Electromechanical Steering Vector Control for Generator Current Feedback
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Solution Overview
Problem
Existing electromechanical steering systems face issues with generated electric currents in generator mode, which can damage electronics due to unsuitable on-board power supply systems, particularly in hybrid or electric vehicles, necessitating costly DC/DC converters to manage these currents.
Innovation Solution
The method involves operating the first electric motor in a motor or generator mode based on driving situations, using vector control with a d/q system to convert generated currents energetically, adapting the d-vector to compensate for these currents, and utilizing a DC/DC converter for battery current provision, ensuring the system operates efficiently without affecting steering feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electric motor is operated in generator mode to recover energy, then energy efficiency is improved, but generated currents can damage electronics components due to unsuitable on-board power supply systems
Solution Approach 1:
The patent converts the harmful generated currents into beneficial energy recovery by operating the electric motor in generator mode. The control unit manages the generated currents through field-oriented control, transforming what would be damaging feedback into useful regenerative braking energy that can be stored in the battery, thus resolving the contradiction between energy efficiency and component protection
Solution Approach 2:
The patent changes the operational parameters of the electric motor by switching between motor mode and generator mode based on driving situations. The control unit adjusts the d-vector and q-vector parameters in the field-oriented control system to optimize performance in each mode, allowing the system to recover energy when appropriate while preventing harmful current feedback through proper parameter management
2Reliability
If a DC/DC converter is added to manage generated currents, then protection against current damage is improved, but device complexity and cost increase
Solution Approach 1:
The patent enables the electric motor to serve itself by converting generated currents into useful energy through generator mode operation. The field-oriented control system with d/q vector management allows the motor to self-regulate the generated currents, eliminating the need for external DC/DC converters and reducing system complexity while maintaining reliability
Solution Approach 2:
The patent makes the electric motor multi-functional by enabling it to operate in both motor mode for driving the steering system and generator mode for energy recovery. This universal operation capability allows the single motor to perform multiple functions that would otherwise require separate components, reducing overall system 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
This approach effectively prevents damage from generated currents, maintains steering behavior, and reduces the need for costly DC/DC converters by converting currents within the electric motor, thus protecting the on-board power supply system.
Implementation Method 1
the first electric motor is controlled by a first control unit by means of vector control, wherein a d-vector having an associated current I_d and a q-vector having an associated current I_q of a rotor-referred d/q system for the first electric motor are influenced by means of a first controller of the first control unit
Implementation Method 2
wherein the d-vector of the rotor-referred d/q system for the first electric motor is adapted for the energetic conversion of a current that is generated by the first electric motor in generator mode
Data Source
AI summary
A method for operating an electromechanical steering system in a motor vehicle, wherein the steering system includes a first actuator having a first electric motor, comprises operating the first electric motor in a motor mode or a generator mode depending on a driving situation and, in generator mode, actuating the first electric motor in such a way that a generated current is converted energetically by the first electric motor. The first electric motor is controlled by a first control unit by vector control, wherein a d-vector and a q-vector of a rotor-referred d/q system for the first electric motor are influenced by a first controller of the first control unit, and wherein the d-vector for the first electric motor is adapted for the energetic conversion of the generated current. A battery current is provided via a supply line for operation of the first electric motor, wherein a battery current setpoint is defined as the input for the first controller for a generator mode of the first electric motor. An electromechanical steering system comprises a first actuator having a first electric motor and a first control unit, wherein the steering system is designed to be operated according to an aforementioned method.