AC Frequency conversion in SMPS

[mitz]

How is High frequency AC (in KHz / MHz) is converted to 50Hz AC in UPS or SMPS?

What role does the toroid inductor do in UPS?

Am I right that the SMPS converts DC to HF AC then to 50Hz AC?

Thanks.

 

[phobos1]

Hello mitz did u find out the answer, now i'm in need of the same. can u please tell me how toroid is used for switching the current in smps also in electronic ballast if possible please post any links.. thanks

 

[mitz]

Hello mitz did u find out the answer, now i'm in need of the same. can u please tell me how toroid is used for switching the current in smps also in electronic ballast if possible please post any links.. thanks

@phobos1. I'm yet to find the answer. Bit busy with work. You can check this link. Has many useful topics including smps.

https://tahmidmc.blogspot.in/p/blog-page.html

 

[Fadi Mkhayel]

what are you talking about, that is a total insane. In ups, a50hz modified sine wave signal is generated which is a square wave alternating between -220v and 220v and having one additional voltage level which is zero. The role of the torroid is to shape filter some of the modified sine wave harmonics.
Regards.

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what are you talking about, that is a total insane. In ups, a50hz modified sine wave signal is generated which is a square wave alternating between -220v and 220v and having one additional voltage level which is zero. The role of the torroid is to shape filter some of the modified sine wave harmonics.
Regards.

 

[ashugtiwari]

a very basic answer:
The kHz or MHz signal u r talking about is a square wave oscillating at 50% duty cycle. For eg. a sine wave is calculated for particular freq (specially line freq of 50/60Hz) in digital domain for a single period or cycle which is in range of 0 to 1 values. The output is then converted to integer values by multiplying by some high integer value to maintain the higher resolution. The values then change the duty cycle of that kHz or MHz wave from 0% to 100% at very high resolution, This will switch on and off power devices like SCR or triacs, which passes its o/p to an toroidal inductor (sometimes with capacitor to form resonant circuit at 50Hz) which filters the modulated kHz or Mhz signal which is called PWM. The filtering happens at cut off of 70 to 80 Hz to generate 50Hz line sine wave, which is nothing but inverter principle converting DC to AC.
For this purpose MCU's used to generate high resolution PWM at very high sampling rate which is PWM freq. I have seen one using PIC MCU.
A toroidal coil is very high inductance inductor in a very small size with very small magnetic losses, thats why its used to provide or boost the o/p current. The big capacitor is used to provide high voltage.

In short, 50Hz sine wave generated digitally at very high sampling rate then PWM at very high freq (= sampling rate freq) is used to convert digital signal to analog using toroid coil and capacitor resonator circuit which is nothing but filtering of PWM. (its something too detailed to explain here, thats why answer is little vague) to generate 50Hz line freq.

check this link to understand SMPS in details: https://www.youtube.com/watch?v=nmUug3WNIZI

hope that helps.

 

[mitz]

@ ashugtiwari. Thank you very much for the excellent reply.