CN-122001268-A - Improved electric vehicle traction inverter efficiency

CN122001268ACN 122001268 ACN122001268 ACN 122001268ACN-122001268-A

Abstract

Improved electric vehicle traction inverter efficiency is provided. A vehicle propulsion system includes a system controller for determining a rotational speed and a rotational torque in response to a user input and a vehicle operating mode, a battery for supplying a DC current, a motor configured to generate the rotational torque at the rotational speed in response to an AC voltage, an inverter for converting the DC current to an AC current using a first transistor and a second transistor, and an inverter controller for determining a dead time in response to the rotational torque and the rotational speed and for removing a first switch control signal from the first transistor, waiting a duration equal to the dead time, and applying a second switch control signal to the second switch transistor, and wherein the dead time is continuously updated in response to a change in torque and a change in rotational speed.

Inventors

R. Amorim Torres
C.S. Namoduri
LUO YILUN

Assignees

通用汽车环球科技运作有限责任公司

Dates

Publication Date: 20260508
Application Date: 20241217
Priority Date: 20241101

Claims (10)

1. An inverter controller for an electric motor, comprising: A system controller for determining a rotational torque and a rotational speed of the motor; the motor for generating the rotational torque at the rotational speed in response to an AC voltage; a battery for supplying a DC voltage; an inverter including a first transistor and a second transistor for converting the DC voltage into the AC voltage, and An inverter controller for determining a dead time in response to the rotational torque and the rotational speed, and for removing a first switch control signal from the first transistor, waiting for a duration equal to the dead time, and applying a second switch control signal to the second transistor, and wherein the dead time is continuously updated in response to a change in the rotational torque and a change in the rotational speed.
2. The inverter controller for an electric motor of claim 1, further comprising a temperature sensor for detecting a first temperature of the first transistor and a second temperature of the second transistor, and wherein the dead time is determined in response to the first temperature and the second temperature.
3. The inverter controller for an electric motor of claim 1, wherein the inverter controller is configured to adjust the dead time by adjusting slew rates of the first and second switch control signals.
4. The inverter controller for an electric motor of claim 3, wherein the slew rate is increased in response to a decrease in battery voltage.
5. The inverter controller for an electric motor of claim 1, wherein the inverter controller is configured to adjust the dead time in response to at least one of a vehicle speed, a throttle position, a steering angle, and a battery voltage.
6. The inverter controller for an electric motor of claim 1, wherein the inverter controller is configured to adjust the dead time in response to at least one of inverter output current amplitude, junction temperature, and power module temperature.
7. The inverter controller for an electric motor of claim 1, wherein the inverter controller is configured to adjust the dead time in accordance with a set of gate driver parameters of at least one of the first transistor and the second transistor.
8. The inverter controller for the electric motor of claim 1, wherein the inverter controller is configured to decrease the dead time in response to at least one of a decreased inverter current and a decreased bus voltage, and to increase the dead time in response to at least one of an increased inverter current and an increased bus voltage.
9. The inverter controller for the motor according to claim 1, wherein the inverter controller is configured to adjust the dead time in response to a switching frequency of an inverter or a fundamental frequency of the motor.
10. A method of controlling a switching inverter of an electric motor for a vehicle application, comprising: Determining, by a system controller, a rotational torque and a rotational speed of the motor; generating, by the motor, the rotational torque at the rotational speed in response to an AC voltage; Supplying a DC voltage by a battery; converting the DC voltage into the AC voltage by an inverter including a first transistor and a second transistor, and A dead time is determined by an inverter controller in response to the rotational torque and the rotational speed and is used to remove a first switch control signal from the first transistor, wait for a duration equal to the dead time, and apply a second switch control signal to the second transistor, and wherein the dead time is continuously updated in response to a change in the rotational torque and a change in the rotational speed.

Description

Improved electric vehicle traction inverter efficiency Technical Field The present disclosure relates generally to electric vehicle motors and battery systems, and more particularly to a method and apparatus for utilizing adjustable dead time in a traction inverter to minimize conduction losses while preventing any shoot-through in the inverter phase legs by utilizing power devices with minimal switching time and gate charge to achieve shorter dead time. Background Electric Vehicles (EVs) use electric motors to convert electrical energy from a battery into mechanical energy to turn wheels. Generally, motors used in EVs are mainly of two types, induction motors and Permanent Magnet Synchronous Motors (PMSMs). Modern EVs typically have two motors, one for each axle, but some EVs may have a single motor located under the hood, or four motors, one for each wheel. EV motors are typically driven by three-phase Alternating Current (AC) currents. Since EV batteries supply Direct Current (DC) voltage, the DC voltage must be converted to three-phase AC. The conversion is performed by an inverter. The inverter acts as a power electronic interface between the battery and the motor, converting DC power stored in the battery to AC power that meets motor requirements. By precisely adjusting the voltage and frequency of the AC output, the inverter is able to precisely control the speed and torque of the motor. Such control is critical to achieving optimal vehicle performance, efficiency and responsiveness. The inverter typically employs switching transistors that are turned on and off at regular intervals to convert a DC voltage into three AC voltages, where each AC voltage is supplied to a different winding of the AC motor. To prevent a short circuit from occurring in the inverter when a plurality of transistors are simultaneously turned on, an intentional interval is introduced between turning off one transistor and before turning on the other transistor. This time interval is commonly referred to as dead time. Although dead time is critical to safety, dead time can also lead to inefficiency due to increased conduction losses across the freewheeling diode during this period. In order to provide systems and methods for vehicle propulsion and driver assistance systems, it is desirable to provide for employing inverter dead time as efficiently as possible to reduce any energy waste. Furthermore, other desirable features and characteristics of the present disclosure will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background. Disclosure of Invention Disclosed herein are vehicle control methods and systems and related electrical systems for providing a vehicle propulsion system, methods for manufacturing and methods for operating such systems, and motor vehicles and other devices, such as aircraft, trucks, buses, forklifts, construction vehicles, and other electric vehicles equipped with battery-powered motors. By way of example and not limitation, various embodiments of a system are presented to optimize the efficiency of a traction inverter by implementing adaptive dead time control, minimize conduction losses while ensuring zero shoot-through events, and achieve shorter dead times with power devices having fast switching characteristics and low gate charges. According to an exemplary embodiment of the present disclosure, an inverter controller for a motor includes a system controller to determine a rotational torque and a rotational speed of the motor, the motor to generate the rotational torque at the rotational speed in response to an AC voltage, a battery to supply a DC voltage, an inverter including a first transistor and a second transistor to convert the DC voltage to the AC voltage, and the inverter controller to determine a dead time in response to the rotational torque and the rotational speed and to remove a first switch control signal from the first transistor, wait for a duration equal to the dead time, and apply a second switch control signal to the second transistor, and wherein the dead time is continuously updated in response to a change in the rotational torque and a change in the rotational speed. According to another exemplary embodiment of the present disclosure, the method further comprises detecting a first temperature of the first transistor and a second temperature of the second transistor, and wherein the dead time is determined in response to the first temperature and the second temperature. According to another exemplary embodiment of the present disclosure, the inverter controller is configured to adjust the dead time by adjusting slew rates (slew rates) of the first and second switch control signals. According to another exemplary embodiment of the present disclosure, wherein the slew rate is increased in response to a decrease in the battery voltage. According to anot