Hybrid fuzzy braking method for brushless direct-current motor of electric vehicle

Abstract

The invention discloses a hybrid fuzzy braking method for a brushless direct-current motor of an electric vehicle. The hybrid fuzzy braking method is used for performing braking control for the motor when a braking signal of the electric vehicle is valid, and includes detecting the rotational speed of the motor by the aid of Hall signals; judging whether the detected rotational speed of the motor is higher than a set rotational speed or not so as to determine a braking mode; adopting a mechanical braking mode if the rotational speed of the motor is lower than or equal to the set rotational speed; and adopting a hybrid braking mode combining a mechanical braking function with an energy feedback braking function if the rotational speed of the motor is higher than the set rotational speed, and disabling the energy feedback braking function while only keeping the mechanical braking function when the rotational speed of the motor is lower than the set rotational speed in a hybrid braking procedure. A self-tuning fuzzy PID (proportional integral differential) control algorithm is adopted to realize the energy feedback braking function of the hybrid braking mode, so that feedback current and pumping voltage keep lower than set values and are close to the set values to the greatest extent. The hybrid fuzzy braking method has the advantages that motor braking and energy feedback effects can be guaranteed in a braking procedure of the electric vehicle, and a driving circuit is safe.

Description

Technical field

[0001] The present invention relates to the field of electric vehicles, in particular to a brushless DC motor braking technology for electric vehicles. Background technique

[0002] As a new type of transportation, electric vehicles have a series of advantages such as green, environmental protection, energy saving, low noise, compactness, flexibility, and moderate price, and they have been widely used.

[0003] Electric vehicles are generally driven by brushless DC motors. There are usually mechanical brakes and electrical brakes to brake the brushless DC motors of electric vehicles. Among them, the electrical brakes are divided into reverse braking and energy feedback braking. Neither mechanical braking nor electrical reverse braking returns energy to the power source, which reduces the efficiency of energy use and is not conducive to energy saving and environmental protection. With the enhancement of energy conservation, emission reduction and environmental prot...

Examples

Embodiment Construction

[0015] In order to deepen the explanation of the present invention, the present invention will be described in further detail below in conjunction with the accompanying drawings. This embodiment is only used to explain the present invention and does not constitute a limitation on the protection scope of the present invention.

[0016] The braking method of a brushless DC motor for an electric vehicle according to the present invention has specific implementation steps as follows:

[0017] 1. Such as figure 1 As shown, VT1~VT6 are driving power tubes. The motor has 3 states in one cycle, and the phase changes every 120°. Therefore, only 3 steps are needed to define the phase sequence of driving the power tube when the energy is fed back to the brake motor: first step, Turn on VT4, turn off VT6, VT2; the second step, Turn on VT6, turn off VT4, VT2; the third step, Turn on VT2, turn off VT4, VT6; then according to the position signal of the Hall element, combined with the defined ph...

Technical field

[0001] The present invention relates to the field of electric vehicles, in particular to a brushless DC motor braking technology for electric vehicles. Background technique

[0002] As a new type of transportation, electric vehicles have a series of advantages such as green, environmental protection, energy saving, low noise, compactness, flexibility, and moderate price, and they have been widely used.

[0003] Electric vehicles are generally driven by brushless DC motors. There are usually mechanical brakes and electrical brakes to brake the brushless DC motors of electric vehicles. Among them, the electrical brakes are divided into reverse braking and energy feedback braking. Neither mechanical braking nor electrical reverse braking returns energy to the power source, which reduces the efficiency of energy use and is not conducive to energy saving and environmental protection. With the enhancement of energy conservation, emission reduction and environmental prot...

Examples

Embodiment Construction

[0015] In order to deepen the explanation of the present invention, the present invention will be described in further detail below in conjunction with the accompanying drawings. This embodiment is only used to explain the present invention and does not constitute a limitation on the protection scope of the present invention.

[0016] The braking method of a brushless DC motor for an electric vehicle according to the present invention has specific implementation steps as follows:

[0017] 1. Such as figure 1 As shown, VT1~VT6 are driving power tubes. The motor has 3 states in one cycle, and the phase changes every 120°. Therefore, only 3 steps are needed to define the phase sequence of driving the power tube when the energy is fed back to the brake motor: first step, Turn on VT4, turn off VT6, VT2; the second step, Turn on VT6, turn off VT4, VT2; the third step, Turn on VT2, turn off VT4, VT6; then according to the position signal of the Hall element, combined with the defined ph...

Images