Problem10-6 A forward converter with demagnetizing winding isdesired to operate wit a maximum duty ratio Dmax of 0.7.calculate the voltage rating of the switching in terms of theinput voltage Vd
7 10-6 A forward converter with demagnetizing winding is desired to operate wit a maximum duty ratio Dmax of 0.7. calculate the voltage rating of the switching in terms of the input voltage Vd . Problem
Problem10-7 In the circuit of Fig. 10-12b with two parallel forwardconverter, draw the input current ia and i, waveforms if eachconverter is operating at a duty ratio of o.3 in a continuous-conduction mode.Comparethesetwo waveformswiththose ifa singleforwardconverter (withtwicethe powerrating but with the same valueoftheoutputfilterinductance asinFig.10-12b)is used.Assuming V。(t)=V。V1(b)Figure 10-12 Other topologies of forward converter: (a) two-switchforward converter; (b) parallelled forward converters
8 10-7 In the circuit of Fig. 10-12b with two parallel forward converter, draw the input current id and iL waveforms if each converter is operating at a duty ratio of 0.3 in a continuousconduction mode. Compare these two waveforms with those if a single forward converter (with twice the power rating but with the same value of the output filter inductance as in Fig. 10-12b) is used. Assuming vo (t)≈Vo . Problem
Problem10-8 In the push-pull converter of Fig.10-13a,assume thelosses to be zero and each switch duty ratio to be 0.25. Thetransformer has a finite magnetizing inductance and im isthe magnetizing currentiDi(a) At a large load whereiL(N2/N,)>>im, draw the im, ip1,and ip2 waveform.Figure10-13Push-Fullconverter
9 10-8 In the push-pull converter of Fig. 10-13a, assume the losses to be zero and each switch duty ratio to be 0.25. The transformer has a finite magnetizing inductance and im is the magnetizing current. (a) At a large load where iL (N2 /N1 )>>im, draw the im, iD1, and iD2 waveform. Problem
ProblemStep-downconverters7-1 In a step-down converter, consider all components to beideal. Let v=V.be held constant at 5V by controlling theswitch duty ratio D. calculate the minimum inductance Lrequired to keep the converter operation in a continuous-conduction mode under all conditions if V.is 10~40V,P。>=5W,and f,=50kHz.idioYYL+1oVL大VdC.1.(a)O
Problem Step-down converters 7-1 In a step-down converter, consider all components to be ideal. Let vo=Vo be held constant at 5V by controlling the switch duty ratio D. calculate the minimum inductance L required to keep the converter operation in a continuousconduction mode under all conditions if Vd is 10~40V, Po>=5W, and fs=50kHz. + Vd - + vL - R + C vo=Vo - + voi - (a) L i i L d io 9
Problem7-2 Consider all components to be ideal. Assume V。=5V,f.=20kHz, L=1mH,and C=470μF.Calculate △V。(peak-peak)if Va=12.5V,and l.=200mA.7-3 In Problem 7-2, calculate the rms value of the ripplecurrent through L and, hence, through C.10
Problem 10 7-2 Consider all components to be ideal. Assume Vo=5V, fs=20kHz, L=1mH, and C=470µF. Calculate ΔVo (peak-peak) if Vd=12.5V, and Io=200mA. 7-3 In Problem 7-2, calculate the rms value of the ripple current through L and, hence, through C