Control system design for the MOD-5A 7.3 mW wind turbine generator

This paper provides descriptions of the requirements analysis, hardware development and software development phases of the Control System design for the MOD-5A 7.3 mW Wind Turbine Generator. The system, designed by General Electric Company, Advanced Energy Programs Department, under contract DEN 3-153 with NASA Lewis Research Center and DOE, provides real time regulation of rotor speed by control of both generator torque and rotor torque. A variable speed generator system is used to provide both airgap torque control and reactive power control. The wind rotor is designed with segmented ailerons which are positioned to control blade torque. The central component of the control system, selected early in the design process, is a programmable controller used for sequencing, alarm monitoring, communication, and real time control. Development of requirements for use of aileron controlled blades and a variable speed generator required an analytical simulation that combined drivetrain, tower and blade elastic modes with wind disturbances and control behavior. An orderly two phase plan was used for controller software development. A microcomputer based turbine simulator was used to facilitate hardware and software integration and test

Left, Right, and Center: Strategic Information Acquisition and Diversity in Judicial Panels

In the last fifteen years, a number of empirical studies of multi-member judicial panels have documented a phenomenon popularly known as "panel effects. " Two principal findings of this literature are: (1) the inclusion (non-pivotal) members from outside the dominant ideology on the panel predicts higher reversal rates of administrative agencies that are “like minded ” with the panel’s median voter; and (2) when mixed panels do not reverse, they frequently issue unanimous decisions. These apparently moderating effects of mixed panel composition pose a challenge to conven-tional median voter theory. In the face of this challenge, many scholars have offered their own explanation for panel effects (including collegial-ity; deliberation effects, whistle-blowing, and others). In this paper, we propose a general model that (among other things) predicts panel effects as a byproduct of strategic information acquisition. The kernel of our argument is that (non-pivotal) minority members of mixed panels have incentives to engage in costly searches for information in cases where the majority members would rationally choose not to do so. As a result, the inclusion of ideologically diverse members may induce more information production in a way that increases the likelihood that a mixed panel will overturn ideologically allied agency actors. Our informational account — if true — has normative implications for the composition of judicial panels in particular, and for deliberative groups more generally