Hey hey,
I have been working on Space Vector Modulation (SVM), a kind of pulse width 
modulation used to drive electric motors. It's in the inverters that convert a 
DC signal to an AC signal and see to it that the power is steadily increased.
https://en.wikipedia.org/wiki/Space_vector_modulation

I tried to read the article carefully. Attached is a CSD which brings two 
versions: one modelled as closely as possible to reality, one slightly 
simplified by using vco2 for the pulsewidth modulation. I'm still not entirely 
sure, I got the maths right. Perhaps one of you, who is interested and has the 
knowledge, could take a peak...

For SVM we also apparently need the alpha, beta gamma transformation:
https://en.wikipedia.org/wiki/Alpha%E2%80%93beta_transformation

Otherwise, just happy listening and plugging your fingers in your ears. :)

Best wishes,

Jeanette

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Hi Jeanette,

Thank you for sharing the motor sound. I like these kinds of machine sounds.
SVM is related to VFD(variable-frequency drive) isn't it? The attached is a primitive csd I created before to emulate VFD train motor sound.
My code simply emulates the waveform and doesn't use much mathematics.

Tetsuya Miwa


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> 2026/03/12 5:16、Jeanette C. <000015cdd0ffa6cd-dmarc-request@LISTSERV.HEANET.IE>のメール:
> 
> Hey hey,
> I have been working on Space Vector Modulation (SVM), a kind of pulse width modulation used to drive electric motors. It's in the inverters that convert a DC signal to an AC signal and see to it that the power is steadily increased.
> https://en.wikipedia.org/wiki/Space_vector_modulation
> 
> I tried to read the article carefully. Attached is a CSD which brings two versions: one modelled as closely as possible to reality, one slightly simplified by using vco2 for the pulsewidth modulation. I'm still not entirely sure, I got the maths right. Perhaps one of you, who is interested and has the knowledge, could take a peak...
> 
> For SVM we also apparently need the alpha, beta gamma transformation:
> https://en.wikipedia.org/wiki/Alpha%E2%80%93beta_transformation
> 
> Otherwise, just happy listening and plugging your fingers in your ears. :)
> 
> Best wishes,
> 
> Jeanette
> 
> --
> * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g
> * GitHub: https://github.com/jeanette-c
> 
> Csound mailing list
> Csound@listserv.heanet.ie
> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND
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Hello Tetsuya Miwa,
many thanks for sharing your code. This is great! It gives me new ideas and 
explains how a few things, that I heard, could be created.

Yes, the SVM is a system to supply a motor with power. The idea is, if I 
understand it correctly, to keep the pulse frequency constant, while the 
changing pulse width can supply the motor with anything from 0 to max voltage. 
AFAIK, even some modern trains with SVM do however change the frequency or 
run, what is known as pattern mode.

Again, many thanks for sharing. If I may, I will use your code as guidance and 
a self-teaching resource to further develope my own train sound. I will share, 
when I'm happy with it.

Best wishes,

Jeanette

Tetsuya Miwa, Mar 17 2026:

> Hi Jeanette,
>
> Thank you for sharing the motor sound. I like these kinds of machine sounds.
> SVM is related to VFD(variable-frequency drive) isn't it? The attached is a primitive csd I created before to emulate VFD train motor sound.
> My code simply emulates the waveform and doesn't use much mathematics.
>
> Tetsuya Miwa
>
>
> Csound mailing list
> Csound@listserv.heanet.ie
> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND
> Send bugs reports to
>        https://github.com/csound/csound/issues
> Discussions of bugs and features can be posted here
>

--
  * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g
  * GitHub: https://github.com/jeanette-c

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