There are different strategies on the market for integrating the electrical drivetrain in the truck. One very promising concept is the integration of the electric motor and inverter directly on the electrified axle. This approach offers a high degree of integration, enabling better scalability, as each electrified axle can be operated as an independent drivetrain. It also leads to a reduction of rotating parts and mechanical interfaces, as no mechanical transmission is required from a single electric motor and inverter to each axle. One challenge with this approach is that higher vibration loads are transferred from the road to the sensitive electronic devices. These tough requirements must be met by using a robust mechanical design and connection technology of the power module. In addition, reducing the components’ volume and mass is a common way to enable high power density on the one hand, and to minimize the resulting mechanical forces, due to, e.g., vibration loads, on the other hand. Typically, the highest power densities are achieved by utilizing fast switching devices like SiC MOSFETs. In this case, it is mandatory to provide a power semiconductor module design with a very low stray inductance. Thus, a low inductive design is required. The stray inductance of a power module is directly dependent on the time rate of change of the electric current and the electric voltage. That is why it is important for fast switching devices to reduce inductance via the design to prevent critical overvoltage, and to enable high switching speeds and minimize switching losses. The stray inductance of the system is mainly influenced by the sum of all internal and external inductive elements in the commutation path.
For the efficient use of electrically powered trucks, it is necessary to adapt the charging cycles to the legally prescribed rest periods of the driver for heavy goods vehicles. This requires charging power above 1 MW. To provide this, operational voltages of Vbat 1250 V with its approx. 1500 V end of charge voltage are envisaged here. The main reason for increasing the battery voltage with increasing power demand is to reduce the conductor cross-sections, and thus to reduce mass. To meet the requirement for higher board voltages and to enable applications for altitudes of up to 5000 meter above sea level (m.a.s.l.), the Hybrid PACK ™ HD provides a future-oriented insulation concept. The clearance and creepage distances are designed to provide a compatibility of voltages up to 1500 V.