The 3Φinduction motor is a broadly used electric machine in industrial applications,which plays a vital role in industries because of having plenty of beneficial impacts like low cost and easiness but the problems lik...The 3Φinduction motor is a broadly used electric machine in industrial applications,which plays a vital role in industries because of having plenty of beneficial impacts like low cost and easiness but the problems like decrease in motor speed due to load,high consumption of current and high ripple occurrence of ripples have reduced its preferences.The ultimate objective of this study is to control change in motor speed due to load variations.An improved Trans Z Source Inverter(ΓZSI)with a clamping diode is employed to maintain constant input voltage,reduce ripples and voltage overshoot.To operate induction motor at rated speed,different controllers are used.The conventional Proportional-Inte-gral(PI)controller suffers from high settling time and maximum peak overshoot.To overcome these limitations,Fractional Order Proportional Integral Derivative(FOPID)controller optimized by Gray Wolf Optimization(GWO)technique is employed to provide better performance by eliminating maximum peak overshoot pro-blems.The proposed speed controller provides good dynamic response and controls the induction motor more effectively.The complete setup is implemented in MATLAB Simulation to verify the simulation results.The proposed approach provides optimal performance with high torque and speed along with less steady state error.展开更多
Induction motor is the most sought after motor in the industry for excellent performance characteristics and robustness. Developments in the Power Electronic circuitry have revolutionised the induction motor industry ...Induction motor is the most sought after motor in the industry for excellent performance characteristics and robustness. Developments in the Power Electronic circuitry have revolutionised the induction motor industry leading to the developments in various control strategies and circuits for motor control. Direct Torque Control (DTC) is one of the excellent control strategies preferred by industries for controlling the torque and flux in an induction machine. The main drawback of DTC is the presence of torque ripple which is slightly more than the acceptable limit. There are various parameters that introduce ripples in the electromagnetic torque, one of them being the type of inverter circuit. There are various types of inverter circuits available and the effect of each of them in the production of torque ripple is different. This work is an attempt to identify the influence of various multilevel inverter circuits on the torque ripple level and to propose the best inverter circuit. The influence of multilevel diode clamped inverter and cascaded H bridge inverter circuits on torque ripple minimization, is analysed using simulation studies for identifying the most suitable multilevel inverter circuit which gives minimum torque ripple. The results obtained from the simulation studies are validated by hardware implementation on 0.75 kW induction motor.展开更多
This paper presents a novel and efficient control scheme for unified power quality conditioner （UPQC） based on three-level neutral point clamped （NPC） inverter using fuzzy logic techniques. The proposed UPQC is ca...This paper presents a novel and efficient control scheme for unified power quality conditioner （UPQC） based on three-level neutral point clamped （NPC） inverter using fuzzy logic techniques. The proposed UPQC is capable of mitigating source current harmonics and compensate all voltage disturbances such as voltage sags, swells, unbalances and harmonics. It is designed by the integration of series and shunt active filters （AFs） sharing a common DC bus capacitor. The DC voltage is maintained constant using proportional integral voltage controller. The synchronous reference frame （SRF） theory is used to get the reference signals for shunt active power filters （APFs） and the power reactive theory （p-q theory） for series APFs. The shunt and series APF reference signals derived from the control algorithm and sensed signals are injected in two controllers to generate switching signals. To improve the UPQC capability, fuzzy logic techniques are introduced to control the series APF. The performances of the proposed UPQC system are evaluated in terms of power factor correction, mitigation of voltage or current harmonics and all other voltage disturbances compensation using Matlab-Simulink software and SimPowerSystem toolbox. The simulation results illustrate the performance of the proposed UPQC at the common connection point of the nonlinear load to improve the power energy quality.展开更多
提出一种基于二极管无源钳位思想的单相无变压器型光伏并网逆变器拓扑。与H5等传统电路相比,本拓扑具有更好的对地漏电流抑制能力。目前主流的单相无变压器型逆变电路普遍采用直流或交流解耦技术,阻断共模电流的流通路径。但是,功率开...提出一种基于二极管无源钳位思想的单相无变压器型光伏并网逆变器拓扑。与H5等传统电路相比,本拓扑具有更好的对地漏电流抑制能力。目前主流的单相无变压器型逆变电路普遍采用直流或交流解耦技术,阻断共模电流的流通路径。但是,功率开关上的寄生电容可能与共模电抗形成谐振回路,使得共模电流无法彻底消除。以H5拓扑为例,定量分析功率器件寄生电容影响共模电流的机理。针对这一问题,引入无源二极管钳位电路,使得共模电压被母线电容中点钳位,从而抑制了功率器件寄生电容引起的共模电压振荡,更有效地消除对地漏电流。在理论和仿真分析的基础上,通过搭建2 k W实验平台验证所提拓扑的性能。结果表明,改进拓扑相对于原拓扑而言,能更好地抑制对地漏电流,提高了无变压器型光伏并网系统的安全裕度。展开更多
针对有限控制集模型预测控制方法在多电平多相逆变器中预测模型和目标函数在线计算量大的不足,提出一种快速有限控制集模型预测控制方法。该方法根据参考矢量的空间位置,让远离参考矢量的电压矢量不参与预测模型在线计算和目标函数在线...针对有限控制集模型预测控制方法在多电平多相逆变器中预测模型和目标函数在线计算量大的不足,提出一种快速有限控制集模型预测控制方法。该方法根据参考矢量的空间位置,让远离参考矢量的电压矢量不参与预测模型在线计算和目标函数在线评估。对于三电平三相逆变器,快速有限控制集模型预测控制方法使参与计算的电压矢量由27个减少到12个,大大提高计算效率。最后,建立起5 k W二极管钳位型三电平三相逆变器实验平台。对于传统有限控制集模型预测控制和快速有限控制集模型预测控制进行对比稳态和动态实验。实验结果表明:所提出快速有限控制集模型预测控制方法使系统具有良好的静、动态性能。展开更多
文摘The 3Φinduction motor is a broadly used electric machine in industrial applications,which plays a vital role in industries because of having plenty of beneficial impacts like low cost and easiness but the problems like decrease in motor speed due to load,high consumption of current and high ripple occurrence of ripples have reduced its preferences.The ultimate objective of this study is to control change in motor speed due to load variations.An improved Trans Z Source Inverter(ΓZSI)with a clamping diode is employed to maintain constant input voltage,reduce ripples and voltage overshoot.To operate induction motor at rated speed,different controllers are used.The conventional Proportional-Inte-gral(PI)controller suffers from high settling time and maximum peak overshoot.To overcome these limitations,Fractional Order Proportional Integral Derivative(FOPID)controller optimized by Gray Wolf Optimization(GWO)technique is employed to provide better performance by eliminating maximum peak overshoot pro-blems.The proposed speed controller provides good dynamic response and controls the induction motor more effectively.The complete setup is implemented in MATLAB Simulation to verify the simulation results.The proposed approach provides optimal performance with high torque and speed along with less steady state error.
文摘Induction motor is the most sought after motor in the industry for excellent performance characteristics and robustness. Developments in the Power Electronic circuitry have revolutionised the induction motor industry leading to the developments in various control strategies and circuits for motor control. Direct Torque Control (DTC) is one of the excellent control strategies preferred by industries for controlling the torque and flux in an induction machine. The main drawback of DTC is the presence of torque ripple which is slightly more than the acceptable limit. There are various parameters that introduce ripples in the electromagnetic torque, one of them being the type of inverter circuit. There are various types of inverter circuits available and the effect of each of them in the production of torque ripple is different. This work is an attempt to identify the influence of various multilevel inverter circuits on the torque ripple level and to propose the best inverter circuit. The influence of multilevel diode clamped inverter and cascaded H bridge inverter circuits on torque ripple minimization, is analysed using simulation studies for identifying the most suitable multilevel inverter circuit which gives minimum torque ripple. The results obtained from the simulation studies are validated by hardware implementation on 0.75 kW induction motor.
文摘This paper presents a novel and efficient control scheme for unified power quality conditioner （UPQC） based on three-level neutral point clamped （NPC） inverter using fuzzy logic techniques. The proposed UPQC is capable of mitigating source current harmonics and compensate all voltage disturbances such as voltage sags, swells, unbalances and harmonics. It is designed by the integration of series and shunt active filters （AFs） sharing a common DC bus capacitor. The DC voltage is maintained constant using proportional integral voltage controller. The synchronous reference frame （SRF） theory is used to get the reference signals for shunt active power filters （APFs） and the power reactive theory （p-q theory） for series APFs. The shunt and series APF reference signals derived from the control algorithm and sensed signals are injected in two controllers to generate switching signals. To improve the UPQC capability, fuzzy logic techniques are introduced to control the series APF. The performances of the proposed UPQC system are evaluated in terms of power factor correction, mitigation of voltage or current harmonics and all other voltage disturbances compensation using Matlab-Simulink software and SimPowerSystem toolbox. The simulation results illustrate the performance of the proposed UPQC at the common connection point of the nonlinear load to improve the power energy quality.
文摘提出一种基于二极管无源钳位思想的单相无变压器型光伏并网逆变器拓扑。与H5等传统电路相比,本拓扑具有更好的对地漏电流抑制能力。目前主流的单相无变压器型逆变电路普遍采用直流或交流解耦技术,阻断共模电流的流通路径。但是,功率开关上的寄生电容可能与共模电抗形成谐振回路,使得共模电流无法彻底消除。以H5拓扑为例,定量分析功率器件寄生电容影响共模电流的机理。针对这一问题,引入无源二极管钳位电路,使得共模电压被母线电容中点钳位,从而抑制了功率器件寄生电容引起的共模电压振荡,更有效地消除对地漏电流。在理论和仿真分析的基础上,通过搭建2 k W实验平台验证所提拓扑的性能。结果表明,改进拓扑相对于原拓扑而言,能更好地抑制对地漏电流,提高了无变压器型光伏并网系统的安全裕度。
文摘针对有限控制集模型预测控制方法在多电平多相逆变器中预测模型和目标函数在线计算量大的不足,提出一种快速有限控制集模型预测控制方法。该方法根据参考矢量的空间位置,让远离参考矢量的电压矢量不参与预测模型在线计算和目标函数在线评估。对于三电平三相逆变器,快速有限控制集模型预测控制方法使参与计算的电压矢量由27个减少到12个,大大提高计算效率。最后,建立起5 k W二极管钳位型三电平三相逆变器实验平台。对于传统有限控制集模型预测控制和快速有限控制集模型预测控制进行对比稳态和动态实验。实验结果表明:所提出快速有限控制集模型预测控制方法使系统具有良好的静、动态性能。
