Converters

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Converters or DC Chopper
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Step-down Chopper
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Type of Choppers Controlled
Constant Frequency Operation
Variable Frequency Operation
Pulse Width Modulation
Frequency Modulation
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Step-down Chopper (RL)
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Mode 1
Mode 2
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Mode 1
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Mode 2
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Step-up Chopper
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Transfer of Energy
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Chopper Classification
Class A Load current flows into load. Both the
load voltage and the load current are positive.
This is a single quadrant chopper or rectifier.
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Chopper Classification
Class B Load current flows out of load. Load
voltage is positive but load current is
negative. This is also a single-quadrant
chopper but operates in the second quadrant and
is said to be operated as an inverter.
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Chopper Classification
Class C Load current is either positive or
negative. Load voltage is positive. This is
known as a two-quadrant chopper. Class A and B
can be combined to form a class C. Class C can
operate either as a rectifier or inverter.
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Chopper Classification
Class D Load current is positive. Load voltage is
either positive or negative. Class D can also
operate either as a rectifier or inverter.
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Chopper Classification
Class E Load current is either positive or
negative. Load voltage is also either positive or
negative. This is known as a four-quadrant
chopper.
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Switching Mode Regulators
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Buck Regulators
Boost Regulators
Buck-Boost Regulators
Cuk Regulators
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Buck Regulators
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Buck Regulators
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Inductor current rises
Inductor current falls
Peak-to-peak ripple current
Average Output Voltage
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Average input current
Switching period T
Peak-to-peak ripple current
Peak-to-peak ripple voltage for capacitor
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The buck regulator has an input voltage of VS
12V. The required average output voltage is va
5 V and the peak-to-peak output ripple voltage is
20 mV. The switching frequency is 25 kHz. If the
peak-to-peak ripple current of inductor is
limited to 0.8 A, determine (a) the duty cycle k,
(b) the filter inductance L, and (c)the filter
capacitor C.
the duty cycle k
L
C
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Boost Regulator
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Inductor current rises
Inductor current falls
Peak-to-peak ripple current
Average Output Voltage
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Average input current
Switching period T
Peak-to-peak ripple current
Peak-to-peak ripple voltage for capacitor
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The buck regulator has an input voltage of VS
5V. The required average output voltage is Va
15 V and the average load current Ia0.5A. The
switching frequency is 25 kHz. If L 150 uH and C
220uF, determine (a) the duty cycle k, (b) the
ripple current of inductor , and (c)the filter
capacitor C.
duty cycle k
C
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Chopper Classification
Class B Load current flows out of load. Load
voltage is positive but load current is
negative. This is also a single-quadrant
chopper but operates in the second quadrant and
is said to be operated as an inverter.
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Inverters
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Single-Phase Half-Bridge Inverter
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Single-Phase Bridge Inverter