselengine and an inverse one to ensure the rational allocation of energy between themulti-energy source. Second, summarizes the integrated and coordinated control strategyunder the four operating modes which is based on the power balance theory aiming at thestable operation of the hybrid power system. After that, analysis of the coordination degreebetween each hybrid power subsystem in detail, which is working in those four models.Experimental results show that the integrated and coordinated control strategy had achievedthe anticipated goals.