# US 12,111,193 B2 · Method for determining a target volumetric flow rate for a coolant

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- Number: US 12,111,193 B2
- Document ID: US12111193B2
- Status: Granted
- Kind: B2
- Application number: 17/770,791
- Filed: 2020-09-23
- Published: 2022-11-24
- Granted: 2024-10-08
- Earliest claimed: 2019-10-22
- Assignees: Robert Bosch GmbH
- Applicants: Robert Bosch GmbH
- Inventors: Jakob Mauer
- Web page: https://patentgrep.com/patent/US12111193B2

## CPC

- G01F 1/68: by using thermal effects
- H05K 7/20927: {Liquid coolant without phase change}
- H05K 7/20945: {Thermal management, e.g. inverter temperature control}
- G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

The invention relates to a method for determining a target volumetric flow rate (V) 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 (V) is determined on the basis of the temperature (TC) of the DC-link capacitor and the temperature (TK) of the coolant.

## Claims

### Claim 1

A method for determining a target volumetric flow rate (V) for a coolant (180), which is conducted through a coolant path (164) to cool a power converter (110), the method comprising:
determining a temperature (TC) of a DC-link capacitor (135) of the power converter (110) and a temperature (TK) of the coolant, and
determining, via an electronic controller, a value for the target volumetric flow rate (V) based on the temperature (TC) of the DC-link capacitor and the temperature (TK) of the coolant, and
wherein the value for the target volumetric flow rate (V) is determined based on a temperature difference (ΔT), between the temperature (TC) of the DC-link capacitor and the temperature (TK) of the coolant, and the temperature of the coolant (TK), and
wherein at least one value of a current is determined in the power converter, and wherein based on the at least one value of the current, an intermediate value (VZ) for the target volumetric flow rate determined from the temperature (TC) of the DC-link capacitor and the temperature of the coolant (TK), is adapted via the electronic controller and used as the value for the target volumetric flow rate (V), and
controlling flow of coolant, via a coolant pump (190), through the coolant path (164) at the target volumetric flow rate (V).

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein (i) a value of a current (IZ) in a DC link of the power converter, (ii) a value of a phase current (IP), or both (i) and (ii) are used as the at least one value of the current in the power converter.

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein a time interval (Δt) between two successive determinations of the value for the target volumetric flow rate (V) is predefined as a function of a change of a current in the power converter.

### Claim 4 (depends on 3)

The method as claimed in claim 3, wherein upon an increase of the current in the power converter, a longer time interval is predefined than upon a decrease of the current in the power converter.

### Claim 5 (depends on 1)

The method as claimed in claim 1, wherein the coolant pump (190) for the coolant (180) is activated based on the determined target volumetric flow rate (V).

### Claim 6 (depends on 1)

The method as claimed in claim 1, wherein the target volumetric flow rate (V) is scaled based on the at least one value of the current.

### Claim 7 (depends on 1)

The method as claimed in claim 1, wherein the value for the target volumetric flow rate (V) is determined based on a characteristic map (K1).

### Claim 8

A non-transitory, computer-readable storage medium having instructions that when executed by a computer cause the computer to determine a target volumetric flow rate (V) for a coolant (180), which is conducted through a coolant path (164) to cool a power converter (110), by:
determining a temperature (TC) of a DC-link capacitor (135) of the power converter (110) and a temperature (TK) of the coolant, and
determining a value for the target volumetric flow rate (V) based on the temperature (TC) of the DC-link capacitor and the temperature (TK) of the coolant, and
wherein the value for the target volumetric flow rate (V) is determined based on a temperature difference (ΔT), between the temperature (TC) of the DC-link capacitor and the temperature (TK) of the coolant, and the temperature of the coolant (TK), and
wherein at least one value of a current is determined in the power converter, and wherein based on the at least one value of the current, an intermediate value (VZ) for the target volumetric flow rate determined from the temperature (TC) of the DC-link capacitor and the temperature of the coolant (TK), is adapted based on a characteristic map (K1) and used as the value for the target volumetric flow rate (V), and
controlling flow of coolant, via a coolant pump (190), through the coolant path (164) at the target volumetric flow rate (V).