This Microwaves&RF article is reprinted here with permission.
Electric vehicles are getting larger and heavier, and that’s not just about SUVs and pickups. We’re starting to see commercial transport vehicles go electric: trucks, trams, buses, and so on. Those vehicles, as well as other industrial and transportation applications like auxiliary power systems, solar inverters, and solid-state transformers, need charging systems that rely on high-voltage switching power devices.
Today’s silicon insulated-gate bipolar transistors (IGBTs) have deficiencies in such applications. As an alternative to silicon IGBTs, Microchip Technology has expanded its silicon carbide (SiC) device portfolio with a family of high-efficiency, high-reliability, 1700-V SiC MOSFET die, discrete, and power modules.
Silicon IGBTs required designers to compromise performance and use complicated topologies due to restrictions on switching frequency due to the IGBTs’ inefficiency. In addition, the size and weight of power electronic systems are bloated by transformers, which can only be reduced in size by increasing switching frequency.
The new silicon carbide product family allows engineers to move beyond IGBTs, instead using two-level topologies with reduced part count, greater efficiency, and simpler control schemes. Without switching limitations, power-conversion units can be significantly reduced in size and weight, freeing up space for more charging stations, additional room for paying passengers and cargo, or extending the range and operating time of heavy vehicles, electric buses, and other battery-powered commercial vehicles – all at reduced overall system cost.
Features include gate oxide stability where Microchip observed no shift in threshold voltage even after an extended 100,000 pulses in repetitive unclamped inductive switching (R-UIS) tests. R-UIS tests also showed excellent avalanche ruggedness and parametric stability and with gate oxide stability, demonstrated reliable operation over the life of the system. The degradation-free body diode can eliminate the need to use an external Schottky diode with the silicon carbide MOSFET. A short-circuit withstand capability comparable to IGBTs survives harmful electrical transients. A flatter RDS(on) curve over junction temperature from 0° to 175°C enables the power system to operate at greater stability than other silicon carbide MOSFETs that exhibit more sensitivity to temperature.
Microchip streamlines the adoption of its technology with a family of AgileSwitch digital programmable gate drivers and wide range of discrete and power module packaging, available in standard and customizable formats. These gate drivers help speed silicon carbide development from benchtop to production.
To aid in system development, silicon carbide SPICE simulation models compatible with Microchip’s MPLAB Mindi analog simulator provide system developers with resources to simulate switching characteristics before committing to hardware design. The Intelligent Configuration Tool (ICT) enables designers to model efficient silicon carbide gate driver settings for AgileSwitch digital programmable gate drivers.
Microchip’s 1700V silicon carbide MOSFET die, discrete, and power modules are available now for order in a variety of package options.