Power Quality Improvement of PMSG Based DG Set Feeding Three-Phase Loads

ABSTRACT:

This paper presents power quality improvement of PMSG (Permanent Magnet Synchronous Generator) based DG (Diesel Generator) set feeding three-phase loads using STATCOM (Static Compensator). A 3-leg VSC (Voltage Source Converter) with a capacitor on the DC link is used as STATCOM. The reference source currents for the system are estimated using an Adaline based control algorithm. A PWM (Pulse Width Modulation) current controller is using for generation of gating pulses of IGBTs (Insulated Gate Bipolar Transistors) of three leg VSC of the STATCOM. The STATCOM is able to provide voltage control, harmonics elimination, power factor improvement, load balancing and load compensation. The performance of the system is experimentally tested on various types of loads under steady state and dynamic conditions. A 3-phase induction motor with variable frequency drive is used as a prototype of diesel engine with the speed regulation. Therefore, the DG set is run at constant speed so that the frequency of supply remains constant irrespective of loading condition.

KEYWORDS:

1.      STATCOM

2.      VSC

3.      IGBTs

4.      PMSG

5.      PWM

6.      DG Set

7.      Power Quality

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1 Configuration of PMSG based DG set feeding three phase loads.

EXPECTED SIMULATION RESULTS:

Fig. 2. Dynamic performance at linear loads (a) v_sab, i_sa,i_sb and i_sc ,(b) v_sab, i_La,i_Lb and i_Lc (c) V_dc, i_sa,i_La and i_Ca

CONCLUSION:

The STATCOM has improved the power quality of the PMSG based DG set in terms voltage control, harmonics elimination and load balancing. Under linear loads, there has been negligible voltage variation (From 219.1 V to 220.9 V) and in case of nonlinear load, the voltage increases to 221 V. Thus, the STATCOM has been found capable to maintain the terminal voltage of DG set within ± 0.5% (220 ±1 V) under different linear and nonlinear loads.

Under nonlinear loads, the load current of DG set is a quasi square with a THD of 24.4 %. The STATCOM has been found capable to eliminate these harmonics and thus the THD of source currents has been limited to 3.9 % and the THD of terminal voltage has been observed of the order of 1.8%. Therefore, the THDs of source voltage and currents have been maintained well within limits of IEEE-519 standard under nonlinear load.

It has also been found that the STATCOM maintains balanced source currents when the load is highly unbalanced due to removal of load from phase ‘c’. The load balancing has  also been achieved by proposed system with reduced stress on the winding of the generator.

The proposed system is a constant speed DG set so there is no provision of frequency control in the control algorithm.

However, the speed control mechanism of prototype of the diesel engine is able to maintain the frequency of the supply almost at 50 Hz with small variation of ±0.2 %.

Therefore, the proposed PMSG based DG set along with STATCOM can be used for feeding linear and nonlinear balanced and unbalanced loads. The proposed PMSG based DG set has also inherent advantages of low maintenance, high efficiency and rugged construction over a conventional wound field synchronous generator based DG set.

REFERENCES:

[1] Xibo Yuan; Fei Wang; Boroyevich, D.; Yongdong Li; Burgos, R., "DC-link Voltage Control of a Full Power Converter for Wind Generator Operating in Weak-Grid Systems," IEEE Transactions on Power Electronics, vol.24, no.9, pp.2178-2192, Sept. 2009.

[2] Li Shuhui, T.A. Haskew, R. P. Swatloski and W. Gathings, "Optimal and Direct-Current Vector Control of Direct-Driven PMSG Wind Turbines," IEEE Trans. Power Electronics, vol.27, no.5, pp.2325-2337, May 2012.

[3] M. Singh and A. Chandra, "Application of Adaptive Network-Based Fuzzy Inference System for Sensorless Control of PMSG-Based Wind Turbine With Nonlinear-Load-Compensation Capabilities," IEEE Trans. Power Electronics, vol.26, no.1, pp.165-175, Jan. 2011.

[4] A. Rajaei, M. Mohamadian and A. Yazdian Varjani, "Vienna-Rectifier-Based Direct Torque Control of PMSG for Wind Energy Application," IEEE Trans. Industrial Elect., vol.60, no.7, pp.2919-2929, July 2013.

[5] Mihai Comanescu, A. Keyhani and Dai Min, "Design and analysis of 42-V permanent-magnet generator for automotive applications," IEEE Trans. Energy Conversion, vol.18, no.1, pp.107-112, Mar 2003.

Power Factor Correction in Bridgeless-Luo Converter Fed BLDC Motor Drive

ABSTRACT:

This paper presents a power factor correction (PFC) based bridgeless-Luo (BL-Luo) converter fed brushless DC (BLDC) motor drive. A single voltage sensor is used for the speed control of BLDC motor and PFC at AC mains. The voltage follower control is used for a BL-Luo converter operating in discontinuous inductor current mode (DICM). The speed of the BLDC motor is controlled by an approach of variable DC link voltage, which allows a low frequency switching of voltage source inverter (VSI) for electronic commutation of BLDC motor; thus offers reduced switching losses. The proposed BLDC motor drive is designed to operate over a wide range of speed control with an improved power quality at AC mains. The power quality indices thus obtained are under the recommended limits of IEC 61000-3-2. The performance of the proposed drive is validated with test results obtained on a developed prototype of the drive.

KEYWORDS:

1.      Bridgeless Luo Converter

2.       Brushless DC motor

3.      Power Factor Correction

4.      Power Quality

5.      Voltage Source Inverter

SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig. 1. Proposed PFC BL-Luo Converter fed BLDC motor drive.

EXPECTED SIMULATION RESULTS:

Fig. 2. Test results of proposed BLDC motor drive (a) At rated load  torque on BLDC motor with Vdc=50V and Vs=220V, (b) At rated load torque on BLDC motor with Vdc=200V and Vs=220V

Fig. 3. Test results of proposed BLDC motor drive showing (a) iLi1, iLo1, VC1 with Vs, (b) PFC converter’s switch voltage and current at rated load torque on BLDC motor (c) Enlarged waveforms of PFC converter’s switch voltage and current.

Fig. 4. Test results of proposed BLDC motor drive showing dynamic performance (a) during starting at 50V, (b) during change in DC link voltage from 100V to 150V, (c) during change in supply voltage from

250 to 180V.

CONCLUSION:

A PFC based BL-Luo converter fed BLDC motor drive has been proposed for wide range of speeds and supply voltages. A single voltage sensor based speed control of BLDC motor using a concept of variable DC link voltage has been used. The PFC BL-Luo converter has been designed to operate in DICM and to act as an inherent power factor preregulator. An electronic commutation of the BLDC motor has been used which utilizes a low frequency operation of VSI for reduced switching losses. The proposed BLDC motor drive has been designed and its performance is simulated in MATLAB/Simulink environment for achieving an improved power quality over wide range of speed control. Finally, the performance of proposed drive has been verified experimentally on a developed hardware prototype. A satisfactory performance of proposed drive has been achieved and is a recommended solution for low power applications.

REFERENCES:

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

[2] T. Kenjo and S. Nagamori, Permanent Magnet Brushless DC Motors, Clarendon Press, Oxford, 1985.

[3] R. Krishnan, Electric Motor Drives: Modeling, Analysis and Control, Pearson Education, India, 2001.

[4] T. J Sokira and W. Jaffe, Brushless DC Motors: Electronic Commutation and Control, Tab Books, USA, 1989.

[5] H. A. Toliyat and S. Campbell, DSP-based Electromechanical Motion Control, CRC Press, New York, 2004.

Brushless DC motor drive with power factor regulation using Landsman converter

ABSTRACT:

This study presents a novel configuration of power factor regulation (PFR)-based Landsman converter feeding a brushless DC motor (BLDCM) drive for low-power (400 W) white goods applications. The speed control of the drive is achieved through adjusting the DC bus voltage of voltage source inverter (VSI) feeding to a BLDCM. Moreover, lowfrequency switching signals are used for electronic commutation of BLDCM, which reduces the switching power losses of six solid-state switches of VSI. This Landsman converter-based front-end power factor corrector operating in discontinuous inductor current mode is used to control DC bus voltage and PFR is achieved inherently. The DC bus voltage of the drive is controlled by using a single DC voltage sensor. For evaluating the performance of proposed drive, a prototype is developed in the laboratory. The performance of the BLDCM is also analysed for its operation at varying AC mains voltage (90–265 V). Experiential results for power quality indices are found within the limits of power quality standard IEC 61000-3-2.

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1Circuit configurations of a PFR based

 Proposed drive scheme of a Landsman converter fed PMBLDCM drive

 EXPECTED SIMULATION RESULTS:

Fig. 2 Performance of proposed drive at rated torque on motor

a Steady-state performance of the proposed BLDCM drive at rated load on BLDCM with DC-link voltage as 200 V and supply voltage as 220 V

b–d Obtained power quality indices

Fig. 3 Performance of proposed drive at rated load on motor

a Steady-state performance of the proposed BLDCM drive at rated load on BLDCM with DC-link voltage as 60 V and supply voltage as 220 V

b–d Obtained power quality indices

Fig. 4 Performance of PFR-based Landsman converter

a Input and output inductor’s currents and intermediate capacitor’s waveforms

b Current and voltage stress on a PFR switch at rated load on BLDCM at rated condition

Fig. 5 Dynamic performances of the proposed BLDCM drive system during

a Starting at 60 V

b Speed control for variation in DC bus voltage from 100 to 150 V

c Load variation

d Supply voltage change from 260 to 210 V

CONCLUSION:

A PFR-based Landsman converter fed BLDCM drive has been proposed for the use in low power household appliances. Adjustable voltage control of DC bus of VSI has been used to control the speed of BLDCM which eventually has given the freedom to operate the VSI in low frequency switching operation for minimum switching losses. A front-end Landsman converter-based PFR operating in DICM has been applied for double objectives of DC bus voltage control and achieving a UPF at AC supply. Resulted performance for presented drive has been found quite satisfactory for its operation at variation of speed over a wide range. A prototype of Landsman-based BLDCM drive has been implemented with acceptable test results for its operation over complete speed range and its operation over universal AC mains. The stress of the PFR converter switch has been evaluated to conclude its feasibility. The obtained power quality parameters are found within the limit of various international standards like as IEC 61000-3-2.

REFERENCES:

1 Gieras, J.F., Wing, M.: ‘Permanent magnet motor technology-design and application’ (Marcel Dekker Inc., New York, 2011)

2 Xia, C.L.: ‘Permanent magnet brushless DC motor drives and controls’ (Wiley Press, Beijing, 2012)

3 Zhu, Z.Q., Howe, D.: ‘Electrical machines and drives for electric, hybrid, and fuel cell vehicles’, IEEE Proc., 2007, 95, (4), pp. 746–765

4 Sozer, Y., Torrey, D.A., Mese, E.: ‘Adaptive predictive current control technique for permanent magnet synchronous motors’, IET Power Electron., 2013, 6, pp. 9–19

5 Hung, C.W., Lin, C.T., Liu, C.W., et al.: ‘A variable-sampling controller for brushless DC motor drives with low-resolution position sensors’, IEEE Trans.Ind. Electron., 2007, 54, (5), pp. 2846–2852

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.