DC Chopper Operation in SMES Design
If the inductor coil L1 is charged and then isolated from the supply and then the power transfer happens from L1 to L2, the switches S1 and S2 has to undergo PWM to provide controlled output current from L1 to L2. Meanwhile, the switches S3 and S4 are off and the charging circuit for L2 is completed as: L1-&gt;S2-&gt;D4-&gt;L2-&gt;D3-&gt;S1-&gt;L1. The capacitor C has been employed to forward bias the IGBT S3 and simultaneously S4 during the charing cycle of L2. It is charged when the switches S1 and S2 are off, through the loop: L1-&gt;D1-&gt;C-&gt;D2-&gt;L1.