Control algorithms

Table of Contents

• Introduction
• Features Supported
• Field Weakening Control
• Maximum Torque Per Ampere
• Stator Voltage Frequency Generator
• Benchmark Results
• API

Introduction

This section goes over a collection of control algorithms and techniques used in motors such as PMSM and BLDC. The library source code can be found in motor_control_sdk/source/rtlibs/control.

Features Supported

Supported algorithms:

• Field weakening control (FWC)
• Maximum torque per ampere (MTPA)
• Stator voltage frequency generator (VS_FREQ)

Field Weakening Control

Field weakening control (FWC) is a control methodology used in iPMSM motors to expand operating limits and enable higher than rated speed while allowing optimal control across speed and voltage range.

Maximum Torque Per Ampere

Maximum Torque Per Ampere (MTPA) technique is used for iPMSM to optimize torque generation in the constant torque region. As iPMSM motor's total torque has a non-linear relationship with respect to the rotor angle.

Stator Voltage Frequency Generator

Stator Voltage Frequency Generator (VS_FREQ) can be used in scalar volts/hertz motor control scheme. It generates an output command voltage based on the specified volts/hertz profile and the inputted command frequency.

Benchmark Results

A benchmark on Arm® Cortex®-R5F core has been conducted to observe the following results when running controller arithmetic:

Functions	CPU Cycles
Single-shunt DC-Link
DCLINK_SS_runCurrentReconstruction	14
DCLINK_SS_runFastCurrentReconstruction	5
DCLINK_SS_runPWMCompensation	201
DCLINK_SS_runFastPWMCompensation	107
Field weakening control
FWC_computeCurrentAngle	35
Maximum torque per ampere
MTPA_computeCurrentReference	101
MTPA_computeCurrentAngle	85
Stator voltage frequency generator
VS_FREQ_run	29

• Ran with TI Clang Compiler v3.2.0.LTS, with -Os flag, obtained the average result from 600 consecutive readings of running the controller with DPL CycleCountP minus the overhead, simulating a control loop scenario.
• Actual result may vary depending on provided datasets and memory configuration. For Arm Cortex-R5F, it is recommended for users to map control loops to TCM for the best performance.

API

APIs for Control algorithms

Note

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