Method for direct voltage saturation calculation and prevention of inverter voltage saturation

Patent metadata

Field	Value
Publication number	US-2020328710-A1
Application number	US-201916560657-A
Country	US
Kind code	A1
Filing date	Sep 4, 2019
Priority date	Apr 14, 2019
Publication date	Oct 15, 2020
Grant date	—

Abstract

A voltage saturation prevention algorithm used as at least part of a method of controlling an electric vehicle, wherein the electric vehicle comprises an electric motor, a controller, and an inverter. The controller receives a control signal with an instruction to operate the electric motor, then sends a switching signal corresponding to the control signal to the inverter, wherein the inverter provides a plurality of output signals for operation of the electric motor. The method includes determining the expected amplitude of the plurality of output signals based on the instruction to operate the electric motor, calculating the amount of modification of the plurality of output signals required to prevent the expected amplitude from reaching a saturation value, and modifying, based on the calculation, the instruction to operate the electric motor to prevent the expected amplitude from reaching the saturation value. The method is implemented in software, without any additional hardware.

First claim

What is claimed is:

1 . A method of controlling an electric vehicle comprising:
an electric motor, a controller, wherein the controller receives a control signal with an instruction to operate the electric motor, and an inverter that receives a switching signal corresponding to the control signal from the controller, the inverter providing a plurality of output signals for operation of the electric motor; and wherein the method includes: determining the expected amplitude of the plurality of output signals based on the instruction to operate the electric motor, calculating the amount of modification of the plurality of output signals required to prevent the expected amplitude from reaching a saturation value, and modifying, based on the calculation, the instruction to operate the electric motor to prevent the expected amplitude from reaching the saturation value.

2 . The method of claim 1 , wherein the method is implemented in software.

3 . The method of claim 1 , wherein the instruction is an instruction for the inverter to operate at a specific command current value.

4 . The method of claim 3 , wherein the specific command current value has a plurality of current components.

5 . The method of claim 1 , wherein the plurality of output signals is a plurality of voltage components.

6 . The method of claim 1 , wherein calculating is based on current angle modification.

7 . The method of claim 6 , wherein a modification in current angle results in reduction of voltage amplitude.

8 . The method of claim 1 , wherein the method automatically corrects the errors in a calibration table of the electric motor.

9 . An electric vehicle comprising:
an electric motor, a controller, wherein the controller receives a control signal with an instruction to operate the electric motor, and an inverter that receives a switching signal corresponding to the control signal from the controller, the inverter providing a plurality of output signals for operation of the electric motor; wherein the electric vehicle is controlled by a method including: determining the expected amplitude of the plurality of output signals based on the instruction to operate the electric motor, calculating the amount of modification of the plurality of output signals required to prevent the expected amplitude from reaching a saturation value, and modifying, based on the calculation, the instruction to operate the electric motor to prevent the expected amplitude from reaching the saturation value.

10 . The electric vehicle of claim 9 , wherein the method is implemented in software.

11 . The electric vehicle of claim 9 , wherein the instruction is an instruction for the inverter to operate at a specific command current value.

12 . The electric vehicle of claim 11 , wherein the specific command current value has a plurality of current components.

13 . The electric vehicle of claim 9 , wherein the plurality of output signals is a plurality of voltage components.

14 . The electric vehicle of claim 9 , wherein calculating is based on current angle modification.

15 . The electric vehicle of claim 14 , wherein a modification in current angle results in reduction of voltage amplitude.

16 . The electric vehicle of claim 9 , wherein the method automatically corrects the errors in a calibration table of the electric motor.

Assignees

• Karma Automtoive Llc
• Karma Automotive Llc

Inventors

• Ziaieinejad Saleh
• Niu Geng

Classifications

• Y02T10/64

  Electric machine technologies in electromobility · CPC title

• B60L3/003

  relating to inverters · CPC title

• B60L15/20

  for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed · CPC title

• Y02T10/72

  Electric energy management in electromobility · CPC title

• H02P27/08

  with pulse width modulation · CPC title