ELECTRIC RAILWAY CAR CONTROL DEVICE

Abstract: A control device for an electric railway car including a master controller (1), for providing operating instructions, a running direction detector (2, 3) for detecting the present running direction of the car, and inverter (5) for driving a main AC electric motor (6), and a control mode selector (4) which compares an operating instruction provided by the master controller (1) with the output signal provided by the running direction detector (2, 3). When the operating instruc­ tion is not in agreement with the running direction of the output signal, the control mode selector (4) applies a braking control instruction to the inverter (5) in conformance with the running direction of the output signal.

Description: The present invention relates to an electric railway car control device comprising: a master controller, for providing operating instructions; running direction detecting means for detecting a running direction of a railway car and producing an output signal representing the running direction; an inverter for driving an AC main electric motor; and control mode selecting means for comparing an instructed direction defined by an operating instruction provided by said master controller with the running direction defined by said output signal. A control device of this type is known from JP-A-59 28801. Such a device may be applied to a self-propelled railway car or railway engine, hereinafter referred to collectively as a railway car. Heretofore, in controlling an electric railway car, forward driving, backward driving, forward braking and backward braking modes are established according to instructions from the driver. If, in the case of a DC motor, a driving braking instruction is of a direction different from the present running direction of the car, then a main circuit must perform acceleration or deceleration controls as instructed by a master controller, as disclosed by Japanese Published Patent Application No. 2488/1981. In this operation, an excessively large torque will be produced by the nature of the circuit configuration, and hence an extremely large current flows in the main circuit, which may cause damage. Therefore, the conventional control device suffers from the difficulties that it is limited in operation and that it requires the provision of a protective system. An object of the invention is thus to solve the above-described problems. More specifically, an object of the invention is to provide an electric railway car control device in which, when the direction of the operating instruction is not in agreement with the actual running direction of the vehicle, control is carried out in such a manner that electric braking is effected in agreement with the car's present running direction, thus ensuring the safety of the car at all times. According to the invention the control device initially defined is characterized in that said selecting means is arranged to apply a braking control instruction to said inverter in accordance with the running direction of said output signal to thus control said AC main electric motor for braking when said instructed direction differs from the running direction. When the direction of the operating instruction is not in agreement with the vehicle running direction, electric braking is effected in accordance with the running direction. Therefore, the car can be operated with safety at all times. For a better understanding invention, and to show the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Fig. 1 is a block diagram showing a control system of an electric railway car control device constructed according to one embodiment of the invention; and Fig. 2 shows a logic flow chart showing the function of a control mode switching unit. A preferred embodiment of the invention will be described with reference to Figure l, which is a block diagram showing a control system for a railway car. In this Figure, reference numeral l designates a master controller provided on the driver's control console of the railway car which outputs driving and braking instruction on a line 1a, and forward and reverse instructions on a line lb; 2, a wheel rotation sensor for detecting the direction of rotation of the wheels of the car and the speed of rotation of the wheels; 3, a running-direction detector which, in response to the output of the wheel rotation sensor 2, determines the car's running direction and speed; 4, a control mode switching unit; and 5, a three-phase variable frequency inverter for driving an AC main electric motor 6. The master controller l includes a brake handle. The following Table 1 indicates the operating functions of the control mode switching unit with the instructions from the master controller l and the output signals of the running direction detector 3. The drawing in Fig. 2 shows the logic flow chart of the control mode switching unit 4. The running direction detector 3 sends out the output signal (forward or backward) according to the signal from the wheel rotation sensor 2. However , when the train is stopped the running direction detector 3 produces no output. In this case the three-phase variable frequency inverter 5 is controlled according to a command from the master controller 1. As it will be easily understood from the flow chart in Fig. 2, the control logic is summarized as shown in Table l. The above logic flow chart may be realized by a simple electronic circuit or by simple software for microprocessor based control device for the inverter. Hence it will not require a significant cost increase for the provision of the said logic. The control mode switching unit 4 selects a control mode according to an operating instruction received from the master controller l and an output signal from the running direction detector 3 to provide an output signal. The output signal of the control mode switching unit 4 is utilized to operate the three-phase variable frequency inverter 5 to control the AC main electric motor 6. As is apparent from the above description, whenever the content of the operating instruction of the master controller l is different from the vehicle running direction, control is carried out to effect braking so that the vehicle can be operated safely at all times. Furthermore, as driving or braking is effected according to the vehicle running direction, an effective accelerating force or braking force is always obtained, and therefore the vehicle can be operated with high efficiency. In the case when the car is being run on a slope, the operator can perform a braking operation, irrespective of the content of the operating instruction, to provide a sufficient braking effect in conformance with the vehicle running direction, which results in safety of operation. In the above-described embodiment, the wheel rotation sensor 2 may be provided on the end of the rotary shaft of the AC main electric motor 6, or it may be replaced by a main electric motor rotation sensor used to control the frequency or phase of the inverter 5. As is apparent from the above description, the electric railway car control device according to the invention includes the running direction detector 3 for detecting the vehicle running direction, and the control mode selector 4 which compares the operating instruction with the output signal of the running direction detector 3, and when the former is different from the latter, applies a brake control instruction to the inverter 5 in conformance with the running direction of the output signal. Accordingly, the vehicle can be operated in safety and with a high efficiency.

Claims: An electric railway car control device, comprising: a master controller (1), for providing operating instructions; running direction detecting means (2,3) for detecting a running direction of a railway car and producing an output signal representing the running direction; an inverter (5) for driving an AC main electric motor (6); and control mode selecting means (4) for comparing an instructed direction defined by an operating instruction provided by said master controller (1) with the running direction defined by said output signal, characterized in that: said selecting means (4) is arranged to apply a braking control instruction to said inverter (5) in accordance with the running direction of said output signal to thus control said AC main electric motor (6) for braking when said instructed direction differs from the running direction. A control device as claimed in claim 1, wherein said running direction detecting means (2,3) comprises: a wheel rotation sensor (2) for detecting the direction and speed of rotation of the wheels of said railway car; and a running direction detector (3) receiving an output of said wheel rotation sensor (2), for detecting the running direction and speed of said wheels. A control device as claimed in claim 2, wherein said wheel rotation sensor (2) is provided at an end of a rotary shaft of said main electric motor (6). A control device as claimed in claim 2, wherein said wheel rotation sensor (2) comprises a main electric motor rotation sensor for controlling at least one of the frequency and phase of said inverter. A drive arrangement for a railway car comprising an A.C. electric motor (6) and a control device according to any one of the preceding claims. A railway car comprising a drive arrangement according to claim 5.

Inventors: KOYAMA, SHIGERU C/O MITSUBISHI DENKI K.K.
Applicants: MITSUBISHI DENKI KABUSHIKI KAISHA
Application year: 1985
Main classification: B60L3
IPC codes: H02P3, B60L3, B60L9