1. The technology of 12 pulse rectifier is mature and reliable while the cost is higher. It needs to add a rectifier module and a phase-shifting isolation transformer.

2. When cooperating with the 11 times harmonic wave filter, the input power factor is 0.95, harmonic content of input current is about 5%, and causes smaller disturbance to electric net.

1. IGBT rectifier is using IGBT to replace SCR of the original rectifier device.

2. To add a step-up transformer with higher cost, more complicated circuit control, and higher environmental requirements.

3. The technology remains to be improved, it can only be used under 120KVA at present.

4. The input power factor can reach 0.99, with harmonic content of input current is about 5%, and causes smaller disturbance to electric net.