Real-time hardware-in-the-loop test platform for thermal power plant control systems

This paper deals with a real-time (RT) implementation of hardware-in-the-loop (HIL) systems for testing of control strategies in thermal power plants. Three implementation systems are developed and compared by testing, i.e., 1) fully simulated system, 2) non-real-time HIL system with OPC server, and 3) complete real time HIL deterministic system. The purposes of the present work are: to reduce downtimes in control system design and to determine which test platform is best suited in terms of accuracy, cost and efficiency for control system testing in thermal power plants. The three systems make use in implementation of the same nonlinear boiler-turbine model with decoupled multivariable adaptive control in order to provide precise comparative results. The boiler-turbine model is developed in Labview and runs on PC (fully simulated and non-RT HIL systems) and on a PXI real-time system (RT HIL system). The model employs dynamic linearization in order to compute the controller gains in an adaptive manner. The control strategy runs on PC (fully simulated system) and on a programmable logic controller (PLC) for the RT and non-RT HIL systems. The communication PXI - PLC is realized by decoding the S7 Industrial Ethernet protocol in Labview, and the communication PC - PLC is realized by means of an OPC Server. Comparative results on the three systems and controller performance are illustrated, the HIL-RT system presenting better performance in transient regimes.