JPH0847104A - Speed controller for electric motor vehicle - Google Patents

Abstract

PURPOSE:To provide a speed controller for an electric motor vehicle which can control to a speed corresponding to a traveling resistance and travel along the natural flow of a traffic when a road gradient or the resistance such as strong wind is varied in a constant speed control state and economically increase the available time of a battery. CONSTITUTION:When a normal-irregular auto cruise switch 14 is set to an 'irregular auto cruise mode', a controller 2 detects a torque change at the constant speed traveling of a selectively set speed V. When the torque change exceeds a preset torque change DELTAT or more, the torque change DELTAT is added in the direction in which an output torque is varied, and set. When it is set to the side in which the output torque is increased, the speed V is set lower by preset speed change DELTAV, while when the output torque is set to the lowering side, the speed V is set higher than the preset speed change DELTAV. This control is repeated to hold the substantially constant output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed control device for an electric vehicle, which controls the output torque of a running motor to control the speed during constant speed running.

[0002]

2. Description of the Related Art In recent years, when a driver sets a desired speed, the speed is stored, and the vehicle can be automatically driven at a constant speed without operating an accelerator pedal or the like. The number of vehicles equipped with an auto cruise device is increasing.

For example, in a gasoline engine vehicle, the above-mentioned constant speed traveling device is based on a vehicle speed signal from a vehicle speed sensor or the like.
There is a system in which the throttle valve opening is controlled to maintain a set vehicle speed (the vehicle speed desired and set by the driving vehicle) so that the vehicle can run at a constant speed. In such running control of a gasoline engine vehicle, it is difficult to accurately control the output torque determined by the fuel injection amount, the in-cylinder intake air flow rate, and the like.

On the other hand, in an electric vehicle, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Laid-Open Patent Publication No. 7-142104, there is one in which the output torque of a traveling motor is changed so as to keep a set vehicle speed constant, so that constant speed traveling can be performed.

[0005]

However, in general, a constant-speed traveling device for an automobile such as a highway is effective when the road is vacant, but cannot be used when the road is crowded. There is such a problem.

This is because a vehicle not equipped with a constant speed traveling device becomes slower or faster due to the influence of a slight increase or decrease in running resistance such as a slight slope of the road or wind. That is, a vehicle that is equipped with a constant-speed traveling device and is performing constant-speed traveling attempts to perform constant-speed traveling by performing speed control, but a vehicle that is not equipped with a constant-speed traveling device is equipped with a constant accelerator (output Because the vehicle is traveling at a speed close to (constant), when the traveling resistance fluctuates, a relative speed difference occurs between the vehicle equipped with the constant speed traveling device and the vehicle not equipped with the constant speed traveling device.

Also, in an electric vehicle, the load (running resistance)
If the vehicle travels at a constant speed even when fluctuates, there is a problem that the output fluctuates a lot and the battery does not last long.

The present invention has been made in view of the above circumstances, and when the running resistance fluctuates due to a road gradient, a strong wind or the like even in a constant speed control state, the speed is controlled according to the running resistance. It is an object of the present invention to provide a speed control device for an electric vehicle that enables traveling in accordance with the flow of natural traffic and that makes a battery and the like economical and long-lasting.

[0009]

In order to achieve the above object, a speed control device for an electric vehicle according to the present invention as set forth in claim 1 is an output of a motor for running at a constant speed running at a selectively set speed. Output torque detecting means for detecting a torque fluctuation, and a preset torque in a direction in which the output torque fluctuates when the fluctuation of the output torque exceeds a preset torque fluctuation amount. A torque setting means for adding and setting a change amount, and when the output torque is increased by the torque setting means, a preset speed change amount is reduced from the set speed and is set. When the output torque is set to the lower side, the set speed varying means is provided to increase and set a preset speed change amount from the set speed.

In order to achieve the above object, a speed control device for an electric vehicle according to a second aspect of the present invention controls the output torque of a traveling motor to perform constant traveling at a selectively set speed. The fluctuation of the output torque of the traveling motor when traveling at a constant speed at the traveling control means and the selectively set speed is detected, and the variation of the output torque exceeds the preset torque fluctuation amount. In this case, the preset amount of torque change is added in the direction in which the output torque fluctuates, and when the output torque is set to increase, the preset speed is changed from the preset speed. A variable constant speed traveling control means for increasing and setting a preset speed change amount from the set speed when the output torque is set to the lower side while setting the change amount by decreasing It is intended.

Further, a speed control device for an electric vehicle according to a third aspect of the present invention is the speed control device for an electric vehicle according to the second aspect, wherein the preset torque of the irregular constant speed traveling control means is set. At least one of the fluctuation amount, the preset torque change amount, the preset speed change amount set to decrease and the preset speed change amount set to increase, is set to the operating state. It is variably set accordingly.

[0012]

In the speed control device for the electric vehicle according to the first aspect of the present invention, first, the output torque detecting means detects the fluctuation of the output torque of the traveling motor when the vehicle is traveling at a constant speed at the selectively set speed. Then, in the torque setting means, when the fluctuation of the output torque is equal to or more than the preset torque fluctuation amount, the preset torque change amount is added in the direction in which the output torque fluctuates. Set. As a result, when the set speed varying means sets the output torque in the torque setting means to increase, the preset speed change amount is reduced from the set speed and the output torque is set. When the speed is set to the descending side, the speed change amount set in advance is increased from the set speed and set.

In the speed control device for an electric vehicle according to a second aspect of the present invention, the constant speed running control means controls the output torque of the running motor to carry out the constant speed running at the selectively set speed. Further, the irregular constant-speed traveling control means detects a variation in the output torque of the traveling motor when the vehicle is traveling at a constant speed at the selectively set speed, and the variation in the output torque is a preset torque variation. When the output torque is greater than or equal to the amount, the torque change amount set in advance is set in the direction in which the output torque fluctuates, and when the output torque is set to increase, the set speed While the preset speed change amount is reduced and set, on the other hand, when the output torque is set to the lower side, the preset speed change amount is increased and set from the set speed.

Further, according to a third aspect of the present invention, there is provided a speed control device for an electric vehicle according to the second aspect, wherein the preset constant torque variation amount of the irregular constant speed traveling control means and the preset torque variation are set. At least one of the amount, the preset speed change amount that is set to be decreased and the preset speed change amount that is increased to be set is variably set according to an operating state.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show an embodiment of the present invention, FIG. 1 is a circuit block diagram of a motor control system, FIG. 2 is a flow chart of irregular auto cruise control, and FIG. 3 is an example of control in a running performance diagram of a vehicle. FIG. 4 is a schematic explanatory diagram showing FIG. 3 at the position of the vehicle.

In FIG. 1, reference numeral 1 is a running motor mounted on an electric vehicle, and in the present embodiment, an AC induction motor. A transaxle (not shown) is connected to the motor 1, and the driving force from the transaxle is transmitted to both front wheels (neither is shown) via the left and right front wheel shafts, for example. There is.

Further, the motor 1 is connected to a controller 2, and is connected via an inverter 3 of the controller 2 to a main battery 4 which is a main power source for traveling drive.

The controller 2 includes a CPU 5 and a ROM
6, a RAM 7, and an I / O interface 8 have a microcomputer 9 connected via a bus.
The drive circuit 10 is connected to the output port of the O interface 8.
The inverter 3 is connected via.

The torque control of the motor 1 is replaced with a current command corresponding to the number of revolutions in the drive circuit 10 with respect to the target torque calculated by the CPU 5 of the microcomputer 9, and the inverter 3 is commanded. Then, the direct-current voltage from the main battery 4 is converted into a high frequency wave of a predetermined voltage by the inverter 3 so as to be performed.

A current sensor 11 for detecting the drive current of the motor 1 is provided on the connection line between the motor 1 and the inverter 3, and the current sensor 11 is connected to the microcomputer 9. It is connected via the I / O interface 8.

Furthermore, sensor switches such as a rotation speed sensor 12 for detecting the rotation speed of the motor rotor of the motor 1, a vehicle speed sensor 13, a normal / irregular auto cruise switch 14, an accelerator pedal switch 15, a brake pedal switch 16 are provided. The microcomputer 9 is provided with the I
It is connected via the / O interface 8.

The above-mentioned normal / irregular auto cruise switch 1
4 is a "normal auto cruise mode" (constant speed running control mode; a mode that keeps the speed constant even if running resistance fluctuates), an "irregular auto cruise mode" (mode of substantially constant output control; depending on running resistance) Speed control mode),
It is a switch for switching to three modes of "OFF mode" (normal manual traveling mode).

The accelerator pedal switch 15 is also used.
Is a switch that is connected to an accelerator pedal provided on the floor of the driver's seat of an electric vehicle and that is turned on at a minute stroke when the accelerator pedal is depressed.

Similarly, the brake pedal switch 16 is turned on at the minute stroke when the brake pedal is depressed.
It is a switch to do.

It should be noted that the accelerator pedal switch 15 and the brake pedal switch 16 are auto cruise canceling switches which, when turned on, put the normal / irregular auto cruise switch 14 in the "OFF mode". As the auto-cruise canceling switch, although not particularly shown, a shift switch or the like, which is connected to the base of the shift lever and detects the shift position, is connected to the microcomputer 9 through the I / O interface 8.

Next, when the normal / irregular auto cruise switch 14 is set to the "irregular auto cruise mode",
Speed control performed by the controller 2 will be described with reference to the flowchart of FIG.

When the program starts, first, in step S1, the vehicle speed V is measured by the signal from the vehicle speed sensor 13, and the process proceeds to step S2 where a fixed vehicle speed Vc for constant speed traveling is obtained.
Is commanded as the vehicle speed V (V = Vc; V is the set speed)
After that, the process proceeds to step S3, and the torque of the motor 1 at that time is stored in the RAM 7 as the initial torque T0 (T = T0; T is a set torque). The torque of the motor 1 is previously stored in the ROM based on the value from the current sensor 11.
It is obtained from a current-torque characteristic map or calculation formula stored in the memory 6. Further, the torque instruction value commanded by the microcomputer 9 to the drive circuit 10 may be used as it is.

Next, at step S4, it is judged whether or not the auto cruise is canceled by the normal / irregular auto cruise switch 14, the accelerator pedal switch 15, the brake pedal switch 16, and other shift switches. If the auto cruise has not been cancelled, the process proceeds to step S5. If the auto cruise has been cancelled, the process proceeds to step S6 and normal manual cruise control, that is, the "irregular auto cruise mode" is canceled and the "OFF mode". Becomes

At step S4, if it is determined that the auto cruise has not been canceled and the process proceeds to step S5,
The torque value Ti at that time is read, and the routine proceeds to step S7.

In step S7, torque fluctuations (load,
Fluctuation of running resistance) is large, that is, Ti-T ≧
ΔT or Ti −T ≦ −ΔT (| Ti −T | ≧ ΔT)
Is determined. Where ΔT
Is a torque change amount set in the ROM 6 in advance by experiments or the like, and is set to, for example, ΔT = 0.5 kgf · m (corresponding driving force ΔF = 12.5 kgf).

In step S7, the torque fluctuation is small, and Ti-T <ΔT or Ti-T> -ΔT (|
If Ti-T | <ΔT), the process returns to step S4 again, the torque fluctuation is large, and Ti-T ≧ ΔT or Ti
If −T ≦ −ΔT (| Ti −T | ≧ ΔT), the process proceeds to step S8, and a fixed command is issued to change the torque of the motor 1. That is, in step S7, Ti-T ≧ Δ
In the case of T, T = T + ΔT, and in the case of Ti −T ≦ −ΔT, T = T−ΔT.

Next, in step S9, similarly to step S4, it is determined again whether or not the auto cruise has been cancelled. If the auto cruise has not been cancelled, the process proceeds to step S10. If the auto-cruise has been canceled, the routine proceeds to step S6, where the normal manual cruise control, that is, the "irregular auto-cruise mode" is canceled and the "OFF mode" is entered.

In step S9, if it is determined that the auto-cruise has not been cancelled, and if the process proceeds to step S10, the torque fixing command is canceled, and the process proceeds to step S11, where a command to change the fixed vehicle speed is issued.

That is, Ti-T≥Δ in step S7.
If it is determined to be T, and T = T + ΔT in step S8, V = V-ΔV and a fixed vehicle speed change command are issued, it is determined in step S7 that Ti −T ≦ −ΔT, and in step S8, When T = T-ΔT, V = V + ΔV and a fixed vehicle speed change command are issued. Here, ΔV is a speed change amount set in the ROM 6 in advance by experiments or the like, and is set to, for example, ΔV = 5 km / h (corresponding to this, the rotational speed of the motor 1 ΔN = 333 rpm).

Then, after executing the above step S11,
Returning to step S4 again, the control is repeated.

Next, an example of control in the "irregular auto cruise mode" will be described with reference to FIGS. In the running performance diagram of FIG. 3, the curve shown by the solid line descending to the right is the maximum driving force curve of the electric vehicle of this embodiment, and the curve shown by the broken line descending to the right is a certain constant value of the electric vehicle of this embodiment. The driving force (output) curve and the curve shown by the solid line rising to the right show the running resistance curve for each road gradient.

Driving force P (kW), torque Tq (kgf · m),
In this embodiment, the relationship between the motor rotation speed N (rpm) is
For example, given by the equation P = Tq.N / 974, it is assumed that the maximum driving force curve is a 60 kW curve and the constant driving force curve is a 30 kW curve. In addition, there is no running resistance other than the road gradient.

As shown in FIG. 4, first, the vehicle traveling at the speed V0 at the position x1 of 0% gradient (flat) is shown in FIG.
It is indicated by point P0 in the running performance diagram of.

In this state, when the driver sets the normal / irregular auto-cruise switch 14 to the "irregular auto-cruise mode" and the vehicle runs on a road having a 3% gradient, the vehicle tries to maintain the speed V0. The torque of the motor 1 is increased.

When the increase in torque exceeds ΔT, the torque of the motor 1 is fixedly commanded to a value increased by ΔT (point P1 in FIG. 3), and the speed is further decreased by ΔV, as shown at position x2. V1 is reached (point P10 in FIG. 3), the torque fixing command for the motor 1 is released, and the vehicle is controlled to travel at a constant speed V1.

At this time, as shown in FIG. 3, in order to travel at a constant speed at the speed V1, the torque of the motor 1 is further increased. When the increase of the torque becomes ΔT or more, the motor 1 is driven. The torque is fixedly commanded to a value increased by ΔT (point P2 in FIG. 3), and the speed is further reduced by ΔV to V2 as shown at position x3 (see P20 in FIG. 3).
Point), the torque fixing command for the motor 1 is released, and the vehicle is controlled to travel at a constant speed V2.

Then, as shown in FIG. 3, the torque of the motor 1 is further increased in order to travel at a constant speed at the speed V2, and when the increase of the torque becomes ΔT or more,
The torque of the motor 1 is fixedly commanded to have a value increased by ΔT (point P3 in FIG. 3), and the speed is further reduced by ΔV to V3 as shown at position x4 (point P30 in FIG. 3). The torque fixed command of is released, and the vehicle speed V3
Is controlled to run at a constant speed.

Similarly, as shown in FIG. 3, since the vehicle travels at a constant speed at the speed V3, the torque of the motor 1 is further increased, and when the torque increase is ΔT or more, the torque of the motor 1 is increased. Is fixed to a value increased by ΔT (P4 point in FIG. 3), and the speed is further decreased by ΔV to V4 as shown at position x5 (P40 point in FIG. 3), and the torque fixing command for the motor 1 is given. When the vehicle is released, the vehicle is controlled to travel at a constant speed V4.

Here, since the driving force is substantially appropriate for traveling on a road having a gradient of 3%, even if the control is performed so that the vehicle travels at a constant speed at the speed V4, there is no large fluctuation in the torque.

When the vehicle travels again on the road having a 0% gradient (flat) from this state, the vehicle tries to maintain the speed V4, and the torque of the motor 1 is reduced.

When the decrease of the torque becomes ΔT or more, the torque of the motor 1 is fixedly commanded to the value decreased by ΔT (point P5 in FIG. 3), and the speed is further increased by ΔV, as shown at the position x6. V3 is reached (point P30 in FIG. 3), the torque fixing command for the motor 1 is released, and the vehicle is controlled to travel at a constant speed at V3.

At this time, as shown in FIG. 3, the torque of the motor 1 is further reduced in order to carry out constant speed traveling at the speed V3. When this torque reduction becomes ΔT or more, the motor 1 is driven. The torque is fixedly commanded to a value decreased by ΔT (point P6 in FIG. 3), and the speed is further increased by ΔV to V2 as shown at position x7 (P20 in FIG. 3).
Point), the torque fixing command for the motor 1 is released, and the vehicle is controlled to travel at a constant speed V2.

Then, as shown in FIG. 3, in order to travel at a constant speed at the speed V2, the torque of the motor 1 is further reduced, and when this torque reduction becomes ΔT or more,
The torque of the motor 1 is fixedly commanded to a value decreased by ΔT (point P7 in FIG. 3), and the speed is further increased by ΔV to V1 as shown at position x8 (point P10 in FIG. 3). The torque fixed command of is released and the vehicle speed V1
Is controlled to run at a constant speed.

Similarly, as shown in FIG. 3, since the vehicle travels at a constant speed at the speed V1, the torque of the motor 1 is further reduced, and when the torque reduction becomes ΔT or more, the torque of the motor 1 is increased. Is fixed to a value reduced by ΔT (point P8 in FIG. 3), and the speed is further increased by ΔV to V0 as shown at position x9 (point P0 in FIG. 3). When the vehicle is released, the vehicle is controlled to run at a constant speed V0.

Here, since the driving force is substantially appropriate for traveling on a road having a 0% gradient, even if control is performed so that the vehicle travels at a constant speed at the speed V0, there is no large fluctuation in the torque.

As a result of such control, as shown in FIG. 3, when the electric vehicle runs, the running resistance for each road gradient is 0.
Even if the gradient changes from% gradient → 3% gradient → 0% gradient, the vehicle can travel with a substantially constant driving force (constant driving force indicated by a broken line) when the “irregular auto cruise mode” is set.

Therefore, for example, traveling at a speed close to a constant accelerator (constant output), which is slower or faster in front of the driving vehicle due to the influence of a slight slope of the road or increase / decrease in traveling resistance such as wind. Even if there is a vehicle running, in the "irregular auto-cruise mode", the speed changes in the same way, so there is no relative speed difference, and it is possible to drive according to the natural traffic flow. .

Since the vehicle can travel with a substantially constant driving force (output), the battery current given by ΔW = i ² · R (ΔW; motor output, i; battery current, R; resistance) is approximately It can be kept constant, overload can be prevented, economical traveling can be performed, and the cruising range of the vehicle and the battery life can be extended.

In this embodiment, in the flowchart of FIG. 2, the reference value of the torque fluctuation determined in step S7,
That is, the amount of torque fluctuation and the amount of torque change that is changed in step S8 are set in advance as ΔT, but the reference value of increasing torque fluctuation, the reference value of decreasing torque fluctuation, and the increasing torque change. The amount of change in torque and the amount of change in torque to be decreased may be set differently, and the reference value for increasing torque fluctuation and the reference value for decreasing torque change are set to the same value, and the increasing torque change amount and decreasing torque change amount are decreased. The amount of torque change to be caused may be set differently.

Further, a reference value of increasing torque fluctuation,
The reference value of the descending torque fluctuation, the torque change amount to be increased, and the torque change amount to be decreased are not fixed values, but are set in advance in a map or the like so that they can be changed according to driving conditions such as vehicle speed. You can keep it.

Further, in the present embodiment, ΔT is set to, for example, 0.5 kgf · m, but a value smaller than this value (for example, 0.1 kgf · m) is set, and finer and smoother control is performed. May be enabled, while 0.5
Greater than kgf ・ m (eg 1.0 kgf ・ m etc.)
May be set to improve the convergence. In addition, if the value of ΔT is changed according to the operating state in this way (for example,
ΔT is set to a large value in the transient operation state, and ΔT is set to a small value when relatively stable running continues),
It can be used more effectively.

Further, in the present embodiment, in the flowchart of FIG. 2, the speed change amount ΔV in step S11 is the same value when the speed is increased and when it is decreased, but different values are set. Further, it may be set in advance in a map or the like so that it can be changed according to driving conditions such as vehicle speed.

Further, in the present embodiment, ΔV is set to, for example, 5 km / h, but it is not limited to this value.

Further, in the present embodiment, the vehicle speed is obtained from the vehicle speed sensor, but it may be calculated from the motor rotation speed and the gear ratio.

In this embodiment, an example in which the traveling motor is an AC induction motor has been described, but the present invention is not limited to this, and the motor may be an AC synchronous motor or a DC motor. Is also good.

[0061]

As described above, according to the first aspect of the invention, even when the running resistance changes due to a road gradient, a strong wind or the like even in the constant speed control state, the speed corresponding to the running resistance. It is possible to allow the vehicle to travel in accordance with the natural flow of traffic and to make the battery and the like economical and long-lasting.

According to the second aspect of the present invention, the driver performs a constant speed traveling by the constant speed traveling control means while the vehicle is traveling and the road is vacant, or when the road is crowded, or When it is desired to travel economically, the irregular constant speed traveling control means can select traveling along the flow of traffic or efficient traveling, and the constant speed traveling control device can be effectively used.

Further, according to the invention described in claim 3, when the driver performs the constant speed traveling by the irregular constant speed traveling control means, in addition to the effect of the invention according to the second aspect, the torque fluctuation set in advance is set. Amount, preset torque change amount,
At least one of the preset speed change amount that is set to decrease and the preset speed change amount that is set to increase is set variably according to the operating state, so fine control according to the operating state is performed. As a result, it is possible to travel more naturally along the flow of traffic, and to travel more efficiently.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of a motor control system according to an embodiment of the present invention.

FIG. 2 is a flowchart of irregular auto cruise control according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an example of control according to an embodiment of the present invention in a running performance diagram of a vehicle.

FIG. 4 is a schematic explanatory view showing the position of the vehicle in FIG.

[Explanation of symbols]

 1 Traveling Motor 2 Controller 14 Normal / Anomalous Auto Cruise Switch T Set Torque Ti Output Torque V Set Speed ΔT Preset Torque Fluctuation Amount (Torque Change Amount) ΔV Preset Speed Change Amount

Claims (3)

[Claims] 1. An output torque detecting means for detecting a variation in output torque of a traveling motor when the vehicle is traveling at a constant speed at a selectively set speed, and a variation in the output torque which is set in advance. When the output torque is greater than or equal to the amount, the torque setting means for setting the torque change amount set in advance in the direction in which the output torque fluctuates, and the torque setting means for setting the output torque increasing side When it is set, the preset speed change amount is decreased from the set speed, and when the output torque is set to decrease, the preset speed change amount is increased from the set speed. A speed control device for an electric vehicle, comprising: 2. A constant speed traveling control means for controlling the output torque of the traveling motor to carry out constant traveling at a selectively set speed, and a traveling motor for carrying out constant speed traveling at the selectively set speed. If the output torque fluctuation is detected, and this output torque fluctuation exceeds the preset torque fluctuation amount,
When the output torque is set in the direction in which the output torque fluctuates, a preset torque change amount is added, and when the output torque is set to increase, a preset speed change amount from the set speed is set. On the other hand, when the output torque is set to the descending side, an irregular constant speed traveling control means for increasing and setting a preset speed change amount from the set speed is provided. A characteristic speed control device for electric vehicles. 3. The preset torque fluctuation amount of the irregular constant speed traveling control means, the preset torque change amount, and the preset speed change amount to be reduced and set. 3. The speed control device for an electric vehicle according to claim 2, wherein at least one of the preset speed change amounts that are increased and set is variably set according to a driving state.