Power management

Posted on September 24, 2014 at 10:26Hi,I'm controlling my PMSM at zero speed. While I'm trying to move its shaft I don't want my motor to generate its maximum torque to resist my movement but the limited one. Everything went fine with classic control, but as soon as I tried to limit it's torque -- by limiting outputs of speed and Q-current PI controllers on some smaller values -- the motor started spinning (?!). I really have no idea how to accomplish described task, exept by limiting outputs of PI controlers Any suggestions?Thanks in advance! 

Posted on August 27, 2013 at 10:05I am experiencing problem with the current regulation of the L6472. We made 2 series of boards, one was fitted with L6474s, the other one with L6472s. The board has 8 channels, supply voltage is 24V / 3.3V, timing parameters are reset default, internal oscillator. The motor windings have 1.7Ohm, 3.6mH. The board has 4 layers of 35�m including solid planes for 24V and GND. Everything is fine for the L6474. With the L6472 the phase current jumps wildly close to the zero crossing of the microstep sequence. All channels are affected, but usually only one phase of each channel. No difference between predictive and peak current regulation. I have several ideas what could be wrong: 1) Current measurement influenced by some ground shift effect 2) Supply voltage too noisy 3) Suboptimal timing parameters I am wondering where to look first. #l6472-current-regulation #l6472-l6474-

Posted on September 18, 2014 at 17:37Hello!I bought 3 Eval-L9942 boards. I connected supply voltage (5V). Enable (connect to 5V) and a step clock (5V. 100Hz). The VS supply is 12V.The motor i have connected does not move. All outputs are at 12V constantly.I have connected a SPI interface (Aardvark) and read out the phase count register (it counts up).Have I missed something? I have no clue why the driver is not working.By the way, is it possible to read out the phase counter or change the motor direction without overwriting the phase counter?best regardsPhilippElectronics Design Engineer #motor-driver #l9942 #eval-l9942

Posted on August 29, 2014 at 03:19timer 1 output compare to generate Step output for stepper motorI am using timer1 channel 1 as output compare, to generate a pulse of variable period.Desire output – In the  beginning the output remain low for 4 ms(delay period) and then pulses of variable periods as  5.8, 3.6, 2.7,2.3, …. The desired time periods are stored in RAM. (Frequency range 170 Hz to 1.5 KHz)The timer clock is configured to 1 MHz frequency. The output mode is set to toggle mode and the polarity is set to active high. The capture compare interrupt is enabled. And the capture compare  register is set to delay period and then in next interrupt, the capture compare  register set to first period and next period will be updated after the one pulse is completed.The problem  facing is that the beginning delay period  is variable and sometimes miss

Posted on September 15, 2014 at 16:23I'm investigating using the L6470 for an multi-axis application. Please let me now if it is possible using SPI to position multiple motors according to a motion profile/position table at constant speed. i.e. implementing G-code control #l6470

Posted on October 22, 2013 at 20:37I've been quite successful at controlling the L6470 stepper driver chip from my embedded ARM processor for all features other than the sensorless stall detection feature. I'm hoping that I'm missing something and that someone can point that out to me. I've been all over this forum and every scrap of ST documentation I can get my eyes on.When I try to detect stalling, the detection threshold seems to be very sensitive; at one current setting the chip never detect any stalls, and at the next increment of stall threshold current the chip always shows stalling. This pretty much makes the feature unusable, so I'm not using it. I would really like to be able to use this feature, since we can't afford to put encoders everywhere. Also, it's one reason we picked the driver chip, so it will be disappointing if we can't use that feature.Am I missing something obvious? Is there m

Posted on September 03, 2014 at 09:59Hello!In my application I send GoTo(ABS_POS) commands when stepper motor is running at constant speed, when BUSY flag is high, so I'm sure that the target speed is reached. And everything is going well most of time, but sometimes (maybe 5-10% of total number of commands send) GoTo(ABS_POS) coommand acts like GoTo_DIR(DIR, ABS_POS)  command but with ''wrong'' direction and motor makes all 2^22 steps in opposite direction. So, GoTo(ABS_POS) doesn't act like a positioning in a shortest way. I have checked real signals many times to be sure that adrress of command is 0x60, not 0x68, one can see on attached picture.Are there any suggestions why this can happen and how one can avoid such problem?

Posted on August 03, 2014 at 06:34hello all :             I,recently?found that the formula about duty cycle  computation in the SW do not accord with that in the user manual . Sector ????TimePhA=T/8+?T+X-Z?/2 in the SW,however,Sector ????TimePhA=?T+X-Z?/2 in the user manual.what is meaning about T/8?Want to the help of the predecessors. Best wishes for you?????? #svpwm-duty-cycle-computation

Posted on August 14, 2014 at 03:20HiI'm designing a very compact quad VNH5050 12V Motor Driver board.I can optimize my design if I can pull-up the DIAG/ENA pins to 12V rather than the 5V Logic level.There is nothing else connected to these pins.  All I want is the bare minimum components.None of the specs seem to provide a max upper voltage limit for these open drain inputs.If I can use 12V, what is a suitable resistor value?Thanks.phil. #vnh5050-motor-driver-diag-ena

Posted on August 22, 2014 at 19:45HiI have developed about motor control by using L6482H. I follow circuit form reference circuit of L6482H Eval board (same part). Now I stuck at OCD failure. I have construct a new board follow Eval board. In Eval board is work correctly but my board not work it still OCD failure.Variable gate setup isIGATE = 32mATCC = 1750 nsTBLANK = 1000nsTDT = 375nsMOFET : STD25NF10T4Total gate charge : 55 nCWhat I do wrong? help plz

Posted on August 11, 2014 at 12:34hi,I am trying to drive bipolar stepper motor having 2.8A/phase current requirement using EVAL6208PD , after exceeding current limit of 1.5A drive IC get heated. Is it possible to drive bipolar stepper motor having current requirement 2.8A/phase using EVAL6208PD ?For my application , current requirement is 2.8-3A/phase then please tell me L6208 is suitable for it or not?? #l6208

Posted on July 30, 2014 at 19:04Could someone please explain how current is controlled on the L6207 via onboard PWM Current Controller?  Additionally, AN1762 APPLICATION NOTE indicated a constant current could be obtained through a simple voltage divider into Vref.  For example, I want to cap the current at 1.5A / phase, what type of PWM or voltage division would I need to implement? Thank you. #l6207

Posted on July 24, 2014 at 15:26Hello, I am posting this question that another user posted but there was no answer. Can anyone help?Can't reliably sense stalling using L6470 chipI've been quite successful at controlling the L6470 stepper driver chip from my embedded ARM processor for all features other than the sensorless stall detection feature. I'm hoping that I'm missing something and that someone can point that out to me. I've been all over this forum and every scrap of ST documentation I can get my eyes on. When I try to detect stalling, the detection threshold seems to be very sensitive; at one current setting the chip never detect any stalls, and at the next increment of stall threshold current the chip always shows stalling. This pretty much makes the feature unusable, so I'm not using it. I would really like to be able to use this feature, since we can't afford to put enc

Posted on July 22, 2014 at 21:47I have used EVAL6482H board to drive a stepper motor with a spec as followed,Operating voltage: 2.5vRated current/ phase: 0.49ASupply voltage: 20vI set the parameter as followed   Stepper.setParam(TVAL_HOLD, 0x02);   Stepper.setParam(TVAL_RUN, 0x02);   Stepper.setParam(OCD_TH, 0x08);   Stepper.setParam(CONFIG, 0xF788);   Stepper.setParam(GATECFG1, 0xC7);   Stepper.setParam(GATECFG2, 0x61);   Stepper.setParam(T_FAST, 0x47);   Stepper.setParam(TON_MIN, 0x07);   Stepper.setParam(TOFF_MIN, 0x1F);However, the return value from getStatus is 0xE403 ( 1110 0100 0000 0011), which indicates the undervoltage lockout and the f

Posted on August 17, 2014 at 10:32Gigi or Dino:        I met a strange question, motor parameter in STM3210E+ MB495 successfully entered the closed loop control. Now I redesign custom board,      The open loop mode debugging hardware correctly, when the switch into the normal mode, the motor open-loop liters of normal speed, but has the obvious noise, finally can not enter the closed loop mode, display the start-up Error.     The design of current sampling circuit, whether a rule? I oscilloscope display, amplifying the input 410mv 590mv circuit output amplification ratio 1.46, excuse me whether my T-noise with T-rise did not cause a good?

Posted on July 03, 2014 at 12:06We are working on a Medical Respirator equipment, for which we need to control the BLDC motor up to 60,000 RPM. To generate a speed of 60000 RPM, Space Vector Modulation PWM waveform main/base frequency shall be 4 KHZ. To have a smooth ripple free current/torque we need carrier frequency (Space Vector Modulation) shall be around 100kHz.Is it possible to generate this with coretex M4 or other controller 100 khz carrier frequency by SVM (Space Vector Modulation)Also at same time, it has to work on sensor less FOC as a close loop feedback for speed & to get optimum torque.For this it shall probably have current feedback from 2 motor coils.Also some other functions to satisfy respiratory systemPlease provide input Th

Posted on July 01, 2014 at 16:16Hi, I would like to control some small 3 Phase Induction motors with means of an analogue input and a potentiometer. I am looking at a V/Hz (Scalar) library that I could use with an ST processor. Can someone direct me to some example? Kind regards #3ph #induction #v/hz #acim

Posted on July 20, 2014 at 15:17Hello, I am looking for solution of SVPWM implementation for STM32F103 microcontroller. My application is AC motor frequency converter with U/F = const regulation. Best regards Andrzej #stm32 #3phase-motor #frequency-coverter

Posted on July 29, 2014 at 18:04Hi, I have a PMSM which I'm planning to run sensor-less. In case I run into problems with the sensor-less the motor I'm using also has a resolver fitted. I have a Resolver Decoder from analog devices so I'm wondering if I can read this over the SPI bus and input it to the FOC algorithim?  Or should i use the quadrature outputs from the resolver deocder IC and run these digital inputs into the STM32. If i had more time I'd play around with some sample and hold circuits and use the spare ADC to sample the SIN/COS signals coming from the resolver and decode them into position in the STM32. But that's a little bit off for now. Regards, David Powell

Posted on July 21, 2014 at 23:12i've been using the L6470 driver successfully but have noticed that i get step loss on the a and b bridge. the data sheet indicates that when this happens the appropriate bits in the status register get set. unfortunately, the data sheet does not indicate how this is being determined (if it has i missed it and so has a search through the .pdf file). sometimes these bits are cleared with or without an over current condition/under voltage condition. i am interested in knowing the reason for the step loss so i can take action to prevent this. if anyone can point me in the right direction i'd be thankful. scott #l6470 #step-loss

74168

Posted on July 22, 2013 at 15:39The question is related with the command word under the SPI protocol title. In this protocol uC should sent the command word to start protocol but I can not find the structure of this word. In datasheet the CFG_REG and DIA_REG registers are mentioned. But I can not understand the relationship between command word and those registers. If those register are sent instead of the command word, what we will be read? Could you help me?

Posted on August 08, 2013 at 20:17I want to control a stepper motor (http://pt.farnell.com/astrosyn/163/stepper-motor-1-8deg-5v/dp/9598650) with L9942 from ST.But i have some problem because the motor dont rotate uniformly (lose some step): My current profiles are (for DC = 111 - 1300mA):

Posted on July 09, 2014 at 04:41All - to save you a bit of trouble, here is what I found when I migrated my existing power board (discontinued by ST) to the new IHM023V2 power board:1) The connector pin-out to the STM32F10X-128K-EVAL is identical.2) However, the polarity of the lower IGBT drive signals is inverted.  This requires a software change to the polarity of the timer1 outputs.3) There is a flaw in the electrical design: the power bus requires high frequency decoupling at each of the bridge legs.  I used a 1uF, 200v ceramic cap across each of the 3 legs (drain of upper to source of lower; on the back of the board, right on the pins.  You may be able to go with a lower value at higher voltage but it NEEDs high frequency decoupling.  Not doing this will cause major EMI headaches.4) The jumper documentation for W16 is wrong.  It is obvious by looking at the copper on the PCB.  This jumper

Posted on July 01, 2014 at 01:11I'd like to enable the HardStop interrupt (i.e. SW_MODE = 0) when I home my motor and then disable it afterward so that subsequent moves do not trigger the interrupt.  Enabling the interrupt before I start homing via GoUntil and ReleaseSW work fine.  I checked the STATUS and CONFIG registers to confirm that there aren't any fault conditions, and that the SW_MODE bit is cleared when I send my command to enable the hardstop interrupt. Following any call to GoUntil or ReleaseSW, my command to set SW_MODE fails every time.  I get a NOTPERF_CMD error flag in the STATUS register and as expected, the SW_MODE bit is not set. So far, the only way I can set SW_MODE is *after* I use any HiZ command that disables the bridges.  However, this is not what I want because the axis will drop when the bridges are disabled! What is strange is that after homing, and after some u