• 조명전기설비학회논문지
• /
• 제26권6호
• /
• pp.16-28
• /
• 2012

This paper proposes a quasi Z-source converter(QZSC) with a diode-capacitor output filter to improve the output DC voltage boost ability. The proposed converter has the same quasi Z-source network topology compared with the conventional converter. But the proposed method is adopted a diode-capacitor filter as its output filter, since the conventional method is used an inductor-capacitor as its output filter. Under the condition of the same input-output DC voltage, the proposed method has more lower shoot-through duty ratio than the conventional method. Also, because the proposed converter has same voltage boost factor under lower shoot-through duty ratio compared with the conventional converter, the proposed converter can be operated with the lower capacitor voltage of Z-source network and the lower input current. To confirm the validity of the proposed method, PSIM simulation and a DSP based experiment were performed to acquire the output DC voltage 120[V] under the input DC voltage 80[V]. And the capacitor voltage and inductor current in Z-source network, the output voltage of each converter were compared and discussed.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1997년도 전력전자학술대회 논문집
• /
• pp.239-242
• /
• 1997

In this paper, the new filter that reduced output ripple to zero is proposed. This filter is composed of transformer and capacitor. The operating mode is verified with theoretical analysis of low ripple filter and computer simulation. DC-DC converter of input voltage DC 100[V], output 30[V]/30[A], switching frequency 20[KHz] is manufactured. In the result, computer simulation analysis is same to experimental result.

• 대한전기학회논문지
• /
• 제45권1호
• /
• pp.30-41
• /
• 1996

Current Source(CS) PWM converter is appropriate for the magnet power supply system which requests high power and high precision current control. Input and output filters should be installed to eliminate the current or voltage harmonics caused by the PWM switching for the CS PWM converter. But the input/output filters limit the output DC current range and may destroy the system with filter resonance, and make the system equation more complicated. In this paper, systematic and simple filter design method which considers not only the harmonic attenuation but also the total system good transfer function characteristics in the dc filter. The simulated and experimental results verify the proposed theory. (author). refs., figs., tabs.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
• /
• pp.307-310
• /
• 2002

A design for the input filter and the output filter of a single-phase UPS system is proposed. And also, this paper describes a reduction of the DC voltage ripple of a single-phase UPS. The input power of proposed UPS fluctuates with twice frequency of the utility source, which causes DC voltage fluctuation. The reduction of the DC voltage fluctuation requires a large DC link capacitor. The proposed method uses a LC series resonant filter paralleled with a conventional smoothing capacitor. The effectiveness of the proposed method was confirmed by simulation results.

• Journal of Power Electronics
• /
• 제17권6호
• /
• pp.1391-1401
• /
• 2017

In this paper, a secondary resonance half-bridge dc-dc converter with an inductive output filter is presented. The primary side of such a converter utilizes asymmetric pulse width modulation (APWM) to achieve zero-voltage switching (ZVS) of the switches, and clamps the voltage of the switch to the input voltage. In addition, zero current switching (ZCS) of the output diode is achieved by a half-wave rectifier circuit with a filter inductor and a resonant branch in the secondary side of the proposed converter. Thus, the switching losses and diode reverse-recovery losses are eliminated, and the performance of the converter can be improved. Furthermore, an inductive output filter exists in the converter reduce the output current ripple. The operational principle, performance analysis and design equation of this converter are given in this paper. The analysis results show that the output diode voltage stress is independent of the duty cycle, and that the voltage gain is almost linear, similar to that of the isolation Buck-type converter. Finally, a 200V~380V input, 24V/2A output experimental prototype is built to verify the theoretical analysis.

• 조명전기설비학회논문지
• /
• 제21권2호
• /
• pp.54-63
• /
• 2007

최근 저전압 대전류 출력 특성을 갖는 연료전지를 위한 새로운 발전시스템으로 주목받고 있다. 연료전지 발전시스템에서는 DC-DC 승압용 컨버터와 DC-AC 인버터가 필요하다. 그러므로 본 논문에서는 연료전지의 전압을 $380[V_{DC}]$로 승압하기 위한 절연형 DC-DC 컨버터와 단상 $220[V_{AC}]$로 변환하기 위한 LC필터를 가진 PWM 인버터로 구성된 전력변환장치를 제안하였다. 특히 제안한 고주파 절연형 ZVZCS PWM DC-DC 컨버터는 환류 다이오드를 포함한 탭부 인덕터 필터를 이용하여 순환 전류를 저감시켰으며, 스위치 및 변압기의 턴-온, 턴-오프시에 오버슈트 전압이나 과도현상이 발생하지 않는다. 그리고 넓은 출력 전압 조정에도 효율을 $93{\sim}97[%]$정도 얻을 수 있으며, 출력 부하전류의 변화에 대해 거의 일정한 출력 전압 특성을 가졌다.

• Journal of Power Electronics
• /
• 제9권3호
• /
• pp.430-437
• /
• 2009

This paper presents the dynamic characteristics of buck and buck-boost dc-dc converters with digital filters. At first, the PID, the minimum phase FIR filter and the IIR filter controls are discussed in the buck dc-dc converter. Comparisons of the dynamic characteristics between the buck and buck-boost converters are then discussed. As a result, it is clarified that the superior dynamic characteristics are realized in the IIR filter method. In the buck converter, the undershoot is less than 2% and the transient time is less than 0.4ms. On the other hand, in the buck-boost converter, the undershoot is about 3%. However, the transient time is approximately over 4ms because the output capacitance is too large to suppress the output voltage ripple in this type of converter.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.351-354
• /
• 2006

Recently, a fuel cell with low voltage and high current output characteristics is remarkable for new generation system It needs both a DC-DC step-up converter and DC-AC inverter to be used in fuel cell generation system Therefor, this paper, consists of an isolated DC -DC converter to boost the fuel cell voltage 380[$V_{DC}$] and a PWM inverter with LC filter to convent the DC voltage to single phase 220[$V_{AC}$]. Expressly, a tapped inductor filter with freewheeling diode is newly implemented in the output filter of the proposed high frequency isolated ZVZCS PWM DC-DC converter to suppress circulating current under the wide output voltage regulation range, thus to eliminate the switching and transformer turn-on/off over-short voltage or transient phenomena Besides the efficiency of 93-97[%]is obtained over the wide output voltage regulation ranges and load variations.

• Journal of Power Electronics
• /
• 제11권6호
• /
• pp.793-800
• /
• 2011

This paper investigates the operational modes of buck dc-dc converters and their energy transmission methods. The operational modes of such converters are classified in two types, discontinuous conduction mode (DCM) and continuous conduction mode (CCM). In this paper, the critical inductance relation of DCM and CCM is determined. The equations of the output voltage ripple (OVR) for each mode are obtained for a specific input voltage and load resistance range. The maximum output voltage ripple (MOVR) is also obtained for each mode. The filter size is decreased and the minimum required inductance value is calculated to guarantee the minimization of the MOVR. The experimental and simulation results in PSCAD/EMTDC prove the correctness of the presented theoretical concepts.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
• /
• pp.1207-1208
• /
• 2006

Recently, a fuel cell with low voltage and high current output characteristics is remarkable for new generation system. It needs both a DC-DC step-up converter and DC-AC inverter to be used in fuel cell generation system. Therefor, this paper, consists of an isolated DC-DC converter to boost the fuel cell voltage 380[VDC] and a PWM inverter with LC filter to convent the DC voltage to single-phase 220[VAC]. Expressly, a tapped inductor filter with freewheeling diode is newly implemented in the output filter of the proposed high frequency isolated ZVZCS PWM DC-DC converter to suppress circulating current under the wide output voltage regulation range, thus to eliminate the switching and transformer turn-on/off over-short voltage or transient phenomena. Besides the efficiency of 93-97[%] is obtained over the wide output voltage regulation ranges and load variations.