A step-down dc-dc conversion circuit for electric vehicles

Abstract

The invention relates to a step-down DC-DC conversion circuit for an electric vehicle. The step-down DC-DC conversion circuit comprises an output voltage value control circuit, the pulse width modulation signal output end of a CPU of the output voltage value control circuit is connected with the input end of an optocoupler, the output end of the optocoupler is connected with the control pulse input end of a drive module, and the drive pulse output end of the drive module is connected with grids of IGBTs. The collector of each IGBT is connected with the positive electrode of the power battery,and the load is connected between the emitter of each IGBT and the negative electrode of the power battery; and a plurality of load fly-wheel diodes which are connected in parallel are connected between the emitting electrode of each IGBT and the negative electrode of the power battery. A +5V power supply is generated by the power battery through the DC-DC converter to be used by the CPU, and a +15V power supply is generated to be used by the driving module. The circuit is further provided with an input voltage value display circuit, an output voltage setting and display circuit and an actualoutput voltage value display circuit. A low-voltage storage battery does not need to be installed, the installation space of the automobile is saved, the purchasing and battery replacing cost is saved, and operation is reliable.

Description

technical field [0001] The invention relates to a power supply circuit, in particular to a step-down DC-DC conversion circuit for electric vehicles, and belongs to the technical field of DC power supplies for electric vehicles. Background technique [0002] With the popularity of electric vehicles, the application of DC-DC control technology is becoming more and more extensive. The voltage of the power battery on the car is as high as or more than DC500V, while the rated working voltage of the air conditioner, blower, compressor, headlight, horn and other high-power automotive appliances on the electric car is DC12V or DC24V. The traditional solution for electric vehicles is to use a dedicated DC12V or DC24V battery for on-board appliances, and use a DC-DC converter to convert the high voltage of the power battery into a lower voltage to charge the battery for DC12V or DC24V on-board appliances. [0003] The traditional solution has the following deficiencies: 1. On the bas...

AI Technical Summary

Problems solved by technology

[0003] The traditional solution has the following deficiencies: 1. On the basis of high-voltage power batteries, low-voltage batteries are added, which increases the cost of purchasing and replacing batteries. The batteries need to occupy a larger installation space and increase the space of the car. load capacity

[0005] 3. The charging of the battery for on-board electrical appliances undergoes two conversions between electrical energy and chemical energy, which greatly reduces the efficiency of electricity consumption

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