The utility model discloses a five level DC converting circuit and contain generator excited system of this circuit. The utility model discloses an among the five level chopper circuit, first switch tube one end is connected in excitation output positive end, and the DC power supply anode is connected to the other end, second switch pipe one end is connected in excitation output negative terminal,connects electric capacity series -wound loop mid point behind the 6th diode of other end series connection, third switch tube one end is connected in excitation output negative terminal, and the DCpower supply negative terminal is connected to the other end, first respectively the reverse parallel connection is in first to the third switch tube to the third diode, and fourth diode one end is connected in power supply positive terminal, and the other end is in succession in excitation output negative terminal, and the 5th diode one end is connected in the power negative terminal, and the other end is in succession in excitation output positive end. The utility model discloses based on excitation current signal output data's characteristics, when realizing that the output of five level direct current chopping of excitation voltage, excitation power bi -directional flow move, can reduce the switch tube loss, improve full -controlled excitation system efficiency.