• Journal of Electrical Engineering and Technology
• /
• 제8권2호
• /
• pp.304-315
• /
• 2013

In this paper, analysis of cascaded H-bridge multilevel inverter in DTC-SVM (Direct Torque Control-Space Vector Modulation) based induction motor drive for FCEV (Fuel Cell Electric Vehicle) is presented. Cascaded H-bridge multilevel inverter uses multiple series units of H-bridge power cells to achieve medium-voltage operation and low harmonic distortion. In FCEV, a fuel cell stack is used as the major source of electric power moreover the battery and/or ultra-capacitor is used to assist the fuel cell. These sources are suitable for utilizing in cascaded H-bridge multilevel inverter. The drive control strategy is based on DTC-SVM technique. In this scheme, first, stator voltage vector is calculated and then realized by SVM method. Contribution of multilevel inverter to the DTC-SVM scheme is led to achieve high performance motor drive. Simulations are carried out in Matlab-Simulink. Five-level and nine-level inverters are applied in 3hp FCEV induction motor drive for analysis the multilevel inverter. Each H-bridge is implemented using one fuel cell and battery. Good dynamic control and low ripple in the torque and the flux as well as distortion decrease in voltage and current profiles, demonstrate the great performance of multilevel inverter in DTC-SVM induction motor drive for vehicle application.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.985_986
• /
• 2009

LED 조명시스템의 구동드라이브는 크게 1단 방식과 2단 방식으로 구분할 수 있다. 1단 방식은 경제성은 있으나 LED 출력제어에 역률 보정을 하지 못하는 반면, 2단 방식은 LED 출력제어와 함께 역률 보정은 가능하나 회로가 복잡하여 경제성에 약점을 안고 있다. 본 논문에서는 입력측 역률을 개선하고 고조파 발생을 억제하기 위한 능동역률 개선회로와 함께 능동 클램프 방식의 플라이백 컨버터 방식을 이용하여 2차측 출력을 동시에 제어할 수 있는 단일단 형태의 구동 드라이브를 구성하여 시뮬레이션과 실험을 통해 제작 단가 절감 효과와 시스템 효율 향상을 검증하였다.

• 전기학회논문지P
• /
• 제60권2호
• /
• pp.72-75
• /
• 2011

In this paper, the voltage across the LED system supplied by positive voltage of power supply system the power consumption of the LED itself, and uses a lot of transformers and analog devices, such as converter startup problems and constant temperature even when the voltage driving abnormally LED current in the destruction caused by the flow of a lot of problems can occur. In this paper, we obtain the technology of consistent current using PWM(pulse width modulation) mode in order to minimize analog devices and eventually discuss the technology to develop consistent output converter using power drive IC.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
• /
• pp.1642-1645
• /
• 2007

The brightness of LED changes according to the current flowing through LEDs. The current mirror was used to drive LEDs effectively. The reference current of the current mirror was usually controlled by the resistor but the size of this resistor is very large and this resistor consumes too much power for high power LED backlight driving. The reference current of the current mirror LED driver was controlled by using flyback converter at small size with low power consumption in this paper. The concept of active current source was presented.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2008년도 추계학술대회 논문집
• /
• pp.105-107
• /
• 2008

LED driver is important for reliable LED lighting system. A variety of ICs for LED driver are supplied by almost all semiconductor company The types and performances are too diverse to collect proper IC and use efficiently. This paper classifies driver IC according to the usage for each application area and the circuit topology. Finally, the paper shows several representative ICs for main applications with notice of important performance.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제15권3호
• /
• pp.390-396
• /
• 2015

This paper proposes a method to reduce flicker when running an AC-power direct-drive type multiple string LED driver IC. The proposed method greatly decreases flicker using one capacitor and P-type MOSFET transistor (PMOS). The flicker index (FI) was reduced by over 40% through experiments, and less than half of the conventional external components are used in the passive valley fill circuit, which gives an advantage in the cost and utilization in the design of LED lighting modules. The 0.35 um 700 V BCD process was used to manufacture this LED driver.

• 조명전기설비학회논문지
• /
• 제27권10호
• /
• pp.15-20
• /
• 2013

In this paper, wireless power transfer system using the magnetic resonance was designed and applied to LED lighting for implementation of wireless lighting. This lighting was made by the converted DC driving type and the direct AC driving type. In the former, transferred AC power was rectified into DC and regulated to the specified voltage value, which leads to produce the loss at the rectifying and regulating circuit. In the latter, wireless-transferred AC power was directly applied to LED, which get rid of the loss derived from the additional circuit. For the efficiency-comparison between the former and the latter, the power at each stage was measured when the same optical output radiated from LED lighting part. The result revealed that the direct AC driving type had 18% higher efficiency than the DC driving type and confirmed that LED lighting using magnetic resonance wireless power transfer system can be efficient by direct AC power supply. And the direct AC driving type had the simple circuit structure and the simple LED lighting formation, so this can leads to various application.

• Journal of Power Electronics
• /
• 제17권2호
• /
• pp.315-322
• /
• 2017

LED is a promising new generation of green lighting with the advantages of high efficiency, good optical performance, long lifetime and environmental friendliness. A pulsating current can be used to drive LEDs. However, current with a high peak-to-average ratio is unfavorable for LEDs. A novel control scheme for the ac-dc critical conduction mode (CRM) flyback LED driver is proposed in this paper. By using the input voltage, output voltage and average output current to control the turn-on time of the switch, the peak-to-average ratio of the output current can be reduced. The operation principle is analyzed and an implementation circuit is put forward. Experimental results show the effectiveness of the proposed scheme.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2011년도 추계학술대회
• /
• pp.193-194
• /
• 2011

This paper describes a control method to minimize the filter capacitor of a PFC AC/DC converter for LED driver. The rectified secondary voltage of the transformer has 120Hz ripple unlike the conventional converter for the LED drive. Therefore, the filter capacitor can be minimized and this provides reduced cost, low switching loss, and long life of the converter.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2011년도 전력전자학술대회
• /
• pp.9-10
• /
• 2011

This paper describes a control method to minimize the filter capacitor of a AC/DC converter for LED driver. The rectified secondary voltage of the transformer has 120Hz ripple unlike the conventional converter for the LED drive. Therefore, the filter capacitor can be minimized and this provides reduced cost, low switching loss, and long life of the converter.