Power Electronics Converter Topologies
3-Level T-type

Multilevel converters have emerged in recent years as a very important alternative in the area of high-power medium-voltage energy control. The need for an increase in the power level of industrial applications is especially important in high power applications such as high power AC motor drives, active power filters, and renewable energies.

The term multilevel refers to the three-level topologies and above. The increase in the number of levels in the converter leads to harmonic distortion. Yet, as the number of levels increases so does the control complexity.

The most common multilevel topologies include the Neutral Point Clamped (NPC) converter (in its 3-Level version) and the Active Neutral Clamped (ANPC) (in its 3-Level and Multi-Level versions), the T-Type, the Multicell topologies such as the Flying Capacitor (FC), the Stacked Multicell Converter (SMC).

Electrical schema

power converter topologies 3-level T-type

Example of a 3-level T-type

Conversion stage

  • DC/DC mono and bi-directional

  • DC/AC mono and bi-directional

Number of levels

  • Typical: 3
  • Max: 3

Intellectual Property

Initial patent expired

Notes

Outer switches block the full voltage but switch only half the voltage. Thus, they can be composed of a direct series connection of switches with a proper command to handle a voltage level as high as a NPC.

Typical application and trends

  • Medium voltage drive up to 3.3kVAC
  • UPS up to 690VAC
  • Solar up to 900VDC
  • Electric Vehicle

Advantages

  • Efficient use of powerswitches

Drawbacks

  • Only 3-Levels

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