Summary: IGBT is an an electronic switch. In solar inverters, this switch performs the key functions to convert direct current from the solar cells to an alternating current.

When you talk about inverters to many technical folks in the solar energy sector, they will almost inevitably say something about IGBT. What is an IGBT and what is its relevance in the solar power sector?

IGBT (Insulated-Gate Bipolar Transistor) is an efficient, fast switching device.

 IGBT Is a super-efficient component used in solar inverters to convert DC into AC

What is a switching device? A switching device, used as part of an electronic device, transforms electrical current from an AC line circuit to DC, or from DC to AC.

In a solar inverter, the IGBT performs the main role of converting the DC generated by the solar panels into AC required by the various electrical equipment.

Thus, the IGBT can be considered to be the core and most important component of a solar inverter.

Other than solar inverters, the IGBT is used in many applications where electronic circuits are required for power switching and modulation. It switches electric power in many modern appliances – examples include variable-frequency drives (or VFDs, systems that dynamically control motor speeds), electric cars, trains, variable speed refrigerators, air-conditioners and more.

Questions from the curious cat

How does an IGBT convert a direct into an alternating current?

The IGBT is similar to the power transistor, except that it is controlled by the voltage applied to its gate rather than the current flowing into its base, as in power transistors. The current flowing in the gate of an IGBT is extremely small because the impedance of the control gate is very high. This device is equivalent to the combination of a metal-oxide semiconductor field effect transistor (MOSFET) and a power transistor.

Since the current required to control an IGBT is very small, it can be switched much more quickly than a power transistor.

In inverters, an IGBT uses multiple switches in specific configuration to convert a DC voltage to a square wave ac voltage

Can an IGBT convert an alternating current to direct current too?

Yes, it can.

What are the core components of an IGBT?

An IGBT cell is constructed similarly to a n-channel vertical construction power MOSFET except the n+ drain is replaced with a p+ collector layer, thus forming a vertical PNP bipolar junction transistor.

This additional p+ region creates a cascade connection of a PNP bipolar junction transistor with the surface n-channel MOSFET.

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