Neuro-fuzzy current controller for three-level cascade inverter based D-STATCOM


Distribution STATCOM (D-STATCOM) is a custom power device connected in parallel to power system. In this paper, Neuro-Fuzzy Controller (NFC) which has robust structure is proposed for control of D-STATCOM’s dq-axis currents. Designed NFC is first order Mamdani type NFC structure and has two inputs, one output and six layers. DSTATCOM is based on three-level cascaded inverter and this inverter is controlled with Sinusoidal Pulse Width Modulation (SPWM) technique. dSPACE’s DS1103 control card is used for real-time implementation of D-STATCOM’s control algorithm. The performance of D-STATCOM using NFC is evaluated by changing of reference reactive current (iqref) as on-line. Under this condition, some experimental results obtained from experimental setup are given.


  2. Neuro-Fuzzy Current Controller
  3. SPWM
  4. Three-Level Cascade Inverter



Fig.1. Three-level cascaded inverter based D-STATCOM



Fig.2. Changing of dc link voltages

 Fig.3. iqref tracking performance of iq

Fig.4. Phase-a current and voltage waveforms of D-STATCOM


Fig.5. Changing of modulation index

Fig.6. Changing of phase angle


In this paper, NFC is developed to synthesize the current control loop of D-STATCOM. NFC which is a combination of ANN and FLC gives the D-STATCOM a good dynamic response and excellent tracking ability in changing of iqref. Experimental results show that Neuro-Fuzzy current controlled D-STATCOM can provide the desired reactive power exact and fast within own rated power limits even in the worst operating condition.


[1] S. Mohagheghi, “Adaptive Critic Designs Based Neuro-Controllers for Local and Wide Area Control of a Multimachine Power System with A Static Compensator,” Phd. Thesis, Georgia Institute of Technology, 2006.

[2] C. Schauder, H. Mehta, “Vector Analysis and Control of Advanced Static VAr Compensators,” Generation, Transmission and Distribution, IEE Proceedings C, vol.140, pp. 299-360, 1993.

[3] V. Blasko, V. Kaura, “A New Mathematical Model and Control of A Three-Phase AC-DC Voltage Source Converter,” IEEE Transactions on Power Electronics, vol.12, pp. 116-123, 1997.

[4] P. W. Lehn, M. R. Iravani, “Experimental Evaluation of STATCOM Closed Loop, IEEE Transactions on Power Delivery,” vol.13, pp. 1378-1384, 1998.

[5] P. Rao, M. L. Crow, Z. Yang, “STATCOM Control for Power System Voltage Control Applications,” IEEE Transactions on Power Delivery, vol.15, pp.1311-1317, 2000.

Simulation Analysis of SVPWM Inverter Fed Induction Motor Drives


In this paper represent the simulation analysis ofspace vector pulse width modulated(SVPWM) inverter fedInduction motor drives. The main objective of this paper isanalysis of Induction motor with SVPWM fed inverter and harmonic analysis of voltages & current. for control of IMnumber of Pulse width modulation (PWM) schemes are used tofor variable voltage and frequency supply. The most commonlyused PWM schemes for three-phase voltage source inverters(VSI) are sinusoidal PWM (SPWM) and space vector PWM(SVPWM). There is an increasing trend of using space vectorPWM (SVPWM) because of it reduces harmonic content involtage, Increase fundamental output voltage by 15% & smoothcontrol of IM. So, here present Modeling & Simulation ofSVPWM inverter fed Induction motor drive inMATLAB/SIMULINK software. The results of Total HarmonicDistortion (THD), Fast Fourier Transform (FFT) of current areobtained in MATLAB/Simulink software.


  1. Inverter
  2. VSI
  3. SPWM
  4. SVPWM
  5. IM drive



  Figure 1.Simulation Block Diag. of SVPWM Three level inverter with IM load



Figure 2 Inverter Line voltage

Figure 3 Inverter Line currents

Figure 4 Stator Current

Figure 5 Rotor Current

Figure 6 Mechanical Speed

Figure 7 Torque

Figure 8 Harmonic (FFT) Analysis of Line current


The SVPWM Inverter fed induction motor driveModeling & then simulation is done in MATLAB/SIMULINK 12. From simulation results of THD & FFT analysis concluded that SVPWM technique is better overall PWM techniques which gives less THD in Inverter current 4.89%., which under the permissible limit.


[1] A. R. Bakhshai H. R. Saligheh Rad G. Joos, space vectormodulation based on classification method in three-phasemulti-level voltage source inverters, IEEE 2001

[2] Bimal K Bose, modern power electronics and ac drives © 2002Prentice hall ptr.

[3] Dorin O. Neacsu, space vector modulation –An introductiontutorial at IECON2001 IEEE 2001

[4] Fei Wang, Senior Member, “Sine-Triangle versus Space-VectorModulation for Three-Level PWM Voltage-Source Inverters”,IEEE transactions on industry applications, vol. 38, no. 2,March/April 2002. The 27th Annual Conference of the IEEEIndustrial Electronics Society

[5] F. Wang, Senior, Sine-Triangle vs. space vector modulation forthree-level voltage source inverters ,IEEE 2000


Solar Grid-Tied Inverter, with Battery Back-up, for Efficient Solar Energy Harvesting


Solar Grid-Tied Inverter system is an electricity generating system that is connected to the utility grid. This paper discusses the design of a Grid-Tied Inverter (GTI). The first stage is Maximum Power Point Tracking (MPPT) which is implemented using perturb and observe algorithm. Then push pull converter is used to convert DC output from MPPT stage to 330V dc. This DC voltage is then converted into AC voltage using full-wave inverter topology employing unipolar SPWM technique. Then synchronization is achieved between grid and photovoltaic system. Finally, power flow control mechanism controls the power flow from GTI system to the grid and the house load.


  1. Grid-tied inverter
  2. SPWM
  3. Power flow
  4. MPPT




Figure 1. Cuk converter.


Figure 2. Full wave inverter topology .



Figure 3. Inverter output before filter


Figure 4. Inverter output after filter.


Figure 5. Simulink circuit to demonstrate power flow.


Figure 6. GTI output power.


Figure 7. Grid output power.


Figure 8. Power through inductor.


Figure 9. GTI output power.


Figure 10. Grid output power.


Figure 11. Power through inductor.


[1] Power Electronics: Circuits, Devices and Applications, 3/E by M. H. Rashid, Prentice Hall, 2004J. Clerk Maxwell, A Treatise on Electricity and Magnetism, 3rd ed., vol. 2. Oxford: Clarendon, 1892, pp.68–73.

[2] Electric Machinery Fundamentals by Stephen J. Chapman, 4th Edition, McGraw-Hill, 2005K. Elissa, “Title of paper if known,” unpublished.

[3] M. A. Salam, Fundamentals of Power Systems, Alpha Science Oxford, UK International Ltd., 2009.

[4] T. Kwang and S. Masri, “Grid Tie Photovoltaic Inverter for Residential Application,” Modern Applied Science, vol. 5, No. 4, Aug. 2011, pp. 3-4, doi:10.5539/mas.v5n4p200