Regenerative Asynchronous and Synchronous Drives with Line-Frequency Switched Rectifier but without DC Link Component

Efficiency and regeneration capabilities of modern electric drives have become very important features for variable speed drive applications. Regenerative electric drives are therefore usually equipped with cost-intensive pulsed active front end topologies for the energy recovery mode. On the contrary, the much less expensive fundamental frequency switched front end is used. It has no electrolytic capacitor with its limiting effect on the operating temperature and lifetime. In addition to the converter topology, the used squirrel cage induction or alternatively the permanent magnet based machine provides different advantages with respect to the efficiency/torque characteristic of variable speed drives.