Help me to setup the PWM frequency to 10khz

Other Hardware General Electronics
1

I am working on a project of a converter for Photovoltaic modules and
I am using an Arduino Uno board to generate a PWM to controll a IGBT.
I need at least 10khz frequency pwm and using analogWrite i get 490 hz.

Can you help me configuring the timers to have a 10khz frequency??? :grin:

here is the code:

/*

  • Two Stage Single Phase Inverter control
  • JN. Barbosa - MERCEUS - DEE - FCT-UNL
    */

int Vpv0 = 0; // inicials conditions
int Ipv0 = 0;
int P0 = 0;
int Vpv1 = 0;
int Ipv1 = 0;
int P1 = 0;
int D = 0.500; // duty-cycle
int dD = 0.001; // perturbation

void setup()
{
pinMode(3, OUTPUT); // sets the pin as output
}

void loop()
{
Vpv0 = analogRead(A1); // read the pv voltage
Ipv0 = analogRead(A2); // read the pv current
P0 = Vpv0*Ipv0; // calculate instant power

delay(1);
Vpv1 = analogRead(A1);
Ipv1 = analogRead(A2);
P1 = Vpv1*Ipv1;

int dV = Vpv1-Vpv0;
int dP = P1-P0;

if (dP > 0){
if (dV > 0){
D = D+dD;
}else{
D = D-dD;
}
}else {
if (dV > 0){
D = D-dD;
}else{
D = D+dD;
}
}

analogWrite(pwmPin,D*255);
}

Thank you a lot!!!

2

Read this:

3

thank you for the reply Senso!!
the text is long but i will read it all.

thanks :grin:

4 
 int D = 0.500; // duty-cycle
 int dD = 0.001; // perturbation

This isn't going to work. An integer is a whole number, without a fractional or decimal part. Maybe you meant:

 float D = 0.500; // duty-cycle
 float dD = 0.001; // perturbation

But, remember that 'float' variables and calculations are much slower than 'int's. Could you scale all your calculations to use integers, say in the range of 0..1023 or 0..255?

5

Check this out, too: Arduino Playground - PwmFrequency
Tops out at 65kHz before you get deeper into the various timer registers.

6 
int D = 0.500; // duty-cycle
 int dD = 0.001; // perturbation

Think of your calculations like this:

int D = 0; // duty-cycle
 int dD = 0; // perturbation
7

hello guys!!
Anachrocomputer, you are right. I shall use float numbers for dutycycle and perturbation.

AWOL, the perturbation must be greater than zero.

Thank you!! :grin:

8

AWOL, the perturbation must be greater than zero.

So don't assign a sub-unity value to an integer - it will be truncated to zero.

9

Hi, I'm kind of lost at the moment. Could you please post the code to generate the 10 kHz that worked for you?

10

int P0 = Vpv0*Ipv0;

10-bit value * 10-bit value won't fit into an int.