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Hi,
My two cents about what you should look for to make your life easier:
-A Microcontroller with hardware support for PWM generation of at least 3 phases. If it is able to insert dead-time between on leg high and low side transistor, much better, since the driver you use doesn´t do this.
-If...
Hi,
I am trying to make a custom BLDC motor controller work. It uses the six-step conmutation schema as well as hall sensor-based feedback.
It uses a IR2110 gate driver (one for each phase). Since it does not spin my motor (1 pole per step = just 6 poles) I started to measure the waveforms at...
It is apparently a limitation of the MPLABX simulator and the PIC18F series. It does not support the Motion Feedback module. Tested in a real circuit and it works.
There is no circuit, I am using the MPLABX simulator. I think there are no internal pullups in PORTA, which is the one linked to the Motion Feedback module
The MCU is the pic18f4431.
When I originaly posted I forgot to set the Pins to Digital (they were in their default status, as Analog). But I recently solved that with no effect. ISR is still not triggered. The code is now like this:
TRISAbits.TRISA2 = 1;
TRISAbits.TRISA3 = 1...
Hi,
I Am trying (for now just using the MPLABX simulator) to trigger an interrupt each time any of the associated PINs (CAP1,2 & 3) changes state.
If I configure the MCU this way:
TRISAbits.TRISA2 = 1;
TRISAbits.TRISA3 = 1;
TRISAbits.TRISA4 = 1;
T5CONbits.TMR5ON = 1...
I finally managed to devise how to do this in the MCU.
Changing from complementary to independent mode (and the other way around) is in fact possible at any time BUT the phase must have PWM on it (it wont work if it is overriden to a fixed value via OVDCON registers, which is what I was trying...
In the end, I decided to use the "SD" pin of my gate driver chip (IR2110) to completelly disable each phase whenever It must be (just before changing commutation step, using uno digital output from the MCU). I was unable to find a way to do what I want with the PCPWM module.
Regards.
Hi,
120 degree phase shift is OK. The PIC can be any PIC18F, It´s just that the one I currently have is the PIC18F4431.
The issue I have is related to the way I want to drive the phases (Specifically, at the moment the PWM for the active phase if OFF. For instance, if high side MOSFET for "A"...
Lets focus in the first step:
Phase "A" -->PWM
-PWM to the high side MOSFET (PWM1).
-Complementary PWM to the low side MOSFET (PWM0) + dead time.
Phase "B" -->no PWM
-Low side MOSFET on (pin PWM2).
-High side off (pin PWM3).
Phase "C" -->no PWM
-Low side MOSFET off (pin PWM4).
-High side off...
You mean the code?
Well, it is a bit crude right now, it just configure the registers , set the commutating table and change between the six steps each second. PWM duty cycle fixed at a low value.
This is it:
#include <xc.h>
// #pragma config statements should precede project file includes...
Hi,
I am Trying to build a BLDC motor controller with the PIC18F4431 MCU. My plan is to use the six step sensorless trapezoidal commutation. Complementary and unipolar PWM, to be precise. The reason I chose this is to use synchronous rectification instead of simplt using the MOSFET intrinsic...
I was so obsessed with gate discharge path that I did not considered the drain to source capacitance.... thanks, I will change the dummy load.
Kind Regards.
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