通过对三相12/8极开关磁阻控制系统的研究,以TMS320LF2407A为控芯片设计了36 k W开关磁阻电机的功率变换电路、过流保护电路及故障检测电路等;同时根据开关磁阻电机控制效果的要求,设计了双闭环控制调速结构,其中速度环采用分数阶PI调节...通过对三相12/8极开关磁阻控制系统的研究,以TMS320LF2407A为控芯片设计了36 k W开关磁阻电机的功率变换电路、过流保护电路及故障检测电路等;同时根据开关磁阻电机控制效果的要求,设计了双闭环控制调速结构,其中速度环采用分数阶PI调节器,并主要阐述了相电流斩波控制程序和电流调节器控制程序的设计。该系统针对硬件和软件方面的综合考虑,提高了开关磁阻电机调速系统的稳定性和可靠性。展开更多
The application areas of conventional push pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero voltage and zero current switching (ZCS)...The application areas of conventional push pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero voltage and zero current switching (ZCS) PWM push pull three level converter in which the voltage stress of switches is input voltage. With phase shifted modulation strategy, the leading switches can only realize zero voltage switching (ZVS), and the lagging switches can realize ZCS when block capacitor and block diodes are added. Using the strategy, the converter overcomes the drawbacks presented by the conventional push pull converter, such as magnetic aberration, large switch loss, and voltage spike on switches, so it can get higher efficiency, and a wider application area. The operating principle of the new converter is analyzed and verified on a 600 W, 50 kHz experimental prototype. Several zero voltage and zero current switching PWM push pull three level converters are proposed.展开更多
This article gives an overview of the main passive solutions and active techniques, based on AC switches to limit inrush currents in medium power AC-DC converters （up to 3.7 kW） for electric vehicle charging systems...This article gives an overview of the main passive solutions and active techniques, based on AC switches to limit inrush currents in medium power AC-DC converters （up to 3.7 kW） for electric vehicle charging systems. In particular, a strategy, based on SCR （silicon controlled rectifier） phase, shift control in a mixed rectifier bridge with diodes and thyristors, is proposed. The challenge is to help designers optimize the triggering delay of SCRs to both limit the peak value of inrush current spikes and optimize the charge duration of the DC-link capacitor. A mathematical model （Mathcad engineering tool） has been defined to point out, the interest of a variable triggering delay to control SCRs to meet the expectations described previously. Experimental measurements using an industrial evaluation board of the AC-DC converter demonstrate the robustness of the method.展开更多
This paper focuses on a combination of three-phase VSI （voltage source inverter） with a predictive current control to provide an optimized system for three-phase inverters that control the load current. A FS-MPC （f...This paper focuses on a combination of three-phase VSI （voltage source inverter） with a predictive current control to provide an optimized system for three-phase inverters that control the load current. A FS-MPC （finite set-model predictive control） strategy for a three-phase VSI for RES （renewable energy systems） applications is implemented. The renewable energy systems model is used in this paper to investigate the system performance when power is supplied to resistive-inductive load. With three different cases, the evaluation of the system is done. Firstly, the robustness of control strategy under variable DC-Link is done in terms of the THD （total harmonic distortion）. Secondly, with one prediction step, the system performance is tested using different sampling time, and lastly, the dynamic response of the system with step change in the amplitude of the reference is investigated. The simulations and result analyses are carried out using Matlab/Simulink to test the effectiveness and robustness of FS-MPC for two-level VSI with AC filter for resistive-inductive load supplied by a renewable energy system.展开更多
By means of the Keldysh Green's function method,we investigate the spin-polarized electron transport in a three-terminal device,which is composed of three normal metal leads and two serially-coupled quantum dots(Q...By means of the Keldysh Green's function method,we investigate the spin-polarized electron transport in a three-terminal device,which is composed of three normal metal leads and two serially-coupled quantum dots(QDs).The Rashba spin-orbit interaction(RSOI) is also considered in one of the QDs.We show that the spin-polarized charge current with arbitrary spin polarization can be obtained because of the quantum spin interference effect arising from the Rashba spin precession phase,and it can be modulated by the system parameters such as the applied external voltages,the RSOI strength,the QD levels,as well as the dot-lead coupling strengths.Moreover,a fully spin-polarized current or a pure spin current without any accompanying charge current can also be controlled to flow in the system.Our findings indicate that the proposed model can serve as an all-electrical spin device in spintronics field.展开更多
文摘通过对三相12/8极开关磁阻控制系统的研究,以TMS320LF2407A为控芯片设计了36 k W开关磁阻电机的功率变换电路、过流保护电路及故障检测电路等;同时根据开关磁阻电机控制效果的要求,设计了双闭环控制调速结构,其中速度环采用分数阶PI调节器,并主要阐述了相电流斩波控制程序和电流调节器控制程序的设计。该系统针对硬件和软件方面的综合考虑,提高了开关磁阻电机调速系统的稳定性和可靠性。
文摘The application areas of conventional push pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero voltage and zero current switching (ZCS) PWM push pull three level converter in which the voltage stress of switches is input voltage. With phase shifted modulation strategy, the leading switches can only realize zero voltage switching (ZVS), and the lagging switches can realize ZCS when block capacitor and block diodes are added. Using the strategy, the converter overcomes the drawbacks presented by the conventional push pull converter, such as magnetic aberration, large switch loss, and voltage spike on switches, so it can get higher efficiency, and a wider application area. The operating principle of the new converter is analyzed and verified on a 600 W, 50 kHz experimental prototype. Several zero voltage and zero current switching PWM push pull three level converters are proposed.
文摘This article gives an overview of the main passive solutions and active techniques, based on AC switches to limit inrush currents in medium power AC-DC converters （up to 3.7 kW） for electric vehicle charging systems. In particular, a strategy, based on SCR （silicon controlled rectifier） phase, shift control in a mixed rectifier bridge with diodes and thyristors, is proposed. The challenge is to help designers optimize the triggering delay of SCRs to both limit the peak value of inrush current spikes and optimize the charge duration of the DC-link capacitor. A mathematical model （Mathcad engineering tool） has been defined to point out, the interest of a variable triggering delay to control SCRs to meet the expectations described previously. Experimental measurements using an industrial evaluation board of the AC-DC converter demonstrate the robustness of the method.
文摘This paper focuses on a combination of three-phase VSI （voltage source inverter） with a predictive current control to provide an optimized system for three-phase inverters that control the load current. A FS-MPC （finite set-model predictive control） strategy for a three-phase VSI for RES （renewable energy systems） applications is implemented. The renewable energy systems model is used in this paper to investigate the system performance when power is supplied to resistive-inductive load. With three different cases, the evaluation of the system is done. Firstly, the robustness of control strategy under variable DC-Link is done in terms of the THD （total harmonic distortion）. Secondly, with one prediction step, the system performance is tested using different sampling time, and lastly, the dynamic response of the system with step change in the amplitude of the reference is investigated. The simulations and result analyses are carried out using Matlab/Simulink to test the effectiveness and robustness of FS-MPC for two-level VSI with AC filter for resistive-inductive load supplied by a renewable energy system.
基金Supported by National Natural Science Foundation of China under Grant Nos. 10704016,110704032,110704033Natural Science Foundation of Jiangsu Province under Grant No. BK2010416National Basic Research Project of China under Grant No. 2009CB945504
文摘By means of the Keldysh Green's function method,we investigate the spin-polarized electron transport in a three-terminal device,which is composed of three normal metal leads and two serially-coupled quantum dots(QDs).The Rashba spin-orbit interaction(RSOI) is also considered in one of the QDs.We show that the spin-polarized charge current with arbitrary spin polarization can be obtained because of the quantum spin interference effect arising from the Rashba spin precession phase,and it can be modulated by the system parameters such as the applied external voltages,the RSOI strength,the QD levels,as well as the dot-lead coupling strengths.Moreover,a fully spin-polarized current or a pure spin current without any accompanying charge current can also be controlled to flow in the system.Our findings indicate that the proposed model can serve as an all-electrical spin device in spintronics field.
