JP3721838B2 - Regenerative power control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a configuration of a regenerative power control device that charges a battery with kinetic energy in an electric vehicle, and more particularly, to an operation that allows a driver to feel comfortable when starting on a slope.
[0002]
[Prior art]
When the car is started uphill, if the component force in the downhill direction of gravity is greater than the driving force (creep) between releasing the brake and stepping on the accelerator, the vehicle will move backward due to acceleration in the downhill direction. . This phenomenon is called rollback. Further, the forward movement in the downhill direction when trying to move backward on the downhill is called roll forward. Both of these means that the vehicle moves in the opposite direction to the desired direction.
[0003]
FIG. 5 is a diagram showing acceleration, speed, and displacement when the electric vehicle starts off a hill.
Here, t = 0 is the time when the brake pedal is released, and t = t1 is the time when the accelerator pedal is depressed.
During 0 ≦ t ≦ t1, the forces acting on the vehicle are only the creep force F and gravity Mg generated by the motor as shown in FIG. When the component force Mgsin θ in the slope direction of gravity Mg is greater than the creep force F, the resultant force is in the negative direction as shown by the solid line in FIG. At this time, the vehicle speed changes and increases in the downhill direction as shown in (b) and the displacement as shown in (c).
[0004]
When the accelerator pedal is depressed at time t1, the driving force generated by the motor increases and the driving force F becomes larger than the component force Mgsinθ in the slope direction of gravity Mg as shown in FIG. As shown in FIG. 5A, the resultant force turns in the positive direction.
The vehicle speed begins to decelerate as shown in (b). The vehicle continues to move backward as shown in (c). When the vehicle speed becomes zero at t2 due to the deceleration, the vehicle turns in the forward direction and starts to climb the hill while the speed increases.
[0005]
While 0 <t ≦ t2 in which the vehicle speed is in the negative direction, the driving force of the motor is in the positive direction as shown by the dotted line in (a), so regenerative power is generated by the motor power generation principle and the battery is charged. . A region where the vehicle speed is negative with respect to a positive driving force is a so-called rollback region.
This will be described with reference to a torque curve diagram for controlling the electric vehicle as follows.
[0006]
FIG. 8 is a torque curve diagram. The right side is the control pattern of the power running area, and the left side is the control pattern of the regeneration area. When the brake is released at t = 0, the motor speed increases in the reverse direction while generating a creeping force on the motor. When the accelerator is stepped on at time t = t1, the motor torque increases in accordance with a predetermined control pattern. When the accelerator torque exceeds the component force in the slope direction of gravity, the reverse is stopped and the vehicle speed changes in the forward direction. After time t = t2, the vehicle speed and the motor torque are in the same positive direction. In the regenerative region up to t2, the motor performs regenerative power generation, and regenerative power corresponding to the sum of the motor rotation speed and torque is generated and charged to the battery.
[0007]
On the other hand, in an electric vehicle, in order to prevent overcharging that causes deterioration of the battery, there is a restriction on charging of the battery. When regenerative power is generated, the regenerative power is limited when the battery is in the vicinity of full charge. Further, regenerative power generation is not performed on a fully charged battery.
For this reason, in a vehicle state where regenerative power is limited such as near full charge or full charge, the generation of regenerative torque of the motor is small or zero.
[0008]
[Problems to be solved by the invention]
As a result, when starting a fully charged electric vehicle on a hill, if the vehicle is rolled back or rolled forward, the vehicle will continue to descend in the downhill direction even if the accelerator is depressed, and the driver will eventually operate the foot brake. There is a problem that a great sense of incongruity occurs when the accelerator is stepped on.
An object of the present invention is to provide a regenerative power control device that can smoothly start a vehicle on an uphill road even in a fully charged state, and can start the vehicle without feeling uncomfortable. It is said.
[0009]
[Means for Solving the Problems]
Therefore, according to the first aspect of the present invention, in an electric vehicle including a drive motor and a battery, when the battery voltage exceeds a predetermined regeneration limit start voltage, or the charge depth of the battery exceeds a predetermined regeneration limit start charge depth. If the battery voltage or charging depth increases, the regenerative power is reduced, and the motor is regeneratively generated with a control pattern at the time of traveling to zero at a predetermined charging stop voltage or charging stop charging depth to charge the battery. Control means that can be operated, vehicle state detection means for detecting that the electric vehicle is in a rollback or rollforward state, and when the electric vehicle is in a rollback or rollforward state, Second control for generating a large amount of regenerative power on the fully charged side of the battery with respect to the control pattern It was assumed to have a regenerative power setting means for setting a turn.
[0010]
According to a second aspect of the present invention, the second control pattern generates the regenerative power in a region where the battery is overcharged.
[0011]
According to a third aspect of the present invention, the vehicle state detection means includes a vehicle speed detection sensor, judges a traveling direction of the electric vehicle based on a detection value of the vehicle speed sensor, and the electric vehicle rolls according to an operation position of a shift lever. It was assumed that a back or roll forward state was detected.
[0012]
According to a fourth aspect of the present invention, the regenerative power setting means sets the regenerative restriction start voltage or the regenerative restriction start charge depth higher than the control pattern during the travel as the second control pattern. It was supposed to be set.
[0013]
According to a fifth aspect of the invention, the regenerative power setting means sets, as the second control pattern, a charge stop voltage or a charge stop charge depth at which regenerative power generation is stopped higher than the control pattern during travel. did.
[0014]
According to a sixth aspect of the present invention, the control means feeds back to the regenerative power setting means information that the terminal voltage of the battery has become a regenerative restriction start voltage or a charge stop voltage, and the regenerative power setting means As the second control pattern, the regenerative power is set with a predetermined set value, and the set value is gradually reduced by a predetermined width every time information to be fed back is received.
[0015]
【The invention's effect】
According to the first aspect of the present invention, when the electric vehicle is in a rollback or rollforward state, the regenerative power setting means generates a large amount of regenerative power on the fully charged side of the battery with respect to the control pattern during travel. Set the control pattern. Thereby, the control means can generate more regenerative electric power, can generate or maintain the driving force generated, and the vehicle can start directly from the rollback or rollforward state. . As a result, it is possible to avoid the operation of stepping on the foot brake immediately after stepping on the accelerator, and the vehicle can be started with an operation without a sense of incongruity.
[0016]
In the invention according to claim 2, since regenerative power can be generated even in a region where the battery is overcharged, the effect of the invention of claim 1 is not limited to a region where regenerative power is limited, but also regenerative power generation such as full charge. Can be obtained even in the region where the operation is stopped.
Less frequent start up the vehicle in a fully charged state and short generation time of regenerative power, resulting in less damage to the battery, simpler configuration than providing separate discharge resistors, and no increase in cost An effect is obtained.
[0017]
In the invention according to claim 3, since it is determined whether the electric vehicle is in the rollback or rollforward state based on the traveling direction of the electric vehicle determined by the detection value of the vehicle speed sensor and the operation position of the shift lever, It is only necessary to use a certain signal, and there is an effect that does not accompany an increase in cost, such as providing another device.
[0018]
In the invention according to claim 4, since the second control pattern is configured such that the regeneration limit start voltage or the regeneration limit start charge depth for limiting the generation of regenerative power is set higher than the control pattern during traveling, the determination value It is possible to increase the regenerative power generated and to generate a large amount of regenerative torque simply by correcting the above. As a result, the vehicle can start from the rollback or rollforward state even when the regenerative power enters the restricted region.
[0019]
In the invention according to claim 5, since the second control pattern is configured to be configured such that the charge stop voltage or the charge stop charge depth for stopping the regenerative power generation is set higher than the control pattern during travel, The regenerative power can be raised only by correcting the determination value, and the regenerative power can be generated even in the region where the regenerative power generation is stopped. As a result, a fully charged vehicle can be started directly from the rollback or rollforward state.
[0020]
In the invention according to claim 6, the control means controls the restriction or stop of the regenerative power based on the terminal voltage of the battery. When it is determined that the terminal voltage of the battery has reached a voltage at which regenerative power generation is stopped, the information is fed back to the regenerative power setting means. In the regenerative power setting means, the regenerative power is set with a predetermined set value, and the set value is decreased by a predetermined width each time information to be fed back is received thereafter. As a result, whenever the regenerative power is limited or stopped, the voltage drop in the battery decreases, and the regenerative power is generated according to the control pattern at the time of travel until the open circuit voltage of the battery reaches the voltage that determines the regenerative power generation limit or stop Continued. The effect that the judgment value used for the control pattern at the time of traveling can be used as it is is obtained.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described by way of examples.
FIG. 1 is a block diagram showing the configuration of the embodiment.
A motor 2 and a battery 3 for driving the electric vehicle are connected to the control unit 1. A shift lever position detector 4 and an accelerator pedal stroke detector 5 are connected to the controller 1. A shift lever position detector 4 and a vehicle speed sensor 7 are connected to the vehicle state detector 6. The regenerative power setting unit 8 is connected to the vehicle state detection unit 6 and the control unit 1.
[0022]
The control unit 1 can shift-control the motor 2 in the positive and negative directions. When driving the motor 2, the motor driving speed is set according to the detection value of the shift lever position detection unit 4, and the acceleration is determined according to the detection value of the accelerator depression amount detection unit 5. When the shift lever is in the reverse position in the shift lever position detection unit 4, the motor is driven reversely to reverse the vehicle. As the motor control pattern, for example, the control pattern shown in FIG. 8 is used.
[0023]
The control unit 1 is provided with a voltage sensor for detecting the battery voltage. When the battery voltage is equal to or lower than a predetermined voltage, the torque determined by the motor control pattern is used as it is for motor control. If the voltage exceeds the predetermined voltage, the motor torque is reduced to limit the regenerative power.
[0024]
FIG. 2 shows a control pattern during traveling that limits the regenerative power. Up to the set regenerative restriction start voltage, regenerative power corresponding to the motor torque determined by the shift lever position and the accelerator pedal stroke is generated according to the motor control pattern. With this as a set upper limit value, the regenerative power is limited to zero as the battery voltage rises between the regeneration limit start voltage and the charge stop voltage.
[0025]
When it is detected from the vehicle state detection unit 6 that the vehicle is in the rollback or rollforward state, as shown by the dotted line, the charge stop voltage is set to a large value again as the second control pattern, and the regeneration limit start voltage is During the charging stop voltage, the regenerative power is limited to zero as the battery voltage increases. As a result, the regenerative electric power after the start of the regenerative restriction is lifted from the control pattern at the time of traveling, and a large motor torque can be generated.
[0026]
The vehicle state detection unit 6 detects that the vehicle is in a rollback or rollforward state. For this purpose, first, based on the detection value of the vehicle speed sensor 7, it is determined whether the vehicle moves forward or back. The determination result is compared with the shift lever position detected by the shift lever position detection unit, and it is detected that the vehicle is in a rollback or rollforward state.
[0027]
That is, when the shift lever position is “D”, “1st”, “2nd”, all indicate the intention of moving the vehicle forward. At this time, if the vehicle moves in the opposite direction, the vehicle is in the rollback state. It will be.
Further, when the shift lever position is “R”, it indicates an intention of moving the vehicle backward. At this time, when the vehicle moves in the forward direction, the vehicle is in a roll forward state.
[0028]
First, the control unit 1 selects a control pattern to be applied depending on whether the vehicle state detection unit 6 detects that the vehicle has entered the rollback or rollforward state. In the normal traveling state, the regenerative power is limited using a control pattern during traveling.
[0029]
When rollback or rollforward is detected, the regenerative torque becomes insufficient when the regenerative power is limited, so the control unit 1 selects the second control pattern that generates more regenerative power, and the motor 2 To control. As a result, the motor torque generated in the vehicle increases, and the vehicle can start from a rollback or rollforward state. Operation such as having to step on the brake after stepping on the accelerator becomes unnecessary.
Here, the battery may be temporarily overcharged, but the slope start at full charge is infrequent and the time is short, so it hardly affects the deterioration of the battery.
[0030]
Next, a modification of the embodiment will be described.
In the above embodiment, the control pattern for determining the limit of the regenerative power is used by the terminal voltage of the battery. However, for example, the depth of charge (SOC) is detected, and the limit of the regenerative power is determined by the charge depth. The motor 2 can also be controlled.
[0031]
FIG. 3 is a diagram illustrating a control pattern used for limiting the regenerative power based on the charging depth.
The control pattern during traveling is indicated by a solid line, and regenerative electric power corresponding to the motor torque determined by the shift lever position and the amount of accelerator depression is generated as a set upper limit value until the set regenerative restriction start charging depth. Between the charge depth at which the regeneration limit start and the charge stop are determined, the generation of regenerative power is limited to zero as the charge depth increases.
[0032]
The second control pattern applied to the rollback or rollforward state is indicated by a dotted line, and the charging depth for determining whether to restrict regeneration or stop charging is set to be larger than the control pattern during traveling. As a result, when the regenerative power is limited by the control pattern at the time of traveling, it is possible to generate a larger regenerative power by switching the control pattern, and the motor torque becomes large, so that the vehicle can be You can start directly from the rollback or rollforward state.
[0033]
Next, a second modification will be described.
In this modification, when the control unit 1 detects that the terminal voltage of the battery 3 has become the regenerative restriction start voltage or the charge stop voltage, the information is fed back to the regenerative power setting unit 8. As the second control pattern, the regenerative power setting unit 8 sets the regenerative power with a set value smaller than the set upper limit value, and thereafter decreases the set value stepwise within a predetermined range each time information is fed back from the control unit 1. .
[0034]
FIG. 4 is a diagram illustrating changes in battery terminal voltage and regenerative power during control. In the figure, the case where the terminal voltage becomes the regeneration limit start voltage is shown as an example, and when the terminal voltage becomes the charge stop voltage, the regeneration limit start voltage may be replaced with the charge stop voltage.
When the battery 2 is charged with the set upper limit value and the terminal voltage of the battery reaches the regeneration limit start voltage at t0, the regenerative power setting unit 8 sets the regenerative power with a set value smaller than the set upper limit value. As a result, the terminal voltage of the battery decreases, and regenerative power is generated at the set value until the terminal voltage reaches the regeneration limit start voltage again.
[0035]
When the terminal voltage becomes the regeneration limit start voltage again, the set value is decreased by a predetermined width to limit the generation of regenerative power. By reducing the regenerative power stepwise in this way, the regenerative power limit is started not after the terminal voltage of the battery but the open circuit voltage becomes the regenerative limit start voltage. Since the reduction range of the set value here can be set smaller than the limit after the start of the regenerative restriction, the regenerative power can be generated larger than the restriction in the restricted region. Motor torque also increases.
[0036]
In addition, even when the regenerative limiting voltage is replaced with the charge stop voltage, regenerative power can be continuously generated until the open circuit voltage of the battery becomes the charge stop voltage after the charge is stopped at the terminal voltage.
Thereby, large regenerative electric power can be generated without resetting the determination value determined by the control pattern during traveling.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an embodiment.
FIG. 2 is a diagram illustrating a control pattern and a second control pattern during traveling.
FIG. 3 is a diagram showing a control pattern in a modified example.
FIG. 4 is a diagram showing a control pattern in a modified example.
FIG. 5 is a diagram showing changes in acceleration, speed, and displacement when starting on a slope.
FIG. 6 is an explanatory diagram when the brake is released.
FIG. 7 is an explanatory diagram when the accelerator pedal is depressed.
FIG. 8 is a diagram showing a torque curve.
[Explanation of symbols]
1 Control unit (control means)
2 Motor 3 Battery 4 Shift lever position detector 5 Accelerator step amount detector 6 Vehicle state detector (vehicle state detector)
7 Vehicle speed sensor (vehicle speed detection sensor)

Claims (6)

In an electric vehicle equipped with a drive motor and a battery,
When the battery voltage exceeds the specified regenerative limit start voltage or the battery charge depth exceeds the specified regenerative limit start charge depth, the regenerative power is reduced as the battery voltage or charge depth increases, and the predetermined charge Control means capable of charging the battery by regeneratively generating the motor with a control pattern at the time of running with zero at stop voltage or charge stop charge depth ,
Vehicle state detection means for detecting that the electric vehicle is in a rollback or rollforward state;
If the electric car has become rolled back or roll forward state, the control pattern during the traveling, the regenerative power setting means for setting a second control pattern that generates much regenerative power in the fully charged side of the battery A regenerative power control apparatus comprising: The regenerative power control apparatus according to claim 1, wherein the second control pattern generates the regenerative power in a region where the battery is overcharged. The vehicle state detection means includes a vehicle speed detection sensor, determines a traveling direction of the electric vehicle based on a detection value of the vehicle speed sensor, and the electric vehicle enters a rollback or rollforward state depending on an operation position of a shift lever. The regenerative power control apparatus according to claim 1, wherein The regenerative power setting means sets, as the second control pattern, a regenerative restriction start voltage or a regenerative restriction start charge depth that restricts the generation of regenerative power higher than the control pattern during travel. The regenerative power control apparatus according to claim 1 or 2. The regenerative power setting means sets, as the second control pattern, a charge stop voltage for stopping regenerative power generation or a charge stop charge depth higher than the control pattern during travel. The regenerative power control apparatus according to 2 or 4. The control means feeds back to the regenerative power setting means information that the terminal voltage of the battery has become a regenerative restriction start voltage or a charge stop voltage, and the regenerative power setting means, as the second control pattern, The regenerative power control apparatus according to claim 1, wherein the regenerative power is set with a predetermined set value, and the set value is decreased stepwise by a predetermined width every time information to be fed back is received.

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