Prius motor voltage

AC, DC, amps, volts and kilowatt. It's all discussed in here
Post Reply
Martin
Noobie
Posts: 18
Joined: Sun, 16 Nov 2008, 03:46

Prius motor voltage

Post by Martin »

Looking at the last three prius battery/motor voltage sets, the battery has crept down from 288v (ish) to 240v (ish) to just over 200volts. Meanwhile, the motor in the third (200ish volt) version is rated to 500 volts.

Considering for a given power rating, voltage is the way to go over amps, how have the toyota engineers chosen to bump up the battery voltage like that - efficiently?
250 km's or bust

Tritium_James
Senior Member
Posts: 683
Joined: Wed, 04 Mar 2009, 17:15
Real Name: James Kennedy
Contact:

Prius motor voltage

Post by Tritium_James »

There's a ~50kW bidirectional boost converter built into the motor controller power electronics box.

Martin
Noobie
Posts: 18
Joined: Sun, 16 Nov 2008, 03:46

Prius motor voltage

Post by Martin »

Ok, is there more to it than using electronics to add to the +200 supply already available by using a reversed -200v from the same battery pack? (I realise that still only comes to 400ish volts...)

(And is this method used in other available controllers?)
250 km's or bust

User avatar
coulomb
Site Admin
Posts: 3831
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Prius motor voltage

Post by coulomb »

Martin wrote: Ok, is there more to it ...
Yes, it's a standard half-bridge converter (buck/boost). Two switches, controlled appropriately. By varying the PWM duty cycle, you get buck, boost, or pass through, bidirectionally.
(And is this method used in other available controllers?)

As far as I know, this is unique, or very rare. I think they went to some trouble to ensure that it was still efficient when not up-converting (e.g. motors need < 200 V).
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
160 W solar, 2.5 kWh 24 V battery for lights.
Patching PIP-4048/5048 inverter-chargers.

Martin
Noobie
Posts: 18
Joined: Sun, 16 Nov 2008, 03:46

Prius motor voltage

Post by Martin »

So it is worthwhile going to all this trouble to supply a motor with a higher voltage than the battery pack can provide on its own.

Any chance of a reference to the buck/boost process for a better understanding? (if it's not available commercially anywhere)
250 km's or bust

antiscab
Senior Member
Posts: 2499
Joined: Mon, 26 Nov 2007, 05:39
Real Name: Matthew Lacey
Location: Perth, WA

Prius motor voltage

Post by antiscab »

Martin wrote: So it is worthwhile going to all this trouble to supply a motor with a higher voltage than the battery pack can provide on its own.


I would say no, the increased cost and weight of a buck boost circuit before the main controller power stage (this will be the size of your controller and your motor windings) in most cases outweighs the increased sized and cost of the BMS to deal with a larger number of smaller cells.

the wikipedia write up is good for getting a basic understanding of how a buck converter and boost converter works.
buck converter write up on wikipedia
boost converter wrtie up on wikipedia

Matt
Matt
2017 Renault zoe - 25'000km
2007 vectrix - 156'000km
1998 prius - needs Batt
1999 Prius - needs batt
2000 prius - has 200 x headway 38120 cells

Post Reply