能馈型电子负载的研究

【作者】 于峰昌；

【导师】 黄运生； 张泰山；

【作者基本信息】 中南大学 ， 电力电子与电力传动， 2008， 硕士

【摘要】 能馈型电子负载是一种能够模拟实际电阻负载特性的新型电力电子装置,用于直流电源功率试验,并将测试的直流电能逆变为交流并入电网,实现电能的再生利用。该装置具有节能、体积小、重量轻、节省安装空间、试验性能优良等优点。本文从方案分析入手,详细讨论了整个系统的难点、重点,并给出相对较优的解决方案。系统由具有高频链的DC-DC变换器和DC-AC并网逆变器共同构成电子负载的主电路,两个部分均采用单相全桥变换电路。基于软开关的考虑,DC-DC变换选择移相全桥软开关隔离变换器,采用以UC3879为核心的移相控制策略。详细分析了DC-AC并网逆变器的控制目标和控制方式,对控制算法进行了深入的研究。整个系统中,并网电流的跟踪控制是非常关键的,DC-AC并网逆变器采用以C8051F020为核心的滞环电流控制策略,具有快速的瞬态响应和较高的稳定性,可以很好的跟踪并网电流。电子负载系统的控制部分将数字控制和模拟控制有机结合,不仅简化了控制系统的设计和调试,而且提高了系统的可靠性,为电子负载的功能进一步扩展提供了一个适应性强的软硬件平台。本文给出了主电路元器件参数的设计计算方法,主电路开关元件选择IGBT。设计了系统的驱动电路和保护电路,给出了滞环电流控制实现的程序框图。仿真结果表明,该方案较好地实现了电子负载的功能,并能实现对所模拟负载的无级调节。负载模块交流侧电流近似正弦,功率因数近似为1.0。更多还原

【Abstract】 With the development of social economy, people pay more and more attention on energy source problem. The electronic power load is a new type power electronic instrument that can run with the same function as resistors in the test of all kinds of DC power source. The electronic load transforms the DC power into AC power and sends it into the utility power system. Electronic load can save power and space because it is lighter and smaller.This paper discusses the difficulty of the power load system, and proposes a preferable design project. The system has two parts: DC-DC converter and DC-AC grid-connected inverter. They select full-bridge converter. Taking into account soft switching, The DC-DC converter select Phase-Shifted control strategy realized by UC3879.This paper detailed analysis of its control objectives and control mode, the control algorithm is in-depth study. The entire system, the tracking control of grid-connected current it is very critical. The DC-AC converter select hysteresis current control strategy realized by C8051F020. It has fast transient response and high stability. The combination of analog control and digital control can make the design and the debugging of the control system easy, and also can improve the reliability of the whole system. It is easy for this kind of structure to expand its functions in the future, which has strong adaptability.This paper presents design and calculation methods of the main components in the circuit. The main circuit switching elements is IGBT. Design of the drive and protection circuit is given. The diagram of hysteresis current control is given.The simulation results verify that the electronic load is well designed. The electronic load can be regards as a resistor whose value change smoothly. Required performance is obtained: unit power factor and the grid-connected current that is close to sinusoidal.更多还原