// Cereated by Razman Ayop on 24 August 2024 to 8 September 2024
// The objective is to help students under Academic Service Learning (ASL) to visualize how PWM & MPPT charge controller works
// The project also is made to test the complexity of the project to ensure it is acceptable for Final Year Project (FYP) or not.

include

include

// 0. Parameters
// 0.1. Battery
float SOC; // State of Charge (SOC)
float Vbat_nom=24; // Nominal Battery Voltage, V
float SOCnom=0.5; // Nominal SOC
float SOCini=0.5; // Initial SOC
float SOCmin=0.2; // Minimum SOC
float SOCmax=0.95; // Maximum SOC
float SOCrc=0.5; // Reconnect SOC
float m_Vbat=8; // Vbat Gradient, V/SOC
float Cbat=40000; // Battery Capacity, W/s
float Vbat; // Battery Voltage, V
float Ibat; // Battery Current. +Charge, -Discharge.
float Pbat; // Battery Power,W
float Ebat; // Battery Energy, Ws
float Ebat_sto0=SOCini*Cbat; // Previous Battery Energy Storage, Ws
float Ebat_sto; // Battery Energy Storage, Ws

// 0.2. PV Model
float Voc_stc=50; // STC Open Circuit Voltage, V
float Vmp_stc=40; // STC Maximum Power Voltage, V
float Isc_stc=11; // STC Short Circuit Current, A
float Imp_stc=10; // STC Maximum Power Current, A
float Ns=1; // Number of Series PV Module
float Np=1; // Number of Parallel PV Module
float Voc; // Open Circuit Voltage, V
float Vmp; // Maximum Power Voltage, V
float Isc; // Short Circuit Current, A
float Imp; // Maximum Power Current, A
float G=1000; // Irradiance, W/m^2
float Gmax=1000; // Maximum Irradiance, W/m^2
float Vpv; // PV Voltage, V
float Ipv; // PV Current, A
float Ppv; // PV Power, W
float Epv; // PV Energy, Ws
float Vpv0=Vbat_nom; // Set PV voltage same as battery voltage
float Ipv0=1; // PV Current

// 0.3. Load Parameters
float Vload=0; // Load Voltage, V
float Iload=0; // Load Current, A
float Ploadmax=700; // Ploadmax, W
float Pload; // Load Power, W
float Eload; // Load Energy, Ws

// 0.4. Other Parameter
float Vstep=0.5; // P&O MPPT Voltage Step, V
float tsam=1; // Sample Time, s
float Sload=0; // Load Switch, 0=On, 1=Off
float Spv=0; // PV Switch, 0=On, 1=Off
int MODE=1; // Operating Mode. 0=PWM, 1=MPPT
float dPV; // Change of Power-Voltage
float Vref=Vbat_nom; // Reference Voltage
float T=12345; // Test Parameter

// 0.5. Input
int pinG=A0; // G ADC Pin
float valG=1000; // G Value
int pinLoad=A1; // Load ADC Pin
float valLoad; // Load Value
int pinMod=2; // Mode Digital In Pin

// 0.6. Output
LiquidCrystal_I2C lcd(0x27, 20, 4); // set the LCD address to 0x27 (SDA A4, SCL A5) for a 20 chars and 4 line display

void setup() {
// Initiate Serial Monitor
Serial.begin(9600);
Serial.print(“\n\nInitiate Charge Controller\n”);

// Set Digital Input
pinMode(pinMod,INPUT);

// Set LCD
lcd.init(); // initialize the lcd
lcd.backlight(); // Turn on the LCD screen backlight
}

void loop() {
// 1. Component Models
// 1.1. PV Array Model
delay(500);
valG=analogRead(pinG);
G=valG/1023Gmax; Voc=NsVoc_stc;
Vmp=NsVmp_stc; Isc=G/1000NpIsc_stc; Imp=G/1000Np*Imp_stc;

// 1.2. Battery Model
SOC=Ebat_sto0/Cbat;
Vbat=m_VbatSOC+(Vbat_nom-m_VbatSOCnom);

// 1.3. Load
valLoad=analogRead(pinLoad);
Pload=valLoad/1023*Ploadmax;
if (Sload==1 && SOC<SOCrc){
Vload=0;
Iload=0;
Pload=0;
}
else {
Vload=Vbat;
Iload=Pload/Vload;
Sload=0;
}

// 2.0. PWM vs MPPT
MODE=digitalRead(pinMod);
if (MODE==LOW){
// 2.1. PWM Mode
Vpv=Vbat;
if (Vpv<=Vmp){
Ipv=(Imp-Isc)/VmpVpv+Isc; } else { Ipv=Imp/(Vmp-Voc)Vpv+(Imp-ImpVmp/(Vmp-Voc)); } Ppv=VpvIpv;
Vpv0=Vpv;
Ipv0=Ipv;
Vref=Vpv;
}

else {
// 2.2. MPPT Mode
Vpv=Vref;
if (Vpv<=Vmp){ Ipv=(Imp-Isc)/VmpVpv+Isc; } else { Ipv=Imp/(Vmp-Voc)Vpv+(Imp-ImpVmp/(Vmp-Voc)); } Ppv=VpvIpv; dPV=(Ppv-Vpv0Ipv0)(Vpv-Vpv0); if (dPV>=0) {
Vref=Vpv+Vstep;
}
else {
Vref=Vpv-Vstep;
}
Vpv0=Vpv;
Ipv0=Ipv;
}

// 3.0. Energy Management System (EMS)
Epv=Ppvtsam; Eload=Ploadtsam;
Spv=0;
Ebat=Epv-Eload; // +Charge, -Discharge
Ebat_sto=Ebat_sto0+Ebat;
SOC=Ebat_sto/Cbat;
if (Ebat>0){
// 3.1. Excess Energy
if (SOC>=SOCmax){
// 3.1.1. Battery Full
SOC=SOCmax;
Ebat=-Eload;
Ebat_sto=Ebat_sto0+Ebat;
Vpv=Voc;
Ipv=0;
Ppv=0;
Spv=1;
}
}
else {
// 3.2. Less Energy
if (SOC<=SOCmin){
// 3.2.1. Battery Depleted
SOC=SOCmin;
Ebat=Epv;
Ebat_sto=Ebat_sto0+Ebat;
Vload=0;
Iload=0;
Pload=0;
Sload=1;
}
}
Ebat_sto0=Ebat_sto;
Pbat=Ebat/tsam;
Ibat=Pbat/Vbat;

// 4.0. Serial Print
Serial.print(“Vpv = “);
Serial.print(Vpv);
Serial.print(“, Ipv = “);
Serial.print(Ipv);
Serial.print(“, Ppv = “);
Serial.print(Ppv);
Serial.print(“… Vbat = “);
Serial.print(Vbat);
Serial.print(“, Ibat = “);
Serial.print(Ibat);
Serial.print(“, Pbat = “);
Serial.print(Pbat);
Serial.print(“, SOC = “);
Serial.print(SOC);
Serial.print(“… Vload = “);
Serial.print(Vload);
Serial.print(“, Iload = “);
Serial.print(Iload);
Serial.print(“, Pload = “);
Serial.print(Pload);
Serial.print(“. TEST = “);
Serial.print(valLoad);
Serial.print(“. \n”);

// 5.0. LCD Display
lcd.clear();
//PV
lcd.setCursor(0, 0);
lcd.print(“PV: “);
lcd.setCursor(4, 0);
lcd.print(Vpv);
lcd.setCursor(8, 0);
lcd.print(“V “);
lcd.setCursor(10, 0);
lcd.print(Ipv);
lcd.setCursor(14, 0);
lcd.print(“A “);
lcd.setCursor(16, 0);
lcd.print(Ppv);
lcd.setCursor(19, 0);
lcd.print(“W “);

//Load
lcd.setCursor(0, 1);
lcd.print(“LD:”);
lcd.setCursor(4, 1);
lcd.print(Vload);
lcd.setCursor(8, 1);
lcd.print(“V “);
lcd.setCursor(10, 1);
lcd.print(Iload);
lcd.setCursor(14, 1);
lcd.print(“A “);
lcd.setCursor(16, 1);
lcd.print(Pload);
lcd.setCursor(19, 1);
lcd.print(“W “);

//BAT
lcd.setCursor(0, 2);
lcd.print(“BA:”);
lcd.setCursor(4, 2);
lcd.print(Vbat);
lcd.setCursor(8, 2);
lcd.print(“V “);
lcd.setCursor(10, 2);
lcd.print(Ibat);
lcd.setCursor(16, 2);
lcd.print(“A “);
lcd.setCursor(4, 3);
lcd.print(SOC*100);
lcd.setCursor(8, 3);
lcd.print(“% “);
lcd.setCursor(10, 3);
lcd.print(Pbat);
lcd.setCursor(16, 3);
lcd.print(“W “);
}