Rakesh E

Bio: Rakesh E is an academic researcher from VIT University. The author has contributed to research in topics: Inverter & Pulse-width modulation. The author has an hindex of 3, co-authored 5 publications receiving 19 citations.

Identification of optimal SVPWM technique for diode clamped multilevel inverter based induction motor drive

Abstract: Multilevel inverters (MLI) are employed mainly to enhance the performance of the drive scheme which generally demands a quality power source. The modulation technique involved plays a vital role in its improvement. The conventional sine pulse width modulation (SPWM) scheme employed in this regard though suffers from various limitations resulting in drives with lesser efficiency. Hence Space Vector Pulse Width Modulation (SVPWM) techniques are becoming popular in inverter systems due to its advantages in better utilization of input voltage, lesser harmonic content and better output voltage profile, especially from the drive system point of view. The disadvantage being the complex computations involved. This paper envisages to identify the optimal SVPWM technique for diode clamped MLI. The conventional SVPWM and the proposed SVPWM techniques are applied to the diode clamped MLI fed induction motor drive. The performance of both the drive schemes are analyzed and compared, to show the effectiveness of the proposed method. The added advantage of the proposed technique is that it involves lesser computations and has generalization capability.

EMI mitigation in closed loop boost converter using soft switching combined with chaotic mapping

Abstract: The degrading performance of high frequency DC-DC converters due to Electro Magnetic Interference (EMI) must be encountered utterly. Use of chaotic PWM is an effective way to reduce the EMI, by which the entire energy can be completely spread out uniformly over the frequency band. Since, the generation of chaotic carrier in practical cases is comparatively difficult, here in this work, chaotic mapping is incorporated to convert the periodic saw tooth carrier into chaotic one. The primary sources of EMI such as di/dt and dv/dt due to rapid switching were controlled significantly by the soft switching technique which is combined with chaotic PWM to suppress electromagnetic interference. This combined approach also results in reduced switching losses and hence ameliorates the efficiency of the boost converter.

Space vector pulse width modulation for a seven level inverter applied to an induction motor drive

Abstract: Recent evolution in power electronics and semiconductor switching devices has paved the way for amelioration of various power electronic systems. Hence, various multilevel inverter configurations have been put forward with reduced device count and increased output levels. Pulses with modulated (PWM) adjustable speed drives are employed in various industrial drive applications to achieve superior performance. Among which Sinusoidal PWM (SPWM) and Space Vector PWM (SVPWM) techniques are stands out. Space vector techniques are becoming common in industrial drive applications due to its improved harmonic profile and better DC bus utilization. This paper envisages to analyze and identify an optimal modulation technique for a reduced switch seven level MLI running an induction motor drive in closed loop through Indirect Field Oriented Control (IFOC). The SPWM and the SVPWM techniques are applied to a seven MLI fed induction motor drive. The performance of both systems is analyzed and compared using MATLAB/simulink tool.

Hardware realization and analysis of a seven level reduced switch inverter with space vector modulation technique

Abstract: Multilevel inverters (MLI) are employed to enhance the performance of the motor drives, in which the performance improvement is depends on the modulation scheme and the number of power switches and associated components of MLI. Various limitations of conventional sinusoidal pulse width modulation (SPWM) technique result in drives with lesser efficiency. Space Vector Pulse Width Modulation (SVPWM) schemes are now becoming common in inverter systems due to its advantages over other techniques such as better utilization of input voltage and lesser total harmonic distortion especially from the drive system perspective. The disadvantage being the complex computations which increases with the number of voltages levels in MLI. This paper investigates and compares the performance of a seven level inverter with conventional SPWM and a new multilevel multiphase SVPWM algorithm. The model is simulated in MATLAB/simulink and a low power prototype of the model is implemented in the laboratory to verify the simulation results.

SVPWM Technique for Diode Clamped Multilevel Inverter based Induction Motor Drive

Abstract: Multilevel inverters (MLI) are employed mainly to enhance the performance of the drive scheme which generally demands a quality power source. The modulation technique involved plays a vital role in its improvement. The conventional sine pulse width modulation (SPWM) scheme employed in this regard though suffers from various limitations resulting in drives with lesser efficiency. Hence Space Vector Pulse Width Modulation (SVPWM) techniques are becoming popular in inverter systems due to its advantages in better utilization of input voltage, lesser harmonic content and better output voltage profile, especially from the drive system point of view. The disadvantage being the complex computations involved. This paper envisages to identify the optimal SVPWM technique for diode clamped MLI. The conventional SVPWM and the proposed SVPWM techniques are applied to the diode clamped MLI fed induction motor drive. The performance of both the drive schemes are analyzed and compared, to show the effectiveness of the proposed method. The added advantage of the proposed technique is that it involves lesser computations and has generalization capability.

Resonant Power Converters: An Overview with Multiple Elements in the Resonant Tank Network

Abstract: Finite commutation times are associated with the concurrent occurrence of both voltageacross and current-through semiconductor switches, leading to switching power losses. To alleviate them, soft-switching techniques have been developed. Soft-switching converters can be classified into quasi-resonant and multiresonant, resonant-transition, and resonant power converters (RPCs). This article focuses on RPCs, due to their high power density and efficiency. Specifically, RPC topologies with multiple elements are described, and their input-output relationships and efficiency are illustrated. The merits and limitations of RPCs are discussed and compared. An RPC intended to charge the battery of an electric vehicle (EV) is presented, and experimental results are discussed.

A State-of-the-Art Review on Conducted Electromagnetic Interference in Non-Isolated DC to DC Converters

Abstract: One of the most challenging and interesting field in power electronics is the ability to mitigate the Electromagnetic Interference (EMI). A natural source of EMI includes the atmospheric discharge/charge phenomena and extra-terrestrial radiation. Man-made source of EMI are line radiation, auto ignition, radio frequency interference and power lines. Suppression of EMI and enhancing the Electro Magnetic Compatibility (EMC) has become essential in high frequency power electronic converters. This review article is a one stop solution for new researchers and practitioners to understand about the effects of EMI and its suppression techniques in detail.

Spectrum calculation method for a boost converter with chaotic PWM

Abstract: In this paper, an analytical calculation method of chaotic spectrum for DC-DC converters under CPWM is firstly proposed based on Fourier series. The proposed method can be employed to precisely calculate the spectrum of PWM waveforms under CPWM. Simulation and experimental results both verify the correctness of the proposed spectrum calculation method.

FPGA based Chaotic PWM combined with soft switching for effective EMI mitigation in boost converter

Abstract: Boost converter is most widely used DC-DC converter for renewable energy applications. The operation of high frequency switching DC-DC converters causes Electro Magnetic Interference (EMI), which is degrading the normal operation of the converter and other adjacent systems. Therefore power converters must comply with the Electro Magnetic Compatibility standards in order to ensure the proper operation of converters and not to pollute the nearby systems. This paper discusses an integrated conducted EMI suppression approach, the chaotic soft switching technique based on Field Programmable Gate Array (FPGA) technology to provide a significant EMI noise attenuation in solar fed DC-DC boost converter. The solar fed DCDC boost converter is designed, simulated and implemented in hardware. The results obtained and the FFT analysis are strongly substantiate the proposed approach. The obtained results also compared with the traditional DC-DC boost converter results. The proposed system may replace the bulky passive EMI filters wherein which the space is the major concern.