JP5182514B2 - Control device for electric vehicle - Google Patents

Description

  The present invention relates to a control device for an electric vehicle equipped with a generator that generates electricity by driving an engine.

  In an electric vehicle equipped with a generator that generates electricity by driving the engine, normally, when starting the engine, power is supplied from the battery to the generator, and the generator is functioned as a motor for starting the engine, thereby Make a ranking. Then, after the engine is started, power is generated by the generator by driving the engine, and the electric power obtained by the power generation is stored in the battery or used as power supplied to the drive motor.

By the way, in order to start the engine by functioning the generator as a motor for starting the engine, it is necessary to supply a relatively large amount of electric power to the generator. It can be difficult. Therefore, as a countermeasure when the battery storage amount decreases, when the battery storage amount falls below a predetermined value, power is not supplied from the battery to the generator, and regenerative braking is performed while the electric vehicle is running. Sometimes, it has also been proposed to perform control such that regenerative power obtained by regenerative braking is supplied to a generator to start the engine (see, for example, Patent Document 1).
JP 11-336579 A

  However, in the conventional technique described in Patent Document 1, since the engine is stopped and power generation by the generator is not performed until regenerative braking is performed, power is supplied to the drive motor from the battery. The amount of electricity stored in the battery will be further reduced. When the time during which the regenerative braking is not performed becomes longer, there is a problem that the battery is overdischarged and the battery is deteriorated.

  The present invention was devised to solve the above-described problems of the prior art, and efficiently starts the engine in accordance with the amount of charge of the battery and effectively avoids the problem of battery overdischarge. An object of the present invention is to provide a control device for an electric vehicle that can be used.

  In order to solve the above-described problem, the control device for an electric vehicle according to the present invention includes a first threshold value and a second threshold value that is larger than the first threshold value as threshold values for the storage amount of the battery. If the amount of electricity stored in the battery falls below the second threshold when the engine is stopped, the regenerative power obtained by the regenerative braking is supplied to the generator to start the engine when the regenerative braking is performed. If the stored amount of the battery falls below the first threshold without starting the engine, the engine is started by supplying power from the battery to the generator.

  According to the control apparatus for an electric vehicle according to the present invention, when the amount of charge of the battery is between the first threshold value and the second threshold value, the regenerative braking is performed after waiting for the regenerative braking to be performed. When the engine is started by the regenerative power obtained by regenerative braking and the rechargeable brake is not performed and the engine is stopped, the stored amount of the battery falls below the first threshold value. Since the engine is started, the engine can be started efficiently with regenerative power in a state where there is a certain margin in the amount of battery charge, and the engine is recharged when the battery charge state further decreases without regenerative braking. It is possible to effectively avoid the battery from being overdischarged by charging the battery with the electric power from the generator that generates power by driving.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[Constitution]
An example of an electric vehicle to which the present invention is applied is shown in FIG. The electric vehicle shown in FIG. 1 converts electric power taken out from the battery 1 into power by a drive motor 2 and converts the power by a differential speed reducer 3 as necessary to drive the drive wheels 4. This is a generator-mounted electric vehicle having a configuration in which a generator 6 that generates power by driving an engine 5 is added to a traveling electric vehicle mainly for the purpose of extending a cruising distance.

  In this electric vehicle, a drive inverter 7 is connected to the drive motor 2, and electric power converted into alternating current of a predetermined voltage and a predetermined frequency is supplied to the drive motor 2 by the drive inverter 7, thereby Travel is controlled. When the electric vehicle is braked, the regenerative power generated by the drive motor 2 is converted into direct current by the drive inverter 7 and supplied to the battery 1 or the generator 6. Hereinafter, the combination of the drive motor 2 and the drive inverter 7 is referred to as a drive device D.

  In addition, a generator inverter 8 is connected to the generator 6, and the electric power of the generator 6 generated by driving the engine 5 is converted into direct current by the generator inverter 8 and supplied to the battery 1 or the driving device D. Further, when the engine 5 is started, the power from the battery 1 or the regenerative power from the driving device D is converted into alternating current by the power generation inverter 8 and supplied to the power generator 6, so that the power generator 6 is used for starting the engine. The engine 5 is cranked. Hereinafter, a combination of the engine 5, the generator 6, and the power generation inverter 8 is referred to as a power generation device G. The electric auxiliary machine 9 in FIG. 1 is a general term for various electric load devices such as an air conditioner and a car navigation system mounted on an electric vehicle.

  The operation of the electric vehicle configured as described above is controlled by the control device 10 including the battery controller 11, the drive system controller 12, and the power generation system controller 13. In the present embodiment, the present invention is implemented as one of the control functions of the control device 10. In the following description, a case where individual hardware (for example, a microcomputer chip) is used for each of the battery controller 11, the drive system controller 12, and the power generation system controller 13 constituting the control device 10 will be described. The specific hardware configuration is arbitrary, and various changes are possible, such as configuration with a single piece of hardware or realization as a function of another controller.

  The battery controller 11 acquires parameters of the battery 1 such as terminal voltage, energization current, temperature, internal resistance, and storage amount by measurement or estimation. Then, using the acquired parameters, it is determined whether or not power generation by the power generation device D is necessary, and the request is sent to the power generation system controller 13. In addition, the battery controller 11 calculates the allowable power range of the battery 1 using the acquired parameters, and sends it to the drive system controller 12 and the power generation system controller 13.

  The drive system controller 12 controls the drive device D so that the drive force according to the accelerator operation by the driver of the electric vehicle is transmitted to the drive wheels 4. The power generation system controller 13 controls the power generation device G so that the engine 5 and the power generator 6 are stopped during non-power generation, and so that the engine 5 and the power generator 6 operate in an efficient region during power generation. Furthermore, the drive system controller 12 and the power generation system controller 13 operate in a coordinated manner so that the input / output power of the battery 1 is within the permitted power range determined by the internal state of the battery 1. That is, the power generation by the power generation device G is controlled so that the amount of power stored in the battery 1 is maintained in an appropriate range in relation to the power consumed by the drive device D.

[Operation of power generator]
Next, in the electric vehicle configured as described above, the operation of the power generation device G when transitioning from the non-power generation state to the power generation state will be described with reference to FIG. 2A to 2C each take a common time T on the horizontal axis, and T1 is a timing at which a power generation request is input from the power generation system controller 13 of the control device 10 to the engine 5 and the power generation inverter 8. , T2 represents the timing when the rotational speed of the engine 5 reaches the target rotational speed, and T3 represents the timing when the torque of the engine 5 reaches the target torque. Also, the vertical axis in FIG. 2A represents the torque of the engine 5, the vertical axis in FIG. 2B represents the rotation speed of the engine 5, and the vertical axis in FIG. .

  In the section of T0 ≦ T ≦ T1, the power generation device G is in a non-power generation state, and the engine 5 is not combusting and is not rotating. Further, the generator 6 is also stopped, and no power is transferred.

  In the section of T1 ≦ T ≦ T2, since the power generation device G transitions to the power generation state in response to the power generation request, first, the torque and the rotation speed of the engine 5 at which the power generation device G can operate in an efficient region are set to the target torque. And set as the target speed. Next, the generator 6 is controlled by the generator inverter 8 so that the engine 5 reaches the target rotational speed. That is, in this section, the generator 6 cranks the engine 5, and the engine 5 does not burn until reaching the target rotational speed, so the friction torque increases as the rotational speed increases. The generator 6 consumes electric power to overcome the friction torque and increase the rotational speed of the engine 5.

  In the section of T2 ≦ T ≦ T3, since the rotational speed of the engine 5 has reached the target rotational speed, combustion is started and the torque of the engine 5 increases until it reaches the target torque. In order to maintain the predetermined number of revolutions, the generator 6 shifts from a state in which power is consumed to a state in which power is generated as the torque of the engine 5 increases.

  In the section of T ≧ T3, the torque and the rotational speed of the engine 5 reach the target torque and the target rotational speed, respectively, and the generator 6 generates electric power according to the output of the engine 5.

  As can be seen from the operation example of the power generation device G described above, the power generation device G once consumes electric power with the start of the engine 5 when transitioning from the non-power generation state to the power generation state in response to a power generation request, and then the engine When 5 is activated, the generator 6 generates power and supplies power. Here, the power consumed by the power generation device G at the start of power generation can be covered by the power extracted from the battery 1, but the period during which the power generation device G is consuming power, that is, T1 ≦ T ≦ T2 in FIG. If the drive device D is in the regenerative state in the section, the regenerative power from the drive device D can be used.

  In the present invention, when power generation by the power generation device G is started, the charge / discharge loss of the battery 1 is smaller when the power consumed by the power generation device G is supplied from the regenerating drive device D than from the battery 1. Focusing on the fact that it is possible and efficient, the energy efficiency of the vehicle system can be increased by controlling the regenerative power to be supplied as much as possible. However, since the timing at which regenerative power is obtained from the drive device D depends on the behavior of the electric vehicle, if the power generation by the power generation device G is not started without performing regenerative braking for a long time, the power consumption by the drive device D As a result, the amount of electricity stored in the battery 1 is further reduced to an overdischarged state, and the battery 1 may be deteriorated. Therefore, in the present invention, by optimizing the control at the time of starting power generation by the power generation device 5, it is possible to realize an energy efficient vehicle system while effectively avoiding the problem of overdischarge of the battery 1. ing. Hereinafter, a specific control example (example) by the control device 10 to which the present invention is applied will be described in more detail.

[First embodiment]
FIG. 3 is a flowchart showing an example (first embodiment) of control by the control device 10 to which the present invention is applied. A feature of the control of the present embodiment is that the power generation apparatus G uses the first threshold Th1 and the second threshold Th2 that is larger than the first threshold Th1 as the threshold for the stored amount of the battery 1. If the amount of electricity stored in the battery 1 decreases to be below the second threshold Th2 in the non-power generation state, regenerative power is supplied from the drive device D to the generator 6 when regenerative braking is performed, and the engine 5 And the regenerative braking is not performed, and when the amount of power stored in the battery 1 is further reduced below the first threshold Th1 while the power generation device G remains in the non-power generation state, the electric power extracted from the battery 1 is converted into the generator. 6 and the cranking of the engine 5 is performed.

  When the flow of FIG. 3 is started, the control device 10 first confirms whether or not the power generation device G is in an operating state in step S101. If the power generation device G is in an operating state, surplus power that is not consumed by the drive device D among the power generated by the generator 6 is stored in the battery 1, so that the storage amount of the battery 1 gradually increases with time. It tends to rise. Here, if the amount of electricity stored in the battery 1 is too large, the battery 1 is overcharged and the battery 1 is deteriorated. Therefore, when the amount of electricity stored in the battery 1 increases to some extent, the operation of the power generator G is stopped.

  That is, when the power generation device G is in the operating state, the control device 10 acquires the state of charge (SOC) of the battery 1 in step S102, and in step S103, the amount of storage of the battery 1 is the upper limit threshold value. It is determined whether or not Th0 has been reached. Then, while the amount of electricity stored in the battery 1 is lower than the upper limit threshold Th0, the processes of step S102 and step S103 are periodically repeated. When the amount of electricity stored in the battery 1 reaches the upper limit threshold Th0, in step S104, the power generator G Stop operation. The upper limit threshold Th0 is a value that can prevent the battery 1 from being overcharged if the operation of the power generation device G is stopped when the stored amount of the battery 1 reaches the upper limit threshold Th0. It is set to an optimum value obtained through an experiment or the like (for example, 70 to 90% when the charged amount of the battery 1 at full charge is 100% and the charged amount of the battery 1 at full discharge is 0%).

  On the other hand, if the power generation device G is in the non-operating state, all the electric power consumed by the driving device D is taken out from the battery 1, and therefore the amount of electricity stored in the battery 1 tends to gradually decrease with time. Here, if the amount of electricity stored in the battery 1 becomes too small, the battery 1 is overdischarged and the battery 1 is deteriorated. Therefore, when the amount of electricity stored in the battery 1 decreases to some extent, the engine 5 is started and power generation by the generator 6 is started. Let At this time, energy efficiency is improved by performing control so that regenerative power can be used as much as possible as power necessary for starting the engine 5.

  That is, when the power generation device G is in the non-operating state, the control device 10 acquires the stored amount (SOC) of the battery 1 in step S105, and in step S106, the stored amount of the battery 1 is equal to the second threshold Th2. Judge whether or not Then, the process of step S105 and step S106 is periodically repeated while the charged amount of the battery 1 is greater than or equal to the second threshold Th2, and the process proceeds to step S107 when the charged amount of the battery 1 falls below the second threshold Th2. .

  When the charged amount of the battery 1 falls below the second threshold Th2, the control device 10 determines whether or not the charged amount of the battery 1 has fallen below the first threshold Th1 in step S107. In step S108, it is monitored whether or not regenerative braking has been performed while the amount of stored power is not less than the first threshold value Th1. If regenerative braking is performed before the stored amount of the battery 1 falls below the first threshold Th1, regenerative power obtained by regenerative braking is supplied to the electric motor 6 in step S109, and the electric motor 6 cranks the engine 5. And the power generator G is operated.

  On the other hand, after the storage amount of the battery 1 falls below the second threshold Th2, if the storage amount of the battery 1 further falls below the first threshold Th1 without performing regenerative braking, the battery 1 starts from the battery 1 in step S110. Is supplied to the generator 6, the engine 6 is cranked by the motor 6, and the power generator G is operated.

  The first threshold value Th1 for the amount of electricity stored in the battery 1 is a value that can start the engine 5 with the electric power from the battery 1 without causing overdischarge of the battery 1, that is, the amount of electricity stored in the battery 1 is the first. If the engine 5 is started with the electric power of the battery 1 immediately after the threshold value Th1 is exceeded, the battery 1 can be prevented from being overdischarged, and the optimum value obtained through a prior experiment or the like (for example, at the time of full charge) 10 to 30% when the charged amount of the battery 1 is 100% and the charged amount of the battery 1 at the time of full discharge is 0%). In addition, the second threshold Th2 with respect to the amount of power stored in the battery 1 is set to a value that is, for example, about 5 to 10% larger than the first threshold Th1.

  FIG. 4 shows that while the power generation device G is in an inoperative state and the amount of power stored in the battery 1 gradually decreases with time, the amount of charge of the battery 1 varies between the first threshold Th1 and the second threshold Th2. In a scene where regenerative braking is performed when the control device 10 is in between, the input / output power of the drive device D, the power generation device G, and the battery 1 when the control device 10 performs control according to the flow of FIG. The specific example of the mode of the time change of charge amount is shown. 4A and 4B each take a common time T on the horizontal axis, T11 is a timing at which it is determined that the charged amount of the battery 1 falls below the second threshold Th2, and T12 is the regenerative power. The timing when the start of the power generation device G (engine start) is started and T13 indicates the timing when the start of the power generation device G is completed and the state is changed to the power generation state. 4A indicates the input / output power of the drive device D, the power generation device G, and the battery 1, and the vertical axis of FIG.

  In FIG. 4A, the thick line graph shows the time change of the input / output power of the driving device D. The power is increased as the distance from the center line becomes 0, and the power line power is increased downward. This means that the regenerative power increases as the distance increases. For example, the electric vehicle mainly shifts upward during acceleration and downward during deceleration. Moreover, in FIG. 4A, the thin line graph shows the time change of the input / output power of the power generation apparatus G. The power consumption increases as the distance from the center line becomes 0 with the center line as the power, It shows that the power supply increases as it goes away. For example, the engine 5 mainly shifts upward during start-up with cranking and downward during steady power generation operation. Also, in FIG. 4A, the broken line graph shows the time change of the input / output power of the battery 1, with the central line as power 0, the discharge power increases as the distance from the line increases, and the lower line This indicates that the charging power increases as the distance from the distance increases. For example, when the storage amount increases, it moves upward, and when it decreases, it moves downward.

  In the section of T10 ≦ T ≦ T11, the power generation device G is stopped, and the amount of power stored in the battery 1 is larger than the second threshold Th2, so the power generation device G is not started (engine start). This state is a state where step S105 and step S106 are looped in the flow of FIG.

  In the section of T11 ≦ T ≦ T12, the amount of power stored in the battery 1 is below the second threshold Th2, but since regenerative braking is not performed, the power generator G is not started (engine start). This state is a state in which step S107 and step S108 are looped in the flow of FIG.

  In the section of T12 ≦ T ≦ T13, the amount of power stored in the battery 1 is less than the second threshold Th2 and regenerative braking is performed. Therefore, the regenerative power from the driving device D is supplied to the generator 6 to generate power. The engine 5 is cranked by the machine 6 and the power generation apparatus G is started. This state is a state where the process of step S109 is performed in the flow of FIG. Thus, since the electric power consumed at the time of starting of the electric power generating apparatus G is supplied from the drive apparatus D in regeneration, there is no loss accompanying the discharge in the battery 1, and energy efficiency is improved.

  In the section of T ≧ T13, the start-up of the power generator G is completed, and the power generator G supplies power. This state is a state in which step S102 and step S103 are looped in the flow of FIG.

  As described above, in this embodiment, the control device 10 performs the control according to the flow of FIG. 3, so that the power generation device G can be started while maintaining the charged amount of the battery 1 within a range where the battery 1 does not deteriorate. It is possible to supply as much necessary power as possible from the regenerating drive device D to reduce the charge / discharge loss of the battery 1 and to improve the energy efficiency of the vehicle system.

[Second Embodiment]
FIG. 5 is a flowchart showing another example (second embodiment) of control by the control device 10 to which the present invention is applied. The control feature of the present embodiment is that when the power generation device G is in a non-power generation state and the amount of power stored in the battery 1 decreases to fall below the second threshold Th2 and regenerative braking is performed, the drive device D changes the power generator. Instead of supplying regenerative power immediately to 6, the regenerative power is once increased and then waited for a decrease, and then the regenerative power is supplied to the generator 6 to crank the engine 5. is there.

  When the flow of FIG. 5 is started, the control device 10 first confirms whether or not the power generation device G is in an operating state in step S201. Here, if the power generator G is in an operating state, the storage amount (SOC) of the battery 1 is acquired in step S202, and in step S203, it is determined whether or not the storage amount of the battery 1 has reached the upper limit threshold Th0. To do. Then, while the stored amount of the battery 1 is lower than the upper limit threshold Th0, the processes of step S202 and step S203 are periodically repeated. When the stored amount of the battery 1 reaches the upper limit threshold Th0, in step S204, the power generator G Stop operation.

  On the other hand, when the power generation device G is in a non-power generation state, the control device 10 acquires the amount of charge (SOC) of the battery 1 in step S205, and in step S206, the amount of charge of the battery 1 is the second threshold Th2. Judge whether or not Then, the process of step S205 and step S206 is periodically repeated while the charged amount of the battery 1 is greater than or equal to the second threshold Th2, and the process proceeds to step S207 when the charged amount of the battery 1 falls below the second threshold Th2. .

  When the charged amount of the battery 1 falls below the second threshold Th2, the control device 10 determines in step S207 whether or not the charged amount of the battery 1 has fallen below the first threshold Th1. In step S208, it is monitored whether or not regenerative braking has been performed while the amount of stored power is not less than the first threshold value Th1. If regenerative braking is performed before the stored amount of the battery 1 falls below the first threshold Th1, it is determined in step S209 whether or not the regenerative power obtained by regenerative braking is in a reduced state. When the reduction state is reached, in step S210, regenerative electric power is supplied to the electric motor 6, the engine 5 is cranked by the electric motor 6, and the power generator G is operated.

  On the other hand, when the amount of power stored in the battery 1 is reduced to be lower than the first threshold value Th1 without performing regenerative braking, the control device 10 supplies the electric power from the battery 1 to the generator 6 in step S211. The engine 5 is cranked by this, and the power generator G is operated.

  FIG. 6 shows that while the power generation device G is in an inoperative state and the storage amount of the battery 1 gradually decreases with the passage of time, the charge amount of the battery 1 becomes the first threshold value Th1 and the second threshold value Th2. In a scene where regenerative braking is performed when the control device 10 performs control according to the flow of FIG. 5, the time variation of input / output power in the drive device D, the power generation device G, and the battery 1 is controlled. This specific example is shown in comparison with the case where the control according to the flow of FIG. 3 is performed (first embodiment). It should be noted that the thick line graph in FIG. 6A performs the time change of the input / output power of the driving device D when the control according to the flow of FIG. 3 is performed, and the thin line graph performs the control according to the flow of FIG. The time change of the input / output power of the power generation device G in the case of the failure, and the broken line graph show the time change of the input / output power of the battery 1 when the control according to the flow of FIG. 3 is performed, respectively. ) Thick line graph when the control according to the flow of FIG. 5 is performed, the time variation of the input / output power of the driving device D, and the thin line graph when the control according to the flow of FIG. The time change of the input / output power of the battery 1 and the broken line graph show the time change of the input / output power of the battery 1 when the control according to the flow of FIG. 6 (a) and 6 (b) each take a common time T on the horizontal axis, and T21 starts the power generator G using regenerative power when control is performed according to the flow of FIG. The start timing, T22 is the start start timing of the power generator G using regenerative power when control according to the flow of FIG. 5 is performed, and T23 is the power generator when control according to the flow of FIG. 3 is performed. The start completion timing of G, T24 indicates the start completion timing of the power generator G when the control according to the flow of FIG. 6 is performed, and T25 indicates the timing when the regenerative braking by the drive device D ends.

  In the section of T20 ≦ T ≦ T21, regenerative braking is not performed, and the power generator G is started (whether the control according to the flow of FIG. 3 or the control according to the flow of FIG. 5 is performed). Since no engine start is performed, there is no difference between the graph in FIG. 6A and the graph in FIG.

  In the section of T21 ≦ T ≦ T22, regenerative braking is performed in a state where the amount of power stored in the battery 1 is lower than the second threshold Th2, but the regenerative power obtained by regenerative braking is not in a decreasing state. Therefore, when the control according to the flow of FIG. 3 is performed, the regenerative electric power from the drive device D is supplied to the generator 6, the engine 6 is cranked by the generator 6, and the generator G is started. Is done. This state is a state where the process of step S109 is performed in the flow of FIG. On the other hand, when the control according to the flow of FIG. 5 is performed, the power generator G is not started (engine start). This state is a state in which steps S205 to S209 are looped in the flow of FIG.

  In the section of T22 ≦ T ≦ T23, regenerative braking is performed in a state where the amount of power stored in the battery 1 is below the second threshold Th2, and the regenerative power obtained by regenerative braking is in a decreasing state. Therefore, when the control according to the flow of FIG. 5 is performed, the regenerative electric power from the driving device D is supplied to the generator 6 and the generator 6 is cranked by the generator 6, and the power generator G is started. This state is a state where the process of step S210 is performed in the flow of FIG.

  In the section of T23 ≦ T ≦ T24, when the control according to the flow of FIG. 3 is performed, the start-up of the power generator G is completed, and the generated power from the power generator G and the drive device D to the battery 1 are completed. Both regenerative power from is supplied. On the other hand, when the control according to the flow of FIG. 5 is performed, the power generator G is in a starting state.

  In the section of T24 ≦ T ≦ T25, even when the control according to the flow of FIG. 5 is performed, starting of the power generator G is completed, and the generated power from the power generator G to the battery 1 and the drive device D are Both regenerative power is supplied.

  Both when the control according to the flow of FIG. 3 is performed and when the control according to the flow of FIG. 5 is performed, both the generated power from the power generator G and the regenerative power from the drive device D for the battery 1. When the control according to the flow of FIG. 3 is performed, the section of T23 ≦ T ≦ T25 is performed. When the control according to the flow of FIG. 5 is performed, T24 ≦ T ≦ T25 is satisfied. It becomes a section and becomes shorter when the control according to the flow of FIG. 5 is performed. Therefore, it can be seen that by performing the control according to the flow of FIG. 5, it is possible to effectively suppress the loss when power is supplied to the battery 1 from both the power generation device G and the drive device D.

  As described above, in this embodiment, the control device 10 performs the control according to the flow of FIG. 5, so that the power generation device G can be started while maintaining the charged amount of the battery 1 within a range where the battery 1 does not deteriorate. It is possible to reduce the charge / discharge loss of the battery 1 by supplying as much necessary power as possible from the driving device D that is being regenerated. Further, the power generation device G that is generating power and the driving device D that is regenerating to the battery 1 can be reduced. Since loss in the battery 1 due to power supply from both sides can be effectively suppressed, the energy efficiency of the vehicle system can be greatly improved. Further, when there is a possibility that the battery 1 is sufficiently charged, for example, when traveling on a downhill road, the frequency of starting / stopping the power generating device G is suppressed as low as possible without starting the power generating device G. It is possible to further improve the energy efficiency of the vehicle system.

[Third embodiment]
FIG. 7 is a flowchart showing still another example (third embodiment) of the control by the control device 10 to which the present invention is applied. The feature of the control of the present embodiment is that when the power generation device G is in a non-power generation state and the amount of power stored in the battery 1 falls below the second threshold Th2 and regenerative braking is performed, regenerative braking obtained by regenerative braking is performed. It is determined whether or not the electric power exceeds the electric power required for starting the engine (engine starting) (hereinafter referred to as starting electric power), and when the regenerative electric power exceeds the starting electric power, The engine 5 is cranked by being supplied to the generator 6.

  When the flow of FIG. 7 is started, the control device 10 first confirms whether or not the power generation device G is in an operating state in step S301. Here, if the power generator G is in an operating state, the storage amount (SOC) of the battery 1 is acquired in step S302, and in step S303, it is determined whether or not the storage amount of the battery 1 has reached the upper limit threshold Th0. To do. Then, while the amount of power stored in the battery 1 is lower than the upper limit threshold Th0, the processes of step S302 and step S303 are periodically repeated. When the amount of stored power in the battery 1 reaches the upper limit threshold Th0, the power generator G Stop operation.

  On the other hand, when the power generation device G is in the non-power generation state, the control device 10 acquires the amount of charge (SOC) of the battery 1 in step S305, and in step S306, the amount of charge of the battery 1 is the second threshold Th2. Judge whether or not Then, the process of step S305 and step S306 is periodically repeated while the charged amount of the battery 1 is greater than or equal to the second threshold Th2, and the process proceeds to step S307 when the charged amount of the battery 1 falls below the second threshold Th2. .

  When the charged amount of the battery 1 falls below the second threshold Th2, the control device 10 determines whether or not the charged amount of the battery 1 has fallen to fall below the first threshold Th1 in step S307. In step S308, it is monitored whether or not regenerative braking has been performed while the amount of stored power is not less than the first threshold value Th1. If regenerative braking is performed before the amount of power stored in the battery 1 falls below the first threshold Th1, whether or not the regenerative power obtained by regenerative braking exceeds the starting power necessary for starting the power generator G in step S309. If the regenerative power exceeds the starting power, the regenerative power is supplied to the electric motor 6 and the engine 5 is cranked by the electric motor 6 to operate the power generator G in step S310.

  On the other hand, when the amount of power stored in the battery 1 is reduced to be less than the first threshold Th1 without performing regenerative braking, the control device 10 supplies the electric power from the battery 1 to the generator 6 in step S311. The engine 5 is cranked by this, and the power generator G is operated.

  As described above, in this embodiment, the control device 10 performs the control according to the flow of FIG. 7, so that the power generation device G can be started while maintaining the charged amount of the battery 1 within a range where the battery 1 does not deteriorate. It is possible to reduce the charge / discharge loss of the battery 1 by supplying as much necessary power as possible from the driving device D during regeneration. Further, when starting the power generation device G using regenerative power, the power required for starting is reduced. Since everything can be covered with regenerative power, the energy efficiency of the vehicle system can be greatly improved.

[Fourth embodiment]
FIG. 8 is a flowchart showing still another example (fourth embodiment) of the control by the control apparatus 10 to which the present invention is applied. The feature of the control of the present embodiment is that the threshold value for the charged amount of the battery 1 is larger than the first threshold value Th1 and larger than the second threshold value Th2 in addition to the first threshold value Th1 and the second threshold value Th2. When the third threshold value Th3, which is a small value, is used and the power generation apparatus G is in a non-power generation state and the amount of power stored in the battery 1 falls below the second threshold value Th2, regenerative braking is performed, If the charged amount is equal to or greater than the third threshold Th3, when the regenerative power exceeds the starting power, the regenerative power is supplied to the generator 6 to crank the engine 5, and the charged amount of the battery 1 is the third threshold value. If it is below the threshold Th3, the regenerative power is immediately supplied from the driving device D to the generator 6 to crank the engine 5.

  When the flow of FIG. 8 is started, the control device 10 first confirms whether or not the power generation device G is in an operating state in step S401. Here, if the power generation device G is in an operating state, the storage amount (SOC) of the battery 1 is acquired in step S402, and it is determined in step S403 whether the storage amount of the battery 1 has reached the upper limit threshold Th0. To do. Then, while the amount of power stored in the battery 1 is lower than the upper limit threshold Th0, the processes of step S402 and step S403 are periodically repeated. When the amount of stored power in the battery 1 reaches the upper limit threshold Th0, the power generator G Stop operation.

  On the other hand, when the power generation device G is in the non-power generation state, the control device 10 acquires the stored amount (SOC) of the battery 1 in step S405, and in step S406, the stored amount of the battery 1 is equal to the second threshold Th2. Judge whether or not Then, the process of step S405 and step S406 is periodically repeated while the stored amount of the battery 1 is equal to or greater than the second threshold Th2, and the process proceeds to step S407 when the stored amount of the battery 1 falls below the second threshold Th2. .

  If the charged amount of the battery 1 falls below the second threshold value Th2, the control device 10 determines whether or not the charged amount of the battery 1 has fallen to fall below the first threshold value Th1 in step S407. In step S408, it is monitored whether or not regenerative braking has been performed while the amount of stored power is not less than the first threshold value Th1. If regenerative braking is performed before the charged amount of the battery 1 falls below the first threshold Th1, it is determined in step S409 whether the charged amount of the battery 1 is equal to or greater than the third threshold Th3. Here, if the charged amount of the battery 1 is equal to or greater than the third threshold Th3, it is further determined in step S410 whether or not the regenerative power obtained by regenerative braking exceeds the starting power necessary for starting the power generator G. If the regenerative power exceeds the starting power, the regenerative power is supplied to the electric motor 6 and the engine 5 is cranked by the electric motor 6 to operate the power generator G in step S411. On the other hand, if the charged amount of the battery 1 is less than the third threshold Th3, the process proceeds to step S411 without performing the determination in step S410, and regenerative power is immediately supplied to the motor 6 and the motor 6 cranks the engine 5. And the power generator G is operated.

  In addition, when the stored amount of the battery 1 is reduced to be below the first threshold Th1 without performing regenerative braking, the control device 10 supplies the power from the battery 1 to the generator 6 in step S412. Then, the engine 5 is cranked by the electric motor 6 and the power generator G is operated.

  As described above, in the present embodiment, the control device 10 performs control according to the flow of FIG. 8, so that the power generation device G can be started while maintaining the charged amount of the battery 1 within a range where the battery 1 does not deteriorate. It is possible to reduce the charge / discharge loss of the battery 1 by supplying as much necessary power as possible from the regenerating drive device D. Furthermore, when starting the power generation device G using regenerative power, the power required for starting is reduced. Since it is possible to switch according to the amount of power stored in the battery 1 whether to cover part of it with regenerative power or all of it with regenerative power, the energy efficiency of the vehicle system can be greatly improved.

[Fifth embodiment]
FIG. 9 is a flowchart showing still another example (fifth embodiment) of control by the control device 10 to which the present invention is applied. The control feature of the present embodiment is not to use a fixed value as the second threshold value Th2 with respect to the charged amount of the battery 1, but to change the value according to the past start history (engine start history) of the power generator G. The variable threshold is used.

  When the flow of FIG. 9 is started, the control device 10 first confirms whether or not the power generation device G is in an operating state in step S501. Here, if the power generator G is in an operating state, the storage amount (SOC) of the battery 1 is acquired in step S502, and in step S503, it is determined whether or not the storage amount of the battery 1 has reached the upper limit threshold Th0. To do. Then, while the amount of electricity stored in the battery 1 is lower than the upper limit threshold Th0, the processes of step S502 and step S503 are periodically repeated. When the amount of electricity stored in the battery 1 reaches the upper limit threshold Th0, the power generator G Stop operation.

  On the other hand, when the power generation device G is in the non-power generation state, the control device 10 acquires the storage amount (SOC) of the battery 1 in step S505, and in step S506, the storage amount of the battery 1 is the second threshold Th2. Judge whether or not Then, while the amount of power stored in the battery 1 is equal to or greater than the second threshold Th2, the processing of Step S505 and Step S506 is periodically repeated, and the process proceeds to Step S507 when the amount of power stored in the battery 1 falls below the second threshold Th2. .

  When the charged amount of the battery 1 falls below the second threshold value Th2, the control device 10 determines whether or not the charged amount of the battery 1 has dropped below the first threshold value Th1 in step S507. In step S508, it is monitored whether or not regenerative braking has been performed while the amount of stored power is not less than the first threshold value Th1. If regenerative braking is performed before the amount of power stored in the battery 1 falls below the first threshold Th1, in step S509, regenerative power is supplied to the electric motor 6 to crank the engine 5 by the electric motor 6, and the power generator Activate G. Thereafter, in step S510, the control device 10 corrects the value of the second threshold Th2 downward by a predetermined amount (for example, about 1 to 2%).

  On the other hand, when the amount of power stored in the battery 1 is reduced to less than the first threshold value Th1 without performing regenerative braking, the control device 10 supplies the electric power from the battery 1 to the generator 6 in step S511, and the electric motor 6 The engine 5 is cranked by this, and the power generator G is operated. Thereafter, in step S512, the control device 10 corrects the value of the second threshold Th2 upward by a predetermined amount (for example, about 1 to 2%).

  FIG. 10 is a diagram for explaining the effect of the present embodiment. FIG. 10A shows an example of a temporal change (vehicle speed pattern) of the vehicle speed of the electric vehicle, and FIG. 10B is a diagram of FIG. The relationship between the value at which the energy efficiency of the vehicle system converges when the vehicle speed pattern is repeated and the width of the first threshold Th1 and the second threshold Th2 used for control is shown.

  As can be seen from the graph of FIG. 10B, there is an optimum value for the width of the first threshold Th1 and the second threshold Th2 in increasing the energy efficiency of the vehicle system. As the width of the first threshold Th1 and the second threshold Th2 becomes smaller than the optimum value, the time from when the charged amount of the battery 1 falls below the second threshold Th2 to below the first threshold Th1 becomes shorter. As a result, the probability that the power consumption associated with the starting of the power generator G can be supplied from the regenerating drive device D is reduced, and the energy efficiency of the vehicle system is lowered.

  On the other hand, as the width of the first threshold value Th1 and the second threshold value Th2 becomes larger than the optimum value, the power generation device G starts in a state where the amount of power stored in the battery 1 is large. The time until the power storage device 1 stops when the amount of stored electricity of 1 reaches the upper limit threshold Th0 is shortened. As a result, the frequency of starting / stopping of the power generation apparatus G increases, and the ratio of the start / stop transition time, which is less efficient than the steady operation, to the time during which the power generation apparatus G operates efficiently and stably increases. However, the energy efficiency of the vehicle system decreases.

  That is, by supplying the power consumption accompanying the start of the power generation apparatus G from the regenerating drive device D as much as possible, and by setting the second threshold Th2 so that the frequency of the start / stop of the power generation apparatus G is reduced, The energy efficiency of the vehicle system can be further improved. However, the above conditions change depending on the state of the electric vehicle, and the optimal value as the second threshold Th2 changes accordingly. Therefore, in this embodiment, the second threshold value Th2 is not a fixed value but a variable threshold value, and the second threshold value Th2 can be updated to an optimum value as needed according to the vehicle running pattern that changes every moment.

  As described above, in the present embodiment, the control device 10 performs control according to the flow of FIG. 9, so that the power generation device G can be started while maintaining the charged amount of the battery 1 within a range where the battery 1 does not deteriorate. The necessary electric power can be supplied from the regenerating drive device D as much as possible to reduce the charge / discharge loss of the battery 1, and the frequency of starting / stopping the power generation device G can be reduced. As a result, the energy efficiency can be greatly improved.

[Sixth embodiment]
FIG. 11 is a flowchart showing still another example (sixth embodiment) of control by the control device 10 to which the present invention is applied. The control feature of the present embodiment is that when the power generation device G is in a non-power generation state and the amount of power stored in the battery 1 decreases to fall below the second threshold Th2 and regenerative braking is performed, The regenerative power obtained by regenerative braking is stored in the battery 1 without being supplied to the electric motor 6 when the vehicle speed is equal to or lower than the predetermined value.

  When the flow of FIG. 11 is started, the control device 10 first confirms whether or not the power generation device G is in an operating state in step S601. Here, if the power generator G is in an operating state, the storage amount (SOC) of the battery 1 is acquired in step S602, and it is determined in step S603 whether the storage amount of the battery 1 has reached the upper limit threshold Th0. To do. Moreover, the control apparatus 10 acquires the vehicle speed of an electric vehicle at any time, and monitors whether the vehicle speed became N1 or less, which is a value indicating low speed travel (step S604). Then, while the stored amount of the battery 1 is lower than the upper limit threshold Th0 and the vehicle speed of the electric vehicle exceeds N1, the processing of step S602 to step S604 is periodically repeated, and the stored amount of the battery 1 is increased to the upper limit. When the threshold value Th0 is reached or the vehicle speed of the electric vehicle becomes N1 or less, the operation of the power generator G is stopped in step S605. Here, the reason why the operation of the power generation device G is stopped when the vehicle speed of the electric vehicle is N1 or less is to ensure quietness in the passenger compartment during low-speed traveling.

  On the other hand, when the power generation device G is in the non-power generation state, the control device 10 acquires the amount of storage (SOC) of the battery 1 in step S606, and in step S607, the amount of storage of the battery 1 is the second threshold Th2. Judge whether or not Then, the process of step S606 and step S607 is periodically repeated while the storage amount of the battery 1 is greater than or equal to the second threshold Th2, and the process proceeds to step S608 when the storage amount of the battery 1 falls below the second threshold Th2. .

  When the charged amount of the battery 1 falls below the second threshold Th2, the control device 10 determines whether or not the charged amount of the battery 1 has dropped below the first threshold Th1 in step S607. In step S609, it is monitored whether or not regenerative braking has been performed while the amount of stored power is not less than the first threshold value Th1. If regenerative braking is performed before the stored amount of the battery 1 falls below the first threshold Th1, it is determined in step S610 whether the vehicle speed of the electric vehicle exceeds a predetermined value N2, and the vehicle speed of the electric vehicle is determined. If it exceeds the predetermined value N2, in step S611, regenerative electric power obtained by regenerative braking is supplied to the electric motor 6, the engine 6 is cranked by the electric motor 6, and the power generator G is operated. On the other hand, when the vehicle speed of the electric vehicle is equal to or less than the predetermined value N2, the regenerative power is stored in the battery 1 without being supplied to the generator 6. Note that the predetermined value N2 here is a value predicted that the vehicle speed of the electric vehicle will become the vehicle speed N1 for stopping the above-described power generation device G in the near future, for example, a vehicle speed higher by about 5 to 10 km / h than N1 described above. Is set.

  In addition, when the stored amount of the battery 1 is reduced to be lower than the first threshold value Th1 without performing regenerative braking, the control device 10 supplies the electric power from the battery 1 to the generator 6 in step S612 and the electric motor 6 The engine 5 is cranked by this, and the power generator G is operated.

  As described above, in the present embodiment, the control device 10 performs control according to the flow of FIG. 11, so that the power generation device G can be started while maintaining the charged amount of the battery 1 within a range where the battery 1 does not deteriorate. The necessary power can be supplied from the regenerating drive device D as much as possible to reduce the charge / discharge loss of the battery 1, and the power generation device G can be started even when the power generation device G is stopped when the electric vehicle runs at low speed. / Because it is possible to suppress an increase in the frequency of stopping, the energy efficiency of the vehicle system can be greatly improved.

  The embodiment of the present invention described above is merely an example of application of the present invention, and the technical scope of the present invention is intended to be limited to the contents disclosed as the above-described embodiment. Not what you want. That is, the technical scope of the present invention is not limited to the specific technical matters disclosed in the above-described embodiments, but includes various modifications, changes, alternative techniques, and the like that can be easily derived from this disclosure.

It is a lineblock diagram showing an example of an electric vehicle to which the present invention is applied. It is a figure explaining operation | movement of the electric power generating apparatus at the time of changing to a power generation state from a non-power generation state. It is a flowchart which shows an example (1st Example) of control by the control apparatus to which this invention is applied. It is a figure which shows the specific example of the mode of the time change of the input / output electric power in a drive device, an electric power generating apparatus, and a battery, and the charge amount of a battery when a control apparatus performs control according to the flow of FIG. It is a flowchart which shows the other example (2nd Example) of the control by the control apparatus to which this invention is applied. When the control device performs control according to the flow of FIG. 5, a specific example of the state of time change of input / output power in the drive device, the power generation device, and the battery is controlled according to the flow of FIG. 3. It is a figure shown in comparison. It is a flowchart which shows the further another example (3rd Example) of the control by the control apparatus to which this invention is applied. It is a flowchart which shows the further another example (4th Example) of the control by the control apparatus to which this invention is applied. It is a flowchart which shows the further another example (5th Example) of the control by the control apparatus to which this invention is applied. It is a figure explaining the effect when a control device performs control according to the flow of FIG. It is a flowchart which shows the further another example (6th Example) of the control by the control apparatus to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery 2 Drive motor 5 Engine 6 Generator 10 Control apparatus 11 Battery controller 12 Drive system controller 13 Power generation system controller D Drive apparatus G Power generation apparatus Th1 1st threshold value Th2 2nd threshold value Th3 3rd threshold value

Claims (6)

A drive motor that generates a driving force of the vehicle, a battery that stores electric power to be supplied to the drive motor, an engine that is controlled to start / stop according to the amount of storage of the battery, and driven by the engine to generate electric power A control device for an electric vehicle comprising a generator, wherein the generator functions as a motor for starting the engine when the engine is started,
As a threshold value for the amount of electricity stored in the battery, a first threshold value and a second threshold value that is larger than the first threshold value,
The regenerative power obtained by regenerative braking is supplied to the generator when regenerative braking is performed when the amount of power stored in the battery falls below the second threshold when the engine is stopped. Start
A control device for an electric vehicle, wherein when the amount of electricity stored in the battery falls below the first threshold without starting the engine, electric power is supplied from the battery to the generator to start the engine.   When the amount of electricity stored in the battery falls below the second threshold while the engine is stopped, regenerative braking is performed, and when the regenerative power obtained by regenerative braking is once increased and then reduced, The electric vehicle control device according to claim 1, wherein regenerative power is supplied to the generator to start the engine.   If the amount of electricity stored in the battery falls below the second threshold while the engine is stopped, regenerative braking is performed, and the regenerative power obtained by regenerative braking exceeds the power required for starting the engine. 2. The electric vehicle control device according to claim 1, wherein the regenerative power is supplied to the generator to start the engine. The threshold for the amount of electricity stored in the battery further includes a third threshold that is larger than the first threshold and smaller than the second threshold,
If the charged amount of the battery falls below the second threshold value while the engine is stopped, regenerative braking is performed if the charged amount is greater than or equal to the third threshold value, and is obtained by regenerative braking. When the regenerative power generated exceeds the power required for starting the engine, the regenerative power is supplied to the generator to start the engine,
If the stored amount of the battery falls below the third threshold without starting the engine, when regenerative braking is performed, regenerative power obtained by regenerative braking is supplied to the generator to The electric vehicle control device according to claim 1, wherein the electric vehicle control device is started.   5. The control device for an electric vehicle according to claim 1, wherein the second threshold value is a variable threshold value whose value is changed according to a past start history of the engine.   Even when the amount of power stored in the battery is below the second threshold and the regenerative braking is performed with the engine stopped, if the vehicle speed of the electric vehicle is equal to or lower than a predetermined value, the regenerative braking can be obtained. 6. The electric vehicle control device according to claim 1, wherein the generated regenerative electric power is stored in the battery and the engine is not started. 6.

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