Steering Motor Current Control Under Phase Sensor Failure
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Solution Overview
Problem
Existing motor control systems fail to address the issue of noise and vibration in vehicles, particularly in vehicles, particularly in vehicles, particularly in vehicles, due to the failure of phase current sensors in electronic steering devices, leading to potential steering instability and safety hazards.
Innovation Solution
A motor control device and method that employs three current sensors per phase in a three-phase inverter, with a controller capable of determining an estimated current based on the number of faulty sensors, ensuring safe steering through fault-tolerant control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed-loop control using phase current sensors is implemented, then current control precision is improved, but system reliability deteriorates when sensor failure occurs
Solution Approach 1:
The controller performs preliminary fault detection by monitoring current sensor outputs and comparing them against expected values. When a sensor failure is detected, the system proactively switches to open-loop control mode before the failure can cause steering instability or safety hazards, thereby maintaining reliable operation despite the sensor malfunction
Solution Approach 2:
The system dynamically changes the control parameter from closed-loop (using sensor feedback) to open-loop (using command current directly) based on the detected sensor failure condition. This parameter change allows the system to maintain functional operation by adapting the control strategy to the degraded sensor state
2Reliability
If fault tolerant control with estimated current is implemented, then steering safety is improved during sensor failure, but control precision deteriorates compared to closed-loop control
Solution Approach 1:
The system prepares compensatory control measures in advance by implementing fault detection and switching capabilities. When sensor failure occurs, the pre-planned fallback to open-loop control with estimated current provides a cushioning effect that prevents complete system failure and maintains basic steering safety despite the loss of precise current measurement
3Reliability
If three current sensors per phase are used, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
The system applies different quality levels to different phases by using three current sensors only in phases where precise measurement is critical, while relying on estimation or fewer sensors in other phases. This local differentiation optimizes the balance between measurement reliability and device complexity by placing sensors strategically rather than uniformly throughout the system
Data Source
AI summary
The embodiments may provide a motor control device including three current sensors provided in each phase of a three-phase inverter connected to a motor to detect a current of each phase, and a controller configured to generate a control signal for the motor based on a detected current, and, in case of a failure of at least one of the three current sensors, determine an estimated current based on the number of faulty current sensors with the failure and generate a control signal for the motor based on the estimated current. According to the embodiments, it is possible to implement a motor control device capable of protecting the safety of a driver through a fault tolerant control in case of a failure of a current sensor.