Selection of DC motors for EV and controlling them

In summary: You can control the torque of a group of small DC motors with an H-bridge. You can use a single H-bridge to control all the motors or you can use multiple H-bridges to control each motor separately. You can also use a controller to provide a common torque reference for the motors.
  • #1
dave226
19
0
Hi, I am designing a small EV and I am looking forward to some guidlines regarding designing of H-bridge (torque) controller for controlling somewhat in between 6-8 permanent magnet brush DC motors , the overall power required from these motors is between 70 to 250 W, where 70 W is for propelling EV on normal surface and 250 W for peak/climbing uphill requirements.

Could you please suggest me the cheapest controlling design for such operation like
a) which type(with particular specs) of the bunch of small pmdc motors best fit for such operation (here the torque requirement is around 20 N-m) and i want to run all motors (say parallel combination) with a constant speed and controlled torque(preferable). The supply is 12V from batteries.
b) How to design and what is the best and the cheapest torque controlling method of these motors using H-bridge (like providing a common reference or say separate torque control of each motor and providing those with a common reference), the types of Mosfets and the heat sinks. Keeping in mind the availability in the market and the price factor too.

If you have any questions regarding this please ask me. All suggestions and ideas are welcome. Any help would be of great help!

Thanks!
Dave
 
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  • #2
You only need an H-bridge if you want to reverse motor rotation.
Pulse width modulation is probably what you need to look up for torque control.

If you're looking for motors to meet your specs you might try Digikey.com or Jameco.com.
 
  • #3
Thanks for the help No Time.

Well I am particularly looking for controlling the torque of bunch of small DC motors operating in parallel, with a torque of say 5N-m for each small motor.

I am also looking for some idea to control these motors using Hbridges in the cheapest and non bulkier way as i don't have much space to afford Hbridge controller for each motor separately or to provide torque reference separately to each motos, looking for something like controlling say 2 motors with a common Hbridge or something like that...


Thanks!
 

1. What factors should be considered when selecting a DC motor for an EV?

The main factors to consider when selecting a DC motor for an EV include the power and torque requirements, the voltage and current ratings, the size and weight limitations, and the cost and efficiency of the motor.

2. How can the power and torque requirements of an EV be determined for selecting a DC motor?

The power and torque requirements of an EV can be determined by estimating the weight of the vehicle, the desired acceleration and top speed, and the terrain and driving conditions. This information can then be used to calculate the required torque and power using basic physics equations.

3. What type of DC motor is typically used in EVs?

Most EVs use brushless DC motors, also known as BLDC motors. These motors offer high efficiency, low maintenance, and compact size, making them suitable for use in electric vehicles.

4. How is a DC motor controlled in an EV?

A DC motor in an EV is typically controlled using a motor controller, which regulates the voltage and current supplied to the motor. This allows for precise control of the motor's speed and torque, which is essential for efficient operation of the vehicle.

5. Can a DC motor be used for both propulsion and regenerative braking in an EV?

Yes, a DC motor can be used for both propulsion and regenerative braking in an EV. When the motor is powered, it provides torque to move the vehicle. When the vehicle is decelerating, the motor can be used as a generator to convert the kinetic energy of the vehicle into electrical energy, which can be stored in the battery for later use.

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