Modular multilevel converter for hybrid grid

Design of highly reliable modular multilevel converters

Owing to their higher efficiency, improved power quality, inherent fault-tolerance, and enhanced density, multi-level modular converters expand to MV- and HV- power conversion stations, replacing legacy 2-level inverters.

The challenge

Today power electronic semiconductors and capacitors thermally limit the lifetime and overload capability of power electronic converters. Due to that, the temperature peaks of the semiconductors can be reduced using an appropriate control, which extends the overcurrent operating range of the modular multi-level converter (MMC) in the head-end station. However, the junction temperature of the semiconductors must be known to achieve this performance. That is why we offer measurement technologies to determine the junction temperature indirectly, avoiding the challenge of measuring it directly.

Our solution

We offer a measurement technology to determine the junction temperature of the semiconductors indirectly via thermal-electrical sensitivity parameters (TSEP). By connecting the measurement technology to the gate drivers of the MMC cells, the junction temperature can be output as a function of the collector-emitter voltage, for example, and used for overcurrent operation or self-protection of the power converter.

Our portfolio

  • Medium-voltage MMC
  • Junction temperature estimation technology

Our offer

  •  High reliable AC/DC conversion
  • Converter overload management
  • Indirect semiconductor temperature monitoring
  • DC filter reduction

Applications fields

  • HVDC and MVDC
  • Fast charging stations
  • Shipboard system

Your benefits at a glance

The MMC is a key technology for medium-voltage AC/DC applications. Since this kind of topology requires a high number of power electronic devices, it is important to provide a highly reliable converter ensuring uninterrupted operation and reduced maintenance time. Then, we provide an MMC with overload capability using an independent TSEP on other variables outside of temperature. Such solution indirectly monitors the temperature of the semiconductor, which allows the management of overload and extends a lifetime of converter.

Our use case


AC2DC - Converting AC connections to DC connections with higher power transmission