Research on vector control method of neutral-point-clamped(NPC) three-level inverter with bootstrap driver

Diode neutral-point-clamped(NPC) three-level inverter has more significant characteristics than traditional two-level inverter, such as high utilization rate on voltage of the DC side, low harmonics output, small switching stress etc. There has no mature products of three-level inverter with control system until now. The bootstrap driver circuit is adopted to reduce the number of the power supply in three-level inverter to make system compact, lighter weight and low cost. The SVPWM scheme with voltage vector compensation method based on DSP F28335 is proposed to balance neural-point voltage of DC side. The experiment results indicate that the output voltage and frequency can be adjusted consecutively, waveforms of three phase voltage are symmetric. The designed NPC three-level inverter can be applied in the field of variable frequency speed regulation of motor, active power filter and electrified railway, etc.