Selection of the Filter Capacitor for Power Supplies using 1-Phase Diode Rectifier
Diode bridge rectifiers with capacitor-input filters are commonly used at the input stage for power supplies operating from the single phase mains input, as they provide a cost effective solution in the lower power range. However, as there is no simple design rule existing in published literature that gives a reasonable prediction based on real-life conditions, the design of the rectifier-capacitor stage is still a trial and error or based upon experience. This paper presents an approximate (but simple) solution based upon empirical relations, for the prediction of the currents involved and specifies the capacitor, so that it can be selected.
Lifetime analysis of aluminum electrolytic capacitor subject to voltage fluctuations
This paper evaluates the changes in the ripple current for an electrolytic capacitor used in the dc-side of a single-phase rectifier circuit when subjected to input voltage fluctuations. The study has been undertaken in order to analyse the potential impact on capacitor lifetime. The key effect is that the capacitor ripple current, as a consequence of voltage fluctuations, increases dramatically and this phenomenon keeps deteriorating as the frequency of the voltage fluctuations increases. Simulations and experimental work confirm this phenomenon. Since the power loss and temperature rise are dependent on the capacitor equivalent series resistance (ESR) and ripple current components, an increase in ripple current under voltage fluctuation conditions is likely to accelerate this process, resulting in a reduced lifetime.
The Determination of Operating Data and Allowable Ratings of Vacuum-Tube Rectifiers
Among the operating data of thermionic rectifiers only transformer voltage, output voltage, and output current are readily accessible. In determining the permissible limits of operation however, peak current, inverse voltage, and plate dissipation must be considered. This paper gives formulas and a graph to determine these latter values from the former, to rate limits of operation, and to draw the dynamic characteristics for any valve.