Testing three-phase brushless motor driver XXD2212 ESC

1. Brushless motor drive module

1. Basic Introduction

  High-speed brushless motors are now widely used in small unmanned quadcopters, power tools, and electric vehicle platforms. The following is a three-phase brushless motor drive module sent by Beijing Keyu.

▲ Figure 1.1 Disassembled three-phase brushless motor driver board

  On the back of the module, there are three MOS bridge circuits composed of six power MOS tubes. The circuit is proved by the single-chip microcomputer NUVOTON (Xintang) Xintang Technology MS51FB9AE controller introduction as the core, and then forms the driving circuit of the three-phase bridge circuit.

▲ Figure 1.2 Circuit of the controller part on the front of the driver module

2. External interface

  The motor drive module has three groups of interfaces outside:

External interface:

Motor interface: It is composed of three motor interface wires

Power supply: It is composed of red and black power cord

Control port: It is composed of three control lines similar to those of a servo.

2. Usage

  This module does not come with a dedicated instruction manual. From the appearance, it is similar to the brushless motor control speed control driver board aircraft model XXD2212 new Xida 30A electric adjustment high power. You can find the instructions for the use of the new Xida XXD2212 brushless motor interface.

▲ Figure 1.2.1 XXD2212 ESC

1. Interface signal control

  The microcontroller outputs a 1ms ~ 2ms square wave pulse with a repetition frequency of 20 ~ 100Hz, which is output to the throttle line (control line) of the ESC.

One-way ESC: 1ms means 0% throttle, 2ms means 100% throttle.

Bidirectional ESC: (with forward, reverse and brake), the standard is 1.5ms as 0 point, 1ms as maximum reverse throttle (100% throttle), used for braking or reverse; 2ms as maximum forward throttle (100% throttle), used for forward rotation.

  This control method is the same as the common servo control signal. The output is only related to the pulse width, not the pulse frequency.

2. Instructions for use

  Here are the instructions for using the electric drive sent by Science:

▲ Figure 1.2.1 Instructions for use of electric drive

  The explanation of the terms:

BEC: Battery Elimination Circuit, battery-free circuit. That is, the control end no longer needs a separate 5-6V control power supply, but directly uses the power supply after voltage reduction to provide it to the control circuit.

NIMH: Nickel Metal Hydride Battery;

LIPO: Lithium-ion polymer battery

▲ Figure 1.2.2 How to use the electric drive settings

§02 Driver Testing

  The following is a test of driving several brushless motors using the driver module.

1. Independent vehicle inertia wheel

  The flywheel of a unicycle is tested using the drive.

▲ Figure 1.3.1 Unicycle

1. Control signal generation

  The self-made ESP8266-12F module is used to generate a 100Hz multi-level control signal. The ADC of the ESP8266 is used to read the input voltage of the potentiometer and control the width of the output pulse to vary between 1ms and 2ms.

  Note: In order to use the 10kΩ potentiometer to input voltage correctly, you need to remove the 10kΩ resistor on the ADC port of the original ESP8266 circuit board.

▲ Figure 1.3.2 Pulse signal output by ESP8266 PIN5

#!/usr/local/bin/python

# -*- coding: gbk -*-

#============================================================

# TEST1.PY -- by Dr. ZhuoQing 2021-09-06

#

# Note:

#============================================================

from machine import Pin,PWM,ADC

import time

#------------------------------------------------------------

led0 = Pin(13, Pin.OUT)

adc = ADC(0)

#------------------------------------------------------------

pwm0 = PWM(Pin(5))

pwm0.freq(100)

pwm0.duty(100)

print('Flash..')

count = 0;

while True:

    count += 1

    if (count & 0x10) == 0:

        led0.on()

    else: led0.off()

    time.sleep_ms(10)

    adcval = adc.read()

    duty = 100 + adcval // 10

    pwm0.duty(duty)

#------------------------------------------------------------

# END OF FILE : test1.PY

#============================================================

▲ Figure 2.2.2 ADC.read() time cycle

According to the waveform of LED1, we can see that the time of adc.read() is about 240μs.

2. Test conditions

  Since the module's voltage undervoltage point has only two gears, 6V and 9V, when the module is powered by the DG1766 DC voltage source, if the voltage is set to 6V or 9V, the module will alarm. The alarm is displayed by the sound of the motor.

  Set the voltage to 8V ~ 8.5V. If it is above 10V, the module can drive the brushless motor to run normally.

3. The inertia wheel of the unicycle is loose

  During the whole high-speed operation of the inertia wheel of the unicycle, the frame vibrates violently. At high speed, the unicycle cannot maintain balance for a short period of time and produces relatively fast precession rotation.

  After several rounds of testing, loose linearity appeared between the inertia wheel of the car model and the motor.

▲ Figure 1.3.3 The motor inertia wheel has become loose

2. Wheelbarrow Support Wheel

1. The speed is too fast

  The wheelbarrow's support wheel is driven, and the wheelbarrow rotates very fast. This also shows that the use of a brushless motor for driving the support wheel of this wheelbarrow is not suitable.

▲ Figure 1.3.4 Support wheels for driving a wheelbarrow

2. Stall and lost steps

  This type of brushless motor will lose steps when it is stalled by external force.

▲ Figure 1.3.5 The unicycle loses its footing when there is an external force blocking it

3. Small car model rear wheel motor

1. High speed

  The motor of a small car model is driven by the above ESC. The car model rotates very fast, which also shows that the reduction ratio brought by this driving method is not enough.

▲ Figure 2.3.1 Small car model rear wheel motor

2. Output voltage waveform

  The following is one of the voltage waveforms of the three-phase voltage output observed using an oscilloscope.

▲ Figure 1.3.3 Three-phase motor output voltage waveform

4. Bosai motorcycle rear wheel

  The drive module is used to drive the rear wheel of the motorcycle provided by Bosai Company. The rear wheel motor has three-phase control point pressure line and HALL output signal.

  The rear wheel simply vibrates and cannot turn.

▲ Figure 2.4.1 Motorcycle rear wheel provided by Bosai Company

※ Test Conclusion ※

  By testing a three-phase brushless motor ESC, we measure its basic usage. Since the ESC has automatic voltage protection, its power supply needs to be able to avoid 6V and 9V. This way it can work correctly.

  The driver can drive some brushless motors normally. The control signal is similar to the servo control signal. 1ms corresponds to the minimum throttle, and 2ms corresponds to the maximum throttle.