인덕턴스와 쇄교자속의 공간변화를 고려한 동기전동기의 유기전압고조파 분석 및 성능개선 설계

Abstract

These days the required speed and the torque of motors such as Integrated starter and generator (ISG) and traction motors are gradually increased because a smaller size and a higher power are demanded. As the speed and the torque of motors increase, induced voltage harmonics inevitably increase due to the partial saturation of electrical steel sheet. The induced voltage exceeds the input voltage results in the insufficient voltage. Accordingly, the current is distorted and decreased which causes the decrease in torque, in other words, reduction of output. Therefore, analyzing the cause of induced voltage harmonics can be the essential design factor for the design of synchronous motors. In this paper, components are separated from the induced voltage of the synchronous motor and the factors which have a great influence on the induced voltage harmonics are figured out. Furthermore, the design for performance improvement is conducted. First of all, the decrease in performance as the induced voltage exceeds the input voltage is explained. Secondly, the induced voltage is divided into three components to analyze the cause of induced voltage harmonics and the dominant factors for the generation of harmonics are analyzed according to the magnitude and angle of current. Consequently, the induced voltage generated by the spatial change of inductance and linkage flux are dominant to the induced voltage harmonics. However, the harmonics in case of applying the eccentric shape of rotor or controlling the ratio of electric loading and magnetic loading are analyzed. The design of reducing induced voltage harmonics is conducted by applying the methods. These methods can be effective for the reduction in the generation of harmonics as the magnitude and the spatial change of inductance decreased and the spatial change of linkage flux are reduced. The effect of controlling the ratio of magnetic and electric loadings on induced voltage harmonics is verified by FEM to check. Furthermore, the change in components of induced voltage harmonics is analyzed by FEM with the eccentric shape of rotor models and the effect of induced voltage harmonics on the performance of control is verified by the load test with manufactured motors. This paper deals with the method of analyzing induced voltage harmonics. This method can be applied to the initial design of all types of synchronous motors used in vehicles as well as interior permanent magnet synchronous motors. Therefore, the method can be useful to obtain the required performance in the design process.|최근 ISG(Integrated starter and generator)용이나 견인용 등 차량에 장착되는 동기전동기의 경량화, 고출력화로 인해 요구되는 구동속도와 토크가 증가하고 있다. 동기전동기의 구동속도와 토크가 증가하면 전기강판의 국부적인 포화로 인해 유기전압의 고조파가 필연적으로 증가한다. 고조파의 증가로 인해 유기전압이 입력전압을 초과하게 되면 전압부족현상으로 요구전압을 입력하지 못한다. 이로 인해 전류의 왜곡이나 저하현상이 생기고 이는 토크의 저하, 곧 출력의 저하로 이어진다. 따라서, 동기전동기를 설계함에 있어서 유기전압 고조파의 원인을 찾아 분석하는 것이 중요한 설계요인이 될 수 있다. 본 논문에서는 동기전동기의 유기전압의 구성성분을 분리하고 고조파의 원인을 분석했다. 또한, 이 원인을 바탕으로 성능을 개선한 설계를 수행하였다. 먼저 고조파로 인해 유기전압이 입력전압을 초과하였을 경우 나타나는 성능저하현상을 제시하였다. 그 다음 유기전압의 고조파 원인을 분석하기 위하여, 유기전압을 세 가지의 전압 성분으로 분리하였으며 전류의 크기와 위상의 변화로부터 고조파 발생에 지배적인 원인을 분석하였다. 결과적으로, 인덕턴스의 공간변화로부터 발생하는 유기전압과 쇄교자속의 공간변화로부터 발생하는 유기전압이 고조파 발생에 지배적이다. 한편, 장하비의 조절이나 회전자의 편심형상 적용이 유기전압의 어떤 성분에 고조파를 발생시키는지 분석하였고, 고조파의 발생을 저감시키는 성능개선 설계를 진행하였다. 이 방안들은 인덕턴스의 크기나 공간변화율, 쇄교자속의 공간변화율을 감소시키거나 정현화하는 방향으로 고조파의 발생 저감에 효과를 보인다는 것을 확인하였다. 부하를 고려한 동기전동기의 유기전압 고조파 분석 내용을 검증하기 위하여, 장하비의 조절한 모델들의 유한요소해석을 수행하여 유기전압의 고조파에 미치는 효과를 검증하였다. 또한, 회전자에 편심형상을 적용한 모델의 유한요소해석을 통해 분리된 유기전압 성분의 변화를 분석하고 제작된 전동기의 부하시험을 통해 유기전압의 고조파 성분이 제어성능에 미치는 영향을 검증하였다. 본 논문에서 다루는 유기전압의 고조파 분석방법은 매입형 영구자석동기전동기 뿐 아니라 차량에 장착되는 모든 형태의 동기전동기 초기설계단계에서 쉽게 검토가 가능하며 그 영향을 확인할 수 있어, 제어성능을 고려한 설계 진행시 실제 성능확보에 도움이 될 것으로 판단된다.; These days the required speed and the torque of motors such as Integrated starter and generator (ISG) and traction motors are gradually increased because a smaller size and a higher power are demanded. As the speed and the torque of motors increase, induced voltage harmonics inevitably increase due to the partial saturation of electrical steel sheet. The induced voltage exceeds the input voltage results in the insufficient voltage. Accordingly, the current is distorted and decreased which causes the decrease in torque, in other words, reduction of output. Therefore, analyzing the cause of induced voltage harmonics can be the essential design factor for the design of synchronous motors. In this paper, components are separated from the induced voltage of the synchronous motor and the factors which have a great influence on the induced voltage harmonics are figured out. Furthermore, the design for performance improvement is conducted. First of all, the decrease in performance as the induced voltage exceeds the input voltage is explained. Secondly, the induced voltage is divided into three components to analyze the cause of induced voltage harmonics and the dominant factors for the generation of harmonics are analyzed according to the magnitude and angle of current. Consequently, the induced voltage generated by the spatial change of inductance and linkage flux are dominant to the induced voltage harmonics. However, the harmonics in case of applying the eccentric shape of rotor or controlling the ratio of electric loading and magnetic loading are analyzed. The design of reducing induced voltage harmonics is conducted by applying the methods. These methods can be effective for the reduction in the generation of harmonics as the magnitude and the spatial change of inductance decreased and the spatial change of linkage flux are reduced. The effect of controlling the ratio of magnetic and electric loadings on induced voltage harmonics is verified by FEM to check. Furthermore, the change in components of induced voltage harmonics is analyzed by FEM with the eccentric shape of rotor models and the effect of induced voltage harmonics on the performance of control is verified by the load test with manufactured motors. This paper deals with the method of analyzing induced voltage harmonics. This method can be applied to the initial design of all types of synchronous motors used in vehicles as well as interior permanent magnet synchronous motors. Therefore, the method can be useful to obtain the required performance in the design process.