90w反激型开关电源的仿真设计.doc

摘 要 开关电源不但能够节省资源保护环境，还为人们带来巨大的经济效益，这使得开关电源的发展成为一种必然趋势。而反激型开关电源使用到的元器件的个数少、电路简单、成本低、可靠性高，伴随着人们对小型化消费类电子产品的需求日益增高，小功率开关电源的需求也随之增高，所以反激型开关电源得到了广泛的应用。 反激型开关电源主要由4个部分组成，即主电路、控制电路、检测及保护电路和其他电路。主电路也就是反激型电路，控制电路采用UC3842这种PWM集成控制芯片组成。在确定了反激型开关电源的整体拓扑后，联系需要达到的技术指标，通过计算可以得到主要元器件母线电容、变压器、MOSFET的相关参数。对于一些辅助型器件的参数可以在仿真软件中进行调试得到。功率因数的校正使用有源功率因数校正，可以达到0.99以上。 在Multisim仿真软件中对设计出的电路拓扑进行调试和仿真验证，在整体仿真图中可以看到输出电压为20V左右，等待输出电压稳定之后电压波形为一条直线，其输出负载的电流为4.2A左右，在需要达到的技术指标中输出电压为20V，输出电流为4.5A，结果与实际需要达到的指标有一定的误差，误差在允许的范围之内，所以90W反激型开关电源的仿真设计完成。 关键词：开关电源；反激；仿真；调试 Abstract Switching power supply will not only be able to save resources to protect the environment, but also bring huge economic benefits for people, which makes the development of the switching power supply has become an inevitable trend. The number of flyback switching power supply using fewer components to the circuit is simple, low cost, high reliability, along with the demand for miniaturization of consumer electronics products of the increasing demand for small switching power supply also will increased, so the flyback type switching power supply has been widely used. Flyback switching power supply is mainly composed of four parts, namely the main circuit, control circuit, detection and protection circuits and other circuits. The main circuit is a flyback circuit, PWM control circuit using UC3842 this integrated control chips. In determining the overall topology flyback switching power supply after contact technical indicators need to reach, you can get the main components bus capacitor, transformer, MOSFET related parameters by calculation. For some parameters of the device can be assisted in the simulation software debug obtained. Power factor correction using active power factor correction, can reach more than 0.99. In Multisim software to design a circuit topology for debugging and simulation, the overall figure can be seen in the simulation output voltage of about 20V, output voltage stability after waiting voltage wavef