ECE 110/120 Honors Lab Section : Testing Use of Direct Drive on Brushless Electric Motors

Final Report

Qingran Wang

Umang Chavan

Jason Hwang

Electric Skate Project: Testing Use of Direct Drive on Brushless Electric Motors

Project Description:

This project aims to create a new transportation device for people to use

Completed so far is the first prototype with functional motorized wheel

Problems:

Motor is not powerful enough

Redesign transmitter to be used with smartphone application

Designing brakes with instantaneous stopping

Designing strapping system for feet

The problem we will focus on this semester is the power of the motor

Current Motor's Specification

What we will test this semester:

The amount of load the motor can handle

How fast the motor can run under various loads, maximum speed

Measuring torque

Measuring Maximum voltage and current

September 28, 2015

We researched more on the parts that are required in order to make the skate apparatus work

We learned more about brushless motors and the electromagnets that enable it to work

We created a high level block diagram that outlines the way the apparatus will function

October 5, 2015

We plan on testing the first iteration of the apparatus, the parts for which we have currently

We researched different types of electronic speed control that can handle above 120A and between 22.2 to 44.4V

Therefore, an initial parts list is not available because all parts are owned

We worked on the low-level block diagram in the lab notebook

We plan on testing current iteration next week

October 12, 2015

Begin listing specifications to test on motor

Motor Specifications:

1) Torque

2) Revolutions per Minute (RPM) under Different Loads (different weights)

3) Revolutions per Minute at Different Voltages

4) Acceleration under different Loads/Maximum Load

Ultimate Question:

Person = 70-90 kg (155-200 lbs)

Speed = 12-14 meters per second (mps) (25-30 mph)

Distance = 5-8 km (3-5 miles) per charge

Calculations will be provided in a separate document

October 19, 2015

Presented our current progress to our fellow classmates and discussed obstacles that we face so far

Researched the possibility of building a custom electronic speed control with higher voltage tolerances

Found what's inside an ESC:

Open Source ESC Website: http://vedder.se/2015/01/vesc-open-source-esc/

Discussed the strapping design that will be implemented on the apparatus

October 26, 2015

We discussed what we are going to be doing for subsequent classes

We are researching in depth about how the electronic speed control functions, starting from high-level down to low-level

November 2, 2015

Looked at parts of electronic speed controller:

1. Micro controller
2. MOSFET driver / buck converter / current shunt amplifier
3. MOEFETs
4. Inverters
5. Rectifiers

We have decided to focus specifically on the 

 DRV8302 3-Phase Brushless Motor Pre-Driver with Dual Current Sense Amps and Buck Converter (PWM Control)

We will understand how these parts work and try to make one of these circuits using a breadboard if possible.

http://vedder.se/2015/01/vesc-open-source-esc/

http://www.ti.com/product/DRV8302/technicaldocuments

http://www.ti.com/lit/ds/symlink/drv8302.pdf

November 9, 2015

Began building three-phase Arduino circuit.

We plan on creating a circuit that lights three LEDs in waveform pattern, and connecting the output to our brushless motor as a replacement for our electronic speed control.

http://elabz.com/brushless-dc-motor-with-arduino/

November 16, 2015

We met with Andy Yoon who is specializing in motors and motor controllers. He gave us an example of a six-switch circuit that we can use to create a three-phase PWM that can theoretically drive our motor.

We located the pMOS and nMOS transistors needed to build the circuit and began understanding the logic behind how it works.

November 30, 2015

Alan created part of the 3-phase motor drive circuit over break, and we spent the rest of the time making the other half of the motor as well as creating the code for the arduino to run.