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Inverter for alternating current fruition

Published : 07/16/2018 10:07:02
Categories : Photovoltaic Panels

An inverter is a fundamental component that powers an electrical load in alternating current or that enters alternating current in the system. It is used to transform the direct current voltage of batteries (12V-24V) in alternating voltage (230V). The operating principle of an inverter is very simple: it uses the normal voltage a caravan battery (12V) and provides an alternated outlet at 23V.

Which typology of inverter?

In order to choose the inverter most appropriate to your needs you should ask yourself which applications you need to power. For example, an inverter that works in a pure sine wave can power every device that can be powered by line voltage, while this not possible with an inverter with a modified wave.


Inverters which are more complex and expensive produce a kind of outgoing wave that is generally sine and that does not damage other advices. These are indicated to provide energy to every equipment with high sensitivity that require this kind of wave in order to work. Motor equipments are made to work with a sine voltage.

Modified waves are squared and they get blunted and produced by cheap inverters, with the possible risk to damage connected devices. This risk depends on the sensitivity of the device itself.

In pure sine wave inverters, the second stage is more complex, the 300V voltage of the first stage gets modulated by impulses (PWM) at very high filtered sequence. The result is that in outgoing you have a sine voltage which quality is often superior to line voltage.

But what does it mean?

Firstly, motor equipments are constructed to work with a sine voltage and they get damaged if powered by a square wave, so if you need to power something that is composed by an engine (fridge, grinding wheel, drill, etc.) you have to use a pure sine wave.

A lot of others advices could have problems if powered by a not sine wave, such as Hi-Fi players, dimmer lamps, advices that use transformers in powering, etc.

What you can commonly notice in audio devices is a hum caused by the harmonics from the entering square wave.

Now, what can we power with a modified sine wave?

Theoretically, everything that provides a switching input could be powered by a modified sine wave (televisions, laptops, chargers, etc.) but we must say that these advices are projected to work with a sine voltage and they are tested with it. Powering them with something that is not sine, unless it is explicitly required by the instruction manual, could cause damages.

Why should you buy a modified wave instead of a pure one?

In the event of specific performance requirements or utilisation of devices without engine, because a pure wave inverter can power every device that can be powered by line voltage, while a modified wave inverter is not able to do that.


This kind of inverter is conceptually composed by two stages, the first one elevates the voltage from 12V to a 300V voltage. This voltage – in simpler inverters and usually cheaper ones, are also called “by modified sine wave” or “pseudo-sine” – simply gets modulated by two digital signals, one of them controls the polarity and the other one the presence of the outgoing voltage. The result is that in outgoing you have something more similar to a squared wave than sine one.

The form of a modified sine wave is in steps, studied in order to have a wave similar to the “pure sine” one of the electric domestic line. This kind of wave is appropriate to provide the energy necessary to the majority of electric and electronic applications/equipments such as incandescent lamps, radios, computers, notebooks, televisions, video recorders, video games, microwaves, etc.

The modified sine wave is definitely better than the squared provided by others inverters on the market.

Which power do you need?

The essential factor in the choice of an inverter is the output power, expressed in watt that is continually provided, knowing in advance which and how many equipments will be connected to the inverter and this will be chosen according to the capacity to emit a slightly superior power compared to the one required by the utilisation.

Various equipments can be connected to the same inverter: the total addition of the power required by every advice must not overcome the maximum emitted power and insertion current by power consumers must be able to be covered from the maximum power of the inverter.

In the event you want to power electric engines, fridges etc. that usually have a high absorption during the start-up phase, you will need an inverter that in the cue phase emits a double or triple power than the normally required by equipments. The grief for not doing this will be that the engine will not start-up and the inverter will get blocked.

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