International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 5, Issue 5, May2015)
Design and Simulation of H-Bridge Converter with Additional
Switch Legs Using Different Control Techniques
Meghana A. Deshpande1, Sahebrao N. Patil2
1,2
Department of Electrical Engineering, Savitribai Phule Pune University, Pune, India
This converter topology uses the grid connected
converter without the use of galvanic isolation.
In case PV power conditioning system is employed to
inverter, stray capacitance between the PV panel and the
earth ground affects the common mode noise [2] [5]. The
common mode current reduces the efficiency of power
conversion stage, affects the quality of grid current,
deteriorate the electric magnetic compatibility and give rise
to the safety threats.
Converter circuits consist of semiconductor switching
devices which produce significant harmonic voltages as
they chop voltage waveforms during the transition between
the conducting and cutoff stages [6]. The bridgeless boost
rectifiers consist of semiconductor switching devices
between the grounds of input and output terminals [4] [5]
[6]. They are considered as a major contributor to the
power system harmonics because of high common mode
voltage [7]. The common mode current in any converter is
produced when the voltage levels of the input and output
terminals with respect to the earth ground are not same.
Therefore by making the voltage levels of the input and
output grounds same it is possible to reduce common mode
current and consequently common mode noise by
connecting input and output terminals by solid
connection[3].
In the proposed study the triggering signals to H-bridge
converter are designed by using the Sinusoidal Pulse Width
Modulation (SPWM) technique to reduce the common
mode noise [8]. The main focus of this paper is on the Hbridge converter with different control techniques including
average current control [9] and Sinusoidal Pulse Width
Modulation (SPWM) control. These control techniques are
studied and compared with each other based on Total
Harmonic distortion (THD).
Abstract— This paper presents the design and
implementation of H-bridge converter with additional switch
legs (HA converter) which acts as AC-DC rectifier as well as
DC-AC inverter. In this topology a solid connection is
provided between the grounds of the input and output
terminals, which reduces common mode noise and makes the
converter suitable for PV PCS in dc distribution system or
stand-alone power system. This paper presents the
comparative evaluation of the performance of the two main
control techniques for H-bridge converter with additional
switch legs for reducing THD by reducing the common mode
noise. Common-mode noise signals are high frequency signals
which are created as a result of different voltage levels of
input and output terminal with respect to ground terminal.
SPWM voltage controller and average current controller are
considered here. Harmonic analysis of these two control
techniques is performed using FFT analysis of Simulink in
MATLAB. Lower order harmonics are reduced using
sinusoidal PWM technique. EMI filtering circuits are also
used to get better results. As unwanted EMI is at much higher
frequencies than normal signals, the EMI filter blocks or
shunts unwanted higher frequencies. The main objective of
this scheme is to reduce total harmonic distortion at the input
side of the rectifier and output side of the inverter. The
simulation results of both the techniques have been
demonstrated.
Keywords—H-bridge converter, average current control,
Sinusoidal pulse width modulation (SPWM), common mode
current, Total harmonic distortion (THD)
I.
INTRODUCTION
Global energy consumption is increasing continuously.
Due to depletion of conventional, fossil resources the
renewable energy sources are becoming more popular to
satisfy the demand for electric power [1]. The power
converters in DC distribution system such as ac-dc
rectifiers and dc-ac inverters play an important role in
optimizing the use of the renewable energy and improving
system stability. The outputs of the renewable energy
sources are fluctuating. To make these outputs stable and to
achieve proper cooperation with the conventional ac utility
grid, various power conversion topologies are employed.
Transformers less topology of converters are becoming
more popular because of their greater efficiency, smaller
size, and lower costs [2].
II.
H-BRIDGE CONVERTER
The H-Bridge converter with additional switch legs is a
bidirectional converter. Bidirectional power conversion is
possible according to the switch operation. In this converter
common mode noise and electromagnetic interference can
be reduced by providing solid connection between the input
and output terminals.
167
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 5, Issue 5, May2015)
This H-Bridge converter can handle the bidirectional
power flow shown in fig.1.The power flows from source v1
to v2 and also from v2 to v1 by proper selection of switches.
The relationship between the average line current and
the average inductor current per switching cycle is used to
generate control signal.
During the states 1 and 2 combination i.e. during
positive half cycle of input ac voltage, the average inductor
current in a unit switching cycle, is equal to the average
line current because the inductor is connected in series with
the ac voltage source. But during negative half cycle, the
average line current is not equal to the average inductor
current but equal to the average switch current of Q2.
Therefore, coefficient change or correction factor should be
multiplied to the control loop to properly shape the line
current. Therefore during states 1 and 2 combination
inductor current is
I L12 = I L = I m Sin wt
Fig 1.H-bridge converter for bidirectional flow
III.
PRINCIPLE OF OPERATION
(1)
Where IL12=Inductor current during states 1 and 2
The operation of the H-Bridge converter with four
switches as shown in fig.1 is explained below. It consists of
four states of operation for each ac line voltage polarity.
During positive voltage polarity, in the first state of
operation, only switches Q1 and Q4 operates and energy is
stored in the inductor from voltage source v1. In the second
state of operation, Q1 and Q3 operate and in this state
energy is transferred from v1 to v2 through the inductor. In
the third state, Q2 and Q4 operate and the energy stored in
the inductor is discharged to the load v2.In the fourth state
of operation only the switches Q2 and Q3 operates. Energy
in the inductor is circulated. For negative ac voltage, the Hbridge converter has similar four modes such as modes 5,
6, 7, and 8 except that the direction of the inductor current
is reversed.
IL= Average line current
And during states 5 and 3 combination,
 V1 
I L53 = I L = 1 
 I m Sinwt
 V2 
(2)
Where IL53=Inductor current during states 5 and 3.
IL= Average line current
V1 = Supply voltage
V2 = Output voltage
A. AC-DC Rectifier
During the positive half cycle, states 1 and 2 are selected
and during negative half cycle, states 5 and 3 are selected
so that the power from the ac voltage source is rectified and
delivered to the dc voltage source. By choosing this
combination of states unnecessary switching of Q1 and Q4
can be avoided that reduces switching losses.
B. DC-AC Inverter
During the positive half cycle, states 6 and 5 are selected
and during negative half cycle, states 7 and 1 are selected
when the power flows from dc to ac voltage source .
IV.
Fig- 2. Simulation model of average current control technique
AVERAGE CURRENT MODE CONTROL
Average current mode control is used to shape the ac
line current to minimize its distortion.
168
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 5, Issue 5, May2015)
V.
Table-II
INVERTER PARAMETERS
SINUSOIDAL PULSE WIDTH MODULATION
Pulse width-modulation (PWM) converters in
distribution systems are very effective in terms of
performance, for elimination of harmonic distortion, power
factor correction, voltage regulation and flicker
compensation. Sinusoidal PWM is a technique where the
sinusoidal waveform or modulation signal is compared
with a very high frequency triangular or carrier signal to
obtain the switching pulses for the device.
In this control technique the load voltage is compared
with the reference voltage and error obtained is fed to PI
controller. Then the signal generated from PI controller
which is sinusoidal reference signal is compared with high
frequency triangular signal to generate gating signals.
Parameters
Values
Input AC voltage
400V
Supply Frequency
60Hz
Common mode capacitor
330nF
Switching Frequency
20kHz
Fig- 4. Simulation model of H-bridge rectifier with additional switch
legs using average current mode control
Fig- 3.Simulation model of Sinusoidal pulse width modulation
VI.
SIMULATION RESULTS
Simulation of single phase H-bridge converter using
average current mode control and sinusoidal pulse width
modulation is carried out with the help of
MATLAB/SIMULINK. Comparison of harmonic analysis
of average current mode control and sinusoidal pulse width
modulation are carried out to observe the improvement in
input current of rectifier and output voltage of inverter.
Table-I
RECTIFIER PARAMETERS
Parameters
Values
Input AC voltage
230V
Supply Frequency
60Hz
Common mode capacitor
330nF
Switching Frequency
36kHz
Fig-5.Input voltage waveform for the average current mode controller
169
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Fig-9.Input voltage of rectifier for the sinusoidal pulse width
modulation
Fig-6.Input current waveform for the average current mode
controller
Fig-10.Input current of rectifier for the sinusoidal pulse width
modulation
Fig-7. Harmonic spectrum of input current for average current mode
controller
Fig-11..Harmonic spectrum of input current for sinusoidal pulse
width modulation
Fig-8.Simulation model of H-bridge rectifier with additional switch
legs using sinusoidal pulse width modulation
Fig-12. Simulation model of H-bridge inverter with additional switch
legs using average current mode control
170
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 5, Issue 5, May2015)
Fig-16.Output voltage of inverter for the sinusoidal pulse width
modulation
Fig-13.Output voltage of inverter for the average current mode
controller
Fig-17.Harmonic spectrum of output voltage for sinusoidal pulse
width modulation
Fig-14. Harmonic spectrum of output voltage for average current
mode controller
TABLE-III:
Comparison Of Control Techniques for rectifier
H-bridge rectifier
Control method
% Current THD
Average current
control
4.21
Sinusoidal pulse
width modulation
2.86
TABLE-IV:
Comparison Of Control Techniques for inverter
H-bridge inverter
Fig-15.Simulation model of H-bridge inverter with additional switch
legs using sinusoidal pulse width modulation
171
Control method
%Voltage THD
Average current
control
0.08
Sinusoidal pulse
width modulation
0.06
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 5, Issue 5, May2015)
VII.
[3]
CONCLUSION
The harmonic spectrums for the two control methods are
compared for input current of H-bridge rectifier and output
voltage of H-bridge inverter. From simulation results it is
observed that sinusoidal PWM technique is more effective
in reducing the common mode noise which in turn reduces
harmonics in supply current in case of rectifier and in
output voltage in case of inverter as compared to average
current mode control technique. This reduces
electromagnetic interference, reduces harmonic distortions
and improves the quality of waveform.
[4]
[5]
[6]
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