Combined transformer suitable for metro traction power supply system

A combined transformer suitable for a metro traction power supply system comprises an iron core, and a rectifying winding for providing a multiphase alternating current power supply for a rectifier, an energy feedback winding for feeding back alternating current electric energy converted by a converter to an alternating current side and a high-voltage winding which are sequentially wound by taking the iron core as a concentric circle, the rectification winding, the energy feedback winding and the high-voltage winding are all arranged in the same magnetic circuit, and a combined transformer formed by the rectification winding and the energy feedback winding shares one iron core and one high-voltage winding. According to the combined transformer, the functions of an energy feedback transformer and a traction transformation rectifier transformer are integrated in the same transformer to achieve the purpose of sharing one iron core and one high-voltage winding, and the combined transformer is only provided with o