Innovative HV Measurement: Noninvasive Digital Tester (NDT) for Enhanced EV Diagnostics

In electric vehicle (EV) systems, managing multiple high voltage (HV) domains controlled by digital logic ICs presents significant measurement challenges. Traditional HV measurement systems are often complex and costly, requiring the monitoring of numerous simultaneous signals that need to be monitored for each HV domain. This study aims to develop a cost-effective and compact measurement system that simplifies analysis and troubleshooting tasks, focusing exclusively on digital signals. The proposed system consists of an optocoupler, Trigger Schmitt, and shielded cable to ensure accurate signal monitoring. Evaluations were conducted across various frequencies and duty cycles to determine the system's performance in terms of duty cycle error. Results indicate that the system maintains low-duty cycle errors at frequencies up to 500 kHz, making it suitable for high-accuracy applications. At moderate frequencies (1 MHz and 2 MHz), the system performs well at higher duty cycles but shows increased errors at lower duty cycles. At higher frequencies (3 MHz,5 MHz, and 7 MHz), significant errors were observed, particularly at lower duty cycles, indicating a need for further calibration.