Speed limiting device of electric vehicle

Abstract

The invention relates to a speed limiting device of an electric vehicle. The speed limiting device comprises a power supply device, a main control device, a speed regulating device, a motor control device, a speed collecting device and an output control device, wherein the speed collecting device is used for collecting the change speed of a motor Hall device and collecting the change speed of a motor phase line; the output control device is composed of a switch device and a driving circuit and is used for controlling the switching time of the switch device through the size of the duty ratio output by the main control device and therefore controlling the current output to the motor control device; and the power supply device supplies power for the output control device. The speed limiting device has the advantages that the accelerated speed is not calculated according to the output duty ratio, but the actual accelerated speed is directly calculated by judging the speed change value of the speed collecting device in fixed time (T), the maximum power output can be realized in a speed limiting range, and the maximum torque is achieved.

Description

technical field [0001] The invention relates to a device for an electric vehicle, in particular to a speed limiting device for an electric vehicle. Background technique [0002] At present, as a means of transportation, electric vehicles have the advantages of energy saving, environmental protection, economy and convenience. The first two points are the needs of the country, and the last two points are the needs of middle and low-level consumers. At present, electric vehicles are implemented in accordance with the management norms of non-motor vehicles, and enjoy certain preferential treatment like bicycles. It is precisely because of the loose policy that the number of electric vehicles in my country has grown too fast, and the driving speed of electric vehicles is also getting faster and faster. Some models even exceed the speed of motorcycles. The safety accidents of electric vehicles have also increased rapidly. Considering the existence of these comprehensive problems...

AI Technical Summary

Problems solved by technology

Considering the existence of these comprehensive problems, the country cannot fundamentally limit the development of electric vehicles, so it gradually introduces the national speed limit standard for electric vehicles. The current speed limit for electric bicycles is 20 km / h

However, most of the factory speeds of electric vehicles currently produced exceed this speed limit standard. If you want to meet the national standard, you must use the speed limit function. However, the speed limit method currently used is simply to limit the single output duty cycle ( PWM)

[0003] Although this method can limit the speed, it has the following disadvantages: First, for different vehicles and motors, the speed limit varies greatly

As a result, although the speed limit function is available, the speed limit value is different due to different models.

The second is that in the case of speed limitation, the output power of the motor is also limited, and the maximum torque cannot be provided when the motor is at a low speed, especially when the motor starts and works with a heavy load. This disadvantage is more obvious. If you use this method to Limiting the speed of electric vehicles becomes a burden for users

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