JP7459752B2 - Regenerative control method and regenerative control device - Google Patents

Description

The present invention relates to a regeneration control method and a regeneration control device.

Hitherto, hybrid vehicles that use both a motor and an engine have been popular. For example, a series hybrid vehicle is known as one type of hybrid vehicle. A series hybrid vehicle is an electric vehicle in which drive torque is generated exclusively by a motor, and in a series hybrid vehicle, the engine is used as a generator for charging a battery that supplies power to the motor.

Hybrid vehicles such as series hybrid vehicles use regenerative control, which generates braking torque with a motor and recovers power in a battery. However, regenerative control is unable to generate sufficient regenerative braking torque at the drive wheels when the battery is close to full charge. For this reason, Patent Document 1 discloses a technology that allows regenerative control to continue in series hybrid vehicles by driving the engine with a power generating motor (so-called motoring) at the same time as regenerative control.

JP2006-280161A

As described in Patent Document 1, if the engine is powered and rotated using regenerative electric power, regenerative braking torque can be generated even when the battery is nearly fully charged. However, this engine is for power generation and is not connected to drive wheels or the like. Therefore, when this engine is driven to consume regenerated electric power, the engine rotational speed will fluctuate greatly. As a result, noise and vibration occur in response to fluctuations in engine speed, which tends to lead to deterioration in sound and vibration performance.

Furthermore, the motor (generator) connected to the engine for power generation is often smaller than the motor for drive. For this reason, even if the amount of electric power that can be used for powering rotation of the motor connected to the power generation engine is used, sufficient regenerative braking torque may still not be generated at the drive wheels.

Furthermore, when the battery is close to being fully charged, the motor connected to the generator engine is often stopped. In this way, if you try to use a stopped generator motor to consume excess regenerative power, current will flow through only some of the windings, which can cause overheating.

The present invention provides a regeneration control method and a regeneration control device that can generate regenerative braking torque while preventing deterioration of sound vibration performance and overheating of a power generation motor even when the state of charge of a battery is close to full charge. The purpose is to

A regeneration control method according to an aspect of the present invention includes a drive motor that generates drive torque to the drive wheels by supplying power from a battery, and generates regenerative braking torque to the drive wheels by recovering the power from the battery, and an engine. A regeneration control method for an electric vehicle including a non-drive motor that supplies power to a battery when driven. In this embodiment of the regeneration control method, regenerative power that is generated to obtain regenerative braking torque is calculated, and chargeable power of the battery is calculated. Further, at least when surplus power is generated by regeneration control due to regenerative power exceeding chargeable power, the surplus power is consumed by the drive motor and the non-drive motor. Then, with respect to generation or increase/decrease of surplus power, the following speed of power consumption in the non-driving motor is made slower than the following speed of power consumption in the driving motor.

The regenerative control method and regenerative control device of the present invention can generate regenerative braking torque while preventing deterioration of sound and vibration performance and overheating of the generator motor, even when the battery is nearly fully charged.

FIG. 1 is a block diagram showing the configuration of an electric vehicle. FIG. 2 is a block diagram showing the configuration of the controller. FIG. 3 is a block diagram showing the configuration of the braking/driving torque control unit. FIG. 4 is a block diagram showing the configuration of the power consumption control unit. FIG. 5 is an explanatory diagram showing the relationship between the vehicle speed and the follow-up speed of the power consumption in the generator motor. FIG. 6 is a block diagram showing the configuration of the drive motor control unit. FIG. 7 is a block diagram showing the configuration of the generator motor control unit. FIG. 8 is an explanatory diagram showing a method of adjusting power consumption in the drive motor and the generator motor. FIG. 9 is a flowchart showing the operation of the electric vehicle according to the first embodiment. FIG. 10 is a timing chart showing changes in (A) braking/driving torque of the drive motor, (B) surplus power, and (C) power consumption when the electric vehicle decelerates. FIG. 11 is a flowchart of a determination process added in the second embodiment. FIG. 12 is a timing chart showing the transition of (A) the braking/driving torque of the drive motor, (B) surplus power, and (C) power consumption when an electric vehicle decelerates in a situation where the engine torque fluctuates greatly. FIG. 13 is a graph showing a correction process performed on the follow-up speed of power consumption in the generator motor in the third embodiment. FIG. 14 is a flowchart of a determination process added in the fourth embodiment.

The following describes an embodiment of the present invention with reference to the drawings.

[First embodiment]
Fig. 1 is a block diagram showing the configuration of an electric vehicle 100. As shown in Fig. 1, the electric vehicle 100 includes drive wheels 10, a power train 11, a controller 12, and an operation unit 13.

The drive wheels 10 are the wheels of the electric vehicle 100. A driving force and/or a braking force is transmitted to the drive wheels 10 from the powertrain 11. As a result, a driving torque for driving the electric vehicle 100 and/or a braking torque for braking the electric vehicle 100 are generated in the drive wheels 10.

The power train 11 generates driving torque and braking torque (hereinafter referred to as braking/driving torque) to the driving wheels 10 . Powertrain 11 includes a battery 14 and a battery parameter detector 15 .

The battery 14 is an energy source for driving the electric vehicle 100. The battery parameter detector 15 detects the SOC (state of charge) of the battery 14, the temperature Tb of the battery 14, and the current full charge capacity relative to the initial full charge capacity (so-called SOH (State Of Health)). Various battery parameters detected by the battery parameter detector 15 are input to the controller 12.

The power train 11 also includes an inverter 16, a current detector 17, a drive motor 18, an electrical angle detector 19, and a speed reducer 20. These constitute a braking/driving torque generation system that generates braking/driving torque to the drive wheels 10.

Inverter 16 converts the DC voltage applied from battery 14 into AC voltage and supplies it to drive motor 18 when electric vehicle 100 is driven. Furthermore, when the electric vehicle 100 is braked, the inverter 16 can supply regenerative power generated by the drive motor 18 to the battery 14 to charge the battery 14.

Current detector 17 detects the current supplied by inverter 16 to drive motor 18 when electric vehicle 100 is driven. Further, current detector 17 detects the current input from drive motor 18 to inverter 16 when electric vehicle 100 decelerates. The current detected by the current detector 17 is input to the controller 12. In this embodiment, the drive motor 18 is a three-phase synchronous AC motor having a U phase, a V phase, and a W phase. Therefore, the current detector 17 detects the currents I1u, I1v, and I1w (see FIG. 6) of each phase. However, the current detector 17 can detect any two-phase current among these three-phase currents, and the remaining one-phase current can be calculated by the controller 12.

Drive motor 18 is a drive electric motor, and is a first electric motor included in electric vehicle 100 . Drive motor 18 is a source of driving force for electric vehicle 100 and is connected to drive wheels 10 via reduction gear 20 . The drive motor 18 generates a drive torque to the drive wheels 10 by being operated by receiving power from the battery parameter detector 15 via the inverter 16 . The drive motor 18 also functions as a generator. That is, when electric vehicle 100 decelerates, drive motor 18 acts as a load on the rotation of drive wheels 10 and generates braking torque (hereinafter referred to as regenerative braking torque) to drive wheels 10 . Through this regenerative braking, the drive motor 18 recovers electric power (hereinafter referred to as regenerative electric power). Therefore, the drive motor 18 generates drive torque to the drive wheels 10 by supplying power from the battery 14, and also generates regenerative braking torque to the drive wheels 10 by recovering the power to the battery 14.

The electrical angle detector 19 detects the electrical angle θd (see FIG. 6) of the drive motor 18. The electrical angle θd detected by the electrical angle detector 19 is input to the controller 12. The electrical angle θd is appropriately converted into the rotation speed Nd (see FIG. 2) or electrical angular velocity ωd (not shown) of the drive motor 18 in the controller 12, and used to control the electric vehicle 100.

The reducer 20 reduces the rotational speed of the output shaft of the drive motor 18 and transmits it to the drive wheel 10. As a result, the reducer 20 generates a torque (drive torque) in the drive wheel 10 according to the reduction ratio.

The powertrain 11 also includes an engine 21, an engine parameter detector 22, a reduction gear 23, a generator motor 24, an electrical angle detector 25, a current detector 26, and an inverter 27. These constitute a power generation system that generates charging power to be supplied to the battery 14.

The engine 21 is connected to a generator motor 24 via a reduction gear 23. Torque generated by combustion in the engine 21 (hereinafter referred to as combustion torque) is used exclusively to drive the generator motor 24. That is, electric vehicle 100 is a so-called series hybrid vehicle. Furthermore, when the generator motor 24 is driven by electric power supplied from the battery 14 or the like, the engine 21 is rotated by the generator motor 24 without depending on its own combustion. In this way, driving the generator motor 24 with the electric power of the battery 14 and running the engine 21 idly for the purpose of using the electric power of the battery 14 is called motoring. In motoring, the generator motor 24 is driven with maximum power efficiency, and the electric power of the battery 14 is mainly converted into heat by the engine 21.

The engine parameter detector 22 detects various parameters that indicate the operating state of the engine 21, such as the rotation speed N _E (see FIG. 5) of the engine 21. The engine parameter detector 22 is composed of one or more detectors for detecting these engine parameters.

The reducer 23 reduces the rotational speed of the output shaft of the engine 21 and outputs it to the generator motor 24. As a result, the reducer 23 drives the generator motor 24 with a torque according to the reduction ratio.

Generation motor 24 is a second electric motor that electric vehicle 100 has. However, the generator motor 24 is mainly used as a generator to generate electric power for charging the battery 14, and is not used to drive the electric vehicle 100 (generate driving torque or braking torque). When generating electric power to be supplied to the battery 14, the generator motor 24 is driven by the engine 21. Electric power generated by the generator motor 24 is supplied to the battery 14 via the inverter 27. That is, the generator motor 24 is a "non-driving motor" (non-driving motor) that is driven by the engine 21 to supply electric power to the battery 14 . Further, the generator motor 24 may be driven using the electric power of the battery 14 in order to perform motoring.

The electrical angle detector 25 detects the electrical angle θg (see FIG. 7) of the generator motor 24. The electrical angle θg detected by the electrical angle detector 25 is input to the controller 12. The electrical angle θg is appropriately converted into the rotation speed Ng (see FIG. 2) or electrical angular velocity ωg (not shown) of the generator motor 24 in the controller 12, and is used to control the electric vehicle 100.

The current detector 26 detects the current input to the battery 14 via the inverter 27 or the current supplied from the battery 14 to the generator motor 24 via the inverter 27. The current detected by current detector 26 is input to controller 12. In this embodiment, the generator motor 24 is a three-phase synchronous AC motor having a U phase, a V phase, and a W phase. Therefore, the current detector 26 detects the currents I2u, I2v, and I2w (see FIG. 7) of each phase. However, the current detector 26 can detect any two-phase current among these three-phase currents, and the remaining one-phase current can be calculated by the controller 12.

The inverter 27 converts the AC voltage output by the generator motor 24 into a DC voltage and supplies it to the battery 14. This allows the battery 14 to be charged with the power generated by the generator motor 24. When motoring is performed, the inverter 27 also converts the DC voltage of the battery 14 into an AC voltage and supplies it to the generator motor 24.

In addition to the above, the power train 11 includes a friction brake 28. The friction brake 28 brakes the drive wheels 10 by friction force. The friction brake 28 is driven at least by the driver's operation of the brake pedal. The friction brake 28 may be driven under the control of the controller 12. When the friction brake 28 is driven under the control of the controller 12, the friction brake 28 and the drive motor 18 are controlled in cooperation. That is, the controller 12 can generate a braking torque required for braking the electric vehicle 100 by combining the braking torque generated by the friction brake 28 (hereinafter referred to as friction braking torque) and the regenerative braking torque generated by the drive motor 18. However, in this embodiment, the friction brake 28 is not controlled by the controller 12. Therefore, the friction brake 28 does not operate except when the driver operates the brake pedal.

The controller 12 generates control signals for directly or indirectly controlling each part constituting the powertrain 11, and controls them. For example, the controller 12 controls the drive motor 18 and the generator motor 24, which is a non-drive motor. In this way, the controller 12 comprehensively controls the drive and braking of the electric vehicle 100, and the charging or discharging of the battery 14. In addition, in order to generate the above control signals, the controller 12 acquires various vehicle information and uses the information to generate the above control signals. The vehicle information is various parameters indicating the operating state of the electric vehicle 100 and the operating state of each part constituting the powertrain 11, and includes parameters that can be directly acquired by detection or the like, as well as parameters that are calculated using the detected parameters. In this embodiment, the braking/driving torque T of the drive wheels 10, the rotation speed Nd of the drive motor 18, the rotation speed Ng of the generator motor 24, the combustion torque Tc of the engine 21, and the rotation speed N _E of the engine 21 can be acquired and used as vehicle information at any timing. For example, the temperature Tb and SOC of the battery 14 are vehicle information of the electric vehicle 100. The vehicle information also includes the currents I1u, I1v, and I1w of the drive motor 18, and the electrical angle θd, rotation speed Nd, and electrical angular velocity ωd of the drive motor 18. The vehicle information also includes the rotation speed N _E of the engine 21, and the electrical angle θg, rotation speed Ng, and electrical angular velocity ωg of the generator motor 24.

The controller 12 is a computer including, for example, a central processing unit (CPU), a random access memory (RAM), an input/output interface (I/O interface), and the like. Further, the controller 12 is programmed to periodically control each part of the power train 11 at a predetermined control cycle.

In this embodiment, when the regenerative power exceeds the power that can be charged to the battery 14, and surplus power Ps (see FIG. 10) is generated by the regenerative control according to the deviation between the regenerative power and the power that can be charged, the controller 12 causes the drive motor 18 and the generator motor 24, which is a non-drive motor, to consume the surplus power Ps.

The consumption of surplus power Ps referred to here is achieved by using more power than the predetermined power that normally drives the drive motor 18 and the generator motor 24 (for example, the power used when driven at maximum power efficiency). Realized. Moreover, the consumption of the surplus power Ps is mainly realized by the inverter 16 connected to the drive motor 18 and the inverter 27 connected to the generation motor 24 converting the surplus power Ps into heat. That is, consuming the surplus power Ps "by the drive motor 18 and the generator motor 24" means that the inverter 16 and the inverter 27 mainly convert the surplus power Ps into heat when driving the drive motor 18 and the generator motor 24. means. Therefore, when the consumption of surplus power Ps in this embodiment is compared with the use of electric power by motoring, they are common in that they convert electric power into heat, but the entities that convert electric power into heat are different. In the following, the same applies to "consumption" when referring to power consumption etc. with respect to the drive motor 18 and the power generation motor 24.

Then, the controller 12 changes the follow-up speed δg (see FIGS. 5 and 10) of the power consumption in the generation motor 24, which is a non-drive motor, to the power consumption in the drive motor 18 in response to the generation or increase/decrease of the surplus power Ps. The tracking speed is made slower than the following speed δd (see FIG. 10). The specific configuration of the controller 12 and regeneration control method for this purpose will be described in detail later.

In this embodiment, surplus power refers to the power that can be additionally charged by the battery 14 (full charge capacity), considering a realistic margin Pm (not shown) of the regenerative power generated by the drive motor 18 This refers to the amount of electricity that exceeds the current charging capacity. Furthermore, "occurrence" of surplus power means that surplus power Ps has actually occurred, that surplus power Ps will definitely occur in the future, or that surplus power Ps is expected to occur in the future. An increase or decrease in surplus power Ps refers to an increase or decrease in the actually generated surplus power Ps, the surplus power Ps that will definitely be generated in the future, or the prospect that surplus power Ps will occur in the future.

In addition, in this embodiment, the tracking speed δd of the power consumption in the drive motor 18 is the rate of change of the power consumption by the drive motor 18. That is, the tracking speed δd of the power consumption in the drive motor 18 refers to the speed at which the power consumption in the drive motor 18 occurs or increases or decreases in response to the generation or increase or decrease of the surplus power Ps. Similarly, the tracking speed δg of the power consumption in the generator motor 24 is the rate of change of the power consumption by the generator motor 24. That is, the tracking speed δg of the power consumption in the generator motor 24 refers to the speed at which the power consumption in the drive motor 18 occurs or increases or decreases in response to the generation or increase or decrease of the surplus power Ps. That is, the tracking speed δd of the drive motor 18 and the tracking speed δg of the generator motor 24 represent how long it takes for the power consumption to reach the target power consumption. The target power consumption is determined according to the surplus power Ps for each of the drive motor 18 and the generator motor 24. When the drive motor 18 and the generator motor 24 are of the same type, for example, 50% of the surplus power Ps can be set as the target power consumption of the drive motor 18 and the generator motor 24.

The operation unit 13 is composed of a steering wheel, an accelerator pedal, a brake pedal, a shift lever, etc. that are directly operated by the driver, and detectors that detect the operation states of these (none of which are shown). The operation unit 13 also includes switches that turn the operation mode of the electric vehicle 100 on/off or switch between modes. The operation states of these parts of the operation unit 13 can be acquired by the controller 12 at any time as vehicle information of the electric vehicle 100. For example, the accelerator opening Apo (see FIG. 2), which is determined according to the amount of operation of the accelerator pedal, is acquired by the controller 12 as vehicle information.

FIG. 2 is a block diagram showing the configuration of the controller 12. As shown in FIG. 2, the controller 12 includes (1) a braking/driving torque control section 31, (2) a power consumption control section 32, (3) an engine control section 33, (4) a drive motor control section 34, and ( 5) Includes a generator motor control section 35.

(1) Braking/driving torque control unit The braking/driving torque control unit 31 calculates a target torque T ^* based on the accelerator opening Apo and the rotation speed Nd of the drive motor 18. The target torque T ^* is a target value of the braking/driving torque to be generated at the drive wheels 10 by the powertrain 11. The target torque T ^* is input to the drive motor control unit 34.

Figure 3 is a block diagram showing the configuration of the braking/driving torque control unit 31. As shown in Figure 3, the braking/driving torque control unit 31 includes a vehicle speed calculation unit 41, a target torque calculation unit 42, and a target torque limiting unit 43.

The vehicle speed calculation unit 41 calculates the vehicle speed V of the electric vehicle 100 based on the rotation speed Nd of the drive motor 18. In this embodiment, the vehicle speed V of the electric vehicle 100 is calculated, but when a wheel speed sensor is provided on the drive wheel 10 or the like, the detected wheel speed can be used as the vehicle speed V of the electric vehicle 100.

The target torque calculation unit 42 calculates the target torque T ^* based on the accelerator opening Apo and the vehicle speed V. Target torque T ^* is a target value of braking/driving torque. When the target torque T ^* is a positive value, the target torque T ^* represents the target value of the driving torque. On the other hand, when target torque T ^* is a negative value, target torque T ^* represents a target value of braking torque due to regeneration (hereinafter referred to as regenerative braking torque). That is, when regenerative control is executed, target torque T ^* represents target regenerative braking torque. The target torque T ^* is input to the drive motor control section 34 via the target torque limiting section 43.

Furthermore, the target torque calculation unit 42 calculates the target torque T ^* and also calculates the target rotation speed Nd ^* of the drive motor 18 for realizing the braking/driving torque equivalent to the target torque T ^* . The target rotation speed Nd ^* of the drive motor 18 is determined so as to realize the braking/driving torque equivalent to the target torque T ^* with substantially maximum power efficiency. The target rotation speed Nd ^* of the drive motor 18 is input to the power consumption control unit 32.

The target torque calculation unit 42 holds a map in which the target torque T ^* and the target rotation speed Nd ^* are determined in advance for each operating point (driving point) determined by, for example, the accelerator opening Apo and the vehicle speed V. Therefore, the target torque calculation unit 42 refers to this map to calculate the target torque T ^* and the target rotation speed Nd* corresponding to the current accelerator opening Apo and the vehicle speed V. In other words, the values of the target torque T ^* and the target rotation speed Nd ^* calculated by the target torque calculation unit 42 are static values determined by the current accelerator opening Apo and ^the vehicle speed V.

The target torque limiting unit 43 dynamically limits the time rate of change of the target torque T ^* , etc., in order to maintain the drivability of the electric vehicle 100. The target torque T ^* to which the time rate of change, etc. has been limited is output to the drive motor control unit 34.

(2) Power Consumption Control Unit The power consumption control unit 32 (see FIG. 2) calculates a target value of power consumption in the drive motor 18 (hereinafter referred to as target power consumption of the drive motor 18) Pcd ^* . Further, the power consumption control unit 32 calculates a target value of power consumption in the generation motor 24 (hereinafter referred to as target power consumption of the generation motor 24) Pcg ^* .

The target power consumption Pcd ^* of the drive motor 18 and the target power consumption Pcg ^* of the generator motor 24 are calculated at least when regenerative power is generated, and are input to the drive motor control unit 34 and the generator motor control unit 35, respectively. The target power consumption Pcd ^* of the drive motor 18 and the target power consumption Pcg ^* of the generator motor 24 are short-term power consumption target values set, for example, at each predetermined control period, and change over time. The rate of change over time of the target power consumption Pcd ^* of the drive motor 18 and the target power consumption Pcg ^* of the generator motor 24 is set individually. The rate of change over time of the target power consumption Pcg ^* of the generator motor 24 is smaller than the rate of change over time of the target power consumption Pcg ^* of the drive motor 18. For this reason, the speed at which the target power consumption Pcg ^* of the generator motor 24 follows the generation or increase/decrease of surplus power is slower than the target power consumption Pcd ^* of the drive motor 18.

FIG. 4 is a block diagram showing the configuration of the power consumption control section 32. As shown in FIG. As shown in FIG. 4, the power consumption control unit 32 includes a target regenerative power calculation unit 44, a chargeable power calculation unit 45, a first consumable power calculation unit 46, a second consumable power calculation unit 47, and a target A power calculation unit 48 is provided.

The target regenerative power calculating unit 44 calculates the target regenerative power Preg ^* based on the target torque T ^* (target regenerative braking torque) and the target rotation speed Nd ^* of the drive motor 18 when regenerative control is executed. . Target regenerative power Preg ^* is an expected value of regenerative power. That is, the target regenerative power Preg ^* represents the regenerative power generated in response to a predetermined regenerative braking torque being generated at the drive wheels 10. The target regenerative power Preg ^* is input to the target power consumption calculation section 48.

The chargeable power calculation unit 45 calculates the chargeable power ΔP of the battery 14. The chargeable power ΔP of the battery 14 is calculated based on the SOC of the battery 14, the temperature Tb of the battery 14, and the like. More specifically, the chargeable power ΔP of the battery 14 is, in principle, a chargeable power (hereinafter referred to as basic chargeable power) D _P determined according to the state of the battery 14, such as the SOC and the temperature Tb. In this embodiment, more realistically, the total value (hereinafter referred to as loss power) P _loss of the power consumed by the drive motor 18, the generator motor 24, the auxiliary machinery, and each of the other parts in the current operating state, and a predetermined margin Pm for ensuring safety, etc. are taken into consideration. That is, the chargeable power ΔP of the battery 14 is calculated by subtracting the margin Pm from the sum of the basic chargeable power D _P and the loss power P _loss . That is, ΔP=D _P +P _loss -Pm.

The first consumable power calculation unit 46 calculates the upper limit of the additional power that can be consumed by the drive motor 18 (hereinafter referred to as the consumable power of the drive motor 18) Pcd based on the current braking/driving torque T of the drive wheels 10 and the current rotation speed Nd of the drive motor 18.

In principle, the drive motor 18 is driven with maximum power efficiency in order to output the braking/driving torque T based on the target torque T ^* . On the other hand, the "upper limit of consumable power" refers to the output of the braking/driving torque T based on the target torque T ^* by adjusting the voltage applied to the drive motor 18 and/or the current flowing through the drive motor 18. The maximum amount of power that can be consumed while maintaining Further, "additionally" refers to an increase in the power consumption of the drive motor 18 when driven with maximum power efficiency. That is, the consumable power Pcd of the drive motor 18 represents the surplus power that can be consumed by the drive motor 18.

When the temperature of the drive motor 18 and/or the inverter 16 is obtained as vehicle information, the first consumable power calculation unit 46 can use these temperatures to more accurately calculate the consumable power Pcd of the drive motor 18.

The second consumable power calculation unit 47 calculates an upper limit value of consumable power in the generator motor 24 (hereinafter referred to as the consumable power ) Pcg is calculated.

The "upper limit of power that can be consumed" by the generator motor 24 refers to the maximum power that can be consumed by the generator motor 24 without causing fluctuations in the rotation speed N _E of the engine 21 that inputs combustion torque to the generator motor 24, by adjusting the voltage applied to the generator motor 24 and/or the current flowing through the generator motor 24. In other words, the consumable power Pcg of the generator motor 24 represents the power that can be consumed by the generator motor 24.

When the temperature of the generator motor 24 and/or the inverter 27 is obtained as vehicle information, the second consumable power calculation unit 47 can use these temperatures to more accurately calculate the consumable power Pcg of the generator motor 24.

The target power consumption calculation unit 48 calculates the target power consumption Pcg ^* of the generator motor 24. The target power consumption Pcg ^* of the generator motor 24 is a transient target value of the power to be consumed by the generator motor 24 out of the surplus power generated by the regenerative control. The upper limit value of the target power consumption Pcg ^* of the generator motor 24 is the consumable power Pcg of the generator motor 24. Furthermore, the target power consumption Pcg ^* of the generator motor 24 is determined for each control period and can change over time. The amount of change over time of the target power consumption Pcg ^* is determined so that the follow-up speed δg of the power consumption in the generator motor 24 becomes a predetermined follow-up speed.

5 is an explanatory diagram showing the relationship between the vehicle speed V and the follow-up speed δg of the power consumption in the generator motor 24. As shown in Fig. 5, the follow-up speed δg of the power consumption in the generator motor 24 is set to increase with an increase in the vehicle speed V. In addition, the follow-up speed δg of the power consumption in the generator motor 24 is set to increase as the rotation speed N _E of the engine 21 increases. In addition, the follow-up speed δg of the power consumption in the generator motor 24 is set to be within a range not exceeding the follow-up speed δd of the power consumption in the drive motor 18.

5 is determined in advance based on, for example, an experiment or a simulation, and is stored in advance in the target power consumption calculation unit 48. Therefore, by referring to this map, the target power consumption calculation unit 48 calculates the target power consumption Pcg ^* for the following speed δg based on the vehicle speed V of the electric vehicle 100 and the rotation speed N _E of the engine 21, with the consumable power Pcg of the generator motor 24 as the upper limit.

In Fig. 5, the speed δg of the power consumption of the generator motor 24 is determined by the vehicle speed V of the electric vehicle 100 and the rotation speed N _E of the engine 21, but it may be determined in accordance with either the vehicle speed V or the rotation speed N _E of the engine 21. Also, instead of using the map of Fig. 5, for example, a minimum value (not shown) in the map of Fig. 5 may be used as a fixed value for the speed δg of the power consumption of the generator motor 24.

The target power consumption calculation unit 48 calculates the target power consumption Pcd ^* of the drive motor 18 in addition to calculating the target power consumption Pcg ^* of the generator motor 24 as described above. The target power consumption Pcd ^* of the drive motor 18 is a transient target value of the power consumed by the drive motor 18 out of the surplus power generated by regeneration control. The upper limit of the target power consumption Pcd ^* of the drive motor 18 is the consumable power Pcd of the drive motor 18. Further, the target power consumption Pcd ^* of the drive motor 18 is determined for each control cycle and may change over time.

The target power consumption calculation unit 48 calculates the target power consumption Pcd ^* of the drive motor 18 based on the target regenerative power Preg ^* , the chargeable power ΔP of the battery 14 , and the target power consumption Pcg ^* of the generator motor 24 .

Specifically, in order to calculate the target power consumption Pcd ^* of the drive motor 18, the target power consumption calculation unit 48 first calculates the surplus power Ps generated by the regeneration control. The surplus power Ps is the deviation (Preg ^* - ΔP) between the target regenerative power Preg ^* and the chargeable power ΔP of the battery 14 .

Next, the target power consumption calculation unit 48 calculates the deviation (Ps-Pcg ^* ) between the surplus power Ps and the target power consumption Pcg ^* of the generator motor 24, and sets this as the target power consumption Pcd ^* of the drive motor 18. The target power consumption calculation unit 48 then sets the tracking speed δd of the drive motor 18 as the tracking speed at which this remaining surplus power is consumed. As a result, as long as the target power consumption Pcd ^* does not exceed the consumable power Pcd, the remaining surplus power (deviation (Ps-Pcg ^* )) excluding the consumption by the generator motor 24 (target power consumption Pcg ^* ) is consumed by the drive motor 18.

That is, assuming that the surplus power Ps is constant, when the target power consumption Pcg ^* of the generator motor 24 decreases, the target power consumption Pcd ^* of the drive motor 18 increases. Therefore, the overall power consumption that is reduced by making the following speed δg of the generator motor 24 slower than the following speed δd of the drive motor 18 is reduced by automatically increasing the following speed δd of the drive motor 18. This is compensated for by increasing the power consumption in motor 18. Similarly, when the target power consumption Pcg ^* of the generator motor 24 increases, the target power consumption Pcd ^* of the drive motor 18 decreases. As a result, the drive motor 18 and the generator motor 24 consume all of the surplus power Ps.

The power consumption follow-up speed δd in the drive motor 18 changes according to the target power consumption Pcg ^* of the power generation motor 24, but the power consumption follow-up speed δg in the power generation motor 24 also takes this change into consideration. It is set to be slower than the power consumption follow-up speed δg.

In addition to the above, the target power consumption calculation unit 48 compares the target regenerative power Preg ^* and the chargeable power ΔP of the battery 14, and based on the comparison result, the target power consumption Pcg ^* of the generator motor 24 and the drive motor 18. Determine whether to increase or decrease target power consumption Pcd ^* . Specifically, when the target regenerative power Preg ^* is larger than the chargeable power ΔP of the battery 14, that is, when surplus power Ps is generated, the target power consumption calculation unit 48 calculates the target power consumption Pcg ^* of the generation motor 24. and the target power consumption Pcd ^* of the drive motor 18 is increased. On the other hand, when the target regenerative power Preg ^* is less than or equal to the chargeable power ΔP of the battery 14, that is, when no surplus power Ps is generated, the target power consumption calculation unit 48 calculates the target power consumption Pcg ^* of the generator motor 24 and the drive motor. 18 target power consumption Pcd ^* is reduced. As described above, the target power consumption Pcg ^* of the power generation motor 24 and the target power consumption Pcd ^* of the drive motor 18 are increased or decreased in accordance with the respective follow-up speeds δg and δd.

(3) Engine Control Unit The engine control unit 33 (see FIG. 2) controls the engine 21 according to the chargeable power ΔP of the battery 14 and the like. Thereby, the engine control unit 33 indirectly drives the power generation motor 24 to generate electric power to be supplied to the battery 14 . In the present embodiment, the engine control unit 33 calculates the target combustion torque Tc ^* of the engine 21 based on the chargeable power ΔP of the battery 14. Target combustion torque Tc ^* is a target value of torque generated by combustion in engine 21. Further, the engine control unit 33 calculates the target combustion torque Tc ^* , and also calculates the target rotation speed Ng ^* of the generator motor 24. The target rotational speed Ng ^* of the generator motor 24 is a target value of the rotational speed Ng of the generator motor 24 when the engine 21 is caused to output the target combustion torque Tc ^* .

The engine control unit 33 controls combustion in the engine 21 by inputting the target combustion torque Tc* to the engine 21. That is, the target combustion torque Tc ^* is a combustion torque command value. Further, the target rotation speed Ng ^* of the generator motor 24 is input to the generator motor controller 35.

(4) Drive Motor Control Unit The drive motor control unit 34 (see FIG. 2) generates a control signal for controlling the drive motor 18 based on the target torque T ^* , the target power consumption Pcd ^* of the drive motor 18, etc. generate.

Figure 6 is a block diagram showing the configuration of the drive motor control unit 34. As shown in Figure 6, the drive motor control unit 34 includes a current calculation unit 51, a rotation speed calculation unit 52, a target current calculation unit 55, a d-axis current deviation calculation unit 56, a d-axis current feedback control unit 57 (FB), a q-axis current deviation calculation unit 58, a q-axis current feedback control unit 59 (FB), and a voltage command calculation unit 60.

The current calculation unit 51 obtains the currents I1u, I1v, and I1w flowing through the drive motor 18 from the current detector 17, and calculates the d-axis current I1d and the q-axis current I1q from these currents I1u, I1v, and I1w using the rotation speed Nd of the drive motor 18. The d-axis current I1d is input to the d-axis current deviation calculation unit 56, and the q-axis current I1q is input to the q-axis current deviation calculation unit 58.

The rotation speed calculation unit 52 obtains the electrical angle θd of the drive motor 18 from the electrical angle detector 19, and calculates the rotation speed Nd of the drive motor 18 based on the obtained electrical angle θd. In the drive motor control section 34 , the rotation speed Nd of the drive motor 18 is input to a target current calculation section 55 .

The target current calculation unit 55 calculates a target d-axis current I1d ^* and a target q-axis current I1q ^* based on the target power consumption Pcd ^* of the drive motor 18, the target torque T ^* , and the current rotation speed Nd of the drive motor 18. The target d-axis current I1d ^* is a target value of the d-axis current I1d in the drive motor 18. Similarly, the target q-axis current I1q ^* is a target value of the q-axis current I1q in the drive motor 18. The target d-axis current I1d ^* is input to the d-axis current deviation calculation unit 56, and the target q-axis current I1q ^* is input to the q-axis current deviation calculation unit 58.

As described above, the target current calculation unit 55 calculates the target d-axis current I1d by considering not only the target torque T ^* and the current rotational speed Nd of the drive motor 18, but also the target power consumption Pcd ^* of the drive motor 18. ^* and target q-axis current I1q ^* are calculated. Therefore, when surplus power Ps is generated by regenerative control, target d-axis current I1d ^* and/or target q-axis current I1q ^* are set to larger values than in normal times when surplus power Ps is not generated. However, the target d-axis current I1d ^* and the target q-axis current I1q ^* are within a range in which the braking/driving torque generated at the drive wheels 10 substantially matches the target torque T ^* (according to the type of electric vehicle 100, etc.). set within the range obtained). Since the drive motor 18 is controlled based on the target d-axis current I1d ^* and the target q-axis current I1q ^* , when surplus power Ps is generated due to regeneration control, at least a part of the surplus power Ps is consumed by the drive motor 18. Ru.

The d-axis current deviation calculation unit 56 calculates the deviation ΔI1d (=I1d ^* −I1d) between the target d-axis current I1d ^* and the current d-axis current I1d. This deviation ΔI1d is input to the d-axis current feedback control unit 57.

The d-axis current feedback control unit 57 feedback controls the d-axis current I1d of the drive motor 18 based on the deviation ΔI1d. As a result, the d-axis current feedback control unit 57 inputs a d-axis current command related to the d-axis current I1d of the drive motor 18 to the voltage command calculation unit 60.

The q-axis current deviation calculation unit 58 calculates the deviation ΔI1q (=I1q ^* −I1q) between the target q-axis current I1q ^* and the current q-axis current I1q. This deviation ΔI1q is input to the q-axis current feedback control section 59.

The q-axis current feedback control unit 59 feedback controls the q-axis current I1q of the drive motor 18 based on the deviation ΔI1q. As a result, the q-axis current feedback control unit 59 inputs a q-axis current command related to the q-axis current I1q of the drive motor 18 to the voltage command calculation unit 60.

The voltage command calculation unit 60 converts the above d-axis current command and q-axis current command into a voltage command by a predetermined calculation, and outputs it to the inverter 16. As a result, the drive motor 18 connected to the inverter 16 is controlled so as to generate a target torque T ^* at the drive wheels 10. The voltage command calculated by the voltage command calculation unit 60 is a command that specifies the voltage to be applied to each phase of the drive motor 18.

(5) Generator Motor Control Unit The generator motor control unit 35 (see FIG. 2) generates a control signal for controlling the generator motor 24 based on the target rotation speed Ng ^* of the generator motor 24 and the target power consumption Pcg ^* of the generator motor 24, etc.

FIG. 7 is a block diagram showing the configuration of the generator motor control section 35. As shown in FIG. As shown in FIG. 7, a current calculation section 61, a rotation speed calculation section 62, a rotation speed deviation calculation section 63, a rotation speed feedback control section 64, a target current calculation section 65, a d-axis current deviation calculation section 66, a d-axis current feedback It includes a control section 67, a q-axis current deviation calculation section 68, a q-axis current feedback control section 69, and a voltage command calculation section 70.

The current calculation unit 61 obtains the currents I2u, I2v, and I2w flowing through the generator motor 24 from the current detector 26, and calculates the d-axis current I2d and the q-axis current I2q from these currents I2u, I2v, and I2w using the rotation speed Ng of the generator motor 24. The d-axis current I2d is input to the d-axis current deviation calculation unit 66, and the q-axis current I2q is input to the q-axis current deviation calculation unit 68.

The rotational speed calculation unit 62 obtains the electrical angle θg of the generator motor 24 from the electrical angle detector 25, and calculates the rotational speed Ng of the generator motor 24 based on the obtained electrical angle θg. In the generator motor control section 35 , the rotation speed Ng of the generation motor 24 is input to the rotation speed deviation calculation section 63 and the target current calculation section 65 .

The rotational speed deviation calculation unit 63 calculates a deviation ΔNg (=Ng ^* −Ng; not shown) between the target rotational speed Ng ^* and the current rotational speed Ng for the generator motor 24. The deviation ΔNg calculated here is input to the rotation speed feedback control section 64.

The rotation speed feedback control unit 64 performs feedback control of the rotation speed Ng of the generator motor 24 based on the deviation ΔNg. As a result, the rotation speed feedback control unit 64 inputs a rotation speed command related to the rotation speed Ng of the generator motor 24 to the target current calculation unit 65. The rotation speed command in the control of the generator motor 24 corresponds to the target torque T ^* in the control of the drive motor 18. That is, the target current calculation unit 55 of the drive motor control unit 34 uses the target torque T ^* of the drive motor 18, but the generator motor 24, which is not used for driving, does not have a target torque. For this reason, the target current calculation unit 65 uses a rotation speed command instead of the target torque T ^* of the drive motor 18.

The target current calculation unit 65 calculates a target d-axis current I2d* and a target q-axis current I2q* based on the target power consumption Pcg ^* of the generator motor 24, the rotation speed command input from the rotation speed feedback control ^{unit 64, and the current rotation speed Ng of the generator motor 24. The target d-axis current I2d* is a} target value of the d-axis current I2d to be passed through the generator motor 24. Similarly, the target q-axis current I2q ^* is a target value of the q-axis current I2q to be passed through the generator motor 24.

As described above, the target current calculation unit 65 calculates the target d-axis current I2d ^* and the target q-axis current I2q ^* in consideration of not only the rotation speed command and the current rotation speed Ng of the generator motor 24 but also the target power consumption Pcg ^* of the generator motor 24. Therefore, when surplus power Ps is generated by the regenerative control, the target d-axis current I2d ^* and/or the target q-axis current I2q ^* are set to values larger than those in normal times when surplus power Ps is not generated. However, the target d-axis current I2d ^* and the target q-axis current I2q ^* are set within a range in which the rotation speed N _E of the engine 21 does not substantially change (a range that is acceptable depending on the type of the electric vehicle 100, etc.). Since a current corresponding to the target d-axis current I2d ^* and the target q-axis current I2q ^* flows through the generator motor 24, when surplus power Ps is generated by the regenerative control, at least a part of the surplus power Ps is consumed by the generator motor 24.

The d-axis current deviation calculation unit 66 calculates the deviation ΔI2d (=I2d ^* −I2d) between the target d-axis current I2d ^* and the current d-axis current I2d. This deviation ΔI2d is input to the d-axis current feedback control unit 67.

The d-axis current feedback control unit 67 feedback controls the d-axis current I2d of the generator motor 24 based on the deviation ΔI2d. As a result, the d-axis current feedback control unit 67 inputs a d-axis current command related to the d-axis current I2d of the generator motor 24 to the voltage command calculation unit 70.

The q-axis current deviation calculation unit 68 calculates the deviation ΔI2q (=I2q ^* −I2q) between the target q-axis current I2q ^* and the current q-axis current I2q. This deviation ΔI2q is input to the q-axis current feedback control unit 69.

The q-axis current feedback control unit 69 feedback-controls the q-axis current I2q of the generator motor 24 based on the deviation ΔI2q. As a result, the q-axis current feedback control unit 69 inputs a q-axis current command regarding the q-axis current I2q of the generator motor 24 to the voltage command calculation unit 70.

The voltage command calculation unit 70 converts the above d-axis current command and q-axis current command into a voltage command by a predetermined calculation, and outputs it to the inverter 27. As a result, currents corresponding to the d-axis current command and the q-axis current command flow through the generator motor 24 connected to the inverter 27. The voltage command calculated by the voltage command calculation unit 70 is a command that specifies the voltage to be applied to each phase of the generator motor 24.

FIG. 8 is an explanatory diagram showing a method of adjusting power consumption in the drive motor 18 and the power generation motor 24. The d-axis current Id and the q-axis current Iq in FIG. They are a current I2d and a q-axis current I2q. Further, the current vector I _total in FIG. 8 is a composite vector of the d-axis current Id and the q-axis current Iq, and represents the amount of current flowing through the drive motor 18 or the generator motor 24.

In controlling the drive motor 18 and the generator motor 24, when comparing the correlations (torque correlations) between the d-axis current Id and the q-axis current Iq and the output torque, the q-axis current Iq has a large torque correlation, and the d-axis current Id has a small torque correlation. That is, when the q-axis current Iq changes, the torque output by the drive motor 18 and the generator motor 24 changes significantly. On the other hand, when the d-axis current Id changes, the change in the torque output by the drive motor 18 and the generator motor 24 is small. Therefore, as shown in FIG. 8, if the d-axis current Id is increased to the d-axis current Id' without changing the q-axis current Iq, and the current vector I _total is extended to I' _total , the power consumption can be increased while keeping the output torque roughly constant. That is, by mainly adjusting the d-axis current Id, the power efficiency of the drive motor 18 and the generator motor 24 can be adjusted without changing the output torque.

Therefore, when surplus power Ps is generated, the target current calculation unit 55 (see FIG. 6) increases, for example, the target d-axis current I1d ^* based on the target power consumption Pcd ^* of the drive motor 18, and increases the current vector. The size is set to correspond to the target power consumption Pcd ^* of the drive motor 18. As a result, the braking/driving torque generated at the drive wheels 10 falls within a range that substantially matches the target torque T ^* , and the target power consumption Pcd ^* of the drive motor 18 is achieved. Similarly, when surplus power Ps is generated, the target current calculation unit 65 (see FIG. 7) increases, for example, the target d-axis current I2d ^* based on the target power consumption Pcg ^* of the generator motor 24, and increases the current vector is set to a size corresponding to the target power consumption Pcg ^* of the generator motor 24. As a result, the rotational speed N _E of the engine 21 remains within a range that does not substantially change, and the target power consumption Pcg ^* of the generator motor 24 is achieved.

Hereinafter, the effect of regeneration control in electric vehicle 100 configured as described above will be explained.

Figure 9 is a flowchart showing the operation of the electric vehicle 100 according to the first embodiment. As shown in Figure 9, in the regenerative control executed by the electric vehicle 100, first, in step S101, vehicle information required for control, such as the accelerator opening Apo, is detected. In step S102, the vehicle speed V, etc. is detected. In step S102, other required vehicle information is detected by calculation, etc., using the detected vehicle information, such as the accelerator opening Apo.

Next, in step S103, a target regenerative braking torque, which is a target torque T ^* during regenerative control, is calculated. In addition, in step S104, a target regenerative power Preg ^* is calculated, and in step S105, a chargeable power ΔP is calculated. Furthermore, in step S106, a consumable power Pcg of the generator motor 24, which is a non-driving motor, is calculated, and in step S107, a consumable power Pcd of the driving motor 18 is calculated.

After that, in step S108, target regenerative power Preg ^* and chargeable power ΔP are compared. As a result of this comparison, when the target regenerative power Preg ^* is larger than the chargeable power ΔP and surplus power Ps is generated by the regeneration control, steps S109 and S110 are executed. On the other hand, as a result of the comparison in step S108, if the target regenerative power Preg ^* is less than or equal to the chargeable power ΔP, the regenerative power can be recovered by the battery 14, and no surplus power Ps is generated, steps S111 and S112 are executed. .

In step S109, a target power consumption Pcg ^* corresponding to the generation or increase/decrease of surplus power Ps is calculated for the generator motor 24, which is a non-driving motor. In addition, in step S110, a target power consumption Pcd ^* corresponding to the generation or increase/decrease of surplus power Ps is calculated for the driving motor 18. These target power consumption Pcg ^* and target power consumption Pcd ^* are set so that the rate of increase in power consumption in the generator motor 24 (tracking speed δg) is slower than the rate of increase in power consumption in the driving motor 18 (tracking speed δd).

On the other hand, in step S111, a target power consumption Pcg ^* is calculated to reduce the power consumption of the generator motor 24, which is a non-driving motor, at a tracking speed δg similar to that in step S109. In addition, in step S112, a target power consumption Pcd ^* is calculated to reduce the power consumption of the driving motor 18 at a tracking speed δd similar to that in step S110. This is to suppress abrupt changes in the number of revolutions Ng of the generator motor 24, the number of revolutions N _E of the engine 21, and the number of revolutions Nd of the driving motor 18 even when the surplus power Ps is suddenly no longer generated, for example, when the regenerative control is switched to the driving control by depressing the accelerator. The target power consumption Pcd ^* in this case is for making the additional power consumption for consuming the surplus power Ps in the generator motor 24 approach zero.

In this way, when the target power consumption Pcg ^* of the generator motor 24 and the target power consumption Pcd ^* of the drive motor 18 are calculated, in step S113, the rate of change with respect to the target regenerative braking torque, which is the target torque T ^* during regeneration control, is calculated. Restriction processing such as restriction is performed. After that, in step S114, the generation motor 24, which is a non-drive motor, is controlled based on the target power consumption Pcg ^* of the generation motor 24, and the generation motor 24, which is a non-drive motor, is controlled based on the target power consumption Pcd ^* of the drive motor 18 and the target regenerative braking torque after the restriction process. The drive motor 18 is controlled accordingly.

By operating as described above, in the electric vehicle 100, when surplus power Ps is generated by regenerative control, this surplus power Ps is consumed by the drive motor 18 and the generator motor 24. Then, in response to the generation or increase/decrease of surplus power Ps, the tracking speed δg of the power consumption in the generator motor 24, which is a non-drive motor, is adjusted to be slower than the tracking speed δd of the power consumption in the drive motor 18.

FIG. 10 is a timing chart showing changes in (A) braking/driving torque of the drive motor 18, (B) surplus power Ps, and (C) power consumption when the electric vehicle 100 decelerates.

For example, electric vehicle 100 is accelerated at a constant acceleration from time t0 to time t1, and thereafter, electric vehicle 100 is decelerated by regenerative control torque generated by drive motor 18 from time t1, and electric vehicle 100 is accelerated at time t6. Let's say it comes to a stop. More specifically, as shown in FIG. 10(A), the torque of the drive motor 18 is a constant positive value from time t0 to time t1, and a drive torque that accelerates the electric vehicle 100 is generated at the drive wheels 10. do. Then, the torque of the drive motor 18 decreases from time t1 to time t2, and regenerative braking torque is generated at the drive wheels 10. Between time t1 and time t2, the braking/driving torque of the drive motor 18 becomes negative. Furthermore, since the torque of drive motor 18 is constant from time t2 to time t3, electric vehicle 100 is decelerated by constant regenerative braking torque. After that, the driving torque gradually increases until time t6, and becomes zero at time t6. Further, assume that when electric vehicle 100 is decelerated by regenerative braking torque after time t1, surplus electric power Ps is generated as shown in FIG. 10(B).

At this time, in the electric vehicle 100, the surplus power Ps generated by the regeneration control is consumed by the drive motor 18 and the generator motor 24, but the drive motor 18 and the generator motor 24 consume the surplus power Ps for generation or increase/decrease. The power follow-up speed is different. Specifically, as shown in FIG. 10(C), surplus power Ps is generated from time t1, and increases toward time t2. As shown in the broken line graph 71, the following speed δd of the power consumption in the drive motor 18 is agile with respect to the generation and increase of the surplus power Ps. On the other hand, as shown in the solid line graph 72, for the same generation and increase of surplus power Ps, the power consumption follow-up speed δg in the generation motor 24 becomes slower than the power consumption follow-up speed δd in the drive motor 18. It is adjusted as follows.

This also applies when the surplus power Ps decreases. That is, when the surplus power Ps begins to decrease from time t2, as shown in the graph 71, the power consumption in the drive motor 18 immediately begins to decrease in response to this, and reaches zero at time t4. On the other hand, as shown in the graph 72, the power consumption in the generator motor 24 is delayed and starts to decrease from time t3, which is after time t2, and the rate of decrease is as follows: slower than the rate of power decline.

In this way, when the surplus power Ps generated by regenerative control is consumed by the drive motor 18 and the generator motor 24, a regenerative braking torque that meets the requirements can be obtained even when only a small regenerative braking torque is normally obtained, such as when the battery 14 is nearly fully charged. In particular, although the generator motor 24 alone may not be able to consume all of the surplus power Ps, the drive motor 18 and the generator motor 24 are used together to consume the surplus power Ps, so that a regenerative braking torque that meets the requirements can be stably obtained, even when the battery 14 is nearly fully charged.

In addition, since the following speed δg of the generator motor 24 is slower than the following speed δd of the drive motor 18, deterioration of sound and vibration performance is prevented. For example, if the surplus power Ps can be consumed, regenerative braking torque that satisfies the demand can be obtained, so if the power consumption in the generator motor 24 is made to steeply follow the generation and increase/decrease of the surplus power Ps, the engine connected to the generator motor 24 The rotational speed N _E of No. 21 also suddenly changes accordingly, and the sound and vibration performance deteriorates. Therefore, by making the following speed δg of the generator motor 24 slower than the following speed δd of the drive motor 18, sudden changes in the rotational speed N _E of the engine 21 are prevented. As a result, even when the battery 14 is nearly fully charged, regenerative braking torque that satisfies the requirements can be obtained while maintaining sound and vibration performance.

In addition, since the following speed δg of the generator motor 24 is slower than the following speed δd of the drive motor 18, the generator motor 24 can be prevented from overheating. For example, when surplus power Ps is generated, the SOC of the battery 14 is often close to full charge, and the engine 21 and the generator motor 24 are stopped. In this way, if an additional current is applied to the stopped generator motor 24 within a range in which the rotation speed N _E of the engine 21 remains almost unchanged, the current may flow intensively through some of the windings of the generator motor 24, resulting in overheating. However, by slowing down the following speed δg of the generator motor 24, the amount of heat generated is reduced. In other words, by slowing down the following speed δg of the generator motor 24 compared to the following speed δd of the drive motor 18, it is possible to obtain a regenerative braking torque that satisfies the requirements while preventing the generator motor 24 from overheating, even when the battery 14 is close to full charge. In addition, when the follow-up speed δg of the generator motor 24 is slowed down, the fluctuation in the rotation speed N _E of the engine 21 is reduced when the engine 21 is subsequently switched to motoring. As a result, even when the battery 14 is nearly fully charged, a regenerative braking torque that satisfies the requirements can be obtained while maintaining the sound and vibration performance.

In addition, since Fig. 10 shows, as an example, the process of coming to a stop by continuous regenerative control, the surplus power Ps does not suddenly disappear (become zero) after it is generated, regardless of consumption by the drive motor 18 and the generator motor 24. However, after the start of regenerative control, for example, when the accelerator is depressed, the surplus power Ps may suddenly disappear accordingly. In such a case, the operations of steps S111 and S112 suppress abrupt changes in the rotation speed Ng of the generator motor 24, the rotation speed N _E of the engine 21, and the rotation speed Nd of the drive motor 18. As a result, the sound vibration performance is maintained.

As described above, the regenerative control method according to the first embodiment is a regenerative control method for an electric vehicle 100 including a drive motor 18 used for drive control that generates drive torque on the drive wheels 10 by power supply from the battery 14 and regenerative control that recovers power to the battery 14 and generates regenerative braking torque on the drive wheels 10, and a non-drive motor (generator motor 24) that is driven by the engine 21 to supply power to the battery 14. In this regenerative control method, regenerative power (target regenerative power Preg ^* ), which is power generated to obtain regenerative braking torque, is calculated, and a chargeable power ΔP of the battery 14 is calculated. In this regenerative control method, when surplus power Ps is generated by the regenerative control due to at least the regenerative power (target regenerative power Preg ^* ) exceeding the chargeable power ΔP, the surplus power Ps is consumed by the drive motor 18 and the non-drive motor (generator motor 24). Furthermore, in this regenerative control method, the speed δg of the power consumption of the non-driving motor (the generator motor 24 ) responding to the generation or increase/decrease of the surplus power Ps is made slower than the speed δd of the power consumption of the driving motor 18 responding to the generation or increase/decrease of the surplus power Ps.

This suppresses the rate of change in the rotation speed N _E of the engine 21 connected to the non-driven motor (generator motor 24) compared to when the power consumption of the non-driven motor (generator motor 24) is maximized to consume the surplus power Ps. Also, even if a current flows through some of the windings of the non-driven motor (generator motor 24) to consume the surplus power Ps, the peak of this current is reduced. Therefore, compared to when the power consumption of the non-driven motor (generator motor 24) is instantly maximized to consume the surplus power Ps, the amount of heat generated in the some of the windings is suppressed. As a result, the required regenerative braking torque can be obtained while preventing deterioration of the sound and vibration performance and overheating of the non-driven motor (generator motor 24).

Furthermore, in the regeneration control method according to the first embodiment, the power consumption of the drive motor 18 and the non-drive motor (generation motor 24) is adjusted so as to maintain their torques. As a result, the drive motor 18 can maintain a regeneration control torque that almost matches the demand, and the non-drive motor (generator motor 24) can suppress fluctuations in the rotational speed N _E of the engine 21. Improved controllability.

Furthermore, when the following speed δg of the non-drive motor (generating motor 24) is made slower than the following speed δd of the drive motor 18, the total amount of power consumption in the drive motor 18 and the non-driving motor (generating motor 24) is usually reduced. . However, in the regeneration control method according to the first embodiment, the power consumption that is insufficient due to the following speed δg of the non-drive motor (generating motor 24) being made slower than the following speed δd of the drive motor 18 is reduced by the following speed of the drive motor 18. It is consumed by increasing the speed δd and increasing the power consumption in the drive motor 18. Therefore, as long as the power consumption in the drive motor 18 does not exceed the limit (consumable power Pcd) of the drive motor 18, the surplus power Ps can be consumed by the drive motor 18 and the non-drive motor (generating motor 24). As a result, under normal driving conditions, the required regenerative braking torque can almost always be obtained regardless of the SOC of the battery 14. Furthermore, according to this control, more surplus power Ps is transferred to the drive motor 18 and the non-drive motor (generator motor 24) than when the power consumption of the non-drive motor (generator motor 24) is simply reduced. ) can be consumed. As a result, the maximum regenerative braking torque that can be generated by the drive motor 18 increases.

More specifically, in the regeneration control method according to the first embodiment, the power consumption (target power consumption Pcg ^* ) in the non-drive motor (generation motor 24) is determined, and out of the generated surplus power Ps, the power consumption for the non-drive motor is determined. The remaining surplus power (Ps-Pcg ^* ) after removing the consumption (target power consumption Pcg ^* ) of the motor (generating motor 24) is calculated. Then, the follow-up speed δd of the drive motor 18 is set to a follow-up speed that consumes the remaining surplus power (Ps-Pcg ^* ). Thereby, the power consumption that is insufficient due to the follow-up speed δg of the non-drive motor (generating motor 24) being made slower than the follow-up speed δd of the drive motor 18 is automatically compensated for. Therefore, in the regeneration control method according to the first embodiment, the surplus electric power Ps is consumed by the drive motor 18 and the non-drive motor (generator motor 24), and the required regenerative braking torque is easily obtained.

In addition to the above, in the regenerative control method according to the first embodiment, the following speed δg of the non-driven motor (the generator motor 24) is determined based on the vehicle speed V of the electric vehicle 100 and/or the rotation speed N _E of the engine 21. Therefore, the following speed δg of the non-driven motor (the generator motor 24) can be appropriately set according to the driving conditions. In this way, the following speed δg is appropriately adjusted according to the driving conditions, which makes it easier to perform regenerative control appropriately.

More specifically, in the regeneration control method according to the first embodiment, the higher the vehicle speed V, the higher the follow-up speed δg of the non-drive motor (generator motor 24). This is because the higher the vehicle speed V, the greater the so-called background noise such as running sound, so even if the sound and vibration performance deteriorates somewhat due to fluctuations in the rotational speed N _E of the engine 21, it can be tolerated. . In this manner, by increasing the follow-up speed δg of the non-drive motor (generator motor 24) as the vehicle speed V increases, regeneration control is likely to be performed appropriately, especially under driving conditions where the vehicle speed V is high.

Moreover, in the regenerative control method according to the first embodiment, the higher the rotation speed N _E of the engine 21, the higher the follow-up speed δg of the non-driven motor (the generator motor 24). The reason for setting in this manner is that the higher the rotation speed N _E of the engine 21, the greater the sound vibration, so even if the sound vibration performance deteriorates slightly due to fluctuations in the rotation speed N _E of the engine 21, it is acceptable. In this manner, by setting the follow-up speed _δg of the non-driven motor (the generator motor 24) higher as the rotation speed N _{E of the engine 21 increases, regenerative control is likely to be performed appropriately, particularly under operating conditions where the rotation speed N E} of the engine 21 is high.

[Second embodiment]
In the first embodiment, the following speed δg of the generator motor 24 is determined regardless of torque fluctuations due to combustion in the engine 21 (see FIG. 5). It is preferable to take into account torque fluctuations due to combustion. In this embodiment, an example will be described in which the following speed δg of the generator motor 24 is determined in consideration of torque fluctuations due to combustion in the engine 21.

FIG. 11 is a flowchart of determination processing added in the second embodiment. As shown in FIG. 11, in this embodiment, when determining the following speed δg of the generator motor 24, it is determined in step S201 whether the engine 21 is in the middle of warm-up operation (warming up). Ru. If the result of the determination in step S201 is that the engine 21 is warming up, step S202 is executed. On the other hand, if the result of the determination in step S201 is that the engine 21 is not warming up, step S204 is executed.

In step S202, it is determined whether the engine 21 is in transition. During a transition is a state in which the rotational speed N _E of the engine 21 is transitioned from a predetermined rotational speed N _E to another rotational speed for warm-up, or the rotational speed N _E of the engine 21 is changed during that process. A state in which the is changing. When the engine 21 is in transition, step S203 is executed. On the other hand, when the engine 21 is not in transition, step S204 is executed.

In step S203, the follow-up speed δg of the non-drive motor (generator motor 24) is further reduced from the follow-up speed δg defined in the first embodiment (see FIG. 5). In a scene where the engine 21 is warming up and in transition, the torque fluctuation of the engine 21 is noticeable. For this reason, when the follow-up speed δg of the non-driving motor (generating motor 24) is high, the sound vibration performance is particularly likely to deteriorate. Therefore, in step S203, in a scene where the torque fluctuation of the engine 21 is significant, the following speed δg of the non-drive motor (generator motor 24) is reduced compared to normal. The reduction in the following speed δg in step S203 is performed, for example, by replacing the map that defines the following speed δg in FIG. 5 with a map that defines a lower following speed δg. Moreover, by adding a limit to the following speed δg defined in the map of FIG. 5 by a predetermined upper limit value, the following speed δg can be reduced.

In step S204, the following speed δg of the non-driven motor (generator motor 24) is maintained at the following speed δg (see FIG. 5) defined in the first embodiment. When the engine 21 is not warming up, or when the engine 21 is warming up but not in a transitional state, the torque fluctuation of the engine 21 is no different from that during normal operation. For this reason, in step S204, the following speed δg of the non-driven motor (generator motor 24) is maintained.

FIG. 12 shows changes in (A) braking/driving torque of the drive motor 18, (B) surplus power Ps, and (C) power consumption when the electric vehicle 100 decelerates in a situation where the torque fluctuation of the engine 21 is large. This is a timing chart. As shown in FIGS. 12(A) and 12(B), the situation in which the electric vehicle 100 attempts to stop is the same as in the first embodiment. On the other hand, as shown in FIG. 12(C), when the torque fluctuation of the engine 21 is large by performing the above determination process, as shown in the solid line graph 81, the following speed δg of the generator motor 24 is changed to the first This is further reduced than in the embodiment (see graph 71 in FIG. 10(C)). Accordingly, as shown in a broken line graph 82, the follow-up speed δd of the drive motor 18 becomes higher than in the first embodiment (see graph 72 in FIG. 10(C)).

As described above, in the regeneration control method according to the second embodiment, the following speed δg of the generator motor 24 is reduced in a scene where the torque fluctuation of the engine 21 is large. Thereby, even in a scene where the torque fluctuation of the engine 21 is large, the required regenerative braking torque can be obtained while particularly appropriately preventing deterioration of the sound and vibration performance.

In the above example of the second embodiment, the scene where the torque fluctuation of the engine 21 is large is particularly a scene where the engine 21 is warming up and the rotation speed N _E of the engine 21 is changed from a predetermined rotation speed. This is a scene where the torque fluctuation of the engine 21 is particularly likely to be large. Therefore, in this scene, if the follow-up speed δg of the non-driving motor (the generator motor 24) is further slowed, the required regenerative braking torque can be obtained while particularly appropriately preventing deterioration of the sound vibration performance.

In the second embodiment, the determination of whether the engine 21 is warming up in step S201 and the determination of whether the engine 21 is in a transition state in step S202 are combined to determine whether the torque fluctuation of the engine 21 is large, but this is not limited to the above. For example, the determination of whether the engine 21 is warming up in step S201 may be omitted, and the determination of whether the engine 21 is in a transition state in step S202 may be used to determine whether the engine 21 is in a transition state. However, in the electric vehicle 100, the generator motor 24 is driven at a predetermined rotation speed that provides good power generation efficiency during operation, except during warming up. In addition, it is easier to determine whether the engine 21 is warming up than whether the engine 21 is in a transition state. For this reason, as in the example of the second embodiment, the load of calculations, etc. is reduced by determining whether the engine 21 is in a transition state only when the engine 21 is warming up.

[Third embodiment]
In the first and second embodiments described above, the following speed δg of the non-driven motor (the generator motor 24) changes in response to the vehicle speed V, but increases monotonically as the vehicle speed V increases, regardless of the speed range of the vehicle speed V (see FIG. 5). However, the manner in which the following speed δg is changed in response to the vehicle speed V can be set more flexibly and arbitrarily. For example, in this embodiment, a correction process is performed in which an upper limit value in response to the vehicle speed V is further set to the following speed δg of the generator motor 24 calculated in the first embodiment.

Figure 13 is a graph showing the correction process applied to the tracking speed δg of the power consumption of the generator motor 24 in the third embodiment. As shown in Figure 13, in this embodiment, in the range where the vehicle speed V is equal to or less than a predetermined threshold value Th1, the tracking speed δg of the generator motor 24 is limited to a fixed upper limit value "δg0". In addition, in the range where the vehicle speed V is greater than the threshold value Th1, this upper limit value is increased from the fixed upper limit value "δg0" as the vehicle speed V increases. Then, the tracking speed δg of the generator motor 24 calculated in the first embodiment is limited or expanded by the upper limit value shown in Figure 13.

The threshold value Th1 is determined in advance, for example, based on the background noise generated by the running of the electric vehicle 100 and the sound vibration performance that is acceptable depending on the type of the electric vehicle 100. In addition, the certain upper limit value "δg0" is determined in advance by experiments, etc., based on the safety against overheating of the generator motor 24 and the sound vibration performance that is acceptable depending on the type of the electric vehicle 100.

As described above, in the regenerative control method according to the third embodiment, the following speed δg of the non-driven motor (generator motor 24) when the vehicle speed V is greater than a predetermined threshold value Th1 is set to be greater than the following speed δg (constant value "δg0") of the non-driven motor (generator motor 24) when the vehicle speed V is equal to or less than the threshold value Th1. This makes it possible to speed up the response of the maximum regenerative braking torque when the vehicle speed V is high and deterioration of sound and vibration performance is not a major problem. Also, when the vehicle speed V is low, the required regenerative braking torque is obtained while satisfying the sound and vibration performance required according to the type of electric vehicle 100.

[Fourth embodiment]
As described above, motoring may be performed in the electric vehicle 100. In motoring, the generator motor 24 is driven in such a manner that the torque of the generator motor 24 is changed by the power supply from the battery 14. As a result, the engine 21 is idling. In this way, the power of the battery 14 is used in motoring, so that the generation of surplus power Ps due to regenerative control can be suppressed. Therefore, in this embodiment, the consumption of surplus power Ps in the drive motor 18 and the generator motor 24 in the first embodiment and the like, and the use of motoring will be described.

Figure 14 is a flowchart of the judgment process added in the fourth embodiment. As shown in Figure 14, in this embodiment, in step S301, it is judged whether or not quietness should be prioritized. A situation in which quietness should be prioritized is, for example, a situation in which the vehicle speed V is low (for example, the vehicle speed V is lower than the threshold value Th1 in the third embodiment). In addition, for example, a situation in which quietness should be prioritized is also a situation in which the EV mode (electric vehicle mode) in which the engine 21 is not used and the electric vehicle 100 is driven within the range of the power of the battery 14 is set as the driving mode.

When it is determined in step S301 that the situation requires priority for quietness, step S302 is executed. In step S302, as in the first embodiment, the power consumption of the non-driving motor (the generator motor 24) and the driving motor 18 is increased. That is, in step S302, motoring is prioritized, and instead of performing motoring (e.g., without motoring or by stopping motoring), the surplus power Ps generated by regenerative control is consumed by the driving motor 18 and the generator motor 24. Therefore, at least a portion of the surplus power Ps is consumed by the generator motor 24 while maintaining the torque of the generator motor 24, for example, by adjusting the d-axis current.

On the other hand, when it is determined in step S301 that the situation does not require priority given to quietness, step S303 is executed. In step S303, instead of consuming the surplus power Ps in the drive motor 18 and the generator motor 24 as in the first embodiment, motoring is performed and the generation of surplus power Ps itself is suppressed using the power of the battery 14. That is, in step S303, motoring is prioritized.

As described above, in the regenerative control method according to the fourth embodiment, when the vehicle speed V of the electric vehicle 100 is smaller than a predetermined threshold (e.g., threshold Th1) or when control is being performed in a driving mode (EV mode) in which quietness is prioritized, instead of performing motoring, at least a portion of the surplus power Ps is consumed by the non-drive motor (generator motor 24) while maintaining the torque of the non-drive motor (generator motor 24) by, for example, adjusting the d-axis current of the non-drive motor (generator motor 24). In this way, by appropriately using the control of consuming the surplus power Ps by the drive motor 18 and the non-drive motor (generator motor 24) and the control of using the power of the battery 14 by motoring, the frequency of execution of the control of consuming the surplus power Ps by the drive motor 18 and the non-drive motor (generator motor 24) is reduced. As a result, heat generation in the drive motor 18 and the non-drive motor (generator motor 24) is suppressed.

[Fifth embodiment]
In the first embodiment and the like described above, the friction brake 28 is not controlled by the controller 12, but by controlling the friction brake 28 by the controller 12, the friction brake 28 can be used in combination with regeneration control. In this case, the controller 12 calculates the amount of heat generated by the drive motor 18 and the non-drive motor (generator motor 24) when the surplus power Ps is consumed by the drive motor 18 and the non-drive motor (generator motor 24). Then, the friction brake 28 is operated according to the calculated amount of heat of each motor. For example, when the amount of heat generated by the drive motor 18 exceeds a predetermined threshold H1 (not shown), or when the amount of heat generated by the generator motor 24 exceeds a predetermined threshold H2 (not shown), the controller 12 Activate the friction brake 28. Then, the controller 12 limits the current flowing through the drive motor 18 and/or the non-drive motor (generator motor 24) to limit power consumption so that the amount of heat generated is within the threshold values H1 and H2. The threshold value H1 is predetermined in consideration of the heat resistance of the drive motor 18 and its surrounding members. Similarly, the threshold value H2 is predetermined in consideration of the heat resistance of the generator motor 24 and its surrounding members. Furthermore, the friction braking torque generated by the friction brake 28 is adjusted to achieve the required regenerative braking torque.

In this way, when surplus power Ps is consumed, the amount of heat generated in the drive motor 18 and the non-drive motor (generator motor 24) is calculated, and the friction brake 28 is operated according to the calculated amount of heat, thereby suppressing heat generation in the drive motor 18 and the generator motor 24.

As in the above fifth embodiment, when the controller 12 uses the friction brake 28 in combination with regenerative control, the controller 12 can activate the friction brake 28 when the target power consumption Pcd ^* of the drive motor 18 exceeds the consumable power Pcd. In this way, by activating the friction brake 28 when the target power consumption Pcd ^* of the drive motor 18 exceeds the consumable power Pcd, the required regenerative braking torque can be obtained even when surplus power Ps is generated that cannot be consumed by the drive motor 18 and the non-drive motor (the generator motor 24).

Although the embodiments of the present invention have been described above, the configurations described in the above embodiments and each modification example merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention. do not have. For example, the present invention is suitable for electric vehicles having two or more drive motors and electric vehicles having two or more non-drive motors.

10: Drive wheel 11: Power train 12: Controller 14: Battery 18: Drive motor 21: Engine 24: Generation motor 28: Friction brake 31: Braking/driving torque control section 32: Power consumption control section 33: Engine control section 34: Drive Motor control section 35 : Generation motor control section 41 : Vehicle speed calculation section 42 : Target torque calculation section 43 : Target torque restriction section 44 : Target regenerative power calculation section 45 : Rechargeable power calculation section 46 : First consumable power calculation section 47 :Second consumable power calculation section 48:Target power consumption calculation section

Claims (13)

A regenerative control method for an electric vehicle including a drive motor used in drive control for generating drive torque on drive wheels by power supply from a battery and in regenerative control for recovering power to the battery and generating regenerative braking torque on the drive wheels, and a non-drive motor that is driven by an engine to supply power to the battery, comprising:
Calculating regenerative power, which is power generated to obtain the regenerative braking torque;
Calculating a chargeable power of the battery;
When the regenerative power exceeds the chargeable power and surplus power is generated by the regenerative control, the surplus power is consumed by the drive motor and the non-drive motor;
a speed at which the power consumption of the non-driving motor follows the generation or increase/decrease of the surplus power is slower than a speed at which the power consumption of the driving motor follows the generation or increase/decrease of the surplus power;
Regenerative control method. The regeneration control method according to claim 1,
adjusting the power consumption to maintain the torque of the drive motor and the non-drive motor;
Regeneration control method. The regenerative control method according to claim 1 or 2,
the power consumption that is insufficient due to the following speed of the non-driving motor being slower than the following speed of the driving motor is consumed by increasing the following speed of the driving motor to increase the power consumption of the driving motor.
Regenerative control method. The regeneration control method according to claim 3,
determining power consumption in the non-drive motor;
Calculating the remaining surplus power after excluding the amount consumed by the non-driving motor from the generated surplus power,
the following speed of the drive motor is set to a following speed that consumes the remaining surplus power;
Regeneration control method. The regenerative control method according to claim 4,
The following speed of the non-driving motor is determined based on the vehicle speed of the electric vehicle and/or the rotation speed of the engine.
Regenerative control method. The regenerative control method according to claim 5,
The higher the vehicle speed, the higher the follow-up speed of the non-driving motor is set.
Regenerative control method. The regenerative control method according to claim 5 or 6,
The higher the engine speed, the higher the follow-up speed of the non-driving motor is set.
Regenerative control method. The regeneration control method according to any one of claims 5 to 7,
The following speed of the non-driving motor when the vehicle speed is greater than a predetermined threshold is made larger than the following speed of the non-driving motor when the vehicle speed is less than or equal to the threshold;
Regeneration control method. A regenerative control method according to any one of claims 1 to 8,
In a scene where the torque fluctuation of the engine is large, the following speed of the non-driving motor is further slowed down.
Regenerative control method. The regenerative control method according to claim 9,
The scene in which the torque fluctuation is large is a scene in which the engine is warming up and the engine speed is changed from a predetermined speed.
Regenerative control method. The regeneration control method according to any one of claims 1 to 4,
By driving the non-drive motor in such a manner that the torque of the non-drive motor is changed by power supply from the battery, motoring is performed using the electric power of the battery by idling the engine;
When the vehicle speed of the electric vehicle is lower than a predetermined threshold value, or when control is being performed in a driving mode where priority is given to quietness, instead of performing the motoring, the d-axis of the non-drive motor is consuming at least a portion of the surplus power in the non-drive motor while maintaining the torque of the non-drive motor by adjusting current;
Regeneration control method. The regeneration control method according to any one of claims 1 to 11,
calculating the amount of heat generated in the drive motor and the non-drive motor when consuming the surplus power;
activating a friction brake according to the calculated amount of heat;
Regeneration control method. A drive motor used for drive control that generates drive torque to the drive wheels by supplying power from a battery and regeneration control that recovers power to the battery and generates regenerative braking torque to the drive wheels, and a drive motor that is driven by an engine. A regeneration control device for an electric vehicle, comprising: a non-drive motor that supplies power to the battery; and a controller that controls the drive motor and the non-drive motor;
The controller includes:
Calculating regenerative power, which is the power generated to obtain the regenerative braking torque,
Calculating the chargeable power of the battery,
When surplus power is generated by regeneration control due to at least the regenerated power exceeding the chargeable power, the surplus power is consumed by the drive motor and the non-drive motor;
With respect to the generation or increase/decrease of the surplus power, the following speed of the power consumption in the non-driving motor is made slower than the following speed of the power consumption in the driving motor.
Regeneration control device.