Multimegawatt Power Sources For Commercial Space Operations

The commercialization of space will require power for everything from lights to climate control and especially for the industrial processes that are planned to take advantage of the zero-g environment. This power requirement can vary from a few kilowatts to several megewatts, depending on the particular commercial operation. This paper discusses the concepts that are available to supply this power, the different ways the power might be utilized, and some of the problems associated with development and utilization of the power source

A solar powered distillation plant and pump station for use in ocean side desert areas

There are thousands of miles of ocean shoreline which could sustain a productive human existence if sufficient fresh water were available for human consumption and for irrigation of crops. While solar stills can be built to produce fresh water at or close to sea level, raising water to a height sufficient to irrigate crops, even with minimum water usage crops, requires a significant amount of energy. This paper describes a ``no-external power`` process by which seawater can be purified and raised to a height above sea level sufficient to carry on a productive living in certain areas of the world. This device, the Solar Evaporation and Pumping System (SEAPS) is described as to function and areas of use

Very Light Rail (VLR) technology - a new, simple, safe, cost-effective environmental solution to meet future transportation needs

An increasing number of papers, government programs, and studies, are directed toward the economics of lighter weight vehicles in mass transit. The objectives of these activities are generally directed toward the increased energy efficiency of the fighter vehicles or the benefits to the infrastructure-less wear, repair, or construction cost, or both. Some systems studies of potential magnetic levitation concepts have minimized the size of the vehicles in order to increase the operational flexibility of the system. CyberTran was designed and developed from the ground up as a small vehicle transportation system with the primary objectives of (1) reducing the capital and operating costs of high speed rail and transit systems and (2) maximizes rider appeal and safety. The potential for significant savings in capital cost with a small vehicle rail system like CyberTran has been evaluated. This paper discusses the operational benefits which can be realized with a rail system based on small, light weight, and computer controlled vehicles. CyberTran was developed at the Idaho National Engineering Laboratory, a U.S. Department of Energy Research and Development Laboratory in Southeastern Idaho

Gating Methods for High-Voltage Silicon Carbide Power MOSFETs

The objective of this thesis is to assess the challenges associated with driving Silicon Carbide (SiC) power devices, and to compare the potential gate drive methods for these devices which address those challenges. SiC power devices present many benefits that make them suitable for next generation automotive, power utility grid, and energy management applications. High efficiency, increased power density, and reliability at high-temperatures are some of the main benefits of SiC technology. However, the many challenges associated with these devices have prevented their adoption into industry applications. The argument is made in this thesis that the gate driver is a key component in providing proper control to enable the reliable and high performance of these devices. Thus, as the main control mechanism, the gate driver topology should be carefully considered in the design of SiC-based converters. In this thesis, the main issues and challenges of operating SiC power devices will be explored, and the common mitigation techniques will be discussed. Next, the switching operation of the SiC power MOSFET and the loss analysis will be performed for the voltage-mode and current-mode drivers. Additionally, a solution incorporating a multi-level voltage-mode driver is proposed as an alternative to the other methods. The comparison of these techniques and their ability mitigate EMI and other negative consequences of fast-switching while minimizing switching energy losses will be analyzed. This is done through the comparison of the methods based on the analytical approach, through the use of simulations using device models, and through experimentation. The multi-level driver is found to be good alternative to the conventional voltage-mode driver, and is thus assessed in detail in the experiments. Finally, the considerations for the experimental setup using the double pulse test (DPT) is also discussed. Conclusions are made based on the performance of the device under multi-level turn-off, and future considerations for enabling the next generation high-voltage SiC MOSFETs are discussed