随着社会的发展，整个社会对供电的要求越来越高，依赖也越来越大，然而电力故障的突发性强，往往不以人的意志为转移，无论供电部门管理得多严格，电网设施多先进，断电也在所难免。因此EPS作为一种应急供电设备得到越来越广泛的应用。 本文首先介绍了三相应急电源的背景和发展趋势，在分析了传统应急电源的特点和局限性的基础上，从简化电路结构、降低产品成本的角度出发提出了一种新型三相应急电源系统，系统主要有两个重要组成部分：双向DC/DC电路和双向PWM变流器。 其次，分别对双向DC/DC电路和双向PWM变流器进行了详细的分析。对于双向DC/DC电路，通过对四种典型的非隔离双向DC/DC变换器的比较分析，提出了适用于蓄电池储能系统的双向半桥DC/DC 变换器。分别对变换器降压模式和升压模式下的工作过程进行了细致的分析，使用平均值等效电路法建立了变换器两种工作模式下的小信号模型，在此基础上对蓄电池充放电的闭环控制策略进行了研究，并给出了电路相关参数的设计方法。 对于双向PWM变流器，电网正常时，电网通过静态转换开关直接向负载供电，同时将网侧有功能量经双向PWM变换器整流再由DC/DC电路降压后提供给蓄电池充电电路。电网故障时，双向PWM变换器工作在逆变器状态，将直流电压变换成交流电压再经过低通滤波器向负载提供稳定的三相正弦电压。重点分析了逆变主电路的拓扑结构并建立了数学模型，设计了逆变系统的双闭环控制，给出了数字化的实现方法。对逆变电路中应用最多的正弦波脉宽调制技术的调制方式与采样方法进行了介绍。 最后，根据控制系统的整体方案，采用DSP作为控制系统的主控核心芯片，设计了基于TMS320F2812的新型三相应急电源控制系统的硬件电路和软件系统。硬件部分主要包括信号采样调理电路、缓冲电路、功率驱动电路及保护电路。软件部分采用模块化的程序设计方法，给出了主程序和子程序流程图。在理论分析和系统设计的基础上，运用计算机仿真软件Matlab对系统进行仿真，并搭建样机进行实验，通过对仿真结果和实验结果的分析，验证了所建立系统模型的正确性。 综上所述，本文提出的新型应急电源系统利用双向拓扑结构实现了通常由单向电路所实现的EPS的各种功能，实现了EPS产品绿色化、智能化和低成本的要求。

As society advanced，high requirements of power supplies are needed. Society have become increasingly dependent on power supply. However, sudden accidents occurring in power supply still cannot be avoided. In spite of strict electric administration and advanced electric equipments, power cuts still happen occasionally. Therefore，EPS as one kind of emergency power supply equipments is widely used in such cases. First of all, this paper introduces the background and development trend of three-phase emergency power supply. On the basis of analysis of the characteristics and limitations of the traditional emergency power supply systems, from the view of simplifying the circuit structure and reducing product cost , we proposed a new three-phase emergency power system with two basic components of EPS circuit：Bi-directional DC/DC circuit and bi-directional PWM converter. Secondly, a detailed analysis of bi-directional DC/DC circuit and bi-directional PWM converter are carried out. For bi-directional DC/DC circuit, based on the comparative analysis of four typical non-isolated bi-directional DC/DC converter, a bi-directional half-bridge DC/ DC converter which is suitable for battery application is introduced. The BUCK and BOOST mode operation procedure of the converter are discussed separately in detail. In order to lay a solid foundation in closed-loop design, small signal models of BUCK and BOOST mode of the converter are established. The closed-loop stability is discussed and has given the electric circuit related parameter design method. Regarding the bi-directional PWM converter, when the electrical network is normal, grid through the static transfer switch directly supply power to load, at the same time, active energy of the net side will be send for battery through bi-directional PWM converter and DC/DC circuit .When electrical network break down, the bi-directional PWM converter work in the invertor condition, will transform the DC voltage into AC voltage to provide a stable three - phase sinusoidal voltage to the load after the low-pass filter. Analyzes the main circuit topology and mathematical model of the inverter,design double closed-loop control system of inverter and gives the method to realize the digitization. Introduces the basic principle of inverter sine pulse width modulation technology, which is used widely, and it’s controlling and sampling methods. Finally, according to the entire project of the control system, adopting DSP major core chip as the control system to design new three-phase emergency power control system hardware circuit and software system which bases on TMS320F2812. Hardware mainly includes signal sampling regulate circuit, buffer circuit, power drive circuit and protection circuit. The software of adopting the modular programming methods gives flow chart of the main program and sub program. In the base of the theoretical analysis and system design, using computer simulation software Matlab, and building prototype to conduct the experiment in order to examine the correctness of the model system which is established through the simulation results and the analysis of experimental. To sum up, this paper comes up with the new emergency power system, by using two-way topological structure to realize all functions that usually by using the unidirectional circuit, in the meanwhile, to reach the greenization, intelligent and low-cost requirements of EPS products.