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Unity‐power‐factor PWM converter with DC ripple compensation
Author(s) -
Shimizu Toshihisa,
Fujita Tsutomu,
Kimura Gunji,
Hirose Jun
Publication year - 1998
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/(sici)1520-6416(19980415)123:1<51::aid-eej7>3.0.co;2-n
Subject(s) - ripple , electrical engineering , pulse width modulation , harmonics , power factor , capacitor , engineering , electronic engineering , voltage , control theory (sociology) , computer science , control (management) , artificial intelligence
The generation of harmonics and their subsequent propagation into power lines is a topic of increasing concern to power‐supply authorities. To prevent obstacles in the power system, a unity‐power‐factor PWM converter will be applied at ac‐dc power conversion plants. However, the PWM converter, especially at single‐phase circuit, has some serious defects, including low‐frequency ripple current that flows into the dc line and gives rise to a low‐frequency ripple voltage that appears on the dc output. In usual cases, it is necessary to connect a very large capacitor or a passive L‐C resonant circuit to the dc line for reduction of low‐frequency ripple voltage. However, when batteries are connected to the dc output, most of the dc ripple current flows into the battery even if the above circuits are used, because the impedance of the battery is very low compared to that of the circuits. The low‐frequency ripple current causes power loss on the battery and the temperature rises. It is well known that the life of a battery is deeply influenced by the temperature. The ripple current, therefore, should be reduced as low as possible. To accomplish reduction of the low‐frequency ripple current, a novel topology for the PWM rectifier is presented in this paper. The main circuit is constituted by adding only a pair of switching devices to the conventional PWM converter circuit. With a simple control technique, the ripple energy on the dc line is converted into stored energy on the input ac capacitors through additional switches. The theoretical characteristics are obtained by using the state‐space averaging method. The effect of ripple reduction is confirmed by experiments using a breadboard setup. © 1998 Scripta Technica, Electr Eng Jpn, 123(1): 51–62, 1998