Bipolar bidirectional dc converter, and control method and control device therefor

A bipolar bidirectional DC converter, comprising:

• at least two valve group series being distinguished from each other according to connection relationship between the valve group series and a low-voltage side port of the bidirectional DC converter, and comprising:
• a Type-I valve group series, a positive electrode of a low-voltage DC port of the Type-I valve group series forming a positive electrode of the low-voltage side port of the bipolar bidirectional DC converter;
• and
• a Type-II valve group series, a positive electrode of a low-voltage DC port of the Type-II valve group series being connected to a negative electrode of the low-voltage DC port of the Type-I valve group series and forming a neutral point of the low-voltage side port of the bipolar bidirectional DC converter, and a negative electrode of the low-voltage DC port of the Type-II valve group series forming a negative electrode of the low-voltage side port of the bipolar bidirectional DC converter;
• wherein each of said valve group series comprises:
• a low-voltage DC port;
• a high-voltage DC port, positive electrodes of all the high-voltage DC ports being connected together to serve as a positive electrode of a high-voltage side port of the bipolar bidirectional DC converter, and negative electrodes of all the high-voltage DC ports being connected together to serve as a negative electrode of the high-voltage side port of the bipolar bidirectional DC converter;
• and
• at least three AC ports, each of said AC ports being connected to a magnetic element;
• and
• wherein the bipolar bidirectional DC converter further comprises at least six magnetic elements, one end of each said magnetic element is connected to a corresponding AC port, and the other ends of the magnetic elements connected to all the AC ports in a same valve group series are connected together.