Created October 24, 2018

On-line Industrial Battery Bank Monitor

On-line battery monitoring

Things used in this project

Hardware components

Infineon CoolMOS C7 Gold SJ MOSFET

STMicroelectronics STM32 Nucleo-64 Board

tlp3547 OptiRelay

Software apps and online services

mbed IDE

Story

Content guidelines

1、Problem to solve

Industrial battery banks with large scale., with voltage of 220V DC and stacked batteries.

On-Line Battery bank monitor with reasonable cost would be the most importance part. With Infineon CoolMOS C7 shall solve the problem with voltage, current, temperature with elastic control, fast response, compact in size and flexible in design.

With CoolMOS G7 MOSFET, the measuring circuit can be wired parallel, using CoolMOS G7 MOSFET as contactless switch to toggle measuring mode.

And the CoolMOS G7 MOSFET can replace mechanic relay and mechanical Protection Circuit Breaker to trip off the circuit when there is short-circuit or abnormal temperature rise on Fault Battery.

There are two CoolMOS G7 MOSFET shall be used for one-battery-pack, one for measuring circuit and one for Outgoing wire protection.

2. Hardware and software to build

2.1 There are many choice. The Nucleo-stm32F410RB is used in this design, the MCU balance the cost and performance in good condition.

Shun resistor for voltage and coulomp counting resistor for current sensing. The temperature sensor for is TI-tempsensor.

Other auxiliary parts, like LCD1602 and wirings etc.

2.2 The mbed.org can be good in design.

2.3 New hardware is included, THE MKR1000 arduino board WIFI.

2.4 The thingspeak API

3. Here is the program

3.1 Here is the program loop. Interrupt and Ticker are used.

3.2 Codes

The main part

InterruptIn control(USER_BUTTON);
InterruptIn protection(D0);
DigitalOut trip_protection(D0);
DigitalOut trip_control(D1);
Ticker mticker;
Ticker pticker;
int main(){
   lcd.cls();
   textLCD("Battery Monitor.", 1);
   wait(2);
   // Assign functions to button
   protection.fall(&protection_on);
   control.fall(&control_ON_OFF);    
   trip_protection=0;
   trip_control= 0;   // Start Close then trip on.
   control_ON_OFF();
   while(1){
          //closeLCD();
   } // end of while
}    // end of main

The manually controlled On_Off status for the control, via One of the MOSFET，

void control_ON_OFF() {
   trip_control = !trip_control;
   if (trip_control == 1) {
       led1= 1 ;
       trip_protection=1;
           textLCD("BMS is On.      ", 0);
           textLCD("Ready to go.    ", 1);
           wait(2);
       //trip_control= 1;  
          textLCD("VOL=           V", 0);
          textLCD("CUR=          mA", 1);
          mticker.attach(&measuretick, MEASURESPAN);  
          pticker.attach(&protectick, 0.1);  
       }
   else if (trip_control != 1) {
       //trip_control= 0;  
       led1 = 0;           
          textLCD("BMS is Off.     ", 0);
          textLCD("Trip Off.       ", 1);
          mticker.detach(); 
          wait(1);
          //trip_protection=0; 
          //pticker.detach(); 
       }
}

Another Protection pin vs another MOSFET.

void protection_on() {
...
}

Analogue to digital for A0, A1, A2 pins, trigger Protection if there is boolean FAULT.

void protectick() {
    //char* meas_v,meas_i,meas_t;
   float ana_read_a1,ana_read_a2,ana_read_a0;
   bool fault;
   ana_read_a1 = VOL_REF* (voltage_value.read()); // Read the analog input value (value from 0.0 to 1.0 = full ADC conversion range) and Converts value in the 0V-3.3V range
   ana_read_a2 = CUR_REF* (current_value.read()); 
   ana_read_a0 = TEM_REF* (temperature_value.read()); 
   fault = (ana_read_a1 > VOLMAX) or (ana_read_a2 > CURMAX ) or (ana_read_a0 > TEMMAX);
       printf("measure = %f:%f:%f.\n",  ana_read_a1,ana_read_a2,ana_read_a0);
       if (fault) {
           trip_protection=0;        
       }
}

4. Wiring

4.1 Here is the wiring diagram

4.2 The conversion ratio for voltage in shun resistor and serial current resistor shall be fix according to calculation.

For conversion ratio of voltage = 1M /100k =10 times

For serial current sensing resistor of 10 ohms, divided by 10 in the code, as of

#define VOL_REF 3300 * 10  //With convert RATIO in shun resistors
#define CUR_REF 1000 / 10     //With 10ohm Resistor

4.3 Use of CoolMOS™ C7

As per the datasheet, the 5V is enough for CoolMOS™ C7 Drain-Gate drive voltage, that is shown in this diagram.

But for safety reason and fast response, one opti-MOSFET drive of 12V is necessary. I have FAIRCHILD FOD 8314 ready for better performance.

1 / 2

5. Demo RUNNING

5.1 Wiring according to the sketch

5.2 Plug and running

Code

// onLineBatteryMonitor
# include <stdio.h>
# include <stdlib.h>
#include "mbed.h"
#include "TextLCD.h"    // LCD1602


/*********************
#define VOL_REF 3300
#define CUR_REF 1000
#define TEM_REF 100
**********************/
#define VOL_REF 3300 * 10  //With convert RATIO in shun resistors
#define CUR_REF 1000 / 10     //With 10ohm Resistor
#define TEM_REF 100
#define VOLMAX 12       // In 12V
#define CURMAX 500      // In 500mA
#define TEMMAX 100      // In 100C degree
#define MEASURESPAN  5          // in 20s


DigitalOut led1(LED1);

AnalogIn voltage_value(A1);
AnalogIn current_value(A2);
AnalogIn temperature_value(A0);


InterruptIn control(USER_BUTTON);
InterruptIn protection(D0);
DigitalOut trip_protection(D0);
DigitalOut trip_control(D1);

Ticker mticker;
Ticker pticker;

TextLCD lcd(D8, D9, D4, D5, D6, D7);



// Functions

// display text on LCD
void textLCD(char *text, int line) {
    char tmpBuf[16];
    for (int i = 0; i < 16; i++) tmpBuf[i] = 0x20;
    for (int i = 0; i < strlen(text); i++) {
        if (i < 16) tmpBuf[i] = text[i];
        lcd.locate(i, line);
        lcd.putc(tmpBuf[i]);
    }
}

void digitLCD(int val, int line) {
    char tmpBuf[8];
    //printf("bms = %d\n",  val);
    for (int i = 4; i < 12; i++) tmpBuf[i] = 0x20;
    int i=12;
    while (val){
        tmpBuf[i] = (val % 10) + '0';  
        val =val /10;
        lcd.locate(i, line);
        lcd.putc(tmpBuf[i]);
        i--;
        }           
} // end  of digitLCD
          



void measuretick() {

    float ana_read_a1,ana_read_a2,ana_read_a0;
    
    
    ana_read_a1 = VOL_REF* (voltage_value.read()); // Read the analog input value (value from 0.0 to 1.0 = full ADC conversion range) and Converts value in the 0V-3.3V range
    ana_read_a2 = CUR_REF* (current_value.read()); 
    ana_read_a0 = TEM_REF* (temperature_value.read()); 
        //printf("Voltage = %f: Current = %f: Temperature = %f.\n",  ana_read_a1,ana_read_a2,ana_read_a0);
       digitLCD( floor(ana_read_a1+0.5), 0 );
       digitLCD( floor(ana_read_a2+0.5), 1 );
       

}

void protectick() {
    float ana_read_a1,ana_read_a2,ana_read_a0;
    bool fault;
    
    ana_read_a1 = VOL_REF* (voltage_value.read()); // Read the analog input value (value from 0.0 to 1.0 = full ADC conversion range) and Converts value in the 0V-3.3V range
    ana_read_a2 = CUR_REF* (current_value.read()); 
    ana_read_a0 = TEM_REF* (temperature_value.read()); 
    fault = (ana_read_a1 > VOLMAX) or (ana_read_a2 > CURMAX ) or (ana_read_a0 > TEMMAX);
        if (fault) {
            trip_protection=0;        
        }
}



void control_ON_OFF() {
    trip_control = !trip_control;

    if (trip_control == 1) {
        led1= 1 ;
        trip_protection=1;
            textLCD("BMS is On.      ", 0);
            textLCD("Ready to go.    ", 1);
            wait(2);
        //trip_control= 1;  
           textLCD("VOL=          mV", 0);
           textLCD("CUR=          mA", 1);
           mticker.attach(&measuretick, MEASURESPAN);  
           pticker.attach(&protectick, 0.1);  
        }
    else if (trip_control != 1) {
        //trip_control= 0;  
        led1 = 0;           
           textLCD("BMS is Off.     ", 0);
           textLCD("Trip Off.       ", 1);
           mticker.detach(); 
           wait(1);
           //trip_protection=0; 
           //pticker.detach(); 
        }
}
void protection_on() {
           //trip_protection=0;
           if (trip_control==1){
               textLCD("BMS Fault.      ", 0);
               textLCD("Trip Off.       ", 1);
               pticker.detach(); 
               } 
}

int main(){
        lcd.cls();
    textLCD("Battery Monitor.", 1);
    wait(2);
    
    // Assign functions to button
    protection.fall(&protection_on);
    control.fall(&control_ON_OFF);    
    
    trip_protection=0;
    trip_control= 0;   // Start Close then trip on.
    control_ON_OFF();


        
    while(1){
           //closeLCD();
             
    } // end of while
}    // end of main

/* BMS on MKR1000 for thingspeak */

#include <SPI.h>
#include <WiFi101.h>
#include <Wire.h>
#include "ThingSpeak.h"
#include "arduino_secrets.h" 

#define MKR_ADDR  0x60
#define I2CCLOCK  100000

///////please enter your sensitive data in the Secret tab/arduino_secrets.h
char ssid[] = SECRET_SSID;        // your network SSID (name)
char pass[] = SECRET_PASS;    // your network password (use for WPA, or use as key for WEP)
int status = WL_IDLE_STATUS;     // the Wifi radio's status
WiFiClient  client;

unsigned long myChannelNumber = SECRET_BMS_CH_ID;
const char * myWriteAPIKey = SECRET_BMS_WRITE_APIKEY;
const char * myReadAPIKey = SECRET_BMS_READ_APIKEY;
unsigned int bmsFieldNumber = 3;
int ts_number = random(0,100);
int bms_voltage,  bms_current,  bms_temperature=0;
bool Fault=false;


void thingspeak_on(){  
  // check for the WiFi module:
  if (WiFi.status() == WL_NO_SHIELD) {
    Serial.println("WiFi shield not present.\n");
    while (true);
  }

  while (status != WL_CONNECTED) {
    Serial.print("Attempting to connect to WPA SSID: ");
    Serial.println(ssid);
    status = WiFi.begin(ssid, pass);
    delay(10000); 
  }
  
  Serial.print("You're connected to the network for ThingSpeak Update.");
   ThingSpeak.begin(client);  // Initialize ThingSpeak
   return;
}

void receiveEvent(int howMany){   
      String statusStr = "";     
      String comdata = "";
      int i=0;
      int index;
      //int index = comdata.indexOf(','); int x = str.substring(0, index).toInt(); int y = str.substring(index + 1, str.length()).toInt();

  while(0 < Wire.available()) // loop through the last
  {
    char c = Wire.read(); // receive byte as a character
    comdata += c;
    i++;
    if (i>24) { break; }
    Serial.print(c);         // print the character
  }
  // First data,
  index = comdata.indexOf(',');
  bms_voltage=comdata.substring(0,index).toInt();
  comdata=comdata.substring(index+1,comdata.length()); 
  // 2nd and 3rd data,
  index = comdata.indexOf(',');
  bms_current=comdata.substring(0,index).toInt();
  bms_temperature=comdata.substring(index+1,comdata.length()).toInt(); 

      // set the fields with the values
      ThingSpeak.setField(1, bms_voltage); 
      ThingSpeak.setField(2, bms_current);
      ThingSpeak.setField(3, bms_temperature);
      statusStr = String("Three fields set.");
      
      int x = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);
      if(x == 200){
        Serial.println("Channel update successful. With number of "+String(ts_number) );
        }
        else{
          Serial.println("Problem updating channel. HTTP error code " + String(x));
          }
}  


void setup() {
  //Initialize serial and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {; }
  Wire.begin(MKR_ADDR);    // join i2c bus (address optional for master)
  Wire.setClock(I2CCLOCK); 
  Wire.onReceive(receiveEvent); // register event
  thingspeak_on();
  
}

void loop() {    
  //Serial.println("\nLoop On.");
  //delay(100);   
  // Network connection once every 20 seconds:
}

Credits

F. Yao

18 projects • 13 followers

On-line Industrial Battery Bank Monitor

Things used in this project

Hardware components

Software apps and online services

Story

Schematics

Circuit Diagram Simple Offline Solution

Showcase of Circuit Diagram for BMS with more batteries

Circuit Diagram for BMS with backend connection

Code

onLineBatteryMonitor Simple solution offline

onLineBatteryMonitor.NUCLEO_F410RB.bin offline solution

I2C_bms_thingspeak.ino Cloud Supported Part

Credits

F. Yao

Comments

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On-line Industrial Battery Bank Monitor

On-line Industrial Battery Bank Monitor

Things used in this project

Hardware components

Software apps and online services

Story

Schematics

Circuit Diagram Simple Offline Solution

Showcase of Circuit Diagram for BMS with more batteries

Circuit Diagram for BMS with backend connection

Code

onLineBatteryMonitor Simple solution offline

onLineBatteryMonitor.NUCLEO_F410RB.bin offline solution

I2C_bms_thingspeak.ino Cloud Supported Part

Credits

F. Yao

Comments