A control method for multi-channel parallel full-bridge llc converters in a cascaded power system

A technology of power supply system and control method, which is applied in the direction of adjusting electric variables, control/regulation system, converting DC power input to DC power output, etc. It can solve the problem of uneven heat distribution of system circulation, reduce circulation and realize LLC parallel connection The effect of current sharing, reducing voltage and current impact

Active Publication Date: 2017-12-29
TIANJIN RES INST OF ELECTRIC SCI +1
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0005] Third, in order to expand the power level, when the LLC converters are connected in parallel, due to the differences in the parameters of each channel, there will be certain differences in the inductor current on each LLC converter, resulting in circulating currents or uneven heat distribution in the system.
This is quite detrimental to the entire DC cascaded power system

Method used

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  • A control method for multi-channel parallel full-bridge llc converters in a cascaded power system
  • A control method for multi-channel parallel full-bridge llc converters in a cascaded power system
  • A control method for multi-channel parallel full-bridge llc converters in a cascaded power system

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Embodiment Construction

[0069] The present invention will be further described in detail below in conjunction with the accompanying drawings and through specific embodiments. The following embodiments are only descriptive, not restrictive, and cannot limit the protection scope of the present invention.

[0070] A control method for multi-channel parallel full-bridge LLC converters in a cascaded power system, the structure of the cascaded power system involved in this embodiment is as follows figure 1 As shown, the front-stage converter, LLC, and rear-stage converter are sequentially connected to form a three-stage cascaded structure, which converts the front-stage DC bus voltage into the rear-stage DC bus voltage.

[0071] The specific structure of the pre-converter is that the energy storage device is connected in series on one side of the bidirectional DC-DC converter, and multiple LLC circuits are connected in parallel on the other side of the bidirectional DC-DC converter; in the cascaded power su...

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Abstract

The invention relates to a control method for a multi-way parallel full-bridge LLC converter in a cascading power supply system. The cascading power supply system employed in the method comprises a pre-stage converter, LLCs, and a post-stage converter, wherein the pre-stage converter, the LLCs and the post-stage converter are sequentially connected to form a three-stage cascading structure. An energy storage device of the pre-stage converter is located at one side of a two-way DC-DC converter, and the other side of the two-way DC-DC converter is in parallel connection with a plurality of LLCs which are connected to one side of a three-phase inverter of the post-stage converter in a parallel manner. The other side of the three-phase inverter is connected with a filter, and the filter is connected with a power grid. In a full-load range, the invention proposes a complete voltage control and current-sharing scheme, and the method enables the LLCs to be capable of achieving the voltage control of a DC bus under the conditions of no load and heavy load.

Description

technical field [0001] The invention belongs to the field of cascaded power supply systems, and relates to a control method for multi-channel parallel full-bridge LLC converters in the cascaded power supply system. Background technique [0002] The cascaded power supply system connects multiple power supply subsystems in a cascaded form to achieve multi-level conversion. It has been widely used in distributed power generation and electric vehicles in recent years. Taking the household photovoltaic power generation system as an example, the front stage adopts the Boost circuit to control the photovoltaic by MPPT, and the latter stage uses a high-frequency isolated DC-DC converter to provide electrical isolation for the system, and to increase the DC bus voltage, and finally through the inverter Realize grid-connected operation. As we all know, the LLC resonant high-frequency isolated DC-DC converter has extremely high efficiency and power density, as well as a wider gain ran...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M3/335
Inventor 刘江华董钺贺永鹏温金鑫邱晗伍丰林楚子林
Owner TIANJIN RES INST OF ELECTRIC SCI
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