Traction Applications

The rail market is rapidly expanding year on year due to the increasing demand for more efficient, cost effective and faster means of transport.

IGBT

Dynex offers a broad product portfolio of IGBT modules ranging from Trench Gate to mature and extremely robust DMOS+ and SPT products. Refer to AN5700 for naming nomenclature and product configuration explanations.

Traction

Dynex offer a range of specifically designed devices for the traction market. The devices provide an efficient source of energy whilst working to high reliability for long periods of time.

Most importantly among Dynex’s IGBTs is the ability to choose a low Esw,(switching loss optimised) low Vce (conduction loss) or Balanced Losses optimised IGBT.

Traction

Refer to AN6156 for power loss estimation of Dynex IGBTs and Dynex Design Tool for web hosted simulator; PLECs models are available for Dynex IGBTs.

The Dynex range of 1.2kV to 6.5kV IGBT modules are primarily suitable for use in traction applications that require thermal cycling capability. These modules are available in single, half bridge and chopper configurations and are designed in various packages types.

Thermal Management

IGBTs are designed to handle high levels of heat generated during the power conversion process. Their improved thermal stability and ability to operate in high-temperature environments make them suitable for demanding traction applications, where continuous operation is required.

The ability to implement regenerative braking using IGBTs is a significant advantage in traction applications. It saves energy and reduces the wear on mechanical braking systems leading to lower maintenance costs and extended equipment lifespan.

The durability and reliability of IGBTs result in lower maintenance costs and longer intervals between service checks. This is particularly important in rail systems, where downtime can cause significant disruptions.

Traction

Figure 1 IGBT Traction Application

Bipolar

The Bipolar range of Gate Turn Off Thyristors ( GTO’s ) 1300V to 4500V are primarily designed for use in railway traction and light rail propulsion drives. The devices are highly reliable, reducing the need for maintenance and replacement throughout their years of service. They have been designed to enable DC turn on and off in a controlled manner.

Traction

Figure 3 Bipolar Traction Application

Dynex DSF Range of Fast Recovery Diodes are the ideal combination to be paired with Dynex GTOs for inverter applications. The table below illustrates which FRDs can be utilised with Dynex GTOs. For traction rectification applications Dynex offers our DCR range of Phase Control Thyristors, and DRD range of Rectifier Diodes.

Dynex offers several Application Notes for Bipolar Products.

Traction

Figure 4 GTO and FRD Pairing

In addition to our standard and customised semiconductor product offerings, Dynex Power Assemblies team can provide traction converter upgrade and overhaul. Dynex can offer an assessment of the likely health of semiconductors in application, as well as providing a feasibility report on the current availability of equivalent parts available for replacement or spare stock.

Dynex offer the following capabilities to support this; re-traction of propulsion systems, converter mid-life upgrade and overhaul, reliability improvements and replacement Semiconductor devices. The mid-life upgrades offer a number of benefits including; improved reliability and maintainability resulting in reduced life cycle cost, availability through lower downtime and higher reliability and obsolescence management offering full collaborative agreement with Dynex insures long-term UK support for spares and maintenance.

Specific traction applications include; trams, light rail, commuter rail, high speed-rail, transit rail, intercity rail and freight rail.

Traction Application Frequently Asked Questions

What is a Gate Turn-Off Thyristors role in regenerative braking systems for trains?

GTO's are essential for efficiently controlling power flow during braking, enabling the conversion of kinetic energy back into electrical energy that can be fed back into the power grid, or reused thereby reducing overall energy consumption.

GTOs act as high-power switches that control the current flow between the traction motors and the electrical system. By turning on and off at high speeds, they allow precise control of the braking energy conversion process.

GTOs can handle high voltages and currents, making them ideal for the demanding conditions of train operation. Their ability to turn off rapidly allows for better control of the braking process, improving overall system efficiency.

GTOs are robust and can endure the repetitive and harsh conditions typical in railway systems, contributing to the reliability of the regenerative braking system.

Modern regenerative braking systems often use a combination of GTOs and other semiconductor devices like IGBT modules to optimize performance. GTOs are preferred in high-power applications due to their capability to handle larger currents.

Traction Applications:

For freight trains carrying heavy loads, GTOs provide the necessary power handling capabilities to manage the large amounts of energy involved in braking.

GTOs are commonly used in high-speed trains where precise and efficient braking is crucial.

How does a gate turn-off thyristor (GTO) work?

A gate turn-off thyristor (GTO) is a high-power semiconductor device. It works by acting as a switch in high voltage circuits. Like a thyristor (SCR Silicon-Controlled Rectifier) it has 3 terminals; anode, cathode and a gate terminal. Both a GTO and SCR have a controlled turn on function via the application of a positive pulse to the gate terminal, but the GTO also has controlled turn-off function by the application of a negative pulse to the gate terminal. An SCR only turns off when the forward current drops below the threshold holding current The turn-off time is typically more than 10 times faster than for an SCR (silicon-controlled rectifier) thyristor.