Requirements of hybrid and electric buses - a huge challenge for power electronics

The ongoing development of drives for city buses is marked by an increasing hybridization and electrification. A high operation time and the utilization of new drive concepts using permanent-magnet synchronous machines (PMSM) require very durable power electronic and hence power semiconductor technology. First of all the article will initially explain current and future city bus drive concepts and then look at the resultant requirements on power electronics. Starting with state-of-the-art drives it will be shown that future drive concepts using PMSM will result in new requirements for power electronics and especially on the load-cycling capability of IGBT. Strategies to fulfill these requirements will be discussed in the second part. The last chapter provides an overview of promising new packaging technologies for power semiconductors. The potential thermal cycling capability of these new technologies will be estimated. Finally the potential of SiC for the lifetime of electric drives will be briefly evaluated.