An Adjustable-Speed PFC Bridgeless Buck Boost Converter-Fed BLDC Motor Drive

ABSTRACT

This paper presents a power factor corrected (PFC) bridgeless (BL) buck–boost converter-fed brushless direct current (BLDC) motor drive as a cost-effective solution for low-power applications. An approach of speed control of the BLDC motor by controlling the dc link voltage of the voltage source inverter (VSI) is used with a single voltage sensor. This facilitates the operation of VSI at fundamental frequency switching by using the electronic commutation of the BLDC motor which offers reduced switching losses. A BL configuration of the buck–boost converter is proposed which offers the elimination of the diode bridge rectifier, thus reducing the conduction losses associated with it. A PFC BL buck–boost converter is designed to operate in discontinuous inductor current mode (DICM) to provide an inherent PFC at ac mains. The performance of the proposed drive is evaluated over a wide range of speed control and varying supply voltages (universal ac mains at 90–265 V) with improved power quality at ac mains. The obtained power quality indices are within the acceptable limits of international power quality standards such as the IEC 61000-3-2. The performance of the proposed drive is simulated in MATLAB/Simulink environment, and the obtained results are validated experimentally on a developed prototype of the drive.

KEYWORDS:

1.      Bridgeless (BL) buck–boost converter

2.      Brushless direct current (BLDC) motor

3.      Discontinuous inductor current mode (DICM)

4.      Power factor corrected (PFC)

5.      Power quality.

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. Proposed BLDC motor drive with front-end BL buck–boost converter.

EXPECTED SIMULATION RESULTS:

Fig. 2. Steady-state performance of the proposed BLDC motor drive at rated conditions.

Fig. 3. Harmonic spectra of supply current at rated supply voltage and rated loading on BLDC motor for a dc link voltage of (a) 200 V and (b) 50V.

Fig. 4. Dynamic performance of proposed BLDC motor drive during (a) starting, (b) speed control, and (c) supply voltage variation at rated conditions.

Fig. 5. Harmonic spectra of supply current at rated loading on BLDC motor with dc link voltage as 200 V and supply voltage as (a) 90 V and (b) 270 V.

Fig. 6. Steady-state performance of the proposed BLDC motor drive at rated conditions with dc link voltage as (a) 200 V and (b) 50 V.

CONCLUSION

A PFC BL buck–boost converter-based VSI-fed BLDC motor drive has been proposed targeting low-power applications. A new method of speed control has been utilized by controlling the voltage at dc bus and operating the VSI at fundamental frequency for the electronic commutation of the BLDC motor for reducing the switching losses in VSI. The front-end BL buck–boost converter has been operated in DICM for achieving an inherent power factor correction at ac mains. A satisfactory performance has been achieved for speed control and supply voltage variation with power quality indices within the acceptable limits of IEC 61000-3-2. Moreover, voltage and current stresses on the PFC switch have been evaluated for determining the practical application of the proposed scheme. Finally, an experimental prototype of the proposed drive has been developed to validate the performance of the proposed BLDC motor drive

under speed control with improved power quality at ac mains. The proposed scheme has shown satisfactory performance, and it is a recommended solution applicable to low-power BLDC motor drives.

REFERENCES

[1]   C. L. Xia, Permanent Magnet Brushless DC Motor Drives and Controls. Hoboken, NJ, USA: Wiley, 2012.

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

[3]   Y. Chen, C. Chiu, Y. Jhang, Z. Tang, and R. Liang, “A driver for the singlephase brushless dc fan motor with hybrid winding structure,” IEEE Trans. Ind. Electron., vol. 60, no. 10, pp. 4369–4375, Oct. 2013.

[4]    X. Huang, A. Goodman, C. Gerada, Y. Fang, and Q. Lu, “A single sided matrix converter drive for a brushless dc motor in aerospace applications,” IEEE Trans. Ind. Electron., vol. 59, no. 9, pp. 3542–3552, Sep. 2012.

[5]   H. A. Toliyat and S. Campbell, DSP-Based Electromechanical Motion Control. Boca Raton, FL, USA: CRC Press, 2004..

Speed Control of BLDC Motor Using Fuzzy Logic Controller Based on Sensorless Technique

 ABSTRACT

Brushless dc (BLDC) motors are very popular and are replacing brush motors in numerous applications due to its superior electrical and mechanical characteristics owing to its trouble free construction. This paper presents the BLDC motor sensorless speed control system with fuzzy logic implementation. The sensorless techniques based on the back EMF sensing and the rotor position detection with a high starting torque is suggested. The rotor position is aligned at standstill for without an additional sensor. Also, the stator current can be easily adjusted by modulating the pulse width of the switching devices during alignment which will be helpful to reduce cost and complexity of the drive system without compromising the performance. The design analysis and simulation of the proposed system is done using MATLAB version 2010a and the simulation results of sensored drive using PI controller and sensorless drive using proposed methods are analyzed.

KEYWORDS:

1.       Brushless dc motor

2.      Hall sensored drive

3.      PI controller

4.      Back EMF sensorless drive

5.      Fuzzy controller

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1.Proposed block diagram of sensorless speed control of BLDC motor.

EXPECTED SIMULATION RESULTS:

Fig. 2(a) Variation of Back EMF signal with reference set at 1400 rpm

Fig. 2(b) Variation of stator current with reference set at 1400 rpm.

Fig. 3.Generated pulse from fuzzy logic controller.

Fig. 4(a) Speed response of sensored drive technique using PI controller.

Fig. 4(b) Speed response of sensorless drive technique using PI controller.

Fig. 4(c) Speed response of sensorless drive technique using fuzzy logic controller.

Fig. 5(a) Variation of Electromagnetic torque with reference set at 1400 rpm under sensorless drive using PI controller.

Fig. 5(b) Variation of Electromagnetic torque with reference set at 1400rpm under sensorless drive using fuzzy logic controller.

CONCLUSION

Sensorless speed control of BLDC motor drive with fuzzy logic implementation based on comparator with zero crossing detection have been experimented using MATLAB and evaluation of results are observed. The simulation results have shown that speed response of the BLDC motor can be controlled without sensors and also reduces the torque ripple. The results obtained from sensorless speed control of BLDC motor demonstrates that the system is less cost compared to sensored control and also good dynamic performance is obtained. This makes the motor suitable in application such as fuel pump, robotics and industrial automation. The proposed speed control scheme is robust, efficient and easy to implement in place of sensored applications.

REFERENCES

.

[1]   Nobuyuki Matsui, “Sensorless PM Brushless DC Motor Drives”, IEEE Trans. on Industrial Electronics, Vol.43, No.2,pp.300-308, April 1996.

[2]    Champa.P, Somasiri.P, Wipauramonton.P and Nakmahachalasint.P, “Initial Rotor Position Estimation for Sensorless Brushless DC Drives”, IEEE Trans. on Ind. Applications, Vol.45,No.4, pp.1318-1324,July 2009.

[3]   Somanatham.R, Prasad.P.V.N, Rajkumar.A.D, “Modelling and Simulation of Sensorless Control of PMBLDC Motor Using Zero-Crossing Back EMF Detection” IEEE SPEEDAM 2006 International Symposium on Power Electronics, Drives, Automotive and Motion.

[4]   Bimal K Bose, “Modern Power Electronics and AC Drives”, Pearson Education Asia 2002.

[5]    Miller. T.J.E., “Brushless permanent magnet and reluctance motor drives ", Clarendon Press, Oxford, 1989.

Novel Back EMF Zero Difference Point Detection Based Sensorless Technique for BLDC Motor

ABSTRACT

In this paper a novel position sensorless scheme named Back EMF Zero Difference Point (ZDP) detection has been proposed for six-switch VSI converter fed permanent magnet BLDC motor. This technique is based on the comparison of back EMFs and detection of the points in the back EMF waveforms where they cross each other or in other words they are equal. Commutation point is achieved exactly at the same instant when the difference of back EMFs of any two phases becomes zero. The simulation study has been carried out for the proposed sensorless scheme. The proposed sensorless scheme has the excellent performance from zero to the extra high speed. The method needs no additional delay circuit as used for calculation of commutation point from back EMF ZCP and involves less calculation burden. The method is fault tolerant and accurate even in the case of noise in measurement (or estimation) of phase back EMFs. A nonzero threshold value proportional to input voltage (or reference speed) is used for overcoming the problem due to quantization and sampling for digital implementation. This method proves to be excellent substitute of hall sensing scheme as it also senses at zero speed.

KEYWORDS:

1.      BLDC motor

2.      Back EMF ZDP

3.      Commutation

4.      Sensorless control

5.      Zero difference point.

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig.1 VSI fed BLDC motor with indirect Back EMF detection scheme

EXPECTED SIMULATION RESULTS:

Fig.2. Phase Back EMF ZDPs, switching signals, counter output and triggering sequence signals.

Fig.3. Steady state operation at the low speed of 600 rpm.

Fig.4. performance of proposed sensorless scheme at 17000 rpm

Fig.5. Noise immune performance during steady state operation for reference speed of 17000rpm.

Fig.6. sensing fault occurs at 0.5 second in the measurement of phase-B back EMF.

Fig.7. speed increases when sensing fault occurs (here phase-B sensing fault

CONCLUSION

In the proposed Back EMF Zero Difference Point (ZDP) detection method, the very first commutation signal is achieved at starting itself i.e. one step before the ZCP method, which proves the superiority of the method. The back EMF for the proposed scheme can be applied to various existing back EMF detection or estimation techniques. This technique is insensitive to the inherent noise in measurement (or estimation) of back EMF. This method does not need extra circuitry as needed for delay after ZCP for getting commutation point, thereby less computational complexity is involved. The speed (or input voltage) proportional threshold used for avoiding uncertainty in the zero difference of back EMF, sets its scope of wide usability in precise operation from zero to extra high speed. Operation at initial zero back EMF is the main strength of this method and it doesn’t necessitate separate starting techniques. Speed response at transient period is 0.15 ms faster than previous methods for identical motor parameters.

REFERENCES

[1]   M.V.Kesava Rao, Department of Electrical technology, IISc Bangalore, ‘‘Brush Contact Drops in DC machines’’, Accepted 25-6-1934, Bangalore Press.

[2]    Y.S. Jeon, H.S. Mok, G.H. Choe, D.K. Kim, J.S. Ryu, “A New Simulation Model of BLDC Motor with Real Back EMF waveform”, 7 th workshop on Computers in power Electronics , 2000 (COMPEL 2000), page 217- 220.

[3]   Padmaja yedmale, “Brushless DC (BLDC) Motor Fundamentals”, AN885, 2003 Microchip Technology.

[4]    S. Tara , Syfullah Khan Md “Simulation of sensorless operation of BLDC motor based on the zero cross detection from the line voltage” International Journal of Advanced Research in Electrical Electronics and Instrumentation Engineering, vol 2, issue 12 , December 2013, ISSN 2320-3765.

J. R. Frus and B. C. Kuo, “Closed-loop control of step motors using waveform detection,” in Proc. Int. Conf. Stepping Motors and Systems, Leeds, U.K., 1976, pp. 77–84.

Power Quality Improvement and Mitigation Case Study Using Distributed Power Flow Controller

ABSTRACT

According to growth of electricity demand and the increased number of non-linear loads in power grids, providing a high quality electrical power should be considered. In this paper, voltage sag and swell of the power quality issues are studied and distributed power flow controller (DPFC) is used to mitigate the voltage deviation and improve power quality. The DPFC is a new FACTS device, which its structure is similar to unified power flow controller (UPFC). In spite of UPFC, in DPFC the common dc-link between the shunt and series converters is eliminated and three-phase series converter is divided to several single-phase series distributed converters through the line. The case study contains a DPFC sited in a single-machine infinite bus power system including two parallel transmission lines, which simulated in MATLAB/Simulink environment. The presented simulation results validate the DPFC ability to improve the power quality.

KEYWORDS:

1.      FACTS

2.      Power Quality

3.      Sag and Swell Mitigation

4.      Distributed Power Flow Controller

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. The DPFC Structure

EXPECTED SIMULATION RESULTS:

Fig. 2. Three-phase load voltage sag waveform

Fig. 3. Mitigation of three-phase load voltage sag with DPFC

Fig. 4. Three-phase load current swell waveform without DPFC

Fig. 5. Mitigation of three-phase load current swell with DPFC

Fig. 6. Total harmonic distortion of load voltage without DPFC

Fig. 7. Total harmonic distortion of load voltage with DPFC

CONCLUSION

To improve power quality in the power transmission system, there are some effective methods. In this paper, the voltage sag and swell mitigation, using a new FACTS device called distributed power flow controller (DPFC) is presented. The DPFC structure is similar to unified power flow controller (UPFC) and has a same control capability to balance the line parameters, i.e., line impedance, transmission angle, and bus voltage magnitude. However, the DPFC offers some advantages, in comparison with UPFC, such as high control capability, high reliability, and low cost. The DPFC is modeled and three control loops, i.e., central controller, series control, and shunt control are design. The system under study is a single machine infinite-bus system, with and without DPFC. To simulate the dynamic performance, a three-phase fault is considered near the load. It is shown that the DPFC gives an acceptable performance in power quality mitigation and power flow control.

REFERENCES

[1]   S. Masoud Barakati, Arash Khoshkbar Sadigh and Ehsan Mokhtarpour, “Voltage Sag and Swell Compensation with DVR Based on Asymmetrical Cascade Multicell Converter” , North American Power Symposium (NAPS), pp.1 – 7, 2011

[2]   Alexander Eigels Emanuel, John A. McNeill “Electric Power Quality”. Annu. Rev. Energy Environ 1997, pp. 263-303.

[3]    I Nita R. Patne, Krishna L. Thakre “Factor Affecting Characteristics Of Voltage Sag Due to Fault in the Power System” Serbian Journal Of Electrical engineering. vol. 5, no.1, May2008, pp. 171-182.

[4]   J. R. Enslin, “Unified approach to power quality mitigation,” in Proc. IEEE Int. Symp. Industrial Electronics (ISIE ’98), vol. 1, 1998, pp. 8– 20.

[5]    B. Singh, K. Al-Haddad, and A. Chandra, “A review of active filters for power quality improvement,” IEEE Trans. Ind. Electron. vol. 46, no. 5, pp. 960–971, 1999.

Designing of Multilevel DPFC to Improve Power Quality

ABSTRACT

According to growth of electricity demand and the increased number of non-linear loads in power grids, providing a high quality electrical power should be considered. In this paper, Enhancement of power quality by using fuzzy based multilevel power flow controller (DPFC) is proposed. The DPFC is a new FACTS device, which its structure is similar to unified power flow controller (UPFC). In spite of UPFC, in DPFC the common dc-link between the shunt and series converters is eliminated and three-phase series converter is divided to several single-phase series distributed converters through the line. This eventually enables the DPFC to fully control all power system parameters. It, also, increases the reliability of the device and reduces its cost simultaneously. In recent years multi level inverters are used high power and high voltage applications .Multilevel inverter output voltage produce a staircase output waveform, this waveform look like a sinusoidal waveform leads to reduction in Harmonics. Fuzzy Logic is used for optimal designing of controller parameters. Application of Fuzzy Multilevel DPFC for reduction of Total Harmonic Distortion was presented. The simulation results show the improvement of power quality using DPFC with Fuzzy logic controller.

KEYWORDS:

1.      FACTS

2.      Power Quality

3.      Multi Level Inverters

4.      Fuzzy Logic

5.      Distributed Power Flow Controller component

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1: The DPFC Structure

EXPECTED SIMULATION RESULTS:

Fig.2: 5 Level Voltage Waveform

Fig.3: Three Phase output Voltage and Current Waveform

Fig.4: Supply Voltage and Current Waveform with unity PF

Fig.5: THD with out fuzzy

Fig.6: THD with fuzzy

CONCLUSION

In this paper Fuzzy Logic Controller technique based distributed power flow controller (DPFC) with multilevel voltage source converter (VSC) is proposed. The presented DPFC control system can regulate active and reactive power flow of the transmission line. We are reducing the THD value from 24.84% to 0.41% by using this technic as shown in fig’s (12) & (13).The series converter of the DPFC employs the DFACTS concept, which uses multiple converters instead of one large-size converter. The reliability of the DPFC is greatly increased because of the redundancy of the series converters. The total cost of the DPFC is also much lower than the UPFC, because no high-voltage isolation is required at the series converter part and the rating of the components are low. Also results show the valid improvement in Power Quality using Fuzzy Logic based Multilevel DPFC.

REFERENCES

[1]   K Chandrasekaran, P A Vengkatachalam, Mohd Noh Karsiti and K S Rama Rao, “Mitigation of Power Quality Disturbances”, Journal of Theoretical and Applied Information Technology, Vol.8, No.2, pp.105- 116, 2009

[2]    Priyanka Chhabra, “Study of Different Methods for Enhancing Power Quality Problems”, International Journal of Current Engineering and Technology, Vol.3, No.2, pp.403-410, 2013

[3]    Bindeshwar Singh, Indresh Yadav and Dilip Kumar, “Mitigation of Power Quality Problems Using FACTS Controllers in an Integrated Power System Environment: A Comprehensive Survey”, International Journal of Computer Science and Artificial Intelligence, Vol.1, No.1, pp.1-12, 2011

[4]    Ganesh Prasad Reddy and K Ramesh Reddy, “Power Quality Improvement Using Neural Network Controller Based Cascaded HBridge Multilevel Inverter Type D-STATCOM”, International Conference on Computer Communication and Informatics, 2012

[5]   Lin Xu and Yang Han, “Effective Controller Design for the Cascaded Hbridge Multilevel DSTATCOM for Reactive Compensation in Distribution Utilities”, Elektrotehniski Vestnik, Vol.78, No.4, pp.229- 235, 2011