Real Time Control of an Active Power Filter under Distorted Voltage Condition

ABSTRACT:

This paper, presents three phase shunt active filter under distorted voltage condition, the active power filter control is based on the use of self-tuning filter (STF) for reference current generation and on space vector PWM for generation of pulses. The dc capacitor voltage is controlled by a classical PI controller. The diode rectifier feed RL load is taken as a nonlinear load. The self-tuning filter allows extracting directly the voltage and current fundamental components in the axis without phase locked loop (PLL) under distorted voltage condition. The experiment analysis is made based on working under distorted voltage condition, and the total harmonic distortion of source current after compensation .Self tuning filter based extraction technique is good under distorted voltage conditions. The total harmonic distortion (THD) of source current is fully reduced. The effectiveness of the method is theoretically studied and verified by experimentation.

KEYWORDS:

1.      active power filters,

2.      dSPACE1104,

3.      real time

4.      STF

5.      SVM

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Figure 1. Active Power Filter

 EXPECTED SIMULATION RESULTS:

Figure 2. The source voltage

Figure 3. The load current

Figure 4. Source current

Figure 5. Filter current and its reference

Figure 6. The DC voltage

Figure 7. Load current's harmonic spectrum

Figure 8. Source current's harmonic spectrum

CONCLUSION:

A modified pq theory control technique applied to a three-phase Shunt Power Filter is proposed. The appropriate control strategy for removing harmonics caused by non-linear loads is developed. The main advantage of the proposed method is its simplicity (no PLL circuit needed) and its efficiency in non-ideal voltage condition. The use of SVPWM method allows to the inverter to fellow its reference accurately which increase the performance of the active filter. The experiment results show the efficiency of the proposed method in terms of harmonic reduction as shown in Figure12, the THD obtained by the new control technique has been drastically reduced.

REFERENCES:

[1] N. Mariun, A. Alam, S. Mahmod, and H. Hizam, “Review of control strategies for power quality conditioners”, in Power and Energy Conference, 2004. PECon 2004. Proceedings. National, 2004, pp. 109– 115.

[2] G. W. Chang and C. M. Yeh, “Optimisation-based strategy for shunt active power filter control under non-ideal supply voltages”, IEE Proceedings - Electric Power Applications, vol. 152, no. 2, p. 182, 2005.

[3] S. George and V. Agarwal, “A DSP Based Optimal Algorithm for Shunt Active Filter Under Nonsinusoidal Supply and Unbalanced Load Conditions”, Power Electronics, IEEE Transactions on, vol. 22, no. 2, pp. 593 –601, Mar. 2007.

[4] M. I. M. Montero, E. R. Cadaval, and F. B. Gonzalez, “Comparison of Control Strategies for Shunt Active Power Filters in Three-Phase Four-Wire Systems”, Power Electronics, IEEE Transactions on, vol. 22, no. 1, pp. 229 –236, Jan. 2007.

[5] M. Abdusalam, P. Poure, and S. Saadate, “Hardware implementation of a three-phase active filter system with harmonic isolation based on self-tuning-filter”, in IEEE Power Electronics Specialists  Conference, 2008. PESC 2008, 2008, pp. 2875–2881.,