Hi all, Please excuse the long post, but there is so much I need to get sorted.
i'm working on a project that has a brushed 12V DC Motor, and believe it or not, two choices of speed controller.
One is an H-Bridge controller that runs off a manual switch/pot for local control, and the other is a MOSFET PWM driven by an Arduino Nano, controlled by an EV1527 learning receiver, for remote control. The motor could be changed to brushless, but they have been purchased in quantity.
I have to be sketchy about the application, as it is a commercial product, and patents will be applied for, but I have attached the schematic.
Now I have the problem that when the electronics is all packaged in its aluminium tube housing, electrical noise is affecting the 433MHz RF signal for the Arduino control.
I am attacking the problem in several ways.
1. Add a grounded tinned copper shield around the EV1527 module and the Arduino
2. Modified the PCB layout to minimise the cable length from main PCB to Motor.
3. Add LC filtering to the MCU supply line.
4. Add LC filtering to the motor (I have opted to do this on the motor terminals, to try to keep the noise away from the feed wires)
5. Experiment with the Arduino PWM frequency, which is currently 490 Hz, whereas the H-Bridge frequency is 21kHz. I can go to 3.9kHz or 31.3kHz. The traces show the waveforms across the motor terminals for both controllers, you can clearly see that the H-Bridge is much cleaner, so going to a higher frequency must suit the motor better.
So I have to add LC filtering to the motor to try and squelch the noise to a level that the EV1527 can cope with, and following recommendations from Kerry D Wong's "A Short Guide On Motor Electrical Noise Reduction" have designed a PCB to add to the motor rear-end containing the necessary components. I've obviously gone for the dual choke/capacitor scheme, as one of the controllers is an H-Bridge, and thought I had chosen suitable 10mH inductors but I have noticed they have a high DC resistance of several ohms, which I don't believe will be acceptable in this application.
Looking around for that sort of inductor with low DC resistance, I am finding that they are all way too large to be usable in this project, they would even be too big for the main PCB. But I don't wan to put them there, as the motor wiring is the interference culprit, so want to kill it at the motor.
I would be grateful for any suggestions or corrections, I have to nail this interference issue.
TIA
i'm working on a project that has a brushed 12V DC Motor, and believe it or not, two choices of speed controller.
One is an H-Bridge controller that runs off a manual switch/pot for local control, and the other is a MOSFET PWM driven by an Arduino Nano, controlled by an EV1527 learning receiver, for remote control. The motor could be changed to brushless, but they have been purchased in quantity.
I have to be sketchy about the application, as it is a commercial product, and patents will be applied for, but I have attached the schematic.
Now I have the problem that when the electronics is all packaged in its aluminium tube housing, electrical noise is affecting the 433MHz RF signal for the Arduino control.
I am attacking the problem in several ways.
1. Add a grounded tinned copper shield around the EV1527 module and the Arduino
2. Modified the PCB layout to minimise the cable length from main PCB to Motor.
3. Add LC filtering to the MCU supply line.
4. Add LC filtering to the motor (I have opted to do this on the motor terminals, to try to keep the noise away from the feed wires)
5. Experiment with the Arduino PWM frequency, which is currently 490 Hz, whereas the H-Bridge frequency is 21kHz. I can go to 3.9kHz or 31.3kHz. The traces show the waveforms across the motor terminals for both controllers, you can clearly see that the H-Bridge is much cleaner, so going to a higher frequency must suit the motor better.
So I have to add LC filtering to the motor to try and squelch the noise to a level that the EV1527 can cope with, and following recommendations from Kerry D Wong's "A Short Guide On Motor Electrical Noise Reduction" have designed a PCB to add to the motor rear-end containing the necessary components. I've obviously gone for the dual choke/capacitor scheme, as one of the controllers is an H-Bridge, and thought I had chosen suitable 10mH inductors but I have noticed they have a high DC resistance of several ohms, which I don't believe will be acceptable in this application.
Looking around for that sort of inductor with low DC resistance, I am finding that they are all way too large to be usable in this project, they would even be too big for the main PCB. But I don't wan to put them there, as the motor wiring is the interference culprit, so want to kill it at the motor.
I would be grateful for any suggestions or corrections, I have to nail this interference issue.
TIA