JPH0721043Y2 - Braking control device for electric vehicle - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a braking control device for an electric vehicle, and in particular, drives a mechanical braking means and an electrical braking means for braking, which are attached to a traveling motor. The present invention relates to a braking control device for an electric vehicle to be controlled.

[Conventional technology]

Generally, in a braking device for an electric vehicle that uses a motor as a drive source for traveling, a mechanical braking unit (for example, an electromagnetic brake) that mechanically acts directly on the drive shaft of the motor to brake the drive shaft of the motor and the power generation of the motor itself. Braking means (electrical braking means)
Many are equipped with and used together.

In such a braking device, since the mechanical braking means has a delay in response time, first, immediately after the braking command, the power generation braking means is activated to apply the braking, and thereafter the mechanical braking means participates in the braking. The method of waiting is adopted as the braking control method, whereby the braking action is performed quickly.

Further, when the mechanical braking means described above is applied to the braking, sufficient braking can be performed only by the mechanical braking means, and therefore, a structure configured to stop the operation of the dynamic braking means is often used, As a result, it is possible to prevent the consumption of the battery required for operating the power generation braking means for a long time, thereby saving energy.

[Problems to be solved by the invention]

However, in the above-mentioned conventional technique, the dynamic braking of the motor is operated only during the time corresponding to the operation delay time of the mechanical braking means such as the electromagnetic brake, and then the dynamic braking means is stopped. If some abnormality occurs in the mechanical braking means such as the electromagnetic brake and it does not operate, the braking of the electric vehicle cannot be switched from the dynamic braking to the mechanical braking, and the braking of the electric vehicle cannot be performed. There was the inconvenience of causing trouble.

[Purpose of device]

The present invention improves the disadvantages of the conventional example, and effectively stops the runaway of the electric vehicle when the mechanical braking means and the dynamic braking means are provided side by side even when the mechanical braking means does not operate sufficiently. Alternatively, it is an object of the present invention to provide a braking control device for an electric vehicle that can be suppressed.

[Means for solving problems]

According to the present invention, a dynamic braking circuit section 12 which is energized by a predetermined stop signal to set the traveling motor 2 in a dynamic braking state, and an electromagnetic pre-installed in the traveling motor 2 which operates after receiving the stop signal. A switching control unit 14 for starting and controlling the brake 16,
After the start control of the electromagnetic brake 16 by the switching control unit 14 is started after a lapse of a predetermined time t ₂ , a power generation braking interruption control unit 18 for canceling the braking control operation of the drive motor 2 of the power generation braking circuit unit 12 is provided. I have it. Then, the traveling motor 2 is equipped with speed detecting means 20 for detecting the rotation speed of the traveling motor 2, and a predetermined time after the braking control operation of the traveling braking motor 2 of the dynamic braking circuit section 12 is released. It operates when the rotation detection signal of the traveling motor 2 is detected by the speed detection means 20 after the passage of Δα ', eliminates the release operation of the dynamic braking interruption control section 18, and resets the dynamic braking circuit section 12 to the operating state. The regenerative braking control unit 22 is installed side by side with the dynamic braking interruption control unit 18. This aims to achieve the above-mentioned object.

[Action]

The stop signal from the operator causes the electric motor braking means and the mechanical braking means to act on the traveling motor for braking. In this case, the electromagnetic brake, which is the mechanical braking means, generally has a longer mechanical operation delay time. Therefore, only the dynamic braking means operates for the first predetermined time. Then, when the predetermined time elapses, the mechanical braking means also participates in the braking operation, but in this case, from the viewpoint of power saving, the operation of the dynamic braking means is automatically interrupted by the dynamic braking interruption control section. There is.

On the other hand, the rotation speed of the traveling motor is constantly detected by the speed detection means, and if the motor is still rotating even when the predetermined braking is applied, it is assumed that the electromagnetic brake is not operating properly for some reason. The operation of the regenerative braking control unit is stopped by the action of the regenerative braking control unit, and the braking by the dynamic braking unit is controlled again. As a result, even if the electromagnetic brake fails and does not operate, it is possible to reliably avoid a situation where the braking means is completely lost and the electric vehicle runs out of control.

[Example of device]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 3.

First, in FIG. 1, reference numeral 2 indicates a traveling motor that drives an electric vehicle, and reference numeral 4 indicates a braking control device that controls the traveling motor 2. Further, reference numeral 6 indicates a motor drive unit when the motor 2 is running. Reference numeral 7 indicates a battery for power supply.

Among them, the braking control device 4 includes a variable resistor 8 that variably sets an output level of an operation signal in association with an accelerator lever (not shown) operated by an operator, and an operation signal O _a from the variable resistor 8. In response to this, the comparison judgment unit 10 for making a comparison judgment as to whether the signal is a traveling signal or a stop signal, and the ratio judgment unit when the comparison judgment unit 10 judges that the signal is a stop signal.
The dynamic braking circuit section 12 for dynamic braking that is activated by the output signal from 10 and the operation signal O _a from the variable resistor 8 are compared to determine whether the signal is a running signal or a stop signal. And a switching control section (14) for switching and setting an electromagnetic brake (16) as a mechanical braking means for the traveling motor, which is preliminarily equipped when the determination is a stop signal, to an operating state. In addition, in the braking control device 4, the switching control unit 14
After a predetermined time t _{1 when the} electromagnetic brake 16 is actuated, the mechanical delay with respect to the motor 2 described above is performed (after a lapse of this time t ₁ when the time delay until the electromagnetic brake 16 actually functions is t ₁ ). You can apply the brakes.

Further, the braking control device 4 includes the above-mentioned electromagnetic brake.
After the lapse of t ₂ seconds (= t ₁ + Δα) from the start of the operation of 16, the dynamic braking suspension control unit 18 that outputs a signal that suspends the operation of the dynamic braking circuit unit 12, and the speed detection unit 20 that detects the rotation speed of the motor 2 And t ₃ seconds (= t ₂ + Δ
When the speed detection means 20 detects the rotation of the motor 2 after the passage of α '), it is determined that the electromagnetic brake 16 has an abnormality, and the regenerative braking control for stopping the operation of the power generation braking interruption control section 18 and reactivating the power generation braking means is performed. It has a section 22.

This will be described in more detail.

As described above, the variable resistor 8 outputs the operation signal Oa (see FIG. 2 (a)) corresponding to the accelerator opening. The operation signal Oa is applied to the non-inverting input terminals of the comparator 24 in the comparison and judgment section 10 and the comparator 26 in the switching control section 14.

Among these, a sawtooth wave WS (see FIG. 2A) of a predetermined frequency generated from the sawtooth wave generator 28 is applied to the inverting input terminal of the comparator 24. And the comparator
The output signal S _{1 of} 24 reaches the motor drive unit 6 and is passed through a non-inverting buffer amplifier 30 to switch transistors.
Applied to 32 bases. Further, the output signal S ₁ reaches the dynamic braking circuit section 12, and is applied to the base of the switching transistor 36 via the inverting buffer amplifier 34.

Therefore, during the period when the operation signal Oa is larger than the sawtooth wave signal WS, the signal S ₁ from the comparison and determination section 10 becomes a logic high level (H), and the transistor 32 in the motor drive section 6 is turned on. The transistor 38 connected to is turned on. As a result, the switching transistor 40 provided in series with the motor 2 is turned on as shown in the figure (see FIG. 2 (b)), so that power is supplied from the battery 7 to the motor 2 and the motor 2 Rotate. Here, in this state, since the transistor 36 in the dynamic braking circuit unit 12 is turned off, a switching transistor provided in parallel with the motor 2 and used for dynamic braking.
42 is in the off state (see FIG. 2 (c)).

Further, in a period in which the operation signal Oa is smaller than the sawtooth wave signal WS, the signal S ₁ becomes the logic L level, the transistor 36 in the dynamic braking circuit unit 12 is turned on, and thus the transistor 42 is turned on (FIG. 2). (See (c)). Therefore, the counter electromotive force generated in the motor 2 at that time is supplied to the motor 2 through the transistor 42, and thereby the motor 2 is dynamically braked. In this case, the motor drive unit 6
Is inactive.

By the way, in the motor drive unit 6, the magnitude of the current supplied to the motor 2 is detected by the shunt resistor 44 connected in series to the motor 2. Then, the detected value is compared with the reference value VR by the comparator 46 or the like configured as shown. Therefore, when the detected value exceeds the reference value VR, the output of the comparator 46 falls to the logic low level (L), which turns off the transistor 32 and stops the supply of power to the motor 2. The overcurrent limiting circuit 48 uses this shunt resistor 44 and comparator.
46 and a resistance circuit for setting the reference VR.

On the other hand, in the switching control unit 14, the above-mentioned comparator 26
Further, a predetermined reference signal V ₁ (see FIG. 2 (a)) for comparing / determining the content of the operation signal Oa is further added from the reference signal setting unit 50 to the input terminal of the. The output signal S ₂ of the comparator 26 is applied to the base of the switching transistor 52 in the next stage and also applied to the dynamic braking interruption control unit 18.

Of these, a relay 54 is connected between the collector of the transistor 52 and the V _B power supply. The relay 54 controls the on / off of the electromagnetic brake 16 mounted on the shaft of the motor 2 to mechanically brake the shaft. That is, here, when the relay 54 is turned on, the electromagnetic brake
16 is off (non-braking state), and when the relay 54 is off, the electromagnetic brake 16 is set to on (braking state). Here, the operation delay time peculiar to this electromagnetic brake 16 is set to t ₁ .

In the dynamic braking interruption control unit 18, the output signal S ₂ of the comparator 26 described above is applied to the delay circuit 58 (the delay time t ₂ here is t ₂ = t ₁ + Δα) via the inverter 56. Has been done. This delay circuit 58 has a time t ₁ from when the signal S ₂ rises to when the electromagnetic brake 16 actually operates.
More slightly time longer t _2, the output of inverter 56 (second
Figure (e)) is delayed, and its output signal
SD (see FIG. 2 (f)) is added to the inverting input terminal of the comparator 60 at the next stage.

The reference value RD from the reference signal setting unit 62 is added to the non-inverting input terminal of the comparator 60. Therefore, the comparator 60 lowers its output to a logic low level (L level) when the signal SD becomes larger than the reference value RD, and otherwise outputs its output to a logic high level (H level).
Level), that is, in a high impedance state. The output of the comparator 60 (see FIG. 2 (g)) is configured to be applied to the base of the switching transistor 36 in the dynamic braking circuit unit 12.

On the other hand, the speed detecting means 20 includes a pulse generator 64 which is mounted on the drive shaft of the motor 2 and outputs a pulse signal PS having a frequency corresponding to the speed of the motor 2, and the pulse signal PS which is a voltage signal corresponding to the frequency. It is composed of a frequency / voltage converter 66 for converting to SV. And this speed detecting means
The voltage signal SV that is the output of 20 is applied to the regenerative braking control unit 22 and is also fed back as a vehicle speed signal to a vehicle speed control unit (not shown) that controls the vehicle speed of the electric vehicle.

In addition, the regenerative braking control unit 22 monitors the operation signal Oa described above, and when braking, a predetermined delay time t ₃ (t ₃ = t ₂ + Δ
a delay control circuit 67 for opening the gate and outputting the voltage signal SV after α ′) has elapsed, and a switching transistor 68,
It is configured as the main part. For this reason, the transistor 68 is turned on when the motor 2 is still rotating even after the lapse of t ₃ seconds from the start of the braking, and is turned off otherwise.

Further, the collector of the transistor 68 is connected to the output terminal of the delay circuit 58 in the dynamic braking interruption control unit 18. When the transistor 68 is turned on, the delay circuit 58
The output signal SD of is forced to fall to almost zero level.

Next, the overall operation will be described.

First, when the accelerator is at a position other than the stop position, the duty of the signal S ₁ in the comparison and determination unit 10 in one cycle of the sawtooth wave WS changes according to the value of the operation signal Oa as described above, and accordingly. The conduction time of the transistor 40 of the motor drive unit 6 and the transistor 42 of the dynamic braking circuit unit 12 in the one cycle fluctuates as described above, and the speed of the motor 2 is set. In this case, as described above, the dynamic braking interruption control unit
Since the output of the comparator 60 of 18 has a high impedance, the operation of the transistor 42 is not affected.

Here, if the accelerator is moved to the stop position (see FIG. 70 in FIG. 3), the operation signal Oa becomes gradually smaller and the signal S ₁
Duty becomes zero, the transistor 42 of the dynamic braking circuit section 12 is turned on, and dynamic braking is applied (third embodiment).
(See Figure 72). At the same time, in the switching control unit 14, when the operation signal Oa becomes smaller than the reference signal V ₁ , the signal S ₂ becomes the logic L level, whereby the transistor 52 is turned off, that is, the relay 54 is turned off ( Fig. 2 (d)),
The electromagnetic brake 16 starts to operate. This electromagnetic brake 16 has a predetermined operation delay time after the transistor 52 is turned off.
It works effectively after t ₁ (see FIG. 74).

Further, as the signal S ₂ falls, the output of the inverter 56 rises (see FIG. 2 (e)), its rising edge is delayed by the delay circuit 58, and its output signal SD becomes larger than the reference signal RD. At t ₂ seconds later (see FIG. 2 (f)), the output of the comparator 60 falls to the logic level L (see FIG. 2 (g)). As a result, the transistors 36 and 42 in the dynamic braking circuit unit 12 are turned off.

Therefore, when the electromagnetic brake 16, which is the mechanical braking means, comes into operation, the dynamic braking of the traveling motor 2 is released (see FIG. 76 in FIG. 3), whereby the collector of the driving transistor 36 for dynamic braking is applied. Power consumption by the resistor R (see FIG. 1) connected to is stopped.

As described above, when the electric vehicle is stopped in the normal case, first, the motor 2 is dynamically braked until the electromagnetic brake 16, which is the mechanical braking means, operates, and the electromagnetic brake 16 is stopped.
After the start of the operation, the dynamic braking is stopped to prevent the battery 7 from being consumed.

As in the case described above, when the electromagnetic brake 16 operates normally and exerts the braking function, the rotation of the motor 2 is set to zero within t ₃ seconds after the braking start command is issued to the electromagnetic brake 16. Is set in advance, the regenerative braking control unit 22
Does not operate, and only the dynamic braking interruption control unit 18 effectively functions.

Next, a case where the electromagnetic brake 16 does not operate for some reason will be described.

In this case, the electromagnetic brake 16 does not operate even after t ₂ seconds have passed since the accelerator lever was operated to the stop position and a braking command was issued to the electromagnetic brake 16 (already generated power after t ₁ [= t ₂ −Δα] seconds). Braking has been interrupted), and generally the motor 2 is rotating. Therefore, as described above, slightly after t ₂ .
After t ₃ (t ₂ + Δα ′) seconds, the speed detection means 20 and the regenerative braking control unit 22 operate (see FIG. 78), and the output of the comparator 60 of the dynamic braking interruption control unit 18 is automatically forced. To the zero level (see FIG. 2 (g)). Then, the operation of the dynamic braking circuit section 12 which has been interrupted until then is restarted (see FIG. 80 in FIG. 3), the dynamic braking is applied to the motor 2 again, and the motor 2 is immediately stopped. Further, when the above-mentioned situation occurs on a slope, the running resistance due to the dynamic braking can be increased to avoid the worst case of the runaway.

Further, even when the electric vehicle stops normally, especially on a slope, but the electromagnetic brake 16 does not work for some reason, the motor 2 immediately passes after t ₃ seconds. Rotation is detected. Then, since the accelerator lever is at the stop position, the power generation braking means immediately acts again to avoid the runaway as in the case described above. Further, in the dynamic braking, the higher the motor rotation is, the larger the braking torque is, so that the vehicle speed does not easily become high on a slope or the like, and the braking function against runaway or the like is sufficiently exerted. In addition, the above Δ
By adjusting the time of α ', it is possible to give an appropriate sensitivity.

In the above embodiment, the time period during which the regenerative braking control unit 22 is effectively operated is set to be t ₃ (> t ₂ > t ₁ ) seconds after the start of the predetermined braking, but the present invention is not limited to this. However, the delay control circuit 67 in FIG. 1 may be omitted. As a result, during braking, as long as the motor 2 is rotating, the dynamic braking circuit section
12 is actuated, braking is performed together with the electromagnetic brake 16 that operates late, and the operation of the dynamic braking interruption control unit 18 is allowed only when the motor 2 is stopped, and the dynamic braking circuit unit 12 is used for power saving. The operation of can be interrupted (only the electromagnetic brake 16 operates for the first time at this stage). By doing so, although the power consumption of the battery 7 is slightly higher than that in the above-mentioned embodiment, the power generation braking is not performed until the motor is stopped from the beginning irrespective of the failure of the electromagnetic brake 16 and the motor is stopped. Since the means is activated, the reliability for preventing runaway on a slope or the like is further improved. In this case, the operation when the electromagnetic brake 16 is no longer effective after being temporarily stopped on a slope is similar to that of the above-described embodiment.

Further, in the above-described embodiment, the electromagnetic brake having the acting portion that mechanically acts on the motor shaft or the like by the relay control is used as the mechanical braking means, but this is not limited as long as it has an equivalent function. May be.

[Effect of device]

Since the present invention is configured and functions as described above, according to this, even when an abnormality occurs in the electromagnetic brake, it is possible to immediately activate the dynamic braking circuit section to perform dynamic braking, thereby ensuring the drive motor. Thus, it is possible to provide a braking control device for a non-conventional electric vehicle, in which the braking control or the stop control can be performed and therefore the reliability of the braking function can be greatly improved.

[Brief description of drawings]

FIG. 1 is a partially block diagram of a circuit configuration showing an embodiment of the present invention, and FIGS. 2A to 2G are diagrams for explaining the operation of the embodiment shown in FIG. Waveform diagram, third
The figure is a flow chart for explaining the operation of the embodiment shown in FIG. 2 ... Traveling motor, 4 ... Braking control device, 12 ... Dynamic braking circuit section for setting and controlling dynamic braking state, 14 ... Switching control section, 16 ... Electromagnetic brake as mechanical braking means, 18
...... Power generation braking interruption control unit, 20 ...... Speed detection means, 22 ......
Regeneration braking control unit.

Claims (1)

[Scope of utility model registration request] 1. A dynamic braking circuit section 12 which is energized by a predetermined stop signal to set a traveling motor 2 in a dynamic braking state, and a traveling motor 2 which is operated after receiving the stop signal and is preliminarily mounted on the traveling motor 2. The switching control unit 14 for starting and controlling the electromagnetic brake 16, and the switching control unit 14 is activated after a predetermined time t _{2 has} elapsed since the start control of the electromagnetic brake 16 by the switching control unit 14, and the running of the dynamic braking circuit unit 12 is performed. A braking control operation for releasing the braking control operation for the driving motor 2; and a speed detecting means 20 for detecting the rotation speed of the driving motor 2 in the running motor 2 and the dynamic braking. It operates when a speed signal of the traveling motor 2 is detected by the speed detecting means 20 after a predetermined time Δα 'has elapsed after the braking control operation of the traveling motor 2 of the circuit unit 12 is released, Power generation A regenerative braking control unit 22 that eliminates the release operation of the braking interruption control unit 18 and resets the dynamic braking circuit unit 12 to an operating state is installed side by side with the dynamic braking interruption control unit 18. Car braking control device.