A HIERARCHICAL CONTROL ARCHITECTURE FOR A PEBB-BASED ILC MARX MODULATOR *

Abstract

The idea of building power conversion systems around Power Electronic Building Blocks (PEBBs) was initiated by the U.S. Office of Naval Research in the mid 1990s. A PEBB-based design approach is advantageous in terms of power density, modularity, reliability, and serviceability. It is obvious that this approach has much appeal for pulsed power conversion including the International Linear Collider (ILC) klystron modulator application. A hierarchical control architecture has the inherent capability to support the integration of PEBBs. This has already been successfully demonstrated in a number of industrial applications in the recent past. This paper outlines the underlying concepts of a hierarchical control architecture for a PEBB-based Marx-topology ILC klystron modulator. The control in PEBB-based power conversion systems can be functionally partitioned into (three) hierarchical layers; system layer, application layer, and PEBB layer. This has been adopted here. Based on such a hierarchical partition, the interfaces are clearly identified and defined and, consequently, are easily characterised. A conceptual design of the hardware manager, executing low-level hardware oriented tasks, is detailed. In addition, the idea of prognostics is briefly discussed. and interfaces, but also standardisation of the control architecture. A PEBB can be seen as a defined set of hardware that integrates power semiconductor devices, gate drivers, protection, and other components. Sufficient intelligence needs to be embedded into a PEBB so that it is capable of processing electric power with a defined set of characteristics. PEBBs are interconnected to build a system as illustrated schematically in Figure 1. The integration of these blocks, irrespective of how they are configured together, necessitates the support by the overall control architecture in order to produce the desired system behaviour and performance. Prior work in this area [2] demonstrated that a hierarchical control architecture has the inherent capability to support the integration of PEBBs.