A
topology
of series active power filter (SAPF) based on a single phase half-bridge
cascaded multilevel inverter is proposed to compensate voltage harmonics of the
load connected to the point of common coupling (PCC). The main parts of the
inverter are presented in detail. Any voltage reference can be easily obtained
by a simple control with the proposed inverter. Therefore, the inverter acts as
a harmonic source when the reference is a non-sinusoidal signal. A prototype of
15-level inverter based SAPF is manufactured without using a parallel passive
filter (PPF) as it is intended to represent the compensation capability of the
SAPF by itself. The load connected to PCC whose voltage is non-sinusoidal is filtered
both in simulation and experimental studies. The validity of the proposed
inverter based SAPF is verified by simulation as well as experimental study.
Both simulation and experimental results show that the proposed multilevel inverter
is suitable for SAPF applications.
KEYWORDS:
1.
Active power
filter
2.
Multilevel
inverter
3.
Harmonic
compensation
4.
Half-bridge
cascaded
5.
Power quality
SOFTWARE: MATLAB/SIMULINK
CIRCUIT DIAGRAM:
Figure
1. The basic configuration of the proposed system.
Figure
2. Simulation results - Set I a) V pcc and VhPCC before compensation (50 V
Idiv), b) inverter and load
voltage
after compensation (50 V Idiv).
Figure
3. Simulaton results - Set 2 a) V pcc and V"pcc before compensation
(50 V ldiv), b) inverter and load voltage after compensation (50 V
Idiv).
CONCLUSION:
This
paper proposes a single phase half-bridge cascaded multi level inverter based
SAPF. The multi level inverter topology and operation principle is introduced.
With the proposed topology, the number of output levels can easily be increased.
Switching angles of the semiconductor devices used in the inverter are also
obtained by a simple method. A SAPF with the proposed inverter topology is
simulated under different harmonic distortion levels of PCC. The aim of the
simulation is to compensate the load voltage harmonics connected to PCc. In
addition to the simulations, the proposed SAPF prototype is designed. Using
this prototype, experimental study is performed. Microchip dsPIC30F6010 is
preferred as a controller in this prototype. It is a commercially available and
inexpensive microcontroller. The presentable results of the proposed system are
summarized as follows;
·
The THD values obtained from simulation
study is similar to experimental results.
·
The results of simulation and
experimental studies demonstrate the accuracy of the simulation study.
·
The THD values after compensation is
reduced to 2.88% and 3.07% by using the proposed inverter based SAPF. After
compensation, the waveform of load voltage is almost sinusoidal.
·
A highly distorted sinusoidal waveform
with a THD value of 24.12% is compensated with the proposed inverter based SAPF
and the THD value is reduced to 3.07%. This shows that the proposed inverter is
suitable for SAPF applications.
Both
simulation and experimental studies show the validity of the proposed inverter
as a SAPF.
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[3]
Z. Wang, Q. Wang, W. Yao, and 1. Liu, "A series active power filter adopting
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