Steering Motor Torque Redistribution for Generator-Mode Negative Current
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Solution Overview
Problem
Existing electromechanical steering systems face issues with generator mode operation due to negative currents that can damage electronic components, particularly when DC voltage sources are not configured to handle generated currents, leading to potential damage and inefficiencies.
Innovation Solution
A method for operating a steering system motor with separate winding groups, where one group is connected to a vehicle battery to handle negative currents and the other to a drive battery, allowing torque redistribution to manage negative currents effectively, preventing damage by redirecting them to the vehicle battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a steering system motor with two winding groups is provided for redundancy, then the reliability of the steering system is improved, but the complexity of the circuit arrangement and control units increases
Solution Approach 1:
The motor is divided into two separate winding groups (first and second winding groups) with three phases each, allowing independent control and operation. Each winding group can be activated separately through dedicated circuit arrangements, enabling redundant operation modes while maintaining manageable complexity through modular design
Solution Approach 2:
The steering system motor is designed to perform multiple functions through its two winding groups: it can operate in motor mode for steering actuation and in generator mode for energy recovery. The system can selectively activate different winding groups based on operational requirements, providing versatility while maintaining a unified motor structure
2Ease of manufacture
If the DC voltage sources are not configured to receive generated currents, then the cost is reduced, but the generated currents can cause damage to electronic components
Solution Approach 1:
A DC-DC converter is introduced as an intermediary component between the generator mode winding groups and the DC voltage sources. This converter safely manages the generated currents by converting them to appropriate voltage levels and directing them to suitable storage elements, preventing damage to electronic components while enabling cost-effective system architecture
Solution Approach 2:
The generator mode, which initially produces harmful negative currents, is converted into a beneficial energy recovery mechanism. By configuring the system to capture and store the generated energy in the DC voltage sources or energy storage elements, the previously harmful currents become useful for recharging batteries or recovering kinetic energy
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 prevents damage to electronic components by managing negative currents, ensuring safe operation in generator mode and maintaining system functionality by redirecting excess energy to the vehicle battery.
Implementation Method 1
a generator mode, in which electric currents are generated
Implementation Method 2
a motor mode, in which motor torque is generated by the steering system motor
Data Source
AI summary
A method for operating a steering system motor in a motor vehicle comprises influencing, by the steering system motor, a steering behavior of a steering handle by means of a motor mode or a generator mode, wherein the steering system motor comprises a first and a second winding group, wherein the first winding group and the second winding group are activated separately from each other, the first via a first circuit arrangement with an assigned first control unit, and the second via a second circuit arrangement with an assigned second control unit, wherein the first circuit arrangement is connected to a first DC voltage source, and the second circuit arrangement is connected to a second DC voltage source. For a torque which is to be provided by the steering system motor and requires a generator mode of the steering system motor, a torque redistribution between the first and the second winding group takes place, the first winding group being activated differently from the second winding group, and a greater negative current flow being permitted with respect to the first winding group than with respect to the second winding group. A steering system having a steering system motor can be operated according to this method and a motor vehicle can have such a steering system.