Power Electronics Converter Topologies
Neutral-Point Clamped (NPC)
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), the Active Neutral-Point Clamped (in its 3-Level and Multi-level versions, the T-Type, the Multicell topologies such as the Flying Capacitor (FC), the Stacked Multi-cell Converter (SMC).
Example of a 3-level Neutral-Point Clamped (NPC)
Number of levels
- Typical: 3
- Max: 3
Initial patent US4270163A expired
Custom modules look for compensating:
- Poor distribution of losses by using different switches
- Large commutation loops by adding snubber diodes or capacitors
Typical application and trends
- Medium voltage drive up to 3.3kV
- UPS up to 690VAC
- Solar up to 900VDC
- Electric Vehicle
- Standard and custom modules available
- Unbalanced powerswitch losses (poor distribution)
- Large commutation loops