eBike Sensorless Motor Control
Alex Lollio, Global Rotation Engineer

Automotive Products Business Unit
Provence Design Ce...
e-Bike Overview
Market Info:
• $8.4 billion in 2013*
• 90% of e-Bike sales in China*

48V Lit Battery

General Specificati...
BLCD Motor Working Principle: 2 Pole

COMPANY CONFIDENTIAL
IR Controller for e-Bike: IR3230
Main Features:
• Brushless DC Motor Sensor Decoder & HVIC MOSFET Driver
• Charge pump ope...
Project Goal: Sensorless Implementation
Costumer Request:
• Sensorless driving strategy: reducing costs, simplify motor as...
+Vbat

Cpum
p

Cd

Pmp

Vcc

Tp

CTN

Gnd_p

Shunt

Charge pump

Ground

Shtp

Rs hunt

Shtm
Vss

+5v

Power _m f et
os

R...
What is Back Electromagnetic Force?
A

GND

Example: Trapezoidal Motor Driving
Faraday Law:
The induced Electromagnetic Fo...
Back EMF when duty cycle is 100%
Trapezoidal Driving
6 Step Sequence
A

A

C

Step 1

B C

Step 2

THIS GRAPH SHOWS THE VO...
Back EMF @Duty=20% (low side modulation)
Trapezoidal Driving
6 Step Sequence

C

Step 1

High Side ON

A

A

B C

Step 2

...
BEMF in Trapezoidal Motor Driving
Z 0 0 Z 1 1

PH1-A

PH2-B
VDD
VDD/2

1 1 Z 0 0
PH3-C

T/2

Z

0 Z 1 1 Z 0

T
Sens3

Sens...
Basic Idea: Circuital Implementation
PICF1937

IR3230

RE0
RE1
RE2

VSUP
VREF

MOTOR
WINDINGS

POWER
MOSFET

RA3

SNS1
SNS...
Basic Idea: Algorithm working principle
The Back EMF tracking Algorithm works like a PLL: adjusting the
commutation period...
Demoboard Image
Connector to ICD3
BEMF
programmer
Voltage
Divider

PHA

IR3230
PWM
Trimmer

PHB
PHC

BEMF Voltage Divider ...
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eBike Sensorless Motor Control

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eBike Sensorless Motor Control

  1. 1. eBike Sensorless Motor Control Alex Lollio, Global Rotation Engineer Automotive Products Business Unit Provence Design Centre, France May, 2013 - Jul, 2013 Project Manager : Andre Mourrier Program Mentor : Massimo Grasso COMPANY CONFIDENTIAL 1
  2. 2. e-Bike Overview Market Info: • $8.4 billion in 2013* • 90% of e-Bike sales in China* 48V Lit Battery General Specifications: • Battery 40-48V (10AH) • Power 150W - 500W • Input Current 10-15ARMS • BLDC Motor Control Board BLDC Motor IR Interests: • 6 Power MOSFETS (IRFB3607) • IC Controller and Gate Driver (IR3230) *http://www.navigantresearch.com/research/electric-bicycles COMPANY CONFIDENTIAL
  3. 3. BLCD Motor Working Principle: 2 Pole COMPANY CONFIDENTIAL
  4. 4. IR Controller for e-Bike: IR3230 Main Features: • Brushless DC Motor Sensor Decoder & HVIC MOSFET Driver • Charge pump operation (No bootstrap capacitor) • Up to 30Khz PWM switching capability (on the low switches) • Programmable over current and over temperature protections +5V Yellow = sensor3 Green = sensor2 Blue = sensor1 IR3230 GND GND +5V Battery power supply Battery power supply + COMPANY CONFIDENTIAL
  5. 5. Project Goal: Sensorless Implementation Costumer Request: • Sensorless driving strategy: reducing costs, simplify motor assembly and reducing failure (most failure = Hall sensors) Electronic Board Sensorless Cost Saving BLDC Motor Power FETs: 0.2$ x 6 ≈ 1.2$ Discrete Components ≈ 0.5$ Microcontroller ≈ 0.6$ Hall Sensors: 0.4$ x 3 ≈ 1.2$ Sensors(0.15$)+Assembly(0.15$)+Cabling(0.1$) Goal of the Project: • Adapt IR3230 Controller & HVIC driver for a Sensorless implementation COMPANY CONFIDENTIAL
  6. 6. +Vbat Cpum p Cd Pmp Vcc Tp CTN Gnd_p Shunt Charge pump Ground Shtp Rs hunt Shtm Vss +5v Power _m f et os Rdig_in Diagnostic and Reset Flt Rdig_in1 Flt_rst D gi t al i I/O Rdig_in2 Gls1 Ho2 Ghs2 Sk_ph2 Lo2 Gls2 Ho3 Ghs3 Sk_ph3 Gls3 Vbattery Lo1 Lo3 SOIC28 5V Power Supply Gnd Sk_ph1 Vs3 IR3230 IR3230 Vs1 Vs2 5.6V Ghs1 M1 Ph1 Ph1 Ph2 Ph2 Ph3 +5v Ph3 Gnd Ho1 BLDC Motor Power Mosfet Out_Supply Gnd + + TºC Measurement IR3230 Typical Schematic Gnd_p 120/60 +5v Sens1 Sens2 Sens3 Gnd Rdig_in3 Rev /Fwd Rdig_in4 Mot/Regen Rdig_in5 Pwm Order input and Selection En Gnd Rdig_in6 Gndpwr +5v Sens1 Sens2 Sens3 Sensors interface Gnd Basic Idea: replacing the Hall Sensor with a Micro which senses the generated BEMF COMPANY CONFIDENTIAL
  7. 7. What is Back Electromagnetic Force? A GND Example: Trapezoidal Motor Driving Faraday Law: The induced Electromagnetic Force (EMF) is the voltage produced by changing magnetic flux into the windings C B C Floating VCC Floating phase, C, can be used to measure the Back EMF generated by the turning rotor. Generated Back EMF is proportional to angular rotation speed A + - B COMPANY CONFIDENTIAL
  8. 8. Back EMF when duty cycle is 100% Trapezoidal Driving 6 Step Sequence A A C Step 1 B C Step 2 THIS GRAPH SHOWS THE VOLTAGE OF NODE PHA High Side ON B PHA VDD BEMF crosses VDD/2 in the middle of the switching period A A VDD/2 C Step 3 BC A Step 4 High Side ON Switching Period B A Low Side ON Inductive transient C Step 5 B C B Step 6 PHA 1 Step 2 Z 3 Inductive transient 0 4 0 5 Z 6 COMPANY CONFIDENTIAL 1 1
  9. 9. Back EMF @Duty=20% (low side modulation) Trapezoidal Driving 6 Step Sequence C Step 1 High Side ON A A B C Step 2 THIS GRAPH SHOWS THE VOLTAGE OF NODE PHA High Side ON Switching Period B PHA A A VDD/2 C Step 3 BC A Step 4 B A Low Side PWM C Step 5 B C B Step 6 PHA Step 1 2 Z 3 PWM 4 PWM 5 Z 6 COMPANY CONFIDENTIAL 1 1
  10. 10. BEMF in Trapezoidal Motor Driving Z 0 0 Z 1 1 PH1-A PH2-B VDD VDD/2 1 1 Z 0 0 PH3-C T/2 Z 0 Z 1 1 Z 0 T Sens3 Sens1 6 STEPS 1 0 0 0 1 0 0 0 1 1 1 0 Sens2 1 1 1 1 0 0 1 2 3 4 5 6 Algorithm Strategy: VDD/2 crossing point in the middle of the switching cycle COMPANY CONFIDENTIAL
  11. 11. Basic Idea: Circuital Implementation PICF1937 IR3230 RE0 RE1 RE2 VSUP VREF MOTOR WINDINGS POWER MOSFET RA3 SNS1 SNS2 SNS3 A RD5 PWM C B RB1 RA1 RB3 • Microcontroller compares the BEMF voltages to the reference voltage VREF • When BEMF<VREF the internal comparator generates an interrupt (let’s call this event “zero-cross”) BEMF Voltage TS TS/2 zero-cross VREF time COMPANY CONFIDENTIAL
  12. 12. Basic Idea: Algorithm working principle The Back EMF tracking Algorithm works like a PLL: adjusting the commutation period in order to keep zero-cross in the middle TIMER1 Commutation periods Timer1 overflow FFFFh Late zero-cross Perfe o-c t ze r c r o ss error Perfe -N/2 Half commutation preset r o ss ero-c ct z -N’/2 -N error -N’ = -(N+error) 0000h Time Full commutation preset COMPANY CONFIDENTIAL
  13. 13. Demoboard Image Connector to ICD3 BEMF programmer Voltage Divider PHA IR3230 PWM Trimmer PHB PHC BEMF Voltage Divider are tested for input supply voltage into the range 12-48V COMPANY CONFIDENTIAL

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