HK1164801A - Controller for electric vehicle - Google Patents

Description

Control device for electric vehicle

The present invention is a divisional application of an invention patent application having an international application number of PCT/JP2007/062930, an international application date of 2007, 27.6.2007, and an application number of 200780053440.1 entitled "control device for electric vehicle" entering the chinese national phase.

Technical Field

The present invention relates to a control device for an electric vehicle, and more particularly to a control device for an electric vehicle having an idle running control function for suppressing idle running and sliding of wheels.

Background

As a control device of an electric train, a system that drives and controls an alternating-current motor using an inverter has been put to practical use. It is known that acceleration and deceleration of a railway vehicle are achieved by mutual transmission of force in only a small contact area between an iron rail and an iron wheel, and a control device for an electric car needs to appropriately control the torque of an electric motor so that the wheel does not spin. That is, if the torque is too large, the wheel spins, the friction coefficient (hereinafter also referred to as the adhesion coefficient) between the wheel and the rail is reduced, and the force transmission efficiency is reduced. As a result, the acceleration performance of the electric train is deteriorated, and the wheels and the rails are worn. On the other hand, if the torque is too small, the wheels do not spin, but the acceleration performance of the electric train is deteriorated, and it is difficult to travel on the schedule of operation. In addition, the same problem occurs in the case of regenerative braking.

Conventionally, a control device for an electric train has an idling control system for suppressing the idling phenomenon of the wheels as described above. The motor is generally configured to determine an idling state of a wheel by using a change rate of a wheel speed or a speed deviation between a plurality of wheels, and adjust a torque of the motor. However, there are cases where rain, snow, sand, oil, or the like is present between the rail and the wheel, and further, the adhesion coefficient is constantly changed largely depending on the surface state, temperature, running speed, and the like of the rail or the wheel, and the physical phenomenon is complicated, and it is not easy to shape the control rate. Therefore, many systems are known which are configured based on theoretical studies from various viewpoints and running test data of an actual vehicle (see, for example, patent document 1).

Patent document 1: japanese patent laid-open No. 6-335106

Disclosure of Invention

Problems to be solved by the invention

However, the above-described prior art has the following problems. Since the rate of change of the speed of the wheels is relatively large when idling or sliding occurs on a general railway such as a conventional railway line, and the speed deviation between a plurality of wheels is also relatively large, it is easy to grasp the idling/sliding phenomenon from the rate of change of the speed of the wheels and the speed deviation between the wheels. However, when the vehicle travels at high speed on a high-speed railway (for example, approximately 200km/h or more), the rate of change in the speed of the wheels during the occurrence of spin/skid is small, and the speed variation among the plurality of wheels is also small. Therefore, there are problems in that: it is difficult to grasp the spin/skid phenomenon from the rate of change in the speed of the wheels and the speed variation between the wheels, and it is difficult to distinguish between an acceleration state during normal running and a spin/skid state.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a control device for an electric train that can detect an idling/coasting phenomenon particularly during high-speed traveling and can perform appropriate idling/coasting control.

Means for solving the problems

In order to solve the above problems and achieve the object, a control device for an electric vehicle according to the present invention includes a plurality of motors and an idle-run coasting control unit that generates a torque command value based on rotation speeds of the plurality of motors to suppress idling or coasting, the control device for an electric vehicle including: a reference rotation speed calculation unit that calculates a first reference rotation speed and a second reference rotation speed from rotation speeds of the plurality of motors; a first adhesion index generating unit that is provided in association with each of the motors, and generates a first adhesion index that is an index of adhesion between a wheel and a tread surface of the wheel coupled to each of the motors, based on an acceleration deviation that is a difference between an acceleration calculated from a rotational speed of each of the motors and an acceleration calculated from the first reference rotational speed, and a speed deviation that is a difference between a rotational speed of each of the motors and the first reference rotational speed, with the first reference rotational speed and the rotational speed of each of the motors as inputs; a second tackiness index generation unit that generates, as a second tackiness index value, a value obtained by multiplying the first tackiness index value by a gain generated based on the acceleration calculated from the second reference rotation speed, with the second reference rotation speed as an input; and a torque command value generation unit that generates the torque command value based on the second adhesion index value.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, even when the acceleration deviation and the speed deviation are small as in the case of idling or coasting during high-speed running and the idling or coasting control is not effective by adjusting the torque based on the first adhesion index, the idling or coasting control can be appropriately performed by setting the gain generated by the second adhesion index generation unit to a predetermined value smaller than 1. Thus having the effect of: the idle/coasting phenomenon can be grasped only from the rotational speed information of the drive shaft connected to the wheel without adding new rotational speed information of the non-drive shaft or the like, and the idle/coasting state can be detected and appropriate idle/coasting control can be performed before the speed greatly differs from the actual value.

Drawings

Fig. 1 is a diagram showing a configuration of a control device for an electric train according to an embodiment.

Fig. 2 is a diagram showing a configuration of an idle rotation control unit according to the embodiment.

Fig. 3 is an operation diagram of the speed deviation DFM, the acceleration deviation DFT, and the adhesion index ADL1 when the wheel 5A coupled to the first shaft spins.

Fig. 4 is an operation diagram of the adhesion indexes ADL1 to ADL4 of the respective axes, the adhesion index ADL0 when the maximum value processing is performed, the torque command T0 at the steady state, and the torque command T adjusted by the idling control.

Fig. 5 is an operation diagram of the first tackiness index calculation section 7A when the slight idling continues.

Fig. 6 is an operation diagram of FM1 to FM4, FMmax, ADL0, S1, S2, ADL, T0, and T when the second tackiness index calculation unit is activated.

Description of the reference symbols

1 idle running control part

2 torque calculating part

3 power converter

4A-4D motor

5A-5D wheel

6 track

7A-7D first tackiness index generating section

8 second tackiness index Generation section

9 maximum calculator

10 minimum calculator

11. 13, 19 differentiator

12 reference rotational speed calculating section

14. 16 subtraction arithmetic unit

15. 17, 20 low pass filter

18 discriminator

21 comparator

22. 23 inverter

24-off delayer

25ADL processing unit

26. 27 multiplication arithmetic unit

28 first order delay part

29 acceleration calculating part

30 acceleration deviation processing part

31 differential speed deviation processing part

32 acceleration low-response processing unit

33 idle running detection part

34 gain generating part

35 time constant setting part

Detailed Description

An embodiment of a control device for an electric train according to the present invention will be described in detail below with reference to the drawings. The present invention is not limited to the present embodiment. In addition, although the idle control is described, the coasting control is also the same.

Detailed description of the preferred embodiments

Fig. 1 is a diagram showing a configuration of a control device for an electric train according to the present embodiment. Fig. 2 is a diagram showing a configuration of an idle rotation control unit according to the present embodiment.

First, a configuration of a control device for an electric train according to the present embodiment will be described with reference to fig. 1. Reference numeral 1 denotes a control unit that performs torque control to eliminate an idling state or a coasting state, and for simplification of the description, the control unit is simply referred to as an idling control unit. The idling control unit 1 receives a torque command value T0 during non-idling, adds an idling state to the torque command value T0, and calculates the idling state, and then outputs the torque command value T. Reference numeral 2 denotes a torque calculation unit which receives T as an input and outputs a gate control output G. Reference numeral 3 denotes a power converter, which controls the power converter based on a gate control output G of the output of the torque calculation unit 2, and drives the plurality of motors 4A to 4D collectively in the illustrated example.

Reference numerals 5A to 5D denote wheels, and reference numeral 6 denotes a rail. The motors 4A to 4D are connected to the shafts of the wheels 5A to 5D, respectively, and rotate the wheels 5A to 5D. The electric vehicle obtains a propulsive force by the rotation of the wheels 5A to 5D by using a frictional force between the wheels 5A to 5D and the rail 6. FM1 to FM4 indicate the rotation speed of the shaft of each of the motors 4A to 4D by using a speed signal detected by a sensor (not shown) provided for each of the motors 4A to 4D.

Next, the configuration of the idling control unit 1 will be described with reference to fig. 2. Reference numerals 7A to 7D denote first adhesion index generating units which generate adhesion indexes ADL1 to ADL4 which are indices of the adhesion between the wheels 5A to 5D and the rail 6, respectively. Reference numeral 8 denotes a second adhesion index generating unit provided separately from the first adhesion index generating units 7A to 7D. Reference numeral 9 denotes a maximum value calculator for the maximum value FMmax of the output rotation speeds FM1 to FM4, and reference numeral 10 denotes a minimum value calculator for the minimum value FMmin of the output rotation speeds FM1 to FM 4. The maximum value calculator 9 and the minimum value calculator 10 are provided inside the reference rotational speed calculation unit 12. The reference rotation speed calculation unit 12 outputs FMmin to the first adhesion index generation units 7A to 7D, and outputs FMmax to the second adhesion index generation unit 8. In the present embodiment, the reference rotation speed calculation unit 12 calculates the minimum value FMmin and the maximum value FMmax from the rotation speeds FM1 to FM4, but the present invention is not limited thereto, and 2 reference rotation speeds may be generated from the rotation speeds FM1 to FM 4.

The 2 signals FMmin and rotation speed FM1 are input to the first tackiness index generation unit 7A. Similarly, 2 signals of FMmin and rotation speed FM2 are input to the first adhesion index generation unit 7B, 2 signals of FMmin and rotation speed FM3 are input to the first adhesion index generation unit 7C, and 2 signals of FMmin and rotation speed FM4 are input to the first adhesion index generation unit 7D. FMmax is input to the second tackiness index generation unit 8.

Next, the first tackiness index generation unit 7A will be described. The same applies to the first tackiness index generation units 7B to 7D. Reference numeral 11 denotes a differentiator, which receives the rotation speed FM1 as an input and outputs an acceleration a1, which is a time rate of change of FM 1. Reference numeral 13 denotes a differentiator, which receives Fmmin as an input and outputs acceleration a2, which is a time rate of Fmmin. The differentiator 11 and the differentiator 13 constitute an acceleration calculating unit 29 as a first acceleration calculating unit. Reference numeral 14 denotes a subtraction operator, and outputs A3 of a2-a1 from the acceleration a1 and the acceleration a 2. Reference numeral 15 denotes a low-pass filter, which has a3 as an input and outputs an acceleration deviation DFT. The calculation sample of the differentiator 11 is set to be short, and the calculation sample of the differentiator 13 is set to be long. The subtractor 14 and the low-pass filter 15 constitute an acceleration deviation processing unit 30.

Numeral 16 denotes a subtractor which outputs the difference between the rotational speeds FM1 and FMmin as a speed difference V1. Reference numeral 17 denotes a low-pass filter, which receives the speed difference V1 as an input and outputs a speed deviation DFM. The subtractor 16 and the low-pass filter 17 constitute a differential degree deviation processing unit 31.

In the above configuration, the acceleration a1 is the acceleration of the rotational speed FM1 of the first shaft, which is the shaft of the motor 4A, and is the instantaneous acceleration. On the other hand, the acceleration a2 is the acceleration of the minimum rotation speed FMmin among the wheels 5A to 5D, and is a reference acceleration that hardly changes instantaneously. As described above, since the calculation sample of the differentiator 13 is set to be long, the acceleration a2 hardly changes instantaneously and can be used as the reference acceleration. The acceleration a2 is used as a reference acceleration, and A3, which is the difference between the reference acceleration and the instantaneous acceleration a1, is subjected to first order delay processing by the low-pass filter 15 to obtain an acceleration deviation DFT. On the other hand, a first-order delay processing is performed on the speed difference V1, which is the difference between the rotation speeds FM1 and Fmmin of the first axis, by the low-pass filter 17, to obtain a speed deviation DFM.

Reference numeral 18 denotes a discriminator which takes as input the acceleration deviation DFT and the velocity deviation DFM and uniquely outputs the adhesion index ADL1 with respect to the first axis according to the combination of their input values. That is, the determiner 18 determines the adhesion state based on the acceleration deviation DFT and the speed deviation DFM, and outputs an adhesion index ADL1 indicating the adhesion state, for example, by weighting the acceleration deviation DFT and the speed deviation DFM at a predetermined ratio.

Fig. 3 is an operation diagram of the speed deviation DFM, the acceleration deviation DFT, and the adhesion index ADL1 when the wheel 5A coupled to the first shaft spins. The horizontal axis represents time changes of the rotation speeds FM1 to FM4, the speed deviation DFM, the acceleration deviation DFT, and the adhesion index ADL 1. At times t1 to t4, the deviation of at least one of the velocity deviation DFM and the acceleration deviation DFT becomes large, and accordingly, the adhesion index ADL1 is smaller than 1. In particular, it is known from ADL1 between times t2 and t3 that the influence of the acceleration deviation DFT is dominant over the velocity deviation DFM. When the adhesion index is 1, it is determined that the vehicle is not idling, and as the adhesion index is gradually decreased from 1, it is determined that idling is gradually generated.

The same process is also performed on the first tackiness index generation sections 7B to 7D, and tackiness indexes ADL2 to ADL4 can be obtained, respectively.

Reference numeral 25 denotes an ADL processing unit, to which the outputs of the first adhesion index generating units 7A to 7D are input. That is, the adhesion indexes ADL1 to ADL4 are input to the ADL processing unit 25, subjected to, for example, maximum value selection processing or averaging processing, and output as the adhesion indexes ADL 0. Here, the maximum value selection process is a process of selecting an index value having the largest change from 1 to the adhesion indexes ADL1 to ADL4, and the averaging process is a process of selecting an average value of the adhesion indexes ADL1 to ADL 4.

Reference numerals 26 and 27 denote multiplication operators, respectively, and reference numeral 28 denotes a first-order delay section that generates a first-order delay. Let τ be the time constant used in the first-order delay unit 28. As described later, the adhesion index ADL0 output from the ADL processing unit 25 is multiplied by a gain in the multiplier 26, and then multiplied by a steady-state torque command T0 based on the operation command in the multiplier 27, and then input to the first-order delay unit 28, subjected to the first-order delay, and output as the torque command T from the idling control unit 1.

The adhesion index ADL0 is 1 in the state without idling, but since the combination of the values of the acceleration deviation DFT and the speed deviation DFM becomes a value of 1 or less in the idling state, T0 × T and the torque decreases (T0 × T). The time constant for the reduction or restoration can be adjusted by the time constant τ of the first-order delay unit 28.

Fig. 4 is an operation diagram of the adhesion indexes ADL1 to ADL4 of the respective axes, the adhesion index ADL0 when the maximum value selection processing is performed, the torque command T0 at the steady state, and the torque command T adjusted by the idling control. As shown in fig. 4, the torque command T is output in accordance with a change in the adhesion index ADL 0.

In the above operation, the acceleration deviation DFT can be set so as to dominate the responsiveness of the idle control, and the response speed or resolution of the reference acceleration is finely adjusted so as to converge the acceleration deviation, so that the high-speed and fine adhesion control can be performed using the speed deviation DFM and the acceleration deviation DFT.

In the present embodiment, the ADL processing unit 25 outputs 1 adhesion index ADL0 and outputs the torque command T corresponding to the adhesion index ADL0 based on the adhesion indexes ADL1 to ADL 4. That is, the torques of the 4 motors 4A to 4D are collectively controlled by the torque command T. Alternatively, 4 torque commands corresponding to the adhesion indexes ADL1 to ADL4 may be output without using the ADL processing unit 25, and the torques of the 4 motors 4A to 4D may be individually controlled by the 4 torque commands.

Next, the second tackiness index generation unit 8 will be described. Reference numeral 19 denotes a differentiator which receives FMmax output from the maximum value calculator 9 as an input and outputs an acceleration S1. Reference numeral 20 denotes a low-pass filter, which receives the acceleration S1 as an input and outputs an acceleration S2. The differentiator 19 and the low-pass filter 20 constitute an acceleration low-response processing unit 32 as a second acceleration calculating unit. That is, the acceleration S2 of the output of the acceleration low response processing unit 32 does not change immediately with respect to a minute or instantaneous acceleration change by increasing the calculation interval of the differentiator 19 or slowing down the response of the low pass filter 20. In particular, the response speed of the acceleration calculated by the acceleration low response processing unit 32 is made slower than the response speed of the acceleration calculated by the acceleration calculating unit 29.

Reference numeral 21 denotes a comparator which compares the magnitude of the acceleration S2 with the acceleration detection level SSET, and when it is determined that the acceleration S2 is greater than the acceleration detection level SSET, the output S3 thereof is at the "H" level (high level), whereas when it is determined that the acceleration S2 is equal to or less than the acceleration detection level SSET, the output S3 thereof is at the "L" level (low level). For example, 1 may be used as the output signal of the "H" level, and 0 may be used as the output signal of the "L" level. The acceleration detection level SSET is a predetermined value set by the electric train, and may be set to be variable. As described later, the comparator 21 functions as an idling detection unit 33.

Reference numerals 22 and 23 denote inverters, which invert the input and output, respectively. Reference numeral 24 is an OFF delay. The output S3 of the comparator 21 is input to the inverter 22, and the inverter 22 outputs S4. The output of the inverter 22, i.e., S4, is input to the multiplier operator 26 and to the inverter 23.

For example, when S3 is at the "H" level, S4 is at the "L" level, S4, which is the value of the "L" level, is input to the multiplier 26, and the value of S4 (hereinafter referred to as gain) is multiplied by the adhesion index ADL 0. The value of the "L" level used for the multiplication by the multiplier 26 is, for example, 0, but is not limited thereto, and may be any value of, for example, 1 or less. Thus, the gain can be set to a value of, for example, 1 or less. When the gain is set to a value of 1 or less, the value obtained by adding the value at the "L" level of S4 and the value at the "H" level of S4 is set to 1. When S4 is 0, the output of the multiplier 26, i.e., the adhesion index ADL, is 0, and therefore the output of the multiplier 27 is also 0. That is, when the acceleration S2 is greater than the acceleration detection level SSET, the idling is controlled by outputting 0 as the torque command T.

On the other hand, when the acceleration S2 is equal to or lower than the acceleration detection level SSET, S3 is at the "L" level, and S4 is at the "H" level, the gain is, for example, 1. Therefore, the adhesion index ADL, which is an output of the multiplier 26, is ADL0, and the torque command T is determined based on the outputs of the first adhesion command generating units 7A to 7D. Thus, inverters 22 and 23 constitute gain generating section 34 based on the output of idle detection section 33. In the present embodiment, the gain is set to switch in accordance with the magnitude relationship between the acceleration S2 and the acceleration detection level SSET. As another mode different from this, the value of the gain may be switched according to the magnitude relationship between the acceleration S2 and, for example, 2 acceleration detection levels. When these 2 acceleration detection levels are set as the first acceleration detection level and the second acceleration detection level smaller than the first acceleration detection level, S2 may be set such that the gain increases in this order for 3 ranges of the first acceleration detection level or more, the second acceleration detection level or more but less than the first acceleration detection level, and less than the second acceleration detection level.

S4 is also input to the inverter 23, and the output of the inverter 23 is input to the open delayer 24. In addition, the output S5 of the off-delay 24 is input to the first-order delay section 28. At this time, when the output S5 of the off delay 24 is once at the "H" level, for example, the "H" level is maintained for a certain period of time, and therefore the "H" level signal continues to be output to the first-order delay unit 28. While S5 is at the "H" level, the time constant τ of the first-order delay unit 28 is switched and set to a predetermined value. In this way, the off-delay 24 functions as the time constant setting unit 35.

Even if the acceleration detection level SSET is set to a value slightly larger than the normal acceleration, S3, which is the output of the comparator 21, remains at the "L" level in the normal idling state where there is no idling state or where the acceleration changes instantaneously. This is because the acceleration low response processing unit 32 delays the response of the acceleration change, and therefore, even if the acceleration of FMmax exceeds the acceleration detection level SSET, S2 remains at the acceleration detection level SSET or less. Since S3 is still at the "L" level, S4 is still at the "H" level, S5 is still at the "L" level, the adhesion index ADL is equal to the adhesion index ADL0, and the time constant τ of the first-order delay section 28 is not switched. Therefore, the control state of the second tackiness index generation unit 8 does not change at all. In this way, in a normal idling state in which acceleration changes instantaneously, the first adhesion index generating units 7A to 7D can perform high-speed and fine optimum adhesion control.

In the event of the idling phenomenon in which the change in acceleration is small and the speed increase is slow, which is caused by the normal acceleration, the first adhesion index generation units 7A to 7D do not perform control to suppress the idling phenomenon, because the speed deviation DFM and the acceleration deviation DFT are small, contrary to the above. On the other hand, when such idling continues, in the second adhesion index generation unit 8, the acceleration S2 becomes equal to or higher than the acceleration detection level SSET, and S4 becomes "L" level, that is, for example, 0, and the adhesion index ADL is always 0 regardless of the calculation results of the first adhesion index generation units 7A to 7D. When the acceleration S2 reaches the acceleration detection level SSET or higher, the acceleration S2 does not instantaneously fall below the acceleration detection level SSET due to the response delay of the acceleration low-response processing unit 32, and this state continues for a while. Since S5 is at the "H" level, the first-order delay unit 28 switches the time constant τ. Then, during a certain period determined by the off delay 24, the torque command T is decreased with a time constant switched with 0 as a target value. Then, when the acceleration S2 is equal to or lower than the acceleration detection level SSET, the torque command T returns to the steady-state torque command based on the adhesion index ADL 0.

Fig. 5 is an operation diagram of the first tackiness index calculation section 7A when the slight idling continues. The horizontal axis represents the operations of FM1 to FM4, FMmin, a1, a2, A3, DFT, DFM, ADL0 when the second tackiness index calculation unit 8 is not functioning. The dashed lines drawn in FM1 to FM4 indicate real speeds, and FM1 to FM4 indicate that the deviation from the real speed increases due to continuous slight idling and idling occurs. It is also found that the acceleration deviation DFT is small, the adhesion index ADL0 changes only slightly from 1, and no control is performed to suppress idling.

Fig. 6 is an operation diagram of FM1 to FM4, FMmax, ADL0, S1, S2, ADL, T0, and T when the second tackiness index calculation unit 8 functions. FM1 to FM4 show a mode in which the deviation from the true speed gradually increases with time due to the continuous slight idling, but the deviation again decreases, and the idling is suppressed by the control of the second adhesion index calculation unit 8. Since S1 is subjected to the first-order delay by the low-pass filter 20, S2 exceeds the acceleration detection level SSET during time t2 to t5, and the value of ADL becomes 0. In the range from time T2 to T3, the value of T decreases from approximately 1 to 0, but the rate of change is determined by setting the time constant τ of the first order delay unit 28.

As described above, according to the present embodiment, the acceleration deviation DFT and the speed deviation DFM are small, and even when the idling is difficult to be suppressed in the control by the first adhesion index generating units 7A to 7D, the idling can be suppressed by the second adhesion index generating unit 8. Therefore, it is possible to grasp the idling phenomenon only from the speed information of the drive shaft without adding new shaft speed information such as a non-drive shaft, and to detect the idling state before the speed is greatly different from the actual value, and to perform appropriate idling control. According to the present embodiment, particularly during high-speed running or the like, idling can be detected and suppressed.

The configuration shown in the above embodiment is an example of the content of the present invention, and may be combined with a known technique or the like, and it goes without saying that the configuration is modified within a range not departing from the gist of the present invention.

The application field of the idle control according to the present invention is not limited to the control device of the electric train, and may be applied to the related field such as the electric vehicle.

Industrial applicability of the invention

As described above, the control device for an electric train according to the present invention is useful for suppressing the occurrence of idling/coasting during high-speed travel on a high-speed railway or the like.

Claims (8)

1. A control device for an electric vehicle, comprising a plurality of motors and an idle-run coasting control unit that generates a torque command value based on the rotational speeds of the plurality of motors to suppress idling or coasting, characterized in that,

the idle slide control unit includes:

a first adhesion index generation unit that generates a first adhesion index serving as an index for suppressing a first slip or a first slip based on an acceleration deviation and a speed deviation obtained from the rotation speed;

a second adhesion index generation unit that generates a second adhesion index serving as an index for suppressing a second idling or a second coasting, the acceleration deviation or the speed deviation of which is smaller than that of the first idling or the first coasting, based on the first adhesion index and an acceleration obtained from the rotation speed; and

a torque command value generation unit that generates the torque command value based on the second adhesion index.

2. A control device for an electric vehicle, comprising a plurality of motors and an idle-run coasting control unit that generates a torque command value based on the rotational speeds of the plurality of motors to suppress idling or coasting, characterized in that,

the idle slide control unit includes:

a reference rotation speed calculation unit that calculates a first reference rotation speed and a second reference rotation speed from rotation speeds of the plurality of motors;

a first adhesion index generation unit that receives the first reference rotation speed, and generates a first adhesion index that is an index of adhesion between a wheel and a tread surface coupled to each of the motors, based on an acceleration deviation generated based on an acceleration calculated from a rotation speed of each of the motors and a speed deviation generated based on a rotation speed of each of the motors;

a second tackiness index generation unit that generates a second tackiness index value based on an acceleration calculated from the second reference rotation speed, the second tackiness index value being generated based on a gain generated based on the acceleration and the first tackiness index value, the second tackiness index value being input from the second reference rotation speed; and

a torque command value generation unit that generates the torque command value based on the second adhesion index value.

3. A control device for an electric vehicle, comprising a plurality of motors and an idle-run coasting control unit that generates a torque command value based on the rotational speeds of the plurality of motors to suppress idling or coasting, characterized in that,

the idle slide control unit includes:

a reference rotation speed calculation unit that calculates a first reference rotation speed and a second reference rotation speed from rotation speeds of the plurality of motors;

a first adhesion index generating unit that is provided in association with each of the motors, and generates a first adhesion index that is an index of adhesion between a wheel and a tread surface of the wheel coupled to each of the motors, based on an acceleration deviation that is a difference between an acceleration calculated from a rotational speed of each of the motors and an acceleration calculated from the first reference rotational speed, and a speed deviation that is a difference between a rotational speed of each of the motors and the first reference rotational speed, with the first reference rotational speed and the rotational speed of each of the motors as inputs;

a second adhesion index generation unit that generates, as a second adhesion index value, a value obtained by multiplying the first adhesion index value by a gain generated based on an acceleration calculated from the second reference rotation speed, with the second reference rotation speed as an input; and

a torque command value generation unit that generates the torque command value based on the second adhesion index value.

4. The control device for electric vehicles according to claim 3,

the idle running slide control unit further includes an adhesion index processing unit that calculates an individual adhesion index from the plurality of first adhesion indexes generated by the plurality of first adhesion index generation units, and outputs the individual adhesion index as a first adhesion index to the second adhesion index generation unit,

the torques of the plurality of motors are collectively controlled based on a second adhesion index value that is a value obtained by multiplying the gain generated by the second adhesion index generation unit by the individual adhesion index.

5. The control apparatus for electric train according to claim 3 or 4,

the first tackiness index generation section includes a first acceleration calculation section that calculates an acceleration from the rotational speed of each motor and calculates an acceleration from the first reference rotational speed,

the second tackiness index generation section includes a second acceleration calculation section that calculates an acceleration from the second reference rotation speed,

the response speed of the acceleration calculated by the second acceleration calculation unit is made slower than the response speed of the acceleration calculated by the first acceleration calculation unit.

6. The control apparatus for electric train according to claim 3 or 4,

the second adhesion index generation unit switches the value of the gain according to whether or not the acceleration calculated from the second reference rotation speed is greater than a predetermined set value, and sets the value of the gain to be smaller when the acceleration is greater than the predetermined set value.

7. The control apparatus for electric train according to claim 3 or 4,

the second adhesion index generation unit switches the gain value between the first set value and the second set value smaller than the first set value, and sets the gain value to increase in this order for 3 ranges of the first set value or more, the second set value or more and less than the first set value, and less than the second set value, the acceleration calculated from the second reference rotation speed.

8. The control apparatus for electric train according to claim 3 or 4,

the torque command value generation unit includes a first-order delay unit that outputs the torque command value generated based on the second tackiness index value with a first-order delay,

the second tackiness index generation section includes a disconnection delayer that sets a time constant of the first-order delay section in correspondence with a value of the gain.