hi k,
Your Inductive load currents are exceeding the d/s rated values

I would suggest as a comparison test that you configure your LTS asc circuit to match the example given in the d/s.
Post when ready and we can compare.

This test circuit has an inductive load, also note the Vboot lower value capacitor.
Also use a PWM frequency as shown in the d/s.

E
View attachment 338082

Shortly hand the .asc file with the replicated circuit.

I notice though one thing in this picture ... the output current generator.
Maybe this is the answer to my question?
That is, to avoid huge values, I put an output current generator of value open to the Imax absorbed by the load.
What do you think?

Thanks

 

hi k,
Your Inductive load currents are exceeding the d/s rated values

I would suggest as a comparison test that you configure your LTS asc circuit to match the example given in the d/s.
Post when ready and we can compare.

This test circuit has an inductive load, also note the Vboot lower value capacitor.
Also use a PWM frequency as shown in the d/s.

E
View attachment 338082

 

Hi k,
Using your LTS asc ,this is what I see.
E

 

Hi k89,
Just noticed you did not have the fixed 5A load on your sim Vsw output.?
E

Update: with 5A load.

 

Hi k89,
Just noticed you did not have the fixed 5A load on your sim Vsw output.?
E

Update: with 5A load.
View attachment 338101

Okey, now we have a comparison test between LTS asc circuit and the example given in the d/s.
But how do I solve the overcurrent problem in the circuit with the gate driver? (post #59)

 

Hi k89,
Just noticed you did not have the fixed 5A load on your sim Vsw output.?
E

Update: with 5A load.
View attachment 338101

For example, I was able to reduce the output I to a "normal" value by changing the load.
However, my motor does not have these parameters ... so I am simulating something that is not my case.

 

However, my motor does not have these parameters

hi k89,
What is the specification of your motor, do you have datasheet?
E

 

hi k89,
What is the specification of your motor, do you have datasheet?
E

I only know R = 0.022 and L = 46uH.

Eventually in the circuit with the EPC2152 I was able to get within the limits of the device by decreasing the duty cycle to 1%:


However, this does not happen for example for another gate driver (LTC7061):
This is not "fully integrated" (like the EPC2152) so two external mosfets are needed.


I still have doubts about the simulations...

 

Hi k,
Your limit of 1% will not give you any control over the motor speed.
It is suggesting that EPC2152 is not suitable for your motor, using the R = 0.022 and L = 46uH. Values.
What exactly is the motor going to drive?

Are you considering the LTC7061 option, also what power supply do you have for these high voltages and currents?

E

 

hi k,
This is what I see using your posted files???
Have you modified the circuit after your simulation run?

E

 

hi k,
This is what I see using your posted files???
Have you modified the circuit after your simulation run?

E
View attachment 338176

I have not changed anything

 

Hi k,
Your limit of 1% will not give you any control over the motor speed.
It is suggesting that EPC2152 is not suitable for your motor, using the R = 0.022 and L = 46uH. Values.
What exactly is the motor going to drive?

Are you considering the LTC7061 option, also what power supply do you have for these high voltages and currents?

E

The motor (48V, 1kW) does not have to drive anything because I am only interested in simulating the behavior of the gate drivers on one phase of it, and I took as motor specifications what I have at home. By the way R and L were estimated with Texas instrument software and I do not consider it reliable, but that is another matter.

As far as GaN is concerned I found EPC2152 as a goog candidate, but as far as silicon is concerned I could not find (with similar specifications) any gate driver that has already "integrated" also mosfets (as in the casei of EPC2152) .. so I took for example LTC7061.

Therefore I fixed on both the motor resistance and inductance and ran the simulations.

I would like to actually verify in simulation that silicon, as frequency increases, starts to have lower efficiency than GaN

 

hi k,
This is what I see using your posted files???
Have you modified the circuit after your simulation run?

E
View attachment 338176

I found the problem ... they have to be reversed botin with topin in the LT7061 file.

 

Beyond the whole introduction I made about the project, etc., the question is purely mathematical:
over what interval should I integrate for each frequency?

---------------------------------------------------------LTSpice .asc file------------------------------------------------------------------------------


To determine the interval for integration for each frequency, it depends on the nature of the problem:

1. For a Continuous Signal: Integrate over one period of the frequency. If the frequency is fff, the period is T=1fT = \frac{1}{f}T=f1, so the interval is [0,T][0, T][0,T].
2. For Multiple Frequencies: Use the least common multiple (LCM) of all periods to cover a complete cycle where all signals align.
3. If It’s Fourier Analysis: Integrate over the interval [−π,π][-\pi, \pi][−π,π] or any symmetric interval of length 2π2\pi2π for each frequency component.

Let me know more details if you need further clarification!

Download the model here Spice

 

hi k,
I suspect you have the incorrect details for that motor.
This is a sim with Duty cycle D at 50%
The current in the motor is excessive.
E

 

hi k,
I suspect you have the incorrect details for that motor.
This is a sim with Duty cycle D at 50%
The current in the motor is excessive.
E
View attachment 338177

I suspect that too.

Finally I tried to simulate with the parameters of the Teknic M-2310P-LN-04K synchronous motor: Rs = 0.363 Ω, Ls = 160 µH, Imax = 7 Arms to be sure of a real, existing load.

With duty cycle of 50% the Iout = 64A ... which is obviously too much for the driver

At this point I do not understand, how do I analyze the behavior of the driver if I get these currents despite the fact that I am using a motor that exists. As soon as I increase the Duty Cycle a little bit, the currents are huge.
I don't understand how to proceed in these cases.

 

hi k89,
The results you get with a passive motor equivalent in LTSpice, will not be the same as using an actual dynamic motor load.
Check out this link and other DC motor dynamics
E


https://circuitglobe.com/what-is-back-emf-in-dc-motor.html

 

hi k89,
The results you get with a passive motor equivalent in LTSpice, will not be the same as using an actual dynamic motor load.
Check out this link and other DC motor dynamics
E


https://circuitglobe.com/what-is-back-emf-in-dc-motor.html

I agree, however, it seems strange to me that, for example, I cannot set a threshold (clamp) to the power supply generator in order to prevent it from delivering unrealistic hundreds of amps.

If I wanted to simulate on LTSpice a 48V and 10A battery, how would I do it?
How do I set the current limit?
Maybe on with "if" statement?

 

hi,
You could try this SLA sim.
Unzip the files.

sc = state of charge 0 > 1
nc =number of 2V cells.
E

 

Hi k,
You can control the battery Ahr capacity using this change.
E