基于极谐振软开关的PWM功率放大器研究与设计

发布时间：2018-03-12 13:38

本文选题：PWM功率放大器　切入点：极谐振软开关　出处：《电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：光刻机系统是电子元器件的制造装备,超精密平面电机及其伺服驱动是其中极其关键的部件,是决定光刻机系统精度的动力来源。用于驱动超精密平面电机的PWM功率放大器的在国内研究空白,且国外对中国的技术封锁,开展应用于该领域的PWM功率放大器的研究具有重要的意义。本文首先对PWM功率放大器中的两个关键模块进行了理论研究,包括功率拓扑和电流控制器。开关频率越高,输出电流纹波峰峰值越小,且系统可获得更好的动态响应。但随着开关频率的增大,传统硬开关电路的开关损耗和电磁干扰(EMI)都随之增大,软开关技术能有效解决这些问题。在诸多软开关电路中,极谐振软开关由于结构简单,应用广泛。本文对基本的极谐振拓扑进行了详细的理论推导,进而研究了改进的极谐振拓扑。PWM变换器的电流控制方法有很多种,由于滞环法的反馈电路结构简单,易实现,且属于闭环控制,动态响应好,应用也最为广泛。本文对滞环电流控制方法进行了理论分析,讨论了应用于极谐振软开关功率拓扑的变环宽滞环电流控制方法的理论。当功率拓扑中使用了自举电路来驱动桥臂高侧的开关器件时,滞环电流控制的变换器的低侧开关的最小导通时间和最大占空比便得不到保证,本文采用了电感电流变化率反馈来解决该问题的方法。在以上理论基础上,本文对样机的电路原理图进行了详细的设计。在基本的极谐振软开关拓扑基础上,设计了改进后的极谐振拓扑电路。提出了以开关频率、滤波器谐振频率以及最大占空比为依据的方法,来设计极谐振软开关和滤波器的元器件参数。由于MOSFET的栅极驱动能力决定了整个环路的开关频率,故主要依据开关速度参数对该电路进行了详细的参数设计。反馈电路是变环宽滞环电流控制实现的硬件基础,对整个系统的性能也有着重要的影响,本文提出了反馈电流的采样方案,设计出滞环电流控制实现的霍尔传感器采样电路以及电流互感器采样电路。最后设计了其他功能模块,如主控模块电路、上位机接口、过流保护电路和电源模块等。基于PWM功率放大器的原理图以及变环宽滞环电流控制的原理,加工出样机,设计了基于FPGA的主控程序,并在此基础上进行了原理验证实验。实验结果证明了理论分析和原理设计的正确性与可行性。
[Abstract]:The lithography system is the manufacturing equipment of electronic components. The ultra-precision planar motor and its servo drive are the most important parts. The PWM power amplifier used to drive the ultra-precision planar motor is a blank in domestic research, and the technology of foreign countries is blocked against China. It is of great significance to study the PWM power amplifier applied in this field. Firstly, two key modules of PWM power amplifier are studied theoretically, including power topology and current controller. The higher the switching frequency, the higher the switching frequency. The smaller the peak value of output current ripple, and the better the dynamic response of the system, but with the increase of switching frequency, the switching loss and electromagnetic interference (EMI) of traditional hard-switching circuits increase. The soft switching technology can effectively solve these problems. In many soft switching circuits, the pole resonant soft switch is widely used because of its simple structure. In this paper, the basic pole resonant topology is derived in detail. The current control methods of the improved pole resonant topology. PWM converter are studied. Because the feedback circuit of hysteretic method is simple, easy to realize, and belongs to closed loop control, the dynamic response is good. The hysteresis current control method is theoretically analyzed in this paper. This paper discusses the theory of variable loop wide hysteresis current control method applied to the polarity soft switching power topology. When the bootstrap circuit is used to drive the high side switch devices of the bridge arm in the power topology, The minimum on time and maximum duty cycle of the low side switch of hysteresis current controlled converter can not be guaranteed. In this paper, the method of feedback of inductance current change rate is adopted to solve this problem. In this paper, the circuit schematic diagram of the prototype is designed in detail. On the basis of the basic pole resonant soft switch topology, the improved pole resonant topology circuit is designed. The resonant frequency and the maximum duty cycle of the filter are used to design the resonant soft switch and the component parameters of the filter. The switching frequency of the whole loop is determined by the gate drive ability of the MOSFET. The feedback circuit is the hardware foundation for the realization of hysteresis current control with variable loop width, and it also has an important influence on the performance of the whole system. In this paper, the sampling scheme of feedback current is proposed, the Hall sensor sampling circuit and current transformer sampling circuit are designed for hysteresis current control, and other functional modules, such as main control module circuit, upper computer interface, are designed. Based on the schematic diagram of PWM power amplifier and the principle of hysteresis current control with variable loop width, the prototype is machined and the main control program based on FPGA is designed. The experimental results show that the theoretical analysis and principle design are correct and feasible.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN722.75

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