The document discusses different types of resonant pulse inverters. It begins by explaining the disadvantages of traditional pulse-width modulation controlled converters, such as high switching losses and electromagnetic interference. It then introduces resonant pulse converters which minimize these issues by forcing the voltage and current to zero during switching. The document outlines various resonant converter topologies, including series and parallel resonant inverters as well as classes of converters that achieve zero-voltage or zero-current switching. It provides examples of half-bridge and full-bridge configurations for series resonant inverters with both unidirectional and bidirectional switches. Finally, it briefly discusses the operation of parallel resonant inverters.

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RESONANT PULSE INVERTERS
Dr. A. Ravi
Professor/EEE
FRANCIS XAVIER ENGINEERING COLLEGE
TIRUNELVELI- India

2. � To get the desired output voltage or current , the
switching devices in converters are controlled by with
a pulse-width-modulation (PWM) control.
� Hence the devices are undergone with high switch
high di/dt value also high voltage stresses resulting
Power loss of a devices.
� This power losses are increasing with switching
frequency.
� The electromagnetic interference is also produced due
to high di/dt and dv/dt in the converter waveforms.
2
WHY RESONANT PULSE CONVERTER- INTRODUCTION

3. � The disadvantages of PWM control can be
eliminated or minimized if the switching
devices are turned “on” and “off” when the
voltage across a device or its current becomes
zero.
� The voltage and current are forced to pass
through zero crossing by creating an LC-
resonant circuit, thereby called a resonant
pulse converter.
3
WHY RESONANT PULSE CONVERTER- INTRODUCTION

4. � Series resonant inverters
� Parallel resonant inverters
� Class E resonant converter
� Class E resonant rectifier
� Zero-voltage-switching (ZVS) resonant
converters
� Zero-current-switching (ZCS) resonant
converters
� Two-quadrant ZVS resonant converters
� Resonant dc-link inverters 4
RESONANT PULSE CONVERTER- TYPES

5. � The series resonant inverters produce a near
sinusoidal output voltage and the output
current depends on the load impedances.
� The parallel resonant inverter produces a
near sinusoidal output current and the output
voltage depends on the load impedances.
� These types of inverters are used for producing
high-frequency output voltage or current and
are often used as an intermediate between a dc
source and a dc power supply.
5
RESONANT PULSE CONVERTER-

6. � depending on the connections of the switching devices
and load. The series inverters may be classified into
two categories:
� 1. Series resonant inverters with unidirectional
switches
� 2. Series resonant inverters with bidirectional
switches
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SERIES RESONANT INVERTERS

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SERIES RESONANT INVERTERS WITH
UNIDIRECTIONAL SWITCHES
The series resonant
circuit formed by L, C,
and load (assumed
resistive) must be
Underdamped. That is,

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SERIES RESONANT INVERTERS WITH
UNIDIRECTIONAL SWITCHES
Disadvantages: The power flow from the dc supply is discontinuous

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SERIES RESONANT INVERTERS WITH
UNIDIRECTIONAL SWITCHES
 An improvement of the basic
inverter can be made if inductors
are closely coupled, as shown here.
 When Q1 is turned on and current
i1(t) begins to rise, the voltage
across L1 is positive with polarity as
shown.
 The induced voltage on L2 now
adds to the voltage of C in reverse
biasing Q2; and Q2 can be turned off.
The result is that firing of one
transistor turns off the other, even
before the load current reaches
zero.

10.  The drawback of high-pulsed
current from the dc supply can
be overcome in a half-bridge
Configuration where L1 = L2
and C1 = C2.
� The power is drawn from the
dc source during both half-
cycles of output voltage.
� One-half of the load current is
supplied by capacitor C1 or C2
and the other half by the dc
source 10
(i) Half-bridge series resonant inverter.
Series Resonant Inverters with Unidirectional Switches

11. � When Q1 and Q2 are turned
on, a positive resonant
current flows through the
load;
� and when Q3 and Q4 are
turned on, a negative load
current flows. The supply
current is continuous, but
pulsating.
� The resonant frequency and
available dead zone depend
on the load. 11
(ii)Full-bridge series resonant inverter.
Series Resonant Inverters with Unidirectional Switches

12. � For the resonant inverters with
unidirectional switches, the power devices
have to be turned on in every half-cycle of
output voltage.
� This limits the inverter frequency and the
amount of energy transfer from the source to
the load. In addition, the devices are
subjected to high peak reverse voltage.
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Series Resonant Inverters with Unidirectional Switches

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Series Resonant Inverters with Bidirectional Switches
• When device Q1 is turned on, a resonant pulse of current flows and
Q2 is self-commutated at t = t1.
• However, the resonant oscillation continues through diode D1 until
the current falls again to zero at the end of a cycle.

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Series Resonant Inverters with Bidirectional Switches
Half-bridge series inverters with bidirectional switches.

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Full-bridge series inverters with bidirectional switches.
Series Resonant Inverters with Bidirectional Switches

16. � A parallel resonant inverter is the dual of a series
resonant inverter.
� It is supplied from a current source so that the circuit
offers a high impedance to the switching current.
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Parallel Resonant Inverters

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Parallel Resonant Inverters
Equivalent circuit
Equivalent circuit

18. REFERENCE
18
Power Electronics Devices, Circuits, and
Applications
FOURTH EDITION
Muhammad H. Rashid

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