Reversible AC Drive Systems Based on Parallel AC–AC DC-Link Converters

In this paper, two reversible single-phase-to-three-phase ac drive systems are proposed. They are composed of an induction motor fed by two parallel single-phase-to-three-phase dc-link converters without isolation transformers. Suitable modeling and control strategy of the systems based on odq approach, including the unbalanced case, are developed. The proposed topologies permit reducing the harmonic distortion and presents fault tolerance characteristics. Even if the number of switches is increased, the total energy loss of the proposed systems can be lower than that of a conventional one. It is shown that the reduction of the circulating current is an important objective for the system design. A single-phase-to-three-phase dc-link converter generalization has been proposed as well. Simulated and experimental results are presented.