3.6 V ---> 72 V possible?

[optimistx]

Assume LiIon battery cell giving nominally 3.6 V (2.8V--4.2 V), 10 Ah,
max discharge 30 Amperes temporarily, continuous operating current 3 A.,
pulse discharge current 150 A.

Is it possible to easily design an inverter or boost converter for
one's own use to give the dc output 72 V with high efficiency? (= 20
times the input voltage) or is this too high a ratio? (protections
needed for commercial products can be omitted)

A detailed circuit diagram with a shopping list ? Which breadboard kit
to use in experiments? Or is it impossible to cope with wire inductances
in usual breadboard kits? A microprocessor and software based solution
is ok.

The output will be used to control a small permanent magnet brushless
motor (which can take 72 V nominal), so the ripple magnitude is not a
problem.

 

[Chris Holmes]

optimistx wrote:

Assume LiIon battery cell giving nominally 3.6 V (2.8V--4.2 V), 10 Ah,
max discharge 30 Amperes temporarily, continuous operating current 3 A.,
pulse discharge current 150 A.

Is it possible to easily design an inverter or boost converter for
one's own use to give the dc output 72 V with high efficiency? (= 20
times the input voltage) or is this too high a ratio? (protections
needed for commercial products can be omitted)

A detailed circuit diagram with a shopping list ? Which breadboard kit
to use in experiments? Or is it impossible to cope with wire inductances
in usual breadboard kits? A microprocessor and software based solution
is ok.

The output will be used to control a small permanent magnet brushless
motor (which can take 72 V nominal), so the ripple magnitude is not a
problem.

Hi optimistx,

Yes, it should be possible. You could try the LT1170HV from Linear
Technology. The datasheet will give you some idea of the circuitry
involved. I suppose the biggest question is the rating of the brushless
motor. 72V sounds like a big motor to me, but that's not really my area.

Chris

 

[Rylos]

Should be possible but the thing that I would be concerned with is the
current draw from the battery. Remember that input power = output power with
a switching power converter ideally speaking (minus some losses of course).
If your battery is 3.6V nominal with a 3A continous current then that gives
a maximum continous power average of 10.8W. With a 72V motor on the output,
it should draw no more than 150mA continous or else you'll be pulling more
than 3A from your battery which may smoke it. Make sense?

-Dave

"optimistx" <optimistxPoista@hotmail.com> wrote in message
news:d9d4d.175$Kr3.47@reader1.news.jippii.net...

Assume LiIon battery cell giving nominally 3.6 V (2.8V--4.2 V), 10 Ah,
max discharge 30 Amperes temporarily, continuous operating current 3 A.,
pulse discharge current 150 A.

Is it possible to easily design an inverter or boost converter for
one's own use to give the dc output 72 V with high efficiency? (= 20
times the input voltage) or is this too high a ratio? (protections
needed for commercial products can be omitted)

A detailed circuit diagram with a shopping list ? Which breadboard kit
to use in experiments? Or is it impossible to cope with wire inductances
in usual breadboard kits? A microprocessor and software based solution
is ok.

The output will be used to control a small permanent magnet brushless
motor (which can take 72 V nominal), so the ripple magnitude is not a
problem.