Hello everyone! I have a VSI SPWM Inverter Project, but my supervisor ask me to upgrade it to a VFD Inverter. I've found a code about how to generate 3 phase SPWM in this article. It provides 6 SPWM outputs, and i think i need to invert 3 SPWM output to negative signals. Then someone told me that i can invert the lookup table or PWM, so the output will act as negative signals, but the other one told me that arduino can't generate negatives signal. So, i haven't find any methods to invert 3 SPWM signals. The output signal is so smooth. And i also need to improve the code to VFD code with range frequency 0-100 Hz. I've found a reference about VFD from this one and tried to modify the SPWM code, but failed. I have a Custom Gate Driver, a MOSFET bridge with IRFP460 MOSFET, then LC Low Pass Filter for each phase between Arduino Mega and 3 Phase Induction Motor. Right now, i can only provide MOSFET bridge schematic and 3 Phase Motor plate in attachment, because i accidentally deleted the gate driver schematic, but the gate driver output is 10 vdc and i think that's enough to provide IRFP460 MOSFET gate.The reason i haven't use the VFD code from the github is i want to learn how to implement and understand the code, not just simply using it in my project. Anyway, i don't think this VFD code works in my VSI circuit that i've built. Could anyone help me to invert 3 SPWM signals and improve the code to VFD Inverter, please? Here is the SPWM code..
int i=0;
int j=0;
int k=0;
int x=0;
int y=0;
int z=0;
int OK=0;
int OK1=0;
int OK2=0;
int OK3=0;
int OK4=0;
int sinPWM[]={1,2,5,7,10,12,15,17,19,22,24,27,30,32,34,37,39,42,
44,47,49,52,54,57,59,61,64,66,69,71,73,76,78,80,83,85,88,90,92,94,97,99,
101,103,106,108,110,113,115,117,119,121,124,126,128,130,132,134,136,138,140,142,144,146,
148,150,152,154,156,158,160,162,164,166,168,169,171,173,175,177,178,180,182,184,185,187,188,190,192,193,
195,196,198,199,201,202,204,205,207,208,209,211,212,213,215,216,217,219,220,221,222,223,224,225,226,227,
228,229,230,231,232,233,234,235,236,237,237,238,239,240,240,241,242,242,243,243,244,244,245,245,246,246,
247,247,247,248,248,248,248,249,249,249,249,249,255,255,255,255,249,249,249,249,249,248,
248,248,248,247,247,247,246,246,245,245,244,244,243,243,242,242,241,240,240,239,238,237,237,236,235,234,
233,232,231,230,229,228,227,226,225,224,223,222,221,220,219,217,216,215,213,212,211,209,208,207,205,204,
202,201,199,198,196,195,193,192,190,188,187,185,184,182,180,178,177,175,173,171,169,168,166,164,162,160,
158,156,154,152,150,148,146,144,142,140,138,136,134,132,130,128,126,124,121,119,117,115,113,110,108,106,
103,101,99,97,94,92,90,88,85,83,80,78,76,73,71,69,66,64,61,59,57,54,52,49,47,44,42,39,37,34,32,30,
27,24,22,19,17,15,12,10,7,5,2,1};
void setup() {
Serial.begin(9600);
pinMode(4, OUTPUT);
pinMode(13,OUTPUT);
pinMode(9,OUTPUT);
pinMode(10,OUTPUT);
pinMode(2,OUTPUT);
pinMode(3,OUTPUT);
pinMode(5,OUTPUT);
cli();// stop interrupts
TCCR0A=0;//reset the value
TCCR0B=0;//reset the value
TCNT0=0;//reset the value
//0b allow me to write bits in binary
TCCR0A=0b10100001;//phase correct pwm mode
TCCR0B=0b00000001; //no prescaler
TCCR2A=0;//reset the value
TCCR2B=0;//reset the value
TCNT2=0;//reset the value
//0b allow me to write bits in binary
TCCR2A=0b10100001;//phase correct pwm mode
TCCR2B=0b00000001; //no prescaler
TCCR3A=0;//reset the value
TCCR3B=0;//reset the value
TCNT3=0;//reset the value
//0b allow me to write bits in binary
TCCR3A=0b10100001;//phase correct pwm mode
TCCR3B=0b00000001; //no prescaler
TCCR1A=0;//reset the value
TCCR1B=0;//reset the value
TCNT1=0;//reset the value
OCR1A=509;// compare match value
TCCR1B=0b00001001; //WGM12 bit is 1 for CTC mode and no prescaler
TIMSK1 |=(1 << OCIE1A);// enable interrupts
sei();//stop interrupts
}
ISR(TIMER1_COMPA_vect){// interrupt when timer 1 match with OCR1A value
if(i>313 && OK==0){// final value from vector for pin 13
i=0;// go to first value of vector
OK=1;//enable pin 4
}
if(i>313 && OK==1){// final value from vector for pin 4
i=0;//go to firs value of vector
OK=0;//enable pin 13
}
x=sinPWM[i];// x take the value from vector corresponding to position i(i is zero indexed)
i=i+1;// go to the next position
if(OK==0){
OCR0B=0;//make pin 4 0
OCR0A=x;//enable pin 13 to corresponding duty cycle
}
if(OK==1){
OCR0A=0;//make pin 13 0
OCR0B=x;//enable pin 4 to corresponding duty cycle
}
if ((i==209) || OK1==1){//if i equal with 209 enable second signal
OK1=1;//mantain if function
if(j>313 && OK2==0){// final value from vector for pin 10
j=0;// go to first value of vector
OK2=1;//enable pin 9
}
if(j>313 && OK2==1){// final value from vector for pin 9
j=0;//go to firs value of vector
OK2=0;//enable pin 10
}
y=sinPWM[j];// y take the value from vector corresponding to position j(j is zero indexed)
j=j+1;// go to the next position
if(OK2==0){
OCR2B=0;//make pin 9 0
OCR2A=y;//enable pin 10 to corresponding duty cycle
}
if(OK2==1){
OCR2A=0;//make pin 10 0
OCR2B=y;//enable pin 9 to corresponding duty cycle
}
}
if ((j==209) || OK3==1){//if j equal with 209 enable third signal
OK3=1;//mantain if function
if(k>313 && OK4==0){// final value from vector for pin 5
k=0;// go to first value of vector
OK4=1;//enable pin 2
}
if(k>313 && OK4==1){// final value from vector for pin 2
k=0;//go to firs value of vector
OK4=0;//enable pin 5
}
z=sinPWM[k];// z take the value from vector corresponding to position k(k is zero indexed)
k=k+1;// go to the next position
if(OK4==0){
OCR3B=0;//make pin 2 0
OCR3A=z;//enable pin 5 to corresponding duty cycle
}
if(OK4==1){
OCR3A=0;//make pin 5 0
OCR3B=z;//enable pin 2 to corresponding duty cycle
}
}
}
void loop() {
}
