Testing of digital controllers using real-time hardware in the loop simulation

Designing and testing digital control systems for power electronics applications can be costly and time consuming. In this paper, a rapid, low-cost prototyping and testing procedure for digital controller design is proposed using real-time hardware-in-the-loop (RT HIL) simulation. First, the control subsystem is prototyped using conventional simulation techniques. After the performance of the control logic is evaluated using non real-time simulation, the control subsystem is tested with RT HIL simulation. RT HIL simulation replaces the simulated control system with a real hardware controller, which interacts with other virtual models that are simulated in real-time. This increases the realism of the simulation and provides access to hardware features currently not available in software-only simulation models. Consequently, RT HIL makes the testing of new control equipment fast, safe and reliable. To perform RT HIL experiments, a real-time simulation platform has been implemented using virtual test bed (VTB) and its real-time extension (RTVTB). As a demonstration of the proposed procedure, a digital controller for an H-bridge inverter is designed, implemented and tested. The frequency response analysis is also performed on the closed-loop system.