针对交直流混合微电网中双向AC/DC换流器在外界扰动下出现的直流母线电压波动问题,设计了一种应用于双向AC/DC换流器的非线性扩张状态观测器(nonlinear extended state observer,NLESO),以实现对分布式电源功率波动和负荷投切变化等不...针对交直流混合微电网中双向AC/DC换流器在外界扰动下出现的直流母线电压波动问题,设计了一种应用于双向AC/DC换流器的非线性扩张状态观测器(nonlinear extended state observer,NLESO),以实现对分布式电源功率波动和负荷投切变化等不确定因素的快速追踪与补偿,保证了在不同扰动下交直流混合微电网的稳定性。进一步提出了基于NLESO的改进积分滑模控制方法,提高了直流母线电压的控制精度。结合非线性光滑函数设计了滑模趋近律,消除了传统滑模控制中的高频抖振现象。通过Lyapunov理论对系统的稳定性进行分析验证,仿真结果表明该控制方法响应速度快、控制精度高、抗扰动能力强并且无抖振现象。展开更多
文中提出一种新型单级式隔离AC-DC变换器及控制方案。所提结构在不改变图腾柱无桥功率因数校正(totem pole bridge-free power factor correction,TP-PFC)和双向全桥(dual active bridge,DAB)两级式AC-DC变换器特性的前提下,将TP-PFC高...文中提出一种新型单级式隔离AC-DC变换器及控制方案。所提结构在不改变图腾柱无桥功率因数校正(totem pole bridge-free power factor correction,TP-PFC)和双向全桥(dual active bridge,DAB)两级式AC-DC变换器特性的前提下,将TP-PFC高频桥臂和DAB原边侧第一个桥臂进行开关复用,减小了开关器件数目。同时,相较于TP-PFC和DAB两级式AC-DC变换器,取消了直流母线电解电容并且抑制了交流电感电流尖峰。利用其拓扑特点及所提出的控制方案,实现了拓扑开关器件的全范围软开关。首先详细分析所提拓扑结构的工作特性,包括工作模态、拓扑优点、功率特性及软开关特性;其次基于对拓扑的分析,提出控制简单的控制策略;最后,对所提拓扑结构及控制方案进行实验验证。展开更多
Inter-regional transmission line fault often results in power flow transferring, tie-line overloading and system islanding. Traditional control methods such asgenerator tripping and load shedding are costly, and also ...Inter-regional transmission line fault often results in power flow transferring, tie-line overloading and system islanding. Traditional control methods such asgenerator tripping and load shedding are costly, and also have undesirable impacts on theloadside. In this paper, a new emergency power control strategy is proposed for multi-channel interconnected system by using the overload capacity of non-fault DC lines. First of all, the capacity of emergency power control can be acquired by critical transmission power of a certain tie-line for stability. Secondly, the shortest electric distance can be calculated by Dijkstra algorithm, and then the priority of emergency control of the DC lines can be obtained by the entropy weight method. When the inter-regional transmission power decreases and the effect of single DC line emergency control is poor, the multi-channel cooperative emergency control strategy is proposed to ensure the system stability. Simulation results verify the effectiveness of the method proposed.展开更多
This paper presents the comparison of various current control strategies employed for an interleaved power factor correction (PFC) boost converter for improving the power quality. The major control strategies discusse...This paper presents the comparison of various current control strategies employed for an interleaved power factor correction (PFC) boost converter for improving the power quality. The major control strategies discussed in this paper are: peak current control, average current control, hysteresis control, borderline current control and non-linear control. These strategies are implemented in MATLAB/SIMULINK and the performance of the proposed converter is compared under open loop and closed loop operation. From the results, the input current waveform was close to input voltage waveform implying improved power factor and reduced total harmonic distortion for nonlinear current control technique. Experimental results validate the proposed method.展开更多
文摘针对交直流混合微电网中双向AC/DC换流器在外界扰动下出现的直流母线电压波动问题,设计了一种应用于双向AC/DC换流器的非线性扩张状态观测器(nonlinear extended state observer,NLESO),以实现对分布式电源功率波动和负荷投切变化等不确定因素的快速追踪与补偿,保证了在不同扰动下交直流混合微电网的稳定性。进一步提出了基于NLESO的改进积分滑模控制方法,提高了直流母线电压的控制精度。结合非线性光滑函数设计了滑模趋近律,消除了传统滑模控制中的高频抖振现象。通过Lyapunov理论对系统的稳定性进行分析验证,仿真结果表明该控制方法响应速度快、控制精度高、抗扰动能力强并且无抖振现象。
文摘文中提出一种新型单级式隔离AC-DC变换器及控制方案。所提结构在不改变图腾柱无桥功率因数校正(totem pole bridge-free power factor correction,TP-PFC)和双向全桥(dual active bridge,DAB)两级式AC-DC变换器特性的前提下,将TP-PFC高频桥臂和DAB原边侧第一个桥臂进行开关复用,减小了开关器件数目。同时,相较于TP-PFC和DAB两级式AC-DC变换器,取消了直流母线电解电容并且抑制了交流电感电流尖峰。利用其拓扑特点及所提出的控制方案,实现了拓扑开关器件的全范围软开关。首先详细分析所提拓扑结构的工作特性,包括工作模态、拓扑优点、功率特性及软开关特性;其次基于对拓扑的分析,提出控制简单的控制策略;最后,对所提拓扑结构及控制方案进行实验验证。
文摘Inter-regional transmission line fault often results in power flow transferring, tie-line overloading and system islanding. Traditional control methods such asgenerator tripping and load shedding are costly, and also have undesirable impacts on theloadside. In this paper, a new emergency power control strategy is proposed for multi-channel interconnected system by using the overload capacity of non-fault DC lines. First of all, the capacity of emergency power control can be acquired by critical transmission power of a certain tie-line for stability. Secondly, the shortest electric distance can be calculated by Dijkstra algorithm, and then the priority of emergency control of the DC lines can be obtained by the entropy weight method. When the inter-regional transmission power decreases and the effect of single DC line emergency control is poor, the multi-channel cooperative emergency control strategy is proposed to ensure the system stability. Simulation results verify the effectiveness of the method proposed.
文摘This paper presents the comparison of various current control strategies employed for an interleaved power factor correction (PFC) boost converter for improving the power quality. The major control strategies discussed in this paper are: peak current control, average current control, hysteresis control, borderline current control and non-linear control. These strategies are implemented in MATLAB/SIMULINK and the performance of the proposed converter is compared under open loop and closed loop operation. From the results, the input current waveform was close to input voltage waveform implying improved power factor and reduced total harmonic distortion for nonlinear current control technique. Experimental results validate the proposed method.
