Power converter for two current directions and method for its operation

摘要

This power converter for two current directions is used for coupling a three-phase mains to a DC voltage network at an approximately constant voltage, with flow of energy being possible in both directions. For this purpose, the power converter has a rectifier (B1) and an invertor (B2), the AC-voltage sides of which are in each case directly connected to the three-phase terminals (1, 2, 3) of the three-phase mains. As opposed to an all-pole, direct, DC-voltage side antiparallel connection, the rectifier (B1) and the invertor (B2) are directly connected together on the DC-voltage side by only one pole, whereas the other sides are connected together via an electronic power switch (S). This switch (S) interacts with a diode (D) and a smoothing coil (L) in feedback operation as a step-down controller, while the invertor (B2) is simultaneously operated with a fixed maximum triggering delay angle ( alpha max). In supply operation, the invertor (B2) and the power switch (S) are inactive. Drive-regulator devices, for example, may be connected to the DC-voltage network supplied using such a power convertor, which devices take in energy during drive operation and supply energy during braking operation. <IMAGE>