full converter- Inverter mode

Discussion in 'Homework Help' started by haditya, Nov 18, 2006.

  1. haditya

    Thread Starter Senior Member

    Jan 19, 2004
    Consider this
    A full converter, using thyristors in bridge configuration, with R-L load and a L large enough to cause perfect smoothing of current ripple.
    Now when used as a controlled rectifier, we find that continous current flows(atleast theoritically and in textbooks) in the load and the load voltage has negative excursions.
    Now since the load voltage may be negative with positive current flowing through it, it may be thought of as operating in "inverter mode" for a part of the conduction cycle and in rectifier mode for the other part(when voltage is positive).
    textbooks also say that the converter may not work as an inverter unless there is a DC source in the load capable of supplying power to the source with the fiiring angle greater than 90'.

    even wiithout the source the average voltage across the load may be negative with positive current(current flowing into the load) for firing angles greater than 90'. so isnt this a case of converter acting like an inverter?
    or is it just acting in inverter mode as it isnt external power that the converter is supplying to the source, but just returning what the source had supplied to it in the positive half cycle (between 90'-180')?