Brushless DC Motor Control with Drives Control June

Brushless DC Motor Control with Drives & Control June 2003 A. Jansen 1 C 868 and CAPCOM 6

Agenda q Basics of a BLDC Motor Ø Topology Ø BLDC Motor with Hall Sensors Ø BLDC Motor with Hardware BEMF-Detection Ø BLDC Motor Sensor less Control q Switching Pattern for Driving a BLDC q How to use the CAPCOM 6 E for a BLDC Ø Introduction CAPCOM 6 E for BLDC purpose Ø CAPCOM 6 E & ADC Drives & Control June 2003 A. Jansen 2

Electrical Motor Types Electric Motor types AC Asynchronous DC Synchronous Induction PMSM Drives & Control June 2003 A. Jansen 3 Synchronous Switched Rel. Stepper

BLDC Basics Drives & Control June 2003 A. Jansen 4

Basics of a BLDC Motor + N U W S U V - q DC Motor with 3 Brushes W V q 3 -Phase Brush-less DC Motor According to theory of DC machine, the motor rotational speed can be written as follows: N = ( Ud - I R ) / (Ke ) While, Drives & Control June 2003 A. Jansen 5 “N” stands for the motor rotational speed “Ud” stands for the DC voltage applied to the motor windings “R” is the pure resistance of the winding while “I” stands for the winding current “Ke” is the magnet coefficient while “ ” stands for the motor magnetic flux From the above formula, there are two methods to change the speed of DC motor: One is to change the DC voltage of the motor windings (Ud), the other one is to change the magnetic flux of the motor ( ). As the BLDC motor has permanent magnet rotor, only the first method can be used in practical application. The principal of generating variable DC voltage is to use PWM for chopping: change the duty cycle of the PWM voltage, proportionally change the DC voltage.

How an Inverter Turns a BLDC (1) Drives & Control June 2003 A. Jansen 6

How an Inverter Turns a BLDC (2) Drives & Control June 2003 A. Jansen 7

How an Inverter Turns a BLDC (3) Drives & Control June 2003 A. Jansen 8

How an Inverter Turns a BLDC (4) Drives & Control June 2003 A. Jansen 9

How an Inverter Turns a BLDC (5) Drives & Control June 2003 A. Jansen 10

How an Inverter Turns a BLDC (6) Drives & Control June 2003 A. Jansen 11

BLDC with Hall Sensors – Switching Pattern q Typical Switching Pattern for a BLDC Ø Hall Sequence depends on motor construction Ø Output pattern levels depends on inverter topology Drives & Control June 2003 A. Jansen 12

BLDC with Hall Sensors Drives & Control June 2003 A. Jansen 13

BLDC with Hall Sensors -- Topology q Typical Circuit Block Diagram Ø Hall Sensors detect the position Ø Over current protection and control via ADC Drives & Control June 2003 A. Jansen 14

Block Diagram CAPCOM 6 E for BLDC Usage Drives & Control June 2003 A. Jansen 15

Usage of CAPCOM 6 E to Control a BLDC (1) q BEMF-Detection/Hall Signals Ø HW-noise filter on CCPOSx inputs (BEMF-signals) Drives & Control June 2003 A. Jansen 16

Usage of CAPCOM 6 E to Control a BLDC (2) q BEMF-Detection/Hall Signals Ø HW-noise filter on CCPOSx inputs (BEMF-signals) Ø automatic reset of T 12 with interrupt Ø actual speed by capture ch 0 Drives & Control June 2003 A. Jansen 17

Usage of CAPCOM 6 E to Control a BLDC (3) q BEMF-Detection/Hall Signals Ø HW-noise filter on CCPOSx inputs (BEMF-signals) Ø automatic reset of T 12 with interrupt Ø actual speed by capture ch 0 Ø phase delay function on ch 1 Drives & Control June 2003 A. Jansen 18

Usage of CAPCOM 6 E to Control a BLDC (4) q BEMF-Detection/Hall Signals Ø HW-noise filter on CCPOSx inputs (BEMF-signals) Ø automatic reset of T 12 with interrupt Ø actual speed by capture ch 0 Ø phase delay function on ch 1 Ø time out function on ch 2 Drives & Control June 2003 A. Jansen 19

Usage of CAPCOM 6 E – Hall Sensor Mode (1) q CCPOSx Inputs Ø for Hallsensor Interface Drives & Control June 2003 A. Jansen 20 q MCMOUTSH / MCMOUTSL Ø SW programmable state machine

Usage of CAPCOM 6 E – Hall Sensor Mode (2) q CCPOSx Inputs Ø edge detection triggers Dead Time Counter Drives & Control June 2003 A. Jansen 21 q MCMOUTSH / MCMOUTSL Ø compare CCPOSx level with programmed value

Usage of CAPCOM 6 E – Hall Sensor Mode (2) q CCPOSx Inputs Drives & Control June 2003 A. Jansen 22 q MCMOUTSH / MCMOUTSL Ø switch to next state on valid edge by hardware

Usage of CAPCOM 6 E – Hall Sensor Mode (3) q CCPOSx Inputs Ø wait on edge Drives & Control June 2003 A. Jansen 23 q MCMOUTSH / MCMOUTSL Ø prepare next state by software

Usage of CAPCOM 6 E – Modulation Control (some Choices) Drives & Control June 2003 A. Jansen 24

Usage of CAPCOM 6 E – Generate the PWM Pattern for BLDC Drives & Control June 2003 A. Jansen 25

Usage of CAPCOM 6 E – Generate the PWM Pattern for BLDC Drives & Control June 2003 A. Jansen 26

Usage of CAPCOM 6 E – Generate the PWM Pattern for BLDC Drives & Control June 2003 A. Jansen 27

Usage of CAPCOM 6 E – Generate the PWM Pattern for BLDC Drives & Control June 2003 A. Jansen 28

Usage of CAPCOM 6 E – Generate the PWM Pattern for BLDC Drives & Control June 2003 A. Jansen 29

Usage of CAPCOM 6 E – Generate the PWM Pattern for BLDC Drives & Control June 2003 A. Jansen 30

Usage of CAPCOM 6 E – Modulation and Synchronization Drives & Control June 2003 A. Jansen 31

Usage of CAPCOM 6 E – Modulation and Synchronization Drives & Control June 2003 A. Jansen 32

Usage of CAPCOM 6 E – Modulation and Synchronization Drives & Control June 2003 A. Jansen 33

Usage of CAPCOM 6 E – Modulation and Synchronization Drives & Control June 2003 A. Jansen 34

Usage of CAPCOM 6 E to Control a BLDC (5) Drives & Control June 2003 A. Jansen 35

Usage of CAPCOM 6 E to Control a BLDC (6) Drives & Control June 2003 A. Jansen 36

Usage of CAPCOM 6 E to Control a BLDC (7) Drives & Control June 2003 A. Jansen 37

Usage of CAPCOM 6 E to Control a BLDC (8) Drives & Control June 2003 A. Jansen 38

BLDC Sensor less Drives & Control June 2003 A. Jansen 39

BLDC in Theory – Back Electro Magnetic Force q Theory Ø UP = (R x i) + (L x di/dt) + e. P Ø where "UP" "R" "i" "L" "di/dt" "e. P" magnet Ø while i = 0 and di/dt = 0: UP = e. P Ø by measuring UP a position detection is possible Drives & Control June 2003 A. Jansen 40 stands for phase voltage stands for winding resistance stands for actual phase current stands for phase inductance stands for changment of phase current over time stands for electromagnetic voltage caused by

BLDC in Reality (1) – BEMF vs. Current q Real BEMF Voltage and Current: Ø shape depends on magnets, motor speed, voltage Drives & Control June 2003 A. Jansen 41

BLDC in Reality (2 a) – BEMF vs. Current q Zoom In: Ø BEMF is only visible at active switching Phase Current BEMF Voltage Drives & Control June 2003 A. Jansen 42

BLDC in Reality (2 b) – BEMF vs. Current q Current Commutation in a Coil Ø Freewheeling diode conducts Phase Current BEMF Voltage Drives & Control June 2003 A. Jansen 43

BLDC in Reality (3) – All Important Signals BEMF Voltage Drives & Control June 2003 A. Jansen 44 Phase Current

BLDC Sensor less with Hardware BEMF-Detection q Typical Circuit Block Diagram Ø Comparators and RC-Filter detect the BEMF zero crossing for position detection Drives & Control June 2003 A. Jansen 45

BLDC Sensor less Using ADC q Typical Circuit Block Diagram Ø Use simple resistor divider and ADC for position detection Drives & Control June 2003 A. Jansen 46

CAPCOM 6 E & ADC q Synchronize ADC on T 13 Ø Ø Drives & Control June 2003 A. Jansen 47 T 13 period match can trigger the ADC equidistant sampling of analog signals exact timing guaranteed by hardware no timing jitter due to software delays

CAPCOM 6 E & ADC q Synchronize T 13 on T 12 Ø T 13 performs delay for stable measurement Ø T 13 period match triggers ADC q Useful for Current Measurement Ø E. g. induction machine Drives & Control June 2003 A. Jansen 48

CAPCOM 6 E & ADC q T 13 PM triggers ADC Ø Delay between T 13 PM and high voltage switching event due to driving circuit q Useful for Voltage or Current Measurement Ø E. g. BEMF detection Ø Sample shortly before power device is switched off (BEMF is noise free) Drives & Control June 2003 A. Jansen 49

CAPCOM 6 E & ADC q T 13 PM triggers ADC Ø Delay between T 13 PM and high voltage switching event due to driving circuit q Useful for Voltage or Current Measurement Ø E. g. Current in DC link path Ø Sample shortly before power device is switched off (current is noise free) Drives & Control June 2003 A. Jansen 50

BLDC Sensor less Using ADC q T 13 used for Ø Modulation Ø ADC trigger q T 12 used for Ø Phase delay q Software (for 60° sector) Drives & Control June 2003 A. Jansen 51 Ø With every T 13 PM the BEMF voltage is sampled and compared to a BEMFwave table Ø When crossing a limit the software generates a CHEevent (1) Ø Speed reference is captured and phase delay for T 12 ch 1 is calculated Ø At T 12 ch 1 the pattern for the next sector is switched (2)

BLDC Sensor less with Current Control q T 13 used for Ø Modulation Ø ADC trigger q T 12 used for Ø Phase delay q Software (for 60° sector) Ø With every T 13 PM the ADC alternatively samples § BEMF voltage § Phase current Ø The current set value can be controlled by adjusting the PWM duty cycle Drives & Control June 2003 A. Jansen 52

BLDC Sensor less Scope Shots Port pin toggles when BEMF is below limit Phase Current Drives & Control June 2003 A. Jansen 53 BEMF Voltage

High Voltage 3 -Phase Brushless DC / Induction Motor Reference Design and Development Kit q Application: Line powered Industrial Drives Ø Power: 750 W Ø Current: max. 5 A Ø AC Input Voltage: 110 to 264 VAC q Features: Drives & Control June 2003 A. Jansen 54 Ø 8 -bit MCU: C 868 with on-chip 8 k. B SRAM, with 8 bit ADC and powerful PWM module Ø Cool. Set: TDA 61831 G instead of a transformer for 12 V supply Ø 6 rugged IGBT Duo. Packs Ø EEPROM: 8 k. B to store program + stand alone boot option Ø Optically Isolated Serial Interface to PC for SW development + boot from PC option Ø Protection: shut down protection for over current and over temperature Ø Extension for alternative MCU like XC 164 or TC 1775 Ø SW environment: Keil Compiler + Debugger or Mini Debugger (free software) Ø Board can be used for current/torque or speed control Ø Supports Hall-Effect sensors or sensor-less control

Low Voltage 3 -Phase Brushless DC / Induction Motor Reference Design and Development Kit q Application: Industrial & Automotive Drives Ø Power: 1. 2 k. W Ø Current: max. 50 A Ø Voltage: 12 - 24 V DC q Features: Ø 8 -bit MCU: C 868 with on-chip 8 k. B SRAM, with 8 bit ADC and powerful PWM module Ø 3 -Phase Bridge Driver: TLE 6280 G Ø 6 Opti. MOSFETs Ø EEPROM: 8 k. B to store program + stand alone boot option Ø RS 232: Interface to PC for SW development + boot from PC option Ø Protection: shut down protection for over current and over temperature Ø Extension for alternative MCU like XC 164 Ø SW environment: Keil Compiler + Debugger or Mini Debugger (free software) Ø Board can be used for current/torque or speed control Ø Supports Hall-Effect sensors or sensor-less control Drives & Control June 2003 A. Jansen 55