Endless Sphere

a non-EV related picture... not bad for a 750cc ICE (75 mpg in US units)

Watch out, the power rating values are only correct for the 100 Ohm example... with 50mA and the voltage you want to drop you can calculate the required rating. 40V and 50mA means you dissipate 2W, the resistor you use should be able to take this . When using 100 Ohm 0.5 W resistors for instance, yo...

Important remarks: R1: According to lebowskis video one page back this resistor ("tbd") should reduce the battery voltage to around 40 V at ~15 mA. A voltage drop of from 80 to 40V would mean a resistor value of 2.7 kOhm. Value in the kit: 220 Ohm (just a 3V reduction). Is this ok? R2: I think this...

Its a 5V chip (a 33EV from microchip), but for now it is all very early stages. Main thing to see is how it holds up under high throttle...

I have some opamp circuits, mainly to help the ADCs...

No chance... the hardware is just not there

:D my idea for getting full 360 info has worked, now I get reliable info about whether the phase is 0-179 or 180-359. So all combined I now get full 360 degree info (smooth, not just 6 levels) about the rotor position, sensorless at standstill. Processing time is around 10 to 20 msec for the first r...

Just spent 2 days programming, but ran into a problem with the 33EV I'm using... some obscure mistake in the silicon explained in the errata (but who reads those ?). Luckely there's other ways to skin a cat...

I have only a 50W iron, it just takes some time to heat everything up. Main thing to look out for is that the stuff on the opposite side of the board does not de-solder during this long heating time, so I had my L shaped heatsink there to keep things cool (clamped on with some clothes pins)

Is this the method where they measure inductance using the rise time of the current ? Don't you get only a 1 out of 6 info from this (so only 60 degrees resolution) ?

INFORM method ? I dont follow the literature and like to do everything myself, is more fun... at high speed I will switch over to backemf based sensorless of course.

I think the deatime is too short (set for 500nsec) to get anything useful out... plus there is phase current flowing to make the motor turn, effectively forcing what happens during deadtime... Putting a pattern on the I_imag was like the neutral light on my old Moto Guzzi, it was right about 80% of ...

Been very busy here with the saliency (?) based position detection, want to detect the rotor phase at standstill by measuring the differences between the motor inductances. And I want it good, just dividing the rotor position in 60 degree portions (like what you get with hall sensors) will not be go...

Dont forget to electrically isolate the FETs from the heatsink (by means of little heat pads) ! Also make sure you have the high and low ohmic resistors connected to the battery input at the correct place. The high value goes in the battery measurement line(via the 100nF), the low value in the power...

So this is from my controller:

Its the typical moving midpoint sinusoidal output... this does not mean its foc just that it is sinus out. The clou is that each if the waves looks kind of trapezoidal, but the DIFFERENCE between two voltages is sinusoidal (and with a max amplitude larger than what fits in the supply, which is the r...

Hm I don't know, 120kHz bandwitdth for the ACS parts seem good enough to me. 100k-erpm translates to 1.6 kHz, a pole at 120kHz would give a phase rotation of less than 1 degree. Cycle time of the algorithm is in the order of 30usec, so 4 usec delay in the current sensor doesn't seem relevant.

I would do 70% of max controller phase current. If it is a good controller it will probably not hit that level but back off earlier for other reasons...

But no reason not to start low and try anfew runs upping the field weakening, just dont expect impressive results before hitting the 70% mark.

I prefer proper current (magnetic field based) over resistive ones for the simple reason that if you want to keep the power dissipation the same, the higher the current rating of the resistor the lower the effective voltage you'll get. A 1W sense resistor for 1A can deliver 1V signal, a 1W for 1000A...

If you can set fieldweakening current, set it to 70% of max phase current.

Phase inductance should be different depending on rotor position. If that's enough info, and "easily" measurable, to know the exact rotor position, it's another story. Maybe it's also possible to use a phase to induce current into another phase and from that get position information. I imagine the ...

My goal is to have something which can sense the correct phase even when the motor is (mechanically) locked, so that the motor can provide torque in the correct direction against the mechanical lock. So no cheating by having a necessary small bit of movement to try and figure out which way we're goi...

lizardmech wrote: ↑

May 14, 2018 5:11 am

are you keep it secret in the hope of commercializing it or something?

yes

basically the circuit is a lowpass filter. With the VESC it allows you to filter out the PWM and see the sinusoidal content of the output.... though it should look more trapezoidal than sinusoidal. You need the motor parameters to calculate the correct timing advance for FOC. But mine does not need ...

Filtering and amplification... basically compensating for the ADC being only 10 bits