公开(公告)号：IN3517CHN2014A

公开(公告)日：2015-10-09

申请号：IN3517CHN2014

申请日：2014-05-09

Applicant: ABB TECHNOLOGY AG

Inventor： HASLER JEAN PHILIPPE ,  MONGE MAURO

IPC: H02J3/18 ,  H02J3/26

Abstract: A multilevel converter and a method for controlling a multilevel converter is provided. The multilevel converter is a single phase converter with one phase leg (1) or a three phase converter with three phase legs (1A C) the phase legs of the three phase converter are interconnected in a star configuration. The (1) or each (1A C) phase leg comprises switching cells (11 21) and each switching cell (11 21) comprises semi conductor switches (41 51) arranged to selectively provide a connection to a corresponding energy storage element (42 52). The converter also includes a controller (31) which is provided to monitor the DC voltage (VDC) of the energy storage elements (42 52) and the controller (31) is provided to control the switching of each switching cell (11 21). The phase leg (1) of the single phase converter or each phase leg (1A C) of the three phase converter comprises two parallel branches (10 20) of switching cells (11 21) the branches (10 20) being configured in a closed circuit. The method includes monitoring (105) the voltage levels of each of the energy storage elements and balancing (107) the voltages of the energy storage elements wherein the balancing includes circulating a current (104 107) within the two branches of the (1) or each (1A C) phase leg of the multilevel converter.