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180 v dc variable output required from 24 v dc

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Rohith reddy

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Hii everyone am doing a project in which I need a 180 vdc variable output,2A from 24 v dc Input

I need it transformer less
What is the best method to be used in low cost

I need variable 180 v dc from 24 v dc
To power a dc motor of
Input: 180v dc
Max current: 2.6 A
Power: 0.5 hp
 
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crutschow

Well-Known Member
Most Helpful Member
The converter will require an inductor at a minimum.

Note that the 24Vde supply will need to supply at least 500W (20A).
Is it capable of that?
 

ChrisP58

Well-Known Member
What method of output voltage control do you need?
- Manual potentiometer?
- Control signal from some other device, such as a microcontroller?
- Other?
 

ChrisP58

Well-Known Member
What type of output is the microcontroller?
- Voltage from a DAC?
- PWM signal?
- Serial data such as SPI, I2C or other signal that can drive a digital pot?
 

ronsimpson

Well-Known Member
Most Helpful Member
I want to see the data on the motor. The start up current might be huge.
This is a big project. If you have never built a switching power supply, this is not where to start.
 

spec

Well-Known Member
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Varying from 100 to 180v
Hi Rohith,

Thanks for the information.

This project is quite feasible from a technical point of view but, as the other members have stated, it is no small undertaking. Are you experienced in electronics, especially high voltage electronics with the associated dangers, and do you have the facilities to build the system?

Also, as the other members have said, we would need to know the characteristics of the motor, especially the start-up current. Can you tell us what the motor is for?

spec
 

ronsimpson

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Most Helpful Member
Spec, Rohith,
There is a requirement of no transformer. We need a inductor and maybe a transformer. If no "magnetics" then we need to know before we start. and why?
Most "boost" power supplies can not set the output to zero volts.
example: This boost supply can not go below 24 volts. Even when shut off. I think you will need to take the motor to zero volts by adding a switch or building a supply that can output zero.

Why no transformer? Do you need the motor at zero?
 

schmitt trigger

Well-Known Member
Hi Rohith,


Also, as the other members have said, we would need to know the characteristics of the motor, especially the start-up current. ?

spec
I've worked extensively with brushed DC motors.
The startup current is only limited by the armature resistance, which on a motor this size will be between 1 and 2 ohm.

Therefore all brushed DC motors must be soft started, either by a reduced voltage or a tapped resistor whose taps are sequentially shorted out.

I would assume that since this is a DC to DC conversion, the startup could be achieved by a current limit feedback.

Something that the OP poster has not told us is what type of DC motor it is. Is it Permanent magnet or does it have a separate field connection? If the latter, then a constant voltage field supply will be required.
 

spec

Well-Known Member
Most Helpful Member
I've worked extensively with brushed DC motors.
The startup current is only limited by the armature resistance, which on a motor this size will be between 1 and 2 ohm.

Therefore all brushed DC motors must be soft started, either by a reduced voltage or a tapped resistor whose taps are sequentially shorted out.

I would assume that since this is a DC to DC conversion, the startup could be achieved by a current limit feedback.

Something that the OP poster has not told us is what type of DC motor it is. Is it Permanent magnet or does it have a separate field connection? If the latter, then a constant voltage field supply will be required.
Yes ST,

A current limiting inverter will do the job.

I assume with a DC motor it is a balancing act between:
(1) Enough current to start the motor
(2) But not too much current that would damage the motor.

Off the top of my head, I would guess a current capacity, and thus limit, of 25A as a good starting point.

spec
 

ronsimpson

Well-Known Member
Most Helpful Member
Some thoughts:
Here is a typical boost power supply. From experiance; The motor will not get less than 24V. At startup massive current will flow from 24V to motor and saturate out the inductor. When the power supply starts up it will find a saturated inductor and not be happy.
upload_2016-12-9_16-10-22.png
This supply is very similar but starts out at 0V. It will not have a saturation problem at start up.
upload_2016-12-9_16-12-17.png
CoilCraft has a nice set of transformers that are 1:1:1:1:1:1.
This should work like a (24 to 60V) X 3 power supply.
The way this transformer is wound there is no need for snubbing on MOSFET or diodes. All that energy is captured.
If you choose current mode flyback this is simple, and I have made millions.
upload_2016-12-9_16-16-23.png
About 20 years ago I made many of these. It combines Flyback and Forward power supplies. I think I used voltage mode TL494 as the PWM.
Again; the way the transformer is wound, much of the AC losses are removed. I was able to run with a very fast PWM.
upload_2016-12-9_16-19-54.png
At this power level I would consider a forward power supply. Did not draw any.
 

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tcmtech

Banned
Most Helpful Member
I would either get a motor that matches the input voltage or use a common 24 volt power inverter and modify its output stage circuit to work as a PWM system opposed to being a AC output.
 

schmitt trigger

Well-Known Member
I would either get a motor that matches the input voltage or use a common 24 volt power inverter and modify its output stage circuit to work as a PWM system opposed to being a AC output.
Thanks tcmtech......you are the voice of reason whenever some of us start to stray away from reality.
24 volt (sorry, I had a typo), 1/2 hp motors are widely available. But I assume the OP already owns the 180 volt motor.
 
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tcmtech

Banned
Most Helpful Member
Thanks tcmtech......you are the voice of reason whenever some of us start to stray away from reality.
34 volt, 1/2 hp motors are widely available. But I assume the OP already owns the 180 volt motor.
Yea but I tend to really piss some people off with that sort of view towards getting things done in a practical efficient way. :oops:
 

schmitt trigger

Well-Known Member
An acquaintance has a saying:

-is it doing its intended function?
-no smoke or sparks are coming out?
-were you able to make at zero or very low cost?

Then, the project is a success
 

Rohith reddy

New Member
I've worked extensively with brushed DC motors.
The startup current is only limited by the armature resistance, which on a motor this size will be between 1 and 2 ohm.

Therefore all brushed DC motors must be soft started, either by a reduced voltage or a tapped resistor whose taps are sequentially shorted out.

I would assume that since this is a DC to DC conversion, the startup could be achieved by a current limit feedback.

Something that the OP poster has not told us is what type of DC motor it is. Is it Permanent magnet or does it have a separate field connection? If the latter, then a constant voltage field supply will be required.
 
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