EV Drive Torque Control Using Torque-Current Shift Detection
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Solution Overview
Problem
Existing control systems for electric vehicles fail to accurately determine whether the drive torque outputted from the drive motor corresponds to the torque command value, and cannot detect shifts between control parameters that affect the drive torque output.
Innovation Solution
A control apparatus for electric vehicles that includes processors and sensors to detect the output current of the battery and drive torque, calculating the actual torque-current characteristic and comparing it to a reference characteristic to determine shifts and abnormalities in the control parameters of the drive motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the malfunction detection function compares torque command value and drive torque using deviation torque, then it can detect current supply abnormalities, but it cannot detect control parameter abnormalities that affect drive torque output
Solution Approach 1:
The patent transitions from one-dimensional deviation torque comparison to two-dimensional torque-current characteristic analysis. By plotting torque command values against actual current values and comparing the characteristic curves, the system can detect control parameter abnormalities that manifest as shifts in the torque-current relationship, providing detection in an additional dimension beyond simple torque deviation.
Solution Approach 2:
The system continuously monitors the torque-current characteristic and compares it against the reference characteristic, creating a feedback mechanism that detects deviations caused by control parameter abnormalities. This feedback loop enables real-time detection and notification of control system issues.
2Device complexity
If the system only compares torque command value and drive torque, then the detection method remains simple, but it cannot sense shifts in control parameters
Solution Approach 1:
The patent adds the current value dimension to the existing torque comparison method. By analyzing the relationship between torque command values and actual current values through characteristic curves, the system recovers control parameter shift information that would be lost in simple torque comparison, while maintaining relatively simple implementation through curve comparison.
3Reliability
If the malfunction detection determines only current supply appropriateness, then the detection scope remains narrow, but it cannot determine drive torque appropriateness corresponding to torque command value
Solution Approach 1:
The torque-current characteristic comparison method serves multiple functions: it detects current supply abnormalities, drive torque abnormalities, and control parameter shifts all through a single unified analysis approach. This multi-functional detection mechanism enhances both reliability and adaptability of the monitoring system.
Data Source
AI summary
A control apparatus for an electric vehicle acquires a detection value of an output current of a battery to be detected by a first sensor, and a detection value of a drive torque to be transmitted to a wheel and to be detected by a second sensor, calculates an actual torque-current characteristic that indicates a relationship between a supply current to be supplied to an inverter circuit and the drive torque to be transmitted to the wheel, and determines a shift between a reference torque-current characteristic and the calculated actual torque-current characteristic, in which the reference torque-current characteristic is a characteristic in which a relationship between a torque command value of a drive motor and a target supply current to be supplied to the drive motor is set in advance.