采用非接触电流互感器的自激控制串串补偿非接触谐振变换器

发布时间：2019-03-19 06:59

【摘要】：非接触供电技术是近年来受到广泛专注的一项电能变换技术，其采用原副边分离的变压器，利用磁场耦合原理传输电能，其供电灵活、可靠，无火花和触电危险，因而已在人体植入设备、手机以及电动汽车充电等多种场合得到了应用。在非接触供电系统中，负载参数甚至主电路参数都要求变化。对于人体植入设备等应用场合，非接触变压器的间距及变换器负载更是实时变化，这就要求非接触供电系统具有良好的参数变化适应能力。本文以串串补偿非接触谐振变换器作为研究对象，探讨其自激控制方法的实现，以提高变换器对系统变参数的适应性并获得良好的动态性能。论文首先根据串串补偿非接触谐振变换器的互感等效模型，在考虑绕组电阻的条件下，分析并推导了变换器的输出电压增益、转移阻抗、输入阻抗以及效率传输特性，揭示了串串补偿非接触变换器的自激控制特性——通过检测变换器副边电流过零点控制逆变器开关管的通断就可以让变换器自动工作在高频增益交点、实现自激控制，并给出了相应的自激控制系统框图。论文在构建自激控制系统框图的基础上，指出变换器副边电流相位的准确检测和非接触反馈是自激控制实现的关键，并从相位检测元件、延时特性分析、延时补偿电路多方面进行了深入细致地研究，以确保自激工作点的准确性。论文提出了用于相位检测的测试绕组短路的非接触电流互感器，详细分析了其工作原理，研究了其测试误差。并从整个控制系统的角度讨论了电路各单元对电流相位信号的延时影响，指出需要加入时间延迟补偿电路进行修正。根据控制电路延时时间基本固定的特性，提出了RCR时间延迟补偿电路，保证在变换器的工作频段内实现固定时间的超前补偿。论文还结合启动阶段上管驱动电源初始建压困难的问题，，给出了解决方案，保证了启动的可靠实现。最后，论文设计并搭建了一台采用非接触电流互感器的60W自激控制串串补偿非接触谐振变换器，进行了详细的实验研究。变换器的稳态实验结果证明了所提出的非接触互感器和时间延迟补偿电路的有效性。在自激控制方法下，变换器获得了近似恒定的输出，在10mm气隙满载条件下变换器效率达89.2%，20mm气隙下效率达84%。为验证自激控制的快速响应性，论文还设计了相应的动态测试电路，相关实验证明了自激控制方法可在一个开关周期内响应变换器参数变化。论文给出的动、静态特性的实验结果充分表明所提出的自激控制串串补偿非接触谐振变换器可以自动适应变压器参数和负载参数的变化，具有良好的动态特性。
[Abstract]:Contactless power supply technology is a widely focused electric energy conversion technology in recent years. It adopts transformer which is separated from the original side and uses magnetic field coupling principle to transmit electric energy. Its power supply is flexible, reliable, non-sparking and electrocution dangerous, and its power supply is flexible, reliable and free of spark and electric shock. As a result, it has been used in many fields such as human implant device, mobile phone and electric vehicle charging and so on. In the contactless power supply system, the load parameters and even the main circuit parameters need to be changed. For applications such as human implanted equipment, the distance between non-contact transformers and the load of the converter are changed in real time, which requires the non-contact power supply system to have a good adaptability to the variation of parameters. In this paper, the serial compensation contactless resonant converter is taken as the research object, and the realization of its self-excitation control method is discussed in order to improve the adaptability of the converter to the variable parameters of the system and obtain good dynamic performance. Firstly, according to the mutual inductance equivalent model of series compensation contactless resonant converter, the output voltage gain, transfer impedance, input impedance and efficiency transmission characteristics of the converter are analyzed and deduced under the condition of considering winding resistance. The self-excited control characteristic of series compensation contactless converter is revealed. The self-excited control can be realized by detecting the switching on and off of the inverter switch controlled by the side current crossing zero, which can make the converter work at the high frequency gain intersection automatically, and realize the self-excited control by detecting the switching on and off of the inverter. The block diagram of self-excited control system is given. Based on the frame diagram of the self-excited control system, it is pointed out that the accurate detection and non-contact feedback of the secondary current phase of the converter is the key to the realization of the self-excited control, and the delay characteristics of the converter are analyzed from the phase detection elements and the delay characteristics. The delay compensation circuit is studied in many aspects in order to ensure the accuracy of the self-excited working point. In this paper, a non-contact current transformer for measuring winding short circuit for phase detection is proposed, its working principle is analyzed in detail, and its testing error is studied. From the point of view of the whole control system, the delay effect of each unit of the circuit on the current phase signal is discussed, and it is pointed out that the time delay compensation circuit should be added to modify the current phase signal. According to the characteristic that the delay time of the control circuit is fixed, the RCR time delay compensation circuit is proposed to ensure that the fixed time advance compensation can be realized in the working frequency band of the converter. Combined with the difficulty of the initial build-up of the tube driving power supply in the start-up phase, the solution is given to ensure the reliable realization of the start-up. Finally, a 60W self-excited control series compensated contactless resonant converter with contactless current transformer is designed and built, and a detailed experimental study is carried out. The steady-state experimental results of the converter demonstrate the effectiveness of the proposed contactless transformer and time delay compensation circuit. Under the self-excited control method, the output of the converter is approximately constant. The efficiency of the converter is up to 89.2% under the full load condition of 10mm air gap and 84% under 20mm air gap. In order to verify the fast response of self-excitation control, the corresponding dynamic test circuit is also designed. The experiments show that the self-excitation control method can respond to the change of converter parameters in a switching period. The experimental results of dynamic and static characteristics show that the proposed series compensation contactless resonant converter with self-excited control can automatically adapt to the change of transformer parameters and load parameters and has good dynamic characteristics.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM452;TM724

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