Hybrid Vehicle Inverter Control for Sensor Abnormality
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Solution Overview
Problem
In hybrid vehicles, when an abnormality occurs in the sensor controlling the first inverter during engine stop, the vehicle cannot start the engine, reducing drivable time and distance when relying solely on the second motor's power.
Innovation Solution
Implementing a hybrid vehicle configuration with a three-phase AC motor, planetary gear, and inverters, where the controller performs three phase-on control of the first inverter to turn on all switching elements, and controls the second inverter to output torque to the driveshaft, increasing engine rotation speed and enabling engine start when the engine reaches a predetermined speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the first inverter is controlled with normal switching during sensor abnormality, then control precision is maintained, but the system cannot operate and loses adaptability
Solution Approach 1:
The patent changes the control parameters of the first inverter from normal PWM switching to three-phase-on control (turning on all upper arm switching elements or all lower arm switching elements) when sensor abnormality is detected. This parameter change allows the system to operate in a degraded mode, maintaining basic functionality and adaptability while avoiding the need for precise sensor feedback.
2Adaptability or versatility
If three phase-on control is implemented to enable operation during sensor abnormality, then system adaptability is improved, but device complexity increases
Solution Approach 1:
The control system dynamically adjusts the inverter operating mode based on sensor status. The controller monitors sensor health and automatically switches between normal PWM control and three-phase-on control, managing complexity through conditional logic rather than requiring separate hardware systems for each mode.
3Device complexity
If the system relies solely on the second motor for propulsion during sensor abnormality, then device complexity is reduced, but drivable time and distance are reduced
Solution Approach 1:
The first motor serves as an intermediary energy storage and transfer mechanism. During sensor abnormality, it can be driven by the second motor to generate electrical energy that charges the battery or directly powers the second motor, extending drivable time and distance while maintaining relatively simple control architecture.
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
This configuration increases the drivable time and distance by using the second motor's power by generating torque to maintain engine rotation speed and charge the battery through back electromotive force, even when the first motor fails to crank the engine.
Implementation Method 1
the first motor that generates a back electromotive force accompanied with rotation
Data Source
AI summary
In the state where a sensor used for controlling a first inverter has an abnormality, when rotation speed Ne of an engine is lower than a predetermined reference value Nref (S120), three phase-on control of a first inverter is performed (S190). This causes the rotation speed of the engine to be increased with an increase in rotation speed of a driveshaft. Operation control of the engine is started when the rotation speed Ne of the engine reaches or exceeds a threshold value Nst (S210 to S230).