Rushi DalalRoman FragasseMilind Furia
Published © GPL3+

MPPT Vehicle

A vehicle that uses maximum power point tracking to harvest solar energy so that maximum power output can be achieved.

IntermediateFull instructions provided1,496
MPPT Vehicle

Things used in this project

Hardware components

MSP-EXP432P401R SimpleLink MSP432 LaunchPad
Texas Instruments MSP-EXP432P401R SimpleLink MSP432 LaunchPad
×1
Fuel Tank BoosterPack
To provide battery power to TI LaunchPads and enables their portability
×1
BOOST-DRV8848
To drive a brushed DC motor
×1
HS-311 Standard Servo
×1
3-Speed Crank Axle Gearbox
×1
LM339 Quad Comparator
×1

Hand tools and fabrication machines

Soldering iron (generic)
Soldering iron (generic)
Super Glue
Bandsaw

Story

Read more

Schematics

Analog Front End

Comparator circuit that is essentially a light detection circuit. Functions as an analog interrupt block for the MPPT vehicle. Based on whether the vehicle detects light or not, it will move accordingly. Then we utilize the Perturb and Observe algorithm to optimize power output.
(Designed in TINA-TI, a SPICE-based analog simulation program)
The issue we ran into here was that the circuit ceased to function properly when we transferred it to a perforated prototyping board.

Code

Panel_MPPT_ALG_FP_submit.ino

C/C++
MPPT used to control a servo attached to a mast with a solar panel glued to the end of it. Duty cycles much quicker than its drive shaft counterpart.
// Servo library used to make panel tilt algorithm
//this code wil track the maximum input power of the sun for a given angle
//by way of Perturb and Observe (loosely based on the popular P&O algorithm)



#include <Servo.h> 
 
Servo myservo;                                //create servo object to control a servo 
                                              // a maximum of eight servo objects can be created 
 
int pos = 0;                                  // variable to store the servo position 
float Pdiff = 0;
double R = 2000000;                               //resistance in ohms of the current sampling resistor (2Mohm)
int pos_start = 45;                           //dynamic value for the starting position of the servo controlling the panel angle

void setup() 
{ 
  Serial.begin(115200);                        //intiialize serial communication for printing values//debug basically
  myservo.attach(9);                         // attaches the servo on pin 9 to the servo object 
  
} 

 
void loop() 
{ 
  //Initalize measurements
  float Vmeas = analogRead(2);                  //positive side panel voltage on pin2
  float Vmeas_I = analogRead(5);                //negative side panel voltage reading (across 2.2 ohm resistor) on pin 5
  
  float V_1 = 0;                             //might convert to int in the interest of saving memory
  float I_1 = 0;
  float P_1 = 0;
  float V_2 = 0;
  float I_2 = 0;
  float P_2 = 0;
  float Vc = (3.3/1023);                     //voltage correction factor for the ADC (note: may be more than 10 bit ADC on 432)
  //=========================================================================================================================
  //Track in the positive direction....
  //=========================================================================================================================
  for(pos = pos_start; pos < 135; pos += 1)  // goes from  a min of 45 degrees to  max of 180 degrees //in steps of one degree
  {  
    
    Vmeas = analogRead(2);                  //positive side panel voltage on pin2
    Vmeas_I = analogRead(5);                //negative side panel voltage reading (across 2.2 ohm resistor) on pin 5
    
    V_1 = 2*Vmeas*Vc;                          //measure voltage at past time stamp
    I_1 = ((Vmeas-Vmeas_I)*Vc)/R;            //measure current at past time stamp
    P_1 = V_1*I_1;                           //calculate power 
    myservo.write(pos);                      // tell servo to go to position in variable 'pos'// Perterb!!
    Serial.print("\n\nP_1\n");
    Serial.println(P_1);                     //optional, only to view the voltages we are getting
    delay(1000);                              // waits 50ms for the servo to reach the position 
    
    Vmeas = analogRead(2);                  //positive side panel voltage on pin2
    Vmeas_I = analogRead(5);                //negative side panel voltage reading (across 2.2 ohm resistor) on pin 5
    
    V_2 = 2*Vc*Vmeas;                             //Repeat all measurements again (Observe!!)
    I_2 = ((Vmeas-Vmeas_I)*Vc)/R;
    P_2 = V_2*I_2;
    Serial.print("\n\nP_2\n");
 
    Pdiff = P_2 - P_1;
    if (Pdiff < 0)                             //if the power is dropping, go the other direction, if it is not dropping keep climbing the hill!
      {
        //Serial.println(Pdiff);            //debug line
        pos_start = pos;                     //update the start position so that the controller does not move when entering the next loop
        break;                               //break into the next for loop
      }
    
  } 
  pos_start = pos;
  
  //=============================================================================================================================
  //Track in the negative direction.... Constantly Updatting and tracking the maximum powerpoint
  //=============================================================================================================================
  for(pos = pos_start; pos >= 45; pos -= 1)  // goes from  a max of 180 degrees to  min of 45 degrees //in steps of one degree
  {  
    
    Vmeas = analogRead(2);                  //positive side panel voltage on pin2
    Vmeas_I = analogRead(5);                //negative side panel voltage reading (across 2.2 ohm resistor) on pin 5
    
    V_1 = 2*Vc*Vmeas;                             //measure voltage at past time stamp
    I_1 = (Vmeas-Vmeas_I)/R;                 //measure current at past time stamp
    P_1 = V_1*I_1;                           //calculate power 
    myservo.write(pos);                      // tell servo to go to position in variable 'pos'// (Perterb!!)
    
    //Serial.println(-(V_1));                  //debug line
    
    delay(1000);                              // waits 50ms for the servo to reach the position 
    Vmeas = analogRead(2);                  //positive side panel voltage on pin2
    Vmeas_I = analogRead(5);                //negative side panel voltage reading (across 2 Mohm resistor) on pin 5
    
    
    V_2 = 2*Vc*Vmeas;                             //Repeat all measurements again (Observe!!)
    I_2 = (Vmeas-Vmeas_I)/R;
    P_2 = V_2*I_2;
    Pdiff = P_2 - P_1;
    //Serial.println(-(V_2));                  //debug line
    if (Pdiff< 0)                             //if the power is dropping, go the other direction, if it is not dropping keep climbing the hill!
      {
        pos_start = pos;                     //update the start position so that the controller does not move when entering the next loop
        break;                               //break into the next for loop
      }
  
  } 
  //=============================================================================================================================
  //Enter the postive direction loop again....
  //==============================================================================================================================
pos_start = pos;
//Serial.print("Loop Switch"); //debug line
} 

Drive Shaft Code

C/C++
MPPT driving the entire vehicle forwards and backwards to steer it away from obstacles that could inhibit sunlight.
// PWM control of the Brushed DC motor shaft
//No libraries needed :)
//note: code can probably be broken down into a couple of if statements in the void loop
//we will perterb the motor very slowly (at least a hell of a lot slower than the angle of the panel)
 
float Pdiffs = 0;
double Rs = 2000000;                               //resistance in ohms of the current sampling resistor (2Mohm)
float V_1s = 0;                             //might convert to int in the interest of saving memory
float I_1s = 0;
float P_1s = 0;
float V_2s = 0;
float I_2s = 0;
float P_2s = 0;
float Vcs = (3.3/1023);                    //voltage correction factor for the ADC (note: may be more than 10 bit ADC on 432)

void setup() 
{ 
  Serial.begin(115200);                        //intiialize serial communication for printing values   
} 

 
void loop() 
{ 
  //the same measurements will need to be taken in parallel, think of the drive shaft as its own seperate subsytem running regardless of what the panel is doing
  //the shaft will have no memory of what the panel did in the preceding steps, rather, it will run on its own memory schema
  
  
  //Initalize measurements

  float Vmeass = analogRead(2);                  //positive side panel voltage on pin2
  float Vmeas_Is = analogRead(5);                //negative side panel voltage reading (across 2.2 ohm resistor) on pin 5
  
  //perform calculations
  V_2s = 2*Vmeass*Vcs;                          //measure voltage at past time stamp
  I_2s = ((Vmeass-Vmeas_Is)*Vcs)/Rs;            //measure current at past time stamp
  P_2s = V_2s*I_2s;                           //calculate power 
  
  //Serial.print("\n\nP_2s\n");  //debug lines
  //Serial.println(P_2s);                     //optional, only to view the voltages we are getting
                     
  
  //=========================================================================================================================
  //Enter if statement to move the car appreciably in one direction or the other...
  //=========================================================================================================================
  
  //PWM section of code
  //==========================================================================================================================
  //note, cannot use the analogWrite function, have to resort to -bit banging-
  if(Pdiffs<0)  // goes from  a min of 45 degrees to  max of 180 degrees //in steps of one degree
      { 
        for (int i = 0 ; i == 10; i += 1)
        {
        Serial.write("flag");  
        digitalWrite(13, LOW); //H-Bridge commands for the DC motor (see truth table at bottom of code)// AIN1
        digitalWrite(12, HIGH);
        delay(25);
        digitalWrite(13, LOW);                                                                          //AIN2
        digitalWrite(12, LOW);
        delay(75);
        //currently a 25% duty cycle with T = 100ms for a total PWM on-time of 1 second
        }
      }
  else
      {
       for(int j = 0; j ==10; j +=1)
       { 
       digitalWrite(13, HIGH);
       digitalWrite(12, LOW);
       delay(25);
       digitalWrite(13, LOW);
       digitalWrite(12, LOW);
       delay(75);
       }
      }
    
    digitalWrite(13, LOW);//stop the motor at next perturbation point
    digitalWrite(12, LOW);
    //========================================================================================================================================
    
    
    //take a new measurement at the next place
    Vmeass = analogRead(2);                          //positive side panel voltage on pin2
    Vmeas_Is = analogRead(5);                        //negative side panel voltage reading (across 2.2 ohm resistor) on pin 5
    
    V_1s = 2*Vcs*Vmeass;                               //Repeat all measurements again (Observe!!)//note a voltage divider has been used to attenuate the voltage to a manageable level on pin 5
    I_1s = ((Vmeass-Vmeas_Is)*Vcs)/Rs;              
    P_1s = V_1s*I_1s;
    //Serial.print("\n\nP_1s\n");         //debug lines
    //Serial.print(P_1s);
    Pdiffs = P_2s - P_1s;                              //this is the Vdiff calculation that will determine the direction that the car moves
    delay(100000);                                  //extremely long delay added to ensure slow perturbation
    
} 

Credits

Rushi Dalal

Rushi Dalal

1 project • 4 followers
DIY with TI 2015
Roman Fragasse

Roman Fragasse

1 project • 2 followers
In my spare time I enjoy hacking the kernel.
Milind Furia

Milind Furia

1 project • 2 followers
Tech wizard, blah blah blah

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