摘要
摘要
同步整流技术多应用于低压输出的开关电源之中，其基本原理是利用MOSFET的通态电阻极低这一特性来降低电路损耗。随着新型电子产品对供电要求的不断提高，同步整流电路越来越广泛地应用于低压大电流输出环境中。但是单相的同步整流电路输出能力有限且随着输出电流增大，转换效率会降低。本课题即针对以上问题研究了多相同步整流电路并联运行的解决方案。在该方案中，其关键技术是实现多相并联同步整流电路的均流输出。
本文在分析同步整流电路拓扑结构和现有均流技术的前提下，选取双管正激为基本拓扑结构，并对原有结构做了改进；在控制方法方面，采用最大电流自动均流法作为均流控制的主要控制策略；本文介绍了并联模块电路的主要参数的设计方法，包括输入、输出滤波电容的计算与选择，变压器的参数设计，驱动电路的设计等；利用DSP实现系统的数字PID控制。本文设计了一种全新的控制方式，使得电路可以根据负载变化自动切换工作模式，保证电路在不同负载条件下都能达到最优的转换效率，从而提高了多相并联电源的功率密度以及可靠性。
利用Matlab自带的Simulink平台搭建了三相并联同步整流电路仿真模型，分别对单相的同步整流电路和三相并联电路进行了仿真，通过改变电路的负载测得电路在不同负载条件下的转换效率。仿真结果证明，多相并联同步整流电路可以解决单相电路负载能力有限的问题，仿真结果同时说明，利用多相并联技术，电路的等效工作频率得到了提高，输出电压的纹波值得到了降低。
图[60] 参[57]
关键字：同步整流，多相并联，均流控制，DSP 分类号：TN86
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安徽理工大学硕士学位论文
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Abstract
Abstract
Synchronous rectification technology is used in the rectifier circuit,using low on-state resistance MOSFET rectifier diodes instead of conventional to reduce the circuit losses, along with the continuous improvement of supply requirements of the new electronic product,synchronous rectifier circuit is widely used in low voltage and high current output environment.However, the conversion and efficiency of a single phase synchronous rectifier circuit efficiency will be reduced along with the increases of output current.In this paper,parallel operation solutions is sdudied of the multiphase synchronous rectifier circuit. In this scenario, the core technology is to achieve the average output current between modules.
Based on the premise of analyzing synchronous rectifier circuit topology and existing current sharing technology, the double forward circuit isselected as the basic structure and the original structure has been improved. Maximum current automatic current law is the main method of control strategy. The main parameters of the parallel module circuit was designed,including calculation and selection of the input and output filter capacitor,parameter design of the transformer and design of drive circuit. The DSP is used as a PID controller to control of the entire system. A new control method is designed to ensure the circuit automatically switch woke-mode according to the changed load.The circuit is set to achieve maximum conversion efficiency under different load conditions.The reliability and power density of the circuit is improved.
Using Matlab / Simulink to build a three-phase parallel synchronous rectifier circuit simulation platform. Single-phase and three-phase synchronous rectifier circuit parallel circuit was simulated respectively,and the circuit conversion efficiency was measured under different load conditions by changing the circuit load. The simulation results show that the multi-phase synchronous rectifier circuit could save the problem of the limited load capacity of a single-phase circuit, the simulation results also shows that useing multiphase technology can improve the equivalent frequency and reduce the value of the output voltage ripple .
Figure[60] Reference[57]
Keywords: Synchronous rectification，Multiphase Parallel，Current Sharing，DSP
Chinese books catalog：TN86
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安徽理工大学硕士学位论文
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