In this paper,new SVPWM switching sequences for six-phase asymmetrical induction motor drives are derived with the aim to reduce inverter’s switching losses.Total three switching sequences are introduced in this pape...In this paper,new SVPWM switching sequences for six-phase asymmetrical induction motor drives are derived with the aim to reduce inverter’s switching losses.Total three switching sequences are introduced in this paper.These sequences are derived such that the phases get continuously clamped when a current of the phases is around its peak magnitude and hence reduced switching losses are recorded.The comparative performances of these modulation techniques are studied with two existing switching sequences.Simulation,analytical and experimental results are presented.Based on these results,it is found that new switching sequences reduce switching losses effectively in dual three phase inverters.展开更多
Background:Globally,80%people use plant-derived products for treating or preventing diseases.One prevalent perception about medicinal plants is that they are safe and devoid of adverse effects.However,approximately 1,...Background:Globally,80%people use plant-derived products for treating or preventing diseases.One prevalent perception about medicinal plants is that they are safe and devoid of adverse effects.However,approximately 1,50,000 plants contain toxic substances.Objective:The present review focuses on medicinal plant extracts/fractions toxicity assessments made in preclin-ical models by oral route.Methods:Detail studies were searched from databases including PubMed and Google Scholar.A manual reference screening of the selected studies was done to identify relevant articles,with no language restriction being imposed at the time of searching.Results:The studies included were performed in rodents,and the test substances were administered orally.Our search revealed 33 widely used plants or products with significant toxicity,and phytochemicals from these plants have been summarized.Through a systematic review,we identified a plethora of medicinal plant extracts reporting safety and toxicity concerns.Conclusion:In the future,preclinical toxicokinetic studies of herbs and the determination of their no-observed-adverse-effect levels are required for a complete safety assessment.Finally,the interaction of herbs with com-monly used/over-the-counter drugs in terms of the latter’s metabolic profile should be undertaken.展开更多
An on-board charger for efficiently charging multiple battery-operated electric vehicles(EVs)is introduced.It has evolved as a single-input dual-output(SIDO)integrated boost-single ended primary inductor converter(SEP...An on-board charger for efficiently charging multiple battery-operated electric vehicles(EVs)is introduced.It has evolved as a single-input dual-output(SIDO)integrated boost-single ended primary inductor converter(SEPIC)fly-back converter,offering cost-effectiveness,reliability,and higher efficiency compared to conventional chargers with equivalent specifications.The proposed system includes an additional regulated output terminal,in addition to an existing terminal for charging the EV battery of a 4-wheeler,which can be used to charge another EV battery,preferably a 2-wheeler.With the aid of control techniques,unity power factor operations are obtained during constant-voltage(CV)/constant-current(CC)charging for the grid-to-vehicle(G2V)operating mode.Using mathematical modelling analysis,the proposed system is developed in a Matlab/Simulink environment,and the results are validated in a real-time simulator using dSPACE-1104.The proposed system is employed for charging the batteries of two EVs with capacities of 400 V,40 A·h and 48 V,52 A·h for the 4-wheeler and 2-wheeler,respectively.Its performance is investigated under different operating modes and over a wide range of supply voltage variations to ensure safe and reliable operation of the charger.展开更多
In this study,a six-phase induction asymmetric induction motor(SPAIM)was examined,whose performance surpasses that of its three-phase counterpart,with regard to the torque density,torque pulsation,fault tolerance,powe...In this study,a six-phase induction asymmetric induction motor(SPAIM)was examined,whose performance surpasses that of its three-phase counterpart,with regard to the torque density,torque pulsation,fault tolerance,power rating per inverter lag,and noise characteristics.Speed-encoder-less direct torque control(DTC)for SPAIM with virtual voltage vectors(VVVs)and a modified sliding mode observer(MSMO)are described.The SPAIM model was developed using a stationaryα-βframe for DTC.The conventional DTC of the SPAIM drive is a simple extension of DTC for a 3-Φmotor drive that yields higher distortion in the stator currents.To mitigate the large amount of distortion in the stator current,VVVs were used to significantly reduce the harmonic content in the stator currents.Furthermore,to overcome the large amount of chattering observed in the case of a traditional sliding mode observer,particularly under low-speed operation,the MSMO was employed to reduce chattering even under low-speed operation.The performance of the proposed observer was verified under all the operating conditions suitable for the propulsion mode of an electric vehicle using Matlab/Simulink,and the results were experimentally validated.展开更多
A robust iteration-dependent least mean square(RIDLMS)algorithm-based fundamental extractor is developed to estimate the fundamental components of the load current for a four-wire DSTATCOM with a nonlinear load.The av...A robust iteration-dependent least mean square(RIDLMS)algorithm-based fundamental extractor is developed to estimate the fundamental components of the load current for a four-wire DSTATCOM with a nonlinear load.The averaging parameter for calculating the variable step size is iteration dependent and uses variable tuning parameters.Rather than using the current value,the previous learning rate was used in this method to achieve a more adaptive solution.This additional control factor aids in determining the exact learning rate,resulting in reliable and convergent outcomes.Its faster convergence rate and the avoidance of local minima make it advantageous.The estimation of the PI controller gains is achieved through a self-adaptive multi-population algorithm.The adaptive change in the group number will increase exploration and exploitation.The self-adaptive nature of the algorithm was used to determine the subpopulation number needed according to the fitness value.The main advantage of this self-adaptive nature is the multi-population spread throughout the search space for a better optimal solution.The estimated gains of the PI controllers are used for the DC bus and AC terminal voltage error minimization.The RIDLMS-based control with PI gains obtained using the proposed optimization algorithm showed better power quality performance.The considered RIDLMS-supported control was demonstrated experimentally using d-SPACE-1104.展开更多
An algorithm based on a sliding-mode adaptive observer is proposed for the effective control of dynamic voltage restorers(DVRs).Three single-phase voltage source converter-based topologies are implemented for the DVR....An algorithm based on a sliding-mode adaptive observer is proposed for the effective control of dynamic voltage restorers(DVRs).Three single-phase voltage source converter-based topologies are implemented for the DVR.In this control,frequency adaption is considered for estimating the phase angle,system frequency,and fundamental component of the disturbed input voltage signals.The estimated fundamental component of the supply voltage is used to generate the DVR reference load voltage.The phase jump in the supply voltage is also considered for DVR compensation studies along with voltage sag,swell,and voltage distortions.For this purpose,the gains of the proportional integral(PI)controllers used in this control algorithm are estimated using a nature-inspired optimization approach for the desired response.A moth flame optimization algorithm is implemented for PI controller gain tuning owing to the advantage of finding the best solution by each moth’s search and updating it.Through Matlab simulation and hardware testing,the performance of the DVR with an adaptive observer is found to be satisfactory for supply voltage sag,swell,phase jump,and voltage distortions.展开更多
文摘In this paper,new SVPWM switching sequences for six-phase asymmetrical induction motor drives are derived with the aim to reduce inverter’s switching losses.Total three switching sequences are introduced in this paper.These sequences are derived such that the phases get continuously clamped when a current of the phases is around its peak magnitude and hence reduced switching losses are recorded.The comparative performances of these modulation techniques are studied with two existing switching sequences.Simulation,analytical and experimental results are presented.Based on these results,it is found that new switching sequences reduce switching losses effectively in dual three phase inverters.
文摘Background:Globally,80%people use plant-derived products for treating or preventing diseases.One prevalent perception about medicinal plants is that they are safe and devoid of adverse effects.However,approximately 1,50,000 plants contain toxic substances.Objective:The present review focuses on medicinal plant extracts/fractions toxicity assessments made in preclin-ical models by oral route.Methods:Detail studies were searched from databases including PubMed and Google Scholar.A manual reference screening of the selected studies was done to identify relevant articles,with no language restriction being imposed at the time of searching.Results:The studies included were performed in rodents,and the test substances were administered orally.Our search revealed 33 widely used plants or products with significant toxicity,and phytochemicals from these plants have been summarized.Through a systematic review,we identified a plethora of medicinal plant extracts reporting safety and toxicity concerns.Conclusion:In the future,preclinical toxicokinetic studies of herbs and the determination of their no-observed-adverse-effect levels are required for a complete safety assessment.Finally,the interaction of herbs with com-monly used/over-the-counter drugs in terms of the latter’s metabolic profile should be undertaken.
文摘An on-board charger for efficiently charging multiple battery-operated electric vehicles(EVs)is introduced.It has evolved as a single-input dual-output(SIDO)integrated boost-single ended primary inductor converter(SEPIC)fly-back converter,offering cost-effectiveness,reliability,and higher efficiency compared to conventional chargers with equivalent specifications.The proposed system includes an additional regulated output terminal,in addition to an existing terminal for charging the EV battery of a 4-wheeler,which can be used to charge another EV battery,preferably a 2-wheeler.With the aid of control techniques,unity power factor operations are obtained during constant-voltage(CV)/constant-current(CC)charging for the grid-to-vehicle(G2V)operating mode.Using mathematical modelling analysis,the proposed system is developed in a Matlab/Simulink environment,and the results are validated in a real-time simulator using dSPACE-1104.The proposed system is employed for charging the batteries of two EVs with capacities of 400 V,40 A·h and 48 V,52 A·h for the 4-wheeler and 2-wheeler,respectively.Its performance is investigated under different operating modes and over a wide range of supply voltage variations to ensure safe and reliable operation of the charger.
文摘In this study,a six-phase induction asymmetric induction motor(SPAIM)was examined,whose performance surpasses that of its three-phase counterpart,with regard to the torque density,torque pulsation,fault tolerance,power rating per inverter lag,and noise characteristics.Speed-encoder-less direct torque control(DTC)for SPAIM with virtual voltage vectors(VVVs)and a modified sliding mode observer(MSMO)are described.The SPAIM model was developed using a stationaryα-βframe for DTC.The conventional DTC of the SPAIM drive is a simple extension of DTC for a 3-Φmotor drive that yields higher distortion in the stator currents.To mitigate the large amount of distortion in the stator current,VVVs were used to significantly reduce the harmonic content in the stator currents.Furthermore,to overcome the large amount of chattering observed in the case of a traditional sliding mode observer,particularly under low-speed operation,the MSMO was employed to reduce chattering even under low-speed operation.The performance of the proposed observer was verified under all the operating conditions suitable for the propulsion mode of an electric vehicle using Matlab/Simulink,and the results were experimentally validated.
基金Supported by Science and Engineering Research Board-New Delhi Project(Extra Mural Research Funding Scheme),Grant No.SB/S3/EECE/030/2016.
文摘A robust iteration-dependent least mean square(RIDLMS)algorithm-based fundamental extractor is developed to estimate the fundamental components of the load current for a four-wire DSTATCOM with a nonlinear load.The averaging parameter for calculating the variable step size is iteration dependent and uses variable tuning parameters.Rather than using the current value,the previous learning rate was used in this method to achieve a more adaptive solution.This additional control factor aids in determining the exact learning rate,resulting in reliable and convergent outcomes.Its faster convergence rate and the avoidance of local minima make it advantageous.The estimation of the PI controller gains is achieved through a self-adaptive multi-population algorithm.The adaptive change in the group number will increase exploration and exploitation.The self-adaptive nature of the algorithm was used to determine the subpopulation number needed according to the fitness value.The main advantage of this self-adaptive nature is the multi-population spread throughout the search space for a better optimal solution.The estimated gains of the PI controllers are used for the DC bus and AC terminal voltage error minimization.The RIDLMS-based control with PI gains obtained using the proposed optimization algorithm showed better power quality performance.The considered RIDLMS-supported control was demonstrated experimentally using d-SPACE-1104.
基金Supported by Science and Engineering Research Board-New Delhi,India,Project(Extra Mural Research Funding Scheme),Grant No.No.SB/S3/EECE/030/2016.
文摘An algorithm based on a sliding-mode adaptive observer is proposed for the effective control of dynamic voltage restorers(DVRs).Three single-phase voltage source converter-based topologies are implemented for the DVR.In this control,frequency adaption is considered for estimating the phase angle,system frequency,and fundamental component of the disturbed input voltage signals.The estimated fundamental component of the supply voltage is used to generate the DVR reference load voltage.The phase jump in the supply voltage is also considered for DVR compensation studies along with voltage sag,swell,and voltage distortions.For this purpose,the gains of the proportional integral(PI)controllers used in this control algorithm are estimated using a nature-inspired optimization approach for the desired response.A moth flame optimization algorithm is implemented for PI controller gain tuning owing to the advantage of finding the best solution by each moth’s search and updating it.Through Matlab simulation and hardware testing,the performance of the DVR with an adaptive observer is found to be satisfactory for supply voltage sag,swell,phase jump,and voltage distortions.
