KR20200039348A - Cleaner and and method for controlling the same - Google Patents

Abstract

A vacuum cleaner and a control method thereof are disclosed. According to an embodiment of the present invention, the cleaner includes: a main body including a suction motor for generating suction force; a battery assembly mounted on the main body and including a battery that supplies voltage to the suction motor; an inverter including a switch for connecting voltage supplied from the battery to the suction motor; and a control unit which detects the battery assembly separated from the main body while the suction motor is driven, and outputs a PWM signal for controlling the switch so that the suction motor can be decelerated by using the voltage charged in a capacitor connected to the switch according to the detection.

Description

Cleaner and its control method {CLEANER AND AND METHOD FOR CONTROLLING THE SAME}

The present invention relates to a vacuum cleaner of a main body and a control method thereof, and more particularly, to a vacuum cleaner for driving a suction motor using a battery and a control method thereof.

The vacuum cleaner refers to a device that sucks dust and air using suction power generated by a suction motor mounted inside the cleaner body, separates dust from the air, and collects dust.

These vacuum cleaners are classified into canister cleaners, upright cleaners, stick cleaners, handy cleaners, and robot cleaners. In the case of a canister cleaner, a suction nozzle for sucking dust is provided separately from the cleaner body, and the cleaner body and the suction nozzle are connected to each other by a connecting device. In the case of an upright cleaner, the suction nozzle is rotatably connected to the cleaner body. In the case of a stick cleaner and a handy cleaner, it is used in a state where the user holds the cleaner body by hand. However, in the case of a stick cleaner, the suction motor is disposed close to the suction nozzle (lower center), and in the case of a handy cleaner, the suction motor is disposed close to the gripping portion (upper center). The robot cleaner cleans itself while driving itself through an autonomous driving system.

Meanwhile, in the case of a vacuum cleaner, it can be driven in a wireless manner using a battery without a cord for ease of use. When the battery is disconnected from the vacuum cleaner while the vacuum cleaner is operating, counter electromotive force is generated in the operating motor. This back EMF is added to the charging voltage of the DC stage capacitor of the inverter circuit to generate a peak, that is, an overvoltage. Accordingly, the risk of component burnout of the inverter circuit in the cleaner increases, which may result in frequent component replacement.

Republic of Korea Patent Publication No. 10-2014-0095581 (2014.08.01)

Accordingly, an object of the present invention is to provide a vacuum cleaner and a method of operating the same, which can prevent component damage of the inverter due to back electromotive force generated in the suction motor even if the battery is disconnected during driving of the suction motor according to the start of cleaning. .

In addition, another object of the present invention can be implemented to detect whether the battery is disconnected while driving the suction motor according to the start of cleaning, and reduce the margin of the voltage capacity of the switching element used in the inverter to improve the inverter efficiency. It is to provide a vacuum cleaner and its operation method.

In addition, another object of the present invention is a vacuum cleaner implemented to prevent the generation of peak voltage and the increase in the inverter volume due to the increase in the breakdown voltage when the battery is disconnected during the driving of the suction motor according to the start of cleaning, and its operation method To provide.

In addition, another object of the present invention is to provide a vacuum cleaner and a method of operating the vacuum cleaner which are advantageous for the life of the inverter and the capacitor by blocking the occurrence of overvoltage regardless of the magnitude of the voltage even if the battery is removed during the operation of the cleaner.

In addition, another object of the present invention, when the battery is removed during the operation of the vacuum cleaner, a vacuum cleaner capable of preventing the occurrence of overvoltage without changing the circuit, such as adding a braking resistor for overvoltage protection by the back EMF generated by the suction motor and its It is to provide a method of operation.

To this end, the vacuum cleaner according to the present invention, the main body including a suction motor for generating a suction force; A battery assembly mounted on the main body and including a battery supplying voltage to the suction motor; An inverter including a switch connecting a supply voltage provided from the battery to the suction motor; And detecting that the battery assembly is separated from the main body while the suction motor is being driven, and controlling the switch so that the suction motor is decelerated by using a voltage charged in a capacitor connected to the switch according to the detection. It comprises a control unit for outputting a PWM signal.

In addition, in one embodiment, the controller is characterized in that for adjusting the duty cycle of the PWM signal in response to the change in the rotational speed of the supply voltage and the suction motor according to the separation of the battery assembly.

In addition, in one embodiment, the switch, the upper and lower switching elements, the control unit, when it is detected that the battery assembly is separated from the main body, the upper switching element of the inverter is off and the lower switching element It is characterized in that it outputs a control signal to reduce the duty cycle of the PWM signal.

In addition, in one embodiment, when the control unit detects that the battery assembly is separated from the main body, the duty cycle of the PWM signal for the lower switching element is reduced to about 1% based on the magnitude of the supply voltage. It is characterized by controlling the switch.

In addition, in one embodiment, the vacuum cleaner, when it is detected that the battery assembly is separated from the main body, the duty cycle of the PWM signal for the lower switching element is adjusted to a smaller amount than before the separation of the battery assembly Is done.

In addition, in one embodiment, the output of the PWM signal for the deceleration driving of the suction motor is characterized in that it is performed until the voltage charged in the capacitor is discharged.

In addition, in one embodiment, the switch includes upper and lower switching elements, and the control unit, when the voltage charged in the capacitor is discharged, the upper switching element of the switch is turned off, the lower switching element of the switch It is characterized in that to stop the drive of the suction motor by controlling to the on state.

In addition, in one embodiment, the rated voltage is applied to the control unit for a predetermined period of time even after the battery assembly is detected to be separated from the main body, and the control unit transmits a PWM signal for controlling the switch by the rated voltage. It is characterized by outputting.

In addition, in one embodiment, the voltage detection means for detecting the magnitude of the supply voltage, and further comprises a speed detection means for detecting the rotational speed of the suction motor, the control unit, the supply detected by the voltage detection means When the magnitude of the voltage is equal to or less than the first reference value and the rotational speed sensed by the speed detection means is greater than or equal to the second reference value, the battery assembly is detected as being separated from the main body.

In addition, in one embodiment, the control unit, if the magnitude of the supply voltage sensed by the voltage detecting means exceeds a first reference value or the rotation speed sensed by the speed detecting means is less than a second reference value, the battery assembly Characterized in that it is determined that is not separated from the body.

A control method of a vacuum cleaner according to an embodiment of the present invention includes driving a suction motor provided in a cleaner body using a supply voltage provided from a battery; Detecting that the battery assembly mounted on the main body is separated from the main body while the suction motor is driven; And outputting a PWM signal for controlling a switch connecting the supply voltage to the suction motor so that the suction motor is decelerated using a voltage charged in a capacitor according to the detection.

In addition, in one embodiment, the step of outputting the PWM signal is characterized in that the upper switching element of the switch is off and the lower switching element of the switch is a step of outputting a control signal to reduce the duty cycle of the PWM signal. do.

According to the vacuum cleaner and the control method thereof according to an embodiment of the present invention, it is possible to detect whether the battery is separated from the cleaner body by monitoring the supply voltage provided to the suction motor and the rotational speed of the motor during the operation of the cleaner.

In addition, by controlling the PWM duty cycle to a predetermined range value only for the lower switching element of the inverter when removing the battery, economically, it is possible to prevent component damage of the inverter due to overvoltage caused by back EMF generated in the suction motor. In addition, the efficiency of the inverter can be improved by reducing the margin of the voltage capacity of the switching element used in the inverter, and generation of overvoltage is blocked irrespective of the magnitude of the voltage, which is advantageous in the life span of the inverter and the capacitor.

1A, 1B, 2A, and 2B are perspective views illustrating a vacuum cleaner and a battery assembly separated from the vacuum cleaner according to an exemplary embodiment of the present invention.
3A and 3B are block diagrams and circuit diagrams showing a driving circuit for driving a suction motor using a battery voltage or a voltage charged in a capacitor in a vacuum cleaner according to an embodiment of the present invention.
4A and 4B are flowcharts for specifically describing a control method for preventing burnout of an inverter when a battery is removed in a vacuum cleaner according to an embodiment of the present invention.
5 is a graph showing the generation of peak voltage when the battery is separated from the conventional vacuum cleaner, and FIG. 6 is a suction motor without generating a peak voltage when the battery is removed while the suction motor is being driven in the vacuum cleaner according to an embodiment of the present invention. It is a graph showing that the operation is stopped.
7 is a graph showing the waveform of the pulse width modulation (PWM) signal associated with FIG. 5, and FIG. 8 is a graph showing the waveform of the PWM signal associated with FIG. 6.
9A and 9B are graphs for explaining a time during which the application of power to the control unit is maintained when the battery is removed while the suction motor is driven in the vacuum cleaner according to an embodiment of the present invention.

Hereinafter, exemplary embodiments disclosed herein will be described in detail with reference to the accompanying drawings, but the same reference numerals will be assigned to the same or similar elements regardless of reference numerals, and redundant descriptions thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and the technical spirit disclosed in the specification is not limited by the accompanying drawings, and all modifications included in the spirit and technical scope of the present invention , It should be understood to include equivalents or substitutes.

1A and 1B show that the battery assembly is separated from a vacuum cleaner according to the present invention, for example a stick cleaner and a stick cleaner.

Referring to FIG. 1A, the stick cleaner 100 includes a cleaner body 10 having a suction motor therein for generating suction power, a suction unit 120 for sucking air containing dust, and the cleaner body 10 ) And an extension tube 17 connecting the suction part 120.

Although not shown, the suction part 120 may be directly connected to the cleaner body 10 without the extension tube 17.

The cleaner body 10 may include a dust container 12 in which dust separated from air is stored. Accordingly, dust introduced through the suction part 20 may be stored in the dust container 12 through the extension tube 17.

A handle 13 for a user to grip may be provided on the outside of the cleaner body 10. The user can perform cleaning while holding the handle 13.

A battery assembly including a rechargeable battery (not shown) may be mounted on the cleaner body 10. To this end, the cleaner body 10 may be provided with a battery accommodating portion 15 in which the battery is accommodated. For example, the battery accommodating portion 15 may be provided under the handle 13.

The battery included in the battery assembly may be connected to the suction part 120 to supply power to the suction part 100. In addition, the battery is built into the main body 10 to supply power to a suction motor (not shown) that generates suction power.

Meanwhile, the input unit 110 may receive a user input for turning on or off the cleaner body 10. In addition, the input unit 110 may receive a user input for adjusting the power level of the suction motor while the suction motor (not shown) is driven according to the cleaning. In addition, the input unit 110 may receive user input for setting and changing various preset cleaning operation modes.

Meanwhile, the battery assembly 190 mounted on the battery accommodating part 15 may be drawn out toward the bottom surface of the battery accommodating part 15 as illustrated in FIG. 1B. Thereby, the battery assembly 190 may be separated from the cleaner body. The battery assembly 190 may be separated from the cleaner body by user manipulation when charging of the battery is required. Alternatively, the battery assembly 190 may be unintentionally separated from the cleaner body due to an unstable seating on the battery receiving portion 15 or a failure of the support means.

2A and 2B show that the battery assembly is separated from another vacuum cleaner, for example, a canister cleaner and a canister cleaner according to an embodiment of the present invention.

Referring to FIG. 2A, the vacuum cleaner may be formed of a structure in which the suction part 120 and the extension tube 140 and the cleaner body 110 are connected through a flexible hose 150. That is, the cleaner body 110 and the suction unit 120 take a separate structure. The user can operate the direction of movement of the suction unit 120 while holding the handle 130. The cleaner main body separated from the suction part 120 moves by moving / rotating the travel parts 111 and 112 in the direction in which the flexible hose 150 is pulled according to the user's manipulation of the handle 130. A battery accommodating space B in which a battery assembly is seated may be provided at a rear portion of the cleaner body 110.

Referring to FIG. 2B, a door may be provided outside the battery accommodating space B. When the door is opened according to user manipulation, the battery accommodating space B is exposed. The battery assembly 190 may be drawn in or out of the exposed battery accommodating space B. When the battery assembly 190 is withdrawn from the battery accommodating space B, it can be said that the battery is separated from the cleaner body 110.

The battery assembly 190 may be taken out of the battery accommodating space B by user manipulation when charging of the battery is required. In addition, when the main body moves according to the operation of the vacuum cleaner in a state where the door of the battery accommodating space B is not closed properly, it may be unintentionally drawn out of the vacuum cleaner main body.

In the present invention, when the battery is unintentionally disconnected during operation of the cleaner or the battery is intentionally disconnected without accidentally turning off the power, a method for preventing damage to the inverter circuit by detecting such battery disconnection has been implemented.

In the case of a vacuum cleaner using a battery, if the battery is disconnected during the operation of the cleaner, the suction motor stops operating. However, if the battery is suddenly disconnected while the suction motor is rapidly rotating, the back EMF generated in the active suction motor and the charging voltage of the DC terminal capacitor of the inverter circuit are added to generate a peak, that is, an overvoltage. This overvoltage increases the risk of component burnout, such as inverters.

In the present invention, in order to prevent component burnout of the inverter circuit due to the occurrence of such a peak, it is easy to detect the disconnection of the battery while the cleaner is operating, and if the battery is detected to be disconnected, PWM (Pulse Width Modulation) for the switch of the inverter circuit By adjusting the duty cycle, the inverter circuit is not burned out even when the battery is suddenly disconnected.

Specifically, the vacuum cleaner according to the present invention is mounted on the body, the battery assembly including a battery for supplying a voltage to the suction motor for generating a suction force; An inverter including a switch for connecting the supply voltage provided from the battery to the suction motor; It includes a control unit that detects that the battery assembly is separated from the cleaner body while the suction motor is driven, and outputs a PWM signal for controlling the switch so that the suction motor is decelerated by using a voltage charged in a capacitor connected to the switch. According to this, even if the battery is removed during the operation of the cleaner, the driving of the suction motor may be stopped without generating overvoltage.

3A is a block diagram showing a process in which a supply voltage provided from a battery of a battery assembly mounted on a cleaner is transferred to an intake motor 170, for example, a BLDC motor through an inverter circuit 160. Meanwhile, the BLDC motor disclosed below may be understood as the suction motor 170. However, the suction motor 170 according to the present invention does not necessarily mean that it is limited to a BLDC motor, and in a range not contradicting the present invention, the suction motor 170 may be interpreted as including a brush-type motor. There will be.

Since the BLDC motor does not have a brush, the suction motor is rotated in such a way that the three phases of u, v, and w are turned to each other (excitation, current is applied) to form a magnetic field. In addition, in the BLDC motor, the stator is made of a coil and the center rotor is made of a permanent magnet. The rotational speed of the BLDC motor can be obtained by detecting the position of the rotor.

The battery assembly 190 includes a battery that supplies voltage to the suction motor when the cleaner is operated. The battery assembly 190 may further include a BMS (Battery Management System) circuit for securing stability and balancing of the battery composed of a plurality of cells.

The voltage charged in the battery is provided as a supply voltage to the input terminal of the inverter switch 160 through a power line, under the control of the BMS. In addition, the supply voltage may have a size of 25V, for example, and may be a maximum of 30V (or 29.4V).

A voltage detection means for detecting the magnitude of the supply voltage, for example, a voltage sensor, may be connected to the power line. In another example, a voltage sensor is connected to the output terminal of the inverter 160 to detect the supply voltage applied to the suction motor 170.

The inverter 160 connects the supply voltage provided from the battery of the battery assembly 190 to the suction motor 170. In addition, the inverter 160 may be implemented as a three-phase inverter to provide a supply voltage for each of the three phases of the BLDC motor.

The controller 180 may control the operation of the battery assembly 190, the inverter 160, and the suction motor 170, and for this, may output a control signal. In addition, in the present invention, the controller 180 may mean a switch control means or a PWM module.

In this case, the controller 180 may output a PWM signal to the inverter 160 or a gate signal to a MOSFET (not shown) connected to the inverter 160 for this purpose.

In a state in which the cleaner is normally operated, the supply voltage provided from the battery of the battery assembly 190 is controlled such that the rotational speed of the BLDC motor reaches the target rotational speed.

Specifically, when the PWM signal output by the controller 180 is transmitted to the gate of the inverter 160 or a MOSFET (not shown) connected to the inverter, the BLDC motor is periodically switched on. At this time, as the duty cycle of the PWM signal increases, the size of the power W applied to the BLDC motor increases correspondingly. Now, when the rotational speed of the BLDC motor reaches the target rotational speed, for power control, the deceleration driving of the motor should be performed. To this end, the controller 180 can reduce the duty cycle of the PWM signal to correspondingly reduce the size of the power W applied to the BLDC motor. This process is repeated while the vacuum cleaner is operating.

On the other hand, if the battery assembly 190 is separated from the cleaner body during the above-described operation of the vacuum cleaner, the duty cycle of the PWM signal corresponds to a change in the supply voltage size and a rotation speed of the suction motor according to the separation of the battery assembly 190. This is adjusted differently. To describe this in more detail, the inverter circuit shown in FIG. 3B will be referred to.

As shown in Figure 3b, the inverter circuit comprises a three-phase inverter having a DC stage capacitor 330 and three pairs of upper and lower switching elements 310 and 320, the supply voltage of which is smoothed and charged. The three pairs of upper and lower switching elements 310 and 320 may be implemented using at least one of an insulated gate bipolar transistor (iGBT), a MOSFET, and a BJT.

In the illustrated inverter circuit, the supply voltage provided through the DC short capacitor 330 is provided to the BLDC motor via the upper switching element 310 and the lower switching element 320. At this time, the PWM signal corresponding to the duty cycle set in advance or calculated according to the rotational speed of the suction motor is output to the upper and lower switching elements 310 and 320, thereby switching the upper and lower switching elements 310 and 320 at a high speed. It turns on / off.

On the other hand, if the battery assembly 190 is separated from the cleaner body during the operation of the cleaner, all of the upper switching elements 310 of the inverter circuit are turned off, thereby turning off. In addition, the lower switching element 320 is not turned off and PWM-controlled at a predetermined duty cycle within about 1% of the supply voltage.

For example, if the supply voltage of the battery is 25V, the lower switching element 320 is turned on and off at a 1% duty cycle compared to 25V after the battery is removed. In addition, for example, if the supply voltage of the battery is 30V, the lower switching element 320 is turned on and off at a 1% duty cycle compared to 30V after the battery is removed.

Accordingly, that the duty cycle of the PWM signal output to the lower switching element 320 is about 1% means that the output is performed in a smaller amount than the duty cycle of the PWM signal output to the lower switching element 320 in the normal state. . Therefore, the duty cycle of the PWM output to the lower switching element 320 is not necessarily limited to 1%.

Once the battery assembly is separated from the cleaner body, the controller 180 outputs a first control signal / first gate signal to switch to the off state to the upper switching element 310 of the inverter circuit, and the lower switching element 320 is A second control signal / second gate signal for performing PWM control with a reduced duty cycle may be output.

In addition, when the duty cycle of the PWM signal output to the lower switching element 320 is about 1%, the amount of the duty cycle is not adjusted according to the magnitude of the input voltage, but the PWM signal is a fixed range / fixed value duty cycle. It means output.

Therefore, the amount of the duty cycle does not vary depending on the magnitude of the supply voltage, and the PWM signal with a duty cycle of a fixed range / fixed value, for example, a duty cycle reduced to about 1%, for the lower switching element 320 of the inverter circuit Is output.

As described above, when the controller 180 of the cleaner detects that the battery assembly 190 is separated from the cleaner body, the duty cycle of the PWM signal for the lower switching element in the inverter circuit is smaller than before the battery assembly 190 is separated. Adjust with.

For example, when the duty cycle performed before the battery assembly 190 is separated is 10%, the PWM signal is output at a 1% duty cycle reduced by about 1/10 after the separation of the battery assembly 190. In addition, if the PWM signal is output at a 15% duty cycle in the normal state, the PWM signal is output at a 1.5% duty cycle reduced by about 1/10 after separation of the battery assembly 190.

After the battery is separated, the phase currents (ias, ibs, ics) are supplied to the motor through PWM control of the lower switching element 320 of the inverter circuit, so that the DC stage capacitor 330 side does not have an overvoltage caused by back EMF. It is excited in the direction of the BLDC motor.

As described above, according to the present invention, when the battery is removed during the operation of the cleaner, only the lower switching element of the inverter controls the PWM duty cycle to a predetermined value compared to the input voltage. Accordingly, economically, it is possible to prevent component damage of the inverter due to overvoltage generated by back EMF generated in the suction motor.

4A and 4B are flowcharts of a control method of a vacuum cleaner according to the present invention.

Referring first to FIG. 4A, a process in which the suction motor provided in the cleaner body 110 is driven according to the operation of the cleaner is started (S10). For example, when the cleaner is powered on and operated, the suction motor is driven.

While the suction motor is driven, a process of detecting that the battery assembly mounted on the cleaner body is separated is performed (S20). Whether the battery assembly is separated from the cleaner body can be detected by monitoring the magnitude of the supply voltage and the rotational speed of the suction motor. Here, the magnitude of the supply voltage can be obtained by adding a voltage sensor to the output terminal of the battery assembly or the input terminal of the inverter circuit. In addition, the rotational speed of the suction motor can be obtained through a current sensor that detects the phase current supplied to the suction motor and / or a position sensor that detects the rotor position of the suction motor.

If the magnitude of the supply voltage is less than a predetermined value and the rotation speed of the suction motor is a normal rotation speed, it is detected that the battery assembly is disconnected during the operation of the cleaner. The size of the supply voltage and the rotational speed of the suction motor to be detected by the separation of the battery assembly will be described in more detail in FIG. 4B.

When it is detected that the battery assembly is disconnected, a process of outputting a switching signal, that is, a PWM signal, is performed so that the suction motor is decelerated by using the voltage charged in the capacitor connected to the inverter (S30).

When the battery assembly is separated, the back electromotive force generated in the suction motor and the charging voltage charged in the capacitor are added for deceleration driving to generate a peak voltage, that is, an overvoltage. For example, if the supply voltage by the battery was provided at 25V, after the separation of the battery assembly is detected, an overvoltage is generated up to about 40-50V instantaneously. This instantaneous overvoltage causes damage to the inverter circuit.

Accordingly, in the present invention, when the battery assembly is disconnected, all of the upper switching elements of the inverter circuit are opened to output a gate signal for controlling in an off state, and the lower switching elements of the inverter circuit reduce the duty cycle of the PWM signal. The control signal / gate signal is output. Accordingly, even after the separation of the battery assembly is sensed, the magnitude of the maximum voltage is generated only up to the supply voltage, for example, 25V.

Next, with reference to FIG. 4B, a method of detecting separation of the battery assembly during operation of the cleaner and a method of controlling the inverter circuit accordingly will be described in more detail.

When the power of the vacuum cleaner is turned on, the vacuum cleaner is operated. Accordingly, the controller 180 of the cleaner determines whether the suction motor is running (S410). While the suction motor is running, the magnitude of the supply voltage of the battery and the rotational speed of the suction motor are continuously monitored to determine if the battery assembly is disconnected from the body.

The size of the supply voltage of the battery can be confirmed by sensing the voltage flowing to the output terminal of the battery included in the battery assembly or the input terminal of the inverter circuit connected to the battery. To this end, a voltage sensor (not shown) may be provided at the output terminal of the battery or the input terminal of the inverter circuit. The magnitude of the supply voltage sensed by the voltage sensor may be referred to as a 'battery detection voltage'. In addition, the rotational speed of the suction motor can be obtained through a current sensor that detects the phase current supplied to the suction motor and / or a position sensor that detects the rotor position of the suction motor.

According to the monitoring of the detection voltage of the battery and the rotational speed of the suction motor, if the battery detection voltage is less than the first reference value and the rotational speed of the suction motor is greater than or equal to the second reference value, the battery is reported to be separated during operation of the cleaner and according to step S440. The inverter circuit is controlled.

Specifically, if the battery detection voltage is less than the first reference value and the rotational speed of the suction motor is greater than or equal to the second reference value (S420), it is determined that the battery is disconnected during the operation of the cleaner.

Here, the first reference value may mean the minimum voltage provided when the charged battery (which may include before the charged battery is discharged) is mounted on the cleaner body. For example, when the input voltage is 25V, the first reference value may be about 18V.

In addition, the second reference value may mean an average rotational speed or a minimum rotational speed of the suction motor driven when the cleaner operates normally. For example, the second reference value may be any value from 6000 to 6600 rpm.

In step S440, the lower switching element of the switch is switched at high speed using a charging voltage charged in a DC terminal capacitor connected to a switch in the inverter. At this time, the duty cycle of the PWM signal for the lower switching element is output in about 1% of the supply voltage. This is operated with a reduced duty cycle than the duty cycle before battery separation, and is performed until the voltage charged in the DC stage capacitor is discharged. When the voltage charged in the capacitor is discharged, the controller 180 of the cleaner maintains an off state of the upper switching element in the inverter circuit, and controls the lower switching element to the on state to stop driving of the suction motor.

Meanwhile, in the present invention, the size of the supply voltage and the rotational speed of the suction motor are continuously monitored during the operation of the cleaner, so that the battery assembly can be detected by itself. To this end, voltage detecting means (eg, a voltage sensor) for detecting the magnitude of the supply voltage and speed detecting means (eg, a position sensor and / or a current sensor) for sensing the rotational speed of the suction motor may be provided.

When the magnitude of the supply voltage sensed by the voltage detecting means is less than the first reference value and the rotational speed sensed by the speed detecting means is greater than or equal to the second reference value, the controller 180 separates the battery assembly from the main body. Sense it.

On the other hand, if the magnitude of the supply voltage sensed by the voltage detecting means exceeds a first reference value and / or the rotational speed sensed by the speed detecting means is less than a second reference value, the controller 180 determines that the battery assembly is a vacuum cleaner. It can be judged that it is not separated from the main body.

In an embodiment, whether the battery is removed from the cleaner body during the operation of the cleaner may be detected through another sensor, for example, a switching sensor that detects the occurrence of a switching signal according to the operation of the detachable button. In addition, when battery separation is detected, a predetermined tone, LED, image, voice, etc. indicating battery separation may be output.

If the rotation speed of the suction motor is less than the second reference value without determining that the battery is separated (S430), the inverter circuit is controlled according to step S450 to stop driving the suction motor. At this time, for example, it may be considered that the cleaner is operating in an abnormal state or that the power of the cleaner is turned off.

In step S450, the upper switching element in the inverter circuit is opened to output a gate signal for controlling the off state (off) and the lower switching element for controlling the on state instead of PWM control. Accordingly, the suction motor is completely stopped.

On the other hand, as a result of the determination in step S430, if the battery detection voltage exceeds the first reference value and the rotation speed of the suction motor is greater than or equal to the second reference value, the cleaner is considered to be operating normally, and the inverter circuit is controlled according to step S460.

In step S460, PWM control is performed on both upper and lower switching elements in the inverter circuit. Specifically, a gate signal for performing PWM control by applying a duty cycle corresponding to a change in the magnitude of the input voltage provided from the battery and the rotational speed of the suction motor (including the change in rotational speed according to the cleaning operation mode) Output.

Hereinafter, Table 1 shows control of the upper and lower switching elements of the inverter according to the state of the battery separation and the state of the suction motor as described above.

Battery disconnected Operation state of suction motor Control of the upper switching element of the inverter Control of the lower switching element of the inverter Battery disconnect detection In operation U, V, W are all off X, Y, Z PWM control - stop U, V, W are all off X, Y, Z are all on - Deceleration drive U, V, W PWM control X, Y, Z PWM control

As can be seen in Table 1, when battery separation is detected from the cleaner body, the upper switch in the inverter circuit is controlled to be off in the same manner as the suction motor is stopped. However, the lower switch in the inverter circuit is switched at high speed according to the PWM control as in the normal operation of the vacuum cleaner. At this time, the duty cycle of the PWM signal for the lower switch in the inverter circuit after the battery disconnection is detected may be adjusted to a reduced amount to about 1/10 compared to before the battery disconnection.

Hereinafter, FIG. 5 is a graph showing generation of peak voltage when the battery is separated from the conventional vacuum cleaner, and FIG. 6 is a suction motor without overvoltage when the battery is removed while the suction motor is being driven in the vacuum cleaner according to an embodiment of the present invention. It is a graph showing that the operation is stopped.

5, in a situation in which the suction motor of the cleaner is driven at 400W, the supply voltage / supply current 501a maintains a constant range value and the battery detection voltage 502a also changes to a constant value, for example, 25V. Is output. In addition, when the battery is disconnected 510, the charging voltage 501b of the DC stage capacitor is added to the back electromotive force of the motor (same size as the above supply voltage), and the output voltage in the form of instantaneous overvoltage is generated and then reduced ( 502b). The back EMF is the EMF generated in the opposite direction when a voltage is applied to the circuit. This means that a voltage proportional to the magnitude of the original current change due to the magnetic field is applied to the inductor, and the voltage opposite to the direction is applied to the inductor, so that when the supply voltage is 25V, the magnitude of the back EMF is 25V. Therefore, it can be said that the instantaneous overvoltage increases to about 50V by adding the charging voltage of the DC stage capacitor.

On the other hand, according to the present invention, in the same situation that is driven to 400W as shown in FIG. 6, before the battery is separated, the supply voltage / supply current 601a maintains a certain range value and the battery detection voltage 502a as in FIG. It is also output at a constant value, for example 25V. However, when the battery is removed 610, as the PWM control is performed using the charging voltage 601b of the DC stage capacitor, the output voltage 602c is gradually reduced over time without the occurrence of overvoltage. The pattern is shown. Accordingly, there is no fear of component burnout due to overvoltage generation.

Meanwhile, although not shown, results as shown in FIGS. 5 and 6 are output even under the condition that the suction motor of the cleaner is driven at 470 W.

FIG. 7 is a graph showing the waveform of the PWM signal related to FIG. 5 extended by reference to the battery separation time, and FIG. 8 is a graph showing the waveform of the PWM signal related to FIG. 6 extended by reference to the battery separation time.

In FIG. 7, when the battery is removed from the cleaner body, the upper switching element is turned off, and the lower switching element is turned on. That is, when the battery is removed during the operation of the cleaner, an operation stop signal is input, and according to the operation stop signal, the duty cycle of the PWM signal of the lower switching element is adjusted from 10% to 100%.

As shown in FIG. 7, the PWM waveforms 703 of the upper and lower switching elements before the battery separation (E), when a certain time has elapsed after the battery separation (E), the PWM waveform of the upper switching element is '0' (zero ), And the PWM waveform of the lower switching element converges to '1'. Then, the battery detection voltage (701a) is reduced after the battery separation (E) (701b) is increased to the overvoltage (701c). After removing the battery, the back EMF generated in the suction motor and the voltage charged in the DC stage capacitor were added to generate a peak voltage of about twice.

However, in the present invention, while 5V power is applied to the controller 180 through the DC terminal capacitor after the battery separation (E) as shown in FIG. 8, the upper switching element is switched to the off state, but the lower switching The device outputs a PWM signal with a 1% duty ratio compared to the supply voltage. Accordingly, the PWM waveform of the upper switching element converges to '0' (zero), but the lower switching element is operated by repeating switching operations of 0 and 1 at a 1% duty ratio. Here, the battery detection voltage 801a is decreased after the battery separation (E) (801b), and then rises only below the original detection voltage 801a without overvoltage. Then, the lower switch of the inverter circuit is driven using the voltage charged in the DC stage capacitor, and accordingly, the suction motor is safely decelerated and driven without burnout of the inverter circuit.

In one embodiment, the control unit 180 continues to perform such PWM signal output until the driving of the suction motor is completely stopped or the capacitor is completely discharged, thereby generating a peak due to the addition of back electromotive force at the suction motor side. I never do that.

Meanwhile, whether the control signal for PWM control of the lower switching element of the inverter circuit can be continuously output only by the voltage charged in the coffee sheet after the battery is removed may be a problem related to a malfunction such as a reset of the control unit. That is, the voltage charged in the DC stage capacitor is discharged after a predetermined time due to battery disconnection, and whether or not this predetermined time is sufficient to perform PWM control of the lower switching element in the inverter circuit according to the present invention may be a problem. .

Thus, in the present invention, even after detecting that the battery assembly 190 is separated from the cleaner body, the rated voltage is applied to the controller 180 for a predetermined time. At this time, a 5V regulator for rated voltage output may be connected to the inverter circuit. The controller 180 may output a PWM signal for controlling a switch in the inverter circuit by the rated voltage.

9A shows the normal distribution of the time (ms) in which power is maintained to the controller 180, that is, the microcomputer after the battery is removed. As shown, it can be seen that the holding time 910 shows the largest distribution at 484 ms under the conditions of 30 repetitive tests, and is 483.7 on average.

9B shows the change in the charging voltage of the DC stage capacitor after battery separation 920 and the retention time of the 5V power applied to the controller 180. After the battery separation 920, the charging voltage of the capacitor is gradually reduced and discharged. Accordingly, the maintenance time 910 of the 5V power supply is maintained for about 483 ms even after the battery separation 920. Then, after the charging voltage of the capacitor is completely discharged, that is, after about 483 ms holding time 910, the 5V voltage is reduced to 3.9V. As such, since it is confirmed that the 5V voltage is maintained for a sufficient time even after the battery separation 920, the PWM control for preventing overvoltage may be performed without problems.

On the other hand, the drive change of the inverter circuit before and after battery separation may be understood as a change in the operation mode. That is, during operation of the vacuum cleaner, PWM control of the switch in the inverter circuit in the first operation mode (PWM control with both of the upper and lower switching elements at a set duty cycle), and when battery separation is detected during operation of the cleaner, the second operation mode (the upper switching element is turned off) The lower switching element can be viewed as PWM control of the switch in the inverter circuit with reduced duty cycle (PWM control).

In addition, in one example, the PWM control may be performed by varying the duty cycle of a certain range / constant value by a predetermined level according to the driving speed of the suction motor before removing the battery. For example, if the battery detachment is detected while the suction motor is driven in the power mode, the load (or load torque) for decelerating and driving the suction motor that is rotating rapidly is large, so the duty cycle is smaller. For example, it can be reduced by 0.8% to prevent burnout of circuit components in a manner that increases the deceleration driving time. Here, the predetermined level may be determined based on the magnitude of the original supply voltage and the duty cycle of a certain range / constant value.

As described above, the vacuum cleaner and its control method according to the present invention, according to the vacuum cleaner and its control method according to an embodiment of the present invention, the supply voltage provided to the suction motor during the operation of the cleaner and the rotational speed of the motor It can be monitored to detect whether the battery is separated from the cleaner body. In addition, by controlling the PWM duty cycle to a predetermined range value only for the lower switching element of the inverter when removing the battery, economically, it is possible to prevent component damage of the inverter due to overvoltage caused by back EMF generated in the suction motor. In addition, the efficiency of the inverter can be improved by reducing the margin of the voltage capacity of the switching element used in the inverter, and generation of overvoltage is blocked irrespective of the magnitude of the voltage, which is advantageous in the life span of the inverter and the capacitor.

The above-described present invention can be embodied as computer readable codes on a medium on which a program is recorded. The computer-readable medium includes any kind of recording device in which data readable by a computer system is stored. Examples of computer-readable media include a hard disk drive (HDD), solid state disk (SSD), silicon disk drive (SDD), ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data storage device. This includes, and is also implemented in the form of a carrier wave (eg, transmission over the Internet). In addition, the computer may include a controller 180 of the cleaner. Accordingly, the above detailed description should not be construed as limiting in all respects, but should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention.

Claims (12)

The main body including a suction motor for generating a suction force;
A battery assembly mounted on the main body and including a battery supplying voltage to the suction motor;
An inverter including a switch connecting a supply voltage provided from the battery to the suction motor; And
PWM for detecting that the battery assembly is separated from the main body while the suction motor is being driven, and controlling the switch so that the suction motor is decelerated by using a voltage charged in a capacitor connected to the switch according to the detection Vacuum cleaner comprising a control unit for outputting a signal. According to claim 1,
The control unit,
And adjusting the duty cycle of the PWM signal in response to a change in the supply voltage and the rotation speed of the suction motor according to the separation of the battery assembly. According to claim 1,
The switch has upper and lower switching elements,
The control unit,
When it is sensed that the battery assembly is separated from the main body, the upper switching element of the inverter is turned off and the lower switching element outputs a control signal that reduces the duty cycle of the PWM signal. According to claim 3,
The control unit,
And detecting that the battery assembly is separated from the main body, controlling the switch so that the duty cycle of the PWM signal for the lower switching element is reduced to about 1% based on the magnitude of the supply voltage. . According to claim 3,
When it is sensed that the battery assembly is separated from the main body, the vacuum cycle of the duty cycle of the PWM signal for the lower switching element is adjusted to a smaller amount than before the separation of the battery assembly. According to claim 1,
The output of the PWM signal for the deceleration driving of the suction motor is performed until the voltage charged in the capacitor is discharged. The method of claim 6,
The switch has upper and lower switching elements,
The control unit,
When the voltage charged in the capacitor is discharged, the upper switching element of the switch is controlled to the off state, and the lower switching element of the switch is controlled to the on state to stop driving of the suction motor. According to claim 1,
The rated voltage is applied to the control unit for a predetermined period of time even after it is detected that the battery assembly is separated from the body.
The control unit, the vacuum cleaner characterized in that it outputs a PWM signal for controlling the switch by the rated voltage. According to claim 1,
Voltage detection means for detecting the magnitude of the supply voltage,
Further comprising a speed detection means for detecting the rotational speed of the suction motor,
The control unit,
If the magnitude of the supply voltage sensed by the voltage detecting means is less than or equal to a first reference value and the rotational speed sensed by the speed detecting means is greater than or equal to a second reference value, the battery assembly is sensed as being separated from the main body. Vacuum cleaner. The method of claim 9,
The control unit,
If the magnitude of the supply voltage sensed by the voltage detecting means exceeds a first reference value or the rotation speed sensed by the speed detecting means is less than a second reference value, determining that the battery assembly is not separated from the main body Vacuum cleaner characterized by. Driving a suction motor provided in the cleaner body using a supply voltage provided from the battery;
Detecting that the battery assembly mounted on the main body is separated from the main body while the suction motor is driven;
And outputting a PWM signal for controlling a switch connecting the supply voltage to the suction motor so that the suction motor is decelerated by using a voltage charged in a capacitor according to the detection. Control method. The method of claim 11,
The step of outputting the PWM signal is
A method of controlling a vacuum cleaner, characterized in that the upper switching element of the switch is turned off and the lower switching element of the switch outputs a control signal for reducing the duty cycle of the PWM signal.

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