What does an Inverter do?

What is an inverter?

An inverter or power inverter is a device that converts the direct current (DC) to alternating current (AC) at the required frequency and voltage output. The inverter might be worked as an independent equipment for applications, such as, solar power, or as a backup power supply from batteries which are charged separately. The other configuration is at which it is a part of a bigger circuit, for example, a power supply unit, or a UPS. In this situation, the inverter input DC is from the rectified mains AC in the PSU, while from either the rectified AC in the UPS when there is a power and from  the batteries when there is a power failure.

There are various kinds of inverters based on the shape of the waveform. These have varying by circuit designs, efficiencies, advantages and disadvantages. A simple and common use of inverter is the solar inverter. It converts direct current (DC) from a PV solar panel to alternating current (AC) that can be fed into the electrical grid. The AC power is used for home appliances.

Type of inverters

According to the output characteristics, there are three types of inverters:

Square Wave Inverter, Sine Wave Inverter, Adjusted Sine Wave Inverter

1) Square wave inverter

The output waveform of the voltage for this inverter is a square wave. This kind of inverter is least utilized among other sort of inverter because all appliances are intended for sine wave supply. If we supply square wave to sine wave based appliances, it might be damaged. Square wave inverter is extremely low cost inverter but the application is rare. It is usually used to support universal motors.

2) Sine wave Inverter

The output waveform of the voltage for this inverter is a sine wave and it gives us similar output like utility supplied electricity. The appliances which we’re using, these are designed for Sine wave. This is the appropriate output and gives guarantee that equipment will work properly. Sine wave inverter is expensive but it widely used in residential and commercial applications.

3) Modified sine wave Inverter

The output waveform of Modified sine wave inverter is neither exact sine wave nor the square wave. Modified sine wave inverter is complex than Square wave inverter but easier than Sine wave inverter. It is affordable and generally useful inverters. Using more basic type of technology than pure sine wave inverters, they produce power which is adequate for simple electronics. Modified sine wave inverter is used to provide power for your less sensitive appliances like telephone chargers, heaters and air conditioners etc.

How does the inverter work?

The basic circuits include an oscillator, control circuit, drive circuit for the power devices, switching devices, and a transformer.

The conversion of dc to alternating voltage is accomplished by converting energy stored in the dc source into an exchanging voltage. This is done by using switching devices which are turned on and off continuously, and afterward stepping up using the transformer. There are a few configurations which don’t use a transformer, these are not generally used.

The DC input voltage is turned on and off by the power devices, for example, MOSFETs or power transistors and fed to the primary side of the transformer. The changing voltage in the primary induces an alternating voltage at optional winding. The transformer works as an amplifier also where it expands the output voltage ratio determined by the turn’s ratio. The output voltage is increased from the standard 12 volts provided by the batteries to either 120-240 volts AC in most cases.

The three most commonly used Inverter o/p stages are, a push-pull with center tap transformer, push-pull half-bridge, or push-pull full bridge. The push pull with central tap is most popular because of its effortlessness and guaranteed results. Heavier transformer has been used for this and produces a lower efficiency.

How does an inverter can work with solar panels?

The Solar Inverter converts the solar panel generated direct current (DC) to alternating current (AC) in form of electricity. Different types of electrical and electronic components are connected each other within in the circuit to help in the conversion.

Sometimes we can use the direct current produced by Solar Panel for Solar lights, cell phone charger etc. But most of the time people used to convert the DC power to AC power for running the general applications live Refrigerators, TVs, etc. to reduce the general electricity bills.

Solar energy is changed to electrical energy with the help of photovoltaic cells (PV) solar energy is converted into electrical energy during the daytime. This electrical energy is stored in batteries & used for different purpose in future.

While converting the DC (Direct Current) output by a solar inverter of a photovoltaic solar panel into a utility frequency AC which will be used in commercial grid.

In the solar energy power system, the DC power from PV cells is stored in the battery.  After that, using the PWM inverter IC with MOSFET the energy stored in battery is converted into AC power supply of 50Hz.

Most commonly used Solar Inverter available in Australia

SolarEdge Single Phase Inverter: World record setting solar manufacturer with high efficiency and reliability. Perfect for all challenging weather conditions.  Maximum AC Power Output with Residual Current Detector.

KEHUA Inverter (SPI-B2 Series):  It’s most popular Single Phase String Inverter with Highly efficient inverter topology. It’s mobile app gives you real-time performance monitoring with intelligent cloud monitoring technology. It has built-In LCD Screen & IP65 aluminium alloy die-casted chassis with Reactive power control and DRM.

Growatt PV Inverter: If you looking for most efficient solar inverter? Growaat PV gives you the efficiency of 97.9% with Transformer less GT topology system. Also you will get wide range of input voltage, multi MPP controller & sound control.

Enphase IQ 7, IQ 7 and IQ 7X Microinverters:  This is the most popular and mostly available microinverters in Australia. It has high-powered smart grid-ready Micros with maximum level of system efficiency. It’s popular for faster installation with two-wire cabling system. It also optimized for high powered modules of 60-cell, 72-cell* and 96-cell*.

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