Introduction to the working principle of DLC filter

a. When the secondary winding of the transformer is up-down and negative, since the voltage output from the secondary winding of the transformer is a positive-negative and alternating rectangular wave, the negative half-cycle is removed by adding D1 rectification, and the current is passed through the inductor after the positive half-cycle is rectified by D1. L stores and stores magnetic energy. This part of the current charges C1, the other part is used for load RL, and D2 is cut off.

b. When the input positive pulse disappears, then the self-inductance voltage generated by the secondary winding of the transformer is upside down, so the rectifier D1 is cut off, the filter has no input voltage, and the current supply of the load RL is composed of two parts, part of which is composed of The magnetic energy stored in the inductor is converted into electrical energy, the current direction is consistent with the original current direction, and the loop current iL is formed by the freewheeling diode D2, and the other is that the current supplied by the C1 discharge is -ic1.