Traction Motor LV Generation for EV Emergency Load Power
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Solution Overview
Problem
In electric vehicles, the failure of the high-voltage (HV) battery can result in a short operating time for low-voltage (LV) loads, requiring a large and costly LV battery to compensate, which increases the vehicle's mass and cost.
Innovation Solution
The method involves operating the traction motor as an LV generator in emergency mode, providing power to the LV loads through LV power electronics, eliminating the need for an LV battery during passive travel, and using an LV battery only to stabilize the voltage when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the HV battery fails, then the LV load operating time becomes too short, but increasing the LV battery capacity to extend operating time results in high costs and large mass
Solution Approach 1:
The traction motor is designed to perform multiple functions: during normal operation it serves as a drive motor powered by the HV battery, but during emergency mode it functions as a generator to power LV loads. This multi-functionality eliminates the need for a dedicated LV battery system, resolving the contradiction between extending LV load operating time and reducing vehicle mass.
Solution Approach 2:
The system uses its own existing components (traction motor, HV battery) to serve the LV loads during emergency mode without requiring external or dedicated backup systems. The traction motor generates electricity from the HV battery to power LV loads, enabling the system to self-support during failures and eliminating the need for additional mass.
2Duration of action of moving object
If the HV battery fails, then the LV load operating time becomes too short, but increasing the LV battery capacity to extend operating time results in high costs
Solution Approach 1:
The traction motor performs dual functions as both motor and generator, eliminating the need for a separate LV battery system. This reduces overall system cost by removing redundant components while ensuring continuous LV load operation during HV battery failures.
Solution Approach 2:
The patent merges the LV power supply function into the existing HV power train components. The HV battery and traction motor are combined to serve both HV and LV loads, eliminating the need for separate LV battery infrastructure and reducing system cost.
3Duration of action of moving object
If the traction motor operates as an LV generator during passive travel, then the LV load operating time is extended, but the system complexity increases
Solution Approach 1:
The traction motor serves dual purposes as both motor and generator, utilizing existing components for multiple functions. This approach extends LV load operation without adding dedicated backup systems, managing complexity by repurposing existing infrastructure rather than adding new systems.
Solution Approach 2:
The control unit acts as an intermediary that manages the switching between normal and emergency modes, coordinating the traction motor's operation as generator and the power distribution to LV loads. This centralized control simplifies the overall system architecture by providing a single point of management for the multi-functional components.
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 approach ensures a long operating time for LV loads without increasing the vehicle's mass or cost, maintaining maneuverability even after HV battery failure, and stabilizing the operating voltage.
Implementation Method 1
A traction motor of the electric vehicle is operated as an LV generator while the electric vehicle is traveling in an emergency mode
Data Source
AI summary
A method for operating a low-voltage (LV) load of an electric vehicle, in which an LV load of an electric vehicle is operated with a provided operating voltage, and a drive system for an electric vehicle, and electric vehicle.