Traction converter with secondary filter circuit

The invention provides a traction converter with a secondary filter circuit. The traction converter comprises a rectifier circuit, a secondary filter circuit and an inverter circuit, which are sequentially connected between the positive and negative ends of a bus. The rectifier circuit includes at least one four-quadrant rectifier connected in parallel. The secondary filter circuit, which is used for filtering out second harmonic, includes at least two filter capacitors connected in parallel, at least two filter inductors connected in parallel and at least one discharge resistor, wherein the at least one discharge resistor is connected in series and then connected in parallel to the two ends of the filter capacitors, and the filter inductors and the filter capacitors are connected in series. The inverter circuit includes at least one three-phase inverter connected in parallel, and each three-phase inverter is connected to at least one traction motor. By filtering out second harmonic in bus voltage, the voltage input to the inverters is accurate and reliable, and the traction motors can be driven safely and reliably.