Datasheet TMC4671 (TRINAMIC) - 8

link to page 8 TMC4671 Datasheet • IC Version V1.00 | Document Revision V1.06 • 2019-Feb-06 8 / 159
3 FOC Basics
This section gives a short introduction into some basics of Field Oriented Control (FOC) of electric motors.
3.1 Why FOC?
The Field Oriented Control (FOC), alternatively named Vector Control (VC), is a method for the most energy-efficient way of turning an electric motor.
3.2 What is FOC?
The Field Oriented Control was independently developed by K. Hasse, TU Darmstadt, 1968, and by Felix Blaschke, TU Braunschweig, 1973. The FOC is a current regulation scheme for electro motors that takes the orientation of the magnetic field and the position of the rotor of the motor into account, regulating the strength in such way that the motor gives that amount of torque that is requested as target torque. The FOC maximizes active power and minimizes idle power - that finally results in power dissipation - by intelligent closed-loop control illustrated by figure 1. Figure 1: Illustration of the FOC basic principle by cartoon: Maximize active power and minimize idle power and power dissipation by intelligent closed-loop control.
3.3 Why FOC as pure Hardware Solution?
The initial setup of the FOC is usually very time consuming and complex, although source code is freely available for various processors. This is because the FOC has many degrees of freedom that all need to fit together in a chain in order to work. The hardware FOC as an existing standard building block drastically reduces the effort in system setup. With that off the shelf building block, the starting point of FOC is the setup of the parameters for the FOC. Setting up and implement the FOC itself and building and programming required interface blocks is no longer necessary. The real parallel processing of hardware blocks de-couples the higher lever application software from high speed real-time tasks and simplifies the development of application software. With the TMC4671, the user is free to use its qualified CPU together with its qualified tool chain, freeing the user from fighting with processer-specific challenges concerning interrupt handling and direct memory access. There is no need for a dedicated tool chain to access the TMC4671 registers and to operate it - just SPI (or UART) communication needs to be enabled for any given CPU. The integration of the FOC as a SoC (System-on-Chip) drastically reduces the number of required compo- nents and reduces the required PCB space. This is in contrast to classical FOC servos formed by motor ©2019 TRINAMIC Motion Control GmbH & Co. KG, Hamburg, Germany Terms of delivery and rights to technical change reserved. Download newest version at www.trinamic.com Document Outline 1 Order Codes 2 Functional Summary 3 FOC Basics 3.1 Why FOC? 3.2 What is FOC? 3.3 Why FOC as pure Hardware Solution? 3.4 How does FOC work? 3.5 What is Required for FOC? 3.5.1 Coordinate Transformations - Clarke, Park, iClarke, iPark 3.5.2 Measurement of Stator Coil Currents 3.5.3 Stator Coil Currents I_U, I_V, I_W and Association to Terminal Voltages U_U, U_V, U_W 3.5.4 Measurement of Rotor Angle 3.5.5 Measured Rotor Angle vs. Magnetic Axis of Rotor vs. Magnetic Axis of Stator 3.5.6 Knowledge of Relevant Motor Parameters and Position Sensor (Encoder) Parameters 3.5.7 Proportional Integral (PI) Controllers for Closed Loop Current Control 3.5.8 Pulse Width Modulation (PWM) and Space Vector Pulse Width Modulation (SVPWM) 3.5.9 Orientations, Models of Motors, and Coordinate Transformations 4 Functional Description 4.1 Functional Blocks 4.2 Communication Interfaces 4.2.1 SPI Slave User Interface 4.2.2 TRINAMIC Real-Time Monitoring Interface (SPI Master) 4.2.3 UART Interface 4.2.4 Step/Direction Interface 4.2.5 Single Pin Interface 4.3 Numerical Representation, Electrical Angle, Mechanical Angle, and Pole Pairs 4.3.1 Numerical Representation 4.3.2 N_POLE_PAIRS, PHI_E, PHI_M 4.3.3 Numerical Representation of Angles PHI 4.4 ADC Engine 4.4.1 ADC Group A and ADC Group B 4.4.2 Internal Delta Sigma ADCs 4.4.3 External Delta Sigma ADCs 4.5 Delta Sigma Configuration and Timing Configuration 4.5.1 Internal Delta Sigma Modulators - Mapping of V_RAW to ADC_RAW 4.5.2 External Delta Sigma Modulator Interface 4.5.3 ADC Configuration - MDAC 4.6 Analog Signal Conditioning 4.6.1 FOC3 - Stator Coil Currents I_U, I_V, I_W and Association to Terminal Voltages U_U, U_V, U_W 4.6.2 Stator Coil Currents I_X, I_Y and Association to Terminal Voltages U_X, U_Y 4.6.3 ADC Selector & ADC Scaler w/ Offset Correction 4.7 Encoder Engine 4.7.1 Open-Loop Encoder 4.7.2 Incremental ABN Encoder 4.7.3 Secondary Incremental ABN Encoder 4.7.4 Digital Hall Sensor Interface with optional Interim Position Interpolation 4.7.5 Digital Hall Sensor - Interim Position Interpolation 4.7.6 Digital Hall Sensors - Masking and Filtering 4.7.7 Digital Hall Sensors together with Incremental Encoder 4.7.8 Analog Hall and Analog Encoder Interface (SinCos of 0° 90° or 0° 120° 240°) 4.7.9 Analog Position Decoder (SinCos of 0°90° or 0°120°240°) 4.7.10 Encoder Initialization Support 4.7.11 Velocity Measurement 4.7.12 Reference Switches 4.8 FOC23 Engine 4.8.1 PI Controllers 4.8.2 PI Controller Calculations - Classic Structure 4.8.3 PI Controller Calculations - Advanced Structure 4.8.4 PI Controller - Clipping 4.8.5 PI Flux & PI Torque Controller 4.8.6 PI Velocity Controller 4.8.7 P Position Controller 4.8.8 Inner FOC Control Loop - Flux & Torque 4.8.9 FOC Transformations and PI(D) for control of Flux & Torque 4.8.10 Motion Modes 4.8.11 Brake Chopper 4.9 Filtering and Feed-Forward Control 4.9.1 Biquad Filters 4.9.2 Standard Velocity Filter 4.9.3 Feed-Forward Control Structure 4.10 PWM Engine 4.10.1 PWM Polarities 4.10.2 PWM Frequency 4.10.3 PWM Resolution 4.10.4 PWM Modes 4.10.5 Break-Before-Make (BBM) 4.10.6 Space Vector PWM (SVPWM) 5 Safety Functions 5.1 Watchdog 6 Register Map 6.1 Register Map Overview 6.2 Register Map Full 7 Pinning 8 TMC4671 Pin Table 9 Electrical Characteristics 9.1 Absolute Maximum Ratings 9.2 Electrical Characteristics 9.2.1 Operational Range 9.2.2 DC Characteristics 10 Sample Circuits 10.1 Supply Pins 10.2 Clock and Reset Circuitry 10.3 Digital Encoder, Hall Sensor Interface and Reference Switches 10.4 Analog Frontend 10.5 Phase Current Measurement 10.6 Power Stage Interface 11 Setup Guidelines 12 Package Dimensions 13 Supplemental Directives 13.1 Producer Information 13.2 Copyright 13.3 Trademark Designations and Symbols 13.4 Target User 13.5 Disclaimer: Life Support Systems 13.6 Disclaimer: Intended Use 13.7 Collateral Documents & Tools 14 Errata 15 Figures Index 16 Tables Index 17 Revision History 17.1 IC Revision 17.2 Document Revision