基于串并联谐振变换器的高压电容器充电电源研究

发布时间：2018-10-10 07:01

【摘要】：脉冲功率技术在高新技术产业及新型武器如辐射消毒、烟气净化、生物工程、电磁脉冲武器等方面得到了十分广泛的应用。而电容器储能因为简单可靠、技术成熟,成为脉冲功率技术最常用的储能方式。作为电容器储能的前级,电容器充电电源有着不可或缺的作用。因此,对电容器充电电源拓扑及控制方法的研究显得十分重要。在用于电容器充电电源的电路拓扑中,串联谐振变换器(Series Resonant Converter,SRC)是最常用、最成熟的一种拓扑。它具有控制简单、能够实现软开关、工作在电流断续模式下具有恒流源特性、抗负载短路能力强等优点。但是,SRC的电压增益小于1,且高压变压器分布参数的存在使得SRC的工作特性发生变化。为此,本文选择了串并联谐振变换器(Series-Parallel Resonant Converter,SPRC)作为充电电源的拓扑结构。SPRC不仅具有一定的抗短路能力、能够实现软开关的优点,还可以利用高压变压器的分布参数作为谐振元件,同时其电压增益高于1。本文首先分析了工作在电流连续模式下SPRC的工作原理,说明了SPRC存在三种工作模式及各种模式的优劣,并选定强迫换流模式为最优的工作模式。其次,运用扩展描述函数法建立了SPRC的大信号模型,再由大信号模型得到稳态模型与稳态等效电路。从所得的模型出发,推导了强迫换流模式的边界,通过图解的方法研究了负载品质因数、开关频率、并联谐振电容等相关参数对SPRC特性的影响,为电容器充电电源的设计提供了理论指导。根据SPRC的特性,在兼顾谐振槽电压电流峰值、电压增益、充电电流等指标的基础上,给出了电容器充电电源参数的设计方法,设计了一种基于变频控制的恒流充电方案。该控制方案不仅实现了恒流充电,同时也实现了开关管的零电压开通。通过仿真验证了模型的准确性及控制方案的可行性。最后,设计了一台额定输出电压为3kV、充电功率为825J/s的电源样机,并进行有关的实验,实验结果证明了理论分析的合理性和控制方案的有效性。
[Abstract]:Pulse power technology has been widely used in high-tech industries and new weapons such as radiation disinfection, flue gas purification, biological engineering, electromagnetic pulse weapons and so on. Because of its simplicity and reliability, capacitor energy storage has become the most commonly used energy storage method in pulse power technology. As the front stage of capacitor energy storage, capacitor charging power supply plays an indispensable role. Therefore, it is very important to study the topology and control methods of capacitor charging power supply. The series resonant converter (Series Resonant Converter,SRC) is the most common and mature topology in the circuit topology of capacitor charging power supply. It has the advantages of simple control, soft switching, constant current source characteristics in current intermittent mode and strong resistance to load short circuit. However, the voltage gain of SRC is less than 1, and the distribution parameters of high voltage transformer make the operating characteristics of SRC change. In this paper, series and parallel resonant converter (Series-Parallel Resonant Converter,SPRC) is chosen as the topology of charging power supply. SPRC not only has the capability of resisting short circuit, but also can use the distributed parameters of high voltage transformer as resonant element. At the same time, the voltage gain is higher than 1. In this paper, the principle of SPRC working in current continuous mode is analyzed, and the advantages and disadvantages of three modes of SPRC are explained, and the forced commutation mode is chosen as the optimal mode of operation. Secondly, the large signal model of SPRC is established by using the extended description function method, and the steady state model and steady state equivalent circuit are obtained from the large signal model. Based on the obtained model, the boundary of forced commutation mode is derived, and the effects of load quality factor, switching frequency, parallel resonant capacitance and other related parameters on the characteristics of SPRC are studied by graphic method. It provides theoretical guidance for the design of capacitor charging power supply. According to the characteristics of SPRC and taking into account the peak voltage and current, voltage gain and charging current, the design method of capacitor charging power supply parameters is given, and a constant current charging scheme based on frequency conversion control is designed. This control scheme not only realizes constant current charging, but also realizes zero-voltage switch-on. The accuracy of the model and the feasibility of the control scheme are verified by simulation. Finally, a prototype of a power supply with rated output voltage of 3 kV and charging power of 825J/s is designed. The experimental results show that the theoretical analysis is reasonable and the control scheme is effective.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM46;TM53

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