US-12617303-B2 - Vehicular electric drive system including traction battery, inverter, and motor having self-heater arrangement

Abstract

A system for an electrified vehicle, such as a battery electric vehicle (BEV), includes an inverter connected between a battery and a motor having windings. A center-tap of the battery and a neutral-point of the windings are connected whereby the battery, the inverter, and the motor are connected in a closed circuit. The system further includes a controller configured to control the inverter to cause a circulating current from the battery through the closed circuit to thereby achieve a target temperature of the battery.

Inventors

• BAOMING GE
• Petros G. Taskas

Assignees

• FORD GLOBAL TECHNOLOGIES, LLC

Dates

Publication Date

20260505

Application Date

20230725

Claims (18)

1. 1 . A system comprising: an inverter connected between a battery and a motor, the motor having first, second, and third windings, each winding having an input end and an output end, the output ends of the windings being connected at a neutral-point of the windings, the inverter having a first phase that is connected to the input end of the first winding, a second phase that is connected to the input end of the second winding, and a third phase that is connected to the input end of the third winding, wherein each phase has a top power switch and a bottom power switch; a conductor connecting a center-tap of the battery and the neutral-point of the windings whereby the battery, the first, second, and third phases of the inverter, and the motor are connected in a closed circuit via the conductor; and a controller configured to switch on-and-off the top power switches of the first, second, and third phases of the inverter pursuant to a selected switching frequency while switching off the bottom power switches of the first, second, and third phases pursuant to a selected duty cycle during a first half-cycle of a circulating current and switch on-and-off the bottom power switches of the first, second, and third phases pursuant to the selected switching frequency while switching off the top power switches of the first, second, and third phases pursuant to the selected duty cycle during a second half-cycle of the circulating current such that, during each half-cycle, only one of the top power switches or the bottom power switches of each phase is actively switched while the other is held continuously in a non-conductive state for the entirety of the half-cycle to cause a circulating current, comprising successive alternating half-cycles and in a form of an alternating current (AC) square wave, from the battery through the closed circuit to thereby achieve a target temperature of the battery.
2. 2 . The system of claim 1 wherein: the controller is further configured to control the selected switching frequency to control an amplitude of the circulating current.
3. 3 . The system of claim 1 wherein: the controller is further configured to control a period of the selected duty cycle to control a frequency of the circulating current.
4. 4 . The system of claim 1 wherein: the conductor has a switch movable between an opened position and a closed position; wherein the center-tap of the battery and the neutral-point of the windings are connected via the conductor when the switch is closed; and the center-tap of the battery and the neutral-point of the windings are disconnected when the switch is opened.
5. 5 . The system of claim 4 wherein: the controller is configured to move the switch between the opened position and the closed position.
6. 6 . The system of claim 4 wherein: the inverter is configured to drive the motor with electrical power from the battery while the switch is in the opened position.
7. 7 . The system of claim 4 wherein: the inverter is configured to supply the battery with electrical power received via the motor while the switch is in the opened position.
8. 8 . The system of claim 1 wherein: the battery includes a top battery bank and a bottom battery bank; and a cathode of the top battery pack and an anode of the bottom battery pack are connected together at the center-tap of the battery.
9. 9 . The system of claim 8 wherein: a voltage of the top battery bank and a voltage of the bottom battery bank are substantially the same.
10. 10 . A method for use with an electric drive system of a vehicle, the electric drive system having a traction battery, a motor having first, second, and third motor windings, each motor winding having an input end and an output end, the output ends of the motor windings being connected at a neutral-point of the windings, and an inverter connected between the traction battery and the motor, the inverter having a first phase that is connected to the input end of the first motor winding, a second phase that is connected to the input end of the second motor winding, and a third phase that is connected to the input end of the third motor winding, wherein each phase has a top power switch and a bottom power switch, the method comprising: connecting with a conductor a center-tap of the traction battery and the neutral-point of the motor windings together whereby the traction battery, the first, second, and third phases of the inverter, and the motor are connected in a closed circuit via the conductor; and switching on-and-off the top power switches of the first, second, and third phases of the inverter pursuant to a selected switching frequency while switching off the bottom power switches of the first, second, and third phases pursuant to a selected duty cycle during a first half-cycle of a circulating current and switching on-and-off the bottom power switches of the first, second, and third phases pursuant to the selected switching frequency while switching off the top power switches of the first, second, and third phases pursuant to the selected duty cycle during a second half-cycle of the circulating current such that, during each half-cycle, only one of the top power switches or the bottom power switches of each phase is actively switched while the other is held continuously in a non-conductive state for the entirety of the half-cycle to cause a circulating current, comprising successive alternating half-cycles and in a form of an alternating current (AC) square wave, from the traction battery through the closed circuit to thereby achieve a target temperature of the traction battery.
11. 11 . The method of claim 10 further comprising: controlling the selected switching frequency to control an amplitude of the circulating current.
12. 12 . The method of claim 10 further comprising: controlling a period of the selected duty cycle to control a frequency of the circulating current.
13. 13 . The method of claim 10 wherein: connecting the center-tap of the traction battery and the neutral-point of the motor windings together is performed only while the vehicle is not being propelled by the motor and the target temperature of the traction battery is not achieved.
14. 14 . The method of claim 10 further comprising: subsequently disconnecting the center-tap of the traction battery and the neutral-point of the motor windings from one another while the vehicle is to be propelled by the motor; and controlling the inverter to drive the motor with electrical power from the traction battery for the motor to propel the vehicle.
15. 15 . An electric drive system for a vehicle, the electric drive system comprising: a traction battery; a motor having first, second and third motor windings, each motor winding having an input end and an output end, the output ends of the motor windings being connected at a neutral-point of the windings; an inverter connected between the traction battery and the motor, the inverter having a first phase that is connected to the input end of the first motor winding, a second phase that is connected to the input end of the second motor winding, and a third phase that is connected to the input end of the third motor winding, wherein each phase has a top power switch and a bottom power switch; a conductor having a switch movable between an opened position and a closed position; wherein a center-tap of the traction battery and the neutral-point of the motor windings are connected together via the conductor when the switch is in the closed position whereby the traction battery, the first, second, and third phases of the inverter, and the motor are connected in a closed circuit via the conductor when the switch is in the closed position; and a controller configured to switch on-and-off the top power switches of the first, second, and third phases of the inverter pursuant to a selected switching frequency while switching off the bottom power switches of the first, second, and third phases pursuant to a selected duty cycle during a first half-cycle of a circulating current and switch on-and-off the bottom power switches of the first, second, and third phases pursuant to the selected switching frequency while switching off the top power switches of the first, second, and third phases pursuant to the selected duty cycle during a second half-cycle of the circulating current such that, during each half-cycle, only one of the top power switches or the bottom power switches of each phase is actively switched while the other is held continuously in a non-conductive state for the entirety of the half-cycle when the switch is in the closed position to cause a circulating current, in a form of an alternating current (AC) square wave, from the traction battery through the closed circuit to thereby generate heat for warming the traction battery and transmission fluid of the motor.
16. 16 . The electric drive system of claim 15 wherein: the controller is further configured to control the selected switching frequency to control an amplitude of the circulating current and/or control a period of the selected duty cycle to control a frequency of the circulating current.
17. 17 . The electric drive system of claim 15 wherein: the controller is configured to move the switch to the closed position while the vehicle is not being propelled by the motor and a target temperature of the traction battery and the motor windings is not achieved.
18. 18 . The electric drive system of claim 15 wherein: the controller is configured to move the switch to the opened position while the vehicle is to be propelled by the motor and the controller is further configured to control the inverter to drive the motor with electrical power from the traction battery for the motor to propel the vehicle.

Description

TECHNICAL FIELD The present disclosure relates to utilizing a traction battery, an inverter, and windings of a motor of an electric drive system of an electrified vehicle to heat the traction battery and transmission fluid of the motor. BACKGROUND An electrified vehicle includes an electric drive system having a traction battery, an inverter, and a motor. The motor is powered with electrical energy from the traction battery via the inverter to propel the electrified vehicle. SUMMARY A system having an inverter and a controller is provided. The inverter is connected between a battery and a motor having windings. A center-tap of the battery and a neutral-point of the windings are connected whereby the battery, the inverter, and the motor are connected in a closed circuit. The controller is configured to control the inverter to cause a circulating current from the battery through the closed circuit to thereby achieve a target temperature of the battery. The controller may control the inverter to control an amplitude and/or a frequency of the circulating current. The circulating current may be an alternating current (AC) square wave. The system may further include a conductor having a switch movable between an opened position and a closed position. The center-tap of the battery and the neutral-point of the windings are connected via the conductor when the switch is closed. The center-tap of the battery and the neutral-point of the windings are disconnected when the switch is opened. The controller may move the switch between the opened position and the closed position. The inverter may drive the motor with electrical power from the battery while the switch is in the opened position. The inverter may supply the battery with electrical power received via the motor while the switch is in the opened position. The battery may include a top battery bank and a bottom battery bank with a cathode of the top battery pack and an anode of the bottom battery pack being connected together at the center-tap of the battery. A voltage of the top battery bank and a voltage of the bottom battery bank may be substantially the same. A method for use with an electric drive system (EDS) of a vehicle is provided. The EDS has a traction battery, a motor having a plurality of motor windings, and an inverter connected between the traction battery and the motor. The method includes connecting a center-tap of the traction battery and a neutral-point of the motor windings together whereby the battery, the inverter, and the motor are connected in a closed circuit. The method further includes controlling the inverter to cause a circulating current from the traction battery through the closed circuit to thereby achieve a target temperature of the traction battery. The step of connecting the center-tap of the traction battery and the neutral-point of the motor windings together may be only performed while the vehicle is not being propelled by the motor and the target temperature of the traction battery is not achieved. The method may further include disconnecting the center-tap of the traction battery and the neutral-point of the motor windings from one another while the vehicle is to be propelled by the motor and controlling the inverter to drive the motor with electrical power from the traction battery for the motor to propel the vehicle. An EDS of a vehicle in which the EDS has a traction battery, a motor having a plurality of motor windings, and an inverter connected between the battery and the motor is provided. The EDS further has a conductor having a switch movable between an opened position and a closed position. A center-tap of the traction battery and a neutral-point of the motor windings are connected together via the conductor when the switch is in the closed position whereby the traction battery, the inverter, and the motor are connected in a closed circuit when the switch is in the closed position. A controller associated with the EDS is configured to control the inverter when the switch is in the closed position to cause a circulating current from the traction battery through the closed circuit to thereby generate heat for warming the traction battery and transmission fluid of the motor. The controller may move the switch to the closed position while the vehicle is not being propelled by the motor and a target temperature of the traction battery and the motor windings is not achieved. The controller may move the switch to the opened position while the vehicle is to be propelled by the motor and may control the inverter to drive the motor with electrical power from the traction battery for the motor to propel the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a block diagram of a battery electric vehicle (BEV) having an electric drive system (EDS) including a traction battery, an inverter, and a motor; FIG. 2 illustrates a functional diagram of the traction battery, the inverter, and the motor of the EDS and a contr