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| Sine wave inverter |
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| NASK:
i need to utilize sine wave inverter, here i go with 50Hz/ Vp=4V sine wave and 500Hz/ Vp=5V triangle wave and it gave to 741 to generate PWM signal. out put is Capture1.PNG when i going to increase triangle wave frequency to 1KHz it out put is Capture2.PNG i think 1KHz signal is not making required PWM Pulses and need to clarify 500Hz triangle wave ,is it enough to this type of designs. Furthermore, I add a H-Bridge and a transformer (pri 100mH, sec 10mH,) as following Capture4.PNG and its out put is Capture3.PNG i need to Utilize 230V,50Hz ,5A max sine wave inverter, Am I missing some steps to do this? |
| David Hess:
The 741 is too slow to be used as a pulse width modulator. Operational amplifiers are not really suited for this application and a comparator should be used instead. |
| Audioguru:
50 years ago the designers of the lousy old 741 opamp did not dream that anybody would use it for Pulse-Width-Modulation. Its slew rate is 1/10th the speed of ordinary modern opamps. When a comparator is supposed to be used then don't use an opamp. |
| firewalker:
If you are a beginner it would be easier to use a center tap transformer and drive it with two n-channel low side mosfets. Alexander. |
| NASK:
thanks for support, adding LM111 comparator able to increase triangle wave to 10kHz and made a pwm. Capture2 but i need pwm pulses in both positive and negative sides like Capture1 in my reference pdf( http://www.ti.com/lit/an/slaa602a/slaa602a.pdf) it did through this circuit Capture3. its non inverting input connected through like "not gate " i think its not possible, then how to make this circuit. |
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