阅读说明：本技术 能量转换装置的控制方法、装置及车辆 (Control method and device of energy conversion device and vehicle ) 是由 凌和平 潘华 谢飞跃 史建勇 赵婷婷 于 2020-06-04 设计创作，主要内容包括：本公开涉及一种能量转换装置的控制方法、装置及车辆,包括：获取车辆状态；在车辆状态为预设状态的情况下,控制三相逆变器中的第一桥臂和第二桥臂的通断,使电池与储能元件之间进行充电和放电,以实现电池的自加热,在加热期间,通过控制第一桥臂、第二桥臂使第一电机绕组和第二电机绕组中通过的电流值满足预设条件,以使电机产生的扭矩为零,其中,第三桥臂处于关断状态,第三电机绕组上的电流为零。这样能够通过控制第一桥臂和第二桥臂,来使与之连接的第一电机绕组和该第二电机绕组中通过的电流值满足预设条件,从而来控制该能量转换装置中的电机产生的扭矩为零,避免了电机脉动扭矩的出现,进而避免影响电机的寿命,且保证了车辆安全。(The present disclosure relates to a control method, a device and a vehicle of an energy conversion device, including: acquiring a vehicle state; and during heating, the first bridge arm and the second bridge arm are controlled to enable the current values passing through the first motor winding and the second motor winding to meet a preset condition so as to enable the torque generated by the motor to be zero, wherein the third bridge arm is in a turn-off state, and the current on the third motor winding is zero. Therefore, the current values passing through the first motor winding and the second motor winding connected with the first bridge arm and the second bridge arm can meet the preset conditions by controlling the first bridge arm and the second bridge arm, so that the torque generated by the motor in the energy conversion device is controlled to be zero, the occurrence of motor pulsation torque is avoided, the service life of the motor is further prevented from being influenced, and the safety of a vehicle is ensured.)

1. A control method of an energy conversion apparatus, characterized in that the energy conversion apparatus includes:

the three-phase inverter comprises a first bridge arm, a second bridge arm and a third bridge arm, and the motor comprises a first motor winding, a second motor winding and a third motor winding;

the method comprises the following steps:

acquiring a vehicle state;

and controlling the on-off of the first bridge arm and the second bridge arm in the three-phase inverter under the condition that the vehicle state is a preset state, so that the battery and the energy storage element are charged and discharged, and the self-heating of the battery is realized.

2. The method of claim 1, wherein the controlling the first bridge arm and the second bridge arm to enable the current value passing through the first motor winding and the second motor winding to meet a preset condition so that the torque generated by the motor is zero comprises:

and respectively controlling the duty ratio of the first bridge arm and the duty ratio of the second bridge arm to enable the current values passing through the first motor winding and the second motor winding to meet the preset condition so as to enable the torque generated by the motor to be zero.

3. The method according to claim 1 or 2, wherein the preset condition is that the following formula is satisfied:

i₁+i₂＝i_m，

wherein, the i₁For a target current value on the first motor winding, i₂Is a target current value on the second motor winding, theta is the rotor angle of the motor, i_mAnd the current value of the N line of the motor is obtained.

4. The method of claim 3, wherein the controlling the first bridge arm and the second bridge arm to enable the current value passing through the first motor winding and the second motor winding to meet a preset condition so that the torque generated by the motor is zero comprises:

and respectively acquiring target duty ratios corresponding to a first bridge arm and a second bridge arm according to the corresponding relation between the target current value flowing through the first motor winding and the duty ratio and the corresponding relation between the target current value flowing through the second motor winding and the duty ratio, and respectively controlling the on-off of the first bridge arm and the second bridge arm based on the target duty ratios so as to enable the torque generated by the motor to be zero.

5. The method of claim 1,

first ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a first bus end, the first bus end is connected with a positive electrode of the battery, second ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a second bus end, the second bus end is connected with a negative electrode of the battery, first ends of the first motor winding, the second motor winding and the third motor winding are respectively connected to middle points of the first bridge arm, the second bridge arm and the third bridge arm in a one-to-one correspondence manner, second ends of the first motor winding, the second motor winding and the third motor winding are connected to a first end of the energy storage element, and a second end of the energy storage element is connected to the second bus end;

in the preset state, the battery, the first bridge arm, the second bridge arm, the first motor winding, the second motor winding and the energy storage element form a battery heating circuit;

and during heating, controlling the duty ratios of the first bridge arm and the second bridge arm to enable the current values passing through the first motor winding and the second motor winding simultaneously to meet the preset condition so as to enable the torque generated by the motor to be zero.

6. The method of claim 1,

first ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a first bus end, the first bus end is connected with a first end of the energy storage element, second ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a second bus end, the second bus end is connected with a second end of the energy storage element, first ends of the first motor winding, the second motor winding and the third motor winding are respectively connected to middle points of the first bridge arm, the second bridge arm and the third bridge arm in a one-to-one correspondence manner, second ends of the first motor winding, the second motor winding and the third motor winding are connected to a positive electrode of the battery, and a negative electrode of the battery is connected to the second bus end;

in the preset state, the battery, the first bridge arm, the second bridge arm, the first motor winding, the second motor winding and the energy storage element form a battery heating circuit;

and during heating, controlling the duty ratios of the first bridge arm and the second bridge arm to enable the current values passing through the first motor winding and the second motor winding simultaneously to meet the preset condition so as to enable the torque generated by the motor to be zero.

7. The method of claim 1, wherein the controlling the first leg and the second leg of the three-phase inverter to charge and discharge the battery and the energy storage element comprises:

and controlling the upper bridge arms of the first bridge arm and the second bridge arm to be simultaneously conducted or controlling the lower bridge arms of the first bridge arm and the second bridge arm to be simultaneously conducted so as to charge or discharge the battery and the energy storage element.

8. The method of claim 3, wherein the first leg and the second leg are any two-phase legs of the three-phase inverter.

9. The method of claim 3, wherein the electric machine is a drive motor of a vehicle, and the first, second, and third motor windings are motor windings of the drive motor.

10. The method of claim 3, wherein the energy storage element is a capacitor.

11. A control device of an energy conversion device, characterized in that the energy conversion device comprises:

the three-phase inverter comprises a first bridge arm, a second bridge arm and a third bridge arm, wherein the motor comprises a first motor winding, a second motor winding and a third motor winding;

the control device includes:

an acquisition module configured to acquire a vehicle state;

the control module is configured to control on and off of the first bridge arm and the second bridge arm in the three-phase inverter to enable the battery and the energy storage element to be charged and discharged so as to achieve self-heating of the battery when the vehicle state is a preset state, and during heating, current values passing through the first motor winding and the second motor winding meet preset conditions by controlling the first bridge arm and the second bridge arm so as to enable torque generated by the motor to be zero, wherein the third bridge arm is in an off state, and current on the third motor winding is zero.

12. The apparatus of claim 11, wherein the control module is further configured to: and respectively controlling the duty ratio of the first bridge arm and the duty ratio of the second bridge arm to enable the current values passing through the first motor winding and the second motor winding to meet the preset condition so as to enable the torque generated by the motor to be zero.

13. The apparatus according to claim 11 or 12, wherein the preset condition is that the following formula is satisfied:

i₁+i₂＝i_m，

wherein, the i₁For a target current value on the first motor winding, i₂Is a target current value on the second motor winding, theta is the rotor angle of the motor, i_{Charging device}And the current value of the N line of the motor is obtained.

14. The apparatus of claim 13, wherein the control module is further configured to: and respectively acquiring target duty ratios corresponding to a first bridge arm and a second bridge arm according to the corresponding relation between the target current value flowing through the first motor winding and the duty ratio and the corresponding relation between the target current value flowing through the second motor winding and the duty ratio, and respectively controlling the on-off of the first bridge arm and the second bridge arm based on the target duty ratios so as to enable the torque generated by the motor to be zero.

15. The apparatus of claim 11,

first ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a first bus end, the first bus end is connected with a positive electrode of the battery, second ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a second bus end, the second bus end is connected with a negative electrode of the battery, first ends of the first motor winding, the second motor winding and the third motor winding are respectively connected to middle points of the first bridge arm, the second bridge arm and the third bridge arm in a one-to-one correspondence manner, second ends of the first motor winding, the second motor winding and the third motor winding are connected to a first end of the energy storage element, and a second end of the energy storage element is connected to the second bus end;

in the preset state, the battery, the first bridge arm, the second bridge arm, the first motor winding, the second motor winding and the energy storage element form a battery heating circuit;

the control module is further configured to: and during heating, controlling the duty ratios of the first bridge arm and the second bridge arm to enable the current values passing through the first motor winding and the second motor winding simultaneously to meet the preset condition so as to enable the torque generated by the motor to be zero.

16. The apparatus of claim 11,

first ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a first bus end, the first bus end is connected with a first end of the energy storage element, second ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a second bus end, the second bus end is connected with a second end of the energy storage element, first ends of the first motor winding, the second motor winding and the third motor winding are respectively connected to middle points of the first bridge arm, the second bridge arm and the third bridge arm in a one-to-one correspondence manner, second ends of the first motor winding, the second motor winding and the third motor winding are connected to a positive electrode of the battery, and a negative electrode of the battery is connected to the second bus end;

in the preset state, the battery, the first bridge arm, the second bridge arm, the first motor winding, the second motor winding and the energy storage element form a battery heating circuit;

the control module is further configured to: and during heating, controlling the duty ratios of the first bridge arm and the second bridge arm to enable the current values passing through the first motor winding and the second motor winding simultaneously to meet the preset condition so as to enable the torque generated by the motor to be zero.

17. The apparatus of claim 11, wherein the control module is further configured to: and controlling the upper bridge arms of the first bridge arm and the second bridge arm to be simultaneously conducted or controlling the lower bridge arms of the first bridge arm and the second bridge arm to be simultaneously conducted so as to charge or discharge the battery and the energy storage element.

18. The apparatus of claim 11, wherein the first leg and the second leg are any two-phase legs of the three-phase inverter.

19. The apparatus of claim 11, wherein the motor is a drive motor of a vehicle, and the first motor winding, the second motor winding, and the third motor winding are motor windings of the drive motor.

20. The device of claim 11, wherein the energy storage element is a capacitor.

21. A vehicle characterized by comprising a control device of the energy conversion device according to any one of claims 11 to 20.

Technical Field

The disclosure relates to the field of vehicles, in particular to a control method and device of an energy conversion device and a vehicle.

Background

With the wide use of new energy, batteries can be used as a power source in various fields. The battery may be used as a power source in different environments, and the performance of the battery may be affected. For example, the performance of the battery in a low-temperature environment is greatly reduced from that at normal temperature. For example, the discharge capacity of the battery at the zero point temperature may decrease as the temperature decreases. At-30 ℃, the discharge capacity of the battery was substantially 0, resulting in the battery being unusable. In order to use the battery in a low-temperature environment, the battery needs to be heated. In the prior art, a method for heating a battery by using a heating structure built in a motor driving system is disclosed, in which a two-phase motor winding is used as an energy storage inductor, and the battery pack is heated by alternately charging and discharging the battery pack and the energy storage inductor, so as to achieve the purpose of heating the battery, as shown in fig. 1a and 1 b. Fig. 1a is a schematic diagram of an energy storage current loop in a process of heating a battery in the prior art, when the battery is in a discharging process, an upper bridge arm of a first bridge arm where a first transistor VT1 is located in a three-phase inverter 10 and a lower bridge arm of a second bridge arm where a sixth transistor VT6 is located are simultaneously turned on, a current starts from a positive electrode of the battery, flows through a first motor winding and a second motor winding in a motor 20 through the upper bridge arm where the first transistor VT1 is located, then flows back to a negative electrode of the battery after flowing through the lower bridge arm where the sixth transistor VT6 is located, a current value rises, and energy is stored in the first motor winding and the second motor winding in the motor; fig. 1b is a schematic diagram of a follow current loop in a process of heating a battery in the prior art, when the battery is in a charging process, an upper bridge arm of a second bridge arm where a third transistor VT3 is located and a lower bridge arm of a first bridge arm where a fourth transistor VT4 is located in a three-phase inverter 10 are simultaneously turned on, current returns to the battery from two discharged click windings after passing through the lower bridge arm where the fourth transistor VT4 is located and the upper bridge arm where the third transistor VT3 is located, and a current value decreases. The two processes are repeated, the battery is in a rapid charging and discharging alternating state, and due to the existence of the internal resistance of the battery, a large amount of heat is generated inside the battery, and the temperature is rapidly increased.

However, the prior art has the following problems: when the motor winding in the motor driving system has current, a current vector can be formed and a magnetic field is generated, so that a motor rotor can output pulsating torque, and the service life of the motor and the safety of a vehicle are greatly influenced.

Disclosure of Invention

The present disclosure is directed to a method and an apparatus for controlling an energy conversion apparatus, and a vehicle, which can control a torque generated by a motor in the energy conversion apparatus to be zero by controlling current values generated in two motor windings in the energy conversion apparatus when a current on a third motor winding is zero in a case where a battery is heated using two motor windings of the motor, thereby ensuring vehicle safety.

In order to achieve the above object, the present disclosure provides a control method of an energy conversion apparatus including:

the three-phase inverter comprises a first bridge arm, a second bridge arm and a third bridge arm, and the motor comprises a first motor winding, a second motor winding and a third motor winding;

the method comprises the following steps:

acquiring a vehicle state;

and controlling the on-off of the first bridge arm and the second bridge arm in the three-phase inverter under the condition that the vehicle state is a preset state, so that the battery and the energy storage element are charged and discharged, and the self-heating of the battery is realized.

Optionally, the controlling the first bridge arm and the second bridge arm to enable a value of a current passing through the first motor winding and the second motor winding to satisfy a preset condition so that a torque generated by the motor is zero includes:

and respectively controlling the duty ratio of the first bridge arm and the duty ratio of the second bridge arm to enable the current values passing through the first motor winding and the second motor winding to meet the preset condition so as to enable the torque generated by the motor to be zero.

Optionally, the preset condition is that the following formula is satisfied:

i₁+i₂＝i_m，

wherein, the i₁For a target current value on the first motor winding, i₂Is a target current value on the second motor winding, theta is the rotor angle of the motor, i_mThe current value of the N line of the motor is shown.

Optionally, the controlling the first bridge arm and the second bridge arm to enable a value of a current passing through the first motor winding and the second motor winding to satisfy a preset condition so that a torque generated by the motor is zero includes:

and respectively acquiring target duty ratios corresponding to a first bridge arm and a second bridge arm according to the corresponding relation between the target current value flowing through the first motor winding and the duty ratio and the corresponding relation between the target current value flowing through the second motor winding and the duty ratio, and respectively controlling the on-off of the first bridge arm and the second bridge arm based on the target duty ratios so as to enable the torque generated by the motor to be zero.

Optionally, first ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a first bus end, the first bus end is connected to a positive electrode of the battery, second ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a second bus end, the second bus end is connected to a negative electrode of the battery, first ends of the first motor winding, the second motor winding and the third motor winding are respectively connected to midpoints of the first bridge arm, the second bridge arm and the third bridge arm in a one-to-one correspondence manner, second ends of the first motor winding, the second motor winding and the third motor winding are connected to a first end of the energy storage element, and a second end of the energy storage element is connected to the second bus end;

in the preset state, the battery, the first bridge arm, the second bridge arm, the first motor winding, the second motor winding and the energy storage element form a battery heating circuit;

and during heating, controlling the duty ratios of the first bridge arm and the second bridge arm to enable the current values passing through the first motor winding and the second motor winding simultaneously to meet the preset condition so as to enable the torque generated by the motor to be zero.

Optionally, first ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a first bus end, the first bus end is connected to a first end of the energy storage element, second ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a second bus end, the second bus end is connected to a second end of the energy storage element, first ends of the first motor winding, the second motor winding and the third motor winding are respectively connected to midpoints of the first bridge arm, the second bridge arm and the third bridge arm in a one-to-one correspondence manner, second ends of the first motor winding, the second motor winding and the third motor winding are connected to a positive electrode of the battery, and a negative electrode of the battery is connected to the second bus end;

in the preset state, the battery, the first bridge arm, the second bridge arm, the first motor winding, the second motor winding and the energy storage element form a battery heating circuit;

and during heating, controlling the duty ratios of the first bridge arm and the second bridge arm to enable the current values passing through the first motor winding and the second motor winding simultaneously to meet the preset condition so as to enable the torque generated by the motor to be zero.

Optionally, the controlling the on/off of the first leg and the second leg of the three-phase inverter to charge and discharge the battery and the energy storage element includes:

and controlling the upper bridge arms of the first bridge arm and the second bridge arm to be simultaneously conducted or controlling the lower bridge arms of the first bridge arm and the second bridge arm to be simultaneously conducted so as to charge or discharge the battery and the energy storage element.

Optionally, the first leg and the second leg are any two-phase legs of the three-phase inverter.

Optionally, the motor is a driving motor of a vehicle, and the first motor winding, the second motor winding and the third motor winding are motor windings of the driving motor.

Optionally, the energy storage element is a capacitor.

The present disclosure also provides a control device of an energy conversion device, the energy conversion device including:

the three-phase inverter comprises a first bridge arm, a second bridge arm and a third bridge arm, wherein the motor comprises a first motor winding, a second motor winding and a third motor winding;

the control device includes:

an acquisition module configured to acquire a vehicle state;

the control module is configured to control on and off of the first bridge arm and the second bridge arm in the three-phase inverter to enable the battery and the energy storage element to be charged and discharged so as to achieve self-heating of the battery when the vehicle state is a preset state, and during heating, current values passing through the first motor winding and the second motor winding meet preset conditions by controlling the first bridge arm and the second bridge arm so as to enable torque generated by the motor to be zero, wherein the third bridge arm is in an off state, and current on the third motor winding is zero.

Optionally, the control module is further configured to: respectively controlling the duty ratio of the first bridge arm and the duty ratio of the second bridge arm to enable the current value passing through the first motor winding and the second motor winding to meet the preset condition so as to enable the torque generated by the motor to be zero

Optionally, the preset condition is that the following formula is satisfied:

i₁+i₂＝i_m，

wherein, the i₁For a target current value on the first motor winding, i₂Is a target current value on the second motor winding, theta is the rotor angle of the motor, i_mThe current value of the N line of the motor is shown.

Optionally, the control module is further configured to: and respectively acquiring target duty ratios corresponding to a first bridge arm and a second bridge arm according to the corresponding relation between the target current value flowing through the first motor winding and the duty ratio and the corresponding relation between the target current value flowing through the second motor winding and the duty ratio, and respectively controlling the on-off of the first bridge arm and the second bridge arm based on the target duty ratios so as to enable the torque generated by the motor to be zero.

Optionally, first ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a first bus end, the first bus end is connected to a positive electrode of the battery, second ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a second bus end, the second bus end is connected to a negative electrode of the battery, first ends of the first motor winding, the second motor winding and the third motor winding are respectively connected to midpoints of the first bridge arm, the second bridge arm and the third bridge arm in a one-to-one correspondence manner, second ends of the first motor winding, the second motor winding and the third motor winding are connected to a first end of the energy storage element, and a second end of the energy storage element is connected to the second bus end;

in the preset state, the battery, the first bridge arm, the second bridge arm, the first motor winding, the second motor winding and the energy storage element form a battery heating circuit;

the control module is further configured to: and during heating, controlling the duty ratios of the first bridge arm and the second bridge arm to enable the current values passing through the first motor winding and the second motor winding simultaneously to meet the preset condition so as to enable the torque generated by the motor to be zero.

Optionally, first ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a first bus end, the first bus end is connected to a first end of the energy storage element, second ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a second bus end, the second bus end is connected to a second end of the energy storage element, first ends of the first motor winding, the second motor winding and the third motor winding are respectively connected to midpoints of the first bridge arm, the second bridge arm and the third bridge arm in a one-to-one correspondence manner, second ends of the first motor winding, the second motor winding and the third motor winding are connected to a positive electrode of the battery, and a negative electrode of the battery is connected to the second bus end;

in the preset state, the battery, the first bridge arm, the second bridge arm, the first motor winding, the second motor winding and the energy storage element form a battery heating circuit;

the control module is further configured to: and during heating, controlling the duty ratios of the first bridge arm and the second bridge arm to enable the current values passing through the first motor winding and the second motor winding simultaneously to meet the preset condition so as to enable the torque generated by the motor to be zero.

Optionally, the control module is further configured to: and controlling the upper bridge arms of the first bridge arm and the second bridge arm to be simultaneously conducted or controlling the lower bridge arms of the first bridge arm and the second bridge arm to be simultaneously conducted so as to charge or discharge the battery and the energy storage element.

Optionally, the first leg and the second leg are any two-phase legs of the three-phase inverter.

Optionally, the motor is a driving motor of a vehicle, and the first motor winding, the second motor winding and the third motor winding are motor windings of the driving motor.

Optionally, the energy storage element is a capacitor.

The present disclosure also provides a vehicle including the control device of the above energy conversion device.

Through the technical scheme, under the condition that the battery is heated by using the two-phase motor winding of the motor, the current values passing through the first motor winding and the second motor winding can meet the preset condition by controlling the first bridge arm and the second bridge arm which are connected with the first motor winding and the second motor winding in the energy conversion device, so that the torque generated by the motor in the energy conversion device is controlled to be zero, the function of heating the battery can be realized by using the motor driving circuit, the motor can be prevented from outputting pulsating torque, the service life of the motor is prevented from being influenced, and the safety of a vehicle is ensured.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

fig. 1a is a schematic diagram of a storage current loop in a process of heating a battery in the prior art.

Fig. 1b is a schematic diagram of a freewheeling current loop during heating of a battery in the prior art.

Fig. 2 shows a schematic view of an energy conversion device.

Fig. 3 is a flowchart illustrating a control method of an energy conversion apparatus according to an exemplary embodiment of the present disclosure.

Fig. 4 shows a schematic diagram of a connection relationship between an energy conversion device and the vehicle battery.

Fig. 5 is a schematic diagram showing a connection relationship between still another energy conversion device and the vehicle battery.

Fig. 6 is a flowchart illustrating a control method of an energy conversion apparatus according to still another exemplary embodiment of the present disclosure.

Fig. 7 is a flowchart illustrating a control method of an energy conversion apparatus according to still another exemplary embodiment of the present disclosure.

Fig. 8a, 8b, 8c, 8d are schematic views showing current flows in four different states during the heating of the battery according to the connection relationship between an energy conversion device and the vehicle battery, respectively.

Fig. 9 is a block diagram illustrating a configuration of a control apparatus of an energy conversion apparatus according to an exemplary embodiment of the present disclosure.

Description of the reference numerals

100 energy conversion device 200 battery

10 three-phase inverter 20 motor

30 energy storage element VT 1-VT 6 power switch tube

Midpoint between A and F of VD 1-VD 6 follow current tube

300 control device 301 acquisition module of energy conversion device

302 control module

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

Fig. 2 shows a schematic view of an energy conversion device 100. As shown in fig. 2, the energy conversion apparatus includes: the three-phase inverter 10, the motor 20 and the energy storage element 30 are connected with a battery 2000 to form a battery heating circuit, wherein the three-phase inverter 10 comprises a first bridge arm, a second bridge arm and a third bridge arm, and the motor comprises a first motor winding, a second motor winding and a third motor winding.

Fig. 3 is a flowchart illustrating a control method of an energy conversion apparatus according to an exemplary embodiment of the present disclosure. As shown in fig. 3, the method includes step 301 and step 302.

In step 301, a vehicle state is acquired.

In step 302, when the vehicle state is a preset state, controlling on/off of the first bridge arm and the second bridge arm in the three-phase inverter to charge and discharge between the battery and the energy storage element so as to achieve self-heating of the battery, and during heating, controlling the first bridge arm and the second bridge arm to enable a current value passing through the first motor winding and the second motor winding to meet a preset condition so as to enable a torque generated by the motor to be zero, wherein the third bridge arm is in an off state, and a current on the third motor winding is zero.

The preset state may be, for example, a state in which the vehicle battery needs to be heated, wherein the preset state may include a state in which the vehicle is stationary and the vehicle battery needs to be heated, and may also include a state in which the vehicle battery is in a charging process and the vehicle battery needs to be heated.

In the case where the vehicle state is a preset state, the vehicle battery may be heated by controlling the energy conversion device as shown in fig. 2.

Here, the connection relationship between the energy conversion device 100 and the vehicle battery 200 may be two, as shown in fig. 4 and 5, respectively.

In a possible embodiment, the connection relationship between the energy conversion device 100 and the vehicle battery 200 can be as shown in fig. 4, wherein the three-phase inverter 10 includes power switching tubes VT 1-VT 6, follow current tubes VD 1-VD 6, switching tube VT1, follow current tube VD1, switching tube VT4, and follow current tube VD4 to form a phase bridge arm, switching tube VT3, follow current tube VD3, switching tube VT6, and follow current tube VD6 to form a phase bridge arm, switching tube VT5, follow current tube VD5, switching tube VT2, and follow current tube VD2 to form a phase bridge arm, the first ends of the first bridge arm, the second bridge arm, and the third bridge arm in the three-phase inverter 10 are connected together to form a first junction, the first bus end is connected to the positive pole of the battery 200, the second ends of the first bridge arm, the second bridge arm, and the third bridge arm are connected together to form a second junction, the negative pole of the battery 200 is connected to the second bridge arm, first ends of the first motor winding, the second motor winding and the third motor winding in the motor 20 are respectively connected to midpoints of the first bridge arm, the second bridge arm and the third bridge arm in a one-to-one correspondence manner, that is, a midpoint a, a midpoint B and a midpoint C shown in fig. 4, respectively, second ends of the first motor winding, the second motor winding and the third motor winding are connected to a first end of the energy storage element 30, and a second end of the energy storage element is connected to the second bus end.

When the vehicle state is the preset state, the battery 200, the first bridge arm, the second bridge arm, the first motor winding, the second motor winding, and the energy storage element 30 form a battery heating circuit. The first bridge arm and the second bridge arm are any two-phase bridge arm in the three-phase inverter 10, that is, the first bridge arm and the second bridge arm may be a bridge arm where the midpoint a is located and a bridge arm where the midpoint B is located, may also be a bridge arm where the midpoint a is located and a bridge arm where the midpoint C is located, and may also be a bridge arm where the midpoint B is located and a bridge arm where the midpoint C is located. Correspondingly, the first motor winding and the second motor winding may be any two motor windings in the motor 20, as long as the first motor winding and the second motor winding are correspondingly connected to the midpoint of the first bridge arm and the midpoint of the second bridge arm. In this embodiment, the three-phase inverter and motor of the battery heating circuit may multiplex the three-phase inverter and motor in the vehicle motor drive circuit, wherein the bus capacitors in the motor drive circuit are not shown in the figure.

In another possible embodiment, the connection relationship between the energy conversion device 100 and the vehicle battery 200 may be as shown in fig. 5, wherein the three-phase inverter 10 includes power switching tubes VT 1-VT 6, follow current tubes VD 1-VD 6, switching tube VT1, follow current tube VD1, switching tube VT4, and follow current tube VD4 to form a phase bridge arm, switching tube VT3, follow current tube VD3, switching tube VT6, and follow current tube VD6 to form a phase bridge arm, switching tube VT5, follow current tube VD5, switching tube VT2, and follow current tube VD2 to form a phase bridge arm, the first ends of the first bridge arm, the second bridge arm, and the third bridge arm in the three-phase inverter 10 are connected together to form a first junction, the first bus end is connected to the first end of the energy storage element 30, the second ends of the first bridge arm, the second bridge arm, and the third bridge arm are connected together to form a second junction, the second end of the energy storage element 30 is connected to a second junction, first ends of the first motor winding, the second motor winding and the third motor winding in the motor 20 are respectively connected to midpoints of the first bridge arm, the second bridge arm and the third bridge arm in a one-to-one correspondence manner, that is, a midpoint D, a midpoint E and a midpoint F shown in fig. 5, respectively, second ends of the first motor winding, the second motor winding and the third motor winding in the motor 20 are connected to an anode of the battery 200, and a cathode of the battery 200 is connected to the second bus end.

When the vehicle state is the preset state, the battery 200, the first bridge arm, the second bridge arm, the first motor winding, the second motor winding, and the energy storage element 30 form a battery heating circuit. The first bridge arm and the second bridge arm are any two-phase bridge arm in the three-phase inverter 10, that is, the first bridge arm and the second bridge arm may be a bridge arm where the midpoint D is located and a bridge arm where the midpoint E is located, may also be a bridge arm where the midpoint D is located and a bridge arm where the midpoint F is located, and may also be a bridge arm where the midpoint E is located and a bridge arm where the midpoint F is located. Correspondingly, the first motor winding and the second motor winding may be any two motor windings in the motor 20, as long as the two motor windings are connected to the midpoint of the first bridge arm and the midpoint of the second bridge arm. In this embodiment, the three-phase inverter and motor of the battery heating circuit may multiplex the three-phase inverter and motor in the vehicle motor drive circuit, and the energy storage element 30 in the battery heating circuit multiplexes the bus capacitance in the motor drive circuit.

In any of the energy conversion devices 100 described in the above two embodiments, to realize self-heating of the battery 200, it is necessary to control the first arm and the second arm of the three-phase inverter 10 in the energy conversion device 100 so that the current value passing through the first motor winding and the second motor winding of the motor 20 connected to the first arm and the second arm satisfies a predetermined condition so that the torque generated by the motor becomes zero while the heating of the battery 200 is realized. Also, during heating of the battery 200, the third bridge arm in the three-phase inverter 10 is in an off state, and the current on the third motor winding in the motor 20 is zero.

Through the technical scheme, under the condition that the battery is heated by using the two-phase motor winding of the motor, the current values passing through the first motor winding and the second motor winding can meet the preset condition by controlling the first bridge arm and the second bridge arm which are connected with the first motor winding and the second motor winding in the energy conversion device, so that the torque generated by the motor in the energy conversion device is controlled to be zero, the function of heating the battery can be realized by using the motor driving circuit, the motor can be prevented from outputting pulsating torque, the service life of the motor is prevented from being influenced, and the safety of a vehicle is ensured.

Fig. 6 is a flowchart illustrating a control method of an energy conversion apparatus according to still another exemplary embodiment of the present disclosure. As shown in fig. 6, the method further includes step 601.

In step 601, when the vehicle state is a preset state, controlling on/off of a first bridge arm and a second bridge arm in a three-phase inverter to enable a battery and an energy storage element to be charged and discharged so as to achieve self-heating of the battery, and during heating, respectively controlling a duty ratio of the first bridge arm and a duty ratio of the second bridge arm to enable a current value passing through a first motor winding and a second motor winding to meet the preset condition so as to enable a torque generated by the motor to be zero, wherein a third bridge arm is in an off state, and a current on a third motor winding is zero.

That is, the current values generated in the first motor winding and the second motor winding can be adjusted by controlling the duty ratios of the first bridge arm and the second bridge arm to which the first motor winding and the second motor winding are respectively connected. The duty ratios corresponding to the first bridge arm and the second bridge arm respectively can be determined according to the preset condition.

In a possible embodiment, the preset condition is that the following formula is satisfied:

i₁+i₂＝i_m， (2)

wherein, the i₁For a target current value on the first motor winding, i₂Is a target current value on the second motor winding, theta is the rotor angle of the motor, i_mThe current value of the N line of the motor is shown.

The motor 20 outputs a pulsating torque due to the space vector of the three-phase motor windings in the motor 20 when current is passed through. When the battery is self-heated by the motor driving circuit, if the motor 20 outputs a pulsating torque, there is a safety hazard, and therefore, the current in the motor 20 needs to be controlled to make the space vector zero, and further, the torque generated by the motor is zero.

Specifically, the current i of the three-phase motor winding in the motor 20 can be obtained first₁,i₂,i₃By a first coordinate transformationIs converted from a natural coordinate system to a static coordinate system and is converted into i_α,i_βThe transformation formula is shown in the following formula (3):

then i is put_α,i_βConverting the static coordinate system into a synchronous rotating coordinate system through second coordinate conversion to obtain a space vector i_qThe transformation formula of (c) is as follows:

the current i in the three-phase motor winding in the motor 20 is finally obtained₁,i₂,i₃I in the synchronous rotation coordinate system_qExpression (c):

in order to make the torque generated by the motor 20 zero, i needs to be made_q0, and since the third bridge limb is switched off during heating, the current on the third motor winding is zero, i.e. i₃0, thus can be according to i above_qExpression (5) of (a) results in expression (1) in the above-mentioned preset condition. Specifically, the first coordinate transformation is Clark transformation, and the second coordinate transformation is Park transformation.

When the energy conversion device 100 is used for realizing self-heating of the battery, for the charging and discharging between the battery 200 and the energy storage element 30 during the heating period, the first arm and the second arm are controlled to enable the current values passing through the first motor winding and the second motor winding to satisfy the formula (1) in the preset condition, so that the torque generated by the motor is zero, and the sum of the current values passing through the first motor winding and the second motor winding is consistent with the current value flowing through the motor N line, namely, the formula (2) in the preset condition is satisfied, so that the energy conversion device 100 can more safely carry out self-heating on the battery 200. And the N line of the motor is a second end outgoing line formed by connecting three-phase motor windings together.

Fig. 7 is a flowchart illustrating a control method of an energy conversion apparatus according to still another exemplary embodiment of the present disclosure. As shown in fig. 7, the method further includes step 701.

In step 701, when the vehicle state is a preset state, the on-off of a first bridge arm and a second bridge arm in the three-phase inverter is controlled, so that the battery and the energy storage element are charged and discharged, and the self-heating of the battery is realized. During heating, according to the corresponding relation between the target current value flowing through the first motor winding and the duty ratio and the corresponding relation between the target current value flowing through the second motor winding and the duty ratio, the target duty ratios corresponding to the first bridge arm and the second bridge arm are respectively obtained, and the on-off of the first bridge arm and the second bridge arm is respectively controlled based on the target duty ratios, so that the torque generated by the motor is zero, wherein the third bridge arm is in an off state, and the current on the third motor winding is zero.

That is, according to the method in step 601 shown in fig. 6, when the current values passing through the first motor winding and the second motor winding satisfy the preset condition by respectively controlling the duty ratio of the first bridge arm and the duty ratio of the second bridge arm, specifically, the target current values respectively corresponding to the first motor winding and the second motor winding may be obtained according to the formula (1) and the formula (2) in the preset condition, and then the target duty ratios respectively corresponding to the first bridge arm and the second bridge arm may be determined according to the target current values. The corresponding relationship between the target current value and the duty ratio may be a corresponding relationship table set in advance according to actual conditions of the energy conversion device 100 and the battery 200, and when the target current values of the first motor winding and the second motor winding are determined, the corresponding target duty ratio is directly searched in the corresponding relationship table, or online real-time closed-loop adjustment is performed according to the target current value at the current moment and the current input value at the previous moment in the control process.

Through the technical scheme, the corresponding relation between the target current value and the duty ratio is preset, so that the torque generated in the process of self-heating the battery 200 by the energy conversion device 100 can be controlled to be zero more quickly and accurately, and the safety of the energy conversion device 100 in self-heating the battery 200 is ensured.

In a possible embodiment, in order to ensure that the current value passing through the first motor winding and the second motor winding meets the preset condition, the heating efficiency of the self-heating of the battery can be adjusted by adjusting the switching frequency of the first bridge arm and the second bridge arm. Specifically, when the duty ratios of the first bridge arm and the second bridge arm are controlled, the on/off switching frequency of the first bridge arm and the second bridge arm can be high frequency or low frequency, the overcurrent capacity of the bridge arms is stronger when a low-frequency control mode is adopted, the current waveform is smoother when a high-frequency control mode is adopted, and the generated ripple is smaller.

In one possible embodiment, the energy storage element 30 as shown in fig. 4 and 5 may be a capacitor. Under the condition that the energy storage element 30 is a capacitor, before the energy conversion device 100 is controlled by a duty ratio to self-heat the battery, since the voltage of the capacitor cannot suddenly change, if the duty ratios of the first arm and the second arm change too fast, the current is increased sharply, the current impact is too large, or the capacitor and a first motor winding and a second motor winding in the motor 20 have a current oscillation problem, before the energy conversion device 100 is controlled by the duty ratio to self-heat the battery, the energy conversion device 100 needs to be subjected to soft start first, that is, an extremely small duty ratio of the first arm and the second arm is given first to enable the energy conversion device 100 to slowly establish the charging and discharging current of the battery 20, and then the duty ratio is slowly increased to enable the charging and discharging current of the battery 200 to gradually increase to complete the soft start, this can prevent the problems of overcurrent and overvoltage of the power conversion apparatus 100 and the battery 200.

In a possible embodiment, the battery 200 and the energy storage element 20 are charged or discharged by controlling the upper arms of the first arm and the second arm to be simultaneously conducted or controlling the lower arms of the first arm and the second arm to be simultaneously conducted. That is, in the process of self-heating the battery 200, the upper arm and the lower arm of the first arm and the second arm of the three-phase inverter 10 in the energy conversion device 100 are simultaneously turned on. Taking fig. 4 as an example, in which the energy storage element 30 is a capacitor, the following four states may occur in the process of self-heating the battery by the energy conversion apparatus 100.

The first state: the upper arms of any two of the three-phase arms in the three-phase inverter 10 are on, the lower arms are off, and the upper and lower arms of the other arm are both off. At this time, the current flows out from the positive electrode of the battery 200, and flows back to the negative electrode of the battery 200 after passing through the two-phase upper bridge arm and the first motor winding and the second motor winding respectively connected to the two-phase upper bridge arm, and the current value continuously increases to the maximum value, and the energy storage of the first motor winding and the second motor winding increases, as shown in fig. 8 a.

And a second state: and controlling the two-phase upper bridge arm of the three-phase inverter 10 to be disconnected, the lower bridge arm of the three-phase inverter to be connected, and the upper bridge arm and the lower bridge arm of the other bridge arm to be disconnected. At this time, because the current of the motor winding cannot change suddenly, the current flows from the motor winding to the capacitor, and flows back to the first motor winding and the second motor winding respectively connected to the two-phase lower bridge arm after passing through the two-phase lower bridge arm, in the process, the current is continuously reduced to zero, the energy stored in the first motor winding and the second motor winding is reduced to zero, and the voltage of the capacitor is increased to a certain maximum value, as shown in fig. 8 b.

And a third state: the two-phase upper arm of the three-phase inverter 10 is kept disconnected and the lower arm is kept on. At this time, the current flows out from the positive electrode of the capacitor, flows to the negative electrode of the capacitor after passing through the first motor winding and the second motor winding respectively connected to the two-phase lower bridge arm and the two-phase lower bridge arm, and in the process, the current increases and then decreases continuously, and the voltage of the capacitor decreases continuously, as shown in fig. 8 c.

And a fourth state: and controlling the two-phase upper bridge arm of the three-phase inverter 10 to be connected, the lower bridge arm of the two-phase upper bridge arm to be disconnected, and the upper bridge arm and the lower bridge arm of the other bridge arm to be disconnected, wherein the connection and disconnection states of the three-phase bridge arm in the state I are the same as those of the three-phase bridge arm in the state I. At this time, the current flows out of the capacitor, flows to the battery through the first motor winding and the second motor winding respectively connected to the two conductive upper bridge arms and the two conductive upper bridge arms, and is continuously reduced to zero in the process, as shown in fig. 8 d.

In one possible embodiment, the electric machine 20 is a drive machine of a vehicle, and the first, second and third machine windings are machine windings of the drive machine.

Fig. 9 is a block diagram illustrating a configuration of a control apparatus of an energy conversion apparatus according to an exemplary embodiment of the present disclosure. The energy conversion device 100 is shown in fig. 1. The control device 300, as shown in fig. 9, includes an acquisition module 301 configured to acquire a vehicle state; the control module 302 is configured to control on/off of the first bridge arm and the second bridge arm in the three-phase inverter to charge and discharge between the battery and the energy storage element so as to achieve self-heating of the battery when the vehicle state is a preset state, and during heating, a current value passing through the first motor winding and the second motor winding meets a preset condition by controlling the first bridge arm and the second bridge arm so as to make a torque generated by the motor zero, where the third bridge arm is in an off state and a current on the third motor winding is zero.

Through the technical scheme, the current values passing through the first motor winding and the second motor winding in the energy conversion device can meet the preset condition by controlling the first bridge arm and the second bridge arm which are connected with the first motor winding and the second motor winding in the energy conversion device, so that the torque generated by the motor in the energy conversion device is controlled to be zero, the occurrence of motor pulsation torque is avoided, the service life of the motor is further prevented from being influenced, and the safety of a vehicle is ensured.

In one possible implementation, the control module 302 is further configured to: respectively controlling the duty ratio of the first bridge arm and the duty ratio of the second bridge arm to enable the current value passing through the first motor winding and the second motor winding to meet the preset condition so as to enable the torque generated by the motor to be zero

In a possible embodiment, the preset condition is that the following formula is satisfied:

i₁+i₂＝i_m，

wherein, the i₁For a target current value on the first motor winding, i₂Is a target current value on the second motor winding, theta is the rotor angle of the motor, i_mThe current value of the N line of the motor is shown.

In one possible implementation, the control module 302 is further configured to: and respectively acquiring target duty ratios corresponding to a first bridge arm and a second bridge arm according to the corresponding relation between the target current value flowing through the first motor winding and the duty ratio and the corresponding relation between the target current value flowing through the second motor winding and the duty ratio, and respectively controlling the on-off of the first bridge arm and the second bridge arm based on the target duty ratios so as to enable the torque generated by the motor to be zero.

In one possible embodiment, the connection relationship between the energy conversion device 100 and the vehicle battery 200 may be as shown in fig. 3: first ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a first bus end, the first bus end is connected with a positive electrode of the battery, second ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a second bus end, the second bus end is connected with a negative electrode of the battery, first ends of the first motor winding, the second motor winding and the third motor winding are respectively connected to middle points of the first bridge arm, the second bridge arm and the third bridge arm in a one-to-one correspondence manner, second ends of the first motor winding, the second motor winding and the third motor winding are connected to a first end of the energy storage element, and a second end of the energy storage element is connected to the second bus end; in the preset state, the battery, the first bridge arm, the second bridge arm, the first motor winding, the second motor winding and the energy storage element form a battery heating circuit; wherein the control module 302 is further configured to: and during heating, controlling the duty ratios of the first bridge arm and the second bridge arm to enable the current values passing through the first motor winding and the second motor winding simultaneously to meet the preset condition so as to enable the torque generated by the motor to be zero.

In one possible embodiment, the connection relationship between the energy conversion device 100 and the vehicle battery 200 may be as shown in fig. 4: first ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a first bus end, the first bus end is connected with a first end of the energy storage element, second ends of the first bridge arm, the second bridge arm and the third bridge arm are connected in common to form a second bus end, the second bus end is connected with a second end of the energy storage element, first ends of the first motor winding, the second motor winding and the third motor winding are respectively connected to middle points of the first bridge arm, the second bridge arm and the third bridge arm in a one-to-one correspondence manner, second ends of the first motor winding, the second motor winding and the third motor winding are connected to a positive electrode of the battery, and a negative electrode of the battery is connected to the second bus end; in the preset state, the battery, the first bridge arm, the second bridge arm, the first motor winding, the second motor winding and the energy storage element form a battery heating circuit; wherein the control module 302 is further configured to: and during heating, controlling the duty ratios of the first bridge arm and the second bridge arm to enable the current values passing through the first motor winding and the second motor winding simultaneously to meet the preset condition so as to enable the torque generated by the motor to be zero.

In one possible implementation, the control module 302 is further configured to: and controlling the upper bridge arms of the first bridge arm and the second bridge arm to be simultaneously conducted or controlling the lower bridge arms of the first bridge arm and the second bridge arm to be simultaneously conducted so as to charge or discharge the battery and the energy storage element.

In one possible embodiment, the first leg and the second leg are any two-phase legs of the three-phase inverter.

In one possible embodiment, the electric machine is a drive machine of a vehicle, and the first, second and third machine windings are machine windings of the drive machine.

In one possible embodiment, the energy storage element is a capacitor.

The present disclosure also provides a vehicle including the control device 300 of the energy conversion device described above.

With regard to the apparatus in the above-described embodiment, the specific manner in which each module performs the operation has been described in detail in the embodiment related to the method, and will not be elaborated here.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, various possible combinations will not be separately described in this disclosure.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.