JPH0447524B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electric vehicle slipping/sliding detection device that detects slipping/slipping of drive wheels in an electric vehicle.

[Technical background of the invention and its problems] In general, in order to prevent the drive wheels of electric vehicles from slipping and sliding, electric vehicles are equipped with a slipping and skidding detection device to control the torque of the drive wheels and to prevent the drive wheels from slipping and sliding. A predetermined adhesive force is obtained between the two. Slip/skid detection detects the rate of change ΔFR of the rotational frequency of the drive wheel based on a signal from a pulse generator installed on the rotating shaft of the electric motor that drives the drive wheel. Rate of change of rotational frequency △
When FR is detected, it is compared with the slipping detection level or skidding detection level. When this rate of change ΔFR remains greater than the detection level for longer than a predetermined time T, it is determined that the drive wheels are slipping or skidding, and slipping/slipping detection is performed.

The slipping/skidding detection level and the predetermined time T are constant values at high speeds and low speeds, and the values are adjusted to values suitable for driving in the low speed range where the torque generated by the drive wheels is large. When driving at high speeds, the vibration of the truck becomes more pronounced than when driving at low speeds.
The rate of change ΔFR of the rotational frequency of the drive wheels fluctuates more rapidly than at low speeds and takes on a large value. Therefore, a false detection may be made even though the drive wheels are not actually spinning or sliding. If a false detection is made, the torque of the drive wheel is controlled to obtain a predetermined adhesive force between the drive wheel and the rail.
During acceleration, the riding comfort deteriorates, and particularly during regeneration control, there arises a problem that sufficient braking force cannot be obtained.

[Object of the Invention] The present invention provides a slipping/slipping detection device for an electric vehicle that improves the accuracy of detecting slipping/slipping of the drive wheels of an electric vehicle and eliminates deterioration of riding comfort of the electric car due to false detection. With the goal.

[Summary of the Invention] The present invention provides a calculation stage for calculating the rotational frequency change rate of the drive wheels from the rotational speed of the drive wheels of the electric vehicle, and a detection level of the rotation frequency change rate of the drive wheels according to the speed of the electric vehicle. and a delay time setting means that outputs a delay time value corresponding to the speed of the electric vehicle, and the rotation frequency change rate value output from the calculation means is output from the detection level setting means. When the detection level is exceeded, a signal is output from the comparing means, and when this signal from the comparing means is output continuously for more than the delay time set by the delay time setting means, the slipping/sliding detection means outputs a slipping/slipping signal. This configuration has high detection accuracy,
It is characterized by the ability to prevent deterioration of the riding comfort of electric vehicles due to false detection.

[Embodiments of the Invention] Examples of the present invention will be described in detail with reference to FIG. FIG. 1 is a block diagram of an embodiment of the slipping/skidding detection device of the present invention and a block diagram of a peripheral control device.

The main controller 2 is comprised of a variable voltage, variable frequency inverter and controls the speed of the main motor 3. The main electric motor 3 drives the drive wheels 4 of the electric vehicle. A pulse generator 6 that generates pulses according to rotation is connected to the rotating shaft of the main motor 3. The output of the pulse generator 6 is sent to the slip/slip detection device 1 via the speed detector 7.
It is input to the detection level calculator 8 and the delay time calculator 9, and the rotation frequency change rate calculator 10
is input. Here, the detection level calculator 8 and the delay time calculator 9 are a detection level setting means and a delay time setting means, respectively, and the rotation frequency change rate calculator 10 is a calculation means. The rotational frequency change rate calculator 10 is composed of a pulse counter 11, a sampling hold circuit 12, and a rate of change calculator 13. The rotation frequency change rate calculator 10 and the detection level calculator 8 are connected to a comparator 14. The comparator 14 and the delay time calculator 9 are connected to a delay circuit 15. Here, the delay circuit 15 is a slipping/skidding detection means. The output of the delay circuit 15 is input to the main controller 2 as a slipping/skidding detection signal.

The operation of the embodiment with the above configuration will be explained. A pulse generator 6 provided on the rotating shaft of the main electric motor 3 generates pulse signals according to the rotation of the drive wheels 4 at any time. The pulse counter 11 outputs a rotation frequency value by counting the number of pulses per unit time of the pulse signal output by the pulse generator 6. The sampling and holding rotation 12 inputs the output signal of the pulse counter 11, and after a predetermined time (sampling time) outputs the same signal as at the time of input. In the computing unit 13, the pulse counter 11
The rate of change ΔFR is calculated from the output value FR(ST) of the sampling hold circuit 12 and the output value FR(ST) of the sampling hold circuit 12 using the following equation and is output.

△FR=FR−FR(ST)/ST (ST: sampling time) The pulse signal output from the pulse generator 6 is input to the speed detector 7, and the speed detector 7 detects the speed from the pulse signal and calculates the speed. Output a signal. This speed signal is input to a detection level calculator 8 and a delay time calculator 9. Based on the speed signal, the detection level calculator 8 outputs a slip detection level FRD when the electric vehicle is running under power, and outputs a skid detection level SRD when the electric vehicle is under regenerative braking. Similarly, the delay time calculator 9 outputs a delay time value based on the speed signal.

Here, the slipping and skidding detection levels FRD, SRD
is based on the electric vehicle's running slope and vehicle weight.
It is set by finding the maximum acceleration at that slope and multiplying it by the empirical value. For example, a value of 1.5 is used for experience points.

Further, the delay time value is provided to prevent false detection, and is set to the time required for several signals from the comparator 14 to arrive. For example, if the signal from the comparator 14 is output at intervals of 2 seconds, the delay time is set to 10 seconds, which is the time it takes to obtain the signal five times.

Here, as the speed of the electric vehicle increases, the prevalence of noise in the delay time value increases, so it is necessary to increase the delay time value according to the speed to eliminate false detection. Therefore, both the detection level calculator 8 and the delay time calculator 9 increase the detection level and delay time value, which are output signals, as the speed increases, in response to the input of the speed signal from the speed detector 7.

An example of this relationship is shown in FIGS. 2a and 2b. Here, FIGS. 2a and 2b are output waveform diagrams of the detection level calculator 8 and the delay time calculator 9 for speed.

The comparator 14 compares the rate of change △FR of the rotational frequency with the output signal of the detection level calculator 8 and determines the rate of change △
Outputs a 'H' level signal when FR becomes large. Next, the delay circuit 15 receives the signal from the comparator 14.
When the input continues to be at the 'H' level for more than the delay time by the delay time calculator 9 after the H' level signal is input, the 'H' level signal is output, and then the signal from the comparator 14 is output. Keep the output signal at 'H' level until it reaches 'L' level. Delay circuit 1
The 'H' level signal outputted by the motor 5 is given to the main controller 2 as a slipping/slipping detection signal SL. When the main controller 2 receives the detection signal SL, it performs control to reduce the torque generated by the main motor 3.

The relationship between the rotational frequency change rate ΔFR and the slipping/skidding detection signal SL will be explained using FIG. Here, Fig. 3 a shows the rate of change of rotational frequency with respect to time △
In the output waveform diagram of the FR, b is an output waveform diagram of the slipping/skidding detection signal SL during low-speed operation versus time, and c is an output waveform diagram of the slipping/skidding detection signal SL during high-speed operation versus time.

In FIG. 3a, HFRD and HSRD are the outputs of the detection level calculator 8, and are the slip detection level and skid detection level during high-speed operation. These slipping/skidding detection levels HFRD and HSRD are larger values than the detection levels FRD and SRD at low speeds. Figure 3b shows the slipping/sliding detection signal SL during low-speed operation. In the figure, TA is the output value of the delay time calculator 9, and is a value during low-speed operation. At time t ₁ , the detection levels FRD and SRD are exceeded, and even after time TA, the detection level is still above the detection level, so the detection signal SL is output, and the rate of change △FR continues to be above the detection level from time t ₂ to t _3. The detection signal SL continues to be output until Similarly, from time t ₆ to t ₉ , the detection signal
SL is output.

Next, high-speed operation will be explained. Figure 3c shows the slipping/slipping detection signal SL during high-speed operation. In the figure, TB is the output value of the delay time calculator 9, which is a value greater than TA at low speed, which is the value at high speed operation. At time t ₁ , the rate of change △FR is the detection level
Although it exceeds HFRD and HSRD, it falls below the detection level again within the delay time TB, so the detection signal SL is not output. Similarly, the detection level at time t ₅
Even after HFRD and HSRD have been exceeded and the delay time TB has passed, the detection signal SL is output because the detection level is higher than the detection level, and the detection signal SL is output from time t ₇ to t ₈ in order for the rate of change △FR to continue to be higher than the detection level. is output. During high-speed operation, the detection level and delay time are set to larger values than during low-speed operation to prevent false detection due to noise, so the detection signal SL is not output at time _t3 in FIG. 3c.

In other words, conventionally, the detection level and delay time are constant with respect to speed, so the third
A false detection is made between time t ₂ and t ₃ in Figure c. However, if the detection level and delay time are variable depending on the speed, false detection will not occur at high speeds.

In addition, in the above embodiment, the slip detection level and the skid detection level were explained as the same value, but
These are independent values and differ depending on the electric vehicle.

[Effects of the Invention] According to the present invention, by using the detection level of the rotational frequency change rate of the driving wheels according to the vehicle speed of an electric vehicle and the delay time value according to the vehicle speed, slipping and skidding corresponding to the speed can be prevented. Since a detection signal can be obtained, detection accuracy is high, and it is possible to prevent deterioration of the riding comfort of electric vehicles due to false detection.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the electric vehicle slipping/skidding detection device of the present invention and a block diagram of the peripheral control device, and Fig. 2 a and b are the outputs of the detection level calculator and delay time calculator for speed. FIG. 3A shows an output waveform diagram of the rotational speed change rate of the driving wheels with respect to time, and FIG. 3B and C show output waveform diagrams of the slipping/skidding detection signal with respect to time during low-speed operation and high-speed operation, respectively. DESCRIPTION OF SYMBOLS 1... Slip/slide detection device, 7... Speed detector, 8... Detection level calculator, 9... Delay time calculator, 10... Rotation frequency change rate calculator, 11...
...Pulse counter, 12...Sampling hold circuit, 13...Rate of change calculator, 14...Comparator, 15...Delay circuit, SL...Slip/skid detection signal, FRD...Slip detection level at low speed, SRD
...Slippage detection level at low speeds, HFRD...Slippage detection level at high speeds, HSRD...Slippage detection level at high speeds, TA...Delay time at low speeds, TB...
...Delay time at high speed.

Claims (1)

[Scope of Claims] 1. Calculating means 10 for calculating the rate of change in the rotational frequency of the drive wheels from the rotational speed of the drive wheels of the electric vehicle; and detection of the rate of change in the rotational frequency of the drive wheels according to the speed of the electric vehicle. detection level setting means 8 for outputting a level; delay time setting means 9 for outputting a delay time value according to the speed of the electric vehicle; and the rotation frequency change rate output from the calculation means 10 for setting the detection level. a comparing means 14 for outputting a signal when the rotational frequency change rate outputted from the means 8 exceeds a detection level; and the signal from the comparing means 14 is longer than the delay time set by the delay time setting means 9; A slipping/skidding detection device for an electric vehicle, comprising a slipping/skidding detection means 15 that outputs a slipping/skidding signal when the signal is continuously output.