Isolation three-port DC-DC converter

Abstract

The invention discloses an isolation three-port DC-DC converter. The isolation three-port DC-DC converter comprises a three-winding transformer, a DC-isolation capacitor, two full-bridge circuits, a full-wave rectification circuit and two LC resonant cavities, wherein the two LC resonant cavities respectively comprises a first resonant inductor, a first resonant capacitor, a second resonant inductor and a second resonant capacitor, a DC bus-side winding is connected with a DC bus port by the DC-isolation capacitor and a first full-bridge circuit, a high-voltage battery-side winding is connected with a high-voltage battery port by the first resonant inductor, the first resonant capacitor and a second full-bridge circuit, and a low-voltage battery-side winding is connected with a low-voltagebattery port by the second resonant inductor, the second resonant capacitor and the full-wave rectification circuit. The isolation three-port DC-DC converter employs a three-winding structure, the numbers of rectification diodes and transformers are reduced, the power loss is reduced, and the circuit conversion efficiency is improved.

Description

technical field [0001] The invention belongs to the field of on-board chargers for electric vehicles, in particular to an isolated three-port DC-DC converter. Background technique [0002] Electric vehicles have attracted a lot of attention because the use of electric vehicle chargers reduces fuel usage and greenhouse gas emissions. Electric vehicle chargers are divided into two types: on-board chargers and off-board chargers, and support one-way or two-way power flow. The off-board charger can be designed as a high-power fast charging system because it is not limited by size and weight. The input of the off-board charger is 380V AC, and the output is a certain range of DC. The charging power ranges from tens of kilowatts to hundreds of kilowatts, and the charging time is 10 minutes. The DC fast charging system of off-board chargers has a large impact on the power grid, which will cause voltage fluctuations in the public power grid and generate harmonic hazards. The requi...

AI Technical Summary

Problems solved by technology

[0004] Generally speaking, the topology of a typical electric vehicle on-board charger with unidirectional power flow is that the DC bus charges the high-voltage battery through the first-stage DC-DC converter, and the high-voltage battery charges the high-voltage battery through the second-stage step-down DC-DC converter. For low-voltage battery charging, if both DC-DC converters adopt full-bridge structure and full-wave rectifier bridge structure, a total of 8 controllable power switches, 8 rectifier diodes and 2 transformers will be used, and the circuit efficiency is low

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