| Summary: | 博士 === 國立成功大學 === 電機工程研究所 === 83 === This dissertation presents a new method, termed as the
synchronous detection method, for active power filter to
compensate the reactive and harmonic current in an unbalanced
three-phase power system. Although the instantaneous power
theory is powerful to operate an active filter, an assumption
of balanced three-phase source voltage is required. Due to
the inherent unbalanced characteristics in distribution feeder
system , the synchronous detection method is proposed here to
handle the unbalanced voltage to solve the reactive and
harmonic current compensation problem. Three alternative
methods using equal power , equal line current and equal
resistance concept of the synchronous detection method are
formulated. By simulation results, the performance of the
synchronous detection method is proven to be improved. In this
dissertation, results using the equal power, equal line
current and equal resistance synchronous detection methods are
shown. The d-q compensated component of instantaneous power
theory is modified and reformulated for an unbalanced system ,
and its result is proven to be the same as that of equal
resistance synchronous detection method. The formula of
synchronous detection method can also be extended to multi-
phase systems, such as four-system and six-phase system.
System implementation using actual harmonic loads is also
presented, as well as the test results. The merits of the
proposed method are its capability to operate under unbalanced
system by per-phase calculation, to avoid conversion error
by force waveform calculation, and to implement in very simple
manners. This dissertation has accomplished an active
filter design for current compensation and load balancing in
an unbalanced three-phase system.
|
|---|
