help with my UPS problem

[julius64]

ups problem

Hi.
I try to desing a UPS with UPQC topology for non-lineal load, genering a signal with dsPIC30F4011 with modulation PWM in 40kHz, but i have a big problem with noise in output signal in my inverter mosfet when I connect my low pass filter.
My low pass filter is in output of my mosfet full bridge, to make a signal in 50 Hz, as show in this schematic. [/img]
The voltaje output is a 330 Volts, peak (or 220 Volt RMS)
Please help me if exist some error in my circuit or is missing something.
Very thank

 

[sunderwood]

my ups not working

Looks like the bandwidth of your output filter is a little bit too high. I'd recommend increasing that 0.1uF capacitor.
Also, make sure you have some deadtime in your switching commands to prevent shoot through.

 

[masterleous]

pwm 40khz pic16f88

Hi,

It is your capacitor which is not of true value, use a minimum of 2 uf capacitor, however inductor is nominal.

 

[zlatkoMM]

50hz transformer pwm

I must ask --WHY is this topic allways on top?????????????????

 

[Audioguru]

You want to filter the output of the transformer, not its input.
The transformer needs to be a high frequency ferrite one to pass the 40kHz PWM Then the filter at the output smooths the PWM into a 50Hz sine-wave.

 

[Johansen]

only the inductor needs to be ferrite. the transformer 'sees' 50hz.

that .1 uf cap needs to be 10-30 times the value.

 

[fsmyth]

Check here:
**broken link removed**
There are a few examples of power filters; will be adding more
soon.
<als>

 

[Audioguru]

Why use a huge, heavy and expensive 50Hz transformer when the circuit has 40kHz PWM?

 

[rauol]

i dont think the L and C at the input of the transformer is required, the hi-frequency component will be filtered by the primary inductance of the main transformer itself, maybe only a small capacitor will be required at the output.
by the way is it a closed loop system?

 

[ziaulislam]

I THINK IT IS BATER TO FILTER HIGH

FREQUENCY AT OUT PUT IF YOU CAN’T GET SUITABLE 40K FERRITE

TRANSFORMER YOU CAN TRAY TRANSFORMER USED IN COMPUTER POWER

SUPPLY AND YOU CAN ALSO GET COMPONENTS FOR FILTER FROM

THERE.

 

[krish2487]

hi
i am a EEE student working on a similar UPS project.
except i am working on a PIC16F series than dsPIC

can we swap info on the schematic and code ??
it will be helpful for both..
thank you..

Added after 10 minutes:

1. the switching activity of the power devices generates spikes.
2. this needs to be filtered using an appropriately calculated integrating filter.
3. In this case the capacitor Cx 0.1uf needs to be raised to 2 uf .
4.Use a appropriate type such as polyester film and foil capacitor which can withstand high peak currents.
5. Try FF06 of ALCON(india) or PPPRRB series capacitors from CTR(india)