Max Beuermann

Converter Topologies and Power Semiconductors for Industrial Medium Voltage Converters

Today there are numerous different converter topologies and power semiconductor devices used in medium- voltage drive systems. This paper provides a general overview of the common converter topologies available on the market and their corresponding major characteristics. The different topologies are compared and evaluated with respect to their semiconductor effort. Due to the available power semiconductor devices with maximum blocking voltages of 6.5 kV, the drive market with power ratings up to 25 MW is dominated by voltage source inverters in IGBT as well as in IGCT technology. For higher power demands and special applications, thyristor converters are still frequently used.

Medium-Voltage Drives

An overview of the common converter topologies and power semiconductor devices is given. This article provides a general overview of the common converter topologies available on the market and their corresponding major characteristics. The different topologies are compared and evaluated with respect to the number of semiconductors and the complexity.

A new modular multilevel converter for medium voltage high power oil & gas motor drive applications

This paper presents the first commercially available water-cooled MV motor drive based on the Modular Multilevel Topology (M2C). The motor drive specific features and HW are described. Measurement results from a 12 MW back-to-back test is included, e.g. operation at low motor frequencies down to zero speed at high torque.

Complete performance test of MV drive with modular multilevel topology for high power oil & gas applications

More than ever Oil & Gas companies are looking for ways to increase their productivity and energy efficiency. To realize these goals electrification of the drive trains is essential. These solutions make use of variable speed drives to control speed and torque of the gas compressors and pumps which leads to a higher degree of process optimization. For loads with power requirements higher than 1 MW, Medium Voltage (MV) drives become the most utilized drive solution. Depending on the output power, several different topologies of MV drives are available on the market. The modular multilevel converter (M2C) topology is the latest topology to enter the high power medium voltage drive market. To ensure that the performance of the whole drive system meets the performance data as specified by the customer, a system tests with a 12 MW motor in a back to back arrangement has been executed. The measurements of the output performance, the start-up behavior and more will be presented.

High-inductive short-circuit Type IV in multi-level converter protection schemes

To build a redundant medium-voltage converter, the semiconductors must be able to turn OFF different short circuits. The most challenging one is a hard turn OFF of a diode which is called short-circuit type IV. Without any protection measures this short circuit destroys the high-voltage diode. Therefore, a novel three-level converter with an increased short-circuit inductance is used. In this paper several short-circuit measurements on a 6.5 kV diode are presented which explain the effect of the protection measures. Moreover, the limits of the protection scheme are presented.