What type of current does your solar system produce?

26/7/2019

Let us say you have installed a solar power system at your rooftop and right now you are enjoying the air of a fan, powered by the solar panels.
Have you ever imagined the type of energy conversions going on within the system?

Principle of solar power system

Let me re-iterate the energy law, it states that the energy can neither be created nor destroyed but can be converted from one form to another.
In this particular case, the sunlight is converted into electrical energy by the solar panels and this electrical energy is further converted into mechanical (rotational energy) energy by the motor fitted inside the fans, hence giving you air.
Within the above conversion pattern, one more conversion is going on within electrical energy itself. Its direct current to alternating current and the inverter does this job.

Alternating current vs Direct current

The main reason for this conversion is that our electrical appliances are tuned to alternating current and cannot run on direct current.
Although both are the types of current, the basic difference between the two is that one has constant value and flows in one direction called direct current while another change/reverses its direction periodically, alternating between the minimum to the maximum, called alternating current.
You know our engineers are very intelligent people, they designed a.c. tuned appliances because they have certain advantages over D.C.:

It is easier and cheaper to produce a.c. than d.c.
The loss of energy during energy transmission is very less in a.c.
The a.c. current can easily be step-up and step- down using transformers and the energy loss in this process is minimum

Some other forms of alternating current:

Types of alternating current

How alternating current is produced?

The teachers told you that current completes the whole circuit to let the lamp glow. She was talking about the direct current then.

Then how does the alternating current make bulb glow because it does not flow in one direction but makes a to-and-fro motion?

The to-and-fro motion of the alternating current vibrates the filament of the bulb resulting in heat production which makes the bulb glow.

But the question is still unanswered that how alternating current is produced?

If I draw a simple circuit of a battery connected to a resistor with a tapping key for connecting and disconnecting the current supply.

If I manually start tapping the key very fast then the moment, I close the key, the current will flow through the circuit and it reduces to zero when I release the key. The current waveform formed will be something like shown above in the picture.

But still, it doesn’t validate the to-and-fro motion of the alternating current.

A simple resistive circuit with one key

Let us draw another circuit:

A resistive circuit with 4 keys

When key 1 and key 3 are closed, the current will flow from A to B And the waveform produced will be as follows:

The flow of current is from A to B

When key 2 and key 4 are closed, the direction of current reverses and it flows from B to A:

The direction of current reverses. Now it flows from B to A

Now if I combine the two wave-forms, it will look like as follows:

The waveform formed in one complete cycle

The sine wave inverter

If I can switch this arrangement alternately then I am producing alternating current. And if I’m fast enough to switch this arrangement 50-60 times in 1 second then I’m producing an alternating current of 50 Hz- 60 Hz frequency similar to what we get in our households.

The arrangement in the inverter is not different what we have discussed above but it has a more sophisticated design of producing alternating current.

The oscillator converts direct current to alternating current. Now the alternating current produced is of low intensity which cannot drive the main coil. Therefore, this current is needed to be amplified and the amplifier does this job.

Conclusion

The solar panel converts solar energy into direct current and it is the inverter which converts direct current or voltage into alternating current or voltage to run our electrical appliances.

So, the solar power system as a whole produce alternating current as the output.

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