onventional SVM method, and the
fourth lec, can be controlled by the principle that the mean values of neutral point voltage
of the output in three-leg three-phase inverter and four-leg three-phase inverter are equal in
one switch period.
Some applications of three-phase inverter has a control structure comprising, an
internal current feedback loop. Consequently, the performance of the converter system
largely depends on the quality of the applied current control strategy. The main task of the
control scheme in a current control inverter is to force the currents in a three-phase ac load
to follow the reference signals. By comparing, the command and measured instantaneous
values of the phase currents, the current controller generates the switching states for the
inverter power devices which decrease the current errors. Hence, in general, the current
controller implements two tasks: error compensation and modulation. The property of
internal current feedback loop has been analyzed. Two methods to generate the switching
states for the fourth leg are proposed, and the previously presented control strategy of the
other three leas can still be available. By using current control, a lot of advantages can be
achieved, such as control of instantaneous current waveform and high accuracy, peak
current protection, extremely good dynamics, etc.
key words: three-leg; four-leg; three-phase inverter; pulse-width modulation
space vector modulation; current control
II
南京航空航天大学博士学位论文
目录
第一章绪论·................................................................................................................. 1
1.1三相逆变器的一般结构及其控制方案********************************************************......1
1.2三相逆变器的其它结构·.................................