In order to extend the lifetime and save the system cost, the film capacitor is applied to the dc link of interior permanent magnet synchronous motor (IPMSM) drives. Many active damping control methods have been carried out to improve the drive system stability, which needs the accurate value of the dc-link film capacitor. In this letter, an online dc-link capacitance estimation method is investigated for reduced capacitance IPMSM drives, which do not need any additional signal injection or sensor. The power coupling characteristics are analyzed to obtain the instantaneous power of the dc-link capacitor from the inverter and the grid sides. The bandpass filter is applied to extract the dc-link voltage and capacitor power with twice the frequency of the grid voltage. The dc-link capacitance could be estimated by the fundamental component of the dc-link voltage. The proposed method can be used for different kinds of load types and motor types of the drive system. The experimental results are performed to verify the estimation method, and the estimation error is within 1%.

中文翻译：

---

用于降低直流链电容 IPMSM 驱动器的直流链电容器在线估算方法


为了延长使用寿命并节省系统成本，薄膜电容器应用于内置式永磁同步电机（IPMSM）驱动器的直流环节。为了提高驱动系统的稳定性，人们采用了许多主动阻尼控制方法，这需要直流母线薄膜电容器的精确值。在这封信中，研究了一种用于减少电容 IPMSM 驱动器的在线直流链路电容估计方法，该方法不需要任何额外的信号注入或传感器。分析功率耦合特性，获得逆变器和电网侧直流母线电容器的瞬时功率。带通滤波器用于提取频率为电网电压两倍的直流母线电压和电容器功率。直流母线电容可以通过直流母线电压的基波分量来估计。所提出的方法可用于不同类型的负载类型和驱动系统的电机类型。实验结果验证了估计方法，估计误差在1%以内。