Fuzzy-Logic-Based $V/f$ Control of an Induction Motor for a DC Grid Power-Leveling System Using Flywheel Energy Storage Equipment

Since natural distribution power generation systems such as wind energy contain electric power fluctuation, flywheel energy storage (FWES) equipment for power compensation is used. Fuzzy-logic-based V/f control of the induction motor is proposed for the speed sensorless power-leveling system in this paper. Only two sensors, including one DC voltage sensor and one DC current sensor, are utilized. The flywheel is composed of two modes, namely, the speed picking-up control mode and the power control mode. According to the DC-link average current of an inverter, the rotating speed of the flywheel in the speed picking-up control mode is detected by regulating the output frequency and the output voltage based on fuzzy logic control. The power control mode consists of the outer voltage loop and the inner current loop. Although the outer loop is also realized by fuzzy logic control, the inner loop is the key object in this paper, i.e., the proportional and integral gains of a proportional-integral regulator are optimized by means of fuzzy logic reasoning for the purpose of the reliability and rapid response of leveling power. The experiments are carried out with the FWES equipment of 40-kJ energy, and the results verify that the proposed method is reliable, and better dynamic and static performance is demonstrated.