Comprehensive Study of Single-Phase AC-DC Power Factor Corrected Converters with High-Frequency Isolation

ABSTRACT: Solid-state switch mode AC-DC converters having high-frequency transformer isolation are developed in buck, boost, and buck-boost configurations with improved power quality in terms of reduced total harmonic distortion (THD) of input current, power-factor correction (PFC) at AC mains and precisely regulated and isolated DC output voltage feeding to loads from few Watts to several kW. This paper presents a comprehensive study on state of art of power factor corrected single-phase AC-DC converters configurations, control strategies, selection of components and design considerations, performance evaluation, power quality considerations, selection criteria and potential applications, latest trends, and future developments. Simulation results as well as comparative performance are presented and discussed for most of the proposed topologies.

 

INDEX TERMS: AC-DC converters, harmonic reduction, high-frequency (HF) transformer isolation, improved power quality converters, power-factor correction.

 

SOFTWARE: MATLAB/SIMULINK

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Fig. 1. Classification of improved power quality single-phase AC-DC converters with HF transformer isolation.

CIRCUIT CONFIGURATIONS

A. Buck AC-DC Converters

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Fig. 2. Buck forward AC-DC converter with voltage follower control.

Fig. 3. Buck push-pull AC-DC converter with voltage follower control.

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Fig. 4. Half-bridge buck AC-DC converter with voltage follower control.

Fig. 5. Buck full-bridge AC-DC converter with voltage follower control

 B. Boost AC-DC Converters

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Fig. 6. Boost forward AC-DC converter with current multiplier control.

Fig. 7. Boost push-pull AC-DC converter with current multiplier control.

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Fig. 8. Boost half-bridge AC-DC converter with current multiplier control.

Fig. 9. Boost full-bridge AC-DC converter with current multiplier control.

 C. Buck-Boost AC-DC Converters

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Fig. 10. Flyback AC-DC converter with current multiplier control.

Fig. 11. Cuk AC-DC converter with voltage follower control.

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Fig. 12. SEPIC AC-DC converter with voltage follower control.

Fig. 13. Zeta AC-DC converter with voltage follower control.

 

SIMULATION RESULTS:

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Fig. 14. Current waveforms and its THD for buck AC-DC converter topologies in CCM. (a) Forward buck topology (Fig. 2).( b) Push-pull buck topology (Fig. 3). (c) Half-bridge buck topology (Fig. 4). (d) Bridge buck topology (Fig. 5).

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Fig. 15. Current waveforms and its THD for boost AC-DC converter topologies in CCM. (a) Forward boost topology (Fig. 6). (b) Push-pull boost topology (Fig. 7). (c) Half-bridge boost topology (Fig. 8). (d) Bridge boost topology (Fig. 9).

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Fig. 16. Current waveforms and its THD for buck-boost AC-DC converter topologies in CCM. (a) Flyback topology (Fig. 10). (b) Cuk topology (Fig. 11). (c) SEPIC topology (Fig. 12). (d) Zeta topology (Fig. 13).

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Fig. 17. Current waveforms and its THD for buck AC-DC converter topologies in DCM. (a) Forward buck topology (Fig. 2). (b) Push-pull buck topology (Fig. 3). (c) Half-bridge buck topology (Fig. 4). (d) Bridge buck topology (Fig. 5).

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Fig. 18. Current waveforms and its THD for boost AC-DC converter topologies in DCM. (a) Forward boost topology (Fig. 6). (b) Push-pull boost topology (Fig. 7).

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Fig. 19. Current waveforms and its THD for buck-boost AC-DC converter topologies in DCM. (a) Flyback topology (Fig. 10). (b) Cuk topology (Fig. 11). (c) SEPIC topology (Fig. 12). (d) Zeta topology (Fig. 13).

 

CONCLUSION

A comprehensive review of the improved power quality HF transformer isolated AC-DC converters has been made to present a detailed exposure on their various topologies and its design to the application engineers, manufacturers, users and researchers. A detailed classification of these AC-DC converters into 12 categories with number of circuits and concepts has been carried out to provide easy selection of proper topology for a specific application. These AC-DC converters provide a high level of power quality at AC mains and well regulated, ripple free isolated DC outputs. Moreover, these converters have been found to operate very satisfactorily with very wide AC mains voltage and frequency variations resulting in a concept of universal input. The new developments in device technology, integrated magnetic and microelectronics are expected to provide a tremendous boost for these AC-DC converters in exploring number of additional applications. It is hoped that this exhaustive design and simulation of these HF transformer isolated AC-DC converters is expected to be a timely reference to manufacturers, designers, researchers, and application engineers working in the area of power supplies.

 

REFERENCES

[1] IEEE Recommended Practices and Requirements for Harmonics Control in Electric Power Systems, IEEE Standard 519, 1992.

[2] Electromagnetic Compatibility (EMC) – Part 3: Limits- Section 2: Limits for Harmonic Current Emissions (equipment input current 􀀀16 A per phase), IEC1000-3-2 Document, 1st ed., 1995.

[3] A. I. Pressman, Switching Power Supply Design, 2nd ed. New York: McGraw-Hill, 1998.

[4] K. Billings, Switchmode Power Supply Handbook, 2nd ed. NewYork: McGraw-Hill, 1999.

[5] N. Mohan, T. Udeland, and W. Robbins, Power Electronics: Converters, Applications and Design, 3rd ed. New York: Wiley, 2002.

New AC-DC Power Factor Correction Architecture Suitable for High Frequency Operation

 

ABSTRACT:

 This paper presents a novel ac-dc power factor correction (PFC) power conversion architecture for single-phase grid interface. The proposed architecture has significant advantages for achieving high efficiency, good power factor, and converter miniaturization, especially in low-to-medium power applications. The architecture enables twice-line-frequency energy to be buffered at high voltage with a large voltage swing, enabling reduction in the energy buffer capacitor size, and elimination of electrolytic capacitors. While this architecture can be beneficial with a variety of converter topologies, it is especially suited for system miniaturization by enabling designs that operate at high frequency (HF, 3 – 30 MHz). Moreover, we introduce circuit implementations that provide efficient operation in this range. The proposed approach is demonstrated for an LED driver converter operating at a (variable) HF switching frequency (3 – 10 MHz) from 120Vac, and supplying a 35Vdc output at up to 30W. The prototype converter achieves high efficiency (92 %) and power factor (0.89), and maintains good performance over a wide load range. Owing to architecture and HF operation, the prototype achieves a high ‘box’ power density of 50W/ in3 (‘displacement’ power density of 130W/ in3), with miniaturized inductors, ceramic energy buffer capacitors, and a small-volume EMI filter.

KEYWORDS:

  1. AC-DC
  2. High frequency
  3. Buck
  4. Power factor correction PFC
  5. Power factor
  6. LED
  7. Electromagnetic interference EMI

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

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Fig. 1: The proposed grid interface power conversion architecture comprises a line-frequency rectifier, a stack of capacitors, a set of regulating converters, and a power combining converter.

EXPECTED SIMULATION RESULTS:

 image004Fig. 2: Operation of the prototype converter from a 120Vac line voltage to a 35Vdc output. Each figure illustrates voltage and / or current waveforms over the ac line cycle: (a) the measured 120Vac line input voltage and the measured voltages across the capacitor stack (output of the bridge rectifier) (b) the measured voltages across C1 and across C2 for a delivered output power of 29W (c) the measured input current waveform at 29W output power (d) the measured input current waveform at 20W output power (e) the output voltage waveform at 29W output power (f) the switched capacitor voltage waveform at 29W output power.

CONCLUSION:

A new single-phase grid interface ac-dc PFC architecture is introduced and experimentally demonstrated. In addition to enabling high efficiency and good power factor, this PFC architecture is particularly advantageous in that it enables extremely high operating frequencies (into the HF range) and reduction in energy buffer capacitor values, each of which contributes to converter miniaturization. The proposed stacked combined architecture significantly decreases the voltage stress of the active and passive devices and reduces characteristic impedance levels, enabling substantial increases in switching frequency when utilized with appropriate converter topologies. Moreover, good power factor is achieved while dynamically buffering twice-line-frequency ac energy with relatively small capacitors operating with large voltage swing. The prototype converter achieves high efficiency and good power factor over a wide power range, and meets the CISPR Class-B Conducted electromagnetic interference (EMI) Limits. The prototype converter based on the architecture and selected high-frequency circuit topology demonstrates an approximate factor of 10 reduction in volume compared to typical designs. The prototype has a very high ‘box’ power density of 50W=in3 (‘displacement’ power density of 130W=in3) with miniaturized inductors, a small volume of EMI filter, and ceramic energy buffer capacitors. Lastly, as described in the appendix, the proposed architecture can be realized in various ways (e.g., with alternative topologies) to realize features such as galvanic isolation and universal input range.

REFERENCES:

[1] O. Garcia, J. Cobos, R. Prieto, P. Alou, and J. Uceda, “Single phase power factor correction: a survey,” Power Electronics, IEEE Transactions on, vol. 18, no. 3, pp. 749–755, May 2003.

[2] G. Moschopoulos and P. Jain, “Single-phase single-stage power-factor corrected converter topologies,” Industrial Electronics, IEEE Transactions on, vol. 52, no. 1, pp. 23–35, Feb 2005.

[3] B. Singh, B. Singh, A. Chandra, K. Al-Haddad, A. Pandey, and D. Kothari, “A review of single-phase improved power quality ac-dc converters,” Industrial Electronics, IEEE Transactions on, vol. 50, no. 5, pp. 962–981, Oct 2003.

[4] Energy Star, “Energy star program requirements for integral LED lamps,” Energy Star, Tech. Rep., Aug. 2010.

[5] ——, “Energy star program requirements for computers,” Energy Star, Tech. Rep., Jun. 2014.

[6] D. Perreault, J. Hu, J. Rivas, Y. Han, O. Leitermann, R. Pilawa- Podgurski, A. Sagneri, and C. Sullivan, “Opportunities and challenges in very high frequency power conversion,” in Applied Power Electronics Conference and Exposition, 2009. APEC 2009. Twenty-Fourth Annual IEEE, Feb 2009, pp. 1–14.