![]() Finally, while the market for all industrial motor drives is quite large, the market for any one particular voltage/current combination is relatively small, and some combinations of voltage/current just don’t make sense industrially. PWM frequency rarely exceeded 10 kHz, and was usually closer to 1 kHz, especially at 1,200 V and above). Also, industrial applications tend to be more concerned with reliability and efficiency than with minimizing size (and the noise from “singing” motors and transformers), so the diodes and switches inside the modules weren’t particularly fast (i.e. Furthermore, 3-phase motors also come in rather coarse power rating steps, so the current ratings for modules were equally coarse as well. Consequently, the available voltage ratings were in rather coarse steps of 600 V for 208-240 VAC mains applications, 1,200 V for 440-480 VAC, 1,700 V for 575-600 VAC, and so on. Prior to the emergence of OEM EVs, power semiconductor modules were designed specifically for industrial applications, with the vast majority being used in 3-phase motor drives supplied by the AC mains. These are obviously very different criteria, nor are they mutually exclusive, but suffice it to say that if you need to switch >100 A RMS at >100 kHz, then you’re looking at a design challenge worthy of a PhD dissertation. Despite the radical differences in their physical (and, often, electrical) aspects, there’s no clear distinction for when to choose a plastic package component or a module using a rather broad brush to delineate between the two, modules are preferred if more than 50-100 A RMS must be handled, whereas plastic packages are preferred if switching frequency must be considerably above the ultrasonic range (e.g. ![]() ![]() Modules also tend to have screw terminals for the high-power connections and pin or spring terminals for the low-power connections, making integration into a bused structure (and replacement of a damaged module) much easier. a half-bridge plus a temperature sensor), all mounted on an electrically-isolated heat spreader. The power semiconductor components most likely to be used in EVs come in two different form factors: (1) plastic types such as the TO-220 and TO-247 packages, which feature wire leads and a (usually non-isolated) heatsink tab, and which typically contain a single diode or switch (with or without anti-parallel diode) (2) modules, which typically contain several components pre-wired in commonly used configurations (e.g.
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