JPH06113406A - Control method of electric motor drive control device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a control method of an electric motor drive control device capable of controlling the riding comfort of a vehicle or the like in a steady state so as to match human sensitivity. In a drive control device for an electric vehicle or the like that controls the torque of an electric motor to transmit thrust to driving wheels, a power spectrum density is inversely proportional to a frequency in response to a current command given by a thrust setter or a driver. This is a control method for an electric motor drive control device, which controls the electric current of the electric motor by a new electric current command obtained by adding the electric current components, and controls the torque of the electric motor by the electric current control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an electric motor such as an elevator and an electric car driven by a DC or AC electric motor, and more particularly to a method for controlling an electric motor drive control device that gives passengers a good riding comfort.

[0002]

2. Description of the Related Art FIG. 3 is a diagram for explaining a conventional general electric vehicle drive system. 1 is an AC motor, 2 is an inverter for driving the AC motor 1, 3 is a driving wheel,
Generally, it is connected to a motor shaft by a gear (not shown). Reference numeral 4 is a resistor for giving a thrust command, and 5 is a thrust-current converter, which converts the thrust command into a current command and compares the input current of the inverter 2 detected by the current transformer CT with the comparator 10.
Compare in. The current deviation signal of the comparator 10 is given to the current controller 6 through the limiter 8. The output of the current controller 6 is a voltage command given to the inverter 2, and PW
The control timing of the inverter is determined by the M controller 7.

FIG. 4 is a diagram for explaining the relationship between the current controller 6 and the inverter 2. FIG. 4 (a) is a diagram showing an example of the configuration of the inverter 2, and the DC voltage E is the capacitor C.
The gate turn-off thyristor (GTO) S is divided by capacitors C1 and C2 in parallel with capacitors C1 and C2, respectively.
A series circuit of 1 and S2 is connected. Further, the winding of the AC motor is connected between the midpoints of the capacitors C1 and C2 and the midpoints of the thyristors S1 and S2, which is indicated by the symbol of the transformer T in the figure.

FIG. 4B is a diagram for explaining the operating principle of the inverter 6. For example, when a sinusoidal voltage command is given, it is compared with a high frequency triangular wave carrier (triangular wave carrier). Then, on / off of the thyristors S1 and S2 is determined by the magnitude relation between the two. Voltage command> carrier wave; S1 is on, S2 is off Voltage command <carrier wave; S2 is on, S1 is off

At the output of the inverter 2, that is, at both ends of the transformer T, a voltage as shown in the lower side of FIG. 4B appears. In this figure, the shaded portion shows the region where S1 is on, and the other portion shows the region where S2 is on. The voltage of the pulse train may have a fundamental wave similar to the voltage command. Are known.

Here, a problem when the configuration of FIG. 3 is applied to an electric vehicle will be described. It is the torque of the electric motor that controls the thrust of the electric vehicle, for which the input current of the inverter is controlled. The current deviation that is the output of the comparator 10 is
A correction amount of electric current for matching the propulsive force of the electric vehicle with the command value given by the resistor 4 is given. If this current deviation is large, a large acceleration or deceleration will be applied to the vehicle, and the riding comfort will be very poor. Therefore, the limiter 8 suppresses the thrust suddenly and limits the acceleration / deceleration applied to the vehicle to prevent the deterioration of the riding comfort. In some cases, not only a limiter but also a rate of change of current may be specified.

[0007]

As described above, FIG.
In this drive system, the ride comfort is kept good by limiting the vehicle acceleration. This method
Physically, smooth acceleration / deceleration is performed, and when traveling at a constant speed, it is driven with constant thrust, and it seems that it will perform ideal movement, but there is no compensation that it matches the sensation of passengers received by it. . It has been demanded to improve the riding comfort of a vehicle by incorporating a control method suitable for human sensitivity in addition to the conventional physical smoothness. An object of the present invention is to provide a control method of an electric motor drive control device capable of controlling the riding comfort of a vehicle or the like in a steady state so as to match human sensation.

[0008]

In order to achieve the above object, the invention according to claim 1 is a drive control device for an electric vehicle or the like for controlling torque of an electric motor to transmit thrust to drive wheels. Current control of the electric motor by a new current control command obtained by adding a current component such that the power spectrum density is inversely proportional to the frequency to the current control command given by the electric motor or driver, and the torque of the electric motor is controlled by this current control. Is a control method of an electric motor drive control device.

In order to achieve the above object, the invention according to claim 2 provides a drive control device for an electric vehicle or the like for controlling the torque of an electric motor to transmit the thrust to the driving wheels, by a thrust setting device or a driver. The frequency command of the current is proportional to the (-n) th power of the frequency, and n
The current control of the electric motor is performed by a new current command obtained by adding the current components in the range of 0.65 to 0.35, and the torque of the electric motor is controlled by the current control. It is a control method of an electric motor drive control device.

[0010]

According to the inventions corresponding to claims 1 and 2, in addition to the conventional physical smoothness, a thrust command appealing to human sensibilities can be given, so that the ride comfort of a vehicle is improved. It becomes possible to do. Specifically, "fluctuation" is said to give humans the most natural feeling in the thrust command.
This is because the component of (3) is mixed in so as to control the ride comfort not only during acceleration / deceleration but also during steady operation so as to match human sensitivity.

The above-mentioned "fluctuation" is found in all phenomena in nature such as sound, light and physical movement. As a human sense, no matter what I do, the monotonous movement makes me tired and uncomfortable. On the other hand, totally random movements do not match the information that humans have already learned through experience,
This also feels uncomfortable. For humans, the most satisfying feeling can be obtained when the expectation and the appropriateness are correlated with the past. Theoretically, if the power spectral density (root mean square of the fluctuation) is proportional to f ^-2 with respect to frequency, it will be a monotonous movement, and f ⁰ When it is proportional to, it becomes a random movement like white noise. It is said that most things in the natural world are in proportion to f ^-1 , which gives humans a feeling of comfort. The present invention incorporates the idea of “fluctuation” as described above into the driving control of a vehicle or the like.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a control method for an electric motor drive controller according to the present invention will be described below with reference to the drawings. Figure 1
FIG. 3 is a diagram for explaining the first embodiment of the present invention,
Reference numeral 1 is an AC electric motor, 2 is an inverter for driving the AC electric motor 1, 3 is a driving wheel, and is generally connected to a motor shaft by a gear (not shown). Reference numeral 4 is a resistor for giving a thrust command, and 5 is a thrust-current converter, which converts the thrust command into a current command and compares it with the input current of the inverter 2 detected by the current transformer CT in the comparator 10. In this comparator 10, the current deviation signal obtained is the limiter 8
Through the current controller 6. The output of the current controller 6 is a voltage command given to the inverter 2, and the PW
The control timing of the inverter is determined by the M controller 7. This basic operation is the same as in FIGS. 3 and 4 described above.

The current deviation, which is the output of the comparator 10, gives a correction amount of the current for making the propulsive force of the electric vehicle match the command value given by the adder 11. If the current deviation is large, a large acceleration or deceleration will be applied to the vehicle, resulting in a very uncomfortable ride. Therefore, the limiter 8 suppresses a sudden change in thrust and limits the acceleration / deceleration applied to the electric vehicle to prevent deterioration of the riding comfort. In some cases, instead of the limiter 8, the rate of change of the current command may be specified. By appropriately selecting the limiter 8, it is possible to obtain a good ride comfort due to acceleration / deceleration of the vehicle.

In the first embodiment of the present invention, in order to realize thrust control which gives a comfortable feeling to human beings by mixing the fluctuation component into the current command value at the time of steady (low speed) operation,
A fluctuation signal synthesis circuit 9 described below is provided.

The fluctuation signal synthesis circuit 9 includes a proportional element 91,
It is composed of 92, 93, 94, an adder 12, and a coefficient converter 95. Proportional elements 91, 92, 93, 94
Input unit sine waves V ₁ , V ₁₀ , V ₁₀₀ , and V ₁₀₀₀ having frequency components of ₁ , ₁₀ , ₁₀₀ , and ₁₀₀₀ Hz, respectively, and multiply each input value by the magnitude of the gain that has been set in advance. Output the value. The adder 12 adds the outputs of the proportional elements 91 to 94 and outputs a fluctuation signal (a signal including current fluctuations of various frequency components). The coefficient converter 95 guides the output signal of the adder 12 and outputs the conversion coefficient obtained by performing a predetermined coefficient conversion here.

The adder 11 outputs the fluctuation signal synthesizing circuit 9, that is, the output of the coefficient converter 95 and the thrust-current converter 5.
Of the current of the inverter 2 detected by the current transformer CT and the current command obtained by the addition, the current deviation signal is obtained in the comparator 10.

As described above, the power spectral density is f
^-1Is proportional to
It becomes like 2. The horizontal axis is log (f) and the vertical axis is log
The inclination is -1 in {S (f)}. -1 straight line
There are innumerable numbers, and from the state shown in Fig. 2, both vertically and horizontally.
You can slide it in various ways. Power spect
The frequency density of the
Mainly what kind of ingredients should be mixed
Determined by experience. Power spectral density is different
In other words, it is “root mean square of fluctuation”. S (f)
Is the frequency component of the current, S (f) = Δi (f)²  Have a relationship. Set the magnitude of 1kHz component to 1
When the wave number component is obtained, the relationship between the frequency component and the magnitude of the current
Is as follows. When f = 1000, S (f) = 1, Δi (f) = 1 When f = 100, S (f) = 10, Δi (f) = 3.
16 f = 10, S (f) = 100, Δi (f) = 10 f = 1, S (f) = 1000, Δi (f) = 3
1.6

In order to include these fluctuation components in the propulsion current command, the frequencies 1, 10, 100, 1 as shown in FIG.
Unit sine waves of 000 Hz component V ₁ , V ₁₀ , V ₁₀₀ ,
Each of V ₁₀₀₀ is input to the proportional elements 91, 92, 93, 94, multiplied by the magnitude of the gain that has already been set, and added by the adder 12. Since the output of the adder 12 becomes a fluctuation signal including current fluctuations of various frequency components, it is guided to the coefficient converter 95 and its output signal is sent to the adder 11. The current command combined by the adder 11 includes a DC component from the resistor 4 that gives a thrust command and an AC component from the fluctuation signal combining circuit 9. The direct current component in this case is, so to speak, an average current, and the alternating current component slightly moves the current around the average current, so that it does not cause boredom and also gives discomfort to humans. It provides thrust fluctuations that are not such current fluctuations to provide a comfortable ride.

The effect of adding such an AC component is easy to understand when it is considered by replacing it with driving a car. That is, when driving a car at a constant speed, if the speed is kept constant by auto cruising, you get tired of it, but maintaining the speed while subtly changing the target speed is a tireless driving. There is something in common with that.

Next, a second embodiment of the present invention will be described. In the above-described embodiment, the average thrust is selected by selecting the gain K _{1 of} the thrust-current converter 5 for converting the thrust command into current and the conversion coefficient K ₂ of the coefficient converter 95 at the final stage of the fluctuation signal synthesizing circuit 9. The ratio of fluctuation to the value can be determined. The decision depends largely on experience, but there are some individual differences. The human sense is more sensitive to subtle vibrations at lower speeds. As the speed increases to a certain extent, the factors that are determined by the inertia of the electric vehicle or vehicle increase. Therefore, the effect of such fluctuations can be strengthened at low speeds and weakened at high speeds. In this way, the effect of fluctuation may be variable depending on the operating conditions.

The third embodiment of the present invention will be described. That is, although it is best to make the power spectrum density inversely proportional to the frequency, the fluctuation signal synthesizing circuit 9
As a result of constructing, the frequency may not be exactly divided by the frequency (f). It has both soft and hardware limits, and various frequency components may be mixed in the synthesis process of the fluctuation signal synthesis circuit 9. Considering such a thing, it is necessary to allow about f ^{-1.3 to} f ^-0.7 even if aiming at f ^-1 .

It has been taught that constant thrust operation is unconditionally good in conventional electric vehicle control. Therefore, it is attempted to improve the ride comfort by suppressing sudden changes in acceleration and deceleration and aiming for smooth driving at both corners. However, when it comes to human perception, mere smoothness is not enough. There are aspects that humans do not like to change, in other words, expectations that they want to continue their current exercise, and aspects that they prefer to exercise with some unexpectedness. In order to realize this, an element in which the power spectral density is inversely proportional to the frequency is incorporated, and the present invention provides a method for controlling an electric motor that gives human satisfaction while always maintaining a commanded speed.

[0023]

As described above, according to the present invention, it is possible to provide a control method of an electric motor drive control device capable of controlling the riding comfort of a vehicle or the like in a steady state so as to match the human sense.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an embodiment of an electric vehicle control system of the present invention.

FIG. 2 is a diagram showing an example of a power spectral density for explaining FIG.

FIG. 3 is a diagram showing an example of drive control of a conventional electric vehicle.

FIG. 4 is an auxiliary diagram for explaining FIG. 3 and a diagram for explaining an inverter and its control method.

[Explanation of symbols]

1 ... motor, 2 ... inverter, 3 ... driving wheel, 4 ... speed setting device, 5 ... thrust-current converter, 6 ... current controller, 7 ... P
WM controller, 8 ... Limiter, 9 ... Fluctuation signal synthesis circuit,
10 ... Comparator, 11, 12 ... Adder.

Claims (2)

[Claims] 1. In a drive control device for an electric vehicle or the like that controls the torque of an electric motor to transmit thrust to driving wheels, a power spectrum density is inversely proportional to a frequency in response to a current command given by a thrust setter or a driver. A method for controlling a motor drive control device, characterized in that current control of the motor is performed by a new current command obtained by adding such current components, and torque of the motor is controlled by this current control. 2. In a drive control device for an electric vehicle or the like, which controls the torque of an electric motor to transmit thrust to driving wheels, the current frequency spectrum has a frequency (- n) The electric current of the electric motor is controlled by a new electric current command obtained by adding the electric current components proportional to the nth power and in the range of n = 0.65 to 0.35. A method for controlling an electric motor drive control device, comprising controlling torque.