Motor driving device, method for controlling same, and electronic device configured to be driven by motor

Abstract

The present invention is applicable to a motor driving device, and relates to a device for driving, for example, a direct current motor (DC motor), a method for controlling same, and an electronic device configured to be driven by a motor. The present invention relates to a method for controlling initial driving of a motor. The method may comprise the steps of: checking whether a back electromotive force voltage is detected from the motor; detecting the back electromotive force voltage to check the speed and rotation direction of the motor; determining whether the checked rotation direction of the motor is the same as the rotation direction by a currently input command; and driving the motor on the basis of the determination result. The step of driving the motor may comprise: a forward control mode based on the case in which the checked rotation direction of the motor is the same as the rotation direction by the currently input command; and a backward control mode based on the case in which the checked rotation direction of the motor is opposite to the rotation direction by the currently input command.

Description

Motor driving device, control method thereof, and electronic device driven by the motor

[0001] The present invention is applicable to a motor driving device, and relates to, for example, a device for driving a direct current motor (DC motor), a control method thereof, and an electronic device driven by the motor.

[0002] Recently, various electronic devices, including home appliances such as washing machines and refrigerators, are using brushless direct current (BLDC) motors that are energy efficient because they do not use commutation brushes.

[0003] A BLDC motor performs electronic commutation, which changes the direction of the current flowing in the coils of the armature, and can form a continuous rotating magnetic field that rotates the rotor when the position of the rotor and the commutation point coincide.

[0004] These BLDC motors are used in a wide range of applications, from home appliances like refrigerators, air purifiers, and air conditioners to information processing devices. BLDC motors require separate detection devices to detect rotational speed and rotor position.

[0005] A sensorless BLDC motor drive circuit that does not use a separate detection device such as a Hall sensor to detect the position of the rotor can detect the position of the permanent magnet of the rotor by detecting the counter electromotive force formed in the coils of the motor.

[0006] In this way, after detecting the rotation speed and rotor position, the BLDC motor can be controlled normally. That is, after initially detecting the rotation speed and rotor position, the motor can be driven using the proportional-integral control method using that information.

[0007] When initially driving such a BLDC motor, the motor may not be completely stopped or may be in a state where the motor is naturally moving due to wind or disturbance.

[0008] In this way, when driving an electronic device with a BLDC motor while the motor is in operation, if a general initial driving sequence is performed to drive the motor, a startup failure may occur or it may be judged as an error in the electronic device.

[0009] In a typical BLDC motor control process, it can take time for the motor to completely stop after a motor stop command is issued and for operation to resume. This means that it is difficult to quickly and consistently perform the motor stop and restart sequence.

[0010] Figure 1 is a flowchart showing the control process of a typical BLDC motor.

[0011] In the process of controlling a BLDC motor, an alignment process is first performed (S1). This alignment process (S1) can be performed primarily to determine the position of the rotor.

[0012] Afterwards, an open loop control process (S2) can be performed.

[0013] Control methods utilizing counter electromotive force cannot obtain rotor position information when the rotor is stationary or rotating at low speed. Therefore, acceleration can be achieved from a standstill to a constant speed (i.e., a speed at which the counter electromotive force is sufficiently large).

[0014] Next, a closed loop control process (S3) can be performed.

[0015] In this way, by obtaining information about the rotor using the counter electromotive force, the actual speed and position of the rotor can be determined, enabling feedback control of the motor. The motor can then be controlled normally according to user commands.

[0016] However, if this process is performed while the motor is not completely stopped or while the motor is running naturally due to wind or disturbance, a startup failure may occur.

[0017] Therefore, a solution to this problem is required.

[0018] According to one embodiment of the present invention, it is an object to provide a motor driving device, a control method thereof, and an electronic device driven by the motor, which enable initial startup to be performed within a short period of time without stopping the motor.

[0019] In addition, the present invention provides a motor driving device, a control method thereof, and an electronic device driven by a motor, which can check the speed and direction of the motor while the motor is not stopped so that initial starting can be performed.

[0020] In addition, the present invention aims to provide a motor driving device, a control method thereof, and an electronic device driven by a motor, which enable appropriate control according to the rotation direction of the motor while the motor is not stopped.

[0021] As a first aspect of the present invention for achieving the above-described object, the present invention comprises a method for controlling the initial operation of a motor, comprising: a step of checking whether a counter electromotive force voltage is detected from a motor; a step of checking the speed and rotational direction of the motor by detecting the counter electromotive force voltage; a step of determining whether the checked rotational direction of the motor is the same direction as the rotational direction by a currently input command; and a step of driving the motor according to the determination result, wherein the step of driving the motor may include a forward control mode based on a case where the checked rotational direction of the motor is the same as the rotational direction by the currently input command, and a reverse control mode based on a case where the checked rotational direction of the motor is opposite to the rotational direction by the currently input command.

[0022] In an exemplary embodiment, the step of confirming the rotation direction may include a step of confirming a pattern of a three-phase counter electromotive force voltage waveform output from the motor.

[0023] In an exemplary embodiment, the step of confirming the rotation direction can be confirmed by comparing the magnitudes of the second-phase and third-phase counter electromotive force voltages when the first-phase counter electromotive force voltage becomes minimum and maximum.

[0024] In an exemplary embodiment, the step of checking the rotation direction may be determined to be a forward direction if at least one of a first condition in which the second phase voltage is greater than the third phase voltage when the first phase counter electromotive force voltage is minimum and a second condition in which the third phase voltage is greater than the second phase voltage when the first phase counter electromotive force voltage is maximum is satisfied.

[0025] In an exemplary embodiment, the step of checking the rotation direction may be determined to be reverse if at least one of a third condition in which the third phase voltage is greater than the second phase voltage when the first phase counter electromotive force voltage is minimum and a fourth condition in which the second phase voltage is greater than the third phase voltage when the first phase counter electromotive force voltage is maximum is satisfied.

[0026] In an exemplary embodiment, the forward control mode may include a step of aligning the rotor of the motor and controlling the motor through open-loop control based on a case where the speed of the identified motor is below a threshold speed.

[0027] In an exemplary embodiment, the forward control mode may include a step of closed-loop controlling the motor based on a case where the identified speed of the motor is greater than or equal to a threshold speed.

[0028] In an exemplary embodiment, the reverse control mode may include applying a brake pulse until the speed of the identified motor becomes below a threshold speed.

[0029] As a second aspect of the present invention for achieving the above-described object, the present invention provides a driving device for a motor, comprising: an inverter for transmitting a driving signal to a motor; a detection unit for detecting at least one of a current and a voltage of the motor; and a control unit for controlling the inverter, wherein the control unit determines whether a counter electromotive force voltage is detected from the motor, detects the counter electromotive force voltage to determine the speed and rotational direction of the motor, determines whether the determined rotational direction of the motor is the same direction as a rotational direction by a currently input command, and can drive the motor in one of a forward control mode and a reverse control mode according to the determination result.

[0030] In an exemplary embodiment, the control unit may determine the forward direction if at least one of a first condition in which the second phase voltage is greater than the third phase voltage when the first phase counter electromotive force voltage is minimum and a second condition in which the third phase voltage is greater than the second phase voltage when the first phase counter electromotive force voltage is maximum is satisfied.

[0031] In an exemplary embodiment, the control unit may determine the reverse direction if at least one of a third condition that the third phase voltage is greater than the second phase voltage when the first phase counter electromotive force voltage is minimum and a fourth condition that the second phase voltage is greater than the third phase voltage when the first phase counter electromotive force voltage is maximum is satisfied.

[0032] In an exemplary embodiment, the control unit performs the forward control mode based on a case where the rotation direction of the confirmed motor is the same as the rotation direction by the currently input command, and the forward control mode aligns the rotor of the motor based on a case where the speed of the confirmed motor is lower than or equal to a threshold speed, and controls the motor through open-loop control.

[0033] In an exemplary embodiment, the control unit performs the reverse control mode based on a case where the rotation direction of the confirmed motor is opposite to the rotation direction by the currently input command, and the reverse control mode can apply a brake pulse until the speed of the confirmed motor becomes lower than a threshold speed.

[0034] In an exemplary embodiment, the control unit may include an estimation unit that estimates a counter electromotive force voltage from the motor; a calculation unit that calculates a speed and a rotational direction of the motor according to the counter electromotive force voltage estimated by the estimation unit; a PI controller that determines a target speed and phase by checking an error of the counter electromotive force voltage and determines a current reflection speed for controlling to the target speed; and a PWM signal generation unit that generates a PWM signal having a period and a size according to the speed and phase.

[0035] As a third aspect of the present invention for achieving the above-described object, the present invention provides a device driven by a motor, comprising: a motor; an inverter for transmitting a driving signal to the motor; and a detection unit for detecting at least one of a current and a voltage of the motor; and a control unit for controlling the inverter, wherein the control unit determines whether a counter electromotive force voltage is detected from the motor, detects the counter electromotive force voltage to determine the speed and rotational direction of the motor, determines whether the determined rotational direction of the motor is the same direction as a rotational direction by a currently input command, and can drive the motor in one of a forward control mode and a reverse control mode according to a result of the determination.

[0036] According to an exemplary embodiment of the present invention, the following effects are achieved.

[0037] First, initial startup can be achieved quickly when a drive signal is applied to the motor while the motor is not stopped.

[0038] Additionally, initial startup can be accomplished by checking the speed and direction of the motor while the motor is not stopped.

[0039] Additionally, appropriate control can be performed depending on the rotation direction of the motor while the motor is not stopped.

[0040] Additionally, the motor can be operated without starting failure even when the motor is operated in an uncontrolled state.

[0041] Additionally, if a motor initial start command occurs before the rotor comes to a complete stop after a command to stop the motor, control can be performed at the current motor operating speed.

[0042] Furthermore, according to another embodiment of the present invention, there are additional technical effects not mentioned herein. Those skilled in the art will understand these effects upon reading the specification and drawings.

[0043] Figure 1 is a flowchart showing the control process of a typical BLDC motor.

[0044] Fig. 2 is a block diagram showing a motor driving device according to one embodiment of the present invention.

[0045] Fig. 3 is a block diagram showing the circuit configuration of a motor driving device according to one embodiment of the present invention.

[0046] Fig. 4 is a specific block diagram showing a motor driving device according to one embodiment of the present invention.

[0047] Fig. 5 is a flowchart showing a motor driving process of a motor control method according to one embodiment of the present invention.

[0048] Figures 6 to 8 are waveform diagrams for explaining a process of detecting the rotational direction and speed of a motor according to one embodiment of the present invention.

[0049] Fig. 9 is a waveform diagram for explaining a control process of a forward control mode according to one embodiment of the present invention.

[0050] Fig. 10 is a waveform diagram for explaining a control process of a reverse control mode according to one embodiment of the present invention.

[0051] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be assigned the same reference numbers, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably solely for the convenience of writing the specification, and do not in themselves have distinct meanings or roles.

[0052] In addition, when describing the embodiments disclosed in this specification, if it is determined that a detailed description of a related known technology may obscure the gist of the embodiments disclosed in this specification, the detailed description is omitted.

[0053] In addition, it should be noted that the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and should not be construed as limiting the technical ideas disclosed in this specification by the attached drawings.

[0054] Furthermore, although each drawing is described for convenience of explanation, it is also within the scope of the present invention for a person skilled in the art to implement another embodiment by combining at least two drawings.

[0055] Additionally, when an element such as a layer, region or substrate is referred to as existing "on" another element, it will be understood that this may be directly on the other element, or that there may be intermediate elements in between.

[0056] Fig. 2 is a block diagram showing a motor driving device according to one embodiment of the present invention. Fig. 3 is a block diagram showing a circuit configuration of a motor driving device according to one embodiment of the present invention.

[0057] Referring to FIG. 2, a motor driving device (10) according to one embodiment may include driving circuit blocks (200, 300, 400) for driving a motor (100). For example, such a motor driving device (10) may drive a sensorless BLDC (Brushless Direct Current) motor (100). Hereinafter, the motor (100) will be described with reference to an example in which the motor is a BLDC motor.

[0058] A motor driving device (10) such as this may include an inverter (200) that transmits a driving signal to a motor (100), a voltage detection unit (110) that detects voltages (Vu, Vv, Vw) output from the motor (100), a current detection unit (120) that detects currents (Iu, Iv, Iw) output from the motor (100), and a control unit (400) that controls the inverter (200) to drive the motor (100).

[0059] Here, an example of detecting three-phase voltage and current to control a motor (100) is shown. In addition, the voltage detection unit (110) and the current detection unit (120) can be simply expressed as detection units (110, 120). These detection units (110, 120) can detect at least one of the voltage and current output from the motor (100).

[0060] For example, referring to FIG. 3, the motor (100) may include a stator including three-phase coils (UC, VC, WC) having different phases, and a rotor using permanent magnets. Hereinafter, an example of an inverter (200) driving a sensorless BLDC (Brushless Direct Current) motor (100) will be briefly described.

[0061] The stator of the motor (100) may include a first coil (UC) having a U phase (first phase), a second coil (VC) having a V phase (second phase), and a third coil (WC) having a W phase (third phase). The motor (100) may be driven according to a voltage supplied from an inverter (200) to each of the three-phase coils (UC, VC, WC). At this time, a magnetic force generated in the first to third coils (UC, VC, WC) may rotate the rotor of the motor (100).

[0062] The inverter (200) operates under the control of the control unit (400) to supply a first power voltage (VDD) to each of the three-phase coils (UC, VC, WC) of the motor (100) through each of the first to third phases (U, V, W), supply a second power voltage (VSS), or float the corresponding coil without supplying the first and second power voltages (VDD, VSS).

[0063] The inverter (200) receives a first power voltage (VDD) and a second power voltage (VSS) from the power supply (VDC). The inverter (200) can receive first-first and second-second coil control signals (UP, UN), second-first and second-second coil control signals (VP, VN), and third-first and third-second coil control signals (WP, WN) from the control unit (400). The coil control signals (UP, UN, VP, VN, WP, WN) supplied from the controller (400) can be pulse width modulation (PWM) signals.

[0064] The inverter (200) may include a first pull-up transistor (Tup) and a first pull-down transistor (Tun) connected in series between a supply line of a first power voltage (VDD) that drives a first coil (UC) of a motor (100) and a supply line of a second power voltage (VSS).

[0065] Additionally, the inverter (200) may include a second pull-up transistor (Tvp) and a second pull-down transistor (Tvn) connected in series between a supply line of a first power voltage (VDD) that drives a second coil (VC) of the motor (100) and a supply line of a second power voltage (VSS).

[0066] The inverter (200) may include a third pull-up transistor (Twp) and a third pull-down transistor (Twn) connected in series between a supply line of a first power voltage (VDD) and a supply line of a second power voltage (VSS) that drive a third coil (WC) of a motor (100).

[0067] The control unit (400) can detect voltage and current signals detected from the motor (100) through the detection unit (110, 120). At this time, the current and voltage signals (Iu, Iv, Iw / Vu, Vv, Vw) detected by the detection unit (110, 120) can be converted into digital signals through the AD converter (300) and input to the control unit (400).

[0068] When a user drives an electronic device equipped with the motor (100), for example, a home appliance, the control unit (400) can transmit a driving signal to the motor (100) through the inverter (200) in response to a set duty according to a command from the user. That is, for example, the motor driving device (10) including the motor (100) may be an electronic device. For example, the motor driving device (10) may be a home appliance such as a refrigerator, air purifier, air conditioner, etc. that is driven by the motor (100). For example, such a motor driving device (10) may correspond to a device including the motor (100).

[0069] For example, when a user sets the driving level (operating level) of the electronic device to operate the electronic device, the control unit (400) can generate a driving signal for the motor (100) to control the motor (100).

[0070] As an exemplary embodiment, in the process of controlling the motor (100), the control unit (400) may first perform an alignment process to determine the position of the rotor.

[0071] Afterwards, an open loop control process can be performed in the control unit (400).

[0072] Control methods utilizing counter electromotive force cannot obtain rotor position information when the rotor is stationary or rotating at low speed. Therefore, acceleration can be achieved from a standstill to a constant speed (i.e., a speed at which the counter electromotive force is sufficiently large).

[0073] Next, the control unit (400) may perform a closed loop control process. In this way, by obtaining information about the rotor using the counter electromotive force, the actual speed and position of the rotor can be determined, thereby enabling feedback control of the motor (100). Thereafter, the motor (100) can be controlled normally according to user commands.

[0074] When a user stops the operation of the electronic device and the operation of the motor (100) is terminated, the rotor of the motor (100) may gradually stop depending on the type of electronic device. For example, it may take several seconds to several tens of seconds for the motor (100) to actually stop after the driving signal for driving the motor (100) is stopped.

[0075] Meanwhile, even when a driving signal is not applied to the motor (100), a state in which the motor operates naturally due to wind or disturbance may exist.

[0076] In this way, the motor (100) may be driven while the motor (100) is not driven, but while the motor (100) is substantially operating. For example, while the motor (100) is substantially operating, a user may drive an electronic device equipped with the motor (100) to apply a start command (instruction) to the motor (100).

[0077] Then, the control unit (400) can check (confirm) whether a back electromotive force (BEMF) voltage is detected from the motor (100) in response to a start command for driving the motor (100). Whether the back electromotive force voltage is detected can be done through the detection unit (110, 120).

[0078] A back electromotive force (BEMF) signal is a voltage or electromotive force that opposes the current driving it. BEMF is a voltage drop in an alternating current (AC) circuit due to magnetic induction. Typically, when driving a BLDC motor through two of its three coils, for example, a BEMF signal may be received through the unused coil. In this case, the unused coil can be described as floating.

[0079] At this time, when a counter electromotive force voltage is detected from the motor (100), the control unit (400) can use this counter electromotive force voltage to check the speed and rotation direction of the motor (100). For example, the control unit (400) can check the rotation speed and rotation direction of the rotor of the motor (100). The process of checking the rotation speed and rotation direction of the motor (100) in the control unit (400) will be described in detail later with reference to the drawings.

[0080] Thereafter, the control unit (400) can determine whether the rotation direction of the confirmed motor (100) is the same as the rotation direction according to the currently input command (driving command).

[0081] Accordingly, the control unit (400) can control the motor (100) in a forward control mode based on a case where the rotation direction of the confirmed motor (100) is the same as the rotation direction of the currently input command, and in a reverse control mode based on a case where the rotation direction of the confirmed motor (100) is opposite to the rotation direction of the currently input command.

[0082] In an exemplary embodiment, the process of confirming the rotation direction of the motor (100) can be performed by confirming the pattern of the three-phase counter electromotive force voltage waveform output from the motor (100).

[0083] For example, the process of confirming the rotation direction of the motor (100) can be confirmed by comparing the magnitudes of the second-phase and third-phase counter electromotive force voltages when the first-phase counter electromotive force voltage becomes minimum and maximum. Here, as an example, the first-phase, second-phase, and third-phase may correspond to the U-phase, V-phase, and W-phase, respectively, but is not limited thereto.

[0084] In an exemplary embodiment, the process of checking the direction of rotation can be determined as forward if at least one of a first condition that the second phase (e.g., V phase) voltage is greater than the third phase (e.g., W phase) voltage when the first phase (e.g., U phase) counter electromotive force voltage is minimum and a second condition that the third phase (e.g., W phase) voltage is greater than the second phase (e.g., V phase) voltage when the first phase (e.g., U phase) counter electromotive force voltage is maximum is satisfied.

[0085] In an exemplary embodiment, the process of checking the rotation direction can be determined as a reverse direction if at least one of a third condition in which the third phase (e.g., W phase) voltage is greater than the second phase (e.g., V phase) voltage when the first phase (e.g., U phase) counter electromotive force voltage is minimum and a fourth condition in which the second phase voltage (e.g., V phase) is greater than the third phase (e.g., W phase) voltage when the first phase (e.g., U phase) counter electromotive force voltage is maximum is satisfied.

[0086] In this way, when the rotation direction of the motor (100) is confirmed, the control unit (400) can control the motor (100) in a forward control mode based on a case where the rotation direction of the motor (100) is the same as the rotation direction by the currently input command, and in a reverse control mode based on a case where the confirmed rotation direction of the motor (100) is opposite to the rotation direction by the currently input command.

[0087] At this time, in the forward control mode, the control unit (400) can align the rotor of the motor (100) based on the case where the speed of the confirmed motor (100) is below the critical speed, and control the motor (100) through open loop control.

[0088] In an exemplary embodiment, in the forward control mode, the control unit (400) can perform closed loop control of the motor (100) based on the case where the speed of the identified motor is higher than the threshold speed.

[0089] Meanwhile, in the reverse control mode, the control unit (400) can apply a brake pulse until the speed of the identified motor (100) becomes lower than the critical speed.

[0090] In this way, the control unit (400) performs a forward control mode based on a case where the rotation direction of the confirmed motor (100) is the same as the rotation direction by the currently input command, and this forward control mode aligns the rotor of the motor (100) based on a case where the speed of the confirmed motor (100) is below a critical speed, and can control the motor (100) through open-loop control.

[0091] Meanwhile, the control unit (400) performs a reverse control mode based on a case where the rotation direction of the confirmed motor (100) is opposite to the rotation direction by the currently input command, and this reverse control mode can apply a brake pulse until the speed of the confirmed motor (100) becomes lower than a critical speed.

[0092] This process will be described in detail later with reference to the drawings.

[0093] Fig. 4 is a specific block diagram showing a motor driving device according to one embodiment of the present invention.

[0094] Referring to Fig. 4, a specific implementation example of the control unit (400) is illustrated. Here, the control unit (400) can utilize a proportional-integral control method.

[0095] In an exemplary embodiment, the control unit (400) may include an estimation unit (420) that estimates a back electromotive force (BEMF) voltage from a motor (100), a calculation unit (430) that calculates a speed and rotational direction of the motor (100) based on the back electromotive force voltage estimated by the estimation unit (420), and a PI controller (410) that determines a target speed and phase by checking an error of the back electromotive force voltage and determines a current reflection speed for controlling to the target speed.

[0096] In addition, the control unit (400) may be configured to include a PWM signal generation unit (440) that generates a PWM signal having a period and size according to the speed and phase.

[0097] Here, "Desired Duty" may correspond to a user command. When a user command is input, the user command may be connected to a PI controller (410) to determine a target speed of the motor (100) considering the back electromotive force voltage error.

[0098] A PWM signal generating unit (440) can generate a PWM signal having a period and size according to the speed and phase determined in this manner.

[0099] The counter electromotive force voltage can be converted into a digital signal by an AD converter (300) and applied to an estimation unit (420) or a PWM signal generation unit (440).

[0100] Through this process, a PWM signal having a period and size according to a speed and phase determined according to a duty by a user command can be applied to the inverter (200).

[0101] A three-phase voltage is detected through a detection unit (110, 120), and an estimation unit (420) can estimate a three-phase counter electromotive force voltage through the detected three-phase voltage. A calculation unit (430) can calculate the speed and rotational direction of the motor (100) based on the estimated counter electromotive force voltage.

[0102] When initially driving such a motor (100), the motor (100) may not be completely stopped or the motor (100) may be in a state of natural operation due to wind or disturbance.

[0103] In this way, when the motor (100) is operated in an electronic device to which the motor (100) is applied, and the electronic device is driven to drive the motor (100), if a general initial driving sequence is performed, a startup failure may occur or it may be judged as an error in the electronic device.

[0104] In a typical motor (100) control process, after a motor stop command is issued, it may take time for the motor (100) to actually stop completely and then start operating again. In other words, it is difficult to quickly perform the process of the motor (100) stopping and restarting in a consistent sequence.

[0105] However, according to the embodiment of the present invention as described above, the rotation speed and direction of the motor (100) can be determined using the counter electromotive force voltage, and the motor (100) can be controlled in the forward control mode or the reverse control mode accordingly.

[0106] Accordingly, even if the motor (100) is driven while the motor (100) is not stopped, initial startup can be achieved within a short period of time. In this way, appropriate control can be performed according to the rotation direction of the motor (100) while the motor (100) is not stopped.

[0107] In addition, even if the motor (100) is operated in an uncontrolled state, the motor (100) can be operated without starting failure.

[0108] Additionally, if a command to restart the motor (100) occurs before the rotor completely stops after a command to stop the motor (100), control can be performed at the current operating speed of the motor (100).

[0109] Fig. 5 is a flowchart showing a motor driving process of a motor control method according to one embodiment of the present invention.

[0110] Hereinafter, with reference to Fig. 5, the driving process of this motor (100) will be described step by step. This driving process can be performed in the control unit (400) described above.

[0111] When a user stops the operation of the electronic device and the operation of the motor (100) is terminated, the rotor of the motor (100) may gradually stop depending on the type of electronic device. For example, it may take several seconds to several tens of seconds for the motor (100) to actually stop after the driving signal for driving the motor (100) is stopped.

[0112] Meanwhile, even when a driving signal is not applied to the motor (100), a state in which the motor (100) operates naturally due to wind or disturbance may exist.

[0113] In this way, the motor (100) may be driven while the motor (100) is not driven, but while the motor (100) is substantially operating. For example, while the motor (100) is substantially operating, a user may drive an electronic device equipped with the motor (100) to apply a start command (instruction) to the motor (100).

[0114] Then, first, for example, when a start command (command) is applied to the motor (100) while the motor (100) is operating, it is possible to check whether the function of performing control by checking the rotation speed and direction of the motor (100) has been executed (S10).

[0115] When it is confirmed that this function has been executed, it is possible to check (confirm) whether a counter electromotive force (BEMF) voltage is detected from the motor (100) in response to a start command that drives the motor (100) (S20). Whether this counter electromotive force voltage is detected can be done through a detection unit (110, 120).

[0116] When a counter electromotive force voltage is detected from the motor (100), a process of checking the speed and rotation direction of the motor (100) using this counter electromotive force voltage can be performed (S30).

[0117] Afterwards, it can be determined whether the rotation direction of the confirmed motor (100) is the same as the rotation direction by the currently input command (driving command) (S40).

[0118] Accordingly, the motor (100) can be controlled in a forward control mode (S50) based on a case where the rotation direction of the confirmed motor (100) is the same as the rotation direction of the currently input command, and in a reverse control mode (S60) based on a case where the rotation direction of the confirmed motor (100) is opposite to the rotation direction of the currently input command.

[0119] At this time, in the forward control mode (S50), first, it can be determined whether the speed (SPEED) of the confirmed motor (100) is above or below the threshold speed (Threshold) (S51).

[0120] If the speed of the confirmed motor (100) is below the threshold speed, the first motor driving sequence can be performed. That is, the rotor of the motor (100) can be aligned (S53), and the motor (100) can be controlled through open loop control (S54).

[0121] Meanwhile, if the speed of the confirmed motor (100) is greater than the threshold speed, the motor (100) can be immediately controlled in a closed loop. For example, if the speed of the motor (100) is greater than the threshold speed, closed loop control can be performed immediately without going through the alignment and open loop processes. Accordingly, the motor (100) can be normally controlled according to the user's commands.

[0122] In the reverse control mode (S60), first, it can be determined whether the speed (SPEED) of the confirmed motor (100) is above or below the threshold speed (Threshold) (S61).

[0123] At this time, if the speed of the confirmed motor (100) is below the threshold speed, the first motor driving sequence can be performed. That is, according to the forward control mode (S50), the rotor of the motor (100) can be aligned (S53), and the motor (100) can be controlled through open loop control (S54).

[0124] On the other hand, if the speed of the confirmed motor (100) is greater than the threshold speed, a brake pulse can be applied until the speed of the confirmed motor (100) becomes lower than the threshold speed (S62).

[0125] In this way, when the speed of the motor (100) becomes lower than the critical speed by applying a brake pulse (RESET; S63), the rotor of the motor (100) is aligned again according to the forward control mode (S50) (S53), and the motor (100) can be controlled through open loop control (S54).

[0126] Figures 6 to 8 are waveform diagrams for explaining a process of detecting the rotational direction and speed of a motor according to one embodiment of the present invention.

[0127] As described above, the process of confirming the rotation direction of the motor (100) can be accomplished by confirming the pattern of the three-phase counter electromotive force voltage waveform output from the motor (100).

[0128] For example, the process of confirming the rotation direction of the motor (100) can be confirmed by comparing the magnitude of the second-phase and third-phase counter electromotive force voltages when the first-phase counter electromotive force voltage becomes minimum and maximum. Hereinafter, the first, second, and third phases will be described as examples corresponding to the U-phase, V-phase, and W-phase, respectively.

[0129] Referring to Fig. 6, when the U-phase counter electromotive force voltage becomes minimum, if the V-phase voltage is greater than the W-phase voltage (first condition), it can be determined as positive. In addition, when the U-phase counter electromotive force voltage becomes maximum, if the W-phase voltage is greater than the V-phase voltage (second condition), it can be determined as positive.

[0130] Here, a positive judgment can be made if either the first or second condition is met. However, depending on the embodiment, a positive judgment can be made if both the first and second conditions are met to increase judgment accuracy.

[0131] Meanwhile, referring to Fig. 7, when the U-phase counter electromotive force voltage becomes minimum, if the W-phase voltage is greater than the V-phase voltage (third condition), it can be determined as reverse. In addition, when the U-phase counter electromotive force voltage becomes maximum, if the V-phase voltage is greater than the W-phase voltage (fourth condition), it can be determined as forward.

[0132] Here, if either the third or fourth condition is met, the judgment can be made in reverse. However, depending on the embodiment, to increase judgment accuracy, the judgment can be made in reverse if both the third and fourth conditions are met.

[0133] Referring to Fig. 8, speed (rpm) detection can be performed using the time between the minimum or maximum values ​​of the counter electromotive force voltage values ​​of one of the three phases.

[0134] For example, speed (rpm) can be calculated as (1 / Time)*60 / pole, where Time is the time between minimum and maximum values ​​of the back EMF voltage. Poles is the number of poles applied to the motor's stator.

[0135] Fig. 9 is a waveform diagram for explaining a control process of a forward control mode according to one embodiment of the present invention. Fig. 10 is a waveform diagram for explaining a control process of a reverse control mode according to one embodiment of the present invention.

[0136] As described above, the motor (100) can be controlled differently depending on whether the speed (SPEED) of the motor (100) confirmed in the forward control mode (S50) and the reverse control mode (S60) is above or below the threshold speed (Threshold).

[0137] That is, after the process of confirming the rotation speed (period) and direction using the phase BEMF of the motor (100) is completed, the control process of the forward control mode (S50) and the reverse control mode (S60) can be performed.

[0138] Referring to Fig. 9, after the process of confirming the rotation speed (period) and direction using the phase BEMF is completed, a phase control voltage (phase control voltage) for controlling the motor (100) can be applied according to the forward control mode (S50).

[0139] At this time, as described above, the initial motor driving sequence may be performed or the motor (100) may be subjected to closed loop control depending on whether the speed (SPEED) of the confirmed motor (100) is above or below the threshold speed (Threshold).

[0140] Meanwhile, referring to FIG. 10, after the process of confirming the rotation speed (period) and direction using the phase BEMF is completed, the control process of the reverse control mode (S60) can be performed depending on whether the confirmed speed (SPEED) of the motor (100) is above or below the threshold speed (Threshold).

[0141] First, after reverse recognition, if the speed (SPEED) of the confirmed motor (100) is higher than a threshold speed (Threshold), a brake pulse can be applied until the speed of the motor (100) becomes lower than a certain speed. Thereafter, when the speed of the motor (100) becomes lower than the threshold speed (Threshold), the initial motor driving sequence can be performed.

[0142] The above description is merely an example of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention.

[0143] Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of ​​the present invention but to explain it, and the scope of the technical idea of ​​the present invention is not limited by these embodiments.

[0144] The scope of protection of the present invention should be interpreted by the claims below, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. In a method for controlling the initial operation of a motor, A step for checking whether a counter electromotive force voltage is detected from the motor; A step of detecting the counter electromotive force voltage to confirm the speed and rotation direction of the motor; A step of determining whether the rotation direction of the above-mentioned motor is the same as the rotation direction according to the currently input command; and It is configured to include a step of driving the motor according to the above judgment result, The step of driving the above motor is: Forward control mode based on the case where the rotation direction of the motor confirmed above is the same as the rotation direction by the currently input command, and A motor control method characterized in that it includes a reverse control mode based on a case where the rotation direction of the motor confirmed above is opposite to the rotation direction by the currently input command.

2. In the first paragraph, the step of confirming the rotation direction is: A motor control method characterized by comparing and confirming the magnitude of the second-phase and third-phase counter electromotive force voltages when the first-phase counter electromotive force voltage becomes minimum and maximum.

3. In the second paragraph, the step of confirming the rotation direction is: A control method for a motor characterized in that the motor is judged to be in the forward direction when at least one of a first condition that the second phase voltage is greater than the third phase voltage when the first phase counter electromotive force voltage is minimum and a second condition that the third phase voltage is greater than the second phase voltage when the first phase counter electromotive force voltage is maximum is satisfied.

4. In the second paragraph, the step of confirming the rotation direction is: A control method for a motor characterized in that the reverse direction is determined when at least one of a third condition that the third phase voltage is greater than the second phase voltage when the first phase counter electromotive force voltage is minimum and a fourth condition that the second phase voltage is greater than the third phase voltage when the first phase counter electromotive force voltage is maximum is satisfied.

5. In the first paragraph, the forward control mode is A method for controlling a motor, characterized in that it includes a step of aligning the rotor of the motor and controlling the motor through open-loop control based on a case where the speed of the motor confirmed above is below a critical speed.

6. In the first paragraph, the forward control mode is A method for controlling a motor, characterized in that it includes a step of controlling the motor in a closed loop based on a case where the speed of the motor confirmed above is greater than a threshold speed.

7. In the first paragraph, the reverse control mode is A method for controlling a motor, characterized in that it includes a step of applying a brake pulse until the speed of the motor confirmed above becomes lower than a threshold speed.

8. In the motor driving device, an inverter that transmits a driving signal to the motor; and A sensing unit that senses at least one of the current and voltage of the motor; Including a control unit that controls the above inverter, The above control unit, A motor driving device characterized in that it checks whether a counter electromotive force voltage is detected from the motor, detects the counter electromotive force voltage to check the speed and rotation direction of the motor, determines whether the confirmed rotation direction of the motor is the same direction as the rotation direction according to the currently input command, and drives the motor in one of the forward control mode and the reverse control mode according to the determination result.

9. In the 8th paragraph, the control unit is characterized in that it determines the direction to be positive when at least one of a first condition in which the second phase voltage is greater than the third phase voltage when the first phase counter electromotive force voltage is minimum and a second condition in which the third phase voltage is greater than the second phase voltage when the first phase counter electromotive force voltage is maximum is satisfied.

10. In the 8th paragraph, the control unit determines the reverse direction when at least one of a third condition in which the third phase voltage is greater than the second phase voltage when the first phase counter electromotive force voltage is minimum and a fourth condition in which the second phase voltage is greater than the third phase voltage when the first phase counter electromotive force voltage is maximum is satisfied. A motor driving device characterized in that the control unit determines the reverse direction.

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