KR101294126B1 - Regenerative braking system - Google Patents

Abstract

The present invention relates to a regenerative braking system, and in particular, the present invention maximizes the recovery of regenerative energy because a variable friction braking amount can be realized by using a hydraulic brake system for front wheel braking and an electromechanical brake system for rear wheel braking. It is possible to minimize braking heterogeneity due to excellent response and control performance by braking by electric motor method.

Description

Regenerative braking system {REGENERATIVE BRAKING SYSTEM}

The present invention relates to a regenerative braking system, and more particularly, to a regenerative braking system for charging a battery by regenerative braking during vehicle braking.

The regenerative braking system is one of the nuclear chamber technology of electric vehicles driven by electric energy, such as a hybrid electric vehicle (HEV), an electric vehicle (EV), and a fuel cell electric vehicle (FCEV).

The regenerative braking system is a device that recovers the electric energy generated by driving the motor with kinetic energy as a battery, unlike the kinetic energy of the vehicle being released as frictional heat energy in order to increase the driving distance and efficiency of HEV, EV, and FCEV. It is essential for improving fuel economy.

When braking an electric vehicle to which the regenerative braking system is applied, it is necessary to determine whether to give priority to regenerative braking or general friction braking according to the driving condition of the vehicle and the driver's willingness to braking. In this case, it should be possible to control how much each size is made. The higher the rate of regenerative braking, the higher the energy recovery, but the regenerative braking needs to be limited according to the state of charge of the battery and the temperature of the motor.In this situation, if the regenerative braking power is not controlled, the motor or battery may be fatally damaged. do. On the other hand, if the regenerative braking force is not sufficient, the general friction braking force must be increased to satisfy the driver's deceleration demand.

Therefore, the regenerative braking system using the conventional hydraulic brake system has been applied to soft type electric vehicles with small motor capacity, and the distribution ratio of regenerative braking and friction braking is fixed according to the vehicle speed. This is limited.

In addition, the regenerative braking system using the conventional hydraulic brake system generates a heterogeneity of braking when the regenerative braking transition section is generated due to a difference in the responsiveness between the hydraulic braking force of the hydraulic brake and the regenerative braking force of the vehicle driving motor.

An object of the present invention is to use a hydraulic brake system for braking the front wheel and an electromechanical brake system (EMB system) for braking the rear wheel to maximize the recovery of regenerative energy and to minimize the regenerative sense of braking. to provide.

According to an aspect of the present invention, a rotary braking system mounted on an electric vehicle, comprising: a fuel cell used as a main power source; A battery used as an auxiliary power source; A driving motor which receives power from the fuel cell and drives at least one of a front wheel and a rear wheel; A reduction gear configured to receive a rotational force of the driving motor and provide the at least one of the front wheel and the rear wheel; An inverter configured to convert the DC voltage provided from the fuel cell into a three-phase voltage to drive the driving motor, and to charge the battery with regenerative energy recovered from the driving motor when braking the electric vehicle; Hydraulic disc brakes mounted on the front wheels; A hydraulic module for providing a braking pressure to the hydraulic disc brake; An EMB actuator mounted on the rear wheel to generate a braking force by operating a caliper by a motor; An EMB ECU for controlling the operation of the EMB actuator; And operating the hydraulic disc brake through the hydraulic module to brake the front wheel and regenerative braking by the driving motor when braking the electric vehicle, and communicating with the EMB ECU to operate an EMB actuator to operate the rear wheel. A central ECU configured to brake the EMB; wherein the central ECU determines the regenerative braking force and the EMB braking force according to the state of the vehicle, controls the EMB braking force according to the regenerative braking force, and the EMB ECU regenerates with the central ECU. The regenerative braking system may include providing a braking force obtained by subtracting the regenerative braking force due to the regenerative braking of the driving motor and the hydraulic braking force due to the hydraulic braking.

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According to another aspect of the present invention, a rotary braking system mounted on an electric vehicle, comprising: a fuel cell used as a main power source; A battery used as an auxiliary power source; A driving motor which receives power from the fuel cell and drives at least one of a front wheel and a rear wheel; A reduction gear configured to receive a rotational force of the driving motor and provide the at least one of the front wheel and the rear wheel; An inverter configured to convert the DC voltage provided from the fuel cell into a three-phase voltage to drive the driving motor, and to charge the battery with regenerative energy recovered from the driving motor when braking the electric vehicle; Hydraulic disc brakes mounted on the front wheels; A hydraulic module for providing a braking pressure to the hydraulic disc brake; An EMB actuator mounted on the rear wheel to generate a braking force by operating a caliper by a motor; An EMB ECU for controlling the operation of the EMB actuator; And operating the hydraulic disc brake through the hydraulic module to brake the front wheel and regenerative braking by the driving motor when braking the electric vehicle, and communicating with the EMB ECU to operate an EMB actuator to operate the rear wheel. And a central ECU configured to brake the EMB, wherein the central ECU determines the regenerative braking force and the EMB braking force according to the state of the vehicle, controls the EMB braking force according to the regenerative braking force, and the EMB actuator is coupled to the rear wheel. A motor for moving the pads spaced apart from one side of the disk, a speed reducer provided between the motor and the pad to reduce the rotational speed of the motor and to increase the braking force, and a rotational motion of the speed reducer provided between the speed reducer and the pad. To transfer the braking torque to the pad by braking force There is a regenerative braking system including a can be provided.

Existing regenerative braking system has been applied to soft type HEV with small motor capacity, and the distribution ratio of regenerative braking and friction braking is fixed according to vehicle speed, but EMB type regenerative braking system according to the embodiment of the present invention is hard type electric. It can be applied to automobiles and the variable friction braking amount can be implemented to maximize the recovery of regenerative energy.

In addition, in the conventional regenerative braking system, a heterogeneity of braking may occur when a regenerative braking transition section occurs due to a difference in responsiveness between the hydraulic braking force of the hydraulic brake and the regenerative braking force of the vehicle driving motor, but the regenerative braking system of the EMB type according to the embodiment of the present invention. Because of the EMB braking of the rear wheels, this problem can be minimized by excellent response and control performance.

In addition, the regenerative braking system of the EMB type according to the embodiment of the present invention can ensure vehicle safety and improve braking performance.

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

The regenerative braking system according to an embodiment of the present invention refers to a whole braking device whose primary purpose is to improve fuel efficiency through charging of an auxiliary power source during braking. It is a fusion technology that combines technology with electric vehicles.

The regenerative braking system according to an embodiment of the present invention can maximize fuel efficiency and secure vehicle stability through optimized cooperative control of regenerative braking force and brake braking force of a drive motor.

When comparing the fuel consumption between the existing vehicle and the fuel cell vehicle, it is possible to confirm the improvement of fuel economy by regenerative braking, which depends on how much the regenerative braking energy is recovered. Therefore, the regenerative braking cooperative control system that controls the regenerative braking and braking ratio in consideration of the system situation (secondary power charging amount, vehicle speed, etc.) is an essential core technology required for not only fuel cell vehicles but also eco-friendly vehicles.

In addition to regenerative braking, there are limitations to existing hydraulic braking systems in order to incorporate advanced technologies in vehicle stability and steering, and application of electromechanical systems is essential. This requires a braking device capable of active control to reduce the braking force as much as the regenerative braking torque in order to maximize the storage of the kinetic energy into electrical energy by the regenerative braking of the motor during the braking to store in the battery.

Accordingly, an embodiment of the present invention proposes a regenerative braking system incorporating an EMB system. Accordingly, in the embodiment of the present invention, by regulating the regenerative braking cooperation system by linking the EMB operation with the regenerative braking operation, the regenerative energy recovered in the battery can be maximized and the driver's safety can be secured.

1 shows a configuration of a regenerative braking system applied to an electric vehicle according to an embodiment of the present invention.

As shown in FIG. 1, the rear wheels RR and RL of the electric vehicle are equipped with an EMB actuator 10 that generates a braking force by operating a caliper equipped with a motor, and the front wheels are provided with brake fluid provided by a hydraulic module. A hydraulic disc brake 20 for generating hydraulic braking force is mounted.

The EMB actuator 10 can improve the dynamic behavior, braking performance, and responsiveness of the vehicle compared to the hydraulic disc brake 20. Since the EMB actuator sends a signal directly from the EMB ECU, which will be described later, the hydraulic disc brake 20 It is possible to control the speed of the vehicle more accurately.

The electric vehicle is supplied with power by the fuel cell 30 to drive the motor 40, which is an electric motor that generates the driving force of the electric vehicle, and the DC voltage applied to the drive motor 40 by switching to convert to a three-phase voltage Drives the drive motor 40 and reduces the rotational force of the inverter 50 for supplying the regenerative energy recovered from the drive motor 40 to the battery 60 at a charging voltage and the drive motor 40 at a set ratio reduction ratio. A reducer 70 is provided for the front wheel.

When the electric vehicle is accelerated, the DC voltage of the fuel cell is supplied to the inverter and converted into a three-phase voltage as in the direction of the arrow, and then supplied to the driving motor 40 to drive the driving motor 40, by the reducer 70. The electric vehicle runs by being decelerated at a predetermined ratio and transmitted to the front wheel which is the driving wheel.

At the time of deceleration or braking of the electric vehicle, power generated by the drive motor 40 by the regenerative braking operation of the drive motor 40 is charged in the battery 60 via the inverter 50 as shown in the arrow direction.

2 shows an EMB actuator of a regenerative braking system according to an embodiment of the present invention.

As shown in FIG. 2, the EMB actuator 10 includes a motor 11, a reducer 12, and screw screw gears 13, 14. The motor 11 supplies a braking force as a DC motor, and the reducer 12 reduces the rotational speed of the motor 11 by using planetary gears and increases the braking force. The screw screw gears 13 and 14 convert the braking torque into the braking force by converting the rotational movement into a linear movement.

This EMB actuator 10 is coupled to the disc brake module 200.

The disc brake module 200 includes a pad 201, a disc 202, a torque member 203 (Torque member), and a caliper housing 204. The pad 201 is located on both sides of the disk 202 and generates a frictional force by compressing the disk 202 connected to the wheel by using a caliper the force transmitted from the head 14 of the EMB actuator 10. The disk 202 is rotated in a state fixed to the hub or drive shaft of the wheel to generate a braking force by friction with the pad 201 during braking. The torque member 203 implements an interlocking action such that when the pad 201 (inner pad) is pressed to the disk 202 side, the pad 201 (outer pad) located on the opposite side thereof is also moved to the disk 202 side. The caliper housing 204 surrounds the disk 202 of each wheel and forms a space for the pad 201 moved by the screw screw gears 13 and 14 to be pressed against the disk 202.

The motor 11 of the EMB actuator 10 generates torque by converting electrical energy into mechanical rotational energy. The motor 11 includes an AC motor using an alternating current and a DC motor using a direct current. Among them, the DC motor has the advantage of being capable of speed control that requires a wide range and high precision, and good efficiency in torque control that can arbitrarily select starting torque and acceleration torque. The characteristics of this DC motor are suitable for EMB, which must accurately follow the target braking force during braking and easily adjust the braking force.

The reducer 12 increases the transmission torque of the motor 11 and serves to reduce the speed. The speed reducer 12 is disposed, for example, on the concentric line with the rotation shaft of the motor 11 using planetary gears as planetary gear heads 12. The planetary reducer 12 is much used because of its smaller size, input / output on the same axis, and higher efficiency than other gear trains.

The screw screw gears 13 and 14 consist of a male screw and a female screw. Skew screw gear is used to obtain the braking force by pushing the pad 51 to the disk 52 by converting the rotational movement transmitted from the shorthand to the external thread to the linear motion of the female thread. In the embodiment of the present invention, the male screw connected to the carrier of the reducer 12 is divided into a screw 13 and a female screw pushing the pad 51 into the heads 14 and 14.

Looking at the EMB operation in the regenerative braking system according to the embodiment of the present invention having the above configuration, the force due to the rotation of the motor 11 during the EMB braking operation to the inner pad 201 through the head 14 in the direction of the arrow disc Close to 202. Once the pad 201 is in close contact with the disk 202, the head 14 can no longer advance. When the caliper housing 204 connected to the main body of the motor 11 is pushed backward by the half operation, the outer pad 201 is pulled to squeeze the pad 201 to the disk 202. By this action, the outer pad 201 and the inner pad 201 are simultaneously pressed onto the disk 202, and the disk 202 is braked by friction.

When the EMB brake is released, the reverse rotation of the motor 11 causes the screw 13 to enter the inside of the head 14 and act on the caliper housing 204 and the compressive force of the disk 202 of the outer pad 201, the inside. As the compression force of the disk 202 of the pad 201 is lost, the braking force is released and the head 14 returns to its original position to maintain a constant distance from the disk 202.

3 shows a control block of a regenerative braking system according to an embodiment of the present invention.

As shown in FIG. 3, the central ECU 100 brakes the hydraulic disc brake through the hydraulic module 90 according to various sensing information such as the braking intention of the driver input through the sensor unit 110. 20) to hydraulically brake the front wheels (FR, FL). At this time, regenerative braking by the driving motor 40 is performed together. In addition, the central ECU 100 transmits a control signal for EMB braking to the EMB ECU 80. The EMB ECU 80 brakes the rear wheels RR and RL via the EMB actuator 10 in accordance with this control signal.

The central ECU 100 determines the regenerative braking and the EMB braking amount by receiving the state of the vehicle such as the driver's braking intention, driving state of the vehicle, battery charging state, and motor characteristics. Here, the higher the rate of regenerative braking, the higher the energy recovery, but if the proper regenerative braking force is not controlled, the driving motor 40 or the battery 60 may be fatally damaged. When the regenerative braking amount is determined, the central ECU controls the operation of the driving motor 40 through the inverter 50 to brake the vehicle so that the regenerative braking amount is generated. The EMB ECU receives the driver's braking intention by operating the brake pedal (BP) from the central ECU and generates some of the remaining braking force except for the regenerative braking force determined by the regenerative braking algorithm through the EMB actuator 10 mounted on the rear wheel. Let's do it.

Hydraulic braking is applied to the front wheel of the electric vehicle to which the regenerative braking system according to the embodiment of the present invention is applied, and electric braking is performed to the rear wheel. The detailed configuration is in terms of the wheels, and the front wheels are equipped with Electronic Stability Control (ESC) that enables active braking to the basic CBS (Conventional Brake System). It consists of the EMB actuator 10.

The front wheel has a central ECU 100 and a hydraulic module 90 for controlling the ESC, and the existing hydraulic line is also connected to operate at the time of fail. The rear wheels are driven by an electronically driven motor, with a corresponding motor driver. An EMB ECU 80 is mounted for control of these, and the EMB ECU 80 is provided with a sensor for measuring a current for estimating the force of the motor 11 of the EMB actuator 10, and the ABS / Active control functions other than TCS / ESC can be performed. And, for these ESC control, various sensors (steering angle sensor, yaw rate sensor, lateral acceleration sensor, wheel speed sensor, pedal travel sensor, etc.) are configured.

In the regenerative braking system according to an embodiment of the present invention, the front wheel may be configured as a hydraulic disc brake 20 to perform basic braking, active braking, and regenerative braking, and the rear wheel may be configured as an EMB actuator 10 to provide basic braking and active braking. Braking, regenerative braking and auxiliary braking are available.

When the brake pedal BP is operated by the driver's will, the front wheels are braked by hydraulic compression, and according to the operation of the brake pedal BP, the central ECU 100 recognizes the driver's braking intention and applies the required EMB braking force. The calculation causes the EMB ECU 80 to operate the EMB actuator 10 to cause the rear wheels to EMB brake.

The rear wheel braking recognizes the driver's braking intention by the driver's braking intention and obtains the braking force corresponding to the will and each wheel braking corresponding to each wheel, and calculates each wheel force through the EMB ECU 80. Implemented through EMB actuator control.

When a function such as ABS / TCS / ESC is activated in response to the sensor input, the front wheel performs control commands in the ESC using hydraulic pressure and the rear wheel in logic of the EMB ECU 80.

If a failure occurs due to a failure of the hydraulic module 90 or the central ECU 100 or a battery discharge, the front wheel is hydraulically operated, and braking is performed by the force of the driver's foot. That is, the back-up function is performed through the front wheel hydraulic line. This function helps you prepare for an emergency.

Regenerative braking is achieved by front wheel hydraulic regenerative control when driving the front wheel, and rear wheel EMB regenerative control when driving the rear wheel.

1 is a block diagram of a regenerative braking system applied to a fuel cell vehicle according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of the EMB actuator shown in FIG. 1.

3 is a control block diagram of a regenerative braking system according to an embodiment of the present invention.

[Description of the Reference Numerals]

10: EMB actuator 20: hydraulic disc brake

30: fuel cell 40: motor

50: inverter 60: battery

70: reducer 80: EMB ECU

90: hydraulic module 100: central ECU

110: sensor unit

Claims (3)

delete In a rotating braking system mounted on an electric vehicle, A fuel cell used as a main power source; A battery used as an auxiliary power source; A driving motor which receives power from the fuel cell and drives at least one of a front wheel and a rear wheel; A reduction gear configured to receive a rotational force of the driving motor and provide the at least one of the front wheel and the rear wheel; An inverter configured to convert the DC voltage provided from the fuel cell into a three-phase voltage to drive the driving motor, and to charge the battery with regenerative energy recovered from the driving motor when braking the electric vehicle; Hydraulic disc brakes mounted on the front wheels; A hydraulic module for providing a braking pressure to the hydraulic disc brake; An EMB actuator mounted on the rear wheel to generate a braking force by operating a caliper by a motor; An EMB ECU for controlling the operation of the EMB actuator; And When the electric vehicle is braked, the hydraulic disc brake is operated through the hydraulic module to brake the front wheels hydraulically and perform regenerative braking by the driving motor, and communicate with the EMB ECU to operate the EMB actuator to operate the rear wheels. Including central ECU braking EMB, The central ECU determines the regenerative braking force and the EMB braking force according to the state of the vehicle, and controls the EMB braking force according to the regenerative braking force, The EMB ECU includes a regenerative braking system including generating a braking force obtained by subtracting the regenerative braking force due to regenerative braking of the driving motor and the hydraulic braking force due to the hydraulic braking among the braking force requested by the driver by regenerative braking cooperative control with the central ECU. . In a rotating braking system mounted on an electric vehicle, A fuel cell used as a main power source; A battery used as an auxiliary power source; A driving motor which receives power from the fuel cell and drives at least one of a front wheel and a rear wheel; A reduction gear configured to receive a rotational force of the driving motor and provide the at least one of the front wheel and the rear wheel; An inverter configured to convert the DC voltage provided from the fuel cell into a three-phase voltage to drive the driving motor, and to charge the battery with regenerative energy recovered from the driving motor when braking the electric vehicle; Hydraulic disc brakes mounted on the front wheels; A hydraulic module for providing a braking pressure to the hydraulic disc brake; An EMB actuator mounted on the rear wheel to generate a braking force by operating a caliper by a motor; An EMB ECU for controlling the operation of the EMB actuator; And When the electric vehicle is braked, the hydraulic disc brake is operated through the hydraulic module to brake the front wheels hydraulically and perform regenerative braking by the driving motor, and communicate with the EMB ECU to operate the EMB actuator to operate the rear wheels. Including central ECU braking EMB, The central ECU determines the regenerative braking force and the EMB braking force according to the state of the vehicle, and controls the EMB braking force according to the regenerative braking force, The EMB actuator is a motor coupled to the rear wheel to move the pads spaced apart on one side of the disk, a speed reducer provided between the motor and the pad to reduce the rotational speed of the motor and increase the braking force, the reducer and the And a gear provided between the pads to convert the rotational motion of the speed reducer into a linear motion to transfer the braking torque to the pads with braking force.

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