Análise das estratégias de controle de temperatura em uma estufa de secagem

Abstract

This work presents the development and simulation-based evaluation of control strategies applied to a laboratory drying oven whose original commercial controller became non operational. The thermal dynamics of the system were experimentally characterized, allowing the identification of a First Order Plus Dead Time (FOPDT) model capable of representing the oven’s heating behavior under disturbances and variations in power. Based on this model, a Proportional–Integral (PI) controller was designed using Internal Model Control (IMC) tuning rules, and a static feedforward action was incorporated to anticipate the steady-state power required to reach a given temperature setpoint. The performance of the PI+FF strategy was compared with the traditional On-Off control in multiple operating conditions, including different temperature setpoints and abrupt drops in temperature simulating door opening. The results show that the PI+FF controller eliminates oscillations, improves transient response, enhances temperature accuracy, and achieves higher energy efficiency for low and medium thermal loads. In contrast, the On-Off approach exhibited substantial oscillations, potential actuator stress due to frequent switching, and limited capability to maintain high temperatures with stability. The findings indicate that physical implementation of the PI+FF controller is a feasible and effective solution to restore and improve the oven’s operation, offering a robust alternative for high-inertia thermal processes.