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Potnuru D.,GMR Institute of Technology | Chandra K.P.B.,University of Exeter | Arasaratnam I.,Apple Inc | Gu D.-W.,University of Leicester | And 2 more authors.
IET Electric Power Applications | Year: 2016

This paper presents a non-linear square-root estimation scheme for brushless DC (BLDC) motors. The cubature Kalman filter (CKF) is the main estimation tool for the presented approach. The CKF is a recently proposed estimator for highly non-linear systems and its efficacy has been verified on several applications. The square-root version of the CKF is preferred over the conventional CKF for real-time applications. Despite of having several advantages over other non-linear filters, the CKF has not yet been explored for state estimation of electric drives in the electric drives community. In this study, the authors present a square-root CKF for the speed and rotor position estimation of a highly non-linear and high fidelity BLDC motor, these estimated speed and rotor position are then fed back to control the speed of the BLDC motor. The efficacy of the presented approach for low and high reference speeds, and in the presence of parametric uncertainties, is demonstrated by real-time experiments. © The Institution of Engineering and Technology.


Kunche P.,Andhra University | Sasi Bhushan Rao G.,Andhra University | Reddy K.V.V.S.,Andhra University | Uma Maheswari R.,Vignan Institute of Information Technology
International Journal of Speech Technology | Year: 2014

A new approach to dual channel speech enhancement is proposed based on a recently introduced meta-heuristic optimization algorithm called hybrid PSOGSA. It is a novel algorithm which combines the ability of exploration in gravitational search algorithm (GSA) and the exploitation capability of particle swarm optimization (PSO) to offer a better local search process along with the social thinking. This paper aims to present such a hybrid combination as a promising and powerful technique to adaptive noise cancellation in speech enhancement and it is compared with the standard PSO (SPSO) and GSA based speech enhancement algorithms. Simulation results prove that the performance of PSOGSA is superior to SPSO and GSA algorithms, in the context of speech enhancement. © 2014, Springer Science+Business Media New York.


Prajna K.,Andhra University | Rao G.S.B.,Andhra University | Reddy K.V.V.S.,Andhra University | Maheswari R.U.,Vignan Institute of Information Technology
International Journal of Speech Technology | Year: 2014

This paper proposes novel heuristic algorithm called gravitational search algorithm (GSA) to speech enhancement. Stochastic and heuristic algorithms like particle swarm optimization (PSO) and some of its variants have been adapted to the field of speech enhancement in recent years. Although standard PSO (SPSO) finds good solutions, it suffers from the premature convergence by getting trapped into local optimum. In order to increase the diversity in search space and to improve the local searching capability, another recently developed heuristic algorithm GSA is proposed to speech enhancement in this paper. GSA is mainly constructed on the basis of law of gravity and the notion of mass interactions.The proposed algorithm is studied for real world noise condition called babble noise, at three different input SNR levels. To the best of our knowledge, there is no analysis about the intelligibility of enhanced speech using optimization techniques. In the present study, the proposed algorithm is compared with the standard PSO (SPSO) algorithm for dual channel speech enhancement, and the intelligibility analysis is also reported. Simulation results indicate that GSA-based algorithm outperforms the particle swarm optimization in adaptive noise cancellation with an improved speech quality and intelligibility. © 2014, Springer Science+Business Media New York.


Prajna K.,Andhra University | Reddy K.V.V.S.,Andhra University | Rao G.S.B.,Andhra University | Maheswari R.U.,Vignan Institute of Information Technology
International Journal of Speech Technology | Year: 2015

The present paper focuses on the suppression of background noise in speech signal by utilizing a powerful heuristic optimization algorithm called Bat algorithm (BA) for adaptive filtering in dual channel enhancement systems. Bat algorithm is a recently developed population based meta heuristic approach which is inspired by the hunting behavior of the bats. It is developed by Yang (2010). As a novel feature Bat algorithm is based on the echo location behavior of micro bats. BA uses the frequency tuning technique to increase the diversity of the solutions in the population, while at the same time it uses the automatic zooming and tries to balance the exploration and exploitation. A few studies have been carried out on the use of heuristics for ANC in speech enhancement by using standard particle swarm optimization (SPSO) and some of its variants till 2010. In order to extend these heuristic approaches to speech, accelerated particle swarm optimization (APSO) based enhancement approach has been proposed (Prajna et al. in Int J Speech Technol 17(4):341–351, 2014a; Prajna et al. in IJISA 6(4):1–10, 2014b, doi:10.5815/ijisa.2014.04.01; Prajna et al. in IEEE international conference on communications and signal processing (ICCSP), April 2014, pp 1457–1461, 2014c, doi:10.1109/ICCSP.2014.6950090). To overcome the problem of poor exploitation ability of APSO, another approach is proposed based on gravitational search algorithm (GSA) (Prajna et al. 2014a, b, c). To combine both the abilities of PSO and GSA algorithms, Hybrid PSOGSA algorithm is also proposed to ANC (Prajna et al. 2014a, b, c). To further improve the efficiency of adaptive filtering in ANC, by providing a dynamic balance between exploration and exploitation, BA is proposed to speech enhancement. This paper intends to present the Bat algorithm as an improved approach to ANC in speech enhancement when compared with that of SPSO, APSO, GSA and Hybrid PSOGSA based speech enhancement algorithms. The performance of all the algorithms is evaluated by computing four objective measures SNRI, PESQ, FAI and WSS, in two real world noise conditions Babble and Factory, at three different input SNR levels set at −10, 0 and 5 dB. Simulation results prove that BA is the most successful algorithm of all the algorithms studied in this work, to suppress the background noise more effectively. © 2015, Springer Science+Business Media New York.


Ramana P.,GMR Institute of Technology | Alice Mary K.,Vignan Institute of Information Technology | Surya Kalavathi M.,Jawaharlal Nehru Technological University | Phani Kumar M.,GMR Institute of Technology
World Academy of Science, Engineering and Technology | Year: 2011

This paper discusses two observers, which are used for the estimation of parameters of PMSM. Former one, reduced order observer, which is used to estimate the inaccessible parameters of PMSM. Later one, full order observer, which is used to estimate all the parameters of PMSM even though some of the parameters are directly available for measurement, so as to meet with the insensitivity to the parameter variation. However, the state space model contains some nonlinear terms i.e. the product of different state variables. The asymptotic state observer, which approximately reconstructs the state vector for linear systems without uncertainties, was presented by Luenberger. In this work, a modified form of such an observer is used by including a non-linear term involving the speed. So, both the observers are designed in the framework of nonlinear control; their stability and rate of convergence is discussed.


Baratam A.,Vignan Institute of Information Technology | Karlapudy A.M.,Vignan Institute of Information Technology | Munagala S.,Jawaharlal Nehru Technological University
Journal of Power Electronics | Year: 2014

This paper focuses on the analysis and compensation of thrust ripples in permanent magnet linear synchronous motors (PMLSM). The main drawback in PMLSMs is the presence of thrust ripples, which are mainly due to the interaction between the permanent magnets and armature slotted core. These thrust ripples reduce the performance of the drive system in high precision applications especially at low speeds. This paper analyzes thrust ripples using the discrete wavelet transform. These undesired thrust ripples are compensated by using an adaptive feed forward controller. It is observed that this novel controller reduces about 65 percent of the thrust ripples. An extensive simulation is performed through MATLAB and it is validated through experimental results using a d-SPACE system with a DS1104 control board. © 2014 KIPE.


Tirumala Rao P.,Vignan Institute of Information Technology | Siva Kumar P.,Vignan Institute of Information Technology | Ramesh Ch.,Vignan Institute of Engineering for Women | Madhu Babu Y.,Vignan Institute of Information Technology
2012 International Conference on Devices, Circuits and Systems, ICDCS 2012 | Year: 2012

Pulse compression technique is most widely used in Radar signal processing applications. For better pulse compression, peak signal to side lobe ratio i.e. merit factor should be as high as possible so that the unwanted clutter gets suppressed. To achieve the peaky main lobes and low side lobes, phase coded pulse compression codes are widely used. The simple phase code is obtained from the Binary phase coding. Matched filtering of biphase coded radar signals create unwanted side lobes which may mask important information. Hence the study of poly phase codes like Six phase pulse compression code is needed and the implementation techniques are carried out since the poly phase codes have low sidelobes and are better Doppler tolerant. The VLSI architectures for Phase coded Pulse compression systems described in the literature generate the pulse compression sequences with limited speed and consume more area on chip. But the real time implementation needs optimization of speed, area and power consumption. This paper concentrates on the design of an optimized model which can reduce these constraints. The proposed VLSI architecture can efficiently generate Six Phase pulse compression sequences while improving some of the parameters like area and speed when compared to previous methods. The VLSI architecture is implemented on the Field Programmable Gate Array (FPGA) as it provides the flexibility of reconfigurability and reprogrammability. © 2012 IEEE.


Kumar S.S.,Vignan Institute of Information Technology | Jyothi B.,Vignan Institute of Information Technology | Deepika K.K.,Vignan Institute of Information Technology
International Conference on Electrical, Electronics, Signals, Communication and Optimization, EESCO 2015 | Year: 2015

The Z-source inverter is a type of converter that exhibits voltage buck and voltage boost capability. This type of concept applied to all dc to ac, dc to dc, ac to dc, ac to ac power conversion whether two level or multilevel. Multi level converters offer many advantages for higher power applications. Generally in Z-source neutral point clamped inverter carrier based modulation technique is used for controlling. But in this paper presents the space vector modulation technique for controlling Z-source neutral point clamped inverter. This gives more advantages, in terms of harmonics performance and implementation. The proposed techniques are demonstrated in simulation. © 2015 IEEE.


Sankar R.S.R.,Vignan Institute of Information Technology | Prasad S.D.,Vignan Institute of Information Technology | Kumar K.S.,Vignan Institute of Information Technology
International Conference on Electrical, Electronics, Signals, Communication and Optimization, EESCO 2015 | Year: 2015

Custom Power is the application of power electronics to improve the quality of power distribution for sensitive industrial plants. Industries reporting production stops due to voltage disturbances, like short interruptions and voltage dips. Power electronics converters connected in series or shunt with the grid and equipped with energy storage can provide protection against voltage disturbances. This work focuses on the voltage source converter (VSC) connected in series with the grid for mitigation of voltage dips as well as swell. The core of this work is the dual vector current controller provide the error voltage. By using the space vector pulse width modulation (SVPWM) or pulse width modulation (PWM) we will generate the switching pulses to the voltage source converter which provide the mitigation for sag and swell The controller consists of two loops as name as voltage control and vector current control loop. In this work SVPWM is used because of their easier digital realization and better DC bus utilization. Controllable series compensation is used for power quality improvement under sag and swell. © 2015 IEEE.

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