KR102047877B1 - Apparatus and method for controlling PWM signal - Google Patents

Abstract

The present invention relates to a PWM signal control device, and more particularly, to a PWM signal control device for controlling the duty ratio of the PWM signal to output a normal PWM signal after the block is released, even if the PWM signal is temporarily blocked due to noise. It is about. PWM signal control device according to an embodiment of the present invention is a motor comprising a stator coiled and a rotor disposed in the stator is rotated by a magnetic field generated in the coil, the alternating current to the coil in accordance with the PWM signal Providing an inverter, a microcomputer for controlling the duty ratio of the PWM signal using the motor driving information of the motor and the output current of the inverter, and providing the PWM signal to the inverter, and whether the output current of the inverter is an overcurrent And a gate driver for generating a fault signal and blocking the PWM signal for a cutoff time, wherein the microcomputer outputs the output current of the inverter detected in the sampling period before the fault signal is generated when the fault signal is generated. The value is stored in a memory, and the motor drive information and the output current value stored in the memory are stored. And characterized by controlling the duty ratio of the PWM signal provided after the off time the inverter.

Description

Apparatus and method for controlling PWM signal

The present invention relates to a PWM signal control device and method, and more particularly, even if the PWM signal is temporarily blocked due to noise, PWM signal control to control the duty ratio of the PWM signal to output a normal PWM signal after the block is released An apparatus and method are provided.

Small motors capable of precise control are largely classified into AC motors, DC motors, Brushless DC motors (BLDC), and reluctance motors.

Such small motors are used for AV (Audio-Visual) devices, computers, home appliances, industrial, and the like. In particular, the home appliance field is one of the largest markets for small motors. Recently, home appliances are gradually being advanced, and accordingly, there is an increasing demand for high-performance motors embedded in home appliances.

In particular, the brushless DC motor is a motor without a brush and a commutator, it is excellent in speed control and torque control without mechanical friction. In addition, the brushless DC motor is easy to miniaturize, has a strong durability and a very long life has been used in many home appliances.

Recently, there is an increasing demand for a household cleaner having a small size but strong suction power, and thus the rotation speed of the brushless DC motor included in the cleaner is gradually increasing.

The brushless DC motor is driven by an inverter operating according to a PWM signal. When the motor rotates at a high speed, noise is generated in a device (eg, an inverter or a gate driver) driving the motor.

On the other hand, the motor is feedback-controlled according to the output current value of the inverter, if the PWM signal is temporarily cut off due to the noise described above, after the PWM signal is cut off the output current value of the inverter becomes a garbage value (garbage value) Normal feedback control for is not performed.

In other words, if the PWM signal is temporarily blocked due to noise generated when the motor rotates at a high speed, feedback control based on an invalid value is performed. Accordingly, the PWM signal is divergently controlled to cause a system failure, or the PWM signal is zero. There is a problem that the convergence control to stop the driving of the motor.

Accordingly, there is a demand for a method of stably controlling the motor even if the PWM signal is temporarily blocked due to noise.

An object of the present invention is to provide a PWM signal control device and method for controlling the duty ratio of the PWM signal to output a normal PWM signal after the block is released even if the PWM signal is temporarily blocked due to noise.

The present invention includes a gate driver that generates a fault signal and blocks a PWM signal provided to the inverter during the interruption time when the output current of the inverter is an overcurrent. In addition, the present invention further includes a microcomputer for controlling the duty ratio of the PWM signal provided to the inverter after the interruption time by using the output current value of the inverter detected in the sampling period before the generation of the fault signal when the fault signal is generated. . Accordingly, the present invention can control the duty ratio of the PWM signal to output the normal PWM signal after the blocking is released even if the PWM signal is temporarily blocked due to noise.

According to the present invention, even if the PWM signal is temporarily blocked due to noise, the duty ratio of the PWM signal can be controlled to output a normal PWM signal after the blocking is released. Accordingly, the present invention can prevent the PWM signal due to noise or the driving stop of the motor, and can stably control the motor.

1 and 2 are block diagrams illustrating a PWM signal control apparatus according to an embodiment of the present invention.
3 is a block diagram illustrating a control configuration of a microcomputer according to an exemplary embodiment of the present invention.
4 is a diagram illustrating output pulses of a microcomputer and a gate driver, an output current of an inverter, and a pulse of a failure signal.
5 is a diagram illustrating pulses of a PWM signal and a failure signal applied to an inverter.
6 is a flowchart illustrating a PWM signal control method according to an embodiment of the present invention.
7 is a flowchart illustrating an operation process of a microcomputer after a failure signal is generated.
8 is a flowchart showing a process of an interrupt service routine called by micom.

The above objects, features, and advantages will be described in detail with reference to the accompanying drawings, whereby those skilled in the art to which the present invention pertains may easily implement the technical idea of the present invention. In describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

1 and 2 are block diagrams illustrating a PWM signal control apparatus according to an embodiment of the present invention. Hereinafter, a PWM signal control device and each component constituting the same will be described in detail with reference to FIGS. 1 and 2.

1 and 2, the PWM signal control device 100 according to an embodiment of the present invention includes a motor M, 110, an inverter 120, a gate driver 130, and a microcomputer MICOM. 140). The PWM signal control device 100 shown in FIGS. 1 and 2 is according to one embodiment, and its components are not limited to the embodiment shown in FIGS. 1 and 2, and some components may be It can be added, changed or deleted.

The motor 110 may include a stator (not shown) in which coils are wound, and a rotor (not shown) disposed in the stator and rotating by a magnetic field generated in the coil.

The motor 110 may include an induction motor, a brushless DC motor (BLDC), and a reluctance motor. However, the motor 110 described below is preferably a brushless DC motor capable of miniaturization and high noise and high reliability.

In addition, the motor 110 described below is assumed to be a three-phase motor having a stator wound with a three-phase coil and operated by receiving a three-phase alternating current.

The inverter 120 may provide an alternating current to the coil constituting the motor 110 according to a pulse width modulation (PWM) signal. As described above, when the motor 110 is a three-phase motor, the inverter 120 may provide three-phase (U, V, W) alternating current to the coil.

When a three-phase alternating current is provided to the coil of the motor 110, the permanent magnet included in the rotor may rotate according to the magnetic field generated by the three-phase coil. The motor 110 may be driven by the rotational force of the rotor.

The inverter 120 may operate according to a PWM signal provided from the gate driver 130, which will be described later, and convert the DC voltage V _DC to output an AC current. To this end, the inverter 120 may include a plurality of power switching elements that perform a switching operation according to the PWM signal, and the power switching element may be, for example, an Insulated Gate Bipolar Transistor (IGBT).

The power switching element included in the inverter 120 performs an on and off operation according to a PWM signal for each phase, thereby converting a DC voltage V _DC into an alternating current I _a , I _b , I _c and a motor. 110 may be provided.

As shown in FIG. 2, the inverter 120 may include two switching elements corresponding to each phase to output a three-phase current. More specifically, in order to output the U phase AC current I _a , the inverter 120 may include two switches S1 and S1 ′ corresponding to the U phase. In addition, to output the V phase AC current I _b , the inverter 120 may include two switches S2 and S2 ′ corresponding to the V phase. Finally, to output the W phase AC current I _c , the inverter 120 may include two switches S3 and S3 ′ corresponding to the W phase.

Two switches corresponding to each phase may be composed of upper arm switches S1, S2, and S3 and lower arm switches S1 ', S2', and S3 '. The upper arm switches S1, S2, S3 and the lower arm switches S1 ', S2', and S3 'are the upper arm PWM signals HO 1, HO 2, and HO 3 and the lower arm PWM signals applied by the gate driver 130, which will be described later. They can be turned on or off according to (LO 1, LO 2, LO 3) respectively.

The microcomputer 140 may control the duty ratio of the PWM signal provided to the inverter 120 by using the motor driving information of the motor 110 and the output current of the inverter 120. Herein, the motor driving information is information indicating the driving state of the motor 110, and the electric angle position of the rotor constituting the motor 110, the speed of the rotor, the target speed value of the motor 110, and the inverter 120 It may include at least one of the output current value and the output voltage value of the inverter 120.

Here, the target speed value is a value input from a user or an external device and may be a target value for the rotation speed of the motor 110.

The duty ratio of each pulse included in the PWM signal may be changed according to the amount of current to be output. More specifically, the larger the duty ratio, the larger the output of the inverter 120, the smaller the duty ratio, the smaller the output of the inverter 120 may be.

Accordingly, the microcomputer 140 may determine the duty ratio of the PWM signal for following the target speed value in consideration of the motor driving information at the control time and the output current of the inverter 120.

3 is a block diagram illustrating a control configuration of a microcomputer according to an exemplary embodiment of the present invention. Hereinafter, the control operation of each component constituting the microcomputer will be described in detail with reference to FIG. 3.

Referring to FIG. 3, the microcomputer 140 includes a position estimator 141, a speed calculator 142, a command value generator 143 and 144, a duty controller 145, and a three-phase and two-phase axis converter 146. ) May be included. The microcomputer 140 shown in FIG. 3 is according to an embodiment including the logical components described above, and the components are not limited to the embodiment shown in FIG. 3, and some components may be added as necessary. , Can be changed or deleted.

Meanwhile, the AC current I _abc and the AC voltage V _abc illustrated in FIG. 3 are three-phase AC currents I _a , I _b , I _c and three-phase AC voltages V _a , V _b , V _{c, respectively.} ) As a parameter. Accordingly, the alternating current I _abc and the alternating voltage V _abc illustrated in FIG. 3 may represent current and voltage of each phase output from the inverter 120 to the motor 110.

)를 추정할 수 있다. 보다 구체적으로, 먼저 위치 추정부(141)는 인버터(120)의 출력전류 및 출력전압 중 적어도 하나에 기초하여 회전자의 위치를 추정하고, 그 다음 추정된 회전자의 위치에 기초하여 전기각 위치(

)를 연산할 수 있다.The position estimator 141 is configured to measure the electric angle of the rotor based on at least one of the output current and the output voltage of the inverter 120.

) Can be estimated. More specifically, first, the position estimator 141 estimates the position of the rotor based on at least one of the output current and the output voltage of the inverter 120, and then the electric angle position based on the estimated position of the rotor. (

) Can be calculated.

)를 측정하는 위치센서(예를 들어, 홀센서)가 포함되는 경우, 위치 추정부(141)는 생략될 수 있다.In contrast, in the present invention the electric angle position (

When a position sensor (for example, a hall sensor) measuring) is included, the position estimator 141 may be omitted.

) 및 인버터(120)의 출력전압에 기초하여 회전자의 속도(

)를 산출할 수 있다. 보다 구체적으로, 속도 산출부(142)는 위치 추정부(141)에서 추정된 회전자의 위치를 시간(예를 들어, PWM 주기 또는 샘플링주기)으로 나누어 회전자의 속도(

)를 산출할 수 있다.The speed calculator 142 may calculate the electric angle position estimated by the position estimator 141.

) And the speed of the rotor based on the output voltage of the inverter 120

) Can be calculated. More specifically, the speed calculator 142 divides the rotor position estimated by the position estimator 141 by time (for example, a PWM cycle or a sampling cycle) to determine the speed of the rotor (

) Can be calculated.

The command value generator may be configured of a current command value generator 143 and a voltage command value generator 144, which will be described below.

) 및 목표 속도값(

)에 기초하여 전류 지령치(

)를 생성할 수 있다.The current command value generation unit 143 is a speed of the rotor calculated by the speed calculation unit 142 (

) And target speed value (

Based on the current setpoint (

) Can be created.

) 및 목표 속도값(

)에 기초하여 속도 지령치를 산출하고, 산출된 속도 지령치에 기초하여 전류 지령치(

)를 생성할 수 있다.More specifically, the current command value generator 143 is a speed of the rotor (

) And target speed value (

Is calculated on the basis of the calculated speed command value and the current command value (

) Can be created.

)를 생성하기 위하여, PI 제어(Proportional Integral Control)를 수행할 수 있다. 보다 구체적으로, 전류 지령치 생성부(143)는 회전자의 속도(

)와 목표 속도값(

)의 차이인 속도 지령치를 산출하고, 속도 지령치에 기초하여 PI 제어를 수행함으로써 전류 지령치(

)를 생성할 수 있다.The current command value generating unit 143 is the current command value (

In order to generate the I / O control, PI (Proportional Integral Control) can be performed. More specifically, the current command value generator 143 is a speed of the rotor (

) And target speed value (

By calculating the speed setpoint which is a difference between the two and the PI command control based on the speed setpoint, the current setpoint (

) Can be created.

)가 허용 범위를 초과하지 않도록 제한하는 리미터(미도시)를 더 구비할 수도 있다.Meanwhile, the current command value generator 143 generates the generated current command value (

) May be further provided with a limiter (not shown) to limit not to exceed the allowable range.

) 및 인버터(120)의 출력전류(

)에 기초하여 전압 지령치(

)를 생성할 수 있다. 여기서 전압 지령치(

) 생성의 기초가 되는 출력전류(

)는 전술한 3상 출력전류(I_a, I_b, I_c)를 축변환하여 생성될 수 있다.The voltage command value generator 144 generates the generated current command value (

) And the output current of the inverter 120 (

Voltage setpoint based on

) Can be created. Where voltage setpoint (

Output current on which

) May be generated by axis-converting the above-described three-phase output current (I _a , I _b , I _c ).

)로 축변환할 수 있다. 또한, 3상/2상 축변환부(146)는 정지 좌표계의 2상 전류(

)를 회전 좌표계의 2상 전류(

)로 축변환할 수 있다.More specifically, the three-phase / two-phase axis converter 146 shown in FIG. 3 receives the three-phase output currents I _a , I _b , I _c of the inverter 120 to receive the two-phase current of the stationary coordinate system (

Can be converted to axis. In addition, the three-phase / two-phase axis conversion unit 146 is a two-phase current (

) Is the two-phase current (

Can be converted to axis.

)와 전류 지령치 생성부(143)에서 생성된 전류 지령치(

)에 기초하여 전압 지령치(

)를 생성할 수 있다.The voltage command value generator 144 is a q-axis, d-axis current (

) And the current command value generated by the current command value generator 143 (

Voltage setpoint based on

) Can be created.

)를 생성하기 위하여 PI 제어를 수행할 수 있다.The voltage command value generator 144 is configured as described above.

PI control can be performed to generate

)와 q축 전류 지령치(

) 의 차이에 기초하여 PI 제어를 수행함으로써 q축에 대한 목표 지령치(

)를 생성할 수 있다.More specifically, the voltage command value generation unit 144 is a q-axis current (

) And q-axis current setpoint (

By performing PI control based on the difference of

) Can be created.

)와 d축 전류 지령치(

)의 차이에 기초하여 PI 제어를 수행함으로써 d축에 대한 목표 지령치(

)를 생성할 수 있다.In addition, the voltage command value generation unit 144 is a d-axis current (

) And d-axis current setpoint (

Target control value for the d-axis by performing PI control based on the difference of

) Can be created.

)가 허용 범위를 초과하지 않도록 제한하는 리미터(미도시)를 더 구비할 수도 있다.On the other hand, the voltage command value generator 144 is a voltage command value for the q-axis and d-axis (

) May be further provided with a limiter (not shown) to limit not to exceed the allowable range.

)는 듀티 제어부(145)에 입력될 수 있다. 이에 따라, 듀티 제어부(145)는 인버터(120)에 제공되는 PWM 신호의 듀티비를 전압 지령치(

)에 대응하는 듀티비로 제어할 수 있다.The above voltage setpoint (

) May be input to the duty controller 145. Accordingly, the duty controller 145 sets the duty ratio of the PWM signal provided to the inverter 120 to the voltage command value (

Can be controlled by the duty ratio corresponding to

)는 목표 속도값(

)을 추종할 수 있다. 다시 말해, 회전자의 속도(

)는 인버터(120)의 출력전류의 크기에 비례할 수 있고 전술한 바와 같이 출력전류의 크기는 PWM 신호에 포함된 펄스의 폭에 비례할 수 있다.Thus, the speed of the rotor (

) Is your target speed value (

) Can be followed. In other words, the speed of the rotor (

) May be proportional to the magnitude of the output current of the inverter 120, and as described above, the magnitude of the output current may be proportional to the width of the pulse included in the PWM signal.

)가 목표 속도값(

)보다 크면 PWM 신호의 듀티비를 감소시키고, 현재 회전자의 속도(

)가 목표 속도값(

)보다 작으면 PWM 신호의 듀티비를 증가시킬 수 있다.The duty controller 145 controls the speed of the current rotor (

) Is your target speed value (

Greater than) reduces the duty ratio of the PWM signal and

) Is your target speed value (

Less than) may increase the duty ratio of the PWM signal.

The microcomputer 140 may perform the above-described control operation every sampling period, that is, whenever the output current of the inverter 120 is measured. Accordingly, the motor driving information and the output current of the inverter 120 used for the control operation of the microcomputer 140 may be information on the current driving state of the motor 110 and the current currently output from the inverter 120.

The duty ratio control of the microcomputer 140 may be performed by providing a control signal including the duty ratio information to the gate driver 130 to be described later. Referring back to FIG. 2, the microcomputer 140 may provide the gate arm 130 with the phase arm control signals HIN 1 to HIN 3 and the arm arm control signals LIN 1 to LIN 3 for controlling the duty ratio of the PWM signal. Can be.

Each control signal may be output in the form of a pulse of a square wave, and the duty ratio of the control signal may be the same as the duty ratio of the PWM signal to be controlled. In other words, the duty ratio of the PWM signal generated according to the control signal may be equal to the duty ratio of the corresponding control signal.

The gate driver 130 may provide a PWM signal to the inverter 120. More specifically, the gate driver 130 receives the control signals HIN 1 to HIN 3 and LIN 1 to LIN 3 from the microcomputer 140, and generates a PWM signal having the same duty ratio as the duty ratio of the control signal. It may be provided to the inverter 120.

However, the magnitude of the PWM signal generated by the gate driver 130 may be determined according to an operating voltage applied to the gate terminal of the switching element constituting the inverter 120. In other words, the gate driver 130 may receive a control signal having a specific duty ratio and provide the inverter 120 with a PWM signal having a specific duty ratio and a size set to an operating voltage of the switching device.

The gate driver 130 may detect the output current of the inverter 120 to determine whether the detected output current is an overcurrent. The gate driver 130 may detect an output current for each phase of the inverter 120 to determine whether the detected output current of each phase is an overcurrent.

In addition, the gate driver 130 may detect the synthesized current of the three-phase output current of the inverter 120 to determine whether the detected synthesized current is an overcurrent. In this case, as shown in FIG. 2, the output current of the inverter 120 may be detected through one shunt resistor.

The gate driver 130 may determine that an overcurrent has occurred in the inverter 120 when the detected output current exceeds a preset value for a preset time.

More specifically, the composite current of the inverter 120 is the I _TRIP of the gate driver 130. It may be provided as a terminal, and the gate driver 130 may determine whether the magnitude of the synthesized current exceeds a preset value for a preset time.

In addition, the gate driver 130 is I _TRIP. By separating the combined current provided to the terminal into a three-phase alternating current, it is possible to determine whether the magnitude of each separated current exceeds a preset value for a preset time.

When the magnitude of the detected current exceeds a preset value for a preset time, the gate driver 130 may generate a fault signal FO and cut off the PWM signal provided to the inverter 120 for a cutoff time.

In other words, when it is determined that an overcurrent has occurred, the fault signal is provided to the microcomputer 140 through the FAULT terminal shown in FIG. 2, and the PWM signals HO 1 to HO 3 and LO 1 to output from the gate driver 130 are provided. LO 3) may be blocked.

Here, a preset time for overcurrent determination and a cutoff time at which the PWM signal and the PWM signal are blocked may be determined according to the specifications of the gate driver 130. In addition, the gate driver 130 may further include an over current protection (OCP) module to perform the above-described comparison operation and the blocking operation.

When the fault signal is generated in the gate driver 130, the microcomputer 140 may store the output current value of the inverter 120 detected in the sampling period before the generation of the fault signal in the memory.

The output current of the inverter 120 may be detected according to a sampling period, and when the microcomputer 140 receives a failure signal from the gate driver 130, the inverter 120 detected in the sampling period before the time when the failure signal is generated. The output current value of can be stored in the memory.

More specifically, the microcomputer 140 may store the output current value of the inverter 120 detected in the sampling cycle immediately before the failure signal is generated among the sampling cycles before the failure signal is generated in the memory.

Since the output current value detected in the sampling period immediately before the fault signal is generated is not determined to be an overcurrent, the microcomputer 140 stores the output current value of the inverter 120 detected immediately before the overcurrent occurs in the memory. Can be.

The microcomputer 140 may control the duty ratio of the PWM signal provided to the inverter 120 after the cutoff time by using the motor driving information and the output current value stored in the memory.

)를 추정할 수 있다.More specifically, referring to FIG. 3, the position estimator 141 may determine the electric angle of the rotor based on at least one of the output current and the output voltage of the inverter 120 after the failure signal is generated.

) Can be estimated.

) 및 인버터(120)의 출력전압 중 적어도 하나에 기초하여 회전자의 속도(

)를 산출할 수 있다. 이 때, 산출된 회전자의 속도(

)는 PWM 신호의 출력 차단으로 인해 과전류가 발생하기 이전보다 감소할 수 있다.The speed calculator 142 calculates the estimated electric angle position (

) And the speed of the rotor based on at least one of the output voltages of the inverter 120 (

) Can be calculated. At this time, the calculated speed of the rotor (

) Can be reduced from before the overcurrent occurs due to the output blocking of the PWM signal.

) 및 모터(110)의 목표 속도값(

)에 기초하여 전류 지령치(

)를 생성하고, 생성된 전류 지령치(

) 및 메모리에 저장된 출력전류 값에 기초하여 전압 지령치(

)를 생성할 수 있다.The setpoint generator generates the calculated speed of the rotor (

) And the target speed value of the motor 110 (

Based on the current setpoint (

) And the generated current setpoint (

) And based on the output current value stored in memory

) Can be created.

In other words, the output current of the inverter 120 used by the position estimator 141 and the speed calculator 142 described above is the output current detected at the present time, while the output of the inverter 120 used by the command value generator is used. The current may be an output current value detected in the sampling period immediately before the failure signal is generated.

)는 게이트 드라이버(130)의 출력 차단으로 인해 과전류가 발생하기 이전보다 감소할 수 있고, 이에 따라 목표 속도값과 회전자의 속도(

)의 차이는 커질 수 있다. 이에 따라, 지령치 생성부에서 생성되는 전류 지령치(

)는 과전류가 발생하기 이전보다 커질 수 있다.As mentioned above, the speed of the rotor (

) May be reduced than before the overcurrent occurs due to the output blocking of the gate driver 130, and thus the target speed value and the speed of the rotor (

) Can be large. Accordingly, the current command value generated in the command value generator (

) May be larger than before overcurrent occurs.

)와 메모리에 저장된 출력전류 값에 기초하여 전압 지령치(

)를 생성할 수 있다. 전류 지령치(

)의 크기 상승으로 인해 전류 지령치(

)와 메모리에 저장된 출력전류 값의 차이는 커질 수 있고, 이에 따라, 지령치 생성부에서 생성되는 전압 지령치(

) 또한 과전류가 발생하기 이전보다 커질 수 있다.The setpoint generator generates the generated current setpoint (

) And based on the output current value stored in memory

) Can be created. Current setpoint (

Current setpoint (

) And the difference between the output current value stored in the memory can be large, and accordingly, the voltage command value (

) It can also be larger than before overcurrent occurs.

)가 생성되면, 듀티 제어부(145)는 생성된 전압 지령치(

)에 따라 차단시간 이후 인버터(120)에 제공되는 PWM 신호의 듀티비를 제어할 수 있다. 이에 따라, 차단시간 이후 인버터(120)에 제공되는 PWM 신호의 듀티비는 과전류가 발생하기 이전 펄스의 듀티비보다 클 수 있다.Voltage setpoint (

Is generated, the duty controller 145 generates the generated voltage command value (

), The duty ratio of the PWM signal provided to the inverter 120 after the cutoff time may be controlled. Accordingly, the duty ratio of the PWM signal provided to the inverter 120 after the cutoff time may be greater than the duty ratio of the pulse before overcurrent occurs.

On the other hand, when the fault signal is generated, the microcomputer 140 further stores the motor drive information at the time of generating the fault signal in the memory, and stores the duty ratio of the PWM signal provided to the inverter 120 after the break time in the memory. It can be controlled by the duty ratio according to the output current value.

In this case, the motor drive information stored by the microcomputer 140 may include at least one of an electric angle position of the rotor, a speed of the rotor, and a target speed value when the failure signal is generated.

The microcomputer 140 does not need to calculate the electric angle position of the rotor and the speed of the rotor by using the output current or the output voltage value currently output from the inverter 120. And a current command value and a voltage command value using the target speed value.

For example, when the motor 110 rotates at a high speed, a noise signal may be generated in the inverter 120 and the gate driver 130, and thus an output current value provided to the I _TRIP terminal of the gate driver 130. An error may occur.

In this case, even if the output current of the inverter 120 is not an overcurrent, the gate driver 130 may determine that an overcurrent has occurred in the inverter 120. Accordingly, in addition to the output current of the inverter 120, parameters measured by the inverter 120 may be normal.

Accordingly, when the microcomputer 140 receives a failure signal from the gate driver 130, the microcomputer 140 may output motor driving information including an electric angle position of the rotor, a speed of the rotor, a target speed value, and the like at the time when the failure signal is generated. Can be stored in memory.

The microcomputer 140 may generate a current command value using the electric angle position of the stored rotor, the speed and the target speed value of the rotor, and generate a voltage command value based on the generated current command value and the output current value stored in the memory. have.

In other words, the microcomputer 140 may generate a voltage command value based on the current command value calculated at the time of generating the fault signal and the output current value detected in the sampling period immediately before the time of generating the fault signal. The microcomputer 140 may control the duty ratio of the PWM signal output from the gate driver 130 after the blocking time according to the generated voltage command value.

That is, the microcomputer 140 outputs a PWM signal to output a normal PWM signal after the blocking time has elapsed using the output current value immediately before the gate driver 130 determines the overcurrent and the motor driving information of the instant determined as the overcurrent. The duty ratio of can be controlled.

The aforementioned duty ratio control operation of the microcomputer 140 may be performed by a specific interrupt service routine (ISR) within the microcomputer 140 system. Accordingly, the CPU of the microcomputer 140 may call the interrupt service routine when a failure signal is provided from the gate driver 130, and the called interrupt service routine may perform the duty ratio control operation described above.

4 is a diagram illustrating output pulses of a microcomputer and a gate driver, an output current of a inverter and a pulse of a failure signal, and FIG. 5 is a diagram illustrating a pulse of a PWM signal and a failure signal applied to an inverter. Herein, the output pulse of the microcomputer 140 may be the above-described control signal, and the output pulse of the gate driver 130 may be a PWM signal.

Hereinafter, the control signal, the PWM signal, and the failure signal generated before and after the interruption time will be described in detail with reference to FIGS. 4 and 5.

Referring to FIG. 4, the output voltage of the inverter 120 detected at the I _TRIP terminal of the gate driver 130 may be a composite current of the three-phase current output from the inverter 120. The synthesis current of the three-phase current shown in FIG. 4 is shown for convenience of description and may be output in an arbitrary waveform.

The gate driver 130 may determine whether the magnitude of the output current of the inverter 120 detected at the I _TRIP terminal exceeds a preset value I _limit for a preset time T. If the magnitude of the output current exceeds the preset value (I _limit ) for a preset time T, the gate driver 130 generates a fault signal FO and the PWM signals HO and LO provided to the inverter 120. ) Can be blocked.

Accordingly, the PWM signals HO and LO according to the control signals HIN and LIN may not be output in the blocking section shown in FIG. 4.

During the interruption time when the PWM signal is interrupted, the microcomputer 140 calls the interrupt service routine (ISR), and the output current value of the inverter 120 and the current motor of the motor 110 detected in the sampling cycle immediately before the failure signal is generated. The duty ratio according to the driving information may be determined.

Thereafter, when the blocking time is elapsed, the microcomputer 140 may provide the control signals HIN and LIN having the determined duty ratio to the gate driver 130, and the gate driver 130 may provide the provided control signals HIN and LIN. Based on the PWM output (HO, LO) can be provided to the inverter 120.

Referring to FIG. 5, the PWM signal for the U phase may be output in the form of increasing and decreasing pulses and may have a predetermined period T. When the failure signal FO occurs immediately after the a pulse is output, the gate driver 130 may block the a pulse.

During the time a pulse is interrupted, the microcomputer 140 detects an output current value of the inverter 120 according to a pulse immediately before the pulse a (a left pulse of a pulse), and detects the output current value and the current motor driving information. Based on the duty cycle of the b pulse to be output after the cutoff time can be determined.

As described above, the rotation speed of the motor 110 may decrease during the time a pulse is blocked, so that the duty ratio of the b pulse may be greater than the duty ratio of the a pulse. In other words, the b pulses output after the cutoff time may be greater than the duty ratio of the a pulses that were to be output at the time when the failure signal was generated.

6 is a flowchart illustrating a PWM signal control method according to an embodiment of the present invention. Hereinafter, a PWM signal control method of a control unit providing a PWM signal to an inverter driving a motor will be described in detail with reference to FIG. 6.

In this case, the control unit may include a microcomputer 140 and a gate driver 130 illustrated in FIG. 1. Accordingly, description of each component constituting the control unit will be omitted.

Referring to FIG. 6, the control unit may determine whether the output current of the inverter is an overcurrent (S110).

More specifically, the control unit may detect the output current of the inverter and determine whether the detected output current exceeds a preset value for a preset time. As a result of the determination, if the detected output current exceeds a preset value for a preset time, the output current may be determined as an overcurrent.

Subsequently, when the output current of the inverter is determined to be an overcurrent, the control unit may generate a fault signal and block the PWM signal provided to the inverter during the cutoff time (S120).

Subsequently, when the fault signal is generated, the control unit may store the motor drive information of the motor and the output current value detected in the sampling period before the time of generating the fault signal in the memory (S130). Since the motor drive information has been described above, a detailed description thereof will be omitted.

Subsequently, the control unit determines the duty ratio of the PWM signal using the motor driving information and the output current value stored in the memory (S140), and when the cutoff time is reached, the control unit may provide the inverter with a PWM signal having the duty ratio determined previously. (S150).

The above-described steps S110, S120, and S150 may be performed by the gate driver illustrated in FIG. 1. Meanwhile, steps S130 and S140 may be performed by the microcomputer shown in FIG. 1.

7 is a flowchart illustrating an operation process of a microcomputer after a fault signal is generated, and FIG. 8 is a flowchart illustrating a process of an interrupt service routine called by the microcomputer. Hereinafter, a process of determining the duty ratio of the PWM signal by the microcomputer among the components of the control unit will be described in detail with reference to FIGS. 7 and 8.

Referring to FIG. 7, the microcomputer may receive a failure signal generated by the gate driver (S210).

Subsequently, the microcomputer may call an interrupt service routine (ISR) in response to the received failure signal (S220).

Subsequently, the microcomputer may determine the duty ratio of the PWM signal to be provided to the inverter after the interruption time through the called interrupt service routine ISR (S230).

More specifically, referring to FIG. 8, an interrupt service routine (hereinafter, referred to as an ISR) loads motor driving information and an output current value stored in a memory (S221), and based on at least one of an output current and an output voltage of an inverter, the rotor is loaded. The electric angle position of may be estimated (S222).

Subsequently, the ISR may calculate the speed of the rotor based on at least one of the estimated electric angle position and the output voltage of the inverter (S223).

Subsequently, the ISR may generate a current command value based on the calculated rotor speed and the target speed value of the motor (S224), and generate a voltage command value based on the generated current command value and the output current value stored in the memory ( S225). In addition, the ISR may determine the duty ratio of the PWM signal to be provided to the inverter after the cutoff time has elapsed based on the generated voltage command value.

The output voltage and output current values of the inverter used in steps S222 to S224 may be values included in current motor driving information of the motor 110. Meanwhile, the output current value of the inverter used in step S225 may be an output current value stored in the memory, and may be an output current value detected in a sampling period before the generation of the fault signal.

Referring back to FIG. 7, the microcomputer may provide the duty ratio information determined by the ISR to the gate driver (Drive IC) (S240). Accordingly, the gate driver may provide the inverter with a PWM signal having a duty ratio determined by the ISR.

As described above, the present invention controls the duty ratio of the PWM signal to output a normal PWM signal after the blocking is released, even if the PWM signal is temporarily blocked due to noise, thereby releasing the PWM signal caused by the noise or stopping the driving of the motor. Can be prevented and thus the motor can be stably controlled.

The present invention as described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by.

110: motor 120: inverter
130: gate driver 140: micom

Claims (10)

A motor including a stator having a coil wound thereon and a rotor disposed within the stator and rotating by a magnetic field generated in the coil;
An inverter providing an alternating current to the coil in accordance with a PWM signal;
A microcomputer controlling the duty ratio of the PWM signal by using motor driving information of the motor and an output current of the inverter; And
A gate driver configured to provide the PWM signal to the inverter, generate a fault signal according to whether the output current of the inverter is an overcurrent, and block the PWM signal for a cutoff time;
The microcomputer, when the fault signal is generated, stores the output current value of the inverter detected in the sampling period before the generation time of the fault signal in a memory, and stores current motor driving information of the motor and the output current stored in the memory. Controlling the duty ratio of the PWM signal provided to the inverter after the cutoff time using a value
PWM signal control device.
The method of claim 1,
The gate driver
And detecting the output current of the inverter and generating the fault signal to the microcomputer if the detected output current exceeds a preset value for a preset time.
The method of claim 1,
The microcomputer
When the fault signal is generated, the motor drive information at the time of generating the fault signal is further stored in the memory, and the duty ratio of the PWM signal provided to the inverter after the interruption time is stored in the memory. PWM signal control device to control the duty ratio according to the current value.
The method of claim 3,
The motor drive information is
And at least one of an electric angle position of the rotor, a speed of the rotor, a target speed value of the motor, an output current value of the inverter, and an output voltage value of the inverter.
The method of claim 1,
The microcomputer
A position estimating unit estimating an electric angle position of the rotor based on at least one of an output current and an output voltage of the inverter after the failure signal is generated;
A speed calculator configured to calculate a speed of the rotor based on at least one of the estimated electric angle position and an output voltage of the inverter;
A command value generator for generating a current command value based on the calculated speed and a target speed value of the motor and generating a voltage command value based on the generated current command value and the output current value stored in the memory; And
And a duty controller configured to control a duty ratio of the PWM signal provided to the inverter after the cutoff time according to the generated voltage command value.
The method of claim 1,
The microcomputer
And an interrupt service routine (ISR) for controlling the duty ratio of the PWM signal when the fault signal is provided from the gate driver.
In the PWM signal control method of the control unit for providing a PWM signal to the inverter for driving the motor,
Determining whether the output current of the inverter is an overcurrent;
Generating a fault signal and interrupting the PWM signal provided to the inverter during the interruption time when it is determined that the output current of the inverter is an overcurrent;
Storing the current motor driving information of the motor and an output current value detected in a sampling period before the generation time of the failure signal when the failure signal is generated; And
And controlling the duty ratio of the PWM signal provided to the inverter after the cutoff time has elapsed using the current motor drive information and the output current value stored in the memory.
The method of claim 7, wherein
And controlling the duty ratio of the PWM signal by calling an Interrupt Service Routine (ISR) when the fault signal is generated.
The method of claim 7, wherein
Determining whether the output current of the inverter is an overcurrent
Detecting an output current of the inverter; And
And determining the output current as an overcurrent when the detected output current exceeds a preset value for a preset time.
The method of claim 7, wherein
Controlling the duty ratio of the PWM signal provided to the inverter
Estimating an electric angle position of the rotor in the motor based on at least one of an output current and an output voltage of the inverter;
Calculating a speed of the rotor based on at least one of the estimated electric angle position and an output voltage of the inverter;
Generating a current command value based on the calculated speed and a target speed value of the motor and generating a voltage command value based on the generated current command value and the output current value stored in the memory; And
And controlling the duty ratio of the PWM signal provided to the inverter after the cutoff time has elapsed according to the generated voltage command value.

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