Investigation on Dynamic Voltage Restorers With Two DC-Links and Series Converters for Three-Phase Four-Wire Systems

 IEEE, 2014

ABSTRACT

This paper proposes three dynamic voltage restorer (DVR) topologies. Such configurations are able to compensate voltage sags/swells in three-phase four-wire (3P4W) systems under balanced and unbalanced conditions. The proposed systems in this work use two independent dc-links. The complete control system, including the PWM technique, is developed and comparisons between the proposed configurations and a conventional one are performed. Simulation and experimental results are provided to validate the theoretical approach.

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1 Typical DVR location in a 3P4W power distribution system

  EXPECTED SIMULATION RESULTS:

Fig. 2. Simulation results. Injected voltages by the DVR considering conventional 3HB topology and proposed configurations with equal dc-link voltages (vCa=vCb ! dc-link ratio 1:1) and different dc-link voltages (vCa 6= vCb ! dc-link ratios 1:2 and 1:3).

Fig. 3 Simulation results. Dynamic system operation under 30% single-phase sag in time domain. (a) Grid voltages. (b) Injected voltages by DVR. (c) Load voltages.

Fig. 4. Simulation results. Dynamic system operation under 30% two-phase sag in time domain. (a) Grid voltages. (b) Injected voltages by DVR. (c) Load voltages.

Fig. 5. Simulation results. Dynamic system operation under 30% three-phase sag in time domain. (a) Grid voltages. (b) Injected voltages by DVR. (c) Load voltages.

CONCLUSION

In this paper three four-wire dynamic voltage restorers (DVRs) have been presented. The studied configurations in this work are based on the concept of open-end winding. Simulated and experimental results presented show that the proposed DVRs are feasible and suitable for power distribution system with YY transformers with neutrals grounded.

REFERENCES

[1]   W. Brumsickle, G. Luckjiff, R. Schneider, D. Divan, and M. Mc- Granaghan, “Dynamic sag correctors: cost effective industrial power line conditioning,” in Industry Applications Conference, 1999. Thirty-Fourth IAS Annual Meeting. Conference Record of the 1999 IEEE, vol. 2, pp. 1339–1344 vol.2, 1999.

[2]   M. McGranaghan, D. Mueller, and M. Samotyj, “Voltage sags in industrial systems,” Industry Applications, IEEE Transactions on, vol. 29, no. 2, pp. 397–403, 1993.

[3]   C.-m. Ho and H.-H. Chung, “Implementation and performance evaluation of a fast dynamic control scheme for capacitor-supported interline DVR,” Power Electronics, IEEE Transactions on, vol. 25, no. 8,pp. 1975–1988, 2010.

[4]   A. Ghosh and G. Ledwich, “Compensation of distribution system voltage using DVR,” Power Delivery, IEEE Transactions on, vol. 17, no. 4, pp. 1030–1036, 2002.

[5]   J. Nielsen, M. Newman, H. Nielsen, and F. Blaabjerg, “Control and testing of a dynamic voltage restorer (DVR) at medium voltage level,” Power Electronics, IEEE Transactions on, vol. 19, no. 3, pp. 806–813,2004.

Predictive Voltage Control of Transformer-less Dynamic Voltage Restorer

IEEE Transactions on Industrial Electronics, 2013

ABSTRACT:

This paper presents a predictive voltage control scheme for effective control of transformer-less dynamic voltage restorer (TDVR). This control scheme utilizes discrete model of voltage source inverter (VSI) and interfacing filter for generation of switching strategy of inverter switches. Predictive voltage control algorithm based TDVR tracks reference voltage effectively and maintains load voltages sinusoidal during various voltage disturbances as well as load conditions. Moreover, this scheme does not require any linear controller or modulation technique. Simulation and experimental results are presented to verify the performance of proposed scheme.

KEYWORDS:

1.      Predictive voltage control

2.      Transformer-less dynamic voltage restorer (TDVR)

3.      Voltage disturbance

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1. Single-phase TDVR compensated distribution system.

EXPECTED SIMULATION RESULTS:

Fig.2. Simulation waveforms under voltage sag with 5 mH filter inductance. (a) Source voltage. (b) Load voltage.

Fig.3. Simulation waveforms under voltage sag. (a) Source voltage. (b) Load voltage.

Fig.4. Simulation wave forms under voltage swell. (a) Source voltage. (b) Load voltage.

Fig.5. Simulation waveforms under voltage sag with RC type nonlinear load. (a) Source voltage. (b) Load voltage. (c) Load current.

CONCLUSION:

This paper presents the speed control of BLDC motor using anti wind up PI controller and fuzzy controller for three phase BLDC motor. The simulation results are compared with PI controller results. The conventional PI controller results are slower compared to fuzzy and anti wind up controllers. From the simulation results, it is clear that for the load variation anti wind up PI controller gave better response than conventional PI and fuzzy controller. Hence anti wind up PI controller is found to be more suitable for BLDC motor drive during load variation. It can also be observed from the simulation results that performance of fuzzy controller is better during the case of speed variation.

REFERENCES:

[1]   R. Arulmozhiyal, R. Kandibanv, “Design of Fuzzy PID Controller for Brushless DC Motor”, in Proc. IEEE International Conference on Computer Communication and Informatics, Coimbatore, 2012.

[2]   Anirban Ghoshal and Vinod John, “Anti-windup Schemes for Proportional Integral and Proportional Resonant Controller”, in Proc. National Power electronic conference, Roorkee, 2010.

[3]   M. F. Z. Abidin, D. Ishak and A. Hasni Abu Hassan, “A Comparative Study of PI, Fuzzy and Hybrid PI Fuzzy Controller for Speed Control of Brushless DC Motor Drive”, in Proc. IEEE International conference on Computer applications and and Industrial electronics, Malysia, 2011.

[4]   J. Choi, C. W Park, S. Rhyu and H. Sung, “Development and Control of BLDC Motor using Fuzzy Models”,in Proc. IEEE international Conference on Robotics, Automation and Mechatronics, Chengdu, 2004.

[5]   C. Bohn and D.P. Atherton, “An analysis package comparing PID anti-windup strategies,” IEEE Trans. controls system, Vol.15, No. 2, pp.34-40, 1995.

Evaluation of DVR Capability Enhancement -Zero Active Power Tracking Technique

IEEE, 2016

ABSTRACT:

This paper presents a utilization technique for enhancing the capabilities of dynamic voltage restorers (DVRs). This study aims to enhance the abilities of DVRs to maintain acceptable voltages and last longer during compensation. Both the magnitude and phase displacement angle of the synthesized DVR voltage are precisely adjusted to achieve lower power utilization. The real and reactive powers are calculated in real time in the tracking loop to achieve better conditions. This technique results in less energy being taken out of the DC-link capacitor, resulting in smaller size requirements. The results from both the simulation and experimental tests illustrate that the proposed technique clearly achieved superior performance. The DVR’s active action period was considerably longer, with nearly 5 times the energy left in the DC-link capacitor for further compensation compared to the traditional technique. This technical merit demonstrates that DVRs could cover a wider range of voltage sags; the practicality of this idea for better utilization is better than that of existing installed DVRs.

KEYWORDS:

1.      DVR capability

2.      Energy optimized

3.      Energy source

4.      Series compensator

5.      Voltage stability

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig 1: Single-line diagram of a power system with the DVR connected at PCC.

EXPECTED SIMULATION RESULTS:

Fig.2. D-axis voltages at the system (VSd), DVR (VDVRd), and load (VLd). during in-phase compensation (simulation).

Fig. 3. Q-axis voltages at the system (VSq), DVR (VDVRq), and load (VLq) during in-phase compensation (simulation).

Fig. 4. The overall three-phase voltage signals during in-phase compensation (simulation).

Fig.5 Real power at source (PS), the DVR (PDVR) and load (PL) during in- phase compensation (simulation).

Fig. 6 The DVR DC-side voltage (VDC) during in-phase compensation (simulation).

.Fig. 7. D-axis voltages at the system(VSd), DVR (VDVRd), and load (VLd) during zero-real power tracking compensation (simulation).

Fig. 8.. Q-axis voltages at the system (VSq), DVR (VDVRq), and load (VLq) during zero-real power tracking compensation (simulation).

Fig. 9. The overall three-phase voltage signals during zero-real power tracking compensation (simulation).

Fig. 10. Real power at source (PS), the DVR (PDVR) and load (PL) zero-real power tracking compensation (simulation).

CONCLUSION:

It is clear from both the simulation and experimental results illustrated in this paper that the proposed zero-real power tracking technique applied to DVR-based compensation can result in superior performance compared to the traditional in-phase technique. The experimental test results match those proposed using simulation, although some discrepancies due to the imperfect nature of the test circuit components were seen.

With the traditional in-phase technique, the compensation was performed and depended on the real power injected to the system. Then, more of the energy stored in the DC-link capacitor was utilized quickly, reaching its limitation within a shorter period. The compensation was eventually forced to stop before the entire voltage sag period was finished. When the compensation was conducted using the proposed technique, less energy was used for the converter basic switching process.

The clear advantage in terms of the voltage level at the DC-link capacitor indicates that with the proposed technique, more energy remains in the DVR (67% to 14% in the traditional in-phase technique), which guarantees the correct compensating voltage will be provided for longer periods of compensation. With this technique, none (or less) of the real power will be transferred to the system, which provides more for the DVR to cover a wider range of voltage sags, adding more flexible adaptive control to the solution of sag voltage disturbances.

REFERENCES:

[1]   M. Bollen, Understanding Power Quality Problems, Voltage Sags and Interruptions. New York: IEEE Press, 1999.

[2]   J. Roldán-Pérez, A. García-Cerrada, J. L. Zamora-Macho, P. Roncero-Sánchez, and E. Acha, “Troubleshooting a digital repetitive controller for a versatile dynamic voltage restorer,” Int. J. Elect. Power Energy Syst., vol. 57, pp. 105–115, May 2014.

[3]   P. Kanjiya, B. Singh, A. Chandra, and K. Al-Haddad, “SRF theory revisited to control self-supported dynamic voltage restorer (DVR) for unbalanced and nonlinear loads,” IEEE Trans. Ind. Appl., vol. 49, no. 5, pp. 2330–2340, Sep. 2013.

[4]   S. Naidu, and D. Fernandes, “Dynamic voltage restorer based on a four-leg voltage source converter,” IET Generation, Transmission & Distribution, vol. 3, no. 5, pp. 437–447, May 2009.

[5]   T. Jimichi, H. Fujita, and H. Akagi, “A dynamic voltage restorer equipped with a high-frequency isolated dc-dc converter,” IEEE Trans. Ind. Appl., vol. 47, no. 1, pp. 169–175, Jan. 2011.

Dual-Buck AC–AC Converter with Inverting and Non-Inverting Operations

IEEE Transactions on Power Electronics, 2018

ABSTRACT:

A buck-boost ac-ac converter with inverting and non-inverting operations is proposed. It compensates both the voltage sag and swell when used as a dynamic voltage restorer. Its basic switching cell is a unidirectional buck circuit, owing to which it has no shoot-through concerns. It achieves safe commutation without using RC snubbers or soft commutation strategies. Further, it can be implemented with power MOSFETs without their body diodes conducting, and for current freewheeling external diodes of good reverse recovery features can be used to minimize the reverse recovery issues and relevant loss. The detailed theoretical analysis and experimental results of a 300-W prototype converter are provided.

KEYWORDS:

1.      AC–AC converter

2.      Bipolar voltage gain

3.      Commutation

4.      Dual-buck

5.      DVR

6.      MOSFET

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig 1: Proposed buck-boost ac-ac converter

EXPECTED SIMULATION RESULTS:

Fig.2. NIB operation. (a) Input and output voltages and inductor current. (b) Drain-source voltages of switches.

Fig. 3. IBB operation (buck mode). (a) Input and output voltages and inductor current. (b) Drain-source voltages of switches.  

Fig. 4. IBB operation (boost mode). (a) Input and output voltages and inductor current. (b) Drain-source voltages of switches.

Fig.5. INIBB operation (non-inverting buck). (a) Input and output voltages and inductor current. (b) Drain-source voltages of switches.

Fig.6. INIBB operation (inverting buck). (a) Input and output voltages and inductor current. (b) Drain-source voltages of switches.

Fig. 7. INIBB operation (inverting boost). (a) Input and output voltages and inductor current. (b) Drain-source voltages of switches.

Fig. 8. Experimental results with partially inductive load. (a) NIB operation. (b) IBB operation.

Fig. 9. Experimental results with non-linear load in NIB operation.

Fig. 10. Experimental results of the proposed DVR.

CONCLUSION:

In this paper, a novel buck-boost ac-ac converter is proposed. It combined the operations of non-inverting buck and inverting buck-boost converters in one structure. Similar to the buck converter, it has a non-inverting buck operation, and similar to an inverting buck-boost converter, it has an inverting buck-boost operation. In addition, it has an extra operation, in which the output voltage higher or lower than the input voltage that is in-phase or out-of-phase with the input voltage can be obtained. Thus, the proposed converter can compensate both voltage sag and swell when used in a DVR.

The basic unit of the proposed converter is a unidirectional buck circuit, therefore it has no short-circuit and open-circuit problems. It has no commutation problems, and does not require lossy snubbers and/or soft commutation strategies for operation. Further, it can utilize MOSFETs without their body diodes conducting and without reverse recovery issues and relevant losses. A detailed analysis of the proposed converter and DVR has been presented and validated by experimental results.

  

REFERENCES:

[1]   W. E. Brumsickle, R. S. Schneider, G. A. Luckjiff, D. M. Divan, and M. F. McGranaghan, “Dynamic sag correctors: cost-effective industrial power line conditioning,” IEEE Trans. Ind. Appl., vol. 37, no. 1, pp. 212– 217, Jan./Feb. 2001.

[2]   S. Subramanian and M. K. Mishra, “Interphase ac-ac topology for sag supporter,” IEEE Trans. Power Electron., vol. 25, no. 2, pp. 514–518, Feb. 2010.

[3]   IEEE Recommended Practice for Monitoring Electric Power Quality, IEEE Standard 1159-2009 (Revision of IEEE Standard 1159-1995), 2009.

[4]   F. M.-David, S. Bhattacharya and G. Venkataramanan, “A comparative evaluation of series power-flow controllers using dc- and ac-link converters,” IEEE Trans. Power Del., vol. 23, no. 2, pp. 985-996, Apr. 2008.

[5]   D. Francis, and T. Thomas, “Mitigation of voltage sag and swell using dynamic voltage restorer,” 2014 Annual International Conference on Emerging Research Areas: Magnetics, Machines and Drives (AICERA/iCMMD), Kottayam, 2014, pp. 1-6.