JPWO2019159249A1 - Electric motor monitoring device, electric motor control system, steel rolling system and electric motor monitoring method - Google Patents

Abstract

To enable accurate detection of the state of the motor at low cost. For that purpose, a plurality of electric motors each having a rotating shaft, a plurality of rotating wheels each coupled to the plurality of rotating shafts, one or a plurality of electric motors for supplying AC current to the plurality of electric motors, and a control for controlling the inverters. It is connected to a motor control system equipped with a unit and a current sensor that detects the current values (Iu1, Iu2, Iw1, Iw2) flowing through each motor, and responds to each current value (Iu1, Iu2, Iw1, Iw2). Then, based on the calculation unit (42-1, 42-2) that calculates the rotation speed (ωrs1, ωrs2) of the corresponding electric motor, and the current value and the rotation speed, the overheated state of any of the motors, or a plurality of motors. It is provided with a determination unit (44, 48) for detecting at least one of the abnormalities in the diameter difference of the rotating wheels.

Description

The present invention relates to an electric motor monitoring device, an electric motor control system, a steel rolling system, and an electric motor monitoring method.

A technique for monitoring the state of these electric motors while driving a plurality of electric motors in parallel is known.
For example, the following Patent Document 1 states, "A motor overtemperature protection device applicable to a railway vehicle drive system in which a plurality of electric motors are operated in parallel by using one or a plurality of inverter devices, wherein the inverter device 10 The control device 14 for controlling the operation of the motor, the frequency signal fs including the frequency information when the inverter device 10 controls the electric motors 12a and 12b to keep the ratio of the voltage and the frequency constant, and the electric motors 12a and 12b. Based on the currents I1 and I2 of at least one flowing phase, the overtemperature that can occur in the electric motors 12a and 12b is detected, and the overtemperature protection signal Tf for protecting the electric motors 12a and 12b from the overtemperature is generated and controlled. It includes a protective device 20 that outputs to the device 14 ”(see abstract).
Further, in Patent Document 2 below, "... the wheels connected to the first induction motor group by comparing the electric currents of the first and second induction motor groups and detecting the difference between them. The electric vehicle protection method is characterized by detecting the difference between the diameter of the motor and the diameter of the wheel connected to the second induction motor group and protecting the difference when the difference is equal to or greater than the permissible value. " (See the left column on page 1).

International Publication No. 2013/0351885 JP-A-61-21801

However, since the technique of Patent Document 1 focuses on the relative current difference between a plurality of electric motors, there is a problem that it becomes difficult to detect when these electric motors are in an overheated state at the same time. In addition, it was difficult to distinguish whether the cause of the temperature rise was due to the difference in the installation environment of each motor or the difference in the diameter of the rotating wheels. Further, in the technique of Patent Document 2, it is difficult to determine whether the current difference generated in the plurality of electric motors is due to the wheel diameter difference or other factors.
Further, in the technique of Patent Document 2, since it is necessary to attach a sensor such as a temperature sensor or a speed sensor to each monitoring target, there is a problem that the number of related devices including the sensor increases and the cost of the entire facility increases. In addition, there is a problem that it is difficult to install the sensor when there are dimensional restrictions on the installation location of the electric motor or in harsh environmental conditions. Further, as the number of sensors increases, it becomes difficult to secure the reliability of the sensor group, and there is also a problem that the monitoring accuracy decreases. Therefore, there is a demand to reduce the number of sensors to be applied as much as possible.

If the number of sensors can be reduced, maintainability and reliability will be greatly improved. Specifically, the maintenance and inspection work of the sensor can be reduced, the system down due to the sensor failure can be prevented, the equipment wiring of the sensor system can be reduced, the work cost can be reduced, and wiring troubles can be caused. Concerns can be reduced.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric motor monitoring device, an electric motor control system, a steel rolling system, and an electric motor monitoring method capable of accurately detecting the state of an electric motor at low cost.

In order to solve the above problems, the electric motor monitoring device of the present invention supplies an AC current to a plurality of electric motors each having a rotating shaft, a plurality of rotating wheels coupled to the plurality of rotating shafts, and a plurality of the electric motors. It is connected to an electric motor control system including one or a plurality of motors, a control unit for controlling the motors, and a current sensor for detecting the current value flowing through each of the electric motors, and according to each of the electric motors. At least one of the overheated state of any of the electric motors or the abnormality of the diameter difference of the plurality of rotating wheels based on the calculation unit for calculating the rotational speed of the corresponding electric motor and the current value and the rotational speed. It is characterized by including a determination unit for detecting the above.

According to the present invention, the state of the electric motor can be accurately detected.

It is a block diagram of the electric motor control system according to 1st Embodiment of this invention. It is a block diagram of a monitoring device. It is a block diagram of a current calculation part. It is a figure which shows the example of the mechanical frequency and the amount of DC during acceleration. It is a figure which shows another example of the DC amount during acceleration. It is a figure which shows still another example of a DC amount and a proportional signal during acceleration. It is a figure which shows the determination result of the abnormality content based on the current difference between a low speed region and a high speed region. It is a flowchart of an abnormality detection routine executed in a monitoring device. It is a block diagram of the electric motor control system according to 2nd Embodiment. It is a block diagram of the electric motor control system according to 3rd Embodiment. It is a block diagram of the electric motor control system according to 4th Embodiment. It is a block diagram of the steel rolling system according to 5th Embodiment. It is a side view of the railroad vehicle according to the sixth embodiment. It is a bottom view of the dolly in the sixth embodiment. It is a side view of the vehicle formation by 7th Embodiment.

[First Embodiment]
<Overall configuration of the first embodiment>
FIG. 1 is a block diagram of the electric motor control system 101 according to the first embodiment of the present invention.
In FIG. 1, the electric motor control system 101 includes two electric motors 10-1 and 10-2, a drive device 20, a monitoring device 40 (electric motor monitoring device), and a plurality of current sensors 41. The drive device 20 includes an inverter 22, a current sensor 24, and a control unit 30. Here, the electric motors 10-1 and 10-2 are three-phase induction motors and are connected to each other in parallel. The rotating shafts 14-1 and 14-2 of the electric motors 10-1 and 10-2 are connected to the rotating wheels 16-1 and 16-2 via mechanical parts such as gears (not shown) or directly connected to each other. Has been done. The rotating wheels 16-1 and 16-2 move the conveyed object 12 in the tangential direction. Alternatively, a rail for railroad may be provided instead of the transported object 12, and the rotating wheels 16-1 and 16-2 themselves may move in the tangential direction on the rail. Hereinafter, the electric motors 10-1 and 10-2 are collectively referred to as "electric motor 10", the rotating shafts 14-1 and 14-2 are collectively referred to as "rotating shaft 14", and the rotating wheels 16-1 and 16-2 are collectively referred to as "rotating wheel 16". Sometimes. The inverter 22 applies a three-phase AC voltage to the electric motor 10 based on the control of the control unit 30.

The control unit 30 is equipped with general computer hardware such as a CPU (Central Processing Unit), a DSP (Digital Signal Processor), a RAM (Random Access Memory), and a ROM (Read Only Memory). , A control program executed by the CPU, a microprogram executed by the DSP, various data, and the like are stored. In FIG. 1, the inside of the control unit 30 shows the functions realized by the control program, the microprocessor, and the like as blocks.

That is, the control unit 30 includes a command generation unit 32, a deviation calculation unit 33, a vector control unit 34, a dq / 3Φ conversion unit 36, and a 3Φ / dq conversion unit 38. With these configurations, the control unit 30 performs vector control on the electric motor 10 to improve the responsiveness of the electric motor 10.

The inverter 22 outputs U-phase, V-phase, and W-phase alternating current to the electric motor 10. The current sensor 24 detects the two-phase currents. That is, in the illustrated example, the U-phase and W-phase currents are detected, and the results are output as current detection values I _us and I _ws . Here, assuming a rotating coordinate that rotates at a frequency f, the axes orthogonal to the rotating coordinate are called the d-axis and the q-axis, and the current supplied to the electric motor 10 is expressed as a DC amount in the rotating coordinate. The current on the q-axis is a current component that determines the torque of the electric motor 10, and is hereinafter referred to as torque current. Further, the current on the d-axis is a component that becomes the exciting current of the electric motor 10, and hereinafter, this is referred to as an exciting current.

The 3Φ / dq conversion unit 38 outputs the exciting current detection value I _d and the torque current detection value I _q based on the current detection values I _us and I _ws . By the way, the current detection values I _us and I _ws tend to increase in proportion to the number of electric motors 10. However, since it is complicated to change the parameters of the control unit 30 according to the number of electric motors 10, the control unit 30 assumes that the number of electric motors 10 is "1". Therefore, the 3Φ / dq conversion unit 38 divides the supplied current detection values I _us and I _ws by the number of the electric motors 10 to normalize them, and then calculates the detection values I _d and I _q .

The command generation unit 32 receives the torque command value τ * from a higher-level device (not shown), and generates the exciting current command value I _d * and the torque current command value I _q * based on the torque command τ *. To do. Deviation calculation unit 33, * current command value I _d, and I _q *, the detection value I _d, based on the I _q, deviation I _d * -I _d, and outputs the I _q * -I _q. Vector control unit 34 on the basis the deviation I _d * -I _d, the I _q * -I _q like, and the excitation voltage command value V _d *, and outputs the torque voltage command value V _q *. In more detail the operation of the vector control unit 34, the vector control unit 34, the deviation I _d * -I _d, performs proportional-integral control with respect to I _q * -I _q, which is a command value of the synchronous speed frequency Obtain command ω1 (not shown). The synchronous speed is the rotation speed of the electric motor 10 assuming that the slip is “0”.

Further, the vector control unit 34 obtains the phase command θ1 (not shown) by integrating the frequency command ω1. Further, the vector control unit 34 multiplies the vector formed by the current command values I _d * and I _q * by the impedance vector of the electric motor 10, and as a result, obtains the voltage command values V _d * and V _q *. calculate.

The dq / 3Φ conversion unit 36 outputs a PWM signal for driving the inverter 22 based on the voltage command values V _d * and V _q * of the rotating coordinate system. More specifically, the dq / 3Φ conversion unit 36 first sets the voltage command values V _d * and V _q * of the rotating coordinate system based on the frequency command ω1 and the phase command θ1 of the stationary coordinate system. Convert to a two-phase voltage value. Further, the dq / 3Φ conversion unit 36 converts the obtained two-phase voltage value into three-phase voltage command values v _u *, v _v *, v _w * (not shown). Further, the dq / 3Φ conversion unit 36 compares the three-phase voltage command values v _u *, v _v *, v _w * with the carrier wave (for example, a triangular wave) to obtain U-phase, V-phase, and W-phase. Outputs a PWM signal. The inverter 22 switches the supplied DC voltage (not shown) based on the supplied PWM signal, and outputs U-phase, V-phase, and W-phase voltages to the electric motor 10.

<Configuration of monitoring device 40>
FIG. 2 is a block diagram of the monitoring device 40.
Similar to the control unit 30 described above, the monitoring device 40 includes hardware as a general computer such as a CPU, DSP, RAM, and ROM, and the ROM includes a control program executed by the CPU and a DSP. The microprogram to be executed and various data are stored. In FIG. 2, the inside of the monitoring device 40 shows the functions realized by the control program, the microprocessor, and the like as blocks.
That is, the monitoring device 40 includes the current calculation units 42-1 and 42-2 (calculation unit), the feature amount extraction unit 44 (determination unit), the storage unit 46, and the abnormality determination unit 48 (determination unit, abnormality determination process). ) And.

The current calculation units 42-1 and 42-2 (hereinafter, both may be collectively referred to as the current calculation unit 42) have U-phase current detection values I _u1 and I _u2 (the same, the same, respectively) from the corresponding current sensors 41. The current detection values I _u (current value) and the W phase current detection values I _w1 and I _w2 (same, current detection value I _w , current value) are acquired. The current calculation unit 42, based on these detected values, a DC quantity I _r1, I _r2 (same DC volume I _r) proportional signal PLL_P1, PLL_P2 (up, proportional signal PLL_P), mechanical frequency omega _rs1 , Ω _rs2 (same as above, mechanical frequency ω _rs , rotation speed), and are output.

Here, with reference to FIG. 3, the significance of the signals output from the current calculation unit 42 will be described. Note that FIG. 3 is a block diagram of the current calculation unit 42.
The current calculation unit 42 includes a 3Φ / αβ converter 52, an inverse tangent converter 54 (phase detection unit), a subtractor 56 (PLL calculation unit), and a phase calculation unit 60 (PL calculation unit, rotation speed calculation unit, It includes a rotation speed calculation process), a rotation coordinate converter 70, an integrator 72 (PLL calculation unit), and a multiplier 74. Further, the phase calculator 60 includes multipliers 62 and 64, an integrator 66, and an adder 68.

The 3Φ / αβ converter 52 converts the current detection values I _u and I _w into orthogonal two-phase alternating currents I _α and I _β . The inverse tangent converter 54 calculates the AC current phase angle detection value θ _i * based on these AC currents I _α and I _β . The subtractor 56 subtracts the AC current phase angle detection value θ _i * from the AC current phase angle θ _i (details will be described later).

In the phase calculator 60, the multiplier 62 multiplies the difference value “θ _i * −θ _i ” by a predetermined proportional gain KpPLL. The multiplication result in the multiplier 62 is the proportional signal PLL_P described above. Further, the multiplier 64 multiplies the difference value “θ _i * −θ _i ” by a predetermined integration gain KiPLL, and the integrator 66 integrates the multiplication result. The integration result in the integrator 66 is called an integration signal PLL_I. The adder 68 adds the proportional signal PLL_P and the integral signal PLL_I, and outputs the addition result as the frequency signal ω _1s .

The integrator 72 integrates the frequency signal ω _1s and outputs an alternating current phase angle θ _i . The AC current phase angle θ _i is supplied to the subtractor 56 and also to the rotating coordinate converter 70. Further, the multiplier 74 multiplies the frequency signal ω _{1 s} by "2 / P" (where P is the number of poles of the electric motor 10), and outputs the multiplication result as the mechanical frequency ω _rs . Here, the mechanical frequency ω _rs is a signal corresponding to the actual speed (speed including slip) of the electric motor 10 (see FIG. 1). Rotating coordinate converter 70 converts alternating current I _alpha biphasic the I _beta, DC amount of biaxial in a rotating coordinate system that rotates at the frequency signal omega _1s I _r, the I _i.

In this way, the subtractor 56, the phase calculator 60, and the integrator 72 function as a PLL (Phase Locked Loop) calculation unit, and the difference value “θ _i * −θ _i ” output by the subtractor 56 is “0”. Outputs a frequency signal ω _1s and an AC current phase angle θ _i that approaches.

Returning to Figure 2, the feature extraction unit 44 includes a DC quantity I _r1, I _r2 is a direct current amount I _r, each corresponding to the motor 10-1 and 10-2, proportional signal PLL_P1, and PLL_P2, mechanical frequency omega _rs1 , Ω _rs2, and multiple values called features are extracted. Here, the details of each of the feature quantities will be described later, but the "feature quantity" includes the low-speed region current difference _IL , the low-speed region proportional signal difference H _L1 , H _L2 , the high-speed region current difference I _H , and the correction high speed. The regional current difference _IQ (high-speed regional current difference) is included.

Based on these feature quantities, the abnormality determination unit 48 determines the presence or absence of an overheated state of the electric motors 10-1 and 10-2 and the diameter difference between the rotating wheels 16-1 and 16-2 (hereinafter referred to as a rotating wheel diameter difference). To detect. Further, the abnormality determination unit 48 outputs various alarm signals to the outside based on these feature quantities. In addition, the storage unit 46 stores the features and the contents of the alarm signal. The alarm signal may be any means that can notify the administrator, such as lighting a lamp, sounding an alarm, or transmitting radio waves by wireless communication means. When the monitoring device 40 in the present embodiment is installed in a harsh environment, it is preferable to store the monitoring device 40 in a monitoring device case provided with dustproof and waterproof measures. Further, when the monitoring device 40 is installed near a device that generates noise such as an inverter 22, it is preferable to take noise countermeasures on the monitoring device 40.

As described above, since the monitoring device 40 can handle the current flowing through the electric motor 10 as a DC amount, it becomes easy to detect a change in the internal state amount of the electric motor 10 including a transient phenomenon. Further, since the speed information in the variable speed drive can be detected in the process of converting the AC amount into the DC amount, the correlation with the rotation speed can be easily analyzed. Further, since the conversion from alternating current to direct current is possible by a simple algorithm, edge processing for determining an abnormality can also be executed in the monitoring device. As a result, the amount of data can be significantly reduced and the analysis / diagnosis work becomes easy.

<Abnormal state to be detected>
(Overheating of electric motor)
In FIG. 1, the motor resistance values and the like of the motors 10-1 and 10-2 vary depending on the operating temperature. Here, a certain temperature (for example, 20 ° C.) is referred to as a "reference temperature", and a parameter such as a resistance value at the reference temperature is referred to as a "reference value". When the temperature of the motor 10 rises, the resistance value of the motor increases. The relationship between the motor temperature T and the motor resistance value RT is as shown in the following equation (1).
RT = R20 × (δ + T) / (δ + 20) …… Equation (1)
In the formula (1), δ is the reciprocal of the temperature coefficient of resistance of the wound copper wire, and R20 is the motor resistance reference value, that is, the motor resistance value RT of the motor at the reference temperature (20 ° C.). According to the formula (1), for example, when the temperature rises by 40 ° C. with respect to the reference temperature, the motor resistance value RT becomes about "1.16 times" the motor resistance reference value R20. Further, when the temperature rises by 70 ° C. with respect to the reference temperature, the motor resistance value RT becomes about "1.27 times" the motor resistance reference value R20. The same formula can be applied when the winding is an aluminum wire or the like.

If the temperature of the motor 10 is biased due to individual differences between the plurality of motors 10, the resistivity of the primary and secondary resistances of the motor 10 having a high temperature increases, and the motor resistance value RT increases. As a result, the torque of the electric motor is concentrated on the electric motor 10 having a low temperature, and there arises a problem that the conveyed object 12 (see FIG. 1) cannot be smoothly accelerated due to the lack of the average torque. Further, if such a state continues, the electric motor 10 in which the torque is concentrated may break down due to a long-term overload.

(Diameter difference of rotating wheel 16)
Further, in FIG. 1, if there is a difference in the diameters of the rotating wheels 16-1 and 16-2 coupled to the respective electric motors 10, the difference in the diameters of the rotating wheels causes a difference in the rotational speed of each electric motor 10. A difference occurs in the generated torque of each electric motor 10 in substantially proportional to the difference in rotation speed. Here, if the electric motor 10 is configured so that the rated slip becomes large, it is possible to suppress the difference in generated torque due to the difference in rotational speed. On the other hand, since the rated slip greatly affects the efficiency of the electric motor 10, it is preferable to reduce the rated slip when aiming at high efficiency of the motor 10. When a plurality of electric motors 10 are actually operated with the configuration as shown in FIG. 1, it is usual to secure a rated slip of a certain size because a difference in diameter of the rotating wheels occurs. If the diameter of each rotating wheel 16 is strictly controlled, it is theoretically possible to realize an electric motor 10 having a small rated slip and high efficiency. However, in that case, the maintenance of the rotating wheel 16 becomes complicated.

Next, a method of detecting the fact when the difference in the diameters of the rotating wheels becomes large will be examined. When a speed sensor is attached to the rotating shaft 14 of each electric motor 10, it can be detected that the difference in the diameter of the rotating wheels has increased according to the difference in the rotating speed of each electric motor 10. However, if an attempt is made to detect even a slight difference in the diameter of the rotating wheels, a high-sensitivity sensor is required, which causes problems such as cost increase and sensor maintenance.
Therefore, the electric motor control system 101 of the present embodiment monitors the state of the overheated state of each electric motor 10 and the difference in diameter of the rotating wheels (difference in diameter of each rotating wheel 16), and when these abnormalities occur, the state is monitored. It is intended to detect anomalies accurately.

<Principle of anomaly detection>
Figure 4 is a diagram showing an example of a mechanical frequency omega _rs and DC volume I _r1, I _r2 during acceleration.
The mechanical frequency ω _rs in the figure shows an example of the mechanical frequency during acceleration of the electric motors 10-1 and 10-2. Generally, there is a difference in the mechanical frequencies ω _rs1 and ω _rs2 of the electric motors 10-1 and 10-2, but the mechanical frequency ω _rs shown in the figure is one of ω _rs1 and ω _rs2 . As shown in the figure, the mechanical frequency ω _rs increases with the passage of time. The predetermined synchronization speeds f _L1 , f _L2 , f _H1 , and f _H2 during acceleration have a relationship of “f _L1 <f _L2 <f _H1 <f _H2 ”. Here, referred to as referred to as "f _L1 <ω _rs <f _L2", "low speed zone" range of omega _rs is, the "f _H1 <ω _rs <f _H2" range of a is omega _rs "high speed region" .. Also, call the period the machine frequency ω _rs belongs to the low-speed range and the low speed range period T _L, referred to as the period during which the machine frequency ω _rs belongs to the high-speed range and high speed range period T _H.

DC quantity I _r101, I _r201 is an example of a DC quantity I _r1, I _r2 (see FIG. 2) during the acceleration of the machine frequency omega _rs. In this example, the temperature of the motor 10-2 (see FIG. 1) is higher than the temperature of the motor 10-1, and the difference in the diameters of the rotating wheels of the motors 10-1 and 10-2 is "0". I'm assuming. Since the temperature of the motor 10-2 is higher than that of the motor 10-1, the DC amount _Ir201 for the motor 10-2 is smaller than the DC amount _Ir101 for the motor 10-1. Here, the "I _r1 -I _r2" in the low speed range period T _L is referred to as a "low speed range current difference I _L". Further, the "I _r1 -I _r2" in the high speed range period T _H referred to as "high-speed range the current difference I _H". When the rotation wheel diameter difference is small, and the low speed region current difference I _L and the high speed region current difference I _H becomes substantially equal.

Further, the direct current amount I _r102, I _R202 is another example of a DC quantity I _r1, I _r2 during the acceleration of the machine frequency omega _rs. In this example, it is assumed that the temperatures of the electric motors 10-1 and 10-2 (see FIG. 1) are equal and a difference in rotating wheel diameter occurs. That is, the diameter of the rotating wheel 16-1 is a predetermined reference value, and the diameter of the rotating wheel 16-2 is smaller than the reference value. Since the diameter of the rotating wheel 16-2 is small, even in the low speed range period T _L, the DC volume I _R202 is slightly smaller than the DC volume I _r102. However, a difference between the low-speed range the current difference I _L is remained small value. On the other hand, in the high speed range period T _H, appears largely affected by the rotation wheel diameter difference, the high-speed range the current difference I _H is relatively large value.

According to FIG. 4, the low speed region current difference I _L, the influence of the motor resistance value RT that is, the temperature is dominant, high-speed region the current difference I _H it is understood that the influence of the rotating wheel diameter difference is dominant .. Therefore, based on the measurement result of the low speed region current difference I _L, to detect the heat generation of the electric motor 10, it is possible to alert. Further, it is possible to detect and warn the difference in the diameter of the rotating wheels based on the measurement result of the high-speed range current difference I _H. However, in the actual machine, the influence of the heat generated by the electric motor 10 and the influence of the difference in the diameter of the rotating wheels occur at the same time. Therefore, in order to more accurately evaluate the influence of the heat generated by the electric motor 10 and the influence of the difference in the diameters of the rotating wheels, it is preferable to separate the respective influences.

Figure 5 is a diagram showing another example of the DC amount I _r1, I _r2 during acceleration. Since the mechanical frequency ω _rs changes with time in the same manner as that shown in FIG. 4, the illustration is omitted.
5, the DC volume I _r103, I _R203 is another example of a DC quantity I _r1, I _r2 during the acceleration of the machine frequency omega _rs (see FIG. 4). In this example, the temperature of the electric motor 10-1 is the reference temperature, and the temperature of the electric motor 10-2 is "reference temperature + 70 ° C.". Further, the diameter of the rotating wheel 16-1 (see FIG. 1) is a predetermined reference value, and the diameter of the rotating wheel 16-2 is smaller than the reference value.

Since the temperature of the electric motor 10-2 is higher than the temperature of the electric motor 10-1, the low-speed range current difference _IL is a sufficiently large value. Furthermore, since the diameter of the rotating wheel 16-2 is smaller than the diameter of the rotating wheel 16-1, the difference between the DC amounts _Ir103 and _Ir203 increases with the passage of time, and becomes a large value in the high-speed current difference I _H. There is. This high-speed range current difference I _H is a value affected by both the temperature difference and the rotating wheel diameter difference of the electric motors 10-1 and 10-2. In this case, it is advisable to obtain the corrected high-speed range current difference _IQ (not shown) by "I _Q = | I _H |-| _IL |". This correction high speed region current difference I _Q has a value influence of the rotating wheel diameter difference appeared while suppressing the influence of the temperature difference.

Further, in FIG. 5, the DC volume I _r104, I _R204 is another example of a DC quantity I _r1, I _r2 during the acceleration of the machine frequency omega _rs (see FIG. 4). In this example, the temperature of the electric motor 10-1 is the reference temperature, and the temperature of the electric motor 10-2 is "reference temperature + 70 ° C.". Further, it is assumed that the diameter of the rotating wheel 16-1 (see FIG. 1) is smaller than a predetermined reference value, and the diameter of the rotating wheel 16-2 is the reference value. Since the temperature of the electric motor 10-2 is higher than the temperature of the electric motor 10-1, the absolute value | _IL | of the low-speed current difference is a sufficiently large value. Further, since the diameter of the rotating wheel 16-1 is smaller than the diameter of the rotating wheel 16-2, the difference between the DC amounts _Ir104 and _Ir204 is reduced and inverted with the passage of time. In this case, it is advisable to obtain the corrected high-speed range current difference _IQ (not shown) by "I _Q = | I _H | + | _IL |". This correction high speed region current difference I _Q also becomes a value effects appeared rotary wheel diameter difference while suppressing the influence of the temperature difference.

By the way, in the example shown in FIG. 5, the temperatures of the electric motors 10-1 and 10-2 are premised on one being the reference temperature and the other being higher than the reference temperature. However, when the cooling functions of the electric motors 10-1 and 10-2 are reduced at the same time, the difference between the DC amounts _Ir1 and _Ir2 may not be noticeable. In such a case, it is difficult to detect the overheated state of the electric motors 10-1 and 10-2 based only on the difference between the DC amounts _Ir1 and _Ir2 .

An example thereof will be described with reference to FIG. 6 shows, the DC volume I _r1, I _r2, and the proportional signal PLL_P1 during acceleration is a diagram showing still another example.
6, the DC volume I _R105, I _R205 is a motor 10-1 and 10-2 are both reference temperature is an example of a direct current amount I _r1, I _r2 when the rotation wheel diameter difference is zero. Further, the direct current amount I _R106, I _R206 in FIG. 6, the motor 10-1 and 10-2 are both "reference temperature + 70 ℃", the DC amount when the rotation wheel diameter difference is 0 I _r1, I _r2 Is an example of. In these examples, since no significant difference appears between the difference value "I _r105- I _r205 " and the difference value "I _r106- I _r206 ", the motors 10-1, _10- based on these. It is difficult to detect the overheated state of 2.

Here, referring to FIG. 3 again, in the multipliers 62 and 64 in the phase calculator 60, the proportional gain KpPLL and the integral gain KiPLL are each multiplied by the difference value “θ _i * −θ _i ”. There is. These gains KpPLL and KiPLL are set so that the difference value “θ _i * −θ _i ” converges as soon as possible when the corresponding motor 10 is at the reference temperature. However, when the actual temperature of the electric motor 10 deviates from the reference temperature, the proportional gain KpPLL and the integrated gain KiPLL deviate from the optimum values at that temperature, so that the fluctuation range of the proportional signal PLL_P is compared with the case of the reference temperature. And get bigger. For this reason, by monitoring the fluctuation amplitude of the proportional signal PLL_P, it is possible to detect whether or not the corresponding electric motor 10 is in an overheated state.

The proportional signal PLL_P105 in FIG. 6 shows an example of the waveform of the proportional signal PLL_P1 (that is, the proportional signal PLL_P with respect to the electric motor 10-1) in the low speed region period _TL (see FIG. 4). Here, the temperature of the electric motor 10-1 is a reference temperature. The maximum value of the proportional signal PLL_P1 in low speed range period T _L is referred to as PLL_P1max, referred to as PLL_P1min the minimum value, called the difference between the low-speed range proportional signal amplitude H _L. Also referred to low speed range proportional signal amplitude H _L and a low speed range proportional signal amplitude H _L105 especially for proportional signal PLL_P105.

Further, the proportional signal PLL_P106 in FIG. 6 shows another example of the waveform of the proportional signal PLL_P1 in the low speed region period _TL (see FIG. 4). Here, the temperature of the electric motor 10-1 is "reference temperature + 70 ° C.". Further, the low-speed region proportional signal amplitude HL with respect to the proportional signal PLL_P106 is particularly referred to as a low-speed region proportional signal amplitude _{HL 106} . Comparing the proportional signals PLL_P105 and PLL_P106, a significant difference is observed between the low-speed region proportional signal amplitudes H _L105 and H _L106 . Therefore, the overheated state of the electric motor 10 can be detected by monitoring the low-speed region proportional signal amplitude _HL . Incidentally, the low-speed range proportional signal amplitude H _L of the motor 10-1 and 10-2 may be referred to as "H _L1", "H _L2".

FIG. 7 is a diagram showing an example of state determination based on the low-speed region / high-speed region current differences _IL and I _H. That is, FIG. 7 is a synthesis of the contents described with reference to FIGS. 4 to 6.
7, the low-speed range-corrected high speed region current difference I _L, when I _Q are both small, the rotation wheel diameter difference of the rotating wheels 16-1 and 16-2 is determined to be "normal". On the other hand, the temperature rise of the electric motors 10-1 and 10-2 is determined according to the low-speed region proportional signal amplitude _HL . That is, when the low-speed region proportional signal amplitude _HL is small (see, for example, _{HL 105} in FIG. 6), it can be determined to be normal. On the contrary, when the low-speed region proportional signal amplitude _HL is large (see, for example, _{HL 106} in FIG. 6), it can be determined that the signal is abnormal (overheated).

When the low-speed range current difference _IL is large and the corrected high-speed range current difference _IQ is small, it is determined that one of the motors 10 is in an overheated state (abnormal) and the difference in rotating wheel diameter between the two motors is normal. can do. Further, when the low-speed range current difference _IL is small and the corrected high-speed range current difference _IQ is large, it can be determined that an abnormality has occurred in the difference in the diameters of the rotating wheels of both motors. On the other hand, the temperature rise of the electric motors 10-1 and 10-2 is determined according to the low-speed region proportional signal amplitude _HL . Furthermore, the low speed range-corrected high speed region current difference I _L, when I _Q are both large, the temperature rise of one of the motor 10, it is determined that the abnormality in both of the rotating ring diameter difference of both the electric motor has occurred be able to.

<Operation of the first embodiment>
FIG. 8 is a flowchart of an abnormality detection routine executed by the monitoring device 40. This abnormality detection routine is executed at predetermined sampling cycles when the electric motors 10-1 and 10-2 are accelerating.
When the process proceeds to step S2 in FIG. 8, the current measurement process is executed. That is, in the monitoring device 40 (see FIG. 2), the current calculation units 42-1 and 42-2 acquire the current detection values I _u1 , I _w1 , I _u2 , and I _w2 from the current sensor 41 (see FIG. 1). To do.

Next, when the process proceeds to step S4, the current calculation units 42-1 and 42-2 calculate the states of the electric motors 10-1 and 10-2. That is, a DC quantity I _r1, I _r2, proportional signal PLL_P1, and PLL_P2, mechanical frequency omega _rs1, and omega _rs2, and outputs the. Next, when the processing proceeds to step S5, the monitoring device 40 determines the speed ranges of the mechanical frequencies ω _rs1 and ω _rs2 , and the subsequent processing is branched according to the result.

First, when both the mechanical frequencies ω _rs1 and ω _rs2 are in the low speed range, that is, when both "f _L1 <ω _rs1 <f _L2 " and "f _L1 <ω _rs2 <f _L2 " are satisfied, step S6 and subsequent steps are performed. Processing is executed. Further, when both the mechanical frequencies ω _rs1 and ω _rs2 are in the high-speed range, that is, when both "f _H1 <ω _rs1 <f _H2 " and "f _H1 <ω _rs2 <f _H2 " are satisfied, step S20 and subsequent steps are performed. Processing is executed. If neither of the two applies, the processing of this routine ends.

(Processing in the low speed range)
First, in step S6, the feature amount extraction unit 44 (see FIG. 2) executes the low-speed region feature amount extraction process. That is, a low speed range the current difference I _L = I _r1 -I _r2, the low-speed range of the electric motor 10-1 and 10-2 proportional signal difference H _L1, H _L2 (H _L shown in FIG. 6) is calculated. Then, at step S8, the abnormality determination section 48, the absolute value of the low-speed range the current difference I _L | I _L | is, whether more than a predetermined threshold I _LT is determined.

If "Yes" is determined here, the process proceeds to step S10, and it is determined whether or not "I _r1 > _Ir2 " is satisfied. If "Yes" is determined in step S10, the process proceeds to step S12, and the abnormality determination unit 48 outputs an electric motor overheat alarm signal indicating that the electric motor 10-2 is in an overheated state to the outside. On the other hand, if "No" is determined in step S10, the process proceeds to step S14, and the abnormality determination unit 48 outputs an electric motor overheat alarm signal indicating that the electric motor 10-1 is in an overheated state to the outside.

If the absolute value | _IL | is equal to or less than the threshold value I _LT , it is determined as "No" in step S8, and the process proceeds to step S16. Here, the abnormality determination section 48, "H _L1> G _L and H _L2> G _L 'determines whether or not satisfied. Here, _GL is a predetermined threshold constant for determining whether or not the amplitude of the proportional signal PLL_P is too large. If "Yes" is determined in step S16, the process proceeds to step S18, and the abnormality determination unit 48 sends an electric motor overheat alarm signal indicating that both the motors 10-1 and 10-2 are in an overheated state to the outside. Output. If "No" is determined in step S16, the processing of this routine ends.

By the way, in step S16 described above, when both " _HL1 > _GL " and " _HL2 > _GL " are satisfied, it is determined that both the electric motors 10-1 and 10-2 are in an overheated state. When only one of the "H _L1> G _L" or "H _L2> G _L" is satisfied here, the corresponding side electric motor it is conceivable to determine that the overheated state. However, overheating of the one electric motor is also performed by the low speed region current difference I _L (step S8) for, when also determined based on the low-speed range proportional signal amplitude H _L, the same event (overheating of one motor Two judgments will occur for the state). Therefore, in the present embodiment, overheating of the one of the motor, detected by the low speed region current difference I _L (step S8), and the overheating of both the motor 10-1 and 10-2 a low speed range proportional signal amplitude H It is detected based on _L (step S16).

(High-speed processing)
When both the mechanical frequencies ω _rs1 and ω _rs2 are in the high-speed range, the process proceeds to step S20 via step S5 described above, and the feature amount extraction unit 44 (see FIG. 2) performs the high-speed range feature amount extraction process. Will be executed. That is, the high-speed current difference I _H = I _r1 −I _r2 is calculated. Next, when the process proceeds to step S22, the feature amount extraction unit 44 executes the current value correction process, and the corrected high-speed range current difference _IQ is calculated.

Here, correction high-speed range the current difference I _Q is, in the case of "I _H> 0" becomes "I _H -I _L", in the case of "I _H <0" becomes "I _L -I _H". As described above, since this routine is a routine executed when the electric motors 10-1 and 10-2 are accelerating, before the processing in the high speed region after step S20 is executed, it is executed. processing in step S6 in the low speed region is performed, a low speed range current difference I _L is calculated. Low speed region current difference I _L to be used in step S22 is a low speed range current difference I _L that has been measured at low speed range which appeared immediately before the current high-speed range.

Next, when the process proceeds to step S24, the abnormality determination unit 48 determines whether or not “I _Q > _IQH ” is satisfied. Here, _IQH is a predetermined threshold constant for determining whether or not the corrected high-speed range current difference _IQ is excessive. If "No" is determined here, the processing of this routine ends. On the other hand, if it is determined as "Yes", the process proceeds to step S26, and the abnormality determination unit 48 indicates that the rotation wheel diameter difference between the rotation wheels 16-1 and 16-2 is abnormal. The signal is output to the outside, and the processing of this routine ends. The detailed contents of the rotating wheel diameter difference alarm signal are set according to the values of the low-speed range / high-speed range current differences _IL and I _H.

Here, when " _IL > 0 and I _H >0", the content of the rotating wheel diameter difference alarm signal indicates that "the diameter of the rotating wheel 16-2 is too small". Further, when " _IL > 0 and I _H <0", the content of the rotating wheel diameter difference alarm signal indicates that "the diameter of the rotating wheel 16-2 is excessive". When " _IL <0 and I _H <0", the content of the rotating wheel diameter difference alarm signal indicates that "the diameter of the rotating wheel 16-1 is too small". When " _IL <0 and I _H >0", the content of the rotary wheel diameter difference alarm signal indicates that "the diameter of the rotary wheel 16-1 is excessive".

<Effect of the first embodiment>
As described above, according to the present embodiment, the electric motor monitoring device (40) calculates the rotation speed (ω _rs ) of the corresponding electric motor (10) according to each current value (I _u , I _w ). Overheated state of any electric motor (10) or diameter difference of a plurality of rotating wheels (16) based on the calculation unit (42), the current value (I _u , I _w ) and the rotation speed (ω _rs ). The determination unit (44, 48) for detecting at least one of the abnormalities of the above is provided.
Thereby, according to the present embodiment, it is possible to detect the overheated state of the electric motor (10) or the abnormality of the diameter difference of the plurality of rotating wheels (16) based on the current values (I _u , I _w ). That is, since the temperature sensor, speed sensor, and the like can be omitted, it is possible to prevent failures while realizing labor saving in maintenance.

Further, the determination unit (44, 48) is the maximum value among a plurality of DC amounts (I _r ) when the rotation speeds (ω _rs ) of the plurality of electric motors (10) are in the low speed range within a predetermined speed range. low speed range current difference which is a difference between the minimum value and the function of calculating the (I _L), based on the low speed range current difference (I _L), the DC content of the minimum value (I _r) to the corresponding electric motor (10) It also has a function to detect the overheated state of.
As a result, the overheated state can be determined based on the low-speed current difference ( _IL ).

Further, the calculation unit (42) obtains an AC current phase angle detection value (θ _i *) based on the current value (I _u , I _w ) for any one of the electric motors (10). And the difference value (θ _i * −θ _i ) between the input AC current phase angle (θ _i ) and the AC current phase angle detection value (θ _i *) is proportionally integrated, and the difference value (θ) is performed. _It has a PLL calculation unit (56, 60, 72) that outputs an AC current phase angle (θ _i ) so that _i * −θ _i ) becomes smaller, and is proportional to the difference value (θ _i * −θ _i ). Outputs a proportional signal (PLL_P)
The determination unit (44, 48) has a function of detecting an overheated state in one electric motor (10) based on a proportional signal (PLL_P).
As a result, it is possible to detect an overheated state that occurs simultaneously in a plurality of electric motors (10).

Further, the determination unit (44, 48) is the maximum value among a plurality of DC amounts (I _r ) when the rotation speeds (ω _rs ) of the plurality of electric motors (10) are in a high speed range within a predetermined speed range. A function to calculate the high-speed range current difference (I _H ), which is the difference between the minimum value and the minimum value, and a function to detect the difference in rotating wheel diameters of a plurality of electric motors (10) based on the high-speed range current difference (I _H ). , Further prepared.
Thereby, the difference in the diameters of the rotating wheels of the plurality of electric motors (10) can be detected.

Further, the determination unit (44, 48) outputs an alarm signal when it detects at least one of the overheated state of any of the electric motors (10) and the abnormality of the diameter difference of the plurality of rotating wheels (16).
This makes it possible to notify the administrator of various abnormalities.

[Second Embodiment]
FIG. 9 is a block diagram of the electric motor control system 102 according to the second embodiment of the present invention. In the following description, the same reference numerals may be given to the parts corresponding to the respective parts of the other embodiments described above, and the description thereof may be omitted.
In FIG. 9, the electric motor control system 102 includes N electric motors 10-1 to 10-N (N is a natural number of 3 or more) and N electric motors coupled to these via rotating shafts 14-1 to 14-N. The rotating wheels 16-1 to 16-N are provided. In addition, two current sensors 41 (total of 2N) are mounted on the U phase and W phase of each electric motor 10-1 to 10-N, and these current detection values I _{u1 to} I _uN , I _w1 ~ I _wN is supplied to the monitoring device 150 (motor monitoring device).

Although not shown, the configuration of the monitoring device 150 is omitted, but in the monitoring device 40 (see FIG. 2) of the first embodiment, N current calculations are performed instead of the two current calculation units 42-1 and 42-2. It is the same as the configuration in which the part is provided. Further, (see FIG. 4) low speed range and high speed range the current difference I _L, I _H that is calculated by the feature amount extraction unit 44, a direct current of N lines in the low speed range or high speed range I _r1 ~I maximum value among the _rN Equal to the result of subtracting the minimum value from. The configurations and operations of the present embodiment other than those described above are substantially the same as those of the first embodiment.

[Third Embodiment]
FIG. 10 is a block diagram of the electric motor control system 103 according to the third embodiment of the present invention. In the following description, the same reference numerals may be given to the parts corresponding to the respective parts of the other embodiments described above, and the description thereof may be omitted.
In FIG. 10, the electric motor control system 103 includes a monitoring device 160 (electric motor monitoring device) instead of the monitoring device 40 (see FIG. 2) of the first embodiment. The configuration of the monitoring device 160 is substantially the same as that of the monitoring device 40, but the abnormality determination unit 48 outputs an electric motor overheating alarm signal and a rotating wheel diameter difference alarm signal (see FIG. 2), and inside the driving device 20. A control command is output to the command generation unit 32 of the above as necessary. Here, the control command is, for example, a command to stop or decelerate the electric motors 10-1 and 10-2, thereby operating the electric motors 10-1 and 10-2 more safely and efficiently. Can be done.

As described above, according to the present embodiment, the determination unit (44, 48) detects at least one of the overheated state of any of the electric motors (10) or the abnormality of the diameter difference of the plurality of rotating wheels (16). Then, a control command for changing the control state is output to the control unit (30).
As a result, the control state in the control unit (30) can be changed to an appropriate state.

[Fourth Embodiment]
FIG. 11 is a block diagram of the electric motor control system 104 according to the fourth embodiment of the present invention. In the following description, the same reference numerals may be given to the parts corresponding to the respective parts of the other embodiments described above, and the description thereof may be omitted.
In FIG. 11, the electric motor control system 104 includes a drive / monitoring device 170, electric motors 10-1 and 10-2, and rotary wheels 16-1 connected to these via rotary shafts 14-1 and 14-2. 16-2 and.

The drive / monitoring device 170 includes a control unit 30, an inverter 22, an abnormality detection unit 180 (electric motor monitoring device), and an average value calculation unit 182. The average value calculation unit 182 obtains the average value of the current detection values I _u1 and I _{u2 and} the average value of the current detection values I _w1 and I _w2 , and outputs these as the current detection values I _us and I _ws .

The configuration of the control unit 30 and the inverter 22 is the same as that of the first embodiment (see FIG. 1), and the configuration of the abnormality detection unit 180 is the same as that of the monitoring device 160 (see FIG. 10) of the third embodiment. The same is true. Therefore, the drive / monitoring device 170 of the present embodiment has a function that combines the functions of the drive device 20 and the monitoring device 160 of the third embodiment. The present embodiment can also be configured by adding an abnormality detection unit 180 and an average value calculation unit 182 to the existing drive device 20 (see FIG. 10).

[Fifth Embodiment]
FIG. 12 is a block diagram of the steel rolling system 105 according to the fifth embodiment of the present invention. In the following description, the same reference numerals may be given to the parts corresponding to the respective parts of the other embodiments described above, and the description thereof may be omitted.
In FIG. 12, the steel rolling system 105 includes N electric motors 10-1 to 10-N (N is a natural number of 3 or more), rotating shafts 14-1 to 14-N, and N rotating wheels 16-1. ~ 16-N, a driving device 20, and a monitoring device 150 are provided.

Further, the steel rolling system 105 includes a horizontally arranged table called a hot run table 200. The rotating wheels 16-1 to 16-N described above each include a bearing portion 210 and a roll 220, respectively. The steel rolling system 105 of the present embodiment is provided after the finish rolling mill (not shown), and a high temperature steel plate (not shown) is conveyed from the finish rolling mill.

Then, the conveyed steel plate is sandwiched between the roll 220 and the hot run table 200, and when the roll 220 is rotated by the electric motors 10-1 to 10-N, the steel plate is rolled. The rolls 220 of each rotating wheel 16 are all driven under the same conditions. Therefore, the same specifications are applied to the electric motors 10-1 to 10-N which are the drive sources of each roll 220. The configuration of the present embodiment other than the above is the same as that of the second embodiment (see FIG. 9).

The steel plate conveyed on the hot run table 200 has a considerably high temperature, and each bearing portion 210, the coupling (not shown), and the electric motor 10 are placed in a harsh operating condition. Therefore, in order to prevent a situation such as a line stop from occurring, sensors such as a temperature sensor and a speed sensor are conventionally attached to each individual diagnosis target such as the bearing portion 210 and the electric motor 10 and the detection signal is analyzed. It was common to make an abnormality diagnosis. On the other hand, according to the present embodiment, it is not necessary to attach a temperature sensor, a speed sensor, or the like to each electric motor 10, so that a situation such as a stop of the steel rolling line may occur. Moreover, it can be prevented at low cost.

[Sixth Embodiment]
FIG. 13 is a schematic view of a railway vehicle 310 according to a sixth embodiment of the present invention. In the following description, the same reference numerals may be given to the parts corresponding to the respective parts of the other embodiments described above, and the description thereof may be omitted.
In FIG. 13, the railroad vehicle 310 includes a vehicle body 312, bogies 314, 315, wheels 316, 317, 318, 319, and a drive / monitoring device 320. The bogies 314 and 315 support the vehicle body 312. The wheels 316 and 317 are mounted on the trolley 314, and the wheels 318 and 319 are mounted on the trolley 315.

FIG. 14 is a bottom view of the dolly 315.
The bogie 315 is equipped with two electric motors 10-1 and 10-2. The electric motors 10-1 and 10-2 are coupled to the axles 334 and 344 via reduction gears 332 and 342, respectively. A pair of left and right wheels 318 are mounted on the axle 334, and a pair of left and right wheels 319 are mounted on the axle 344. Although the details of the dolly 314 are not shown, they have the same structure as the dolly 315. That is, the bogie 314 is equipped with two electric motors 10-3 and 10-4 (not shown), and the railroad vehicle 310 is equipped with a total of four electric motors 10-1 to 10-4. There is.

Returning to FIG. 13, the drive / monitoring device 320 has the same configuration as the drive / monitoring device 170 of the fourth embodiment (see FIG. 11), but a total of four electric motors 10 provided in the railway vehicle 310. To monitor the state of these electric motors 10 and the like. That is, when one or more electric motors 10 are in an overheated state, the drive / monitoring device 320 detects that fact and outputs an electric motor overheat alarm signal. Further, in the example shown in FIG. 13, the rotating wheel diameters of the wheels 318 and 319 are d1 and d2, and have a relationship of "d1 <d2". Similar to the other embodiments described above, the drive / monitoring device 320 detects when the difference in the diameters of the rotating wheels of the wheels 318 and 319 becomes large, and outputs a rotation wheel diameter difference alarm signal.

When the temperature of the motor 10 rises, the resistivity of the primary and secondary resistors of the motor 10 rises, and the motor resistance value RT increases. As a result, the torques of the plurality of electric motors 10 driven in parallel are concentrated on the electric motors having a small electric motor resistance value RT, and a phenomenon occurs in which the railway vehicle 310 cannot be smoothly accelerated due to insufficient average torque. If this phenomenon continues, the normal electric motor 10 may also fail due to a long-term overload. According to the present embodiment, since such a phenomenon can be detected and the electric motor can be identified, a major failure can be prevented and labor saving of the electric motor 10 can be realized more efficiently.

In addition, although the method of managing the wheel diameter of a railway vehicle differs depending on the railway operator, it is generally maintained so that the difference in the diameter of the rotating wheels is within the specified value in the vehicle. Here, if the difference in the diameters of the rotating wheels of each wheel is strictly controlled, the output imbalance of the plurality of electric motors 10 can be suppressed, but maintenance is troublesome and it is not realistic. According to this embodiment, it is not necessary to attach sensors such as a temperature sensor and a speed sensor for each electric motor 10, and it is possible to detect an overheated state of the electric motor and an abnormality of the wheel diameter difference only from the alternating current flowing through the electric motor. Further, in the case of a railroad vehicle, since the driving pattern is substantially constant, it is possible to accurately detect overheating of the electric motor 10 by statistically processing the evaluation information with time or the occupancy rate data in the same traveling state.

[7th Embodiment]
FIG. 15 is a side view showing a configuration of a vehicle formation according to a seventh embodiment of the present invention. In the following description, the same reference numerals may be given to the parts corresponding to the respective parts of the other embodiments described above, and the description thereof may be omitted.
In FIG. 15, the rolling stock formation 300 includes railroad cars 310 and 360, and an inter-vehicle connecting portion 350 that connects the two. The railroad vehicle 310 is the same as that of the sixth embodiment (see FIG. 13). Further, the railroad car 360 is also configured in the same manner as the railroad car 310.

That is, the railroad vehicle 360 includes a bogie 364, 365, a vehicle body 362, wheels 366, 376, 368, 369, and a drive / monitoring device 370. The bogies 364 and 365 support the vehicle body 362. The wheels 366 and 367 are mounted on the trolley 364, and the wheels 368 and 369 are mounted on the trolley 365.

In the present embodiment, the drive / monitoring devices 320 and 370 exchange information with each other, and based on the information of the own vehicle and the information of the partner vehicle, the overheated state of the electric motor and the wheels 316 to 319, 366 to 369. Detects abnormalities in the diameter difference of the rotating wheels. Assuming that the railcars 310 and 360 are each one "group", the vehicle formation 300 of this embodiment is a "multi-group drive system", and based on the comparison with the other groups, the electric motor and the difference in the diameter of the rotating wheels are abnormal. Can be considered to discriminate.

[Modification example]
The present invention is not limited to the above-described embodiment, and various modifications are possible. The above-described embodiments are exemplified for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to delete a part of the configuration of each embodiment, or add / replace another configuration. In addition, the control lines and information lines shown in the figure show what is considered necessary for explanation, and do not necessarily show all the control lines and information lines necessary for the product. In practice, it can be considered that almost all configurations are interconnected. Possible modifications to the above embodiment are, for example, as follows.

(1) Since the hardware of the control unit 30, the monitoring devices 40, 150, 160, and the abnormality detection unit 180 in the above embodiment can be realized by a general computer, the algorithms shown in FIGS. 2 and 3 and FIG. 8 The program or the like shown in the above may be stored in a storage medium or distributed via a transmission line.

(2) The algorithm shown in FIGS. 2 and 3 or the program shown in FIG. 8 has been described as software-like processing using the program in each of the above embodiments, but a part or all of the algorithm is ASIC (Application). Specific Integrated Circuit; IC for specific applications), or hardware-like processing using FPGA (field-programmable gate array) or the like may be replaced.

(3) In the configuration shown in FIG. 1, only one inverter 22 is provided, but a plurality of inverters may be provided. Further, when an inverter is provided for each individual motor 10, the motor 10 may be a synchronous motor.

(4) In each of the above embodiments, in step S16 (see FIG. 8), when both " _HL1 > _GL " and " _HL2 > _GL " are satisfied, the electric motors 10-1 and 10-2 Both were determined to be overheated. However, if only one of the "H _L1> G _L" or "H _L2> G _L" is satisfied, it may be determined that the corresponding side motor is overheated.

10, 10-1 to 10-N Electric motor 14 Rotating shaft 16 Rotating wheel 22 Inverter 30 Control unit 40 Monitoring device (motor monitoring device)
41 Current sensor 42, 42-1 to 42-N Current calculation unit (calculation unit)
44 Feature extraction unit (judgment unit)
48 Abnormality judgment unit (judgment unit, abnormality judgment process)
54 Inverse tangent converter (phase detector)
56 Subtractor (PLL calculation unit)
60 Phase calculator (PLL calculation unit, rotation speed calculation unit, rotation speed calculation process)
72 Integrator (PLL calculation unit)
101-104 Electric motor control system 105 Steel rolling system 150,160 Monitoring device (motor monitoring device)
180 Anomaly detector (motor monitoring device)
220 Roll θ _i * AC current phase angle detection value θ _i * − θ _i Difference value θ _i AC current phase angle τ * Torque command ω _rs Machine frequency (rotation speed)
I _H High-speed range current difference _IL Low-speed range current difference I _Q Corrected high-speed range current difference (high-speed range current difference)
I _q * Torque current command value I _q Torque current detection value I _u , I _w , I _{u1 to} I _uN , I _{w1 to} I _wN Current detection value (current value)
PLL_P proportional signal

Claims (9)

A plurality of electric motors, each of which has a rotating shaft, a plurality of rotating wheels each coupled to the plurality of rotating shafts, one or a plurality of inverters that supply AC current to the plurality of the electric motors, and a control for controlling the inverters. An arithmetic unit connected to an electric motor control system including a unit and a current sensor for detecting the current value flowing through each of the electric motors, and calculating the rotation speed of the corresponding electric motor according to each of the electric motors.
A determination unit that detects at least one of an overheated state of any of the electric motors or an abnormality of a diameter difference between a plurality of the rotating wheels based on the current value and the rotation speed.
An electric motor monitoring device characterized by being equipped with. One of the inverters supplies an alternating current to a plurality of the electric motors.
The calculation unit calculates a plurality of DC amounts corresponding to each of the electric motors based on the current value.
The determination unit
A function of calculating a low-speed range current difference, which is the difference between the maximum value and the minimum value, among the plurality of DC amounts when the rotation speed of the plurality of electric motors is in the low-speed range within a predetermined speed range.
A function of detecting an overheated state of the electric motor corresponding to the minimum value of the DC amount based on the low-speed current difference, and
The electric motor monitoring device according to claim 1, further comprising. The calculation unit
A phase detector for obtaining an AC current phase angle detection value based on the current value for any one of the electric motors,
A PLL calculation unit that performs a proportional integration calculation on the difference value between the input AC current phase angle and the AC current phase angle detection value and outputs the AC current phase angle so that the difference value becomes smaller.
And outputs a proportional signal proportional to the difference value.
The electric motor monitoring device according to claim 2, wherein the determination unit has a function of detecting an overheated state in one of the electric motors based on the proportional signal. One of the inverters supplies an alternating current to a plurality of the electric motors.
The calculation unit calculates a plurality of DC amounts corresponding to each of the electric motors based on the current value.
The determination unit
A function of calculating a high-speed range current difference, which is the difference between the maximum value and the minimum value, among the plurality of DC amounts when the rotation speed of the plurality of electric motors is in the high-speed range within a predetermined speed range.
A function of detecting a difference in rotating wheel diameters of a plurality of the electric motors based on the high-speed current difference, and
The electric motor monitoring device according to claim 1, further comprising. The electric motor according to claim 1, wherein the determination unit outputs an alarm signal when it detects at least one of the overheated state of the electric motor or the abnormality of the diameter difference between the plurality of rotating wheels. Monitoring device. When the determination unit detects at least one of the overheated state of the electric motor or the abnormality of the diameter difference between the plurality of rotating wheels, the determination unit outputs a control command for changing the control state to the control unit. The electric motor monitoring device according to claim 1. Multiple electric motors, each with a rotating shaft,
A plurality of rotating wheels coupled to each of the plurality of rotating shafts,
Inverters that supply alternating current to the plurality of motors,
A current sensor that detects the value of the current flowing through each of the electric motors,
A rotation speed calculation unit that calculates the rotation speed of the corresponding electric motor according to each of the current values,
An abnormality determining unit that detects at least one of an overheated state of any of the electric motors or an abnormality of a plurality of diameter differences of the rotating wheels based on the current value and the rotation speed.
An electric motor control system characterized by being equipped with. Multiple electric motors, each with a rotating shaft,
A plurality of rotating wheels each coupled to the plurality of rotating shafts and each having a roll for pressing a steel plate,
Inverters that supply alternating current to the plurality of motors,
A current sensor that detects the value of the current flowing through each of the electric motors,
A rotation speed calculation unit that calculates the rotation speed of the corresponding electric motor according to each of the current values,
An abnormality determining unit that detects at least one of an overheated state of any of the electric motors or an abnormality of a plurality of diameter differences of the rotating wheels based on the current value and the rotation speed.
A steel rolling system characterized by being equipped with. Multiple electric motors, each with a rotating shaft,
A plurality of rotating wheels coupled to each of the plurality of rotating shafts,
Inverters that supply alternating current to the plurality of motors,
A current sensor that detects the value of the current flowing through each of the electric motors,
Electric motor monitoring device and
It is an electric motor monitoring method executed by the electric motor monitoring device in the electric motor control system having the above.
A rotation speed calculation process for calculating the rotation speed of the corresponding electric motor according to each of the current values, and a rotation speed calculation process.
An abnormality determination process for detecting at least one of an overheated state of any of the electric motors or an abnormality of a plurality of diameter differences of the rotating wheels based on the current value and the rotation speed.
A motor monitoring method characterized by performing.

Images