BLDC Motor Controller IC with Curve Transformer and Polar FOC

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Solution Overview

Problem

Conventional BLDC motors face challenges in efficiently controlling motor speed, torque, and power due to limitations in rotor position sensing and closed-loop control systems, particularly with Hall effect sensors.

Innovation Solution

A motor controller IC package that utilizes a curve transformer for controlling motor speed, torque, and power, incorporating linear interpolation and polar Field-Oriented Control (FOC) to enhance precision and efficiency in motor control, along with a phase-locked loop scheme for improved accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If Hall effect sensors are mounted on windings for rotor position sensing, then rotor position can be detected, but measurement precision and control accuracy are limited

Engineering Contradiction:
Improverotor position sensing accuracyVSAvoidsensor mounting complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent removes Hall effect sensors from the winding structure and extracts the position sensing function to a separate encoder system. This extraction eliminates the complexity of mounting sensors on windings while improving measurement precision through dedicated encoder technology.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces mechanical Hall effect sensors with an optical or magnetic encoder system that provides higher resolution position feedback. This substitution improves measurement precision by using non-contact sensing methods with finer resolution capabilities.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If conventional closed-loop control is used with Hall effect sensors, then basic motor control is achieved, but control precision for speed, torque, and power is insufficient

Engineering Contradiction:
Improvemotor control precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a closed-loop control system that uses encoder feedback to continuously monitor rotor position and provide real-time correction. This feedback mechanism improves control precision for speed, torque, and power by comparing actual performance with target values and adjusting control signals accordingly.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent employs advanced control algorithms that dynamically adjust control parameters based on operating conditions. By changing control parameters adaptively, the system achieves high precision control across different motor operating points without requiring overly complex hardware.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If traditional motor control methods are used, then basic operation is maintained, but efficiency in controlling motor speed, torque, and power is limited

Engineering Contradiction:
Improvemotor control efficiencyVSAvoidcontrol system energy loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent implements dynamic control strategies that adapt to changing motor operating conditions in real-time. By continuously adjusting control parameters based on actual motor state and load conditions, the system optimizes efficiency across the entire operating range and minimizes energy losses during transitions between operating points.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes control parameters dynamically to optimize efficiency at different operating points. By adjusting current references, switching frequencies, and control gains based on motor speed and torque demands, the system maximizes productivity while minimizing energy losses in the control system.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides precise control over motor speed, torque, and power, enhancing the performance and accuracy of BLDC motors by leveraging advanced signal processing and feedback mechanisms.

Implementation Method 1

along with a phase-locked loop scheme for improved accuracy

Methodology Applied
Scientific EffectPhase-locked loop:

Data Source

PatentEP4008054B1Control method and motor controller IC package for BLDC motor
Publication Date: 2025.07.02 ALLEGRO MICROSYSTEMS LLC
  • EP4008054B1 patent drawingFigure 1
  • EP4008054B1 patent drawingFigure 2
  • EP4008054B1 patent drawingFigure 2A

AI summary

Methods and apparatus to control a three-phase BLDC motor with a curve transformer having an index value for each stored input value and output value for providing stored corner points for outputs of the curve transformer. The curve transformer can output interpolated data for input data between adjacent ones of the input values.