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CN-122026724-A - Power conversion device and on-board electrical system comprising same

CN122026724ACN 122026724 ACN122026724 ACN 122026724ACN-122026724-A

Abstract

The invention relates to a power conversion device for an on-board electrical system and an on-board electrical system comprising the device. The device comprises a first switching circuit connected between a vehicle battery and a primary side of a first transformer and a second switching circuit connected between a secondary side of the first transformer and a power consuming device, the power conversion device further comprising a super capacitor module connected across two power supply inputs of the second switching circuit, a conversion circuit arranged between the vehicle battery and the super capacitor module for charging the super capacitor module by means of a direct current input voltage of the vehicle battery, and a control loop configured to selectively connect the second switching circuit to the first transformer or the conversion circuit for enabling the power conversion device to perform different power conversion modes.

Inventors

  • LIN YIQING
  • LUO HAIMING
  • HU YI
  • ZHANG HUI

Assignees

  • 纬湃汽车电子(长春)有限公司
  • 纬湃科技投资(中国)有限公司

Dates

Publication Date
20260512
Application Date
20241106

Claims (10)

  1. 1. A power conversion device for an on-board electrical network comprising a vehicle battery and a power consuming device to be powered by the vehicle battery, the power conversion device comprising a resonant cavity and a first transformer (T1) for performing an isolation transformation operation between the vehicle battery and the power consuming device, the power conversion device further comprising a first switching circuit connected between the vehicle battery and a primary side of the first transformer and a second switching circuit connected between a secondary side of the first transformer and the power consuming device, characterized in that the power conversion device further comprises: the super capacitor module is connected between two power input ends of the second switch circuit in a bridging way; a conversion circuit provided between the vehicle battery and the super capacitor module for charging the super capacitor module by means of a DC input voltage of the vehicle battery, and A control loop configured to selectively connect the second switching circuit to the first transformer (T1) or the conversion circuit to cause the power conversion device to perform different power conversion modes.
  2. 2. The power conversion device according to claim 1, characterized in that the second switching circuit adopts a full-bridge topology consisting of two half-bridges, wherein the control loop comprises an inductive element (Lr 2), a first switching element (S1) and a second switching element (S2), the first switching element comprising one movable contact and two stationary contacts, a first of the two stationary contacts being connected to the secondary side of the first transformer (T1), a second stationary contact being connected to a bridge node of the first half-bridge in the full-bridge topology, the inductive element (Lr 2) being connected between the movable contact of the first switching element (S1) and the bridge node of the second half-bridge in the full-bridge topology, the second switching element (S2) being connected between the power input of the first half-bridge and the power input of the second half-bridge.
  3. 3. A power conversion device according to claim 2, characterized in that the power conversion device enters a first operating mode in which the power consumer is supplied with power by means of the power conversion device by means of the vehicle battery when the movable contact of the first switching element (S1) is brought into contact with the first stationary contact and the second switching element (S2) is closed.
  4. 4. A power conversion device according to claim 2 or 3, characterized in that the power conversion device enters a second operating mode in which the super capacitor module is charged with the vehicle battery by means of the power conversion device when the movable contact of the first switching element (S1) is on the second stationary contact and the second switching element (S2) is off.
  5. 5. A power conversion device according to any one of claims 1 to 3, wherein the conversion circuit is formed as a flyback power supply.
  6. 6. The power conversion device according to claim 5, characterized in that the flyback power supply comprises a second transformer (T2), the primary side of which is connected in parallel with the vehicle battery and the secondary side of which is connected in parallel with the second switching circuit.
  7. 7. The power conversion device according to claim 6, characterized in that the flyback power further comprises a power switch (Q9) connected between the primary side of the second transformer and the vehicle battery and a diode (D1) with its positive pole connected to the secondary side of the second transformer and its negative pole connected to the second switching circuit.
  8. 8. A power conversion device according to any one of claims 1 to 3, wherein the first switching circuit is formed as a full bridge inverter and the second switching circuit is formed as a full bridge rectifier.
  9. 9. A power conversion device according to claim 8, characterized in that a first capacitor (C1) is connected across the two power supply inputs of the full bridge inverter and a second capacitor (C2) is connected across the two power supply inputs of the full bridge rectifier.
  10. 10. An on-board electrical network comprising a vehicle battery and an electrical consumer to be powered by the vehicle battery, characterized in that the on-board electrical network further comprises a power conversion device according to any one of claims 1 to 9.

Description

Power conversion device and on-board electrical system comprising same Technical Field The present invention relates to the field of power conversion technology of vehicles, and more specifically to a power conversion device for an on-board electrical network, and an on-board electrical network including the power conversion device. Background In new energy vehicles, the high-voltage to low-voltage dc converter (HV-LV DCDC) plays a vital role, which is responsible for supplying a stable dc power to the low-voltage system of the vehicle. Conventional HV-LV DCDC systems rely on low-side parallel-connected batteries to meet the low-voltage backup demand of the vehicle. However, with increasing demands for reducing carbon emissions, the capacity of the battery is becoming increasingly smaller, and even part of the battery is replaced by a supercapacitor (Supercapacitor, abbreviated as "SC"). There are some drawbacks to current HV-LV DCDC converters. For example, when the electric vehicle is in a parking mode and the main switch (main relay) is turned off, the low-voltage network is powered by the battery, and the super capacitor is used as a backup. However, when the super capacitor is under-charged, it must be charged by the low-voltage battery, which means that the use of the low-voltage battery cannot be completely canceled. In addition, supercapacitors require charging from the battery by means of a separate buck-boost circuit, which further increases the complexity of the system and the cost of the circuit. Disclosure of Invention In order to overcome the drawbacks of the conventional HV-LV DCDC converter, the present invention proposes a new topology of the power conversion device, which aims to eliminate the use of low-voltage batteries completely, thus reducing the overall circuit cost and volume of the system. A first aspect of the present invention proposes a power conversion device for an on-board electrical power system including a vehicle battery and a power consumption apparatus to be powered by the vehicle battery, the power conversion device including a resonant cavity and a first transformer for performing an isolation transforming operation between the vehicle battery and the power consumption apparatus, the power conversion device further including a first switching circuit connected between the vehicle battery and a primary side of the first transformer and a second switching circuit connected between a secondary side of the first transformer and the power consumption apparatus, the power conversion device further comprising: the super capacitor module is connected between two power input ends of the second switch circuit in a bridging way; a conversion circuit provided between the vehicle battery and the super capacitor module for charging the super capacitor module by means of a DC input voltage of the vehicle battery, and A control loop configured to selectively connect the second switching circuit to the first transformer or the conversion circuit to cause the power conversion device to perform different power conversion modes. According to an alternative embodiment, the second switching circuit adopts a full-bridge topology consisting of two half-bridges, wherein the control loop comprises an inductive element, a first switching element and a second switching element, the first switching element comprising a movable contact and two stationary contacts, a first stationary contact of the two stationary contacts being connected to the secondary side of the first transformer, a second stationary contact being connected to a bridge node of a first half-bridge of the full-bridge topology, the inductive element being connected between the movable contact of the first switching element and the bridge node of a second half-bridge of the full-bridge topology, the second switching element being connected between a power input of the first half-bridge and a power input of the second half-bridge. According to an alternative embodiment, the power conversion device enters a first operating mode in which the power consumer is supplied with power by means of the vehicle battery by means of the power conversion device when the movable contact of the first switching element opens the first stationary contact and the second switching element closes. According to an alternative embodiment, the power conversion device enters a second operating mode in which the super capacitor module is charged with the vehicle battery by means of the power conversion device when the movable contact of the first switching element is on the second stationary contact and the second switching element is off. According to an alternative embodiment, the conversion circuit is formed as a flyback power supply. According to an alternative embodiment, the flyback power supply comprises a second transformer, the primary side of which is connected in parallel with the vehicle battery, and the secondary side of which is connected in par