Topology Construction, Modeling, and Control of Multilevel Inverters Without Shoot-Through Problem

Shoot-through is an inherent topology defect of bridge-type inverters. Especially for multilevel inverters, the addition and compensation of dead-time have higher requirements for control strategies. This article proposes a topology construction regulation of three-phase inverters, which can convert any existing two-level or multilevel bridge-type inverter into a new topology without shoot-through problem. Also, the new topology makes it easier to achieve capacitor balance. With the proposed regulation, two typical multilevel topologies are given, and their working principles are analyzed. They have new switching modes that are not available in conventional bridge topologies and help to achieve dc capacitor balance. Because the filtering plant is coupled in the topology, the traditional inverter transfer function is unsuitable for the newly generated topology. Therefore, power bond graph method is applied to establish the topology mathematical model. A new switching model called switch-diode combined junction is proposed, which is suitable for both discrete and continuous control signals. Based on this, the control system complex vector model in synchronous rotating frame is established and the multiconstrained complex coefficient controller is designed to improve the dynamic performance of inverters. Finally, the simulation and experimental results are given to verify the correctness of the theoretical analysis.