CN-121984318-A - Power conversion device

Abstract

The application provides a power conversion device which comprises a power converter, a first controller, a first compensation unit, a limiting unit, a second compensation unit and a second compensation unit, wherein the power converter comprises a bidirectional AC/DC converter, a direct current bus and a bidirectional DC/DC converter which are connected in a cascading mode, the first controller is configured to execute the first operation unit to receive an alternating current voltage sampling signal from an alternating current end of the bidirectional AC/DC converter and an alternating current voltage reference signal and output an alternating current voltage difference signal, the first compensation unit receives the alternating current voltage difference signal and outputs a compensated alternating current voltage difference signal, the limiting unit receives the alternating current voltage difference signal and a bus voltage sampling signal from the direct current bus and outputs a current reference signal, the second operation unit receives the alternating current sampling signal from the alternating current end and the current reference signal and outputs an alternating current difference signal, and the first modulation unit receives the compensated alternating current difference signal and outputs a first switch control signal.

Inventors

• CHEN LIHONG
• LU HAO
• MA FEIHONG
• KANG JIAYI

Assignees

• 浙江富特科技股份有限公司

Dates

Publication Date

20260505

Application Date

20260206

Claims (9)

1. 1. A power conversion apparatus, comprising: the power converter comprises a bidirectional AC/DC converter, a direct current bus and a bidirectional DC/DC converter which are connected in cascade; a first controller configured to perform, when the power converter is operating in an inverter mode: The first operation unit receives an alternating voltage sampling signal and an alternating voltage reference signal from an alternating terminal of the bidirectional AC/DC converter and outputs an alternating voltage difference signal; The first compensation unit receives the alternating voltage difference signal and outputs a compensated alternating voltage difference signal; The amplitude limiting unit receives the compensated alternating voltage difference signal and a bus voltage sampling signal from the direct current bus and outputs a current reference signal; the second operation unit receives the alternating current sampling signal from the alternating current end and the current reference signal and outputs an alternating current difference signal; The second compensation unit receives the alternating current difference signal and outputs a compensated alternating current difference signal; The first modulation unit receives the compensated alternating current difference signal and outputs a first switch control signal for controlling a switch tube in the bidirectional AC/DC converter.
2. 2. The power conversion device of claim 1, further comprising a second controller configured to perform, when the power converter is operating in an inverter mode: the third operation unit receives a bus voltage sampling signal from the direct current bus and a bus voltage reference signal and outputs a bus voltage difference signal; The third compensation unit receives the bus voltage difference signal and outputs a compensated bus voltage difference signal; and the second modulation unit receives the compensated bus voltage difference signal and outputs a second switch control signal for controlling a switch tube in the DC/DC converter.
3. 3. The power conversion device according to claim 1, wherein when the bus voltage sampling signal decreases, the limited single output current reference signal also decreases to ensure the dc bus voltage is stable.
4. 4. The power conversion device according to claim 1, wherein when the bus voltage sampling signal increases, the limited single output current reference signal also increases to ensure the dc bus voltage is stable.
5. 5. The power conversion device of claim 1, wherein the bi-directional AC/DC converter is a PFC converter.
6. 6. The power conversion device of claim 1, wherein the bi-directional AC/DC converter is a single-phase converter or a three-phase converter.
7. 7. The power conversion device according to claim 5, wherein the bi-directional DC/DC converter is an LLC resonant converter.
8. 8. The power conversion device of claim 2, wherein when the power converter is operating in a rectifying mode that converts alternating current to direct current, the first controller is configured to output a first switching control signal that controls switching tubes within the bi-directional AC/DC converter based on an alternating voltage sampling signal and an alternating current sampling signal from an alternating current terminal of the bi-directional AC/DC converter and a bus voltage sampling signal from the direct current bus.
9. 9. The power conversion device of claim 8, wherein the second controller is configured to output a second switch control signal that controls a switching tube within the bi-directional DC/DC converter based on the voltage and current sampling signals from the DC output of the bi-directional DC/DC converter and the bus voltage sampling signal from the DC bus.

Description

Power conversion device Technical Field The application relates to the field of power supplies, in particular to a power conversion device. Background Two-stage power converters comprising a bi-directional AC/DC converter, a DC bus and a bi-directional DC/DC converter connected in cascade are used in many applications, such as electric vehicles, where the DC side of the power converter is used for connecting a high voltage power battery and the AC side is used for connecting an AC grid or an AC consumer. When the direct current of the power converter is connected with a load and power is required to be supplied, the power converter is controlled to work in a rectification mode for converting alternating current into direct current. When the alternating current end of the power converter is connected with an alternating current load and power supply is needed, the power converter is controlled to work in an inversion mode of converting direct current into alternating current. In practical applications, it is desirable that the power converter be stable and reliable during operation, and that the power converter be as small as possible to meet the current market pursuit of high power density. Content of the application The application provides a power conversion device which comprises a power converter, a first controller, a second controller, a first compensation unit, a first modulation unit, a limiting unit, a second compensation unit and a first switch control signal, wherein the power converter comprises a bidirectional AC/DC converter, a direct current bus and a bidirectional DC/DC converter which are connected in a cascading mode, when the power converter works in an inversion mode, the first controller is configured to execute the steps of receiving an alternating current voltage sampling signal from an alternating current end of the bidirectional AC/DC converter and an alternating current voltage reference signal, outputting an alternating current voltage difference signal, the first compensation unit receives the alternating current voltage difference signal, outputting a compensated alternating current voltage difference signal, the limiting unit receives the compensated alternating current voltage difference signal and a bus voltage sampling signal from the direct current bus, outputting a current reference signal, the second operation unit receives the alternating current sampling signal from the alternating current end and the current reference signal, outputting an alternating current difference signal, and the second compensation unit receives the alternating current difference signal, and outputs a first switch control signal for controlling an internal switch of the bidirectional AC/DC converter. Still further, the DC/DC converter further comprises a second controller, wherein when the power converter works in an inversion mode, the second controller is configured to execute the steps of receiving a bus voltage sampling signal from the DC bus and a bus voltage reference signal and outputting a bus voltage difference signal, receiving the bus voltage difference signal and outputting a compensated bus voltage difference signal by a third compensation unit, and receiving the compensated bus voltage difference signal by a second modulation unit and outputting a second switch control signal for controlling a switch tube in the DC/DC converter. Furthermore, when the bus voltage sampling signal is reduced, the current reference signal output by the limiting single output is also reduced so as to ensure that the DC bus voltage is stable. Furthermore, when the busbar voltage sampling signal increases, the current reference signal output by the limiting single output also increases so as to ensure the voltage stability of the direct current busbar. Further, the bidirectional AC/DC converter is a PFC converter. Further, the bidirectional AC/DC converter is a single-phase converter or a three-phase converter. Further, the bi-directional DC/DC converter is an LLC resonant converter. Further, when the power converter is operated in a rectifying mode for converting alternating current into direct current, the first controller is configured to output a first switching control signal for controlling switching tubes in the bidirectional AC/DC converter according to an alternating voltage sampling signal and an alternating current sampling signal from an alternating current end of the bidirectional AC/DC converter and a bus voltage sampling signal from the direct current bus. Further, the second controller is configured to output a second switch control signal for controlling a switching tube in the bidirectional DC/DC converter according to a voltage sampling signal and a current sampling signal from a DC output terminal of the bidirectional DC/DC converter and a bus voltage sampling signal from the DC bus. The foregoing has outlined rather broadly the features and technical advantages of the present disclosu