KR102161630B1 - Motor drive apparatus performing regenerative breaking - Google Patents

Abstract

The present invention relates to a motor driving apparatus that stores electric energy generated through regenerative braking and provides it to a low power load. The motor driving apparatus according to the present invention includes a control unit that opens both the rectifying unit switch and the switching element included in the inverter when the back EMF voltage of the motor is greater than the voltage of the battery, so that the electric energy generated by regenerative braking the motor is Can be supplied to the battery.

Description

A motor drive apparatus performing regenerative braking TECHNICAL FIELD

The present invention relates to a motor driving apparatus that stores electric energy generated through regenerative braking and provides it to a low power load.

In general, a washing machine is a device that removes contaminants from laundry using the action of detergent and water. Hereinafter, a structure of a conventional washing machine will be described.

1 is an internal configuration diagram of a conventional washing machine. Here, the reference numerals shown in FIG. 1 are limited to the description of FIG. 1.

Referring to FIG. 1, the washing machine is rotatably located inside the casing 2, the storage tank 10, which is installed inside the casing 2 to store the washing water w, and the storage tank 10 ) And a washing tub 20 in which the washing tub 20 is accommodated, and a motor 30 supporting the washing tub 20 and driving rotation.

The casing 2 has an entry hole 2a formed on one surface thereof, and a door 4 for opening and closing the entry hole 2a is mounted.

The door 4 is composed of a door frame 5 rotatably connected to the casing 2 and a door glass 6 mounted on the door frame 5.

In the washing tub 20, an entry hole 21 through which laundry m can be entered is formed, and a hand hole 22 is formed so that the washing water w can flow in and out.

The motor 30 is supported by a bearing 34 on the storage tank 10 while the rotation shaft 32 passes through the storage tank 10, and its tip is connected to the washing tank 20.

In addition, the washing machine further includes a water supply device that supplies washing water (w) supplied from the outside into the reservoir 10, and the water supply device is connected to an external hose and a water supply valve that regulates clean water supplied through the external hose. (42) and a detergent storage space, a water supply passage, and a detergent container 43 formed with a discharge port so as to discharge water supplied to the inside of the washing machine after mixing with the detergent stored in advance.

In addition, the washing machine further includes a drainage device for draining the washing water w in the reservoir 10 to the outside, and the drainage device is a drain hose 45 through which the washing water w of the reservoir 10 is guided. tube), and a drain pump 46 (or drain valve) that pumps (or regulates) drained washing water.

The motor 30 of such a washing machine frequently alternates between forward and reverse rotation due to its operating characteristics. In addition, recently, a geared motor that is coupled with a gear and operates at a high rotational speed (eg, 500 rpm or more) has been mainly used.

Therefore, in the case of the motor 30 used in the washing machine, the braking section appears periodically and frequently, and when the motor 30 is operated at a high rotational speed, the amount of speed change over time is large, which is advantageous for regenerative braking.

However, in a conventional washing machine, when the motor operates at an ultra-high speed, there is a problem that the average amount of power consumption increases.

In addition, conventional washing machines have a problem in that energy efficiency is relatively low because electric energy generated during regenerative braking of a motor cannot be effectively used.

It is an object of the present invention to provide a motor driving device capable of generating energy through regenerative braking in a motor of a washing machine having a large braking section and a large change in speed per hour.

In addition, an object of the present invention is to provide a motor driving device capable of improving energy efficiency by storing electrical energy generated through regenerative braking and providing it to a low power load.

In addition, an object of the present invention is to provide a motor driving apparatus capable of reducing the total amount of power consumption of a washing machine by using energy generated through regenerative braking.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention that are not mentioned can be understood by the following description, and will be more clearly understood by examples of the present invention. In addition, it will be easily understood that the objects and advantages of the present invention can be realized by the means shown in the claims and combinations thereof.

The motor driving apparatus according to the present invention includes a control unit that opens both the rectifying unit switch and the switching element included in the inverter when the back EMF voltage of the motor is greater than the voltage of the battery, so that the electric energy generated by regenerative braking the motor is transferred to the battery. Can be provided.

In addition, the motor driving apparatus according to the present invention includes an SMPS converter that provides a voltage applied to the inverter to a load, and a battery that provides stored electrical energy to the load when the SMPS converter is turned off, thereby reducing energy stored in the battery. Energy efficiency can be improved by providing it to the load.

Further, the motor driving apparatus according to the present invention includes a control unit for regenerative braking the motor by opening a rectifier switch when the back EMF voltage of the motor is greater than the voltage of the capacitor, thereby reducing the total amount of power consumption of the washing machine.

The motor driving apparatus according to the present invention may generate electric energy through regenerative braking in a motor of a washing machine having a frequent braking section and a large change in speed per hour. As the electric energy generated by the motor is used to drive the washing machine, energy efficiency of the washing machine may be improved.

In addition, the motor driving apparatus according to the present invention stores electric energy generated through regenerative braking and provides it to a low-power load, thereby reducing the total amount of power consumption of the washing machine. This can improve product sales in line with the recent trend of preferring low-power products, and can lead to optimal operating efficiency without significantly increasing product production costs.

In addition, the motor driving apparatus according to the present invention may increase energy generated by using the regenerative braking of the motor by being applied to a motor that frequently alternates in a forward direction and a reverse direction due to an operation characteristic and operates at a high speed. Accordingly, when using the product, the electricity cost to be borne by the user may be reduced, and the user's preference for the product may be improved.

In addition to the above-described effects, specific effects of the present invention will be described together while describing specific details for carrying out the present invention.

1 is an internal configuration diagram of a conventional washing machine.
2 is a block diagram showing a motor driving apparatus according to an embodiment of the present invention.
3 is a circuit diagram illustrating the inverter of FIG. 1.
4 is a flowchart illustrating a method of operating a motor driving apparatus according to an embodiment of the present invention.
5 is a block diagram showing a schematic operation of a motor driving apparatus according to an embodiment of the present invention.
6 is a graph illustrating a regenerative braking section of a motor driving apparatus according to an embodiment of the present invention.
7 is a block diagram showing a motor driving apparatus according to another embodiment of the present invention.
8 is a flowchart illustrating a method of operating a motor driving apparatus according to another exemplary embodiment of the present invention.
9 is a block diagram showing a schematic operation of a motor driving apparatus according to another embodiment of the present invention.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only these embodiments make the disclosure of the present invention complete, and are common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used as meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

In the present specification,'generated braking' is an electric braking method that generates a braking force by flowing electric power generated by a motor to a resistance (for example, an internal resistance of the motor) to consume heat, thereby generating a rotational resistance in the motor.

Specifically, in power generation braking, a current flows due to a change in the magnetic flux of the rotor and the formation of a path of each coil, and a braking force opposite to the rotation direction of the rotor is generated by the current flowing through the coil.

Meanwhile, in the present specification,'regenerative braking' is an electric braking method in which a motor is operated as a generator to convert kinetic energy of a rotor into electric energy, and the converted electric energy is recovered to generate braking force.

Hereinafter, when the motor driving device is operated by power generation braking, the motor is braked by consuming power by the internal resistance of the motor without external resistance, and when the motor driving device is operated by regenerative braking, electrical energy generated during braking is stored and utilized. Let's use it as an example.

Further, hereinafter, a motor driving apparatus using regenerative braking according to some embodiments of the present invention will be described with reference to FIGS. 2 to 9.

For reference, the motor driving apparatus described in FIGS. 2 to 9 corresponds to the apparatus for controlling the motor 30 of the washing machine described above with reference to FIG. 1.

2 is a block diagram showing a motor driving apparatus according to an embodiment of the present invention. 3 is a circuit diagram illustrating the inverter of FIG. 1.

Referring to FIG. 2, the motor driving apparatus 1 according to an embodiment of the present invention includes a motor 110, an inverter 120, a control unit 130, a first converter 140, and a battery 150. do. For reference, the motor driving device 1 may further include a second converter 160 and a load 170. Hereinafter, each configuration of the motor driving device 1 will be described in detail.

The rectifying unit 105 rectifies and outputs the commercial AC power supply 101. For example, the rectifier 105 may include a full bridge diode connected to four diodes, but the present invention is not limited thereto, and various modifications may be applied.

The rectifier switch 107 is disposed between the rectifier 105 and the inverter 120. The rectifier switch 107 turns on and off the power transmitted from the rectifier 105 to the inverter 120. The operation of the rectifier switch 107 is controlled by the control unit 130, and when the motor driving device 1 operates by regenerative braking or power generation braking, power transmitted to the inverter 120 may be cut off. A detailed description of this will be described later.

The motor 110 may include a stator in which a three-phase coil (not shown) is wound, and a rotor disposed in the stator and rotating by a magnetic field generated from the three-phase coil. When the three-phase AC voltage (Vua, Vvb, Vwc) is supplied from the inverter 120 to the three-phase coil of the motor 110, the permanent magnet included in the rotor rotates by the magnetic field generated from the three-phase coil.

For reference, the present invention is not limited to a three-phase motor operated by a three-phase coil, for example, a single-phase motor using a single-phase coil may be used. However, in the following, for convenience of explanation, features of the present invention will be described based on a three-phase motor.

The motor 110 may include an induction motor, a blushless DC motor, a reluctance motor, or the like. For example, the motor 110 is a surface-mounted permanent-magnet synchronous motor (SMPMSM), an interior permanent magnet synchronous motor (IPMSM), and a synchronous reluctance motor. (Synchronous Reluctance Motor; Synrm), etc. may be included.

The inverter 120 may include three-phase switch elements (refer to FIG. 3). When an operation control signal (hereinafter referred to as a'PWM (Pulse Width Modulation) signal', hereinafter, a PWM signal) supplied to the control unit 130 is input, the three-phase switch elements operate as a switch on and off, and the input DC The voltage (Vdc) can be converted into a three-phase AC voltage (Vua, Vvb, Vwc) and supplied to a three-phase coil.

Specifically, referring to FIG. 3, the inverter 120 may include three-phase switch elements.

The three-phase switch element is switched on and off by a PWM signal (PWMS) supplied from the control unit 130 to convert the input DC voltage (Vdc) into a three-phase AC voltage (Vua, Vvb, Vwc) having a predetermined frequency or duty. It can be converted to and output to the motor 110.

In the three-phase switch elements, first to third upper arm switches (Sa, Sb, Sc) and the first to third lower arm switches (S'a, S'b, S'b) connected in series with each other are a pair of each other, A total of three pairs of first to third upper arm switches and first to third lower arm switches (Sa&S'a, Sb&S'b, Sc&S'c) may be connected in parallel with each other.

That is, the first phase and lower arm switches (Sa, S'a) are the first phase coil (La) among the three phase coils (La, Lb, Lc) of the motor 110 and the three phase AC voltages (Vua, Vvb, Vwc) ) Of the first phase AC voltage (Vua) is supplied.

In addition, the second upper and lower arm switches Sb and S'b supply the second phase AC voltage Vvb to the second phase coil Lb, and the third and lower arm switches Sc, S'c The third phase AC voltage Vwc may be supplied to the third phase coil Lc.

Here, each of the first to third upper arm switches (Sa, Sb, Sc) and the first to third lower arm switches (S'a, S'b, S'b) is turned on according to the input PWM signal (PWMS) and The motor 110 operates in an OFF state and supplies three-phase AC voltages (Vua, Vvb, and Vwc) to each of the three-phase coils (La, Lb, and Lc) to control the operation of the motor 110.

Referring back to FIG. 2, when a target command value is input, the control unit 130 turns off the ON time interval for the ON operation of each of the three-phase switch elements and the OFF operation based on the target command value and the electric angle position of the rotor. A PWM signal (PWMS) that determines the time section can be output.

The controller 130 may control the operation of the motor 110 by generating the PWM signal PWMS based on the target command value and providing the generated PWM signal PWMS to the inverter 120.

The control unit 130 may receive the command speed and control the operation of the inverter 120 so that the current speed of the motor 110 matches the command speed.

If the control unit 130 receives a stop command whose command speed is less than the reference value (for example, '0'), it can control the inverter 120 so that the current speed of the motor 110 converges to the stop command. have. In this case, the motor driving apparatus 1 may operate as regenerative braking or power generation braking according to the PWM signal PWMs output from the control unit 130.

In addition, the control unit 130 may operate the motor driving device 1 by regenerative braking or power generation braking according to whether the sudden braking signal is received together with the command speed.

A detailed operation control method of the control unit 130 for operating the motor driving device 1 by regenerative braking or power braking will be described later with reference to FIG. 4.

The first converter 140 converts AC power output from the inverter 120 into DC power and provides it to the battery 150. For example, the first converter 140 may charge the battery 150 by converting the three-phase AC voltage (Vua, Vvb, Vwc) output from the inverter 120 into a DC voltage.

For reference, although not clearly shown in the drawings, whether or not the first converter 140 operates may be determined by the controller 130.

Specifically, the controller 130 may determine whether to operate the first converter 140 based on the magnitude of the back EMF voltage generated from the motor 110 and the voltage of the battery 150. That is, the controller 130 operates the first converter 140 to provide DC power to the battery 150 only when the back EMF voltage generated by the motor 110 is greater than the voltage of the battery 150, 150) can be charged.

The battery 150 stores the DC voltage input from the first converter 140. In addition, the battery 150 may provide the stored electrical energy to the load 170. The battery 150 may be a secondary battery capable of charging and discharging, but the present invention is not limited thereto, and all types of batteries capable of charging and discharging electricity may be used.

The second converter 160 converts a first DC voltage (eg, Vdc) applied to the inverter 120 to a second DC voltage applied to the load 170. Here, the second DC voltage is formed relatively smaller than the first DC voltage (eg, Vdc). The converted second DC voltage is provided to the load 170.

In general, the second converter 160 provides power required for the load 170, but when the second converter 160 stops operating, the battery 150 replaces the second converter 160 with the load ( 170) can provide power.

At this time, although not clearly shown in the drawings, the operation of the second converter 160 is controlled by the controller 130. Specifically, when the voltage of the battery 150 is higher than a predetermined reference value or the motor 110 operates by regenerative braking, the controller 130 blocks the supply of power through the second converter 160, and the battery 150 ) Can be controlled to provide power to the load 170.

For reference, the second converter 160 and the battery 150 of the present invention may provide power to the load 170 in various ways. For example, the second converter 160 and the battery 150 may provide power to the load 170 at the same time, and only one of the second converter 160 and the battery 150 selectively loads 170 Can provide power to

The load 170 includes various components included in the motor drive device 1. For example, the load 170 may be a display unit, an interface unit, a communication unit, or a light emitting unit that requires power. In general, the load 170 consumes a certain amount of power, and may operate by receiving power through the battery 150 or the second converter 160.

Additionally, although not clearly shown in the drawings, the motor driving apparatus 1 may further include an input current detection unit, a voltage detection unit, a DC terminal capacitor, a motor current detection unit, an input voltage detection unit, and the like. However, the present invention is not limited thereto, and some of the foregoing additional components may be omitted and implemented.

The input current detection unit can detect an input current input from the commercial AC power supply 101. To this end, a CT (current trnasformer), a shunt resistor, or the like may be used as an input current detection unit. The detected input current is a discrete signal in the form of a pulse and may be input to the controller 130 for power control.

The input voltage detector may detect an input voltage AC input from the commercial AC power supply 101. To this end, the input voltage detector may include a resistance element, an amplifier, or the like. The detected input voltage is a discrete signal in the form of a pulse and may be input to the control unit 130 for power control.

The voltage detector may detect the DC voltage Vdc at both ends of the capacitor. That is, the voltage detector may measure the DC voltage Vdc applied to the input terminal of the inverter 120. The DC voltage Vdc is a discrete signal in the form of a pulse and is provided to the controller 130 to generate a PWM signal PWM. To this end, the voltage detector may include a resistance element, an amplifier, or the like.

The motor current detection unit detects an output current flowing between the inverter 120 and the motor 110. The electric motor current detector may detect a current flowing through the motor 110 (ie, a current delivered to the battery 150 through the first converter 140 in the regenerative braking mode). At this time, the motor current detection unit may detect all of the output currents (ia, ib, ic) of each phase, or may detect the output currents of the two phases using a three-phase balance. The motor current detection unit may be located between the inverter 120 and the motor 110, and a current trnasformer (CT) or a shunt resistor may be used to detect the current.

Accordingly, the control unit 130 uses the input current detected by the input current detection unit, the input voltage detected by the input voltage detection unit, the DC voltage (Vdc) detected by the voltage detection unit, and the output current detected by the motor current detection unit. ), or the counter electromotive force of the motor 110 may be calculated.

4 is a flowchart illustrating a method of operating a motor driving apparatus according to an embodiment of the present invention. 5 is a block diagram showing a schematic operation of a motor driving apparatus according to an embodiment of the present invention. 6 is a graph illustrating a regenerative braking section of a motor driving apparatus according to an embodiment of the present invention.

Referring to FIG. 4, in the motor driving apparatus 1 according to an embodiment of the present invention, first, the control unit 130 receives a stop command from the user (S110). The stop command may be input through the interface unit or may be input to the control unit 130 during a specific program operation.

Subsequently, the control unit 130 determines whether an emergency braking request is received from the user together with the stop command (S120). Here, the sudden braking request corresponds to a command for a quick stop of the operation of the motor driving device 1 in an emergency or at the request of a user, and when there is a sudden braking request, power generation braking is performed for quick braking.

Subsequently, when the sudden braking request is not received, the controller 130 compares the magnitude of the back EMF voltage generated by the motor 110 and the voltage of the battery 150 (S130).

Subsequently, when the back EMF voltage of the motor 110 is greater than the voltage of the battery 150, the control unit 130 opens the rectifier switch 107, and the switch element included in the inverter 120 (for example, the first All of the first to third upper arm switches Sa, Sb, and Sc and the first to third lower arm switches S'a, S'b, S'b) are opened (S140).

Through this, the motor 110 performs regenerative braking (S150). When the motor 110 performs regenerative braking, the electric energy generated by the motor 110 is transferred to and stored in the battery 150 through the first converter 140.

Electrical energy stored in the battery 150 is provided to the load 170 when necessary. For example, when the second converter 160 does not operate normally, or when power in the normal range is not applied to the inverter 120, the battery 150 provides power to the load 170 to provide the motor driving device 1 ) May perform a fail safe operation in which other components included in) operate normally.

On the other hand, when a sudden braking request is received from a user along with a stop command to the control unit 130, or when the back EMF voltage of the motor 110 is less than the voltage of the battery 150, the motor 110 generates and brakes (S160).

When the motor 110 powers braking, the control unit 130 opens all of the first to third upper arm switches Sa, Sb, and Sc of the inverter 120, and the first to third lower arm switches S'a , S'b, S'b) are all shorted. Through this, a closed path for a three-phase coil is formed between the inverter 120 and the motor 110. At this time, a current flows through the motor 110 by the change of the magnetic flux of the motor 110 and the formation of a path of each coil, and a braking force opposite to the rotation direction of the rotor is generated by the current flowing through the coil, so that the motor 110 ) Suddenly brakes.

Referring to FIG. 5, when the motor 110 operates normally, the rectifier switch 107 is short-circuited, and the inverter 120 operates according to the PWM signal (PWMS) of the controller 130. At this time, the control unit 130 generates a PWM signal (PWMS) so that the input command speed and the current speed of the motor 110 are matched, and provides it to the inverter 120.

Subsequently, when the control unit 130 receives a stop command for braking of the motor 110, the control unit 130 determines whether there is a sudden braking request together with the stop command.

Subsequently, when there is no request for sudden braking and the back EMF voltage of the motor 110 is greater than the voltage of the battery 150, the controller 130 charges the battery 150 through regenerative braking of the motor 110.

At this time, the control unit 130 controls the motor 110 to perform regenerative braking by opening the rectifier switch 107 and all switch elements included in the inverter 120. Subsequently, the controller 130 operates the first converter 140 to transfer electric energy to the battery 150 to charge the battery 150.

Subsequently, the battery 150 transfers the stored electric energy to the load 170. The battery 150 provides power to loads (eg, low-power loads) that consume less power.

In addition, when the second converter 160 does not operate normally or the power applied to the inverter 120 is in an abnormal range, the battery 150 supplies power to the load 170 instead of the second converter 160. Can provide.

In the present invention, the total amount of power used by the motor driving device 1 may be reduced by the amount of power provided by the battery 150.

Referring to FIG. 6, it can be seen that in a washing machine in which the motor driving device 1 of the present invention is used, the command speed has a constant periodicity.

This is according to the operational characteristics of the washing machine, and for washing laundry, the motor 110 alternates in a forward direction (eg, clockwise) and a reverse direction (eg, counterclockwise) at a constant cycle.

Due to the periodicity of the motor 110, a section in which the command speed is rapidly decreased (for example, S1, S2) occurs frequently, and in a section where the command speed is rapidly decreased, the motor driving device 1 By operating by regenerative braking, electric energy may be generated and stored in the battery 150. In this way, the electric energy stored in the battery 150 may be provided to and used by another load 170 of the motor driving device 1.

In summary, as electric energy generated during the regenerative braking of the motor 110 is used for the operation of the washing machine, the total amount of power consumption of the washing machine is reduced, and energy efficiency of the washing machine may be improved.

7 is a block diagram showing a motor driving apparatus according to another embodiment of the present invention. 8 is a flowchart illustrating a method of operating a motor driving apparatus according to another exemplary embodiment of the present invention. 9 is a block diagram showing a schematic operation of a motor driving apparatus according to another embodiment of the present invention.

The motor driving apparatus 2 according to another exemplary embodiment of the present invention operates in a substantially similar manner to the motor driving apparatus 1 according to the exemplary embodiment of the present invention described above, and redundant descriptions will be omitted below. Let's focus on the differences.

Referring to FIG. 7, a motor driving apparatus 2 according to another embodiment of the present invention includes a rectifier 105, a rectifier switch 107, a capacitor 109, a motor 110, an inverter 120, and a control unit ( 130).

The rectifying unit 105 rectifies and outputs the commercial AC power supply 101. For example, the rectifier 105 may include a full bridge diode connected to four diodes, but the present invention is not limited thereto, and various modifications may be applied.

The rectifier switch 107 is disposed between the rectifier 105 and the inverter 120. The rectifier switch 107 turns on and off the power transmitted from the rectifier 105 to the inverter 120. The operation of the rectifier switch 107 is controlled by the control unit 130, and when the motor driving device 1 operates by regenerative braking or power generation braking, power transmitted to the inverter 120 may be cut off.

The inverter 120 constructs the motor 110 by using the DC voltage converted by the rectifier 105. Inverter 120 is controlled by a PWM signal (PWMS) output from the control unit 130.

The control unit 130 controls the operation of the rectifier switch 107 and the inverter 120. The controller 130 may control operations of the rectifier switch 107 and the inverter 120, respectively, using a switch on-off signal and a PWM signal (PWMS).

The capacitor 109 is connected in parallel to the input terminal of the inverter 120. That is, the DC voltage Vdc applied to the input terminal of the inverter 120 is applied to both ends of the capacitor 109.

Hereinafter, the function of the capacitor 109 in the motor driving device 2 will be described.

Referring to FIG. 8, in the motor driving apparatus 2 according to another embodiment of the present invention, the control unit 130 receives a stop command from the user (S210).

Subsequently, the control unit 130 determines whether an emergency braking request is received from the user together with the stop command (S220).

Subsequently, when the sudden braking request is not received, the controller 130 compares the magnitude of the back EMF voltage generated by the motor 110 and the voltage of the capacitor 109 (S230).

Subsequently, when the back EMF voltage of the motor 110 is greater than the voltage of the capacitor 109, the control unit 130 opens the rectifier switch 107 (S240).

Through this, the motor 110 performs regenerative braking (S250). When the motor 110 performs regenerative braking, the electric energy generated from the motor 110 is transferred to the capacitor 109 through the inverter 120 and stored.

At this time, each switching element (eg, IGBT element) included in the inverter 120 includes a diode (see FIG. 3) that controls the flow of current due to back electromotive force, so it is generated during regenerative braking in the motor 110 The resulting current can be transferred to the capacitor 109.

Subsequently, the electric energy stored in the capacitor 109 is provided to the input terminal of the inverter 120 when the motor 110 is restarted. This makes it possible to additionally secure an electromotive force required at the beginning of driving the motor 110, so that even if frequent braking occurs in the motor 110, the speed before braking can be quickly restored.

Further, the electric energy charged in the capacitor 109 may allow a stable voltage to be applied to the input terminal of the inverter 120 even when an unstable power is applied to the inverter 120. This may perform a fail safe function of allowing the motor 110 to operate normally even when an unstable power is temporarily input to the motor driving device 2.

On the other hand, when a sudden braking request is received from the user along with a stop command to the control unit 130, or when the back EMF voltage of the motor 110 is less than the voltage of the capacitor 109, the motor 110 generates and brakes (S260).

When the motor 110 powers braking, the control unit 130 opens all of the first to third upper arm switches Sa, Sb, and Sc of the inverter 120, and the first to third lower arm switches S'a , S'b, S'b) are all shorted. Through this, a closed path for a three-phase coil is formed between the inverter 120 and the motor 110. At this time, a current flows through the motor 110 by the change of the magnetic flux of the motor 110 and the formation of a path of each coil, and a braking force opposite to the rotation direction of the rotor is generated by the current flowing through the coil, so that the motor 110 ) Suddenly brakes.

Referring to FIG. 9, when the motor 110 operates normally, the rectifier switch 107 is short-circuited, and the inverter 120 operates according to the PWM signal (PWMS) of the controller 130. At this time, the control unit 130 generates a PWM signal (PWMS) so that the input command speed and the current speed of the motor 110 are matched, and provides it to the inverter 120.

Subsequently, when the control unit 130 receives a stop command for braking of the motor 110, the control unit 130 determines whether there is a sudden braking request together with the stop command.

Subsequently, when there is no request for sudden braking and the back EMF voltage of the motor 110 is greater than the voltage of the capacitor 109, the controller 130 charges the capacitor 109 through regenerative braking of the motor 110.

At this time, the control unit 130 opens the rectifier switch 107 so that the motor 110 performs regenerative braking and charges the capacitor 109 with electric energy.

Subsequently, when the motor 110 starts to operate again, the electric energy stored in the capacitor 109 is used to additionally secure an electromotive force required for the initial driving of the motor 110.

Through this, the motor 110 additionally secures an electromotive force required at the beginning of driving, so that even if frequent braking occurs, the speed before braking can be quickly restored.

In summary, the motor driving apparatus according to some embodiments of the present invention frequently exhibits alternating forward and reverse directions due to its operating characteristics, and is applied to washing machines in which a high-speed motor is used recently, thereby maximizing the effect through regenerative braking of the motor. I can.

In addition, the motor driving apparatus according to some embodiments of the present invention stores energy generated through regenerative braking from a motor of a washing machine with frequent braking intervals and a large amount of speed change per hour, thereby reducing the total amount of power consumption of the washing machine. And it can improve the energy efficiency of the washing machine.

This can improve product sales in line with the recent trend of preferring low-power products, and can lead to optimal operating efficiency without significantly improving product unit cost.

The above-described present invention is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those of ordinary skill in the technical field to which the present invention belongs. Is not limited by

101: commercial AC power supply 105: rectifier
110: motor 120: inverter
130: control unit

Claims (12)

In the motor drive device of the washing machine,
A rectifier converting an AC voltage into a DC voltage;
An inverter driving the motor by applying the converted DC voltage to the motor;
A rectifier switch disposed between the rectifier and the inverter;
A control unit for controlling an operation of the rectifying unit switch and a switching element included in the inverter; And
Including a battery for storing electrical energy generated from the motor,
The control unit,
Identifying a back EMF voltage generated in the motor driven by the DC voltage applied to the motor,
Identify the voltage of the battery,
When the back EMF voltage generated by the motor is greater than the voltage of the battery, all of the first to third upper arm switch elements and the first to third lower arm switching elements included in the rectifier switch and the inverter are opened, and
Based on the opening of the first to third upper arm switch elements and the first to third lower arm switch elements, the back electromotive force voltage generated by the motor is set to be stored in the battery as the electric energy
Motor-drive unit.
delete The method of claim 1,
Further comprising an SMPS converter providing a voltage applied to the inverter to the load,
When the SMPS converter is turned off, the battery provides the stored electrical energy to the load.
Motor-drive unit.
The method of claim 1,
The motor includes a stator in which a three-phase coil is wound, and a rotor disposed in the stator and rotating by a magnetic field generated from the three-phase coil,
The inverter includes three-phase switch elements that operate on and off to supply or cut off a three-phase AC voltage to the three-phase coil.
Motor-drive unit.
The method of claim 4,
The three-phase coil,
A first phase coil supplied with a first phase AC voltage among the three phase AC voltages, a second phase coil supplied with a second phase AC voltage among the three phase AC voltages, and a third phase AC voltage among the three phase AC voltages It includes a third phase coil to which voltage is supplied,
The three-phase switch elements,
The first phase arm switch and the first lower arm switch connected in parallel with the first phase coil and operated on and off to supply the first phase AC voltage,
The second phase arm switch and the second lower arm switch connected in parallel with the second phase coil and operated on and off to supply the second phase AC voltage,
On and off operations to supply the third phase AC voltage, including the third phase arm switch and the third lower arm switch connected in parallel with the third phase coil
Motor-drive unit.
delete The method of claim 5,
The control unit, when receiving a sudden braking request for the motor, opens the first to third upper arm switches and short-circuits the first to third lower arm switches to generate and brake the motor.
Motor-drive unit.
The method of claim 4,
Further comprising a converter disposed between the motor and the battery, and converting the three-phase AC voltage output from the motor into a DC voltage and providing it to the battery.
Motor-drive unit.
In the motor drive device of the washing machine,
A rectifier converting an AC voltage into a DC voltage;
An inverter driving the motor by applying the converted DC voltage to the motor;
A rectifier switch disposed between the rectifier and the inverter;
A capacitor connected in parallel to the input terminal of the inverter and storing electric energy generated from the motor; And
The rectifier switch and a control unit for controlling the operation of the switching element included in the inverter,
The control unit,
Identifying a back EMF voltage generated in the motor driven by the DC voltage applied to the motor,
Identify the voltage of the capacitor,
When the back EMF voltage generated by the motor is greater than the voltage of the capacitor, the rectifier switch is opened,
Set to store the back EMF voltage generated by the motor as the electric energy in the capacitor
Motor-drive unit.
The method of claim 9,
The inverter includes three-phase switch elements that operate on and off to supply or cut off a three-phase AC voltage with a three-phase coil,
The three-phase coil,
A first phase coil supplied with a first phase AC voltage among the three phase AC voltages, a second phase coil supplied with a second phase AC voltage among the three phase AC voltages, and a third phase AC voltage among the three phase AC voltages It includes a third phase coil to which voltage is supplied,
The three-phase switch elements,
A first phase arm switch and a first lower arm switch connected in parallel with the first phase coil and operated on and off so that the first phase AC voltage is supplied,
A second upper arm switch and a second lower arm switch connected in parallel with the second phase coil and operated on and off to supply the second phase AC voltage,
Operating on and off to supply the third phase AC voltage, including a third phase arm switch and a third lower arm switch connected in parallel with the third phase coil
Motor-drive unit.
delete The method of claim 10,
The control unit, when receiving a sudden braking request to the motor, opens the first to third upper arm switches and short-circuits the first to third lower arm switches to generate and brake the motor
Motor-drive unit.

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