如何使用LM35和电阻进行PI控制

Question

我想通过使用带有 PI 控制器的 Mosfet 驱动器将电阻器温度保持在 45C。 我有两种方法，但我不知道哪一种是正确的？你能帮我这个吗？

#define lm35_Pin A0
#define PWM_pin  9
#define reference_temperature 45.0

double kp = 50.0;       
double ki = 0.1;        
float temp_voltage = 0.0, temperature = 0.0;
double error,pwm_output, P_Term , I_Term, lastError = 0 , integral = 0;

void setup() {
  Serial.begin(9600);
  pinMode(PWM_pin, OUTPUT);
}

void loop() {
  double inputData = analogRead(lm35_Pin);  
  temp_voltage = (inputData / 1023.0)*5000;
  temperature = temp_voltage /10.0;
  error = reference_temperature - temperature;
  METHOD 1
  P_Term =   ki * error;
  I_Term +=  kp * error;
  if (I_Term <0)  I_Term = 0;
  if (I_Term > 255)  I_Term = 255;
  pwm_output = P_Term + I_Term;
  METHOD 2
  P_Term =   ki * error;
  integral += error;
  I_Term = ki * integral;
  if (integral <0)  integral = 0;
  if (integral > 255)  integral = 255;
  pwm_output = P_Term + I_Term;

  if (pwm_output < 0) pwm_output = 0;
  if (pwm_output > 255) pwm_output = 255;

  analogWrite(PWM_pin, pwm_output);

  Serial.print("Temp: ");
  Serial.print(temperature);
  Serial.print("C  PWM: ");
  Serial.print(pwm_output);
  Serial.print(" PWM Ratio ");
  Serial.println((100*pwm_output)/255);

    delay(100); //(fs=10 Hz)
}

你能帮助我通过 PI Control 来提高自己吗？

Answer 1

您可以尝试以下代码：

#define lm35_Pin A0
#define PWM_pin  9
#define reference_temperature 45.0

double kp = 50.0;       
double ki = 0.1;        
float temp_voltage = 0.0, temperature = 0.0;
double error, pwm_output, P_Term, I_Term, lastError = 0, integral = 0;

void setup() {
  //Serial.begin(9600);
  pinMode(PWM_pin, OUTPUT);
}

void loop() {
  double inputData = analogRead(lm35_Pin);  
  temp_voltage = (inputData / 1023.0) * 5000;
  temperature = temp_voltage / 10.0;
  error = reference_temperature - temperature;

  // METHOD 1
  // P_Term is proportional to the error, and I_Term is the integral of the error
  P_Term = kp * error;
  I_Term += ki * error;

  // Ensure I_Term is within limits
  if (I_Term < 0) I_Term = 0;
  if (I_Term > 255) I_Term = 255;

  pwm_output = P_Term + I_Term;

  // METHOD 2
  // P_Term is proportional to the error, and I_Term is the integral of the error
  P_Term = kp * error;
  integral += error;  // Fix: Accumulate error in the integral term
  I_Term = ki * integral;

  // Ensure I_Term is within limits
  if (integral < 0) integral = 0;
  if (integral > 255) integral = 255;

  pwm_output = P_Term + I_Term;

  // Ensure pwm_output is within limits
  if (pwm_output < 0) pwm_output = 0;
  if (pwm_output > 255) pwm_output = 255;

  analogWrite(PWM_pin, pwm_output);

  Serial.print("Temp: ");
  Serial.print(temperature);
  Serial.print("C  PWM: ");
  Serial.print(pwm_output);
  Serial.print(" PWM Ratio ");
  Serial.println((100 * pwm_output) / 255);

  delay(100); // (fs = 10 Hz)
}