Liebherr as system solution provider for control and drive systems at the Electric & Hybrid Marine World Expo 2016 in Amsterdam

Once again, the components division of the Liebherr Group will be demonstrating its competences in the field of control technology and drive systems in Amsterdam, from 21 to 23 June. Modern control and regulation technology combined with reliable power electronics makes for high efficiency and cost-effectiveness, thereby generating added value for all users.

For decades, Liebherr has provided components and system solutions for on- and offshore applications such as ship, offshore and container cranes, and specialized equipment. Our product portfolio for the maritime industry comprises, among others, control cabinets and switchgear, frequency converter systems, energy storage units, electric motors and AC generators. As early as the 1950s, Liebherr was already working on the electrification of its appliances, and had itself begun to develop and produce control and drive technology along with electric motors and generators. At first, these products and systems were used exclusively in Liebherr's own machines, such as tower cranes, maritime cranes (port equipment) and off-highway vehicles. In the '80s, PLC controls and - for the first time - proprietary power electronics modules were developed for the operation of ship-to-shore cranes. Since then, this technology has been further refined and expanded to incorporate frequency converter systems and energy storage systems (accumulators) based on double-layer capacitors. The brand name "Liduro", under which Liebherr power electronics are marketed, stands for durable and robust components, suited to extreme conditions and characterized by the utmost reliability.

Diesel-electric drive systems from Liebherr

More material handled in less time, while reducing energy consumption at the same time: these are the characteristics of a modern and future-oriented drive system. The Liebherr solution exhibited at the Electric & Hybrid represents a complete one-stop energy conversion system.

A key component of an efficient system is the intelligent control and regulation of the entire drive train. Low-loss frequency converter systems, speed regulation of the combustion engine for diesel-electric drives, and the supplemental use of accumulators offer further possibilities for increased efficiency in application. Frequency converters are essentially extremely efficient. However, according to application and load this efficiency can still be improved further through adaptation of the regulation strategy during operation.

A further possibility for the reduction of operating costs is the additional use of a suitable energy storage unit. In April 2016, Liebherr presented for the first time the proprietary energy storage system it had developed for electric drive systems and plants. This is based on double-layer capacitors and can be deployed as a modular "connect & use" system for effective energy use. The fully-integrated complete system includes all necessary individual systems and components, considerably simplifying integration in new and existing mobile and stationary applications. Easy system integration, installation and operation make for considerable savings in terms of time and material costs.

The integration of an energy storage unit also makes sense when the electric motors supplied by the on board power supply provide no energy feedback. During periods of reduced use, the onboard generators can recharge the energy storage unit. This energy can then also be used to minimize the starting currents for load impact. This considerably reduces the load on the generators and enables optimized configuration of the overall system, since this makes it easier to comply with the requirements relating to permissible voltage dips, as specified by the classification company.

The combustion engine speed is regulated directly on the basis of the actually required power rating, meaning that engine losses are kept to a minimum. The challenge here is to adapt the engine speed precisely enough, so that the exact power required is available when needed, without the engine being overloaded.

Liebherr places great value on offering the appropriate solution for the drive requirements stipulated by the client. For maximum productivity and efficiency, the focus lies on precisely calibrated complete systems. All essential components of such systems are developed and produced in Liebherr's own facilities. This allows Liebherr to react with greater flexibility to customer needs, and to offer process security and hence constantly high product quality.

The development of a corresponding maintenance and service strategy constitutes a further step in the design process.