Shimi S.L

Bio: Shimi S.L is an academic researcher. The author has contributed to research in topics: Topology (electrical circuits) & Converters. The author has an hindex of 2, co-authored 2 publications receiving 30 citations.

Bidirectional dc to dc Converters: An Overview of Various Topologies, Switching Schemes and Control Techniques

Abstract: Bidirectional dc to dc converter is used as a key device for interfacing the storage devices between source and load in renewable energy system for continuous flow of power because the output of the renewable energy system fluctuates due to change in weather conditions. In electric vehicles also, bidirectional converter is used between energy source and motor for power supply from battery to motor. Thus, bidirectional dc to dc converters are getting more and more attention in academic research and in industrial applications. Bidirectional dc to dc converters work in both buck and boost mode and can manage the flow of power in both the direction between two dc sources and load by using specific switching scheme and phase shifted control strategy and hence generated excess energy can be stored in batteries/super capacitors. Therefore, the basic knowledge and classification of bidirectional dc to dc converters on the basis of galvanic isolation, the comparison between their voltage conversion ratio and output current ripple along with various topologies researched in recent years are presented in this paper. Finally, zero current and zero voltage soft switching schemes and phase shifted controlling techniques are also highlighted.

Modelling and Analysis of Novel Topology for Multilevel Inverter With Reduce Number of Switches

Abstract: The demand of quality power is increasing continuously. The problem of global warming and rate of decrease of non-renewable energy sources are increasing day by day. Hence renewable energy sources such as fuel cell, solar, Magneto hydro Dynamic (MHD), geothermal are the best alternatives to solve the problem of environmental issue and increasing demand of energy. The output of these resources is dc, therefore to connect these resources to the grid, multilevel inverter is the key device. But the output of multilevel inverter has power quality issues such as harmonic generation and notching due to conversion of dc to ac and high number of switch. Hence, this paper deals with harmonic elimination using Genetic Algorithm based Selective Harmonic Elimination (GA-SHE) techniques for asymmetric and symmetric topology of MLI. In the present study, comparative study among the 5-level, 7-level, 9-level, 11-level and 15-level multilevel inverters with reduced number of switches topologies has been discussed. A novel topology of 15-level inverter which consists least number of switches has been designed for a desired voltage level. Also, the comparison of Total harmonic distortion developed in the output voltage generated by different topology at different levels with the proposed 15-level inverter topology are discussed.

A comprehensive overview of the dc-dc converter-based battery charge balancing methods in electric vehicles

Abstract: With the development of electric vehicle (EV) technologies, efficient and reliable use of rechargeable batteries (RBs) has become the key subject for automotive manufacturers. Among RBs, lithium-ion battery technology is the most prominent about high specific energy and specific power. The lithium-ion battery pack consists of battery cells with low terminal voltage connected in series to meet the voltage requirement of the EV system. However, the useable capacity of the battery pack is restricted by the low charge cell among the string. The manufacturing inconsistency and different operating conditions of each cell cause the charge imbalances in the battery pack. These imbalances lead to the reduction of the useable capacity, acceleration of cell degradation, and, more importantly, serious safety hazards like overcharging. In all EVs and hybrid electric vehicles (HEVs) using lithium-ion battery systems, the cell balancing controller is an essential task which managed by the battery management system (BMS) to improve battery life cycle and safety. This paper presents a comprehensive overview of the DC-DC converter-based battery balancing system because of the impactful contribution to the charge balancing control and the design of balancing control algorithms. Moreover, other BMS functions such as state of charge (SOC) estimation, which affects balancing performance, are handled in this review.

A Review on State-of-the-Art Power Converters: Bidirectional, Resonant, Multilevel Converters and Their Derivatives

Abstract: With the rapid development of modern energy applications such as renewable energy, PV systems, electric vehicles, and smart grids, DC-DC converters have become the key component to meet strict industrial demands. More advanced converters are effective in minimizing switching losses and providing an efficient energy conversion; nonetheless, the main challenge is to provide a single converter that has all the required features to deliver efficient energy for different types of modern energy systems and energy storage system integrations. This paper reviews multilevel, bidirectional, and resonant converters with respect to their constructions, classifications, merits, demerits, combined topologies, applications, and challenges; practical recommendations were also made to deliver clear ideas of the recent challenges and limited capabilities of these three converters to guide society on improving and providing a new, efficient, and economic converter that meets the strict demands of modern energy system integrations. The needs of other industrial applications, as well as the number of used elements for size and weight reduction, were also considered to achieve a power circuit that can effectively address the identified limitations. In brief, integrated bidirectional resonant DC-DC converters and multilevel inverters are expected to be well suited and highly demanded in various applications in the near future. Due to their highlighted merits, more studies are necessary for achieving a perfect level of reducing losses and components.

Robust non-linear control of a hybrid water pumping system based on induction motor

Abstract: This contribution presents a non-linear control of a hybrid pumping system supplied with a photovoltaic generator and a battery. This system is employed for delivering a continuous volume of water whatever the climatic conditions. In the DC side, a boost converter is controlled with the indirect double integral sliding mode controller (DISMC) for maximum power point tracking (MPPT). The DISMC is suitable for MPPT because it gives a fast response and reduces the amplitude of power oscillations. Then, a bidirectional buck-boost converter is adopted to ensure the energy management between the battery and the DC-bus, and this converter is controlled with integral sliding mode control (ISMC) theory. The non-linear predictive control (NPC) is chosen to drive an induction motor (IM), the NPC is known by its fast dynamic and high capacity to reject disturbances. The hybrid system is modelled in MATLAB/Simulink software. During simulations, the DISMC-MPPT is compared with other techniques such as sliding mode controller (SMC) MPPT and integral SMC MPPT, the DISMC provides the best tracking performances under different irradiances. Moreover, the designed controller for the bidirectional converter regulates the DC-link voltage with better performances than the classical PI controller. Lastly, the NPC regulates the speed of the IM with high robustness.

Adjustable Speed Induction Motor drive fed by 13-level Cascaded Inverter and 54-Pulse Converter

Abstract: This study presents a performance evaluation of a high power induction motor drive, which is operated by a 13-level cascaded H-bridge multilevel inverter (CHB-MLI) and a 54-pulse AC-DC converter. The higher number of voltage levels to adhere the power quality standard IEEE 519 at drive end and less- number of power switches are feasible due to asymmetric DC supplies, having 1:2:3 voltage ratio. A Nearest level control switching technique is presented to minimize the pole voltage transitions for CHB-MLI, thereby diminishing the switching losses of the high power converter. A 54-pulse rectification system is presented to adhere the power quality standard IEEE519 at utility end. Simulation results demonstrate the performance of a 30kW induction motor drive in steady and dynamic states. A sensitivity study is conducted in the experimental setup with 7.5kW(10hp) to evaluate the steady and dynamic state performances of this drive system. A comprehensive study shows a superior power quality performance both at grid and drive end of the system.