Silicon Carbide in Hybrid Vehicles – Development of an Efficient High-Temperature Converter with Compact Boost Converter (SiC Boost - VSI, FVA No. 637 II)

The overall aim of this project is the construction and functional testing of an efficient and compact high-temperature converter with boost converter and novel silicon carbide power semiconductor switches for hybrid vehicles. The dimensioning methods and rules  developed in preliminary work shall be validated for the chip surface and the passive components of the converter system, in order to  identify the potential of SiC semiconductor technology for automotive applications by experiments. In addition,  the assumptions described in the following shall be verified and confirmed. 

• With the use of  SiC semiconductor chips, a more efficient power electronics can be set up than with Si-IGBTs, and this despite a reduced chip surface and increased switching frequencies.

• Disadvantages due to fast switching can be reduced by the setup and constructive measures for the requested power class, so  that high switching frequencies are permitted (DC link connection, load connection, possibly modular design).

• The energy storage demand in passive components is reduced by an increased switching frequency, so that volume can be reduced without exceeding the thermal limit of the components (inductor, DC link capacitor).

• Due to an optimised system management, load on the system components can be reduced or shifted, thus being able to increase system utilization and power density  (DC/DC  converter, inverter, DC link capacitor).

• The DC/DC converter enables mismatch compensation between the requested motor voltage level (number of turns per motor) and battery voltage level (SOC-dependent) during operation.

One major contribution is also to investigate the predictability of additional cost (gate drive) as well as possible savings (system components, volume) by use of SiC semiconductors. The final goal is a direct comparison of features of existing systems and systems presently in use.