Difference between Two-level and Multilevel Inverter

Two-level inverters and multilevel inverters are the types of inverters based on the levels in the output voltage waveform. Multilevel inverters offer superior performance compared to two-level inverters with the same power ratings. The basic difference between two-level and multilevel inverters is that a two-level inverter generates two levels in the output voltage waveform whereas a multilevel inverter generates more than two levels in the output voltage waveform.

Difference between Two-level and Multilevel Inverter

In this section, we will see the differences between two-level and multilevel inverters in detail.

Due to the semiconductor’s blockage voltage limitation, conventional two-level inverters cannot operate at medium voltages. On the other hand, multilevel inverters play an important role in medium-voltage and high-power applications.

Multilevel inverters offer advantages over two-level inverters in terms of reducing the harmonic content of line-to-line voltages that are fed to the load.

The structure of a 2-level inverter is complicated whereas a multilevel inverter has a modular structure.

The stress on power electronic switching devices is higher in two-level inverters as compared to multilevel inverters.

Two-level inverter finds use in low-voltage applications whereas multilevel inverters are used in medium-voltage and high-power applications.

A two-level inverter provides low power quality as compared to multilevel inverters.

The harmonic content of output in the case of a two-level inverter is higher as compared to a multilevel inverter.

Electromagnetic interference (EMI) immunity/susceptibility is lower in the case of a two-level inverter as compared to a multilevel inverter.

Electromagnetic interference (EMI) generation is higher in the case of a two-level inverter as compared to a multilevel inverter.

The production of common-mode voltage is higher in the case of a two-level inverter as compared to a multilevel inverter.

A two-level inverter doesn’t have the ability of transformer-less operation whereas a multilevel inverter has the ability of transformer-less operation.

A two-level inverter has lower efficiency as compared to a multilevel inverter.

A two-level inverter has higher switching losses as compared to a multilevel inverter.

A two-level inverter fails to operate at fundamental switching frequency whereas a multilevel inverter can operate at fundamental as well as high switching frequencies.

The input current distortions are higher in the case of a two-level inverter as compared to a multilevel inverter.

The fault-tolerant operation is impossible in the case of a two-level inverter whereas fault-tolerant operation is possible in the case of a multilevel inverter.

The rate of change of voltage (dv/dt) is higher in the case of a two-level inverter as compared to a multilevel inverter.

The production of multiple voltage levels is impossible in the case of a two-level inverter whereas it is possible to produce multiple voltage levels in the case of a multilevel inverter.

The above-mentioned differences are summarized in the following table.

Two-level Inverter	Multilevel Inverter
It generates two levels in the output voltage waveform.	It generates more than two levels in the output voltage waveform.
It has a complicated structure.	It has a modular structure.
It is used in low-voltage applications	It is used in medium-voltage and high-power applications.
There is more voltage stress on power electronic switching devices.	There is lesser voltage stress on power electronic switching devices.
It provides low power quality at the output.	It provides high power quality at the output.
The harmonic content of the output is higher.	The harmonic content of the output is lower.
It has lower electromagnetic interference (EMI) immunity/susceptibility.	It has higher electromagnetic interference (EMI) immunity/susceptibility.
Electromagnetic interference (EMI) generation is higher.	Electromagnetic interference (EMI) generation is lower.
It produces higher common-mode voltage.	It produces lower common-mode voltage.
It doesn’t have the ability of transformer-less operation.	It has the ability of transformer-less operation.
It has low efficiency.	It has high efficiency.
It has higher switching losses.	It has lower switching losses.
It cannot operate at a fundamental switching frequency.	It can operate at fundamental as well as high switching frequencies.
The input current distortions are higher.	The input current distortions are lower.
The fault-tolerant operation is impossible.	The fault-tolerant operation is possible.
The rate of change of voltage (dv/dt) is higher.	The rate of change of voltage (dv/dt) is lower.
The production of multiple voltage levels is impossible.	The production of multiple voltage levels is possible.

There are many advantages and disadvantages of multilevel inverters in comparison to two-level inverters. I hope this article helps you in getting an understanding of two-level and multilevel inverters.