ELECTRICAL VEHICLE CONTROL WITH A CLUTCH DISMANTLING DETECTION UNIT

Abstract

Electric vehicle control system (1, 4, 5) comprising a drive control system (50, 52) and controlling the movement of an electric vehicle by means of the drive control system (50, 52), wherein the drive control system (50, 52) comprises a plurality of induction motors (2), exactly one inverter (1) for driving the plurality of induction motors (2), a current detector (5) for detecting a total current which is a sum of motor currents flowing to the induction motors (2), and a controller (4) for controlling the inverter (1) on the basis of a current command value calculated on the basis of a torque command value, a voltage command value calculated on the basis of the detected total current, and an estimated speed value calculated on the basis of the calculated voltage command value and the detected total current, wherein the control (4) has: a clutch disconnection detection unit (40) for calculating an estimated torque value based on the total current and voltage command value and for detecting a disconnection of a clutch provided between the induction motors (2) and a drive mechanism (53, 54, 55, 56, 57) of the electric vehicle, based on the calculated estimated torque value and the torque command value.

Description

Area

[0001] The present invention relates to an electric vehicle control system applied to an electric vehicle driven by a plurality of induction motors driven by exactly one inverter. background

[0002] As illustrated in JP 2011-173441 A, a conventional electric vehicle control system typically propels an electric vehicle by controlling a torque generated by a motor connected to a wheel axle mounted on a motor wagon chassis via a gearbox and clutch. An induction motor is typically used as the motor.

[0003] JP 2014-158419 A discloses an electric vehicle control system that prevents an abnormal increase in the rotational speed of a motor by stopping the operation of an inverter when the rotational speed of the motor, detected by a speed sensor, exceeds the setpoint for the maximum speed.

[0004] JP 2003-219504 A shows a VVVF converter that converts direct current to alternating current of any frequency, a filter capacitor connected to the DC side of the VVVF converter, and an electric motor for an electric vehicle connected to the AC side of the VVVF converter forming a main circuit. wherein a speed estimation unit is provided which estimates the rotational speed of the electric motor from the output voltage command of the VVVF converter and the output current of the VVVF converter in order to obtain a speed estimate, and wherein the drive control of the electric motor is carried out by controlling the VVVF converter based on the speed estimate obtained by the speed estimation unit. In the drive control device of an electric vehicle, a speed anomaly detection unit 10 is further provided, which detects that the speed estimate obtained by the speed estimation unit has converged to an anomalous value, as well as a protection unit that stops the VVVF converter when the speed anomaly detection unit has determined that the speed estimate is converging to an anomalous value.

[0005] The publication by D. Perna and A. Del Pizzo, “An assisted speed-sensorless control of induction motor drives for railway applications,” 2016 International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles & International Transportation Electrification Conference (ESARS-ITEC), Toulouse, France, 2016, pp. 1–7, doi: 10.1109 / ESARS-ITEC.2016.7841440, presents a controlled induction motor for traction units of railway vehicles. Based on a conventional speed-sensorless vector control of induction motor drives, several numerical investigations are carried out to verify the suitability of an open-loop observer in the context of railway traction applications with their specific requirements. In particular, the focus is on control during the re-energizing phase (e.g.,after a shutdown operation) as well as during a train start-up on a steep incline - both are usually critical situations.

[0006] DE 10 2017 208 157 A1 discloses a drive system for a vehicle with at least two drive trains, each with at least one electric traction motor and a clutch, at least one inverter supplying the at least two traction motors jointly, and a control unit. The method comprises at least the steps of recording at least one drive-side rotational speed and at least one load-side rotational speed of the clutch for each of the at least two drive trains, determining at least one clutch slip value from the recorded rotational speeds, and comparing the at least one determined slip value with a predetermined threshold value.

[0007] JP 2013-135501 A discloses a control device for a motor-driven vehicle with a left and a right speed sensor for detecting the rotational speeds of the left and right wheels or the left and right engines; a determining part for comparing the detection results output by the left and right speed sensors, respectively, to determine whether an anomaly occurs on one of the left or right sides of the left and right wheels, the left and right engines, or the left and right shafts;and a control unit to reduce the torque output by the left wheel drive motor to a low value or to zero when an anomaly occurs on the side where an anomaly has been detected, namely, for example, on the left side, based on the determination made when the anomaly occurred, and to allow the torque output by the normal side, namely the right wheel drive motor, to act as a braking torque.

[0008] DE 10 2006 045 397 A1 discloses a drive device comprising an electric machine with a device for field-oriented control of the electric machine. To implement fault monitoring of an encoder of the electric machine, a comparator is provided for comparing an encoder signal from the encoder of the electric machine with a calculated value from the field-oriented control, wherein the comparator is specifically designed for detecting an encoder fault and / or a coupling fault. The coupling fault relates to a coupling for attaching the encoder to the electric machine.

[0009] EP 2 521 254 A1 discloses a power converter device for driving an induction machine and a control unit that controls the power converter device. The control unit includes a drive stop unit. The drive stop unit comprises a secondary resistance temperature sensing unit that detects the temperature rise of a secondary resistance of the induction machine, based on a current detected by the induction machine, a converter angular velocity calculated based on the current, and speed information from an electric vehicle detected by an external speed information acquisition unit.The drive stop unit further includes a drive stop signal output unit, which outputs a drive stop signal to stop a drive operation of the power converter device, based on the speed information of the electric vehicle and an output from the secondary resistance temperature detection unit.

[0010] JP 2010-288352 A shows that at least one load current or zero-phase current of an induction motor driving equipment is measured. Based on the result of a frequency analysis, at least one of the following is compared to a predefined condition: at least one of the presence / absence, frequency, and magnitude of a sideband occurring on both the high-frequency and low-frequency sides of an operating frequency fL, and at least one of the disturbance and ripple of the frequency analysis waveform. Based on the result of the comparison, a fault in the installation, which includes the induction motor, the equipment, and the coupling, is diagnosed. Brief description of the technical problem

[0011] In an electric vehicle, a clutch that serves as a connecting element between an induction motor and a gearbox can disengage while driving. During this time, an electric vehicle powered by multiple induction motors will be subjected to traction from induction motors whose clutches are not disengaged, even if some of the multiple induction motors are disengaged.

[0012] In a controller that uses the value detected by a speed sensor, as in the preceding JP 2014-158419 A, the rotational speeds of the axes to which the induction motors are connected can be individually detected. Therefore, clutch disengagement can be detected simply by detecting a difference in the rotational speeds of the axes. On the other hand, in an electric vehicle controller that uses so-called sensorless speed control, which does not use a value detected by a speed sensor for control, the rotational speeds of the axes to which the induction motors are connected cannot be individually detected. Therefore, in an electric vehicle controller that uses sensorless speed control, there is a need for a technique that detects clutch disengagement using a simple method.

[0013] The present invention was made in view of the foregoing and it is an object of the present invention to provide an electric vehicle control system that can detect a coupling disconnection by means of a simple method. Solution to the problem

[0014] To solve the aforementioned problem and achieve the objective, the present invention provides a drive control system comprising a plurality of induction motors, exactly one inverter driving the plurality of induction motors, a current detector detecting a total current (the sum of the motor currents flowing to the respective induction motors), and a controller that operates the inverter based on a current command value calculated from a torque command value, a voltage command value calculated from the detected total current, and an estimated speed value calculated from the calculated voltage command value and the detected total current. The drive control system controls the operation of an electric vehicle.The control unit features a clutch disconnection detection unit that calculates an estimated torque value based on the total current and voltage command value and detects a disconnection of a clutch provided between the induction motors and a drive mechanism of the electric vehicle, based on the calculated estimated torque value and the torque command value. Advantageous effects of the invention

[0015] According to the present invention, the electric vehicle control system can detect a disconnection of the clutch using a simple method. Brief description of drawings Fig. Figure 1 shows a block diagram of an electric vehicle drive system comprising an electric vehicle control system according to a first embodiment. Fig. Figure 2 shows a diagram representing a schematic configuration of a drive mechanism located between a wheel and an induction motor of an electric vehicle. Fig. Figure 3 shows a block diagram representing a detailed configuration of a controller according to the first embodiment. Fig. Figure 4 shows a flowchart illustrating an operating sequence for detecting a clutch separation in the first embodiment. Fig. Figure 5 shows a block diagram illustrating an example of the controller configuration according to the first embodiment, where the configuration differs from that of the Fig. 3 is. Fig. Figure 6 shows a block diagram illustrating a detailed configuration of a controller according to a second embodiment. Fig. Figure 7 shows a flowchart illustrating an operating sequence for detecting a clutch separation in the second embodiment. Fig. Figure 8 shows a block diagram illustrating a detailed configuration of a controller according to a third embodiment. Fig. Figure 9 shows a flowchart illustrating an operational sequence for detecting a clutch disconnection of a third embodiment. Fig. Figure 10 shows a block diagram illustrating an example of a hardware configuration implementing the clutch disconnect detection unit function in the first, second, and third embodiments. Fig. Figure 11 shows a block diagram that provides another example of the hardware configuration, illustrating the functions of the clutch disconnect detection unit in the first, second and third embodiments. Description of embodiments

[0016] An electric vehicle control system according to embodiments of the present invention will now be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments. Furthermore, in the following description, a physical connection and an electrical connection are not distinguished from one another and are simply referred to as a "connection".

[0017] First embodiment. Fig. Figure 1 shows a block diagram of an electric vehicle drive system 80 with an electric vehicle control system according to a first embodiment. Fig. Figure 1 shows an example of an application to a DC electric vehicle. As in Fig. As shown in Figure 1, the electric vehicle drive system 80 according to the first embodiment has an input circuit 3, a first drive group 50 and a second drive group 52.

[0018] The first drive group 50 forms a first drive control system, and the second drive group 52 forms a second drive control system. The first drive group 50 and the second drive group 52 control the electric vehicle's journey.

[0019] On the input side of input circuit 3, a positive terminal of input circuit 3 is connected to an overhead line 11 by means of a pantograph 15, and a negative terminal of input circuit 3 is in contact with a rail 18 via a wheel 16. The first drive unit 50 and the second drive unit 52 are connected in parallel on the output side of input circuit 3. These connections form an electrical circuit comprising the overhead line 11, the pantograph 15, input circuit 3, the first drive unit 50, the wheel 16, and the rail 18. Another electrical circuit is formed comprising the overhead line 11, the pantograph 15, input circuit 3, the second drive unit 52, the wheel 16, and the rail 18.

[0020] The input circuit 3 is supplied with power from the overhead line 11 via the pantograph 15. The power from the overhead line 11 via the pantograph 15 and the input circuit 3 is also supplied to the first drive group 50 and the second drive group 52.

[0021] The input circuit 3 comprises a circuit breaker 22, a filter capacitor 24, and a voltage detector 26. The circuit breaker 22 opens and closes the connection between the overhead line 11 and the first drive unit 50 and the second drive unit 52. The filter capacitor 24 smooths and stores the power supplied by the overhead line 11. The voltage detector 26 detects a voltage across the filter capacitor 24.

[0022] The first drive group 50 comprises an inverter 1, two induction motors 2, a control unit 4 and a current detector 5.

[0023] A connection terminal of the inverter 1 on a high-potential side is connected to the pantograph 15 via the circuit breaker 22 of the input circuit 3, and a connection terminal of the inverter 1 on a low-potential side is electrically connected to the wheel 16 via the input circuit 3. The inverter 1 is a power converter that converts direct current supplied by the input circuit 3 into alternating current with variable voltage and frequency. The two induction motors 2 are connected to an AC side of the inverter 1. Note that for the inverter 1, the side corresponding to the input circuit 3 is referred to as the "DC side," and the side corresponding to the induction motors 2 is referred to as the "AC side." The inverter 1 drives the two induction motors 2. The two induction motors 2 provide motive power to the electric vehicle.

[0024] The current detector 5 is arranged between the inverter 1 and a connection point 9 of the two induction motors 2. The current detector 5 detects total currents i u , i v and i w , which are the sum of the motor currents flowing to the two induction motors 2. The motor current is a phase current flowing in each phase of a single induction motor 2. The total currents i u , i v and i w , which are detected by the current detector 5, are entered into the control unit 4.

[0025] The controller 4 receives a filter capacitor voltage v FC , which is a value detected by the voltage detector 26, in addition to the total currents i u , i v and i w , as described above. The controller 4 generates gate driver signals to drive a switching element 1a of the inverter 1 based on information about the total currents i u , iv and i w , the rotational speed ω d and the filter capacitor voltage v FC The u outputs the gate driver signals to the inverter 1. The controller 4 generates pulse width modulation (PWM) signals to execute PWM control at the inverter 1, which serves as the power converter. The gate driver signals are generated using the PWM signals.

[0026] The second drive group 52 is configured similarly to the first drive group 50. Every component of the second drive group 52 is the same as that of the first drive group 50, therefore a description of it is omitted.

[0027] Although Fig. While the example of application to a direct current electric vehicle is given in Section 1, the present invention is also applicable to an alternating current electric vehicle. In the case of the alternating current electric vehicle, the input circuit 3 has a different configuration, but the controller 4 has an equivalent basic configuration. Furthermore, although Fig. Figure 1 represents two drive groups comprising the first drive group 50 and the second drive group 52; it goes without saying that the present invention can be applied to three or more drive groups. Furthermore, although Fig. While Figure 1 illustrates the example in which the two induction motors 2 are connected to the single inverter 1, the present invention is not limited to this example. A vehicle in which the induction motor 2 is mounted typically has a configuration in which the vehicle has two chassis, each with two induction motors mounted on a chassis. Therefore, when a controller 4 is mounted on a vehicle in this typical configuration, the single controller 4 drives four of the induction motors 2.

[0028] As described above, the electric vehicle drive system 80 according to the first embodiment has a configuration in which exactly one inverter 1 drives the plurality of induction motors 2 that propel the electric vehicle. The controller 4 is provided in the electric vehicle control system according to the first embodiment. Furthermore, the electric vehicle drive system 80 according to the first embodiment is not equipped with a speed sensor for detecting the rotational speed of the induction motors 2. This means that the controller 4 according to the first embodiment is a controller that performs so-called sensorless speed control, which does not use a value detected by a speed sensor for control purposes. Note that the function of the controller 4 is the same in each drive group.Therefore, the following description focuses on one of the controllers 4, which controls a single one of the drive groups.

[0029] Fig. Figure 2 shows a diagram illustrating a schematic configuration of a drive mechanism between the wheel 16 and the induction motor 2 of the electric vehicle. As in Fig. As shown in Figure 2, a coupling 54 is provided as a connecting element on a rotating shaft 53 of the induction motor 2 and is connected to a motor-side gearbox 55. A wheel-side gearbox 56 is arranged such that it meshes with the motor-side gearbox 55. The wheel-side gearbox 56 is fixed on an axle 57. The motor-side gearbox 55 and the wheel-side gearbox 56 are present in the gearboxes of the electric vehicle. The wheel 16 is connected to the axle 57. Therefore, the output side of the induction motor 2 is provided with a mechanism for transmitting the mechanical output of the induction motor 2 to the wheel 16 via the axle 57. The electric vehicle drives the wheel 16 to rotate and travels on the rail 18 with which the wheel 16 is in contact.

[0030] Fig. Figure 3 shows a block diagram illustrating a detailed configuration of the controller 4 according to the first embodiment. Fig. 3 is a part that is identical or equivalent to a part that is in Fig. 1 is shown, provided with the same reference numeral as the one assigned to the part in Fig. 1 is assigned.

[0031] The control unit 4 includes a gate driver circuit 8, a voltage control 30 and a coupling separation detection unit 40.

[0032] The gate driver circuit 8 generates the gate-to-gate driver signals to drive the switching element 1a of the inverter 1 and outputs the gate driver signals to the inverter 1. The voltage control 30 generates the PWM signals to perform PWM control on the inverter 1 and outputs the PWM signals to the gate driver circuit 8. The clutch disconnect detection unit 40 detects whether or not a clutch disconnection has occurred in the induction motor 2 to be driven.

[0033] The voltage control 30 includes a torque command value calculation unit 31, a current command value calculation unit 32, a voltage command value calculation unit 33, an integrator 34, a PWM control unit 35, a coordinate transformation unit 36 ​​and a velocity estimation unit 38.

[0034] The coordinate transformation unit 36 ​​transforms the total flows i u , i v and i w The currents detected by the current detector 5 are converted into current values ​​corresponding to the d-axis and the q-axis, which are two axes in a rotating reference frame. The current values ​​obtained after the transformation are a d-axis current i. d and q-axis current i qThe d-axis is called a flux axis, and the q-axis is called a moment axis. The d-axis and the q-axis are perpendicular with respect to their vectors. The transformation processing performed by the coordinate transformation unit 36 ​​is known, and a description of it is omitted. The d-axis flux i d and the q-axis current i q , which are obtained after the transformation by the coordinate transformation unit 36, are entered into the voltage command value calculation unit 33, the velocity estimation unit 38 and the coupling separation detection unit 40.

[0035] A start command C s is entered into the moment command value calculation unit 31. The start command C sThis is a command issued when the electric vehicle is to begin driving. The torque command value calculation unit 31 calculates a torque command value T. m *, if they are started by entering the start command C s is triggered. The moment command value T m * is a command value for the torque to be output to the induction motors 2.

[0036] The moment command value T m *, which is calculated by the torque command value calculation unit 31, is input to the current command value calculation unit 32. Based on the torque command value T m *, the current command value calculation unit 32 calculates a q-axis current command value i q *, which is a current command value for the torque axis, and a d-axis current command value i d*, which is a current command value for the flow axis. The calculation process in the current command value calculation unit 32 is known and a description of it is omitted. The q-axis current command value i q * and the d-axis current command value i d *, which are calculated by the current command value calculation unit 32, are entered into the voltage command value calculation unit 33.

[0037] The voltage command value calculation unit 33 calculates a d-axis voltage command value v d * and a q-axis voltage command value v q * based on the d-axis current command value i d * and a q-axis current command value i q *, which are calculated by the current command value calculation unit 32, and on the basis of the d-axis current i d and the q-axis current i q, which are output by the coordinate transformation unit 36. The voltage command value is a command value of the voltage output by the inverter 1. In the case of vector control, a general procedure is to perform calculations separately in the d-axis direction and the q-axis direction. The calculation processing in the voltage command value calculation unit 33 is known and a description of it is omitted. The d-axis voltage command value v d * and the q-axis voltage command value v q *, which are calculated by the voltage command value calculation unit 33, are input to the PWM control unit 35, the speed estimation unit 38 and the clutch disconnection detection unit 40.

[0038] The d-axis current i is applied to the velocity estimation unit 38. d and the q-axis current i q, which are obtained through the transformation by the coordinate transformation unit 36, and the d-axis voltage command value v d * and the q-axis voltage command value v q *, which are calculated by the voltage command value calculation unit 33, are entered. The velocity estimation unit 38 calculates an estimated velocity value ω. e based on the d-axis current i d and the q-axis current i q and the d-axis voltage command value v d * and the q-axis voltage command value v q *. The estimated velocity value ω e The value calculated by the velocity estimation unit 38 is fed into the integrator 34. Note that one method of calculating the estimated velocity value ω eThe method is known, and a detailed description is omitted. For a specific calculation method, reference is made to the content of the publication disclosed, for example, in Japanese patent no. 4437629.

[0039] The integrator 34 calculates an angular frequency by internal calculation based on the estimated velocity value ω. e , which is entered, and integrates the calculated angular frequency to calculate a phase θ i The angular frequency can be generated by adding the slip velocity of the induction motor 2 to the estimated velocity value ω. e The phase θ i The value calculated by the integrator 34 is input to the PWM control unit 35 and the coordinate transformation unit 36. The coordinate transformation unit 36 ​​uses the phase θ. i , if they the d-axis current i d and the q-axis current iq calculated.

[0040] The PWM control unit 35 generates the PWM signals to perform PWM control on the switching element 1a of the inverter 1 based on the phase θ. i , of the d-axis voltage command value v d *, and the q-axis voltage command value v q * and the filter capacitor voltage v FC The processing involved in generating the PWM signals is known, and a description of it is omitted.

[0041] Next, the clutch disconnect detection unit 40 is described. As in Fig. As shown in Figure 3, the clutch separation detection unit 40 has a torque estimation unit 41, a deviation calculation unit 42 and a determination unit 43.

[0042] The clutch disengagement detection unit 40 shows a detection unit that detects a disengagement of the clutch 54, which is provided on the rotary shaft 53 of the induction motor 2. When the induction motor 2 is driven with the clutch 54 disengaged, there is a difference between the torque command value T m *, which is based on the start command C s and an estimated moment value T e is calculated based on the total flows i u , i v and i wThe difference is calculated based on the current detected by the current detector 5, and a clutch disengagement can be detected based on this difference. The difference is particularly noticeable during startup. Note that "during startup" includes not only the case where the vehicle changes from a standstill to a driving state, but also the case where the vehicle accelerates again from a coasting position. Furthermore, in this case, the difference is not one caused by an accident or a fault, but a significant difference. The clutch disengagement detection unit 40, which is located in Fig. The one shown in section 3 is configured to use this principle.

[0043] The d-axis current i is applied to the moment estimation unit 41. d and the q-axis current i q , which are obtained through the transformation using the coordinate transformation unit 36, the d-axis voltage command value vd * and the q-axis voltage command value v q *, which are calculated by the voltage command value calculation unit 33 and the start command C s entered. If the start command C s When entered, the moment estimation unit 41 calculates the estimated moment value T. e based on the d-axis current i d , of the q-axis current i q , of the d-axis voltage command value v d *, and the q-axis voltage command value v q *. The estimated moment value T e is not a value that is externally entered or commanded, but rather an estimated value of a moment calculated by a control parameter within the controller 4. The estimated moment value T e , which is calculated by the moment estimation unit 41, is entered into the deviation calculation unit 42.

[0044] The moment command value T is assigned to the deviation calculation unit 42.m * in addition to the estimated moment value T e The deviation calculation unit 42 calculates an absolute value |ΔT| of the deviation between the moment command value T. m * and the estimated moment value T e The absolute value |ΔT| of the deviation is entered into the determination unit 43.

[0045] A reference value T is assigned to the unit of determination 43. s In addition to the absolute value |ΔT| of the deviation, the reference value T is entered. s This is a threshold value for detecting a clutch disconnection. The unit of measurement 43 compares the absolute value |ΔT| of the deviation with the reference value T. s and determines that a clutch separation has occurred if the absolute value |ΔT| of the deviation is greater than the reference value T s .

[0046] The determination unit 43 provides a separation detection signal H dThe system shuts down when a coupling disconnection is determined to have occurred. The disconnection detection signal H d The output is sent to the gate driver circuit 8. The separation detection signal H d is a control signal for intentionally stopping the operation of the gate driver circuit 8. While the separation detection signal H d The gate driver circuit 8 stops the output of the gate driver signal to the inverter 1 even if the PWM signals are input from the PWM control unit 35.

[0047] Note that although the clutch disconnect detection unit 40, described above, is configured to receive the start command C s To input the moment estimation unit 41, the start command C can be used. sThe input is to the determination unit 43. In this configuration, the processing by the moment estimation unit 41, the deviation calculation unit 42, and the determination unit 43 is always executed, regardless of whether the start command C is entered. s Then, by entering the start command C s , a result of a determination by the determination unit 43 is output to the gate drive circuit 8. Alternatively, regardless of the input of the start command C s The processing is always carried out by the moment estimation unit 41 and the deviation calculation unit 42. Then, with the input of the start command C s , the determination unit 43 begins operation and a result of a determination by the determination unit 43 is output to the gate driver circuit 8.

[0048] Next, an operation for detecting a clutch disengagement in the first embodiment will be described with reference to the Fig. 3 and Fig. 4 described. Fig. Figure 4 shows a flowchart illustrating the operational sequence for detecting a clutch disconnection in the first embodiment. Fig. 4. The processing in steps S101 and S102 is carried out by the moment estimation unit 41, the processing in step S103 is carried out by the deviation calculation unit 42, and the processing in steps S104 to S107 is carried out by the determination unit 43.

[0049] Step S101 determines whether or not the start command C s was received. If the start command C s If the start command C was not received (No in step S101), the processing in step S101 is repeated. If the start command C sOnce the response has been received (Yes in step S101), processing continues with step S102.

[0050] In step S102, the estimated moment value T is e The deviation ΔT between the estimated moment value T is calculated in step S103. e and the moment command value T m * calculated. In step S104, the absolute value |ΔT| of the deviation ΔT, calculated in step S103, is compared to the reference value T. s compared.

[0051] Here, if the absolute value |ΔT| is greater than or equal to the reference value T s If the answer is yes (in step S105), processing continues in step S106. In step S106, it is determined that "coupling disconnection has occurred" and the processing sequence continues in Fig. 4 ends.

[0052] On the other hand, if the absolute value |ΔT| is less than the reference value T sIf the answer is "No" in step S105, processing continues in step S107. In step S107, it is determined that ("coupling disconnection did not occur," and the processing sequence continues in... Fig. 4 ends.

[0053] Note that the determination process in the preceding step S105, if the absolute value |ΔT| is equal to the reference value T s The determination is "Yes" and processing continues in step S106, but the determination can be "No" and processing continues in step S107. This means that the determination can be either "Yes" or "No" if the absolute value |ΔT| is equal to the reference value T. s is.

[0054] As described above, the electric vehicle control system according to the first embodiment can disconnect the clutches of the induction motors 2 based on the torque command value T. m * and the estimated moment value T edetermine. The method of the first embodiment only needs to use command information about the torque, which is the torque command value T. m * and the estimated information about the moment, which is the estimated moment value T e is, which allows a coupling separation of the induction motors 2 to be detected using a simple method.

[0055] Furthermore, according to the first embodiment, the electric vehicle control system can detect a clutch disengagement of some of the majority of induction motors 2 and stop the drive of the drive group that includes the induction motor 2 for which the clutch disengagement was detected. As a result, even if the drive of only one drive group containing the induction motor 2 experiencing a clutch disengagement is stopped, the operation of the electric vehicle can continue through another drive group.

[0056] Fig. Figure 5 shows a block diagram illustrating an example of the configuration of the controller 4 according to the first embodiment, wherein the configuration differs from that of the Fig. 3 is. The difference to Fig. 3 is the target to which the separation detection signal H is sent. d is output. This means that the separation detection signal H d to the gate driver circuit 8 in Fig. 3 is issued, whereas in Fig. 5 the separation detection signal H d is output to the circuit breaker 22. The circuit breaker 22, which receives the disconnection detection signal H d Once received, the power supplied by the overhead line 11 is disconnected by opening a contact (not shown).

[0057] The configuration of Fig. Option 3 has the advantage that the operation of the electric vehicle can continue. On the other hand, the configuration of Fig. 5 does not stop the drive of only one drive group, which has the induction motor 2, which experiences clutch disengagement, making it impossible to continue operating the electric vehicle. However, the configuration of Fig. 5 offers an advantage in that the operation of the electric vehicle can be stopped promptly because the power supply on the side closer to the overhead line 11 can be disconnected. In the electric vehicle, a decrease in the number of induction motors 2 can contribute to the fact that driving the vehicle results in an increase in the load on a single induction motor 2. Therefore, an unintentionally large current can flow through the induction motor 2. The configuration of the Fig. 5 is effective in avoiding such a situation. Second embodiment.

[0058] Fig. Figure 6 shows a block diagram illustrating a detailed configuration of a controller 4A according to a second embodiment. The controller 4A according to the second embodiment comprises a voltage control 30A and a clutch disconnect detection unit 40A.

[0059] The clutch disconnection detection unit 40A is obtained by changing the configuration of the clutch disconnection detection unit 40 of the first embodiment, which is described in Fig. Figure 3 shows the connection from the torque estimation unit 41 to a speed converter unit 44, from the deviation calculation unit 42 to a deviation calculation unit 45, and from the determination unit 43 to a determination unit 46. Note that the other configurations are identical or equivalent to those of the first embodiment, except for the input / output signals, and are therefore designated with the same reference numerals as those in the first embodiment, thus avoiding redundant description. The input / output signals are described later.

[0060] The clutch disengagement detection unit 40A is a detection unit that detects a disengagement of the clutch 54 provided on the rotational shaft 53 of the induction motor 2. When the induction motor 2 is driven with the clutch 54 disengaged, there is a difference between the actual rotational speed of the induction motor 2 and the estimated speed value ω. e , which is based on the total flows i u , i v and i w The calculated values ​​are those detected by the current detector 5, and a clutch disconnection can be detected by the difference. The difference is particularly noticeable during start-up. The clutch disconnection detection unit 40A, as shown in Fig. The part shown in section 6 is configured to use this principle.

[0061] A vehicle speed V sThe vehicle speed information, which is an external source, is input to the speed converter unit 44. This information can be either vehicle speed information, information about the travel speed managed by a train, or actually detected travel speed information. The speed converter unit 44 converts the vehicle speed V. s into a converted velocity ω e The converted velocity ω c shows a converted value obtained by converting the vehicle speed V s is obtained in the rotational speed of the induction motor 2. The converted speed ω c The value calculated by the speed converter unit 44 is entered into the deviation calculation unit 45.

[0062] The deviation calculation unit 45 receives the estimated velocity value ω. ein addition to the converted velocity ω c The deviation calculation unit 45 calculates an absolute value |Δω| of a deviation between the converted velocity ω c and the estimated velocity value ω e The absolute value |Δω| of the deviation is entered into the unit of determination 46.

[0063] A reference value ω is assigned to the unit of determination 46. s In addition to the absolute value |Δω| of the deviation, the reference value ω is entered. s This is a threshold value for detecting a clutch separation. The unit of measurement 46 compares the absolute value |Δω| of the deviation with the reference value ω. s and determines that a clutch separation has occurred if the absolute value |Δω| of the deviation is greater than the reference value ω s , thereby increasing the separation detection signal H dis output to the gate drive circuit 8. Note that the separation detection signal H d to the gate driver circuit 8 in Fig. 6 is output, but to the circuit breaker 22 as in Fig. 5 can be issued.

[0064] Note that although the clutch disconnect detection unit 40A is described above, it is configured to receive the start command C s to enter the start command C into the speed converter unit 44 s can also be entered at the determination unit 46. In this configuration, the processing by the speed converter unit 44, the deviation calculation unit 45, and the determination unit 46 can always be carried out independently of the input of the start command C. s to be carried out. Then, by entering the start command C s, a result of the determination by the determination unit 46 is output to the gate driver circuit 8. Alternatively, regardless of the input of the start command C s The processing is always carried out by the speed converter unit 44 and the deviation calculation unit 45. Then, with the input of the start command C s The determination unit 46 begins operation and a result of the determination by the determination unit 46 is output to the gate driver circuit 8.

[0065] Next, a company will perform a detection of a clutch disengagement in the second embodiment with reference to the Fig. 6 and Fig. 7 described. Fig. Figure 7 shows a flowchart illustrating the operational sequence for detecting a clutch disconnection in the second embodiment. In the Fig. 7. The processing in steps S201 and S202 is carried out by the speed converter unit 44, the processing in step S203 is carried out by the deviation calculation unit 45, and the processing in steps S204 to S207 is carried out by the determination unit 46.

[0066] Step S201 determines whether or not the start command C is executed. s was received. If the start command C s If the start command C was not received (No in step S201), processing in step S201 is repeated. If the start command C s Once received (Yes in step S201), processing continues in step S202.

[0067] In step S202, the vehicle speed V s into the converted velocity ω c converted. In step S203, the deviation Δω between the estimated velocity value ω is calculated. e and the converted velocity ω ccalculated. In step S204, the absolute value |Δω| of the deviation Δω, which was calculated in step S203, is compared with the reference value ω. s compared. The reference value ω s is set as a criterion value to prevent false detection due to noise or similar factors. Note that the reference value ω s A fixed value or target value is provided to improve the accuracy of clutch disconnection detection.

[0068] Here, if the absolute value |Δω| is greater than or equal to the reference value ω s If the answer is yes (in step S205), processing continues in step S206. In step S206, it is determined that "coupling disconnection has occurred," and the processing sequence continues. Fig. 7 ends.

[0069] On the other hand, if the absolute value |Δω| is less than the reference value ω s(No in step S205), processing continues in step S207. In step S207, it is determined that "coupling disconnection did not occur," and the processing flow continues in Fig. 7 ends.

[0070] Note that in the determination process in the preceding step S205, if the absolute value |Δω| is equal to the reference value ω s The determination is "Yes" and processing continues in step S206, but the determination can be "No" and processing can continue in step S207. This means that the determination can be either "Yes" or "No" if the absolute value |Δω| is equal to the reference value ω. s is.

[0071] As described above, the electric vehicle control system according to the second embodiment can disengage the clutches of the induction motors 2 based on the vehicle speed V. s and the estimated velocity value ω edetect. The method of the second embodiment only needs to use input information about the speed, which is the vehicle speed V. s is and estimated information about the speed, which is the estimated speed value ω e is, which allows a coupling separation of the induction motors 2 to be detected using a simple method.

[0072] Furthermore, according to the second embodiment, the electric vehicle control unit can detect a clutch disengagement of some of the majority of induction motors 2 and stop the drive of the drive group that includes the induction motor 2 for which a clutch disengagement was detected. As a result, even if the drive of only one drive group containing the induction motor 2 experiencing the clutch disengagement is stopped, the operation of the electric vehicle can be continued by another drive group.

[0073] Note that although the separation detection signal H d to the gate driver circuit 8 in Fig. 6 is output, the separation detection signal H d to the circuit breaker 22 as in Fig. 5 can be output. Output of the separation detection signal H d The circuit breaker 22 can achieve the effect of the configuration that is in Fig. 5 is shown in the first embodiment. Third embodiment.

[0074] Fig. Figure 8 shows a block diagram illustrating a detailed configuration of a controller 4B according to a third embodiment. The controller 4B according to the third embodiment comprises a voltage control 30B and a clutch disconnect detection unit 40B.

[0075] The clutch disconnection detection unit 40B is obtained by changing the configurations of the clutch disconnection detection unit 40A of the second embodiment, which is described in Fig. Figure 6 shows the conversion from the speed converter unit 44 to a current value converter unit 47, the deviation calculation unit 45 to a deviation calculation unit 48 and the determination unit 46 to a determination unit 49.

[0076] Furthermore, according to the third embodiment, the controller 4B has a configuration in which current detectors 5a and 5b are provided between the connection point 9 and the induction motors 2, instead of the configuration in which the current detector 5 is provided between the inverter 1 and the connection point 9. The voltage controller 30B is adapted to this configuration by replacing the coordinate transformation unit 36 ​​with coordinate transformation units 36a and 36b and adding a summing unit 39. Also, Fig. 8 adapted to this configuration by referring to the induction motor on the side of the current detector 5a as induction motor 2a and the induction motor on the side of the current detector 5b as induction motor 2b.

[0077] Note that other configurations are identical or equivalent to those of the second embodiment and are therefore designated by the same reference numerals as those in the second embodiment, thus omitting a redundant description.

[0078] In the configuration of Fig. 8. The current detector 5a detects individual motor currents. u1 , i v1 and i w1 , which flow to the induction motor 2a. The current detector 5b detects individual motor currents i u2 , i v2 and i w2 , which flow to the induction motor 2b.

[0079] The detected values ​​of the motor currents i u1 , i v1 and i w1 The currents detected by the current detector 5a are input into the coordinate transformation unit 36a. The coordinate transformation unit 36a transforms the motor currents i u1 , i v1 and i w1, detected by the current detector 5a, in d-axis and q-axis current values. The current values ​​obtained after the transformation are a d-axis current i d1 and a q-axis current i q1 The d-axis current i d1 and the q-axis current i q1 The values ​​obtained after transformation by the coordinate transformation unit 36a are entered into the summing unit 39. Also, from the d-axis stream i d1 and the q-axis current i q1 , the q-axis current i q1 input to the deviation calculation unit 48 of the clutch separation detection unit 40B.

[0080] The detected values ​​of the motor currents i u2 , i v2 and i w2 The currents detected by the current detector 5b are input to the coordinate transformation unit 36b. The coordinate transformation unit 36b transforms the motor currents i u2 , i v2 and i w2, detected by the current detector 5b, in d-axis and q-axis current values. The current values ​​obtained after the transformation are a d-axis current i d2 and a q-axis current i q2 The d-axis current i d2 and the q-axis current i q2 The values ​​obtained after transformation by the coordinate transformation unit 36b are entered into the summing unit 39. Also, from the d-axis stream i d2 and the q-axis current i q2 , the q-axis current i q2 entered into the deviation calculation unit 48 of the clutch separation detection unit 40B.

[0081] The summing unit 39 sums the d-axis current i d1 and the d-axis current i d2 , sums the q-axis current i q1 and the q-axis current i q2and outputs the summed values ​​to the voltage command value calculation unit 33 and the velocity estimation unit 38. The output of the summing unit 39 is the d-axis current i. d and the q-axis current i q , which are obtained by summing the motor currents flowing to the induction motor 2a and the motor currents flowing to the induction motor 2b.

[0082] The clutch disengagement detection unit 40B is a detection unit that detects a disengagement of the clutch 54 provided on the rotary shaft 53 of the induction motor 2. When the induction motor 2 is driven with the clutch 54 disengaged, a difference exists between the actual motor currents flowing to the individual induction motors 2 and the q-axis current command value i. q *, which is based on the moment command value T m* is calculated, and a clutch disengagement can be detected by the difference. The difference is particularly noticeable during start-up. The difference is also particularly noticeable in the q-axis current component. The clutch disengagement detection unit 40B, which is in Fig. Figure 8 is configured to use this principle.

[0083] The q-axis current command value i is sent to the current value converter unit 47. q *, which is calculated by the current command value calculation unit 32 and the start command C s entered. If the start command C s When a value is entered, the current value converter unit 47 converts the q-axis current command value i. q *, which is a q-axis command value for motor currents flowing to the two induction motors 2a and 2b, into a q-axis current command value i q1 * for each of the induction motors 2a and 2b. The q-axis current command value i q1*, which is obtained after conversion by the current value converter unit 47, is entered into the deviation calculation unit 48.

[0084] In addition to the q-axis current command value i q1 *, to the deviation calculation unit 48, the q-axis current i q1 , which is obtained by transformation through the coordinate transformation unit 36a, and the q-axis current i q2 , which is obtained by transformation through the coordinate transformation unit 36b, is entered. The deviation calculation unit 48 calculates an absolute value |ΔI1| of a deviation between the q-axis current command value i q1 * and the q-axis current i q1 and an absolute value |ΔI2| of a deviation between the q-axis current command value i q2 * and the q-axis current i q2 The absolute values ​​|ΔI1| and |ΔI2| of the deviations are entered into the determination unit 49.

[0085] A reference value I is assigned to the unit of determination 49. s In addition to the absolute values ​​|ΔI1| and |ΔI2| of the deviations, the reference value I is also entered. s is a threshold value for detecting a clutch separation. The determination unit 49 compares each of the absolute values ​​|ΔI1| and |ΔI2| of the deviations with the reference value I. s The determination unit 49 determines that a clutch separation has occurred in the induction motor 2a if the absolute value |ΔI1| of the deviation is greater than the reference value I s , thereby increasing the separation detection signal H d The output is sent to the gate driver circuit 8. The determination unit 49 also determines that a coupling separation has occurred in the induction motor 2b if the absolute value |ΔI2| of the deviation is greater than the reference value I. s , thereby increasing the separation detection signal H dis output to the gate driver circuit 8. Note that the separation detection signal H d to the gate driver circuit 8 in Fig. 8 is output, but can be connected to the circuit breaker 22 as in Fig. 5 will be issued.

[0086] Fig. Figure 8 represents the configurations in which the q-axis current command value i q * is entered into the current value converter unit 47 and the q-axis current command value i q1 *, the q-axis current i q1 and the q-axis current i q2 The deviation calculation unit 48 can be entered, but the present invention is not limited to these configurations. In addition to these configurations, the d-axis current command value i can be d * be entered into the current value converter unit 47 and the d-axis current command value i d1 *, the d-axis current i d1 and the d-axis current i d2Values ​​can be entered into the deviation calculation unit 48. This means that, in addition to the command values ​​and the current values ​​of the q-axis current, the command values ​​and the current values ​​of the d-axis current can be used to determine a clutch disconnection.

[0087] Furthermore, although the clutch disconnect detection unit 40B is configured as explained above, the input of the start command C s The start command C can be entered into the current value converter unit 47. s The input is to the determination unit 49. In this configuration, the processing by the current value converter unit 47, the deviation calculation unit 48, and the determination unit 49 is always performed regardless of whether the start command C is entered. s Then, by entering the start command C s, a result of a determination by the determination unit 49 is output to the gate driver circuit 8. Alternatively, regardless of the input of the start command C s The processing operations are always performed by the current value converter unit 47 and the deviation calculation unit 48. Then, with the input of the start command C s , the determination unit 49 begins operation and a result of a determination by the determination unit 49 is output to the gate driver circuit 8.

[0088] Next, an operation of a clutch disengagement detection system in the third embodiment will be described with reference to the Fig. 8 and Fig. 9 described. Fig. Figure 9 shows a flowchart illustrating an operational sequence for detecting a clutch disconnection in the third embodiment. Fig. 9. The processing in steps S301 and S302 is carried out by the current value converter unit 47, the processing in step S303 is carried out by the deviation calculation unit 48, and the processing in steps S304 to S307 is carried out by the determination unit 49.

[0089] Step S301 determines whether or not the start command C is executed. s was received. If the start command C s If the start command C was not received (No in step S301), processing in step S301 is repeated. If the start command C s Once the response has been received (Yes in step S301), processing continues in step S302.

[0090] In step S302, the q-axis current command value i is set. q * in the q-axis current command value i q1 * converted for a motor. In step S303, deviations ΔI1 and ΔI2 between the q-axis current command values ​​i are calculated. q1 * and i q2* and the q-axis currents i q1 and i q2 The values ​​are calculated based on the detected values. In step S304, the absolute values ​​|ΔI1| and |ΔI2| of the deviations ΔI1 and ΔI2 are compared with the reference value I in step S303. s compared.

[0091] Here, if at least one of the absolute values ​​|ΔI1| and |ΔI2| is greater than or equal to the reference value I s If the answer is yes (in step S305), processing continues in step S306. In step S306, it is determined that "coupling disconnection has occurred" and the processing sequence continues in Fig. 9 ends.

[0092] On the other hand, if the absolute values ​​|ΔI1| and |ΔI2| are both less than the reference value I s If the answer is no (No in step S305), processing continues in step S307. In step S307, it is determined that "coupling disconnection did not occur" and the processing sequence continues in Fig. 9 ends.

[0093] Note that in the determination process in step S305, as above, if the absolute values ​​|ΔI1| and |ΔI2| are equal to the reference value I s The determination is "Yes" and processing continues in step S306, but the determination can be "No" and processing can continue in step S307. This means that the determination can be either "Yes" or "No" if the absolute values ​​|ΔI1| and |ΔI2| are equal to the reference value I. s are.

[0094] As described above, the electric vehicle control system according to the third embodiment can perform a clutch disconnection of the induction motors 2 based on the q-axis currents i q1 and i q2 detect, which are calculated on the basis of the detected values ​​individual motor currents flowing to the corresponding induction motors 2a and 2b, and the q-axis current command value i q1* for a motor based on the q-axis current command value i q * is calculated. As described above, the q-axis currents i q1 and i q2 The detected values ​​of the currents flowing to the corresponding induction motors 2a and 2b are used to calculate the currents. Accordingly, the method of the third embodiment only needs to use one control parameter, which is the q-axis current command value i. q * is and detected information from the current detectors 5a and 5b, and can therefore detect a coupling separation of the induction motor 2 by a simple procedure.

[0095] Furthermore, according to the third embodiment, the electric vehicle control unit can detect a clutch disengagement of the induction motor 2a or 2b and stop the drive of the drive group that includes the induction motor 2a or 2b for which a clutch disengagement was detected. As a result, even if the drive of only one drive group that includes the induction motor 2a or 2b experiences a clutch disengagement, the operation of the electric vehicle can continue via another drive group.

[0096] The electric vehicle control unit according to the third embodiment can also identify which of the induction motors 2a and 2b has a clutch disengagement. This can achieve an effect that makes troubleshooting and maintenance easier than with the electric vehicle control units of the first and second embodiments.

[0097] Note that although the separation detection signal Hd to the gate driver circuit 8 in Fig. 8 is output, the separation detection signal H d to the circuit breaker 22 in Fig. 5 can be output. Output of the separation detection signal H d The circuit breaker 22 can achieve the effect of the configuration that is in Fig. Figure 5 is shown, which is described in the first embodiment.

[0098] Finally, a hardware configuration is described that implements the functions of the clutch disconnection detection unit 40 in the first embodiment, the functions of the clutch disconnection detection unit 40A in the second embodiment, and the functions of the clutch disconnection detection unit 40B in the third embodiment are described with reference to the Fig. 10 and Fig. 11 described.

[0099] If each function of the clutch disconnect detection unit 40, the clutch disconnect detection unit 40A, or the clutch disconnect detection unit 40B is implemented, the hardware can include a processor 100 that performs an arithmetic operation, a memory 102 that stores a program that is read by the processor 100, and an interface 104 that inputs and outputs signals as shown in Fig. 10 shown.

[0100] The processor 100 can be an arithmetic unit, a microprocessor, a microcomputer, a central processing unit (CPU), or a digital signal processor (DSP). The memory 102 can comprise, for example, non-volatile or volatile semiconductor memory such as random access memory (RAM), read-only memory (ROM), flash memory, erasable programmable memory (EPROM), or electrical EPROM (EEPROM (registered trademark)), a magnetic disk, a flexible disk, an optical disk, a compact disk, a minidisk, or a digital versatile disk (DVD).

[0101] Memory 102 stores a program that executes each function of the clutch disconnect detection unit 40, clutch disconnect detection unit 40A, or clutch disconnect detection unit 40B. Processor 100 transmits and receives necessary information via interface 104 and also executes the program stored in memory 102, thereby performing various types of arithmetic operations as described in the first, second, and third embodiments. The result of processing by processor 100 can be stored in memory 102.

[0102] Furthermore, the processor can be 100 and the memory 102, which are in Fig. 10 are shown, by a processing circuit 103 as in Fig. 11 will be replaced.

[0103] The processing circuit 103 corresponds to a single circuit, a complex circuit, a programmed processor, a parallel-programmed processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination of these.

[0104] The configuration shown in the preceding embodiment is merely an example of the content of the present invention and can therefore be combined with other known techniques or partially omitted and / or modified without departing from the scope of the present invention. Reference symbol list

[0105] 1 Inverter; 1a Switching element; 2, 2a, 2b Induction motor; 3 Input circuit; 4, 4A, 4B Control; 5, 5a, 5b Current detector; 8 Gate driver circuit; 9 Connection point; 11 Overhead line; 15 Pantograph; 16 Wheel; 18 Rail; 22 Circuit breaker; 24 Filter capacitor; 26 Voltage detector; 30, 30A, 30B Voltage control; 31 Torque command value calculation unit; 32 Current command value calculation unit; 33 Voltage command value calculation unit; 34 Integrator; 35 PWM control unit; 36, 36a, 36b Coordinate transformation unit; 38 Velocity estimation unit; 39 Summer; 40, 40A, 40B Coupling disconnect detection unit; 41 Torque estimation unit; 42, 45, 48 Deviation calculation unit; 43, 46, 49 Determination unit; 44 Speed ​​converter unit; 47 Current value converter unit; 50 First drive group; 52 Second drive group; 53 Rotary shaft; 54 Clutch; 55 Engine-side gearbox; 56 Wheel-side gearbox; 57 Axle; 80 Electric vehicle drive system; 100 Processor;102 Memory; 103 Processing circuit; 104 Interface.;

Claims

[1] Electric vehicle control system (1, 4, 5) comprising a drive control system (50, 52) and controlling the movement of an electric vehicle by means of the drive control system (50, 52), wherein the drive control system (50, 52) comprises a plurality of induction motors (2), exactly one inverter (1) for driving the plurality of induction motors (2), a current detector (5) for detecting a total current which is a sum of motor currents flowing to the induction motors (2), and a controller (4) for controlling the inverter (1) on the basis of a current command value calculated on the basis of a torque command value, a voltage command value calculated on the basis of the detected total current, and an estimated speed value calculated on the basis of the calculated voltage command value and the detected total current, wherein the control (4) has: a clutch disconnection detection unit (40) for calculating an estimated torque value based on the total current and voltage command value and for detecting a disconnection of a clutch provided between the induction motors (2) and a drive mechanism (53, 54, 55, 56, 57) of the electric vehicle, based on the calculated estimated torque value and the torque command value. [2] Electric vehicle control unit (1, 4, 5) according to claim 1, wherein the clutch disconnection detection unit (40) comprises: an estimation unit (41) for estimating the estimated moment value; a calculation unit (42) for calculating an absolute value of a deviation between the moment command value and the estimated moment value; and a determination unit (43) for comparing the absolute value of the deviation with a reference value and for determining that a coupling separation has occurred if the absolute value of the deviation is greater than the reference value. [3] Electric vehicle control system (1, 4A, 5) comprising a drive control system (50, 52) and controlling the driving of an electric vehicle by means of the drive control system (50, 52), wherein the drive control system (50, 52) comprises a plurality of induction motors (2), exactly one inverter (1) for driving the plurality of induction motors (2), a current detector (5) for detecting a total current which is a sum of motor currents flowing to the induction motors (2), and a controller (4A) for controlling the inverter (1) on the basis of a voltage command value calculated on the basis of a torque command value and the detected total current, and an estimated speed value calculated on the basis of the calculated voltage command value and the detected total current, wherein the controller (4A) has: a clutch disconnection detection unit (40A) for detecting a disconnection of a clutch provided between the induction motors (2) and a drive mechanism (53, 54, 55, 56, 57) of the electric vehicle, based on the estimated speed value and a rotational speed of the induction motors (2) calculated using a driving speed of the electric vehicle. [4] Electric vehicle control unit (1, 4A, 5) according to claim 3, wherein the clutch disconnection detection unit (40A) comprises: a conversion unit (44) for converting the driving speed of the electric vehicle into the rotational speed of the induction motors (2); a calculation unit (45) for calculating an absolute value of a deviation between the rotational speed and the estimated speed value; and a determination unit (46) for comparing the absolute value of the deviation with a reference value, and for determining that a coupling separation has occurred if the absolute value of the deviation is greater than the reference value. [5] Electric vehicle control system (1, 4B, 5a, 5b) comprising a drive control system (50, 52) and controlling the driving of an electric vehicle by means of the drive control system (50, 52), wherein the drive control system (50, 52) comprises a plurality of induction motors (2a, 2b), exactly one inverter (1) for driving the plurality of induction motors (2a, 2b), a plurality of current detectors (5a, 5b) for appropriately detecting individual motor currents flowing to the induction motors (2a, 2b), and a controller (4B) for controlling the inverter (1) on the basis of a current command value calculated on the basis of a torque command value, a voltage command value calculated on the basis of a sum of the individual detected motor currents, and an estimated speed value calculated on the basis of the calculated voltage command value and the sum of the The value of the motor currents is calculated, whereby the control (4B) has: a clutch disconnect detection unit (40B) for detecting a disconnection of a clutch provided between each of the induction motors (2a, 2b) and a drive mechanism (53, 54, 55, 56, 57) of the electric vehicle, based on a q-axis current calculated on the basis of a detected value of each of the individual motor currents flowing to each of the induction motors (2a, 2b) and a q-axis current command value of the current command value. [6] Electric vehicle control unit (1, 4B, 5a, 5b) according to claim 5, wherein the clutch disconnect detection unit (40B) comprises: a conversion unit (47) for converting the q-axis current command value into a q-axis current command value for one of the induction motors (2a, 2b); a calculation unit (48) for calculating an absolute value of a deviation between the q-axis current of each of the induction motors (2a, 2b) and the q-axis current command value; and a determination unit (49) for comparing the absolute value of the deviation with a reference value and for determining that a coupling separation has occurred if the absolute value of the deviation is greater than the reference value.

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