ABSTRACT
Matrix Converter (MC) has many advantages such as simple topology, bi-
directional power flowing, adjustable input power factor, etc. Therefore, MC research
has become a hot topic in power conversion technology in recent years. However,
conventional Matrix converter has complex control strategy and commutation problems,
which makes MC difficult to be widely used. Two-stage matrix converter (TSMC) is a
new type of matrix converter, which is developed on the basis of CMC. TSMC
becoming the mainstream of MC research because it not only have the same
performances as CMC, but also overcome the problem of the complex commutation of
CMC, and for the input stage the soft switching is realized.
In this thesis, with an improved two-stage topology, a new type of five-phase two-
stage matrix converter is presented, for which a three phase to five-phase direct power
conversion can be complemented.
Five-phase TSMC has the same advantages as three-phase TSMC, such as less
switches, more convenient commutation, simpler commutation and control strategy, etc.
In addition, the matrix converter presented in this thesis is mainly used in five-phase
induction machine drive system. Compared with three-phase induction machine drive
system, multi-phase induction machine drive system has advantage of being operated at
phase opening. Compared with three-phase TSMC, five-phase TSMC has much smaller
high frequency input current ripple, thus eliminating the need to use more three-phase
loads to decrease TSMC current ripple.
Chapter one mainly discusses the recent progress of matrix converter research, the
purpose and direction of this search; chapter two introduces three-phase MC research
progress and several main control algorithms, at the same time three-phase space vector
modulation method is described in detail; in chapter three deep investigation on five-
phase TSMC has been completed, and with the improved five-phase park conversion,
five-phase space vector modulation technology has been developed, and simulations are
proceeded to verify various control strategies.
In reality, the power grid voltages are always unbalanced. Chapter four analyzes
the influence of unbalanced power grid voltages on the five-phase TSMC, and proposes
the improved method. At first, the mathematical model of five-phase TSMC space
vector modulation is established, and then the influence of negative sequence voltages
on output voltages and input currents has been analyzed. Finally, the method which may
eliminate the second order harmonic in output voltages and input currents is proposed.
In order to make five-phase TSMC operate better and more stable, chapter five