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Ac–Ac Converter Based On Switched-Capacitor Using Step-Up and Step
Down Converter
P.Gopala Krishna1, M. Sreenivasulu Reddy2
1
M.Tech Student of JNTU, ANANTHAPUR, AP-India,[email protected]
2
Assistant Professor, EEE Dept, JNTU, ANANTHAPUR, AP-India
continuously increasing and is today extraordinary the
supply. The switched-capacitor (SC) converters are an
ABSTRACT—Now-a-days the novel ac–ac static
awfully necessary analysis topic for numerous years,
power converter Based on the switched-capacitor
primarily in regard to non-isolated dc–dc static power
(SC) principle, fictional to interchange the modern
conversion. Some applications that already have the benefit
autotransformer in industrial and residential
of the SC principle embrace power provides for mobile
Applications. The source of operation, to the
electronics systems, electric vehicles, battery equalizer
qualitative and quantitative analysis, the design
circuits, voltage-balancing circuits for multilevel inverters,
methodology, associated an example are described
etc. As SC power converters are composed only of
during this paper. The main benefits of the
proposed ac–ac converter are the absence of
capacitors and switches, without magnetic devices, they will
accomplish significant size reduction compared with the
converters typically utilized in conventional switched-Mode
magnetic components, the strain voltages in all
elements being capable half of the high-side
power supplies. Moreover, the behavior of those circuits is
represented by straightforward equivalent circuits and it's
voltage, the mutual reference among the input and
attainable to fabricate these converters on a semiconductor
output voltages, the utilization of one SC leg, the
IC chip.
power to be bidirectional.
A recent publication extended for the first time the
KEYWORDS—bidirectional, AC–AC converter,
switching capacitor principle to ac–ac static conversion,
switched capacitor (SC).
wherever a short analysis and experimental results for a
I.
step-down/step-up converter with rated power of 600W,
INTRODUCTION
During the world, it's common to search out industrial and
domestic appliances that employment with completely
different Voltages from those accessible on the electrical
grid and therefore the solution answer are the utilization of a
low-power/low-voltage
autotransformer.
However,
like
several electromagnetic transformers, the autotransformer
efficiency is poor and it produces considerable perceptible
noise. Moreover, the world demand for copper, utilised
within the autotransformer winding construction, has been
high-side voltage of 220Vrms , low-side voltage of 110Vrms
, line frequency of 60 Hz, and switch frequency of 50
kilohertz were conferred. The most characteristics of the
converter are the strain voltages altogether elements being
adequate to half the high-side voltage, the differential output
voltage, the utilization of two SC legs, and eight
unidirectional switches. The results conferred in are
promising associated show that the use of associate SC in an
ac–ac converter will contribute with new and efficient
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solutions for the ac–ac space, as, as an example, in lowpower/low-voltage systems aimed toward exchange the
standard
autotransformer
in
industrial and
domestic
applications.
The purpose is to introduce a new SC-based ac–ac
static power converter topology. The most characteristics of
the projected ac–ac converter that {are also|also are|are}
present in are the absence of magnetic components and also
the stress voltages on the switches being adequate to half the
high-side
voltage.
Additionally,
there
are
the
new
characteristics of getting a standard reference between input
and output voltages, no dc element within the capacitance
voltages, and also the employment of one SC leg and four
bidirectional switches. Detailed analysis of the converter,
Fig. 1. Proposed SC ac–ac converter: (a) step-down
configuration, (b) step-up configuration
equivalent circuits, the design methodology, as well as
experimental results is informed herein.
In this topology, one half the high-side voltage (vH /2) is
applied to C2 and C3. Capacitance C1, being connected to
II. PROPOSED SC AC–AC CONVERTER
C2 and when this to C3 in every switch amount, equalizes
The proposed SC ac–ac converter is specified
their voltages to VL = vH /2. Each bidirectional switch
in Fig. 1. This converter functions as a step-down converter
series resistance is taken into account, and despite being
one time configured as shown in Fig. 1(a) or as a step-up
required for the capacitor charge/discharge method, they
converter when organized according to Fig. 1(b). The only
additionally cause losses. These losses are decreased for D =
distinction is that the points where the supply and therefore
0.5, as are going to be mentioned in a later section, that is
the load are connected need to be inverted. The circuit has
the proposed duty cycle.
four bidirectional switches described as S1, S2, S3, and S4
and three capacitors described asC1, C2, and C3. Fig. 1(c)
and (d) shows the proposed gate signals and the practical
implementation of a bidirectional switch victimization two
conventional MOSFETs, severally.
Fig. 1. Proposed SC ac–ac converter: (c) gate drive
signals, and (d) bidirectional switch model and its
practical implementation using two MOSFETs.
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Operating Modes:
These are the different types of operating modes
that are classified into two cycles they are: Positive halfcycle of the grid voltage: (a) First stage. (b) Second stage.
Fig. 2. Topological stages for step-down configuration.
Negative half-cycle of the grid voltage: (c) first stage. (d)
second stage.
Fig. 2. Topological stages for step-down configuration.
Positive half-cycle of the grid voltage: (a) first stage. (b)
second stage.
Second stage
Second stage starts once switches S2 and S4
are turned ON. Primarily, the power supply collects energy
from the circuit, capacitance C2 discharges, and capacitance
First stage
C3 charges till their currents reach zero (Δt2A).After this,
First stage starts when switches S1 and S3 are
turned ON. Capacitance C2 discharges and capacitance C3
charges throughout the primary a part of this stage
(Δt1A).When their currents reach zero, C2 starts to charge
and C3 starts to discharge till the tip of the stage
(Δt1B).Capacitor C1 charges throughout this stage and
therefore the power supply vH delivers energy to the circuit.
Switches S1 and S3 are turned OFF at the tip of the primary
stage. This topological stage is shown in Fig.2. (a).
Negative half-cycle of the grid voltage (c) First stage. (d)
Second stage.
the power supply delivers energy to the circuit, capacitance
C2 charges and capacitance C3 discharges till the tip of the
stage (Δt2A).Capacitor C1 discharges throughout this stage.
Switches S2 and S4 are turned OFF at the tip of the second
stage. This topological stage is shown in Fig. Fig.2. (b)
when the second stage, another switch period starts from the
primary stage. Within the negative half-cycle of the grid, the
converter has similar operation stages with totally different
current directions, as will be seen in Fig.2. (c) and (d).
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III
.SIMULATION RESULTS
A simulation design closed loop system as shown in fig is
A simulation design step down converter
implemented in MATLAB SIMULINK with the help of
system as shown in fig is implemented in MATLAB
MOSFET Switches and switched capacitors we get desired
SIMULINK with the help of MOSFET Switches and
output voltage level step down voltage waveform.
switched capacitors we get desired output voltage level step
down voltage waveform.
Fig.5. Step up SC ac to ac converter
Fig. 3. open loop system of SC ac to ac Converter
Fig.6. Step up converter output wave form.
Fig.4. Step down converter output voltage waveform
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EXPECTED INPUT AND EXPECTED OUTPUT
[2] A. Ioinovici, “Switched-capacitor power electronics
circuits,” IEEE Circuits Syst. Mag., vol. 1, no. 3, pp. 37–42,
OUTPUT
CONVERTER INPUT
TYPE
Step Up
[3] I. Batarseh, G. Zhu, H. Wei, and A. Ioinovici, “A new
Vac
=
Vac = 220V(rms)
110V(rms)
Step Down
Third Quarter 2001.
Vac
switched-capacitor dc-dc converter with improved line and
load regulations,” in Proc. IEEE Int. Symp. Circuits Syst.,
=
Vac = 110V(rms)
1999.
220V(rms)
[4] D. Maksimovic and M. S. Makowski, “Performance
IV. CONCLUSION
A novel ac–ac static power converter established
limits of switched capacitor dc-dc converters,” in Proc. 26th
Annu. IEEE Power Electron. Spec. Conf., 1995.
on the SC principle has been proposed. The following
conclusions can be drawn after the imaginary analysis and
[5] S. R. Sanders and M. D. Seeman, “Analysis and
the experimental results reported in this paper the proposed
optimization of switched capacitor dc-dc converters,” IEEE
ac–ac static power converter works only capacitors and
Trans. Power Electron., Mar. 2008.
switches
the converter employs a single SC and has a
common reference in the middle of output and input
[6] S. Tapuchi, B. Axelrod, A. Ioinovici, and Y. Berkovich,
voltages the converter functioning in open loop through a
“Single stage single-switch switched-capacitor buck/buck-
constant duty cycle of 0.5 presents better voltage regulation
boost-type converter,” IEEE Trans. Aerosp. Electron. Syst.,
than its autotransformer counterpart with the same
Apr. 2009.
specifications the topology does not require complex control
algorithms, the conversion efficiency is high, and the power
[7] C. Shin-Ming, A. Ioinovici, L. Tsorng-Juu, Y. Lung-
factor is close to 1 for rated power; the circuit can operate
Sheng, and C. Jiann-Fuh, “A single switch boost-flyback
as a step-down converter (static gain of 0.5) or a step-up
dc-dc converter integrated with switched-capacitor cell,” in
converter (static gain of 2), and in both modes, only one-half
Proc. IEEE 8th Int. Conf. Power Electron., May/Jun. 2011.
of the high-side voltage is applied to the switches and the
capacitors the theoretical analysis results were corroborated
[8] Y. Berkovich, B. Axelrod, and A. Ioinovici, “A boost-
by the experimental results the proposed converter is a
switched capacitor inverter with a multilevel waveform,” in
potential candidate for substituting the conventional
Proc. Int. Symp. Circuits Syst., 2004, vol. 5, pp. V-884–V-
autotransformer in low-power applications.
887.
REFERENCES
[1] R. L. Andersen, T. B. Lazzarin, I. Barbi, and G. B.
Martins, “A 600 W switched-capacitor ac-ac converter for
220 V/110 V and 110 V/220 V applications,” IEEE Trans.
Power Electron., Dec. 2012.