A High Efficiency Parallel llc Resonant Converter with Current Sharing Characteristics

Abstract

The invention relates to a high efficiency paralleled LLC resonant converter with current sharing characteristics; the high efficiency parallel LLC resonant converter comprises an input DC power supply Uin, a transformer T1, a transformer T2, coupling inductors Lr1 and Lr2, a resonant capacitor Cr1, a resonant capacitor Cr2, a first power MOS switch tube Q1 and a parasitic diode D1 and a parasitic capacitor C1 thereof, a second power MOS switch tube Q2 and a parasitic diode D2 and a parasitic capacitor C2 thereof, a third power MOS switch tube Q3 and a parasitic diode D3 and a parasitic capacitor C3 thereof, a fourth power MOS switch tube Q4 and a parasitic diode D4 and a parasitic capacitor C4 thereof, a first power diode Ds1, a second power diode Ds2, a third power diode Ds3, a fourth power diode Ds4, a first output capacitor Co, and a load Rload. The two LLC half-bridge resonance converters are connected in parallel, so resonant capacitance sharing and resonance inductance coupling can be realized, thus reducing current sharing characteristic error source, and realizing current sharing, high efficiency, high power density, and low voltage heavy current functions.

Description

technical field [0001] The invention relates to the design field of electric vehicle chargers and communication power supplies (low voltage and high current), in particular to a high-efficiency parallel LLC resonant converter with current sharing characteristics. Background technique [0002] With the increasingly serious energy and environmental problems, electric vehicles are becoming more and more popular, and the use of electric vehicles must require a good performance, efficient and reliable battery charger. At present, the battery charging methods mainly include constant voltage charging, constant current charging, constant voltage and constant current charging, pulse charging, etc. Among them, the constant voltage and constant current charging method is the best for maintaining battery performance, and is not prone to problems such as overcharging and undercharging. Therefore, the service life of the battery can be effectively extended. Common charging topologies inc...

AI Technical Summary

Problems solved by technology

However, in the case of high-power, low-voltage and high-current output of the single-stage half-bridge LLC resonant converter, the current stress of the power MOS switch tube and the transformer is large. For the transformer, it is not conducive to the heat dissipation, winding and power density of the transformer. ; The existing common solution is to connect the half-bridge LLC resonant converter in parallel to reduce the current stress of the power MOS switch tube and the transformer and improve the efficiency

However, due to the inevitable inconsistency of the parameters of the parallel modules, there is a current sharing problem among the parallel modules; the current common solution to the current sharing problem is either to add power devices to assist current sharing, or to add a current sharing control strategy

The former will inevitably lead to an increase in the cost of the converter and is not conducive to the improvement of efficiency, and the latter will make the control strategy complicated

Images