KR102224165B1 - A motor torque control method for improving braking linearity of hybrid vehicles - Google Patents

Abstract

In the present invention, when the driver presses the brake pedal (On), the brake controller 1 calculates and distributes the braking amount A according to the brake depth (depth) (S1), and the vehicle speed is signaled from the vehicle speed sensor. Comparing the preset speed value (E) from (S2), when the vehicle speed is greater than the preset speed value, the allowable amount of regenerative braking is calculated by the brake controller (1) and provided to the vehicle controller (2). Step (S3), in the vehicle controller (2), receiving the allowable amount of regenerative braking from the brake controller (1) and transmitting the regenerative braking command (C) to the motor controller (3) (S4), regenerative braking according to the regenerative braking command Calculating the amount of execution (D) (S5), the friction of the brake controller subtracting the amount of regenerative braking (D) calculated in the step (S5) from the amount of braking (A) calculated in the step (S1) Including the step (S6) of transmitting the braking command to the hydraulic pump under the control of the brake controller, and the step (S7) of applying the friction braking by the hydraulic pressure by the hydraulic pump according to the command in the step (S6). As a result, the brake controller, vehicle controller, and motor controller are braking by regenerative braking force, hydraulic pressure, and motor braking forces under cooperative control of the braking amount according to the brake depth, and the cost regenerative torque at the time of stepping on the brake even when the vehicle speed decreases. When the brake depth is the same by maintaining a constant value, a constant deceleration linearity can be secured.

Description

A MOTOR TORQUE CONTROL METHOD FOR IMPROVING BRAKING LINEARITY OF HYBRID VEHICLES}

The present invention relates to a motor torque control method for improving braking linearity of a hybrid vehicle.In particular, the braking linearity is improved by controlling a coast regeneration torque in cooperative control of friction braking by a brake and regenerative braking by a motor. And it relates to a motor torque control method for increasing the amount of regenerative braking.

Hybrid vehicle refers to driving a vehicle by efficiently combining two or more different types of power sources, but in most cases, it is used in engines that obtain rotational power by burning fuel (fossil fuels such as gasoline) and electric motors that obtain rotational power by battery power. It refers to a vehicle driven by a vehicle, and this is commonly referred to as a hybrid electric vehicle (HEV).

These hybrid vehicles are future vehicles that can improve fuel efficiency and reduce exhaust gas by adopting electric motors as well as engines as auxiliary power sources, and more actively research in response to the demands of the times to improve fuel economy and develop eco-friendly products. Has become.

Hybrid vehicles are EV (Electric Vehicle) mode, which is a pure electric vehicle mode that uses only the power of an electric motor (driving motor), and HEV (Hybrid Electric Vehicle) mode that uses the rotational power of the driving motor as the auxiliary power while the rotational power of the engine is used as the main power, The vehicle is driven in a driving mode, such as a regenerative braking (RB) mode, in which braking and inertial energy is recovered through power generation of the drive motor and charged to a battery when the vehicle is braking or traveling on other roads.

Electric vehicles use part of the braking force for power generation when braking, and use the generated electric energy to charge the battery.By using part of the kinetic energy by the driving speed of the vehicle as energy required to drive the generator. , Reduction of kinetic energy (that is, reduction of driving speed) and generation of electric energy are simultaneously implemented. This type of braking method is called regenerative braking.

The generation of electric energy during the regenerative braking may be achieved by driving a separate generator or the motor in reverse. When braking the electric vehicle, the mileage of the electric vehicle can be improved by regenerative braking control. In the case of a hybrid electric vehicle, the fuel economy can be improved and the emission of harmful exhaust gas can be reduced.

In this way, the mechanical energy of the engine and the electric energy of the battery are used together, the optimum operating range of the engine and the driving motor is used, and energy is recovered by the driving motor during braking, so that vehicle fuel efficiency and efficient energy use are possible.

In general, braking is performed by cooperative control between a brake and a motor during braking in a hybrid vehicle. The driver's braking demand is determined by the brake depth, which is satisfied by the friction braking and regenerative braking of the hydraulic braking system. In the case of motor torque, the final torque is determined by adding the regenerative braking torque and the cost regenerative torque, so the braking force increases or decreases as much as the cost regenerative torque during braking.

However, due to this, even if the driver steps on the brake at the same depth and requests the same braking force, the braking force changes as the vehicle speed decreases, resulting in a feeling of heterogeneity.Moreover, in recent years, in the trend of increasing the cost regenerative torque, the above-described same brake depth On the other hand, the sense of heterogeneity during braking due to the different braking force according to the vehicle speed is increasing.

Japanese Patent Laid-Open No. 2006-96218 discloses a brake control device that performs regenerative cooperative control by adjusting the hydraulic pressure supplied to the hydraulic brake during regenerative braking by the hydraulic control device.

However, in a conventional hybrid vehicle, the cost regenerative torque decreases as the vehicle speed decreases, so even if the brake is applied equally, the deceleration rate is not constant and changes as shown in the deceleration graph schematically shown in FIG. At the same time, a different braking force is applied to each braking operation, resulting in a feeling of disparity, resulting in a problem of safe driving due to confusion of the driver, and a decrease in driving convenience and product quality.

Japanese Patent Publication No. 2006-96218

The present invention solves the above-described problems of the prior art, and controls the cost regenerative torque during cooperative control of frictional braking by a brake during braking of a vehicle and regenerative braking by a motor, thereby improving a sense of heterogeneity during braking with improved braking linearity. It is to provide a motor torque control method for improving braking linearity during regenerative braking of a vehicle.

Another object of the present invention is to provide a motor torque control method for improving braking linearity during regenerative braking of a hybrid vehicle, which is improved to increase the energy recovery rate by increasing the amount of regenerative braking due to the cost regenerative maintained during braking.

In order to achieve the above object, the motor torque control method for improving braking linearity during regenerative braking of a hybrid vehicle according to the present invention is, when the driver presses the brake pedal (On), according to the brake depth (depth) in the brake controller. Calculating and distributing the braking amount (A) (S1),

Comparing the speed of the vehicle from the signal of the vehicle speed sensor to a preset speed value (E) (S2),

If the vehicle speed is greater than a preset speed value, calculating the allowable amount of regenerative braking in the brake controller and providing it to the vehicle controller (S3),

In the vehicle controller, receiving the allowable regenerative braking amount from the brake controller and transmitting the regenerative braking command (C) to the motor controller (S4),

Calculating a regenerative braking execution amount (D) according to the regenerative braking command (S5),

The brake controller transmits a friction braking command of the value obtained by subtracting the regenerative braking execution amount (D) calculated in the step (S5) from the braking amount (A) calculated in the step (S1) to the hydraulic pump under the control of the brake controller. Step (S6),

It comprises a step (S7) of applying the friction braking by hydraulic pressure by the hydraulic pump in accordance with the command in the step (S6).

Following the step (S7), comparing the vehicle speed by the speed signal from the vehicle speed sensor and a preset speed value (F) (S8), when the vehicle speed is greater than the set speed value (F) in the step (S8) Checking the on/off of the brake again (S9), when the brake is in the off state, transmitting the coast regenerative torque command corresponding to the current vehicle speed from the vehicle controller 2 to the motor controller 3 (S11) , And a step (S12) of allowing the motor torque to be applied by the motor controller 3 may be further included.

In addition, when the brake is turned off in step S9, a step S10 of setting the braking amount according to the brake depth to “0” in the brake controller may be further included.

In addition, when the brake is turned on in step S9, the process returns to step S1 to repeat steps S1 to S8.

In the case where the vehicle speed is less than the set speed value F in step S8, it further comprises a step S21 of setting the allowable regenerative braking amount to “0”, and the allowable regenerative braking amount is set at “0” in step S21. Setting to is to perform the braking amount according to the brake depth calculated by the brake controller in step S1 by hydraulic pressure.

In the step S21, the brake controller transmits the setting of the allowable regenerative braking amount to "0" to the vehicle controller prior to the step S4.

In addition, as the allowable amount of regenerative braking is set to "0" in the step S21, the brake controller transmits the Coast Regen torque compensation friction braking command B to the hydraulic pump under the control of the brake controller.

When the driver presses the brake pedal (On), the vehicle controller may further include a step (S30) of transmitting a command (G) for maintaining the cost regenerative torque at the time of the brake on to the motor controller.

The cost regenerative torque maintenance command (G) in step S30 and the regenerative braking command (C) in step S4 are transmitted to the motor controller so that the motor torque (G+C) is applied.

According to the motor torque control method for improving braking linearity during regenerative braking of a hybrid vehicle of the present invention, the brake controller, the vehicle controller, and the motor controller control the braking amount according to the brake depth by regenerative braking force and hydraulic pressure and motor braking forces under cooperative control. By making braking, even if the vehicle speed decreases, the cost regenerative torque at the time the brake is applied is kept constant, so that if the brake depth is the same, a constant deceleration linearity can be secured, and at the end of the regenerative braking, the cost regenerative torque is reduced. It has the effect of maintaining the deceleration by increasing the frictional braking by the size.

1 is a graph showing that when braking of a conventional hybrid vehicle, a vehicle speed decreases and a cost regenerative torque decreases, so that the deceleration rate changes even if the brake is equally applied.
2 is a block diagram showing a schematic configuration of a control device for implementing a motor torque control method according to the present invention.
3 is a flowchart illustrating an operation of a motor torque control method according to the present invention.
4 is a graph of deceleration with improved linearity by the motor torque control method according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings showing embodiments of the present invention.

In FIG. 2, a control device for executing a motor torque control method for improving braking linearity during regenerative braking of a hybrid vehicle according to the present invention calculates a total braking amount and refers to the amount of regenerative braking performed by the vehicle controller. The brake controller (AHB) (1) that distributes the braking force of the brake and the regenerative braking command is determined in consideration of the regenerative prohibition situation, and the amount of regenerative braking is estimated in consideration of the state of the motor and transmission and transmitted to the brake controller. And a vehicle controller (HCU) 2 that enables the brake controller to distribute braking force, and a motor controller (MCU) 3 that performs regenerative braking in accordance with the regenerative braking command of the vehicle controller.

The motor controller 3 controls the inverter in response to the regenerative braking command of the vehicle controller 2 and transmits the motor output torque to the vehicle controller to the regenerative braking execution amount motor controller.

It may further include a shift controller 5 selectively depending on the vehicle, and provides shift state information of the transmission to the vehicle controller 2. The shift controller is not applied to a reduction gear type electric vehicle/fuel cell vehicle.

In hybrid vehicles, the cost regenerative torque is mapped to have different values depending on the vehicle speed and gear stage. In the prior art, the cost regenerative torque varies due to vehicle speed fluctuations due to deceleration and gear stage change, so even if the driver constantly presses the brake pedal to request the same braking force, the total amount of braking of the vehicle is not kept constant, resulting in a feeling of heterogeneity during braking. In order to solve the problem, in the present invention, the motor torque is controlled to maintain the cost regenerative torque at the time when the brake pedal is pressed, the cost regenerative torque is reduced at the end of regenerative braking, and the frictional braking is increased by the reduced cost regenerative torque. Keep the total braking amount constant.

Hereinafter, a motor torque control method for improving braking linearity during regenerative braking of a hybrid vehicle according to the present invention will be described in detail with reference to an operation flowchart of FIG. 3.

First, when the driver presses the brake pedal (On), the brake controller 1 calculates the braking amount A according to the brake depth (depth) and distributes it together with the distribution (step S1). The vehicle controller 2 transmits a command G to maintain the cost regenerative torque at the time of brake ON to the motor controller 3 (step S30).

Then, by comparing the speed value (E) set in advance from the signal of the vehicle speed sensor (step S2), for example, if it is greater than 10 km/h, the allowable amount of regenerative braking is calculated by the brake controller (1). It is provided to the vehicle controller 2 (step S3).

The vehicle controller 2 receives the allowable regenerative braking amount from the brake controller 1 and transmits the regenerative braking command (C) to the motor controller 3 (step S4), and the regenerative braking execution amount (D) according to the regenerative braking command Is calculated (step S5) and supplied to the brake controller 1.

At this time, the brake controller transmits a friction braking command of a value obtained by subtracting the regenerative braking execution amount D from the braking amount A calculated in step S1 to the hydraulic pump under the control of the brake controller (step S6), Friction braking is applied by hydraulic pressure by a hydraulic pump (step S7).

Then, the vehicle speed by the speed signal from the vehicle speed sensor is compared with the preset speed value (F), for example, 3 to 5 km/h (step S8), and if the vehicle speed is greater than the set speed value (F), the brake is performed again. Is checked (step S9), and if the brake is on, returns to the step (S1), and steps (S1 to S8) are repeatedly performed.

When the brake is off in step S9, the brake controller 1 sets the braking amount according to the brake depth to "0" (step S10), and the vehicle controller 2 responds to the current vehicle speed. The resulting cost regenerative torque command is transmitted to the motor controller 3 (step S11), and the motor torque is applied by the motor controller 3 (step S12).

If the vehicle speed value in the step S2 is less than the preset speed value E, the allowable regenerative braking amount is set to "0" (step S15), and the corresponding regenerative braking command is transmitted to the motor controller 3 Step S4 and the above-described subsequent steps are performed.

In the above step (S8), when the vehicle speed is less than the speed value (F), the vehicle controller 2 transmits a command for setting the cost regenerative torque to "0" to the motor controller 3 (step S20), and In the brake controller 1, the allowable amount of regenerative braking is set to "0" (step S21).

In this way, setting the allowable regenerative braking amount to "0" in the brake controller 1 means that braking by the motor is set to "0" and the braking by hydraulic pressure is set to "100", assuming the required braking amount is "100". Means to run into ".

This is because even if the vehicle speed is sufficiently decelerated to, for example, 3 to 5 km/h or less, if the cost regenerative torque is continuously applied, the vehicle may eventually retreat, i.e., retreat. At a sufficiently decelerated speed value set in advance, the cost regenerative torque and the allowable amount of regenerative braking in the vehicle controller 2 and the brake controller 1 are set to "0", respectively, and braking is performed only by hydraulic pressure.

In the step (S21), the brake controller (1) transmits the regenerative braking allowable amount set to "0" to the vehicle controller (2), and transmits the corresponding regenerative braking command to the motor controller (3) in the step (S4). Let it be. In addition, in the step (S21), the brake controller transmits the coast regenerative torque compensation friction braking command (B) to the hydraulic pump under the control of the brake controller as the allowable regenerative braking amount is set to "0". Allows friction braking to be performed by the controller.

In addition, the command for setting the cost regenerative torque to "0" in the vehicle controller 2 in the step 20 is applied to the motor controller 3 after the step S30.

When the vehicle speed is less than the speed value F, the cost regenerative torque applied to the motor must be "0" (step S20). Accordingly, the command in step S30 in which the existing Cost Regency Torque is maintained is changed so that "Costrgen Torque = 0". As a result, in step S31, the motor controller 3 applies the "regenerative braking command + cost regenerative torque command (=0)" for the motor torque when the vehicle speed <F.

As described above, according to the motor torque control method for improving braking linearity during regenerative braking of a hybrid vehicle of the present invention, the brake controller, the vehicle controller, and the motor controller control the amount of braking according to the brake depth under cooperative control. By making braking by the braking forces, as shown in Fig. 4, even when the vehicle speed decreases, the cost regenerative torque at the time of stepping on the brake (area marked in green) is kept constant, so that when the brake depth is the same, a constant deceleration rate Linearity is secured. In addition, at the end of regenerative braking, the cost regenerative torque maintained is reduced to 0Nm, and the frictional braking is increased by the reduced amount of the cost regenerative torque to maintain the deceleration.

The present invention can be applied to a hybrid vehicle without a separate additional device so as to improve braking linearity under cooperative control of a brake controller, a vehicle controller, and a motor controller in the amount of braking according to the brake depth.

1: brake controller 2: vehicle controller
3: motor controller 5: shift controller

Claims (10)

When the driver presses the brake pedal (On), the brake controller 1 calculates and distributes the braking amount A according to the brake depth (depth) (S1),
Comparing the speed of the vehicle from the signal of the vehicle speed sensor to a preset speed value (E) (S2),
If the vehicle speed is greater than a preset speed value, calculating the allowable amount of regenerative braking in the brake controller 1 and providing it to the vehicle controller 2 (S3),
In the vehicle controller 2, receiving the allowable regenerative braking amount from the brake controller 1 and transmitting the regenerative braking command C to the motor controller 3 (S4),
Calculating a regenerative braking execution amount (D) according to the regenerative braking command (S5),
The brake controller transmits a friction braking command of the value obtained by subtracting the regenerative braking execution amount (D) calculated in the step (S5) from the braking amount (A) calculated in the step (S1) to the hydraulic pump under the control of the brake controller. Step (S6),
In accordance with the command in the step (S6), the frictional braking is applied by the hydraulic pressure by the hydraulic pump (S7),
When the driver presses the brake pedal (On), the vehicle controller 2 transmits a command (G) to maintain the cost regenerative torque at the time of the brake on to the motor controller 3 (S30). Motor torque control method, characterized in that. The method of claim 1, further comprising the step (S8) of comparing the vehicle speed according to the speed signal from the vehicle speed sensor and a preset speed value (F) following the step (S7), and a speed value at which the vehicle speed is set in the step (S8). F) If it is larger than the step of confirming the on/off of the brake again (S9), when the brake is in the off state, the vehicle controller (2) sends the cost regenerative torque command corresponding to the current vehicle speed to the motor controller (3). The motor torque control method further comprises a step of transmitting (S11), and a step of applying the motor torque by the motor controller (3) (S12). The method of claim 2, further comprising the step (S10) of setting the braking amount according to the brake depth to "0" in the brake controller (1) when the brake is off in the step (S9). Motor torque control method. The motor torque control method according to claim 2, wherein when the brake is turned on in the step (S9), the steps (S1 to S8) are repeatedly performed by returning to the step (S1). The motor torque control method according to claim 2, further comprising the step (S21) of setting the allowable amount of regenerative braking to "0" when the vehicle speed is less than the set speed value (F) in the step (S8). . The method of claim 5, wherein the setting of the allowable regenerative braking amount to "0" in the step (S21) is characterized in that the braking amount according to the brake depth calculated by the brake controller in the step (S1) is performed by hydraulic pressure. Motor torque control method. 6. The motor torque control method according to claim 5, wherein in the step (S21), the brake controller transmits the setting of the allowable regenerative braking amount to "0" to the vehicle controller prior to the step (S4). The method of claim 5, wherein the brake controller transmits the Coast Regen torque compensation friction braking command (B) to the hydraulic pump under the control of the brake controller as the allowable regenerative braking amount is set to "0" in the step (S21). Motor torque control method, characterized in that it further comprises. delete The method of claim 1, wherein the cost regenerative torque maintenance command (G) in the step (S30) and the regenerative braking command (C) in the step (S4) are transmitted to the motor controller so that the motor torque (G+C) is applied. Motor torque control method, characterized in that.

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