Coolant Pump Control for Power Converter Thermal Management

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Solution Overview

Problem

Existing methods for determining a target volume flow of coolant for power converters, such as those in electric vehicles, are inefficient as they do not accurately account for the temperature of intermediate circuit capacitors, leading to suboptimal cooling and unnecessary energy consumption.

Innovation Solution

A method that determines a target volume flow for coolant by measuring and considering the temperature difference between the intermediate circuit capacitor and the coolant, using a characteristic map to adjust the coolant pump's operation based on current values, ensuring efficient heat dissipation and reducing energy usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the coolant volume flow is increased to improve cooling efficiency, then the temperature control of the power converter is improved, but the energy consumption of the coolant pump increases

Engineering Contradiction:
Improvetemperature control of power converterVSAvoidenergy consumption of coolant pump
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic adjustment of the coolant volume flow rate based on real-time temperature measurements of the intermediate circuit capacitor and coolant. The control unit continuously monitors temperatures and adjusts the pump operation accordingly, transitioning from static to dynamic control to optimize the balance between cooling efficiency and energy consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the coolant pump by adjusting the volume flow rate based on temperature differences. The system modifies the flow rate parameter dynamically according to the measured temperature of the intermediate circuit capacitor and coolant temperature, optimizing cooling performance while minimizing energy consumption.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the coolant volume flow is decreased to reduce energy consumption, then the energy efficiency is improved, but the cooling efficiency and temperature control deteriorate

Engineering Contradiction:
Improveenergy efficiency of coolant pumpVSAvoidcooling efficiency of power converter
Core Design Contradiction:
Use of energy by moving objectVSTemperature

Solution Approach 1:

The patent implements a feedback control mechanism where the control unit continuously monitors the temperature of the intermediate circuit capacitor and the coolant temperature, then adjusts the coolant volume flow rate accordingly. This closed-loop feedback system ensures that the cooling performance is maintained while optimizing energy consumption by adjusting the flow rate based on actual thermal conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static coolant flow control to dynamic control based on real-time temperature feedback. The coolant pump operation is continuously adjusted according to the measured temperature difference between the intermediate circuit capacitor and coolant, ensuring optimal cooling efficiency at each operating point while minimizing energy consumption.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If the coolant pump is switched off to save energy, then the energy consumption is reduced, but the cooling function is lost and temperature control fails

Engineering Contradiction:
Improveenergy consumption of coolant pumpVSAvoidcooling function reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies partial action by adjusting the coolant volume flow rate to the minimum necessary level based on thermal conditions rather than continuous full operation or complete shutdown. The system determines the optimal flow rate that provides sufficient cooling while minimizing energy consumption, avoiding both excessive cooling and complete shutdown.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The coolant pump operation is dynamically adjusted between different flow rates including potential shutdown based on real-time temperature conditions. The control unit continuously evaluates the thermal state and adjusts the pump operation accordingly, ensuring the cooling function is maintained only when necessary while maximizing energy savings during low-thermal-load conditions.

Inventive Principle:
Principle #15Dynamics

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 precise control of the coolant pump, optimizing cooling efficiency and potentially switching it off temporarily, thereby saving energy and reducing emissions.

Implementation Method 1

a coolant is guided along it in a coolant path to dissipate the generated heat

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a coolant pump, by means of which the coolant is pumped or guided along the coolant path

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4049519B1Method for determining a target volumetric flow rate for a coolant
Publication Date: 2024.12.18 ROBERT BOSCH GMBH
  • EP4049519B1 patent drawingFigure 1
  • EP4049519B1 patent drawingFigure 2
  • EP4049519B1 patent drawingFigure 3

AI summary

The invention relates to a method for determining a target volumetric flow rate (V̇) for a coolant that is conducted through a coolant path in order to cool a power converter, wherein: the temperature (TC) of a DC-link capacitor of the power converter and the temperature (TK) of the coolant are determined, and a value for the target volumetric flow rate (V̇) is determined on the basis of the temperature (TC) of the DC-link capacitor and the temperature (TK) of the coolant.