DC/DC converter for fuel cell vehicle
Development and production of a customized full functional 21-kW DC/DC converter in only 8 months.
Our customer needed a DC/DC converter for his former prototype to charge a battery with a fuel cell. First, he scanned the current market – unfortunately the required component did not yet exist and therefore needed to be developed. Essential specifications: Functionality, robustness, time-to-market. Less important: Size, weight, suitability for series production.
Based on standard components, Michael Rübig developed an initial solution. The limited IGBT modules available on the market were purchased immediately to prevent delivery delays. A first circuit design was simulated using SPICE circuit simulation technology.
A housing for the converter
In order to install it in a car, the DC/DC converter was accommodated in a die-cast aluminium housing. Kaiser Ingenieurbüro, our partner in this development, designed a matching base plate with a water cooling system. Based on our standard microcontroller platform, the circuit diagram was generated. Two CPLDs were designed to support the controller in time-critical operations. Herbert Spinner implemented our customer’s control concept. An emulator for power electronics was developed to enable the software engineer to immediately begin creating the software while the 21-kW version was being worked on.
Due to the limited amount of AC electrical power available at our premises, the initial commissioning with up to 12 kW proved unspectacular. During tests at the customer’s test facilities, some limits began to appear, requiring a derating at a higher temperature. All other requirements were satisfied up to 21 kW.
The customer was provided with two identical converters. Since neither of the converters failed during the development phase, the IGBTs, which had been purchased as reserves, had never been needed.