This paper presents an optimal design for the inner current-control loop of the continuous current conduction mode (CCM) power factor correction (PFC) stage, which can be used as the front stage of the two-stage AC/DC telecom power supply. The conventional single-phase CCM-PFC boost converter is implemented with proportional–integral (PI) controllers in both the voltage and current-control loops to regulate the output DC voltage to the specified value and to ensure the input current follows the input voltage, which offers a converter with a high-power factor (PF) and low current total harmonic distortion (THD). However, due to the slow dynamic response of the PI controller at the zero-crossing point of the input supply current, the input current cannot fully follow the input voltage, which leads to high THD. In this paper, we investigate a digitally controlled PFC converter with an optimally designed inner current-control loop using a doubly-fed control loops integral-proportional (IP) controller to reduce the THD and to offer an input current with a unity PF. For the economic design of a digitally controlled PFC converter, two isolated AC and DC voltage sensors are designed for interfacing with the microcontroller unit (MCU). PSIM software as well as experimental prototype was used to test the converter performance using the proposed designed current controllers and isolated voltage sensors. We achieved a high-power-density, digitally controlled, telecom PFC stage with a power factor more than 99% and THD of about 5.50%.

Air conditioning system of electric vehicles has new change as the internal combustion engine is being replaced with electrified AC motor. With large amount of batteries installed at the bottom of frame, the conventional compressor, which is belt-driven, can be removed, and another AC motor can play the role for air conditioning in electric vehicles. From this change, the system efficiency would be improved since it is possible to control the electrified compressor independently from traction system in contrast with the belt-driven compressor. As a result, by applying the electrified compressor for air conditioning system, the whole system can achieve better efficiency and longer driving distance, which is most important in electric vehicles. In this paper, 3-phase interior permanent magnet synchronous motor (IPMSM) was designed using lumped-parameter model and finite element method.

현재 대부분의 도시철도 추진시스템에 사용되고 있는 3상 유도전동기는 매입형 영구자석 동기전동기에 비하여 낮은 출력밀도의 특성이 있으며, 전동기 또는 인버터 스위치의 한 상에서 고장이 발생할 경우 추진시스템의 동작이 불가능한 단점이 있으므로 이를 개선하는 방안이 요구되고 있다. 따라서, 본 논문에서는 현재의 도시철도용 3상 유도전동기 기반의 추진시스템이 가지고 있는 단점들을 개선할 수 있는 180kW급 6상 영구자석 보조형 동기전동기 모델을 제안하였다. 6상 영구자석 보조형 동기전동기의 설계를 위하여 자기회로 모델과 유전알고리즘을 이용한 최적설계 과정을 제시하였으며, 유한요소분석을 이용하여 무부하 및 부하운전 성능 그리고 정상 및 고장 조건에서의 성능을 비교하였다. 또한, 기존에 설계된 도시철도용 3상 영구자석 보조형 동기전동기와 6상 영구자석 보조형 동기전동기의 유한요소해석 결과를 비교하여 6상 동기전동기의 장점을 분석하였다.

Air conditioning system of electric vehicles has new change as the internal combustion engine is being replaced with electrified AC motor. With large amount of batteries installed at the bottom of frame, the conventional compressor which is belt-driven can be removed and another AC motor can play the role for air conditioning in electric vehicles. From this change, the system efficiency would be improved since it is possible to control the electrified compressor independently from traction system in contrast with the belt-driven compressor. As a result, by applying the electrified compressor for air conditioning system, the whole system can achieve better efficiency and longer driving distance, which is most important in electric vehicles. In this paper, 3-phase interior permanent magnet synchronous motor (IPMSM) was designed using lumped-parameter model and finite element method.