Optimization of switching frequency and pulse width modulation technique for traction power inverters

Patent metadata

Field	Value
Publication number	US-12459376-B2
Application number	US-202318376599-A
Country	US
Kind code	B2
Filing date	Oct 4, 2023
Priority date	Oct 4, 2023
Publication date	Nov 4, 2025
Grant date	Nov 4, 2025

Abstract

A method of operating a power inverter for an electric machine includes selecting an inverter switching technique; determining a frequency range for inverter switching; determining a direct current (DC) voltage range for inverter switching; determining an optimal switching map including an inverter switching technique and frequency selection for each value of torque-speed on a torque-speed curve; and controlling switches included in the power inverter using the optimal switching map.

First claim

What is claimed is:

1 . A method of operating a power inverter for an electric machine, comprising the steps of:
(a) selecting an inverter switching technique; (b) determining a frequency range for inverter switching; (c) determining a direct current (DC) voltage range for inverter switching; (d) determining a maximum efficiency at each torque-speed value along the torque-speed curve based on an alternating current (AC) ripple; (e) determining an optimal switching map including an inverter switching technique and frequency selection for each value of torque-speed on a torque-speed curve; and (f) controlling switches included in the inverter using the optimal switching map.

2 . The method recited in claim 1 , further comprising the step of determining a maximum inverter efficiency at each torque-speed value along the torque-speed curve based on inverter switching technique and switching frequency.

3 . The method recited in claim 1 , further comprising the steps of determining an inverter power loss at a torque-speed value along a torque speed curve and determining a maximum inverter efficiency at each torque-speed value along the torque-speed curve based on inverter switching technique and switching frequency.

4 . The method recited in claim 1 , further comprising the step of determining whether a selected pulse ratio is greater than a pulse ratio maximum.

5 . The method recited in claim 1 , wherein the frequency range is from 2 kHz to 16 kHz.

6 . The method recited in claim 1 , further comprising the step of receiving a performance selection or an efficiency selection.

7 . The method recited in claim 1 , further comprising the step of propelling or regeneratively braking an electric vehicle using the controlled switches.

8 . A method of operating an inverter for an electric machine, comprising the steps of:
(a) selecting an inverter switching technique; (b) determining a frequency range for inverter switching; (c) determining a direct current (DC) voltage range for inverter switching; (d) measuring performance of the electric machine at a selected inverter switching technique and a determined frequency range; (e) determining an inverter power loss at a torque-speed value along a torque speed curve; (f) determining a maximum efficiency at each torque-speed value along the torque-speed curve based on inverter switching technique and switching frequency; (g) determining an optimal switching map including an inverter switching technique and frequency selection for each value of torque-speed on a torque-speed curve based on step (d); and (h) controlling switches included in the inverter using the optimal switching map.

9 . The method recited in claim 8 , further comprising the step of determining a maximum efficiency at each torque-speed value along the torque-speed curve based on inverter switching technique and switching frequency.

10 . The method recited in claim 8 , further comprising the step of determining a maximum efficiency at each torque-speed value along the torque-speed curve based on an alternating current (AC) ripple.

11 . The method recited in claim 8 , wherein the frequency range is from 2 kHz to 16 kHz.

12 . A power inverter for controlling an electric machine, comprising:
a control system configured to select an inverter switching technique; determine a frequency range for power inverter switching; determine a direct current (DC) voltage range for power inverter switching; determine a maximum efficiency at each torque-speed value along the torque-speed curve based on an alternating current (AC) ripple; determine an optimal switching map including an inverter switching technique and frequency selection for each value of torque-speed on a torque-speed curve; and control switches included in the power inverter that are configured to electrically connect to the electric machine and the battery using the optimal switching map.

13 . The power inverter recited in claim 12 , wherein the power inverter is configured to measure performance of the electric machine at a selected inverter switching technique and a determined frequency range.

14 . The power inverter recited in claim 12 , wherein the power inverter is configured to determine a maximum efficiency at each torque-speed value along the torque-speed curve based on inverter switching technique and switching frequency.

15 . The power inverter recited in claim 12 , wherein the power inverter is configured to determine an inverter power loss at a torque-speed value along a torque speed curve and determine a maximum efficiency at each torque-speed value along the torque-speed curve based on inverter switching technique and switching frequency.

16 . The power inverter recited in claim 12 , wherein the power inverter is configured to determine a maximum efficiency at each torque-speed value along the torque-speed curve based on an alternating current (AC) ripple.

Assignees

• Borgwarner Inc

Inventors

• Eldeeb Hassan H
• Kumar Ujjwal
• Krefta Ronald J
• Secrest Caleb W

Classifications

• B60L15/04

  using DC · CPC title

• B60L2240/423

  Torque · CPC title

• H02M7/5395

  by pulse-width modulation · CPC title

• H02M1/0058

  by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero (using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826) · CPC title

• B60L2210/42

  Voltage source inverters · CPC title