How can I generate two phase-shifted PWM signals using Dspace DS1104

Thread Starter

Houhou Alaoui

Joined Nov 4, 2017
5
Hello everyone,
I'm trying to design and control a dc-dc multilevel boost converter, so I've to generate two phase-shifted PWM signal in order to control the MOSFETs used in this converter; in my case I'm using Dspace DS1104 for this purpose but I can't create the phase shifting.
I really need your help.
 

Thread Starter

Houhou Alaoui

Joined Nov 4, 2017
5
Hello everyone :),
I'm trying to design and control a dc-dc threelevel boost converter, so I've to generate two phase-shifted PWM signals in order to control the MOSFETs used in this converter; in my case I'm using Dspace DS1104 for this purpose but I don't know which blocs I've to use to generate such signals. The converter that used is presented bellow.
I really need your help and thank u in advance.
 

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Thread Starter

Houhou Alaoui

Joined Nov 4, 2017
5
Thank u crutschow & Alec_t, It is a good solution to add a delay circuit , I agree it gonna work but I look for generating PWMs using Dspace and directly link them to the converter control circuit without adding an other circuit . I hope understanding me and finding a solution for my issue
 

danadak

Joined Mar 10, 2018
4,057
The board has a TMS320F240 which has the timer/pwm capability.

Along with this is a compare unit which has dead band capability which
can effect phase shifting. I do not know, w/o further examination, if the
dead band logic will permit phase shift of an entire pulse or can only
implement dead band, which phase shifts each pulse edge. You would
have to read manual on this.

Dead band allows user to create two non overlapping outputs, typically
for controlling H bridges to prevent power supply shorts in a vertical
leg of the bridge.

You could contact a TI FAE and describe the phase shifting you want,
give them a timing diagram, to see if it can handle the problem. But
Dead Band for sure it can handle.

Alternatively you can do a SW PWM and that allows you to control
everything.

TI ap note on implementing Dead Band in TMS320F240 -

http://www.ti.com/lit/an/spra289/spra289.pdf


Regards, Dana.
 
Last edited:

Thread Starter

Houhou Alaoui

Joined Nov 4, 2017
5
The board has a TMS320F240 which has the timer/pwm capability.

Along with this is a compare unit which has dead band capability which
can effect phase shifting. I do not know, w/o further examination, if the
dead band logic will permit phase shift of an entire pulse or can only
implement dead band, which phase shifts each pulse edge. You would
have to read manual on this.

Dead band allows user to create two non overlapping outputs, typically
for controlling H bridges to prevent power supply shorts in a vertical
leg of the bridge.

You could contact a TI FAE and describe the phase shifting you want,
give them a timing diagram, to see if it can handle the problem. But
Dead Band for sure it can handle.

Alternatively you can do a SW PWM and that allows you to control
everything.

TI ap note on implementing Dead Band in TMS320F240 -

http://www.ti.com/lit/an/spra289/spra289.pdf


Regards, Dana.
Thank u so much dana for your reply, I appreciate it. I will try to contact a TI FAE as you told me. More precisely, my prob is that I use the bloc that you can see bellow in the figure (it is implemented in Matlab/simulink) to generate PWMs but I like to find a solution just by using simulink blocs allowing generate two phase-shifted PWM signals.
upload_2018-11-27_9-9-8.png
 
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