Thermal Mapping of Power Semiconductors in H-Bridge Circuit

In this paper, a universal H-bridge circuit is used as a loading emulator to investigate the loss and thermal models of the power semiconductor. Based on its operation principle and modulation method, the dominating factors’ (e.g., power factor, loading current, fundamental frequency, and switching frequency) impact on the thermal stress of power semiconductors is considerably evaluated. The junction temperature in terms of the mean value and its swing is verified by using Piecewise Linear Electrical Circuit Simulation (PLECS) simulation and experimental setup. It helps to allocate the loading condition in order to obtain the desired thermal stress

An Improved Discharge Profile-based DC-link Capacitance Estimation for Traction Inverter in Electric Vehicle Applications

DC-link capacitor is an important part of traction inverters in electric vehicles (EVs), contributing to cost, size, and failure rate on a considerable scale. This paper proposes a non-invasive DC-link capacitance estimation method based on the capacitor discharge profile during the turning-off transition of a traction inverter. The proposed method relies on the existing control and measurement of the traction inverter without the need for software modifications and hardware updates. It minimizes the new risks introduced into the system operation because the estimation procedure is implemented after vehicles are parked. A novel correction solution is proposed to secure the estimation accuracy while also reducing the sampling requirements. Compared with conventional estimation methods, the proposed scheme outperforms in complexity and accuracy. The proof-of-concept experiments based on a scaled-down inverter prototype and a full-scale traction inverter for EV applications verify the feasibility of the proposed method.<br/