• Journal of Advanced Marine Engineering and Technology
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• 제28권2호
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• pp.200-209
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• 2004

The fuzzy control based on $\alpha$-level fuzzy set decomposition. It is known to produce quick response and calculating time of fuzzy inference. This paper derived the embodiment computational algorithm for defuzzification by min-max fuzzy inference and the center of gravity method based on $\alpha$-level fuzzy set decomposition. It is easy to realize the fuzzy controller hardware. based on the calculation formula. In addition. this study proposed a circuit that generates PWM actual signals ranging from fuzzy inference to defuzzification. The fuzzy controller was implemented with mixed analog-digital logic circuit using the computational fuzzy inference algorithm by min-min-max and defuzzification by the center of gravity method. This study confirmed that the fuzzy controller worked satisfactorily when it was applied to the position control of a dc servo system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.381-383
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• 2006

A novel online capacitance estimation method for a DC-link capacitor in a three-phase AC/DC/AC PWM converter is proposed. A controlled AC voltage with a lower frequency than the line frequency is Injected into the DC-link voltage, which then causes AC power ripples at the DC output side. By extracting the AC voltage and power components on the DC output side using digital filters, the capacitance can then be calculated using the recursive least squares method. The proposed method can be simply implemented with only software and no additional hardware. Experimental results confirm that the estimation error is less than 0.2%.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.343-346
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• 2002

In recent, complex SVPWM (Space Vector PWM) algorithm can be easily implemented by high performance microprocessor and DSP. Various SVPWM techniques are widely studied due to the advantages of low harmonic distortion and high use ratio of D.C. link voltage. Most of various studies for improving of VS-PWM inverter performance are concentrated about switching pattern and zero pulse pattern split algorithms. However, dc link voltage that is determined at rated load and speed conditions is not proper in the low speed and under rated load. In this paper, analysis of current ripple with digitally implemented SVPWM inverter is introduced according to link voltage. The optimal link voltage in the designed inverter system and load condition is provided in order to suppress output voltage error and current ripple. As remaining the effective voltage vector interval per sampling period sufficiently, additional voltage error and current ripple are suppressed. The proposed algorithm is verified through digital simulation and experimental results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.729-733
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• 2003

This paper proposed a novel current control strategy on active power filters using p-q-r instantaneous power theory which can compensate the line current harmonics and the neutral line current in unbalanced and/or distorted source conditions in three-phase four-wire systems. The proposed current control method is based on a sinusoidal PWM for fully-digital implementation which was compared with a hysteresis PWM. Simulation results showed good performance of the proposed current control strategy on shunt type APFs.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권9호
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• pp.615-621
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• 2004

This paper describes the design of a 2-phase stepping motor driver using CPLD. The driver IC such as L297, which is mostly used has some difficulties in PWM current control because of the switching noise of power MOSFETs. The switching noise causes current ripple and acoustic noise. To reduce the switching noise, we designed a digital filter using VHDL. Also we designed constant current method for 1-2 phase(half step) excitation to reduce the torque ripple. Experimental results show the effectiveness of the proposed method. It is enabling further enhancements of stepping motor drive technology broadening the range of applications for the stepping motors.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1341-1346
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• 2004

Basic design for single-phase active power filter, which aims at railway applications provided with PWM-controlled converters, is comprehensively studided and its performance is presented in this paper, Active power filters are used to compensate railway signaling and public telecommunication interference due to the high-order harmonic currents generated in railway traction locomotives. A type of hybrid digital filter which is composed of low pass filter and high pass filter is proposed so that the desired harmonic reference current with accurate magnitude and phase shift can be extracted from catenary line current. A design criteria to determine input inductor L and output capacitor C is also described, considering voltage, current. PWM pattern, and switching frequency of the main converters, Finally, computer simulation and DSP-based experiments resulted from laboratory test are presented.

• 조명전기설비학회논문지
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• 제26권3호
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• pp.61-68
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• 2012

This paper deals with a fault diagnosis algorithm for open faults in the switching devices of PWM inverter-fed IPMSM (Interior Permanent Magnet Synchronous Motor) drive. The proposed diagnostic algorithm is realized in the controller using the informations of three-phase currents or reference line-to-line voltages, without requiring additional equipments for fault detection. Under switch open fault conditions, the conventional dq model used to control an AC motor cannot directly be applied for the analysis of drive system, since three-phase balanced condition does not hold. To overcome this limitation, a fault model based on the line-to-line voltages is employed for the simulation studies. For comparative performance evaluation through the experiments, the entire control system is implemented using digital signal processor (DSP) TMS320F28335. Simulations and experimental results are presented to verify the validity of the proposed diagnosis algorithm.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.327-331
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• 2008

The problems of power factor and harmonics are occurred in converter system which used to SCRs and diodes as power semiconductor devices IGBT was solved that problem, maintain the input line current with sinusoidal wave current of input power source voltage. In this paper, three phase AC to DC boost converter that operates with unity power factor and sinusoidal input currents is presented. The current control of the converter is based on the space vector PWM strategy with fixed switching frequency and the input current tracks the reference current within one sampling time interval. Space vector PWM strategy for current control was materialized as a digital control method. By using this control strategy low ripples in the output voltage, low harmonics in the input current and fast dynamic responses are achieved with a small capacitance in the dc link.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2522-2524
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• 2000

In this paper, a controller design for ironless linear synchronous motor is proposed. The designed controller is mainly composed of speed and current control, which are carried out by the high-speed digital signal processor(DSP). In addition the PWM inverter is controlled by space voltage PWM method. This system is implemented using by 32-bit DSP(TMS32OC31), a high-integrated logic device(EPM940), and IPM(Intelligent Power Module) for compact and powerful system design. The experimental results show the effective performance of controller for careless linear synchronous motor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1196-1198
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• 2000

In this paper, a new approach for digital feedback control of PWM inverter is proposed, in which an output DB(Dead-Beat) control is achieved combined with a simple disturbance observer. The deadbeat controller, which is constructed multiple loop control scheme for PWM inverter, is used for fast transient response. The disturbance observer can make the disturbances be cancelled by adding feedforward compensating loop in controller. The simulation result show the proposed control scheme can achieved good voltage regulation against large load variations.