A Unity Power Factor Bridgeless Isolated-Cuk Converter Fed Brushless-DC Motor Driv

       

ABSTRACT:

This work presents a power factor correction (PFC) based bridgeless isolated Cuk converter fed brushless DC (BLDC) motor drive. A variable DC link voltage of the voltage source inverter (VSI) feeding BLDC motor is used for its speed control. This allows the operation of VSI in fundamental frequency switching (FFS) to achieve an electronic commutation of BLDC motor for reduced switching losses. A bridgeless configuration of an isolated Cuk converter is derived for elimination of front end diode bridge rectifier (DBR) to reduce conduction losses in it. The proposed PFC based bridgeless isolated-Cuk converter is designed to operate in discontinuous inductor current mode (DICM) to achieve an inherent PFC at AC mains. The proposed drive is controlled using a single voltage sensor to develop a cost effective solution. The proposed drive is implemented to achieve a unity power factor at AC mains for a wide range of speed control and supply voltages. An improved power quality is achieved at AC mains with power quality indices within limits of IEC 61000-3-2 standard.

KEYWORDS:

1.      BLDC Motor

2.      Bridgeless Isolated Cuk Converter

3.      Discontinuous Inductor Current Mode

4.      Power Factor Correction

5.      Power Quality

6.      Voltage Source Inverter

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. Proposed configuration of a bridgeless isolated Cuk converter feeding BLDC motor drive.

 EXPECTED SIMULATION RESULTS:

Fig. 2. Test results of the proposed drive during its operation at rated loading condition with DC link voltage as (a) 130 V and (b) 50 V.

Fig. 3. Test results of the proposed drive during its operation at rated condition showing (a) input inductor currents (b) output inductors current and (c) HFT currents.

Fig. 4. Test results of the proposed drive during its operation at rated condition showing intermediate capacitors voltages (a) VC11 and VC12 and (b) VC21 and VC22.

Fig. 5. (a) Test results of the proposed drive during its operation at rated condition showing (a) voltage and current stress on PFC converter switches and (b) its enlarged waveforms.

Fig. 6. Test results of the proposed drive during (a) starting at DC link voltage of 50V, (b) speed control corresponding to change in DC link voltage fro 50V to 100V and (c) supply voltage fluctuation from 250V to 200V.

CONCLUSION:

A new configuration of bridgeless isolated-Cuk converter fed BLDC motor drive has been proposed for low power household appliances. The speed control of BLDC motor has been achieved by controlling the DC link voltage of VSI feeding BLDC motor. This has facilitated the operation of VSI in low frequency switching mode for reducing the switching losses associated with it. This bridgeless isolated-Cuk converter has been designed for the elimination of diode bridge rectifier at the front-end for reducing the conduction losses in the front-end converter. This PFC converter has been operated in DICM for DC link voltage control and inherent power factor correction is achieved at the AC mains. A prototype of proposed drive has been implemented using a DSP. Satisfactory test results for proposed bridgeless isolated- Cuk-converter fed BLDC motor has been evaluated for its operation over complete speed range. Moreover, the performance of proposed drive is also evaluated for operation at wide range of supply voltages. The obtained power quality indices have been found within the limits of power quality standards such as IEC 61000-3-2.

REFERENCES:

[1] C. L. Xia, Permanent Magnet Brushless DC Motor Drives and Controls Wiley Press, Beijing, 2012.

[2] Y. Chen, C. Chiu, Y. Jhang, Z. Tang and R. Liang, “A Driver for the Single-Phase Brushless DC Fan Motor with Hybrid Winding Structure,” IEEE Trans. Ind. Electron., vol. 60, no. 10, pp. 4369

[3] X. Huang, A. Goodman, C. Gerada, Y. Fang and Q. L Matrix Converter Drive for a Brushless DC Motor in Aerospace Applications,” IEEE Trans. Ind. Elect., Sept. 2012.

[4] J. Moreno, M. E. Ortuzar and J. W. Dixon, “Energy for a hybrid electric vehicle, using ultra capacitors and neural networks,” IEEE Trans. Ind. Electron., vol.53, no.2, pp. 614

[5] P. Pillay and R. Krishnan, “Modeling of permanent magnet motor drives,” IEEE Trans. Ind. Elect.vol.35, no.4, pp. 537-541, Nov 1988.

A BL-CSC Converter Fed BLDC Motor Drive with Power Factor Correction

ABSTRACT:

This paper presents a power factor correction (PFC) based bridgeless-canonical switching cell (BL-CSC) converter fed brushless DC (BLDC) motor drive. The proposed BL-CSC converter operating in a discontinuous inductor current mode is used to achieve a unity power factor at the AC mains using a single voltage sensor. The speed of BLDC motor is controlled by varying the DC bus voltage of the voltage source inverter (VSI) feeding BLDC motor via a PFC converter. Therefore, the BLDC motor is electronically commutated such that the VSI operates in fundamental frequency switching for reduced switching losses. Moreover, the bridgeless configuration of CSC converter offers low conduction losses due to partial elimination of diode bridge rectifier at the front end. The proposed configuration shows a considerable increase in efficiency as compared to the conventional scheme. The performance of the proposed drive is validated through experimental results obtained on a developed prototype. Improved power quality is achieved at the AC mains for a wide range of control speeds and supply voltages. The obtained power quality indices are within the acceptable limits of IEC 61000-3-2.

KEYWORDS:

1.      BLDC Motor

2.      BL-CSC Converter

3.      DICM

4.      PFC

5.      Power Quality

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. Proposed BL-CSC converter fed BLDC motor drive

EXPECTED SIMULATION RESULTS:

Fig. 2. Performance of the proposed drive at rated condition with supply voltage as 220V and DC link voltage as (a) 310V and (b) 70V.

Fig. 3. Waveforms of (a) inductor’s currents and (b) intermediate capacitor voltage with supply voltage at rated load on BLDC motor with DC link voltage as 310V and supply voltage as 220V.

Fig. 4. Stress on PFC converter switches and its enlarged waveforms during its operation at rated conditions.

Fig. 5. Recorded dynamic performance of the proposed drive at rated load on BLDC motor during (a) starting at Vdc=50V, (b) speed control during change in DC link voltage from 100V to 170V and (c) sudden change in supply voltage from 250V to 180V.

CONCLUSION:

A PFC based BL-CSC converter fed BLDC motor drive has been proposed with improved power quality at the AC mains. A bridgeless configuration of a CSC converter has been used for achieving reduced conduction losses in PFC converter. The speed control of BLDC motor and power factor correction at AC mains has been achieved using a single voltage sensor. The switching losses in the VSI have been reduced by the use of fundamental frequency switching by electronically commutating the BLDC motor. Moreover, the speed of BLDC motor has been controlled by controlling the DC link voltage of the VSI. The proposed drive has shown an improved power quality at the AC mains for a wide range of speed control and supply voltages. The obtained power quality indices have been found within the acceptable limits of IEC 61000-3-2. A satisfactory performance of the proposed drive has been obtained and it is a recommended solution for low power applications.

REFERENCES:

[1] B. Singh and S. Singh, “Single-phase power factor controller topologies for permanent magnet brushless DC motor drives,” IET Power Elect., vol.3, no.2, pp.147-175, March 2010.

[2] Chang Liang Xia, Permanent Magnet Brushless DC Motor Drives and Controls, Wiley Press, Beijing, 2012.

[3] P. Pillay and R. Krishnan, “Modeling of permanent magnet motor drives,” IEEE Trans. Ind. Elect., vol.35, no.4, pp.537-541, Nov 1988.

[4] M. A. Rahman and P. Zhou, “Analysis of brushless permanent magnet synchronous motors,” IEEE Trans. Ind. Elect., vol.43, no.2, pp.256-267, Apr 1996.

[5] J. Moreno, M. E. Ortuzar and J.W. Dixon, “Energy-management system for a hybrid electric vehicle, using ultra capacitors and neural networks,” IEEE Trans. Ind. Elect., vol.53, no.2, pp. 614- 623, April 2006.

Performance comparison of PI & ANN based STATCOM for 132 KV transmission line

ABSTRACT:

This paper presents simulation model of the 132KV transmission line with comparison of ANN based STATCOM and conventional PI based STATCOM. The STATCOM being the state-of-the-art VSC based dynamic shunt compensator in FACTS family is used now a days in transmission system for reactive power control, increase of power transfer capacity, voltage regulation etc. Such type of controller is applied at the middle of the transmission line to enhance the power transmission capacity of the line. The simulation result shows that the STATCOM is effective improve the power factor and voltage regulation for the 132kV line loading.

KEYWORDS:

1.      STATCOM

2.       PI

3.      ANN control strategy

4.      MatLab simulink

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig 1: Schematic Representation of the Control Circuit.

EXPECTED SIMULATION RESULTS:

Fig 2 1-phase current and voltage waveform using STATCOM

Fig3 Phase Current and Voltage waveform when the STATCOM is ON

Fig 4Phase Current and Voltage waveform when Load is Varied in the system

Fig 5 Phase Current and Voltage waveform when suddenly a Load is remove from the system at 0.4sec

Fig 6 3-phase current and voltage waveform using STATCOM

Fig 7 Active and Reactive power flow in Transmission system using STATCOM

Fig8 1-phase current and voltage waveform for STATCOM using ANN

Fig 9 Phase Current and Voltage waveform when the STATCOM is ON

Fig 10 1 Phase Current and Voltage waveform when Load is Varied in the System

Fig11 3-phase voltage and current waveform for STATCOM using ANN

CONCLUSION:

The paper present that the STATCOM bring the power factor to the unity thereby enhancing the power transfer capability by supplying or absorbing controllable amount of reactive power. By using a STATCOM with ANN controller and the Response time is faster comparing to the PI Controller because of this voltage regulation maintained within a limit. More over ANN Controlled STATCOM will improve the stability of the system and improve the dynamic performance of the system.

REFERENCES:

[1] B.Sing ,R.saha, A.Chandra “Static Synchronous Compensator (STATCOM): a review” IET Power Electronic 2008

[2] N.G Hingroni and I Gyugyi. “Understanding FACTS: Concepts and Technology of flexible AC Transmission System”, IEEE Press, New York, 2000.

[3] D.J Hanson, M.L.Woodhouse, C.Horwill “STATCOM: a new era of Reactive Compensation” Power Engineering Journal June 2002

[4] Mustapha Benghanem — Azeddine Draou” A NEW MODELLING AND CONTROL ANALYSIS OF AN ADVANCED STATIC VAR COMPENSATOR USING A THREE–LEVEL (NPC) INVERTER TOPOLOGY” Journal of ELECTRICAL ENGINEERING, VOL. 57, NO. 5, 2006, 285–290

[5] Jagdish Kumar, Biswarup Das, and Pramod Agarwal “ Modeling of 11- Level Cascade Multilevel STATCOM” International Journal of Recent Trends in Engineering, Vol 2, No. 5, November 2009

An Interline Dynamic Voltage Restoring and Displacement Factor Controlling Device (IVDFC)

 ABSTRACT:

An interline dynamic voltage restorer (IDVR) is invariably employed in distribution systems to mitigate voltage sag/swell problems. An IDVR merely consists of several dynamic voltage restorers (DVRs) sharing a common dc link connecting independent feeders to secure electric power to critical loads. While one of the DVRs compensates for the local voltage sag in its feeder, the other DVRs replenish the common dc-link voltage. For normal voltage levels, the DVRs should be bypassed. Instead of bypassing the DVRs in normal conditions, this paper proposes operating the DVRs, if needed, to improve the displacement factor (DF) of one of the involved feeders. DF improvement can be achieved via active and reactive power exchange (PQ sharing) between different feeders. To successfully apply this concept, several constraints are addressed throughout the paper. Simulation and experimental results elucidate and substantiate the proposed concept.

KEYWORDS:

1.      Displacement factor improvement

2.      Interline dynamic voltage restorer (IDVR)

3.      Interline dynamic voltage restoring and displacement factor controlling (IVDFC)

4.      PQ sharing mode

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 Fig. 1. Single line diagram of an IPFC in transmission system.

EXPECTED SIMULATION RESULTS:

Fig. 2. Per-phase PQ sharing mode simulation results: (a)–(c) for first case and (d)–(f) for the second case.

Fig. 3. Per-phase simulation results for voltage sag condition at: (a) feeder 1 and (b) feeder 2.

Fig. 4. Per-phase experimental and corresponding simulation results for DF improvement case: (a) and (b) receiving feeder; (c) and (d) sourcing feeder (time/div= 10 ms/div).

Fig. 5 Per-phase experimental results and corresponding simulation results for voltage sag case: (a) and (b) at feeder 1 and (c) and (d) at feeder 2 (time/div = 10 ms/div).

Fig. 6 Per-phase experimental results and corresponding simulation results for voltage swell case at: (a) and (b) feeder 1 and (c) and (d) at feeder 2 (time/div = 10 ms/div).

CONCLUSION

This paper proposes a new operational mode for the IDVR to improve the DF of different feeders under normal operation. In this mode, theDFof one of the feeders is improved via active and reactive power exchange (PQ sharing) between feeders through the common dc link.

The same system can also be used under abnormal conditions for voltage sag/swell mitigation. The main conclusions of this work can be summarized as follows:

1) Under PQ sharing mode, the injected voltage in any feeder does not affect its load voltage/current magnitude, however, it affects the DFs of both sourcing and receiving feeders. The DF of the sourcing feeder increases while the DF of the receiving feeder decreases.

2) When applying the proposed concept, some constraints should be satisfied to maintain the DF of both sourcing and receiving feeders within acceptable limits imposed by the utility companies. These operational constraints have been identified and considered.

3) The proposed mode is highly beneficial if the active power rating of the receiving feeder is higher than the sourcing feeder. In this case, the DF of the sourcing feeder will have a notable improvement with only a slight variation in DF of the receiving feeder.

The proposed concept has been supported with simulation and experimental results.

REFERENCES:

[1] S. A. Qureshi and N. Aslam, “Efficient power factor improvement technique and energy conservation of power system,” Int. Conf. Energy Manage. Power Del., vol. 2, pp. 749–752, Nov. 21–23, 1995.

[2] J. J. Grainger and S. H. Lee, “Optimum size and location of shunt capacitors for reduction of losses on distribution feeders,” IEEE Trans. Power App. Syst., vol. PAS-100, no. 3, pp. 1105–1118, Mar. 1981.

[3] S. M. Kannan, P. Renuga, and A. R. Grace, “Application of fuzzy logic and particle swarm optimization for reactive power compensation of radial distribution systems,” J. Electr. Syst., 6-3, vol. 6, no. 3, pp. 407–425, 2010.

[4] L. Ramesh, S. P. Chowdhury, S. Chowdhury, A. A. Natarajan, and C. T. Gaunt, “Minimization of power loss in distribution networks by different techniques,” Int. J. Electr. Power Energy Syst. Eng., vol. 3, no. 9, pp. 521–527, 2009.

[5] T. P.Wagner, A. Y. Chikhani, and R. Hackam, “Feeder reconfiguration for loss reduction: An application of distribution automation,” IEEE Trans. Power Del., vol. 6, no. 4, pp. 1922–1933, Oct. 1991.

Three-Level 48-Pulse STATCOM with Pulse Width Modulation

 ABSTRACT:

In this paper, a new control strategy of a three level 48-pulse static synchronous compensator (STATCOM) is proposed with a constant dc link voltage and pulse width modulation at fundamental frequency switching. The proposed STATCOM is realized using eight units of three-level voltage source converters (VSCs) to form a three-level 48-pulse STATCOM. The conduction angle of each three-level VSC is modulated to control the ac converter output voltage, which controls the reactive power of the STATCOM. A fuzzy logic controller is used to control the STATCOM. The dynamic performance of the STATCOM is studied for the control of the reference reactive power, the reference terminal voltage and under the switching of inductive and capacitive loads.

KEYWORDS:

1.      Fuzzy logic control (FLC)

2.      Static synchronous compensator (STATCOM)

3.      Voltage source converter (VSC)

4.      Flexible ac transmission system (FACTS)

5.      Power frequency switching (PFS)

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig. 1 System configuration for simulation

 EXPECTED SIMULATION RESULTS:

Fig. 2 a Dynamic performance of STATCOM for varying the reference reactive power. b Zoomed-in waveforms of the STATCOM ac current as well the dc current during a floating, b capacitive and c inductive operations

Fig. 3 Dynamic performance of STATCOM for varying the reference terminal voltage

Fig. 4 Dynamic performance of STATCOM by switching on inductive and capacitive loads

Fig. 5 a ac terminal voltage without STATCOM on switching non-linear load. b Dynamic performance of STATCOM and ac terminal voltage by switching on switching non-linear load

Fig. 6 Dynamic performance of STATCOM by switching on large value of apparent power

Fig. 7 Dynamic performance of STATCOM under short circuit of the upper half of the dc bus capacitance

Fig. 8 Dynamic performance of STATCOM under short circuit of the complete dc bus capacitance

Fig. 9 a Variation of the dc voltage with sudden load change using a PI and an FLC. b Variation of the ac terminal voltage with sudden load change using a PI and an FLC

CONCLUSION:

A new control strategy of a three-level 48-pulse STATCOM has been proposed with a constant dc link voltage and pulse width modulation at fundamental frequency switching. Its performance has been validated using MATLAB/Simulink. Simulation results have validated the satisfactory dynamic and steady performances of the proposed STATCOM operation. The harmonic content of the STATCOM current is found well below 5 % as per IEEE 519 standard [27].

REFERENCES:

1. T. Johns, A. Ter-Gazarian, D.F. Warne, Flexible ac transmission systems (FACTS), IEE Power Energy Series, the Institute of Electrical Engineers, London, UK, 1999

2. N.G. Hingorani, L. Gyugyi, Understanding FACTS: Concepts and Technology of Flexible ac Transmission Systems (IEEE Press, 2000)

3. R.M. Mathur, R.K. Verma, Thyristor-Based FACTS Controllers for Electrical Transmission Systems (Wiley-IEEE Press, 2002)

4. K.R. Padiyar, FACTS Controllers in Power Transmission and Distribution (New Age International (P) Limited Publishers, India, 2007)

5. K.K. Sen, Introduction to FACTS Controllers: Theory, Modeling and Applications (Wiley-IEEE Press, 2009)