Vehicle Motor Control via Sensorless Estimation After Position Failure
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Solution Overview
Problem
In electric vehicles, a failure of the position sensor of the motor rotor can disrupt motor control, leading to abnormal driving force and safety concerns, as existing systems often halt motor control when a fault is detected, preventing the vehicle from operating according to the driver's intention.
Innovation Solution
A method and system that utilize a sensorless estimation algorithm to derive and switch to alternative position information, compensating for errors based on direct current values when the position sensor fails, allowing continuous vehicle operation by integrating motor speed and initial rotor position information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inverter stops current control when position sensor failure is detected, then system reliability is improved by preventing abnormal operation, but vehicle operability deteriorates as the vehicle cannot continue driving
Solution Approach 1:
The system performs preliminary actions by storing third position information and motor speed before failure occurs, and pre-preparing sensorless estimation algorithms to enable seamless transition when position sensor failure is detected, allowing continuous vehicle operation
Solution Approach 2:
The controller acts as an intermediary by introducing sensorless estimation as a intermediate solution between position sensor failure and complete system shutdown, enabling the system to continue operating using estimated position information instead of stopping entirely
2Measurement precision
If the inverter interrupts current control upon position sensor failure, then measurement precision is improved by avoiding distorted position information, but vehicle safety deteriorates due to loss of driver control
Solution Approach 1:
The system extracts only the necessary elements (third position information and motor speed before failure) to continue operation through sensorless estimation, separating the failure of position sensor from complete system shutdown by using alternative estimation methods
Solution Approach 2:
The system uses feedback by continuously monitoring position sensor status and switching to sensorless estimation when failure is detected, with the ability to compensate for estimation errors through sensed direct current values to maintain accurate motor control
3Productivity
If sensorless estimation algorithm is used after position sensor failure, then vehicle operability is improved by enabling continuous driving, but measurement precision deteriorates due to estimation errors
Solution Approach 1:
The system replaces the mechanical position sensor with a sensorless estimation algorithm that uses electrical measurements (direct current sensing) and stored operational data to estimate rotor position, eliminating dependency on the failed mechanical sensor
Solution Approach 2:
The system changes parameters by switching from direct position sensor measurements to estimated position parameters derived from motor current and speed, with compensation mechanisms that adjust estimation accuracy based on sensed direct current values
Data Source
AI summary
A method and a system for controlling a motor for a vehicle are provided. The vehicle is capable of being continuously driven by controlling the motor based on position information of a rotor derived using a sensorless estimation algorithm in the event of a failure of a position sensor of a motor rotor while the vehicle is being driven.