kavitha issac - Academia.edu (original) (raw)

Papers by kavitha issac

Materials Today: Proceedings, 2022

2017 International Conference on Technological Advancements in Power and Energy ( TAP Energy), 2017

A switched-inductor semi-quadratic buck converter is a modification of two-switch semi-quadratic ... more A switched-inductor semi-quadratic buck converter is a modification of two-switch semi-quadratic fifth-order buck converter which belongs to the minimum-phase family. An L — switching structure is combined with the semi-quadratic buck converter in order to get high voltage conversion ratio. Moreover, it gives more bucking than the semi-quadratic buck converter. The superiority of the proposed converter is mainly based on less energy stored in the inductors. The current stress in the switching elements is less, which results in lower conduction losses. Salient performance features like voltage bucking, switching stress, inductor current etc. of proposed converter is compared with that of a semi-quadratic buck converter. In this work, simulations of both the buck topologies are presented and these are done using MATLAB/Simulink software. A prototype of 5W, 20 kHz switched-inductor semi-quadratic buck converter is designed, analysed and implemented using PIC16F877A.

In an inversion system, high reliability is one of the main targets pursuing. Some problems will ... more In an inversion system, high reliability is one of the main targets pursuing. Some problems will threaten the reliability of the system, such as, the shoot through issue and the failure of reverse recovery. The dual buck inverters can solve the above problems without adding dead time. A new topology of dual buck inverter with series connected diodes and a single inductor is presented here. The system retains the advantage of no reverse recovery of body diode. The inverter has just one filter inductor, which can make the volume and weight of the system decreased observably and improve the integration. By providing soft switching techniques the power loss can be well reduced. A resonant circuit contributes to reduced switching loss by providing ZVS property. The whole system is simulated in PSIM environment. This inverter retains the advantage of high reliability. A PIC microcontroller is used to generate control pulses since it is fast and easy to implement program when we compare wi...

In this paper, a new single phase dual output ac-dc bridgeless double boost SEPIC (IDBS) converte... more In this paper, a new single phase dual output ac-dc bridgeless double boost SEPIC (IDBS) converter is proposed which is a high step up converter. The absence of bridge rectifier in the proposed rectifier and the conduction of one semiconductor switch in the current flowing path during each switching cycle result in less conduction losses and improves efficiency. The proposed topology is designed to operate to achieve nearly a unity power factor and low total harmonic distortion (THD) of the input current. The DCM operation gives advantages such as zero-current turn-on in the power switches and simple control circuitry. The proposed topology gives better performance than modified bridgeless SEPIC rectifier in terms of efficiency, total harmonic distortion (THD), and power factor.. A design example for a 500-W/600 V dc with 120 V input voltage is provided. The proposed circuit is simulated in Matlab 2010a which ensures the feasibility of the converter

Non-acoustic self-noise observed in towed sonar arrays represents a serious problem for acoustic ... more Non-acoustic self-noise observed in towed sonar arrays represents a serious problem for acoustic source detection at low frequency. The decomposition of an array snapshot into its constituent acoustic and non-acoustic components is accomplished using a frequency-wavenumber, or F-K transform. Frequency-wavenumber diagrams can be used in order to differentiate between acoustic and non-acoustic noise. The frequency wavenumber transform is a double Fourier transform, both in time and in space, where the positive time frequencies are plotted along the y axis and the x axis represent the spatial frequency k. The acoustic energy is confined within the V-area of the F-K diagrams. Energy outside this V will highlight non-acoustic energy. From the f-k spectrum, target detection is possible using the principle of line detection by Hough transform. The Hough transform (HT), named after Paul Hough who patented the method in 1962, is a powerful global method for finding lines in an image. It tran...

International Journal of Advanced Research in Electrical, Electronics and Instrumentation Energy, 2014

Switched-mode power-supply (SMPS) converters find use in a wide variety of applications, ranging ... more Switched-mode power-supply (SMPS) converters find use in a wide variety of applications, ranging from a fraction of a milli watt in on-chip power management to hundreds of megawatts in power systems. In this paper, a multiple output dc-dc converter based on Two Switch Forward Topology is designed and developed. The power module consists of a converter which delivers constant voltage outputs frominput battery supply. Converter works in closed loop mode with necessary compensation circuits to meet the output regulation requirements for change in load. Loop Feedback is closed by make use of control winding. Input output isolation is met using gate drive transformers. The multiple output dc-dc converter is designed and investigated by using ICAP/4 using PWM controller UC1825. The simulation results have demonstrated that the proposed converter delivers constant voltage outputs with high reliability.

Energy shortages and increasing oil prices have created the demand for high energy conversion eff... more Energy shortages and increasing oil prices have created the demand for high energy conversion efficiency and performance. This paper presents a high efficient loaded resonant converter with feedback for dcdc energy conversion applications. This paper deeply analyses the converter configuration and MATLAB simulation results and compare with conventional converter topologies. The proposed converter consists of a half-bridge Inductor Capacitor Inductor resonant inverter and a load which is connected across the bridge rectifier. The output stage is filtered by a loss pass filter which is minimize the loading effect and ensure that the voltage across it is almost constant. The soft switching concepts used in this converter helps to reduce the switching losses ,EMI and increase reliability and makes the circuit simple by reducing the size and weight of components.. MATLAB software is used to simulate the model. The feedback circuit provides accurate output with an energy conversion effici...

A new non isolated multi input multi output dc–dc boost converter is pesented in this paper. This... more A new non isolated multi input multi output dc–dc boost converter is pesented in this paper. This converter is applicable in hybridizing alternative energy sources in electric vehicles. By hybridization of energy sources, advantages of different sources can be achieved. In this converter, the loads power can be flexibly distributed between input sources. Also, charging or discharging of energy storages by other input sources can be controlled properly. The proposed converter has several outputs with different voltage levels which makes it suitable for interfacing to multilevel inverters. Use of a multilevel inverter leads to reduction of voltage harmonics which, consequently, reduces torque ripple of electric motor in electric vehicles. Also, electric vehicles which uses dc motor have at least two different dc voltage levels, one for ventilation system and cabin lightening and other for supplying electric motor. The converter presented here has just one inductor. Depending on chargi...

Abstract-A novel topology for a non-isolated bidirectional DC-DC converter is presented here with... more Abstract-A novel topology for a non-isolated bidirectional DC-DC converter is presented here with softswitching capability, it usually operates at a zero-voltage-switching (ZVS) condition. In this circuit additional auxiliary circuit added for obtaining soft switching condition instead of adding auxiliary switches. The suggested auxiliary circuit consists of one resonant inductor and two capacitors. Soft-switching technology is to reduce switching losses. By generating and keeping a recycle current in the auxiliary circuits, this topology can provide soft-switching conditions for both switches. Due to the existence of the auxiliary circuits, it can reduce the current ripple in the main inductor. Here no auxiliary switches are used and also two main switches work in ZVS conditions. Main characteristic of this topology is not only operated with soft switching method but has simple structure and high efficiency. The modified converter simulated using MATLAB/SIMULINK R2014a software. Th...

International Journal of Advanced Research in Electrical, Electronics and Instrumentation Energy, 2014

The Z-source inverter (ZSI) employs an LC impedance network between thepower source andinverterbr... more The Z-source inverter (ZSI) employs an LC impedance network between thepower source andinverterbridge. The unique feature of the ZSI is that it can operateeither in buck or boost mode with a wide range of obtainableoutput voltages from a given input voltage. The Z-source inverter alsoexhibits better electromagneticinterference noise immunity whencompared to a traditional voltage-source inverter (VSI). Switched boost inverter (SBI) which is derived from Z source inverter exhibits similar advantages of ZSI with lower number of passive components and more number of active components. By utilizing the shoot through capability of switched boost inverter we can use SBI as a substitute for single switch in the boost converter. Thus SBI provide the AC output power and boost converter provide the DC output power. DC output voltage can be varied from 280V to 160V and AC output voltage can be varied from 140V to 85V with input DC source of 100V.The value of D can be varied from 0 to 0.5. The s...

A single-phase series-resonant soft-switched ac chopper without auxiliary switches with an effici... more A single-phase series-resonant soft-switched ac chopper without auxiliary switches with an efficient control circuit is presented. Basic working principle is series-resonant conversion without any cycloconversion action. Auxiliary switches are absent in this topology. The presented single-phase ac chopper is producing the resonant voltage robes by the action of series resonator with the help of four bidirectional switches. A series of sinusoidal amplitude quasi-sinusoidal pulses synthesized and present at the output as purely sinusoidal waveform following the input voltage waveform. Frequency modulation with a constant-on time control technique is used in this proposed system. Waveform syntheses for the output sinusoidal voltage are clearly explained with waveforms. A typical design example of single-phase soft-switching ac chopper is simulated to assess the system performance. The power efficiency is improved by using soft switching techniques. The total harmonic distortion is well...

Journal of emerging technologies and innovative research, 2018

A bidirectional DC-DC converter is a key device for interfacing an energy storage element with a ... more A bidirectional DC-DC converter is a key device for interfacing an energy storage element with a motor. The voltage of a storage battery is typically 60V or lower, while the voltage of the motor is 24V. Thus, a bidirectional DC-DC converter with a wide voltage-gain range is desired for energy storage systems to connect a high-voltage battery with a low voltage motor. The interleaved switched-capacitor DC-DC converter is used to interface battery with the BLDC motor. The main components used are converter, battery, motor and an inverter. The interleaved structure is adopted in the low-voltage side of this converter to reduce the ripple of the current through the low voltage side, and the series-connected structure is adopted in the high-voltage side to achieve the high step-up/step-down voltage gain and the efficiency of the converter is improved. The converter is used to perform regenerative braking of BLDC motor. Converters HV side is connected to a battery and LV side connected to...

Alternate energy sources such as solar array, fuel cell (FC), wind etc. have a wide voltage chang... more Alternate energy sources such as solar array, fuel cell (FC), wind etc. have a wide voltage change range due to the nature of the sources. The traditional converters cannot cope with this wide voltage change nature and often requires additional voltage boost by additional dc/dc converter. In this paper a double input dc-dc converter based on Z-source converters is developed. Here, the input dc voltage can be bucked or boosted and also input dc sources can deliver power to the load individually/simultaneously, so a combination of battery with one of the alternate energy sources such as solar array, wind turbine or fuel cell can be used as input sources. Various stages of double input Z-source dc-dc converter are investigated and analysed using MATLAB/Simulink. Finally, the experimental results are presented to confirm the theoretical analysis. Index Termsmulti input converter (MIC), Z-source converter, dc-dc converter. I.

One of the most common problems in signal processing is the direction of arrival (DOA) estimation... more One of the most common problems in signal processing is the direction of arrival (DOA) estimation. DOA estimator is essentially a beamformer used in conjunction with an array of sensors that collect spatial samples of propagating wave field to provide a versatile form of spatial filtering. This paper involves implementation and comparison of the time domain (conventional), and Minimum Variance Distortionless Response (MVDR) beamforming techniques, for sonar application. The performance of these beamformer in the presence of uncorrelated noise in the sensor output, based on Beam width, Side lobe level, Bearing discrimination is evaluated. MVDR involves optimizing the beamformer response so that the output contains minimum contribution due to the noise and the signal from direction other than the direction of interest.

Extremely high duty cycle of boost converter may result in higher conduction losses. To achieve a... more Extremely high duty cycle of boost converter may result in higher conduction losses. To achieve a high conversion ratio without operating at extremely high duty ratio, some converters based on transformers or coupled inductors or tapped inductors have been provided. However, the leakage inductance in the transformer, coupled inductor or tapped inductor will cause high voltage spikes in the switches and reduce system efficiency. A novel single switch cascaded dc-dc converter of boost and buck boost converters have extended voltage conversion ratio to d/(1-d)2. The features of the converter are high voltage gain; only one switch for realizing the converter, the number of magnetic components is small etc. So comparing with other topologies cascaded converter is more effective. Simulation of the converter for a dc input voltage and fixed duty cycle was done, and the same was verified experimentally for a low input voltage. The software used for simulation was MatlabR2014a.

Materials Today: Proceedings, 2022

2017 International Conference on Technological Advancements in Power and Energy ( TAP Energy), 2017

A switched-inductor semi-quadratic buck converter is a modification of two-switch semi-quadratic ... more A switched-inductor semi-quadratic buck converter is a modification of two-switch semi-quadratic fifth-order buck converter which belongs to the minimum-phase family. An L — switching structure is combined with the semi-quadratic buck converter in order to get high voltage conversion ratio. Moreover, it gives more bucking than the semi-quadratic buck converter. The superiority of the proposed converter is mainly based on less energy stored in the inductors. The current stress in the switching elements is less, which results in lower conduction losses. Salient performance features like voltage bucking, switching stress, inductor current etc. of proposed converter is compared with that of a semi-quadratic buck converter. In this work, simulations of both the buck topologies are presented and these are done using MATLAB/Simulink software. A prototype of 5W, 20 kHz switched-inductor semi-quadratic buck converter is designed, analysed and implemented using PIC16F877A.

In an inversion system, high reliability is one of the main targets pursuing. Some problems will ... more In an inversion system, high reliability is one of the main targets pursuing. Some problems will threaten the reliability of the system, such as, the shoot through issue and the failure of reverse recovery. The dual buck inverters can solve the above problems without adding dead time. A new topology of dual buck inverter with series connected diodes and a single inductor is presented here. The system retains the advantage of no reverse recovery of body diode. The inverter has just one filter inductor, which can make the volume and weight of the system decreased observably and improve the integration. By providing soft switching techniques the power loss can be well reduced. A resonant circuit contributes to reduced switching loss by providing ZVS property. The whole system is simulated in PSIM environment. This inverter retains the advantage of high reliability. A PIC microcontroller is used to generate control pulses since it is fast and easy to implement program when we compare wi...

In this paper, a new single phase dual output ac-dc bridgeless double boost SEPIC (IDBS) converte... more In this paper, a new single phase dual output ac-dc bridgeless double boost SEPIC (IDBS) converter is proposed which is a high step up converter. The absence of bridge rectifier in the proposed rectifier and the conduction of one semiconductor switch in the current flowing path during each switching cycle result in less conduction losses and improves efficiency. The proposed topology is designed to operate to achieve nearly a unity power factor and low total harmonic distortion (THD) of the input current. The DCM operation gives advantages such as zero-current turn-on in the power switches and simple control circuitry. The proposed topology gives better performance than modified bridgeless SEPIC rectifier in terms of efficiency, total harmonic distortion (THD), and power factor.. A design example for a 500-W/600 V dc with 120 V input voltage is provided. The proposed circuit is simulated in Matlab 2010a which ensures the feasibility of the converter

Non-acoustic self-noise observed in towed sonar arrays represents a serious problem for acoustic ... more Non-acoustic self-noise observed in towed sonar arrays represents a serious problem for acoustic source detection at low frequency. The decomposition of an array snapshot into its constituent acoustic and non-acoustic components is accomplished using a frequency-wavenumber, or F-K transform. Frequency-wavenumber diagrams can be used in order to differentiate between acoustic and non-acoustic noise. The frequency wavenumber transform is a double Fourier transform, both in time and in space, where the positive time frequencies are plotted along the y axis and the x axis represent the spatial frequency k. The acoustic energy is confined within the V-area of the F-K diagrams. Energy outside this V will highlight non-acoustic energy. From the f-k spectrum, target detection is possible using the principle of line detection by Hough transform. The Hough transform (HT), named after Paul Hough who patented the method in 1962, is a powerful global method for finding lines in an image. It tran...

International Journal of Advanced Research in Electrical, Electronics and Instrumentation Energy, 2014

Switched-mode power-supply (SMPS) converters find use in a wide variety of applications, ranging ... more Switched-mode power-supply (SMPS) converters find use in a wide variety of applications, ranging from a fraction of a milli watt in on-chip power management to hundreds of megawatts in power systems. In this paper, a multiple output dc-dc converter based on Two Switch Forward Topology is designed and developed. The power module consists of a converter which delivers constant voltage outputs frominput battery supply. Converter works in closed loop mode with necessary compensation circuits to meet the output regulation requirements for change in load. Loop Feedback is closed by make use of control winding. Input output isolation is met using gate drive transformers. The multiple output dc-dc converter is designed and investigated by using ICAP/4 using PWM controller UC1825. The simulation results have demonstrated that the proposed converter delivers constant voltage outputs with high reliability.

Energy shortages and increasing oil prices have created the demand for high energy conversion eff... more Energy shortages and increasing oil prices have created the demand for high energy conversion efficiency and performance. This paper presents a high efficient loaded resonant converter with feedback for dcdc energy conversion applications. This paper deeply analyses the converter configuration and MATLAB simulation results and compare with conventional converter topologies. The proposed converter consists of a half-bridge Inductor Capacitor Inductor resonant inverter and a load which is connected across the bridge rectifier. The output stage is filtered by a loss pass filter which is minimize the loading effect and ensure that the voltage across it is almost constant. The soft switching concepts used in this converter helps to reduce the switching losses ,EMI and increase reliability and makes the circuit simple by reducing the size and weight of components.. MATLAB software is used to simulate the model. The feedback circuit provides accurate output with an energy conversion effici...

A new non isolated multi input multi output dc–dc boost converter is pesented in this paper. This... more A new non isolated multi input multi output dc–dc boost converter is pesented in this paper. This converter is applicable in hybridizing alternative energy sources in electric vehicles. By hybridization of energy sources, advantages of different sources can be achieved. In this converter, the loads power can be flexibly distributed between input sources. Also, charging or discharging of energy storages by other input sources can be controlled properly. The proposed converter has several outputs with different voltage levels which makes it suitable for interfacing to multilevel inverters. Use of a multilevel inverter leads to reduction of voltage harmonics which, consequently, reduces torque ripple of electric motor in electric vehicles. Also, electric vehicles which uses dc motor have at least two different dc voltage levels, one for ventilation system and cabin lightening and other for supplying electric motor. The converter presented here has just one inductor. Depending on chargi...

Abstract-A novel topology for a non-isolated bidirectional DC-DC converter is presented here with... more Abstract-A novel topology for a non-isolated bidirectional DC-DC converter is presented here with softswitching capability, it usually operates at a zero-voltage-switching (ZVS) condition. In this circuit additional auxiliary circuit added for obtaining soft switching condition instead of adding auxiliary switches. The suggested auxiliary circuit consists of one resonant inductor and two capacitors. Soft-switching technology is to reduce switching losses. By generating and keeping a recycle current in the auxiliary circuits, this topology can provide soft-switching conditions for both switches. Due to the existence of the auxiliary circuits, it can reduce the current ripple in the main inductor. Here no auxiliary switches are used and also two main switches work in ZVS conditions. Main characteristic of this topology is not only operated with soft switching method but has simple structure and high efficiency. The modified converter simulated using MATLAB/SIMULINK R2014a software. Th...

International Journal of Advanced Research in Electrical, Electronics and Instrumentation Energy, 2014

The Z-source inverter (ZSI) employs an LC impedance network between thepower source andinverterbr... more The Z-source inverter (ZSI) employs an LC impedance network between thepower source andinverterbridge. The unique feature of the ZSI is that it can operateeither in buck or boost mode with a wide range of obtainableoutput voltages from a given input voltage. The Z-source inverter alsoexhibits better electromagneticinterference noise immunity whencompared to a traditional voltage-source inverter (VSI). Switched boost inverter (SBI) which is derived from Z source inverter exhibits similar advantages of ZSI with lower number of passive components and more number of active components. By utilizing the shoot through capability of switched boost inverter we can use SBI as a substitute for single switch in the boost converter. Thus SBI provide the AC output power and boost converter provide the DC output power. DC output voltage can be varied from 280V to 160V and AC output voltage can be varied from 140V to 85V with input DC source of 100V.The value of D can be varied from 0 to 0.5. The s...

A single-phase series-resonant soft-switched ac chopper without auxiliary switches with an effici... more A single-phase series-resonant soft-switched ac chopper without auxiliary switches with an efficient control circuit is presented. Basic working principle is series-resonant conversion without any cycloconversion action. Auxiliary switches are absent in this topology. The presented single-phase ac chopper is producing the resonant voltage robes by the action of series resonator with the help of four bidirectional switches. A series of sinusoidal amplitude quasi-sinusoidal pulses synthesized and present at the output as purely sinusoidal waveform following the input voltage waveform. Frequency modulation with a constant-on time control technique is used in this proposed system. Waveform syntheses for the output sinusoidal voltage are clearly explained with waveforms. A typical design example of single-phase soft-switching ac chopper is simulated to assess the system performance. The power efficiency is improved by using soft switching techniques. The total harmonic distortion is well...

Journal of emerging technologies and innovative research, 2018

A bidirectional DC-DC converter is a key device for interfacing an energy storage element with a ... more A bidirectional DC-DC converter is a key device for interfacing an energy storage element with a motor. The voltage of a storage battery is typically 60V or lower, while the voltage of the motor is 24V. Thus, a bidirectional DC-DC converter with a wide voltage-gain range is desired for energy storage systems to connect a high-voltage battery with a low voltage motor. The interleaved switched-capacitor DC-DC converter is used to interface battery with the BLDC motor. The main components used are converter, battery, motor and an inverter. The interleaved structure is adopted in the low-voltage side of this converter to reduce the ripple of the current through the low voltage side, and the series-connected structure is adopted in the high-voltage side to achieve the high step-up/step-down voltage gain and the efficiency of the converter is improved. The converter is used to perform regenerative braking of BLDC motor. Converters HV side is connected to a battery and LV side connected to...

Alternate energy sources such as solar array, fuel cell (FC), wind etc. have a wide voltage chang... more Alternate energy sources such as solar array, fuel cell (FC), wind etc. have a wide voltage change range due to the nature of the sources. The traditional converters cannot cope with this wide voltage change nature and often requires additional voltage boost by additional dc/dc converter. In this paper a double input dc-dc converter based on Z-source converters is developed. Here, the input dc voltage can be bucked or boosted and also input dc sources can deliver power to the load individually/simultaneously, so a combination of battery with one of the alternate energy sources such as solar array, wind turbine or fuel cell can be used as input sources. Various stages of double input Z-source dc-dc converter are investigated and analysed using MATLAB/Simulink. Finally, the experimental results are presented to confirm the theoretical analysis. Index Termsmulti input converter (MIC), Z-source converter, dc-dc converter. I.

One of the most common problems in signal processing is the direction of arrival (DOA) estimation... more One of the most common problems in signal processing is the direction of arrival (DOA) estimation. DOA estimator is essentially a beamformer used in conjunction with an array of sensors that collect spatial samples of propagating wave field to provide a versatile form of spatial filtering. This paper involves implementation and comparison of the time domain (conventional), and Minimum Variance Distortionless Response (MVDR) beamforming techniques, for sonar application. The performance of these beamformer in the presence of uncorrelated noise in the sensor output, based on Beam width, Side lobe level, Bearing discrimination is evaluated. MVDR involves optimizing the beamformer response so that the output contains minimum contribution due to the noise and the signal from direction other than the direction of interest.

Extremely high duty cycle of boost converter may result in higher conduction losses. To achieve a... more Extremely high duty cycle of boost converter may result in higher conduction losses. To achieve a high conversion ratio without operating at extremely high duty ratio, some converters based on transformers or coupled inductors or tapped inductors have been provided. However, the leakage inductance in the transformer, coupled inductor or tapped inductor will cause high voltage spikes in the switches and reduce system efficiency. A novel single switch cascaded dc-dc converter of boost and buck boost converters have extended voltage conversion ratio to d/(1-d)2. The features of the converter are high voltage gain; only one switch for realizing the converter, the number of magnetic components is small etc. So comparing with other topologies cascaded converter is more effective. Simulation of the converter for a dc input voltage and fixed duty cycle was done, and the same was verified experimentally for a low input voltage. The software used for simulation was MatlabR2014a.