CN-122001223-A - Power conversion device for vehicle-mounted electrical system and vehicle-mounted electrical system

Abstract

The present invention relates to a power conversion device for an in-vehicle electrical system and an in-vehicle electrical system including the same. The system comprises at least one motor and a motor inverter, the apparatus further comprising a controller and at least one switching assembly, the controller being configured to switch the power conversion apparatus between different modes of operation by controlling the on-off state of the respective switching elements in the at least one switching assembly, the modes of operation of the power conversion apparatus comprising an electric drive mode and a power conversion mode, the controller being further configured to zero the inter-phase volt-second product between the respective phase outputs of the at least one motor inverter by selecting an appropriate pulse modulation strategy in said power conversion mode, thereby ensuring that no direct current voltage component and/or no low frequency alternating current voltage component is generated on the respective phase windings of the at least one motor while the at least one motor and the at least one motor inverter remain unbroken.

Inventors

• HU WEI
• LI ZHICHAO
• ZHANG XUECHENG
• CUI XINXU

Assignees

• 纬湃科技投资(中国)有限公司

Dates

Publication Date

20260508

Application Date

20241106

Claims (9)

1. 1. A power conversion device for an on-board electrical system comprising at least one motor and at least one motor inverter for driving the at least one motor, the power conversion device comprising a first conversion circuit, a transformer and a second conversion circuit, the first and second conversion circuits comprising a direct current side and an alternating current side, respectively, the transformer comprising a primary side and a secondary side, wherein the direct current side of the first conversion circuit is connected to an input power source, the alternating current side of the first conversion circuit is connected to the primary side of the transformer, the alternating current side of the second conversion circuit is connected to the secondary side of the transformer, the direct current side of the second conversion circuit is connected to a load, Characterized in that the first and/or second conversion circuit is/are acted on by the at least one motor inverter of the vehicle electrical system, and in that the power conversion device further comprises a controller and at least one switching assembly arranged between the at least one motor inverter and the primary side or the secondary side of the transformer, the controller being configured to switch the power conversion device between different modes of operation by controlling the on-off state of the respective switching element in the at least one switching assembly, Wherein the operating modes of the power conversion device include an electric drive mode and a power conversion mode, and the controller is further configured to zero the inter-phase volt-second product between the phase outputs of the at least one motor inverter by selecting an appropriate pulsing strategy in the power conversion mode to ensure that no direct voltage component and/or low frequency alternating voltage component is generated on the phase windings of the at least one motor while the at least one motor remains disconnected from the at least one motor inverter.
2. 2. The power conversion device according to claim 1, characterized in that the on-board electrical system comprises a first and a second motor and a first and a second motor inverter for driving the first and the second motor, respectively, wherein the first motor inverter acts as the first conversion circuit and/or the second motor inverter acts as the second conversion circuit, the power conversion device comprising a first switching assembly arranged between the first motor inverter and a primary side of the transformer and/or a second switching assembly arranged between the second motor inverter and a secondary side of the transformer.
3. 3. The power conversion device according to claim 2, wherein the first and second motors are three-phase motors, the first and second motor inverters are implemented as three-phase full-bridge circuits, three output terminals of the three-phase full-bridge circuits are respectively connected to one phase winding of a corresponding one of the three-phase motors, and each of the switching elements of the first and second switching assemblies is disposed between one phase winding of the corresponding one of the three-phase motors and a corresponding one of the terminals on the secondary side of the transformer.
4. 4. A power conversion device according to claim 2 or 3, wherein the controller is further configured to: Closing at least one switching element of the first switching assembly and/or the second switching assembly to operate the power conversion device in a power conversion mode, or All switching elements in the first switching assembly and/or the second switching assembly are opened to operate the power conversion device in an electrically driven mode.
5. 5. A power conversion device according to claim 2 or 3, characterized in that the on-board electrical system further comprises a power factor correction module arranged in the on-board charger, the first conversion circuit being acted on by the at least one motor inverter, the dc end of the second conversion circuit being connected to the dc end of the inverter bridge in the power factor correction module, the ac end of the inverter bridge in the power factor correction module being connected to a load.
6. 6. The power conversion device of claim 5, further comprising a main switching circuit disposed between the dc side of the first conversion circuit and the input power source, and wherein the operating mode of the power conversion device further comprises an on-board charging mode, wherein the power conversion device operates in the on-board charging mode when all switching elements in the main switching circuit, the first switching assembly, and the second switching assembly are closed.
7. 7. The power conversion device of claim 6, further comprising a dc charge switch disposed between a neutral point of the at least one electric machine and a dc fast charge port of the vehicle, and wherein the operating mode of the power conversion device further comprises a dc fast charge mode, wherein the power conversion device operates in the dc fast charge mode when the switching elements in the first and second switching assemblies are both open and all switching elements in the dc charge switch and the main switching circuit are both closed.
8. 8. A power conversion device according to any one of claims 1 to 3, wherein the controller is further configured to implement the power conversion device as a single-phase converter or a multi-phase converter by controlling the on-off state of each switching element in the at least one switching assembly.
9. 9. An on-board electrical system comprising at least one electric motor, at least one motor inverter for driving the at least one electric motor, and a power factor correction module provided in an on-board charger, characterized in that the system further comprises a power conversion device according to any one of claims 1 to 8.

Description

Power conversion device for vehicle-mounted electrical system and vehicle-mounted electrical system Technical Field The present invention relates to the field of power conversion, and more particularly, to a power conversion apparatus for an in-vehicle electrical system, and an in-vehicle high-voltage electrical system including the same. Background With the rapid development of the electric vehicle industry, performance requirements for electric vehicles are increasing, especially in terms of cost control, volume optimization and weight saving. The power conversion system of the electric vehicle is a core component part of the electric vehicle and comprises key components such as a motor driving inverter and the like. Currently, the power conversion system of an electric vehicle generally has the problems of high cost, large volume and heavy weight. These problems not only increase the production cost of the electric vehicle, but also limit its competitiveness in the market place. In order to reduce the circuit cost of vehicle power conversion systems and increase the power density of the systems, a variety of all-in-one integrated power products have been developed. However, most of these integration schemes only stay at the level of the shared housing and do not go deep into more critical components, such as inverter legs and motors, and the cost and volume of these components occupy a large part of the whole system. Disclosure of Invention The present invention addresses the limitations of existing power conversion systems in terms of cost and power density and provides an efficient and economical solution for the design of a multi-functional integrated power conversion device. In particular, the power conversion device of the invention achieves cost-effective improvement and power density increase by avoiding the use of additional high-power switches, and improves the stability and efficiency of the system by optimizing the use of high-frequency pulse modulation strategy and motor inductance. A first aspect of the invention provides a power conversion device for an on-board electrical system comprising at least one motor and at least one motor inverter for driving the at least one motor, the power conversion device comprising a first conversion circuit, a transformer and a second conversion circuit, the first and second conversion circuits comprising a direct current side and an alternating current side, respectively, the transformer comprising a primary side and a secondary side, wherein the direct current side of the first conversion circuit is connected to an input power source, the alternating current side of the first conversion circuit is connected to the primary side of the transformer, the alternating current side of the second conversion circuit is connected to the secondary side of the transformer, the direct current side of the second conversion circuit is connected to a load, Wherein the first and/or second conversion circuit is served by the at least one motor inverter of the on-board electrical system, and the power conversion device further comprises a controller and at least one switching assembly arranged between the at least one motor inverter and a primary side or a secondary side of the transformer, the controller being configured to switch the power conversion device between different operation modes by controlling the on-off state of the respective switching element in the at least one switching assembly, Wherein the operating modes of the power conversion device include an electric drive mode and a power conversion mode, and the controller is further configured to zero the inter-phase volt-second product between the phase outputs of the at least one motor inverter by selecting an appropriate pulsing strategy in the power conversion mode to ensure that no direct voltage component and/or low frequency alternating voltage component is generated on the phase windings of the at least one motor while the at least one motor remains disconnected from the at least one motor inverter. According to an alternative embodiment, the on-board electrical system comprises a first and a second motor and a first and a second motor inverter for driving the first and the second motor, respectively, wherein the first motor inverter acts as the first conversion circuit and/or the second motor inverter acts as the second conversion circuit, the power conversion device comprising a first switching assembly arranged between the first motor inverter and a primary side of the transformer and/or a second switching assembly arranged between the second motor inverter and a secondary side of the transformer. According to an alternative embodiment, the first and second electric machines are three-phase electric machines, the first and second electric machine inverters are implemented as three-phase full-bridge circuits, three output terminals of which are connected to one phase winding of a respective one of the