Single-Phase AC-DC-AC Multilevel Converter with Transformers Applied to Grid Voltage Compensation

This paper presents a single-phase ac-dc-ac multilevel converter composed of two three-leg converters series-connected throughout two transformers (one on the grid side and one on the load side), sharing the same dc-link, The proposed converter can mitigate grid fundamental overvoltage and can be applied to systems with equal or different voltage levels at the input and output. Besides, the converter allows to feed the load with sinusoidal voltages (with constant amplitude and frequency) and to operate with sinusoidal grid current with high power factor. Circuit model equations, PWM technique based on space vector approaches and a control system are presented. The proposed topology is compared with the conventional one in terms of harmonic distortions and semiconductor power losses. Simulation and experimental results under same conditions are provided for validation purposes.

[1]  Jung-Min Kwon,et al.  High-performance online UPS using three-leg-type converter , 2005, IEEE Trans. Ind. Electron..

[2]  H. van der Broeck,et al.  Analysis and Realization of a Pulse Width Modulator Based on Voltage Space Vectors , 1986, 1986 Annual Meeting Industry Applications Society.

[3]  C.B. Jacobina,et al.  Application of single-phase to three-phase converter motor drive systems with IGBT dual module losses reduction , 2009, 2009 Brazilian Power Electronics Conference.

[4]  Cursino B. Jacobina,et al.  Single-phase ac–dc–ac topology for grid overvoltage and voltage harmonic mitigation , 2017 .

[5]  Cursino B. Jacobina,et al.  Single-phase AC-DC-AC topology for grid voltage compensation , 2017, 2017 IEEE Energy Conversion Congress and Exposition (ECCE).

[6]  Hirofumi Akagi,et al.  The unified power quality conditioner: the integration of series- and shunt-active filters , 1998 .

[7]  Peter W. Lehn,et al.  Control ofAC-DC-ACConverters withMinimized DC Link Capacitanceunder GridDistortion , 2006 .

[8]  Nady Rocha,et al.  Flexible Series/Parallel AC–DC–AC Motor Drive System , 2015, IEEE Transactions on Industry Applications.

[9]  M. Mohamadian,et al.  Parallel operation of series-parallel Uninterruptible Power Supplies , 2016, 2016 7th Power Electronics and Drive Systems Technologies Conference (PEDSTC).

[10]  Madhuri A. Chaudhari,et al.  Power factor improvement using nine switch AC-DC-AC converter , 2016, 2016 IEEE 6th International Conference on Power Systems (ICPS).

[11]  Wang Peng,et al.  An improved control strategy for three-phase AC/DC/AC converter in UPS application , 2016, 2016 Asian Conference on Energy, Power and Transportation Electrification (ACEPT).