IR2104, Full H-bridge SPWM using Arduino

[imranahmed]

Hi, I making SPWM inverter using Arduino, IR2104 and Full H-bridge, it is giving good output but output have ripples or SPWM component, please let me know why it is appearing in output and how to rectify?. In the mean time, I am using wave generator to generate SPWM signals.

Switching Frequency = 20kHz
Fundamental Frequency = 50Hz
Cutt-off Frequency = 1591.5 Hz

 

[KlausST]

Hi,

if I wanted to see what happens ... I´d surely have a look at the PWM signals.. along with the sine.
You have a scopoe - so use it.

Klaus

 

[imranahmed]

Please find attachment. SPWM signals at output of H-bridge

 

[KlausST]

Hi,

.. along with the sine.

.. no sine here.

You have chosen to show the bridge outputs... My bad, I wasn´t clear about it, but I meant the bridge inputs. Anyways you can see that it stalls.
--> So correct your SPWM generation to overcome this problem.

***
But I´ve just recognized a different problem.
What you showed in post#1 scope picture is NOT the output you wanted to show/see.

the load is the resistor --> thus you need to show the voltage across the resistor.
And since the resistor is not connected to GND you need to measure the voltage in differential mode: V_right_leg - V_left_leg

I´m not familiar with your simulation tool ... but I expect the scope to be able to show differential signals.

Klaus

 

[imranahmed]

Hi,


.. no sine here.

You have chosen to show the bridge outputs... My bad, I wasn´t clear about it, but I meant the bridge inputs. Anyways you can see that it stalls.
--> So correct your SPWM generation to overcome this problem.

Now, I attach 4 inputs of H-bridge waveform, please see.

***
But I´ve just recognized a different problem.
What you showed in post#1 scope picture is NOT the output you wanted to show/see.

the load is the resistor --> thus you need to show the voltage across the resistor.

I connected scope on center point of LC filter means, after Inductor and across Capacitor, is it not?
OR how to show voltage across resistor.

And since the resistor is not connected to GND you need to measure the voltage in differential mode: V_right_leg - V_left_leg

I´m not familiar with your simulation tool ... but I expect the scope to be able to show differential signals.

WOW!!! When I measured across Resistor so it will be sine wave WOW please find in attachment.

Klaus

 

[imranahmed]

Please let me know is there any changes required in my circuit?

 

[KlausST]

Please let me know is there any changes required in my circuit?

... still the same as marked in post#4 with "-->"

****
In addition to this: Is there still something that worries you?
It´s your circuit. You need to decide your targets, you need to be satisfied.

Klaus

 

[imranahmed]

... still the same as marked in post#4 with "-->"

In post#4, you said about correction of SPWM generation. I generate it using 2 signal generators, one generate sinewave 50Hz 12V and second generate triangular wave as carrier at 20kHz 12V then I mixed both using comparator and its output and its compliment feed into 2 IR2104 mosfet driver then goes to Full H-bridge. Is there any correction needed?.

****
In addition to this: Is there still something that worries you?
It´s your circuit. You need to decide your targets, you need to be satisfied.

I am satisfied but some worry about SPWM generation.

Klaus

 

[KlausST]

Hi,

I alread wrote.

Anyways you can see that it stalls.
--> So correct your SPWM generation to overcome this problem.

I mean .. you see the PWM is NOT CONTINOUS. This is what I called "stalled".

If you are fine with it .. then keep it.
If you want it to be more perfect ... then modify it.
I can´t make this decision for you.

What I would do:
Read the comparator datasheets. Check all signals whether they are within specification.
The same I recommend to you.

I don´t know your goals. I can not know whether this simulation is a school task .. or you want to build "something that works" for your owwn, or you want to do a high precision, high reliable industrial mass product.
Indeed I don´t need to know this: It´s your job (ideally the first job) to decide your goals, your budget, your requirements, your specifications. .. and do the design according this.

Klaus

added:

--- Updated Today at 2:18 PM ---

I am satisfied but some worry about SPWM generation.

"some worry" .. exactly means what?