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.

A Novel Power Factor Correction Technique/or a Boost Converter

 

ABSTRACT:

The paper evolves a mechanism for improving the input power factor of an AC-DC-DC conversion system. It involves the process of shaping the input current wave to phase align with the input supply through a process of error compensation. The methodology includes cohesive formulation to arrive at nearly unity power factor and enjoy the etiquettes of output voltage regulation. The theory assuages to subscribe the benefits for the entire range of operating loads. It eliminates the use of passive components and fortifies the principles of pulse width modulation (PWM) for realizing the change in duty cycle. The MA TLAB based simulation results arbitrate the viability of the proposed approach and exhibit its suitability for use in real world applications.

 KEYWORDS:

  1. Ac-dc converter
  2. Power factor
  3. THD
  4. Voltage regulation

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

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Figure 1. Power Factor Correction Control of Boost Converter

 EXPECTED SIMULATION RESULTS:

 image002

 Figure 2. Steady State Input AC Voltage and Input AC Current Waveform

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Figure 3. Steady State Rectified DC Voltage and Rectified DC Current Waveform

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Figure 4. Steady State Regulated DC Output Voltage and Regulated DC Output Current Waveform

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Figure 5. Power Factor Measurement of the Proposed Power Factor Correction Boost Converter

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Figure 6. FFT Spectrum of the AC input current of Proposed Power Factor Correction Boost Converter

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Figure 7. Transient response of Input AC Voltage and Input AC Current Waveform

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Figure 8. Transient Response of Rectified DC Voltage and Rectified DC Current Waveform

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Figure 9. Transient Response of Regulated DC Output Voltage and Regulated DC Output Current Waveform

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Figure 10. Power Factor Measurement of the Proposed Power Factor Correction Boost Converter at transient condition

CONCLUSION:

A single stage power factor correction strategy has been proposed for full bridge diode rectifier fed boost converter to support a 400W, lA DC load. The suitability of boost converter for power factor correction has been illustrated by the elimination of input capacitor filter and low output ripple factor. The formulated control design has been effectively orchestrated to correct the power factor in addition providing good voltage regulation. The transient performance has been portrayed to up-heave the strength of the control structure with an adequate output regulation and effective harmonic elimination. The control plan has been nurtured to standardize the THD level of the system that prevents the adverse effects of harmonics being injected in the grid. The exclusion of additional passive components and interleaving configuration has been fostered to reduce the size thus making it more adaptive to low cost compact electronic applications with high standards .

 REFERENCES:

[1] M. Milanovic, F . Mihalic, K. Jezernik and U. Milutinovic,” Single phase unity power factor correction circuits with coupled inductance,” Power Electronics Specialists Conference, 1992, vol.2, pp. l077-1082.

[2] M. Orabi and T Ninomiya, “Novel nonlinear representation for two stage power-factor-correction converter instability,” IEEE International Symposium on Industrial Electronics, 2003, voU, pp- 270-274.

[3] Yu Hung, Dan Chen, Chun-Shih Huang and Fu-Sheng Tsai, “Pulse-skipping power factor correction control schemes for ACIDC power converters,” Fourth International Conference on Power Engineering, Energy and Electrical Drives (POWERENG), 2013, pp-I087-1092.

[4] Lu, D.D. -C, H.H.-C. lu, V. Pjevalica, “A Single-Stage AC/DC Converter With High Power Factor, Regulated Bus Voltage, and Output Voltage,” Power Electronics, IEEE Transactions on, vo1.23, issue. I, pp. 218-228, Jan. 2008.

[5] M. Narimani and G. Moschopoulos, “A New Single-Phase SingleStage Three-Level Power Factor Correction AC-DC Converter,” Power Electronics, IEEE Transactions on , vol.27, issue.6, pp. 2888- 2899, June. 2012.

Performance Improvement of Single-Phase Grid–Connected PWM Inverter Using PI with Hysteresis Current Controller

 

ABSTRACT:

Now a day’s distributed generation (DG) system uses current regulated PWM voltage-source inverters (VSI) for synchronizing the utility grid with DG source in order to meet the following objectives: 1) To ensure grid stability 2) active and reactive power control through voltage and frequency control 3) power quality improvement (i.e. harmonic elimination) etc. In this paper the comparative study between hysteresis and proportional integral (PI) with hysteresis current controller is presented for 1-Φ grid connected inverter system. The main advantage of hysteresis+PI current controller is low total harmonic distortion (THD) at the point of common coupling (PCC) at a higher band width of the hysteresis band. The studied system is modeled and simulated in the MATLAB Simulink environment.

KEYWORDS:

  1. Hysteresis current controller
  2. PI controller
  3. Point of common coupling (PCC)
  4. DG
  5. Utility grid
  6. THD

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 image001

Fig.1. Block diagram for hysteresis current control of single-phase grid connected VSI

EXPECTED SIMULATION RESULTS:

 image002

 Fig.2. Simulation result of the hysteresis current controller for fixed band (a) grid voltage (Vg) and grid current (Io) (b) reference current, actual current and current error(c) switching frequency

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Fig.3. Simulation result of the hysteresis+PI current controller for fixed band (a) grid voltage (Vg) and grid current (Io) (b) reference current, actual current and current error(c) switching frequency

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Fig.4. Simulation result of hysteresis current controller for change in band (a) grid current (b) switching frequency(c) current error

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Fig.5. Simulation result of hysteresis+PI current controller for change in band (a) grid current (b) switching frequency(c) current error

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Fig.6. THD of grid current for hysteresis current controller (a) HB=1(b)HB=3(c)HB=5

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Fig.7. THD of grid current for hysteresis+PI current controller (a) HB=1(b) HB=3(c) HB=5

CONCLUSION:

From the study we observed that, hysteresis+PI current controller can enable to reduce switching frequency even if the band width increased without any significant increase in the current error. Hence it provides considerably less THD at higher band width as compared to conventional hysteresis current controller.

REFERENCES:

[1] Blaabjerg, F.; Teodorescu, R.; Liserre, M.; Timbus, A.V., “Overview of Control and Grid Synchronization for Distributed Power Generation Systems” IEEE Transactions on Industrial Electronics,Vol.:53 , Issue:5, Page(s): 1398 – 1409, 2006

[2] F.Blaabjerg, Zhe Chen, and S.B. Kjaer. “Power Electronics as Efficient Interface in Dispersed Power Generation Systems”, IEEE Transactions on Power Electronics, 19(5):1184–1194, Sept. 2004.

[3] Ho, C.N.-M.,Cheung, V.S.P.,Chung, H.S.-H.” Constant-Frequency Hysteresis Current Control of Grid-Connected VSI without Bandwidth Control”,IEEE Trans. on Power Electronics, TPEL 2009,Volume: 24, no. 11 ,, Pp:2484 – 2495, 2009

[4] Rahman, M.A.; Radwan, T.S.; Osheiba, A.M.; Lashine, A.E.; “Analysis of Current Controllers for Voltage-Source Inverter” IEEE Trans. On Industrial Electronics, Volume: 44 , no. 4 , Pp. 477 – 485, ,1997

[5] Tekwani, P.N, Kanchan, R.S., Gopakumar, K.; “Current-error spacevector- based hysteresis PWM controller for three-level voltage source inverter fed drives” Proceedings of Electric Power Applications, IEE Volume: 152 , Issue: 5, Pp: 1283 – 1295,2005