混合移相控制全桥变换器的研究
发布时间：2018-12-13 11:43
【摘要】：在燃料电池发电系统中,要求前端DC/DC变换器具有适应宽范围电压变化的输入特性、提供高电压增益的输出特性、实现电气隔离的功率传输特性和宽负载范围的软开关特性。本课题依此设计要求,对混合移相控制的全桥变换器进行了研究。本文设计了一种基于新型三电平结构的全桥变换器,并加入辅助电流源电路,提高了电压增益,减小了器件应力,实现了原边开关管的宽范围软开关。应用混合移相的控制策略,即变换器工作在Boost模式时副边移相控制,工作在Buck模式时双重移相控制,拓宽了输入电压的可调节范围,消除了二极管电压尖峰。同时减小了原边环流损耗,实现了副边开关管全工作模式下的软开关,提升了变换器效率。通过对变换器各个工作模式的稳态特性分析,详细说明了输出特性、软开关特性和无功环流特性与电路相关参数的关系,为电路的参数设计和控制提供了依据。采用扩展函数描述法和降阶等效电路法建立了变换器的小信号模型,对比分析后以降阶模型设计了闭环补偿网络,使得系统具有更高的稳态精度和更快的动态响应。最后,对变换器进行仿真,验证了各个模式下工作过程和相应稳态特性分析的正确性。制作了一台输入电压40V-80V,输出电压300V,开关频率100k Hz,输出功率300W的实验样机。采用DSP作为主控制器,对数字控制部分进行了设计。实验测试结果表明:变换器能够在宽范围的输入电压下保持输出电压的稳定,并实现了原副边开关管全工作模式下的软开关,同时具有良好的动态性能,达到了预期的设计要求。
[Abstract]:In the fuel cell power generation system, the front-end DC/DC converter is required to have input characteristics that adapt to the wide range voltage variation, provide the output characteristics of high voltage gain, realize the power transmission characteristics of electrical isolation and soft switching characteristics of wide load range. According to the design requirements, this paper studies the hybrid phase-shifted full-bridge converter. In this paper, a novel three-level full-bridge converter is designed, and the auxiliary current source circuit is added to improve the voltage gain, reduce the device stress, and realize a wide range of soft switching of the primary side switch. The control strategy of mixed phase shift, that is, auxiliary side shift control when the converter works in Boost mode and double phase shift control when working in Buck mode, is applied to widen the adjustable range of input voltage and eliminate the diode voltage spike. At the same time, the loss of the primary circulation is reduced, and the soft switching of the auxiliary side switch is realized in full mode, which improves the efficiency of the converter. By analyzing the steady-state characteristics of each mode of operation of the converter, the relationship between the output characteristics, soft switching characteristics and reactive circulation characteristics and the circuit parameters is explained in detail, which provides the basis for the design and control of the circuit parameters. The small signal model of the converter is established by using the extended function description method and the reduced order equivalent circuit method. The closed-loop compensation network is designed by using the reduced order model, which makes the system have higher steady-state accuracy and faster dynamic response. Finally, the converter is simulated to verify the correctness of the operation process and the corresponding steady-state characteristic analysis in each mode. An experimental prototype with an input voltage of 40V-80V, an output voltage of 300V and a switching frequency of 100k Hz, output power of 300W is made. Using DSP as the main controller, the digital control part is designed. The experimental results show that the converter can keep the output voltage stable in a wide range of input voltages, and realize the soft switching of the primary and secondary side switches in full operation mode. At the same time, the converter has good dynamic performance. Meet the expected design requirements.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM46
，
本文编号：2376478
[Abstract]:In the fuel cell power generation system, the front-end DC/DC converter is required to have input characteristics that adapt to the wide range voltage variation, provide the output characteristics of high voltage gain, realize the power transmission characteristics of electrical isolation and soft switching characteristics of wide load range. According to the design requirements, this paper studies the hybrid phase-shifted full-bridge converter. In this paper, a novel three-level full-bridge converter is designed, and the auxiliary current source circuit is added to improve the voltage gain, reduce the device stress, and realize a wide range of soft switching of the primary side switch. The control strategy of mixed phase shift, that is, auxiliary side shift control when the converter works in Boost mode and double phase shift control when working in Buck mode, is applied to widen the adjustable range of input voltage and eliminate the diode voltage spike. At the same time, the loss of the primary circulation is reduced, and the soft switching of the auxiliary side switch is realized in full mode, which improves the efficiency of the converter. By analyzing the steady-state characteristics of each mode of operation of the converter, the relationship between the output characteristics, soft switching characteristics and reactive circulation characteristics and the circuit parameters is explained in detail, which provides the basis for the design and control of the circuit parameters. The small signal model of the converter is established by using the extended function description method and the reduced order equivalent circuit method. The closed-loop compensation network is designed by using the reduced order model, which makes the system have higher steady-state accuracy and faster dynamic response. Finally, the converter is simulated to verify the correctness of the operation process and the corresponding steady-state characteristic analysis in each mode. An experimental prototype with an input voltage of 40V-80V, an output voltage of 300V and a switching frequency of 100k Hz, output power of 300W is made. Using DSP as the main controller, the digital control part is designed. The experimental results show that the converter can keep the output voltage stable in a wide range of input voltages, and realize the soft switching of the primary and secondary side switches in full operation mode. At the same time, the converter has good dynamic performance. Meet the expected design requirements.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM46
，
本文编号：2376478
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