JP3063787B2 - Electric vehicle control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle control device, and more particularly to an electric vehicle control device suitable for controlling a DC shunt motor used as a drive motor (electric motor) in an electric vehicle.

[0002]

2. Description of the Related Art Generally, when an electric vehicle is driven by using a DC shunt motor as a main motor, it is necessary to have the same characteristics as a DC series motor and to generate a large torque during power running acceleration. Or field current)
Has been widely performed (control by pulse width modulation). In this case, the armature current (armature current) must be controlled so as to always take a value proportional to the field current (field current).

By the way, the rotation speed N of the DC shunt motor is
Is determined by the field current I _f, as shown in FIG. 5, the torque T of the DC shunt-wound motor is determined by the armature current I _a as shown in FIG. From these relationships, the rotational speed N
There is a relationship between the torque and the torque T as shown by a solid line in FIG. 7, and when the vehicle runs at a constant speed V (40 km / h), the motor speed N ₁ , that is, the speed V (40 km / h) Duty control (accelerator work), which will be described later, is performed so that the point P ₁ (torque value T ₁ ) matches the running balance point P (torque value T ₂ ) at the rotation speed N ₁ , thereby reducing the driving force (torque). Matching. A dotted line R in FIG. 7 shows a running resistance curve.

Here, the duty control of the armature current for determining the motor torque will be described with reference to FIGS. 8, an accelerator signal is input to a non-inverting input terminal of a comparator 11, and a reference triangular wave (or sawtooth wave) from a reference wave generating circuit (not shown) is input to an inverting input terminal. The comparator 11
Is connected to the base of a power transistor 12 for drive control of a DC shunt motor. The collector of the power transistor 12 is connected to the positive electrode of the main battery via an armature coil 13 and the emitter is connected to the main battery. It is connected to the negative electrode. Meanwhile, the relationship between the accelerator signal and the accelerator opening, is proportional, as shown in FIG. 9, becomes V _x (V) is an accelerator signal at full throttle, the accelerator signal becomes 0 (V) to the accelerator is fully closed It has become.
For example, when the accelerator half open, and the accelerator signal V _h and the triangular wave shown in FIG. 10 a is compared in the comparator 11,
As a result, the power transistor 12 is controlled at a 1/2 duty as shown by b in FIG. 10, and as a result, the energized voltage of the armature coil 13 is reduced to 1/2.

[0005] Figure 4 in solid lines, the energization voltage armature current in the case of Zentsu I _a correlation control characteristics of the field current I _f I of the armature coils 13 (x), the chain line is energized voltage predetermined point armature current I _a and the field current I _f in the case of control with a duty ratio
Respectively show the correlation control characteristics I (x). As can be seen by comparing FIG. 4 with FIG. 5 described above, the running speed V is controlled by duty control of the energizing voltage of the armature coil 13, that is, by the accelerator work for adjusting the accelerator opening to a predetermined opening. The matching of the driving force at (motor rotation speed N ₁ ) has been performed.

[0006]

As described above, the speed V
When the vehicle travels at a constant speed (for example, 40 km / h), the duty control of the armature coil energizing voltage is performed, so that a chopper loss (controller loss) is involved. In the case of an electric vehicle, the distance traveled per charge was shortened.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems of the prior art, and an object of the present invention is to provide an electric vehicle control device capable of extending the traveling distance per charge.

[0008]

An electric vehicle control apparatus according to the present invention includes a control unit for duty-controlling an energizing voltage of an armature coil of a DC shunt motor in accordance with an accelerator signal, and the control unit includes the control unit. Economy / control mode
A mode changeover switch for switching to any of the power modes is provided. Then, when the mode changeover switch is set to the economy mode, the control unit sets a correlation control characteristic between the field current and the armature current of the DC shunt motor,
A mode switching function is provided for switching from the correlation control characteristics in the power mode to the correlation control characteristics in the economy mode in which the armature current value becomes a current value corresponding to the entire region of the armature coil. With such a configuration, the object described above is to be achieved.

[0009]

When the mode changeover switch is set to the economy mode, the correlation control characteristic between the field current and the armature current becomes the correlation control characteristic in the economy mode, and the full conduction control of the armature coil is performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows the configuration of an electric vehicle control apparatus according to one embodiment of the present invention. In this figure, a controller 1 as a control unit includes an accelerator circuit 2 that outputs an accelerator signal corresponding to an accelerator opening, a mode changeover switch 3 that switches the control mode of the controller 1 to one of economy / power modes, Is connected. Further, a DC shunt motor 4 is connected to the controller 1, and the armature current I flowing through the armature coil 5 and the field coil 6 constituting the DC shunt motor 4, respectively.
_a , the field current _If is controlled by the controller 1. The armature current _Ia is detected by armature current detection means 7 (which is constituted by a shunt resistor) and fed back to the controller 1. The armature current I _a is
As described in the section of the background art, the comparator forming the controller 1 compares the reference triangular wave with the accelerator signal, and configures the controller 1 according to the pulse width of the PWM signal output from the comparator. On / off of the power transistor for motor drive control is controlled, and the energized voltage of the armature coil 5 is changed by duty control in this manner.

Here, the economy mode and the power mode which are control modes of the controller 1 will be described. FIG. 2 shows the armature current I _a in both modes.
The graph shows the correlation control characteristic between the field current If and the field current _If . In the figure, the solid line indicates the correlation control characteristic I (x) in the power mode.
And the dashed line is the correlation control characteristic I ′ (x) in the economy mode. The power mode is the same control mode as the conventional electric vehicle, and the economy mode is the speed V (4
0 km / h) This is a control mode in which the vehicle travels at a constant speed and does not require much motor torque. These control modes are switched by the controller 1 in accordance with the setting of the mode switch 3.

Next, the overall operation and effect of this embodiment will be described. Now, when the mode switch 3 is operated and the economy mode is set while the vehicle is traveling at a constant speed V (40 km / h), the control mode of the controller 1 is changed from the power mode to the economy mode. The correlation control characteristic between the child current _Ia and the field current _If changes from I (x) to I '(x). Since the rotation speed N of the DC shunt-wound motor 4 is determined by the above-mentioned as field current I _f, the motor rotational speed at this time is to N _1, the field current at that time is I _f1 (see FIG. 5 ). The field current I
_f is controlled so as in a state that satisfies a correlation control characteristic I '(x) from satisfying state correlation control characteristics I (x) in FIG. 2, as a result, the armature current I _a in FIG. 2 I _a2
To I _a1 and the armature current I _a decreases. In other words, the field current in the motor rotational speed N ₁ in the velocity V I _f1
A balance point of the armature current I _a is shifted to the point A from the point B, the armature current I _a is made of I _a2 in I _a1. On the other hand,
Armature current I _a, so determined by the motor torque (see FIG. 6), the motor torque at speed V, as shown in FIG. 3 becomes torque T ₂ of the running balance point P from the torque T ₁ of the P ₁ point, This is the entire conduction region. For this reason, the duty control of the energization voltage of the armature coil 5 becomes unnecessary. In FIG. 3, the solid line indicates the correlation control characteristic I in the power mode.
(X) shows the motor torque-rotation speed characteristic corresponding to the correlation control characteristic I '(x) in the economy mode.
, And the curve indicated by the symbol R is a running resistance curve.

As described above, according to this embodiment,
When the vehicle travels at a constant speed V, setting the mode changeover switch 3 to the economy mode eliminates the need to perform duty control of the energizing voltage of the armature coil 5 of the DC shunt motor 4 and allows the accelerator to be fully opened. This makes it possible to drive the vehicle without changing the chopper loss, thereby increasing the mileage per charge.
Since both power modes can be easily switched and set by operating the mode changeover switch 3, the acceleration mode and the uphill mode are reduced by switching to the power mode at the time of acceleration or hill climbing requiring the motor torque. However, since the entire conduction region can be used at the speed V, chopper control of the power transistor for motor drive control is not performed, which is advantageous in heat dissipation measures.

[0015]

The present invention is constructed and functions as described above. According to this, by setting the mode changeover switch to the economy mode, the conduction voltage of the armature coil is controlled in full conduction. In this regard, it is possible to provide an unprecedented excellent electric vehicle control device in which the chopper loss of the control unit is reduced and the traveling distance per charge can be extended.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

2 is a graph showing the correlation control characteristic of the armature current I _a and the field current I _f in the economy mode and the power mode of the controller.

FIG. 3 is a diagram for explaining the operation of the embodiment of FIG. 1;

FIG. 4 is a diagram showing a correlation control characteristic between an armature current and a field current of a DC shunt motor in a conventional example.

FIG. 5 is a diagram showing a relationship between a field current and a rotation speed of the DC shunt motor.

FIG. 6 is a diagram showing a relationship between a torque of a DC shunt motor and an armature current.

FIG. 7 is a diagram showing a relationship between a motor torque and a rotation speed together with a running resistance curve.

8 to 10 are diagrams for explaining duty control of energized voltage of an armature coil.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Controller as control part 3 Mode switch 4 DC shunt motor 5 Armature coil

Claims (1)

(57) [Claims] 1. A control unit for duty-controlling an energized voltage of an armature coil of a DC shunt motor in accordance with an accelerator signal, wherein the control mode of the control unit is set to one of economy / power. Along with a mode changeover switch for switching to a mode, the control unit, when the mode changeover switch is set to economy mode, the correlation control characteristics between the field current and the armature current of the DC shunt motor, It has a mode switching function of switching from the correlation control characteristic in the power mode to the correlation control characteristic in the economy mode in which the armature current value becomes a current value corresponding to the entire communication region of the armature coil. Electric vehicle control device.