MOTORWARE: space vector generation star point shifting

Benjamin Prescher2

Part Number: MOTORWARE

Hello. I keep seeing that the space vector generation is generated around DC Link / 2. What effects would be expected if the (in this case isolated) star point were permanently shifted? When I search for it, I keep coming across the keyword "common mode voltage", but I still cannot conclusively understand the effects when dealing with an isolated star point.

I am very grateful for brief feedback from an expert.

over 4 years ago

0 Yanming Luo over 4 years ago

TI__Guru** 116090 points

You might have a look at the application note which has a detailed description of SVPWM, or you can find more details about SVPWM in motor control textbooks.

Space-Vector PWM With TMS320C24x/F24x Using Hardware and Software Determined Switching Patterns (SPRA524)

0 Benjamin Prescher2 over 4 years ago in reply to Yanming Luo

Prodigy 40 points

Thank you for the feedback. I am aware of various literature that describes the generation of space vectors, but unfortunately I do not find any information about a permanent shift in the generation from the center (center means DC Link / 2). In the typical case, all FETs switch at 50% when the motor is at a standstill and thus brings the star point of the 3-phase system to DC Link / 2. My question therefore has more of a theoretical background as to whether negative effects would be expected in the event of a permanent displacement from the center (DC Link / 2). In this case, should capacitive equalizing currents be expected (assuming an isolated star Point )? Something like that? Thanks!

0 Yanming Luo over 4 years ago in reply to Benjamin Prescher2

TI__Guru** 116090 points

No, you don't need to worry about that if you are using a two-level three-phase inverter with SVPWM. The SVPWM is just an algorithm that is not related to the dc-bus and the half of the dc-link.

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MOTORWARE: space vector generation star point shifting