#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <math.h> // Include math library for sin function

LiquidCrystal_I2C lcd(0x27, 20, 4); // Adjust address based on your I2C address

const int potPin = A0; // Potentiometer pin

// Define pins for PWM output to control the inverter
const int pwmPinA = 9;  // Phase A
const int pwmPinB = 10; // Phase B
const int pwmPinC = 11; // Phase C

const int motorPoles = 4; // Number of poles of the motor

void setup() {
  // Initialize serial communication for debugging
    Serial.begin(9600);

      // Initialize the LCD
        lcd.init();
          lcd.backlight();

            // Set PWM pins as outputs
              pinMode(pwmPinA, OUTPUT);
                pinMode(pwmPinB, OUTPUT);
                  pinMode(pwmPinC, OUTPUT);

                    // Display initial message
                      lcd.setCursor(0, 0);
                        lcd.print("3-Phase VFD System");
                          lcd.setCursor(0, 1);
                            lcd.print("Freq: ");
                              lcd.setCursor(0, 2);
                                lcd.print("RPM: ");
                                }

                                void loop() {
                                  // Read speed control input from potentiometer
                                    int potValue = analogRead(potPin);
                                      // Map potentiometer value to frequency range
                                        float frequency = map(potValue, 0, 1023, 0, 50); // Example: 0 to 50 Hz

                                          // Calculate RPM based on frequency
                                            float rpm = (120.0 * frequency) / motorPoles;

                                              // Generate PWM signals for 3-phase output
                                                generate3PhasePWM(frequency);

                                                  // Display frequency and RPM on LCD
                                                    lcd.setCursor(6, 1);
                                                      lcd.print(frequency);
                                                        lcd.print(" Hz   "); // Clear any extra characters

                                                          lcd.setCursor(5, 2);
                                                            lcd.print(rpm);
                                                              lcd.print("    "); // Clear any extra characters

                                                                // Print frequency and RPM for debugging
                                                                  Serial.print("Frequency: ");
                                                                    Serial.print(frequency);
                                                                      Serial.print(" Hz, RPM: ");
                                                                        Serial.println(rpm);

                                                                          delay(100);
                                                                          }

                                                                          void generate3PhasePWM(float frequency) {
                                                                            if (frequency == 0) {
                                                                                // If frequency is zero, set PWM outputs to zero
                                                                                    analogWrite(pwmPinA, 0);
                                                                                        analogWrite(pwmPinB, 0);
                                                                                            analogWrite(pwmPinC, 0);
                                                                                              } else {
                                                                                                  // Calculate the time period of one cycle
                                                                                                      float period = 1000000.0 / frequency; // Period in microseconds

                                                                                                          // Generate 3-phase signals with 120-degree phase shift
                                                                                                              unsigned long time = micros() % (unsigned long)period;

                                                                                                                  int pwmA = 128 + 127 * sin(2 * PI * time / period);
                                                                                                                      int pwmB = 128 + 127 * sin(2 * PI * time / period + 2 * PI / 3);
                                                                                                                          int pwmC = 128 + 127 * sin(2 * PI * time / period - 2 * PI / 3);

                                                                                                                              analogWrite(pwmPinA, pwmA);
                                                                                                                                  analogWrite(pwmPinB, pwmB);
                                                                                                                                      analogWrite(pwmPinC, pwmC);
                                                                                                                                        }
                                                                                                                                        }