S12 / MagniV MicrocontrollersのトピックRe: What is the maximum current value available in S12ZVML-MINIBRD?

What is the maximum current value available in S12ZVML-MINIBRD?

cheolminlee — Mon, 03 Apr 2017 10:46:09 GMT

Hi.

I'm using S12ZVM-MINIBRD.

In the datasheet, it is indicated that current can be flowed up to 20A.

If I modify the circuit in which I sense the current, can I use a higher capacity motor?

Re: What is the maximum current value available in S12ZVML-MINIBRD?

RadekS — Mon, 03 Apr 2017 13:42:27 GMT

Hi CheolMin,

The S12ZVM-MINIBRD board was designed for +/-10A currents.

If you want to use higher loads, I would like to recommend:

Change shunt resistor for keep current sense signal in ADC range.
Mount silicone isolator and heatsink from the bottom side of PCB.

That should allow you to use a higher capacity motor with S12ZVM-MINIBRD board.

The heat sink should be rather bigger on (for example 5k/W) for playing on the table and lately, it may be optimized for smaller dimensions. The mounting hole at PCB should help you with proper heat sink holding.

I hope it helps you.

Have a great day,
Radek

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Re: What is the maximum current value available in S12ZVML-MINIBRD?

sohyunjang — Wed, 23 Aug 2017 02:28:41 GMT

Radek Sestak,

I wonder that if I change the shunt registor(to 1m ohm from 10m ohm), which parameter I modify (to reflect the modified shunt resistance)?

I use PMSM FOC Sensorless single shunt (AN5327) SW and MCAT tool.

thank you.

@ Radek Sestak

Re: What is the maximum current value available in S12ZVML-MINIBRD?

RadekS — Wed, 23 Aug 2017 07:22:27 GMT

Hi Sahyun,

The default load current conversion slope theoretically equals 0.125 V/ 1 A when we use a 10mOhm shunt and 40k/3.2k resistor ratio for the current amplifier.

Since reference voltage is 2.47V and voltage ADC reference 5V, the theoretical measurable range is something below +/-20A.

The default I_MAX definition in source code has value 15.0.

So, if you change shunt value to 1mOhm, the load current conversion slope will be 10 times smaller and the theoretical measurable range is something below +/-200A.

In that case, you should change the I_MAX value.

Of course, you should also change FreeMASTER Scale Variable FM_I_SCALE for correct display of current value in FreeMaster.

I hope it helps you.

Have a great day,
Radek