Topology of energy-fed three-port cascade converter of hexagonal structure and control method

Abstract

The invention relates to the technical field of power electronic converters, in particular to topology of an energy-fed three-port cascade converter of hexagonal structure and a control method, The topology effectively combines a hexagonal converter with a traditional H-bridge cascaded multilevel converter driven by the existing medium and high voltage system motors, and then connects it with theAC power network through the multi-winding phase-shifting transformer, so that it can be extended to a three-port structure with single input and two outputs, which can meet the operating requirementsof the two-motor system under different operating conditions. As the front-end input is added to the module units on part of the bridge arm of the hexagonal converter, the number of power electronicdevices and the secondary side windings of the phase-shifting transformer required by the converter can be greatly reduced. At the same time, in order to solve the problem of system power imbalance caused by the default of front-end input of some units, the internal relationship between loop current and converter bridge arm power is further analyzed. Through a power balance method based on loop current control, the topology can realize stable operation and energy interaction.

Description

technical field [0001] The invention belongs to the technical field of power electronic converters, and in particular relates to the topology and control method of an energy-feedback type three-port cascaded converter with a hexagonal structure. Background technique [0002] With the rapid development of power electronic devices and their control technologies, multilevel converters have gradually become the main form of high-power conversion devices. Among them, the cascaded H-bridge converter adopts the structure of multiple single-phase full-bridge converters connected in series to achieve high voltage and multi-level output, and has the advantages of less output voltage harmonics, small output voltage change rate, and easy expansion of the modular structure. Advantages provide great convenience for later industrial production and maintenance, so it has been widely used in the industry, especially in the field of drive and speed regulation of AC asynchronous machines. [...

AI Technical Summary

Problems solved by technology

However, if the two motors run simultaneously, the system lacks an energy front-end, and if the dual-motor system has surplus energy output, the energy cannot be effectively utilized, so the working form of this topology is not flexible enough, and the scope of application is not wide enough.

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