Finding an optimal MOSFET for 55 V 60 A BLDC driver (ESC), No Parallelin DRV8323 - Page 1
Forum section: electronics / projects

author: satyamfifa
author_rank: Regular Contributor
timestamp: May 26, 2018, 11:25:01 pm
content: Dear All,I trying to build an BLDC Driver (ESC) with specification, Voltage is Aprox 48V from a battery so max 55V, Current consumption is about 60A RMS with Field Oriented Control capability, I want to use DRV8323 (source 1A and sink 2A ) (I know it's less but the aim to find the most optimal MOSFET for this gate drive) According to my previous research:1.https://www.eevblog.com/forum/projects/60-ampere-bldc-pcb-design-and-routing/2.https://www.eevblog.com/forum/projects/lost-trying-to-calculate-switching-time-of-power-mosfet/There are 3 Major factors to consider:1. Conductive losses: which is mainly dictated by Rds(on) of MOSFET.2. Switching losses: which is mainly dictated by Qgd of MOSFET, but it can vary depending on fundamental switching frequency.3. Losses due to avalanche: Here were it gets more complex, Avalanche can be unpredictable because they happen because of the stray inductance, which is hard to estimate before hand, I understand that avalanche handling capability are mentioned in the datasheet as EAS and EAR. However I thinking wouldn't it better if a MOSFET with the higher break down voltage (80V) is selected which would prevent the MOSFET going in the Avalanche mode in the first place.Therefore concluding the above three, I think the Infeneon's IPT012N08N5 with Rds(on) of 1.2 milliohm MAX, Qgd of 37 nC (TYP) and 56 nC (MAX) and Breakdown voltage of 80V (MIN), I believe it could this could be a much better MOSFET as it could prevent all three kinds of losses.I don't understand Infeneon's StrongIRFET avalanche ratings they are designed specifically for handling avalanches in BLDC drives but I don't find their avalanche ratings any better. Therefore maybe someone can be the Devil's advocate for the IPT012N08N5 decision and suggest a even better MOSFET.Another question: I have never seen a Field Oriented Control capable driver with parallel MOSFETs, I wonder why is that, I understand Field oriented control requires shunt resistors to measure current, maybe someone can shed light on this.Regards,Sparsh

author: satyamfifa
author_rank: Regular Contributor
timestamp: May 30, 2018, 08:05:37 am
content: anyone?

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 30, 2018, 11:00:44 am
content: https://www.digikey.com/products/en/discrete-semiconductor-products/transistors-fets-mosfets-single/278?FV=ffe00116%2C98004f3%2C98004fe%2C9800515%2C9800599%2C98005b8%2C98005c4%2C98005c5%2C98005e4%2C98005f9%2C9800612%2C980061f%2C98000a1%2C9800674%2C9800677%2C980067c%2C9800698%2C98006b3%2C98006e4%2C9800726%2C98000bd%2C980080b%2C980085e%2C9800873%2C9800891%2C98008a0%2C98008b9%2C98008c6%2C98008db%2C98008e5%2C9800919%2C980093a%2C980093b%2C9800959%2C9800964%2C980098d%2C9800a00%2C9800a1e%2C9800a3b%2C9800a5e%2C9800ab3%2C9800ac2%2C9800ac8%2C9800aea%2C9800b03%2C9800b23%2C9800120%2C9800b43%2C9800bee%2C9800ce4%2C9800d72%2C9800d73%2C9800dc5%2C9800e25%2C9800e62%2C9800ec7%2C9800ed2%2C9800ef9%2C9800eff%2C9800f1b%2C9800f5c%2C9800f5d%2C9800f69%2C9800f9a%2C9800f9d%2C9800fbb%2C9800fbc%2C9800fc3%2Cmu55V%7C2068%2Cmu59V%7C2068%2Cmu60V%7C2068%2Cmu65V%7C2068%2Cmu68V%7C2068%2Cmu70V%7C2068&quantity=&ColumnSort=2068&page=1&k=fet&pageSize=25&pkeyword=fet