KR20190143588A - Electric brake system - Google Patents

Abstract

An electronic brake system is disclosed. According to an embodiment of the present invention, in the electronic brake system generating a braking force in a wheel using the rotational force of a motor, the motor includes a three-phase coil, at least one of the three-phase coils includes a plurality of wires connected in parallel, and a current detector for detecting a flowing current is connected to any one of the plurality of wires.

Description

Electronic brake system {ELECTRIC BRAKE SYSTEM}

The present invention relates to an electronic brake system, and more particularly to an electronic brake system including a motor operated by an electrical signal corresponding to the displacement of the brake pedal.

Recently, an electronic brake system for generating a braking force on a wheel by using a rotational force of a motor has been developed.

The electronic brake system senses the driver's braking intention from the brake pedal to generate braking force through the position and current control of the motor.

For example, an electronic brake system uses a motor to generate a high pressure brake pressure using a vacuum to generate a braking force instead of a booster that boosts the brake pedal force using a vacuum. The electronic brake system senses when the driver presses the brake pedal and opens or closes each valve to create a path through which pressure is delivered, and generates braking force by using a motor to create high pressure hydraulic pressure that is transmitted to each wheel.

The vehicle braking force generating device disclosed in Japanese Patent Application Laid-Open No. 2014-019344 uses a method of installing a shunt resistor on the current path to the motor winding as a current sensor for controlling the motor and measuring the voltage across the shunt resistor. To monitor the phase current flowing through the motor windings.

However, monitoring current by inserting a shunt resistor in the current path to the motor winding as in the conventional method is useful for small-capacity motors with relatively small currents, but for large-capacity motors with relatively large currents, Since the amount of heat generation increases considerably and the size of the shunt resistor package increases, additional heat dissipation measures are required, and the size of the printed circuit board (PCB) where the shunt resistor package is installed is also relatively large, making it impossible to miniaturize the system. There is this.

Japanese Laid-Open Patent Publication No. 2014-019344 (2014.02.03.)

An embodiment of the present invention is to provide an electronic brake system that can reduce the amount of heat generated by the shunt resistor and the size of the resistor package for detecting the phase current of the motor.

According to an aspect of the present invention, in the electronic brake system for generating a braking force on the wheel by using the rotational force of the motor, the motor includes a three-phase coil, at least one of the three-phase coil is a plurality of parallel connected An electronic brake system including a winding and connected to a current detector for detecting a current flowing in any one of the plurality of windings may be provided.

In addition, the current detector may include a shunt resistor connected in series to any one of the plurality of windings.

The control unit may further include an electronic control unit that calculates a current flowing through the winding using the voltage across the shunt resistor, and calculates a phase current flowing through the coil using impedances of the windings connected in parallel in the coil.

According to another aspect of the present invention, in the electronic brake system comprising a hydraulic pressure supply device for generating a hydraulic pressure by moving the piston by using the rotational force of the motor and supplying the generated hydraulic pressure to the wheel cylinder provided on each wheel, wherein the motor is A three-phase coil, wherein at least one coil of the three-phase coil includes a plurality of windings connected in parallel, the shunt resistor for detecting a current flowing in any one of the plurality of windings may be connected in series.

The control unit may further include an electronic control unit that calculates a current flowing through the winding connected to the shunt resistor using the voltage across the shunt resistor, and calculates a phase current flowing through the coil using impedances of the windings connected in parallel in the coil. have.

Embodiments of the present invention can reduce the amount of heat generated by the shunt resistor and the size of the resistor package for detecting the phase current of the motor.

1 is a schematic configuration diagram of an electronic brake system according to an embodiment of the present invention.
2 is a schematic control block diagram of an electronic brake system according to an embodiment of the present invention.
3 is a view showing a winding structure of a motor in an electronic brake system according to an embodiment of the present invention.
4 is a view for explaining the detection of the phase current of the motor using the shunt resistor provided in the winding of the motor in the electronic brake system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments introduced below are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art to which the present invention pertains. The present invention is not limited to the embodiments described below and may be embodied in other forms. Parts not related to the description are omitted in the drawings in order to clearly describe the present invention, in the drawings, the width, length, thickness, etc. of the components may be exaggerated for convenience. Like numbers refer to like elements throughout.

1 is a schematic configuration diagram of an electronic brake system according to an embodiment of the present invention.

Referring to FIG. 1, the electronic brake system 1 includes a reservoir 10, a master cylinder 20, a wheel cylinder 30, a hydraulic pressure supply device 40, a hydraulic control device 50, and an electronic control unit (ECU). 60 may be included.

The master cylinder 20 is connected to the reservoir 10 and discharges oil according to the stepping force of the brake pedal P. FIG.

The wheel cylinder 30 performs braking of each wheel RR, RL, FR, FL by the transmitted hydraulic pressure.

The hydraulic pressure supply device 40 is connected to the master cylinder 20 to generate a hydraulic pressure by moving the piston using the rotational force of the motor.

For example, the hydraulic pressure supply device 40 includes a cylinder block 41 in which a pressure chamber for receiving and storing oil is formed, a hydraulic piston 42 accommodated in the cylinder block 41, and the hydraulic piston 42. It may include a motor 43 for providing power to the hydraulic piston 42 at the rear end. The motor 43 generates a rotational force by the control signal of the electronic control unit 60. The motor 43 may include a stator 43a and a rotor 43b to generate rotational force in the forward or reverse direction.

In addition, the hydraulic pressure supply device 40 is formed by the worm shaft 44 integrally formed with the rotation shaft of the motor 43, the worm wheel 45 rotating by the worm shaft 44, and the rotation of the worm wheel 45. It may include a drive shaft 46 for linearly moving to slide the hydraulic piston 42 in the cylinder block (41). In addition, the hydraulic pressure supply device 40 may include various valves for switching the flow path.

Looking at the operation of the hydraulic pressure supply device 40, when a displacement occurs in the brake pedal (P), the detection signal is transmitted to the electronic control unit (ECU) by a pedal displacement sensor for detecting the displacement of the brake pedal (P). The electronic control unit 60 drives the motor 43 in one direction to rotate the worm shaft 44 in one direction. The rotational force of the worm shaft 44 is transmitted to the drive shaft 46 via the worm wheel 45, and the hydraulic piston 42 connected to the drive shaft 46 moves forward to generate hydraulic pressure in the pressure chamber of the cylinder block 111. . The generated hydraulic pressure is transmitted to the hydraulic control device 40 by the operation of various valves for switching the flow path.

The hydraulic control device 40 transmits the hydraulic pressure generated by the hydraulic pressure supply device 30 to the wheel cylinders 30 provided on the respective wheels RR, RL, FR, and FL. The hydraulic controller 40 includes various valves for changing the flow path. These valves are opened and closed by the electronic control unit 60.

The electronic control unit 60 may control the hydraulic pressure supply device 40 and the hydraulic control device 50 using the displacement information of the brake pedal P and the pressure information of each wheel cylinder.

2 is a schematic control block diagram of an electronic brake system according to an embodiment of the present invention.

Referring to FIG. 2, the electronic brake system 1 may include an electronic control unit 60 that performs overall control.

The electronic control unit 60 performs an operation necessary for controlling the electronic brake system by using the memory for storing the data for the algorithm or the program that reproduces the algorithm and the data stored in the memory. It can be implemented with a microprocessor. In this case, the memory and the processor may be implemented as separate chips. Alternatively, the memory and the processor may be implemented in a single chip.

The electronic control unit 60 may control various valves included in the electronic brake system 1 including the motor 43.

An inverter 70 for driving the motor 43 is electrically connected to the output side of the electronic control unit 60.

A pedal displacement sensor 80 for detecting displacement of the brake pedal P and a current detector 90 for detecting a current flowing in the motor 43 are electrically connected to an input side of the electronic control unit 60.

The pedal displacement sensor 80 is provided in the brake pedal P to detect the operation and displacement of the brake pedal P. The pedal displacement information detected by the pedal displacement sensor 80 is transmitted to the electronic control unit 60.

The current detector 90 detects a current flowing in any one of three phases of the motor 43. Motor current information detected by the current detector 90 is transmitted to the electronic control unit 60.

The electronic control unit 60 controls various valves included in the electronic brake system 1 including the motor 43 according to the brake pedal displacement information detected through the pedal displacement sensor 80 during braking operation.

The electronic control unit 60 controls the operation of the motor 43 by controlling the inverter 70 according to the motor current detected through the current detector 90 while operating the motor 43.

The inverter 70 may be electrically connected to a vehicle battery B +, which is a DC power supply, and a capacitor C, which smoothes a signal. The capacitor C is connected in parallel to the vehicle battery B. The capacitor C smoothes the power supplied from the vehicle battery B +. The power smoothed by the capacitor C is supplied to the inverter 90.

The inverter 70 is to drive the motor 43 by converting the DC power of the vehicle battery B into a pulse-shaped three-phase alternating current having an arbitrary variable frequency through pulse width modulation (PWM). It may include a plurality of power switching elements and a plurality of diodes. For convenience of description, the inverter 70 includes six power switching elements Q1 to Q6 and six diodes D1 to D6.

The power switching elements Q1 to Q6 include an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field-effect transistor (MOS FET), a transistor (Tr), and the like. It may include. The power switching elements Q1 to Q6 are turned on or off by the control signal of the electronic control unit 50. The diodes D1-D6 are connected in parallel to each IGBT so as to flow current from the emitter side of the IGBT to the collector side when the power switching element is an IGBT.

The six power switching elements Q1-Q6 are paired in series and connected to the phase terminals of the motor 43, respectively. The upper switching elements Q1, Q3 and Q5 are connected to the positive terminal of the DC power supply, and the lower switching elements Q2, Q4 and Q6 are connected to the negative terminal of the DC power supply. That is, the first power switching element Q1 and the second power switching element Q2 are the third power switching element Q3 and the fourth power switching element Q4 so as to correspond to the phases of the U phase, the V phase, and the W phase. The fifth power switching element Q5 and the sixth power switching element Q6 are connected in series, respectively.

The inverter 70 is connected to each phase terminal of the motor 43 which is a three-phase motor.

The inverter 70 turns on or off each power switching element Q1-Q6 in accordance with the control signal output by the electronic control unit 60 to convert the current supplied from the vehicle battery B + into a direct current from a direct current. Is converted to and supplied to the motor 43. At this time, the voltage of the vehicle battery B + may be boosted by the converter and supplied to the inverter 70.

The electronic control unit 60 drives the motor 43 by operating the inverter 70 based on various information detected by the pedal displacement sensor 80 and the current detector 90.

The electronic control unit 60 controls the operation of the motor 43 by controlling the turn-on and turn-off of each power switching element Q1-Q6 of the inverter 70 based on the motor phase current detected by the current detector 90. To control. In this case, the electronic control unit 60 may control the turn on or turn off of each power switching element Q1 to Q6 by PWM control.

3 is a view showing the winding structure of the motor in the electronic brake system according to an embodiment of the present invention, Figure 4 is a motor using a shunt resistor provided in the winding of the motor in the electronic brake system according to an embodiment of the present invention It is a figure for demonstrating detecting phase current of.

3 and 4, the motor 43 is a three-phase motor, and each phase terminal is connected to the inverter 70.

The motor 43 includes a U-phase coil Lu, a V-phase coil Lv, and a W-phase coil Lw. The U-phase coil Lu, the V-phase coil Lv, and the W-phase coil Lw can form a Y connection.

In the motor 43, an alternating current having a 120 degree phase difference supplied from the inverter 70 is energized to each phase coil Lu, Lv, and Lw. Thereby, the rotating shaft of the motor 43 rotates.

Each phase coil Lu, Lv and Lw consists of parallel windings respectively.

Each phase coil Lu, Lv and Lw each comprises a plurality of windings connected in parallel. For example, in each phase coil Lu to Lw, two windings are connected in parallel. In the Lu phase coil, two windings Lu1 and Lu2 are connected in parallel. In the Lv phase coil, two windings Lv1 and Lv2 are connected in parallel. In the Lw phase coil, two windings Lw1 and Lw2 are connected in parallel.

The current detector 90 may include a shunt resistor 91 and a differential amplifier 92.

The shunt resistor 91 may be connected to any one of each phase coil Lu, Lv, and Lw.

The shunt resistor 91 is provided in one of the phase coils Lu, Lv, and Lw, and may be connected to any one of the plurality of windings of the phase coil.

For example, the shunt resistor 91 may be connected to the second U-phase winding Lu2 of the first U-phase winding Lu1 and the second U-phase winding Lu2 of the U-phase coil Lu. The shunt resistor 91 may be inserted into the second U-phase winding Lu2 and connected in series with the second U-phase winding Lu2.

The differential amplifier 92 is connected to both ends of the shunt resistor 91.

The differential amplifier 92 is configured to amplify the voltage difference across the shunt resistor 91. The voltage V0 output from the differential amplifier 92 is transmitted to the electronic control unit 60.

The electronic control unit 60 may calculate the current flowing through the shunt resistor 91 using the voltage V0 provided from the differential amplifier 92.

The electronic control unit 60 can calculate the phase current of the motor 43 by calculating the current flowing through the shunt resistor 91.

Hereinafter, the calculation of the phase current I0 of the motor 43 using the shunt resistor 91 will be described.

In FIG. 4, in the U-phase coil, the impedance between point a and point b is Zab, the impedance Zbc between point b and point c, the impedance between point a and point c is Zac, and V0 is the output voltage of differential amplifier 92. , AG is the gain of the differential amplifier, I0 is the phase current of the motor, Ia is the current flowing in the first Lu winding Lu1, Ib is the current flowing in the second Lu winding Lu2.

Zac = Zab,

The voltage Vac between point a and point c can be expressed by the following equation [1].

Vac = (Zab + Zbc) * Ib = (Zac) * Ia-equation [1]

Ia = Vac / Zac, Ib = Vac / (Zab + Zbc), I0 = Ia + Ib,

The sum of the impedances of Zac and Zbc Zac ∥ Zbc is [{(Zab + Zbc) * Zac} / (Zab + Zbc + Zac)]. + 2Zbc} / (Zab + 2Zbc).

Since the output voltage V0 of the differential amplifier 92 is input to the electronic control unit 60, the electronic control unit 60 can calculate the motor phase current I0 by the following formula [2].

I0 = V0 * AG * (Zab + Zbc) / (Zac∥Zbc)-equation [2]

If the Zac ∥ Zbc in the formula [1] is {(Zab + Zbc) * Zbc + 2Zbc} / (Zab + 2Zbc) and substituted in the formula [2], the motor phase current I0 can be summarized by the following formula [3].

I0 = V0 * AG * (Zab + Zbc) * (Zab + 2Zbc) / {(Zab + Zbc) * Zbc + 2Zbc}-expression [3]

The electronic control unit 60 controls the current of the motor 43 by monitoring the motor phase current IO, thereby forming hydraulic pressure by the input / output of the hydraulic piston 42 of the hydraulic pressure supply device 40, thereby ensuring braking performance. Can be.

As described above, by providing the shunt resistor 91 for detecting the phase current of the motor 43 in any one of the parallel windings of the respective phase coils, the motor current flowing through the shunt resistor 91 can be relatively reduced. Therefore, the power consumption of the shunt resistor 91 can be reduced, so that the amount of heat generated by the shunt resistor 91 can be greatly reduced, and the size of the shunt resistor package can be reduced, thereby reducing the size of the printed circuit board. As a result, the system can be miniaturized and manufacturing costs can be reduced. In addition, by applying to the electronic brake system of a large vehicle employing a large-capacity motor can further reduce the size and heat generation of the shunt resistor package can be expected a greater effect.

In the above embodiment, an electronic brake system including a hydraulic pressure supply device for generating a hydraulic pressure by moving a piston by using a rotational force of a motor is described, but is not limited thereto, and generates a braking force on a wheel by using a rotational force of a motor. The same applies to the electronic brake system.

10: reservoir 20: master cylinder
30: wheel cylinder 40: hydraulic pressure supply device
43: motor 50: hydraulic control device
60: electronic control unit 70: inverter
80: pedal displacement sensor 90: current detector
91: shunt resistor 92: differential amplifier

Claims (5)

In the electronic brake system for generating a braking force on the wheel by using the rotational force of the motor,
The motor comprises a three phase coil, at least one of the three phase coils comprises a plurality of windings connected in parallel,
And an electric current detector for detecting a current flowing in any one of the plurality of windings. The method of claim 1,
And the current detector includes a shunt resistor in series with one of the plurality of windings. The method of claim 2,
And an electronic control unit configured to calculate a current flowing through the winding using the voltages across the shunt resistor, and calculate a phase current flowing through the coil using impedances of the windings connected in parallel in the coil. In the electronic brake system including a hydraulic pressure supply device for generating a hydraulic pressure by moving the piston using the rotational force of the motor and supplying the generated hydraulic pressure to the wheel cylinder provided on each wheel,
The motor comprises a three phase coil, at least one of the three phase coils comprises a plurality of windings connected in parallel,
And an shunt resistor connected in series to detect a current flowing in one of the plurality of windings. The method of claim 4, wherein
An electronic brake system including an electronic control unit that calculates a current flowing through a winding connected to the shunt resistor using voltages across the shunt resistor, and calculates a phase current flowing through the coil using impedances of windings connected in parallel in the coil. .

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