Kamalesh Hatua

Bio: Kamalesh Hatua is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Insulated-gate bipolar transistor & Gate driver. The author has an hindex of 21, co-authored 82 publications receiving 1516 citations. Previous affiliations of Kamalesh Hatua include Indian Institute of Science & North Carolina State University.

A Novel VSI- and CSI-Fed Dual Stator Induction Motor Drive Topology for Medium-Voltage Drive Applications

Abstract: A new configuration is proposed for high-power induction motor drives. The induction machine is provided with two three-phase stator windings with their axes in line. One winding is designed for higher voltage and is meant to handle the main (active) power. The second winding is designed for lower voltage and is meant to carry the excitation (reactive) power. The excitation winding is powered by an insulated-gate-bipolar-transistor-based voltage source inverter with an output filter. The power winding is fed by a load-commutated current source inverter. The commutation of thyristors in the load-commutated inverter (LCI) is achieved by injecting the required leading reactive power from the excitation inverter. The MMF harmonics due to the LCI current are also cancelled out by injecting a suitable compensating component from the excitation inverter, so that the electromagnetic torque of the machine is smooth. Results from a prototype drive are presented to demonstrate the concept.

Common mode filter for motor controllers

Abstract: A motor drive circuit has a converter for coupling to an AC voltage source and an inverter coupled to the converter for providing a drive current for a motor A common mode circulation loop is coupled to the converter and to the inverter, and circulates common mode current from both the converter and the inverter

A three-phase three winding topology for Dual Active Bridge and its D-Q mode control

Abstract: A new Dual Active Bridge (DAB) topology is proposed with a 15-kV SiC-IGBT based three-level inverter at the high-voltage side and 1200-V SiC-MOSFET based paralleled two-level inverter at the low-voltage side. The proposed DAB is an integral part of a solid state transformer which connects a 13.8-kV distribution grid and a 480-V utility grid. The three-level inverter connected at the high-voltage side and a pair of two-level inverters connected at the low-voltage sides (in Y/Δ) of the high frequency link transformer help to reduce dominant harmonic currents. Thus harmonic-free currents in the high frequency link transformer are achieved without pulse-width modulation. A simple control is proposed and validated with simulation results.

Control technique for 15 kV SiC IGBT based active front end converter of a 13.8 kV grid tied 100 kVA transformerless intelligent power substation

Abstract: This paper discusses the control technique adopted for a 3-Level Neutral Point Clamped (3L-NPC) converter, which is the rectifier stage of a 100 kVA solid state transformer known as the Transformerless Intelligent Power Substation (TIPS) interfacing with 138 kV grid Due to high voltage (138 kV) and low power (100 kVA) specification for the rectifier, the control technique needs to be specially designed to control very low magnitude of line current (4184 A rms) Due to dead time in the converter and harmonic voltage present in the grid, the rectifier current is rich in lower order harmonics (6m±1) Moreover due to very high grid voltage, limiting starting inrush current within the converter current rating is a serious issue A unified control technique is discussed to mitigate the above mentioned problems Also the proposed control technique addresses the grid voltage unbalance and dc bus mid-point voltage unbalance issue faced by the rectifier stage of TIPS Simulation and SiC IGBT prototype experimental results verify the proposed techniques

Medium voltage power converter design and demonstration using 15 kV SiC N-IGBTs

Abstract: This paper summarizes the different steps that have been undertaken to design medium voltage power converters using the state-of-the-art 15 kV SiC N-IGBTs. The 11 kV switching characterization results, 11 kV high dv/dt gate driver validation, and the heat-run test results of the SiC IGBT at 10 kV, 550 W/cm2 (active area) have been recently reported as individual topics. In this paper, it is attempted to link all these individual topics and present them as a complete subject from the double pulse tests to the converter design, for evaluating these novel high voltage power semiconductor devices. In addition, the demonstration results of two-level H-Bridge and three-level NPC converters, both at 10 kV dc input, are being presented for the first-time. Lastly, the performance of two-chip IGBT modules for increased current capability and demonstration of three-level poles, built using these modules, at 10 kV dc input with sine-PWM and square-PWM modulation for rectifier and dc-dc stages of a three-phase solid state transformer are presented.

Multiphase Electric Machines for Variable-Speed Applications

Abstract: Although the concept of variable-speed drives, based on utilization of multiphase machines, dates back to the late 1960s, it was not until the mid- to late 1990s that multiphase drives became serious contenders for various applications. These include electric ship propulsion, locomotive traction, electric and hybrid electric vehicles, ldquomore-electricrdquo aircraft, and high-power industrial applications. As a consequence, there has been a substantial increase in the interest for such drive systems worldwide, resulting in a huge volume of work published during the last ten years. An attempt is made in this paper to provide a brief review of the current state of the art in the area. After addressing the reasons for potential use of multiphase rather than three-phase drives and the available approaches to multiphase machine designs, various control schemes are surveyed. This is followed by a discussion of the multiphase voltage source inverter control. Various possibilities for the use of additional degrees of freedom that exist in multiphase machines are further elaborated. Finally, multiphase machine applications in electric energy generation are addressed.

Multiphase induction motor drives - : a technology status review

Abstract: The area of multiphase variable-speed motor drives in general and multiphase induction motor drives in particular has experienced a substantial growth since the beginning of this century. Research has been conducted worldwide and numerous interesting developments have been reported in the literature. An attempt is made to provide a detailed overview of the current state-of-the-art in this area. The elaborated aspects include advantages of multiphase induction machines, modelling of multiphase induction machines, basic vector control and direct torque control schemes and PWM control of multiphase voltage source inverters. The authors also provide a detailed survey of the control strategies for five-phase and asymmetrical six-phase induction motor drives, as well as an overview of the approaches to the design of fault tolerant strategies for post-fault drive operation, and a discussion of multiphase multi-motor drives with single inverter supply. Experimental results, collected from various multiphase induction motor drive laboratory rigs, are also included to facilitate the understanding of the drive operation.

Design Of Analog Cmos Integrated Circuits

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Review of Solid-State Transformer Technologies and Their Application in Power Distribution Systems

Abstract: The solid-state transformer (SST), which has been regarded as one of the 10 most emerging technologies by Massachusetts Institute of Technology (MIT) Technology Review in 2010, has gained increasing importance in the future power distribution system. This paper presents a systematical technology review essential for the development and application of SST in the distribution system. The state-of-the-art technologies of four critical areas are reviewed, including high-voltage power devices, high-power and high-frequency transformers, ac/ac converter topologies, and applications of SST in the distribution system. In addition, future research directions are presented. It is concluded that the SST is an emerging technology for the future distribution system.

Capacitor-Current-Feedback Active Damping With Reduced Computation Delay for Improving Robustness of LCL-Type Grid-Connected Inverter

Abstract: This paper investigates the capacitor-current-feedback active damping for the digitally controlled LCL-type grid-connected inverter. It turns out that proportional feedback of the capacitor current is equivalent to virtual impedance connected in parallel with the filter capacitor due to the computation and pulse width modulation (PWM) delays. The LCL-filter resonance frequency is changed by this virtual impedance. If the actual resonance frequency is higher than one-sixth of the sampling frequency (fs/6), where the virtual impedance contains a negative resistor component, a pair of open-loop unstable poles will be generated. As a result, the LCL-type grid-connected inverter becomes much easier to be unstable if the resonance frequency is moved closer to fs/6 due to the variation of grid impedance. To address this issue, this paper proposes a capacitor-current-feedback active damping with reduced computation delay, which is achieved by shifting the capacitor current sampling instant towards the PWM reference update instant. With this method, the virtual impedance exhibits more like a resistor in a wider frequency range, and the open-loop unstable poles are removed; thus, high robustness against the grid-impedance variation is acquired. Experimental results from a 6-kW prototype confirm the theoretical expectations.