高功率因数单开关隔离型PFC变换器研究

发布时间：2018-03-02 02:19

本文关键词： 功率因数校正单开关隔离型正弦平方补偿谐振变导通时间　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着电力电子设备的广泛应用,AC-DC开关变换器为公共电网带来了严重的谐波污染。功率因数校正(Power Factor Correction,PFC)技术可以有效地消除电力系统的谐波污染,提高输入功率因数。因此,PFC技术在AD-DC开关变换器中得到了广泛的应用。单开关隔离型PFC变换器具有输入输出隔离、成本低、结构简单等优点而被广泛应用于PFC技术领域,其中反激PFC变换器最受欢迎。一般来说,由于变压器漏感的能量需要被RCD缓冲电路消耗,才能避免电路中出现较大的电压、电流尖峰。因此,反激PFC变换器的工作效率将因其缓冲电路而受到限制。本文致力于研究高功率因数、高效率的隔离型PFC变换器。传统峰值电流控制(Peak Current Controlled,PCC)临界连续模式(Critical Conduction Mode,CRM)反激PFC变换器的开关管电流峰值包络跟随输入正弦半波电压,导致输入电流不是标准正弦波。本文提出一种正弦平方补偿峰值电流控制(Sine Square Compensated Peak Current Controlled,S2C-PCC)方法。在PCC-CRM反激PFC变换器的开关管峰值电流包络中补偿一个正弦平方项,该项系数由输入电压幅值、输出电压和变压器原副边线圈匝比共同决定。以补偿后的峰值电流包络对开关管电流峰值进行控制,使变换器在全输入电压范围内实现单位功率因数。最后,通过仿真和实验验证了理论分析的正确性。为降低CRM反激PFC变换器中变压器漏感的能量损耗,提高变换器的工作效率,本文首次在CRM反激PFC变换器的变压器副边引入一个由谐振电容、变压器漏感以及续流二极管组成的谐振网络,将变换器漏感能量传递到负载,提高了变换器的工作效率,降低了开关管、二极管的电压应力。同时,采用定导通时间(Constant On Time,COT)控制方法,还使得变换器的输入电流变得更加正弦。最后,通过仿真和实验验证了理论分析的正确性。类似地,本文将谐振网络引入到断续模式(Discontinuous Conduction Mode,DCM)反激PFC变换器中,解决了 DCM反激PFC变换器低工作效率的问题,但也使得原有的标准正弦输入电流发生严重的畸变。因此,为了消除谐振网络给DCM反激PFC变换器带来的不利影响,本文将VOT控制方法应用到了 DCM单开关谐振隔离型PFC变换器中。通过引入输入电压和输出电压来共同调节开关管导通时间,使得VOT-DCM单开关谐振隔离型PFC变换器具有高工作效率、低器件应力的同时,还能够保持和COT-DCM反激PFC变换器同样高的功率因数。最后,通过仿真和实验验证了理论分析的正确性。
[Abstract]:With the wide application of power electronic equipment, AC-DC switching converter has brought serious harmonic pollution to public power grid. Power factor correction (PFC) technology can effectively eliminate harmonic pollution in power system. Therefore, PFC technology has been widely used in AD-DC switching converters. Single switch isolated PFC converters are widely used in the field of PFC technology because of their advantages of input and output isolation, low cost, simple structure and so on. The flyback PFC converter is the most popular. Generally speaking, because the leakage inductance of transformer needs to be consumed by the RCD snubber circuit, it can avoid the large voltage and current spike in the circuit. The efficiency of flyback PFC converter will be limited by its snubber circuit. High efficiency isolated PFC converter. The switching current peak envelope of the traditional Peak Current controlled PFC (PFC) flyback PFC converter follows the input sinusoidal half-wave voltage. The input current is not a standard sinusoidal wave. In this paper, a sine squared compensated peak current control Square Compensated Peak Current controlled S2C-PCCCmethod is proposed to compensate a sinusoidal squared term in the switching tube peak current envelope of the PCC-CRM flyback PFC converter. The coefficient is determined by the amplitude of the input voltage, the output voltage and the turn ratio of the primary secondary coil of the transformer. The peak value of the switching current is controlled by the compensated peak current envelope. In order to reduce the energy loss of transformer leakage inductance in CRM flyback PFC converter, the unit power factor is realized in the full input voltage range. Finally, the correctness of theoretical analysis is verified by simulation and experiment. In order to reduce the energy loss of transformer leakage inductance in CRM flyback PFC converter, the efficiency of converter is improved. In this paper, a resonant network composed of resonant capacitor, transformer leakage inductance and diode is introduced into the transformer side of CRM flyback PFC converter for the first time. The leakage inductance energy of the converter is transferred to the load and the efficiency of the converter is improved. The voltage stress of the switch and diode is reduced. At the same time, the constant on time control method is used to make the input current of the converter more sinusoidal. The correctness of the theoretical analysis is verified by simulation and experiment. Similarly, the resonant network is introduced into discontinuous Conduction mode flyback PFC converter, which solves the problem of low efficiency of DCM flyback PFC converter. However, the original standard sinusoidal input current is seriously distorted. Therefore, in order to eliminate the adverse effects of the resonant network on the DCM flyback PFC converter, In this paper, the VOT control method is applied to the DCM single-switch resonant isolation PFC converter. By introducing input voltage and output voltage to adjust the switching on time together, the VOT-DCM single-switch resonant isolation PFC converter has a high working efficiency. At the same time, it can maintain the same high power factor as the COT-DCM flyback PFC converter. Finally, the correctness of the theoretical analysis is verified by simulation and experiment.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46

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