Abstract—This paper proposes a parallel-connected inverter control method for material micromachining. The proposed control method is composed of a sigmoid sliding mode function (SSMF) and a firefly algorithm (FA). The SSMF is insensitive to system uncertainties, thus achieving high-quality AC output voltage. However, as the load of the micromachining (MM) is a step change situation, steady-state errors still exist in SSMF. The steady-state errors cause heat losses in transistors and high voltage harmonics in inverter output, and thus the stability and reliability of the MM are degraded. To attenuate steady-state errors, the control gains of the SSMF can be tuned via the FA. Using the proposed control method, the parallel-connected inverter yields a high-quality AC output voltage with low voltage harmonics and fast dynamic response. Experiments prove the applicability of the proposed control method in material MM. Since the proposed control method is easier to implement than previous control methods and allows high-precision tracking, this paper will be of interest to designers of correlative material micromachining.
Index Terms—Parallel-connected inverter, material micromachining, sigmoid sliding mode function (SSMF), firefly algorithm (FA), steady-state errors.
En-Chih Chang and Rong-Ching Wu are with the Department of Electrical Engineering, I-Shou University, No.1, Sec. 1, Syuecheng Rd., Dashu District, Kaohsiung City 84001, Taiwan, R.O.C. (e-mail: enchihchang@isu.edu.tw, rcwu@isu.edu.tw).
Hongshu Huang and Wei Liu are with the Electrical Engineering and Automation, Guangzhou University, Guangzhou 510006, P.R.C. (e-mail: hhs1550@163.com, 13822109999@139.com).
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Cite: En-Chih Chang, Hongshu Huang, Wei Liu, and Rong-Ching Wu, "Parallel-Connected Inverter Control Method in Material Micromachining," International Journal of Materials, Mechanics and Manufacturing vol. 6, no. 3, pp. 220-223, 2018.