An electricity inverter converts DC power, typically from batteries such as those in solar panels or gas generators into AC power. It can then be used to run a wide variety of different appliances from a battery-based system or plugged into a conventional electrical wall outlet.
Inverters are a vital part of the modern, renewable powered grid. They allow you to connect solar power directly to the grid so that you can use your local energy source when the electricity goes down.
Unlike the traditional AC wall socket, which operates at 60 hertz and provides direct current, an inverter uses a series of pulses to produce the AC you need. This is done by a circuit called PWM, or Pulse Width Modulation, which switches on and off power MOSFETs in a way that creates a modified sine wave.
Some inverters are designed to run from a single 12 volt or 24 volt battery while others have built-in batteries so they can function in standalone mode. The type of inverter you choose depends on what you want to do and how long you plan on using it.
You can also connect multiple 12 volt batteries in a parallel configuration to give you a longer time between charges. If you plan on running your appliances for a few hours at a time, this is a good option.
Electricity inverters come in a wide range of shapes and sizes. Some are small enough to fit in a cigarette lighter socket. Some are large and bulky, but they still pack plenty of power and can easily be plugged into a standard wall outlet.
Most inverters will convert about 100 watts of DC to about 50 watts of AC power, but some will go much further. If you plan on using your inverter to charge a laptop computer, for example, it’s a good idea to find one that can handle at least 125 watts of input power.
Inverters can be very complex to operate, and they generate a lot of heat as well. It’s important to look for a unit with an appropriate heat sink and cooling fan.
Typical inverter designs include a microprocessor that rapidly switches on and off power MOSFETs to produce a modified sine wave signal. This topology can be used to reduce the size of an inverter while producing a high-quality output.
Some inverters also use a high-frequency core-based transformer to step down the voltage of an AC source. This is a popular design in adjustable speed drive applications because it can avoid extra clamping diodes and voltage balancing capacitors, which can be costly to add.
Other inverter designs use a switched reluctance circuit to convert DC power to AC. This is a very efficient type of circuit, but the number of steps needed to re-create a reference sinusoidal voltage can be expensive.
The earliest forms of inverters were rotary converters and motor-generator sets (M-G sets). Later vacuum tubes, such as thyratron and gas filled tubes, were used to switch between DC and AC circuits. However, semiconductors such as transistors and IGBTs have now become the preferred switching components for most inverter circuits because they offer better voltage and current ratings.
