KR-20260064725-A - Series-to-parallel switching circuit for bidirectional power conversion

KR20260064725AKR 20260064725 AKR20260064725 AKR 20260064725AKR-20260064725-A

Abstract

The present application provides a series-parallel switching circuit for bidirectional power conversion. The series-parallel switching circuit for bidirectional power conversion includes a first bidirectional DC voltage source and a second bidirectional DC voltage source, a first bidirectional DC/DC isolation conversion circuit and a second bidirectional DC/DC isolation conversion circuit, a series-parallel switching switch, a first output filter capacitor and a second output filter capacitor, a discharge circuit, and a soft start circuit. The series-parallel switching switch is configured to connect the first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit in series or in parallel. When the series-parallel switching switch is switched, the voltage across the first output filter capacitor and the voltage across the second output filter capacitor do not change. The circuit can implement a high-speed series-parallel switching function of the bidirectional DC/DC isolation conversion circuit and significantly improves the applicability of the bidirectional DC/DC isolation conversion circuit.

Inventors

첸 시아오핑
장 카이수안
장 하이동
첸 양하오
우 이사이
장 유싱
주 지안구오

Assignees

셴?? 윈라인 테크놀로지 컴퍼니 리미티드

Dates

Publication Date: 20260507
Application Date: 20240926
Priority Date: 20230926

Claims (10)

As a series-parallel switching circuit for bidirectional power conversion, It includes a first bidirectional DC voltage source and a second bidirectional DC voltage source, a first bidirectional DC/DC isolation conversion circuit and a second bidirectional DC/DC isolation conversion circuit, a series-parallel switching switch, a first output filter capacitor and a second output filter capacitor, a discharge circuit, and a soft start circuit. The first bidirectional DC voltage source and the second bidirectional DC voltage source are configured to provide a DC voltage for bidirectional power conversion, and the direction from the first bidirectional DC voltage source to the second bidirectional DC voltage source is a forward energy transfer direction. The first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit are configured to implement a bidirectional DC/DC function, and The above series-parallel switching switch connects the first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit in series or parallel, so that the series-parallel switching circuit for bidirectional power conversion performs switching operation in a series operation mode or a parallel operation mode, and The first output filter capacitor is the output filter capacitor of the first bidirectional DC/DC isolation conversion circuit, and the second output filter capacitor is the output filter capacitor of the second bidirectional DC/DC isolation conversion circuit; when the series-parallel switching switch is switched, the voltage across the first output filter capacitor and the voltage across the second output filter capacitor do not change. The above discharge circuit is configured to discharge the first output filter capacitor and the second output filter capacitor when the power supply to the circuit is cut off, and A series-parallel switching circuit for bidirectional power conversion, characterized in that the soft start circuit includes a soft start relay switch and a soft start resistor, and is configured to perform capacitance precharging on both the first output filter capacitor and the second output filter capacitor to maintain the voltage difference between the first bidirectional DC voltage source or the second bidirectional DC voltage source and the first output filter capacitor and the second output filter capacitor within a preset range.
In Article 1, The above series-parallel switching switch includes a first switch, a second switch, a third switch, and a fourth switch, and When the first switch and the second switch are turned on and the third switch and the fourth switch are turned off, the series-parallel switching circuit for bidirectional power conversion is switched to a parallel operation mode, and When the first switch and the second switch are turned off and the third switch and the fourth switch are turned on, the series-parallel switching circuit for bidirectional power conversion is switched to a series operation mode, and The path of the above series-parallel switching switch does not include a first output filter capacitor and/or a second output filter capacitor, and A series-parallel switching circuit for bidirectional power conversion, characterized in that one end of the first output filter capacitor is connected to the positive terminal of each of the first bidirectional DC voltage source and the second bidirectional DC voltage source, one end of the second output filter capacitor is connected to the negative terminal of each of the first bidirectional DC voltage source and the second bidirectional DC voltage source, and the other end of the first output filter capacitor is connected to the other end of the second output filter capacitor.
In Article 1, A series-parallel switching circuit for bidirectional power conversion characterized in that when power is applied in the forward energy transfer direction to the series-parallel switching circuit for bidirectional power conversion, the soft start relay switch is turned off, and subsequently, the first bidirectional DC voltage source or the second bidirectional DC voltage source charges an internal voltage through the soft start resistor, the internal voltage includes the voltage across the first output filter capacitor and the voltage across the second output filter capacitor, and when the voltage difference across the soft start relay switch reaches a preset threshold, the soft start relay switch is turned on to complete the precharge operation.
In Paragraph 3, A series-parallel switching circuit for bidirectional power conversion characterized in that when the power supply of the series-parallel switching circuit for bidirectional power conversion is cut off, the first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit stop energy transfer, and thereafter, the soft start relay switch is turned off and an output voltage is obtained, and when the output voltage drops to a preset safe voltage range, the discharge circuit is operated to discharge the internal voltage and implement a discharge function.
In Article 2, A series-parallel switching circuit for bidirectional power conversion, characterized in that when the series-parallel switching circuit for bidirectional power conversion switches from the series operating mode to the parallel operating mode, the first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit stop energy transfer, and then perform a delay operation according to the parallel operating mode switched by the series-parallel switching switch, and after the delay operation is terminated, the energy transfer function of the first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit is started to complete the switching of the parallel operating mode.
In Article 5, A series-parallel switching circuit for bidirectional power conversion, characterized in that, in a delay operation performed according to the parallel operation mode switched by the series-parallel switching switch, the first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit are delayed for a first time after stopping energy transfer, the first switch and the second switch are turned off and delayed for a second time after the delay for the first time, the third switch and the fourth switch are turned on and delayed for a third time after the delay for the second time, and after the delay for the third time, the energy transfer function of the first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit is started to complete the switching of the parallel operation mode, wherein the first time is set according to the current duration flow time, the second time is set according to the delay time of the turn-off operation of the soft start relay switch, and the third time is set according to the delay time of the turn-on operation of the soft start relay switch.
In Article 2, A series-parallel switching circuit for bidirectional power conversion, characterized in that when the series-parallel switching circuit for bidirectional power conversion is switched from the parallel operating mode to the series operating mode, the first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit stop energy transfer, and then perform a delay operation according to the series operating mode switched by the series-parallel switching switch, and after the delay operation is terminated, the energy transfer function of the first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit is started to complete the switching of the series operating mode.
In Article 7, A series-parallel switching circuit for bidirectional power conversion, characterized in that, in a delay operation performed according to the series operation mode switched by the series-parallel switching switch, the first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit stop energy transfer and are delayed for a first time, after the delay for the first time, the third switch and the fourth switch are turned off and are delayed for a second time, after the delay for the second time, the first switch and the second switch are turned on and are delayed for a third time, and after the delay for the third time, the energy transfer function of the first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit is started and the switching of the series operation mode is completed, wherein the first time is set according to the current duration flow time, the second time is set according to the delay time of the turn-off operation of the soft start relay switch, and the third time is set according to the delay time of the turn-on operation of the soft start relay switch.
As an operating mode switching method for bidirectional power conversion, A method for switching operating modes for bidirectional power conversion, characterized by implementing switching of a serial operating mode or a parallel operating mode using a series-parallel switching circuit for bidirectional power conversion described in any one of claims 1 to 8.
As a switching power supply, A switching power supply characterized by including a series-parallel switching circuit for bidirectional power conversion as described in any one of claims 1 to 8.

Description

Series-to-parallel switching circuit for bidirectional power conversion (Related Application) This application claims priority to a Chinese patent application filed with the Chinese Intellectual Property Office on September 26, 2023, with application number 2023112438961 and title of invention "Series-Parallel Switching Circuit for Bidirectional Power Conversion," and all contents of the prior application are incorporated by reference into this application. This application belongs to the field of electrical energy conversion technology, and specifically relates to a series-parallel switching circuit for bidirectional power conversion. With the rapid development of the new energy industry and new types of batteries, electrical energy conversion modes are gradually shifting from traditional unidirectional flow to bidirectional flow, leading to increasingly diverse application scenarios for new types of electrical energy. Isolated DC/DC topologies that realize bidirectional energy flow require wider voltage gain conversion ratios and higher power densities, while simultaneously necessitating reliable input/output electrical isolation and higher conversion efficiency. Currently, to achieve the capability to handle a wide output voltage range of bidirectional DC/DC conversion circuits, a series-to-parallel conversion design is typically implemented for two bidirectional DC/DCs. Bidirectional DC/DC conversion topologies generally adopt dual active bridge circuits or bidirectional inductor-inductor-capacitor (LLC) circuits. Dual active bridge circuits and bidirectional LLC circuits belong to current source conversion topologies. When a current source conversion circuit performs series-to-parallel conversion, the output circuit must be completely isolated from the outside, and after the output capacitor voltage is discharged to 0V through a bleeder circuit, the series-to-parallel conversion and pre-charging soft-start operation are performed. This method cannot realize high-speed series-to-parallel conversion. The present application provides a series-parallel switching circuit for bidirectional power conversion to solve the problem that high-speed switching of series-parallel switching cannot be realized. In a first embodiment, the present application provides a series-parallel switching circuit for bidirectional power conversion. The series-parallel switching circuit for bidirectional power conversion comprises a first bidirectional DC voltage source and a second bidirectional DC voltage source, a first bidirectional DC/DC isolation conversion circuit and a second bidirectional DC/DC isolation conversion circuit, a series-parallel switching switch, a first output filter capacitor and a second output filter capacitor, a discharge circuit, and a soft start circuit. The first bidirectional DC voltage source and the second bidirectional DC voltage source are configured to provide a DC voltage for bidirectional power conversion, and the direction from the first bidirectional DC voltage source to the second bidirectional DC voltage source is the forward energy transfer direction. The first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit are configured to implement a bidirectional DC/DC function. The series-parallel switching switch connects the first bidirectional DC/DC isolation conversion circuit and the second bidirectional DC/DC isolation conversion circuit in series or in parallel, so that the series-parallel switching circuit for bidirectional power conversion performs switching operations in a series operation mode or a parallel operation mode. The first output filter capacitor is the output filter capacitor of the first bidirectional DC/DC isolation conversion circuit, and the second output filter capacitor is the output filter capacitor of the second bidirectional DC/DC isolation conversion circuit. When the series-parallel switching switch is switched, the voltage across the first output filter capacitor and the voltage across the second output filter capacitor do not change. The discharge circuit is configured to discharge the first output filter capacitor and the second output filter capacitor when the power to the circuit is cut off. The soft start circuit includes a soft start relay switch and a soft start resistor, and is configured to perform capacitance precharging on both the first output filter capacitor and the second output filter capacitor to maintain the voltage difference between the first bidirectional DC voltage source or the second bidirectional DC voltage source and the first output filter capacitor and the second output filter capacitor within a preset range. In the above-described embodiment and any possible implementation method, one additional implementation method is provided. The series-parallel switching switch comprises a first switch, a second switch, a third switch, and a fourth switch. When the first switch and the