Space Vector PWM Labview (3-ph)

[jackferz]

Hi  All,

I have a simple concept of Triangular Reference PWM. The program is simple in labview rather in Matlab Simulink.

I need someone to help me if i want to plot SPACE VECTOR PWM. The attached VI  is just a reference for you.

How would the math be if i want to plot Voltage reference as a vector.

thanks

[jackferz]

is plotting vectors in labview possible.

How to do mathematics for matrices for plotting vectors.

any references would be appreciated

[Julianne_K]

Hi jackferz, 

I would suggest using a compass plot to plot a vector. This allows you to specify a magnitude and an angle as inputs to the graph. Please let me know if this works for your application and best of luck. Sincerely, 

Julianne K 

[jackferz]

Julianne,

Thanks for the reply. I was able to find a vi for compass plot but is there any thing related to Space Vector that has already been tried using compass plot in labview?

Any examples related to this, any links?

[Julianne_K]

Hi jackferz, 

I haven't been able to find examples of plotting a space vector. However, are you able to paste a picture of what you are trying to do and perhaps I can help you based on that? Thanks, 

Julianne K

[jackferz]

Julianne

Yes, i have attached some work what u suggested to do in Compass plot. But just to give you basic idea of what i need, attahced is the .png to show you three phase transformation of A, B anc C.

Is it possible to program the something like that in labview. I want to plot three phase and then do the projection(transformation) for it in the hexagon space vector.

Something similar to this.

[Julianne_K]

Hi jackferz, 

Great work with the compass plot! I'm not sure if I understand you correctly, but I think you are trying to generate a reference from three separate phases which would require using the alpha beta transform. You can do all this math using the matrix functions in LabVIEW.

If you right click on your block diagram, and go to Mathematics -> Linear Algebra, you will find all the tools for building and completing matrix operations. You can also refer to the examples "Linear Algebra Calculator" and "Matrix Fundamentals" by going to Help --> Find Examples.

Then you can feed the result of your matrix operations into your compass plot program. Will that help with your application? Best of luck, 

Julianne K

[jackferz]

julianne

Alpha -Beta trnsfomation is exactly what i need so far and definitely it would require some matrices function but i was completely not sure if it was possible using labview.
However i will try to work my way through the examples u have suggested.

Will get back soon to you

manyu thanks 

[jackferz]

Julianne,

I didnot follow the matrices function for abc to Alpha beta transformation. however i have performed equation with labview basic arithmetic vis .

Attached

But the compass plot does not relate with waveform chart timing. How to plot (wt =360rad) on x axis of waveform chart and compass plot.

Secondly, the alpha beta projections are only on x axis.

Thanks

[Julianne_K]

Hi jackferz, 

If you want to make the x-axis a function of frequency, you can modify a property of the waveform graph called the multiplier. To axis this property, right click on the graph, go to "X Scale", then select "Properties". Under the "Scales" tab, there is an option under the "Scaling Factors" heading to change the multiplier. Here you can enter your frequency value. If you want to do this dynamically in your block diagram you can use a property node. To create a property node for the multiplier property, right click on the waveform graph in the block diagram, then go to Create -> Property Node -> X Scale -> Offset and Multiplier -> Multiplier. After you have put this on your block diagram, you can right click on the property node and select "Change to Write" and then you can wire a frequency control to the property node. Does this accomplish what you were aiming to do?

Also, I believe that the alpha beta projection should give you two directions. Perhaps you should try the matrix method?

Hope this helps! Sincerely,