開(kāi)關(guān)電源基礎(chǔ)教程2.

1、開(kāi)關(guān)電源功率電路分析要點(diǎn)開(kāi)關(guān)電源功率電路分析要點(diǎn)電容的電壓不能突變, 電感的電流不能突變流經(jīng)電容的電流平均值為零, 電感兩端電壓的平均值為零理想變壓器電壓與匝數(shù)成比且同名同極性, 電流與匝數(shù)成反比且點(diǎn)進(jìn)點(diǎn)出電容恒流充電的公式為 , 電感恒壓儲(chǔ)能的公式為變壓器與電感的伏秒積必須平衡TIUC*TUIL*Buck-Boost電路工作原理：電路工作原理：VinVoDLIoS1S1S2ULILVin-VooIIoD1-DT根據(jù)L的伏秒平衡原則：Vin*DT=(Vo+2Vd)*(1-D)TVo=Vin *D/(1-D)-2VdL*Io=(Vo-2Vd)(1- D)TVds1根據(jù)L在(1-D)T時(shí)間的基本方

2、程：Io=(Vo-2Vd)(1-D)T/LDS2Vds2VinVo00.10.20.30.40.50.60.70.80.91012345678910Vo D()DVo/Vin =D/(1-D)Buck-Boost電路的輸入輸出關(guān)系：電路的輸入輸出關(guān)系：三種基本的非隔離開(kāi)關(guān)電源：三種基本的非隔離開(kāi)關(guān)電源：VinVoLIoSDVinVoDLIoS1DS2VinVoDLIoSVo=Vin *D/(1-D)Vo=Vin *DVo=Vin /(1-D)VoVin, 升壓型電路VoVin, 當(dāng)DVin 當(dāng)D0.5 升降壓型電路三種基本的隔離開(kāi)關(guān)電源：三種基本的隔離開(kāi)關(guān)電源：VinVoSLmDVinVoLS

3、D1D2VinVoLS1D1D2S2正激型變換器反激型變換器橋式變換器反激變換器（反激變換器（Flyback）工作原理工作原理 （電流連續(xù)模式）：（電流連續(xù)模式）：VgsIDVdsD1-DTIpIoVinVin+nV o根據(jù)變壓器的伏秒平衡：ImIoVinVoGDSLmDn:1TDnVoDTVin)1 (*)1 (*DnDVinVoCoVLVin-nVonVoVinVds)1 (DVinVdsID-p反激變換器（反激變換器（Flyback）工作原理工作原理 （電流斷續(xù)模式）：（電流斷續(xù)模式）：VgsIDVdsD1-DTIoVinVin+nV o根據(jù)變壓器的伏秒平衡：ImIoVinVoGDSLm

4、Dn:1)1 (*DnDVinVoCoVLVin-nVoID-p-nVoVoVo TRVoLmIp2221根據(jù)能量守恒：LmVinDTIpVinDLmRTVo2反激變換器（反激變換器（Flyback）工作原理：工作原理：VgsIDVdsD1-DTIpIoVinVin+nV oImVrVLVin-nVo221221LkIpCdsVr nIIppDID-p21DopDIDIIVr=？IoVinVoGDSLmDn:1LkCoLmTDVoID/)1 ( IpCdsLkVr*反激變換器（反激變換器（Flyback）工作原理：工作原理：IoVinVoGDSLmDn:1LkCoVcVcRPloss=(Vc-

5、Vin)2/RGDSLkVcRPloss=(Vc)2/R反激變換器（反激變換器（Flyback）工作原理：工作原理：VgsIDVdsD1-DTIpIoVinVin+nV oImVrICoID-pVo=？IoVinVoGDSLmDn:1LkCo)1/(DIIIopDCo-IoVoDTIVCOOCDTIVOO/根據(jù)Co在DT時(shí)間的基本方程：反激變換器（反激變換器（Flyback）工作原理：工作原理：VinVo1GLmNpLkVo2Ns2Ns1多路輸出的反激變換器：多路輸出的反激變換器：)1 (*11DNpDVinNsVo)1 (*22DNpDVinNsVo減小交叉調(diào)整率的措施：減小交叉調(diào)整率的措施

6、：盡量減少兩個(gè)繞組之間的漏感。在輔助輸出一路中加入尖峰抑制器（飽和電感） 主路輸出工作于電流連續(xù)模式。1.采用雙路加權(quán)反饋的控制方式反饋控制反激變換器（反激變換器（Flyback）特征總結(jié)：特征總結(jié)：VinVo1GLmNpLkVo2Ns2Ns1缺點(diǎn)：缺點(diǎn)：輸出紋波電流大。輸出控制特性非線(xiàn)性。通常需要輔助的吸收回路。1.轉(zhuǎn)換效率較低。反饋控制優(yōu)點(diǎn)：優(yōu)點(diǎn)：電路簡(jiǎn)單。輸入電壓范圍廣。 1.容易實(shí)現(xiàn)多路輸出。諧振復(fù)位正激變換器（諧振復(fù)位正激變換器（Resonant Reset Forward)：Ion:1VinVoLoGDSVgsILVdsD1-DTIpVLIoVin/n-Vo-VoImVinIL I

7、LLmLkCrt0t1 t2 t3t4Ipt0, t1t5LmVinDTIm/LoDTVonVinIL/)/(LmPInII諧振復(fù)位正激變換器（諧振復(fù)位正激變換器（Resonant Reset Forward)：Ion:1VinVoLGDSVgsILVdsD1-DTIpVLIoVin/n-Vo-VoImVinIL ILLmLkCrt0t1 t2 t3t4Ipt1, t2t5LmLkIIVVmpc211VcV諧振復(fù)位正激變換器（諧振復(fù)位正激變換器（Resonant Reset Forward)：Ion:1VinVoLGDSVgsILVdsD1-DTIpVLIoVin/n-Vo-VoImVinIL

8、 ILLmLkCrt0t1 t2 t3t4Ipt2, t3t51VcVcVrminCLDTV2諧振復(fù)位正激變換器（諧振復(fù)位正激變換器（Resonant Reset Forward)：Ion:1VinVoLGDSVgsILVdsD1-DTIpVLIoVin/n-Vo-VoImVinIL ILLmLkCrt0t1 t2 t3t4Ipt3, t4t5LmCrtt 14Lm,Cr的選取原則：22max2)1 (1*TDCrLm諧振復(fù)位正激變換器（諧振復(fù)位正激變換器（Resonant Reset Forward)：Ion:1VinVoLGDSVgsILVdsD1-DTIpVLIoVin/n-Vo-VoI

9、mVinIL ILLmLkCrt0t1 t2 t3t4Ipt4, t5t5(Vin/n-Vo)DT=Vo(1-D)T根據(jù)電感的伏秒平衡：Vo=VinD/n諧振復(fù)位正激變換器（諧振復(fù)位正激變換器（Resonant Reset Forward)特征：特征：VinVoCr缺點(diǎn)：缺點(diǎn)：原邊開(kāi)管電壓應(yīng)力較高。諧振電容的損耗大。1.寬范圍輸入效率很難兼顧。優(yōu)點(diǎn)：優(yōu)點(diǎn)：電路簡(jiǎn)單。線(xiàn)性輸出控制特性。1.不需要輔助的吸收回路。 VinVoCrVinVoCrS1, S2VpVinDVds100 50% Duty Cycle ZVS for Low side switchExcitingResetResonant

10、Reset Dual Switch ForwardVinLS2S1Sa1CrD1D2有源鉗位正激變換器（有源鉗位正激變換器（Active Clamped Forward)：Ion:1VinVoLoGDSSaILVdsDTIpVTIoVin/n-Vc/nImVinIL ILLmLkCrt0t1 t2 t3t4Ipt0, t1t5LmVinDTIm/LoDTVonVinIL/)/(LmPInIIS1S1Sa1-D+VT-有源鉗位正激變換器（有源鉗位正激變換器（Active Clamped Forward)：Ion:1VinVoLoGDSSaILVdsDIpVTIoVin/n-Vc/nImVinIL

11、 ILLmLk-Vc+t0t1 t2 t3t4Ipt1, t2t5LkIpttVcIm)() 12(S1S1Sa1-D+VT-VcLknIott/*)/() 12(1td2td* 副邊電壓的死區(qū)跟Lk和Io有關(guān)，跟原邊開(kāi)管的死區(qū)無(wú)關(guān)有源鉗位正激變換器（有源鉗位正激變換器（Active Clamped Forward)：Ion:1VinVoLoGDSSaILVdsDIpVTIoVin/n-Vc/nImVinIL ILLmLk-Vc+t0t1 t2 t3t4Ipt2, t3t5S1S1Sa1-D+VT-) 12(1tttd1td2tdSa在零電壓條件下開(kāi)通* 原邊開(kāi)管的死區(qū)時(shí)間需滿(mǎn)足：有源鉗位正激

12、變換器（有源鉗位正激變換器（Active Clamped Forward)：Ion:1VinVoLoGDSSaILVdsDIpVTIoVin/n-Vc/nImVinIL ILLmLk-Vc+t0t1 t2 t3t4Ipt3, t4t5S1S1Sa1-D+VT-1td2td激磁電流反向，變壓器被復(fù)位LmTDVcIm/)1 ( 有源鉗位正激變換器（有源鉗位正激變換器（Active Clamped Forward)：Ion:1VinVoLoGDSSaILVdsDIpVTIoVin/n-Vc/nImVinIL ILLmLk-Vc+t0t1 t2 t3t4Ipt4, t5t5S1S1Sa1-D+VT-1

13、td2td激磁電流對(duì)主開(kāi)關(guān)的輸出電容放電。t6=t0有源鉗位正激變換器（有源鉗位正激變換器（Active Clamped Forward)：Ion:1VinVoLoGDSSaILVdsDIpVTIoVin/n-Vc/nImVinIL ILLmLk-Vc+t0t1 t2 t3t4Ipt5, t6t5S1S1Sa1-D+VT-1td2tdt5時(shí)刻副邊二極管鉗位主開(kāi)關(guān)的輸出電容放電結(jié)束。t6時(shí)刻新的周期開(kāi)始t6=t0有源鉗位正激變換器（有源鉗位正激變換器（Active Clamped Forward)：Ion:1VinVoLoGDSSaILVdsDIpVTIoVin/n-Vc/nImVinIL IL

14、LmLk-Vc+t0t1 t2 t3t4Ipt5S1S1Sa1-D+VT-1td2tdt6=t0(Vin/n-Vo)DT=Vo(1-D)T根據(jù)電感的伏秒平衡：Vo=VinD/nVinDT=Vc(1-D)T根據(jù)變壓器的伏秒平衡：Vc=VinD/(1-D)Vds=Vc+VinVds=Vin/(1-D)有源鉗位正激變換器（有源鉗位正激變換器（Active Clamped Forward)：00.10.20.30.40.50.60.70.80.91012345678910Vc D()Vds D()DVc=VinD/(1-D)Vds=Vin/(1-D)Vin有源鉗位正激變換器（有源鉗位正激變換器（Act

15、ive Clamped Forward)特征：特征：VinVoVinVoVinVoSaSaSa缺點(diǎn)：缺點(diǎn)：鉗位電壓建立較慢，啟動(dòng)過(guò)程變壓器易偏磁。1.對(duì)輸入電壓的動(dòng)態(tài)響應(yīng)慢。優(yōu)點(diǎn)：優(yōu)點(diǎn)：變壓器最優(yōu)化復(fù)位（電壓應(yīng)力低）。輸入電壓范圍寬。線(xiàn)性輸出控制特性。1.不需要輔助的吸收回路。 有源鉗位正激變換器（有源鉗位正激變換器（Active Clamped Forward)： Asymmetrical Full Bridge DC/DC ConverterVinVoLS1D1D2S2半橋變換器橋式變換器（橋式變換器（Bridge Type Converter)：VinVoLS1D1D2S2全橋變換器Vi

16、nVoLS1D1D2S2推挽變換器VinVoS1D2S2半橋變換器（倍流整流）VinVoLoS1D1D2S2橋式變換器（橋式變換器（Bridge Type Converter)：n:1+1LmLkIpIoCBVTS1ILVds1DIpVTIoVin/2n-Vin/2nImVinIL t0t1t2t3 t4 t5S2Dt6=t0T/2T/2Vct0, t1變換器正半周工作，Ip, Im增加；Vc減少。LmDTVinIm/2) 12/()/(CDTnIoVcC1C1VinVoLoS1D1D2S2橋式變換器（橋式變換器（Bridge Type Converter)：n:1+1LmLkIpIoBVTS

17、1ILVds1DIpVTIoVin/2n-Vin/2nImVinIL t0t1t2t3 t4 t5S2Dt6=t0T/2T/2VcC1CC1Vin/2t1, t2S1關(guān)斷，變壓器副邊續(xù)流，原邊漏感能量被S2體二極管鉗位。VinVoLoS1D1D2S2橋式變換器（橋式變換器（Bridge Type Converter)：n:1+1LmLkIpIoBVTS1ILVds1DIpVTIoVin/2n-Vin/2nImVinIL t0t1t2t3 t4 t5S2Dt6=t0T/2T/2VcC1CC1Vin/2t2, t3S1，S2全部關(guān)斷，變壓器副邊續(xù)流，Lm保持不變，D1,D2電流之差為L(zhǎng)m。VinV

18、oLoS1D1D2S2橋式變換器（橋式變換器（Bridge Type Converter)：n:1+1LmLkIpIoABS1ILVds1DIpVTIoVin/2n-Vin/2nImVinIL t0t1t2t3 t4 t5S2Dt6=t0T/2T/2Vin/2VTVct3, t4變換器負(fù)半周工作，Ip, Im減少；Vc增加。LmDTVinIm/2) 12/()/(CDTnIoVc VinVoLoS1D1D2S2橋式變換器（橋式變換器（Bridge Type Converter)：n:1+1LmLkIpIoABS1ILVds1DIpVTIoVin/2n-Vin/2nImVinIL t0t1t2t3 t4 t5S2Dt6=t0T/2T/2Vin/2VTVct4, t5S2關(guān)斷，變壓器副邊續(xù)流，原邊漏感能量被S1體二極管鉗位。VinVoLoS1D1D2S2橋式變換器（橋式變換器（Bridge Type Converter)：n:1+1LmLkIpIoBVTS1ILVds1DIpVTIoVin/2n-Vin/2nImVinIL t0t1t2t3 t4 t5S2Dt6=t0T/2T/2VcC1CC1Vin/