ENERGY, ENVIRONMENT, AND ADVANCES IN POWER ELECTRONICS (Keynote Address)

Power electronics will play a significant role in global energy conservation and environmental protection in the 21st century, in addition to its traditional role in industrialization and energy systems. The world is now at the critical crossroad in the energy scenario. Energy has been the lifeblood for continual progress of human civilization. Since the industrial revolution about two centuries ago, global energy consumption has been increasing by leaps and bounds to accelerate our living standard in this planet. Currently, about 87% of our total energy is generated from fossil fuel (coal, oil and natural gas), 6% is generated in nuclear plants, and the remaining 7% comes from renewable sources (hydro and wind). Unfortunately, the world has limited fossil fuel and nuclear power resources. Currently, our overdependence in fossil and nuclear fuels is causing pollution and safety problems in the environment, which are now dominating issues in the world. With growing energy demand, enforcement of more rigorous environmental standards and shortage of traditional energy sources, the cost of energy will tend to increase prohibitively in future jeopardizing our aspiration for high living standard. It appears that conservation of energy and correspondingly reducing the environmental pollution is of extreme importance for the future. Power electronics can play significant roles in solving these problems. The world has enormous reserve of environmentally clean and safe renewable energy resources, such as wind and photovoltaics, where the processing of power is highly dependent on power electronics. Particularly, wind energy is already competitive with that of fossil fuel because of recent technology advancement of variable speed wind turbines, power electronics, drives and control techniques. USA, Germany, Denmark and the developing countries like India and China have ambitious expansion programs for wind energy. The concept of future hydrogen economy and widespread use of fuel cell cars are based on conversion of wind energy and storing in the form of hydrogen. With increasing cost of gasoline, electric and hybrid vehicles that use power electronics extensively will help urban pollution problem. Besides these important roles, the importance of power electronics can hardly be overemphasized for global industrialization which is going through booming period, particularly in the developing countries. The main reason is that power electronics technology has gone through dramatic advancement in the recent years. Many innovations in power semiconductor devices, converter topologies, PWM techniques, machine drives, analytical and simulation techniques, DSPs and ASIC chips, and advanced control methods have made the technology so rich today.. Very recently, artificial intelligence techniques, such as fuzzy logic, neural network and genetic algorithm have brought a new frontier of the technology. The presentation will review in the beginning the global energy generation scenario, projected depletion of fossil and nuclear fuels, environmental pollution problems, and techniques for energy conservation and environmental protection with the important role of power electronics. The increasingly important renewable energy sources (wind, PV and fuel cells) which are heavily dependent on advanced power electronics will be discussed. Then, the advances and trends of modern power semiconductor devices, power converters, drives and control will be reviewed systematically. Finally, the prognosis of power electronics for the 21st century will be highlighted.