JPH08186902A - Controller of motor for vehicle - Google Patents

Abstract

PURPOSE: To obtain a controller of a motor for a vehicle in which accelerating and slope climbing performances are improved. CONSTITUTION: Two types of PWM signals are input to a motor circuit 12. The first duty factor Ad of the one signal is set by a first duty factor setter 20 based on an acceleration command from an accelerator 22, and the second duty factor Nd of the other signal is set by a second duty factor setter 30 based on information from a number-of-revolutions detector 32. A current limiter 52 detects a motor current by a current detector 54, alters the first, second duty factors by a switching element 40 when it exceeds a current limit value Im, and protects a motor 10. A comparator 42 compares the duty factor Ad with the duty factor Nd. In the case of Nd>=Ad or Nd<Ad, the signal having the first or second duty factor is output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle motor control device.

[0002]

2. Description of the Related Art Conventionally, electric vehicles have been used to move people with weak legs. This electric vehicle has already been widely sold and is well known, but as a document specifically disclosing this electric vehicle, there is Japanese Utility Model Publication No. 2-143931.

FIG. 6 is a block circuit diagram for driving and controlling a motor 100 of a conventional electric vehicle, and details of the motor circuit 101 are omitted in FIG. This controller is
Pulse width modulation output to the motor circuit 101 (hereinafter, P
The signal of the motor 1 is changed by changing the duty of the signal.
The rotation speed and the rotation torque of 00 are controlled. For this purpose, a duty setting unit 104 to which the acceleration command information from the Alcel 102 is input is provided. As shown in FIG. 7A, the duty setting unit 104 sets the duty larger as the accelerator opening increases. For example, if the accelerator opening is 100%, the duty is set to 100%. There is. FIG. 7B shows P
An example of the WM signal is shown, where duty = (b / a)
× 100, and the duty setting unit 104 is shown in FIG.
The duty is set by changing the pulse width b.

This control device is provided with a current limiting section 106 and a current detecting section 108. Current detector 108
Is for detecting a current supplied to the motor 100. The current limiting unit 106 compares the detected current with a preset current limiting value Im, and when the detected current exceeds the current limiting value Im, the duty setting unit 104.
Change the output duty to be smaller,
For example, the duty is set to 0% to protect the motor 100 from being damaged by an excessive current.

[0005]

FIG. 8 and FIG. 9 are similar to FIG.
FIG. 7 is a characteristic diagram showing control characteristics of the conventional vehicle-dedicated device for a vehicle shown in FIG. FIG. 8 shows the duty setting unit 104.
When the PWM signal obtained in step 3 is directly supplied to the motor circuit 101 without current limitation, the motor 1
The relationship between the rotational torque T of 00 and the rotational speed N is shown.
The solid line in FIG. 8 is the duty (that is, the accelerator is fully open) 10
The characteristic is shown in the case of 0%, and the rotational speed N and the torque T are in inverse proportion to each other, and the linear characteristic has a constant inclination. When the duty is smaller than this, as shown by the broken line and the alternate long and short dash line in the figure, the rotation speed N-torque T characteristic shifts obliquely downward while maintaining a constant inclination.

On the other hand, FIG. 9 shows a characteristic showing the relationship between the rotational speed N and the rotational torque T when the current limiting unit 106 current limits the PWM signal output from the duty setting unit 104. In this case, when the current value detected by the current detector 108 exceeds the current limit value Im, the driving state is such that the rotational torque T is significantly reduced.

Therefore, even if the accelerator opening is set to a large value during acceleration or climbing, the rotational torque by the motor 100 is greatly reduced, so that the acceleration time or climbing performance is greatly limited.

Therefore, an object of the present invention is to ignore the acceleration command and to obtain a good rotational torque characteristic when the accelerator opening is increased on the basis of the acceleration command and the current is limited. It is an object of the present invention to provide a control device for a motor for a vehicle, which can drive and control the motor so as to be obtained.

[0009]

According to a first aspect of the present invention, there is provided a vehicle motor control device for driving and controlling a vehicle motor based on a signal input to the motor circuit. First signal setting means for setting and outputting a first signal based on acceleration command information, and rotation speed detecting means for detecting the rotation speed of the motor,
Second signal setting means for setting and outputting a second signal input to the motor circuit based on the rotation speed information of the motor, and selectively switching the first or second signal. The switching means for outputting and the current flowing through the motor are detected, and when the detected current exceeds a preset current limit value, the signal from the switching means is changed and output to the motor circuit, and the current flowing through the motor. And a current limiting unit for limiting the current, and when the current limiting unit receives the current limitation by outputting the first signal to the motor circuit,
Switching control means for controlling the switching to the second signal by the switching means is provided.

According to the first aspect of the invention, the motor is not controlled only based on the first signal set based on the acceleration command information, but in addition to this, the motor is set based on the rotation information of the motor. A second signal is being generated. If the motor is driven and controlled only based on the first signal, for example,
When the accelerator is suddenly fully opened in the medium speed rotation range, the current limiting means significantly limits the current value supplied to the motor, resulting in a reduction in the rotation torque. As described above, when the current limiting unit receives the current limitation by outputting the first signal to the motor circuit, the switching unit outputs the second signal to the motor circuit instead of the first signal. The case of being subject to the current limitation is a case where the information for setting the accelerator opening excessively large with respect to the actual motor rotation speed is input, and in this case, the motor is driven by the second signal based on the rotation information. By driving, the vehicle can be driven with an optimum torque without being subject to current limitation.

According to a second aspect of the present invention, each of the first and second signals of the first aspect of the invention is a pulse width modulated signal having a first duty and a pulse width modulated signal having a second duty. It is what Also in this case, similarly, when the current limitation is caused by outputting the pulse width modulation signal of the first duty to the motor circuit, the switching means replaces the pulse width modulation signal of the first duty with the pulse width modulation signal. The pulse width modulation signal of the second duty is output. As a result, similarly to the first aspect of the invention, even when an acceleration command for an accelerator opening that is excessively high with respect to the actual motor speed is input, the motor can be driven with the optimum torque.

As the switching means in the invention of claim 2, as shown in claim 3, the pulse width modulation signal having the smaller duty of the first duty and the second duty is preferentially output. be able to. In this case, even when the current is limited by the pulse width modulation signal having the first duty, the motor can be drive-controlled by the pulse width modulation signal having the second duty, which has a smaller duty. Optimal motor control can be performed without any restrictions.

The second duty is defined as in claim 4.
It is preferable that the duty is set such that a current equal to or less than the current limit value and a current near the current limit value is always supplied to the motor in association with the rotation speed of the motor. With this configuration, the drive control can be performed with the maximum torque obtained when the motor is supplied with a current at or near the current limit value.

According to a fifth aspect of the invention, similarly to the second aspect of the invention, the pulse width modulation signal having the first and second duty is switched and output to the motor. At this time, the switching control means outputs the pulse width modulation signal of the first duty to the motor circuit, and the motor is higher than the known maximum number of revolutions of the motor obtained when the current limiting means applies the current limitation. When the detected rotation speed is low, the pulse width modulation signal of the second duty is output instead of the pulse width modulation signal of the first duty.

According to the sixth aspect of the present invention, the switching control means is a known maximum torque generating duty for generating the maximum torque obtained when the pulse width modulation signal of the first duty is output to the motor circuit. When the first duty is high, the pulse width modulation signal of the second duty is output to the motor circuit at least during low speed rotation.

According to each of the fifth and sixth aspects of the invention, two types of pulses are generated by the switching control means based on the motor rotation speed information or the first duty obtained by the first duty setting means. Switching control of the width modulation signal can be realized.

1 is a block diagram showing a control device for a vehicle motor for driving an electric vehicle. In the figure, the motor 10 is composed of, for example, a DC motor, and the motor circuit 1
When the current generated in 2 is applied, it is driven to rotate.
The motor circuit 12 is configured by connecting the FET 14 and the resistor 16 in series with the motor 10 between the battery power supply and the ground. Also, battery power and FE
A freewheeling diode 18 is connected in parallel with the motor 10 between T14. In this embodiment, a PWM signal is supplied to the gate of the FET 14, and this PWM signal is HIGH.
The FET 14 is turned on for a certain period of time, whereby the battery 10 is energized by the motor 10. Also, FE
When T14 is off, the current generated in the motor 10 is made to flow in one direction by the freewheeling diode 18.

In the present embodiment, the first and second duty setting units 20 and 30 are provided in order to generate the electric current that flows through the motor circuit 12. First duty setting unit 20
Is configured similarly to the conventional duty setting unit 104 shown in FIG. 6, and based on the acceleration command information from the accelerator 22,
As shown in FIG. 7A, the duty of the PWM signal is set larger as the accelerator opening becomes larger. The second duty setting unit 30 is newly added in the present embodiment, and based on the rotation speed information from the rotation speed detecting unit 32 that detects the rotation speed of the motor 10, the second duty setting unit 30 is shown in FIG. The duty is set by changing the indicated pulse width b. The rotation speed detection unit 32 detects the rotation speed of the motor 10 with a rotary encoder, a tacho generator, or the like.

Here, the duty set by the first duty setting section 20 is referred to as a first duty Ad,
The duty set by the second duty setting unit 30 is referred to as a second duty Nd. First duty A
The relationship between d and the accelerator opening is shown in FIG. 7A, while the relationship between the second duty Nd and the rotation speed N is shown in FIG.
As shown in. In FIG. 2, when the rotation speed N = 0, the duty is (Im / Is) ^1/2 and Nd = 1.
The reason why the rotation speed N = Na at the time of 00% is set will be described later.

The control device shown in FIG. 1 has a switching element 4 which selectively outputs the first and second duties.
Has 0. The switching of the switching element 40 is performed based on the output from the comparator 42 which is an example of the switching control means. The comparator 42 inputs the PWM signal output from the first duty setting unit 20 and the PWM signal output from the second duty setting unit 30,
The first and second duties Ad and Nd are compared with each other. The switching control based on the output of the comparator 42 is as follows.

When Nd ≧ Ad, the first duty Ad
The PWM signal of is selected.

When Nd <Ad, the PWM signal of the second duty Nd is selected.

A current limiting circuit 50 is provided between the switching element 40 and the motor circuit 12. The current limiting circuit 50 includes a current limiting section 52 and a current detecting section 54.
Since these respective functions are similar to those of the current limiting unit 106 and the current detecting unit 108 of the conventional device shown in FIG. 10, the description thereof will be omitted. The current detection unit 54 is
By detecting the current between the resistor 16 and the FET 14,
The current flowing through the motor 10 is detected.

Here, the second duty Nd of the PWM signal set by the second duty setting unit 32 is as shown in FIG.
As shown in Equation 1, when this is expressed in a mathematical expression, it is expressed by the following Expression (1).

Nd = [100- (Im / Is) ^1/2 ] ×
N / Na + (Im / Is) ^1/2 (1) Is = Motor lock current when duty is 100% Im = Current limit value Io = No load current No = No load speed N = Motor speed Na = Current Maximum rotational speed at the time of limitation The maximum rotational speed Na at the time of current limitation is expressed by the following equation (2).

Na = −Im × No / (Is
-Io) + No (2) Next, the drive characteristics of the motor drive-controlled by the control device shown in FIG. 1 will be described with reference to FIG. FIG. 3 shows the motor rotation torque T when the motor 10 is driven by the PWM signal having the first duty Ad or the second duty Nd.
And the motor rotation speed N are shown. In FIG. 3, drive characteristics 60 and 62 indicated by solid lines respectively show torque-rotation speed characteristics when the acceleration command information from the accelerator 22 is “fully open”. In this case, the first duty Ad = 100%, and in the high rotation region, as shown by the drive characteristic 60, the PWM having the first duty Ad
A signal is input to the motor 10, and the drive characteristic in this case is the same as that of the conventional device shown in FIG. The difference between the device of the present embodiment and the conventional device is shown in FIG. 3, in the conventional case, when the PWM signal of the first duty Ad is input to the motor in the low-speed rotation and medium-speed rotation regions, the current is limited. Drive characteristic 6
As shown in FIG. 4, the drive torque is limited to Ta. On the other hand, in the device of the present embodiment, the first duty A is
The PWM signal of the second duty Nd is supplied to the motor circuit 12 instead of d. The drive characteristic when the PWM signal of the second duty Nd is supplied to the motor circuit 12 is the drive characteristic 62 of FIG.

Here, the second duty Nd becomes Nd = (Im / Is) ^1/2 by substituting N = 0 in the above equation (1) when the number of revolutions = 0, for example. That is, as shown in FIG. 2, when the rotation speed N = 0, the second duty Nd is not 0 but is set as described above, and thus the current of the current limit value Im is supplied to the motor 10. . As a result, at startup, the maximum torque Tm obtained by the current having the current limit value Im can be obtained.

FIG. 4 is a characteristic diagram showing the relationship between the duty of the PWM signal and the starting torque when the current limit value Im is changed. As shown in the figure, the duty is (I
When set to m / Is) ^1/2 , the starting torque has a peak, and the starting torque at this peak can be changed by changing the current limit value Im. However, how to set the current limit value Im depends on the motor characteristics, and if the current limit value Im is set to a large value, the load on the motor increases and the life thereof is greatly reduced.
The second duty Nd is, as shown in FIG.
The duty is set to be larger as the rotational speed N of 0 becomes higher. Therefore, the second duty setting unit 3
At 0, the second duty Nd is increased according to the rotation speed of the motor 10 detected by the rotation speed detection unit 32, and the drive characteristic obtained at this time is the drive characteristic 62 of FIG. Is. The drive characteristic 62 is such that the current limit value Im is supplied to the motor 10 by supplying the PWM signal of the second duty Nd determined by the rotation speed shown in FIG. 2 to the motor circuit 12, and the maximum at each duty is obtained. Torque can be obtained.

Thus, when the accelerator is fully opened,
In the low speed rotation range and the medium speed rotation range, the motor 10 is driven according to the drive characteristic 62 until the maximum rotation speed Na when the current is limited is reached. When the rotation speed N of the motor 10 reaches the maximum rotation speed Na at the time of current limitation, FIG.
As shown in, the second duty Nd = 100%. Here, when the acceleration command information from the accelerator 22 is “fully open”, the first duty Nd = 100% set by the first duty setting unit 20. Comparator 42
Is the PW of the first duty Ad when Nd ≧ Ad
A switching element 42 selection command is output so as to select the M signal. As a result, when the rotation speed N of the motor 10 is higher than the above-described maximum rotation speed Na, the PWM signal having the first duty Ad is supplied to the motor circuit 12 thereafter. The drive characteristic at this time is the drive characteristic 60 shown in FIG.

As described above, in the device of the present embodiment, the conventional device is subjected to the current limitation, so that the torque when the accelerator is fully opened is limited to the torque Ta shown in FIG. 3 in the low speed rotation region and the medium speed rotation region. On the other hand, in the device of this embodiment, it is possible to secure a rotational torque higher than this. Therefore, the acceleration time is shortened and the grade climbing performance is greatly improved.

Next, the drive characteristics when the first duty Ad is not 100%, in other words, when the acceleration command information from the accelerator 22 is not "fully open" will be described. The drive characteristic 70 shown in FIG. 3 is the PW of the first duty Ad.
When the M signal is supplied to the motor 10, it shows a critical drive characteristic that the current limiting unit 52 does not limit the current. According to the drive characteristic 70, the maximum torque Tm can be obtained when the rotation speed is the minimum. This maximum torque Tm can be achieved by energizing the motor 10 with the current limit value Im. When the first duty Ad is equal to or less than the duty capable of generating the maximum torque Tm (hereinafter, referred to as maximum torque generation duty), the motor 10 is driven as indicated by a characteristic 72 shown by a two-dot chain line in FIG. The PWM signal of the first duty Ad is always supplied to the motor circuit 12 regardless of the number of revolutions N.

On the other hand, when the first duty Ad becomes larger than the maximum torque generating duty, the first and second duties Ad and Nd are selectively used as in the case where the accelerator is fully opened. Become. For example, the drive characteristic when the first duty Ad = X, which is higher than the maximum torque generating duty, is driven by the drive characteristic 80 at a rotation speed higher than the rotation speed Nx, and at the rotation speed lower than the above, It is driven with the driving characteristic 62 of.
The rotational speed Nx is the motor 10 obtained when the PWM signal in which the duty of the first duty Ad = X% is set is output to the motor circuit 12 and the current limiting unit 52 receives the current limitation. Is the maximum rotation speed of.

From the above, instead of the comparator 42 as the switching means shown in FIG. 1, as shown in FIG. 5, switching is performed based on the information from the rotation speed detecting section 32 and the first duty setting section 20. It can also be configured as a switching control unit 90 that controls switching of the element 40.

The switching control section 90 stores, for example, the above-mentioned maximum torque generating duty, and the first duty A set by the first duty setting section 30.
When d is less than or equal to this maximum torque generating duty, the PWM signal having the first duty Ad set by the first duty setting unit 20 is constantly applied to the motor circuit 12
The switching control is performed so that the power is supplied to.

When the first duty Ad is larger than the maximum torque generating duty, the following two-step control is performed. At this time, the motor 10
When the rotation speed N is smaller than the maximum rotation speed Nx at the time of current limitation, the PWM signal having the second duty Nd set by the second duty setting unit 30 is input to the motor 10. Supply to. Conversely, when the actual rotation speed N is higher than the maximum rotation speed Nx, the first duty Ad set by the first duty setting unit 20 is set.
The PWM signal having the above is stored in the output to the motor circuit 12.
This rotation speed Nx is a rotation speed uniquely determined by a certain duty X, and the switching control unit 90 may have a table in which the first duty Ad and the rotation speed Nx are associated with each other. Alternatively, the rotational speeds at arbitrary two points on the drive characteristic 62 of FIG. 3 and the duty corresponding thereto are stored, and the rotational speed Nx at a certain duty X is linearly interpolated based on the first duty Ad. It can also be calculated from

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the gist of the present invention.

For example, in FIG. 2, the characteristic of the second duty Nd is the second duty Nd = (Im / Is) ^1/2 when the rotation speed N = 0, but the present invention is not limited to this. is not. This value is a value set in order to obtain a larger rotational torque in the drive characteristic 62 shown in FIG. 3, and is set within a range in which the second duty Nd does not exceed (Im / Is) ^1/2. By setting a value closer to, the best rotation torque can be obtained.

Further, the motor 10 to be controlled by the control device of this embodiment is not limited to the DC motor,
Similarly, it can be applied to a brushless motor or the like that is driven and controlled by a PWM signal.

Furthermore, the signal supplied to the motor circuit 12 is not limited to the PWM signal described above, but may be an analog signal whose analog amount is determined according to the accelerator opening or the motor rotation speed.

Furthermore, the second duty N shown in FIG.
The characteristics of d and the characteristics of the first duty Ad shown in FIG. 7A are not limited to the linear characteristics as shown in the respective drawings, but may be set to characteristics that curve and change from low duty to high duty. .

The first duty Ad shown in FIG. 7 (A) is set to 100% of the accelerator opening and 100% of the duty, but other settings such as the accelerator opening of 10 are set.
The duty can be changed to 0% at 80%.

[0041]

As described above, according to the inventions of claims 1 to 6, unlike the conventional apparatus in which the motor is drive-controlled by the signal generated based only on the acceleration command information, the actual motor Even when the acceleration command information that is excessively high with respect to the rotation speed is input, the current limitation by the current limiting means is reduced. As a result, the rotational torque does not drop extremely during acceleration or climbing, and the acceleration characteristics and climbing performance can be greatly improved. In particular, as in the invention of claim 4, the pulse width modulation signal having the second duty is set so that a current which is substantially close to the current limit value is always flowed to the motor regardless of the number of rotations of the motor. The optimum drive torque can be secured at the time of climbing or when climbing a slope, and stable control can be performed while keeping the average current flowing through the motor substantially constant.

[0042]

[Brief description of drawings]

FIG. 1 is a block diagram of a motor control device for an electric vehicle to which the present invention is applied.

FIG. 2 is a characteristic diagram showing a relationship between a second duty and a motor rotation speed.

FIG. 3 is a drive characteristic diagram of rotational torque-rotation speed achieved by the control device of FIG.

FIG. 4 is a characteristic diagram showing a duty-starting torque relationship obtained by the control device of FIG. 1.

5 is a block diagram showing a modification of the switching control means shown in FIG.

FIG. 6 is a block diagram of a conventional motor control device.

FIG. 7A is a characteristic diagram showing a relationship between a first duty (duty based on acceleration command information) and an accelerator opening degree, and FIG. 7B shows an example of a pulse width modulation signal. It is a waveform diagram.

FIG. 8 is a characteristic diagram showing a relationship between rotational torque and rotational speed when the current is not limited.

FIG. 9 is a characteristic diagram showing a rotational torque-rotational speed relationship when a current is limited.

[Explanation of symbols]

 10 Motor 12 Motor Circuit 14 FET 20 First Duty Setting Section 22 Accelerator 30 Second Duty Setting Section 32 Rotation Speed Detection Section 40 Switching Element 42 Comparator 50 Current Limiting Circuit 52 Current Limiting Section 54 Current Detection Section 90 Switching Control Section

Claims (6)

[Claims] 1. A control device for a vehicle motor that drives and controls a vehicle motor based on a signal input to a motor circuit, wherein a first signal input to the motor circuit is based on acceleration command information. First signal setting means for setting and outputting, rotation speed detecting means for detecting the rotation speed of the motor, and second signal input to the motor circuit based on the rotation speed information of the motor. Second signal setting means for selectively outputting the first and second signals, and switching means for selectively outputting the first or second signal, and detecting a current flowing through the motor to set a preset current limit value. By changing the signal from the switching means and outputting it to the motor circuit when the detected current exceeds the current limit means for limiting the current flowing to the motor, and outputting the first signal to the motor circuit. A control device for a vehicle motor, comprising: a switching control unit that controls switching to the second signal by the switching unit when the current limiting unit receives a current limit. 2. A vehicle motor control device for driving and controlling a vehicle motor based on a pulse width modulation signal input to a motor circuit, wherein a first duty of the pulse width modulation signal is used as acceleration command information. First duty setting means for setting and outputting based on rotation information of the motor, second duty setting means for setting and outputting based on rotation information of the motor, Switching means for selectively switching and outputting the pulse width modulation signal of the first or second duty; and a switching means for detecting a current flowing through the motor and detecting a current exceeding a preset current limit value. A current limiting means for changing the duty of the pulse width modulation signal from the motor and outputting the pulse width modulated signal to the motor circuit to limit the current flowing through the motor; And a switching control means for controlling the switching means to switch to the pulse width modulation signal of the second duty when outputting the pulse width modulation signal of the duty to the motor circuit and receiving the current limitation. A control device for a motor for a vehicle. 3. The vehicle motor according to claim 2, wherein the switching control means compares the first duty and the second duty and outputs the pulse width modulation signal having a small duty. Control device. 4. The motor according to claim 2 or 3, wherein the second duty is a current equal to or less than the current limit value and a current near the current limit value when the rotation speed of the motor is zero. A vehicle motor control device, wherein the duty is set to generate a maximum torque obtained when the vehicle is energized. 5. A vehicle motor control device for driving and controlling a vehicle motor based on a pulse width modulation signal input to a motor circuit, wherein a first duty of the pulse width modulation signal is used as acceleration command information. First duty setting means for setting and outputting based on rotation information of the motor, second duty setting means for setting and outputting based on rotation information of the motor, Switching means for selectively switching and outputting the pulse width modulation signal of the first or second duty; and a switching means for detecting a current flowing through the motor and detecting a current exceeding a preset current limit value. Limiting means for limiting the output current from the motor circuit, the pulse width modulated signal of the first duty being output to the motor circuit, and the current limiting means. When the detected rotation speed of the motor is lower than the known maximum rotation speed of the motor obtained when the flow is restricted, the switching means controls the switching to the pulse width modulation signal of the second duty. A control device for a vehicle motor, comprising: switching control means; 6. A vehicle motor control device for driving and controlling a vehicle motor based on a pulse width modulation signal input to a motor circuit, wherein a first duty of the pulse width modulation signal is used as acceleration command information. First duty setting means for setting and outputting based on rotation information of the motor, second duty setting means for setting and outputting based on rotation information of the motor, Switching means for selectively switching and outputting the pulse width modulation signal of the first or second duty; and a switching means for detecting a current flowing through the motor and detecting a current exceeding a preset current limit value. Limiting means for limiting the output current from the motor, and a maximum torque obtained when the pulse width modulation signal of the first duty is output to the motor circuit. When the first duty is higher than the known maximum torque generating duty, switching control means for performing switching control to the pulse width modulation signal of the second duty by the switching means at least during low-speed rotation, A control device for a vehicle motor, which is provided.