What is a Power inverter
A power inverter, or inverter, is a power electronic device or circuitry that changes direct current (DC) to alternating current (AC).
The input voltage, output voltage and frequency, and overall power handling depend on the design of the specific device or circuitry. The inverter does not produce any power; the power is provided by the DC source.
Different Types of Inverters
- Sine Wave
- Modified Sine Wave
- Square Wave.
There are 3 major types of inverters – sine wave ( “true” or “pure” sine wave), modified sine wave (actually a modified square wave), and square wave.
1;Sine Wave
A sine wave is what you get from your local utility company and (usually) from a generator. This is because it is generated by rotating AC machinery and sine waves are a natural product of rotating AC machinery. The major advantage of a sine wave inverter is that all of the equipment which is sold on the market is designed for a sine wave. This guarantees that the equipment will work to its full specifications. Some appliances, such as motors and microwave ovens will only produce full output with sine wave power. A few appliances, such as bread makers, light dimmers, and some battery chargers require a sine wave to work at all. Sine wave inverters are always more expensive – from 2 to 3 times as much.
2;Modified Sine Wave
A modified sine wave inverter actually has a waveform more like a square wave, but with an extra step or so. A modified sine wave inverter will work fine with most equipment, although the efficiency or power will be reduced with some. Motors, such as refrigerator motor, pumps, fans etc will use more power from the inverter due to lower efficiency. Most motors will use about 20% more power. This is because a fair percentage of a modified sine wave is higher frequencies – that is, not 60 Hz – so the motors cannot use it. Some fluorescent lights will not operate quite as bright, and some may buzz or make annoying humming noises. Appliances with electronic timers and/or digital clocks will often not operate correctly. Many appliances get their timing from the line power – basically, they take the 60 Hz (cycles per second) and divide it down to 1 per second or whatever is needed. Because the modified sine wave is noisier and rougher than a pure sine wave, clocks and timers may run faster or not work at all. They also have some parts of the wave that are not 60 Hz, which can make clocks run fast. Items such as bread makers and light dimmers may not work at all – in many cases appliances that use electronic temperature controls will not control. The most common is on such things as variable speed drills will only have two speeds – on and off.
3;Square Wave
There are very few, but the cheapest inverters are square wave. A square wave inverter will run simple things like tools with universal motors without a problem, but not much else. Square wave inverters are seldom seen anymore.
Input voltage
A typical power inverter device or circuit requires a relatively stable DC power source capable of supplying enough current for the intended power demands of the system. The input voltage depends on the design and purpose of the inverter. Examples include:
- 12 V DC, for smaller consumer and commercial inverters that typically run from a rechargeable 12 V lead acid battery or automotive electrical outlet
- 24, 36 and 48 V DC, which are common standards for home energy systems.
- 200 to 400 V DC, when power is from photovoltaic solar panels.
- 300 to 450 V DC, when power is from electric vehicle battery packs in vehicle-to-grid systems.
- Hundreds of thousands of volts, where the inverter is part of a high-voltage direct current power transmission system.
The main difference between the two types of power inverter configurations
The main difference between the two configurations is that the output voltage of full bridge inverter is equal to the power supply voltage while output voltage for the half bridge inverter is equal one half of the power supply voltage. Since the output power is proportional to the square of the voltage then the output power of the full bridge will four times of that of the half bridge. This would be enable operation of the amplifier at lower voltage to get the same power which will reduce the size of the battery.
- So, from this point of view the full bridge will be preferred.