PEREC Basic operation principle of buck converter Buck converter with ideal switch Rsv Q Realization using +v2()- power MOSFET and diode R
Power Electron cs i 6 Basic operation principle of buck converter Basic operation principle of buck converter Buck converter with Buck converter with ideal switch ideal switch Realization using Realization using power MOSFET power MOSFET and diode and diode
Thought process in analyzing basic DC/DC converters 4 Basic operation principle( qualitative analysis How does current flows during different switching states How is energy transferred during different switching states 4 Verification of small ripple approximation 4 Derivation of inductor voltage waveform during different SWItching states 4 Quantitative analysis according to inductor volt-second balance or capacitor charge balance 7
Power Electron cs i 7 Thought process in analyzing basic Thought process in analyzing basic DC/DC converters DC/DC converters Basic operation principle (qualitative analysis) Basic operation principle (qualitative analysis) – How does current flows durin How does current flows during different switching states g different switching states – How is energy transferred duri energy transferred during different switching states ng different switching states Verification of small ripple approximation Verification of small ripple approximation Derivation of inductor voltage waveform during different Derivation of inductor voltage waveform during different switching states switching states Quantitative analysis according to inductor volt Quantitative analysis according to inductor volt -second balance or capacitor charge balance balance or capacitor charge balance
F Actual output voltage waveform of buck converter 0)L Buck converter +V21 containing practical v R low-pass filter Actual output voltage actual waveform waveform v(t)=V+ripple vt=V+ ripple(t) Dc component I
Power Electron cs i 8 Actual output voltage waveform of buck converter Buck converter Buck converter containing practical containing practical low -pass filter pass filter Actual output voltage Actual output voltage waveform waveform v ( t) = V + vripple ( t )
PEREC The small ripple approximation v(t) actual waveform v()=+v) v(t=V+ ripple(t) y Dc component j In a well-designed converter, the output voltage ripple is small. Hence, the waveforms can be easily determined by ignoring the ripple I vrpe<<v
Power Electron cs i 9 The small ripple approximation The small ripple approximation v ( t) = V + vripple ( t ) In a well In a well -designed converter, the output voltage ripple is designed converter, the output voltage ripple is small. Hence, the waveform small. Hence, the waveforms can be easily determined by s can be easily determined by ignoring the ripple: ignoring the ripple:
Buck converter analysis inductor current waveform 1)L original converter I R vt) switch in position 1 switch in position 2 rATAN +V1D)- ○ R
Power E l ect r o n cs i 10 Buck converter analysis: Buck converter analysis: inductor current waveform inductor current waveform