Three-Stage 18 level Hybrid Cascaded Multilevel Inverter using a Hybrid Method
Malgireddy Ravi1, Palarapu Sravan Kumar2, Devireddy Sathish3
1Malgireddy Ravi, Department of Electrical Engineering, Technical Manager, Bluevega Solutions Pvt. Ltd, Hyderabad (Telangana), India.
2Palarapu Sravan Kumar, Sr. Assistant Professor, Department of Electrical Engineering, Aurora’s Scientific Technological & Research Academy, Hyderabad (Telangana), India.
3Devireddy Sathish, Assistant Professor, Department of Electrical Engineering, Abit, Paloncha, (Telangana), India.
Manuscript received on 10 May 2013 | Revised Manuscript received on 18 May 2013 | Manuscript Published on 30 May 2013 | PP: 25-30 | Volume-2 Issue-6, May 2013 | Retrieval Number: F0760052613/13©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: This paper proposes a new hybrid algorithm for three stage 18 level cascaded multilevel inverter. The inverter consists of main high-voltage, medium-voltage and low-voltage stages connected in series from the output The high-voltage stage is made of a three-phase conventional inverter to reduce dc source cost and losses. The medium- and low voltage stages are made of three-level inverters constructed using cascaded H-bridge units. The aim of the proposed algorithm is to avoid the undesirable high switching frequency for high and medium-voltage stages despite the fact that the inverter’s dc sources are selected to maximize the inverter levels by eliminating redundant voltage states. Switching algorithms of the high- and medium-voltage stages have been developed to assure fundamental switching frequency operation of the high-voltage stages and not more than few times this frequency for the medium-voltage stage. The low-voltage stage is controlled using SVM to achieve the reference voltage vector exactly and to set the order of dominant harmonics as desired. The realization of this control approach has been enabled by considering the vector space plane in the state selection rather than individual phase levels. The simulation results shows the effectiveness of the proposed strategy in terms of computational efficiency as well as the capability of the inverter to produce very low distorted voltage with low switching losses.This paper proposes a new hybrid algorithm for three stage 18 level cascaded multilevel inverter. The inverter consists of main high-voltage, medium-voltage and low-voltage stages connected in series from the output The high-voltage stage is made of a three-phase conventional inverter to reduce dc source cost and losses. The medium- and low voltage stages are made of three-level inverters constructed using cascaded H-bridge units. The aim of the proposed algorithm is to avoid the undesirable high switching frequency for high and medium-voltage stages despite the fact that the inverter’s dc sources are selected to maximize the inverter levels by eliminating redundant voltage states. Switching algorithms of the high- and medium-voltage stages have been developed to assure fundamental switching frequency operation of the high-voltage stages and not more than few times this frequency for the medium-voltage stage. The low-voltage stage is controlled using SVM to achieve the reference voltage vector exactly and to set the order of dominant harmonics as desired. The realization of this control approach has been enabled by considering the vector space plane in the state selection rather than individual phase levels. The simulation results shows the effectiveness of the proposed strategy in terms of computational efficiency as well as the capability of the inverter to produce very low distorted voltage with low switching losses.
Keywords: Inverters, Harmonics, Pulse Width Modulation (PWM), Space Vector Modulation (SVM).
Scope of the Article: Encryption Methods and Tools