Electric Drive Thermal Management with Variable Coolant Distribution
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Solution Overview
Problem
Existing thermal management systems for electrical drive systems, such as those in vehicles, lack the ability to variably cool individual components, leading to inefficiencies and limited performance, especially at partial load points and in terms of service life.
Innovation Solution
A thermal management system where the electric motor and power electronics are in spatial contact with separate cooling units, connected through an electrically controlled coolant distributor with a multiway valve for demand-based coolant distribution, allowing for selective cooling and efficient thermal operating point adjustment, enabling continuous power delivery and enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single integrated coolant circuit is used to cool both power electronics and electric motor, then the system structure is simple and integration cost is reduced, but the ability to selectively cool individual components is lost
Solution Approach 1:
The coolant distributor divides the single coolant circuit into separate parallel branches, each leading to individual cooling units for power electronics and electric motor. This segmentation enables selective cooling of components while maintaining a relatively simple integrated system structure with shared coolant pump and reservoir.
Solution Approach 2:
The system incorporates controllable valves in each parallel branch that can dynamically adjust or completely block coolant flow to specific cooling units. This dynamic control allows the system to adapt cooling distribution based on real-time thermal demands of different components, transforming a static single-circuit system into a dynamically adjustable selective cooling system.
2Reliability
If coolant flow is distributed to all cooling units continuously, then all components are cooled uniformly, but energy efficiency decreases especially at partial load points
Solution Approach 1:
Controllable valves in each parallel branch dynamically adjust coolant flow distribution based on actual thermal demands of power electronics and electric motor. At partial load points, the system reduces or stops cooling to components that do not require it, significantly improving energy efficiency while maintaining reliable temperature control when needed.
Solution Approach 2:
The system changes the flow rate parameter of coolant to each cooling unit based on operational conditions. By adjusting flow rates from zero to maximum depending on thermal load, the system optimizes energy consumption while ensuring components maintain safe operating temperatures.
3Ease of manufacture
If the coolant circuit is built into the cooling cover as integrated, then manufacturing is simplified, but the cooling of individual components cannot be varied or optimized
Solution Approach 1:
The coolant distributor segments the integrated coolant circuit into separate controllable branches, allowing independent optimization of cooling for power electronics and electric motor while maintaining the benefits of integrated manufacturing with shared pump and reservoir.
Solution Approach 2:
Dynamic valve control in each branch enables the system to optimize cooling distribution based on real-time power delivery requirements. This allows continuous power delivery when both components need cooling, while reducing energy consumption when only one component requires cooling or neither does.
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 solution increases the efficiency and service life of the electrical drive system by allowing demand-led cooling, reduces integration costs, and enables air conditioning of the vehicle interior, providing comfort and performance advantages.
Implementation Method 1
the power electronics and the electric motor are in spatial contact with separate cooling units, wherein the cooling units are disposed in parallel with each other... cooled by a coolant circulating in the cooling circuit
Implementation Method 2
the coolant is circulated by a coolant pump
Implementation Method 3
an electrically controlled coolant distributor comprising two outputs is positioned between the coolant pump and the cooling units
Data Source
AI summary
A thermal management system for an electric drive system, preferably for a vehicle, includes an electric drive including an electric motor and power electronics. The electric motor and the power electronics are integrated in a cooling circuit and are cooled by a coolant circulating in the cooling circuit. The coolant is circulated by a coolant pump. In the case of a variable thermal management system, the electric motor and the power electronics are in spatial contact with respective cooling units. The cooling units of the electric motor and of the power electronics are arranged parallel to each other and an electrically controlled coolant distributor is positioned between the coolant pump and the cooling units which coolant distributor has two outlets. One outlet leads to the cooling unit of the electric motor and one outlet leads to the cooling unit of the power electronics and the outlets of the cooling units are merged into a channel and led back to the coolant pump.