Power designers have their hands full. Not only do they need to keep up with constant increases in power levels, they also need to find creative ways to continuously improve the efficiency and power density of power supplies. At high voltages, these challenges become more prominent.
Delivering efficient power conversion in high-voltage systems requires an in-depth knowledge of high-voltage components, electrical and magnetic circuit modeling techniques, an understanding of insulation requirements for functional or safety isolation, expertise in electromagnetic compatibility, power-converter control techniques and more.
Simplifying high-voltage power design is a challenging task, but not an impossible one.
Sheng-yang Yu
System Manager
Power Design Services
This white paper examines the challenges of efficient high-voltage power conversion and provides examples of component, topology and system-level innovations that help simplify power-supply designs in automotive and industrial applications.
| 1 Optimizing wide-bandgap FET performance with component innovations | Wide band-gap field-effect transistors (FETs) offer a higher-efficiency
alternative to metal-oxide semiconductor field-effect transistors (MOSFETs)
but require specialized companion devices such as isolated gate drivers and
digital controllers for optimum performance. |
| 2 Maximizing power density with topology innovations | Selecting the right topology can greatly influence the power density and
efficiency of a high-voltage power design. |
| 3 Achieving extreme efficiency targets with system-level innovation | System architecture innovations and control system innovations can help
designers achieve higher efficiency and power density. |
As the worldwide electrification trend continues to gain momentum, efficient energy transfer at higher power levels becomes an important consideration in today’s power electronic systems. Resistive loss (I2R) is the central factor limiting how much power a power supply can deliver. To improve system efficiency, increasing the voltages used to transmit and deliver power reduces the required current for the same power level and helps minimize losses through heat.
A few examples of high-voltage systems widely applied in today’s power networks include residential AC distribution power systems, telecommunication and server power systems, DC microgrids in renewable energy systems, energy storage systems, and electric vehicle (EV) onboard and offboard chargers. As an example, EV batteries are currently 400 V but increasingly trending toward 800 V in order to enable more instantaneous power transfer to the traction inverter for better acceleration performance.
Although operating under a higher voltage brings system efficiency benefits for power conversion, proper galvanic isolation and insulation are essential to allow a safe human interface. Moreover, a closed-loop system generally requires signal communication across the isolation boundaries. Add to this topology selection, magnetic circuit design, electromagnetic interference considerations, operating modes, thermal management, and layout and control optimizations, and you begin to understand some of the significant design challenges when working with high-voltage systems. Overall, innovations from three key areas – component innovations, topology innovations and system-level innovations – will increase high-voltage power-conversion system's efficiency and density, while simplifying designs.