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RISS 인기검색어
- 검색키워드
- 저자 : M. Krishnakumar (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
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A New Random PWM Technique for Conducted-EMI Mitigation on Cuk Converter
Krishnakumar, C.,Muhilan, P.,Sathiskumar, M.,Sakthivel, M. The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.3
Electromagnetic Interference (EMI) is a system to system or environment to system phenomenon. The literature survey proved that the Randomized Pulse Width Modulation (RPWM) technique is a promising technique to reduce EMI. A new Constant Trailing Edge, Randomized Pulse Width Modulation (CTERPWM) technique is proposed in this paper. The effect of the proposed RPWM technique for mitigation of conducted-EMI on Cuk converter operating in Continuous Conduction Mode (CCM) is simulated and tested. In this paper, the analytical expressions for the Power Spectral Density (PSD) are derived for the proposed RPWM technique and are validated by experimental measurements. The effectiveness of the proposed RPWM technique on the mitigation of conducted-EMI is verified comparing simulation and experimental results and it is identified that both the results are almost similar with allowable experimental deviations. The comparative investigation proves that the proposed RPWM technique can mitigate and spread the dominant peaks of conducted-EMI over the complete spectrum for the Cuk converter. Based on the investigation the CTERPWM technique is recommended for adoption.
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M. Murugesan,N. Nallamuthu,R. Ranjithkumar,M. Krishnakumar,P. Devendran,K. Ramesh 대한금속·재료학회 2023 ELECTRONIC MATERIALS LETTERS Vol.19 No.1
Supercapacitors have been emerging tool with high power density in energy storage system. The energy storage capabilityof supercapacitors depends on electrochemical performance of transition metal oxide based electrode materials. Becauseof the co-existence of two metal ions and synergistic eff ects of elements, binary metal oxides, AB 2 O 4 (A or B = Ni, Co,Mo, Mn, and so on), have more active reaction sites and high electrical conductivity than other binary transition metaloxides. To improve the best electrochemical performance, cobalt manganese oxide (CoMn 2 O 4 ) is synthesized via simplehydrothermal method. The CoMn 2 O 4 rod is characterized to analyse its crystalline structure, functional group vibrations,surface morphology and elemental conformations. The electrochemical performance of CoMn 2 O 4 is analysed using cyclicvoltammetry, galvano-static charge–discharge and electrochemical impedance spectrum techniques. The cyclic voltammetryresult reveals that pseudo capacitive behaviour of CoMn 2 O 4 compound. The charge–discharge cycling stability of CoMn 2 O 4rod is analysed in 5 A g −1 up to 10,000 cycles. Asymmetric supercapacitor is fabricated using CoMn 2 O 4 || Activated Carbonwhich also obeys pseudo capacitive behaviour. The energy density is analysed as 28.7 Wh kg −1 at current density 1 mA forasymmetric supercapacitor device.
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A New Random PWM Technique for Conducted-EMI Mitigation on Cuk Converter
C. Krishnakumar,P. Muhilan,M. Sathiskumar,M. Sakthivel 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.3
Electromagnetic Interference (EMI) is a system to system or environment to system phenomenon. The literature survey proved that the Randomized Pulse Width Modulation (RPWM) technique is a promising technique to reduce EMI. A new Constant Trailing Edge, Randomized Pulse Width Modulation (CTERPWM) technique is proposed in this paper. The effect of the proposed RPWM technique for mitigation of conducted-EMI on Cuk converter operating in Continuous Conduction Mode (CCM) is simulated and tested. In this paper, the analytical expressions for the Power Spectral Density (PSD) are derived for the proposed RPWM technique and are validated by experimental measurements. The effectiveness of the proposed RPWM technique on the mitigation of conducted-EMI is verified comparing simulation and experimental results and it is identified that both the results are almost similar with allowable experimental deviations. The comparative investigation proves that the proposed RPWM technique can mitigate and spread the dominant peaks of conducted-EMI over the complete spectrum for the Cuk converter. Based on the investigation the CTERPWM technique is recommended for adoption.
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Joe M. Das,Krishnakumar Kesavapisharady,Saravanan Sadasivam,Suresh Narayanan Nair 대한척추외과학회 2017 Asian Spine Journal Vol.11 No.4
Study Design: Retrospective cohort study. Purpose: To examine the clinical profile and surgical complications in patients with spinal hemangioblastomas and to evaluate the long-term outcome in them. Overview of Literature: Although considered to be histologically benign, hemangioblastomas may cause significant neurological deficits. The proportion of spinal hemangioblastomas associated with von Hippel–Lindau (VHL) disease has been estimated be 13%–59%. Preoperative neurological function correlates with postoperative neurological status. Studies have shown no difference in outcomes between sporadic and VHL-associated spinal hemangioblastomas. Methods: This retrospective study included 14 consecutive patients treated for spinal hemangioblastomas at our institute between January 2000 and June 2013. The mean follow-up period was 5 years. Magnetic resonance imaging of the complete neuraxis was performed in all cases, and preoperative embolization was performed in two cases. Results: In total, 14 patients underwent 18 surgeries, of which 15 were for spinal hemangioblastomas. Of all the patients, 86% had motor weakness and 79% presented with sensory disturbances. Preoperative McCormick functional grades were grade I in 7 (50%), grade II in 3 (21%), and grade III in 4 (29%) patients; 50% patients were diagnosed with VHL disease. All patients underwent complete resection of the tumor. Eight patients experienced deterioration in their neurological status in the immediate postoperative period; among them, five had gradual improvement. At 5-year follow-up, 11 (78.57%) patients showed good functional outcomes. Conclusions: Microsurgical excision of spinal hemangioblastomas can cause postoperative morbidity, mainly in the form of neurological deterioration. Almost half of our patients had deterioration in the McCormick grade in the immediate postoperative period. However, a complete microsurgical excision can result in good long-term functional outcomes, as most of the immediate postoperative neurological deterioration in our patients was reversible. There was no difference in the long-term functional outcomes between sporadic and VHL-associated spinal hemangioblastomas.
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Sn loaded Au–ZnO photocatalyst for the degradation of AR 18 dye under UV-A light
A. Senthilraja,B. Krishnakumar,B. Subash,Abilio J.F.N. Sobral,M. Swaminathan,M. Shanthi 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.33 No.-
Sn–Au–ZnO was successfully synthesized by precipitation–decomposition method. The catalyst wascharacterized by XRD, FE-SEM, EDS, TEM, DRS, PL, XPS, TGA, DTA and BET surface area measurements. Sn–Au–ZnO is found to be more efficient than bare ZnO and other commercial catalysts at pH 11 for themineralization of AR 18 dye under UV-A light. The effects of operational parameters on photomineralization of AR 18 dye have been investigated. The mineralization of dye has been confirmed byCOD measurements. A possible mechanism is proposed for the degradation of AR 18 under UV-A light. The catalyst is found to be reusable
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