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Industrial motor c ontrol part 2 not sure if got use or not freescale

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Industrial motor c ontrol part 2 not sure if got use or not freescale

  1. 1. July 2009Industrial Motor Control Part 2Introduction to ACIM and PMSM Motor ControlJeff WilsonIndustrial Segment Marketer, Americas TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009.
  2. 2. Agenda► Introduction to ACIM and PMSM motors • Asynchronous vs. synchronous • AC induction motors and control techniques • Permanent magnet motors and control techniques  PMSM  BLDC► Control and drive system overview► Field oriented control (FOC) principles and Freescale motor control libraries► Sensorless FOC control of a PMSM demonstration and solution overview TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 2
  3. 3. Many Different Motor Types … DC motor Brushless DC motor Stepper motor (half step) Stepper motor (full step) AC induction motor Permanent magnet Switched reluctance motor synchronous motor (PMSM) TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 3
  4. 4. Asynchronous vs. Synchronous► 3-phase winding on the stator► Sinusoidal flux distribution in air gap► Different rotor construction ω  ACIM (Asynchronous) – Squirrel cage or windings – No permanent magnets  Synchronous – Surface or interior permanent magnets – High efficiency (no rotor losses)► Asynchronous means that the mechanical speed of the rotor is generally different from the speed of the revolving magnetic field► Synchronous motors rotate at the same frequency as the revolving magnetic field TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 4
  5. 5. AC Induction Motor► Invented over a century ago by Nikola Tesla► No permanent magnets (the rotor most often consists of a squirrel cage structure)► Think of it as a rotating transformer where the stator is the primary, and the rotor is the secondary► Rotor current is “induced” from stator The rotor does not quite keep Notice the rotor slip up with the current rotating magnetic field of the stator. TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 5
  6. 6. Speed-Torque Performance of Induction Motors TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 6
  7. 7. AC Induction Motor Control Methods► V/Hz Phase Drive: The control algorithm keeps a Voltage Base Point constant magnetizing current (flux) in the 100% motor by varying the stator voltage with frequency. Often implemented with a “slip Boost Voltage controller” (DRM 20 & 21) Boost Frequency Base Freq. Freq.► Field Oriented Control: Transforms voltage, current, and magnetizing flux values to space- vectors and controls the components of those vectors independently (DRM102)► DaveWilson “Great Debate” Article: Slip Control vs. Field Oriented Control TM Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 7
  8. 8. Permanent Magnet AC Motor► A PMSM motor rotates because of the Torque establishment (no-load condition) magnetic attraction between the rotor and stator poles.► When the rotor poles are facing stator poles of the opposite polarity, a strong magnetic attraction is set up between them.► The mutual attraction locks the rotor and stator poles together, and the rotor is literally yanked into step with the revolving stator magnetic field. Torque establishment (load condition)► At no-load conditions, rotor poles are directly opposite the stator poles and their axes coincide.► At load conditions the rotor poles lag behind the stator poles, but the rotor continues to turn at synchronous speed; the mechanical angle (a) between the poles increases progressively as we increase the load. TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 8
  9. 9. Trapezoidal vs. Sinusoidal PM Machine► “Synchronous” in PMSM implies the motor is “sinusoidal”► “Brushless DC” in BLDC implies the motor is “trapezoidal” • Flux distribution characteristics have differing waveforms (sinusoidal vs. trapazoidal) • Field-oriented control vs. “six-step” control • Both methods require rotor position information • BLDC motor control • At any instant, two of the three stator phases are excited • Unexcited phase used as sensor (back emf) • Synchronous motor • All three phases persistently excited (continuous) • Sensorless algorithm becomes complicated TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 9
  10. 10. High Voltage Inverter-based ACIM and PMSM Drive System 110V Converter Motor Drive Inverter or 220V Filter Capacitor Freescale Dave’s Control Center 230V or Fault Signals 460V Buffered Gate Drivers Micro Logic Level PWMs PWMs or DSP Communications Hot Ground! Isolation TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 10
  11. 11. Freescale Motor Control Libraries► Overview • Over 35 functions available covering basic functions (including sin/cos processing), transformations, controllers, modulation techniques and resolver (position sensing) operations • Theory and performance of software modules summarized in library documentation► Specifics • Written in assembly language with C-callable interface • Intended for use in small data memory model projects • Interfaces to algorithms combined into a single public interface include file (mclib.h) • Matlab models available and used for functional testing TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 11
  12. 12. Motor Variables in Vector Representation The “q” axis is the axis of motor torque along The “d” axis refers which the stator field to the “direct” axis must be developed Axis of phase b of the rotor flux +a -c -b N Rotation Axis of phase a +b S +c Rotor made from -a permanent magnets Stator windings Axis of phase c TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 12
  13. 13. Transformation Functions - MCLIB ► Features Execution Function Code Size • Written using CodeWarrior intrinsic functions. Clocks • Documentation describes transformation ClarkTrfm 14 61 theory and implemented equations. ClarkTrfmInv 16 73 • Correct evaluation is guaranteed when ParkTrfm 17 91 saturation flag is set prior to these function ParkTrfmInv 17 92 calls. Inverse Park Inv. Clark Transform Clark Transform Park Transform Transform & SVM techniques θField θField Phase A α d d α Phase A Process Control 3-Phase Stationary Rotating Space Phase B Phase B Phase C to β to q q to β Vector 2-Phase Rotating Stationary Modulation Phase C 3-Phase 3-Phase 2-Phase 2-Phase 3-Phase System System System System System AC DC AC Stationary Reference Frame Rotating Reference Frame Stationary Reference Frame TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 13
  14. 14. Sensorless FOC of PMSM Demonstration TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 14
  15. 15. Sensorless FOC System Block Diagram ~ Line Speed Q-Current Control Voltage Ramp Torque = controlωreq + + PI Inverse Space Udcbus PI Park Vector Controller Controller Transformation Modulation - - uα Inverter uq α,β D-Current Control DC-Bus PWM Ripple Flux u β elimination a,b,c ud d,q Field + PI Control Controller - iα ia α,β a,b,c ib d,q iβ α,β ic θest Park Clarke ωest Tracking Back-EMF Transformation Transformation Observer Observer Freescale Dave’s Control Center 3-Phase PMSM TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 15
  16. 16. Application – Timing► Application based on MC56F8025► Pulse width modulation running at 20 kHz with dead-time insertion Algorithm Performance► FOC current loop running at 10 kHz (100 μsec) FOC current loop takes .55 usec to execute (loop running at 100► Speed control loop running at 1 kHz usec) (1 msec)► Field weakening implemented Speed control loop takes 17 usec► Freescale DSC software library (loop running at 1 msec) • GFLIB (general functions) • GDFLIB (digital filtering) • MCLIB (motor control) • ACLIB (advanced control - sensorless) TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 16
  17. 17. DC Bus Voltage Measurement  Feedback signals are proportional to bus voltage.  Bus voltage is scaled down by a voltage divider.  Values are chosen such that a 400-volt maximum bus voltage corresponds to 3.24 volts at output V_sense_DCB. TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 17
  18. 18. Phase Current Measurements  Shunt resistors measure voltage drop  Two channels sampled simultaneously with 12-bit resolution  Software calculation to obtain values for all 3 phase currents (Kirchhoff’s current law) Q1 Q3 Q5 SK B04 N60 SK B04 N60 SK B04 N60 Ga te _AT Ga te _BT Ga te _CT Ph ase_A Ph ase_B Ph ase_C ISA ISB ISC Q2 Q4 Q6 SK B04 N60 SK B04 N60 SK B04 N60 Ga te _AB Ga te _BB Ga te _CB So urce _AB So urce _BB So urce _CB I_sense_ A1 sense R1 I_sense_ B1 sense R2 I_sense_ C1 sense R3 0.1 1 % 0.1 1 % 0.1 1 % I_sense_ A2 sense I_sense_ B2 sense I_sense_ C2 sense UI_S _A UI_S _B UI_S _C TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 18
  19. 19. Classifications of Sensorless Methods for PM Motors► Back EMF observer  Proper motor parameters, voltage and current required  Challenges at zero and low speed estimation – Measured current low, distortion caused by inverter irregularities – Parameter deviation becomes significant with lowering speed► Utilization of magnetic saliency  Difference in Ld-Lq  Rotor position detected by tracking magnetic saliency  Carrier signal superimposed to main voltage excitation TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 19
  20. 20. Open Loop Start Up- Starting procedure differs from V-axis FG-W Integ theta* washer - No need to operate at low speed Iq* (>300[rpm]) FG-I Current Control - High start-up torque required to speed up Id* FOC a loaded drum MTPA- Motor accelerated in “open loop” means there is no measured position feedback- FG-I and FG-W carefully chosen in order to assure a safe starting with minimum oscillation up to the maximum torque- FG-I – Current function generator- FG-W – Velocity function generator- MTPA – Maximum torque per amp TM Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 20
  21. 21. Model-based Estimator - Extended BEMF Observer-Model-based algorithm - Based on extended BEMF observer - Position and speed extraction by angle tracking observer - Algorithm used over wash cycle operation Merge Alignment Open Sensorless Speed Close - Operation speed range starts reliably Loop Loop from ~300 [rpm] TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 21
  22. 22. Summary► Introduced ACIM and PMSM motors • Asynchronous vs. synchronous differentiators • AC induction motors and control techniques • Permanent magnet motors and control techniques► Outlined motor control and drive system architecture► Discussed field oriented control (FOC) principles and Freescale’s motor control libraries► Demonstrated and reviewed a Freescale DSC-based sensorless FOC control PMSM for a washer application TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 22
  23. 23. Q&A► Thank you for attending this presentation. We’ll now take a few moments for the audience’s questions, and then we’ll begin the question and answer session. TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 23
  24. 24. Related Session ResourcesSessionsSession ID Title AZ116 Industrial Motor Control Roadmap (Part 1) AZ141 FreeMASTER and Quick Start OverviewDemos Meet the FSL ExpertsPedestal ID Demo Title Title Time Location PMSM Sensorless FOC Demo PMSM Dishwasher Pump Demo PMSM for a Top Loading Washer TM Freescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 24
  25. 25. For Further Reference► DRM020: 3-Phase AC Induction Motor Drive with Tachogenerator Using MC68HC908MR32► DRM021: 3-Phase ACIM Volt per Hertz Control Using 56F80x► DRM092: 3-Phase AC Induction Vector Control Drive with Single Shunt Current Sensing► DRM102: PMSM Vector Control with Single Shunt Current Sensing Using MC56F8013/23► Dave Wilson “Great Debate” Article: http://www.industrial- embedded.com/ TMFreescale™ and the Freescale logo are trademarks of Freescale Semiconductor, Inc. All other product orservice names are the property of their respective owners. © Freescale Semiconductor, Inc. 2009. 25
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