Energy-efficient components and subsystems for high system reliability
Power semiconductors play a key role to produce energy from renewable sources. In wind turbines, power semiconductors are used to convert power and to couple the generator with the grid. They are also built into various auxiliary drives such as yaw drives, pitch drives, pumps and into protection circuits like crowbars.
Wind power converters control a number of vital functions and applications and therefore require power semiconductors of the highest quality standards. This applies in particular to offshore wind converters which operate in exceptionally harsh environments exposed to salt, humidity etc. Rapid growth is projected for the offshore segment.
Wind energy turbines must also be designed to deliver maximum levels of availability in order to contribute to grid stability. This applies not only to the converter, but also to the various auxiliary drives mounted in different positions. Grid stability therefore depends on power semiconductor assemblies offering dynamic capabilities, outstanding functionality and superior reliability.
Fixed-speed designs are suited to generators up to 400 kW. New designs are usually based on semiconductor solutions to fulfill grid code requirements. Nevertheless, Infineon delivers the full range of grid coupling components, with thyristors and other bipolar semiconductors available as modules, discs and stacks.
Doubly Fed Induction Generator (DFIG)
This speed-adjustable design is typically deployed in the power range between 400 kW and 2.500 kW. To control the full load, only up to one third of the energy needs to be converted over power semiconductors in both directions. Infineon’s IGBTs support optimum performance even at the limits of the operating range. High quality design, low voltage ride through (LVRT) capability and very low output frequencies meet high availability needs.
Permanent Magnet (PM) generators
Full converters for low-, medium- and high-speed generators provide maximum flexibility to meet LVRT and other grid stability requirements. High efficiency is mandatory and an active front-end inverter adapts variable power and frequency. This design reduces inductive component effort. Infineon’s IGBTs enable modular and scalable system designs.
Electrical Excited (EE) generators
An EE generator feeds the inverter via a bipolar rectifier, with the generator voltage controlled by excitation. The grid inverter is controlled by an IGBT as the effect of excitation. This design is an established solution already successfully deployed in modern systems.
Crowbars, choppers and active filters are important elements in wind turbine designs. Even though these components are not actively involved in feeding energy, they are needed to manage external impacts and fulfill grid stability requirements.
Several drives are needed for a wind turbine design to function safely and properly. Yaw drives, pitch drives and pumps can be controlled by small inverters. An energy storage solution must be connected to the DC link in pitch control drives to enable emergency shutdown.