Study on output characteristic of bi-direction current source converters

Among the control algorithms of current source pulse-width modulation converter, space vector pulse width modulation (SVPWM) is widely applied for its higher current utilisation factor than sine pulse width modulation (SPWM). However, when the two control methods are applied to active inverters (grid-connected photovoltaic system and current source active power filter (APF) for example), they present a wholly opposite characteristic. The output characteristics are analysed and contrasted in detail between SPWM and SVPWM current source inverters. The whole work is based on energy transfer, area equivalent theorem and different mechanism of the two algorithms when trigger pulses are produced according to the current command. The conclusion is drawn that at the same running condition in inverting operation, SPWM can output higher inverting current than SVPWM. The simulation and test results are presented and a new way of bi-direction current source inverter to obtain higher current utilisation factor is presented.