chapter05 DC to DC Converters 《电力电子技术(第5版)》英文版本课件
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12
Power Electronics
Inductor voltage and current subinterval 2: switch in position 2
13
Power Electronics
Inductor voltage and current waveforms
14
Power Electronics
Determination of inductor current ripple magnitude
15
Power Electronics
Inductor current waveform during start-up transient
16
Power Electronics
The principle of inductor volt-second balance: Derivation
23
Power Electronics
Inductor voltage and capacitor current waveforms
24
Power Electronics
Inductor volt-second balance
25
Power Electronics
Conversion ratio M(D) of the boost converter
SPDT switch changes dc component
Switch output voltage waveform
Duty cycle D: 0 D 1 complement D’: D’ = 1 - D
4
Power Electronics
Dc component of switch output voltage
Verification of small ripple approximation Derivation of inductor voltage waveform during different switching states Quantitative analysis according to inductor volt-second balance or capacitor charge balance
Power Electronics
Chapter 5 DC to DC Converters
(Choppers)
Power Electronics
2
Power Electronics
3
Power Electronics
5.1 Basic DC to DC converters
Introduction—Buck converter
10
Power Electronics
Buck converter analysis: inductor current waveform
11
Power Electronics
Inductor voltage and current subinterval 1: switch in position 1
6
Power Electronics
Basic operation principle of buck converter
Buck converter with ideal switch
Realization using power MOSFET and diode
7
Power Electronics
Fourier analysis: Dc component = average value
5
Power Electronics
Insertion of low-pass filter to remove switching harmonics and pass only dc component
9
Power Electronics
The small ripple approximation
v(t) = V + vripple(t)
In a well-designed converter, the output voltage ripple is small. Hence, the waveforms can be easily determined by ignoring the ripple:
17
Power Electronics
Inductor volt-second balance: Buck converter example
18
Power Electronics
The principle of capacitor charge balance: Derivation
19
Power Electronics
26
Power Electronics
Determination of inductor current dc component
8
Power Electronics
Actual output voltage waveform of buck converter
Buck converter containing practical low-pass filter
Actual output voltage waveform
v(t) = V + vripple(t)
Boost converter example
20
Power Electronics
wk.baidu.com
Boost converter analysis
21
Power Electronics
Subinterval 1: switch in position 1
22
Power Electronics
Subinterval 2: switch in position 2
Thought process in analyzing basic DC/DC converters
Basic operation principle (qualitative analysis)
– How does current flow during different switching states – How is energy transferred during different switching states
Power Electronics
Inductor voltage and current subinterval 2: switch in position 2
13
Power Electronics
Inductor voltage and current waveforms
14
Power Electronics
Determination of inductor current ripple magnitude
15
Power Electronics
Inductor current waveform during start-up transient
16
Power Electronics
The principle of inductor volt-second balance: Derivation
23
Power Electronics
Inductor voltage and capacitor current waveforms
24
Power Electronics
Inductor volt-second balance
25
Power Electronics
Conversion ratio M(D) of the boost converter
SPDT switch changes dc component
Switch output voltage waveform
Duty cycle D: 0 D 1 complement D’: D’ = 1 - D
4
Power Electronics
Dc component of switch output voltage
Verification of small ripple approximation Derivation of inductor voltage waveform during different switching states Quantitative analysis according to inductor volt-second balance or capacitor charge balance
Power Electronics
Chapter 5 DC to DC Converters
(Choppers)
Power Electronics
2
Power Electronics
3
Power Electronics
5.1 Basic DC to DC converters
Introduction—Buck converter
10
Power Electronics
Buck converter analysis: inductor current waveform
11
Power Electronics
Inductor voltage and current subinterval 1: switch in position 1
6
Power Electronics
Basic operation principle of buck converter
Buck converter with ideal switch
Realization using power MOSFET and diode
7
Power Electronics
Fourier analysis: Dc component = average value
5
Power Electronics
Insertion of low-pass filter to remove switching harmonics and pass only dc component
9
Power Electronics
The small ripple approximation
v(t) = V + vripple(t)
In a well-designed converter, the output voltage ripple is small. Hence, the waveforms can be easily determined by ignoring the ripple:
17
Power Electronics
Inductor volt-second balance: Buck converter example
18
Power Electronics
The principle of capacitor charge balance: Derivation
19
Power Electronics
26
Power Electronics
Determination of inductor current dc component
8
Power Electronics
Actual output voltage waveform of buck converter
Buck converter containing practical low-pass filter
Actual output voltage waveform
v(t) = V + vripple(t)
Boost converter example
20
Power Electronics
wk.baidu.com
Boost converter analysis
21
Power Electronics
Subinterval 1: switch in position 1
22
Power Electronics
Subinterval 2: switch in position 2
Thought process in analyzing basic DC/DC converters
Basic operation principle (qualitative analysis)
– How does current flow during different switching states – How is energy transferred during different switching states