Fail-operational motor system configuration for functional safety of autonomous driving Hyun Kyung Roh1, Infineon Technologies Korea Co.Ltd, South Korea, SUNG HOON KIM2 , Infineon Technologies Korea Co.Ltd, South Korea, Yeon Yong Shin3 , Infineon Technologies Korea Co.Ltd, South Korea KEYWORDS – Motor system, Autonomous driving, Functional Safety, Fail-operational Research and/or Engineering Questions/Objective The motor system is essential for autonomous driving. One of the significant challenges in developing the motor system for autonomous driving is achieving the safety. Therefore, many major tiers are using redundant concept for motor system. However, duplicating entire components and using identical system configurations have a potential possibility of the common cause failure risks. This paper suggests the motor system redundant concept with a proposed motor system configuration different from the existing method by using new control type of gate driver integrated circuit to improve the safety. Methodology The risk of common cause failure has more potential possibility in a previous redundant concept that duplicates all hardware and software. Therefore, a redundant concept combining the existing method and the different type of method is required for diversity with achieving the independence. In the traditional way, microcontroller generates pulse width modulation signal and put each input into the three phases high side and low side. However, in case of the proposed motor system configuration, the pulse width modulation module is inside the gate driver integrated circuit. Therefore, microcontroller only sends the duty cycle, center position and measurement position to gate driver integrated circuit through serial peripheral interface. The hardware and software are configured completely different than the traditional way. In this paper suggests a redundant concept that includes a new type of gate driver to reduce the possibility of common cause failure. Results In this paper adapts the redundant concept using two different motor system configurations instead of the previous duplicated redundant concept. In addition, a proposed motor system configuration is suggested that is different from the traditional motor system configuration. The system can be designed with different hardware and software rather than duplicated hardware and software. This makes a system with diversity that can meet independence from a safety point of view. Test result with configuration will be presented. Limitations of this study This current study is focused on gate driver configuration of motor system. To achieve motor system safety, the other components such as microcontroller and power management integrated circuit must also be considered. What does the paper offer that is new in the field including in comparison to other work by the authors? This suggestion about redundant motor system concept and configuration. It can be implemented as a motor system that achieves hardware and software diversity that satisfies independence by reducing possibility of common cause failure. Conclusions In this paper suggests a redundant concept that includes a proposed motor system configuration. According to this suggestion, the motor system can have diversity in terms of hardware and software, so independence can be secured. And as a result, motor system can be designed with improved safety in autonomous driving.
Ms. HyunKyung Roh, Senior engineer, Infineon Technologies