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

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 real-time 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.