Output power

As mentioned in our previous article, the specific number of silicon carbide chips placed in a SiC motor control unit (MCU) greatly impacts the achieved level of efficiency and peak output power. The simulation results of our in-house developed ScanTool show the maximum output power of a SiC MOSFET power module compared to a commonly used Si IGBT power module under the same working conditions and packaging dimensions:

12.4% output power increase — if 6 chips are used in parallel
31.0% output power increase — if 8 chips are used in parallel

In particular, our testing revealed that the MCU switching frequency and by that also the fundamental frequency of the motor can both be greatly increased without causing a significant output power derating. Thus, silicon carbide brings indisputable advantages in particular for high-speed motor applications.

Specific advantages

With the same battery capacity, the mileage of a car equipped with a SiC MCU can be increased by 4.4%. This savings in terms of energy consumption is a great advantage, resulting in long-term financial benefit compared to using an IGBT based MCU.

Summary

Applying silicon carbide to our in-house developed motor control unit product platform, we come to the following observations:

Greater efficiency leads to savings in electrical energy (OPEX) and battery costs (CAPEX).
The right amount of SiC chips being placed is a trade-off between energy savings and peak power performance
The accurate analytical modeling and the in-house developed toolchains are essential to achieve a best-in-class SiC power module design
Passenger vehicles of class A can achieve an endurance mileage increase of more than 4.4%

For reference and more information, please read the full-length research paper published on the ROHM Semiconductor website:

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SiC at its best! Our conclusion.

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SiC at its best! Performance & efficiency tested.