CN-122001175-A - Power conversion device, electric drive system, and vehicle

CN122001175ACN 122001175 ACN122001175 ACN 122001175ACN-122001175-A

Abstract

The present disclosure relates to a power conversion device including a first conversion circuit and a second conversion circuit in cascade. The first conversion circuit comprises a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm, and the second conversion circuit comprises a fifth bridge arm and a sixth bridge arm. The switching devices of the first bridge arm, the second bridge arm and the third bridge arm are included in the first power module, and after the midpoints of the second bridge arm and the third bridge arm are short-circuited, the switching devices are connected to the third phase line through the second connection end of the first power module. Switching devices of the fourth leg, the fifth leg, and the sixth leg are included in the second power module. The device characteristics of the switching devices in the first power module are the same, and the device characteristics of the switching devices in the second power module are the same. The disclosure also relates to an electric drive system and a vehicle.

Inventors

CHI SHANGYANG
HE CHEN
XI YIYI
XIONG XIAOWU

Assignees

法雷奥新能源汽车(深圳)有限公司

Dates

Publication Date: 20260508
Application Date: 20241107

Claims (12)

1. A power conversion device comprising a first conversion circuit and a second conversion circuit, the first conversion circuit being cascaded with the second conversion circuit and connected to a first phase line, a second phase line and a third phase line; the first conversion circuit comprises a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm, and the second conversion circuit comprises a fifth bridge arm and a sixth bridge arm; Wherein the switching devices of the first, second and third legs are included in a first power module, and a midpoint of the first leg is connected to the first phase line via a first connection end of the first power module, and the midpoint of the second and third legs is connected to the third phase line via a second connection end of the first power module after being shorted, Wherein the switching devices of the fourth leg, the fifth leg and the sixth leg are included in a second power module, and a midpoint of the fourth leg is connected to the second phase line via a first connection of the second power module, the midpoints of the fifth leg and the sixth leg are connected to a fourth connection and a fifth connection of the second power module, respectively, Wherein the device characteristics of the switching devices in the first power module are the same, and the device characteristics of the switching devices in the second power module are the same.
2. The power conversion apparatus according to claim 1, wherein a power transmission direction is from the first conversion circuit to the second conversion circuit, When the input of the first conversion circuit is three-phase alternating voltage signals, the voltage signals applied to the first phase line, the second phase line and the third phase line are the same, the phases are different by 120 degrees, Wherein the switching devices in the first power module and the switching devices on the fourth leg in the second power module both operate at a first frequency, and the first frequency is greater than 20kHz.
3. The power conversion apparatus according to claim 1, wherein a power transmission direction is from the first conversion circuit to the second conversion circuit, When the input of the first conversion circuit is a single-phase alternating-current voltage signal, the voltage signals applied to the first phase line and the second phase line are the same, the phase difference is 0 degrees, and the third phase line is a neutral line, wherein the switching devices on a first bridge arm in the first power module and the switching devices on a fourth bridge arm in the second power module are all operated at a first frequency, the first frequency is larger than 20kHz, the switching devices on the second bridge arm and the switching devices on the third bridge arm in the first power module are all operated at a second frequency, and the second frequency is lower than the first frequency.
4. The power conversion device according to claim 3, wherein, The switching devices on the first bridge arm and the switching devices on the same position on the fourth bridge arm are alternately turned on and off to form an alternate parallel structure.
5. The power conversion device of claim 1, wherein the first conversion circuit further comprises a first inductance, a second inductance, and a third inductance, and wherein, A first end of the first inductor is connected with the first phase line and a second end of the first inductor is connected with a first connecting end of the first power module; a first end of the second inductor is connected with the second phase line and a second end of the second inductor is connected with a first connection end of the second power module, and The first end of the third inductor is connected with the third phase line and the second end of the third inductor is connected with the second connecting end of the first power module.
6. The power conversion device according to claim 1, wherein, The first ends of the first bridge arm, the second bridge arm and the third bridge arm are respectively connected with the third connecting end of the first power module, the second ends of the first bridge arm, the second bridge arm and the third bridge arm are respectively connected with the fourth connecting end of the first power module, and The first end of the fourth bridge arm is connected with the third connecting end of the first power module and the second connecting end of the second power module, and the second end of the fourth bridge arm is connected with the fourth connecting end of the first power module and the third connecting end of the second power module.
7. The power conversion device according to claim 1, wherein, The first bridge arm comprises a first switching device arranged on the upper bridge arm and a second switching device arranged on the lower bridge arm; the second bridge arm comprises a third switching device arranged on the upper bridge arm and a fourth switching device arranged on the lower bridge arm; the third bridge arm comprises a fifth switching device arranged on the upper bridge arm and a sixth switching device arranged on the lower bridge arm; the fourth bridge arm includes a seventh switching device arranged on the upper bridge arm and an eighth switching device arranged on the lower bridge arm, and The fifth leg and the sixth leg of the second conversion circuit include four switching devices, and The first power module and the second power module are power modules with six switching devices packaged inside respectively.
8. The power conversion device according to claim 7, wherein, The third switching device and the fifth switching device are turned on and off synchronously, and the fourth switching device and the sixth switching device are turned on and off synchronously.
9. The power conversion device according to claim 1, wherein, When the power transmission direction is from the first conversion circuit to the second conversion circuit, the first conversion circuit is an AC-DC conversion circuit and is used for providing DC power converted by AC power from the first phase line, the second phase line and the third phase line to the second conversion circuit, and the second conversion circuit is a DC-AC conversion circuit or a DC-DC conversion circuit, or When the power transmission direction is from the second conversion circuit to the first conversion circuit, the second conversion circuit is an AC-DC conversion circuit or a DC-DC conversion circuit, the first conversion circuit is a DC-AC conversion circuit and AC power for converting DC power output by the second conversion circuit is output via the first phase line, the second phase line, and the third phase line.
10. The power conversion device according to claim 1, wherein, The second conversion circuit is a DC-DC conversion circuit, wherein the second conversion circuit includes a primary side circuit, an isolation stage circuit, and a secondary side circuit, and Wherein when the power transmission direction is from the first conversion circuit to the second conversion circuit, the primary side circuit includes the fifth leg and the sixth leg, an input terminal of the isolation stage circuit is connected to a fourth connection terminal and the fifth connection terminal of the second power module, and an input terminal of the secondary side circuit is connected to an output terminal of the isolation stage circuit and includes a seventh leg and an eighth leg, and wherein switching devices on the seventh leg and the eighth leg are included in a third power module, or Wherein when a power transmission direction is from the second conversion circuit to the first conversion circuit, the secondary side circuit includes the fifth leg and the sixth leg, an output terminal of the isolation stage circuit is connected to a fourth connection terminal and the fifth connection terminal of the second power module, and an input terminal of the primary side circuit receives DC power, an output terminal of the primary side circuit is connected to an input terminal of the isolation stage circuit, the primary side circuit includes a seventh leg and an eighth leg, and switching devices on the seventh leg and the eighth leg are included in the third power module.
11. An electric drive system comprising the power conversion device according to any one of claims 1 to 10.
12. A vehicle comprising an electric drive system according to claim 11.

Description

Power conversion device, electric drive system, and vehicle Technical Field The present disclosure relates to the field of power conversion, and in particular to a power conversion device, an electric drive system, and a vehicle. Background Power conversion technology is critical in the design and use of power systems. Common power conversion devices include various power conversion circuits, such as an ac-DC conversion circuit, a DC-DC power conversion circuit, and the like. These power conversion circuits typically include a plurality of switching devices (also referred to herein as switching tubes), and in addition, switching devices with higher current carrying capability, such as MOSFES/IGBT discrete devices, may be selected in some cases to meet the current requirements in the circuit. These switching devices, particularly discrete devices such as MOSFES/IGBTs, are typically of large volume and high insulation requirements. As the volume requirements of circuit switching devices become more demanding, it is a more urgent need to reduce the volume of power switching devices. In the mainstream solution, all switching devices of various power conversion circuits of the circuit conversion device can be packaged in one or more power modules, which reduces the installation volume to some extent and can meet the insulation requirement. In addition, the cost of the power module is also a factor to be considered, and in general, the better the device characteristics (for example, current carrying capability) of the switching devices in the power module, the higher the cost and the larger the volume. Therefore, how to package its switching devices into individual power modules according to the specific circuit structure of the circuit switching device to reduce the volume and cost as much as possible is an important point of study in the art. Disclosure of Invention In order to solve the above-described problems, the present disclosure provides a power conversion device, an electric drive system, and a vehicle that achieve standardized design, manufacture, and assembly of a power module, save costs, and reduce occupied space. The embodiment of the disclosure provides a power conversion device, which comprises a first conversion circuit and a second conversion circuit, wherein the first conversion circuit is cascaded with the second conversion circuit and is connected to a first phase line, a second phase line and a third phase line, the first conversion circuit comprises a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm, and the second conversion circuit comprises a fifth bridge arm and a sixth bridge arm, wherein the switching devices of the first bridge arm, the second bridge arm and the third bridge arm are included in a first power module, the midpoint of the first bridge arm is connected to the first phase line through a first connection end of the first power module, the midpoint of the second bridge arm and the midpoint of the third bridge arm are connected to the third phase line through a second connection end of the first power module after being shorted, the switching devices of the fourth bridge arm, the fifth bridge arm and the sixth bridge arm are included in a second power module, and the midpoint of the fourth bridge arm is connected to the fifth bridge arm through a second connection end of the second power module, the midpoint of the fourth bridge arm is connected to a fifth phase line of the fifth power module, and the switching devices of the fifth bridge arm is connected to the fifth phase line of the fifth power module, and the switching devices of the fifth phase line is connected to the fifth phase line of the switching devices of the fifth phase line is connected to the fifth phase line of the switching devices. According to an embodiment of the disclosure, the power transmission direction is from the first conversion circuit to the second conversion circuit, and when the input of the first conversion circuit is a three-phase alternating voltage signal, the voltage signals applied on the first phase line, the second phase line and the third phase line are identical and differ in phase by 120 °, wherein the switching devices in the first power module and the switching devices on the fourth leg in the second power module each operate at a first frequency, and the first frequency is greater than 20kHz. According to an embodiment of the disclosure, a power transmission direction is from the first conversion circuit to the second conversion circuit, when an input of the first conversion circuit is a single-phase alternating voltage signal, voltage signals applied on the first phase line and the second phase line are the same, and differ in phase by 0 °, and the third phase line is a neutral line, wherein switching devices on a first leg in the first power module and switching devices on a fourth leg in the second power module each operate at a first frequenc