RESISTORLESS PRECHARGING

摘要

A boost PFC converter includes a rectifier, a converter and an output stage comprising an output capacitor where the DC output voltage is provided across the output capacitor. The rectifier includes four rectifying elements connected in a full bridge configuration where the upper two of these four rectifying elements are thyristors and where the lower two are diodes. In that the thyristors are controlled such as to be open for only a part of each half period of the input voltage, the amount of current per half period that is passed to the output capacitor is controllable and can be made very small. Accordingly, the charge current for precharging the output capacitor can be controllably limited such that a bulky precharge resistor is not required anymore to avoid high inrush currents.

主权项

1. Converter arrangement including an input stage comprising two input terminals for connecting an AC input voltage, a converter stage for converting the AC input voltage to a DC output voltage and an output stage comprising an output capacitance, where the DC output voltage is provided across the output capacitance, the converter arrangement further including a controllable switch arranged in a current path from one of the two input terminals to the other and including said output capacitance and a control unit adapted to control the controllable switch for precharging the output capacitance at a startup of the converter arrangement, characterised in that the control unit is adapted to control the controllable switch during startup such that a duty cycle of the controllable switch during at least one half period of the input voltage is between 0 and 1.