The invention relates to a direct current stabilized current power supply which realizes low ripple by IGBT series-parallel connection, and the invention belongs to the field of automatic control technology and power electronic technology and relates to a power change circuit based on a large capacity IGBT apparatus. The power change circuit comprises an incoming filter circuit, a phase shifting circuit, an input end rectification filter circuit, an energy storage circuit, a front reduction voltage chopper circuit, a front passive filter circuit, a back reduction voltage chopper circuit, a back passive filter circuit, an output end passive filter circuit, a voltage sensor circuit, a current sensor circuit and a control circuit used for controlling a whole circuit to work. Water cooling or forced air cooling can be applied to the direct current stabilized current power supply, and the direct current stabilized current power supply has the advantages that the power supply has high stability of current in a long term, low voltage (current) ripple, fast response, high regulation precision, small size, high efficiency and small noise of a device.