Conference Papers
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Item An improved power quality converter for three-phase switched mode power supplies(IEEE Computer Society help@computer.org, 2014) Kalpana, R.; Singh, B.; Bhuvaneswari, G.In this paper, an improved power quality converter is presented for harmonic mitigation in SMPS (Switched Mode Power Supply) for telecom power applications with reduced kVA rating. The proposed ac-dc converter is found capable of suppressing less than 23rd harmonic in the supply current along with the power factor improvement close to unity in the wide operating range. The effect of load variation on the SMPS is studied to demonstrate the performance and effectiveness of the improved converter. © 2014 IEEE.Item High-efficiency improved 12kW switched mode telecom rectifier(Institute of Electrical and Electronics Engineers Inc., 2016) P, P.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.In this paper an improved switched mode telecom rectifier for a 12kW telecommunication system is presented. An improved telecom rectifier is a combination of phase-shift transformer based ac-dc converter and passive high pass filter. The phase-shift transformer and high pass filter is realized with a fractional magnetic rating of the load. The supply current is almost sinusoidal with low total harmonic distortion, and the power factor (PF) is close to unity. The complete design of phase-shift transformer based ac-dc converter and passive high pass filter is presented in this paper. The 12kW telecom rectifier is designed, modeled and simulated to reduce the total harmonic distortion (THD) of the input ac mains current and to improve the power factor. A laboratory prototype of phase-shift transformer based ac-dc converter is developed and the results are presented to validate the design topology. © 2015 IEEE.Item Configurations of modular push-pull buck DC-DC converters for 12KW telecom SMPS and its design(Institute of Electrical and Electronics Engineers Inc., 2016) P, P.; Kalpana, R.In this paper the push-pull buck DC-DC converter topologies are presented for 12kW telecom power supply. They have some attractive features compared to boost converters such as meeting the requirement of varying controllable output dc voltage, inherent short-circuit protection, and easy control of inrush current. Their input currents can be controlled in the open loop and much wider voltage loop bandwidth can be achieved. The proposed modular converter is modeled and its various configuration performance is simulated in MATLAB environment along with SIMULINK and Sim Power System (SPS). © 2016 IEEE.Item High performance three-phase PFC rectifiers for telecom power supply(Institute of Electrical and Electronics Engineers Inc., 2016) P, P.; Kalpana, R.Generally telecom power supply requires higher efficiency from the ac input mains to the load end. So the front-end power factor correction (PFC) rectifier should show very high efficiency. In this paper, the front-end ac-dc converter having a boost type PFC rectifier which is a logical solution to the telecom applications is proposed. The Minnesota rectifier and Delta Switch rectifier are discussed for the front-end PFC converter which can be used for power quality improvement. Then the output of PFC rectifier is given to the three-phase high frequency dc-ac converter which intern drives the high frequency transformer (HFT) and produces the voltage level of 60V and 100A. These whole front-end and back-end converter configurations are classified as hybrid telecom power supply. The performance of front-end three-phase PFC rectifier with the back-end dc-dc converter configuration is simulated in the MATLAB Simulink environment and the results are presented in order to validate the design. © 2016 IEEE.Item Improvement in Harmonic Reduction of Zigzag Autoconnected Transformer Based 12-pulse Diode Bridge Rectifier by Current Injection at DC Side(Institute of Electrical and Electronics Engineers Inc., 2017) Vidyasagar, V.S.; Kalpana, R.; Singh, B.To improve the harmonic reduction ability in input line current of 12-pulse diode bridge rectifier (DBR) using zigzag autoconnected transformer with a dc side current injection technique is presented in this paper. Conventional 12-pulse rectifier does not meet the IEEE-519 standard and therefore current injection technique at dc side is used to shape the system current waveform to minimize the harmonic distortion in the input line current. The proposed configuration uses zigzag autoconnected transformer with inherent ability of blocking zero-sequence components which eliminate the requirement of zero sequence blocking transformer (ZSBT). The current injection circuit with interphase reactor (IPR) enables to alter dc current at the rectifier output which further shapes input line currents to near sinewave. The proposed configuration is designed, simulated and analyzed in MATLAB/SIMULINK. Simulation results of proposed configuration for variation in current injection and load on input line current harmonic suppression, power quality parameters are presented in this paper. © 2016 IEEE.Item High performance front-end PFC rectifier for telecom power supplies(Institute of Electrical and Electronics Engineers Inc., 2017) P, P.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.High-current low-voltage (HCLV) rectifiers are used in the telecom industries, electroplating and induction heating system. Typical power rating of these rectifiers varies from tens of kW to hundreds of MW. In this paper, a three-phase three-level boost type PWM rectifier is proposed as an active front-end PFC scheme for telecom load. The proposed active front-end PFC converter is modeled by switching cycle average model and relation between duty ratio and the dc-link capacitor voltage is derived as in terms of system input currents. Also, the switching states have been derived for the feasible converter operation. The detailed analysis of front-end PFC converter is carried out by equivalent circuit. The power quality also well improved by proposed active front-end PFC rectifiers. The experimental setup for a 12 kW active front-end PFC rectifier is developed in the laboratory to validate the MATLAB simulation results. © 2016 IEEE.Item Current injection based front-end power quality improved converter for telecom load(Institute of Electrical and Electronics Engineers Inc., 2017) P, P.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.In this paper a front-end converter having third harmonic current injection technique is used for improving input current shape as near sinusoidal. Here zig-zag transformer is used as the current injection device so that the advantages pertaining to zig-zag transformer is utilized effectively. The third harmonic current injection device along with the three-level boost converter at the output stage will increase the dc-link voltage and the current is injected through zig-zag transformer. The power quality is well improved using third harmonic current modulated front-end structure which is very well applicable to telecom load having the high current low voltage. Extensive simulation is carried out for the 12 kW load and the results are verified through experimental setup. The experimental setup is tested for reduced voltage rating and the test results are presented. © 2016 IEEE.Item Power quality improvement in front-end hybrid AC-DC converter based on current injection technique(Institute of Electrical and Electronics Engineers Inc., 2017) P, P.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.This paper highlights the power quality issues and explains the remedial measures taken by means of hybrid frontend third harmonic current injection rectifiers. Here zig-zag transformer is used as the current injection device so that the advantages pertaining to zig-zag transformer is utilized effectively. The third harmonic current injection device along with the three-level boost converter at the output stage will increase the dc-link voltage. Also, the power quality is well improved using third harmonic current modulated front-end structure which is well appropriate to medium/higher power applications. The experimental prototype of hybrid front-end PFC rectifier is developed in the laboratory to validate the MATLAB simulation results. © 2017 IEEE.Item Renewable energy sources fed dual input full-bridge DC-DC converter for battery charging applications(Institute of Electrical and Electronics Engineers Inc., 2017) Kalpana, R.; Kiran, R.This paper proposes FPGA based dual input converter (DIC) for battery charging applications of 3 kW. The proposed system gives an alternative way of fusing the sources of DC in the magnetic form, instead of combining in the DC electrical form, by the addition of magnetic flux that is produced in the transformer magnetic core that works on the principle of flux additivity. A detailed design and the operation of the proposed dual input full-bridge DC-DC converter has been completely evaluated and presented in this paper. A constant frequency phase shifted PWM switching strategy has been preferred for the generation of gate pulses using FPGA controller board. The simulation analysis of the proposed converter has been executed utilizing MATLAB Simulink environment. A prototype of 1.5 kW has been developed and hardware results are presented to validate the theoretical waveform of the proposed dual input full-bridge DC-DC converter. © 2017 IEEE.Item Design and Implementation of Sensorless Voltage Control of Front-End Rectifier for Power Quality Improvement in Telecom System(Institute of Electrical and Electronics Engineers Inc., 2018) P, P.S.; Kalpana, R.; Singh, B.; Bhuvaneswari, G.In this paper, a three-phase three-switch three-level boost (Vienna) type pulse-width modulation rectifier is proposed as an active front-end power factor correction (PFC) rectifier for power quality improvement in telecom load. A sensorless voltage control technique is proposed and it does not rely on any input voltage information results in reliable and robust operation. A brief description on the principle of operation and the most advantageous modulation method of the proposed system are discussed. The feasible switching states are identified for the proposed active front-end converter resulting in reduced switching stress and dc ripples. A triangular carrier based control logic is applied and the input current reaches sinusoidal shape without the need of sensing the input voltage. The detailed analysis of front-end PFC converter is carried out by equivalent circuit analysis. Also, the complete loss and efficiency calculation of the converter is explicitly carried out with the help of hardware design guidelines. The performance of the proposed system and its capability of operating satisfactorily in the event of failure of one phase of the mains is verified through MATLAB Simulation, and the results obtained are presented. The experimental setup rated for 9 kW is developed in the laboratory to validate the simulation results. From the simulation and hardware results, it is observed and recorded that the power quality parameters are improved and are well within the IEEE and IEC standards. © 1972-2012 IEEE.