Electric automobile and power battery heating system and heating method thereof

Abstract

The invention discloses an electric vehicle and a power battery heating system and method, and the method comprises the steps: enabling a motor system to enter a pulse heating mode when a pulse heating entering condition is met, carrying out the pulse heating of a power battery, and enabling a cooling liquid absorbing the heat of the motor system to enter a cooling pipeline of the power battery to heat the power battery; when the pulse heating quit condition is met, enabling the motor system to quit the pulse heating mode, stopping pulse heating of the power battery, and enabling the cooling liquid in the cooling pipeline of the power battery to stop flowing; in a pulse heating mode, enabling quadrature-axis voltage to be equal to zero, adjusting the magnitude of pulse current by controlling direct-axis voltage, generating actual pulse width modulation signals of the six power switches by superposing pulse signals. Three-phase current feedback quantity is not needed, the output pulse current is stable and small in fluctuation, the pulse heating effect of the power battery can be improved, and unexpected driving or shaking of a vehicle in the pulse heating process of the power battery is avoided.

Description

technical field [0001] The invention belongs to the technical field of power battery heating, and in particular relates to an electric vehicle and its power battery heating system and heating method. Background technique [0002] With the vigorous development of the new energy vehicle industry, the application scenarios of electric vehicles are becoming more and more extensive. In order to adapt to different usage environments, it is necessary to ensure the normal function and performance of electric vehicles in various extreme environments. However, under extremely cold conditions, due to the inherent characteristics of power batteries, their low-temperature charge and discharge capabilities will be greatly reduced, which will greatly limit the use of electric vehicles in low-temperature environments. [0003] In order to solve the above problems, it is necessary to heat the power battery in a low temperature environment. In the prior art, there are mainly two methods for h...

AI Technical Summary

Problems solved by technology

However, the current passing through the three-phase AC motor is DC current, and this phase current regulation method is not suitable for pulse heating (that is, it is not suitable for the scheme where the current passing through the three-phase AC motor is pulse current)

Because, if this phase current adjustment method is used in pulse heating, in addition to the preset direct-axis current Id and the preset quadrature-axis current Iq, a three-phase AC is required when calculating the direct-axis voltage Ud and quadrature-axis voltage Uq The three-phase current feedback of the motor, the closed-loop adjustment method with feedback will slow down the pulse current generation speed, resulting in slower heating speed; and the three-phase current feedback is unstable and fluctuates greatly, which will cause the output pulse current to be unstable and fluctuate Large, which leads to poor heating effect, and the vehicle is also prone to unexpected driving or shaking

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