Anshul Agarwal

FPGA Realization of Trapezoidal PWM for Generalized Frequency Converter

Combining concept of cyclo-converter and cyclo-inverter, a generalized frequency converter has been developed where undesirable harmonic components are minimized using nonsinusoidal carrier-based PWM, which is a trapezoidal pulsewidth modulation technique. The study begins by establishing a model of frequency converter to obtain the firing sequence for cyclo-converter and cyclo-inverter mode of operation. The converter is simulated using the well-known software Matlab and simulations results are presented for a single-phase ac supply. It has been found that, for cyclo-inverter operation, the minimum total harmonic distortion in the output voltage is found to be 4.8%, while during cyclo-converter operation it is only 2%. Simulation results are validated with the experimental results. A prototype of frequency converter is developed where a field-programmable gate array is used to generate the PWM trigger signal through Xilinx 9.2i. The results are also compared with other existing carrier-based modulation techniques.

Design of Delta-Modulated Generalized Frequency Converter

This paper proposes a novel power electronic application, which is an IGBT-based frequency converter that performs the function of both cycloconverter and cycloinverter by changing the 2-b input parameter. It finds its application in speed control of induction motor, induction heating, fluorescent lighting, ballast, high-frequency power supplies, and so many other applications. A methodology is developed to generate the trigger signals for various IGBTs used in frequency converters such that the circuit is not restricted to a particular value of output frequency but it can produce any output frequency that is an integer multiple of the input supply frequency. The output of the converter has been improved using delta-modulation technique. Hardware design is obtained using readily available ICs and other components. The trigger circuit has been tested qualitatively by observing waveforms on CRO. The operation of the proposed system has been found to be satisfactory.

Staircase modulated AC to AC converter

Stair-case modulation technique, generally applied in multilevel inverter is now applied in AC to AC converter for reducing harmonics in the output for both cyclo-inverters as well as for cyclo-converter mode. Simulation results are shown for single-phase to single-phase matrix converter configuration using SIMULINK software. A relation has been obtained between the carrier frequency and output frequency for a given number of levels in staircase to obtain high fundamental output voltage and low distortion factor. The minimum total harmonic distortion factor (THD) obtained is 4.8 % for cyclo-inverter operation while for cyclo-converter operation it is only 3.12 %.

Lithography technology for advanced devices and introduction to integrated CAD analysis for hotspot detection

Optical projection lithography has been the workhorse of the integrate circuit (IC) manufacturing industry to transfer the computer-aided design (CAD) to semiconducting material wafers. The resolution limit of the 193 nm wavelength lithography which was initially targeted for the 90 nm design rule has been further extended to realise ∼10–20 nm devices with ingenious interventions. The three-dimensional fin-shaped field-effect transistor device structure now realise the <20 nm design rule still using 193 nm projection lithography as the widely accepted solution. The extreme ultraviolet wavelength source systems are still in development and testing phases with some recent success reported, but still falling short of supporting volume production requirements. This study reviews the current trends in lithography and the associated resolution enhancement techniques with brief introduction to an integrated CAD analysis for hotspot detection.

Harmonic reduction in AC to AC converter by trapezoidal modulation technique

Trapezoidal modulation technique has been applied in AC to AC converter to reduce harmonics in the output. Both step up and step down operation of the converter has been studied for different output frequencies. Simulation results are shown for single-phase to single-phase converter configuration using the software SIMULINK. Minimum total harmonic distortion in the output has been found to be 5% for cyclo-inverter operation for a frequency range of 500 to 750 Hz. During cyclo-converter operation it reduces to 1.2% up to a frequency range of 1 Hz to 16.66 Hz which is generally recommended mode of cyclo-converter.

Design of an FPGA Based Controller for Delta Modulated Single-Phase Matrix Converters

A FPGA based delta modulated single phase matrix converter has been developed that may be used in both cyclo-converters and cyclo-inverters. This converter is ideal for variable speed electrical drives, induction heating, fluorescent lighting, ballasts and high frequency power supplies. The peripheral input-output and FPGA interfacing have been developed through Xilinx 9.2i, to generate delta modulated trigger pulses for the converter. The controller has been relieved of the time consuming computational task of PWM signal generation by implementing the method of trigger pulse generation in a FPGA by using Hardware Description Language VHDL in Xilinx. The trigger circuit has been tested qualitatively by observing various waveforms on an oscilloscope. The operation of the proposed system has been found to be satisfactory.

Implementation of space vector modulation for FPGA based frequency converter

Frequency converter may be used to control the speed of AC motors, in airline industries, induction heating, fluorescent lighting, ballast, high frequency power supplies and so on. It has a advantage of eliminating one or more intermediate converters. The use of self-commutated switches with PWM control can significantly improve the performance of frequency converter. This paper presents FPGA based space vector modulated (SVM) trigger controller applied to a frequency converter where trigger pulses are generated Hardware Description Language VHDL in Xilinx. The output waveforms have been synthesized for different value of output frequency. The trigger circuit has been tested qualitatively by observing various triggering pulses on Xilinx ISE simulator and then verified with experimental results. The operation of proposed system has been found satisfactory.

FPGA based space vector modulated trigger controller for a frequency converter

This paper proposes FPGA based space vector modulated (SVM) trigger controller that may be applied to a frequency converter used for high speed electrical drives, speed control of AC motor, induction heating, fluorescent lighting, ballast, high frequency power supplies and so on. To generate space vector pulse width modulated trigger pulses for the converter pperipheral input-output and FPGA interfacing has been developed through Xilinx 9.2i. In order to relieve the controller from the time consuming computational task of PWM signal generation, method of space vector PWM signal generation is implemented on FPGA using Hardware Description Language VHDL in Xilinx. Simulated results are shown on ISE-Simulator and they are found to be satisfactory.

Fully-depleted ultra narrow (-10 nm) body Gate-All-Around CMOS transistors

Device structures such as double-gate Fin-FET, tri-gated MOSFET, Pi-gate MOSFET and Ω-shaped FET [1-5] have attracted much attention for their ability to enhance the electrostatic control of gate over the channel. Unlike planar MOSFET, the gate on these devices controls the channel from more than one-side which suppresses the short channel effects (SCE) and improves Ion/Ioff ratio. Gate-all-around (GAA) ultra thin and/or narrow body transistor has gate control from all sides and therefore is a very important device structure for extreme CMOS scaling. The theoretical studies by Auth et al. [6], clearly show 40% enhancement in scaling using GAA structures in comparison to double gate transistors. However, due to process complexity, very few experimental results have been reported on such devices [7-11] with very limited device data, most of which are not exactly a combination of GAA and ultra narrow body channels. In this work, using alternating phase shift mask lithography and self-limiting-oxidation techniques [12], we demonstrate the fabrication of nand p-type GAA FETs on SOI with ultra narrow (~10 nm) silicon fin as the body. The devices exhibit excellent electrostatic control e.g. sub-threshold slope (SS) ~ 63 mV/dec, Ion/Ioff ~10 and drain induced barrier lowering (DIBL) ~ 40 mV/V. We report, for the first time, that GAA devices are fully immune to the substrate bias, which makes them free of soft errors and suitable candidates for radiation hardened devices. We also demonstrate that the multi-fin GAA scales up the drive current in proportion to the number of fins without loosing much on electrostatic control and therefore can be used for high performance applications.

Power control in centralized distributed AC load for wind energy system

In electrical power systems, isolated energy system is a more challenging task to fulfill the active power demand as well as reactive power demand under the fluctuating wind at different load conditions. In this paper, a centralized AC load, centralized distributed hybrid system (CDHS), is analyzed. CDHS has the following features in place of the DC centralized grid system, which is focused on controlling of a permanent magnet synchronous generator, a bi-directional DC-AC converter (BDC) with battery energy storage, and a wind energy conversion system with a single-stage, 3-phase 4-wire AC-AC converter connected to a common AC bus. Non-isolation of the input terminals, multi-stage operation, size and cost of the circuits, and efficient working of the AC-AC converter has been resolved using a 3-phase 4-wire AC-AC converter. A specific triggering pattern of variable frequencies to a constant frequency has been generated for the switching devices in the AC-AC converter to achieve a desired polarity of the ou...