Disclosure of Invention
In view of the above problems, the present invention is directed to a control system for an electric vehicle.
The purpose of the invention is realized by adopting the following technical scheme:
an electric vehicle control system is proposed, comprising: the device comprises a signal input module, a processing module and an execution module; wherein,
the signal input module is used for inputting one or more of real-time crank signals, brake crank signals, anti-theft signals and vehicle speed detection signals to the processing module;
the processing module is used for processing the received signals and sending corresponding control instructions to the execution module;
the execution module is used for controlling a motor driver of the electric vehicle to drive a motor to output corresponding driving force or reverse driving force according to the received control instruction.
In one embodiment, the signal input module is connected with a rotating handle sampling circuit of the electric vehicle to acquire a rotating handle voltage signal;
the processing module calculates corresponding motor driving force output according to the handle rotating voltage signal and generates a corresponding control instruction so as to control a motor driver of the electric vehicle to control the motor to drive the corresponding driving force.
In one implementation mode, the signal input module is connected with a brake sampling circuit of the electric vehicle to acquire a brake signal;
the processing module detects the acquired brake signal, and when the brake signal is detected to be a low level signal, the processing module calculates corresponding motor reverse driving force output according to the current speed of the electric vehicle and generates a corresponding control instruction.
In one implementation mode, the signal input module is connected with an anti-theft signal generation circuit of the electric vehicle to acquire an anti-theft signal;
the processing module detects the acquired anti-theft signal, and when the anti-theft signal is detected to be a low level signal, the processing module calculates corresponding motor reverse driving force output according to the current speed of the electric vehicle and generates a corresponding control instruction so as to control a motor driver of the electric vehicle to output the reverse driving force to achieve the effect of locking the motor.
In one embodiment, the signal input module is connected with a speed detection unit of the electric vehicle to acquire a real-time speed detection signal of the electric vehicle;
the processing module detects the acquired speed detection signal, and generates a corresponding control instruction when the speed of the electric vehicle is greater than a set limit speed so as to control the motor controller to control the motor to reduce the output of the driving force and control the electric vehicle to reduce the speed to the limit speed.
In one embodiment, the signal input module further comprises: the current sampling unit is connected with the electric vehicle and used for acquiring a current signal output by the electric vehicle storage battery when the electric vehicle storage battery works;
the processing module carries out arc detection according to the acquired current signal, generates a corresponding control instruction when detecting that a direct current arc fault occurs, and cuts off a power supply line of the storage battery of the electric vehicle by the execution module.
The invention has the beneficial effects that: the electric vehicle control system uniformly receives level signals or data acquisition signals generated by different parts of an electric vehicle and a control circuit thereof through the signal input module, processes the acquired signals through the processing module, further drives the execution module to complete corresponding instructions, controls the motor driver through a simple and efficient software control system so as to meet the requirements of different functions (such as acceleration, deceleration, theft prevention, speed limitation and the like), has strong expansibility, and can meet the requirements of the electric vehicle control system on multifunctional realization.
Detailed Description
The invention is further described in connection with the following application scenarios.
Referring to fig. 1, there is shown an electric vehicle control system comprising: a signal input module 1, a processing module 2 and an execution module 3, wherein,
the signal input module 1 is used for inputting one or more of real-time crank signals, brake crank signals, anti-theft signals and vehicle speed detection signals into the processing module 2;
the processing module 2 is used for processing the received signals and sending corresponding control instructions to the execution module 3;
the execution module 3 is used for controlling a motor driver of the electric vehicle to drive a motor to output corresponding driving force or reverse driving force according to the received control instruction.
In the above embodiment of the present invention, the signal input module 1 uniformly receives level signals or data acquisition signals generated by different components of the electric vehicle and a control circuit thereof, the processing module 2 processes the acquired signals, and further drives the execution module 3 to complete corresponding instructions, and the motor driver is controlled by developing a simple and efficient software control system to realize the requirements of different functions (such as acceleration, deceleration, theft prevention, speed limitation, etc.), and the expansibility is strong, so that the requirement of the electric vehicle control system on the realization of multiple functions can be satisfied.
In one embodiment, the processing module 2 employs a processing unit including a single chip, an MCU, and an ECU to satisfy the implementation of the above logic functions.
In one embodiment, referring to fig. 2, the signal input module 1 is connected to a handle sampling circuit of an electric vehicle to obtain a handle voltage signal;
the processing module 2 calculates corresponding motor driving force output according to the handle-rotating voltage signal and generates a corresponding control instruction so as to control a motor driver of the electric vehicle to control the motor to drive the corresponding driving force.
In order to meet the requirement of speed regulation of the electric vehicle, the signal input module 1 is connected with a handle rotating sampling circuit of the electric vehicle, the handle rotating sampling circuit rotates to the maximum rotating position from the starting position according to a handle, small-to-large handle rotating voltage signals are respectively output, the signal input module 1 inputs the real-time handle rotating voltage signals into the processing module 2, the processing module 2 obtains corresponding control instructions according to the size of the handle rotating voltage signals, and the execution module 3 controls the motor to output zero-to-maximum driving force according to the small-to-large handle rotating voltage signals.
In one embodiment, the signal input module 1 is connected with a brake sampling circuit of the electric vehicle to acquire a brake signal;
the processing module 2 detects the acquired brake signal, and when the brake signal is detected to be a low level signal, the processing module calculates corresponding motor reverse driving force output according to the current speed of the electric vehicle and generates a corresponding control instruction.
In order to meet the requirement of braking of the electric vehicle, when a user closes the brake crank, the output of the brake sampling circuit is a low level signal, meanwhile, a brake voltage signal with a corresponding magnitude is output by the brake sampling circuit according to the stress condition of the brake crank, when the IO port of the control system connected with the brake sampling circuit detects that the input is the low level, the processing module 2 further calculates the magnitude of corresponding reverse driving force according to the current vehicle speed and the brake voltage signal to generate a control instruction, and a motor driver applies corresponding direction driving force to the motor to achieve the braking effect.
In one embodiment, the signal input module 1 is connected with an anti-theft signal generating circuit of the electric vehicle to acquire an anti-theft signal;
the processing module 2 detects the acquired anti-theft signal, and when the anti-theft signal is detected to be a low level signal, the processing module calculates corresponding motor reverse driving force output according to the current speed of the electric vehicle and generates a corresponding control instruction so as to control a motor driver of the electric vehicle to output the reverse driving force to achieve the effect of locking the motor.
In order to meet the anti-theft requirement of the electric vehicle, when the anti-theft device detects that the electric vehicle has anti-theft threat, the anti-theft device sends out a low-level anti-theft signal through the anti-theft signal generating circuit, when the control system is connected to an IO port of the anti-theft device and detects that the input is low level, the processing module 2 calculates the corresponding reverse driving force according to the current vehicle speed to generate a control instruction, and the motor driver applies the corresponding square reverse driving force to the motor so as to achieve the effect of locking the motor.
In one embodiment, the signal input module 1 is connected with a speed detection unit of an electric vehicle, and acquires a real-time speed detection signal of the electric vehicle;
the processing module 2 detects the acquired vehicle speed detection signal, and when the vehicle speed of the electric vehicle is greater than a set limit speed, the processing module generates a corresponding control instruction so as to control the motor controller to control the motor to reduce the output of the driving force and control the electric vehicle to reduce the speed to the limit speed.
In order to meet the requirement of speed limit of the electric vehicle, the vehicle speed detection unit detects the current vehicle speed of the electric vehicle in real time, when the processing module 2 detects that the current vehicle speed is greater than a set limit speed, the processing module calculates corresponding reverse driving force according to the current vehicle speed and generates a control instruction, a motor driver applies corresponding square reverse driving force to the motor to achieve a speed reduction effect, and when the speed is reduced to the set limit speed, the motor is controlled to output constant driving force to enable the electric vehicle to run at a constant speed.
In one embodiment, the signal input module 1 further comprises: the current sampling unit is connected with the electric vehicle and used for acquiring a current signal output by the electric vehicle storage battery when the electric vehicle storage battery works;
the processing module 2 carries out fault arc detection according to the acquired current signal, generates a corresponding control instruction when detecting that a direct current arc fault occurs, and cuts off a power supply line of the storage battery of the electric vehicle by the execution module 3.
In one embodiment, referring to fig. 3, the current sampling unit includes a current transformer 8, and the current transformer 8 is used for collecting a current signal output by the storage battery of the electric vehicle;
the signal input module 1 includes a current signal processing unit 11;
the current signal processing unit 11 performs amplification, filtering, and AD conversion processing on the current signal acquired by the current transformer 8, converts the acquired current signal into a current digital signal, and inputs the current digital signal into the processing module 2.
Aiming at the problems that in the prior art, the contact failure, the damage of an insulating layer or other conductive properties are easily caused by long-time use of a motor and a storage battery of an electric vehicle, so that a connecting wire or a motor is easily subjected to power-on removal to generate an arc fault, the temperature is increased greatly, and the ignition accidents of the storage battery, the motor and the like can be caused if the temperature is serious; therefore, in the above embodiment, the electric vehicle control system of the present invention further detects the output current of the storage battery by setting the current sampling unit, and simultaneously performs fault arc detection on the acquired current signal by the processing module 2, and when an arc fault is detected, the circuit is cut off in time by the execution module 3, so as to ensure the operation safety of the electric vehicle. Meanwhile, the signal input module 1 is used for preprocessing the current signal acquired by the current transformer 8 and inputting the acquired current digital signal into the processing module 2, so that the processing module 2 can conveniently detect and process the current digital signal for further fault arc.
In one embodiment, the processing module 2 comprises a fault arc detection unit 21;
the fault arc detection unit 21 is used for detecting fault arc by the acquired current signal, and comprises:
1) performing frame windowing processing on the acquired current digital signal by adopting a window with a set length;
2) respectively performing wavelet decomposition on the single-frame current digital signals aiming at the single-frame current digital signals to obtain high-frequency wavelet coefficients and low-frequency wavelet coefficients of the single-frame current digital signals;
reconstructing according to the obtained high-frequency wavelet coefficient to obtain the high-frequency component of the frame current digital signal;
calculating a first detection parameter of the fault arc according to the high-frequency component of the frame current digital signal, judging according to the obtained first detection parameter, and judging whether the fault arc is a suspected arc fault signal;
3) when a certain frame of current digital signal is judged to be a suspected arc fault signal, further acquiring a next B frame of current digital signal of the frame of current digital signal, and further judging whether an arc fault occurs according to a second detection parameter of a high-frequency component of the next B frame of current digital signal and the acquired second detection parameter;
4) when the occurrence of the arc fault is detected, a control instruction is generated and sent to the execution module 3, so that the execution module 3 cuts off a power supply line of the storage battery of the electric vehicle.
In the above embodiment, a technical scheme for detecting a fault arc according to a current digital signal is provided, and since it is found that when a fault arc occurs, a large number of discrete cut-off points are generated in the current signal, so that the fluctuation range and the fluctuation rate of the high-frequency component of the current signal are increased sharply, the fault arc can be accurately reflected by using the high-frequency component contained in the current digital signal as a basis, and the occurrence of the arc fault can be accurately judged, so that the accuracy is high, and the electric vehicle control system can be facilitated to execute corresponding cut-off actions in time, and accidents are prevented.
In one embodiment, the fault arc detection unit 21 performs frame windowing on the acquired current digital signal by using a window with a set length, where the window length N is 200, the frame length is 0.2s, and the sampling frequency of the current digital signal is 1000 Hz.
In one embodiment, in the fault arc detection unit 21, for a single-frame current digital signal, performing wavelet decomposition on the single-frame current digital signal respectively includes:
performing wavelet decomposition on the single-frame current digital signal by adopting a set wavelet basis and a set decomposition layer number, wherein the adopted wavelet basis is dB1, and the decomposition layer number is J-4; acquiring high-frequency wavelet coefficients g (J, K) and low-frequency wavelet coefficients d (J, K) of the frame current digital signal, wherein g (J, K) represents a kth high-frequency wavelet coefficient of a jth layer, wherein J is 1, 2. d (j, k) represents the kth low-frequency wavelet coefficient of the jth layer;
reconstructing according to the obtained high-frequency wavelet coefficient to obtain the high-frequency component G (t) of the frame current digital signal, wherein G (t) represents the high-frequency component of the t-th frame current digital signal, and G (t) is (x)t(1),xt(2),...,xt(n),...,xt(N)), wherein xtAnd (N) represents the amplitude corresponding to the nth sampling point in the high-frequency component of the current digital signal of the t frame, and N represents the number of the sampling points of the current digital signal of each frame.
In one embodiment, the arc fault detection unit 21 further includes, after acquiring the high frequency coefficient of the single-frame current digital signal:
denoising the acquired high-frequency wavelet coefficient, which comprises the following steps:
performing threshold processing on the obtained high-frequency wavelet coefficient, wherein the adopted threshold processing function is as follows:
in the formula, g' (j, k) represents the kth high-frequency wavelet coefficient of the jth layer after threshold processing, g (j, k) represents the obtained kth high-frequency wavelet coefficient of the jth layer, and omega
1And ω
2Indicating a set first threshold and a second threshold, where ω
2=β×ω
1,β∈[0.1,0.2];
Sigma denotes the standard deviation estimate of the noise,
med (g (1)) represents the median of the high-frequency wavelet coefficients g (1, k) obtained after the wavelet decomposition of layer 1, and N represents the current digital signal of a single frameLength, α denotes the opsonization factor, where α ∈ [0.9,1.1 ]];
And reconstructing according to the high-frequency wavelet coefficient after threshold processing to obtain the high-frequency component of the frame current digital signal.
In the above embodiment, a mode is provided in which after the high-frequency wavelet coefficient is obtained, the high-frequency wavelet coefficient is first subjected to denoising processing, so that noise interference contained in the current signal can be effectively removed, and thus the accuracy of fault arc detection is improved.
Meanwhile, in the noise removal scheme, an improved threshold processing function is provided, and according to the characteristics of noise and fault arc, noise is removed, meanwhile, the traditional threshold function is prevented from adopting a 'one-knife-cut' processing mode for a small coefficient, and the characteristic information of the fault arc is kept to the maximum extent; the accuracy of fault arc detection is indirectly improved.
In one embodiment, the calculating the first detection parameter of the fault arc according to the high frequency component of the frame current digital signal in the fault arc detection unit 21 includes:
acquiring a high-frequency component G (t) of a current digital signal of a current frame;
calculating a first detection parameter of the frame current digital signal, wherein the calculation function of the first detection parameter is as follows:
in the formula, C
1(t) a first detection parameter, x, representing the current digital signal of the t-th frame
t(n) represents the magnitude of the nth sample point in the high frequency component of the current digital signal of the t-th frame,
representing each sample point in the high frequency component of the current digital signal of the t-th frameAverage value of the amplitudes, (n) represents a weight adjustment factor for the nth sample point, where
Gamma represents the set frame-edge adjustment factor, where gamma e (0, 0.28)]N represents the number of sampling points in the single-frame current digital signal;
first detection parameter C to be obtained
1(t) and set threshold
Making a comparison when
And marking the current digital signal of the t-th frame as a suspected arc fault signal.
In the above embodiment, a method for initially determining an arc fault according to the high-frequency component is provided, which reflects the fluctuation degree of the high-frequency component based on the variance of the high-frequency component of the current signal; and further considering the situation that the sampling points of the frame head and the frame tail are easy to distort after the high-frequency component is reconstructed due to the fact that the framing processing situation is considered, an improved weight adjusting factor is provided for optimizing the first detection component function, the optimized first detection parameter can accurately reflect the fluctuation characteristic of the high-frequency component of the current signal, and therefore preliminary judgment is conducted on whether the current signal has the arc fault or not.
In one embodiment, in the fault arc detection unit 21, when it is detected that the t-th frame current digital signal D (t) is a suspected arc fault signal, the following B frame current digital signal D (t +1) of the frame current digital signal is further acquired;
respectively acquiring high-frequency components G (t + B) of a current digital signal D (t + B) of a later B frame, wherein B is 1, 2.
Calculating a second detection parameter according to the obtained high-frequency component G (t + b), wherein the adopted second detection parameter obtaining function is as follows:
in the formula, C
2(t + b) a second detection parameter, C, representing the t + b frame current digital signal
1(t + b) and C
1(t) first detection parameters, x, representing the current digital signals of the t + b th frame and the t th frame, respectively
t+b(n) represents the magnitude of the nth sample point of the high frequency component of the t + b th frame current digital signal,
the average value of the amplitude values of all sampling points in the high-frequency component of the current digital signal of the t-th frame is represented, N represents the number of the sampling points in the single-frame current digital signal, and mu represents a set weight adjusting factor;
judging whether an arc fault is generated according to the acquired second detection parameters, wherein if the current digital signals D (t +1),. once, D (t + B),. once, D (t + B) of the next B frame are in the current digital signals D (t +1), D (t + B), D (t + B), the second detection parameters acquired by each frame are all larger than a set threshold value
Judging that an arc fault is generated, generating a control instruction and sending the control instruction to the execution module 3, so that the execution module 3 cuts off a power supply line of the storage battery of the electric vehicle; otherwise, continuing to detect whether the arc fault is generated based on the latest one of the current digital signal frames of the subsequent B frame which is marked as the suspected arc fault signal.
Preferably, B.epsilon.1, 3.
In other words, in one scenario, taking the frame length of each frame of current signal as an example of 20ms, in the above embodiment, when it is initially detected that an arc fault exists in a certain frame of current digital signal, it further detects the following 1-3 frames of signals, and performs comprehensive judgment by integrally combining signals collected within continuous 40ms-80ms, so as to accurately reflect the characteristics of fault arc information contained in the current signal. The reliability of arc fault detection is improved.
In the embodiment, when it is preliminarily determined that an arc fault exists in a certain frame of current digital signal, a plurality of frames of current digital signals after the certain frame of current digital signal are further detected, wherein the adopted second detection parameter determination function takes the frame of current digital signal which is preliminarily determined that the arc fault exists as a comparison basis, and when the same fault arc characteristics exist in subsequent frames of current digital signals, the generation of the arc fault is determined, so that the false detection condition caused by external noise interference can be effectively avoided, and the accuracy of fault arc detection is further improved.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be analyzed by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.