Fault Detection of On-board Battery Chargers for PHEVs
The aim of this project is to develop a systematic method for analysis and detection of faults in on-board battery chargers for plug-in hybrid electric vehicle (PHEV) applications.
On-board battery chargers are widely used in PHEV applications. A fault in the charger circuit can sometimes be detected by the control circuitry which can terminate the charging process to minimize the damage. However, there might be some faults that couldn’t be detected by the usual fail detection mechanisms. This can be harmful for the battery or other parts of the system; because the fault is not detectable and charging process continues but with a lower quality. For example, if a capacitor at the charger’s output fails to an open state, the fail may not be detected and the charging process continues with a high current ripple that can reduce the battery lifetime, for instance.
There are two stages in the charger circuit: a front end grid-connected pre-regulator with unity power factor (PFC) that performs AC/DC conversion and an isolated DC/DC stage which provides the required galvanic isolation and battery charging control. Each component of the system may fail to function properly.
The goal is to provide a systematic methodology to perform analysis of the fault modes of charger by considering statistics and severity of each individual fault. Circuit analysis, power electronics simulation and practical verifications considering the severity and statistical description of each fault are the main headlines of the project.