LLC (inductor-inductor-capacitance) resonant DC-DC (Direct Current-Direct Current) power supply capable of changing resonance frequency by changing capacitance

Abstract

The invention relates to an LLC (inductor-inductor-capacitance) resonant DC-DC (Direct Current-Direct Current) power supply capable of changing resonance frequency by changing capacitance. The LLC resonant DC-DC power supply comprises an input circuit, an electronic switch, an LLC resonant circuit, a high-frequency transformer circuit and an output circuit; the LLC resonant circuit comprises a first inductance coil, a first capacitor and a second inductance coil, as well as a voltage / current sensor circuit and a programmable single chip computer; the voltage / current sensor circuit comprises a voltage sensor and a current sensor; the LLC resonant circuit also comprises a second VMOS (Vertical Metal Oxide Semiconductor) tube and a second capacitor; and the second VMOS tube and the second capacitor are serially connected and then connected on two ends of the first capacitor in parallel. Through the invention, the technical problem of incapability of the adjustment of resonance frequency according to the change of a load of the power supply in the traditional power supply for a vehicle is solved. Through the invention, the system is provided with two resonance points, then the power supply can work under different resonance frequencies in different loads and the frequency of the system during the adjustment deviates a little from the resonance points, so that the work efficiency of the DC-DC power supply is improved.

Description

technical field [0001] The invention relates to an LLC resonant DC-DC conversion power supply for vehicles. Background technique [0002] At present, the common vehicle LLC resonant DC-DC power supply in China adjusts the output voltage and current by adjusting the oscillation frequency of the LLC resonant circuit to deviate from the resonance point under the premise of a fixed 50% duty cycle. When the vehicle is working during the day, because the lighting system does not work, only the fuel pump and nozzle system, vehicle control computer and various sensor systems, booster pump system, door and window glass, wiper, heating and cooling systems work, and the required power is 200W About, when the night lighting system works, the required power increases to about 800W. Therefore, this method does not solve the situation that the load of the vehicle power supply varies greatly but is relatively stable, so the power supply system cannot always work in the optimal work efficie...

AI Technical Summary

Problems solved by technology

[0003] The object of the present invention is to provide a LLC resonant DC-DC power supply that can change the resonant frequency by changing the capacitance controlled by a single-chip microcomputer, which solves the problem that the existing automotive DC-DC power supply cannot adjust the LLC resonant frequency according to the needs of power supply load changes question

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