Bus paralleling controller with CAN interface for High Power Converter modules

This paper presents the development of the Controller and efficient Control algorithms for enabling modularity and bus paralleling of High Power Converters employing high speed Controller Area Network bus (CAN). Presently paralleling of Converters requires common current sensors to sense the load current, which restricts the level of redundancy of the system as well as limits the number of Converter modules which can be put in parallel. The newly developed controller can support “n” number of units since no common current sensors are involved. The Controller uses the fast space vector control with the aid of Digital Signal Processor and the fast CAN bus to meet the specific requirements. The proposed scheme operates one of the converters in the voltage control mode to regulate the load bus voltage and all other converters are operated in the current control mode. This ensures zero circulating current among the converters. The current reference for the current control mode is derived from the voltage controller and passed through CAN bus communication link. The token passing algorithm implemented in the system permits to arbitrarily switch off and switch on the systems, eliminating the master- slave concept. The system shares the active, reactive and harmonic currents equally at load side. Two 10 kVA Converters are built to validate the performance.