Simulation Circuit Analysis of Shunt Active Power Filter

IJSRD - International Journal for Scientific Research & Development| Vol. 3, Issue 11, 2016 | ISSN (online): 2321-0613

Simulation Circuit Analysis of Shunt Active Power Filter Vivek Rajoria1 Sanjeev Gupta2 1 Student 2Assistant Professor 1,2 Department of Electrical Engineering 1,2 Samrat Ashok Technological Institue, Vidisha (M.P) Abstract— Use of power electronic equipment today is increasing the power quality issues. These are becoming a major concern for power distribution system. But IEEE standards have the definite limit for harmonic voltage and current. Shunt Active Power Filter have been considered a one of the best device to control such harmonics dynamically to limit the harmonics within IEEE standard.

This paper deals with an active power filter based on P-Q theory implying Clarke’s transformation to generate a reference current to operate a PWM VSI inverter. The nonlinear loads considered here are both balanced and unbalanced loads. MATLAB model of the scheme is simulated and obtained results are studied.

Key words: APF, PCC, P-Q Theory, Clarkes Transformation I. INTRODUCTION The use solid state controllers are increasing day by day.

These controllers are implying semiconductor devices which are nonlinear because they draw non sinusoidal current from sinusoidal sources. This is also increasing non linearity in the system and also leads to sudden increase in current anywhere in the system. Some of the undesirable effects in system performance are increasing neutral currents in four wire systems, over heating of system components, mechanical oscillations in generator, motors, capacitor and its insulation breakdown due to harmonic resonance, over heating transformers and telephone interferences.

II. ACTIVE POWER FILTER Shunt Active power filters are now seen as a reliable alternative which act dynamically over the conventional passive filters, to compensate harmonics and reactive power requirement of the non-linear loads. The purpose of the active filter is to solve these problems by combining with a much reduced rating of necessary passive component.

Harmonics are eliminated by generating reference current which is calculated by incorporating the Ploss signal. The Ploss signal is calculated by the zero sequence voltage drop across the neutrally clamped capacitor pairs. The voltage drop (Vdc) is compared with a constant voltage (650) to reduce the fluctuations. The compared signal is then given to PI controller to calculate the error signal. Using clarke’s transformation, the line voltages and current per phase are converted from two phase to three phase. This is done to gain the stability. It is because the two phase system is more stable than three phase system. Thus, it is more suitable to do compensation in two phase system as compared to three phases.

By generating reference current, it is compared with the measured current and the compared signals is given to the PWM IGBT inverter as a gate pulse. This signal drives the inverter in accordance with the harmonics need to be compensated. APF works in a closed loop as a controlled current generator which generates a compensation current for the main line. The compensation current generated by the inverter is equal in magnitude but opposite in phase with the harmonics to eliminate them. After adding Ploss signal again the two phase system is converted to three phase.

III. P-Q THEORY The P-Q Theory uses the Clarke transformation, also known as transformation, which consists of a real matrix that linearly maps three phase voltages and currents of the rotator reference frame into the stationary reference frame.

The ιβ0 transformation or the Clarke transformation maps the three-phase instantaneous voltages in the abc phases, Va, Vb, and Vc, into the instantaneous voltages on the ιβ0-axes Vι, Vβ, and V0. It is advantageous to applying the ιβ0 transformation is to separate zerosequence components from the abc-phase components. The ι and β axes contains only positive and negative sequence Components. Since there is no neutral in a three- phase, three-wire system and therefore on zero sequence currents, so Io can be eliminated from the above equations, thus resultant in matrix simplification. If the 3-phase voltages are exactly fair in a four wire system, so no zero sequence voltage is present, therefore Vo can be eliminated. When zero-sequence voltage and current components are present, the complete transformation should be considered.

IV. MATLAB SIMULATION OF SHUNT ACTIVE POWER FILTER 1 1 1 �ι �β = �0

Fig. 1: Basic scheme of APF Using P-Q theory, harmonic and reactive power compensation is done by using clarke’s transformation.

√2 2 √ 3

1 0

√2 −1 2 −√3 2

√2 −1 √2 −√3 2

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Simulation Circuit Analysis of Shunt Active Power Filter (IJSRD/Vol. 3/Issue 11/2016/057)

1

√2 −1 1 2 −√3 0 2 P= VÎą IÎą + Vβ Iβ Q= VÎą Iβ – Vβ IÎą Po= Vo Io

�ι �β = �0

√2

1

2 √ 3

1 √2 −1 √2 −√3 2 (1) (2) (3)

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Fig. 6: Phase C current waveform VI. CONCLUSION In this paper, three phase four wire neutral clamped shunt active power filter is presented with SIMULINK model. By Using P-Q theory instantaneous powers are calculated and a reference current is generated.

This method of eliminating harmonics is useful because it works dynamically in closed loop with respect to changes in loads. The zero sequence power is compensated using a neutral clamed capacitor. Resulting current waveform in the main circuit is achieved sinusoidal. There is a considerable reduction in total harmonic distortion (THD) in all the three phases.

Fig. 2: Simulink model of shunt active power filter VII. FUTURE SCOPE V. SIMULATION RESULTS The result of MATLAB SIMULINK is performed at phase to phase voltage of 220v at 50 Hz where non linear balanced and unbalanced loads R= 30 ohm, L= 30 mH with APF. Fig. 3 shows the current Ia, Ib, Ic after compensation.

Fig. 3: Current ia, ib, ic After Compensation

Fig. 4: Phase A Current Waveform

Interconnected systems are more reliable, because in case of disruption in one part of the system, power can be fed from alternate paths and thus can maintain continuity of the system. However, harmonic distortions introduced by the nonlinear loads will propagate throughout the system. This issue may be solved by installing filters of suitably designed ratings at best possible locations in the interconnected power system.

The integration of renewable energy into the existing power system generates power quality issues such as sudden voltage transients, instability. Adaptive Shunt Hybrid Filters are suggested for improving power quality issues, when generation rapidly changes with wind velocity.

REFERENCES [1] George Adam, Alina G. Stan (Baciu) and Gheorghe LivinĹŁ Department of Electrical Engineering Technical University of IaĹ&#x;i,â€? a matlab-simulink approach to shunt active power filters. doi:10.1699/28.556633 [2] H. Akagi, “New Trends in Active Filters for Power Conditioning,â€? IEEE Transactions on Industry Applications, Vol. 32, No. 6, 1996, pp. 1312-1322. doi:10.1109/28.556633.

[3] N. A. Rahim, et al., “A Single-Phase Active Power Filter for Harmonic Compensation� Vol. 20, No. 68, 1996, pp. 112-128 doi:10.1109/63.558748 [4] Muhammad Jawwad Iqbal, et al, “design and simulation of three phase shunt active power filter using the p-q theory� vol. 2, no. 1, pp. 146–160, 2013.

[5] Mohamed S. A. Dahidah, et. Al., “Single Phase Active Power Filter for Harmonic Mitigation in Distribution Power Lines� doi_10.1109_2Fpecon.2003.1437474

Fig. 5: Phase B Current Waveform

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Simulation Circuit Analysis of Shunt Active Power Filter (IJSRD/Vol. 3/Issue 11/2016/057)

[6] Wenjin Dai, et al., “A Hysteretic Current Controller for Active Power Filter with Constant Frequency” 978-14244-3820-4/09 ©2009 IEEE doi 10.1109%2Fcimsa.2009.5069924 [7] Dalila mat said, et al. “Power Supply Quality Improvement: Harmonic Measurement and Simulation”. doi_10.1109_2Fpecon.2003.1437473 [8] P. S. Bimbhra“Power Electronics” Khanna Publishers 4th edition 2009 [9] P. S. Bimbhra “Generalized Theory of Electrical Machine.

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