A communication and synchronization multiplex architecture of the multi-controller system for the CHB converter

In converters possessing multiple distributed controllers the synchronization of and the communication between the various controllers are important topics requiring careful consideration. The controllers should be able to transmit data and commands to each other so that different control modes can be selected, reference values updated, parameters shared and so forth. Synchronization is important particularly for actions such as PWM generation, where strict timing and coordination between modules is required. Some industry communication bus technologies, such as EtherCat and PowerLink, can cyclically distribute time information to all devices on the bus for the purpose of synchronization. However, these technologies are expensive and complex to implement. In this paper, a solution providing both communication and synchronization within a distributed control system is presented. The solution is low cost and enables high precision synchronization. We have implemented this solution within the multi-controller system of a CHB converter. Experimental results are given.