Output frequency problem in inverter

[Bindu boora]

Hey folks,

I used inverter switching frequency of 50khz.It is connected to LC filter.But what ever L and C values I use ,the output frequency is only 2000hz.Im using this in matlab.How to rectify this?.Please give the reason.

 

[KlausST]

Hi,

What else do you expect?

A filter can only attennuate a signal, but not cancel.

Also we don't know your schematic, your code, your filter characteristic, your filter cutoff frequency...

How can we help?
--> give complete informations

Klaus

 

[Bindu boora]

This circuit im

Hi,

What else do you expect?

A filter can only attennuate a signal, but not cancel.

Also we don't know your schematic, your code, your filter characteristic, your filter cutoff frequency...

How can we help?
--> give complete informations

Klaus

Hi,

What else do you expect?

A filter can only attennuate a signal, but not cancel.

Also we don't know your schematic, your code, your filter characteristic, your filter cutoff frequency...

How can we help?
--> give complete informations

Klaus

This circuit im trying to simulate in matlab.I used 50khz pulse generator,50v dc source,transformer of 10khz 1:4 transformer ratio.And the total output should be a dc component of 200V.

Inverter + lc filter is giving sine output but if amplitude of output is less frequency is also less...i want more frequency and if i change l and c values to get higher frequency the amplitude is getting high and sine wave is getting some distortions

 

[BradtheRad]

Your schematic has several inductors and capacitors in a position where they may combine and develop resonant action. Can one of those frequencies be 2 kHz?
Furthermore any of those LC combinations can interact with another LC combination to create other frequencies (or perhaps double your original 1 kHz).

I'm running a simulation of your setup. L1 C1 appears to send a sine wave to the transformer. The secondary produces a smooth sinewave 1kHz. Is there any reason you can't put a conventional power supply at the secondary side? Made from a simple diode bridge and capacitor?

 

[Bindu boora]

Yeahh...I

Your schematic has several inductors and capacitors in a position where they may combine and develop resonant action. Can one of those frequencies be 2 kHz?
Furthermore any of those LC combinations can interact with another LC combination to create other frequencies (or perhaps double your original 1 kHz).

I'm running a simulation of your setup. L1 C1 appears to send a sine wave to the transformer. The secondary produces a smooth sinewave 1kHz. Is there any reason you can't put a conventional power supply at the secondary side? Made from a simple diode bridge and capacitor?

Yeah..I want a non pulsating dc at the output...not pulsating dc...I tried other ways finally got a sine wave the other end and by filters i got non pulsating output voltage but now the problem is the current the circuit is very less...because of which for less values of R the output voltage is very less...The output voltage is increasing by increase in R.But i want more current at less values of R.Please can you tell me what are other ways of increasing current in circuit not by varying input voltage or load value R

 

[I_think]

This circuit im




This circuit im trying to simulate in matlab.I used 50khz pulse generator,50v dc source,transformer of 10khz 1:4 transformer ratio.And the total output should be a dc component of 200V.

Inverter + lc filter is giving sine output but if amplitude of output is less frequency is also less...i want more frequency and if i change l and c values to get higher frequency the amplitude is getting high and sine wave is getting some distortions
View attachment 163258

Try removing L1 & C1. See what you get. the switching frequency Should be such that the core should work as LPF. This is what typically done with home sine-wave inverters. I will share the Module (IC) here If I find it. for reference.

Found One more hint. Refer EGS003.

 

[BradtheRad]

other ways of increasing current in circuit

Possibly there is excess parasitic resistance in components. A different frequency may be better suited for your transformer construction.

The more components are in your system, the more components can cause losses due to parasitic resistance, etc.

Your project appears to be dc-to-dc conversion. If you were to consider a different topology you might reduce parts count, making it easier, simpler, more efficient, and better at providing your power needs.

It is when you must handle true bipolar alternating current, that the H-bridge and LLC and transformer topology is more useful.

 

[KlausST]

Hi,

For me it still is unclear what you want to achieve.
To me it seems you use the wrong topology.

You still miss to provide clear informations regarding code and drive signals.
Thus there may be many reasons.

The terminology "inverter" often is used when one wants to generate a new (fundamental) frequency to drive AC loads, like motors or transformers.
But for DC-DC converters this is not useful. For DC-DC converters one often generates high frequency square wave (non sinusoidal) signals to directly drive a HF transformer, then a rectifier and filter.

Klaus