**DESIGN AND STEADY STATE ANALYSIS OF PARALLEL RESONANT DC-DC CONVERTER FOR **** HIGH VOLTAGE POWER GENERATOR**

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*Abstract*

A novel voltage-doubling circuit with parallel resonant DC-DC converter is proposed. The converter consists of full-bridge inverter, resonant tank, high frequency high voltage transformer, and voltage-doubling circuit. In the high voltage applications, low output voltage ripple has been given much attention. The output voltage step-up ratio is increased by two parts. One is a high frequency high voltage transformer and the other is a voltage-doubling circuit. The novel voltage-doubling circuit can not only reach a higher output voltage but also reduce output ripple to a lower level than the conventional one. Therefore, while maintaining the same output voltage, the transformer’s turn ratio can be reduced compared with the conventional voltage-doubling circuit. The output power can be adjusted by the phase-shift control technique. In addition, combining this technique with the parallel resonant tank can make all the switches achieve zero voltage turn on (ZVS). The operating principles, steady-state analysis, and the parameter designs are discussed in this paper. Finally, a prototype circuit with 400V input voltage, 40kV output voltage, and 300W output power is developed in the laboratory to verify the performance of the proposed converter.

**EXISTING SYSTEM: **

The full-bridge DC-DC converter and phase-shift control technique are widely used in high voltage DC power supply. The adopted conventional full-bridge DC-DC converter usually doesn’t contain resonant tanks. However, the voltage across the transformer’s primary side will ring and cause the consumption of the power converter to increase and the stress of the circuit components to increase. Two basic topologies of resonant circuits are commonly used in the full-bridge DC-DC converter, resonant circuits including the series resonant circuit and parallel resonant circuit. Both of the topologies can make all the switches in the circuit achieve zero voltage switching (ZVS) or zero current switching (ZCS). Therefore, it can reduce the voltage or current stress of the switches and increase the whole efficiency of the converter. Normally, the DC-DC resonant converter can be examined in the time domain or in the frequency domain. It was straightforward for a DC-DC resonant converter to be analyzed by the frequency domain in most of the literature. However, the equivalent circuit in frequency domain was ignored in the equivalent capacitor of the voltage-doubling circuit. The steady state analysis of the RC load was proposed in. In this paper, the waveform of the voltage across the transformer’s primary side and the waveform of the current flowing through the resonant capacitor parallel to the transformer are directly used for the purpose of analyzing the equivalent capacitor. This method is not only a good solution for steady state analysis of DC-DC resonant converter, but also an important examination on the resonant tank. However, it can’t decide the output ripple and the capacitance of the voltage-doubling circuit. This paper not only solves the problem listed above but also decides

**PROPOSED SYSTEM: **

In this paper, a novel voltage-doubling circuit with parallel resonant DC-DC converter is proposed. A novel voltage-doubling circuit can not only reach a higher output voltage but also reduce output ripple to a lower level than the conventional one. Therefore, while having the same voltage multiple levels as conventional ones, the proposed converter can have a smaller output voltage ripple. In addition, the output power can be adjusted by the phase-shift control technique. Using this technique with the parallel resonant tank can make all the switches achieve zero voltage turn on (ZVS). The analytical methodology is proposed and applied to the parallel resonant tank in order to discuss its steady state conditions. By using this method, the output ripple and equivalent capacitance of the voltage-doubling circuit was decided. Finally, a prototype circuit with 400V input voltage, 40kV output voltage and 300 W output power is developed and the performance of the proposed converter is verified.

**CONCLUSIONS **

A novel voltage-doubling circuit with parallel resonant DC-DC converter is proposed in this paper. It can not only reach a higher output voltage but also reduce the output voltage ripple. In this paper, the output voltage ripple is 4.1%, and it’s much lower than the conventional one. Using basic sinusoidal waveform analytical method, it can decide not only the output ripple but also the capacitance of the voltage-doubling circuit. This paper adopted the phase-shift control technique to adjust output power. Then, using this technique with the parallel resonant tank makes all the power switches S a -S d achieve zero voltage switching (ZVS). This technique can be applied to different power conversion systems easily. The design values and experimental results are shown. The whole efficiency of the proposed converter circuit is showed in the, and the highest efficiency is 78.8% at full load. A prototype circuit with input voltage 400V, output voltage 40kV, and output power 300W is developed in the laboratory.

**REFERENCES**

[1] M. Ilic, L. Laskai, J. L. Reynolds, and R. Encallaz, “An isolated high-voltage DC-to-DC converter with fast turn-off capability for X-ray tube gridding,”* IEEE Trans. on Ind. Appl.*, vol. 38, no. 4, pp. 1139-1146, July/August 2002.

[2] J. A. Martin-Ramos, A. M. Pernía, J. Díaz, F. Nuño, and J. A. Martínez, “Power supply for a high-voltage application,” *IEEE Trans. on Power Electron*, vol. 23, no. 4, July 2008.

[3] N. Grass, W. Hartmann, and M. Klockner,J, “Application of different types of high-voltage supplies on industrial electrostatic precipitators,” *IEEE Trans. on Ind. Appl.*, vol. 40, no. 6, pp. 1513-1520, November/December 2004.

[4] I. Barbi, R. Gules, “Isolated DC-DC converters with high-output voltage for TWTA telecommunication satellite applications,” *IEEE Trans. on Power Electron*, vol. 18, no. 4, July 2003.

[5] J. S. Brugler, “Theoretical Performance of Voltage Multiplier Circuits” *IEEE Trans. on Solid * *State Circuit.*, vol. 6, no. 3, pp. 132-135, June. 1971.

[6] L. M. Redondo, “A DC Voltage-Multiplier Circuit Working as a High-Voltage Pulse Generator” *IEEE Trans. on Plasma Science.*, vol. 38, no. 10, pp. 2725-2729, October. 2010.

[7] S. Iqbal, R. Besar, and C. Venkataseshaiah “Single/Three-phase Symmetrical Bipolar Voltage Multipliers for X-ray Power Supply,” *ICEE Trans. Power Electron.*, vol. 19, no. 1, pp. 54– 65, Jan. 2004.

[8] S. Lee, P. Kim, and S. Choi, “High Step-Up Soft-Switched Converters Using Voltage Multiplier Cells” *IEEE Trans. Power Electron.*, vol. 28, no. 7, pp. 3379–3387, July. 2013.

[9] J. Sun, X. Ding, M. Nakaoka and H. Takano, “Series resonant ZCS-PFM DC-DC converter with multistage rectified voltage multiplier and dual-mode PFM control scheme for medical-use high-voltage X-ray power generator”,* IEE Proc.-Power Appl.*, vol. 147, no. 6, pp. 527–534, November. 2000.

[10]P. D. Dharmesh, D. Elangovan, “Soft Switched DC-DC Converter With High Voltage Gain”, *Proceedings of IEEE international conference on *Energy, Automation, and Signal (ICEAS), pp. 1–6, 2011.

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*Abstract*

A novel voltage-doubling circuit with parallel resonant DC-DC converter is proposed. The converter consists of full-bridge inverter, resonant tank, high frequency high voltage transformer, and voltage-doubling circuit. In the high voltage applications, low output voltage ripple has been given much attention. The output voltage step-up ratio is increased by two parts. One is a high frequency high voltage transformer and the other is a voltage-doubling circuit. The novel voltage-doubling circuit can not only reach a higher output voltage but also reduce output ripple to a lower level than the conventional one. Therefore, while maintaining the same output voltage, the transformer’s turn ratio can be reduced compared with the conventional voltage-doubling circuit. The output power can be adjusted by the phase-shift control technique. In addition, combining this technique with the parallel resonant tank can make all the switches achieve zero voltage turn on (ZVS). The operating principles, steady-state analysis, and the parameter designs are discussed in this paper. Finally, a prototype circuit with 400V input voltage, 40kV output voltage, and 300W output power is developed in the laboratory to verify the performance of the proposed converter.

**EXISTING SYSTEM: **

The full-bridge DC-DC converter and phase-shift control technique are widely used in high voltage DC power supply. The adopted conventional full-bridge DC-DC converter usually doesn’t contain resonant tanks. However, the voltage across the transformer’s primary side will ring and cause the consumption of the power converter to increase and the stress of the circuit components to increase. Two basic topologies of resonant circuits are commonly used in the full-bridge DC-DC converter, resonant circuits including the series resonant circuit and parallel resonant circuit. Both of the topologies can make all the switches in the circuit achieve zero voltage switching (ZVS) or zero current switching (ZCS). Therefore, it can reduce the voltage or current stress of the switches and increase the whole efficiency of the converter. Normally, the DC-DC resonant converter can be examined in the time domain or in the frequency domain. It was straightforward for a DC-DC resonant converter to be analyzed by the frequency domain in most of the literature. However, the equivalent circuit in frequency domain was ignored in the equivalent capacitor of the voltage-doubling circuit. The steady state analysis of the RC load was proposed in. In this paper, the waveform of the voltage across the transformer’s primary side and the waveform of the current flowing through the resonant capacitor parallel to the transformer are directly used for the purpose of analyzing the equivalent capacitor. This method is not only a good solution for steady state analysis of DC-DC resonant converter, but also an important examination on the resonant tank. However, it can’t decide the output ripple and the capacitance of the voltage-doubling circuit. This paper not only solves the problem listed above but also decides

**PROPOSED SYSTEM: **

In this paper, a novel voltage-doubling circuit with parallel resonant DC-DC converter is proposed. A novel voltage-doubling circuit can not only reach a higher output voltage but also reduce output ripple to a lower level than the conventional one. Therefore, while having the same voltage multiple levels as conventional ones, the proposed converter can have a smaller output voltage ripple. In addition, the output power can be adjusted by the phase-shift control technique. Using this technique with the parallel resonant tank can make all the switches achieve zero voltage turn on (ZVS). The analytical methodology is proposed and applied to the parallel resonant tank in order to discuss its steady state conditions. By using this method, the output ripple and equivalent capacitance of the voltage-doubling circuit was decided. Finally, a prototype circuit with 400V input voltage, 40kV output voltage and 300 W output power is developed and the performance of the proposed converter is verified.

**CONCLUSIONS **

A novel voltage-doubling circuit with parallel resonant DC-DC converter is proposed in this paper. It can not only reach a higher output voltage but also reduce the output voltage ripple. In this paper, the output voltage ripple is 4.1%, and it’s much lower than the conventional one. Using basic sinusoidal waveform analytical method, it can decide not only the output ripple but also the capacitance of the voltage-doubling circuit. This paper adopted the phase-shift control technique to adjust output power. Then, using this technique with the parallel resonant tank makes all the power switches S a -S d achieve zero voltage switching (ZVS). This technique can be applied to different power conversion systems easily. The design values and experimental results are shown. The whole efficiency of the proposed converter circuit is showed in the, and the highest efficiency is 78.8% at full load. A prototype circuit with input voltage 400V, output voltage 40kV, and output power 300W is developed in the laboratory.

**REFERENCES**

[1] M. Ilic, L. Laskai, J. L. Reynolds, and R. Encallaz, “An isolated high-voltage DC-to-DC converter with fast turn-off capability for X-ray tube gridding,”* IEEE Trans. on Ind. Appl.*, vol. 38, no. 4, pp. 1139-1146, July/August 2002.

[2] J. A. Martin-Ramos, A. M. Pernía, J. Díaz, F. Nuño, and J. A. Martínez, “Power supply for a high-voltage application,” *IEEE Trans. on Power Electron*, vol. 23, no. 4, July 2008.

[3] N. Grass, W. Hartmann, and M. Klockner,J, “Application of different types of high-voltage supplies on industrial electrostatic precipitators,” *IEEE Trans. on Ind. Appl.*, vol. 40, no. 6, pp. 1513-1520, November/December 2004.

[4] I. Barbi, R. Gules, “Isolated DC-DC converters with high-output voltage for TWTA telecommunication satellite applications,” *IEEE Trans. on Power Electron*, vol. 18, no. 4, July 2003.

[5] J. S. Brugler, “Theoretical Performance of Voltage Multiplier Circuits” *IEEE Trans. on Solid * *State Circuit.*, vol. 6, no. 3, pp. 132-135, June. 1971.

[6] L. M. Redondo, “A DC Voltage-Multiplier Circuit Working as a High-Voltage Pulse Generator” *IEEE Trans. on Plasma Science.*, vol. 38, no. 10, pp. 2725-2729, October. 2010.

[7] S. Iqbal, R. Besar, and C. Venkataseshaiah “Single/Three-phase Symmetrical Bipolar Voltage Multipliers for X-ray Power Supply,” *ICEE Trans. Power Electron.*, vol. 19, no. 1, pp. 54– 65, Jan. 2004.

[8] S. Lee, P. Kim, and S. Choi, “High Step-Up Soft-Switched Converters Using Voltage Multiplier Cells” *IEEE Trans. Power Electron.*, vol. 28, no. 7, pp. 3379–3387, July. 2013.

[9] J. Sun, X. Ding, M. Nakaoka and H. Takano, “Series resonant ZCS-PFM DC-DC converter with multistage rectified voltage multiplier and dual-mode PFM control scheme for medical-use high-voltage X-ray power generator”,* IEE Proc.-Power Appl.*, vol. 147, no. 6, pp. 527–534, November. 2000.

[10]P. D. Dharmesh, D. Elangovan, “Soft Switched DC-DC Converter With High Voltage Gain”, *Proceedings of IEEE international conference on *Energy, Automation, and Signal (ICEAS), pp. 1–6, 2011.