Hybrid Vehicle Controller Redundancy for Engine Starting
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Solution Overview
Problem
In hybrid vehicles, when an abnormality occurs in the first controller, it is not possible to control the first motor generator, leading to a loss of engine starting capability and reduced retreat traveling distance.
Innovation Solution
A hybrid vehicle configuration that includes a second controller capable of outputting a third control signal to the first inverter, allowing the engine to be started even if the first controller fails, by short-circuiting the first motor generator through the inverter and using the planetary gear mechanism to generate torque for engine rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first controller is used to control the first motor generator, then the engine can be started and power generation can be performed, but when an abnormality occurs in the first controller, the engine starting capability is lost and retreat traveling distance is reduced
Solution Approach 1:
The second controller is designed to perform multiple functions: it controls the second motor generator under normal conditions and can also control the first inverter to enable engine starting when the first controller fails. This multi-functionality ensures engine starting capability is maintained even when the first controller has an abnormality, resolving the contradiction between reliability and device complexity.
2Reliability
If the second controller controls both the second inverter and the first inverter, then engine starting is possible even with first controller failure, but the control system complexity increases
Solution Approach 1:
A selection circuit is introduced as an intermediary component that automatically routes control signals based on the operational status of the first controller. When the first controller is normal, it directly controls the first inverter. When the first controller fails, the selection circuit switches to route control signals from the second controller to the first inverter. This intermediary mechanism resolves the contradiction by managing control signal routing complexity while ensuring reliable engine starting capability.
3Force
If the first motor generator is short-circuited through the first inverter to start the engine, then engine rotation is achieved, but the control signal must simultaneously manage both inverters
Solution Approach 1:
The control system is segmented into distinct functional modules: the second controller generates control signals for the second inverter, while a separate selection circuit handles the routing logic for the first inverter based on system status. This segmentation allows the torque generation function to be maintained while distributing the control signal management complexity across multiple specialized components, resolving the contradiction between achieving engine rotation and managing control complexity.
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
Enables the engine to be started and power generated during retreat traveling, improving the traveling distance by supplying electric power to the second motor generator even when the first controller is abnormal.
Implementation Method 1
a first inverter configured to convert electric power between the battery and the first motor generator
Implementation Method 2
a second inverter configured to convert electric power between the battery and the second motor generator
Implementation Method 3
a planetary gear mechanism configured to connect the engine, the first motor generator, and the output shaft to one another
Implementation Method 4
The first motor generator primarily functions as a power generator, and electric power generated by the first motor generator is supplied to the battery and the second motor generator
Implementation Method 5
The second motor generator is driven with electric power supplied from the battery and the second motor generator, and applies power to the output shaft
Data Source
AI summary
A hybrid vehicle includes a first controller configured to output a first control signal for a first inverter, a second controller configured to output a second control signal for a second inverter and a third control signal for the first inverter, and a selection circuit configured to output either of the first control signal or the third control signal to the first inverter. The third control signal is a signal for simultaneously turning on either of upper arm switching elements or lower arm switching elements of a plurality of arms of the first inverter. The second controller starts an engine by outputting the third control signal while outputting the second control signal to drive a second motor generator when abnormality occurs in the first controller.