KR20230024163A - Electro-mechanical Brake And Control Method Therefor - Google Patents

Abstract

Provided is an electric brake apparatus. According to one embodiment of the present disclosure, the electric brake apparatus comprises: a DC power source; a power sensor sensing a voltage of the DC power source; a control unit receiving and converting a DC current from the DC power source, and generating an AC current; and a motor receiving the AC current from the control unit. The control unit calculates a maximum power value which can be supplied to the motor based on the voltage of the DC power source, and sets a limit value of the current applied to the motor based on the maximum power value. According to the present invention, a phenomenon in which the voltage equal to or less than a threshold voltage is applied to the control unit can be prevented.

Description

Electric brake device and its control method {Electro-mechanical Brake And Control Method Therefor}

The present disclosure relates to an electric brake device.

The content described in this section simply provides background information for the present disclosure and does not constitute prior art.

When the driver of the vehicle presses the brake pedal, the control unit receives a depression amount using a pedal stroke sensor. The control unit controls the torque of the motor based on the amount of depression. The motor generates rotational force corresponding to the required braking pressure. The rotational force of the motor is converted into a force that translates the piston inside the master cylinder by a mechanism such as a cam and a gear. The piston inside the master cylinder generates hydraulic pressure inside the master cylinder while moving forward. The generated hydraulic pressure is transmitted to each wheel brake through a hydraulic line including a plurality of solenoid valves.

The motor receives an alternating current based on a signal from the control unit and generates rotational force corresponding to the required braking pressure. Since the power supplies DC current to the control unit, a power converter inside or outside the control unit converts the DC current into AC current and supplies it to the motor.

Internal resistance of the DC power source increases or the DC power source is discharged, so the amount of power that the DC power source can supply to the motor may be limited. When the amount of power that can be supplied to the motor is limited, if the current applied to the motor is increased, the voltage applied to the DC voltage input terminal of the control unit is reduced, causing the control unit to not function normally.

The electric brake device according to an embodiment may prevent a voltage lower than the threshold voltage from being applied to the control unit by setting a limit value of the current applied to the motor based on the voltage of the DC power supply.

The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

According to an embodiment of the present disclosure, a DC power source; A power sensor for detecting a voltage of a DC power supply; A control unit for receiving and converting DC current from a DC power source to generate AC current; and a motor receiving AC current from the control unit, wherein the control unit calculates a maximum power value that can be supplied to the motor based on the voltage of the DC power source, and a limit value of the current applied to the motor based on the maximum power value. Provides an electric brake device for setting.

According to another embodiment of the present disclosure, the process of determining whether current is being applied to the control unit; detecting a voltage value of a DC power source when current is not being applied to the control unit; Calculating the maximum power value that can be supplied to the motor based on the voltage of the DC power supply; And it provides an electric brake device control method comprising the step of setting a limit value of the current applied to the motor based on the maximum power value.

As described above, according to the present embodiment, by setting the limit value of the current applied to the motor based on the voltage of the DC power supply, it is possible to provide an electric brake device that prevents voltage below the threshold voltage from being applied to the control unit. .

1 is a block diagram showing the configuration of an electric brake device according to an embodiment of the present disclosure.
2 is a circuit diagram showing the configuration of an electric brake device according to an embodiment of the present disclosure.
3 is a circuit diagram showing a controller and a DC power supply according to an embodiment of the present disclosure.
4 is a flowchart illustrating a control method of an electric brake device according to an embodiment of the present disclosure.

Hereinafter, some embodiments of the present disclosure will be described in detail through exemplary drawings. In adding reference numerals to components of each drawing, it should be noted that the same components have the same numerals as much as possible, even if they are displayed on different drawings. In addition, in describing the present disclosure, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present disclosure, the detailed description will be omitted.

In describing the components of the embodiment according to the present disclosure, symbols such as first, second, i), ii), a), and b) may be used. These codes are only for distinguishing the component from other components, and the nature or sequence or order of the corresponding component is not limited by the codes. In the specification, when a part is said to 'include' or 'include' a certain component, it means that it may further include other components, not excluding other components unless explicitly stated otherwise. .

1 is a block diagram showing the configuration of an electric brake device 100 according to an embodiment of the present disclosure.

Referring to FIG. 1, an electro-mechanical brake 100 according to an embodiment of the present disclosure includes a DC power source 120, a control unit 130, and a motor 140. , including all or part of a voltage sensor (not shown) and a current sensor (not shown).

A pedal stroke sensor 170 for detecting a stroke distance of the pedal is connected to the brake pedal 110 . When the driver presses the brake pedal 110, the pedal stroke sensor 170 detects the driver's pedal depression amount. The detected pedal depression amount is transmitted to the control unit 130 . The control unit 130 controls the rotational force of the motor 140 so that the electric brake device 100 generates a required braking pressure. However, embodiments of the present disclosure do not necessarily require a driver's pedal stroke. In the case of an autonomous vehicle, it may be a value calculated not based on a driver's pedal stroke.

)을 갖는다.The DC power supply 120 applies DC current to the controller 130. The DC power source 120 has an internal resistance (

) has

2 is a circuit diagram showing the configuration of an electric brake device 100 according to an embodiment of the present disclosure.

Referring to FIG. 2 , the DC power source 120 may be understood as a voltage source whose voltage varies according to internal resistance and charge amount.

The control unit 130 converts the DC current supplied from the DC power source 120 to generate AC current. Referring to FIG. 2 , the controller 130 includes a plurality of power semiconductor switches to supply AC current to the motor 140 . The control unit 130 generates AC current by controlling the connection state of a plurality of power semiconductor switches.

The motor 140 receives AC current from the control unit 130 . The motor 140 generates rotational force corresponding to the required braking force under the control of the controller 130 . The rotational force generated by the motor 140 is converted into a force for translating a piston (not shown) in the master cylinder 150 by a mechanical mechanism such as a gear (not shown) and a cam (not shown). When the piston in the master cylinder 150 translates, hydraulic pressure is formed in the master cylinder 150 . The formed hydraulic pressure is transmitted to each wheel brake 160 . However, the electric brake device 100 according to an embodiment of the present disclosure includes an electric brake device 100 that does not use hydraulic pressure. That is, the electric brake device 100 according to the present disclosure can be understood as a structure and combination of various devices configured to supply braking pressure to a wheel of a vehicle using the driving force of the motor 140 . For example, the electric brake device 100 according to the present disclosure includes an EMB (Electro-Mechanical Brake).

The voltage sensor senses the DC voltage supplied to the controller 130. The current sensor senses the current supplied to the motor 140. A power sensor (not shown) senses the voltage of the DC power supply.

The controller 130 calculates a maximum power value that can be supplied to the motor 140 based on the voltage of the DC power supply 120 . The control unit 130 sets a limit value of the current applied to the motor 140 based on the maximum power value.

)이 전압요구값(

)과 동일하다고 가정할 수 있다.The control unit 130 calculates a required voltage required for the motor 140 to generate rotational force corresponding to the required braking pressure. The process of the controller 130 calculating the required voltage and generating the AC voltage is performed in a very short time. Therefore, the voltage supplied to the motor 140 (

) is the voltage required value (

) can be assumed to be equal to

을 산출한다. 등가저항은 배터리를 포함하고 배터리의 전압을 출력하기 위한 입력단의 저항을 의미한다.The control unit 130 controls the equivalent resistance (based on the voltage of the DC power supply 120, the voltage supplied to the motor 140, the current supplied to the motor 140, and the required voltage).

yields The equivalent resistance includes a battery and means resistance of an input terminal for outputting a voltage of the battery.

The power supplied to the control unit 130 from the DC power source 120 can be expressed as Equation 1.

The power supplied to the motor 140 by the controller 130 is the product of the rotational force of the motor 140 and the rotational speed of the motor 140 . The power supplied to the motor 140 by the control unit 130 may be expressed as a voltage and current equation as shown in Equation 2.

)과 전류(

)는, 3 개의 상(a,b,c)의 변수를 모터(140)의 회전각도(

)에 대한 정보와 합성하여 두 개의 상(d,q)의 변수로 변환한 것이다. 변환식은 수학식 3과 같이 표현될 수 있다.In Equation 2, the voltage (

) and current (

) is the rotation angle of the motor 140 (a, b, c) variables of the three phases (

) and converted into variables of two phases (d, q). The conversion equation can be expressed as Equation 3.

)을 이용하여 모터(140)의 회전력을 제어한다. 모터(140)에 공급되는 전류 및 모터(140)에 인가되는 직류전압에 대한 정보는 각각 전류센서 및 전압센서를 이용하여 입력된다. 모터(140)의 회전각도는 각도센서를 이용해 제동용 모터(140)의 샤프트(shaft)의 회전 각도를 측정함으로써 계측될 수 있다.In the electric brake device 100, the control unit 130 includes information on two or more phases of the three-phase current supplied to the motor 140, and a DC voltage value applied to the motor 140 (

) to control the rotational force of the motor 140. Information on the current supplied to the motor 140 and the DC voltage applied to the motor 140 are input using a current sensor and a voltage sensor, respectively. The rotation angle of the motor 140 may be measured by measuring the rotation angle of the shaft of the braking motor 140 using an angle sensor.

Power loss caused by the operation of the power semiconductor switch has a very small value compared to the power applied to the motor 140 . Therefore, it is assumed that the power supplied to the control unit 130 by the DC power supply 120 and the power supplied to the motor 140 by the control unit 130 are the same. In this way, the DC current received by the control unit 130 from the DC power supply 120 can be calculated from Equations 1 and 2 as in Equation 4.

3 is a circuit diagram showing a controller and a DC power supply according to an embodiment of the present disclosure.

)으로 나타낸다. 수학식 5와 같이, 등가저항(

)은 도선의 저항(

)과 직류전원(120)의 내부저항(

)을 합한 값을 가진다.The resistance of the wire connecting the DC power supply 120 and the control unit 130 is the wire resistance (

). As shown in Equation 5, equivalent resistance (

) is the resistance of the wire (

) and the internal resistance of the DC power supply 120 (

) has a value that is the sum of

)이 증가한다. 직류전류값이 증가하면, 등가저항에 의한 전압강하량(

)이 증가한다. 전압강하량이 증가하면 직류전원(120)이 제어부(130)에 인가하는 직류전압(

)은 감소한다.When the control unit 130 applies current to the motor 140, the DC power supply 120 supplies the control unit 130 with a DC current value (

) increases. When the DC current value increases, the amount of voltage drop due to the equivalent resistance (

) increases. When the voltage drop increases, the DC voltage applied by the DC power source 120 to the control unit 130 (

) decreases.

)보다 높은 전압이 입력되어야 한다. 그런데 직류전원(120)의 전압이 감소하거나, 내부저항이 증가하는 등으로 모터(140)에 전류를 인가할 때에 제어부(130)에 인가되는 전압이 임계전압에 미치지 않을 수 있다. 이에 따라 제어부(130)를 포함한 브레이크 시스템의 제동성능이 저하되거나, 브레이크 시스템이 정지하는 문제가 발생할 수 있다. 본 개시의 전동식 브레이크장치(100)는 모터(140)에 인가하는 전류량을 제어하여 제어부(130)에 항상 임계전압 이상의 전압이 입력되도록 한다.In order for the control unit 130 to operate normally, the control unit 130 has a threshold voltage (

), a higher voltage must be input. However, when current is applied to the motor 140 due to a decrease in voltage of the DC power source 120 or an increase in internal resistance, the voltage applied to the controller 130 may not reach the threshold voltage. Accordingly, braking performance of the brake system including the controller 130 may deteriorate or the brake system may stop. The electric brake device 100 of the present disclosure controls the amount of current applied to the motor 140 so that a voltage equal to or higher than a threshold voltage is always input to the controller 130 .

When the magnitude of the DC current applied to the control unit 130 is 0, the voltage drop due to the equivalent resistance does not occur, so the DC voltage applied to the control unit 130 has the same value as the voltage of the DC power supply 120.

When the magnitude of the DC current is greater than 0, that is, in a state where the DC current flows through the controller 130, a voltage drop occurs due to equivalent resistance. Therefore, the DC voltage input to the controller 130 can be expressed as Equation 6.

By rearranging Equation 6, it can be expressed as Equation 7.

By substituting Equation 4 into Equation 7, the equivalent resistance value can be calculated as shown in Equation 8.

)을 산출한다.The controller 130 determines the maximum power value that can be supplied to the motor 140 based on the equivalent resistance (

) is calculated.

)보다 높은 전압이 입력되어야 한다. 이를 위하여 제어부(130)에 인가되는 전압의 최소치를 설정한다. 본 개시에서 이를 최소전압(

)이라 한다. 최소전압은 임계전압보다 큰 값을 가진다. 제어부(130)에 최소전압보다 큰 전압이 인가될 수 있도록 할 때, 제어부(130)에 인가 가능한 직류전류의 최댓값을 수학식 9와 같이 계산할 수 있다.In order for the control unit 130 to control the brake device, the control unit 130 has a threshold voltage (

), a higher voltage must be input. To this end, the minimum value of the voltage applied to the controller 130 is set. In the present disclosure, this is the minimum voltage (

) is called The minimum voltage has a value greater than the threshold voltage. When a voltage higher than the minimum voltage can be applied to the controller 130, the maximum value of DC current that can be applied to the controller 130 can be calculated as in Equation 9.

)은 수학식 9로부터 수학식 10과 같이 계산할 수 있다.The maximum power that the controller 130 can supply to the motor 140 (

) can be calculated as in Equation 10 from Equation 9.

)이라 한다. 제어부(130)는 최대전력값에 기초하여 모터(140)에 인가하는 전류의 제한값(

)을 설정한다.Here, the maximum power that the control unit 130 can supply to the motor 140 is the maximum power value (

) is called The control unit 130 limits the current applied to the motor 140 based on the maximum power value (

) is set.

)이라고 한다.The control unit 130 compares the magnitude of the maximum power value that can be supplied to the motor 140 and the threshold power value. Here, the amount of minimum power required for the control unit 130 to operate normally is a threshold power value (

) is called

The control unit 130 according to an embodiment of the present disclosure determines the magnitude of the maximum power value and the threshold power value, and determines the limit value of the current applied to the motor 140 according to the magnitude relationship between the maximum power value and the threshold power value. different way to set it up.

The control unit 130 according to an embodiment of the present disclosure sets the maximum value of the current supplied to the motor 140 as the system rated current when the maximum power value is greater than or equal to the threshold power value. The size of the system rated current and the maximum value of the current supplied to the motor can be determined as shown in Equation 11.

When the maximum power value is less than the threshold power value, a preset minimum voltage is applied to the control unit 130 and a limit value is set so that the motor outputs maximum torque.

이라 할 때 최소전압을 제어부(130)에 인가한 경우 출력 가능한 모터 공급전압의 크기는 수학식 12와 같이 계산할 수 있다.When the voltage and current are in the same phase, the motor 140 can generate maximum rotational force. voltage phase

When the minimum voltage is applied to the control unit 130, the size of the motor supply voltage that can be output can be calculated as in Equation 12.

Using Equations 12 and 2, the maximum power value can be expressed as Equation 13.

이라 하면 수학식 14와 같이 정리할 수 있다.The phase of the maximum value of the current command so that the motor 140 can generate the maximum rotational force.

This can be summarized as in Equation 14.

From Equation 14, the maximum current command value can be set as Equation 15.

When the maximum value of the current command is set as described above, the motor 140 may output the maximum torque within a range in which a voltage equal to or higher than the threshold voltage is applied to the control unit 130 .

4 is a block diagram illustrating a control method of an electric brake device 100 according to an embodiment of the present disclosure.

It is determined whether current is being applied to the controller (S110). When current is not applied to the controller, the voltage value of the DC power source is sensed (S120). The voltage sensor detects the voltage supplied to the motor. The current sensor senses the current value supplied to the motor. Based on the detected voltage and current values, the required voltage required for the motor to generate torque corresponding to the required braking pressure is calculated. Equivalent resistance is calculated based on the voltage of the DC power supply, the voltage supplied to the motor, the current supplied to the motor, and the required voltage (S130). Based on the calculated equivalent resistance value, the maximum value of the current that can flow through the controller is calculated (S140). Based on the calculated equivalent resistance value, the maximum value of power that can be supplied to the motor is calculated. For example, after the step S140, the maximum value of power that can be supplied to the motor is calculated (S150). And, based on the maximum power value, a limit value of the current applied to the motor is set. For example, the control method of the electric brake device 100 according to an embodiment of the present disclosure goes through a process of determining whether the maximum power value is equal to or greater than the threshold power value (S160). If the maximum power value is greater than or equal to the threshold power value, the limit value of the current applied to the motor is set by the first calculation method, and if the maximum power value is less than the threshold power value, the limit value of the current applied to the motor is set by the second calculation method do. The first calculation method may be a method of setting the system rated current as the current limit value (S170). The second calculation method may be a process of applying a voltage equal to or higher than a preset minimum voltage setting value to the control unit and setting a current limit value so that the motor outputs maximum torque (S180).

The above description is merely an example of the technical idea of the present embodiment, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present embodiment. Therefore, the present embodiments are not intended to limit the technical idea of the present embodiment, but to explain, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The scope of protection of this embodiment should be construed according to the claims below, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of rights of this embodiment.

120: DC power
130: control unit
140: motor

Claims (8)

DC power source;
a power sensor for sensing the voltage of the DC power supply;
a control unit for receiving and converting DC current from the DC power source to generate AC current; and
Including a motor that receives AC current from the controller,
The control unit,
A maximum power value that can be supplied to the motor is calculated based on the voltage of the DC power supply, and a limit value of current applied to the motor is set based on the maximum power value. According to claim 1,
a voltage sensor for sensing a DC voltage value supplied to the control unit; and
Further comprising a current sensor for sensing a current value supplied to the motor,
The control unit,
Calculate a required voltage required for the motor to generate a rotational force corresponding to the required braking pressure;
Calculating an equivalent resistance based on the voltage of the DC power supply, the DC voltage supplied to the control unit, the current supplied to the motor, and the required voltage;
An electric brake device for calculating a maximum power value that can be supplied to the motor based on the equivalent resistance. According to claim 1,
The control unit,
Determining the magnitude between the maximum power value and a predetermined threshold power value;
Different methods of setting the limit value of the current applied to the motor according to the magnitude relationship between the maximum power value and the threshold power value,
electric brake system. According to claim 3,
The control unit,
When the maximum power value is greater than or equal to the threshold power value, setting the system rated current to the limit value;
When the maximum power value is less than the threshold power value, applying a predetermined minimum voltage to the control unit, and setting the limit value so that the motor outputs maximum torque. determining whether current is being applied to the control unit;
detecting a voltage value of a DC power supply when current is not being applied to the control unit;
Calculating a maximum power value that can be supplied to the motor based on the voltage of the DC power supply; and
An electric brake device control method comprising the step of setting a limit value of the current applied to the motor based on the maximum power value. According to claim 5,
The process of calculating the maximum power value,
detecting a voltage value supplied to the motor;
sensing a current value supplied to the motor;
calculating a required voltage required to cause the motor to generate rotational force corresponding to the required braking pressure;
calculating an equivalent resistance based on the voltage of the DC power supply, the voltage supplied to the motor, the current supplied to the motor, and the required voltage;
Calculating a maximum power value that can be supplied to the motor based on the equivalent resistance; and
Setting a limit value of current applied to the motor based on the maximum power value
Electric brake device control method comprising a. According to claim 5,
The process of setting the limit value of the current applied to the motor,
determining whether the maximum power value is greater than or equal to a predetermined threshold power value;
setting a limit value of current applied to the motor by a first calculation method when the maximum power value is greater than or equal to the threshold power value; and
Setting a limit value of current applied to the motor by a second calculation method when the maximum power value is less than the threshold power value
Electric brake device control method comprising a. According to claim 5,
The process of setting the limit value of the current applied to the motor,
determining whether the maximum power value is greater than or equal to a predetermined threshold power value; and
setting a system rated current to the limit value when the maximum power value is greater than or equal to the threshold power value; and
When the maximum power value is less than the threshold power value, applying a predetermined minimum voltage value to the control unit and setting the limit value so that the motor outputs maximum torque
Electric brake device control method comprising a.

Images