다상 교호 승압컨버터의 정상상태 해석 및 전압제어
Steady state analysis and voltage control of multi-phase interleaved boost converte
다상교호 승압컨버터 전압제어 상태방정식 전기공학;
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The interleaved boost converter(IBC) is composed of several identical boost converters connected in parallel. The converters are controlled by the interleaved switching signals, which have the same switching frequency and the same phase shifting. By virtue of paralleling the converters, the input current can be shared, so that high reliability and efficiency in power electronic systems can be obtained. As a consequence of the interleaving operation, the IBC exhibits both lower current ripple at the input side and lower voltage ripple at the output side. Therefore, the size and losses of the filtering stages can be reduced, and the switching and conduction losses as well as EMI levels can be significantly decreased. However, the number of components, such as inductor, active and passive switches, increases as the IBC has more phases in parallel. The dimension of state and control input becomes also higher and it is more difficult to analyze and investigate the operating characteristics at both steady and transient states. The N-phase IBC has been modeled and analyzed by using a signal flow graph at steady state in . Some useful expressions such as conversion ratio and efficiency are also presented. Using the signal flow graph model, it is, however, difficult to analyze the unbalance in current sharing and the ripples in input current and output voltage. The graphical model of IBC becomes much complex as the number of phase increases and the interleaved switching pattern in also restrictive. The input current ripple has been derived for 2-phase IBC with coupled inductors. It was shown that increasing the number of phase in IBC could significantly reduce the input and output current ripples. The current ripples should be, however, derived again for other N-phase IBC. This job is very tedious and complex, and it tends to make error in the results. Unfortunately, there are no general and analytical expressions for steady-state operation of the N-phase IBC in the literatures. When the IBC is designed, it is necessary and important to know the steady-state characteristics. In this paper, the average state-space model of the N-phase IBC is presented under the continuous inductor current mode, and we derive the generalized and explicit expressions of rippled magnitudes of the input and inductor current are derived, and the condition for the minimum-rippled operation of input current is presented. It is analyzed also the current unbalance due to the parameter mismatch among the paralleled converters. Furthermore, the explicit expression for the output voltage ripple is derived and analyzed.