A Novel Control Method for Transformerless H-Bridge Cascaded STATCOM with Star Configuration

ABSTRACT

This paper presents a transformerless static synchronous compensator (STATCOM) system based on multilevel H-bridge converter with star configuration. This proposed control methods devote themselves not only to the current loop control but also to the dc capacitor voltage control. With regards to the current loop control, a nonlinear controller based on the passivity-based control (PBC) theory is used in this cascaded structure STATCOM for the first time. As to the dc capacitor voltage control, overall voltage control is realized by adopting a proportional resonant controller. Clustered balancing control is obtained by using an active disturbances rejection controller. Individual balancing control is achieved by shifting the modulation wave vertically which can be easily implemented in a field-programmable gate array. Two actual H-bridge cascaded STATCOMs rated at 10 kV 2 MVA are constructed and a series of verification tests are executed. The experimental results prove that H-bridge cascaded STATCOM with the proposed control methods has excellent dynamic performance and strong robustness. The dc capacitor voltage can be maintained at the given value effectively.

 

KEYWORDS:

Active disturbances rejection controller (ADRC), H-bridge cascaded, passivity-based control (PBC), proportional resonant (PR) controller, shifting modulation wave, static synchronous compensator (STATCOM).

 

SOFTWARE: MATLAB/SIMULINK

 

CONTROL BLOCK DIAGRAM:

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Fig. 1. Control block diagram for the 10 kV 2 MVA H-bridge cascaded STATCOM.

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Fig. 2. Block diagram of PBC.

 

EXPERIMENTAL RESULTS:

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Fig. 3. Experimental results verify the effect of PBC in steady-state process. (a) Ch1: reactive current; Ch2: compensating current; Ch3: residual current of grid. (b) Ch1: reactive current; Ch2: compensating current; Ch3: residual current of grid.

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Fig. 4. Experimental results show the dynamic performance of STATCOM in the dynamic process. Ch1: reactive current; Ch2: compensating current; Ch3: residual current of grid.

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Fig. 5. Experimental results in the startup process and stopping process. (a) Ch1: reactive current; Ch2: compensating current; Ch3: residual current of grid. (b) Ch1: reactive current; Ch2: compensating current; Ch3: residual current of grid.

 

CONCLUSION

This paper has analyzed the fundamentals of STATCOM based on multilevel H-bridge converter with star configuration. And then, the actual H-bridge cascaded STATCOM rated at 10 kV 2 MVA is constructed and the novel control methods are also proposed in detail. The proposed method has the following characteristics.

1) A PBC theory-based nonlinear controller is first used in STATCOM with this cascaded structure for the current loop control, and the viability is verified by the experimental results.

2) The PR controller is designed for overall voltage control and the experimental result proves that it has better performance in terms of response time and damping profile compared with the PI controller.

3) The ADRC is first used in H-bridge cascaded STATCOM for clustered balancing control and the experimental results verify that it can realize excellent dynamic compensation for the outside disturbance.

4) The individual balancing control method which is realized by shifting the modulation wave vertically can be easily implemented in the FPGA.

The experimental results have confirmed that the proposed methods are feasible and effective. In addition, the findings of this study can be extended to the control of any multilevel voltage source converter, especially those with H-bridge cascaded structure.

 

REFERENCES

[1] B. Gultekin and M. Ermis, “Cascaded multilevel converter-based transmission STATCOM: System design methodology and development of a 12 kV ±12 MVAr power stage,” IEEE Trans. Power Electron., vol. 28, no. 11, pp. 4930–4950, Nov. 2013.

[2] B. Gultekin, C. O. Gerc¸ek, T. Atalik, M. Deniz, N. Bic¸er, M. Ermis, K. Kose, C. Ermis, E. Koc¸, I. C¸ adirci, A. Ac¸ik, Y. Akkaya, H. Toygar, and S. Bideci, “Design and implementation of a 154-kV±50-Mvar transmission STATCOM based on 21-level cascaded multilevel converter,” IEEE Trans. Ind. Appl., vol. 48, no. 3, pp. 1030–1045, May/Jun. 2012.

[3] S. Kouro, M. Malinowski, K. Gopakumar, L. G. Franquelo, J. Pou, J. Rodriguez, B.Wu,M. A. Perez, and J. I. Leon, “Recent advances and industrial applications of multilevel converters,” IEEE Trans. Ind. Electron., vol. 57, no. 8, pp. 2553–2580, Aug. 2010.

[4] F. Z. Peng, J.-S. Lai, J. W. McKeever, and J. VanCoevering, “A multilevel voltage-source inverter with separateDCsources for static var generation,” IEEE Trans. Ind. Appl., vol. 32, no. 5, pp. 1130–1138, Sep./Oct. 1996.

[5] Y. S. Lai and F. S. Shyu, “Topology for hybrid multilevel inverter,” Proc. Inst. Elect. Eng.—Elect. Power Appl., vol. 149, no. 6, pp. 449–458, Nov. 2002.

A Novel High StepUp DC DC Converter Based on Integrating Coupled Inductor and Switched-Capacitor Techniques for Renewable Energy Applications

ABSTRACT

In this paper, a novel high development up dc/dc converter is shown for maintainable power source applications. The proposed structure involves a coupled inductor and two voltage multiplier cells, in order to get high development up voltage gain. Likewise, two capacitors are charged in the midst of the kill time frame, using the essentialness set away in the coupled inductor which manufactures the voltage trade gain. The essentialness set away in the spillage inductance is reused with the use of a dormant fasten circuit. The voltage load on the basic power switch is furthermore diminished in the proposed topology. Thusly, a key influence switch with low resistance RDS(ON) can be used to diminish the conduction incidents. The action rule and the tireless state examinations are discussed inside and out. To check the execution of the showed converter, a 300-W lab demonstrate circuit is completed. The results affirm the speculative examinations and the practicability of the showed high development up converter.

 CIRCUIT DIAGRAM:

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Fig. 1. Circuit configuration of the presented high-step-up converter.

SIMULATION RESULTS:

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Fig. 2. Simulation results under load 300 W.

 CONCLUSION

This paper demonstrates another high-advance up dc/dc converter for maintainable power source applications. The suggested converter is fitting for DG systems reliant on practical power sources, which require high-advance up voltage trade gain. The essentialness set away in the spillage inductance is reused to upgrade the execution of the showed converter. In addition, voltage load on the essential power switch is diminished. In like manner, a switch with a low on-state obstacle can be picked. The continuing state errand of the converter has been dismembered in detail. Moreover, the limit condition has been procured. Finally, a hardware show is executed which changes over the 40-V input voltage into 400-V yield voltage. The results exhibit the credibility of the presented converter.