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[on:]

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???

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!!!

[Reply #1 on:]

Read this:
http://hekilledmywire.wordpress.com/2011/08/03/introduction-to-pwm-part-7/

[Reply #2 on:]

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

thanks

[Reply #3 on:]

Code:

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:

Code:

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?

[Reply #4 on:]

Check this out, too:  http://www.arduino.cc/playground/Code/PwmFrequency
Tops out at 65kHz before you get deeper into the various timer registers.

[Reply #5 on:]

Code:

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

Think of your calculations like this:

Code:

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

[Reply #6 on:]

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!!

[Reply #7 on:]

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.