JP5395947B2 - Electric vehicle having a load adjusting device - Google Patents

Description

  The present invention relates to an electric vehicle that effectively uses regenerative power.

  There are an electric brake and a mechanical brake as a brake device for an electric vehicle that travels by driving an AC motor by an inverter. The electric brake can recover the kinetic energy of the electric vehicle as electric energy by operating the motor as a generator. On the other hand, since the mechanical brake decelerates the electric vehicle using frictional force, the kinetic energy of the electric vehicle is released as heat and is difficult to recover. Therefore, when an electric vehicle decelerates using a brake, it is desirable to use as many electric brakes as possible from the viewpoint of energy saving.

  Generally, when an electric vehicle that travels using electric power from an overhead line tries to decelerate using an electric brake, the regenerative power generated by using the electric brake is supplied to an energy storage device mounted on the electric vehicle. Or sent to the outside of the electric vehicle via an overhead wire.

  However, there may be a case where a desired regenerative operation cannot be performed depending on the vehicle speed, overhead line voltage, or whether there is a load vehicle that consumes regenerative power in the vicinity of the host vehicle, and the regenerative efficiency is reduced.

  On the other hand, the overhead wire voltage may increase due to the regenerative operation using the electric brake. If the overhead wire voltage rises when using the electric brake, perform light load regeneration that reduces the braking force and continues the regenerative operation. However, in light load regeneration, the braking force by the electric brake is reduced, and the insufficient braking force is compensated by the mechanical brake, so that the energy efficiency is lower than in the case of decelerating only by the electric brake.

  Further, when an electric vehicle that travels by driving an AC motor with an inverter intends to decelerate by using an electric brake, VVVF control is generally performed. In VVVF control, the torque (braking force) output from the motor is limited to a value corresponding to the speed of the electric vehicle. Further, when the overhead line voltage is high, the braking force of the electric brake is limited in order to keep the motor voltage below a specified value (input voltage allowable maximum value). In such a case, the generation of regenerative power is reduced. The braking force that is insufficient with electric brakes alone is supplemented with mechanical brakes.

  Therefore, the regenerative operation cannot be performed at a desired timing, and the energy efficiency of the electric vehicle is reduced.

  The present invention improves the regenerative efficiency by securing the supply destination of regenerative power when using the electric brake, controlling the load amount of the in-vehicle load device, and maintaining the overhead line voltage at a value suitable for the regenerative operation. With the goal.

  An electric vehicle according to an embodiment of the present invention includes an AC motor driven by an inverter, torque control means for controlling the torque of the AC motor, a load to which a DC side voltage of the inverter is supplied, and an electric vehicle A load amount adjusting unit that adjusts a load amount of the load according to a DC side voltage of the inverter when the torque control unit is used for deceleration. When the vehicle speed becomes a predetermined value or less by automatic driving, the load amount is increased.

It is a figure which shows the internal circuit structure of the electric vehicle to which the load adjustment apparatus by this invention is applied. It is a figure which shows the torque reference (electric brake force) at the time of VVVF control. 3 is a graph showing a torque throttle coefficient calculated by a light load regeneration control unit 30. It is a figure which shows an example of the flow of the regenerative electric power in the electric vehicle to which this invention is applied. It is a figure which shows the other example of the flow of the regenerative electric power in the electric vehicle to which this invention is applied. It is a figure which shows other examples of the flow of the regenerative electric power in the electric vehicle to which this invention is applied. It is a figure which shows the internal circuit structure of the electric vehicle by 2nd Example of this invention. It is a figure which shows the internal circuit structure of the ATO vehicle by 3rd Example of this invention. It is a flowchart which shows operation | movement of 3rd Example of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing an internal circuit configuration of an electric vehicle to which a load adjusting device according to the present invention is applied.

  The DC overhead line voltage supplied from the current collector 10 is subjected to noise removal by an LC filter composed of a reactor 11 and a filter capacitor (FC) 14 and provided to the VVVF inverter 12. The inverter control unit (torque control means) 33 generates a gate gate signal for the VVVF inverter 12 based on the torque command, the overhead line voltage, and the like input from the light load regeneration control unit 30. The VVVF inverter 12 converts the input DC voltage into a three-phase AC voltage and drives the AC motor 13 under the control of the inverter control unit 33.

  The light load regeneration control unit 30 generates a torque command by multiplying the input torque reference by a torque coefficient in accordance with the overhead wire voltage (the voltage across the terminals of the FC 14) detected by the voltage detector 15.

  FIG. 2 is a diagram illustrating a torque reference (electric brake force) during VVVF control. As shown in FIG. 2, the torque output from the motor is set to a value corresponding to the speed of the electric vehicle and the overhead wire voltage. In FIG. 2, the vertical axis represents torque (braking force here), and the horizontal axis represents speed (vehicle speed or motor speed). 100 is an electric brake force characteristic when the overhead wire voltage is V3 (rated voltage), and 101 is an electric brake force property when the overhead wire voltage is V1 (V1> V3). FB1 to FB5 are torques corresponding to a brake notch command (brake lever angle) from the cab.

  For example, if the brake notch command is FB1 at speed B1 and overhead wire voltage V1, the motor is controlled so that the torque of FB1 is generated as an electric brake. If the brake notch command is a value equal to or greater than FB2 at the speed B1 and the overhead wire voltage V1, the motor is controlled so that the torque of Trq1 is generated as an electric brake. Here, when the brake notch command is FB4, the torque of “FB4-Trq1” is supplemented by the mechanical brake. As described above, the electric brake torque value determined based on the speed, the overhead line voltage, and the brake notch command is supplied to the light load regeneration control unit 30 as a torque reference.

  FIG. 3 is a graph showing the torque throttle coefficient calculated by the light load regeneration control unit 30.

  When the overhead wire voltage is high, the braking force of the electric brake is narrowed down in order to keep the input side voltage of the motor 13 below the maximum allowable voltage. The light load regeneration control unit 30 calculates a torque throttle coefficient according to the FC voltage (overhead voltage). In FIG. 3, V3 is a rated voltage, for example, 1500V. V1 is a voltage at which narrowing starts, and is, for example, 1650 V, 1.1 times the rated voltage. When the overhead line voltage exceeds V1, the torque throttle coefficient decreases from 1 according to the excess amount, and becomes 0 at the voltage V2. The voltage V2 is 1800V, for example. The light load regeneration control unit 30 multiplies the torque throttle coefficient calculated in this way and the input torque reference by the multiplier 32 and supplies the multiplication result to the inverter control unit 33 as a torque command.

  Returning to the description of FIG. 1, the overhead line voltage from which noise has been removed by the LC filter is supplied to the DC / DC converter 28. The DC / DC converter 28 includes a parallel circuit 34 of a diode 36a and a switching element 37a connected so that current directions are opposite to each other, and a parallel circuit 35 of a diode 36b and a switching element 37b connected similarly. The parallel circuit 34 and the parallel circuit 35 are connected in series. One end of a reactor 38 is connected to a connection node of these parallel circuits. The other end of the reactor 38 (the output end of the DC / DC converter 28) is connected to a power storage element 39 via a relay 29. The DC / DC converter 28, the relay 29, and the power storage element 39 constitute power storage means.

  The load amount adjustment unit 41 controls charging / discharging of the power storage element 39 by controlling on / off of the switching elements 37 a and 37 b and the relay 29. When the power storage element 39 is charged, the load amount adjustment unit 41 turns on the relay 29, turns off the switching element 37b, and turns on / off the switching element 37a by chopper control, that is, a pulse train signal. The frequency of this pulse train signal is, for example, several hundred Hz, and the magnitude of the charging current and the voltage of the electric power stored in the storage element are controlled according to the duty ratio. The charging current at this time is smoothed by the reactor 38. For example, when the feeding voltage is about 1500 V, the voltage of the power storage element 39 is controlled to about several hundred V to 1000 V. When holding the electric power stored in the electric storage element 39, the load amount adjustment unit 41 turns off the switching elements 37a and 37b and the relay 29.

  When discharging the electricity storage element 39, the load amount adjustment unit 41 turns on the relay 29, turns off the switching element 37a, and chopper-controls the switching element 37b. As a result, the voltage of the electric power stored in the storage element 39 is boosted by the reactor 38 and supplied to the overhead line 40 via the diode 36a, the LC filter 27, the current collector 10 and the like. At this time, the frequency of the pulse train signal for controlling the switching element 37b is, for example, several hundred Hz as in the case of charging, and the magnitude of the discharge current is controlled according to the duty ratio.

  The voltage from which noise has been removed by the LC filter is supplied to the auxiliary power supply (SIV) 20. The auxiliary power source 20 is composed of an inverter, converts an input DC voltage into an AC voltage, and supplies electric power to a load such as a cooler, a heating device, an air conditioning device, or a lighting device provided in the vehicle via a transformer 21. . The transformer 21 converts the AC voltage generated by the auxiliary power supply 20 into a voltage having a magnitude suitable for the load 22. The load amount adjustment unit 41 changes the duty ratio of the gate command for the switching circuit 29 constituting the auxiliary power source according to the overhead line voltage detected by the voltage detector 15 and controls the magnitude of the current and voltage, that is, the power. .

  If there is an electric vehicle that is in the vicinity of a power vehicle like the load vehicle 44 in FIG. 1 during the braking operation, the regenerative power generated by the electric brake is efficiently consumed by the load vehicle 44. However, when there is no power running electric vehicle in the vicinity, regenerative power is not consumed, so the overhead line voltage exceeds the upper limit value. Therefore, conventionally, when the overhead line voltage is high, as shown in FIG. 2, the electric brake and the mechanical brake are used together for the deceleration of the electric vehicle. In other words, conventionally, there is a case where the regenerative power that can be generated during the brake operation cannot be used effectively.

  In the present invention, the load amount adjusting unit 35 adjusts the load amount of the overhead line load such as the DC / DC converter 28 and the auxiliary power source 29 according to the magnitude of the overhead line voltage (FC voltage or inverter DC side voltage) during the braking operation. To do. The load amount adjusting unit 35 repeatedly performs such load amount adjustment during the brake operation period. By adjusting the load amount (power consumption) of the in-vehicle load device, the overhead line voltage is maintained at a value suitable for the regenerative operation, and as a result, the regenerative efficiency is improved.

  When the load amount is adjusted so that the overhead wire voltage becomes the narrowing start voltage (see FIG. 3), the energy efficiency is improved. Therefore, the load amount adjustment unit 35 determines whether or not the overhead line voltage is higher than the narrowing start voltage V1 or a voltage within a predetermined range including the narrowing start voltage V1 during the braking operation. When the overhead line voltage is higher than the narrowing start voltage V1 or a voltage within a predetermined range, the load amount adjusting unit 35 increases the load amount, and when it is lower, the load amount is decreased. The adjustment of the load amount may be always performed based on the overhead wire voltage, not only during the braking operation.

  Further, such adjustment of the load amount may be adjusted in accordance with the traveling state as shown in FIG. 1 in addition to the overhead line voltage described above. In other words, the load amount may be decreased during power running of the electric vehicle and may be increased during braking operation. Further, the load amount may be adjusted according to the speed of the motor or the vehicle speed. For example, when the motor speed is higher than a predetermined value during the braking operation, the load amount may be increased compared to when the motor speed is low.

  Next, the flow of regenerative power in an electric vehicle to which the present invention is applied will be described.

  FIG. 4 shows a state in which the regenerative power is supplied to the overhead line 40 through the heating device (heater) 22 a and the current collecting means 10 provided in the lower part of the seat under the control of the load amount adjusting unit 41. In this case, the load amount adjustment unit 41 controls the ratio of regenerative power supplied to the heating device 22a and the overhead line 40.

  FIG. 5 shows a state in which regenerative power is supplied to the air conditioner 22 b and the overhead line 40 under the control of the load amount adjustment unit 41. In this case, the load amount adjustment unit 41 controls the ratio of regenerative power supplied to the air conditioner 22b and the overhead line 40.

  FIG. 6 shows how regenerative power is supplied to the air conditioner 22b, the energy storage device 39, and the overhead line 40 under the control of the load amount adjustment unit 41. In this case, the load amount adjustment unit 41 controls the ratio of regenerative power supplied to the air conditioner 22b, the energy storage device 39, and the overhead line 40.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  FIG. 7 is a diagram showing an internal circuit configuration of the electric vehicle according to the present invention applied when the overhead line voltage is an AC voltage. The same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The AC voltage supplied from the current collecting means 10 is supplied to the AC / DC converter 43 via the transformer 42. The voltage detector 16 is connected to the secondary side terminal of the transformer 42, and the voltage detection value is provided to the load amount adjustment unit 41. The transformer 42 lowers the voltage of the electric power supplied from the current collecting means 10 and cuts off the DC power system connected to the current collecting means 10 and the electric vehicle in a DC manner. The AC / DC converter 43 converts the input AC voltage into a DC voltage. The circuit configuration subsequent to the AC / DC converter 43 is the same as that shown in FIG.

  In the case of the present embodiment, the load amount adjustment unit 41 is based on the AC voltage detection value detected by the voltage detector 16 or the AC feeding voltage of the overhead line 40, and the overhead wires such as the DC / DC converter 28 and the auxiliary power source 29. Adjust the load amount of the load. In the case of the second embodiment, the same effect as that of the first embodiment can be obtained.

  Next, a third embodiment of the present invention will be described.

  In the third embodiment, the load amount adjusting means according to the present invention is applied to an ATO (Automatic Train Operation) vehicle. The ATO performs automatic train operation (speed control, station stop position control) using vehicle performance, route data, and operation patterns created by operation schedules.

  The ATO vehicle has a mechanical brake and an electric brake, like the electric vehicle described in the first embodiment. When the ATO vehicle stops at a predetermined position on the station platform, for example, only the electric brake is used at the start of the braking operation. However, when the overhead wire voltage rises and the regenerative power is not absorbed by the overhead wire, the braking operation is mechanical brake. Switch to In such a case, there is generally a delay in switching to the mechanical brake. This delay may significantly reduce the stop position accuracy.

  In the ATO vehicle to which the present invention is applied, the load amount of the in-vehicle load that absorbs the regenerative power is made the same so that the brake operation is not switched to the mechanical brake immediately before the stop position.

  FIG. 8 is a diagram showing an internal circuit configuration of an ATO vehicle to which the present invention is applied.

  The route condition data storage means 51 has the gradient data (‰) of the line section on which the train travels, information related to the speed limit in the curve section, and the like. Further, the operation condition data storage means 52 has information such as the standard travel time between stations for each train type. Also, in the figure, the speed / position detecting means 53 shows the vehicle position information from the ATO vehicle upper member 54 corrected by the position correcting means 60 and the vehicle speed information obtained by calculation from the pulses generated by the TG 55. Have. The vehicle characteristic estimation means 56 estimates the travel characteristics of the vehicle from the route condition data and holds the data. The control command calculation means 57 calculates a control command to the motor and the brake device from the route condition data, the operation condition data, the train speed / position data, and the vehicle characteristic data.

  The drive / brake control device 58 generates a control signal based on the control command from the control command calculation means 57 so that the drive / brake device 59 operates in accordance with the command. The drive / brake device 59 includes a motor, an inverter, and a mechanical brake device. A train is generated based on a torque generated by the motor and a torque command from the mechanical brake drive / brake control device 58 or a brake command. Accelerate or decelerate. The driving / braking device 59 includes a torque detector 61 that detects the torque of the motor (here, braking force), and the detected torque is supplied to the control device 58. The load 45 includes the DC / DC converter 28, the storage element 39, the auxiliary power source 20, the transformer 21, the load 22 and the like as shown in FIG.

  FIG. 9 is a flowchart showing the operation of the third embodiment, and shows the control operation when the electric vehicle is stopped.

  When the electric vehicle approaches the stop position, the drive / brake control device 58 issues a brake command (ST01), and determines whether the current vehicle speed is, for example, 10 km / h or less (ST02). When the vehicle speed is higher than 10 km / h, the brake operation by the load amount adjusting unit 41 described in the first embodiment is performed (ST03). When the current vehicle speed is 10 km / h or less, control device 58 uses load amount adjustment unit 41 to increase the load amount of load 45 (ST104).

  In step ST05, the control device 58 detects the current torque value (electric brake force) using the torque detector 61, and evaluates the value. If the current torque value Trq is, for example, 10% to 95% of the desired torque value, the flow returns to step ST04, and the load amount of the load 45 is further increased. If the current torque value Trq is 95% or more of the desired torque value, for example, the control device 58 determines whether the current vehicle speed is 0 (ST06). If not, the flow moves to step ST05, and the current torque is The value Trq is evaluated again. Steps ST05 and ST06 are repeated until the electric vehicle stops.

  When the torque value Trq detected in step ST05 is 10% or less of the desired torque value, the control device 58 switches the brake operation to the mechanical brake and stops the electric vehicle (ST07, ST08).

  As described above, according to this embodiment, since the load amount of the load 45 is increased when the ATO vehicle is stopped, the possibility of switching from the electric brake to the mechanical brake during the braking operation is significantly reduced. Stop position accuracy is improved.

  The above description is an embodiment of the present invention, and does not limit the apparatus and method of the present invention, and various modifications can be easily implemented.

  The invention described in the scope of the claims at the beginning of the present application is added below.

[1] An AC motor driven by an inverter, torque control means for controlling the torque of the AC motor, a load to which a DC side voltage of the inverter is supplied, and the electric vehicle using the torque control means An electric vehicle comprising load amount adjusting means for adjusting a load amount of the load according to a DC side voltage of the inverter when decelerating.

[2] The electric vehicle according to [1], wherein the load is an air conditioning or cooling or heating device mounted on the electric vehicle, and the load amount is electric power of the load.

[3] The electric vehicle according to [1], further comprising an energy storage device, wherein the load amount is charging power of the energy storage device.

[4] The electric vehicle according to [1], wherein the load amount adjusting means increases the load amount when a DC side voltage of the inverter is larger than a predetermined value.

[5] An ATO vehicle that performs automatic driving, an AC motor driven by an inverter, torque control means for controlling the torque of the AC motor, a load to which a DC side voltage of the inverter is supplied, and the electric Load amount adjusting means for adjusting the load amount of the load according to the DC side voltage of the inverter when the vehicle decelerates using the torque control means, and the load amount adjusting means has a vehicle speed of An ATO vehicle characterized in that the load is increased when a predetermined value or less is reached.

  DESCRIPTION OF SYMBOLS 10 ... Reactor, 13 ... AC motor, 14 ... Filter capacitor, 21 ... Transformer, 32 ... Multiplier, 40 ... Overhead wire, 42 ... Transformer, 43 ... Converter

Claims (6)

An AC motor driven by an inverter;
Torque control means for controlling the torque of the AC motor;
A load to which the DC side voltage of the inverter is supplied;
Load amount adjusting means for adjusting the load amount of the load according to the DC side voltage of the inverter when the electric vehicle decelerates using the torque control means,
The load amount adjusting means is an electric vehicle that increases the load amount when the vehicle speed becomes a predetermined value or less due to automatic driving of the electric vehicle.   2. The electric vehicle according to claim 1, wherein the electric vehicle is an ATO vehicle.   The electric vehicle according to claim 2, wherein the load amount adjusting means increases the load amount when a vehicle speed becomes a predetermined value or less when the electric vehicle is stopped.   4. The electric vehicle according to claim 3, wherein the load amount adjusting means increases the load amount when the rotational speed is higher than a predetermined value when the electric vehicle is running normally, compared to when it is low.   The electric vehicle according to claim 4, wherein the load is an air conditioning, cooling, or heating device mounted on the electric vehicle, and the load amount is electric power of the load.   The electric vehicle according to claim 4, further comprising an energy storage device, wherein the load amount is charging power of the energy storage device.

Images