Active Thermal Management and Fault-Tolerant Control for Switching Power Converters with Sequence-Based Control

With the developments in semiconductor technology, power electronic devices have had a crucial role in power systems. They are employed in a different variety of applications, including but not limited to energy conversation and grid connection for renewable energy sources, motor drive systems in electric vehicles and industrial systems, and AC/DC power conversion in the ship power system (SPS). Especially, medium-voltage DC (MVDC) distribution systems are highly interested in future ship power systems, therefore, power converter devices and their control systems will be commonly used in the ship. The increasingly using of power electronics in power systems leads to new challenges including but not limited to reducing Total Harmonic Distortion (THD) and system cost, improving reliability and lowering the system complexity. In addition, some of the applications may have limited weight and space capacity such as wind turbines and SPS. Thus, the weight and size of the power converter and its cooling system should be taken into account. To minimize the size of the power converters, high-frequency switching is used to reduce the required passive filters. However, this causes additional thermal stress on semiconductor switches due to increasing of the switching losses which also have a negative impact on the cost of energy. Power converters and their control algorithm must provide highly efficient power conversion to reduce the cost of wasted power and energy dissipation to minimize the necessary cooling system. In addition to this, the aging and losses of switching devices in the power converter are mainly related to its junction temperature. One of the main approaches to improve the lifetime of semiconductors is the ability to control the junction temperature of the semiconductor module by controlling the switching losses during the switching state while providing power quality in the required limits and maintaining voltage stability, referred to as active thermal control. Sequence-based control is chosen in this study for its ability to deal with the system nonlinearities, control multiple constraints simultaneously with guaranteeing the system requirements and ensure the stability. The method is developed and the simulation is performed using MATLAB/Simulink software to validate the performance of the algorithm and tune the control parameters. The simulation results show that the proposed method can control the switching losses by influencing the switching sequence for a two-level three-phase active front end rectifier. For the validation, the influence of the proposed method on a two-level three-phase active rectifier is demonstrated experimentally by using Control Hardware-in-the-Loop (CHIL) setup. These will be tested utilizing the Texas Instrument (TI) C2000 XL LaunchPad controller and Opal-RT real-time simulator to perform CHIL experiments.