峰值电流开关变换器系统建模与子电路实现

发布时间：2018-06-15 02:49

本文选题：DC-DC转换器 + 开关变换器　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：电子科学技术和各类通信终端的日新月异的进展使得人类在处理各项社会活动的过程中变得越来越高效,而一个可靠性高、功耗低、性能参数优良的电源是所有通信终端与电子设备能够正常运行的首要前提。电源模块是构成一个整机系统核心部件之一,而微电子技术近些年在全球范围内的高速发展使得对各种各样模块电路的集成化成为了可能。相比于一个电子系统庞大的电源模块,集成化电源芯片的优点在于可使其功耗变低、转换效率变高、体积变小、驱动能力变强、电路可靠性变高。本文主要对峰值电流控制模式下的Buck型开关变换器进行了建模研究与子模块电路的设计实现,研究工作主要包括:分析了开关变换器的基本结构与原理。通过对开关变换器的理论研究,分析了当前开关变换器的主要类型。分析主要包括,功率级开关主回路类型,控制回路调制模式,控制采样策略,主回路导电模式。并在分析基础上得出结论:采用PWM调制,电流采样型控制,连续导电模式的转换器具有更好的输入调整率、负载调整率以及转换效率。建立了峰值电流型开关变换器的系统模型。通过理论计算,采用Simulink建立了时域模型以及采用Matlab建立了频域模型。分析了模型仿真结果并提出控制回路的控制策略。模型建立的工作依次为功率级开关回路模型,负反馈控制回路模型以及系统模型。其中开关回路建模主要包括,非理想参数的等效、大信号模型、条件假设研究、小信号模型、传递函数提取;负反馈控制回路建模主要包括,电压环路采样、电压环路误差放大器、电流环路采样、电流环路斜率补偿以及控制回路传递函数的提取;系统建模包括在控制回路闭环下对系统频域稳定性分析。验证了所建模型正确性。采用Matlab软件进行频域验证以及采用Simulink软件进行时域验证。分别分析了控制环路中电压环路与电流环路的不稳定因素,并提出了电压环路的频率补偿方法与电流环路的斜率补偿方法,稳定性仿真结果表明该补偿方法可以使电路稳定工作并具有良好的抑制输入扰动与负载扰动的能力。按照所建模型确定了开关变换器的各个模块,并确定了关键子模块的参数指标。系统仿真的结果验证了模型的正确性并实现了数学模型到系统电路模型的映射。验证了关键子模块电路的可实现性。依照所确定的子模块电路参数指标,采用IC设计软件Cadence-IC5141对子模块电路进行设计并验证其可实现性,实现了系统电路模型到子电路模型的映射。子模块电路主要包括,运算放大器,电压比较器,基准电压源,斜率补偿电路与振荡器。全文通过数学模型到系统电路模型实现第一级验证,通过系统电路模型到子模块电路模型完成第二级验证。仿真结果表明,系统模型可以完整地覆盖开关变换器的系统性能指标,系统性能指标均可由子电路模块实现,证明了所建模型具有对实际工程的指导性意义。
[Abstract]:The rapid progress of Electronic Science and technology and all kinds of communication terminals makes human beings become more and more efficient in the process of dealing with various social activities. A power supply with high reliability, low power consumption and excellent performance parameters is the primary prerequisite for the normal operation of all communication terminals and electronic devices. The power module is a whole machine. One of the core components of the system, and the rapid development of microelectronics in the world in recent years makes it possible to integrate all kinds of modular circuits. Compared to the large power modules of an electronic system, the advantages of the integrated power chip are that the power consumption can be reduced, the conversion efficiency is higher, the volume is smaller, and the driving capability is reduced. In this paper, the model of Buck type switch converter under peak current control mode is modeled and the design and Realization of sub module circuit are mainly carried out. The main research work includes the basic structure and principle of the switch converter. The current switch converter is analyzed by the theory of switch converter. Main types, including main circuit type of power level switch, modulation mode of control loop, control sampling strategy, main circuit conduction mode, and conclusion on the basis of analysis: using PWM modulation, current sampling control, continuous conduction mode converter have better input adjustment rate, load adjustment rate and conversion efficiency. The system model of the peak current switch converter is established. Through the theoretical calculation, the time domain model is established by using Simulink and the frequency domain model is set up with Matlab. The simulation results of the model are analyzed and the control strategy of the control loop is put forward. The model of the model is in turn the power level open loop model and the negative feedback control loop model in turn. The modeling of the switch loop mainly includes the equivalent of the non ideal parameters, the large signal model, the condition hypothesis research, the small signal model, the transfer function extraction; the negative feedback control loop modeling mainly includes the voltage loop sampling, the voltage loop error amplifier, the current loop sampling, the current loop slope compensation and the control loop transmission. The system modeling includes the stability analysis of the frequency domain in the closed loop control loop. The correctness of the model is verified. Matlab software is used to verify the frequency domain and the Simulink software is used to verify the time domain. The instability factors of the voltage loop and the electric current loop in the control loop are analyzed, and the voltage is proposed. The frequency compensation method of the loop and the slope compensation method of the current loop. The stability simulation results show that the compensation method can make the circuit work steadily and have a good ability to suppress the input disturbance and load disturbance. The simulation results verify the correctness of the model and realize the mapping of the mathematical model to the system circuit model. The realization of the key sub module circuit is verified. According to the parameters of the module of the sub module, the IC design software Cadence-IC5141 is used to set up the submodule circuit and verify its feasibility, and the system electricity is realized. The circuit model is mapped to the sub circuit model. The sub module circuit mainly includes the operational amplifier, the voltage comparator, the reference voltage source, the slope compensation circuit and the oscillator. The full text passes the first stage verification through the mathematical model to the system circuit model, and the second level verification is completed through the system circuit model to the submode block circuit model. The simulation results show that the simulation results show that The system model can fully cover the performance index of the switch converter, and the performance index of the system can be realized by the sub circuit module. It is proved that the model has the guiding significance for the practical engineering.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

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