In order to transport containers in ports or to other transshipment points, suitable vehicles are needed that can both stack and transport containers. The straddle carrier is perfectly suited for such cases. Previously, such systems were fitted with diesel drives and hydraulic units, today, however, diesel-electric systems are the best technology available. Electric drive technology has the advantage over hydraulic systems of having increased energy efficiency and better regulation. As a result, it complies with the demands of the port operators of always utilizing environmentally friendly systems with significantly reduced CO2 emissions and reduced fuel consumption. Energy is also generated when the hoisting unit is lowered and when the vehicle is braked. With the aid of an energy storage system, this energy can be efficiently used again either for vehicle acceleration or for lifting purposes.
The diesel engine drives the electric generators that supply the electrical energy for all inverters. The chassis drives are torque-controlled and work with overriding trip units that intervene when the maximum revs are exceeded and when a drive is recorded as having too high a speed (differential speed of a drive is too high). In addition to this, they also carry out controls on the brakes and monitor the motor temperature. Anti-skid and anti-slip protection, as well as traction control, are functions integrated in the inverter. The hoisting unit is speed controlled and operates in 1:2 field weakening mode and with very short acceleration times. The inverter calculates the load, where as the maximum final rotation speed for the lowering mode is set. All functions are implemented directly using the inverter’s free configuration, so that the higher ranking PLC control is relieved of the tasks. As a result, the customer does not require any special knowledge on drives. An on-board converter provides a high quality 3 AC 400V; AC230V + N power supply. The optional DC-DC controller regulates the energy storage system.
Power electronics from REFU
- 4 REFUPCS 075 (chassis inverter for 4-wheel drive)
- 1 REFUPCS 160 (hoisting inverter)
- 1 REFUPCS 045 (on-board inverter)
REFUPCS 085 DC-DC controller
CANbus (Canopen) on all REFU components for communicating with the vehicle control system
Supplemented by customer with
- Motor (synchronous generator, asynchronous motor, sensor-equipped operation)
- Resolver, 6-pole, incremental encoder HTL/1024 pulses
- 6 x double layer capacitor 63F/125V