FiddlerJohn
Well-known member
Metal Oxide Field Effect Transistor (MOSFET) vs. the Insulated Gate Bipolar Transistor (IGBT)
For the technically minded, here is a nice simple article in switching device tradeoffs.
http://chargedevs.com/features/a-closer-look-at-the-semiconductor-switch/
Executive summary:
MOSFETs are preferred in low voltage or high switching frequency applications, but the lack of minority carriers means conduction losses increase rapidly with blocking voltage (a square function). The MOSFET is better for most “hard-switched” DC-DC converter and chargers.
IGBTs are preferred at higher voltage/higher power applications with lower switching frequency. The IGBT is better for most motor controllers.
The i-MiEV:
I'm sure the MiEV uses IGBTs for the motor controller, but I'm not as sure about the DC-DC converter and charger. The DC-DC converter switches the 360VDC to make 14VDC. The charger rectifies the J1772 inlet port to produce 336VDC (240VDC x 1.4= 336VDC) which it switches to make 360VDC to charge the battery. Since both are switching over 300VDC the IGBT might be first choice; however, I know they can be lighter and smaller with higher switching frequency MOSFETs. I would choose a higher efficient (but more costly?) MOSFET design. Who knows? Do the DC-DC converter and charger use MOSFETs?
Details:
http://www.electronicproducts.com/A..._Transistors/MOSFET_vs_IGBT.aspx#.U7rKZqicxvg
http://electronicdesign.com/interconnects/igbts-or-mosfets-which-better-your-design
For the technically minded, here is a nice simple article in switching device tradeoffs.
http://chargedevs.com/features/a-closer-look-at-the-semiconductor-switch/
Executive summary:
MOSFETs are preferred in low voltage or high switching frequency applications, but the lack of minority carriers means conduction losses increase rapidly with blocking voltage (a square function). The MOSFET is better for most “hard-switched” DC-DC converter and chargers.
IGBTs are preferred at higher voltage/higher power applications with lower switching frequency. The IGBT is better for most motor controllers.
The i-MiEV:
I'm sure the MiEV uses IGBTs for the motor controller, but I'm not as sure about the DC-DC converter and charger. The DC-DC converter switches the 360VDC to make 14VDC. The charger rectifies the J1772 inlet port to produce 336VDC (240VDC x 1.4= 336VDC) which it switches to make 360VDC to charge the battery. Since both are switching over 300VDC the IGBT might be first choice; however, I know they can be lighter and smaller with higher switching frequency MOSFETs. I would choose a higher efficient (but more costly?) MOSFET design. Who knows? Do the DC-DC converter and charger use MOSFETs?
Details:
http://www.electronicproducts.com/A..._Transistors/MOSFET_vs_IGBT.aspx#.U7rKZqicxvg
http://electronicdesign.com/interconnects/igbts-or-mosfets-which-better-your-design
