Mahajan Sagar Bhaskar

Optimized carrier based multilevel generated modified dual three-phase open-winding inverter for medium power application

This paper presents a novel carrier based multilevel modulation for modified dual three-phase open-winding inverter applicable for low-voltage/high-current applications. A standard three-phase voltage source inverter (VSI) is connected across the open-winding of both ends of the motor. Each VSI incorporates an additional bi-directional switching device (MOSFET/IGBT) per phase and all three legs link to the neutral of two capacitors in the power circuit. An original optimal double carrier zero-shifted five-level modulation (DCZ SFM) algorithm is also presented and is used to modulate each VSI in a similar way to a 5-level multilevel inverter. The complete model based system is simulated in Matlab/PLECS softwares and set of results are presented which shows good conformity with the theoretical analysis.

Five-phase five-level open-winding/star-winding inverter drive for low-voltage/high-current applications

This paper work proposed a five-phase five-level open-/star-winding multilevel AC converter suitable for low-voltage/high-current applications. Modular converter consists of classical two-level five-phase voltage source inverter (VSI) with slight reconfiguration to serve as a multilevel converter for open-/star-winding loads. Elaborately, per phase of the VSI is built with one additional bi-directional switch (MOSFET/IGBT) and all five legs links to the neutral through two capacitors. The structure allows multilevel generation to five-level output with greater potential for fault tolerability under drive failure (open-winding) and per phase fault (open-/star-winding). Further, original optimal single carrier zero-shifted modulation (SCZSFM) algorithm is proposed and capable to modulate each VSI, which is equivalent to standard 5-level multilevel inverters. Set of results are provided based on numerical modeling with MATLAB/PLECS simulation softwares and observed behavior shown good agreement with theoretical expectations.

Hybrid Non-Isolated and Non Inverting Nx Interleaved DC-DC Multilevel Boost Converter for Renewable Energy Applications

In this paper hybrid non isolated/ non inverting Nx interleaved DC-DC multilevel Boost Converter for renewable energy applications is presented. The presented hybrid topology is derived from the conventional interleaved converter and the Nx Multilevel boost converter. In renewable energy applications, generated energy cannot be directly used at application end. In most of the cases it needs to be stepped up with DC-DC converter at operating voltage levels as per the requirement of the application. Though conventional boost converter can theoretically be used for this purpose, but obtaining such high gain implies that boost converter should operate at it its maximum duty cycle, which is not feasible due to the great variations in the output voltage caused by small variations in the duty cycle, leading the boost converter to instability and also increases the voltage stress across switches. The advantages of presenting topology of DC-DC converter are high voltage conversion, reduce ripple, low voltage stress, non inverting without utilizing the high duty and transformer. The main advantage of presented topology is more number of levels can be increased by adding capacitor and diode circuitry to increase the voltage gain without disturbing the main circuit. Moreover, the presented topology is compared with several recent high gain converters. The proposed topology is simulated in MATLAB/SIMULATION and results will verify the validity of the design and operation of the converter.

Hextuple-inverter configuration for multilevel nine-phase symmetrical open-winding converter

Hextuple-inverter configuration for multilevel nine-phase symmetrical open-winding DC converter is articulated in this work. Power modular unit consists of six classical three-phase voltage source inverters (VSI). Each VSI includes one bi-directional device (MOSFET/IGBT) per each phase and link to two capacitors for neutral connection. A modified single carrier five-level modulation (MSCFM) algorithm is developed and modulates each 2-level VSI as 5-level multilevel inverter (MLI). A set of test results is presented, which are observed from the model based developments in numerical simulation softwares (Matlab/PLECS). The results always showed good conformity with the developed theoretical background under working conditions. The proposed converter found suited for (low-voltage/high current) electric vehicles, DC tractions and ‘More-Electric Aircraft’ applications.

Dual Six-Phase Multilevel AC Drive with Single Carrier Optimized Five-Level PWM for Star-Winding Configuration

This article presents new multilevel modulation strategy based on single carrier-based pulse-width modulation for dual six-phase (twelve-phase) symmetrical/asymmetrical star-end winding converter. The four standard voltage source inverters with one bidirectional switch (MOSFET/IGBT) per phase constitute the power circuit. Further, through the two capacitor bi-directional switch link the neutral link. An algorithm-based single carrier zero-shifted five-level modulation (SCZSFM) modulates each two-level VSI as a five-level output multilevel inverter. The complete AC drive is numerically modelled in MATLAB/PLECS software and tested for predicting theoretical background.

Non-isolated Sextuple Output Hybrid Triad Converter Configurations for High Step-Up Renewable Energy Applications

This article presents a new non-isolated DC-DC sextuple output hybrid triad converter configurations for high step-up renewable energy applications. Total 8 (eight) converters configurations are obtained by combining SEPIC/SI-SEPIC, Cuk/SI-Cuk, and Boost/SI-Boost which is highly suitable for step-up renewable applications where DC-DC multi-output converters/choppers are needed; such as a solar multilevel DC-AC converter (MLI), HVDC, hybrid/electric and electric vehicles. The most important characteristics of the proposed converter configurations are (i) only one power control semiconductor switch, (ii) offer six different DC outputs with different conversion ratio, (iii) non-isolated (without transformers) Converter topologies, (iv) high voltage at the output side without using large duty cycle and (v) modular DC-DC converter structure. The simulation results are presented and it validates the practicability, functionality, and the idea of suggested sextuple output hybrid triad converter configuration.

Transistor Clamped Five-Level Inverter using Non-Inverting Double Reference Single Carrier PWM Technique for photovoltaic applications

This treatise deals with Transistor Clamped Five Level Inverter using Non-Inverting Double Reference Single Carrier PWM (NIDRSC PWM) Technique. Conventional or two level inverter have drawbacks like: i) Requirement of fast switching devices, ii) Very high dv/dt, iii) High Electromagnetic Interferences (EMI), iv) Bulky filters, v) Faster heating of switches, and vi) Not suitable for high voltage applications. Multilevel Inverters (MLIs) are engaged to conquer the drawbacks of conventional two levels inverter. MLIs generate an AC voltage using small voltage steps obtained with the help of DC supplies or capacitor banks. To design the proposed five level inverter five numbers of power control switches and eight diodes are required. The proposed inverter circuitry is investigated by using Non-Inverting Double Reference Single Carrier PWM (NIDRSC PWM) Technique in terms of harmonics content in output waveform. Under-modulation (modulation Index = 0.85), unity (modulation Index =1) and over-modulation (modulation Index = 1.25) PWM signal is obtained to drive control switches. Simulation results will confirm the functionality, design and operation of the proposed MLI and NIDRSC PWM Technique.

Electric field analysis of extra high voltage (EHV) underground cables using finite element method

Transmission and Distribution of electric power through underground cables is a viable alternative to overhead lines, particularly in residential or highly populated areas. The electrical stresses are consequences of regular voltages and over voltages and the thermal stresses are related to heat produced inside the conductor due to flow of high rated current which is the main factors that affect its reliability. The performance of these underground power cables is important for proper operation of the power system. Long-term problems with them are related to the degradation of polymer materials used for the insulator due electrical, thermal or environmental stress. Most of these problems are related to the electric field stress on the insulation of the underground cables. The objective of the electric field analysis by using different numerical techniques is to find electric field stress and other parameters, which are an inevitable tool in various electricity concerned technologies; in particular for analyzing discharge phenomenon and designing Extra High Voltage (EHV) underground cables. In this paper Finite Element Method (FEM) numerical method has been discussed and used to find 2-D electric field stress and other parameters of EHV underground cables with given boundary conditions using 2-D electric field analysis software package (IES-ELECTRO module) which is based on the finite element method (FEM).

On the structural implementation of magnetic levitation windmill

In this article structural implementation and optimum performance of Vertical Axis Wind Turbine (VAWT) using magnetic levitation technology is articulated. With the positivity of customary VAWT, the surplus advantages like spinning at low wind-speed, higher efficiency, low noise emission, etc. are also quantified. The leading result ascending before traditional wind turbine can be demarcated as energy dissipation during rotation. By means of property of permanent magnet as an alternate of ball bearings, levitation of the turbine is anticipated with decline in damages while rotation and hence wind turbine blades are positioned on a shaft for attaining stability throughout rotation. Power is then generated with an axial flux generator, which incorporates the utilization of permanent magnets and set of coils.

A high gain modified SEPIC DC-to-DC boost converter for renewable energy application

The proposed work present the modified high gain Single Ended Primary Inductance Converter (SEPIC) for renewable energy applications. The voltage gain of proposed converter is very highly related to conventional dc-to-dc converter and recently projected converter based on conventional converter. The key feature of projected converter is only one controlled device and voltage gain is increased without using a transformer and coupled inductor structure. The voltage gain of projected converter is increased by 10 times compared to the SEPIC converter by adding one extra inductor and capacitor in SEPIC converter for a duty ratio of 90%. The detailed analysis of the voltage gain with the voltage drop across passive device and working of projected converter is deliberated in details in the paper. The projected converter is simulated in Matrix Laboratory software (2014). The simulation results validate the feasibility of projected converter.