Motor control (direction and PWM): H-bridge by MOSFET IRF3205

[saidi.tarik]

Hello everyone,

I've made an H-bridge with 4 Mosfet transistors (type IRF3205) for controlling a DC Motor (29 V) both: direction as well as the speed (PWM) by using Raspberry Pi board. please see below the circuit.

The Problem is that motor generate noise , could someone propose for me a solution about that ? Also if there is any rectification on the scheme.
What is the best frequency of PWM that could reduce the noise ?
Is this type of Mosfet transistor reliable for this app (especially I've a load of about 150 Kg in this app) ?
All the best

 

[Pommie]

How are you driving the gates?

PWM should be above 25k to prevent audible noise.

Mike.

 

[MaxHeadRoom78]

Picmicro suggest 5Khz and above, I have used 5.5Khz with no audible noise.
Max.

 

[ronsimpson]

Several problems:
In your circuit simulation it appears that your PWM is 0/5V. Can you get 5V out of your computer?
Next look at what the MOSFET does with only 4.5 to 5V on the gate. It barely turns on. You need more like 10V to turn on the bottom two MOSFETs.

Next the top two MOSFETS are never going to turn on with only 5V of the Gate. You need to drive the Gates to 29+10=39volts.
Also keep in mind that the Gate to Source voltage should never get more than +/- 20 volts.