TMS320F28026F, TMS320F28027F InstaSPIN™-FOC Software Technical Reference Manual Literature Number: SPRUHP4 August 2013
Contents 1 2 3 4 5 6 TMS320F2802xF InstaSPIN™-FOC Enabled MCUs ................................................................... FAST Estimator Features ..................................................................................................... InstaSPIN™-FOC Solution Features ....................................................................................... InstaSPIN-FOC Block Diagram ..............................................................................................
www.ti.com List of Figures .................................. ............................ Sensored FOC System ................................................................................................... Inverter Using the 3-Shunt Current Sampling Technique ............................................................ Software Execution Clock Tree Provides Flexibility with Real-Time Scheduling.................................. 28027 Memory Map .........................................................
Technical Reference Manual SPRUHP4 – August 2013 TMS320F28026F, TMS320F28027F InstaSPIN™-FOC Software 1 TMS320F2802xF InstaSPIN™-FOC Enabled MCUs TMS320F2802xF are the second family of devices (26F and 27F — 48-pin package) from Texas Instruments that include the FAST™ (Figure 1) estimator and additional motor control functions needed for cascaded speed and torque loops for efficient three-phase field-oriented motor control (FOC).
TMS320F2802xF InstaSPIN™-FOC Enabled MCUs www.ti.com a T a \ a Irated Ir_in a T a \ It_in a Z a Z aW aW Flux Angle Speed EST_run Torque & ^d¡ ]u } Flux, Angle, Speed, Torque Motor Parameters ID Motor Phase Currents Vr_in Vt_in Vbus Motor Phase Voltages Bus Voltage ROM a Rs a Rr a Lsd a Lsq Enable PowerWarp¡ Enable Motor Identification Enable Rs Online Recalibration a \rated a Irated Enable Force Angle Startup Motor Type Figure 1.
FAST Estimator Features 2 FAST Estimator Features • • • • • • • • • • • 3 Unified observer structure which exploits the similarities between all motors that use magnetic flux for energy transduction – Both synchronous (BLDC, SPM, IPM), and asynchronous (ACIM) control are possible – Salient compensation for Interior Permanent Magnet motors: observer tracks rotor flux and angle correctly when Ls-d and Ls-q are provided Unique, high quality motor feedback signals for use in control systems – High-qualit
InstaSPIN-FOC Block Diagram www.ti.
Comparing FAST Estimator to Typical Solutions 5 www.ti.com Comparing FAST Estimator to Typical Solutions Table 1 shows a comparison of the FAST estimator and InstaSPIN-FOC solution to typical software sensors and FOC solutions. Table 1. FAST Estimator Compared to Typical Solutions 8 Topic Typical Software Sensors and FOC Solutions Fast Estimator and InstaSPIN-FOC Solution Electrical Motor Parameters Motor-model based observers heavily dependent on motor parameters.
FAST Provides Sensorless FOC Performance www.ti.com 6 FAST Provides Sensorless FOC Performance 6.1 FAST Estimator Replaces Mechanical Sensor Field-oriented control (FOC) of an electric motor results in superior torque control, lower torque ripple, and in many cases, improved efficiency compared to traditional AC control techniques. For best dynamic response, rotor flux referenced control algorithms are preferred to stator flux referenced techniques.
FAST Provides Sensorless FOC Performance www.ti.com With any technique, the process of producing a stable software sensor is also extremely challenging, as this motor model (observer) is essentially its own control system that needs to be tuned per motor across the range of use. This tuning must be done with a stable forward control loop.
FAST Provides Sensorless FOC Performance www.ti.com • • 6.2 Eliminates or reduces motor parameter variation effects. Automatically designs a stable and functional control system for most motors in under two minutes.
Evaluating FAST and InstaSPIN-FOC Performance www.ti.com C B A C2 B2 A2 R1shunt C1 B1 A1 VDC + - R3shunt R2shunt A1 C phase current window is too small. Sample phases A and B. B1 Sample Here C1 Sample Here A1 B phase current window is too small. Sample phases A and C. B1 C1 Sample Here A1 A phase current window is too small. Sample phases B and C. B1 C1 Figure 4.
Microcontroller Resources www.ti.com InstaSPIN-FOC provides flexibility throughout its design, including its software execution clock tree. Figure 5 illustrates the options available to the designer to manage the real-time scheduling of each of the major software functions. Balancing motor performance with CPU loading is not difficult, shortening system integration time.
Microcontroller Resources www.ti.com Table 2.
Microcontroller Resources www.ti.com 8.1 Memory Allocation and Utilization Figure 6, Figure 7, and Table 4 show the memory map of the 28027, the location in ROM where the InstaSPIN-FOC library is located, and the required allocation of M1 RAM for the library to use. For a general memory map of these devices, see the device-specific data sheet.
Microcontroller Resources www.ti.com Table 4. 2802xF Allocated Memory for InstaSPIN-FOC Library Features 2802xF Maximum Number of Motors that can be controlled 1 FAST Version 1.7 ROM Library [size, hex, words] 2000 ROM Library Start [address, hex] 3F C000 Library Required RAM [size, hex, words] 200 Library Start RAM [address, hex] 600 Figure 7 highlights the pieces of ROM EXE-only memory used by the libraries. EXE-only is execute only memory where read access is not possible.
Microcontroller Resources www.ti.com 8.2 Pin Utilization Flexibility in the design of InstaSPIN-FOC allows for multiple motors to be supported. Table 6 lists the minimum and maximum pins used per motor. Note that a F2802xF microcontroller provides (8) ePWM outputs with the 48-pin package. Table 6.
www.ti.com Appendix A Definition of Terms and Acronyms ACIM — Alternating current induction motor. CCStudio — Code Composer Studio. FAST — Unified observer structure which exploits the similarities between all motors that use magnetic flux for energy transduction, automatically identifying required motor parameters and providing the following motor feedback signals: • High-quality Flux signal for stable flux monitoring and field weakening.
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