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

Abstract

The present invention can be applied to a motor driving device, and relates to a device for driving, for example, a direct current motor (DC motor), a method for controlling the motor, and a device (electronic device) driven by the motor. The invention may provide a method for controlling a motor, the method comprising the steps of: driving the motor according to a duty cycle command; detecting a change amount of a zero phase of a first phase current for driving the motor to obtain a first value; detecting the variable quantity of the maximum level of the first phase current to obtain a second value; and determining that the motor is in a control error state if at least one of the detected first and second values is greater than an error level.

Description

Technical Field

[0001] The present invention can be applied to a motor drive device, for example, a device for driving a direct current (DC) motor, especially a brushless DC (BLDC) motor, a control method of the motor, and an electronic device driven by the motor. Background Art

[0002] Recently, various electronic devices, including household appliances such as washing machines and refrigerators, have been using brushless direct current (BLDC) motors, which do not use commutator brushes and thus have high energy efficiency.

[0003] The BLDC motor performs electronic commutation to change the direction of the current flowing through the armature coil, and when the position of the rotor matches the commutation timing, a continuous rotating magnetic field can be formed to rotate the rotor.

[0004] Such BLDC motors are used in a wide range of fields, not only in household appliances such as refrigerators, air purifiers, and air conditioners, but also in information processing devices. The BLDC motor requires a separate detection device to detect the rotational speed and position of the rotor.

[0005] A sensorless BLDC motor drive circuit that does not use a separate detection device such as a Hall sensor for detecting the rotor position can detect the position of the permanent magnet of the rotor by detecting the back electromotive force (back EMF) generated in the motor coil.

[0006] When a BLDC motor controller is used to drive a BLDC motor, an abnormal state may occur due to foreign matter blocking the motor or damaging the motor.

[0007] If the BLDC motor controller drives the motor without recognizing such an abnormal state, damage to the motor drive IC may occur due to phenomena such as abnormal current or abnormal voltage.

[0008] Therefore, if the BLDC motor is controlled without performing a protection operation in this case, when the motor becomes uncontrollable, a signal that may cause damage to the motor drive unit may be continuously applied, resulting in a defect in the motor drive unit or secondary damage to the application for driving.

[0009] In addition, when determining an abnormal state using the instantaneous change amount of the phase current level, there is a problem that the normal change generated according to the command cannot be distinguished from the abnormal change.

[0010] Therefore, a solution to solve these problems is needed. Summary of the Invention

[0011] Technical Problem

[0012] According to an embodiment of the present invention, the present invention provides a motor driving device, a control method of a motor, and an electronic device driven by the motor that can detect an abnormal state during motor control.

[0013] In addition, the present invention provides a motor driving device, a control method of a motor, and an electronic device driven by the motor that can detect an abnormal state during motor control and respond thereto to perform processing corresponding to an error situation.

[0014] In addition, the present invention provides a motor driving device, a motor control method, and an electronic device driven by the motor that can determine whether an instantaneous change in a phase current during motor control is a normal change caused by a command or a load change or an abnormal change caused by an error environment.

[0015] In addition, according to another embodiment of the present invention, those skilled in the art understand through the entire context of the drawings and the specification that there may be additional technical problems not mentioned herein.

[0016] Technical solution

[0017] To achieve the above object, as a first aspect of the present invention, the present invention may include: in a method of controlling a motor, driving the motor according to a duty ratio command; obtaining a first value by detecting a zero-phase change amount of a first-phase current driving the motor; obtaining a second value by detecting a change amount of a maximum level of the first-phase current; and determining that a control error state exists if at least one of the detected first value and second value is greater than an error level.

[0018] In an exemplary embodiment, obtaining the first value may be obtained by comparing an accumulated average value at zero phase of the first-phase current with an instantaneous change amount of a zero-phase value of the current first-phase current.

[0019] In an exemplary embodiment, obtaining the second value may be obtained by comparing an accumulated average value of the maximum level of the first-phase current with an instantaneous change amount of the maximum level of the current first-phase current value.

[0020] In an exemplary embodiment, if it is determined that a control error state exists, the motor may be stopped or restarted.

[0021] In an exemplary embodiment, obtaining the first value and obtaining the second value may be performed for each cycle of the motor.

[0022] In an exemplary embodiment, the step of obtaining the first value may include: sensing a zero-phase value of a current first-phase current; calculating a cumulative average at the zero-phase of the first-phase current; and comparing the cumulative average at the zero-phase of the first-phase current with the zero-phase value of the current first-phase current.

[0023] In an exemplary embodiment, the step of obtaining the second value may include: sensing a maximum level value of a current first-phase current; calculating a cumulative average of the maximum level of the first-phase current; and comparing the cumulative average of the maximum level of the first-phase current with the maximum level value of the current first-phase current.

[0024] To achieve the above object, as a second aspect of the present invention, the present invention may include, in a motor driving device: an inverter configured to transfer a driving signal to a motor; a sensing part configured to sense at least one of a current and a voltage of the motor; and a controller configured to control the inverter using a phase current sensed by the sensing part, wherein the controller is configured to obtain a first value by detecting a zero-phase change amount of a first-phase current sensed by the sensing part, obtain a second value by detecting a change amount of a maximum level of the first-phase current, and determine that a control error state exists if at least one of the detected first value and second value is greater than an error level.

[0025] In an exemplary embodiment, the controller may obtain the first value by comparing the cumulative average at the zero-phase of the first-phase current with an instantaneous change amount of the zero-phase value of the current first-phase current.

[0026] In an exemplary embodiment, the controller may obtain the second value by comparing the cumulative average of the maximum level of the first-phase current with an instantaneous change amount of the maximum level of the current first-phase current value.

[0027] In an exemplary embodiment, if it is determined that a control error state exists, the controller may stop or restart the motor.

[0028] In an exemplary embodiment, the controller may obtain the first value and the second value for each cycle of the motor.

[0029] In an exemplary embodiment, the controller may include: a PI controller that determines a target speed and a phase by checking a voltage error; a speed calculator that determines a current reflected speed for controlling to the target speed; a PWM signal generator that generates a PWM signal having a period and an amplitude according to the speed and the phase; and a protection controller that stops or restarts the motor if it is determined that a control error state exists.

[0030] In an exemplary embodiment, the controller may sense a zero-phase value of a current of a current first phase, calculate a cumulative average at the zero phase of the current of the first phase, and compare the cumulative average at the zero phase of the current of the first phase with the zero-phase value of the current of the first phase to obtain a first value.

[0031] In an exemplary embodiment, the controller may sense a maximum level value of the current of the first phase, calculate a cumulative average of the maximum level of the current of the first phase, and compare the cumulative average of the maximum level of the current of the first phase with the maximum level value of the current of the first phase to obtain a second value.

[0032] To achieve the above object, as a third aspect of the present invention, the present invention may include, in a device driven by a motor: a motor; an inverter that transmits a driving signal to the motor; a sensing part that senses at least one of a current and a voltage of the motor; and a controller that includes a protection controller that controls the inverter using a phase current sensed by the sensing part and stops or restarts the motor, and the controller may obtain a first value by detecting a zero-phase change amount of a current of a first phase sensed by the sensing part, obtain a second value by detecting a change amount of the maximum level of the current of the first phase, and transmit a signal to the protection controller by determining that a control error state exists when at least one of the detected first value and second value is greater than an error level.

[0033] Technical effects

[0034] According to an exemplary embodiment of the present invention, the following effects are achieved.

[0035] First, according to an embodiment of the present invention, an abnormal state during motor control can be detected.

[0036] In addition, an abnormal state during motor control can be detected and a response can be made to perform processing corresponding to an error situation.

[0037] In addition, it can be determined whether an instantaneous change in a phase current during motor control is a normal change caused by a command or load change or an abnormal change caused by an error environment.

[0038] In addition, according to another embodiment of the present invention, there are additional technical effects not mentioned herein. Those skilled in the art can understand the entire context of the drawings and the specification. Description of the drawings

[0039] Figure 1 is a block diagram showing a motor driving device according to an embodiment of the present invention.

[0040] Figure 2is a block diagram showing the circuit configuration of a motor drive device according to an embodiment of the present invention.

[0041] Figure 3 is a detailed block diagram showing the motor drive device according to an embodiment of the present invention.

[0042] Figure 4 is a flowchart showing a motor control method according to an embodiment of the present invention.

[0043] Figure 5 is a schematic diagram showing a state in which the phase current changes normally through control processing.

[0044] Figure 6 is a schematic diagram showing a state in which the phase current changes abnormally due to abnormal conditions.

[0045] Figure 7 is a graph showing the control period of the motor.

[0046] Figure 8 is a waveform diagram showing a state in which the phase current changes abnormally due to abnormal conditions.

[0047] Figure 9 is Figure 8 an enlarged view of point A of Detailed Embodiments

[0048] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the drawings. However, for the same or similar components, the same reference numerals will be given regardless of which drawing they are in, and their repeated description will be omitted. The suffixes "module" and "section" of the components used in the following description are designated or used interchangeably only for convenience of writing the specification, and they do not have different meanings or functions by themselves. In addition, when describing the embodiments disclosed herein, if it is determined that the detailed description of related known technologies may obscure the gist of the embodiments disclosed herein, the detailed description will be omitted. Additionally, it should be noted that the attached drawings are merely for facilitating the understanding of the embodiments disclosed in this specification, and the technical concept disclosed in this specification should not be construed as being limited by the attached drawings.

[0049] In addition, although each drawing has been described for convenience of explanation, for those skilled in the art, implementing other embodiments by combining at least two or more drawings belongs to the protection scope of the present invention. Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the drawings. However, for the same or similar components, the same reference numerals will be given regardless of which drawing they are in, and their repeated description will be omitted. The suffixes "module" and "section" of the components used in the following description are designated or used interchangeably only for convenience of writing the specification, and they do not have different meanings or functions by themselves.

[0050] In addition, when describing the embodiments disclosed in this specification, if it is determined that a detailed description of related known technologies may obscure the gist of the embodiments disclosed in this specification, the detailed description will be omitted.

[0051] In addition, it should be noted that the attached drawings are only for facilitating the understanding of the embodiments disclosed in this specification, and the technical concept disclosed in this specification should not be construed as being limited by the attached drawings.

[0052] In addition, although each drawing is described for ease of explanation, for those skilled in the art, implementing other embodiments by combining at least two or more drawings belongs to the protection scope of the present invention.

[0053] In addition, when an element such as a layer, a region, or a substrate is referred to as being "on" another element, it can be understood that it is directly on the other element, or there may be an intermediate element between them.

[0054] Figure 1 is a block diagram showing a motor drive device according to an embodiment of the present invention. Figure 2 is a block diagram showing the circuit structure of a motor drive device according to an embodiment of the present invention.

[0055] Referring to Figure 1 , the motor drive device 10 according to the embodiment may include drive circuit blocks 200, 300, 400, 500 for driving the motor 100. For example, such a motor drive device 10 may drive a sensorless BLDC (brushless direct current) motor 100. Hereinafter, an example in which the motor 100 is a BLDC motor will be mainly described.

[0056] Such a motor drive device 10 may include an inverter 200 that transmits a drive signal to the motor 100, a voltage sensing part 110 that senses the voltage Vu output from the motor 100, a current sensing part 120 that senses the current Iu output from the motor 100, and a controller 400 that controls the inverter 200 to drive the motor 100.

[0057] Here, an example of sensing the voltage and current of the U phase in the three phases to control the motor 100 is shown. In addition, the voltage sensing part 110 and the current sensing part 120 may be simply represented as sensing parts 110, 120. Such sensing parts 110, 120 may sense at least one of the voltage and current output from the motor 100.

[0058] For example, referring to Figure 2 , the motor 100 may include a stator having three-phase coils UC, VC, WC with different phases and a rotor using permanent magnets. InFigure 2 In this case, the memory 500 is omitted. Hereinafter, an example of an inverter 200 that drives a sensorless BLDC (brushless direct current) motor 100 will be briefly described.

[0059] 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 also be driven according to the voltage supplied from the inverter 200 to each of the three-phase coils UC, VC, and WC. In this case, the magnetic force generated from the first coil UC, the second coil VC, and the third coil WC may cause the rotor of the motor 100 to rotate.

[0060] The inverter 200 may operate under the control of the controller 400 to supply a first power supply voltage VDD, or a second power supply voltage VSS, or float the corresponding coil without supplying the first power supply voltage VDD and the second power supply voltage VSS to each of the three-phase coils UC, VC, and WC of the motor 100 through each of the first phase U, the second phase V, and the third phase W.

[0061] The inverter 200 receives the first power supply voltage VDD and the second power supply voltage VSS from a power supply VDC. The inverter 200 may receive a first-first coil control signal UP and a first-second coil control signal UN, a second-first coil control signal VP and a second-second coil control signal VN, a third-first coil control signal WP and a third-second coil control signal WN from the controller 400. The coil control signals UP, UN, VP, VN, WP, and WN provided from the controller 400 may be pulse width modulation (PWM) signals.

[0062] The inverter 200 may include a first pull-up transistor Tup and a first pull-down transistor Tun connected in series between a power supply line of the first power supply voltage VDD and a power supply line of the second power supply voltage VSS that drive the first coil UC of the motor 100.

[0063] In addition, the inverter 200 may include a second pull-up transistor Tvp and a second pull-down transistor Tvn connected in series between a power supply line of the first power supply voltage VDD and a power supply line of the second power supply voltage VSS that drive the second coil VC of the motor 100.

[0064] The inverter 200 may include a third pull-up transistor Twp and a third pull-down transistor Twn connected in series between a power supply line of the first power supply voltage VDD and a power supply line of the second power supply voltage VSS that drive the third coil WC of the motor 100.

[0065] The controller 400 may sense voltage and current signals sensed from the motor 100 through the sensing parts 110 and 120. In this case, the current and voltage signals (Iu / Vu; in the case of sensing the U-phase signal) sensed by the sensing parts 110 and 120 may be input to the controller 400 after being converted into digital signals by the AD converter 300.

[0066] When a user operates an electronic device such as a household appliance equipped with the motor 100, the controller 400 may transmit a driving signal to the motor 100 through the inverter 200 corresponding to the duty ratio set by the user's command. That is, for example, the motor driving device 10 including the motor 100 may also be an electronic device. For example, the motor driving device 10 may be a household appliance such as a refrigerator, an air purifier, an air conditioner, etc. driven by the motor 100. For example, such a motor driving device 10 may correspond to a device including the motor 100.

[0067] Therefore, the motor driving device 10 includes the controller 400 that controls the inverter 200. The controller 400 may control the inverter 200 using the phase current sensed by the sensing parts 110 and 120.

[0068] As an exemplary embodiment, the controller 400 may drive the motor 100 according to an input driving command (PWM duty ratio). For example, the controller 400 may use the phase current sensed by the sensing parts 110 and 120 to determine the control state of the motor 100. In other words, the controller 400 may use the phase current sensed by the sensing parts 110 and 120 to determine whether the motor 100 is normally controlled.

[0069] For example, the controller 400 may obtain a first value by detecting the zero-phase change amount (i.e., the value at zero phase of the U-phase current) of the phase current (e.g., U-phase current) sensed by the sensing parts 110 and 120, and obtain a second value by detecting the change amount of the maximum level of the phase current.

[0070] If at least one of the detected first value and second value is greater than a preset error level, the controller 400 may determine that it is in a control error state.

[0071] Hereinafter, as an example, the example of sensing the U-phase current is used to explain the process of determining the control error state in the controller 400.

[0072] In this way, in the controller 400, a first value may be obtained by detecting the zero-phase change amount (i.e., the value at zero phase of the U-phase current) of the U-phase current, and a second value may be obtained by detecting the change amount of the maximum level of the U-phase current.

[0073] As a specific example, the controller 400 can obtain a first value by comparing the cumulative average value at the zero crossing of the U-phase current with the instantaneous change amount of the zero crossing value of the current U-phase current.

[0074] In addition, the controller 400 can obtain a second value by comparing the cumulative average value of the maximum level of the U-phase current with the instantaneous change amount of the maximum level of the current U-phase current value.

[0075] By comparing these first and second values, if at least one of the first and second values is greater than a preset error level, the controller 400 can determine that it is in a control error state.

[0076] In this way, if it is determined that it is in a control error state, the controller 400 can continue to perform processing corresponding to the error situation. For example, if it is determined that it is in a control error state, the controller 400 can stop or restart the motor 100.

[0077] In an exemplary embodiment, the controller 400 can obtain the first and second values for each cycle of the motor 100. For example, the controller 400 can obtain the first and second values for each rotation of the motor 100.

[0078] Therefore, according to an embodiment of the present invention, the abnormal state of the motor 100 can be detected by the controller 400.

[0079] In this case, as described above, the abnormal state of the motor 100 can be detected by comparing the cumulative average value of the phase current with the instantaneous change amount. This is to distinguish the abnormal state from the state of the motor 100 caused by variable load / variable command.

[0080] According to an embodiment of the present invention, the cumulative average value of the phase current can be used as a reference value for comparison in change amount detection. The reason for using the cumulative average value of the phase current is that in the case of variable load or variable command, according to the motor control principle, there is a characteristic that changes with the direction of the changing load or changing command.

[0081] Therefore, by comparing the cumulative average value of the phase current with the instantaneous change amount, it can be determined whether it is a normal change of the current caused by command or load change, or an abnormal change caused by an error environment.

[0082] As a specific example, the controller 400 can sense the zero crossing value of the current U-phase current, calculate the cumulative average value at the zero crossing of the U-phase current, and compare the cumulative average value at the zero crossing of the U-phase current with the zero crossing value of the current U-phase current to obtain a first value.

[0083] In addition, the controller 400 may sense the maximum level value of the current U-phase current, calculate the cumulative average value of the maximum level of the U-phase current, and compare the cumulative average value of the maximum level of the U-phase current with the current maximum level value of the U-phase current to obtain a second value.

[0084] Therefore, at least one of the comparisons of these first and second values can be used to detect an abnormal state of the motor 100 due to an error environment.

[0085] These matters will be described later.

[0086] Figure 3 is a detailed block diagram showing a motor drive device according to an embodiment of the present invention.

[0087] Referring to Figure 3 , a specific embodiment of the controller 400 is shown. Here, the controller 400 may use a proportional-integral control method.

[0088] In an exemplary embodiment, the controller 400 may include: a PI controller 410 that determines a target speed and phase by checking a voltage error; a speed calculator 420 that determines a current reflected speed for controlling to the target speed; and a PWM signal generator 430 that generates a PWM signal having a period and amplitude according to such speed and phase.

[0089] The controller 400 may determine a target speed and phase by checking a back electromotive force (BEMF) voltage error. The back electromotive force (BEMF) voltage may be input to the PI controller 410 through the sensing parts 110, 120 and the AD converter 300.

[0090] In addition, the controller 400 may include a protection controller 440 that stops or restarts the motor 100 if it is determined to be in a control error state by comparing the cumulative average value and the instantaneous change amount of the phase current (e.g., U-phase current) sensed by the sensing parts 110, 120 with a preset value.

[0091] Here, the "desired duty ratio" may correspond to a user command. When a user command is input, the user command may be passed to the PWM signal generator 430.

[0092] The user command may be connected to the PI controller 410 to determine the target speed of the motor 100.

[0093] After that, the speed calculator 420 may determine the current reflected speed for controlling the motor 100 to the target speed. Then, the PWM signal generator 430 may generate a PWM signal having a period and amplitude according to the determined speed and phase.

[0094] In addition, for example, the measurement of the back electromotive force voltage can be performed in a state where no voltage is applied to the U phase (the U phase is floating). That is, when the U phase is floating and no voltage is applied to the U phase, the voltage sensed by the sensing parts 110 and 120 in the U phase corresponds to the back electromotive force (BEMF) voltage.

[0095] This back electromotive force voltage can be applied to the PI controller 410 after being converted into a digital signal by the AD converter 300. The back electromotive force voltage can be detected at the zero crossing point where the phase current switches from the negative phase to the positive phase.

[0096] For example, the back electromotive force voltage Vu detected in the U phase can be compared with the ideal back electromotive force voltage ("desired BEMF voltage") and operated on. The ideal back electromotive force voltage can correspond to Vdd / 2. This condition where the back electromotive force voltage is Vdd / 2 can correspond to the zero crossing point of the U phase current. Therefore, the floating of the U phase can be performed at the zero crossing point of the U phase current. In addition, the phase of the back electromotive force voltage Vu detected in the U phase can be compared with the phase of the ideal back electromotive force voltage ("desired BEMF phase") and operated on.

[0097] Through this process, based on the duty cycle according to the user command, a PWM signal having a period and amplitude according to the speed and phase determined in the controller 400 can be applied to the inverter 200.

[0098] As described above, the controller 400 can determine the state of control error by comparing the cumulative average value and the instantaneous change amount of the phase current (for example, the U phase current) sensed by the sensing parts 110 and 120 with a preset value. For example, this determination of the state of control error can be performed in the PWM signal generator 430 or the protection controller 440.

[0099] In this way, if it is determined that the state is a control error state, the protection controller 440 can continue to perform the processing corresponding to the error situation. For example, if it is determined that the state is a control error state, the protection controller 440 can stop or restart the motor 100.

[0100] Figure 4 It is a flowchart showing a motor control method according to an embodiment of the present invention.

[0101] As described above, the motor control method according to an embodiment of the present invention can be executed in the controller 400. For example, the motor control method according to an embodiment of the present invention can be executed in the PWM signal generator 430 or the protection controller 440.

[0102] Refer to Figure 4, The method for controlling the motor 100 may include: driving the motor according to a duty ratio command in step S10, obtaining a first value by detecting the zero-phase change amount of the first-phase current of the driving motor 100 in step S20, obtaining a second value by detecting the change amount of the maximum level of the first-phase current in step S30, and determining in step S40 whether at least one of the detected first value and second value is greater than an error level, and determining in step S50 that a control error state exists.

[0103] For example, the first phase may be the U phase. For example, in the case of the motor 100 driven by three-phase current, the first phase may also be the V phase or the W phase. Hereinafter, the process of determining the control error state using the U-phase current will be described.

[0104] In an exemplary embodiment, obtaining the first value in step S20 may be obtained by comparing the cumulative average value at the zero phase of the U-phase current with the instantaneous change amount of the zero-phase value of the current U-phase current.

[0105] For example, obtaining the second value in step S30 may be obtained by comparing the cumulative average value of the maximum level of the U-phase current with the instantaneous change amount of the maximum level of the current U-phase current value.

[0106] As described above, in an exemplary embodiment, obtaining the first value in step S20 and obtaining the second value in step S30 may be performed for each cycle of the motor 100.

[0107] As a specific example, obtaining the first value in step S20 may include: sensing the zero-phase value of the current U-phase current (zero-phase sensing) in step S21, calculating the cumulative average value at the zero phase of the U-phase current in step S22, and comparing the cumulative average value at the zero phase of the U-phase current with the zero-phase value of the current U-phase current in step S23.

[0108] As a specific example, obtaining the second value in step S30 may include: sensing the maximum level value of the current U-phase current in step S31, calculating the cumulative average value of the maximum level of the U-phase current in step S32, and comparing the cumulative average value of the maximum level of the U-phase current with the maximum level value of the current U-phase current in step S33.

[0109] Subsequently, in step S40, it may be determined whether at least one of the first value and the second value or the instantaneous change amount at the zero phase and the instantaneous change amount of the maximum level of the U-phase current calculated from the first value and the second value is greater than a specific error level.

[0110] In step S40, if at least one of the first value and the second value, or the instantaneous change amount at the zero crossing of the U-phase current calculated from the first value and the second value and the instantaneous change amount at the maximum level is less than a specific error level, the obtaining of the first value in step S20 and the obtaining of the second value in step S30 can be repeatedly executed.

[0111] However, if at least one of the first value and the second value, or the instantaneous change amount at the zero crossing of the U-phase current calculated from the first value and the second value and the instantaneous change amount at the maximum level is greater than a specific error level, it can be determined in step S50 that it is in a control error state.

[0112] Therefore, when calculating the instantaneous change amount at the zero crossing of the phase current, the cumulative current zero point can be used as a comparison value. In addition, the difference between the current phase current value and the cumulative current zero point can be calculated, and the calculated difference can be determined as the instantaneous change amount at the zero point.

[0113] In this case, the comparison value can be calculated under the following conditions.

[0114] Cumulative average current zero point = (previous cumulative average zero point value + current zero point) / 2

[0115] In addition, for calculating the instantaneous change amount of the maximum current level, the cumulative maximum current level can be used as a comparison value. Additionally, the difference between the current reading and the cumulative current zero point can be calculated, and the calculated difference can be determined as the instantaneous change amount of the maximum current level.

[0116] In this case, the comparison value can be calculated under the following conditions.

[0117] Cumulative average maximum current level = (previous cumulative average maximum current level + current maximum current level) / 2

[0118] Figure 5 is a schematic diagram showing the state where the phase current changes normally through control processing. Figure 6 is a schematic diagram showing the state where the phase current changes abnormally due to abnormal conditions. Figure 7 is a graph showing the control cycle of the motor.

[0119] As described above, the cumulative average value of the phase current can be used as a reference value for comparison in current change amount detection.

[0120] As Figure 5 shown, in the case of variable load or variable command, according to the motor control principle, there is a characteristic that changes with the direction of the changing load or the changing command.

[0121] Referring to Figure 5, the instantaneous change in the phase current increases at a specific point (C, e.g., the current point) during the control period. However, in this case, a state where the cumulative average value also increases is shown. If only the instantaneous change in the phase current at the specific point is used to determine the abnormal state, then Figure 5 the state shown can also be determined as an abnormal state. However, if the cumulative average value of the phase current is considered together, the corresponding situation can correspond to the case of a variable load or a variable command.

[0122] In addition, referring to Figure 6 , it can be seen that a large instantaneous change in the phase current occurs at a specific point (C, e.g., the current point) during the control period. However, different from the Figure 5 case shown, the cumulative average value of the phase current can correspond to a state of no change or a slight change. This situation can be determined as an abnormal change due to an error environment rather than a normal change in the current caused by a command or load change.

[0123] Figure 8 is a waveform diagram showing the state where the phase current changes abnormally due to abnormal conditions. Figure 9 is Figure 8 an enlarged view of point A.

[0124] Referring to Figure 8 and Figure 9 , the PWM command (PWM), the output voltage (Voltage) for driving the motor 100 according to this command, and the U-phase current detected by the sensing parts 110, 120 are shown. That is, the PWM control angles (0 degrees, 180 degrees, 360 degrees) are marked, and it can be seen that the driving voltages are formed with a phase difference at these PWM control angles. In this case, referring to Figure 9 , it can be seen that there is a zero phase of the U-phase current between the control angles of 0 degrees and 180 degrees.

[0125] Referring to Figure 8 , it can be seen that in a state where the PWM command and the output voltage according to the PWM command do not change significantly, the U-phase current increases greatly from the vertical line at part A.

[0126] Referring to Figure 9 which magnifies part A, it can be confirmed that the maximum level of the U-phase current increases sharply. However, in this case, the PWM command or the driving voltage is in a state of no significant change. In addition, it can be seen that the cumulative average value of the U-phase current is in a state of not increasing.

[0127] Therefore, this situation can be determined as an abnormal change due to an error environment rather than a normal change in the current caused by a command or load change.

[0128] Therefore, in part A, by considering both the instantaneous change amount of the phase current and the cumulative average value of the phase current, it is possible to detect an abnormal state caused by an error environment rather than a change in the phase current caused by a variable load or a variable command.

[0129] The above description is only an illustration of the technical idea of the present invention, and those skilled in the art to which the present invention pertains can make various modifications and variations without departing from the basic characteristics of the present invention.

[0130] Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to illustrate the technical idea of the present invention, and the scope of the technical idea of the present invention is not limited by such embodiments.

[0131] The protection scope of the present invention should be interpreted by the appended claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included within the scope of the claims of the present invention.

[0132] Industrial Applicability

[0133] According to the present invention, a device for driving a DC motor (DC motor), a control method of the motor, and a device (electronic device) driven by the motor can be provided.

Claims

1. A method for controlling a motor, the method for controlling the motor comprising the following steps: Drive the motor according to a duty ratio command; Obtain a first value by detecting a zero-phase change amount of a first-phase current driving the motor; Obtain a second value by detecting a change amount of a maximum level of the first-phase current; And If at least one of the detected first value and second value is greater than an error level, determine that a control error state exists.

2. The method for controlling a motor according to claim 1, wherein, Obtaining the first value is achieved by comparing a cumulative average value at the zero phase of the first-phase current with an instantaneous change amount of the zero-phase value of the current first-phase current.

3. The method for controlling an electric machine according to claim 1, wherein, Obtaining the second value is achieved by comparing a cumulative average value of the maximum level of the first-phase current with an instantaneous change amount of the maximum level value of the current first-phase current value.

4. The method for controlling an electric machine according to claim 1, wherein, The step of obtaining the first value comprises the following steps: Sense a zero-phase value of the current first-phase current; Calculate a cumulative average value at the zero phase of the first-phase current; and Compare the cumulative average value at the zero phase of the first-phase current with the zero-phase value of the current first-phase current.

5. The method for controlling a motor according to claim 1, wherein, The step of obtaining the second value comprises the following steps: Sense a maximum level value of the current first-phase current; Calculate a cumulative average value of the maximum level of the first-phase current; and Compare the cumulative average value of the maximum level of the first-phase current with the maximum level value of the current first-phase current.

6. A motor driving device, the motor driving device comprising: An inverter configured to transfer a driving signal to the motor; A sensing part configured to sense at least one of a current and a voltage of the motor; And A controller configured to control the inverter using a phase current sensed by the sensing part, wherein the controller is configured to obtain a first value by detecting a zero-phase change amount of a first-phase current sensed by the sensing part, obtain a second value by detecting a change amount of a maximum level of the first-phase current, and if at least one of the detected first value and second value is greater than an error level, determine that a control error state exists.

7. The motor drive device according to claim 6, wherein, The controller is configured to obtain the first value by comparing a cumulative average value at the zero phase of the first-phase current with an instantaneous change amount of the zero-phase value of the current first-phase current.

8. The motor drive device according to claim 6, wherein, The controller is configured to obtain the second value by comparing a cumulative average value of the maximum level of the first-phase current with an instantaneous change amount of the maximum level value of the current first-phase current value.

9. The motor drive device according to claim 6, wherein The controller is configured to sense a zero-phase value of the current first-phase current, calculate a cumulative average value at the zero phase of the first-phase current, and compare the cumulative average value at the zero phase of the first-phase current with the zero-phase value of the current first-phase current to obtain the first value.

10. The motor drive device according to claim 6, wherein, The controller is configured to sense a maximum level value of the current first-phase current, calculate a cumulative average value of the maximum level of the first-phase current, and compare the cumulative average value of the maximum level of the first-phase current with the maximum level value of the current first-phase current to obtain the second value.

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