fadhel93
Newbie level 4
![Newbie level 4](/styles/images/ranks/blevel1.gif)
Greetings.
Trying to make a sine wave inverter.
Sinusoidal PWM, an mbed driving an H-bridge with two IR2186 at 20KHz
![gate.jpg gate.jpg](https://www.edaboard.com/data/attachments/53/53919-a16cffce29f12f5e359dc7cb570f07a5.jpg)
![gate1.jpg gate1.jpg](https://www.edaboard.com/data/attachments/53/53920-58a52196283be7dc741aca653a8a224e.jpg)
the outputs from the mbed are clear half sinewaves but the output without the filter has distortions every cirtain time
![DSC_1291.jpg DSC_1291.jpg](https://www.edaboard.com/data/attachments/53/53921-3eb48b7ea69646d60161cb60441e3f06.jpg)
![DSC_1292.jpg DSC_1292.jpg](https://www.edaboard.com/data/attachments/53/53922-037ef30bba51c2244be0c88886f713f1.jpg)
(the code)
what could be the problem
Trying to make a sine wave inverter.
Sinusoidal PWM, an mbed driving an H-bridge with two IR2186 at 20KHz
![gate.jpg gate.jpg](https://www.edaboard.com/data/attachments/53/53919-a16cffce29f12f5e359dc7cb570f07a5.jpg)
![gate1.jpg gate1.jpg](https://www.edaboard.com/data/attachments/53/53920-58a52196283be7dc741aca653a8a224e.jpg)
the outputs from the mbed are clear half sinewaves but the output without the filter has distortions every cirtain time
![DSC_1291.jpg DSC_1291.jpg](https://www.edaboard.com/data/attachments/53/53921-3eb48b7ea69646d60161cb60441e3f06.jpg)
![DSC_1292.jpg DSC_1292.jpg](https://www.edaboard.com/data/attachments/53/53922-037ef30bba51c2244be0c88886f713f1.jpg)
(the code)
Code C - [expand] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 /* ********************************************************* * Fadhel Ali 201102569 * * DC to AC Inverter * ********************************************************* */ #include "mbed.h" #include "QEI.h" #define size 512 #define ph50Hz 4400 #define pi 3.14159265 PwmOut out(p21); PwmOut out1(p22); PwmOut out2(p23); PwmOut out3(p24); QEI wheel (p15, p16, NC, 16); DigitalIn switch1 (p19); DigitalOut base(p30); int main() { out.period_us(50); float sin1[size],sin2[size],sin3[size],sin4[size]; float omega; int x=0; int y; int n, z=0; base = 0; for (int i=0; i<size; i++) { //fill the arrays with the sine wave's amplitude values omega= 2*pi*i/float(size); sin1[i]=(sin(omega));//half-wave rectified signal sin2[i]=(sin(omega+pi));//180 deg phase so each phase will not work togother sin3[i]=(sin(omega)); sin4[i]=(sin(omega+pi)); } wheel.reset(); n=ph50Hz; while (1) { z=wheel.getPulses()*100; //read the state of the shaft encoder x+=n+z; y=(x>>14) & (size-1); //controls the frequency //call the sine wave arrays out=sin1[y]; out1=sin2[y]; out2=sin3[y]; out3=sin4[y]; } }
what could be the problem
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