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PWAM 방식을 이용한 공조시스템용 인버터의 THD 저감 방법
임승범(Seung-Beom Lim),이윤하(Yun-Ha Lee),전찬용(Chan-Yong Zun) 전력전자학회 2011 전력전자학술대회 논문집 Vol.2011 No.7
The HVAC(Heating Ventilation and Air conditioning) system is controlled by two ways, one is ON/OFF control and the other is PWM inverter with V/F. Control of blower with the use of PWM inverter has quite some benefits such as the capability of changing speed, high efficiency and reduced noise level compared with ON/OFF control. But if blower is operated at low speed, high THD generated by decrease of ma, and output voltage lowered in proportion to frequency. To solve these problems, filter should be installed at the output stage of inverter, which can decrease THD but has problems such as increase of volume size and additional braking resistance. This paper proposes the PWAM method which can reduce THD instead of installing the filter at the output stage of inverter. The proposed PWAM method is an inverter modulation method that fixes the modulation index of inverter to reduce THD by varying DC link voltage of inverter unlike conventional PWM method. Finally, the validity of proposed PWAM methods verified by experiments.
UPS 기능을 갖는 A/C Blower용 Inverter 시스템 개발
임승범(Seung-Beom Lim),이윤하(Yun-Ha Lee),지준근(Jun-Keun Ji),목형수(Hyung-Soo Mok),홍순찬(Soon-Chan Hong) 전력전자학회 2010 전력전자학술대회 논문집 Vol.2010 No.11
The HVAC(Heating Ventilation and Air Conditioning) system is only controlled by turn on/turn off operations against to AC 380V input. Therefore, the efficiency of the system is reduced and noise occurs. Also, the blower is shut down at the AC power failure. In this paper, the inverter system with UPS function for the A/C(Air Conditioning) blower is proposed. Proposed inverter system which is powered from the AC and DC voltage can control speed, operation mode, and soft-start time using CAN communication. In case of the CAN communication failure, RS-232 communication could be used to control the hardware directly by the engineer that can solve existing problems. To verify the validity of proposed inverter system, simulations and experiments are carried out.
임승범(Seung-Beom Lim),장주형(Ju-Hyeong Jang),김형중(Hyoung-Joong Kim) 한국조명·전기설비학회 2021 조명·전기설비학회논문지 Vol.35 No.8
In this paper, a high efficiency hybrid UPS based 3-level topology with ESS mode is proposed. The proposed hybrid UPS is a double conversion method that supplies stable power to the load while charging the battery, and automatically supplies power to the using the energy stored in the battery when the input power is unstable or power failure occurs. In addition, it has the advantage of being able to manage power by supplying power to the load using commercial power and battery power at the same time when the ESS mode is required for power shortage, peak load, or user convenience. Proposed UPS operates in four modes: normal mode, battery mode, ESS mode 1 and ESS mode 2. Also, if power factor improvement is required, the power factor of the opening can be improved by adjusting the phase of the input current. Finally, the usefulness of the proposed system is verified through experiments.
임승범(Seung-Beom Lim),장주형(Ju-Hyeong Jang),김지수(Ji-Soo Kim),김상현(Sang-Hyun Kim) 한국조명·전기설비학회 2021 조명·전기설비학회논문지 Vol.35 No.1
In this paper, an offline UPS for air conditioning equipment is proposed. The proposed offline UPS normally uses commercial power to supply power to the load while storing energy in the battery, and if there is a problem with the commercial power, it uses the energy stored in the battery to supply stable power to the load. This requires a fast detection method and a seamless transition method. Proposed UPS operates in four modes: normal mode, charging mode, battery mode, and ESS mode. The experiment confirmed the usefulness of the proposed product.