Projeto de um calorímetro de fluxo tipo fechado com dupla camada para medição de perdas de potência

Abstract

The measurement of power losses in power electronic devices represents a critical challenge, particularly in environments dominated by harmonics and electromagnetic interference (EMI), which compromise the accuracy of conventional electrical input-output methods. To mitigate this limitation, this work proposes the development of a double-jacketed, closed-flow calorimeter, which offers an alternative immune to such disturbances by quantifying the heat generated by the DUT. The system utilizes an STM32 to execute a hierarchical control strategy: a digital PI controller for external heat rejection and a hysteresis control for internal circulation. The thermal plant was formally identified as a First-Order Plus Dead Time (FOPDT) system, allowing for precise tuning of control parameters. Experimental results, validated across test batches of 25 W and 45 W, demonstrated a thermal stability of ±0.1 °C in the gap and an overall accuracy exceeding 90% in the worst-case load scenario. The project consolidated a low-cost tool for loss characterization, integrating oversampling techniques and digital filtering to mitigate instrumentation noise.