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Chapter Two Series and Parallel operation Series and parallel combination of diodes are essentially for handling the high voltage and high current necessary in such applications. Steady-state and transient voltages must be equally shared when diodes are connected in series. When diodes are connected in parallel, each diode must share the total load current equally, both under transient and under steady state conditions.
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POWER ELECTRONICS
Instructor: Eng. Jalal Al Roumy
The Islamic University of GazaFaculty of EngineeringElectrical Engineering Department
الرحمن الله بسمالرحيم
EELE 5450 — Summer 2012
Lecture 4
Chapter Two
Series and Parallel operation
In many applications, the power handling capability of a single power diode is not sufficient. (HVDC applications).
Chapter Two
Series and Parallel operation
Series and parallel combination of diodes are essentially for handling the high voltage and high current necessary in such applications.
Steady-state and transient voltages must be equally shared when diodes are connected in series.
When diodes are connected in parallel, each diode must share the total load current equally, both under transient and under steady state conditions.
Chapter Two
Series operation of diodes
Series-Connected Diodes
Chapter Two
Series operation of diodes
Series-Connected Diodes with Voltage Sharing
Chapter Two
Series operation of diodes
Is=Is1+IR1=Is2+IR2, IR1=VD1/R1, IR2=VD2/R2
Chapter Two
Series operation of diodes
More than two diodes
Chapter Two
Series operation of diodes
Series-Connected Diodes with Dynamic Voltage Sharing
Chapter Two
Example:Find the diode voltages if R1 = R2 =R = 100 kFind the voltage sharing resistances R1 and R2 for equal diode voltages
1 25 30 35S S SV kV I mA I mA
Chapter Two
Example: Find the diode voltages if R1 = R2 =R = 100 k1)Vd1=2750V2)Vd2=2250V
Find the voltage sharing resistancesR1 and R2 for equal diode voltages1)Let R1=100k2)R2= 125K
Chapter Two
Parallel-Connected Diodes
End of Lecture
