Motor driving device and method

Abstract

An embodiment of the present invention relates to a motor driving device, comprising: an inverter which generates a driving voltage according to a pulse width modulation (PWM) signal for controlling the driving of a brushless direct current (DC) motor, and supplies the driving voltage to the brushless DC motor; the detection part is used for detecting phase voltage and phase current of the brushless direct current motor; and a control unit that generates the pulse width modulation signal by receiving a target speed of the brushless direct current motor, calculates a zero cross delay value of the phase current with respect to the phase of the phase voltage using a zero cross point of the phase of the phase voltage and the phase current detected by the detection unit, and outputs a zero cross delay value of the phase current with respect to the phase of the phase voltage using the calculated zero cross delay value. And judging the load applied to the brushless direct current motor by using the zero cross delay value and the duty ratio of the pulse width modulation signal.

Description

TECHNICAL FIELD

[0001] The present embodiment relates to a motor drive device and method. BACKGROUND

[0002] Recently, in various electronic devices including a washing machine, a dryer, and the like, a brushless direct current (BLDC) motor having high energy efficiency because of no commutator brush is generally used.

[0003] A common method of controlling such a brushless direct current motor is a feedback control method, that is, an output value output when actually driving the motor is caused to follow an instruction value input in order to drive the motor.

[0004] Since the feedback control method as described above causes the output value to follow the instruction value by only changing a torque or a speed of the motor or the like in a state where a load applied to the motor is unclear, it is possible to cause a control accuracy of the brushless direct current motor to decrease. SUMMARY

[0005] In this background, an object of the present embodiment is to provide a technology of accurately determining a load applied to a brushless direct current motor using a duty ratio of a control signal for controlling the brushless direct current motor, a phase voltage phase of the brushless direct current motor, and a zero cross point of a phase current.

[0006] The object of the present embodiment is not limited to the above-mentioned object, and other objects not mentioned in the present specification can be clearly understood by those skilled in the art through the following description.

[0007] The present embodiment provides a motor drive device including an inverter generating a driving voltage according to a pulse width modulation (PWM) signal for controlling driving of a brushless direct current (BLDC) motor and supplying the driving voltage to the brushless direct current motor, a detection section detecting a phase voltage and a phase current of the brushless direct current motor, and a control section generating the pulse width modulation signal by receiving a target speed of the brushless direct current motor, calculating a zero cross delay value of the phase current with respect to a phase of the phase voltage using a phase of the phase voltage and a zero cross point of the phase current detected by the detection section, and determining an amount of a load applied to the brushless direct current motor using the zero cross delay value and a duty ratio of the pulse width modulation signal.

[0008] According to another embodiment, the present embodiment provides a motor drive method of a motor drive device, including: a generation step of generating a pulse width modulation signal by receiving a target speed of a brushless direct current motor; a supply step of supplying a driving voltage to the brushless direct current motor according to the pulse width modulation signal; a detection step of detecting a phase voltage and a phase current of the brushless direct current motor; a calculation step of calculating a zero-crossing delay value of the phase current with respect to a phase of the phase voltage using a phase of the phase voltage and a zero-crossing point of the phase current at a point in time when an actual speed of the brushless direct current motor reaches the target speed; and a determination step of determining an amount of load applied to the brushless direct current motor using a duty ratio of the pulse width modulation signal confirmed at the point in time when the actual speed of the brushless direct current motor reaches the target speed and the zero-crossing delay value.

[0009] According to the present embodiment as described above, since the amount of load applied to the brushless direct current motor can be accurately determined using the duty ratio of the pulse width modulation signal for controlling the brushless direct current motor, the phase of the phase voltage of the brushless direct current motor, and the zero-crossing point of the phase current, the driving of the motor can be more accurately controlled.

[0010] Since the amount of load applied to the application program can be determined, the execution of the application program function required for the user convenience such as the prediction of the end point of time of the application program can be applied. Also, the user convenience function can be presented in various ways such as the application program operation end time measurement, the application program weighting value measurement, and the automatic movement between the execution sequences by using the load measurement data.

[0011] The various and advantageous advantages and effects of the embodiments are not limited to the above-described contents, and can be more easily understood in the course of describing the specific embodiments of the embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 FIG. 1 is a block diagram of a motor drive device according to an embodiment.

[0013] Figure 2 FIG. 2 is a diagram showing a circuit structure of the motor drive device according to an embodiment.

[0014] Figure 3 FIG. 3 is a block diagram specifically showing a structure of the motor drive device according to an embodiment.

[0015] Figure 4 and Figure 5 FIG. 4 is a diagram for explaining a zero-crossing delay value of a phase current with respect to a phase of a phase voltage.

[0016] Figure 6 FIG. 5 is a diagram exemplarily showing a lookup table according to an embodiment.

[0017] Figure 7A diagram for charting a lookup table of an embodiment.

[0018] Figure 8 A flowchart for showing a process of storing a lookup table in a motor drive device of an embodiment.

[0019] Figure 9 A flowchart for showing a process of determining a load amount in a motor drive device of an embodiment. DETAILED DESCRIPTION

[0020] Hereinafter, some embodiments of the present application will be described in detail with reference to the accompanying drawings. In the process of assigning reference numerals to structural elements in the respective drawings, the same structural elements will be assigned with the same reference numerals even if they appear in different drawings. Also, in the process of explaining the present application, if it is judged that a detailed explanation of a related well-known structure or function can unnecessarily confuse the gist of the present application, the detailed explanation will be omitted.

[0021] Also, in the process of explaining structural elements of the present application, the terms "first", "second", "A", "B", "(a)", "(b)", and the like can be used. Such terms are used only to distinguish the structural elements from other structural elements, and the nature or order or sequence of the corresponding structural elements is not limited to the terms. If it is written that a certain structural element is "connected", "combined", or "coupled" with other structural elements, the structural element can be directly connected or coupled with the other structural elements, but it should be understood that other structural elements can be "connected", "combined", or "coupled" between the respective structural elements.

[0022] Figure 1 A structural diagram of a motor drive device of an embodiment. Figure 2 A diagram for showing a circuit structure of a motor drive device of an embodiment.

[0023] REFERENCE Figure 1 The motor drive device 10 can include driving circuit blocks 200, 300, 400, 500 for driving a brushless direct current (BLDC) motor 100. As an example, the motor drive device 10 can drive a sensorless brushless direct current motor 100.

[0024] The motor drive device 10 as described above can include an inverter 200 for transmitting a driving voltage to the brushless direct current motor 100, a voltage detection part 110 for detecting a phase voltage Vu output from the brushless direct current motor 100, a current detection part 120 for detecting a phase current Iu output from the brushless direct current motor 100, and a control part 400 for controlling the inverter 200 in order to drive the brushless direct current motor 100.

[0025] In one embodiment, for the sake of convenience of explanation, the phase voltage of the U phase is detected by the voltage detection section 110 and the phase current of the U phase is detected by the current detection section 120, but one embodiment is not limited thereto, and the voltage detection section 110 and the current detection section 120 can detect the phase voltage and the phase current of the V phase or the W phase. Also, the voltage detection section 110 and the current detection section 120 can be simply denoted by the detection sections 110, 120.

[0026] The control section 400 can be connected to a memory 500. The memory 500 can be provided outside the control section 400. Also, the memory 500 can be built in the control section 400 together with the control section 400 in a semiconductor chip such as a micro controller unit (MCU) or a motor driver integrated circuit (Driver IC). In other words, the motor drive device 10 can be a micro controller unit or a motor driver integrated circuit.

[0027] Such a memory 500 can be embodied by an electrically erasable and programmable read only memory (EEPROM).

[0028] In one embodiment, as shown in FIG. 1, the brushless direct current motor 100 can include a stator provided with three-phase coils (UC, VC, WC) of different phases and a rotor made of a permanent magnet. Figure 2

[0029] The stator of the brushless direct current motor 100 can include a first coil UC having the U phase, a second coil VC having the V phase, and a third coil WC having the W phase. The brushless direct current motor 100 can be driven according to a driving voltage supplied from the inverter 200 to the three-phase coils (UC, VC, WC) respectively. In this case, the magnetic force generated in the first coil UC, the second coil VC, and the third coil WC can make the rotor of the brushless direct current motor 100 rotate.

[0030] The inverter 200 generates a driving voltage according to a pulse width modulation signal for controlling the driving of the brushless direct current motor 100 and supplies the driving voltage to the brushless direct current motor 100.

[0031] Specifically, according to the control of the control section 400, the inverter 200 can supply a first driving voltage VDD or a second driving voltage VSS to the three-phase coils (UC, VC, WC) of the brushless direct current motor 100 through the first phase U, the second phase V, and the third phase W respectively. The inverter 200 can also make the corresponding coil float without supplying the first driving voltage VDD or the second driving voltage VSS.

[0032] ​The inverter 200 receives supply of the first driving voltage VDD and the second driving voltage VSS from the power supply section VDC. The inverter 200 can receive the 1-1 pulse width modulation signal UP and the 1-2 pulse width modulation signal UN, the 2-1 pulse width modulation signal VP and the 2-2 pulse width modulation signal VN, the 3-1 pulse width modulation signal WP and the 3-2 pulse width modulation signal WN from the control section 400.

[0033] Such an inverter 200 can include a first pull-up transistor Tup and a first pull-down transistor Tun serially connected between a supply line of the first driving voltage VDD and a supply line of the second driving voltage VSS for driving the first coil UC of the brushless DC motor 100.

[0034] Also, the inverter 200 can include a second pull-up transistor Tvp and a second pull-down transistor Tvn serially connected between a supply line of the first driving voltage VDD and a supply line of the second driving voltage VSS for driving the second coil VC of the brushless DC motor 100.

[0035] The inverter 200 can include a third pull-up transistor Twp and a third pull-down transistor Twn serially connected between a supply line of the first driving voltage VDD and a supply line of the second driving voltage VSS for driving the third coil WC of the brushless DC motor 100.

[0036] The control section 400 can detect the phase voltage and the phase current of the brushless DC motor 100 through the detection sections 110, 120. In this case, the phase voltage and the phase current (e.g., Vu / Iu) detected by the detection sections 110, 120 can be converted into a digital signal through the analog-digital (AD) converter 300 and input to the control section 400.

[0037] In the case where the electronic device in which the brushless DC motor 100 is installed is driven by a user, as an example, in the case where a home appliance is driven, the control section 400 can generate the pulse width modulation signals according to a target speed (Target speed) set by an instruction of the user. Figure 3

[0038] ​In other words, if the user sets the driving stage (work level) of the electronic device or automatically sets the driving stage at the upper control terminal and then operates the electronic device, the control unit 400 can generate a pulse width modulation signal according to the target speed corresponding to the corresponding work level. Also, the control unit 400 can transmit the pulse width modulation signal to the inverter 200. The home appliance can be a washing machine, a dryer, etc. equipped with the brushless DC motor 100.

[0039] In an embodiment, the control unit 400 can calculate the zero-crossing delay value of the phase current with respect to the phase of the phase voltage using the phase of the phase voltage and the zero-crossing point of the phase current detected by the detection units 110 and 120. Also, the control unit 400 can calculate the zero-crossing delay value of the phase current using the phase of the phase voltage and the zero-crossing point of the phase current if the actual speed of the brushless DC motor 100 reaches the target speed.

[0040] Also, the control unit 400 can determine the amount of load applied to the brushless DC motor 100 using the zero-crossing delay value and the duty ratio of the pulse width modulation signal.

[0041] Such a control unit 400 can include a structure as shown in Figure 3 .

[0042] Referring to Figure 3 , the control unit 400 can include a proportional-integral controller 410 (PI), a pulse width modulation signal generation unit 420, an induced electromotive force / zero-crossing point (ZCP) detection unit 430, a speed calculation unit 440, and a load estimation unit 450.

[0043] The proportional-integral controller 410 can confirm the difference (error) between the target speed and the actual speed, and can generate a motor speed adjustment value for adjusting the motor speed in such a way that the target speed and the actual speed become the same.

[0044] Also, the proportional-integral controller 410 can generate a lead angle adjustment value that makes the phase of the induced electromotive force detected by the induced electromotive force / zero-crossing point detection unit 430 to be described later and the phase of the phase current the same.

[0045] The proportional-integral controller 410 can generate a proportional-integral control value including the motor speed adjustment value and the lead angle adjustment value and transmit it to the pulse width modulation signal generation unit 420.

[0046] The pulse width modulation signal generation section 420 can determine a pulse width modulation duty according to the proportional integral control value, and generate a pulse width modulation signal having the pulse width modulation duty.

[0047] The back electromotive force / zero cross point detection section 430 can detect a back electromotive force of a certain coil generated in the brushless direct current motor 100.

[0048] Also, the back electromotive force / zero cross point detection section 430 can detect a zero cross point of a phase current. Wherein, as shown in Figure 4 or Figure 5 the zero cross point can mean a time point at which the phase current of the certain coil becomes 0. Also, the back electromotive force can be detected at the zero cross point of the phase current in a state that the certain coil is floating.

[0049] In an embodiment, the back electromotive force / zero cross point detection section 430 can transmit the zero cross point of the phase current to the load estimation section 450, and can transmit the back electromotive force to the speed calculation section 440.

[0050] Also, the back electromotive force / zero cross point detection section 430 can receive the phase voltage from the analog-digital converter 300 to transmit to the load estimation section 450.

[0051] The speed calculation section 440 can calculate an actual speed of the brushless direct current motor 100 using the back electromotive force. Wherein, the back electromotive force and the actual speed of the brushless direct current motor 100 can be proportional.

[0052] The load estimation section 450 can receive the phase voltage from the back electromotive force / zero cross point detection section 430. Also, can receive the zero cross point of the phase current.

[0053] Also, the load estimation section 450 can confirm the duty of the pulse width modulation signal generated by the pulse width modulation signal generation section 420.

[0054] In this way, the load estimation section 450 can calculate a zero cross delay value of the phase current with respect to the phase of the phase voltage using the phase of the phase voltage and the zero cross point of the phase current. Wherein, if the actual speed of the brushless direct current motor 100 reaches the target speed, the load estimation section 450 can calculate the zero cross delay value of the phase current using the phase of the phase voltage and the zero cross point of the phase current.

[0055] Specifically, in a state that the actual speed of the brushless direct current motor 100 reaches the target speed, the load estimation section 450 can calculate the zero cross delay value from a time point at which the phase of the phase voltage reaches 30° to the zero cross point of the phase current.

[0056] For example, as shown in Figure 4As shown, if the time point at which the phase voltage reaches 30° coincides with the zero-crossing point of the phase current, the load estimation unit 450 can calculate the zero-crossing delay value as 0°. Here, the 30° phase of the phase voltage can be considered the standard phase of the phase voltage.

[0057] like Figure 5 As shown, if the time point at which the phase voltage reaches 60° is the same as the zero-crossing point of the phase current, the load estimation unit 450 can calculate it as 30° (60° - reference phase).

[0058] On the other hand, the load estimation unit 450 can also confirm the duty cycle of the pulse width modulation signal generated by the pulse width modulation signal generation unit 420.

[0059] Thus, the load estimation unit 450 can determine the amount of load applied to the brushless DC motor 100 by using the zero crossover delay value of the phase current and the duty cycle of the pulse width modulation signal.

[0060] Specifically, if the load applied to the brushless DC motor 100 increases, the duty cycle of the pulse width modulation signal, which is proportional to the magnitude of the drive voltage, will also increase. Furthermore, if the load applied to the brushless DC motor 100 increases, the zero-crossing delay value of the phase current will also increase.

[0061] Therefore, the load estimation unit 450 can determine the load applied to the brushless DC motor 100 by using one or more of the duty cycle of the pulse width modulation signal proportional to the load amount and the zero crossover delay value of the phase current.

[0062] The load estimation unit 450 can determine the load amount applied to the brushless DC motor 100 by selecting the load amount corresponding to one of the duty cycle of the pulse width modulation signal and the zero crossover delay value of the phase current from the lookup table stored in the memory 500.

[0063] In one embodiment, such as Figure 6 As shown, the lookup table can contain multiple loads, the duty cycle of the pulse width modulation signal corresponding to each load, and the zero cross delay value of the phase current.

[0064] exist Figure 6 as well as Figure 7 In the first duty cycle range of the lookup table, the zero crossover delay value can reach 0°.

[0065] In other words, when the duty cycle of the pulse width modulation signal increases within the first duty cycle range, the zero crossover delay value of the phase current can be maintained at 0°.

[0066] Moreover, such as Figure 6 as well as Figure 7When the duty ratio of the pulse width modulation signal increases in the second duty ratio range, the zero-crossing delay value also increases.

[0067] The first duty ratio range can be 0% or more and less than m% (m is a natural number of 1 or more), and the second duty ratio range can be m% or more and 100% or less.

[0068] For example, in the case where the duty ratio of the pulse width modulation signal is 50%, the zero-crossing delay value of the phase current can be calculated as 0°. Thus, the load estimation unit 450 can estimate the amount of load applied to the brushless DC motor 100 as 50% only by using the duty ratio of the pulse width modulation signal. Figure 6 In this case, the first duty ratio range can be 0% or more and less than 70%, and the second duty ratio range can be 70% or more and 100% or less.

[0069] As described above, since the zero-crossing delay value of the phase current is maintained at 0° in the first duty ratio range, if the duty ratio of the pulse width modulation signal generated by the pulse width modulation signal generation unit 420 is included in the first duty ratio range, the load estimation unit 450 can estimate the amount of load applied to the brushless DC motor 100 only by using the duty ratio of the pulse width modulation signal, without using the zero-crossing delay value of the phase current.

[0070] In other words, if the duty ratio of the pulse width modulation signal is included in the first duty ratio range, the control unit 400 can estimate the amount of load applied to the brushless DC motor 100 only by using the duty ratio of the pulse width modulation signal, without using the zero-crossing delay value of the phase current.

[0071] For example, when the duty ratio of the pulse width modulation signal is 50%, the zero-crossing delay value of the phase current can be calculated as 0°. Thus, the load estimation unit 450 can estimate the amount of load applied to the brushless DC motor 100 as 50% only by using the duty ratio of the pulse width modulation signal.

[0072] If the duty ratio of the pulse width modulation signal reaches a value between 50% and 60%, the load estimation unit 450 can estimate the amount of load applied to the brushless DC motor 100 by interpolation.

[0073] On the other hand, in the second duty ratio range, when the duty ratio of the pulse width modulation signal increases, the zero-crossing delay value also increases, and thus if the duty ratio of the pulse width modulation signal generated by the pulse width modulation signal generation unit 420 is included in the second duty ratio range, the load estimation unit 450 can estimate the amount of load applied to the brushless DC motor 100 by using the zero-crossing delay value of the phase current and the duty ratio of the pulse width modulation signal.

[0074] In other words, if the duty ratio of the pulse width modulation signal is included in the second duty ratio range, the control unit 400 can estimate the amount of load applied to the brushless DC motor 100 by using the zero-crossing delay value of the phase current and the duty ratio of the pulse width modulation signal.

[0075] For example, when the duty ratio of the pulse width modulation signal is 90%, the zero-crossing delay value of the phase current can be calculated as 10°. Accordingly, the load estimation section 450 can judge the amount of load applied to the brushless direct current motor 100 as 70 using the zero-crossing delay value of the phase current and the duty ratio of the pulse width modulation signal.

[0076] If the duty ratio of the pulse width modulation signal is a value between 90% and 100% and the zero-crossing delay value of the phase current is a value between 10° and 20°, the load estimation section 450 can judge the amount of load applied to the brushless direct current motor 100 by interpolation.

[0077] In an embodiment, if the duty ratio of the pulse width modulation signal is 100%, i.e., the duty ratio of the pulse width modulation signal reaches the maximum, the zero-crossing delay value of the phase current can increase more than once.

[0078] For example, as shown in FIGS. 7A and 7B, in the lookup table, when the duty ratio of the pulse width modulation signal is 100%, the zero-crossing delay value increases from 20° to 30° once, and can increase to 35° the second time. Figure 6 Figure 7

[0079] On the other hand, in an embodiment, the lookup table can be stored in the memory 500 by the steps shown in FIG. 8. Figure 8

[0080] Figure 8 A flowchart showing the process of storing the lookup table in the motor drive apparatus in an embodiment.

[0081] First, the motor drive apparatus 10 receives a target speed of a brushless direct current motor, and controls the speed of the brushless direct current motor 100 with a pulse width modulation signal having a pulse width modulation duty ratio according to the target speed (step S810, step S820).

[0082] The motor drive apparatus 10 can control the speed of the brushless direct current motor 100 so that the actual speed reaches the target speed by calculating the actual speed of the brushless direct current motor 100 and comparing it with the target speed (step S830).

[0083] In the step S830, the motor drive apparatus 10 can confirm the duty ratio of the pulse width modulation signal at the point in time when the actual speed reaches the target speed, and calculate the zero-crossing delay value of the phase current to store it in the memory 500 (step S840).

[0084] Further, the motor drive apparatus 10 can store the amount of load matched with the duty ratio and the zero-crossing delay value stored in the memory 500 in the memory 500 (step S850). ​​​

[0085] The motor drive device 10 can repeatedly execute steps S810 to S850 until the lookup table is completed (step S860).

[0086] In other words, steps S810 to S850 can be repeated until the duty cycle reaches 100% from 0%.

[0087] As described above, the motor drive device 10 that stores the lookup table in the memory 500 can, as shown above, store the lookup table in the memory 500 via... Figure 9 The steps shown are for determining the load.

[0088] Figure 9 A flowchart illustrating the process of determining the load amount in a motor drive device according to one embodiment is provided.

[0089] First, the motor drive unit 10 receives the target speed input of the brushless direct current motor and generates a pulse width modulation signal with a pulse width modulation duty cycle based on the target speed to control the speed of the brushless direct current motor 100 (steps S910 and S920).

[0090] In other words, in step S920, the motor drive device 10 generates a drive voltage according to the pulse width modulation signal and supplies it to the brushless DC motor.

[0091] In step S920, the motor drive device 10 can detect the phase voltage and phase current of the brushless DC motor.

[0092] On the other hand, at the point when the actual speed of the brushless DC motor 100 reaches the target speed, the motor drive device 10 can use the phase of the phase voltage and the zero-crossing point of the phase current to calculate the zero-crossing delay value of the phase current relative to the phase of the phase voltage, and confirm the duty cycle of the pulse width modulation signal (steps S930 and S940).

[0093] Subsequently, the motor drive unit 10 can determine the amount of load applied to the brushless DC motor 100 by using the duty cycle of the pulse width modulation signal confirmed at the time point when the actual speed of the brushless DC motor 100 reaches the target speed and the zero crossover delay value.

[0094] Specifically, if the duty cycle of the pulse width modulation signal is within the first duty cycle range of 0% to m% (m is a natural number greater than or equal to 1), the motor drive device 10 can determine the load amount using only the duty cycle of the pulse width modulation signal (step S960). In other words, the load amount can be determined by comparing the duty cycle of the pulse width modulation signal with a lookup table.

[0095] If the duty cycle of the pulse width modulation signal is within the second duty cycle range of m% to 100%, the motor drive device 10 can determine the load amount using the duty cycle of the pulse width modulation signal and the zero crossover delay value (step S970). In other words, the load amount can be determined by comparing the duty cycle of the pulse width modulation signal, the zero crossover delay value, and a lookup table.

[0096] As described above, after determining the load applied to the brushless DC motor 100, the motor drive device 10 can generate a drive voltage by using control parameters that match the load. These control parameters can be stored in the memory 500.

Claims

1. A motor drive device, characterized in that, include: The inverter generates a drive voltage based on a pulse width modulation signal used to control the drive of the brushless DC motor and supplies it to the brushless DC motor. The detection unit is used to detect the phase voltage and phase current of the brushless DC motor; as well as The control unit generates the pulse width modulation signal by receiving the target speed of the brushless DC motor, calculates the zero-crossing delay value of the phase current relative to the phase of the phase voltage using the zero-crossing point of the phase voltage and the phase current detected by the detection unit, and determines the load applied to the brushless DC motor using the zero-crossing delay value and the duty cycle of the pulse width modulation signal.

2. The motor drive device according to claim 1, characterized in that, If the duty cycle is within a first duty cycle range of 0% to m%, the control unit uses only the duty cycle to determine the load amount, where m is a natural number greater than or equal to 1.

3. The motor drive device according to claim 2, characterized in that, If the duty cycle is within a second duty cycle range of m% to 100%, the control unit uses the duty cycle and the zero crossover delay value to determine the load amount.

4. The motor drive device according to claim 2, characterized in that, When the duty cycle increases within the first duty cycle range, the zero crossover delay value remains at 0°.

5. The motor drive device according to claim 3, characterized in that, When the duty cycle increases within the range of the second duty cycle, the zero-crossing delay value also increases.

6. The motor drive device according to claim 5, characterized in that, When the duty cycle is 100%, the zero-crossing delay value increases by more than one time.

7. The motor drive device according to claim 1, characterized in that, The control unit calculates the zero-crossing delay value and confirms the duty cycle at the time point when the actual speed of the brushless DC motor reaches the target speed.

8. A motor driving method for driving a motor, characterized in that, include: The generation step involves generating a pulse width modulation signal by receiving the target speed of the brushless DC motor. The supply step involves generating a drive voltage based on the pulse width modulation signal to supply the brushless DC motor. The detection step involves detecting the phase voltage and phase current of the brushless DC motor. The calculation step involves using the phase of the phase voltage and the zero-crossing point of the phase current to calculate the zero-crossing delay value of the phase current relative to the phase of the phase voltage at the time point when the actual speed of the brushless DC motor reaches the target speed. as well as The determination step uses the duty cycle of the pulse width modulation signal and the zero crossover delay value, which are confirmed at the time when the actual speed of the brushless DC motor reaches the target speed, to determine the load applied to the brushless DC motor.

9. The motor driving method according to claim 8, characterized in that, Following the determination step, the following step is also included: generating the driving voltage by using control parameters that match the load amount.

10. The motor driving method according to claim 8, characterized in that, In the judgment step, If the duty cycle is within a first duty cycle range of 0% to m%, then the motor drive device uses only the duty cycle to determine the load amount, where m is a natural number greater than or equal to 1. If the duty cycle is within a second duty cycle range of m% to 100%, the motor drive device uses the duty cycle and the zero crossover delay value to determine the load.

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