• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2005년도 춘계학술대회
• /
• pp.132-135
• /
• 2005

A modular photovoltaic PCS with high-frequency isolation is proposed. The proposed system consists of a SEPIC converter and a full-bridge inverter. Using the power slope versus voltage of the PV array, the MPPT controller is proposed that produces a smooth transition to the maximum power point. The disturbance of the line voltage is detected using a fast sensing technique. Experimental results obtained on a 500W prototype show high performance such as almost unity power factor, $90\%$ power efficiency, $3.6\%$ THD.

• 전력전자학회논문지
• /
• 제24권1호
• /
• pp.56-61
• /
• 2019

In this study, a reduction method of leakage current in a three-level photovoltaic power-conditioning system (PCS) is proposed and verified by simulation and experiment. Leakage current generation is analyzed through an equivalent model of the common mode voltage considering a significant parasitic capacitance existing between the photovoltaic array and ground. A leakage current reduction method using pulse-width modulation (PWM) method is also proposed, and a 10-kW three-level photovoltaic PCS simulation and experiment is performed with a $1{\mu}F$ parasitic capacitor based on 100 nF/kW. The proposed method using the PWM method is verified to reduce the leakage current by 73% compared with the conventional PWM method.

• 전력전자학회논문지
• /
• 제13권2호
• /
• pp.119-127
• /
• 2008

본 논문에서는 모듈형 계통연계 태양광 PCS (photovoltaic power conditioning system)를 제안하였다. 능동-클램프 회로와 듀얼 직렬-공진 정류 회로를 이용하여 높은 입출력 전압 비를 효과적으로 구현하고 효율을 높인 승압형 DC-DC 컨버터를 제안하였다. 최대 전력점 추종 특성을 개선한 IncCond (incremental conductance) 방식의 MPPT (maximum power point tracking) 알고리즘을 사용하였다. 이 때 DC 전류 센서를 사용하지 않고 태양전지 모듈 (PV module)의 전류를 예측한다. 선형화 기법을 사용한 출력 전류 제어기로 인버터를 제어하여 단위 역률을 실현하였다. 모든 알고리즘과 제어기를 하나의 마이크로컨트롤러로 구현하고 제안된 DC-DC 컨버터와 제어기의 우수성을 실험을 통해 검증하였다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2006년도 춘계학술대회
• /
• pp.225-227
• /
• 2006

The demand for developing the compact and cost effective commercial version of the photovoltaic power conditioning system(PCS) is now increasing and several commercial products are on the markets. In this paper, several design results of 10kW rated grid-tied photovoltaic PCS system are introduced, and several test results for the system evaluation are also described. The test results verified the validity of the proposed photovoltaic PCS system.

• Journal of Power Electronics
• /
• 제7권2호
• /
• pp.174-180
• /
• 2007

In this paper, a simple control method for two-stage utility grid-connected photovoltaic power conditioning systems (PCS) is proposed. This approach enables maximum power point (MPP) tracking control with post-stage inverter current information instead of calculating solar array power, which significantly simplifies the controller and the sensor. Furthermore, there is no feedback loop in the pre-stage converter to control the solar array voltage or current because the MPP tracker drives the converter switch duty cycle. This simple PCS control strategy can reduce the cost and size, and can be utilized with a low cost digital processor. For verification of the proposed control strategy, a 2.5kW two-stage photovoltaic grid-connected PCS hardware which consists of a boost converter cascaded with a single-phase inverter was built and tested.

• 전력전자학회논문지
• /
• 제12권5호
• /
• pp.355-363
• /
• 2007

본 논문에서는 무변압기형 3상 계통연계 PV PCS (photovoltaic power conditioning system)를 제안하였다. 태양전지의 국소 최대 전력점에서 발전하는 것을 방지하여 최대 전력점에서 발전을 하도록 개선한 P&O (perturb and observe) 방식의 MPPT (maximum power point tracking) 알고리즘을 제안하였다. 3상 전압형 인버터를 외부 직류 링크 전압제어기, 내부 전류제어기, 그리고 마이크로컨트롤러로 구현하기에 적합하도록 간단화한 공간벡터 변조법을 통해 제어하여 3상 계통연계 시 단위 역률을 실현하였다. 그리고 시스템의 안정성 향상과 역률 개선을 위해 직류 링크 전압을 더 빠르고 정확하게 제어하기 위한 알고리즘을 제안하였다. 모든 알고리즘과 제어기를 하나의 마이크로컨트롤러로 구현하고 제안된 알고리즘과 제어기의 우수성을 실험을 통해 검증하였다.

• 한국산업융합학회 논문집
• /
• 제23권3호
• /
• pp.491-498
• /
• 2020

Recently, In the production line of batteries, charge and discharge tests are essential to verify battery characteristics. In this case, the battery charging uses a unidirectional AC/DC converter capable of output voltage and current control, and the discharge uses a resistive load. Since this method consumes energy during discharge, it must be replaced with a bi-directional AC/DC converter system capable of charging and discharging. Although it is difficult to replace the connected inverter part of the bi-directional AC/DC converter system due to the high cost, the spread of the solar-connected inverter rapidly increases as the current solar supply business is activated, and thereby the solar-connected type Inverter prices are plunging. If it can be used as a power converter for battery discharge without program modification of the solar-powered inverter, it will have competition. In this paper, propose a new battery discharge system using a combination of a photovoltaic DC/DC simulator and photovoltaic PCS using a battery to be used as a power converter for battery discharge without program modification of a low-cost photovoltaic inverter. In addition, propose an optimal solar characteristic curve for the stable operation of PCS. The validity of the proposed system was verified using a 500[W] class solar DC/DC simulator and a solar PCS prototype.

• 전기학회논문지
• /
• 제67권3호
• /
• pp.479-484
• /
• 2018

This paper describes domestic technical standard of Photovoltaic(PV) PCS(Power Conditioning Systems)-Characteristics of the utility interface. This standard tests utility compatibility and personnel safety and equipment protection of PV inverter performance functions. Especially utility compatibility part includes test items of 1)voltage, current and frequency, 2)normal voltage operating range, 3)DC injection, 4)normal frequency operating range, 5)harmonics and 6)waveform distortion, 7)power factor of PV inverter. Therefore in this paper each test item of domestic technical standard is studied and analyzed and finally full tested by PV inverter performance function.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 추계학술대회 논문집
• /
• pp.289-292
• /
• 2007

The modular line-connected photovoltaic PCS (power conditioning system) is proposed. The proposed system consists of a step-up DC-DC converter and a full-bridge inverter. A step-up DC-DC converter using a dual series-resonant rectifier circuit and a active-clamp circuit is proposed to achieve a high efficiency and a high input-output voltage ratio efficiently. An IncCond (incremental conductance) MPPT (maximum power point tracking) algorithm that improves MPPT characteristic is used. By control a inverter using a linearized output current controller, a unity power factor is achieved. All algorithms and controllers are implemented on a single-chip microcontroller and the superiority of the proposed algorithms and controllers is proved by experiments.

• Journal of Power Electronics
• /
• 제11권4호
• /
• pp.561-567
• /
• 2011

This paper presents a high-efficiency power conditioning system (PCS) for grid-connected photovoltaic (PV) modules. The proposed PCS consists of a step-up DC-DC converter and a single-phase DC-AC inverter for the grid-connected PV modules. A soft-switching step-up DC-DC converter is proposed to generate a high DC-link voltage from the low PV module voltage with a high-efficiency. A DC-link voltage controller is presented for constant DC-link voltage regulation. A half-bridge inverter is used for the single-phase DC-AC inverter for grid connection. A grid current controller is suggested to supply PV electrical power to the power grid with a unity power factor. Experimental results are obtained from a 180 W grid-connected PV module system using the proposed PCS. The proposed PCS achieves a high power efficiency of 93.0 % with an unity power factor for a 60 Hz / 120 Vrms AC power grid.