CN-122026728-A - Partial power converter and control method thereof

CN122026728ACN 122026728 ACN122026728 ACN 122026728ACN-122026728-A

Abstract

The invention discloses a partial power converter and a control method thereof, and relates to the technical field of power electronics. The invention is based on a three-port isolated converter, a first port is connected with direct current as an input port, a second port is connected with the first port in series in the forward direction, a third port is connected with the first port in series in the reverse direction, the whole is used as an output port, and the total output voltage of the output port is the sum of the first port and the second port and the difference of the third port based on a connection mode, therefore, the port voltage of the second port can be controlled to be equal to the preset reference voltage in the step-down mode, the port voltage of the third port can be changed according to the output voltage of the output port, and the port voltage of the third port can be controlled to be equal to the preset reference voltage in the step-up mode, and the port voltage of the second port can be changed according to the output voltage of the output port. The invention realizes the dual-mode operation of boosting and reducing by changing the connection mode of the output port, and improves the operation condition of the converter when the input voltage and the output voltage are close.

Inventors

DONG ZHENG
LIU TIANLONG
Gao Tianqu
HUANG TAO
BAI TIANMING
Tan Minxia

Assignees

山东大学

Dates

Publication Date: 20260512
Application Date: 20260211

Claims (6)

1. The partial power converter is characterized by comprising a three-port isolated direct current-direct current converter, wherein the three-port isolated direct current-direct current converter comprises a first port, a second port and a third port; the first port is connected with direct current and is used as an input port; the second port is in forward series connection with the first port, the third port is in reverse series connection with the first port, and the whole of the first port, the second port and the third port is taken as an output port; when the device works in a step-down mode, controlling the port voltage of the second port to be equal to a preset reference voltage, and enabling the port voltage of the third port to change according to the output voltage change of the output port; when the device works in the boost mode, the port voltage of the third port is controlled to be equal to a preset reference voltage, and the port voltage of the second port is changed according to the change of the output voltage of the output port.
2. The partial power converter of claim 1 wherein a winding ratio of the first port, the second port, and the third port is 1:V base /V 1 :V base /V 1 ; Wherein V base is a preset reference voltage, and V 1 is a port voltage of the first port.
3. The partial power converter according to claim 1, wherein the three-port isolated DC-DC converter comprises an isolated DC-DC converter with three ports as an original structure and a three-port isolated DC-DC converter obtained by connecting the two-port isolated converters in series or in parallel.
4. The partial power converter of claim 1 wherein the first port, the second port, and the third port are each connected in parallel with a support capacitance; And each supporting capacitor is used for stabilizing the port voltage of the corresponding port.
5. The partial power converter of claim 1 wherein said three-port isolated DC-DC converter further comprises a high frequency transformer and a plurality of power transfer inductors; The high-frequency transformer and the power transmission inductors are used for carrying out power transmission, and the output voltage of the output port is obtained according to the adjustment of the input voltage of the input port based on the phase shift.
6. A method of controlling a partial power converter, comprising: Acquiring an output voltage reference value of an output port of the partial power converter, and determining a working mode of the partial power converter according to the output voltage reference value and an input voltage of the partial power converter; If the partial power converter is in the buck mode, setting a port voltage reference value of a second port in the partial power converter as a preset reference voltage, acquiring a port voltage sampling value of the second port in the partial power converter at the current moment and an output voltage sampling value of an output port; if the partial power converter is in the boost mode, setting a port voltage reference value of a third port in the partial power converter as a preset reference voltage, acquiring a port voltage sampling value of the third port in the partial power converter at the current moment and an output voltage sampling value of an output port; And performing phase-shifting modulation according to the phase-shifting ratio to obtain control signals of all switching tubes in the partial power converter so as to control the partial power converter to perform power conversion.

Description

Partial power converter and control method thereof Technical Field The invention relates to the technical field of power electronics, in particular to a partial power converter and a control method thereof. Background In recent years, rapid development of direct current distribution networks, photovoltaic, energy storage, new energy automobiles and the like has promoted urgent demands for efficient high-power direct current-direct current (DC-DC) converters. Therefore, partial power processing (Partial Power Processing, PPP) techniques have been developed to increase efficiency and power density by allowing a large portion of the power to be transferred directly from the source to the load and allowing the converter to process only a small portion of the remaining power, thereby reducing losses and costs. In the prior art, a phase-shifting full-Bridge type partial power converter and a serial type partial power converter such as an MAB (Multi-Active Bridge) partial power converter are all realized by adding an additional power flow path by changing a connection mode, one port of a two-port direct current-direct current converter is connected with a direct current source as an input port, the other port is connected with the input port in series in the forward direction and then is integrally used as an output port, and a bipolar switch is needed to realize the functions of rising and falling. There are also related documents that an H-bridge is added behind the output port of the MAB type partial power converter to form a two-stage partial power converter to realize the step-up and step-down functions, thereby expanding the overall voltage regulation range. In the existing partial power conversion scheme, when the input and output voltages are closer, the output voltage of the internal converter is close to 0, and the partial power converter is often required to work at a very low duty ratio or a very small phase shift angle. The control precision requirement is extremely high, the switching device is easily influenced by parasitic parameters, the power transmission capacity is limited, the dynamic response is poor, and according to the connection mode of the existing partial power converter, the partial power converter can only realize voltage boosting or voltage reducing under the condition that a unipolar switch is used and an H bridge is not added, so that the voltage regulating range of the partial power converter is greatly reduced. Disclosure of Invention In view of the foregoing, it is desirable to provide a partial power converter and a control method thereof. The invention adopts the following technical scheme: The invention provides a partial power converter which comprises a three-port isolated direct current-direct current converter, wherein the three-port isolated direct current-converter comprises a first port, a second port and a third port, the first port is connected with direct current to serve as an input port, the second port is connected with the first port in series in the forward direction, the third port is connected with the first port in series in the reverse direction, the whole of the first port, the second port and the third port serves as an output port, when the partial power converter works in a step-down mode, the port voltage of the second port is controlled to be equal to a preset reference voltage, the port voltage of the third port is controlled to be changed according to the change of the output voltage of the output port, and when the partial power converter works in the step-up mode, the port voltage of the third port is controlled to be equal to the preset reference voltage, and the port voltage of the second port is controlled to be changed according to the change of the output voltage of the output port. The invention provides a control method of a partial power converter, which comprises the steps of firstly obtaining an output voltage reference value of an output port of the partial power converter, and determining a working mode of the partial power converter according to the output voltage reference value and a port voltage of a first port in the partial power converter; If the partial power converter is in the step-down mode, setting a port voltage reference value of a second port in the partial power converter as a preset reference voltage, acquiring a port voltage sampling value of the second port in the partial power converter at the current moment and an output voltage sampling value of an output port; if the partial power converter is in the boost mode, setting a port voltage reference value of a third port in the partial power converter as a preset reference voltage, acquiring a port voltage sampling value of the third port in the partial power converter at the current moment and an output voltage sampling value of an output port; and finally, carrying out phase-shifting modulation according to the phase-shifting ratio to obtain control signals of all s