Electric vehicle

Abstract

The present invention increases electric power supply efficiency. An electric vehicle according to the present invention has an electric motor coupled to wheels, an accumulator connected to the electric motor, an electric power reception unit that receives electric power from an external power supply, a charger connected to the electric power reception unit and the accumulator, and a control system that controls the electric motor. The electric vehicle includes, as travel modes, a first travel mode and a second travel mode smaller in regenerative electric power at the time of vehicle braking than the first travel mode. The control system executes the first driving mode at the time of no-electric power supply which stops the charger and executes the second driving mode at the time of travel electric power supply which operates the charger.

Description

Electric vehicles

[0001] The present disclosure relates to electric vehicles.

[0002] Electric vehicles, plug-in hybrid vehicles, and other electrically powered vehicles are equipped with power storage devices such as lithium-ion batteries. To ensure a sufficient driving range for an electric vehicle, the capacity of the power storage device needs to be increased, but increasing the capacity of the power storage device increases the cost of the electric vehicle.

[0003] To address this issue, electric vehicles equipped with power receiving devices such as collector arms and pantographs have been developed (see Patent Documents 1 to 4). Electric vehicles equipped with a power receiving device can receive power via the power receiving device from contact wires or the like installed in power supply lanes on expressways or the like. In other words, the electric vehicle can be driven while charging the power storage device, which allows the capacity of the power storage device to be reduced while maintaining the driving range.

[0004] Patent Publication No. 2019-506114 International Publication No. 2015 / 146393 Patent Publication No. 2016-522666 International Publication No. 2011 / 135870

[0005] However, since the area where power supply lanes are installed is limited, there is a need to improve the efficiency of power supply from the power supply lanes in order to reduce the capacity of the power storage unit while maintaining the cruising distance.

[0006] According to the present disclosure, the electric vehicle is an electric vehicle that is powered from an external power source while traveling, and includes an electric motor connected to wheels, a power storage device connected to the electric motor, a power receiving unit that receives power from the external power source, a charger that is connected to the power receiving unit and the power storage device, and a control system that has a processor and memory that are communicatively connected to each other and controls the electric motor, wherein the electric vehicle has a first traveling mode and a second traveling mode that generates less regenerative power during vehicle braking than the first traveling mode, and the control system executes the first traveling mode when the charger is stopped and not supplying power, and executes the second traveling mode when the charger is activated and power is being supplied for traveling.

[0007] According to the present disclosure, it is possible to improve power supply efficiency.

[0008] FIG. 1 is a diagram showing an example of a configuration of an electric vehicle according to an embodiment of the present disclosure; FIG. 2 is a diagram showing an example of a power supply lane set on a motorway or the like; FIG. 3 is a diagram showing an electric vehicle and power supply equipment as viewed from the direction of arrow III in FIG. 1; FIG. 4 is a diagram showing an example of an electric vehicle and a control system; FIG. 5 is a diagram showing an example of a basic structure of a control unit; FIG. 6 is a flowchart showing an example of an execution procedure for mode switching control; FIG. 7 is a timing chart showing an example of an operating status of various devices in mode switching control; FIG. 8 is a diagram showing an example of a running status of an electric vehicle; FIG. 9 is a diagram showing an example of a configuration of an electric vehicle according to another embodiment of the present disclosure; FIG. 10 is a timing chart showing an example of an operating status of various devices in mode switching control.

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. In the following description, identical or substantially identical configurations and elements are designated by the same reference numerals and will not be described repeatedly.

[0010] <First embodiment> <Vehicle overview> Fig. 1 is a diagram showing an example configuration of an electric vehicle 10 according to an embodiment of the present disclosure. As shown in Fig. 1, the electric vehicle 10 has an electric axle 13 equipped with a traction motor 11 and a differential 12. The differential 12 is connected to the traction motor 11 via a gear train 14, and the differential 12 is connected to rear wheels 16 via axles 15. In this way, the traction motor (electric motor) 11 is connected to the rear wheels (wheels) 16.

[0011] An inverter 21 is connected to the traction motor 11 via a current line 20, and a battery pack 23 is connected to the inverter 21 via a current line 22. The battery pack 23 has a battery module 24 made up of a plurality of battery cells. A charger 26 is connected to the current line 22 via a current line 25, and a current collection unit 28 is connected to the charger 26 via a current line 27. In this way, the battery module (power storage body) 24 is connected to the traction motor 11, and the charger 26 is connected to the current collection unit (power receiving unit) 28 and the battery module 24.

[0012] Above the electric vehicle 10, contact wires 101a, 101b of a power supply facility 100 installed in the power supply lane L1 of the expressway are located. Furthermore, a current collecting unit 28 installed on the upper portion of the vehicle body of the electric vehicle 10 has pantographs 30a, 30b that can move up and down. As indicated by arrow α in FIG. 1 , by raising the pantographs 30a, 30b of the current collecting unit 28, the sliders 31a, 31b of the pantographs 30a, 30b can be brought into contact with the contact wires 101a, 101b. By bringing the sliders 31a, 31b into contact with the contact wires 101a, 101b in this manner, the battery module 24 is connected to the contact wires 101a, 101b via the charger 26 and the current collecting unit 28. This allows the electric vehicle 10 to receive power from the contact wires 101a, 101b while traveling, thereby reducing the capacity of the battery module 24 while ensuring sufficient cruising range.

[0013] <Power Supply Facility> FIG. 2 is a diagram showing an example of a power supply lane L1 set on a motorway or the like, and FIG. 3 is a diagram showing an electric vehicle 10 and a power supply facility 100 as viewed from the direction of arrow III in FIG.

[0014] As shown in Fig. 2, three travel lanes La, Lb, and Lc are installed on the expressway. As shown by hatching in Fig. 2, a power supply lane L1 equipped with contact wires 101a and 101b is installed over a predetermined distance in travel lane La. As shown in the enlarged portion, an overhead pole 102 for suspending the contact wires 101a and 101b is installed on the side of the road of power supply lane L1.

[0015] As shown in Fig. 3, the overhead pole 102 constituting the power supply facility 100 has a bracket 104a supporting a positive-side suspension wire 103a and a bracket 104b supporting a negative-side suspension wire 103b. A positive-side contact wire 101a is suspended from the suspension wire 103a via a hanger 105a, and a negative-side contact wire 101b is suspended from the suspension wire 103b via a hanger 105b. A commercial power supply (external power supply) 107 is connected to the contact wires 101a and 101b via a power supply device 106. The power supply device 106 incorporates an AC / DC converter 108 and other components, and converts AC power from the commercial power supply 107 into DC power and supplies it to the contact wires 101a and 101b.

[0016] <Vehicle Configuration> Fig. 4 is a diagram showing an example of an electric vehicle 10 and a control system 60. As described above, the battery pack 23 is connected to the traction motor 11 via the inverter 21. Furthermore, a current collection unit 28 is connected to the current supply line 22 connecting the battery pack 23 and the inverter 21 via a charger 26, which is a power conversion device. The battery pack 23 is provided with a battery module 24 consisting of a plurality of battery cells, and a battery control unit 32 that monitors the charging and discharging of the battery module 24. Furthermore, the battery pack 23 is provided with a battery sensor 33 that detects charging and discharging currents, terminal voltages, etc. The battery control unit 32, which is an electronic control unit, has the function of calculating the SOC (State of Charge) of the battery module 24 based on the charging and discharging currents, terminal voltages, etc. detected by the battery sensor 33.

[0017] A motor control unit 34, which is an electronic control unit, is connected to the inverter 21, which converts DC power into AC power and vice versa. The motor control unit 34 controls the inverter 21, which is made up of a plurality of switching elements and the like, to control the energization state of the traction motor 11 and thereby control the motor torque (powering torque, regenerative torque). When the traction motor 11 is controlled to be in a powering state, power is supplied from the battery module 24 to the stator 11a via the inverter 21. On the other hand, when the traction motor 11 is controlled to be in a regenerative state, i.e., a power generating state, power is supplied from the stator 11a to the battery module 24 via the inverter 21.

[0018] A power supply control unit 35, which is an electronic control unit, is connected to the charger 26 and the current collecting unit 28. The power supply control unit 35 controls the current collecting unit 28 to control the raising and lowering of the pantographs 30a, 30b. The power supply control unit 35 also controls the charger 26, which is composed of a DC / DC converter or the like, to step down the DC power received from the contact wires 101a, 101b and supply the power to the battery module 24. In addition to supplying power from the charger 26 to the battery module 24, the charger 26 can also supply power to the traction motor 11 via the inverter 21.

[0019] The electric vehicle 10 has a brake device (friction brake) 41 that brakes the front wheels 40 and the rear wheels 16. The brake device 41 has a master cylinder 43 that outputs brake fluid pressure in conjunction with a brake pedal 42, calipers 45 that brake disc rotors 44 of the front wheels 40 and the rear wheels 16, and a brake actuator 46 that adjusts the brake fluid pressure of each caliper 45. The brake actuator 46 has an electric pump, an accumulator, an electromagnetic valve, etc. (not shown) for adjusting the brake fluid pressure. In addition, a brake control unit 47, which is an electronic control unit, is connected to the brake actuator 46.

[0020] The electric vehicle 10 has a front camera 50 that captures images ahead of the vehicle and a front radar 51 that detects the distance to an object located ahead of the vehicle. A driving control unit 52, which is an electronic control unit, is connected to the front camera 50 and the front radar 51. The driving control unit 52 controls the traction motor 11, the brake actuator 46, etc. based on image data from the front camera 50 and distance data from the front radar 51, and performs automatic driving control in the power supply lane L1, etc. The automatic driving control performed by the driving control unit 52 also includes driving assistance control that automatically performs some of the driving operations. Examples of driving assistance control include adaptive cruise control, which accelerates and decelerates while following a preceding vehicle, lane keeping control, which steers the wheels to prevent the vehicle from deviating from the driving lane, and automatic braking control, which brakes the wheels when the vehicle approaches another vehicle, etc.

[0021] <Control System> The electric vehicle 10 has a control system 60 consisting of multiple electronic control units to control the electric axle 13, the charger 26, the brake device 41, etc. The electronic control units that make up the control system 60 include the battery control unit 32, the motor control unit 34, the power supply control unit 35, the brake control unit 47, and the driving control unit 52 described above. Another electronic control unit that makes up the control system 60 is an integrated control unit 61 that outputs control signals to the control units 32, 34, 35, 47, and 52. These control units 32, 34, 35, 47, 52, and 61 are connected to each other so as to be able to communicate with each other via a communication network 62 such as a Controller Area Network (CAN). The integrated control unit 61 sets operation targets for the electric axle 13, the charger 26, the brake device 41, etc. based on input data from the various control units 32, 34, 35, 47, and 52 and various sensors described below. Then, the control circuit generates control signals according to operation targets of the electric axle 13 , the charger 26 , the brake device 41 , etc., and outputs these control signals to the various control units 32 , 34 , 35 , 47 , 52 .

[0022] Sensors connected to the integrated control unit 61 include an accelerator sensor 63 that detects the operation status of the accelerator pedal and a brake sensor 64 that detects the operation status of the brake pedal 42. Sensors connected to the integrated control unit 61 also include a vehicle speed sensor 65 that detects the vehicle speed, which is the traveling speed of the electric vehicle 10, and a gradient sensor 66 that detects the gradient of the road surface on which the vehicle is traveling. A start switch 67 that is manually operated when starting up the control system 60 is also connected to the integrated control unit 61.

[0023] FIG. 5 is a diagram showing an example of the basic structure of the control units 32, 34, 35, 47, 52, and 61. As shown in FIG. 5, the control units 32, 34, 35, 47, 52, and 61, which are electronic control units, have a microcontroller 72 incorporating a processor 70 and a main memory (memory) 71. A predetermined program is stored in the main memory 71, and the program is executed by the processor 70. The processor 70 and the main memory 71 are connected to each other so that they can communicate with each other. Note that multiple processors 70 may be incorporated into the microcontroller 72, and multiple main memories 71 may be incorporated into the microcontroller 72.

[0024] The control units 32, 34, 35, 47, 52, and 61 each include an input circuit 73, a drive circuit 74, a communication circuit 75, an external memory 76, and a power supply circuit 77. The input circuit 73 converts signals input from various sensors into signals that can be input to the microcontroller 72. The drive circuit 74 generates drive signals for various devices, such as the inverter 21 and the charger 26, based on signals output from the microcontroller 72. The communication circuit 75 converts signals output from the microcontroller 72 into communication signals directed to other control units. The communication circuit 75 also converts communication signals received from other control units into signals that can be input to the microcontroller 72. The power supply circuit 77 supplies a stable power supply voltage to the microcontroller 72, the input circuit 73, the drive circuit 74, the communication circuit 75, the external memory 76, and the like. The external memory 76, which may be a nonvolatile memory, stores programs and various data.

[0025] <Mode Switching Control: Flowchart> Next, a description will be given of mode switching control for switching the driving mode of the electric vehicle 10. Fig. 6 is a flowchart showing an example of the execution procedure of the mode switching control. Each step of the mode switching control shown in Fig. 6 is executed by the processor 70 constituting the control system 60. Furthermore, the mode switching control shown in Fig. 6 is control that is executed by the control system 60 at predetermined intervals after the control system 60 is started by operating the start switch.

[0026] The electric vehicle 10 has two running modes: a normal running mode (first running mode) that is executed when power is not being supplied from the contact wires 101 a, 101 b, and a power-supply running mode (second running mode) that is executed when power is being supplied from the contact wires 101 a, 101 b. The normal running mode of the electric vehicle 10 is a running mode in which regenerative braking of the traction motor 11 is permitted, and the power-supply running mode of the electric vehicle 10 is a running mode in which regenerative braking of the traction motor 11 is prohibited. In other words, the power-supply running mode is a running mode in which regenerative power during vehicle braking is controlled to zero, and is a running mode in which regenerative power during vehicle braking is smaller than that in the normal running mode.

[0027] 5, the control system 60 proceeds to step S10 and executes a normal driving mode in which regenerative braking of the traction motor 11 is permitted. Next, the control system 60 proceeds to step S11 and determines whether a predetermined power supply start condition is met. Here, the power supply start condition is a condition for starting power supply from the contact wires 101a, 101b to the electric vehicle 10. For example, the power supply start condition may be that the electric vehicle 10 is traveling in the power supply lane L1 and that the SOC of the battery module 24 is below a predetermined threshold.

[0028] If the control system 60 determines in step S11 that the power supply start condition is met, the process proceeds to step S12, where it executes a power supply running mode that prohibits regenerative braking of the traction motor 11. The control system 60 also proceeds to step S13, where it raises the pantographs 30a, 30b to activate the charger 26, thereby starting to take in power (hereinafter referred to as power supply) supplied to the electric vehicle 10 from the contact wires 101a, 101b. In the power supply running mode, the control system 60 also controls the traction motor 11 and the brake device 41, thereby controlling the speed of the electric vehicle 10 to maintain a predetermined target vehicle speed.

[0029] Next, the control system 60 proceeds to step S14 and determines whether a predetermined power supply stop condition is satisfied. Here, the power supply stop condition is a condition for stopping the power supply from the trolley wires 101a, 101b to the electric vehicle 10. Examples of the power supply stop condition include the electric vehicle 10 not traveling in the power supply lane L1 and the SOC of the battery module 24 exceeding a predetermined threshold.

[0030] If the control system 60 determines in step S14 that the power supply stop condition is not met, the process proceeds to step S12 to continue the power supply running mode, and to step S13 to continue taking in the supplied power. On the other hand, if the control system 60 determines in step S14 that the power supply stop condition is met, the process proceeds to step S15 to stop the charger 26 and lower the pantographs 30a, 30b to stop taking in the supplied power. In addition, the control system 60 proceeds to step S16 to execute the normal running mode in which regenerative braking of the traction motor 11 is permitted.

[0031] <Mode Switching Control: Timing Chart> Figure 7 is a timing chart showing an example of the operating status of various devices during mode switching control. Fig. 7 also shows a situation in which the electric vehicle 10 maintains a constant vehicle speed. As shown at time t1 in Fig. 7 , in normal running mode in which no supplied power is being taken in (symbol a1), if the road surface being traveled is on an uphill slope (symbol b1), the traction motor 11 is controlled to a powering state (symbol c1). Furthermore, as shown at time t2, in normal running mode in which no supplied power is being taken in (symbol a2), if the road surface being traveled is on a downhill slope (symbol b2), the traction motor 11 is controlled to a regenerative state (symbol c2).

[0032] Thereafter, as shown at time t3, when the electric vehicle 10 enters the power supply lane L1 and the power supply start condition is satisfied, the traveling mode is switched from the normal traveling mode to the power supply traveling mode (symbol a3), and the charger 26 is operated to increase the supplied power to a predetermined target power P1 (symbol d1). Furthermore, as shown at time t4, in the power supply traveling mode in which supplied power is taken in (symbol a4), if the traveling road surface is on an uphill slope (symbol b3), the traction motor 11 is controlled to a powering state (symbol c3). Furthermore, as shown at time t5, in the power supply traveling mode in which supplied power is taken in (symbol a5), if the traveling road surface is on a downhill slope (symbol b4), the braking force of the brake device 41 is increased without controlling the traction motor 11 to a regenerative state (symbols c4, e1).

[0033] As shown at time t5 in Figure 7, in the power supply traveling mode in which supplied power is taken in, when traveling down a slope while maintaining a target vehicle speed, it is necessary to brake the electric vehicle 10 to suppress an increase in vehicle speed. Here, as described above, when traveling down a slope in the power supply traveling mode, the control system 60 increases the braking force of the brake device 41 without controlling the traction motor 11 to a regenerative state. In other words, when braking the vehicle in the power supply traveling mode, the control system 60 activates the brake device 41 without regenerative braking the traction motor 11. In this way, by limiting the regenerative power of the traction motor 11, it is possible to increase the efficiency of power supply from the contact wires 101a, 101b to the electric vehicle 10.

[0034] That is, as shown by dashed line x1 in Figure 7, when the traction motor 11 is subjected to regenerative braking during vehicle braking in the power supply traveling mode, not only is feed power supplied to the battery module 24, but regenerative power is also supplied to the battery module 24. At this time, depending on the output characteristics of the battery module 24, the regenerative power may not be able to be taken in by the battery module 24, and the feed power may be cut off, as shown by dashed line x2. As such, a cutoff of the feed power is a factor that reduces power supply efficiency, so by limiting the regenerative braking of the traction motor 11, the supply of feed power is maintained and power supply efficiency is increased.

[0035] In the above description, regenerative braking of the traction motor 11 is prohibited when braking the vehicle in the power supply traveling mode, but this is not limited to this. For example, as shown by the two-dot chain line x3 in Fig. 7 , the traction motor 11 may be regeneratively braked to the extent that it does not affect the supply power taken in by the battery module 24. In this way, even when regenerative braking is permitted in the power supply traveling mode, the regenerative power generated in the power supply traveling mode will be smaller than the regenerative power generated in the normal traveling mode, provided that the target braking force of the electric vehicle 10 is the same.

[0036] <Power-supplied traveling mode> In the above description, the control system 60 that executes the power-supplied traveling mode controls the traction motor 11 and the brake device 41 to maintain the target vehicle speed, but this is not limited to this. For example, as shown in Fig. 1 , when a leading vehicle 110 is present, the control system 60 controls the traction motor 11 and the brake device 41 to maintain a constant inter-vehicle distance D1 from the leading vehicle 110. This makes it possible to avoid excessive deceleration of the electric vehicle 10 even when the leading vehicle 110 suddenly decelerates, thereby preventing regenerative braking of the traction motor 11 and improving power supply efficiency.

[0037] FIG. 8 is a diagram illustrating an example of a driving situation of the electric vehicle 10. As shown in FIG. 8, the power supply lane L1 may be curved. In this case, the control system 60 may determine the curvature of the power supply lane L1 based on image data from the front camera 50 and control the brake device 41 based on the curvature of the power supply lane L1. For example, if the control system 60 determines that the curvature of the power supply lane L1 located in front of the vehicle is large, the control system 60 activates the brake device 41 in advance to reduce the vehicle speed. In this way, by feedforward controlling the brake device 41, excessive deceleration of the electric vehicle 10 can be avoided even when the electric vehicle 10 transitions from straight-ahead driving to cornering driving. This prevents regenerative braking of the traction motor 11 and improves power supply efficiency.

[0038] The control system 60 may determine the gradient of the road surface ahead of the vehicle based on image data from the front camera 50, and control the brake device 41 based on the determined gradient of the road surface. For example, if the control system 60 determines that the power supply lane L1 located ahead of the vehicle has a steep downward gradient, it activates the brake device 41 in advance to reduce the vehicle speed. By feedforward controlling the brake device 41 in this way, excessive deceleration of the electric vehicle 10 can be avoided even when the electric vehicle 10 moves down a gradient, and therefore regenerative braking of the traction motor 11 can be prevented, thereby improving power supply efficiency.

[0039] The control system 60 controls a steering motor provided in a steering mechanism (not shown) so that the electric vehicle 10 travels approximately in the center of the power supply lane L1. This makes it possible to appropriately maintain the contact state between the pantographs 30a, 30b and the trolley wires 101a, 101b, thereby improving power supply efficiency. Furthermore, when the control system 60 detects an obstacle 120 ahead of the vehicle, it activates the brake device 41 in advance to reduce the vehicle speed. In this way, by feedforward controlling the brake device 41, excessive deceleration of the electric vehicle 10 can be avoided even when the electric vehicle 10 avoids the obstacle 120, thereby preventing regenerative braking of the traction motor 11 and improving power supply efficiency.

[0040] Second Embodiment In the example shown in Fig. 1, an electric vehicle is used as the electric vehicle 10, but the present invention is not limited to this, and a hybrid vehicle may be used as the electric vehicle 80. Fig. 9 is a diagram showing an example of the configuration of an electric vehicle 80 according to another embodiment of the present disclosure. Note that in Fig. 9, parts that are the same as those shown in Fig. 1 are given the same reference numerals, and descriptions thereof will be omitted.

[0041] As shown in Figure 9, an electric vehicle 80, which is a hybrid vehicle, has a power unit 83 consisting of an engine 81 and a transmission 82. A traction motor 84 is incorporated in the transmission 82, and a clutch 85 is provided between the engine 81 and the traction motor 84. Furthermore, an output shaft 86 of the transmission 82 is connected to the rear wheels 16 via a propeller shaft 87, a differential 88, and an axle 89. In this way, the engine 81 is connected to the rear wheels (wheels) 16, and the traction motor (electric motor) 84 is connected to the rear wheels 16.

[0042] An inverter 21 is connected to the traction motor 84 via a current line 20, and a battery pack 23 is connected to the inverter 21 via a current line 22. A charger 26 is connected to the current line 22 via a current line 25, and a current collection unit 28 is connected to the charger 26 via a current line 27. In this way, a battery module (power storage body) 24 is connected to the traction motor 84, and the charger 26 is connected to the current collection unit (power receiving unit) 28 and the battery module 24.

[0043] An engine control unit 90, which constitutes part of the control system 60, is connected to the engine 81 of the power unit 83. The engine control unit 90, which is an electronic control unit, outputs control signals to a throttle valve, an injector, an ignition coil, and the like (not shown), and controls engine torque on the acceleration or deceleration side. That is, the engine control unit 90 can control engine torque on the deceleration side, i.e., engine braking, by controlling the throttle valve to the closing side or by cutting off fuel injection from the injector.

[0044] <Mode Switching Control: Timing Chart> Fig. 10 is a timing chart showing an example of the operating status of various devices during mode switching control. Similar to Fig. 7, Fig. 10 shows a situation in which electric vehicle 80 maintains a constant vehicle speed.

[0045] 10 , in a normal traveling mode in which no power supply is taken in (symbol a1), if the traveling road surface is on an upslope (symbol b1), the traction motor 84 is controlled to a powering state (symbol c1). Also, in a normal traveling mode in which no power supply is taken in (symbol a2), if the traveling road surface is on a downslope (symbol b2), the traction motor 84 is controlled to a regenerative state (symbol c2). In the normal traveling mode, if the SOC of the battery module 24 exceeds a predetermined lower limit, the engine 81 is kept stopped in order to improve fuel economy.

[0046] Furthermore, as shown at time t3, when the electric vehicle 80 enters the power supply lane L1 and the power supply start condition is satisfied, the traveling mode is switched from the normal traveling mode to the power supply traveling mode (symbol a3), and the charger 26 is operated to increase the supplied power to a predetermined target power P1 (symbol d1). Furthermore, as shown at time t4, in the power supply traveling mode in which supplied power is taken in (symbol a4), if the traveling road surface is on an uphill slope (symbol b3), the engine torque is controlled to the acceleration side (symbol e1), and the motor torque of the traction motor 84 is controlled to zero (symbol c3). Furthermore, as shown at time t5, in the power supply traveling mode in which supplied power is taken in (symbol a5), if the traveling road surface is on a downhill slope (symbol b4), engine braking is generated without controlling the traction motor 84 to a regenerative state, and the braking force of the brake device 41 is increased (symbols c4, e2, f1).

[0047] As shown at time t5 in Figure 10, in the power supply traveling mode in which supplied power is taken in, when traveling down a slope while maintaining a target vehicle speed, it is necessary to brake the electric vehicle 80 to suppress an increase in vehicle speed. Here, as described above, when traveling down a slope in the power supply traveling mode, the control system 60 generates engine braking and increases the braking force of the brake device 41 without controlling the traction motor 84 to a regenerative state. In other words, when braking the vehicle in the power supply traveling mode, the control system 60 activates the engine brake and the brake device 41 without regenerative braking the traction motor 84. In this way, by limiting the regenerative power of the traction motor 84 when braking the vehicle, it is possible to increase the efficiency of power supply from the contact wires 101a, 101b to the electric vehicle 80, as in the electric vehicle 10 described above.

[0048] Furthermore, as shown at time t4, in the power supply traveling mode in which supplied power is taken in, when traveling up a slope while maintaining the target vehicle speed, it is necessary to accelerate the electric vehicle 80 to prevent a decrease in vehicle speed. Here, as described above, when traveling up a slope in the power supply traveling mode, the control system 60 generates engine torque for acceleration without controlling the traction motor 84 to a powering state. In this way, by controlling the motor torque of the traction motor 84 to zero, it is possible to controllably disconnect the traction motor 84 from the battery module 24 and the charger 26, and from this point of view as well, it is possible to improve the efficiency of power supply from the trolley wires 101a, 101b to the electric vehicle 80.

[0049] In the example shown in FIG. 10 , regenerative braking of the traction motor 84 is prohibited when braking the vehicle in the power supply traveling mode, but this is not limited to this. For example, the traction motor 84 may be regeneratively braked to the extent that it does not affect the supply power taken in by the battery module 24. Even when regenerative braking is permitted in the power supply traveling mode in this way, under the condition that the target braking force of the electric vehicle 80 is the same, the regenerative power generated in the power supply traveling mode will be smaller than the regenerative power generated in the normal traveling mode. In addition, in the example shown in FIG. 10 , the motor torque of the traction motor 84 is controlled to zero when the vehicle accelerates in the power supply traveling mode, but this is not limited to this. For example, the traction motor 84 may be controlled to a power running state when the vehicle accelerates in the power supply traveling mode.

[0050] Other Embodiments The present disclosure is not limited to the above-described embodiment and may be modified in various ways without departing from the spirit and scope of the present disclosure. For example, in the above description, the control system 60 is configured with six control units 32, 34, 35, 47, 52, and 61, but this is not limiting. For example, the control system 60 may be configured with one control unit or multiple control units. Furthermore, while the illustrated electric vehicles 10 and 80 are rear-wheel drive electric vehicles, this is not limiting and the electric vehicles may be front-wheel drive electric vehicles or all-wheel drive electric vehicles. Furthermore, while the illustrated electric vehicle 80 is a parallel hybrid vehicle, this is not limiting and the electric vehicle may be a series hybrid vehicle or a series-parallel hybrid vehicle.

[0051] In the above description, the trolley wires 101a, 101b are arranged above the vehicle, but this is not limited thereto. The trolley wires may be arranged on the side of the vehicle or below the vehicle. For example, if the trolley wires are installed on a guardrail or the like on the side of the vehicle, a current collecting arm extending laterally from the electric vehicle is provided, and power can be supplied while the vehicle is moving by contacting this current collecting arm with the trolley wire. Furthermore, the illustrated power supply equipment 100 is a contact-type, i.e., conductive, power supply equipment, but this is not limited thereto. A non-contact, i.e., inductive, power supply equipment may also be used. Furthermore, the illustrated electric vehicles 10, 80 receive DC power from the power supply equipment 100, but this is not limited thereto. The electric vehicles 10, 80 may also receive AC power from the power supply equipment 100.

[0052] 10...electric vehicle, 11...driving motor (electric motor), 16...rear wheel (wheel), 24...battery module (power storage body), 26...charger, 28...power collection unit (power receiving unit), 40...front wheel (wheel), 41...brake device (friction brake), 60...control system, 70...processor, 71...main memory (memory), 80...electric vehicle, 81...engine, 84...driving motor (electric motor), 107...commercial power supply (external power supply)

Claims

1. An electric vehicle that receives power from an external power source while traveling, comprising: an electric motor connected to wheels; a power storage unit connected to the electric motor; a power receiving unit that receives power from the external power source; a charger connected to the power receiving unit and the power storage unit; and a control system that has a processor and a memory communicatively connected to each other and controls the electric motor, wherein the electric vehicle has a first traveling mode and a second traveling mode in which regenerative power during vehicle braking is smaller than that in the first traveling mode, and the control system executes the first traveling mode when the charger is stopped and not being supplied with power, and executes the second traveling mode when power is being supplied for traveling and the charger is operated.

2. The electric vehicle according to claim 1, wherein the control system prohibits regenerative braking of the electric motor in the second driving mode.

3. An electric vehicle according to claim 1, further comprising a friction brake for braking a wheel, and the control system activates the friction brake when braking the vehicle in the second driving mode.

4. An electric vehicle according to claim 3, wherein the control system activates the friction brake without causing the electric motor to perform regenerative braking when braking the vehicle in the second driving mode.

5. An electric vehicle according to claim 1, further comprising an engine coupled to wheels, wherein the control system activates engine brakes when braking the vehicle in the second driving mode.

6. An electric vehicle according to claim 5, wherein the control system activates engine braking without causing the electric motor to perform regenerative braking when braking the vehicle in the second driving mode.

7. An electric vehicle as claimed in claim 1, further comprising: a friction brake for braking the wheels; and an engine connected to the wheels, wherein the control system activates the friction brake and the engine brake when braking the vehicle in the second driving mode.

8. An electric vehicle according to claim 7, wherein the control system activates the friction brake and the engine brake without causing the electric motor to perform regenerative braking during vehicle braking in the second driving mode.

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