Faculty Publications
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Item Synchronized SVPWM algorithm for overmodulation region for three-level VSI(2010) Veeranna, S.B.; Yaragatti, U.R.; Beig, A.R.Synchronization is essential for the satisfactory operation of VSI in high power applications. With proper selection of switching states it is possible to obtain synchronization and symmetry in space vector pulse width modulation (SVPWM) algorithm. A novel SVPWM based switching algorithm, which results in improved THD and increased fundamental voltage in overmodulation region by maintaining synchronization and symmetry is presented in this paper. A simple method to determine the switching sequence to achieve synchronization, quarter wave symmetry, half wave symmetry and three phase symmetry in overmodulation region is presented. The proposed algorithm is simulated and its performance in terms of the THD and magnitude of fundamental voltage of output is studied in the overmodulation region. The results show the improved performance of the proposed algorithm compared to the existing algorithms. The proposed algorithm is verified experimentally on a constant v/f three level VSI fed induction motor drive. © 2010 IEEE.Item Performance analysis of PWM strategies for cascaded H-bridge three-level inverter(2011) Veeranna, S.B.; Beig, A.R.; Yaragatti, U.R.Multilevel inverters with various pulse width modulation strategies have established their importance in high power high performance industrial applications, as they can synthesize output waveform with improved harmonic spectrum. This paper presents the performance analysis and comparison of different PWM strategies for cascaded H-bridge three-level inverter in terms of line voltage and motor current THD with their fundamental components. It is shown that harmonic loss minimized optimal-SHEPWM strategy gives better results in terms of voltage THD compared to SPWM, SVPWM and SHEPWM strategies. © 2011 IEEE.Item Architectural framework of on-board integrator: An interface for grid connected EV(Institute of Electrical and Electronics Engineers Inc., 2017) Hampannavar, S.; Likassa, K.; Ayenew, E.; Sandeep, N.; Yaragatti, U.R.Vehicle to Grid (V2G) is the concept of connecting a group of electric vehicles (EV) to the grid for power transaction. EVs can be connected to the grid through the home interface or through the chargers available at charging stations. In this paper, a single phase on-board charger with low complexity control scheme is proposed for EV power transaction. The power flow from and to the grid is processed using two stage cascaded converters consisting of a bidirectional DC-DC and DC-AC converters. The LCL filter is used as an interface between DC-AC converter and the grid to attenuate the grid current harmonics. A proportional resonant (PR) controller is employed for the control of grid current and to enable the unity power factor operation of the DC-AC converter. The setbacks associated with the conventional proportional-integral (PI) controller for single phase system is elevated by employing PR controller. Filter design guidelines and the control strategy developed for the proposed system is numerically simulated and verified with extensive simulation carried using MATLAB/SIMULINK. The results demonstrating the feasibility and viability of the proposed system are presented. © 2017 IEEE.Item A bus-clamping pulse width modulation method for a dodecagonal space vector generation scheme for 3-phase open-end winding induction motor drives(Institute of Electrical and Electronics Engineers Inc., 2017) Arumalla, R.T.; Figarado, S.Obtaining better harmonic profile at relatively lower switching frequencies is one of the key tasks in the present day power electronics world. Several pulse width modulation (PWM) techniques have been developed earlier in time, to reduce the harmonic content from the output of the inverter. Dodecagonal space vector generation scheme is one of them, which eliminates the most dominant lower order harmonics for the entire modulation range. In this paper, bus-clamping PWM technique is developed for a dodecagonal space vector structure, which is capable of reducing the switching frequency in the linear modulation range compared to conventional dodecagonal space vector technique. In order to compare the performance of the PWM schemes in terms of harmonic content, analytical expressions are derived based on the notion of stator flux ripple in the space vector domain. The results are verified by simulating and comparing the voltage harmonic distortion of the scheme with conventional dodecagonal scheme in terms of voltage weighted total harmonic distortion (VWTHD) and current total harmonic distortion (ITHD). © 2017 IEEE.Item A novel CSI-fed induction motor drive(2006) Beig, A.R.; Ranganathan, V.T.Current source inverter (CSI) fed drives are employed in high power applications. The conventional CSI drives suffer from drawbacks such as harmonic resonance, unstable operation at low speed ranges, and torque pulsation. This paper presents a novel CSI drive which overcomes all these drawbacks and results in sinusoidal motor voltage and current even with CSI switching at fundamental frequency. The proposed CSI drive uses a three-level inverter as an active filter across motor terminals replacing the bulky ac capacitors used in the conventional drive. A sensorless vector controlled CSI drive based on proposed configuration is developed. The simulation and experimental results are presented. Experimental results show that the proposed drive has stable operation even at low speeds. Comparative results show that the proposed CSI drive has improved torque ripple compared to the conventional configuration. © 2006 IEEE.Item Modified SVPWM algorithm for three level VSI with synchronized and symmetrical waveforms(2007) Beig, A.R.; Narayanan, G.; Ranganathan, V.T.The objective of the present work is to improve the output waveform of three level inverters used in high-power applications, where the switching frequency is very low. This is achieved by maintaining the synchronization, half-wave symmetry, quarter-wave symmetry, and three-phase symmetry in the pulsewidth modulation (PWM) waveforms. The principles of achieving synchronization and symmetries in terms of space vectors for three level inverters are presented. A novel synchronized space vector pulsewidth modulation (SVPWM) algorithms is proposed and verified experimentally. The experimental waveforms of the inverter output voltage and motor no load current for different operating conditions of the drive are presented. The performance measure in terms of the weighted total harmonic distortion (THD) of the line voltage is computed for the linear modulation region of the drive for the proposed algorithm and compared with that of synchronized SVPWM and synchronized sine-triangle pulsewidth modulation (SPWM) technique. The comparative results show that consideration of synchronization and symmetry results in improved THD. Another significant feature of the proposed algorithm is that the symmetry and synchronization leads to self-balancing of the direct current (dc) bus capacitor voltages over every one third cycle of the fundamental. © 2007 IEEE.Item Novel algorithm for control of a shunt active power filter based on a three-level voltage source inverter(2010) Rajashekhar, S.; Vittal, K.P.A three-level voltage source inverter is utilized to implement a shunt active power filter. SVPWM technique is used in the control circuit to generate the required gate pulses for the voltage source inverter. Principle of operation and analysis of the control circuit is presented. The proposed control algorithm ensures balance of dc bus voltages. Hence this active power filter is ideally suited for high power drives and transmission systems. The simulation results are presented and analyzed. The THD of load current is reduced to 6.47 % from 28.795 % in steady operation. © 2010 Institute of Thermomechanics AS CR.Item Synchronized symmetrical bus-clamping PWM strategies for three level inverter: Applications to low switching frequencies(2011) Veeranna, S.B.; Yaragatti, U.R.; Beig, A.R.The digital control of three-level voltage source inverter fed high power high performance ac drives has recently become a popular in industrial applications. In order to control such drives, the pulse width modulation algorithm needs to be implemented in the controller. In this paper, synchronized symmetrical bus-clamping pulse width modulation strategies are presented. These strategies have some practical advantages such as reduced average switching frequency, easy digital implementation, reduced switching losses and improved output voltage quality compared to conventional space vector pulse width modulation strategies. The operation of three level inverter in linear region is extended to overmodulation region. The performance is analyzed in terms THD and fundamental output voltage waveforms and is compared with conventional space vector PWM strategies and found that switching losses can be minimized using bus-clamping strategy compared to conventional space vector strategy. The proposed method is implemented using Motorola Power PC 8240 processor and verified on a constant v/f induction motor drive fed from IGBT based inverter. © 2011 Berkeley Electronic Press. All rights reserved.Item Space vector-based synchronised bus-clamping pulse width modulation algorithms for three-level voltage source inverter in overmodulation region(2012) Veeranna, S.B.; Yaragatti, R.Y.; Beig, A.R.The main objective of the present work is to develop space vector-based synchronised bus-clamping pulse width modulation algorithms to improve total harmonic distortion and higher DC-bus utilisation of the three-level inverter in overmodulation region. The proposed algorithms can generate synchronised pulse width modulation waveforms with all possible pulse number preserving all the waveform symmetries. The results of the proposed algorithms are evaluated and compared with conventional space vector pulse width modulation algorithm. It is shown that the proposed algorithms give improved results in terms of total harmonic distortion and DC-bus utilisation than that of conventional one in overmodulation region. The proposed method is implemented and verified experimentally on a constant v/f drive fed from insulated gate bipolar transistor (IGBT)-based voltage source inverter using Motorola power PC-based embedded controller. © 2012 The Institution of Engineering and Technology.Item Improved space vector PWM algorithm for three-level voltage source inverter in overmodulation region(Inderscience Publishers, 2013) Veeranna, S.B.; Yaragatti, U.In high power high performance AC drive industrial applications, multilevel inverters have established their importance, as they can synthesise output waveform with improved harmonic spectrum. In this paper, an improved synchronisation and symmetrical SVPWM algorithm is proposed for three-level inverter in overmodulation region for better utilisation of DC bus and to reduce harmonic distortion. The performance analysis of the proposed algorithm is compared with SHEPWM and STPWM for three-level voltage source inverter in terms of THD of line voltage and motor current along with fundamental component of the line voltage. It is shown that the proposed algorithm gives improved results compared to SHEPWM and STPWM algorithms. The algorithm is also verified experimentally on a constant v/f drive fed from IGBT-based voltage source inverter using Motorola power PC (MPC8240) based embedded controller. © 2013 Inderscience Enterprises Ltd.