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wich mcu for motor controller

Discussion in 'Electronic Design' started by colin, Nov 3, 2006.

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  1. colin

    colin Guest

    Hi there,
    I think I need a bit more than a pic16fxxx for my motor controller,
    pic16 seems a bit limited not having hardware maths,
    the motor is either going to be 2 or 3 phase with 3 or 4 rotor pole pairs
    with proportional hall sensors detecting the rotor poles,
    variable speed from realy slow upto 100k rpm,
    with pwm control proportional to speed and position as well at lowish
    maybe need timing adjustment at 100k rpm not sure but need to be able to
    just in case, as well as speed control.

    The power side will be seperate.

    I also need to do a few other data logging things too, and drive a second
    slow speed positioning motor.
    but I might use a second MCU.

    There seems to be quite a few MCU wich are tagged motor controller with
    4 dedicated pwm outputs wich would seem to make things realy easy,
    with quadrature position sensing too
    and some with respectable computing powers, wich would make my time a lot

    Im looking at the dspic30f6xxxx range atm but the data sheets lists the
    range of development stuff but none of wich seems to specify its suitable
    for the dspic30.

    Theres too much stuff to keep wading through.

    Are there any nice solutions with nice cheap/free development environments
    and with dev/demo boards cheap enough so I can use so i dont have to
    make a pcb for the mcu wich tend to be hard to solder packages ?

    Maybe someone has made avilable such a general purpose versatile
    programmable motor controller ?

    Colin =^.^=
  2. linnix

    linnix Guest

    I would use an AVR with 4 PWM outputs and an ARM for computations.
  3. colin

    colin Guest

    Cool thanks il have a look at that, is there a good place to start ?
    would it be very expensive to jump in with a dev/demo system that would do
    the job easily?
    Its just for some eqpmnt for an experiment but might wel get used for other
    things too.

    Colin =^.^=
  4. Guest

    There are several 16 bitters made for the motor inverter market.
    Hitachi, mitsubishi and fujitsu are a good place to start.
  5. nospam

    nospam Guest

    MPLab supports dspic30s, including in circuit debug with the cheap ICD2
    pod. ASM30 for assembly programming and C30 for C programming.

    C30 costs the rest are free.
  6. I did a control using the PIC18F series (one with 4pwm) and it works a
    treat. Coupled it to an IR IRAMS controller. Dad uses it now.
  7. linnix

    linnix Guest

    Not too expensive. We use an AVR165 ($5) and LM3S101 ARM ($3) in a
    project. The 20MHz ARM can run a couple of FFT per second and sample
    at 250KHz (top of the line at 50MHz for 1MSPS). The AVR can run wider
    voltage range (1.8V to 5.5V) and is perfect as the power controller.
    We can set you up with a demo system.
  8. colin

    colin Guest

    Thanks, I looked on ebay and found a ADUc7024 based ARM development board
    3phase 6 op pwm, 2 dac etc ... lots of adc wich is prob a lot more than il
    need but il be able to use it for all sorts probably.
    $50 wich doesnt seem bad its the cheapest one,
    interestingly the pwm outputs are able to be modulated so a transformer
    isolater can be used to drive the fets.

    theres a few others too not made up my mind yet,
    it needs a jtag for debuging, not sure if its needed for code download
    unless the bootloader is 100% reliable,
    the usb jtag by the same seller seems rather expensive considering other
    jtag leads are virtualy straight conections to the parallel port, or if its
    needed for one click make/download.

    is the dev software available for free include a c compiler ?

    Colin =^.^=
  9. I've used serial bootload for it. With an adapter, LPC21ISP and a
    simple 0.1" pin centres header you can download and observe via the
    serial port w/o laying hands on the board. I doubt the developboard it
    wired up for it though. Eay enough to add if it has a prototyping area
    if you desire though.

    I've some pointers to the interface and sw here Just
    scroll down past the product description.

  10. joseph2k

    joseph2k Guest

    And i thought that 100k rpm was going to be out of reach for inexpensive uC.
    I was going to suggest an FPGA approach, kit and tools under 100 USD.
  11. colin

    colin Guest

    well maybe 100krpm is a bit optimistic not least for the bits that are doing
    the rotating,
    but I dont want the electronics to be the limiting factor,
    its a 1M long 6mm dia shaft, with nothing but a couple of optical devices at
    each end.

    Ive had to put more bearings on as the shaft wobbled like mad at 10krpm but
    now the grease in the bearings slows it down to 3krpm so i gues il take the
    grease out.

    one motor with a short shaft goes easily to 30krpm (an old disc drive
    motor - 3 phase) but only has a 3mm spindle.
    so im using the parts of a DC fan motor as its easier to make it sit in the
    middle of the 6mm shaft.
    atm the proportional hall sensores feed directly into the dual full bridge
    mosfet driver via a class d type pwm stage.
    interestingly the fan motor is 2 phase with 1 pole pair per phase on the
    yet the rotor has 2 pole pairs too, seems to have some sort of phase lag
    device much like the shorted turn on a single phase induction fan motor, it
    makes for a more inefiecient and noisy motor than needed, I took a couple
    more fans apart and seems they are all like this.

    I remagnetised it now with 3 pole pairs, and rewound it. I might need a more
    power than it can give though.
    it needs to be able to slide the long shaft through the middle wich makes it
    difficult to use most readily available motors.

    I might settle for the dspic30f2010 as this seems ok, its got 3phase pwm
    with 6 outputs, wich will drive my dual full bridge or a 3 phase bridge, its
    hardly any more expensive than the 8 bit ones.

    Are there any in circuit debuggers wich will work with the cheap 'com84'
    rs232-icd port type hardware ?
    winpic works great for downloading with it.

    Colin =^.^=
  12. Terry Given

    Terry Given Guest

    why not get a "manly" chip, like the TMS320F2811. 150MIPS, 12-phase PWM,
    83ns ADC, 128Mb flash etc and about US$10. hardware interlock, desat
    inputs, the works.

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