Models for design and control of a solar-hybrid vehicle with a tracking solar roof

Abstract

Our planet faces significant challenges in the twenty-first century because energy consumption is expected to double globally during the first half of this century. Faced with increasingly constrained oil supplies, humanity must look to other sources of energy, such as solar, to help us meet the growing energy demand. A useful measure of the level of a country’s development is through its energy consumption and efficiency. Excessive fossil fuel energy use not only has caused severe and growing damage to the environment from greenhouse gas emissions and oil spills, but also has brought political crises to countries in the form of global resource conflicts and food shortages. Solar and other forms of renewable energy offer a practical, clean, and viable solution to meet our planet’s growing environmental and energy challenges. Solar radiation is the most important natural energy resource because it is a renewable, free and largely diffused source. The Sun provides the Earth with an enormous amount of energy. Naturally, the Sun has always held the attention of humanity and been the subject of worship by many cultures over the millennia, such as the Egyptians, Incans, Greeks, and Mayans, among many others. The potential of solar energy to produce heat and electricity to be supplied for our modern economies in a variety of productive activities has been widely demonstrated but not yet widely adopted around the globe due to relatively cheap fossil fuels. The main problem of this kind of energy source is that it is not constant during the day and not readily dispatched. In contrast, modern lifestyles demand a continuous and reliable supply of energy. However, there are ways to overcome these shortfalls. In chapter 1 there is a general presentation of solar irradiance and the main solar angles: global solar irradiance is composed by diffuse, reflected and direct radiation. To direct radiation the geometrical relationship between the Sun and the Earth must be known. Nowadays solar technologies are involved to industrial maturity: to capture solar energy as much as possible firstly arrays with an optimal fixed tilt have been developed, then solar tracking arrays. For many of reasons, especially energetic, environmental, economic, a big interest nowadays has been developed for hybrid vehicles, particularly hybrid electric vehicles HEV; but in recent years HSV are attracting increasing interest. The last ones use solar energy. These kind of vehicles are described in chapter 2. It must be underlined that there is a great difference between hybrid solar vehicles and solar cars: in fact solar cars now do not represent a realistic alternative for traditional cars, because they depend only on sun availability and have high costs. Instead HSV do not have problems concerning the autonomy range, because they have an electric motor and also a traditional combustion engine. However until now in literature a little interest has been given to the hybrid solar vehicles despite HEV but at the University of Salerno a prototype of HSV has been developed and another one is going to be developed. Formulating the control algorithm for determining the fuel efficient power split between two energy sources is referred to as the supervisory control or energy management problem. In chapter 3, the main control strategies, used also for the energy management of HEV, are examined. Control strategies may be classified into non-causal and causal controllers respectively. Furthermore, a second classification can be made among heuristic, optimal and sub-optimal controllers. Great importance has given to three different strategies: Dynamic Programming DP, Genetic Algorithm GA and Rule–Based strategy RB. For each one the techniques of optimizations are described. An HSV vehicle has been modeled, and for this model especially RB strategy and GA optimization have been applied to see the most convenient one to apply on HSV prototype developed at University of Salerno. So a