• Journal of Power Electronics
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• v.12 no.2
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• pp.357-362
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• 2012

In this paper, a power electronic converter which is composed of two converters - bidirectional AC/DC converter and Series Active Power Filter (SAPF), is discussed. Structural schemas and ways of operation of control systems of converters, which are used to eliminate non sinusoidal parts of the network source voltage, are presented. At the same time, the control used stabilizes the value of the voltage feeding the load. Taking in consideration the combined functions which the device executes, it may be called Unified Voltage Conditioner - UVC.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.2
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• pp.53-58
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• 2006

This paper proposes a small low-cost power quality compensator to be installed at the electricity supply inlet of residential customer. The compensator is composed of a single-phase active power filter with a simple controller using analog electronics, which can correct the power factor and damp out the harmonics. The operation and performance of proposed compensator was verified through simulations with PSCAD/EMTDC and experimental works with hardware prototype. The proposed compensator can offer reduction of power loss and improvement of power quality to the residential customer.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.214-217
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• 2003

The connectorless power supply system on that multi-contact causes confidence when the wiring reconstructed in the rear. As you see above, contact points between sets and indoor space cause inferior function of audio frequency so it needs to be eliminated. This paper explains the structure of connectorless power supply to supply the system with power crossing the air gap in the part of inductively in the connectorless power supply of both magnetic and electrical model. To get maximum output of electrical load, compensating capacitor compensates to show inter-inductance, lequeage-inductance reducing the track-inductance and access the conditions for resonance. At that time it accesses the maximum electric power. The small change of the value of compensating capacitor causes the changes of maximum electric power. Here the power electronics technology is used not only in the industrial machinery but also in the home appliances so the switching power supply is used to actualize the miniaturization, lightweight, and high efficiency. Generally the condenser input methods are widely used in the rectification circuit of switching power supply, but condenser input method generate great quantity of high frequency components because with this method the current flows in the power input filtering condenser only around value of peak of ac input voltage. To solve these problems, installation of power factor improve circuit on the front of filtering capacitence was considered. Several methods were suggested regarding, but the active filter method which makes smalliging and highly power factor possible are the produce main stream. IC for power factor improvement can be utilized by CMOS process proposing low power consumption. When the high power factor is considered seriously in the power factor improvement circuit, active filter method is selected. In the active filter method, the boost converter is used. Regarding this ·the boost converter is needed.

• Journal of Power Electronics
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• v.10 no.5
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• pp.548-554
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• 2010

In this paper, a 1.5 kW Interior Permanent Magnet Synchronous Generator (IPMSG) with a power conditioner for the grid integration of a variable-speed wind turbine is developed. The power-conditioning system consists of a series-type 12-pulse diode rectifier powered by a phase shifting transformer and then cascaded to a PWM voltage source inverter. The PWM inverter is utilized to supply sinusoidal currents to the utility line by controlling the active and reactive current components in the q-d rotating reference frame. While the q-axis active current of the PWM inverter is regulated to follow an optimized active current reference so as to track the maximum power of the wind turbine. The d-axis reactive current can be adjusted to control the reactive power and voltage. In order to track the maximum power of the wind turbine, the optimal active current reference is determined by using a simple MPPT algorithm which requires only three sensors. Moreover, the phase angle of the utility voltage is detected using a simple electronic circuit consisting of both a zero-crossing voltage detecting circuit and a counter circuit employed with a crystal oscillator. At the generator terminals, a passive filter is designed not only to decrease the harmonic voltages and currents observed at the terminals of the IPMSG but also to improve the generator efficiency. The laboratory results indicate that the losses in the IPMSG can be effectively reduced by setting a passive filter at the generator terminals.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.4
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• pp.359-365
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• 2002

Three-phase four-wire electrical distribution systems have been widely employed in manufacturing plants, commercial and residential buildings. Due to the nonlinear loads, the neutral conductor carries excessive harmonic currents resulting in wiring failure of the neutral conductor, overloading of the distribution transformer and a voltage drop between the neutral and the ground. This paper proposes a reduced rating active power filter to suppress neutral current harmonics in three-phase four-wire electrical distribution systems. The proposed system is simple in control and the VA rating of the inverter could be significantly reduced since only the fundamental current due to unbalanced loading flows through the inverter switch. The experimental results on a prototype validate the proposed control approach.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1587-1599
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• 2017

This paper proposes a real-time implementation of an optimal operation of a double stage grid connected wind power system incorporating an active power filter (APF). The system is used to supply the nonlinear loads with harmonics and reactive power compensation. On the generator side, a new adaptive neuro fuzzy inference system (ANFIS) based maximum power point tracking (MPPT) control is proposed to track the maximum wind power point regardless of wind speed fluctuations. Whereas on the grid side, a modified predictive current control (PCC) algorithm is used to control the APF, and allow to ensure both compensating harmonic currents and injecting the generated power into the grid. Also a type 2 fuzzy logic controller is used to control the DC-link capacitor in order to improve the dynamic response of the APF, and to ensure a well-smoothed DC-Link capacitor voltage. The gained benefits from these proposed control algorithms are the main contribution in this work. The proposed control scheme is implemented on a small-scale wind energy conversion system (WECS) controlled by a dSPACE 1104 card. Experimental results show that the proposed T2FLC maintains the DC-Link capacitor voltage within the limit for injecting the power into the grid. In addition, the PCC of the APF guarantees a flexible settlement of real power exchanges from the WECS to the grid with a high power factor operation.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.739-743
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• 2000

With significant development of power electronics technology the proliferation of nonlinear loads such as such as static power converters has deteriorated power quality in power transmission distribution systems. Notably voltage harmonics resulting from current harmonies produced by the nonlinear loads have become a serious problem in many systems Moreover momentary interruptions and voltage sags are responsible for many of the power quality problems found in typical industrial plants. Int his paper proposed 3 phase hybrid series active power filter is not only for harmonic compensation but also for harmonic isolation between supply and load and for voltage regulation and imbalance compensation Through computer simulations we have verified the effectiveness of the proposed system.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.883-887
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• 1998

The goal of this paper is to present an instantaneous compensating power flow of active power filter(APF) by graphical method that could be practicable to compensate the power in both case of behaving in an instantaneous rectifying mode and an instantaneous inverting mode. To ensure the validity of the proposed method, computer simulation is achieved. Proposed method can be present more exquisite and physically meaningful power flow than conventional method in the instantaneous compensating power flow diagram of APF.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1357-1368
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• 2017

The lack of controllability over the wind causes fluctuations in the output power of the wind generators (WGs) located at the wind farms. Distribution Static Compensator (DSTATCOM) equipped with Battery Energy Storage System (BESS) can significantly smooth these fluctuations by injecting or absorbing appropriate amount of active power, thus, controlling the power flow of WGs. But because of the component aging and thermal drift, its harmonic filter parameters vary, resulting in performance degradation. In this paper, Quantitative Feedback Theory (QFT) is used as a robust control scheme in order to deactivate the effects of filter parameters variations on the wind power generation power smoothing performance. The proposed robust control strategy of the DSTATCOM is successfully applied to a microgrid, including WGs. The simulation results obviously show that the proposed control technique can effectively smooth the fluctuations in the wind turbines' (WT) output power caused by wind speed variations; taking into account the filter parameters variations (structural parameter uncertainties).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3425-3430
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• 2013

The fast-growing market in wireless communications has led to the development of multi-standard mobile terminals. In this paper, a frequency-tunable active RC bandpass filter for multi-standards wireless communication system is designed using an active inductor. The conventional bandpass filter design methods employ the high order filter or high quality factor Q to improve the stopband attenuation characteristics and frequency selectivity of the passband. The proposed bandpass filter based on the high Q active inductor has an improved frequency characteristics. The center frequency and gain of the designed bandpass filter is tuned by employing the tuning circuit. We have performed the simulation using TSMC $0.18{\mu}m$ process parameter to analyze the characteristics of the designed active RC bandpass filter. The bandpass filter with Q=20.5 has 90MHz half power bandwidth at the center frequency of 1.86GHz. Moreover, the center frequency of the proposed bandpass filter can be tuned between 1.86~2.38GHz for the multi-standards wireless communication system using the capacitor of the tuning circuit.