The hybrid drive, or the combination of a combustion engine and an electric drive offers environment-friendly mobility and is considered the immediate future of vehicle technology.
Off-highway applications as well as agricultural and construction machinery, forklifts, utility vehicles and public transport will benefit from full electric mobility. These applications are perfectly suited to the benefits of diesel electric drives.
With STW’s involvement in several hybrid electric projects, some components and modules of their powerMELA hybrid technologies have also found their way into working passenger and commercial vehicle prototypes such as:
- Fuel cell hybrid electric vehicle
- Hybrid electric truck for city distribution
- Plug-in hybrid electric vehicle for light commercial applications
- Hybrid electric driven snow snowplough
- Hybrid electric fire and rescue truck
- Hybrid electric tractor for agriculture
Mobile machines and off-highway vehicles typically experience frequent load cycles. The lifting and sinking of loads and machine parts as well as the accelerating and braking of the entire vehicle or heavy machine components converts large amounts of energy.
While this energy is provided by the combustion of diesel and then dissipated as waste heat in conventional machines, in a hybrid system the energy can be recovered and stored in a battery for use in a following load cycle, leading to significant savings in fuel and emissions.
In addition to energy and emission savings, electric drive systems open new possibilities through good controllability.
- Partial automation reduces the workload on personnel and increases productivity
- Diesel motor operates at the optimal working point
- Smaller diesel motors
- Additional drive energy from the battery
- Substantial increases in overall efficiency
Sensor-Technik Wiedemann GmbH is a competent system partner for mobile electric drives, power inverters, batteries and battery management systems, electric power management as well as safety, cabling and connection technologies.
STW places a high value on safe, reliable systems with a long service life. Key features include:
- All components feature redundant protection of the high voltages
- All power components are actively cooled ensuring long service life of batteries and inverters
- All components feature high voltage connectors that simplify the installation and maintenance
- Patented and user-friendly electric power take-off is available for the connection of accessory equipment and implements
Central power management unit communicates over the CAN bus with all producers and consumers in the system, evaluates supply and demand based on capacity and permanently optimises the distribution of available electrical energy.
CAN Automotion offers proven modules customised for different machine applications, components and complete systems for manufacturers seeking hybrid electric solutions from STW's powerMELA range.
STW's powerMELA Hybrid Electric System Overview
All STW drives are designed as 4 quadrant drives and operate as motors and generators.
The classic design is connected to the power train over a distributor gear. The crank shaft generators are designed to be directly connected to the crank shaft housing.
STW employs safe, long life and robust Lithium Ion batteries, and is a manufacturer of these battery management systems (BMS).
The BMS monitors the current voltage, cell voltages, temperature and insulation integrity. The redundant safety architecture ensures maximum safety when operating batteries.
STW has developed in association with partners, a portfolio of high voltage batteries suitable for vehicles with up to 800 volts and 150 kW capability.
With the bi-directional converter as the link between the HV traction net and the 12/24 volt net, a starter/generator can be incorporated. This replaces the existing starter and alternator/generator. A start-stop functionality is easily realised.
Plug-in hybrids allow recharging of the battery from a mains power socket, making pure electric drive possible. A charger built into the vehicle transforms the mains voltage to the high voltage required for the battery.
All drives are designed with direct oil cooling to enable effective operation in difficult conditions. A combined conduit with cooling fluid and HV traction net power minimises the cabling effort.
The BT and C series drives operate at up to 6000 RPM and for the final drive operate over a gearbox. The C series has an integrated inverter for direct connection to the HV traction net.
The high voltage coupling enables the safe connection and disconnection of implements and accessories to and from the HV traction net.
STW also offers drives for lower power ranges for driving ancillary loads such as fans, pumps and compressors.
230V/ 400V Inverter
The bi-directional power inverter supplies a standard 230V or 400V-AC power socket for external use. Saws, pumps and welding machines can all be powered.
All components of the powerMELA hybrid electric system are protected with isolation monitoring. Drive components include relay isolation.
The high protection class enables continued operation in the case of an isolation failure, improving machine availability.
The power management of the powerMELA hybrid electric system manages the operation of all components on the HV traction net, and forms the interface to the vehicle control system.