Asian Journal of Industrial Engineering1996-3386xxxx-xxxxAsian Network for Scientific Information10.3923/ajie.2020.1.10KuntianM.A.HuaL.I.YuX.U.12020121Background and Objective: In the current MMC-HCDC engineering, the average voltage of the capacitor of the converter mostly adopts the sorting class algorithm. However, under this algorithm, after re-ordering each control cycle, the sub-modules will be heavily re-switched and the switching state of the sub-modules will change frequently. As a result, the service life of the sub-modules will be reduced and the investment in MMC-HVDC engineering will increase. So, it is important to research the switching frequency of sub-modules in MMC-HVDC engineering. Materials and Methods: In current research, the sub-module switching mode is divided into three types. Only change the switching status of Dn sub-modules with the largest or smallest capacitor voltage which have been selected. Results: The sorting algorithm which was already known and the Max-Min algorithm are compared in the PSCAD/EMTDC and the sub-module switching frequency of Max-Min algorithm is reduced from 1100-262.5 Hz. Max-Min algorithm has no negative effect on the amplitude of capacitance voltage fluctuation of the sub-module. The operation period is shortened and the operation burden is reduced. Conclusion: The computation time of the Max-Min function is shorter than that of the current sorting algorithm. Compared with the sorting algorithm which was already known, the switching frequency of the Max-Min function is smaller. It provides a new optimization strategy for the capacitance uniform voltage control under the sorting algorithm commonly used in the MMC-HVDC engineering.]]>Rong, F., Y.S. Xu and S.D. Huang,2018Hu, Y., Y.T. Liu and S. Zhang,2018Ni, S.W., J.H. Su and S.L. Zhou,2017Gao, Y., G.D. Qiang and Y.B. Gao,2019Wang, Y., C.R. Liu, G.Y. Li, J. Sun and S.X. Wu,2019Zhang, X., F. Wu, K. Zhou and X.X. Zhu,2019Xu, Z.,2012Cao, L.M., Q.E. Zhao and J.C. Gao,2017Wang, T.Z., G.Q. Bu, S.S. Wang, Y.F. Dong, J.X. Hou and Y. Wang,2018Xiao, H., G.G. Gao and Z.Y. Pei,2015Su, Y.M., S.P. Su and L. Li,2019Pan, W. and H.R. Zou,2019Guo, B.P., S.P. Su, H. Fu, H.Q. Huang and L.P. Zhou,2019Wei, Y.F., Z.N. Wei, G.Q. Sun, Y.P. Zheng and B. Yu,2012Guan, M.Y. and Z. Xu,2011Wang, S.Y., K.Y. Shi, M. Chen and D.H. Xu,2013Luo, Y.J., Z.X. Li, Y.H. Li and P. Wang,2015Chang, F., Z.P. Yang, J. Chen, H.L. Jia and S.K. Xu,2016Zhang, H., X.H. Liu, X.W. Wang, M.J. Yang, D.J. Xing, W.H. Yao and J.L. Wu,2019