A Real-Time Data Storage Method for AC Servo Motor Drives Using Micro SD Card

Abstract

In this study, we propose a real-time data storage method to store the high-frequency motor control data of AC servo motor drives. The Micro Secure Digital Card (MSDC) is chosen as the storage device because of its cost-effectiveness and space efficiency. However, the MSDC has a fatal drawback of lengthy write time, which is solved by applying a double-buffering algorithm and distributing the MSDC writing load based on the multi-core architecture of the microcontroller unit (MCU). The proposed data storage method is implemented using a commercial AC motor drive system with an MCU integrating two digital signal processor (DSP) cores and an MSDC socket. From experimental results, it is demonstrated that the proposed method achieves a remarkable MSDC writing speed of approximately 2.44 Mbps, which is sufficient for realtime storage of critical motor control data at fast 10 kHz motor control cycles. Consequently, the proposed method can be used for motor drive optimizations and applications requiring a vast amount of motor control data storage.INDEX TERMS Real-time data storage, micro SD card, AC servo motor drive, multi-core MCU, doublebuffering algorithm.