Sensorless Field-Oriented Control for Brushless Motor Torque Ripple
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing brushless motor control systems, particularly those using scalar control, suffer from inefficiencies such as low torque production, high torque ripple, vibration, noise, and decreased motor life, which are not effectively addressed in miniaturized, battery-powered systems for personal electric vehicles.
Innovation Solution
A sensorless field-oriented control method is implemented using a software-based sensor to monitor stator voltages and currents, calculate rotor flux and angle, and generate motor commands, eliminating the need for physical sensors and improving control precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If scalar control is used, then the control system is inexpensive and easy to implement, but torque production is low and torque ripple is high
Solution Approach 1:
The patent replaces traditional scalar control methods with field-oriented control (FOC) algorithms that use mathematical models and coordinate transformations (Park transform, Clarke transform) to achieve superior torque control. This substitution of control methodology enables precise torque production while maintaining computational efficiency suitable for miniaturized systems.
2Ease of manufacture
If scalar control is used, then the control system is inexpensive and easy to implement, but vibration and noise increase
Solution Approach 1:
The patent replaces scalar control with field-oriented control algorithms that produce sinusoidal current waveforms instead of trapezoidal waveforms. This substitution eliminates the commutation harmonics and torque ripple that cause vibration and noise, while the computational approach remains suitable for miniaturized embedded systems.
3Device complexity
If scalar control is used, then the control system is simple, but energy efficiency decreases and motor life decreases
Solution Approach 1:
The patent replaces scalar control with field-oriented control that optimizes the magnetic field orientation and current distribution in the motor windings. This substitution improves energy efficiency by minimizing losses through precise field alignment, while the algorithmic approach remains computationally efficient for miniaturized systems.
4Measurement precision
If physical sensors are used for rotor position detection, then control precision is achieved, but device complexity and cost increase
Solution Approach 1:
The patent creates a virtual copy of the rotor position sensor through software-based estimation algorithms. By using motor phase currents and voltages along with mathematical models (Park transform, Clarke transform) to estimate rotor position and speed, the system achieves sensor-level measurement precision without physical sensors, thereby reducing complexity and cost.
Solution Approach 2:
The patent replaces physical rotor position sensors with a software-based sensor that uses mathematical modeling and signal processing. This substitution eliminates mechanical or electronic sensors while achieving equivalent or superior measurement precision through field-oriented control algorithms.
Data Source
AI summary
An electronic speed control system and method is disclosed to control motors that power a load. The electronic speed control system is configured to monitor the motors, accept user commands for the motors, to process these inputs along with various motor parameters and/or models, and to generate motor commands to send to the motors. A field oriented control method continuously monitors voltages and currents from each motor phase; accesses the motor parameters; uses a model of the motor to calculate motor rotor flux, angle and speed based on the stator voltages and currents and the motor parameters; and generates motor commands for controlling the motor based on the user commands and the calculated values. The electronic speed control system can also control external accessories, and/or communicate with external applications which can include a motor identification system that can provide the motor parameters and model for the motor.