Clamp type built-in current sensor using PCB in high-voltage power modules

High reliability is required for power modules because they are increasingly demanded as key devices in an energy-saving society. However, commercially available current sensors like current transformers and Rogowski coils are still of large size. Therefore, it is impossible to measure the current in small parts. In addition, long wiring with large sensors reduces the performance of power modules. In previous studies, we proposed a current sensor of PCB Rogowski coil with a fishbone pattern. The sensor is sufficiently small and thin with high accuracy for power module application. The PCB current sensor can be used as a built-in current sensor in power modules from the viewpoint of size. However, the sensor requires further improvement to be attached to bonding wire from a usability perspective. We propose a new pattern for the clamp-type PCB sensor and fabricate the PCB sensor as a built-in sensor in a power module. With the new pattern, it is possible to move and widen the gap for clamping. The signal error is small even though the sensor is inclinedly attached to the bonding wire. The accuracy is confirmed by a comparison between the clamp-type PCB sensor in the module and a commercially available current sensor outside the module. The clamp-type PCB sensor can be applied for intelligent power modules as well as current measurement for power electronic converters.