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Project Design Document (PDD)

Three-phase Microprocessor Relay (THMPR)

Author: Wade Archer Date:12-8-18

Revision 1 Date:12-8-18




1.0 Architectural Design (Refer to PA4)

• Delivers warning and current status information via Wi-Fi communication

• Disconnects system from power supply

• Collects sensor readings from supply line

• Uses collected data to make system level decisions

2. Graphically relate the functional elements to the physical elements of the

design:

Functional Elements:

Customer Need Functional Element Physical Element 1. Quick decisions “ uses collected data…” Micro controller

2. Smart “ delivers warning…” RF transceiver 3. safe “ disconnects…” disconnect relay

4. “ collects sensor…” voltage/ current sensor

Architectural Graphic:

2.0 Hardware Design

Current sensors/Hall sensors

− input to the current sensors will be a single-phase AC signal

− the purpose of the sensor is to take measurement of the current present in the

wire of interest

− the output of the current sensor will be an analog voltage signal that correlates to

the what current is there

Current transformers

− the input of the current transformers (CT) will be one of the phases from main

supply

− the purpose of the CT measures the current in the phase while isolating the

THMPR from main power, this will be beneficial in large systems

− the output of the transformer will be fed into one of the inputs of the LM324

operational amplifier (op-amp)

LM324 operational amplifiers

− the input of the op-amp will be a single-phase voltage or current reading of the

three-phase voltage supply

− the purpose of the op-amps will be to create square wave signals for their use in

zero-crossing detection and for frequency measurement of each phase

− the output of the op-amps will be square wave signals that represents either the

present voltage or current in that single phase

XOR gate

− the input of the two input XOR gate will be two square wave signals from two of

the op-amps

− the purpose of the XOR gate is to detect the time difference between the two

signals coming from the op-amps. Essentially it will be detecting the phase

difference between the current and voltage signal

− the output of the XOR gate will be a square wave that will represent the time

delay between the two signals and be fed into the microcontroller

STM32f103c8t6 “blue pill” microcontroller

− the input of the microcontroller will multiple signals -both digital and analog-

that correlate to the collected data of the sensor devices

− the purpose of the microcontroller will be to use the collected data in calculations

that will dictate the functions of the system as whole

− the output of the microcontroller will be multiple digital signals that connect to

different hardware components that will carry out their functions as dictated by

the micro controller

the Disconnect relay

− the inputs of this relay will be an AC signal from the micro controller that will

activate the disconnect relay, and the three single phase supply lines that are

being monitored

− the purpose of the disconnect relay will be to break the circuit connecting the

power supply from the system

− the output of the disconnect is meant to be another three single-phase lines that

would act as supply lines

ESP8266-01 Wi-Fi module

− the input of this system would be a digital signal that it would send to the user’s

PC

− the purpose of this device is to allow the user to be kept updated on the condition

of their power supply if something where to go wrong, or if there is something to

be concerned over

− the output of this system is a signal that can be picked up by the user’s PC

2.1 Theory of operation (required)

the purpose of this product is to act as a safety measure for power supply

systems. Essentially if the product detects an irregularity in the supplies’ current that could cause damage to those systems or bodily harm and will

disconnect the system from its malfunctioning power supply.

it can be described in three steps:

2.2 Schematics (required)

2.3 State Flow Diagrams (as required)

None so far

2.4 Timing Diagrams (as required)

None so far

3.0 Software Design

( blocks described are from the main loop of the program)

Frequency measurement

− input of this will be pulse length measurements from hardware relating to the

signal generated by the op-amp from the phase voltage

− the purpose of this is calculate the frequency of the input phase to ensure a

consistent frequency between all phases

− the output of this block will be frequency measurements of each phase

Overcurrent calc.

− the input of this section will be the output of the sampling section

− the purpose of this section is to make comparison calculations with input data

and the set values. This is done by taking in input data and running it through

calculations focusing on area of interest in power systems, such as power

factor, and comparing that calculated value with normal and acceptable values

− the output of this block will be digital signals that will either activate the

disconnect relay, or be transmitted through the Wi-Fi module

Tell user/Communicate with Wi-Fi Module

− the input of this block will be the fault check flag used elsewhere in the program

− this block will be used to “write” to the user interface, updating information that

would be relevant to the user about the state of the relay using the fault flag to

decide what is sent to user interface

− the output is data describing the current state of the THMPR to the user interface

Power Factor Reading

− the input for this block is the DC signal timing signal output from the zero-

crossing detection circuit

− this function is meant to measure the phase difference between the voltage and

current of that phase and calculate the power factor from it.

− The output of this block will be the calculated power factor measurement of each

phase

3.1 Software Inter-Relationships Block Diagram

(main)

3.2 code of critical software elements //three phase relay test code for Senior project

//Wade Archer

// created: 4-13-19

// last updated: 5-8-19

//Interfacing ESP8266 Wi-Fi with STM32F103C8

//---------------------------------------------------------------

//NOTE: Serial is serial monitor with baud rate(9600)

//NOTE: Serial1 (TX2, RX2)is connected with ESP8266(RX,TX)respectively with baud rate (115200)

String webpage = ""; //String variable to store characters

int i = 0, k = 0, x = 0; //integer variables

//float pf_data; // data to be sent from pf calculation

String readString; //using readString feature to read characters

boolean No_IP = false; //boolean variables

String IP = ""; //String variable to store data

char temp1 = '0'; //character variable

String names = "Wade ArcherChico State Senior Design Project"; //String with html

notations

String data = "Data Received Successfully....."; //String with html

String danger = " Power Source is in the DANGER ZONE."; // string with html notation

String prblm = " a phase is faultly, tripped relay, reset the THMPR"; // string with html

notation

String safe = " this phase is operating normally";

String space = " ";

int THMPR_flag[] = {0, 0, 0}; // used to tell Send() whats going on with the rest of the relay, one for

each phase

//---------------------------------------------------------------

//Measuring AC Current Using ACS712 hall sensor

//---------------------------------------------------------------

//setting up arrays for all hall sensors

const int sensorIn[3] = {PA4, PB1 , PA0}; // setting input pins

int mVperAmp = 185; // use 185 for 5A, 100 for 20A Module, and 66 for 30A Module

// define variables for calculations

//float Voltage[3];

float VRMS[3];

float AmpsRMS[3];

//---------------------------------------------------------------

// power factor calculation, three phase

//---------------------------------------------------------------

const int pf_in[3] = {PB4, PA12, PA15};// setting up array for input pins from all three phases

float rads = 57.29577951; // 1 radian = approx 57 deg.

float degree = 360; // degrees

float frequency = 60; // frequency of supply for North America

float nano = 1 * pow (10, -6); // Multiplication factor to convert micro seconds into seconds

// Define floats to contain calculations

float pf[3];

float angle[3];

float pf_max[3] = {0, 0, 0};

float angle_max[3] = {0, 0, 0};

int ctr;

//---------------------------------------------------------------

// Powerfeather Relay

//---------------------------------------------------------------

const int Signal[3] = {PB12, PB13, PB14};// signal output pins

//const int Reset[3] = {PA6, 0, 0};// reset pins

//---------------------------------------------------------------

// frequency measurement

//---------------------------------------------------------------

const int freqIn[3] = {PA11, PB8, PB15};

float Freqs[3];

//---------------------------------------------------------------

// fault, frequency, and powerfactor functions

//------------------------o---------------------------------------

void powerfactor() { // this function is used to measure and store the power factor of each phase

uint32_t start_time = millis();

Serial.print(" time since program started: "); Serial.println(start_time);

for (int b = 0; b <= 2; b++) { // Perform a measurement for each phase

for (ctr = 0; ctr <= 3; ctr++) // Perform 4 measurements then reset

{

// 1st line calculates the phase angle in degrees from differentiated time pulse

// Function COS uses radians not Degree's hence conversion made by dividing angle / 57.2958

uint32_t timing = pulseIn(pf_in[b], HIGH, 100000);

angle[b] = ((((pulseIn(pf_in[b], HIGH, 100000)) * nano) * degree) * frequency); // phase difference

(in degrees)= delta_t*360*f, pulseIn's timeout set to 10 sec

// pf[b] = cos(angle[b] / rads);

if (angle[b] > angle_max[b]) // Test if the angle is maximum angle

{

angle_max[b] = angle[b]; // If maximum record in variable "angle_max"

pf_max[b] = cos(angle_max[b] / rads); // Calc PF from "angle_max"

}

}

if (angle_max[b] > 360) // If the calculation is higher than 360

{

angle_max[b] = 0; // assign the 0 to "angle_max"

pf_max[b] = 1; // Assign the Unity PF to "pf_max"

}

else if (angle_max[b] == 0) // If the calculation is higher than 360

{

angle_max[b] = 0; // assign the 0 to "angle_max"

pf_max[b] = 1; // Assign the Unity PF to "pf_max"

}

Serial.print("phase"); Serial.println(b + 1);

Serial.print(" phase shift between I"); Serial.print(b + 1); Serial.print(" and V"); Serial.print(b + 1);

Serial.print(":");

Serial.print(angle_max[b], 2); // Print the result

Serial.print(", ");

Serial.print("power factor: ");

Serial.println(pf_max[b], 2);

angle[b] = 0; // Reset variables for next test

angle_max[b] = 0;

}

}

void getFrequency() {// this function takes in the pin that we would like to measure and returns the

frequency of that phase, it also checks if the phase has been disconnected

int Htime[3] = {0, 0, 0}; //integer for storing high time

int Ltime[3] = {0, 0, 0}; //integer for storing low time

float Ttime[3] = {0, 0, 0}; // integer for storing total time of a cycle


for (int b = 0; b <= 2; b++) {

Htime[b] = pulseIn(freqIn[b], HIGH); //read high time

Ltime[b] = pulseIn(freqIn[b], LOW); //read low time

Ttime[b] = Htime[b] + Ltime[b];

Freqs[b] = 1000000 / Ttime[b]; //getting frequency with Ttime is in Micro seconds

if (start_time > 1000) { // 1 seconds, setting a "timer" to wait for signals to settle

if ((pulseIn(freqIn[b], HIGH) == 0) || (pulseIn(freqIn[b], LOW) == 0)) { // looks to see if one phase

has been disconnected, if a pulse remains high longer than 1.5 second

// direct pin register manipulation

GPIOB->regs->ODR |= 0b0111000000000000;// setting B12,B13, B14 high, which are my relays

Serial.print(" time in milli seconds since program started, relay has disconnected: ");

Serial.println(start_time);

Serial.print(" lost phase"); Serial.println(b + 1);

THMPR_flag[0] = 1; THMPR_flag[1] = 1; THMPR_flag[2] = 1; // setting flags for webpage

break; // breaking from for loop

}

}

}

}

void flt_check(float Ampsrms[]) { // this function checks the current of the supply phases, deciding if a

fault has occured


double safei = 0.00; // the accepted current value reference point

double plus = safei + 0.010;

double neg = safei - 0.010; // can reset these variables as needed

double over = safei + 0.005;

double under = safei - 0.005;

for (int b = 0; b <= 2; b++) {

if (Ampsrms[b] >= (under) && Ampsrms[b] < (neg)) { // danger zone (-)

Serial.print("reached: danger zone (-) for phase "); Serial.println(b + 1);

THMPR_flag[b] = 2;

}

else if (Ampsrms[b] > (plus) && Ampsrms[b] <= (over) ) { // danger zone (+)

Serial.print(" reached: danger zone (+) for phase "); Serial.println(b + 1);

THMPR_flag[b] = 2;

}

else if (Ampsrms[b] > (over)) { // over current

Serial.print(" reached overcurrent for phase "); Serial.println(b + 1);



Serial.print(" time in milli seconds since program started, relay has disconnected: ");

Serial.println(start_time);

THMPR_flag[0] = 1; THMPR_flag[1] = 1; THMPR_flag[2] = 1; // setting flags for webpage

}

else if (Ampsrms[b] < (under)) { // under current

Serial.print(" reached under current for phase "); Serial.println(b + 1);



THMPR_flag[0] = 1; THMPR_flag[1] = 1; THMPR_flag[2] = 1; // setting flags for web page

}

else { // the current is equal to the safe current

THMPR_flag[b] = 0;

}

}

}

//---------------------------------------------------------------

//wifi functions

//---------------------------------------------------------------

void check4IP(int t1) //A function to check ip of ESP8266

{

Serial.println("checking IP address of ESP8266...");

int t2 = millis();

while (t2 + t1 > millis())

{

while (Serial1.available() > 0)

{

if (Serial1.find("WIFI GOT IP"))

{

No_IP = true;

}

}

}

}

void get_ip() //After cheacking ip ,this is a function to get IP address

{

Serial.println("getting IP address ...");

IP = "";

char ch = 0;

int h = 0;

while (1)

{

Serial1.println("AT+CIFSR"); //GET IP AT COMMAND, the AT command that gets the

IP adress

Serial.println("AT+CIFSR");

h++;

if ( h > 20) {

Serial.print("sent AT+CIFSR, could not get IP, check wifi connection");

break; // break out of while stat

}


{

if (Serial1.find("STAIP,")) //This finds the STAIP that is the STATIC IP ADDRESS of

ESP8266

{

delay(1000);

Serial.print("IP Address:");


{

ch = Serial1.read(); //Serial1 reads from ESP8266

if (ch == '+')

break;

IP += ch;

}

}

if (ch == '+')

break;

}

if (ch == '+')

break;

delay(1000);

}

Serial.print(IP); //prints IP address in Serial monitor

Serial.print("Port:");

Serial.println(80);

}

void connect_wifi(String cmd, int t) //This function is for connecting ESP8266 with wifi

network by using AT commands

{

int temp = 0, i = 0;

while (1)

{

Serial.println(cmd); //Sends to serial monitor

Serial1.println(cmd); //sends to ESP8266 via serial communication

while (Serial1.available())

{

if (Serial1.find("OK"))

i = 8;

}

delay(t);

if (i > 5)

break;

i++;

}

if (i == 8)

Serial.println("OK");

else

Serial.println("Error");

}

void wifi_init() //This function contains AT commands that passes to connect_wifi()

{

connect_wifi("AT", 100); //Sends AT command with time(Command for

Achknowledgement)

connect_wifi("AT+CWMODE=3", 100); //Sends AT command with time (For setting mode of

Wifi), mode 3 is station and access point

connect_wifi("AT+CWQAP", 100); //Sends AT command with time (for Quit AP)

connect_wifi("AT+RST", 5000); //Sends AT command with time (For RESETTING WIFI)

check4IP(5000);

if (!No_IP)

{

Serial.println("Connecting Wifi....");

connect_wifi("AT+CWJAP=\"DESKTOP-Archer_01\",\"Trialsinspace\"", 7000); // WiFi

username and password here

// Robert's Phone , fuckchina

// Verizon-SM-J327V-9E26\",\"sur3pass

// laptop modile wifi hotspot: DESKTOP-Archer_01 , Trialsinspace

}

else

{

}

Serial.println("Wifi Connected");

get_ip();

connect_wifi("AT+CIPMUX=1", 100); //Sends AT command with time (For creating

multiple connections)

connect_wifi("AT+CIPSERVER=1,80", 100); //Sends AT command with time (For setting

up server with port 80)

}

void sendwebdata(String webPage) //, int pf_max //This function is used to send

webpage datas to the localserver

{

int ii = 0;

while (1)

{

unsigned int l = webPage.length();

Serial.print("AT+CIPSEND=0,");

Serial1.print("AT+CIPSEND=0,");

Serial.println(l + 2);

Serial1.println(l + 2);

delay(100);

Serial.println(webPage); //sends webpage data to serial monitor

// Serial.println(pf_max);

Serial1.println(webPage); //sends webpage data to Serial1 ESP8266

// Serial1.println(pf_max);


{

break;

// }

if (Serial1.find("OK"))

{

ii = 11;

break;

}

}

if (ii == 11) {

break;

}

// if (y >= 6) {

break;

// }

delay(2000);

break;

}

}

void Send() //This function contains data to be sent to local server

{

webpage = "<h1>3phase Microprocessor Relay</h1><body bgcolor=f0f0f0>";

sendwebdata(webpage);

delay(100);

webpage = names;


delay(100);

Serial.print("Sending: ");

for (int b = 0; b <= 2; b++) {

webpage = space;


delay(100);

webpage += "Phase" + String(b + 1) + "";

delay(100);

switch (THMPR_flag[b]) {

case 1:

Serial.println("relay engaged");

webpage = prblm; // relay engaged, overcurrent present

delay(100);


delay(100);

break; // break from for loop

case 2: // approaching the DANGER ZONE

Serial.println("your in the danger zone");

webpage = danger;

delay(100);

sendwebdata(webpage); // , pf_max[1]

delay(100);


default:

Serial.println("operation is normal");

webpage = safe; //operation is normal

delay(100);

sendwebdata(webpage); // , pf_max[1]

delay(100);


}

}

Serial1.println("AT+CIPCLOSE=0"); //Closes the server connection

}

//---------------------------------------------------------------

//hall sensor functions

//---------------------------------------------------------------

float getVPP(int SensorIn) // this function is used to attain the peak to peak voltage of a phase to be

used later

{

float Result;

int readValue; //value read from the sensor

float adcConv = 0.0008058608058608059; // Volts per step


//Serial.println("value from ADC: " + String(analogRead(SensorIn)));

float Value = analogRead(SensorIn) - 1700;// reading input and removing offset

if (SensorIn == PB1) {

Value += 60;

}

Result = (Value * adcConv); // convertting the ADC value into volts

//Serial.println("voltage: " + String(Result));

//Serial.println(" voltage in mV: " + String((Result * 10000) / 2, 3));

return (Result * 10000) / 2; // returns result in mV

}

//---------------------------------------------------------------

void setup() {

//wifi

Serial.begin(9600); //begins serial monitor with baud rate 9600

Serial1.begin(115200); //begins serial communication with esp8266 with baud rate 115200

(Change according to your esp8266 module)

wifi_init();

Serial.println("WiFi System Ready..");

// hall sensor

pinMode(sensorIn[0], INPUT);



//relay

pinMode(Signal[0], OUTPUT);// make more, for more pins



//pinMode(Reset[0], OUTPUT);

//power factor

pinMode(pf_in[0], INPUT);



// frequency measurement

pinMode(freqIn[0], INPUT);


}

void loop() {


for (int b = 0; b <= 2; b++) {

VRMS[b] = getVPP(sensorIn[b]); // copying the array, there are other ways to do this, could

look them up

AmpsRMS[b] = VRMS[b] / mVperAmp; // calculating RMS amperage based upon the type of hall

sensor I'm using

Serial.print(AmpsRMS[b], 2); Serial.print(" Amps RMS, phase"); Serial.println(b + 1);

}

flt_check(AmpsRMS);// sending amps measurement to fault detection, be aware `.20 A offset at

most,from the ac217 hall sensor

getFrequency();

for (int b = 0; b <= 2; b++) {

Serial.print("frequency of phase"); Serial.print(b + 1); Serial.print(": "); Serial.println(Freqs[b]);

}

delay(2000);

//powerfactor();

Serial.println("Please Refresh your Page");


{

if (Serial1.find("0")) // 0,CONNECT

{

Serial.println("Start Printing");

Send();

Serial.println("Done Printing");

delay(1000);

}

break;

}

while (THMPR_flag[0] == 1 || THMPR_flag[1] == 1 || THMPR_flag[2] == 1) { // relay has been

tripped, waiting for reset

Serial.println("relays have been tripped");

// repeats code for the webpage

Serial.println("Please Refresh your Page");


{

if (Serial1.find("0"))

{

Serial.println("Start Printing");

Send();

Serial.println("Done Printing");

}

break;

}

delay(1000);

}

}

4.0 Glossary

Word or Acronym Meaning in This Context

Zero cross detection A method to determine the phase difference between two signals

5.0 Appendix – Reference documents and hardware interface details

Code used in microcontroller:

No. URL

Example:

USB 1.x/2.0 standard pinout

Pin

Name

Cable color

Description 1 VBUS Red +5 V

2 D− White Data −

3 D+ Green Data +

4 GND Black Ground

http://en.wikipedia.org/wiki/Ground_(electricity)

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