#### fadhel93

##### Newbie level 4

Greetings.

Trying to make a sine wave inverter.

Sinusoidal PWM, an mbed driving an H-bridge with two IR2186 at 20KHz

the outputs from the mbed are clear half sinewaves but the output without the filter has distortions every cirtain time

(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

the outputs from the mbed are clear half sinewaves but the output without the filter has distortions every cirtain time

(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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