| Abstract |
In this paper, a dynamic voltage restorer (DVR) is presented based on a novel buck type PWMdirect ac-ac converter topology. The ac-ac converter used in proposed DVR has no commutationproblem because of using switch cell structure and coupled inductors, and therefore, it does not needto sense the input voltage polarity for safe commutation, which saves the cost of input voltage sensor.The proposed DVR also utilizes high-frequency-isolation in the direct ac-ac converter, to avoid theneed of the bulky line frequency (60 Hz) transformer. Although the proposed converter adds twocoupled inductors to solve the commutation problem, however, the size of the transformer and outputinductor can be reduced significantly. All the passive components in proposed DVR also experiencetwice the switching frequency, and the use of external fast recovery diodes allow to further increasethe switching frequency, which can significantly reduce the passive component sizes. Moreover, theac-ac converter used in proposed DVR has both inverting and non-inverting operation and therefore,can compensate both voltage sags and swells. A detailed analysis of the proposed DVR is given,followed by the experimental results. |
