High-power four-quadrant converter system

A high-power four-quadrant converter system, comprising a double-secondary-side oil-immersed rectifier transformer with an output connected to four three-phase bridge type thyristor rectifiers, wherein every two rectifier bridges share a group of rectifier transformer secondary sides;

• wherein
• two rectifier bridges sharing a group of rectifier transformer secondary sides are inversely connected in parallel, one of the two rectifier bridges realizes a forward output, and the other one of the two rectifier bridges realizes a reverse output;
• two groups of rectifier bridges of outputting in a same direction are configured to operate independently or in parallel;
• and when the two groups of rectifier bridges operate in parallel, reactors are connected in parallel to realize current sharing;
• the rectifier bridges for a forward output and a reverse output realize free smooth transition under control of a controller, so that a four-quadrant operation of an output current is realized;
• both an alternate current (AC) part and a direct current (DC) part are comprised, wherein the AC part comprises a high-voltage cable terminal, AC isolation switches, a lightning arrester, a rectifier transformer, an AC bus, and high-voltage buses interconnected between equipment;
• an AC high-voltage cable is connected to the rectifier transformer through the cable terminal, the AC isolation switches, and the lightning arrester;
• wherein the cable terminal, the AC isolation switches, and the lightning arrester are mounted on a same steel structure support member, and the steel structure support member requires reliable multi-point grounding;
• the DC part comprises the rectifier bridges, the reactors, the controller, and DC buses interconnected between the equipment;
• the four rectifier bridges are connected to inputs of the reactors through DC water-cooling buses, and outputs of the reactors are connected in parallel and output through DC isolation switches;
• the rectifier bridges comprise the two rectifier bridges sharing the rectifier transformer secondary sides, wherein one rectifier bridge is named a forward bridge for the forward output, the other rectifier bridge is named a reverse bridge for the reverse output, and the forward bridge and the reverse bridge together become a rectifier unit;
• and the forward bridge and the reverse bridge sharing the rectifier transformer secondary sides are not allowed to work simultaneously, and a clearance distance between the two groups of rectifier units is greater than or equal to 2 m.