UM0708 User manual - st.com

1 June 2009 Doc ID 15773 Rev 11/85UM0708 User manualSTM8 Sxxxthree-phase BLDC motor control software library user manual describes the brushless direct current motor (BLDC) scalar software library, a scalar control firmware library for 3-phase permanent-magnet (PM) motors developed for the STM8 Sxxx STM8 Sxxx 8-bit microcontrollers come with a set of peripherals that makes them suitable for performing both PM and AC induction motor scalar present document describes the STM8 Sxxx software library developed to control trapezoidal driven PM motors in both open loop and speed control mode. These motors may be equipped with three Hall sensors or may be sensorless.

2 The control of an AC induction motor equipped with tachogenerator is described in the UM0712 user BLDC motor software library is made of several C modules, and is fitted out with STVD workspace. It is used to quickly evaluate both the MCU and the available tools. In addition, when used together with the STM8/128-MCKIT motor control starter kit and a PM motor , a motor can be made to run in a very short time. The BLDC library also eliminates the need for time-consuming development of low level drive and speed regulation algorithms by providing ready-to-use functions that let the user concentrate on the application layer. Moreover, it is possible to get rid of any speed sensor thanks to the sensorless algorithm for rotor position reconstruction based on BEMF prerequisite for using this library is basic knowledge of C programming, PM motor drives and power inverter hardware.

3 In-depth know-how of STM8 Sxxx functions is only required for customizing existing modules and for adding new ones for a complete application ContentsUM07082/85 Doc ID 15773 Rev 1 Contents1 Features .. line STM8S features .. line STM8S features .. software library features (CPU running at 16 MHz) .. tools .. tools .. documents .. 132 Introduction to STM8S BLDC control .. to BLDC theory .. synchronization .. speed regulation .. voltage modulation .. speed measurement .. delay and demagnetization time .. of BEMF zero crossings .. during PWM signal on-time .. during PWM signal off-time.

4 BEMF sampling method .. demagnetization .. the delay coefficient accordingly a specified curve .. strategy in sensorless mode .. phase .. phase .. brake .. 263 Running the demonstration program .. interface structure .. conventions .. message .. menus .. 28UM0708 ContentsDoc ID 15773 Rev 13/85 menu - target and measured rotor speed .. interface sub-menus .. overview .. rising and falling delays .. the current reference and duty cycle .. the speed regulator .. the demagnetization time .. the measured current , DC bus voltage and heatsink temperature.

5 Options: fast demagnetization, toggle mode, and auto-delay messages .. 354 Getting started with the STM8S BLDC firmware .. state machine .. of the states .. of the state machine operation .. architecture .. registers .. I/Os .. structure .. control .. the advanced control timer peripheral (TIM1) .. the ADC .. sensor management .. brake .. level control .. scalar control .. timers .. BLDC virtual timers .. timers related functions .. 545 Designing an application using the BLDC software library .. the BLDC software library parameter file .. configuration file ( ).

6 motor parameters ( ) .. drive control parameters ( ) .. sensor parameters ( ) .. 63 ContentsUM07084/85 Doc ID 15773 Rev stage parameters ( ) .. stage parameters ( ) .. clock definition ( ) .. specific BLDC drive parameters ( ) .. pins definition parameters ( ) .. parameter microcontroller interfaces ( ) .. up the system when using a brake resistor .. 736 Library functions .. description conventions .. description .. level MC modules .. level MC modules .. 81 Appendix A Additional information.. configuration .. control related CPU load .. motor control builder GUI.

7 83 Revision history .. 84UM0708 List of tablesDoc ID 15773 Rev 15/85 List of tablesTable and RAM requirements .. 12 Table demagnetization table.. 23 Table conventions .. 28 Table registers .. 40 Table I/Os .. 40 Table Drive structure .. 41 Table channel output configurations .. 43 Table enable bit register configuration .. 43 Table sensor commutation table for Shinano motor .. 50 Table virtual timers .. 53 Table pins description .. 62 Table filters .. 70 Table sensor filters .. 73 Table .. 83 Table revision history .. 84 List of figuresUM07086/85 Doc ID 15773 Rev 1 List of figuresFigure motor control sequence (first three steps).

8 14 Figure motor BEMF signal .. 14 Figure mode .. 16 Figure time measurement sensorless drive.. 17 Figure and phase current synchronization .. 17 Figure time .. 18 Figure during the on-time .. 19 Figure during off-time .. 20 Figure BEMF sampling method implementation .. 20 Figure phases bridge and stator windings .. 21 Figure between step 1 and step 2 .. 22 Figure between step 2 and step 3 .. 23 Figure delay computation accordingly a specified curve .. 24 Figure phase .. 25 Figure sequence .. 26 Figure structure and navigation .. 27 Figure drive welcome message.. 28 Figure menu .. 29 Figure menu - Target speed and measured speed.

9 29 Figure the target speed .. 29 Figure interface sub-menu .. 30 Figure selected for edition .. 30 Figure rising and falling delays .. 31 Figure variables .. 31 Figure the speed regulator proportional and integral terms .. 32 Figure the speed regulator tuning derivative term: demagnetization time .. 32 Figure measurement .. 33 Figure bus voltage and heat sink measurements .. 33 Figure fast demagnetization and toggle mode options .. 34 Figure option .. 34 Figure message shown in case of undervoltage.. 36 Figure motor control state machine.. 38 Figure architecture: high-level/low-level interface.

10 39 Figure BLDC library organization .. 39 Figure output control signals .. 43 Figure regulation/limitation .. 44 Figure between TIM1 and ADC .. 45 Figure and asynchronous ADC conversion .. 45 Figure conversion .. 46 Figure conversions .. 47 Figure peripheral used for Hall sensor management .. 47 Figure time measurement for sensored drive .. 48 Figure motor Hall sensor configuration- 120 , clockwise direction .. 49 Figure motor Hall sensor configuration- 120 , counter-clockwise direction .. 49 Figure sensor configuration- 60 , clockwise direction .. 50 Figure sensor configuration- 60 , counter-clockwise direction.