Implementation of hardware-in-the-loop system for drum-boiler-turbine decoupled multivariable control

This paper focuses on developing a hardware-in-the-loop (HIL) system for a boiler-turbine process, employing decoupled adaptive control based on gain scheduling technique. The used model is a 3 × 3 non-linear strongly coupled system adapted to fit a real thermal power plant of 16 MW. The main purpose of this work lies in implementing, comparing and validating the proposed HIL method over classic simulation methods applied on the present complex structure, rather than analyzing control system performance (which was studied in a previous paper). The proposed investigation contains two sections for integration: i) simulation environment for the boiler-turbine process carried out using Labview running on a PC under a general purpose operating system, and ii) control algorithms implemented on industrial real-time Siemens programmable logic controller (PLC). The control algorithms are made in two different ways: by Labview Virtual Instruments (VI) on PC, and by ladder-logic program on PLC, for comparison purpose. Data exchange between parties is provided by an OLE for process control server (OPC Server) at the software level, and by an Industrial Ethernet bus at the physical level. The synchronization between PLC and PC, which does not have a real-time operating system, was a challenge. Test results show that the proposed HIL method is validated even in these conditions.