Power conversion is an essential function in almost every design, from low-power IoT sensors to high-power solar inverters. Trends such as using renewable energy sources and the growth of electric vehicle adoption demand efficient and reliable energy conversion. This article highlights some of these trends, explores the electronics engineering challenges, and explains how wide bandgap silicon carbide (SiC) technology has quickly gained adoption. Thanks to its efficiency and size advantages over other semiconductor process technologies, SiC is ideal for use in high-power applications.
We focus on one application – a fast DC EV charger- and discuss a typical charger’s engineering challenges and high-level architecture. The design considerations of a discrete v. modular approach is discussed briefly, followed by a showcase of the onsemi F1 half-bridge module.
The Challenges of High-Power Energy Conversion
Power conversion is a broad topic. Power conversion and management is as essential for a battery-powered edge node IoT sensor as it is for a large commercial solar power converter. The difference between them is the level of power involved. The sensor may be only drawing a few milliwatts during operation compared to potentially thousands of watts for the solar power unit. Power conversion is vital in converting from one voltage level to another. For example, the IoT sensor’s microcontroller typically sets the voltage requirement, with 3.3 V or 5 V being popular. However, the nominal voltages of battery chemistry often used for this application provide 3.7 V. The same applies to higher power applications such as solar charge converters, uninterruptable power supplies, and electric vehicle chargers. Conversion from one voltage to another is, therefore, required. Despite the vast power differences between these application examples, conversion efficiency is crucial. In high-power conversion applications, an inefficient power conversion results in energy losses that manifest as heat. Too much waste heat requires dissipation to keep the electronic circuitry cool and to work reliably. Dissipating the heat and drawing it away from the power conversion semiconductors is a thermal challenge.