This document discusses single-phase half-wave and full-wave controlled rectifiers with resistive and inductive loads. It explains that half-wave rectifiers have high ripple content and low frequency, while inductive loads allow current to continue flowing during reverse voltage halves due to stored energy. It also defines a freewheeling diode as one that commutates current away from the rectifier during reverse voltage and discusses its functions of preventing reverse voltage and allowing thyristors to block.

1. Single Phase
Controlled Rectifier

2. Principle of Phase-Controlled Converter Operation
(Single-Phase Half-Wave Controlled Rectifier)
With Resistive Load

5. This converter is not normally used in industrial applications
because its output as high ripple content and low ripple frequency.
Average Load Voltage

8. Single-Phase Half-Wave Controlled Rectifier With Inductive Load
When the supply voltage
reverse, the thyristor is
kept conducting due to
the fact that current
through the inductance
cannot be reduced to
zero.
During negative voltage half-cycle, current continuous to
flow till the energy stored in the inductance is dissipated in
the load resistor and a part of the energy is fed back
to the source. The effect of inductive load is increased in the
conduction period of SCR

10. Average Load Voltage
RMS Load Voltage
ᵦ: Extinction angle ‫ءافطالا‬‫ةيواز‬

11. 𝑉𝑟𝑚𝑠 =
𝑉2
𝑚
2π
2 𝑑𝑤𝑡
ᵦ
sin 𝑤 𝑡
α
=
𝑉2
𝑚
2π 2
(1 −cos2𝑤𝑡 ) 𝑑𝑤𝑡
ᵦ 1
α
= 𝑉 2
𝑚 1
(wt −1
sin2𝑤𝑡)
=
2π
2π 2 2
𝑉 2
𝑚 1 1
2
* ᵦ −α −2
,sin 2ᵦ −sin(2 α)-+
= 𝑽
𝒎 𝟐
𝝅
𝟐
ᵦ −𝜶 − 𝟏
,𝐬𝐢 𝐧 𝟐ᵦ − 𝐬𝐢 𝐧(𝟐𝜶)-

15. Freewheeling Diode
Freewheeling Diode: The diode which is used to commutate or transfer
or bypass load current away from the rectifier or SCR whenever
the load-voltage goes to a reverse state is called freewheeling
diode
Freewheeling diode is also called commutating diode, flywheel
diode, or bypass diode
Freewheeling diode serves two main functions:
1. It prevents reversal of load voltage except for small diode
voltage drop. It improves the power factor.
2.It transfer the load current away from the main rectifieror
SCR, thereby allowing all of its thyristors to region their
blocking states.

17. Performance Parameters of Rectifier

38. Single-phase full-wave controlled rectifier loaded
with highly inductive load:
This load represents a DC motor
E: back emf of armature of the DC motor= Kw ( K is constant and w motor speed)
E1/E2= W1/W2
R: armature resistance of the DC motor
L: armature inductance of the DC motor