共查询到17条相似文献,搜索用时 140 毫秒
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提出了一种由双直流电源构成的四输入端三电平逆变器拓扑结构,并采用三次谐波注入PWM作为调制方法。该逆变器通过前级两个电源和两个Buck变换器为后级电路提供四路电平,不同状态下后级电路工作于不同的三个电平状态;前级Buck变换器可以实现对直流母线电压的调节,有较宽的工作电压范围;采用三次谐波注入PWM调制方法能实现较宽的调制范围、低开关损耗及输出电压电流较少的谐波含量。分析了不同状态下双电源四输入端三电平逆变器工作原理、控制方法,并通过Simulink仿真验证了该结构的正确性和可行性。 相似文献
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在传统矩阵变换器和多电平逆变器的基础上,提出一种新颖的多电平矩阵变换器,介绍了其拓扑结构和工作原理.多电平矩阵变换器的能量传递,是通过三相输入电压对中点电容充电到一个恒定直流电压而实现的.选择适当的控制算法和电容电压,能在变换器的两侧合成低次谐波含量小且波形近似于正弦的可控输入/输出电压.对多电平矩阵变换器进行建模和仿真,并探讨了其输出能控性. 相似文献
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Anbukumar Kavitha Govindarajan Uma 《International Journal of Control, Automation and Systems》2010,8(6):1320-1329
DC-DC converters are widely used in power electronic systems where there is a need for stabilizing a given dc voltage to a
desired value. It has been reported that DC-DC converters exhibit different non-linear phenomena including bifurcations, quasi-periodicity
and chaos under both voltage mode and current mode control schemes. In this work, current mode controlled SEPIC converter
operating in continuous conduction mode is considered and by varying the reference current Iref, the converter exhibits chaos. It has been observed that the system changes from a stable buck-like operation to an unstable
boost-like operation by varying Iref. Bifurcation diagram is plotted for control signal and capacitor voltage with Iref as bifurcation parameter. Resonant parametric perturbation control technique has been applied to suppress chaos. Effects
of phase shift and frequency mismatch are also analyzed. With phase shift, control power required for suppressing chaos has
been reduced. Also intermittent chaotic stages are suppressed with the effect of frequency mismatch at the expense of increasing
control power. The stability analysis in SEPIC converter is performed by means of discrete model and is validated through
the simulated and experimental results. 相似文献
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关于在光伏系统中SEPIC变换器效率优化问题,由于光伏系统承担并网发电和输出电压,要完成大功率点的跟踪,但是转换效率往往不高,尤其是在工作频率很高时,转换效率会明显下降。为解决上述问题,提出将软开关技术应用到SEPIC变换器中,并对零电压、零电流准谐振SEPIC变换器的工作原理进行了分析,采用谐振参数的选取,应用软开关技术减小开关损耗,可以提高SEPIC变换器的效率。在MATLAB平台上对有、无软开关的SEPIC变换器进行仿真,通过改变工作频率,对两种变换器效率进行比较。仿真结果证明软开关技术能够提高SEPIC变换器的效率,为变换器设计提供了依据。 相似文献
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设计了一种新型的采用Z源阻抗网络的谐振DC-DC变换器,可最大限度地减少变换器的开关频率范围,解决了传统串联谐振变换器在宽输入电压范围时效率退化的问题,在不损坏开关器件的情况下短期和开路,具有非常强的抗电磁干扰,可靠性大大提高.实验结果验证了变换器的性能. 相似文献
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Buck型变换器自适应有限时间降压控制算法研究 总被引:2,自引:0,他引:2
针对负载未知情况下Buck型DC-DC变换器系统, 基于有限时间控制技术和自适应控制技术, 提出了一种新的快速降压控制算法.首先, 基于时间尺度变换, 对系统的平均状态空间方程进行变换; 然后, 利用饱和有限时间控制理论设计出一类新的快速降压控制算法, 以实现输出电压在有限时间内收敛到参考电压.由于控制器设计过程中考虑了饱和约束条件, 使得变换器的占空比函数满足0到1之间的约束条件.对于负载未知情况, 设计了有限时间观测器以估计未知负载, 最终得到自适应式的有限时间控制算法.与PI控制结果进行了仿真对比, 验证了所提出的控制算法既具有快速的调节性能, 又具有较强的抗负载变化性能. 相似文献
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We propose a new controller for DC-DC converters based on particle swarm optimization (PSO). This new converter controller uses the PSO optimization method to directly control, by itself, the output voltage of a boost DC-DC converter. In order to validate and qualify the proposed converter controller, we analyzed and implemented some variants of the PSO algorithm, namely the standard PSO and the global local best PSO. The proposed converter controller was then compared with a variant of the classic PI controller with anti-windup, for different operational conditions. The three controllers compared in this work were implemented in the microcontroller TMS320F28027 by using the code composer studio from Texas Instruments. The results show that the proposed controller exhibits better behavior in terms of settling time and overshoot. Unlike most popular DC-DC converter controllers, the proposed controller does not require any sort of optimal parameter determination. 相似文献
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针对常规DC-DC变换器输出电压调整困难、反馈实现复杂、智能化程度低的问题,提出了一种新型的能够根据用户要求快速改变输出电压的DC-DC变换器,并且能够根据电源输入的电压变化情况实时调整控制参数,实现稳定的电压输出,且输出电压不受输入电压变化的影响。通过对不同负载和电源输入变化的实验验证,该DC-DC变换器具有输出电压稳定精确、纹波率小、反馈快速准确的特点,对于某些对输入电压稳定性要求高的场合有实际应用意义。 相似文献