The series bridge converter (SBC): Design of a compact modular multilevel converter for grid applications

Abstract

Access from the University of Nottingham repository:http://eprints.nottingham.ac.uk/37544/1/The%20Series%20Bridge%20Converter%20SBC %20Design%20of%20a%20Compact%20Modular%20Multilevel%20Converter%20for %20Grid%20Applications.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the University of Nottingham End User licence and may be reused according to the conditions of the licence. For more details see: http://eprints.nottingham.ac.uk/end_user_agreement.pdf A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. Abstract-This paper presents a novel hybrid modular multilevel voltage source converter suitable for grid applications. The proposed converter retains the advantages of other modular multilevel topologies and can be made more compact making it attractive for offshore stations and other footprint critical applications like city infeeds. In this paper, the basic operating principle and design criteria for the converter implementation are presented. The submodule capacitor requirements which have significant influence on the size of a converter station are also evaluated and compared to the MMC.The performance of the converter is supported by simulation results from a representative medium voltage scaled demonstrator.

A Parallel Connected Unfolding Bridge (PCUB) Multilevel Converter for HVDC Applications

“…The 2ω current that needs to be injected is either in phase or in anti-phase with the 2ω voltage components in the CLs depending on the direction of power flow. Since V LC is imposed by the AC side and no additions can be made to it, i 2ω is driven by adding 2ω components only in V T C as shown in (13).…”

“…The AAC has almost a similar structure to the MMC except for director switches in the upper and lower arms and the use of full-bridges as submodules [12]. Another hybrid multilevel converter topology is the Series Bridge Converter (SBC) proposed in [13] with series connection of converter phases on the DC side. The SBC topology has the benefit of a significantly more compact footprint than the MMC but the drawback of a limited power transfer capability during AC faults, due to the constraints imposed by the series connection of phases on the DC side.…”

“…In this paper, the PCUB, a new hybrid VSC topology is introduced in order to overcome the drawbacks of the SBC [13] while maintaining smaller station footprint than the MMC because of the need for smaller sub-module capacitors in the chainlinks. During the design stage, this is achieved by setting the AC side transformer turn ratio to an optimum value that minimises the energy storage requirements of the converter.…”

Control and Experimental Validation of the Series Bridge Modular Multilevel Converter for HVDC Applications

“…The concept of the SBC [19], [20] has been derived as an evolution of the PH-M2C topology, with the addition of an array of series full-bridge SMs (SFBs) in between the CLs and H-bridges. The SFBs allow decoupling the AC and DC side voltages to achieve full reactive power control.…”

“…However, the addition of the SFBs into the converter topology adds more complexity to the system, in particular making the internal energy control and balancing more challenging. The aim of this paper is to provide a detailed analysis of the basic energy management concept introduced in [20], with a focus on the control design and experimental validation of the topology and the proposed control.…”