Commutation Torque Ripple Reduction in BLDC Motor Using Modified SEPIC Converter and Three-level NPC Inverter

ABSTRACT

This paper presents a new power converter topology to suppress the torque ripple due to the phase current commutation of a brushless DC motor (BLDCM) drive system. A combination of a 3-level diode clamped multilevel inverter (3-level DCMLI), a modified single-ended primary-inductor converter (SEPIC), and a dc-bus voltage selector circuit are employed in the proposed torque ripple suppression circuit. For efficient suppression of torque pulsation, the dc-bus voltage selector circuit is used to apply the regulated dc-bus voltage from the modified SEPIC converter during the commutation interval. In order to further mitigate the torque ripple pulsation, the 3-level DCMLI is used in the proposed circuit. Finally, simulation and experimental results show that the proposed topology is an attractive option to reduce the commutation torque ripple significantly at low and high speed applications.

KEYWORDS

1.      Brushless direct current motor (BLDCM),

2.      Dc-bus voltage control

3.       Modified single-ended primary-inductor converter

4.       Level diode clamped multilevel inverter (3-level DCMLI)

5.       Torque ripple

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

                                Fig. 1. Proposed converter topology with a dc-bus voltage selector circuit for BLDCM

EXPECTED SIMULATION RESULTS

Fig. 2. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm with 5 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 3 Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm with 5 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 4 Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm with 20 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and switch a selection circuit. (d) BLDCM fed by proposed topology.

Fig. 5 Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm with 20 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology

Fig. 6. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm with 80 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 7 Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm with 80 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology

                                                                                                           

CONCLUSION

In this paper, a commutation torque ripple reduction circuit has been proposed using 3-level DCMLI with modified SEPIC converter and a dc-bus voltage selector circuit. A laboratory-built drive system has been tested to verify the proposed converter topology. The suggested dc-bus voltage control strategy is more effective in torque ripple reduction in the commutation interval. The proposed topology accomplishes the successful reduction of torque ripple in the commutation period and experimental results are presented to compare the performance of the proposed control technique with the conventional 2-level inverter, 3-level DCMLI, 2-level inverter with SEPIC converter and the switch selection circuit-fed BLDCM. In order to obtain significant torque ripple suppression, quietness and higher efficiency, 3-level DCMLI with modified SEPIC converter and the voltage selector circuit is a most suitable choice to obtain high-performance operation of BLDCM. The proposed topology may be used for the torque ripple suppression of BLDCM with the very low stator winding inductance.

REFERENCES

[1] N. Milivojevic, M. Krishnamurthy, Y. Gurkaynak, A. Sathyan, Y.-J. Lee, and A. Emadi, “Stability analysis of FPGA-based control of brushless DC motors and generators using digital PWM technique,” IEEE Trans. Ind. Electron., vol. 59, no. 1, pp. 343–351, Jan. 2012.

[2] 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.

[3] X. Huang, A. Goodman, C. Gerada, Y. Fang, and Q. Lu, "Design of a five-phase brushless DC motor for a safety critical aerospace application,” IEEE Trans. Ind. Electron., vol. 59, no. 9, pp. 3532-3541, Sep. 2012.

[4] J.-G. Lee, C.-S. Park, J.-J. Lee, G. H. Lee, H.-I. Cho, and J.-P. Hong, "Characteristic analysis of brushless motor condering drive type,” KIEE, pp. 589-591, Jul. 2002.

[5] T. H. Kim and M. Ehsani, “Sensorless control of BLDC motors from near-zero to high speeds,” IEEE Trans. Power Electron., vol. 19, no. 6, pp. 1635–1645, Nov. 2004.

Solar PV Array Fed Brushless DC Motor Driven Water Pump

ABSTRACT:

This work deals with the utilization of solar photovoltaic (SPV) energy in the brushless DC (BLDC) motor driven water pump. A DC-DC boost converter, used as an intermediate power conditioning unit plays a vital role in efficiency enhancement of SPV array and soft starting of the BLDC motor with proper control. The speed control of BLDC motor is performed by PWM (Pulse Width Modulation) control of the voltage source inverter (VSI) using DC link voltage regulator. No additional control or current sensing element is required for speed control. The behavior of proposed pumping system is demonstrated by evaluating its various performances through MATLAB/simulink based simulation study.

KEYWORDS:

1.      Solar PV

2.       BLDC motor

3.       Boost converter

4.       Soft starting

5.      PWM

6.       VSI

7.      Speed control

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig.1 Configuration of PV array fed BLDC motor-pump.

 EXPECTED SIMULATION RESULTS:

Fig.2 Starting and steady state performances of solar PV array

Fig.3 Starting and steady state performance of boost DC-DC converter

Fig.4 Starting and steady state performance of brushless DC motor-pump

Fig.5 Dynamic performance of solar PV array.

Fig.6 Dynamic performance of boost DC-DC converter

Fig.7 Dynamic performance of brushless DC motor – pump

CONCLUSION:

The SPV Array fed boost converter based BLDC motor driven water pump has been proposed and its suitability has been demonstrated by analyzing its various performance indices using MATLAB based simulation study. A simple, efficient and economical method for speed control of BLDC motor has been suggested, which has offered absolute elimination of current sensing elements. The proper selection of SPV array has made the boost converter capable of tracking MPP irrespective of weather conditions. An optimum design of the boost converter has been presented. The safe starting of brushless DC motor has been achieved without any additional control. The desired performance of proposed system even at 20% of standard solar irradiance has justified its suitability for solar PV based water pumping.

REFERENCES:

[1] R. Kumar and B. Singh, “Solar PV array fed Cuk converter-VSI controlled BLDC motor drive for water pumping,” 6th IEEE Power India Int. Conf. (PIICON), 5-7 Dec. 2014, pp. 1-7.

[2] M. A. Elgendy, B. Zahawi and D. J. Atkinson, “Assessment of the Incremental Conductance Maximum Power Point Tracking Algorithm,” IEEE Trans. Sustain. Energy, vol.4, no.1, pp.108-117, Jan. 2013.

[3] J.V. Mapurunga Caracas, G. De Carvalho Farias, L.F. Moreira Teixeira and L.A. De Souza Ribeiro, “Implementation of a High-Efficiency, High-Lifetime, and Low-Cost Converter for an Autonomous Photovoltaic Water Pumping System,” IEEE Trans. Ind. Appl., vol. 50, no. 1, pp. 631-641, Jan.-Feb. 2014.

[4] N. Mohan, T. M. Undeland and W. P. Robbins, Power Electronics: Converters, Applications and Design, 3rd ed. New Delhi, India: John Wiley & Sons Inc., 2010.

[5] M. H. Rashid, Power Electronics Handbook: Devices, Circuits, and Applications,” 3rd ed. Oxford, UK: Elsevier Inc., 2011.

Commutation Torque Ripple Reduction in BLDC Motor Using Modified SEPIC Converter and Three-level NPC Inverter

ABSTRACT:

This paper presents a new power converter topology to suppress the torque ripple due to the phase current commutation of a brushless DC motor (BLDCM) drive system. A combination of a 3-level diode clamped multilevel inverter (3-level DCMLI), a modified single-ended primary-inductor converter (SEPIC), and a dc-bus voltage selector circuit are employed in the proposed torque ripple suppression circuit. For efficient suppression of torque pulsation, the dc-bus voltage selector circuit is used to apply the regulated dc-bus voltage from the modified SEPIC converter during the commutation interval. In order to further mitigate the torque ripple pulsation, the 3-level DCMLI is used in the proposed circuit. Finally, simulation and experimental results show that the proposed topology is an attractive option to reduce the commutation torque ripple significantly at low and high speed applications.

KEYWORDS:

1.      Brushless direct current motor (BLDCM)

2.       Dc-bus voltage control

3.       Modified single-ended primary-inductor converter

4.       3-level diode clamped multilevel inverter (3-level DCMLI)

5.       Torque ripple

SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig. 1. Proposed converter topology with a dc-bus voltage selector circuit for BLDCM

EXPECTED SIMULATION RESULTS:

Fig. 2. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm with 5 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 3. Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm with 5 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 4. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm with 20 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and switch a selection circuit. (d) BLDCM fed by proposed topology.

Fig. 5. Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm with 20 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 6. Simulated waveforms of phase current and torque at 1000 rpm and 0.825 Nm with 80 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

Fig. 7. Simulated waveforms of phase current and torque at 6000 rpm and 0.825 Nm with 80 kHz switching frequency. (a) BLDCM fed by 2-level inverter. (b) BLDCM fed by 3-level DCMLI. (c) BLDCM fed by 2-level inverter with SEPIC converter and a switch selection circuit. (d) BLDCM fed by proposed topology.

CONCLUSION:

In this paper, a commutation torque ripple reduction circuit has been proposed using 3-level DCMLI with modified SEPIC converter and a dc-bus voltage selector circuit. A laboratory-built drive system has been tested to verify the proposed converter topology. The suggested dc-bus voltage control strategy is more effective in torque ripple reduction in the commutation interval. The proposed topology accomplishes the successful reduction of torque ripple in the commutation period and experimental results are presented to compare the performance of the proposed control technique with the conventional 2-level inverter, 3-level DCMLI, 2-level inverter with SEPIC converter and the switch selection circuit-fed BLDCM. In order to obtain significant torque ripple suppression, quietness and higher efficiency, 3-level DCMLI with modified SEPIC converter and the voltage selector circuit is a most suitable choice to obtain high-performance operation of BLDCM. The proposed topology may be used for the torque ripple suppression of BLDCM with the very low stator winding inductance.

REFERENCES:

[1] N. Milivojevic, M. Krishnamurthy, Y. Gurkaynak, A. Sathyan, Y.-J. Lee, and A. Emadi, “Stability analysis of FPGA-based control of brushless DC motors and generators using digital PWM technique,” IEEE Trans. Ind. Electron., vol. 59, no. 1, pp. 343–351, Jan. 2012.

[2] 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.

[3] X. Huang, A. Goodman, C. Gerada, Y. Fang, and Q. Lu, "Design of a five-phase brushless DC motor for a safety critical aerospace application,” IEEE Trans. Ind. Electron., vol. 59, no. 9, pp. 3532-3541, Sep. 2012.

[4] J.-G. Lee, C.-S. Park, J.-J. Lee, G. H. Lee, H.-I. Cho, and J.-P. Hong, "Characteristic analysis of brushless motor condering drive type,” KIEE, pp. 589-591, Jul. 2002.

[5] T. H. Kim and M. Ehsani, “Sensorless control of BLDC motors from near-zero to high speeds,” IEEE Trans. Power Electron., vol. 19, no. 6, pp. 1635–1645, Nov. 2004.

STATCOM-Based Voltage Regulator for Self-Excited Induction Generator Feeding Nonlinear Loads

ABSTRACT:

This paper deals with the performance analysis of a static compensator (STATCOM)-based voltage regulator for self-excited induction generators (SEIGs) supplying nonlinear loads. In practice, a number of loads are nonlinear in nature, and therefore, they inject harmonics in the generating systems. The SEIG’s performance, being a weak isolated system, is very much affected by these harmonics. The additional drawbacks of the SEIG are poor voltage regulation and that it requires an adjustable reactive power source with varying loads to maintain a constant terminal voltage. A three-phase insulated-gate-bipolar transistor- based current-controlled voltage source inverter working as STATCOM is used for harmonic elimination, and it provides the required reactive power for the SEIG, with varying loads to maintain a constant terminal voltage. A dynamic model of the SEIG–STATCOM feeding nonlinear loads using stationary d−q axes reference frame is developed for predicting the behaviour of the system under transient conditions. The simulated results show that SEIG terminal voltage is maintained constant, even with nonlinear balanced and unbalanced loads, and free from harmonics using STATCOM-based voltage regulator.

KEYWORDS:

1.      Harmonic elimination

2.       Load balancing

3.       Nonlinear loads

4.       Self-excited induction generator (SEIG)

5.       Static compensator (STATCOM)

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Schematic diagram of proposed scheme of SEIG–STATCOM system

CONTROL SYSTEM:

Fig.2 Control scheme of SEIG–STATCOM system.

EXPECTED SIMULATION RESULTS:

Fig. 3. Voltage buildup of SEIG and switching in STATCOM.

Fig. 4. Waveform of three-phase SEIG–STATCOM system supplying diode rectifier with resistive load change from no load, to three-phase (22 kW), to one-phase (15 kW), to three-phase (22 kW) loads, and to no load.

Fig. 5. Waveform of three-phase SEIG–STATCOM system supplying diode rectifier with capacitive filter and resistive load change from no load, to three-phase (15 kW), to one-phase (24 kW), to three-phase (15 kW) loads, and to no load.

Fig. 6. Waveforms of three-phase SEIG–STATCOM system supplying diode rectifier with capacitive filter and resistive load change from no load, to three-phase (15 kW), to three-phase (22 kW), to three-phase (15 kW) loads, and to no load.

Fig. 7. Waveforms of three-phase SEIG–STATCOM system supplying thyristorized rectifier with resistive load change from no load, to three-phase (18 kW) at 60◦ firing angle, to no load.

CONCLUSION:

It has been observed that the developed mathematical model of a three-phase SEIG–STATCOM is capable of simulating its performance while feeding nonlinear loads under transient conditions. From the simulated results, it has been found that the SEIG terminal voltage remains constant, with the sinusoidal feeding of the three-phase or single-phase rectifiers with resistive and with dc capacitive filter and resistive loads. When a single-phase rectifier load is connected, the STATCOM balances the unbalanced load currents, and the generator currents and voltage remain balanced and sinusoidal; therefore, the STATCOM acts as a load balancer. The rectifier-based nonlinear load generates the harmonics, which are also eliminated by STATCOM. Therefore, it is concluded that STATCOM acts as voltage regulator, load balancer, and harmonic eliminator, resulting in an SEIG system that is an ideal ac power-generating system.

REFERENCES:

[1] C. Grantham, D. Sutanto, and B. Mismail, “Steady state and transient analysis of self-excited induction generator,” Proc. Inst. Electr. Eng., vol. 136, no. 2, pp. 61–68, Mar. 1989.

[2] K. E. Hallenius, P. Vas, and J. E. Brown, “The analysis of saturated selfexcited asynchronous generator,” IEEE Trans. Energy Convers., vol. 6, no. 2, pp. 336–341, Jun. 1991.

[3] M. H. Salama and P. G. Holmes, “Transient and steady-state load performance of a stand-alone self-excited induction generator,” Proc. Inst. Electr. Eng.—Electr. Power Appl., vol. 143, no. 1, pp. 50–58, Jan. 1996.

[4] L. Wang and R. Y. Deng, “Transient performance of an isolated induction generator under unbalanced excitation capacitors,” IEEE Trans. Energy Convers., vol. 14, no. 4, pp. 887–893, Dec. 1999.

[5] S. K. Jain, J. D. Sharma, and S. P. Singh, “Transient performance of threephase self-excited induction generator during balanced and unbalanced faults,” Proc. Inst. Electr. Eng.—Generation Transmiss. Distrib., vol. 149, no. 1, pp. 50–57, Jan. 2002.