Electric Drive Unit Heating Through dq Current Trajectories
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Solution Overview
Problem
Electric vehicles and hybrid electric vehicles face complexity and inefficiency in thermal management due to the need for additional heat sources, which complicate the system and increase component count.
Innovation Solution
A method and apparatus that utilize an electric drive unit with a polyphase AC motor and inverter, controlled by a field-oriented controller in a dq reference frame, to generate heat by selecting predetermined current trajectories based on torque and heat level requests, optimizing heat production within the electric drive system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If additional heat source components are added to the electrified vehicle, then heat generation capability is improved, but device complexity increases
Solution Approach 1:
The electric drive unit is made multi-functional by enabling it to perform both its primary function (mechanical work through the AC motor) and a secondary function (heat generation). The controller selectively commands current trajectories that produce heat in the motor windings and inverter components, allowing the existing electric drive system to serve dual purposes without adding dedicated heat source components.
Solution Approach 2:
The electric drive unit serves itself by generating its own heat through controlled electrical current paths. The system uses its existing components (AC motor windings, inverter power devices) to generate heat through resistive heating effects when commanded to do so, eliminating the need for external or additional heating systems.
2Temperature
If dedicated heat source components are added, then thermal management capability is improved, but manufacturing cost increases
Solution Approach 1:
The electric drive unit is designed to perform multiple functions including propulsion and thermal management. By controlling the inverter and motor to operate in heat-generating modes when needed, the system eliminates the need for separate heating components, thereby reducing manufacturing costs while maintaining thermal management capability.
3Temperature
If heat is generated by additional components, then heat production is improved, but loss of energy increases
Solution Approach 1:
The system converts what would normally be wasted energy (resistive losses in motor windings and inverter components) into useful heat. By deliberately commanding current trajectories that produce heat, the system transforms energy that would otherwise be lost as waste heat into a beneficial thermal resource for cabin heating or battery thermal management.
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 allows for efficient heat generation within the electric drive unit, reducing system complexity and improving thermal management by leveraging existing electric drive components, thereby enhancing the vehicle's thermal management capabilities.
Implementation Method 1
A method and apparatus that utilize an electric drive unit with a polyphase AC motor and inverter, controlled by a field-oriented controller in a dq reference frame, to generate heat by selecting predetermined current trajectories
Data Source
AI summary
An electric drive unit includes a polyphase alternating current (AC) motor, an inverter. A motor controller employs field oriented controls to achieve torque and heat production objectives for the electric drive unit. Additional heat may be generated through inverter operation control.