Inverter Coolant Flow Estimation Without Model-Specific Calibration
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Solution Overview
Problem
Existing coolant flow rate estimation methods for electric vehicle powertrains require separate data calibration for different thermal management systems, leading to time-consuming calibration processes and poor practicability.
Innovation Solution
A powertrain system that estimates coolant flow rate in real time using temperature data from specific positions in the cooling loop and power loss of the inverter, without relying on pre-calibrated data from thermal management systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pre-calibrated correspondence data from thermal management systems is used for coolant flow rate estimation, then the estimation can be performed using existing system data, but separate data calibration is required for different vehicle models which increases time consumption and reduces practicability
Solution Approach 1:
The patent extracts the coolant flow rate estimation function from the thermal management system and relocates it to the motor control unit. By using locally available data (inverter temperatures, motor phase currents, electronic pump rotation speed) within the powertrain control unit, the system eliminates the need for separate calibration processes while maintaining estimation accuracy.
Solution Approach 2:
The powertrain control unit performs self-calibration by utilizing its own operational data without requiring external calibration from the thermal management system. The controller calculates coolant flow rate based on temperature differences across the inverter, power loss calculations, and pump rotation speed, making the system self-sufficient and model-agnostic.
2Measurement precision
If separate data calibration is performed for different vehicle models, then accurate coolant flow rate estimation can be achieved for each model, but the process becomes complex and difficult to implement across multiple platforms
Solution Approach 1:
The patent creates a universal coolant flow rate estimation method that can be applied across different vehicle models without modification. The calculation methodology using inverter temperatures, phase currents, and pump rotation speed is model-agnostic and can be implemented in any electric vehicle powertrain, significantly improving ease of manufacture and deployment.
Solution Approach 2:
The patent changes the calibration approach from model-specific pre-calibrated correspondence data to real-time parameter-based calculation. By using dynamically measured parameters (temperatures, currents, rotation speeds) instead of static calibration data, the system achieves both accuracy and universality across different vehicle models.
3Measurement precision
If coolant flow rate is estimated using thermal management system data, then the estimation relies on calibrated correspondence, but this approach requires accessing data from another system which increases system complexity
Solution Approach 1:
The patent merges the coolant flow rate estimation function with the motor control unit. By combining the estimation algorithm with existing powertrain control capabilities and using data already available in the motor control unit (inverter temperatures, phase currents, pump control signals), the system reduces overall complexity by eliminating the need for inter-system data access and integration.
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 eliminates the need for repeated calibration operations across different vehicle models, reducing time overheads and improving the practicability of coolant flow rate estimation while enhancing accuracy.
Implementation Method 1
coolant in the first cooling loop is configured to cool the inverter
Implementation Method 2
electronic pump is configured to drive the coolant to circulate in the first cooling loop
Implementation Method 3
electronic pump is configured to drive the coolant to circulate in the first cooling loop
Implementation Method 4
inverter is configured to convert a direct current provided by a power battery pack into an alternating current
Implementation Method 5
motor is configured to convert the alternating current into mechanical energy
Data Source
AI summary
A powertrain, a coolant flow rate estimation method, and an electric vehicle are provided. Coolant in a first cooling loop of the powertrain is configured to cool an inverter. An electronic pump drives the coolant to circulate in the first cooling loop. When a phase current of a motor is greater than or equal to a preset current value, a controller determines a rotation speed of the electronic pump at a first moment as a first rotation speed, and determines a coolant flow rate at the first moment based on a temperature at a first position in the first cooling loop, a temperature at a second position in the inverter, and a power loss of the inverter. In the solution of this application, data does not need to be separately calibrated for different thermal management systems. This reduces time consumed by data calibration and improves practicability.