Question about a control logic needed to be implemented

Thread Starter

lesdox7

Joined Apr 3, 2024
10
Hello everybody.I have to implement the in house circuit cc-ih circuit which is an energy harvester circuit using simscape electrical. The description of the circuit can be found on page 7 of the pdf at Finite element-based assessment of energy harvesting in composite beams with piezoelectric transducers:
As you can see it has a detailed analysis of it, and also its diagram. My simscape implementation so far looks like this:1712139919117.png
My question is the following. I dont know how to create the control logic so that the mosfet can be used as a switch and be turned off/on based on the threshold voltage. I ve tried using relational operator blocks combined with constant blocks to represent the trheshold voltage, ive tried the comparator block but it wont let me connect the output of the voltage sensor to the comparator block, now i am trying the relay block and it doestn seem to be working. If anyone wants to help me he needs only to read page 7-8 where my circuit (In-house PEH circuit (cc-ih) ) is described. Thanks in advance guys.
 

Ya’akov

Joined Jan 27, 2019
9,246
Hello, i am studying electrical and computer engineering and this is for my diploma thesis
OK—AAC rules require that any coursework related questions be posted to the Homework Help forum because members are constrained concerning the type and extent of help they can offer.

We are happy, where possible, to help you refine your own work, and point you in productive directions—but unlike non-academic questions complete answers using information not provided in the question are not permitted.

I have moved your thread to the Homework Help forum. Good luck with your thesis, I hope there are members who can guide you.
 

Thread Starter

lesdox7

Joined Apr 3, 2024
10
OK—AAC rules require that any coursework related questions be posted to the Homework Help forum because members are constrained concerning the type and extent of help they can offer.

We are happy, where possible, to help you refine your own work, and point you in productive directions—but unlike non-academic questions complete answers using information not provided in the question are not permitted.

I have moved your thread to the Homework Help forum. Good luck with your thesis, I hope there are members who can guide you.
Oh , sorry , i didnt know that. thanks a lot. have a nice day!
 

MrAl

Joined Jun 17, 2014
11,587
Hello everybody.I have to implement the in house circuit cc-ih circuit which is an energy harvester circuit using simscape electrical. The description of the circuit can be found on page 7 of the pdf at Finite element-based assessment of energy harvesting in composite beams with piezoelectric transducers:
As you can see it has a detailed analysis of it, and also its diagram. My simscape implementation so far looks like this:View attachment 319041
My question is the following. I dont know how to create the control logic so that the mosfet can be used as a switch and be turned off/on based on the threshold voltage. I ve tried using relational operator blocks combined with constant blocks to represent the trheshold voltage, ive tried the comparator block but it wont let me connect the output of the voltage sensor to the comparator block, now i am trying the relay block and it doestn seem to be working. If anyone wants to help me he needs only to read page 7-8 where my circuit (In-house PEH circuit (cc-ih) ) is described. Thanks in advance guys.
Hello there,

Isn't Figure 7 on page 8 telling you anything useful, or is it you just need to translate into a specific simulation environment?
 

Thread Starter

lesdox7

Joined Apr 3, 2024
10
Hello there,

Isn't Figure 7 on page 8 telling you anything useful, or is it you just need to translate into a specific simulation environment?
the circuit of figure 7 is not the one i am trying to implement, i am trying to implement the one shown in figure 5 and i am stack in that controller shown in the diagram and how to implement it
 

MrAl

Joined Jun 17, 2014
11,587
the circuit of figure 7 is not the one i am trying to implement, i am trying to implement the one shown in figure 5 and i am stack in that controller shown in the diagram and how to implement it
I took a cursory look at figures 5 and 7 and it looks like figure 7 is an implementation of the concept illustrated in figure 5. I thought that would help you understand how this might be done.

It's interesting how people are trying to extract even the smallest energy from processes that normally do not have this kind of thing built in. The side effects also have to be considered if it causes too much of a change in the physical structure.
 

Thread Starter

lesdox7

Joined Apr 3, 2024
10
I took a cursory look at figures 5 and 7 and it looks like figure 7 is an implementation of the concept illustrated in figure 5. I thought that would help you understand how this might be done.

It's interesting how people are trying to extract even the smallest energy from processes that normally do not have this kind of thing built in. The side effects also have to be considered if it causes too much of a change in the physical structure.
thanks for your replies man. am i blind and i cant see the implementation anf concept you are seeing? you mean using a schmitt trigger? sorry my level of knowledge in power electronics isnt that high
 

k1ng 1337

Joined Sep 11, 2020
986
thanks for your replies man. am i blind and i cant see the implementation anf concept you are seeing? you mean using a schmitt trigger? sorry my level of knowledge in power electronics isnt that high
Use this topic to reflect on what you know about the circuit and what you don't know. Convert the schematic to a flow chart or pseudo-code to get a different visualization of what is present in the circuit. What do you need to implement in terms of an algorithm to achieve the desired control logic?
 

MrAl

Joined Jun 17, 2014
11,587
thanks for your replies man. am i blind and i cant see the implementation anf concept you are seeing? you mean using a schmitt trigger? sorry my level of knowledge in power electronics isnt that high
Hello again,

Figure 5 indicates a basic schematic of what is required as far as the concept of how this is done, but it does not show any details. By that you can see that it is measuring what looks like the voltage across the cap, then sending that info to the controller, and the controller decides when to turn on (and off) the MOSFET.

In figure 7, they show using a Schmitt trigger to drive an IGBT which then provides power the buck circuit. The buck circuit then powers the load.

I assume you have to do this as a simulation in a simulation environment. That means you have to know how to set up the simulation for this kind of task.
For one you would have to simulate the piezo, then the diodes, then the cap, then the Schmitt trigger, then the MOSFET, then the buck circuit with a load.
You can do a rough analysis of the Schmitt trigger circuit and see how it works with the cap voltage and provides an output to the second LM324, and then how that drives the IGBT. Alternately you can probably just look up how a Schmitt trigger circuit works and figure out how to implement that in your simulation environment, then the MOSFET, then the buck with load.

I'm not sure what you have already done or how well you know your simulation environment so it's hard to say anything else about this yet.
If you do not know how to simulate things or set up the models or create models if you have to, then you are going to have to study that separately perhaps in the software you intend to use if they have a help section.
I am also not sure just how well you are supposed to do this, like how much detail do you have to include. It does look like you don't have to study the finite element details but I can't be sure about that either because I don't know who gave you this project or what they expect from you.
Maybe you can mention some other projects you worked on in the past and how they worked out overall.
Also, what kind of math you had used in the past.

In this section of the forum you are also supposed to show your best attempt first, and that not only gives you a chance to think about it fully, it also helps other members get a feel for what you are looking for as to what help you need exactly. There are many levels of detail so it's hard to judge without seeing some of your past work and success.
 

Thread Starter

lesdox7

Joined Apr 3, 2024
10
Good morning my friend, Thanks for your time again. I have indeed included my simscape implemntation in the original post, i dont know why you cant see it. I look at the options you mentioned and i ll try figure it out i guess. Thanks!
 

MrAl

Joined Jun 17, 2014
11,587
Good morning my friend, Thanks for your time again. I have indeed included my simscape implemntation in the original post, i dont know why you cant see it. I look at the options you mentioned and i ll try figure it out i guess. Thanks!
Hi,

Yes I see it, but did you try it out and did it work?
I do not actually use simscape either so I can not comment too much about the environment or the models used for that, but I would think if you got some reasonable results you must be on the right path. If not, then you have to read up on the environment rules and models and so forth.
Sorry about that, but I have not used every possible simulator tool out there (yet, ha ha).

My suggestions where to look at the analog model shown (figure 7) so you can get a feel for what was required, and if you did that already then you should be on the right track. You just need to examine your results.

You mentioned something about the Schmitt Trigger concept being maybe too vague or something. All that does is measure a quantity like the voltage, then when the voltage reaches a certain higher level the output changes state (like from low to high, or from high to low). It then stays in that state until the voltage drops to a lower level than the higher level where it changed state, then it changes back to the original state again. So it would go from one state at voltage v1, then when the voltage drops to v0 it would change back to the original state. That's how the Mosfet turns on and off. As to what levels these should be, you will have to figure that out possibly by experiment or by analyzing the sensor behavior. The sensor may have peak outputs which you would want to capture.
Analyzing the sensor would be interesting but would take some time.
 
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Thread Starter

lesdox7

Joined Apr 3, 2024
10
Hi,

Yes I see it, but did you try it out and did it work?
I do not actually use simscape either so I can not comment too much about the environment or the models used for that, but I would think if you got some reasonable results you must be on the right path. If not, then you have to read up on the environment rules and models and so forth.
Sorry about that, but I have not used every possible simulator tool out there (yet, ha ha).

My suggestions where to look at the analog model shown (figure 7) so you can get a feel for what was required, and if you did that already then you should be on the right track. You just need to examine your results.

You mentioned something about the Schmitt Trigger concept being maybe too vague or something. All that does is measure a quantity like the voltage, then when the voltage reaches a certain higher level the output changes state (like from low to high, or from high to low). It then stays in that state until the voltage drops to a lower level than the higher level where it changed state, then it changes back to the original state again. So it would go from one state at voltage v1, then when the voltage drops to v0 it would change back to the original state. That's how the Mosfet turns on and off. As to what levels these should be, you will have to figure that out possibly by experiment or by analyzing the sensor behavior. The sensor may have peak outputs which you would want to capture.
Analyzing the sensor would be interesting but would take some time.
Thank you my friend for your help!!! i am glad. when i finish this up i will come with the results. Cheers
 
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