Drive a 16A Hydraulic Pump with an Arduino Uno Rev.3

Other Hardware Motors, Mechanics, Power and CNC
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Hello, everyone,

I am developing an Automatic Pilot System for my pleasure craft, made of two Arduino Mega2560 and four Arduino Uno Rev.3.
One Mega handles the "Mode Control Panel" with some buttons, encoders and displays, one Uno receives NMEA sentences from the ECDIS, which is the navigational card plotter device. Than we have a Mega that carries out the calculation of a rudder angel to steer. Two further Unos drive "Command Units" where you can steer the vessel manually, and last but not least one Uno drives the rudder.

The rudder control system on the vessel is a powerless hydraulic system, that means the helm wheels are connected to plunger pumps, that gives its pressure to a cylinder connected to the rudder. Also there is an electric hydraulic pump, that can turn both directions and also gives its pressure to the cylinder.

This electric pump is said to use a 16A load to its driver, so my task now is to develop a driver unit, that takes a PWM signal for each direction to turn and drives the pump's engine with this PWM signal.

I have made a schematic on how I think it should work, but before I blow up some devices I thought I ask if someone could put an eye on it and tell me if I might mess up...

Edit: It might be useful if I mention what the connectors are:
K1 is the 12V input, K2 is connected to the pump engine, and K3 is the input from the Uno.
One pin for each direction and GND.

Thank you for any hints.
Joerg

Motortreiber.pdf (109 KB)

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I always expect SMOKE when someone uses a guess on current use to design something.
Paul

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I also do so, but if the datasheet of the engine mentions 16A and the MOSFET handles 59A I should be save.

4

if the datasheet of the engine mentions 16A

Of what use is the word mentions? Post a link to the data sheet.

Keep in mind that the startup/stall current of a brushed D.C. motor is typically 5x to 10x the running current.

I doubt very much that the driver circuit will work as you expect. Be sure to wear safety goggles when testing it. Much better: buy a professionally designed driver that can easily handle the stall current of the pump.

5

jremington:
...Post a link to the data sheet.

Here it is:

That's all information provided by the manufacturer. They also prescribe cable strength of 2,5mm².
At least the pump moves a rudder with little resistance.
Can you tell me why you doubt the circuit will work?
Regards
Joerg

6

Are you completely confident the hydraulic pump rotates both directions, or does the pump rotate continuously and valving directs the pressure on one of two possible directions?
Paul

7

The circuit diagram you posted cannot possibly work, because it has very serious errors.

Even if the errors are corrected, I don't think the design will work, because the gate drive is inadequate, and the transistors are inadequate for the current requirements.

I take this data sheet entry to mean that the maximal steady state current of your pump is 15A.

Stroom bij nullast : 6,5 A 4,0 A 7,5 A 4,8 A 9,0 A 6,0 A
Stroom maximaal : 9,5 A 6,0 A 12,5 A 6,9 A 15 A 8,9 A

If so, the start/stall current is MUCH higher, maybe 50A or more.

8

I've already given up and ordered a driver device that can be controlled by Arduino and stands 89A. For ~30 Euros I can't build up my own...

Thank you all.

9

A wise decision! That is what I chose to do for an electric scooter design.

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For posterity, using an opamp to drive MOSFET gates is not the way to go, probably too slow to prevent
switching losses becoming intolerable, and the LM358 can't drive up to the positive rail anyway, so the
p-FETs would never fully switch off.

The correct chip to use to drive MOSFETs is a MOSFET driver chip, unsurprizingly!

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