Cascaded Control of Multilevel Converter based STATCOM for Power System Compensation of Load Variation

ABSTRACT:

The static synchronous compensator (STATCOM) is used in power system network for improving the voltage of a particular bus and compensate the reactive power.It can be connected to particular bus as compensating device to improve the voltage profile and reactive power compensation. In this paper, a multi function controller is proposed and discussed. The control concept is based on a linearization of the d-q components with cascaded controller methods. The fundamental parameters are controlled with using of proportional and integral controller. In closed loop method seven level cascaded multilevel converter (CMC) is proposed to ensure the stable operation for damping of power system oscillations and load variation.

KEYWORDS:

  1. FACTS
  2. PWM
  3. CMC
  4. STATCOM

 SOFTWARE: MATLAB/SIMULINK

TEST SYSTEM:

 Figure 1.STATCOM network connection.

 EXPECTED SIMULATION RESULTS:

Figure 2. Load terminal dq0 Currents with Load variation

Figure 3. Source terminal dq0 Currents with Load variation.

Figure 4. Iqref output for load rejection.

Figure 5. Source Voltage for load rejection with AGC.

Figure 6. THD of output Voltage of Cascaded Multilevel converter.

Figure 7. THD of output Current of Cascaded Multilevel Converter

Figure 8.Source Active and Reactive power.

Figure 9. Power factor in Load and Source Bus

Figure 10.Three phase Supply Voltage of multilevel converter.

 CONCLUSION:

The cascaded controller is designed for seven level CMC based STATCOM. This control scheme regulates the capacitor voltage of the STATCOM and maintain rated supply voltage for any load variation with in the rated value. It has been shown that the CMC is able to reduce the THD values of output voltage and current effectively. The CMC based STATCOM ensures that compensate the reactive power and reduce the harmonics in output of STATCOM.

 REFERENCES:

[1] N. Hingorani and L. Gyugyi, 2000, “Understanding FACTS: Concepts and Technology Flexible AC Transmission Systems”, New York: IEEE Press.

[2] P. Lehn and M. Iravani, Oct.1998, “Experimental evaluation of STATCOM closed loop dynamics”, IEEE Trans. Power Delivery, vol.13, pp.1378-1384.

[3] Mahesh K.Mishra and Arindam Ghosh, Jan 2003, ”Operation of a D-STATCOM in Voltage Control Mode”, IEEE Trans. Power Delivery, vol.18, pp.258-264.

[4] Arindam Ghosh, Avinash Joshi, Jan 2000, ”A New Approach to Load Balancing and Power Factor Correction in Power Distribution System”, IEEE Trans. Power Delivery, vol.15, No.1, pp. 417-422.

[5] Arindam Ghosh, Gerard Ledwich, Oct 2003,”Load Compensating DSTATCOM in Weak AC Systems”, IEEE Trans. Power Delivery, vol.18, No.4, pp.1302-1309.

 

Design and Simulation of Single Phase Shunt Active Power Filter using MATLAB

ABSTRACT:

Power Quality issues are becoming a major concern of today’s power system engineers. Harmonics play significant roll in deteriorating power quality, called harmonic distortion. Harmonic distortion in electric distribution system is increasingly growing due to the widespread use of nonlinear loads. Large considerations of these loads have the potential to raise harmonic voltage and currents in an electrical distribution system to unacceptable high levels that can adversely affect the system. IEEE standards have defined limits for harmonic voltages and harmonic currents. Active power filters have been considered a potential candidate to bring these harmonic distortions within the IEEE limits. This paper deals with an active power filter (APF) based on simple control. A voltage source inverter with pulse width modulation (PWM) is employed to form the APF. A diode rectifier feeding capacitive-resistive load is considered as nonlinear load on ac mains for the elimination of harmonics by the proposed APF. MATLAB model of the scheme is simulated and obtained results are studied.

KEYWORDS:

  1. Power Quality
  2. THD
  3. Non-linear Load
  4. PWM

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Figure 1 Principle of Shunt connected SPAPF

EXPECTED SIMULATION RESULTS:

Figure 2. Load Current without SPAPF

Figure 3. Load Current Harmonic Spectrum without SPAPF

Figure 4. Load Voltage without SPAPF

Figure 5. Load Current Harmonic Spectrum without SPAPF

Figure 6. Load Current with SPAPF

Figure 7. Load Current Harmonic Spectrum with SPAPF

Figure 8. Load Voltage without SPAPF

Figure 9. Load Voltage Harmonic Spectrum with SPAPF

 CONCLUSION:

A simple control scheme of the single phase active power filter is proposed which requires sensing of one current and two voltages only. The APF results in sinusoidal unity power factor supply current. It is concluded that the reduced value of dc bus capacitor is able to give quite satisfactory operation of the APF system. The voltage controller gives fast response. The proposed APF is able to reduce THD of supply current and supply voltage below prescribed permitted limits specified by IEEE 519.

REFERENCES:

[1] D. C. Bhonsle, Dr. R. B. Kelkar and N. K. Zaveri, “Power Quality Issues-In Distribution System”, IE(I) 23rd National Convention of Electrical Engineers, Pune, November 2007 Proceedings, pp. 108-111.

[2] K. C. Umeh, A. Mohamed, R. Mohmed, “ Comparing The Harmonic Characteristics of Typical Single Phase Nonlinear Loads”, National Power Energy Conference (PECon) 2003 Proceedings, Bangi, Malaysia, pp. 383-387.

[3] Mohamed S. A. Dahidah, N. Mariun, S. Mahmod and N. Khan, “Single Phase Active Power Filter for Harmonic Mitigation in Distribution Power Lines”, National Power and Energy Conference (PECon) 2003 Proceedings, Bangi, Malaysia, pp. 359-362.

[4] Dalila Mat Said Ahmed, Abdullah asuhaimi, Mohd Zin, “Power Supply Quality Improvement: Harmonic Measurement and Simulation,” National Power and Energy Conference (PECon), 2003 Proceedings, Bangi, Malaysia, pp. 352-358.

[5] C. Gopalkrishnan, K Udaykumar, T. A. Raghvendiran, “Survey of Harmonic Distortion for Power Quality Measurement and Application of Standard including Simulation,” 2001, Anna University, India.

 

Design and Simulation of Single Phase Shunt Active Power Filter using MATLAB

ABSTRACT:

Power Quality issues are becoming a major concern of today’s power system engineers. Harmonics play significant roll in deteriorating power quality, called harmonic distortion. Harmonic distortion in electric distribution system is increasingly growing due to the widespread use of nonlinear loads. Large considerations of these loads have the potential to raise harmonic voltage and currents in an electrical distribution system to unacceptable high levels that can adversely affect the system. IEEE standards have defined limits for harmonic voltages and harmonic currents. Active power filters have been considered a potential candidate to bring these harmonic distortions within the IEEE limits. This paper deals with an active power filter (APF) based on simple control. A voltage source inverter with pulse width modulation (PWM) is employed to form the APF. A diode rectifier feeding capacitive-resistive load is considered as nonlinear load on ac mains for the elimination of harmonics by the proposed APF. MATLAB model of the scheme is simulated and obtained results are studied.

KEYWORDS:
1. Power Quality
2. THD
3. Non-linear Load
4. PWM

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Figure 1 Principle of Shunt connected SPAPF

CIRCUIT DIAGRAM:

Figure 2. Basic Circuit of Single Phase APF

EXPECTED SIMULATION RESULTS:

Figure 3. Load Current without SPAPF

Figure 4. Load Current Harmonic Spectrum without SPAPF


Figure 5. Load Voltage without SPAPF

Figure 6. Load Current Harmonic Spectrum without SPAPF

Figure 7. Load Current with SPAPF

Figure 8. Load Current Harmonic Spectrum with SPAPF

Figure 9. Load Voltage without SPAPF

Figure 10. Load Voltage Harmonic Spectrum with SPAPF

CONCLUSION:
A simple control scheme of the single phase active power filter is proposed which requires sensing of one current and two voltages only. The APF results in sinusoidal unity power factor supply current. It is concluded that the reduced value of dc bus capacitor is able to give quite satisfactory operation of the APF system. The voltage controller gives fast response. The proposed APF is able to reduce THD of supply current and supply voltage below prescribed permitted limits specified by IEEE 519.
REFERENCES:

[1] D. C. Bhonsle, Dr. R. B. Kelkar and N. K. Zaveri, “Power Quality Issues-In Distribution System”, IE(I) 23rd National Convention of Electrical Engineers, Pune, November 2007 Proceedings, pp. 108-111.
[2] K. C. Umeh, A. Mohamed, R. Mohmed, “ Comparing The Harmonic Characteristics of Typical Single Phase Nonlinear Loads”, National Power Energy Conference (PECon) 2003 Proceedings, Bangi, Malaysia, pp. 383-387.
[3] Mohamed S. A. Dahidah, N. Mariun, S. Mahmod and N. Khan, “Single Phase Active Power Filter for Harmonic Mitigation in Distribution Power Lines”, National Power and Energy Conference (PECon) 2003 Proceedings, Bangi, Malaysia, pp. 359-362.
[4] Dalila Mat Said Ahmed, Abdullah asuhaimi, Mohd Zin, “Power Supply Quality Improvement: Harmonic Measurement and Simulation,” National Power and Energy Conference (PECon), 2003 Proceedings, Bangi, Malaysia, pp. 352-358.
[5] C. Gopalkrishnan, K Udaykumar, T. A. Raghvendiran, “Survey of Harmonic Distortion for Power Quality Measurement and Application of Standard including Simulation,” 2001, Anna University, India.

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.

 

Offshore Wind Farms – VSC-based HVDC Connection

 

ABSTRACT:

Due to significantly higher and more constant wind speeds and the shortage of suitable sites for wind turbines on the land, offshore wind farms are becoming very attractive. The connection of the large offshore wind farms is possible with HVAC, classical HVDC and Voltage Source Converter (VSC based) HVDC technology. In this paper their main features will be given. From the economical and technical viewpoint, the type of connection depends on the size of the wind farm and on the distance to the connection point of the system.

As very promising technology, especially from the technical viewpoint, the focus of this paper will be put on the VSC-based HVDC technology. Its main technical features as well as its model will be detailed. At the end, obtained simulation results for different faults and disturbances for one offshore wind farm connected with VSC-based HVDC technology will be presented.

KEYWORDS:

  1. HVDC
  2. IGBT
  3. Offshore wind farm connection
  4. PWM
  5. Requirements
  6. Stability
  7. VSC

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

 

Fig. 1. Principal scheme of VCS-based HVDC connection

EXPECTED SIMULATION RESULTS:

 

 Fig. 2. Active and reactive power at the connection point during reactive power control

Fig. 3. Active and reactive power at the wind farm side during reactive power control

Fig. 4. Active power, reactive power and voltage at system and wind farm side in case of single phase short circuit near to the connection point – 100ms

Fig. 5. Active power, reactive power and voltage at system and wind farm side in case of single phase short circuit at the wind farm side – 100ms

 CONCLUSION:

The connection of an offshore wind farm depends primarily on the amount of power that has to be transmitted and the distance to the connection point.

Primarily due to comparatively small size and short distance to the connection point as well as due to its lower costs and experience, all actual offshore wind farms and those planned to be installed are still using/plan to use HVAC connection.

The advantages of using a HVDC solution are more significant with increase of the distance and power.

The VSC-based HVDC technology is due to its technical advantages like: active and, especially, reactive power control (voltage control), isolated operation, no need for an active commutation voltage etc. very good solution for an offshore wind farm connection. Performed simulation and their results of simulated faults and disturbances show that the technical requirements can be fulfilled.

REFERENCES:

[1] European Wind Energy Association. (2004). Wind Energy – The Facts. [Online]. Available: http://www.ewea.org

[2] Global Wind Energy Council. (2004). [Online]. Available: http://www.gwec.net

[3] F.W. Koch, I. Erlich, F. Shewarega, and U. Bachmann, “Dynamic interaction of large offshore wind farms with the electric power system”, in Proc. 2003 IEEE Power Tech Conf., Bologna, Italy, vol. 3, pp. 632-638.

[4] J.G. Slootweg and W.L. Kling, “Is the Answer Blowing in the Wind?”, IEEE Power and Energy Magazine, vol. 1, pp. 26-33, Nov./Dec. 2003.

[5] Wind Energy Study 2004. [Online]. Available: http://www.ewea.org

Diode Clamped Three Level Inverter Using Sinusoidal PWM

 

ABSTRACT:

An inverter is a circuit which converts dc power into ac power at desired output voltage and frequency. The ac output voltage can be fixed at a fixed or variable frequency. This conversion can be achieved by controlled turn ON & turn OFF or by forced commutated thyristors depending on applications. The output voltage waveform of a practical inverter is non sinusoidal but for high power applications low distorted sinusoidal waveforms are required. The filtering of harmonics is not feasible when the output voltage frequency varies over a wide range. There is need for alternatives. Three level Neutral Point Clamped inverter is a step towards it.

KEYWORDS:

  1. Harmonics
  2. Inverter
  3. THD
  4. PWM

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Figure1.Diode clamped three level inverter

EXPECTED SIMULATION RESULTS:

 

 Figure2. Upper triangular pulse width modulation

Figure3. lower triangular pulse width modulation

Figure4. three level voltage waveform

Figure5.Matlab model of three level inverter feeding induction motor

 Figure 6. stator waveform of three level inverter

 CONCLUSION:

In normal inverters odd harmonics are present which causes distortion of the output waveform. By using the “THREE LEVEL DIODECLAMPED INVERTER” we can eliminate some number of harmonics hence increasing the efficiency of the inverter.

 REFERENCES:

[1] A.Mwinyiwiwa, Zbigneiw Wolanski, ‘Microprocessor Implemented SPWM for Multiconverters with Phase-Shifted Triangle Carriers’ IEEE Trans. On Ind. Appl., Vol. 34, no. 3, pp 1542-1549, 1998.

[2] J. Rodriguez, J.S. Lai, F. Z. Peng, ’ Multilevel Inverters: A Survey of Topologies, Controls and Applications’, IEEE Trans. On Ind. Electronics, VOL. 49, NO. 4, pp. 724-738, AUGUST 2002

[3] D. Soto, T. C. Green, ‘A Comparison of High Power Converter Topologies for the Implementation of FACTS Controller’, IEEE Trans. On Ind. Electronics, VOL. 49, NO. 5, pp. 1072-1080, OCTOBER 2002.

[4] Muhammad H. Rashid, Power Electronics: Circuits, Devices and Applications, Third edition, Prentice Hall of India, New Delhi, 2004.

[5] Dr. P. S. Bimbhra, Power Electronics, Khanna Publishers, Third Edition, Hindustan Offset Press, New Delhi-28, 2004.