JP2588245B2 - Cooling device for vehicle electric motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a vehicular motor cooling device that cools a vehicular motor by introducing cooling air from an electric blower.

(Prior Art) In general, in order to cool an electric motor that drives a vehicle, an electric blower connected to the electric motor via a wind guide is driven to introduce cooling air into the electric motor.

FIG. 4 shows a circuit configuration of a cooling device when four motors are used for one vehicle as an example. In FIG. 4, the electric motors 20, 21 are mounted on the same bogie,
It is connected and connected to one electric blower 24 by a wind guide 26 branched into two. The electric blower 24 is connected to a power supply 28, and is operated at a constant rotation speed by inputting power maintained at a substantially constant frequency-constant voltage by the power supply 28. The electric motors 22 and 23 are mounted on the other bogie, and are connected to and connected to one electric blower 25 through a two-branch air guide 27. The electric blower 25 is also the same as the electric blower 24 described above. The power supply 28 is operated at a constant rotation speed.

Therefore, in the cooling device having such a configuration, to cool the electric motors 20, 21, 22, and 23, the electric
Since electric power having a substantially constant frequency and a constant voltage is supplied to the electric blowers 4 and 25, the electric blowers 24 and 25 are operated at a constant rotation speed, and a substantially constant amount of cooling air is always supplied through the wind guides 26 and 27, respectively. Will be introduced to the motor.

By the way, in a vehicle that generates a large traction force such as a locomotive, a remarkable axle load movement phenomenon occurs.

Here, the axial load movement phenomenon and its problems will be described with reference to FIG. The axle load may be generated between wheels of the front and rear bogies or may be generated between wheels in the same bogie.

In the case of a general bogie, the axle load on each wheel can be expressed by the following equation.

First axis ΔW1 = −4F (H−h) / 2L × 2Fh / 2l = −F (H−h) / L−Fh / l (1) Second axis ΔW2 = −4F (H−h) / 2L × 2 + 2FH / 2l = F (H−h) / L + Fh / l (2) Third axis ΔW3 = 4F (H−h) / 2L × 2-2FH / 2l = F (H−h) / L− Fh / l (3) Fourth axis ΔW4 = 4F (H−h) / 2L × 2 + 2Fh / 2l = F (H−h) / L + Fh / l (4) where ΔW1: Axle load of wheel 29a , ΔW2: axle load of wheel 29b, Δ
W3: Axle load of wheel 29c, ΔW4: Axle load of wheel 29d, 21: Distance between wheels in the same bogie, 2L: Distance between core shafts 30 and 31, F: Traction force, H: Center height of coupler, h : Transmission point height In the case of an ordinary bogie whose axle weight is not corrected, as described above, there are axle weight movement between wheels in the same bogie and axle weight movement between wheels of front and rear bogies.

From the above equations (1) to (4), the axle weight of each wheel is the lightest for the first axle wheel 29a, and the third axle wheel 29c, the second axle wheel 29b, and the fourth axle wheel 29d in this order. Heavier.

If the output of each motor is operated under the same conditions, the frictional force between the tread and the rail of the wheel with the lighter axle weight is smaller than that of the wheel with the heavier axle load, making it easier for the wheels to spin. There is a danger that a given motor will run at high speed. Therefore, in order to solve such a problem, axle load correction is mechanically performed, or axle load compensation is performed by electrical control.

First, in the case of an axle load movement prevention bogie that has been subjected to axle load correction, the axle weight of the wheels of the entire bogie in front of the traveling direction is light, and conversely, the axle weight of the wheels of the entire bogie behind the traveling direction is heavy, and Axial load movement between the wheels is small.

Therefore, when all the electric motors are operated at the same rating, the wheels of the bogie in front of the traveling direction are more likely to idle.

Next, as a means for solving this problem, there is an axial load compensation by electrical control. As a method of compensating for the axle load by the electric control, there is a method of preventing idling of the wheels by starting the electric motor in a weak magnetic field to reduce the generated torque. However, this method has a disadvantage that the total traction force is reduced. In addition, in order to prevent slipping without lowering the traction force, it is only necessary to control each motor individually, but in this case, the output of the motor driving the shaft with the heavier axle load becomes excessive, so that it is inevitable. In addition, the temperature rise of the motor is increased, and the insulation of the motor is deteriorated and the life is shortened. Further, a motor whose capacity is increased in advance in proportion to the increase in axle load may be used, but this causes a new problem that the weight of the motor necessarily increases.

(Problems to be Solved by the Invention) As described above, in a general bogie, in order to prevent axle weight movement occurring between wheels in the same bogie and between wheels of front and rear bogies, axle weight correction is mechanically performed. Axle load compensation is performed by electrical control, but in this case, if all the motors are operated at the same rating, the wheel with the lighter axle load spins. Therefore, as means for preventing the wheels from spinning without lowering the traction force, it is only necessary to control each motor individually, but the output of the motor driving the shaft with the heavier axle becomes excessively large. As a result, the temperature rise of the electric motor increases.

However, the conventional cooling device for a motor for a vehicle operates the electric blowers 24 and 25 at a constant rotation speed with electric power of a constant frequency and a constant voltage supplied from the electric wire 28, so that the one having a heavier axle load is used. There is a problem that the temperature rise of the motor driving the shaft cannot be suppressed, and eventually the capacity of the motor must be increased.

The present invention can control each motor individually to compensate for axle load movement, and can effectively suppress a rise in temperature of the motor even if the output of the motor driving a wheel with heavy axle load is increased. An object of the present invention is to provide a cooling device for a motor for a vehicle.

[Means for Solving the Problems] In order to achieve the above object, the present invention performs axle load correction on axle load movement generated between wheels in the same bogie,
In addition, a plurality of vehicle motors in which driving force control according to the axle load is performed with respect to the axle load movement generated between the wheels of the bogie before and after the traveling direction of the vehicle, respectively correspond to each vehicular motor or each bogie. And a variable voltage variable frequency inverter, which is provided and connected by wind conduction for introducing cooling air to each of the vehicle electric motors, and receives a power output and supplies power of the variable voltage variable frequency to each of the electric blowers. When the forward / reverse switching signal is output from the master controller, the cooling air volume increases with respect to the motor for a vehicle that drives wheels with a large axle load or the electric blower corresponding to the bogie with a large axle load specified from the traveling direction of the vehicle. And a corresponding inverter control device for controlling the corresponding variable voltage variable frequency inverter.

(Operation) Accordingly, in the vehicle electric motor cooling device having such a configuration, when, for example, a power running forward signal is output from the master controller to the inverter control device, the inverter control device is moved rearward in the vehicle traveling direction. A high frequency signal is given to a variable voltage variable frequency inverter of an electric blower provided corresponding to a truck or a motor driving wheels mounted on the truck, and the variable voltage variable frequency inverter supplies another electric blower to the electric blower. Power is supplied at a higher frequency, so that the amount of cooling air introduced into the motor that drives wheels mounted on a step behind the electric blower in the vehicle traveling direction increases, driving wheels with heavy axle load. Even if the output of the electric motor is increased, the temperature rise of the electric motor can be effectively suppressed.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention.
Here, the traveling direction of the vehicle is set to the direction shown in FIG. 5, and four motors are mounted on a bogie.
In FIG. 1, reference numerals 20 and 21 denote electric motors mounted on the front of the bogie in the vehicle traveling direction to drive wheels 29a and 29b in FIG.
Is mounted rearward in the vehicle traveling direction of the bogie, and the wheels 29 in FIG.
These electric motors drive c and 29d, and these electric motors 20 to 23 are connected to the electric blowers 1 to 4 by the air guides 5 to 8 so as to communicate with each other. Reference numerals 9 to 12 denote variable voltage variable frequency inverters (hereinafter referred to as VVVF inverters) provided corresponding to the electric blowers 1 to 4, respectively.
The VF inverters 9 to 12 receive the output from the power supply 28 and supply electric power of variable voltage and variable frequency to the corresponding electric blowers 1 to 4 to operate. On the other hand, 13 is a main controller for outputting a forward / reverse switching signal, 14 is an inverter control circuit to which a forward / reverse switching signal is input from the main controller 13, and the inverter control circuit 14 is, for example, a forward power running from the main controller 13. When a signal is input, a frequency signal is given to the electric blowers 9, 10 of the electric motors 20, 21 mounted in front of the bogie in the vehicle traveling direction to operate at a steady frequency, and it is specified that the axle load becomes heavy. A high frequency signal is supplied to the electric blowers 11 and 12 of the electric motors 22 and 23 mounted on the rear of the bogie in the vehicle traveling direction to control the VVVF inverters 9 to 12 in order to operate at a high frequency. is there.

Next, the operation of the first embodiment configured as described above will be described.

Now, when the powering forward signal is input from the master controller 13 to the inverter control circuit 14, the inverter control circuit 14 corresponds to the electric blowers 1, 2 of the motors 20, 21 mounted forward in the vehicle traveling direction of the bogie. To the VVVF inverters 9 and 10 to operate at a steady frequency, and the electric blowers 3 and 4 of the motors 22 and 23 mounted on the rear of the bogie in the vehicle traveling direction specified when the axle load becomes heavy. Are supplied to the VVVF inverters 11 and 12 corresponding to the high frequency operation in order to operate at a high frequency. Then, each of these VVVF inverters outputs electric power of the frequency corresponding to the respective frequency signal to the electric blowers 1 to
4 Therefore, the electric blowers 1 and 2 are operated at a steady rotation speed, and the cooling air obtained therefrom is sent into the electric motors 20 and 21 through the air guides 5 and 6, so that these electric motors 20 and 21 are cooled by the cooling air. Is done. In addition, since the electric blowers 3 and 4 are operated at a high rotation speed, cooling air having a larger air volume than the steady state obtained from the electric blowers
Through the motors 22 and 23,
2 and 23 are cooled by cooling air having a larger air volume than the steady state. This makes it possible to suppress an increase in the temperature of the electric motors even when the outputs of the electric motors 22 and 23 that drive the wheels with heavy axle load are increased by the powering advance signal from the master controller 13.

Here, when examining and examining the relationship between the motor temperature and the motor current, the motor temperature and the cooling air flow rate, and the relationship between the cooling air flow rate and the rotation speed of the electric blower, the following relational expressions are generally established scientifically.

T = K ₁ I ² …… (5) T = K ₂ Q ^−0.4 …… (6) Q = N …… (7) where T: temperature, K ₁ , K ₂ : constant, I: current, Q : Cooling air volume, N:
It is the rotation speed of the electric blower.

From the above equations (6) and (7), the relationship between temperature, current and cooling wind is as follows.

T = K ₃ · I ² × Q ^-0.4 (8) Further, from the equation (8), the relation between the current and the cooling air volume when the temperature T is constant is given by the following equation.

I = K ₄ · Q ^0.2 (9) In addition, an induction motor is used as a motor of the electric blower, and its rotation speed is proportional to a power supply frequency represented by the following equation.

N = 120f / P ...... (10 ) N = k 5 f ...... (11) where, N: rotational speed, f: Frequency, P: the number of poles.

From the above equations (7), (8) and (11), I = K ₆ f ^0.2 ... (12) From each of the above equations, if the motor output of the truck behind the traveling direction is increased by, for example, + 10%, The temperature of the electric motor rises by about 20%. In this case, it is sufficient to operate the electric blower at about 60%. At this time, the frequency of the VVVF inverter may be about + 60%.

Therefore, although the forward / reverse switching signal from the master controller is the powering forward signal, the VV corresponding to the electric blower of the motor that drives the wheel with heavy axle load depends on whether it is the powering backward signal.
By simply setting the VF inverter in advance, by controlling the VVVF inverter based on data obtained from the relationship between the rotation speed of the electric blower determined by the increase in the motor temperature with respect to the increase in the output of the motor and the frequency of the VVVF inverter at that time, Even if the output of the motor is increased, a rise in the temperature of the motor can be suppressed, so that it is possible to individually control the motors that drive the wheels to compensate for the axle load movement.

FIG. 2 shows a second embodiment of the present invention. In FIG. 2, the same parts as those in FIG. 1 are denoted by the same reference numerals, and their description will be omitted. Only different points will be described here. That is, in the first embodiment, a transmission blower and a VVVF inverter are provided for each of the electric motors 20 to 23. However, in the second embodiment, as shown in FIG. Electric blowers 24 and 25 and VVVF inverters 15 and 16 are provided, and cooling air is introduced into the electric motors 20 and 21 through the air guide 26 branched from the electric blower 24. The electric blowers are supplied to the electric motors 22 and 23. The cooling air is introduced through an air guide 27 branched into two from the cooling air 25.

Accordingly, in such a configuration, when a powering advance signal is output from the master controller 13, the inverter control circuit 14 outputs a normal frequency signal to the VVVF inverter 15 and a high frequency signal to the VVVF inverter 16 in the same manner as in the previous embodiment. And the cooling air is sent from the electric blowers 24 and 25 to the electric motors 20 to 23, respectively, so that the cooling capacity of the electric motors 22 and 23 mounted on the bogie on the rear side in the traveling direction of the vehicle can be improved.

FIG. 3 shows a third embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. Only different points from FIG. 1 will be described here. That is, in the third embodiment, as shown in FIG.
Temperature detectors 17a to 17d are provided for 23, and a temperature detection signal of the electric motor detected by each of the temperature detectors 17a to 17d is input to the inverter control circuit 14 and the VVVF inverters 9 to 12 are provided.
Is controlled. In this case, the inverter control circuit 14 gives a high-frequency signal to the VVVF inverter corresponding to the electric blower of the electric motor that drives the wheel with heavy axle weight by the forward / reverse switching signal output from the master controller 13,
Further, when the temperature detection signal exceeds a certain value, a higher high frequency signal is given to the VVVF inverter.

Therefore, in such a configuration, when the temperature of the electric motor 23 rises and exceeds a certain value, the temperature detector corresponding to the electric motor 23
Since a temperature detection signal is input from 17d to the inverter control circuit 14, the inverter control circuit 14 sends a high frequency signal to the VVVF inverter 12. As a result, the electric blower 4 is operated at a high rotation speed, and more cooling air is sent to the electric motor 23 through the wind guide 8.
Can be improved.

[Effects of the Invention] As described above, according to the present invention, even if the output of a motor that drives wheels with heavy axle load is increased while controlling each motor individually to compensate for axle load movement, A cooling device for a motor for a vehicle that can effectively suppress a rise in the temperature of the motor can be provided.

[Brief description of the drawings]

FIGS. 1 to 3 are circuit diagrams showing first to third embodiments of a cooling device for a motor for a vehicle according to the present invention, respectively.
FIG. 4 is a circuit diagram showing an example of a conventional cooling device for a motor for a vehicle, and FIG. 1-4,25,25 …… Electric blower, 5-8,26,27 …… Wind guide, 9
... 12,15,16 ... VVVF inverter, 17a-17d ... Temperature detector, 13 ... Master controller, 14 ... Inverter control circuit, 20
~ 23 ... Electric motor, 28 ... Power supply.

Claims (1)

(57) [Claims] An axle load is corrected for axle weight movement occurring between wheels in the same bogie, and axle load is reduced for axle weight movement occurring between wheels of a bogie in front and rear directions of the vehicle. In a plurality of vehicle electric motors for which a corresponding driving force control is performed, an electric blower provided corresponding to each vehicle electric motor or each truck and connected by wind conduction for introducing cooling air to each vehicle electric motor. A variable voltage variable frequency inverter that receives power supply output and supplies a variable voltage variable frequency power to each electric blower, and an axle load specified from the traveling direction of the vehicle when a forward / reverse switching signal is output from the master controller. An inverter for controlling the variable voltage variable frequency inverter corresponding to an electric motor for a vehicle driving a large wheel or an electric blower corresponding to a bogie having a large axle load so as to increase the amount of cooling air. Cooling device for a vehicle electric motor, characterized by comprising a control device.