ELECTRICALLY PROPELLED RAILWAY VEHICLE

Abstract: In a control equipment for an electric railcar, for controlling the motor current of the railcar in accordance with a predetermined operation command 1A, a current flowing time deciding circuit 6 measures the time that the motor current exceeds a predetermined reference value, and an alarm output circuit 9 as an alarm on the basis of the output signal from the current flowing time deciding circuit 6. Thus, when the current flowing time exceeds the allowable time limit in the case that the motor current becomes excessive due to an overload during the execution of an operation command, the motor current is automatically lowered to a predetermined value, an alarm is generated at the operation command side until the content of the operation command is altered thereby lowering the motor current to a predetermined value, or until the current operation command signal is turned OFF.

Description: CONTROL EOUIPMENT FOR ELECTRIC VEHICLES The present invention relates to control equipment for electrically propelled vehicles, especially railway vehicles in particular electric railcars, which is improved to control motor current of the electric vehicle for overload operation. Fig. 3 of the drawings is a block diagram showing a prior-art control equipment of this type. In Fig. 3, numeral 1 designates an operation command receiver, which receives an operation command signal 1A inputted in accordance with a predetermined operation command and outputs its output signal la. Numeral 2 designates a motor current receiver, which receives a motor current detection signal 2A of an electric railcar, and outputs its output signal 2a. Numeral 3 designates a control circuit, which receives one of the abovementiond output signals la and 2a of two types and outputs a motor current control command signal 3a preset in response to the received signal. Numeral 4 designates a motor current signal converter. which outputs a motor current signal 4a to a motor control circuit 5 of the rear stage thereof and outputs a desired motor current from the motor control circuit 5 on the basis of the abovementioned control command signal 3a. The operation of the prior-art control equipment of this type will be explained. When the operation command signal 1A is inputted to the operation command receiver 1 in accordance with a predetermined operation command, the operation command receiver 1 inputs the operation command signal 1A and outputs an output signal la. This signal la is applied to the control circuit 3. This control circuit 3 thus outputs a preset motor current control command signal 3a in response to the output signal la. This signal la is applied to the motor current signal converter 4. The motor current signal converter.4 thus applies a motor current current signal 4a on the basis of the signal 3a to the motor control circuit 5, which thus outputs a predetermined motor current. Further, a motor current detection signal 2A is inputted to the motor current receiver 2 due to the motor current, and the output signal 2a outputted from the receiver 2 in response to the motor current detection signal 2A is applied to the control circuit 3. The motor current control command signal 3a from the control circuit 3 is continuously outputted until the output signal 2a reaches a predetermined value. The modes of the drive operation of the electric railcar by the prior-art control equipment will be explained with reference to Fig. 4. Fig. 4 is an explanatory view of the modes of the drive operations of the electric railcars by the prior-art control equipment shown in Fig. 3. In Fig. 4, the electric railcar is operated in the sequence of stopping ground points A, B, C, D and E. G denotes the gradient of a route along which the electric railcar travels. The gradient is 0 between the points A and B, the gradient is G1 between the points B and C, the gradient is G2 between the points C and C, and the gradient is G3 between the points D and E. There is a relationship of O < G2 < G3 among the gradients. In other words, an upward gradient is formed from the point A to the point E. When the electric railcar travels along the route from the point A to the point E, the load of the electric railcar increases in accordance with the gradient traveling resistance. In Fig. 4, V, V1 to V4 denote the traveling speeds of the electric railcar, I, 1o to 15 denote the motor currents, and e, Q0 to G2 are the temperature rising values of devices through which the motor current is flowed. In Fig. 4, a curve designated by a broken line indicates the state of the case that the electric railcar is operated under a normal load. The electric railcar immediately shifts to a notch-off (idling travel) between the stopping points A and B and between the points B and C after starting and accelerating, operates an electric brake, and the motor current I of the value Ig is flowed as designated by a broken line at this time. Then, the gradients are G2 and G3 between the stopping points C and D and between the points D and E, respectively, the railcar continues power drive state, the speed V of the electric railcar is balanced with the value Vl and V2, respectively and the motor current I is flowed at the values I1 and 12, respectively. The temperature rise of the devices, through which the motor current I is flowed becomes the highest temperature rise value Bl when the railcar arrives at the ground point lower than the allowable temperature rising value Bo of the device since the value of the motor current I is relatively small, and the device does not become defective. Then, the curve of a solid line in Fig. 4 indicates the state of the case that the railcar is operated by using a towing capacity as much as possible when the electric railcar is in an overload state. At this time, the flowing time of the motor current I of the value I5 slightly increases when the railcar travels between the points A and b and between the points B and C, but the temperature rising value B caused thereby is not so high, and there is a considerable margin up to the allowable temperature rising value 80. However, the speed V of the electric railcar is balanced by the values V3 and V4 with respect to the gradients G2 and G3 between the next stopping points C and D and between the points D and E, and the motor current I is flawed at the values I3 and 14. At this time, the values 3 and 14 are relatively high, and the value 15 cf the motor current I at the starting and accelerating time is continued for a long period of time. Thus, the temperature rise of the device through which the motor current is flowed is vigorous, thus arrives at the allowable temperature 00 at the ground point F, and further rises to the excessively rising value As described above, according to the prior-art control equipment of the electric railcar, the motor current is flowed in the continuously high state when the railcar travels in the overload state. Thus, the temperature rise of the device becomes excessive, causes the lifetime of the device to be shortened due to the thermal deterioration of the insulator used in the device, and in the worst case, a problem that the insulator is burnt out arises. Summary of the Invention The present invention has been made in order to eliminate the disadvantages of the prior-art control equipment as mentioned above, and has for its object to provide a control equipment for a railcar in which, when a current flowing time exceeds the allowable limit in case that a motor current becomes excessive due to an overload during the execution of an operation command, the motor current is automatically lowered to a predetermined value, an alar is generated at the operation command side to alter the content of the operation command, thereby lowering the motor current to a predetermined value or continuing the output state until the motor current is turned OFF. The control equipment for an electric railcar according to the present invention comprises a current flowing time deciding circuit for counting a time that the motor current of the electric railcar exceeds a predetermined reference value, and an alarm output circuit for generating an alarm on the basis of the output from the current flowing time deciding circuit. According to the present invention, when the time counted by the current flowing time deciding circuit exceeds the predetermined reference time, a predetermined output signal is generated, the amplitude of the motor current for the electric railcar is altered on the basis of the output signal, and an alarm output circuit is operated. Brief Description of the Drawings Fig. 1 is a block diagram showing a control equipment for an electric railcar according to an embodiment of the present invention; Fig. 2 is an explanatory view for the current flowing time decision reference in the control equipment of Fig. 1; Fig. 3 is a block diagram of the prior-art control equipment for an electric railcar; and Fig. 4 is an explanatory view of the modes of the drive operations of the electric railcar according to the prior-art control equipment of Fig. 3. Description of the Preferred Embodiment In Fig. 1, a block diagram of a control equipment for an electric railcar according to an embodiment of the present invention is shown. In Fig. 1, the corresponding parts are denoted by the same symbols as those in Fig. 3. Numeral 6 designates a current flowing time deciding circuit, numeral 7 designates a control circuit, and numeral 8 denotes an alarm signal converter. Numeral 9 designates an alarm output circuit. The current flowing time deciding circuit counts a time that the output signal la from the operation command receiver 1 exceeds the reference value while receiving the output signal la from the operation command receiver 1, and outputs a decision signal 6a for lowering the motor current to a predetermined value when the counted time exceeds the reference time allowed for the reference current value. The control circuit 7 has different operating modes according to whether the decision signal 6a is inputted or not. (I) When the decision signal 6a is not inputted to the control circuit 7, the control circuit 7 generates a predetermined motor current control signal in response to the application of the output signal la from the operation command receiver l. (II) When the decision signal 6a is inputted to the control circuit 7, the control circuit 7 forcibly alters the motor current control command signal set in response to the signal la, generates a motor current control command signal of different level preset in response to the decision signal 6a to the motor current signal converter 4 as a first output signal 7a, and generates a signal for operating an alarm to an alarm signal converter 8 as a second output signal 7b. The alarm signal converter 8 receives the second output signal 7b, outputs an alarm signal 8a. Further, the alarm output circuit 9 receives the alarm signal 8a, and generates a predetermined alarm. The alarm signal 8a is continued until the operation command operated at present is turned OFF or the content of the operation command is altered so that the amplitude of the motor current falls within a predetermined allowable range. Then, the operation of the control equipment for the electric railcar of the embodiment of the present invention described above will be explained. When the operation command signal lA is inputted to the operation command receiver 1 in accordance with the predetermined operation command, the operation command receiver 1 receives the operation command signal lA and outputs the output signal la. This signal la is applied to the control circuit 7, the control circuit 7 outputs a motor current control command signal 7a preset in response to the output signal, and the signal 7a is applied to the motor current signal converter 4. Thus, the converter 4 applies the motor current signal 4a on the basis of the signal 7a to the motor control circuit 5. The motor control circuit 5 thus outputs a predetermined motor current. The motor current detection signal 2A is inputted to the motor current receiver 2 due to the motor current, and the receiver 2 outputs the output signal 2a in response to the signal 2A to the control circuit 7, thereby providing the motor current output corresponding to the output signal la from the receiver 1. The reference current and the reference time set to the current flowing time deciding circuit 6 will be explained with reference to Fig. 2. Fig. 2 is an explanatory view for the current flowing time decision reference. In Fig. 2, T, T1 to T5 designate current flowing times, I, 10 to Ig designate motor currents, I designates a current flowing time setting curve, 4 designates the temperature rising value of the device, designates the highest allowable temperature rising value at the continuous current flowing time, L1 designates the temperature rising value limit line of the case that 8 is the temperature rising limit, and L2 designates the temperature rising curve of the case that the allowable temperature rising at the short time current flowing time is set to a value higher than 00. Of the L1 and L2, the is set in the ordinary case, but the L2 is presumed to be set when the allowable temperature is clear for a short time of the device. 10 is the continuous current flowing time allowable current value. The temperature rising limit when the To is continued is 00. When the I1 is continuously flowed, the temperature rises as the curve b or Cl, and it reaches the temperature rising limit set by the L1 or L2 within the time Tl. Similarly, when the current is continuously flowed at I2 or Ig, the temperature rises like the curve b2 to b5 or C1 to C5, and reaches the like the curve b2 to b or C to temperature rising limit in the time T2 to T5. Thus, the relationship between the I and the T is set like the curve the the excess of the current flowing time is decided, and the device to be controlled can be used within the range of the allowable temperature rise as long as the flowing current is controlled to be reduced when the excess is decided. The number of steps of the decisions set by utilizing the relationship between the I and the T can be arbitrarily selected in response to the accuracy of the decision according to whether the accuracy is precise or rough. The degree of the amplitude of the motor current may be set by performing in advance the simulation in accordance with the decision of the current flowing time deciding circuit 6. According to the present invention as described above, the control equipment for the railcar comprises the current flowing time deciding circuit and the alarm circuit. Thus, the control equipment can decide the current flowing time of the motor current when the motor is used in the overload state, automatically limits the amplitude of the motor current when exceeding the reference value, and generates a suitable operation command together by generating the alarm. Therefore, the control equipment of the invention provides advantages that the performance of the railcar can be achieved to the maximum limit within the allowable temperature rising range for the devices.

Claims: CLAIMS: 1. Control equipment for an electrically propelled vehicle. comprising means for controlling the drive motor current of the vehicle in accordance with an operation command, characterised in that the control equipment includes a current-time deciding circuit (6) responsive to the actual or required value of the motor current and adapted to determine whether the time for which the current flows exceeds a predetermined reference value corresponding to the current value, and means (7; 4,5; 8.9) for reducing the motor current and/or generating an alarm in response to the output signal from the said current time deciding circuit (6). 2. A control equipment for an electric railcar for controlling the motor current of the railcar in accordance with a predetermined operation command, characterised by a current flowing time deciding circuit (6) for counting a time that the motor current exceeds a predetermind reference value; and an alarm output circuit (9) for generating an alarm on the basis of the output signal from said current flowing time deciding circuit. 3. A control equipment as defined in claim 2. characterised in that when the measured time exceeds a preset reference time. the said current flowing time deciding circuit (6) generates a predetermined output signal, alters the amplitude of the motor current on the basis of the said output signal, and operates said alarm output circuit.

Inventors: SASAKI, KAZUO
Applicants: MITSUBISHI DENKI KABUSHIKI KAISHA
Application year: 1985
Main classification: B60L3
IPC codes: B60L3