科研之友
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摘要
Conventional distributed control has achieved a great deal of success in multi-parallel cascaded H-bridge (CHB) power supplies. However, conventional distributed controllers can have a seriously imbalanced output power due to a mismatch of the hardware or control parameters and form an unstable circulating current path between the CHB converters, which can lead to a couple of problems. (1) The stability and tracking performance of the branch current can become degraded. (2) The current-sharing reactor can be easily saturated. To optimize all the branch currents of multiple parallel CHB power supplies, a master-slave carrier-based model predictive control method is proposed in this paper. This control strategy can achieve an optimized current tracking performance and effective circulating current suppression. In addition, through carriers, H-bridge interleaving and branch synchronization can be easily achieved, which fixes the switching frequency. Thus, the advantages of model predictive control and interleaving can be combined. Based on the generalized branch current predictive model derived in this paper, when more than two paralleled CHB converters have different output powers, an optimized branch current response can be achieved and circulating current can be eliminated. Simulation and experimental results verify the effectiveness of the proposed method.
