Review of Active Thermal Control for Power Electronics: Potentials, Limitations, and Future Trends

The main factor that drives the aging of power semiconductor modules is the thermally induced stress caused by the maximum temperature and temperature swings. This thermally induced stress is usually counteracted in passive designs with oversizing of components, which brings additional cost to the system. This is a major limitation of future power electronic systems that are required to be more reliable with reasonable cost and for many applications to be lighter and smaller. Active thermal control (ATC) is a possibility to reduce the thermal stress of components during real-time operation without the need to modify the expensive converter power stage. Many studies have shown the potential of ATC to not only extend the lifetime of power converters because of the reduced stress, but also to increase the converter devices utilization by pushing them into their thermal limits with proper control. This makes ATC an appealing way to realize the contradicting reliability, cost, and power density requirements. This paper provides an overview of the benefits and objectives, structure, and implementation possibilities of ATC. It also provides and overview of the limitations and disadvantages of many ATC strategies. Based on this discussion, it highlights key issues that must be addressed by future research. Among them is minimizing the impact of different ATC strategies on the power losses, operational cost, and output voltage and current quality.