Smart Induction Motor Variable Frequency Drives for Primary Frequency Regulation

摘要

This article proposes an induction motor variable frequency drive to investigate its potential in handling smart grid's frequency. This can thus mitigate the grid reliance on expensive power plants. To this end, a primary frequency controller is presented enabling the drive to reduce its power in proportion to grid frequency drop. The dynamic limitation of the drive due to load's inertia is considered through a motor's speed rate limiter. Moreover, an appropriate inertia emulator is proposed for the smart drive by inspiring the inertial response of a direct-on-line motor. The impacts of speed rate, maximum reserve power and motor driven load's inertia on dynamic behavior of the smart motor load during the frequency support are addressed. Besides, the effectiveness of the smart drive's contribution in primary frequency regulation of the IEEE 39-bus test system is explored. In this regard, a critical droop coefficient that guarantees the maximum reserve power delivery for the smart drives is analytically derived. Finally, the proposed approach is extended to include the critical droop derivation for a set of smart drives with different sizes and priorities to rank their participation in primary frequency regulation process.