DC-Link Capacitor Design for High-Speed Integrated Motor Drives: Reliability and System-Level Constraints

The DC link capacitor is one of the important components in Integrated Motor Drives (IMDs) in terms of reliability, and power density. This paper proposes a reliabilityoriented algorithm to select the DC link capacitor used in highspeed IMDs, considering both thermal stress and system-level performance constraints. The proposed algorithm relies on an excessive thermal load caused by the motor's high-frequency operation that contributes to heating the self-temperature of the DC link capacitor. Additionally, torque ripple-induced vibration is treated as a key system-level constraint due to its impact on mechanical integrity in high-speed applications. The thermal analysis is based on the applied mission profile, analyzing the hot-spot temperature over a mission profile, which cover a wide speed range operation. To handle the simulation time for a long mission profile, precomputed lookup tables are employed for capacitor current, copper loss, and core loss of the electrical motor. The simulation results confirm the effectiveness of the optimized capacitor selection in meeting lifetime by doing stressstrength analysis and system specifications requirements.