JP2000270404A - Regenerative power control device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To enable an electric vehicle to be started directly from a rollback or rollforward state. A regenerative electric power corresponding to a motor torque determined by a shift lever and an accelerator depression amount is generated as a set upper limit value until a battery voltage becomes a regeneration limit start voltage. The regenerative power is limited as the battery voltage rises between the regenerative limit start voltage and the charge stop voltage indicated by the solid line. When the vehicle state is rolled back or rolled forward, the charging stop voltage is set high as shown by the dotted line. As a result, a larger regenerative power can be generated in the regenerative power limit region than before.
The vehicle can be launched directly from a rollback or rollforward state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration of a regenerative power control device for charging a battery with kinetic energy in an electric vehicle, and more particularly, to a device capable of performing a comfortable operation for a driver when starting on a slope.

[0002]

2. Description of the Related Art When a vehicle is started on an uphill, if the component of gravity in the downhill direction is greater than the driving force (creep) between the time the brake is released and the time the accelerator is depressed, acceleration occurs in the downhill direction. The vehicle moves backward. This phenomenon is called rollback. In addition, when the vehicle is going backward on a downhill, the forward movement in the downhill direction is called roll forward. In both cases, the vehicle moves in the direction opposite to the desired direction.

FIG. 5 is a diagram showing acceleration, speed, and displacement when an electric vehicle is started on a slope. Where 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 only forces acting on the vehicle are the creep force F generated by the motor and the gravity Mg as shown in FIG. When the component force Mgsinθ of the gravity Mg in the slope direction is larger 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 direction of descending slope as shown in FIG.

When the accelerator pedal is depressed at time t1, the driving force generated by the motor increases, and as shown in FIG. 7, the driving force F becomes larger than the gradient direction component Mgsin θ of gravity Mg.
As shown in FIG. 5A, the resultant force turns in the positive direction. The vehicle speed starts to decrease as shown in FIG. The vehicle keeps moving backward as shown in FIG. When the vehicle speed becomes zero at t2 due to the deceleration, the vehicle turns in the forward direction and starts climbing the slope while increasing the speed.

When the vehicle speed is in the negative direction and 0 <t ≦ t2,
Since the driving force of the motor is in the positive direction as shown by the dotted line in (a), regenerative electric power is generated by the power generation principle of the motor, and the battery is charged. A region where the vehicle speed is negative with respect to the positive driving force is a so-called rollback region. This will be described below with reference to a torque curve diagram for controlling the electric vehicle.

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 rotation speed increases in the reverse direction while generating creep force on the motor. When the accelerator is depressed at time t = t1, the motor torque increases in accordance with a predetermined control pattern, and when the acceleration becomes larger than the component of gravity on the slope, the vehicle stops retreating and the vehicle speed changes in the forward direction. After the time t = t2, the vehicle speed and the motor torque have the same positive direction. In the regenerative region up to t2, the motor generates regenerative electric power, generates regenerative electric power corresponding to the sum of the motor speed and torque, and charges the battery.

[0007] On the other hand, in an electric vehicle, a limit is imposed on charging of the battery in order to prevent overcharging which causes deterioration of the battery. When regenerative electric power is generated, the regenerative electric power is limited when the battery is in the vicinity of full charge. Also, regenerative power generation is not performed for a fully charged battery. For this reason, in a vehicle state in which regenerative power is limited, such as near full charge or full charge of the battery, generation of regenerative torque of the motor is small or zero.

[0008]

As a result, when a fully charged electric vehicle is started on a sloping road, if the vehicle is in a rollback or rollforward state, even if the accelerator is depressed,
As the vehicle continues to descend in the downhill direction, the driver finally operates the foot brake to stop the vehicle, and there is a problem that a great discomfort occurs when the accelerator pedal is depressed. An object of the present invention is to provide a regenerative power control device capable of smoothly starting a vehicle on an ascending road even when the vehicle is fully charged and starting the vehicle without feeling uncomfortable in view of the above problems. And

[0009]

According to a first aspect of the present invention, there is provided an electric vehicle including a driving motor and a battery, wherein the motor is regenerated by a predetermined control pattern to charge the battery. Possible control means, and vehicle state detection means for detecting that the electric vehicle has entered a rollback or rollforward state,
Regenerative power setting means for setting a second control pattern that generates a large amount of regenerative power on the fully charged side of the battery with respect to a control pattern when the electric vehicle is in a rollback or rollforward state. It had it.

According to a second aspect of the present invention, the second control pattern generates the regenerative power in an area where the battery is overcharged.

According to a third aspect of the present invention, the vehicle state detecting means includes a vehicle speed detecting sensor, which determines a traveling direction of the electric vehicle based on a detection value of the vehicle speed sensor, and determines the driving direction of the electric vehicle based on an operation position of a shift lever. It is intended to detect that the vehicle has entered a rollback or rollforward state.

According to a fourth aspect of the present invention, the regenerative power setting means sets a regenerative limit start voltage or a regenerative limit start charging for limiting generation of regenerative power as the second control pattern more than the control pattern during traveling. The depth was set higher.

According to a fifth aspect of the present invention, the regenerative power setting means sets, as the second control pattern, a charging stop voltage for stopping regenerative power generation or a charging stop charging depth higher than the control pattern during traveling. To do.

According to a sixth aspect of the present invention, the control means feeds back information to the regenerative power setting means that the terminal voltage of the battery has reached the regenerative limit start voltage or the charging stop voltage, and the regenerative power setting means The regenerative power is set at a predetermined set value as the second control pattern, and the set value is reduced stepwise by a predetermined width every time information to be fed back is received.

[0015]

According to the first aspect of the present invention, when the electric vehicle enters the rollback or rollforward state, the regenerative power setting means sets the regenerative power on the fully charged side of the battery with respect to the control pattern during traveling. A second control pattern that frequently occurs is set. This allows the control means to generate more regenerative power, generate or maintain the generated driving force, and allow the vehicle to start directly from the rollback or rollforward state . As a result, the operation of stepping on the foot brake immediately after stepping on the accelerator can be avoided, and the vehicle can be started with an operation that does not cause discomfort.

According to the second aspect of the present invention, regenerative power can be generated even in an area where the battery is overcharged.
The effect of the first aspect of the present invention can be obtained not only in a region where the regenerative power is limited, but also in a region where regenerative power generation is stopped such as full charge. Since the vehicle starts on an uphill road less frequently when fully charged and the regenerative power generation time is short, the damage to the battery is small, the configuration is simpler than providing a separate discharge resistor, and the cost does not increase. The effect is obtained.

According to the third aspect of the present invention, it is determined whether the electric vehicle has entered the rollback or rollforward state based on the traveling direction of the electric vehicle and the operating position of the shift lever determined by the detection value of the vehicle speed sensor. In addition, it is only necessary to use a signal present in the vehicle, and there is an effect that the cost is not increased by providing other devices.

According to the fourth aspect of the present invention, the second control pattern is configured such that the regenerative limit start voltage or the regenerative limit start charging depth for limiting generation of regenerative electric power is set higher than the control pattern during traveling. By simply correcting the determination value, the generated regenerative electric power can be increased and a large amount of regenerative torque can be generated. Thus, even if the regenerative electric power enters the restricted area, the vehicle can be started from the rollback or rollforward state.

According to the fifth aspect of the present invention, the second control pattern is configured such that the charging stop voltage for stopping regenerative power generation or the charging stop charging depth is set higher than the control pattern during traveling. Similarly to the above, the regenerative electric power can be raised only by correcting the determination value, and the regenerative electric power can be generated even in a region where regenerative power generation is stopped. Thus, a fully charged vehicle can be started directly from the rollback or rollforward state.

According to the present invention, the control means controls the limitation 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 the voltage at which the regenerative power generation is stopped, the information is fed back to the regenerative power setting means. The regenerative power setting means sets the regenerative power at a predetermined set value, and thereafter decreases the set value by a predetermined width every time information to be fed back is received. As a result, every time the regenerative power is limited or stopped, the voltage drop in the battery is reduced, and the regenerative power is generated according to the control pattern during traveling until the open-circuit voltage of the battery reaches a voltage for determining the limit or stop of the regenerative power generation. Continued. The effect is obtained that the determination value used for the control pattern during traveling can be used as it is.

[0021]

Next, embodiments of the present invention will be described with reference to examples. FIG. 1 is a block diagram showing the configuration of the embodiment. Motor 2 and battery 3 for driving electric vehicle
Are connected to the control unit 1. The control unit 1 is connected with a shift lever position detection unit 4 and an accelerator depression amount detection unit 5. The shift lever position detecting section 4 and the vehicle speed sensor 7 are connected to the vehicle state detecting section 6. The vehicle state detection unit 6 and the control unit 1 are connected to the regenerative power setting unit 8.

The control unit 1 can control the speed of the motor 2 in the positive and negative directions. When driving the motor 2, the driving speed of the motor 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 by the shift lever position detector 4, the motor is driven in reverse to back the vehicle. For example, a control pattern shown in FIG. 8 is used as the motor control pattern.

The control unit 1 is provided with a voltage sensor for detecting a battery voltage.
The torque determined by the motor control pattern is directly used for motor control. When the voltage exceeds the predetermined voltage, the motor torque is reduced to limit the regenerative electric power.

FIG. 2 shows a control pattern during running in which the regenerative electric power is limited. Up to the set regenerative limit start voltage, regenerative electric power corresponding to the motor torque determined by the shift lever position and the accelerator pedal depression amount is generated in accordance with the motor control pattern. With this as the set upper limit, between the regenerative limit start voltage and the charge stop voltage, the regenerative power is limited to zero as the battery voltage increases.

When the vehicle state detecting section 6 detects that the vehicle has entered the rollback or rollforward state, as shown by the dotted line in the second control pattern, the charging stop voltage is reset to a large value, and the regeneration limit is set. During the period from the start voltage to the charge stop voltage, the regenerative power is limited to zero as the battery voltage increases. As a result, the regenerative power after the start of the regenerative restriction is raised more than the control pattern at the time of traveling, and a large motor torque can be generated.

The vehicle state detector 6 detects that the vehicle has entered the rollback or rollforward state. For this purpose, first, it is determined whether the vehicle moves forward or backwards based on the detection value of the vehicle speed sensor 7. The result of the determination is compared with the shift lever position detected by the shift lever position detection unit to detect that the vehicle has entered the rollback or rollforward state.

That is, the shift lever position is "D",
Both "1st" and "2nd" indicate an intention to move the vehicle forward, and moving the vehicle in the opposite direction at this time means that the vehicle is in a rollback state. When the shift lever position is "R", it indicates an intention to move the vehicle backward. At this time, moving the vehicle in the forward direction means that the vehicle is in the roll forward state.

The control unit 1 first selects a control pattern to be applied depending on whether a rollback or a rollforward state has been detected based on the detection result of the vehicle state detection unit 6. In a normal traveling state, the regenerative power is limited using a control pattern during traveling.

When the rollback or rollforward is detected, if the regenerative power is limited, the regenerative torque becomes insufficient. Therefore, the control unit 1 selects the second control pattern that generates more regenerative power. , And controls the motor 2. As a result, the motor torque generated in the vehicle increases, and the vehicle can start from the rollback or rollforward state. There is no need to operate the brakes after stepping on the accelerator. Here, the battery may be temporarily overcharged, but the start of the sloping road at the time of full charge is less frequent and the time is short, so that the deterioration of the battery is hardly affected.

Next, a modification of the embodiment will be described.
In the above embodiment, the control pattern for determining the limit of the regenerative power based on the terminal voltage of the battery is used. In addition, for example, the state of charge (SOC) is detected, and the limit of the regenerative power is determined based on the state of charge. , The motor 2 can also be controlled.

FIG. 3 is a diagram showing a control pattern used to limit the regenerative power at the charging depth. The control pattern at the time of running is indicated by a solid line, and regenerative power corresponding to the motor torque determined by the shift lever position and the amount of depression of the accelerator is generated as a set upper limit value up to the set regenerative limit start charging depth. Between the start of regenerative restriction and the charge depth at which charging is determined to stop, the generation of regenerative electric power is limited to zero as the charge depth increases.

The second control pattern applied to the rollback or rollforward state is indicated by a dotted line, and the depth of charge for judging the start of regeneration and the stop of 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 during traveling, a larger regenerative power can be generated by switching the control pattern, and the motor torque is increased. It can be launched directly from the rollback or rollforward state.

Next, a second modification will be described. In this modified example, when the control unit 1 detects that the terminal voltage of the battery 3 has reached the regenerative limit start voltage or the charge stop voltage, the information is fed back to the regenerative power setting unit 8. The regenerative power setting unit 8 sets the regenerative power with a set value smaller than the set upper limit value as a second control pattern, and thereafter gradually reduces the set value by a predetermined width every time information is fed back from the control unit 1. .

FIG. 4 is a diagram showing changes in battery terminal voltage and regenerative power during control. Note that, in the figure, the case where the terminal voltage becomes the regeneration limit start voltage is shown as an example,
When the charge stop voltage is reached, the regeneration limit start voltage may be replaced with the charge stop voltage. When the battery 2 is charged at the set upper limit value and the terminal voltage of the battery reaches the regeneration start voltage at t0, the regenerative power setting unit 8 sets the regenerative power at 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 again reaches the regeneration limit start voltage.

When the terminal voltage again reaches the regeneration start voltage, the set value is reduced by a predetermined width to limit the generation of regenerative power. By gradually reducing the regenerative power in this way, the start of the limit of the regenerative power is not the terminal voltage of the battery,
This is performed after the open circuit voltage reaches the regeneration limit start voltage. Since the amount of decrease in the set value here can be set smaller than the limit after the start of the regenerative restriction, the regenerative power can be generated more than when the regenerative power is restricted in the restricted area. The motor torque also increases.

Further, even when the regeneration limit voltage is replaced with the charging stop voltage, and even after the charging is stopped at the terminal voltage, the regenerative power can be continuously generated until the open voltage of the battery becomes the charging stop voltage. As a result, large regenerative 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 showing a control pattern during traveling and a second control pattern.

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 a 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]

 DESCRIPTION OF SYMBOLS 1 Control part (control means) 2 Motor 3 Battery 4 Shift lever position detecting part 5 Accelerator stepping amount detecting part 6 Vehicle state detecting part (vehicle state detecting means) 7 Vehicle speed sensor (vehicle speed detecting sensor)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H115 PA01 PA08 PA11 PC06 PG04 PI16 PI29 PU01 QE04 QE06 QE10 QE13 QH05 QH06 QH08 QI04 SE06 TB01 TI02 TI05 TO01 TO21 TO30 TU16

Claims (6)

[Claims] 1. An electric vehicle comprising a driving motor and a battery, a control means capable of charging the battery by regenerating the motor in a predetermined control pattern, wherein the electric vehicle is rolled back or rolled. Vehicle state detecting means for detecting the forward state; and when the electric vehicle is in the rollback or rollforward state, the regenerative electric power on the fully charged side of the battery is increased with respect to the control pattern during traveling. A regenerative power setting device for setting a generated second control pattern. 2. The regenerative power control device according to claim 1, wherein the second control pattern is for generating the regenerative power in a region where the battery is overcharged. 3. The vehicle state detection means includes a vehicle speed detection sensor, and determines a traveling direction of the electric vehicle based on a detection value of the vehicle speed sensor. 2. The regenerative power control device according to claim 1, wherein the regenerative power control device detects that a roll-forward state has occurred. 4. The regenerative electric power setting means, as the second control pattern,
The regenerative power control device according to claim 1 or 2, wherein a regenerative limit start voltage or a regenerative limit start charging depth for limiting generation of regenerative power is set high. 5. The regenerative power setting means, as the second control pattern, is more controlled than the control pattern during traveling.
5. The regenerative power control device according to claim 1, wherein a charge stop voltage for stopping regenerative power generation or a charge stop charge depth is set high. 6. The control means feeds back information to the regenerative power setting means that the terminal voltage of the battery has become a regenerative limit start voltage or a charge stop voltage, and the regenerative power setting means is configured to output the second power from the second terminal. The regenerative power control according to claim 1, wherein the regenerative power is set at a predetermined set value as the control pattern, and the set value is reduced stepwise by a predetermined width every time information to be fed back is received. apparatus.