• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

AC output wave distorted

Status
Not open for further replies.
Hello. I am working on a 3 phase inverter. I have generated 6 SPWM. But output waves don't always seem like sinewave. I have connected three transformers ( delta ) to three IGBT modules. Output is taken with neutral common ( star connection ) and filtered using 10 MFD ( big! ) caps.
 
I don't have simulator but this rough diagram could help. Boxes near the IGBTs represent isolated gate drivers. The numbers near them represent their switching sequence. SPWM signals are taken from a microcontroller. And the transformer windings are connected to IGBTs ( delta connection). The output is taken as a star connection with common neutral. And the caps connected between each phase and neutral. Tell me if I'm missing something else!
 

alec_t

Well-Known Member
Most Helpful Member
..... and we're still waiting for further details. Block diagrams aren't enough for dignosing your 'problem'. A full schematic (even hand sketched) clearly showing component values would be helpful.
 
There's nearly nothing between the IGBTs and the PIC microcontroller except the ISOLATED GATE DRIVERS- which are completely fine. If they would have problems why I would get sinewaves as shown in the pics above?
 

alec_t

Well-Known Member
Most Helpful Member
Perhaps the windings of your transformers (properties unknown) are saturating at parts of the sine cycle when you draw significant load current.
 
The transformers and IGBTs are taken from a 6 KVA old inverter. I also want to load it with 6 KVA. For now the load given is 200 W X 3 bulbs.
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top