Please help . Mosfets - delay signal problem

Thread Starter

Mit Dac

Joined Jun 5, 2019
11
Hello everyone, I am newbie , I have problem with my circuits. i try to make H bright to control motor. I using arduino uno to control PWM signal. this is problempic 1.PNG

pic 2 .PNG
i write code for arduino , i make pwm signal and use low pass filter to make it to Sin wave . Problem is : when i use controller of mosfet ,it makes delay in my signal , i know mosfet and controllers make delay but according to data sheet of TC 4223 my signal cant be delay that much , i dont know why , my Sin Wave signal is only 200hz at max speed . And voltage drop is alot.
i used only 5Mhz in arduino and PWM from arduino is ‭19.531 hz 8bit timer.
this is a circuits when i added controller.


I am not an electrical engineering student , Could you please explain my problem in simple ways ( all i learned from youtube and MIT) . Please help .
Thank you so much

Ps: sorry about my bad English.
 

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Bordodynov

Joined May 20, 2015
2,383
I understand that you don't have enough voltage to control the upper transistors. This results in a very low voltage on the motor.
 

Thread Starter

Mit Dac

Joined Jun 5, 2019
11
@danadak , Bordodynov : Thank you so much to replay my question. i am sorry about my lack knowledge about circuits.


in my real circuits i will supply TC4423 with 12 v DC.
http://ww1.microchip.com/downloads/en/DeviceDoc/21421E.pdf
problem in my proteus 8 . it dont not show any simulation of TC4423 with 8 pin like data sheet. i only find this version of TC 4423 so maybe simulation in Proteus is not correct.
the first picture is 5 v supply from arduino uno


pic 1. 1.png

the second is 12v DC supply

pic 2.2  .png
i try to fix problem as you said about inductance suppression,
3 .PNG
but i dont see its working . Could you suggest or give me correct circuit. it will be great.
Thank you so much
 

Thread Starter

Mit Dac

Joined Jun 5, 2019
11
My target is circuits to control AC motor so i need make Sin from PWM sign. this is one of 3 phase in ac motor. I know what i am doing more than my knowledge. Could you please help. i really want to do this project.
I can write arduino code for 3 phase and it works but circuits to control motor i dont know.
Please help
 

Bordodynov

Joined May 20, 2015
2,383
To control the upper transistors, at least 19 volts are required (this is the minimum required control voltage, preferably 22 volts). There are special drivers to control the upper transistor.
 

ScottWang

Joined Aug 23, 2012
6,817
When you using the N MOSFET as a high side driver then the Vg1 and Vg2 need to increase more voltage as
Vg1 = Vcc+Vgs1 = Vcc+3V,
Vg2 = Vcc+Vgs2 = Vcc+3V,
Because the high side Vgs needs about 3V.
 

BobTPH

Joined Jun 5, 2013
2,017
In addition to what others have said about what you need to switch the upper MOSFETs:

You do not send a sine signal into the H bridge. An H-bridge should be switched only by square waves. To make a sine-like output, you vary the duty cycle of the PWM to match the amplitude of the sine wave. You need to do some research on this, as you really don't understand it.

Bob
 

Thread Starter

Mit Dac

Joined Jun 5, 2019
11
4.PNG
this is out put signal half sin wave i generate from arduino . i use H bright to change half direct of sin way.this is i am doing , but in my H bright have problem
5 .PNG
Can someone help me with my H bright
i can make 3 phase sin wave
6 .PNG
this 3 half sin wave with 120 degree change . I just need H bright to make it become Sin wave. Please help
 

BobTPH

Joined Jun 5, 2013
2,017
You need a linear amplifier to do what you are trying to do, not an H-bridge.

And that is the wrong way to do it anyway, since it will waste at least 50% of the power in heating of the transistors. It is like the difference between a class AB and a class D audio amplifier. The class D audio amplifier is an H-bridge, but it uses the modulation of the PWM duty cycle + filtering to duplicate the input waveform.

Read the paper linked by Dana. This is what you need to do to get a sine out of an H-bridge. It is not a simple concept that can be taught in a forum post.

Bob
 

Thread Starter

Mit Dac

Joined Jun 5, 2019
11
@BobTPH : thank you so much to reply me. I think you dont understand what i said . i know how to match the amplitude of the sine wave by change my code in arduino i can make it match exactly what i want and i know problem when use transistors, what i dont know is how to make good H-bridge circuits and decrease delay signal .
 

BobTPH

Joined Jun 5, 2013
2,017
No, I understand exactly what you are trying to do. And I know that it is incorrect by looking at your scope traces.

Take out the low pass filter and you will have the correct signal to sebd to the H-bridge. Except that you need gate drivers to adjust the levels needed by the high side MOSFETs.

Bob
 

Thread Starter

Mit Dac

Joined Jun 5, 2019
11
@: BobTPH : thank you alot, i will take out low pass filter , can i ask question ? is it possible to create sin wave true form not PWM sign from H-bridge ? Could you give me a name or some document in detail, it will be awesome .
Thank you alot
 

Thread Starter

Mit Dac

Joined Jun 5, 2019
11
@:Bordodynov : thank you so much Sir .
i have a question , If i use signal like a picture below : PWM + filter to H-bridge like Bordodynov's example . Can i get full sin wave signal ?
7.PNG
 

Alec_t

Joined Sep 17, 2013
10,354
No. You apply PWM to the bridge and (if necessary) filter the bridge output. If the bridge load is a motor then the motor windings provide the filtering.
 

Thread Starter

Mit Dac

Joined Jun 5, 2019
11
@: Alec_t : Thank you alot
this is what i understand , the winding in motor itself is inductor so its filtering signal , so signal i get in Current form is Sin wave but Voltage is PWM , am i correct ?
i find this one in youtube.
I am sorry, i am newbie :D
 
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