• ETRI Journal
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• 제44권4호
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• pp.695-707
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• 2022

As for the insufficient nature of the fossil fuel resources, the renewable energies as alternative fuels are imperative and highly heeded. To deliver the required electric power to the industrial and domestic consumers from DC renewable energy sources like fuel cell (FC), the power converter operates as an adjustable interface device. This paper suggests a new boost structure to provide the required voltage with wide range gain for FC power source. The proposed structure based on the boost converter and the quazi network, the so-called SBQN, can effectively enhance the FC functionality against its high operational sensitivity to experience low current ripple and also propagate voltage and current with low stress across its semiconductors. Furthermore, the switching power losses have been decreased to make this structure more durable. A full operational analysis of the proposed SBQN and its advantages over the conventional and famous structures has been compared and explained. Furthermore, a prototype of the single-phase converter has been constructed and tested in the laboratory.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.523-524
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• 2008

Proposed battery charger is a economic candidate because that is simple and small size. The circuit has linearly operational power stage. That use small size buffer with small driving current and large power MOS gate capacitance. The simulation result show that charging current is stable and has low ripple.

• 한국태양에너지학회 논문집
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• 제32권6호
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• pp.106-112
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• 2012

As a fuel cell converts the chemical energy of the fuel cell into electrical energy by electrochemical reaction, the fuel cell system is uniquely integrated technique including fuel processor, fuel cell stack, power conditioning system. The residential fuel cell-PCS(Power Conditioning System) needs to convert efficiently the DC current produced by the fuel cell into AC current using single-phase DC-AC inverter. A single-phase DC-AC inverter has naturally low frequency ripple which is twice frequency of the output current. This low frequency(120Hz) ripple reduces the efficiency of the fuel cell. This paper presents notch filter with IP voltage controller to reject specific 120Hz current ripple in single-phase inverter. The notch filter is designed that suppress just only specific frequency component and no phase delay. Finally, the proposed notch filter design method has been verified with computer simulation and experimentation.

• 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.

• 전력전자학회논문지
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• 제9권2호
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• pp.126-133
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• 2004

본 연구에서는 저 비용 응용분야에 적합한 4스위치 3상 BLDC 전동기의 새로운 전류 제어 알고리즘을 제안하였다. 4스위치 시스템에서 빠른 속도 및 토크 응답 그리고 적은 토크 리플과 같은 좋은 동작 특성을 얻기 위한 기준 전류 발생 기법을 제안하였다. 특히, 제안한 기법은 전류 전환시 발생되는 토크 리플을 현저히 저감시켜 4스위치 시스템을 산업 응용 분야에 보다 널리 적용할 수 있을 것으로 기대한다.

• Journal of Power Electronics
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• 제17권3호
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• pp.590-600
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• 2017

This paper presents a ripple-free input current modified interleaved boost converter for high step-up applications. By integrating dual coupled inductors and voltage multiplier techniques, the proposed converter can reach a high step-up gain without an extremely high turn-ON period. In addition, a very small auxiliary inductor employed in series to the input dc source makes the input current ripple theoretically decreased to zero, which simplifies the design of the electromagnetic interference (EMI) filter. In addition, the voltage stresses on the semiconductor devices of the proposed converter are efficiently reduced, which makes high performance MOSFETs with low voltage rated and low resistance $r_{DS}$(ON) available to reduce the cost and conduction loss. The operating principles and steady-state analyses of the proposed converter are introduced in detail. Finally, a prototype circuit rated at 400W with a 42-50V input voltage and a 400V output voltage is built and tested to verify the effectiveness of theoretical analysis. Experimental results show that an efficiency of 95.3% can be achieved.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권12호
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• pp.813-820
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• 2000

A technique to suppress the low frequency ripple voltage of the DC output in three phase buck diode converter is presented in this paper. The proposed pulse frequency modulation methods and duty ratio modulation methods are employed to regulate the output voltage of the buck diode converter and guarantee zero-current-switching(ZCS) of the switch over the wide load range. The proposed control methods used in this paper provide generally good performance such as low THD of the input line current and unity power factor. In addition, control methods can be effectively used to suppress the low frequency ripple voltage appeared in the dc output voltage. The harmonic injection technique illustrates its validity and effectiveness through the simulations and experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.806-807
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• 2011

This paper presents a new sensorless controller used with both the classical sliding mode observer(SMO) and the rate of current change in order to a reduced torque ripple for switched reluctance motor (SRM) sensorless drives. The new sensorless scheme consists of a sliding mode observer (SMO)-based position sensorless approach for high speeds along with a low-resolution discrete the rate of current change for low speeds and standstill. The new position estimation resets between the SMO and the low-resolution of current change according to the speed sign and the position error difference between the SMO and the low-resolution rate of current change. The simulation results show the robustness of this new high performance sensorless control approach with the hybrid sensorless control topology.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.305-308
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• 2000

A technique to suppress the low frequency ripple voltage of the DC output in three phase buck diode rectifiers is presented in this paper. The proposed pulse frequency modulation methods and duty ratio modulation methods are employed to regulate the output voltage of the buck diode rectifiers and guarantee zero-current -switching(ZCS) of the switch over the wide load range The proposed control methods used in this paper provide generally good performance such as low THD of the input line current and unity power factor. IN addition control methods can be effectively used to suppress the low frequency ripple voltage appeared in the dc output voltage. The harmonic injection technique illustrates its validity and effectiveness through the simulations.

• Journal of Power Electronics
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• 제11권5호
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• pp.726-733
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• 2011

BLDC Motors are widely used in various speed control applications due to their ease of control and low cost. Generally, the unipolar PWM method is used for speed control applications. However, the unipolar PWM method has a current spike problem in the braking operation which can be a problem in speed reversal which generally happens in position control applications. However, the current spike problem can be solved by the conventional bipolar PWM method. Although the current spike problem can be solved, the conventional bipolar PWM method has the problem of a large current ripple. In this paper, a novel bipolar PWM method is proposed to solve this problem. The current ripple and the current spike problems are analyzed in this paper for the unipolar and bipolar PWM methods. At last, the merits of the proposed bipolar PWM method are proven by experiment.