Investigation of current sensing techniques for a high bandwidth application : Focusing on Hall-Current Sensing

Abstract: With the ongoing surge in electrification within the automotive industry, the demand for high-power inverters is steadily on the rise. Furthermore, these inverters are now expected to handle increased power loads while maintaining enhanced efficiency. Fulfilling these demanding prerequisites, places significant importance on the current sensors that meticulously monitor each phase of the inverter. This thesis tackles the deep study of a current sensor that has been chosen by Scania to be introduced in the new generation of inverters. The chosen sensor is based on the Integrated Magnetic Concentrator (IMC)- Hall technology. Given its innovative nature within the company’s scope, there exists a keen interest in investigating its performance. The principal parameters that will be assessed during this thesis are accuracy, temperature dependencies, bandwidth and noise immunity. The evaluation of these properties will be done though the creation of a test rig capable of producing current pulses, spanning the range necessary for the sensor evaluation. A high-end current sensor based on the fluxgate technology will be used as a reference during the assessment. Across the course of the research, diverse experiments and modifications to the testing setup will be undertaken to accommodate the assessment of each individual parameter. The acquired data will be summarized and presented with simplified figures. The results of this study show that the accuracy of the sensor highly depends on a proper end of line calibration and a mechanical assembly, in other words, the sensor must be perfectly centered within the IMC. Moreover, the study identifies linear relationships between temperature and accuracy, while exponential correlations are found between the impact of an external magnetic field and its distance.