Based on the brief introduction about five-phase H-bridge three-level inverter, the static behavior of it was given with the presentation of switching characteristic on reverse conducting intergrated gate commutated thyristors (IGCT) and phase shifting space vector modulation.

As for the five-phase three-level H-bridge inverter,the number of its output voltage vectors is so large that it\'s hard to apply the traditional SVPWM algorithm method into use.

Application of Inverter Based on Capacitor-clamped 5-level H-bridge;

Application of a Diode-clamped 5-level H-bridge Inverter;

In the view that the capacity of APF with single PWM converter is limited, the dissertation designs a voltage source high power active power filter by using 9-level cascade H-bridge convertor as main circuit,a improved i_p-i_q measurement method as instruction current calculation strategy and CPS-SPWM technology as current tracking control strategy,aiming at enlarging the capacity up to 1MVA.