A simple correction scheme for phase and sequence of three phase firing circuit in phase angle control applications

A simple scheme for use in a four-wire AC voltage controller system is presented. This scheme automatically provides the correct firing pulses for the working thyristors irrespective of any mistake introduced while connecting the firing circuit. The scheme can also readjust the firing circuit against any phase and/or sequence alterations. This feature leads to elimination of the manual adjustment usually needed in such cases. Another advantage of the scheme is the ability to detect if the system contains faulty thyristors. Experimental results are given to verify the principle of operation of the proposed scheme. © 1998 Taylor & Francis Ltd.GENNUM Corp., General Electric Canada, Bell Sympatico Canada, IEEE Canad