System and method for temperature estimation of inverter AC power bus

Patent metadata

Field	Value
Publication number	US-12296693-B2
Application number	US-202318350890-A
Country	US
Kind code	B2
Filing date	Jul 12, 2023
Priority date	Jul 12, 2023
Publication date	May 13, 2025
Grant date	May 13, 2025

Abstract

A system for controlling operation of a vehicle having a power inverter module includes an alternating current (AC) power bus coupled to the power inverter module. The AC power bus has a plurality of busbars for conducting an AC current having multiple phases. The AC power bus is coupled to a stator in an electric motor configured to generate torque to propel the vehicle. A controller is adapted to determine an estimated temperature of the AC power bus for the multiple phases based on a plurality of factors. The plurality of factors includes an oil flow rate of a motor oil and a coolant flow rate of an inverter coolant that are in respective direct or indirect thermal contact with the plurality of busbars. The controller is adapted to control operation of the vehicle based in part on a highest one of the estimated temperature of the multiple phases.

First claim

What is claimed is:

1. A system for controlling operation of a vehicle having a power inverter module, comprising:
an alternating current (AC) power bus coupled to the power inverter module, the AC power bus having a plurality of busbars for conducting an AC current having multiple phases;
an electric motor configured to generate torque to propel the vehicle, the AC power bus being coupled to a stator in the electric motor;
an inverter coolant and motor oil in respective direct or indirect thermal contact with the plurality of busbars;
a controller adapted to determine an estimated temperature of the AC power bus for each of the multiple phases based on a plurality of factors, the controller having a processor and tangible, non-transitory memory on which instructions are recorded;
wherein the plurality of factors includes an oil flow rate of the motor oil and a coolant flow rate of the inverter coolant; and
wherein the controller is adapted to control operation of the vehicle based in part on a highest one of the estimated temperature of the multiple phases.

2. The system of claim 1 , further comprising:
a common-mode choke in thermal communication with the plurality of busbars; and
wherein the plurality of factors includes an estimated choke heat for the common-mode choke, the estimated choke heat being based in part on a switching frequency, a modulation index, and a PWM type of the power inverter module.

3. The system of claim 2 :
wherein the estimated choke heat (Q choke ) for each of the multiple phases may be obtained as:

Q

choke

=

[

Q

base

*

f

sw

K

fsw

*

K

PWM

*

K
MI

]

;

 and
wherein Q base is a calibratable value for base heat loss, f sw is the switching frequency, K fsw is a calibratable scalar value for the switching frequency, and K MI , K PWM are respective calibratable values based on the modulation index and PWM type, respectively.

4. The system of claim 1 , wherein controlling operation of the vehicle includes determining an inverter capability of the power inverter module based in part on the estimated temperature, and derating the torque based in part on the inverter capability.

5. The system of claim 4 , wherein the vehicle includes a secondary inverter, controlling operation of the vehicle including load sharing with the secondary inverter based in part on the inverter capability.

6. The system of claim 1 :
wherein determining the estimated temperature of the AC power bus includes initializing to a starting temperature for each of the multiple phases; and
wherein the starting temperature based in part on a key-off temperature of the AC power bus at a vehicle shutdown, an elapsed time between the vehicle shutdown and a vehicle restart, a calibratable time constant for the AC power bus and a projected cool-down temperature for the AC power bus.

7. The system of claim 6 :
wherein the starting estimated temperature (T ACBB ) of the AC power bus is obtained as: T ACBB =[T Cint +(T Keyoff −T Cint )*e −t inactv *τ ]; and
wherein T KeyOff is the key-off temperature of the AC power bus when the vehicle was shutdown, t inactv is the elapsed time between a vehicle shutdown and a vehicle restart, t is the calibratable time constant for the AC power bus, and T CInt is the projected cool-down temperature for the AC power bus.

8. The system of claim 1 , wherein the plurality of factors includes respective electrical resistances of the plurality of busbars, the respective electrical resistances being based on a respective calibratable nominal electrical resistance of the plurality of busbars at 25 C (R 25C ), the estimated temperature (T ACBB ), and a temperature coefficient of copper.

9. The system of claim 1 :
wherein the plurality of factors includes a respective heat flow between the AC power bus and reference components for each of the multiple phases, the respective heat flow (Q ref ) being obtained as: Q ref =[T ref −T ACBB ]*K ref ; and
wherein T ref denotes a respective temperature of the reference components, T ACBB denotes the respective temperature of the plurality of busbars, and K ref denotes a respective thermal conductivity of the reference components.

10. The system of claim 9 , wherein the reference components include the stator, the power inverter module, the motor oil, the inverter coolant, and a common-mode choke in thermal communication with the plurality of busbars.

11. The system of claim 1 , wherein the plurality of factors includes respective electrical losses of the plurality of busbars, the respective electrical losses (P loss ) being based in part on a speed (N Mtr ) of the electric motor in RPM, and a calibratable speed threshold (N Thrs ) for determining if the electric motor is in a stall operation.

12. The system of claim 11 , wherein the respective electrical losses are based on a root-mean-square current (I RMS ) when the electric motor is in a non-stall operation and individual phase currents (I abc ) when the electric motor is in the stall operation.

13. A method of operating a vehicle having a power inverter module, an electric motor configured to generate torque, and a controller having a processor and tangible, non-transitory memory, the method comprising:
coupling an alternating current (AC) power bus to the power inverter module, the AC power bus having a plurality of busbars for conducting an AC current having multiple phases;
coupling the AC power bus to a stator in the electric motor;
positioning the plurality of busbars to be in respective thermal contact with an inverter coolant and motor oil;
determining an estimated temperature of the AC power bus for each of the multiple phases of the AC current based on a plurality of factors, the plurality of factors including an oil flow rate of the motor oil and a coolant flow rate of the inverter coolant; and
controlling operation of the vehicle based in part on a highest one of the estimated temperature for the multiple phases.

14. The method of claim 13 , further comprising:
determining an inverter capability based in part on the temperature estimate, wherein controlling operation of the vehicle includes derating of the torque based in part on the inverter capability.

15. The method of claim 13 , further comprising:
incorporating a secondary source in the vehicle for sele

Assignees

• Gm Global Tech Operations Llc

Inventors

• Berry Daniel J
• Kim Young J
• Day Dylan M
• Yambor Jeffrey W

Classifications

• B60L2240/80

  Time limits · CPC title

• B60L2260/44

  by parameter estimation · CPC title

• B60L3/12

  Recording operating variables {; Monitoring of operating variables} · CPC title

• B60L2240/36

  Temperature of vehicle components or parts · CPC title

• B60L15/007

  Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles · CPC title