INTERLEAVED QUADRUPLER DC –DC CONVERTER HIGH VOLTAGE GAIN WITH LOW VOLTAGE STRESS

INTERLEAVED QUADRUPLER DC –DC CONVERTER HIGH VOLTAGE GAINWITH LOW VOLTAGE STRESS

 Electrical and Electronics Project by Ravi Devani

ABSTRACT

In this paper interleaved quadrupler DC–DC converter high voltage gain with low voltage stress. Renewable energy is important for now a days and increases widely because of energy shortages and environmental contaminate problem in renewable energy system generate low output voltage and thus high step up dc-dc converter used to achieve high output voltage. In proposed system we are using three stage interleaved boost converter ,coupled inductor and voltage quadrupler concept used to reduced conduction losses, voltage spikes, voltage stress , balanced output voltage and achieve high output voltage without using extreme duty ratio and non- isolated operation.

Key words: high step up converter, three stage interleaved converter, quadrupler and coupled inductor and balancing capacitor.

INTRODUCTION

Nowadays, renewable energy is increasingly valued and employed worldwide because of energy shortage and environmental contamination. Renewable energy systems generate low voltage output, and thus, high step-up dc/dc converters have been widely employed in many renewable energy applications such fuel cells, wind power generation, and photovoltaic (PV) systems. Such systems transform energy from renewable sources into electrical energy and convert low voltage into high voltage via a step-up converter, which can convert energy into electricity using a grid-by-grid inverter or dc micro grid. Therefore, DC boost converter is needed to boost up a dc voltage. In dc boost converter.

Vo =Vin*1/1-D

However a duty ratio is larger means the output voltage is high. But the duty ratio is increasing means conduction time is high and it will arise voltage stress on switching devices, conduction loss is high. By the use of three interleaved stage interleaved boost converter and voltage quadrupler concept it will achieve high output voltage and reduce voltage stress and conduction loss.

Interleaved boost converter

Today interleaved converter is important techniques for power factor correction design is facing many problems. Power scalability, high power density and high entire load of efficiency. power scalability is necessary and cost effective approaches in the power factor correction design in that way power requirements growth is increases .The boost converter method D duty ratio is increasing very high then only we Attain high output voltage but the duty ratio increases means voltage stress occurs on switching devices. The conduction losses are also very high finally the efficiency is decreases. The filter capacitor is also added to reduce the current ripple. So the circuit size is very high and cost is also high. They are limited possibilities is available increasing power density due to EMI filter and increasing inductor size. So properly choosing the duty ratio then only attains low voltage stress and conduction losses and current ripple is also zero. The interleaved converter properly choosing duty ratio. The conduction losses and voltage stress is less and current ripple is also zero. The size of the circuits and cost is also zero.

  Electrical and Electronics Project by Ravi Devani

VOLTAGE QUADRUPLER

The addition of still another diode-capacitor section to the voltage Tripler produces an output four times the peak voltage. The circuit diagram is shown in below Figure.

 

Fig 1 . Voltage Quadrupler

 

Fig.2. Voltage Quadrupler Hardware

In such type of circuit C1 charges to Vm, through D1, C2 charges through D2, C3 and C4 charges through D4, C2, C3 and C4 charges to 2Vm. The 4Vm output is taken across C2 and C4.The ripple frequency is twice the input frequency. Theoretically there is no upper limit to the amount of voltage multiplication that can be obtain. But practically there is a limit the reason is that total amount of capacitance becomes large to maintain the desired d.c. output except extremely light loads.

APPLICATION

Voltage multipliers are used in high voltage, low current applications such as for accelerating purpose in a cathode ray tube. Generally these are used where both the supply voltage and load are maintained constant.

BLOCK DIAGRAM 

The input is PV cell. Photovoltaic cell is a renewable energy and it is 365 available sources in tamilnadu. In a single cell voltage is 0.5V. PV panel is connected into three stage interleaved boost converter. Interleaved boost converter with coupled inductor. Interleaved means more than one boost converter is connected into parallel. The output of the three stage interleaved boost converter is connected into a voltage quadrupler .PWM controller is used to triggering the switches.

The output of the voltage quadrupler circuit is connected into a DC load or DC micro Grid. The work of voltage quadrupler is increasing four times of the voltages.

CIRCUIT DISCRIPTION 

The proposed system is shown in Fig 1 shows the proposed three stage inter-leaved boost converter with coupled inductor and voltage quadrupler are connected in the circuits two balanced capacitor are connected in the circuits to achieve balanced output voltage. In existing system use two stage inter-leaved circuits and voltage doublers the conduction period of two stage inter-leaved switches used 50%.the voltage stress is high compare two proposed system and the output of the two stage inter-leaved circuits connected to voltage doublers circuits to achieve high output voltage. In proposed system we are use three stage inter-leaved circuits is 33% for three switches. So it reduces switching stress and conduction loss. The output of the three stage inter-leaved boost converter is connected to voltage quadrupler circuit voltage quadrupler means the output voltage is increase four times. Now we can achieved high voltage gain .Fig. 1shows the circuit diagram of the proposed system drawn using MATLAB simulation tool. It consists of a dc source from PV panel. Three stage interleaved boost converter with coupled inductor and voltage quadrupler circuits are used. The switching of the PWM inverter can be effectively controlled by the output. The balanced capacitor is connected to achieve balanced output voltage.

Fig.3. Proposed system inter-leaved converter

Mode.1:In a circuit contains three switches S1,S2,S3 .In mode 1 condition switch 1 is ON condition on that time L1,L2, L3 inductance are stored on energy. Switch 1 is short circuit in previous mode capacitance stored energy flowing through diode D2 after the energy is flowing to C1, C2 the load.

             

Fig.4.Equivalent circuit of all modes

The L2 inductance stored energy flowing through diode D4 and D6 through the load. The L3 inductance stored energy flowing through diode D5 and d7 through the load. The coupled inductance is used in the circuits so the energy is increasing twice the times it’s flowing to C4, C1 and C2 capacitor. Balancing capacitor C1, C2 is used in the circuit to achieving balanced output voltage.

  Electrical and Electronics Project by Ravi Devani

Mode2: In mode 2 condition switch 2 is ON condition on that time L1, L2, L3 inductance are stored on energy. In previous mode switch 1 is OFF condition. Switch 2 is short circuit in previous mode capacitance stored energy flowing through diode D7 to the load. The L1 inductance stored energy flowing through diode D1 and D7 through the load. The L3 inductance stored energy flowing through diode D5 and d7 through the load. The coupled inductance is used in the circuits so the energy is increasing twice the times it’s flowing to C4, C1 and C2 capacitor. Balancing capacitor C1, C2 is used in the circuit to achieving balanced output voltage.

Mode 3: In mode 3 condition switch 1 is ON condition on that time L1, L2, L3 inductance are stored on energy. In previous mode operation switch 2 is OFF condition. Switch 3 is short circuit in previous mode capacitance stored energy flowing through diode D5 and d7 to the load. The L1 inductance stored energy flowing through diode D1 and D7 through the load. The L2 inductance stored energy flowing through diode D4 and D6 through the load.The coupled inductance is used in the circuits so the energy is increasing twice the times it’s flowing to C4, C1 and C2 capacitor. Balancing capacitor C1, C2 is used in the circuit to achieving balanced output voltage.

SIMULATION RESULTS AND DISCUSSION 

The proposed converter 18-v input voltage and 158-v output voltage fig 1 is chosen. The switching frequency is used in the circuit is 50 kHz, the duty ratio of S1, S2, S3 is 0.33 so it is used to reduce voltage stress and current stress and finally it reduce conduction losses. The output voltage is increases up to 158v after it attains transient states on time period 0.6sec. The conduction losses on state voltage reaches attain 0.1-v the conduction of current is 6.85A.The duty ratio timing period is o.33. 

Fig.5. Proposed input voltage

Fig.6. Proposed hardware input voltage

Fig.7. Hardware output voltage

Fig8. Output voltage and current

Conduction losses for proposed system

i/p voltage =17 v

o/p voltage =158v

power = V*I=158*3.165

P = 500.07W

Pon = Von Io Ton

Von = on-state voltage

Io = conducting of current

Ton = conduction during the ON time interval

Pon = 0.1*6.8*0.33

Pon = 0.224W

CONCLUSION

In this paper interleaved quadrupler voltage DC-DC converter was discussed and it has achieved high voltage gain and reduced voltage stress, current ripple and conduction losses with the help of three stage inter-leaved boost converter with voltage quadrupler circuits and to get a balanced output voltage connection of balanced capacitor finally the input voltage is 18v and the output voltage is 158v. The conduction losses is 0.224w for 500.07w power.

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 Electrical and Electronics Project by Ravi Devani