Predictive Voltage Boost for Electric Motor Driveline Damping
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Solution Overview
Problem
Conventional active electric motor damping (AEMD) systems in electrified vehicles suffer from inefficiencies due to the use of a constant voltage margin for DC-DC boost converters, leading to unnecessary higher boost voltages and reduced efficiency during transient maneuvers, which affects fuel economy and drivability.
Innovation Solution
A predictive AEMD control system that dynamically determines an AEMD torque boost voltage margin based on operating parameters, such as motor torque and speed, using a calibrated surface to optimize the boost voltage only when necessary, thereby improving efficiency and reducing driveline vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant voltage margin is used for DC-DC boost converter in AEMD systems, then the system can provide sufficient torque capability during transient maneuvers, but the boost voltage remains unnecessarily high during steady-state operation, reducing overall efficiency
Solution Approach 1:
The patent applies dynamics by transitioning from a static constant voltage margin to a dynamic predictive voltage margin that adapts to changing operating conditions. The control system continuously predicts the required AEMD torque and adjusts the voltage margin accordingly, ensuring sufficient torque capability during transient maneuvers while reducing voltage margin during steady-state operation to improve efficiency.
Solution Approach 2:
The patent changes the parameter of voltage margin from a fixed constant value to a variable parameter that is dynamically adjusted based on predicted AEMD torque requirements. This parameter change allows the system to optimize the balance between torque capability and energy efficiency across different operating conditions.
2Power
If the DC-DC boost converter maintains high boost voltage continuously, then the electric motor has higher torque capacity, but the conversion efficiency of the boost converter decreases
Solution Approach 1:
The patent applies preliminary action by using a predictive controller that anticipates future AEMD torque requirements before they occur. The system predicts the needed torque and adjusts the voltage margin in advance, allowing the boost converter to maintain high torque capacity only when actually needed, rather than continuously, thereby improving conversion efficiency.
Solution Approach 2:
The patent applies partial action by providing high voltage margin and torque capacity only partially - specifically during transient maneuvers when AEMD torque is actually required - rather than maintaining excessive voltage margin continuously. This selective application of high power improves overall system efficiency.
3Loss of energy
If a predictive voltage margin approach is used, then the system efficiency improves by reducing unnecessary boost voltage, but the control system complexity increases
Solution Approach 1:
The patent applies feedback by implementing a predictive control system that continuously monitors operating conditions (motor speed, torque requests, vehicle speed) and adjusts the voltage margin based on predicted AEMD torque requirements. This closed-loop feedback mechanism enables efficient voltage management while keeping the control logic systematic and manageable.
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
The system enhances efficiency by providing AEMD torque only when needed, improving drivability and reducing drivetrain vibrations while maintaining optimal fuel economy.
Implementation Method 1
a direct current to direct current (DC-DC) boost converter that to boosts or steps-up voltage from a battery system
Implementation Method 2
at least one electric motor configured to generate torque that is provided to a driveline for vehicle propulsion
Implementation Method 3
active electric motor damping (AEMD) utilizes a torque modifier where the torque applied to the electric motor is damped to reduce or mitigate the driveline vibrations
Data Source
AI summary
An active electric motor damping (AEMD) control system for an electrified powertrain of a vehicle involves dynamically determining, based on a set of operating parameters of an electric motor, an AEMD torque boost voltage margin for a direct current to direct current (DC-DC) boost converter of the electrified powertrain, wherein the AEMD torque boost voltage margin is an additional voltage for increasing a torque capability of the electric motor, outputting, to the DC-DC boost converter, the AEMD torque boost voltage margin, wherein receipt of the AEMD torque boost voltage margin causes the DC-DC boost converter to boost a first voltage from a battery system of the electrified powertrain to a higher second voltage, and controlling the electric motor using the higher second voltage to dampen vibrations at a driveline of the vehicle.