实验一DC-DC变换电路的性能研究一、实验目的熟悉Matlab的仿真实验环境,熟悉Buck电路、Boost电路、Cuk电路及单端反激变换(Flyback)电路的工作原理,掌握这几种种基本DC-DC变换电路的工作状态及波形情况,初步了解闭环控制技术在电力电子变换电路中的应用。二、实验内容1.Buck变换电路的建模,波形观察及相关电压测试2.Boost变换电路的建模,波形观察及相关电压测试;3.Cuk电路的建模,波形观察及电压测试;4.单端反激变换(Flyback)电路的建模,波形观察及电压测试,简单闭环控制原理研究。(一)Buck变换电路实验(1)电感电容的计算过程:VV500,电流连续时,D=0.4;临界负载电流为I=2050=2.5A;保证电感电流连续:)1(20DIfVLs=5.210002024.0-150)(=0.375mH纹波电压0.2%=ssfLCfDV8-10)(,在由电感值0.375mH,算出C=31.25uF。(2)仿真模型如下:在20KHz工作频率下的波形如下:示波器显示的六个波形依次为:MOSFET的门极电压、流过电阻两端的电流、电感电流、输出电压、MOSFET电流及续流二极管电流的波形。在50KHz工作频率下的波形如下:示波器显示的六个波形一次为:MOSFET的门极电压、流过电阻两端的电流、电感电流、输出电压、MOSFET电流及续流二极管电流的波形;建立仿真模型如下:(3)输出电压的平均值显示在仿真图上,分别为49.85,49.33;(4)提高开关频率,临界负载电流变小,电感电流更容易连续,输出电压的脉动减小,使得输出波形应更稳定。(二)Boost变换电路实验(1)电感电容的计算过程:升压比M=SVV0=D11,0V=15V,SV=6V,解得D=60%;纹波电压0.2%=scffD,cfRC1,sf=40KHz,求得L=12uH,C=750uf。建立仿真模型如下:(2)输入电压6V时,MOSFET的门极电压、电感电压、电感电流、输出电压、续流二极管电流、MOSFET的电流波形如下:(3)测量输出电压的平均值并显示,示值为14.71;(4)减小电感值到4uH,使电感电流不连续,其余条件不变,建立仿真模型如下:输入电压6V时,MOSFET的门极电压、电感电压、电感电流、输出电压、续流二极管电流、MOSFET的电流波形如下:(4)电感小于临界值时,电感电流断流,输出电压波形的幅度变大,但是输出电压的纹波大小不变,波形的变化趋势不变。(三)Cuk变换电路(1)建立仿真模型如下:(2)记录的MOSFET的门极电压、电源电流、电感电流波形如下:续流二极管电流、MOSFET的电流波形如下:电容电压UC1的输出电压波形如下:输出电压波形如下:(3)在5~30V输出电压的平均值,改变占空比D的值,测量对应输出电压的平均值如下:D=20%,V0=4.185V;D=25%,V0=5.838V;D=30%,V0=7.721V;D=35%,V0=9.883V;D=40%,V0=12.39V;D=45%,V0=15.33V;D=50%,V0=18.81V;D=55%,V0=23V;D=60%,V0=28.12V。占空比D与输出电压平均值的关系曲线如下:(四)flyback变换电路实验(1)建立仿真模型如下:(2)记录输出的电压波形如下:变压器原边绕组电流、变压器副边绕组电流波形:(3)输出电压的平均值依次为:4.672,15.59,-15.59。(4)分析PID控制的作用:提高系统的快速性,消除系统的静态误差,但使系统的动态性能变差。实验二DC-AC的变换性能研究(一)单相逆变电路实验(a)方波逆变方式(1)建立仿真模型由于要求输出电压频率为50Hz,所以周期为0.02s,方波脉冲设置参数为:(2)电阻负载R=30Ω时①负载电压,负载电流波形(万用表显示):00.010.020.030.040.050.060.070.080.090.1-300-200-1000100200300时间电压负载电压Ub:SeriesRLCBranch00.010.020.030.040.050.060.070.080.090.1-10-50510时间电流负载电流Ib:SeriesRLCBranch②电源电流,负载电压,负载电流,门极T1,T4电压,门极T2,T3电压波形(示波器显示):(3)RL负载R=20Ω,L=60mH时基波电流ia=4VD/π*错误!未找到引用源。sin(wt-φ1)计算得电流初始值为-9.5A①负载电压,负载电流波形(万用表显示):00.010.020.030.040.050.060.070.080.090.1-300-200-1000100200300Ub:SeriesRLCBranch00.010.020.030.040.050.060.070.080.090.1-15-10-5051015Ib:SeriesRLCBranch②电源电流,负载电压,负载电流,门极T1,T4电压,门极T2,T3电压波形(示波器显示):(4)电感负载L=100mH时由于电感电流滞后电压90°,根据课本94页计算公式Iam=VD/4fL,可计算得电感电流初始电流为-15A,故设置如下:①负载电压,负载电流波形(万用表显示):00.010.020.030.040.050.060.070.080.090.1-300-200-1000100200300负载电压Ub:SeriesRLCBranch00.010.020.030.040.050.060.070.080.090.1-15-10-5051015负载电流Ib:SeriesRLCBranch②电源电流,负载电压,负载电流,门极T1,T4电压,门极T2,T3电压波形(示波器显示):(5)R=30Ω时输出电流的FFT分析(b)SPWM方式(1)建立仿真模型(2)电阻负载R=30Ω时①负载电压,负载电流波形(万用表显示):00.0020.0040.0060.0080.010.0120.0140.0160.0180.02-300-200-1000100200300Ub:SeriesRLCBranch00.0020.0040.0060.0080.010.0120.0140.0160.0180.02-10-50510Ib:SeriesRLCBranch②电源电流,负载电压,负载电流,门极T1,T4电压,门极T2,T3电压波形(示波器显示):(3)RL负载R=20Ω,L=60mH时①负载电压,负载电流波形(万用表显示):00.0050.010.0150.020.0250.030.0350.040.0450.05-300-200-1000100200300Ub:SeriesRLCBranch00.0050.010.0150.020.0250.030.0350.040.0450.05-1.5-1-0.500.511.5Ib:SeriesRLCBranch②电源电流,负载电压,负载电流,门极T1,T4电压,门极T2,T3电压波形(示波器显示):(4)电感负载L=100mH时①负载电压,负载电流波形(万用表显示):00.0050.010.0150.020.0250.030.0350.040.0450.05-300-200-1000100200300Ub:SeriesRLCBranch00.0050.010.0150.020.0250.030.0350.040.0450.05-1-0.500.51Ib:SeriesRLCBranch②电源电流,负载电压,负载电流,门极T1,T4电压,门极T2,T3电压波形(示波器显示):(二)三相逆变电路实验(a)方波逆变方式(1)建立仿真模型由于要求输出电压频率为50Hz,所以周期为0.02s,方波脉冲设置参数为(2)电阻负载R=30Ω时①负载电压,负载电流波形(万用表显示):00.020.040.060.080.1-2000200Ub:Loada00.020.040.060.080.1-2000200Ub:Loadb00.020.040.060.080.1-2000200Ub:Loadc00.020.040.060.080.1-505Ib:Loada00.020.040.060.080.1-505Ib:Loadb00.020.040.060.080.1-505Ib:Loadc②电源电流,负载电压,负载电流波形(示波器显示):(3)RL负载R=20Ω,L=60mH时①负载电压,负载电流波形(万用表显示):00.020.040.060.080.1-2000200Ub:Loada00.020.040.060.080.1-2000200Ub:Loadb00.020.040.060.080.1-2000200Ub:Loadc00.020.040.060.080.1-505Ib:Loada00.020.040.060.080.1-505Ib:Loadb00.020.040.060.080.1-505Ib:Loadc②电源电流,负载电压,负载电流波形(示波器显示):(4)电感负载L=100mH时①负载电压,负载电流波形(万用表显示):00.020.040.060.080.1-2000200Ub:Loada00.020.040.060.080.1-2000200Ub:Loadb00.020.040.060.080.1-2000200Ub:Loadc00.020.040.060.080.1-505Ib:Loada00.020.040.060.080.1-10010Ib:Loadb00.020.040.060.080.1-10010Ib:Loadc②电源电流,负载电压,负载电流波形(示波器显示):(5)R=30Ω时a相输出电流的FFT分析(b)SPWM方式(1)建立仿真模型(2)电阻负载R=30Ω时①负载电压,负载电流波形(万用表显示):00.010.020.030.040.050.060.070.080.090.1-200-1000100200Ub:Loada00.010.020.030.040.050.060.070.080.090.1-200-1000100200Ub:Loadb00.010.020.030.040.050.060.070.080.090.1-200-1000100200Ub:Loadc00.010.020.030.040.050.060.070.080.090.1-505Ib:Loada00.010.020.030.040.050.060.070.080.090.1-505Ib:Loadb00.010.020.030.040.050.060.070.080.090.1-505Ib:Loadc②电源电流,负载电压,负载电流波形(示波器显示):(3)RL负载R=20Ω,L=60mH时①负载电压,负载电流波形(万用表显示):00.020.040.060.080.1-2000200Ub:Loada00.020.040.060.080.1-2000200Ub:Loadb00.020.040.060.080.1-2000200Ub:Loadc00.020.040.060.080.1-505Ib:Loada00.020.040.060.080.1-4-2024Ib:Loadb00.020.040.060.080.1-505Ib:Loadc②电源电流,负载电压,负载电流波形(示波器显示):(4)电感负载L=100mH时①负载电压,负载电流波形(万用表显示):00.010.020.030.040.050.060.070.080.090.1-200-1000100200Ub:Loada00.010.020.030.040.050.060.070.080.090.1-200-1000100200Ub:Loadb00.010.020.030.040.050.060.070.080.090.1-200-1000100200Ub:Loadc00.010.020.030