HIGH BOOST RATIO HYBRID TRANSFORMER DC-DC CONVERTER FOR PHOTOVOLTAIC

MODULE APPLICATION

Under the guidance ofMr.K.KRISHNA KUMAR

PRESENTED BY: M.Anusha(11A21A0269)

L.Santosh kumar(11A21A0261)

M.Sai kumar(11A21A0262) M.Rohith singh(11A21A0263)

The main objective of this project is a high boost ratio hybrid transformer is increasing the efficiency of the converter for photovoltaic module applications.

Switching losses are reduced.

Able to implement maximum power point tracking(MPPT)

Current ripple and conduction losses are also reduced.

Output efficiency is greater than 96%

OBJECTIVES

The main drawback of the converter there

was a High input current ripple.

Output diode stresses are increased.

Light load efficiency of the converter is reduced because of switching losses are more dominent under light load condition.

PROBLEM IDENTIFICATION

Conventional systems

High step-up dc–dc converters using coupled-inductor and switched-capacitor techniques. (a) High-step coupled-inductor roboost dc-dc converter.(b) High step-up dc-dc converter with coupled-inductor and switched-capacitor.

PREVIOUS METHODS: 1.High step coupled inductor boost DC-DC converter 2. High step up DC-DC converter with coupled inductor and switched capacitor PROPOSED METHOD: High boost ratio hybrid transformer DC-DC converter

SOLUTION METHODS

The previous methods drawbacks are overcomed by using high boost ratio hybrid transformer DC-DC converter.

This method is advantageous for a two stage PCS.

By using this method, we achieve high level efficiency.

The inductive and capacitive energy can be transferred simultaneously to the high voltage DC bus.

Increasing the total delivered power and decreases the losses in the circuit.

Adding resonant inductor and reducing the capacitance of the switched capacitor in energy transfer path.

PROBLEM FORMULATION

DC-DC conversion stage using PCS.

ABOUT PREVIOUS METHODS

PCS accomplished single stage or double stage

The double-stage PCS consists of a dc–dc conversion stage that is connected to either a low power individual inverter.

a high-power centralized inverter have multiple inverters.

The high boost ratio dc–dc conversion stage of the PCS requires a high efficiency.

The high boost ratio DC-DC converter sare isolated or non isolated .

However, transformer-isolated converters tend to be less efficient and more expensive due to the increased manufacturing costs.

A non isolated dc–dc converter with a high boost ratio would be advantageous for a two-stage PCS

Because it can be easily integrated with current PV systems while reducing the cost and maintaining a high system efficiency

Combination of coupled inductor and boost converter:

DC-DC converter with coupled inductor and switched capacitor:

The above methods was proposed to increase the boost ratio without significant cost and efficiency penalties

Light load efficiency of the converter is reduced

because switching losses were more dominant under light load conditions.

In this leakage inductance is produced. It provides severe rigging and additional voltage stress on diode.

Ripple current increased

Now a days electric power is more important . Generating electric power from the

renewable energy sources. For that PV modules are increasing day by

day. The output of the PV module is in b/w 20-45v. By using non isolated step up transformer

DC-DC converter

EXPLANATION

High boost ratio non isolated dc–dc converter ,a clamp-mode couple-inductor buck–boost converter.

The converter’s leakage energy from the coupled-inductor was recycled reducing the losses of the system.

The output diode stress for this converter was similar to that of a traditional fly back converter, i.e., higher than the output dc bus voltage.

Another drawback of the converter was that there was a high input current ripple due to the fact that there was no direct energytransfer path when the MOSFET was OFF.

Conventional System

EQUIVALENT CIRCUIT

C= input capacitorHT= hybrid transformer with turns ratio 1:nS1=active MOSFET switchD1=clamping diodeCc=clamped capacitorLr=resonant inductorCr=resonant capacitor

OPERATING MODES

The important function of the dc–dc converter for PV applications is being able to implement maximum power point tracking (MPPT).

This paper presents a non isolated, high boost ratio hybrid transformer dc–dc converter with applications for low-voltage renewable energy sources.

The proposed converter utilizes a hybrid transformer to transfer the inductive and capacitive energy simultaneously.

achieving a high boost ratio with a smaller sized.

From the circuit , we calculate boost ratio: The first flux balance on the

magnetizing inductor of hybrid transformer

Vcc =Vin/(1-D) Second flux, according to the flux

balance on the resonant inductor. Vcr= nVin+Vcc =(n+1/(1-D))

The last flux balance that governs circuit is voltage second balance of the magnetizing inductor

VinD= (Vo-Vcr-Vin)/(1+n)*(1-D)

The boost conversion ratio Mb=Vo/Vin=n+2/n-D

BLOCK DIAGRAM

MODES OF OPERATION

SIMULATION CIRCUIT

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1-100

0

100

200

300

400

500

time(sec)

voltage(volts)

OUTPUT VOLTAGE

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

time(sec)

current(amps)

OUTPUT CURRENT

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.139

39.5

40

40.5

41

Time(sec)

voltage(volts)

INPUT VOLTAGE

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10

50

100

150

200

250

Time(sec)

power(watts)

OUTPUT POWER

DESIGN PARAMETERS

A high boost ratio dc–dc converter with hybrid transformer suitable for alternative dc energy sources with low dc voltage input is proposed in this paper.

The resonant conversion mode is incorporated into a traditional high step-up PWM converter with coupled-inductor and switched-capacitor.

FUTURE SCOPE

CONCLUSION

1. J.-S. Lai, “Power conditioning circuit topologies,” IEEE Ind. Electron. Mag., vol. 3, no. 2, pp. 24–34, Jun. 2009.2

2. S. B. Kjaer, J. K. Pedersen, and F. Blabber, “A review of single-phase grid-connected inverters for photovoltaic modules,” IEEE Trans. Ind. Appl., vol. 41, no. 5, pp. 1292–1306, Sep./Oct. 2005.

REFERENCES