DIGITAL IMPLEMENTATION OF A RELAY EXPERIMENT BASED PID AUTOTUNING ALGORITHM FOR CURRENT MODE CONTROL OF A MULTIPHASE BUCK CONVERTER

In recent years, there has been a significant expansion of systems operating in islanded mode without connection to the power grid. For these systems, which are often used in sensitive applications such as navigation and radar systems, as well as in light electric vehicles, it is crucial to ensure the necessary autonomy and robust operation in the presence of disturbances and changes in the system’s nominal parameters. These systems mostly utilize power electronics devices, acting as voltage or current actuators, which are digitally controlled due to significantly greater flexibility when dealing with load-side and power source uncertainties. In such cases, the demands for stable and efficient power supply posing challenges in the design of control systems can be met with new software solutions designed for real-time applications. This paper presents a methodology for developing software that performs autotuning of current regulators. The autotuning algorithm is based on the principle of a digital relay experiment and is carried out during system initialization, eliminating the need for prior knowledge of the controlled system’s parameters or additional user intervention. The same mathematical operations used in PID controller algorithms are employed, meaning no additional hardware or upgrades to the existing digital signal processor (DSP) are required. The proposed methodology reduces the time required for implementing such systems in practice, particularly in the design and verification phases of closed-loop performance. Validation of the proposed methodology was conducted through simulations on a Hardware-In-the-Loop (HIL) platform.