Dimmers are very widely applied in theatres,cinemas,dancing-parties, auditoriums and signal systems.They are usually supplied by single-stage AC/AC converters in the past with voltage regulation technique with the dis...Dimmers are very widely applied in theatres,cinemas,dancing-parties, auditoriums and signal systems.They are usually supplied by single-stage AC/AC converters in the past with voltage regulation technique with the disadvantages of high total harmonic distortion,low power factor and poor power transfer efficiency.This paper introduces a novel method-DC-modulation that implements DC/DC conversion technology into AC/AC converters.The DC-modulated single-stage PFC AC/AC converters effectively improved the power factor up to 0.999 and the power transfer efficiency up to 97.8 %.The experimental results verified our design and calculation.This technique will be widely used in light dimming and other industrial applications.展开更多
Mathematical modelling for power DC/DC converters is a historical problem accompanying DC/DC conversion technology since 1940’s. The traditional mathematical modelling is not available for complex structure converter...Mathematical modelling for power DC/DC converters is a historical problem accompanying DC/DC conversion technology since 1940’s. The traditional mathematical modelling is not available for complex structure converters since the differential equation order increases very high. We have to search other way to establish mathematical modelling for power DC/DC converters.We have theoretically defined a new concept-Energy Factor （EF） in this paper and researched the relations between EF and the mathematical modelling for power DC/DC converters. EF is a new concept in power DC/DC conversion technology, which thoroughly differs from the traditional concepts such as power factor （PF）, power transfer efficiency （η）, total harmonic distortion （THD） and ripple factor （RF）. EF and the subsequential EFV (and EFVD) can illustrate the system stability, reference response and interference recovery. This investigation is very helpful for system design and DC/DC converters characteristics foreseeing. Two DC/DC converters: Buck converter and Super-Lift Luo-Converter as the samples are analysed in this paper to demonstrate the applications of EF, EFV (and EFVD), PE, SE, VE （and VED）, time constant τ and damping time constant τd.展开更多
针对直流微电网中储能系统功率波动、负载侧负荷频繁投切等不确定因素引起母线电压产生波动的问题,以储能系统中三相交错并联双向DC-DC变换器为研究对象,提出一种基于级联有限时间扩张状态观测器(cascade finite-time extended state ob...针对直流微电网中储能系统功率波动、负载侧负荷频繁投切等不确定因素引起母线电压产生波动的问题,以储能系统中三相交错并联双向DC-DC变换器为研究对象,提出一种基于级联有限时间扩张状态观测器(cascade finite-time extended state observer,CFT-ESO)的微分平坦和改进型超螺旋滑模双闭环复合控制策略.首先,建立三相交错并联双向DC-DC变换器的数学模型,并根据微分平坦理论将其直流系统转化为微分平坦系统,结合两级具有快速收敛性的有限时间扩张状态观测器提高对系统集总扰动的估计精度.其次,采用内环微分平坦控制、外环改进型超螺旋滑模控制的双闭环控制系统,既能提高系统动态响应过程,又能利用高阶滑模控制算法抑制抖振,同时解决变换器升压模式中非最小相位问题.再次,通过Lyapunov理论证明控制系统的稳定性.最后,利用MATLAB/Simulink仿真软件以及搭建实验平台对控制策略进行验证,结果表明,本文所提控制策略能够很好地抵抗扰动,提高系统的暂态性能.展开更多
文摘Dimmers are very widely applied in theatres,cinemas,dancing-parties, auditoriums and signal systems.They are usually supplied by single-stage AC/AC converters in the past with voltage regulation technique with the disadvantages of high total harmonic distortion,low power factor and poor power transfer efficiency.This paper introduces a novel method-DC-modulation that implements DC/DC conversion technology into AC/AC converters.The DC-modulated single-stage PFC AC/AC converters effectively improved the power factor up to 0.999 and the power transfer efficiency up to 97.8 %.The experimental results verified our design and calculation.This technique will be widely used in light dimming and other industrial applications.
文摘Mathematical modelling for power DC/DC converters is a historical problem accompanying DC/DC conversion technology since 1940’s. The traditional mathematical modelling is not available for complex structure converters since the differential equation order increases very high. We have to search other way to establish mathematical modelling for power DC/DC converters.We have theoretically defined a new concept-Energy Factor （EF） in this paper and researched the relations between EF and the mathematical modelling for power DC/DC converters. EF is a new concept in power DC/DC conversion technology, which thoroughly differs from the traditional concepts such as power factor （PF）, power transfer efficiency （η）, total harmonic distortion （THD） and ripple factor （RF）. EF and the subsequential EFV (and EFVD) can illustrate the system stability, reference response and interference recovery. This investigation is very helpful for system design and DC/DC converters characteristics foreseeing. Two DC/DC converters: Buck converter and Super-Lift Luo-Converter as the samples are analysed in this paper to demonstrate the applications of EF, EFV (and EFVD), PE, SE, VE （and VED）, time constant τ and damping time constant τd.
文摘针对直流微电网中储能系统功率波动、负载侧负荷频繁投切等不确定因素引起母线电压产生波动的问题,以储能系统中三相交错并联双向DC-DC变换器为研究对象,提出一种基于级联有限时间扩张状态观测器(cascade finite-time extended state observer,CFT-ESO)的微分平坦和改进型超螺旋滑模双闭环复合控制策略.首先,建立三相交错并联双向DC-DC变换器的数学模型,并根据微分平坦理论将其直流系统转化为微分平坦系统,结合两级具有快速收敛性的有限时间扩张状态观测器提高对系统集总扰动的估计精度.其次,采用内环微分平坦控制、外环改进型超螺旋滑模控制的双闭环控制系统,既能提高系统动态响应过程,又能利用高阶滑模控制算法抑制抖振,同时解决变换器升压模式中非最小相位问题.再次,通过Lyapunov理论证明控制系统的稳定性.最后,利用MATLAB/Simulink仿真软件以及搭建实验平台对控制策略进行验证,结果表明,本文所提控制策略能够很好地抵抗扰动,提高系统的暂态性能.
