Analysis of a Resonant Converter Controlled by Triac
Analytical and experimental considerations in the constant voltage transformer are presented. The constant voltage transformer consists of a linear reactor, a linear transformer, a capacitor, a triac, and a feedback circuit. The feedback circuit is used to make the triac fire precisely at any angle from zero to ¿/2 so as to keep output voltage constant. An analysis of this circuit is presented in which the higher harmonic currents generated in the triac are neglected and the output voltage is assumed to be kept constant. The experimental results agree well with the theoretical value with respect to the load characteristic, the voltage characteristic, the power factor, and the jumping phenomenon.
Analysis of the ferroresonant transformer with a rectified output in the low-line-voltage minimum-line-frequency full-load condition
Most previous analyses of the ferroresonant transformer address the unrectified-output AC-load case, and do not include some or all of the important loss mechanisms. The analysis reported in this paper addresses the rectified-output DC-load case and includes the stray losses. The low-line-voltage minimum-line-frequency full-load condition is the focus of this analysis because it is the worst-case condition for supplying power to the load. Assumptions about the operation of the transformer in this worst-case condition lead to a simplified equivalent circuit. Given equivalent-circuit element values, a special-purpose time-domain computer simulation analyzes transformer performance in the periodic steady-state condition. This analysis technique is used to find equivalent-circuit element values for which the transformer winding currents are a minimum and the input power factor and conversion efficiency are at a maximum. >
Wall-to-bed heat transfer in circulating fluidized beds
Heat Transfer from the wall of a circulating fluidized bed to the fast bed suspension has been investigated for several materials. The range of investigation includes dense and dilute phase fast fluidization and pneumatic transport. The overall heat transfer coefficient was found to be a function mainly of cross-sectional average suspension density. Effects of superficial velocity and solids mass flux were obscured by their interrelationship to the suspension density. Two models from the literature are evaluated using present and published data.