Single Stage Solar PV Fed Brushless DC Motor Driven Water Pump



In order to optimize the solar photovoltaic (PV) generated power using a maximum power point tracking (MPPT) technique, a DC-DC conversion stage is usually required in solar PV fed water pumping which is driven by a brushless DC (BLDC) motor. This power conversion stage leads to an increased cost, size, complexity and reduced efficiency. As a unique solution, this work addresses a single stage solar PV energy conversion system feeding a BLDC motor-pump, which eliminates the DC-DC conversion stage. A simple control technique capable of operating the solar PV array at its peak power using a common voltage source inverter (VSI), is proposed for BLDC motor control. The proposed control eliminates the BLDC motor phase current sensors. No supplementary control is associated for the speed control of motor-pump and its soft start. The speed is controlled through the optimum power of solar PV array. The suitability of proposed system is manifested through its performance evaluation using MATLAB/Simulink based simulated results and experimental validation on a developed prototype, under the practical operating conditions.


  1. MPPT
  2. Solar PV array
  3. BLDC motor
  4. Water pump
  5. VSI
  6. Soft starting
  7. Speed control




Fig.1 Proposed water pumping based on a single stage solar PV energy conversion system.


 Fig.2 Steady state and starting performance of (a) PV array and (b) motor pump, of proposed system at 1 kW/m2.

Fig.3 Steady state and starting response of (a) PV array and (b) motor-pump, of proposed system at 200 W/m2.

Fig.4 Dynamic performance of (a) PV array and (b) BLDC motor Pump ,of Proposed  water pumping system.

Fig. 5 Responses of (a) PV array and (b) BLDC motor, under partial shading


The proposed BLDC motor driven water pumping based on a single stage solar PV generation has been validated through a demonstration of its various steady state, starting and dynamic performances. The system has been simulated using the MATLAB toolboxes, and implemented on an experimental prototype. The topology of the proposed system has provided a DC-DC converter-less solution for PV fed brushless DC motor driven water pumping. Moreover, the motor phase current sensing elements have been eliminated, resulting in a simple and cost-effective drive. The other desired functions are the speed control without any additional circuit and a soft start of the motor-pump. A detailed comparative analysis of the proposed and the existing topologies has ultimately manifested the superiority of the proposed work.


[1] C. Jain and B. Singh, “An Adjustable DC Link Voltage Based Control of Multifunctional Grid Interfaced Solar PV System,” IEEE J. Emerg. Sel. Topics Power Electron., Early Access.

[2] A. A. A. Radwan and Y. A. R. I. Mohamed, “Power Synchronization Control for Grid-Connected Current-Source Inverter-Based Photovoltaic Systems,” IEEE Trans. Energy Convers., vol. 31, no. 3, pp. 1023-1036, Sept. 2016.

[3] P. Vithayasrichareon, G. Mills and I. F. MacGill, “Impact of Electric Vehicles and Solar PV on Future Generation Portfolio Investment,” IEEE Trans. Sustain. Energy, vol. 6, no. 3, pp. 899-908, July 2015.

[4] A. K. Mishra and B. Singh, “A single stage solar PV array based water pumping system using SRM drive,” IEEE Ind. Appl. Soc. Annu. Meeting, Portland, OR, 2016, pp. 1-8.

[5] S. Jain, A.K. Thopukara, R. Karampuri and V.T. Somasekhar, “A Single-Stage Photovoltaic System for a Dual-Inverter-Fed Open-End Winding Induction Motor Drive for Pumping Applications,” IEEE Trans. Power Electron., vol. 30, no. 9, pp. 4809 – 4818, Sept. 2015.

BLDC Motor Driven Solar PV Array Fed Water Pumping System Employing Zeta Converter


This paper proposes a simple, cost effective and efficient brushless DC (BLDC) motor drive for solar photovoltaic (SPV) array fed water pumping system. A zeta converter is utilized in order to extract the maximum available power from the SPV array. The proposed control algorithm eliminates phase current sensors and adapts a fundamental frequency switching of the voltage source inverter (VSI), thus avoiding the power losses due to high frequency switching. No additional control or circuitry is used for speed control of the BLDC motor. The speed is controlled through a variable DC link voltage of VSI. An appropriate control of zeta converter through the incremental conductance maximum power point tracking (INC-MPPT) algorithm offers soft starting of the BLDC motor. The proposed water pumping system is designed and modeled such that the performance is not affected under dynamic conditions. The suitability of proposed system at practical operating conditions is demonstrated through simulation results using MATLAB/ Simulink followed by an experimental validation.


  1. BLDC motor
  2. SPV array
  3. Water pump
  4. Zeta converter
  5. VSI




Fig.1 Configuration of proposed SPV array-Zeta converter fed BLDC motor drive for water pumping system.



Fig.2 Performances of the proposed SPV array based Zeta converter fed BLDC motor drive for water pumping system (a) SPV array variables, (b) Zeta converter variables, and (c) BLDC motor-pump variables.


The SPV array-zeta converter fed VSI-BLDC motor-pump for water pumping has been proposed and its suitability has been demonstrated by simulated results using MATLAB/Simulink and its sim-power-system toolbox. First, the proposed system has been designed logically to fulfil the various desired objectives and then modelled and simulated to examine the various performances under starting, dynamic and steady state conditions. The performance evaluation has justified the combination of zeta converter and BLDC motor drive for SPV array based water pumping. The system under study availed the various desired functions such as MPP extraction of the SPV array, soft starting of the BLDC motor, fundamental frequency switching of the VSI resulting in a reduced switching losses, reduced stress on IGBT switch and the components of zeta converter by operating it in continuous conduction mode and stable operation. Moreover, the proposed system has operated successfully even under the minimum solar irradiance.


[1] M. Uno and A. Kukita, “Single-Switch Voltage Equalizer Using Multi- Stacked Buck-Boost Converters for Partially-Shaded Photovoltaic Modules,” IEEE Transactions on Power Electronics, no. 99, 2014.

[2] R. Arulmurugan and N. Suthanthiravanitha, “Model and Design of A Fuzzy-Based Hopfield NN Tracking Controller for Standalone PV Applications,” Electr. Power Syst. Res. (2014). Available:

[3] S. Satapathy, K.M. Dash and B.C. Babu, “Variable Step Size MPPT Algorithm for Photo Voltaic Array Using Zeta Converter – A Comparative Analysis,” Students Conference on Engineering and Systems (SCES), pp.1-6, 12-14 April 2013.

[4] A. Trejos, C.A. Ramos-Paja and S. Serna, “Compensation of DC-Link Voltage Oscillations in Grid-Connected PV Systems Based on High Order DC/DC Converters,” IEEE International Symposium on Alternative Energies and Energy Quality (SIFAE), pp.1-6, 25-26 Oct. 2012.

[5] G. K. Dubey, Fundamentals of Electrical Drives, 2nd ed. New Delhi, India: Narosa Publishing House Pvt. Ltd., 2009.

A Comparative Study on the Speed Response of BLDC Motor Using Conventional PI Controller, Anti-windup PI Controller and Fuzzy Controller



Brushless dc motors (BLDC) are widely used for various applications because of high torque, high speed and smaller size. This type of motors are non linear in nature and are affected highly by the non-linearities like load disturbance. Speed control of this motor is traditionally handled by conventional PI and PID controllers. This paper presents the speed control of BLDC motor using anti wind up PI controller. Problems like rollover can arise in conventional PI controller due to saturation effect. In order to avoid such problems anti wind up schemes are introduced. As the fuzzy controller has the ability to control and as it is simple to calculate, a fuzzy controller is also designed for speed control of BLDC motor. The control and simulation of BLDC motor have been done using software MATLAB/SIMULINK. The simulation results using anti wind up PI controller and fuzzy controller are compared with PI controller.


  1. BLDC
  2. Speed response
  3. PI controller
  4. Fuzzy
  5. Anti windup




Fig.1. Simulation block diagram



 Fig.2. Speed response under no load

Fig.3. Speed response for step increase in speed

Fig.4. Speed response for step increase in speed

Fig.5. Speed response under loaded condition

Fig.6.Speed response under load condition


 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.


[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.


A Comparative Study of Speed Control of D.C. Brushless Motor Using PI and Fuzzy Controller



This paper presents an intelligent control architecture for a sensor based brushless DC motor. A BLDC motor is superior to a brushed DC motor, as it replaces the mechanical commutation unit with an electronic one; hence improving the dynamic characteristics, efficiency and reducing the noise level marginally. Conventionally a PI-controller is used for speed control purpose in many industrial BLDC motor drives. But the accuracy level obtained by the PI-controlled drive is insufficient for advanced sophisticated applications. So as a better choice, a fuzzy logic control technique is applied to this motor to achieve a greater accuracy in controlling the speed.


  1. Intelligent control
  2. BLDC motor
  3. Dynamic characteristics
  4. Accuracy
  5. Fuzzy logic



Fig. 1. Block diagram for speed control of BLDCM using PI controller.

Fig. 2. Block diagram of a fuzzy logic controlled BLDC motor drive.


                  Fig. 3. Speed response of PI controlled BLDC motor drive(Nref=1500 r.p.m)

Fig. 4. Speed response of fuzzy logic controlled BLDC motor drive (Nref=1500 r.p.m)

Fig. 5. Speed response of PI controlled BLDC motor drive(transition from 1500 r.p.m to 1400 r.p.m)

                         Fig. 6. Speed response of fuzzy logic controlled BLDC motor drive (transition from 1500 r.p.m to 1400 r.p.m)


In this paper we discussed the BLDC motor speed control using a fuzzy logic controller. A detailed analysis was done on fuzzification, fuzzy rules and defuzzification methods and lookup table was obtained by using fuzzy algorithm. The PI control scheme and fuzzy based PI scheme were simulated using MATLAB and compared. The dynamic response of speed in using FLC was better than only PI scheme. These results show that a PI based FLC technique is a better choice for BLDC motor drive and favors to widen its area of application in near future.


[1] Paul C. Krause, “Analysis of electric machinary”, McGraw-Hill, 1984.

[2] P.S. Bimbhra, “ Generalized Theory of Electrical Machines”, Khanna Publishers.

[3] P. Yedamale, Brushless DC (BLDC) Motor Fundamentals. Application Note 885, Microchip Technology Inc., Chandler, AZ,2003.

[4] Dutta, P.; Mahato, S.N., “Design of mathematical model and performance analysis of BLBLDC motor,” Control, Instrumentation, Energy and Communication (CIEC), 2014 International Conference on , vol., no., pp.457,461, Jan. 31 2014-Feb. 2 2014

[5] Ko, J.S.; Jae Gyu Hwang; Myung-Joong Youn, “Robust position control of BLDD motors using integral-proportional plus fuzzy logic controller,” Industrial Electronics, Control, and Instrumentation, 1993. Proceedings of the IECON ’93., International Conference on , vol., no., pp.213,218 vol.1, 15-19 Nov 1993

A Comparative Study of PI, Fuzzy and Hybrid PI Fuzzy Controller for Speed Control of Brushless DC Motor Drive


This paper presents the comparative study between PI, fuzzy and hybrid PI-Fuzzy controller for speed control of brushless dc (BLDC) motor. The control structure of the proposed drive system is described. The simulation results of the drive system for different operation modes are evaluated and compared. A fuzzy controller offers better speed response for start-up while PI controller has good compliance over variation of load torque but has slow settling response. Hybrid controller has an advantage of integrating a superiority of these two controllers for better control performances. Matlab/Simulink is used to carry out the simulation.

1. PI
2. Fuzzy
3. Hybrid Controller
4. BLDC Motor
5. Speed Control



Figure 1: Simulation model BLDC motor drive


Figure 2: PI controller

Figure 3: Fuzzy controller

Figure 4: Hybrid controller

Figure 5: Comparison of speed response

Figure 6: PI controller

Figure 7: Fuzzy controller

Figure 8: Hybrid controller

Figure 9: Comparison of speed response

From simulation results, it was shown that PI controller maintained the steady state accuracy while the fuzzy controller performed well in the case of sufficiently large reference input changes with shorter settling time. The hybrid controller has integrated both fuzzy controller and PI controller. During the large speed error, the fuzzy controller will be selected by switch. When the speed error is less than 0.28 rpm, the PI controller will be selected to maintain the high steady-state accuracy. The simulation results showed that the hybrid controller has incorporated advantage of both fuzzy and PI controller. As a conclusion, the hybrid controller has improved the dynamic performance of BLDC motor.
[1] F. Farkas, A. Zakharov and S.Z. Varga, “Speed and position controller for dc drives using fuzzy logic”, Studies in Applied Electromagnetics and Mechanics (Vol. 16): Applied Electromagnetics and Computational Technology II, Amsterdam: IOS Press, 2000.
[2] Zulkifilie Ibrahim and Emil Levi, “A comparative analysis of fuzzy logic and pi speed control in high-performance ac drives using experimental approach”, IEEE Trans. on Industry Applications 38(5): pg 1210-1218, 2002.
[3] L.S. Xuefang, F. Morel, A.M. Llor, B. Allard, J.-M. Retif, “Implementation of hybrid control for motor drives”, IEEE Trans. Industrial Electronics, vol.38, No. 5, pp. 1210-1218, Sep. 2002.
[4] Krishnan R, Permanent magnet synchronous and brushless DC motor drives, Boca Raton: CRC Press, 2010
[5] Lini Mathew and Vivek Kumar Pandey, “Design and deelopment of fuzzy logic controller to control the speed of permanent magnet synchronous motor”, JEEER, vol. 3(3), pp. 52-61, March 2011.

Control of BLDC Motor Based on Adaptive Fuzzy Logic PID Controller

This paper presents an Adaptive fuzzy logic PID controller for speed control of Brushless Direct current Motor drives which is widely used in various industrial systems, such as servo motor drives, medical, automobile and aerospace industry. BLDC motors were electronically commutated motor offer many advantages over Brushed DC Motor which includes increased efficiency, longer life, low volume and high torque. This paper presents an overview of performance of fuzzy PID controller and Adaptive fuzzy PID controller using Simulink model. Tuning Parameters and computing using Normal PID controller is difficult and also it does not give satisfied control characteristics when compare to Adaptive Fuzzy PID controller. From the Simulation results we verify that Adaptive Fuzzy PID controller give better control performance when compared to fuzzy PID controller. The software Package SIMULINK was used in control and Modelling of BLDC Motor.

1. Brushless DC motors (BLDCM)
2. Fuzzy PID controller
3. Adaptive Fuzzy PID controller


Fig.1. Speed control of BLDC motor


Fig.2. Speed characteristics with no load speed of 3000 rpm

Fig.3. Torque characteristics with no load speed of 3000 rpm

Fig. 4. Speed characteristics with no load step down speed of 3000- 2500 rpm

Fig.5. Torque characteristics with no load step down speed of 3000-2500 rpm

Fig.6. Speed characteristics with load speed of 3000 rpm

Fig.7. Torque characteristics with load speed of 3000 rpm



This paper presents the performance of fuzzy PID controller and Adaptive Fuzzy PID controller of BLDC motor for speed control using Simulink model. Combination of fuzzy control and conventional PID controller establishes an intelligent control, which regulates the control parameters depending upon the error. Two inputs and three outputs were used in this fuzzy adaptive PID controller. From the Simulation, BLDC motor speed control of Adaptive fuzzy PID controller had better performance than fuzzy PID controller for the same operation condition, mainly when BLDC motor operates in different speed and also BLDC motor speed to be constant when the load varies. Simulation results were also shows that fuzzy logic adaptive PID controller had lesser overshoot, faster response and better stability.
[1] Anjali.A.R “Control Of Three Phase BLDC Motor Using Fuzzy Logic Controller” International Journal of Engineering Research & Technology (IJERT), Vol. 2, Issue 7, July 2013.
[2] R. Kandiban, R. Arulmozhiyal “Design of Adaptive Fuzzy PID Controller for Speed control of BLDC Motor” International Journal of Soft Computing and Engineering ,Volume-2, Issue-1, March 2012.
[3] Uzair Ansari, Saqib Alam, Syed Minhaj un Nabi Jafri, “Modelling and Control of Three Phase BLDC Motor using PID with Genetic Algorithm”, UK Sim 13th International Conference on Modelling and Simulation,pp.189-194,2011
[4] R.Arulmozhiyal and K.Baskaran, “Implementation of Fuzzy PI Controller for Speed Control of Induction Motor Using FPGA”, Journal of Power Electronics, Vol.10, No.1, pp.65-71, Jan 2010.
[5] Vinod Kr Singh Patel, A.K.Pandey, “Modelling and Simulation of Brushless DC Motor Using PWM Control Technique”, International Journal of Engineering Research and Applications, Vol. 3, Issue 3, May-Jun 2013, pp.612-620.

Design and Implementation of a Novel Multilevel DC–AC Inverter



In this paper, a novel multilevel dc–ac inverter is proposed. The proposed multilevel inverter generates seven-level ac output voltage with the appropriate gate signals’ design. Also, the low-pass filter is used to reduce the total harmonic distortion of the sinusoidal output voltage. The switching losses and the voltage stress of power devices can be reduced in the proposed multilevel inverter. The operating principles of the proposed inverter and the voltage balancing method of input capacitors are discussed. Finally, a laboratory prototype multilevel inverter with 400-V input voltage and output 220 Vrms/2 kW is implemented. The multilevel inverter is controlled with sinusoidal pulse-width modulation (SPWM) by TMS320LF2407 digital signal processor (DSP). Experimental results show that the maximum efficiency is 96.9% and the full load efficiency is 94.6%.


  1. DC–AC inverter
  2. Digital signal processor (DSP)
  3. Maximum power point tracking (MPPT)
  4. Multilevel



Fig. 1. Block diagram of renewable system.


Fig. 2. Waveforms of vgs1, vab, vo, and io at 500 W.

Fig. 3. Output voltage harmonic spectrum of vab calculated by FFT.

Fig. 4. Output voltage harmonic spectrum of vo calculated by FFT

Fig. 5. Waveforms of vC2, vo, and io at 1000 W.

Fig. 6. Waveforms of vC2, vo, and io at 2000 W.

Fig. 7. Waveforms of vo and io at 400 VA.



A novel seven-level inverter was designed and implemented with DSP in this paper. The main idea of the proposed configuration is to reduce the number of power device. The reduction of power device is proved by comparing with traditional structures. Finally, a laboratory prototype of seven-level inverter with 400-V input voltage and output 220 Vrms/2kW is implemented. Experimental results show that the maximum efficiency is 96.9% and the full load efficiency is 94.6%.


[1] R. Gonzalez, E. Gubia, J. Lopez, and L. Marroyo, “Transformerless single-phase multilevel-based photovoltaic inverter,” IEEE Trans. Ind. Electron., vol. 55, no. 7, pp. 2694–2702, Jul. 2008.

[2] S. Daher, J. Schmid, and F. L.M. Antunes, “Multilevel inverter topologies for stand-alone PV systems,” IEEE Trans. Ind. Electron., vol. 55, no. 7, pp. 2703–2712, Jul. 2008.

[3] W. Yu, J. S. Lai, H. Qian, and C. Hutchens, “High-efficiency MOSFET inverter with H6-type configuration for photovoltaic nonisolated, acmodule applications,” IEEE Trans. Power Electron., vol. 26, no. 4, pp. 1253–1260, Apr. 2011.

[4] R. A. Ahmed, S. Mekhilef, and W. P. Hew, “New multilevel inverter topology with minimum number of switches,” in Proc. IEEE Region 10 Conf. (TENCON), 2010, pp. 1862–1867.

[5] M. R. Banaei and E. Salary, “New multilevel inverter with reduction of switches and gate driver,” in Proc. IEEE 18th Iran. Conf. Elect. Eng. (IECC), 2010, pp. 784–789.

Enhancement of Power Quality in Distribution System using D-Statcom



STATCOM (static synchronous compensator) as a shunt-link flexible AC transmission system(FACTS) controller has shown extensive feasibility in terms of cost-effectiveness in a wide range of problem solving abilities from transmission to distribution levels. Advances in power electronic technologies such as Voltage Source Converter (VSC) improves the reliability and functionality of power electronic based controllers hence resulting in increased applications of STATCOM. In this paper, design and implementation of a Distribution type, Voltage Source Converter (VSC) based static synchronous compensator (DSTATCOM) has been carried out. It presents the enhancement of power quality problems, such as voltage sag and swell using Distribution Static Compensator (D-STATCOM) in distribution system. The model is based on Sinusoidal Pulse Width Modulation (SPWM) technique. The control of the Voltage Source Converter (VSC) is done with the help of SPWM.

The main focus of this paper is to compensate voltage sag and swell in a distribution system. To solve this problem custom power devices are used such as Fixed Compensators (FC, FR), Synchronous Condenser, SVC, SSSC, STATCOM etc. Among these devices Distribution STATCOM (DSTATCOM) is the most efficient and effective modern custom power device used in power distribution networks. DSTATCOM injects a current into the system to mitigate the voltage sag and swell. The work had been carried out in MATLAB environment using Simulink and SIM power system tool boxes. The proposed D-STATCOM model is very effective to enhance the power quality of an isolated distribution system feeding power to crucial equipment in remote areas. The simulations were performed and results were found to be satisfactory using MATLAB/SIMULINK.


  1. Statcom
  2. Facts Controllers
  3. D-Statcom
  4. Voltage Source Converter
  5. Total Harmonic Distortions



Fig.1 Schematic diagram of D-STATCOM



Fig.2 Three Phase to Ground -Voltage at Load Point is 0.6600 p.u

Fig.3 Double Line to Ground- Voltage at Load Point is 0.7070 p.u

Fig.4 Line to Line- Voltage at Load Point is 0.7585

Fig.5 Single Line to Ground- Voltage at Load Point is 0.8257

Fig.6 The waveforms shows THD (41.31%) results of fixed load and variable inductive load.


Fig.7 The wave forms shows THD (21.28%) results of fixed load and variable capacitive load

Fig.8 Three Phase to Ground-Voltage at Load Point is 0.9367 p.u

Fig.9 Double Line to Ground- Voltage at Load Point is0.9800 p.u

Fig.10 Line to Line- Voltage at Load Point is 1.068

Fig.11 Single Line to Ground – Voltage at Load Point is 0.9837

Fig.12 The waveform for pure inductive,capacitive loads with statcom

Fig.13 The waveform for without filter THD results 41.31%

Fig.14 The above waveform for with filter THD results 1.11%



The simulation results show that the voltage sags can be mitigate by inserting D-STATCOM to the distribution system. By adding LCL Passive filter to D-STATCOM, the THD reduced. The power factors also increase close to unity. Thus, it can be concluded that by adding DSTATCOM with LCL filter the power quality is improved.


[1] A.E. Hammad, Comparing the Voltage source capability of Present and future Var Compensation Techniques in Transmission System, IEEE Trans, on Power Delivery. Volume 1. No.1 Jan 1995.

[2] G.Yalienkaya, M.H.J Bollen, P.A. Crossley, “Characterization of Voltage Sags in Industrial Distribution System”, IEEE transactions on industry applications, volume 34, No. 4, July/August, PP.682-688, 1999

[3] Haque, M.H., “Compensation of Distribution Systems Voltage sags by DVR and D STATCOM”, Power Tech Proceedings, 2001 IEEE Porto, Volume 1, PP.10-13, September 2001.

[4] Anaya-Lara O, Acha E., “Modeling and Analysis Of Custom Power Systems by PSCAD/EMTDC”, IEEE Transactions on Power Delivery, Volume 17, Issue: 2002, Pages: 266 272.

[5] Bollen, M.H.J.,”Voltage sags in Three Phase Systems”, Power Engineering Review, IEEE, Volume 21, Issue: 9, September 2001, PP: 11-

A Voltage Regulator for Power Quality Improvement in Low-Voltage Distribution Grids


This paper presents a voltage-controlled DSTATCOM-based voltage regulator for low voltage distribution grids. The voltage regulator is designed to temporarily meet the grid code, postponing unplanned investments while a definitive solution could be planned to solve regulation issues. The power stage is composed of a three-phase four-wire Voltage Source Inverter (VSI) and a second order low-pass filter. The control strategy has three output voltage loops with active damping and two dc bus voltage loops. In addition, two loops are included to the proposed control strategy: the concept of Minimum Power Point Tracking (mPPT) and the frequency loop. The mPPT allows the voltage regulator to operate at the Minimum Power Point (mPP), avoiding the circulation of unnecessary reactive compensation. The frequency loop allows the voltage regulator to be independent of the grid voltage information, especially the grid angle, using only the information available at the Point of Common Coupling (PCC). Experimental results show the regulation capacity, the features of the mPPT algorithm for linear and nonlinear loads and the frequency stability.


  2. Frequency compensation
  3. Minimum power point tracker
  4. Power quality
  5.  Static VAR compensators
  6. Voltage control
  7. Voltage regulation



 Fig. 1. Low voltage distribution grid under analysis with the voltage regulator



 Fig. 2. Dc bus voltages during the DSTATCOM initialization


Fig. 3. PCC voltages without compensation for linear loads

Fig. 4. PCC voltages with compensation for linear loads

Fig. 5. Voltage regulator currents for linear loads

Fig. 6. Grid, load and voltage regulator currents for linear loads

Fig. 7. PCC voltages without compensation for nonlinear loads

Fig. 8. PCC voltages with compensation for nonlinear loads

Fig. 9. Voltage regulator currents for nonlinear loads

Fig. 10. Grid, load and voltage regulator currents for nonlinear loads

Fig. 11. PCC rms value with linear loads

Fig. 12. Processed apparent power with linear loads

Fig. 13. Voltage regulator currents with mPPT enabled for linear loads

Fig. 14. PCC rms value with nonlinear loads

Fig. 15. Processed apparent power with nonlinear loads

Fig. 16. Voltage regulator currents with mPPT enabled for nonlinear loads

Fig. 17. Total dc bus voltage, PCC voltage, grid voltage and voltage regulator current waveforms of a-phase with mPPT enabled with grid swell

Fig. 18. (a) Total dc bus voltage, PCC voltage, grid voltage and voltage regulator current waveforms of a-phase and (b) detail of total dc bus voltage performance with mPPT enabled with grid sag


This paper presents a three phase DSTATCOM as a voltage regulator and its control strategy, composed of the conventional loops, output voltage and dc bus regulation loops, including the voltage amplitude and the frequency loops.

Experimental results demonstrate the voltage regulation capability, supplying three balanced voltages at the PCC, even under nonlinear loads.

The proposed amplitude loop was able to reduce the voltage regulator processed apparent power about 51 % with nonlinear load and even more with linear load (80%). The mPPT algorithm tracked the minimum power point within the allowable voltage range when reactive power compensation is not necessary. With grid voltage sag and swell, the amplitude loop meets the grid code. The mPPT can also be implemented in current-controlled DSTATCOMs, achieving similar results.

The frequency loop kept the compensation angle within the analog limits, increasing the autonomy of the voltage regulator, and the dc bus voltage regulated at nominal value, thus minimizing the dc bus voltage steady state error. Simultaneous operation of the mPPT and the frequency loop was verified.

The proposed voltage regulator is a shunt connected solution, which is tied to low voltage distribution grids without any power interruption to the loads, without any grid voltage and impedance information, and provides balanced and low-THD voltages to the customers.


[1] ANEEL National Electric Power Distribution System Procedures – PRODIST, Module 8: Energy Quality. Revision 07, 2014.

[2] M. Mishra, A. Ghosh and A. Joshi, “Operation of a DSTATCOM in voltage control mode,” IEEE Trans. Power Del., vol. 18, no. 1, pp. 258-264, Jan. 2003.

[3] G. Ledwich and A. Ghosh, “A flexible DSTATCOM operating in voltage or current control mode,” IEE Proc.-Gener., Transmiss. Distrib., vol. 149, n. 2, pp. 215-224, Mar. 2002.

[4] T. P. Enderle, G. da Silva, C. Fischer, R. C. Beltrame, L. Schuch, V. F. Montagner and C. Rech, “D-STATCOM applied to single-phase distribution networks: Modeling and control,” in Proc. IEEE Ind. Electron. Soc. Annu. Conf., Oct. 2012, pp. 321 – 326.

[5] C. Kumar and M. Mishra, “Energy conservation and power quality improvement with voltage controlled DSTATCOM,” in Proc. Annu. IEEE India Conf., Dec. 2013 pp. 1-6.


A Power Quality Improved Bridgeless Converter-Based Computer Power Supply



Poor power quality, slow dynamic response, high device stress, harmonic rich, periodically dense, peaky, distorted input current are the major problems that are frequently encountered in conventional switched mode power supplies (SMPSs) used in computers. To mitigate these problems, it is proposed here to use a nonisolated bridgeless buck-boost single-ended primary inductance converter (SEPIC) in discontinuous conduction mode at the front end of an SMPS. The bridgeless SEPIC at the front end provides stiffly regulated output dc voltage even under frequent input voltage and load variations. The output of the front end converter is connected to a half-bridge dc–dc converter for isolation and also for obtaining different dc voltage levels at the load end that are needed in a personal computer. Controlling a single output voltage is able to regulate all the other dc output voltages as well. The design and simulation of the proposed power supply are carried out for obtaining an improved power quality that is verified through the experimental results.


  1. Bridgeless converter
  2. Computer power supply
  3. Input current
  4. Power factor correction (PFC)
  5. Power quality



Fig. 1. Schematic diagram of the PFC converter based SMPS.



 Fig. 2. (a) Performance of the computer power supply at rated condition. (b) Input current and its harmonic spectrum at full load condition. (c)Waveform across various components of the bridgeless converter.

Fig. 3. (a) Performance of the computer power supply at light load condition. (b) Input current and its harmonic spectrum at light load condition.


A bridgeless nonisolated SEPIC based power supply has been proposed here to mitigate the power quality problems prevalent in any conventional computer power supply. The proposed power supply is able to operate satisfactorily under wide variations in input voltages and loads. The design and simulation of the proposed power supply are initially carried to demonstrate its improved performance. Further, a laboratory prototype is built and experiments are conducted on this prototype. Test results obtained are found to be in line with the simulated performance. They corroborate the fact that the power quality problems at the front end are mitigated and hence, the proposed circuit can be a recommended solution for computers and other similar appliances.


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