KR102127840B1 - Motor driving apparatus and home appliance including the same - Google Patents

Abstract

A motor driving apparatus and a home appliance having the same according to an embodiment of the present invention include a dc stage capacitor and a plurality of switching elements, and by switching operations of the plurality of switching elements, the DC power of the dc stage capacitor is converted into an AC power. An inverter that converts and outputs the converted AC power to the motor, an output current detection unit disposed between the dc terminal capacitor and the inverter to detect the current, and an inverter control unit that controls the inverter based on the current detected through the output current detection unit Including, the inverter control unit, by controlling the pulse width variable control based on a space vector, controls the plurality of switching elements, and detects the first phase current and the second phase current among the three phase currents in the first half cycle of the switched cycle. Generates two or more effective vectors to drive the inverter, and generates an effective vector for detection that detects a third phase current that is not detected during the first half cycle from the second half cycle, which is the next half cycle of the first half cycle, to drive the inverter can do.

Description

Motor driving apparatus and home appliance including the same}

The present invention relates to a motor drive device and a home appliance having the same, and more particularly, to a motor drive device capable of accurately detecting a phase current and a home appliance having the same.

A home appliance is a device used for user convenience.

In addition, home appliances, such as clothes dryers, washing machines, refrigerators, and air conditioners used in the home, each perform unique functions and operations according to user manipulation.

On the other hand, the motor driving device is a device for driving a motor having a rotor and a stator wound with a coil, which rotates, and may be used to drive a motor in a home appliance.

Recently, a sensorless motor driving device is frequently used for reasons such as reduction in manufacturing cost, and accordingly, a research on a sensorless motor driving device has been conducted for efficient motor driving.

In order to stably drive the sensorless motor driving apparatus, a method capable of detecting the phase current simply and accurately is required.

For example, the prior document 1 (Korean Patent Publication No. 10-2011-0014438, published date February 11, 2011) is a circuit for detecting the inverter output current using a plurality of resistance elements connected to the switching element of the inverter It describes the contents of.

Recently, circuits for sensing the output current of the inverter using one resistance element have been proposed. These circuits estimate a specific phase current on the premise that the sum of the three phase currents is zero. However, an error occurs when the sum of the three-phase currents is not 0 due to leakage current or the like.

Accordingly, there is a need for a method capable of easily and accurately detecting a phase current at a low cost and correcting an error when sensing an inverter output current using one resistance element.

An object of the present invention is to provide a motor drive device capable of accurately detecting a phase current flowing in a motor and a home appliance having the same.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor driving device capable of stably driving a motor by correcting a current error due to the influence of leakage current, and a home appliance having the same.

A motor driving apparatus and a home appliance having the same according to an embodiment of the present invention for achieving the above object include a dc stage capacitor and a plurality of switching elements, and by switching operations of the plurality of switching elements, the dc stage capacitor On the basis of the current detected through the output current detection unit for converting a DC power supply to an AC power supply, and outputting the converted AC power to the motor, a dc stage capacitor and an inverter disposed to detect the current, and an output current detection unit, Including an inverter control unit for controlling the inverter, the inverter control unit controls the plurality of switching elements by a space vector-based pulse width control, the first phase current of the three-phase current in the first half cycle of the switching cycle Generates two or more valid vectors for detecting the second phase current, drives the inverter, and detects a valid vector for detecting a third phase current that is not detected during the first half cycle from the second half cycle, which is the next half cycle of the first half cycle. By generating, it is possible to drive the inverter.

According to at least one of the embodiments of the present invention, it is possible to accurately detect the phase current flowing through the motor.

In addition, according to at least one of the embodiments of the present invention, it is possible to stably drive the motor by correcting a current error due to the influence of leakage current or the like.

Meanwhile, various other effects will be disclosed directly or implicitly in a detailed description according to an embodiment of the present invention to be described later.

1 is an example of an internal block diagram of a motor drive device according to an embodiment of the present invention.
FIG. 2 is an example of an internal circuit diagram of the motor driving apparatus of FIG. 1.
3 is an internal block diagram of the inverter control unit of FIG. 2.
4 is a diagram illustrating an output current detection unit of a motor driving apparatus according to an embodiment of the present invention.
5 is a diagram illustrating a voltage vector based on a space vector according to a switching combination of each switching element in an inverter.
6A to 6C are diagrams referenced to describe a current estimation technique.
7 is a diagram illustrating switching of each switching element in a voltage vector and an inverter according to an embodiment of the present invention.
8A to 8E are diagrams illustrating switching of each switching element in an inverter corresponding to a voltage vector according to an embodiment of the present invention.
9 is a diagram illustrating a voltage vector according to an embodiment of the present invention.
10A to 10D are diagrams illustrating switching of each switching element in an inverter corresponding to a voltage vector according to an embodiment of the present invention.
11 is a view referred to for a description of current compensation according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it should be understood that the present invention is not limited to these embodiments and can be modified in various forms.

In the drawings, in order to clearly and briefly describe the present invention, illustration of parts irrelevant to the description is omitted, and the same reference numerals are used for the same or extremely similar parts throughout the specification.

On the other hand, the suffixes "module" and "part" for the components used in the following description are given merely considering the ease of writing the present specification, and do not impart a particularly important meaning or role in itself. Therefore, the "module" and the "unit" may be used interchangeably.

Further, in the present specification, terms such as first and second may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

The motor driving device 220 described in this specification, such as a hall sensor that detects the position of the rotor of the motor, does not have a sensing unit, by a sensorless method, the position of the rotor of the motor It is a motor driving device that can estimate. Hereinafter, a sensorless motor driving device will be described. Meanwhile, the motor driving apparatus 220 according to the embodiment of the present invention may be referred to as a motor driving unit.

1 is an example of an internal block diagram of a motor driving apparatus according to an embodiment of the present invention, and FIG. 2 is an example of an internal circuit diagram of a motor driving apparatus of FIG. 1.

Referring to the drawings, the motor driving apparatus 220 according to an embodiment of the present invention is for driving a motor in a sensorless manner, and may include an inverter 420 and an inverter control unit 430.

In addition, the motor driving apparatus 220 according to an embodiment of the present invention may further include a converter 410 that converts input AC power to DC power and outputs it.

In addition, the motor driving apparatus 220 according to an embodiment of the present invention, the input current detector (A), reactor (L), dc stage capacitor (C), dc stage voltage detector (B), output current detector (E) It may further include.

Meanwhile, the inverter controller 430 according to an embodiment of the present invention may control a switching element in the inverter 420 by variable control of a space vector-based pulse width modulation (PWM).

The motor driving apparatus 220 according to an embodiment of the present invention may further include an output current detector (see Edc in FIG. 4) disposed between the dc terminal capacitor C and the inverter 420. For example, the motor driving apparatus 220 according to an embodiment of the present invention further includes one dc stage resistor element (see Rdc in FIG. 4) disposed between the dc stage capacitor C and the inverter 420. It may include, such a dc terminal resistance element may be referred to as a shunt (shunt) resistance element.

At this time, the inverter control unit 430 controls the switching element in the inverter 420 by controlling the space vector-based pulse width.

To this end, the inverter controller 430 receives phase current information that is sequentially detected using one dc terminal resistance element, and based on this, the inverter 420 by a space vector based pulse width variable control. Switching element within can be controlled.

On the other hand, it is assumed that the sum of three phase currents is 0 when sequentially detecting phase currents using one dc terminal resistance element. However, an error occurs when the sum of the three-phase currents is not 0 due to the influence of the leakage current due to the parasitic capacitance component.

In order to detect the current error due to the influence of leakage current, the motor driving apparatus 220 according to the embodiment of the present invention includes a dc stage capacitor (C) and a plurality of switching elements, and switching of the plurality of switching elements By operation, the DC power of the DC terminal capacitor (C) is converted to an AC power, and the inverter 420 outputs the converted AC power to the motor, and is disposed between the DC terminal capacitor (C) and the inverter 420 current It may include an output current detection unit (Edc) for detecting, and an inverter control unit 430 for controlling the inverter 420 based on the current detected through the output current detection unit (Edc).

The inverter control unit 430 may control the plurality of switching elements in the inverter 420 by controlling the spatial vector-based pulse width.

When one switching period is composed of the first half period and the second half period, the inverter control unit 430 according to an embodiment of the present invention performs the inverter 420 with a PWM pattern different from the first half period in the second half period. Can be controlled.

The inverter control unit 430 according to an embodiment of the present invention generates two or more effective vectors for detecting the first phase current and the second phase current among the three phase currents in the first half cycle of the switching cycle, and the inverter 420 Can drive.

In addition, the inverter control unit 430 may generate an effective vector for detecting a third phase current that is not detected during the first half period from the second half period, which is the next half period of the first half period, to drive the inverter 420. have.

Accordingly, rather than estimating one or more phase currents on the premise that the sum of the three phase currents is zero, all three phase currents can be directly detected, thereby accurately detecting the phase current flowing in the motor 230.

In addition, the output current detector (Edc), by using a single dc stage resistor element (Rdc), time-division, by detecting the phase current, the manufacturing cost is reduced, there is an advantage that the installation is easy.

Hereinafter, the operation of each of the constituent units in the motor drive device 220 of FIGS. 1 and 2 will be described.

The reactor L is disposed between the input AC power source 405 and the converter 410 to perform power factor correction or boost operation. In addition, the reactor L may perform a function of limiting harmonic currents due to high-speed switching of the converter 410 or the like.

The input current detector A can detect the input current is input from the commercial AC power supply 405. To this end, as the input current detector A, a current transformer (CT), a shunt resistor, or the like can be used. The detected input current is may be input to the inverter control unit 430 as a pulsed discrete signal.

The converter 410 converts the commercial AC power 405 that has passed through the reactor L into a DC power and outputs it to the DC terminal. Although the commercial AC power source 405 is illustrated as a single-phase AC power source in the drawing, it may be a three-phase AC power source. The internal structure of the converter 410 may also vary according to the type of the commercial AC power source 405.

Meanwhile, the converter 410 may be made of a diode or the like without a switching element, and may perform a rectification operation without a separate switching operation.

For example, in the case of a single-phase AC power supply, four diodes may be used in the form of a bridge, and in the case of a three-phase AC power supply, six diodes may be used in the form of a bridge.

Meanwhile, as the converter 410, for example, a half-bridge type converter in which two switching elements and four diodes are connected may be used, and in the case of a three-phase AC power source, six switching elements and six diodes may be used. . In this case, the converter 410 may be referred to as a rectifier.

When the converter 410 includes a switching element, a step-up operation, power factor improvement, and DC power conversion may be performed by a switching operation of the switching element.

The dc terminal capacitor (C) is connected to both ends of the dc, and smooths the input power and stores it. In the drawing, one device is illustrated as a dc terminal capacitor (C), but a plurality of devices are provided to secure device stability.

On the other hand, in the drawing, it is exemplified as being connected to the output terminal of the converter 410, but is not limited thereto, and DC power may be directly input. For example, DC power from a solar cell may be directly input to a DC terminal capacitor C or DC/DC conversion may be input. Hereinafter, parts illustrated in the drawings are mainly described.

On the other hand, since both ends of the dc terminal capacitor (C), DC power is stored, it may also be referred to as a dc terminal or a dc link terminal.

The dc stage voltage detector B may detect the dc stage voltage Vdc that is both ends of the dc stage capacitor C. To this end, the dc stage voltage detector B may include a resistance element, an amplifier, and the like. The detected dc stage voltage (Vdc) may be input to the inverter control unit 430 as a pulsed discrete signal.

The inverter 420 includes a plurality of inverter switching elements, and converts the DC power supply (Vdc) smoothed by the on/off operation of the switching element into three-phase AC power (va, vb, vc) of a predetermined frequency, thereby three-phase It can be output to the synchronous motor 230.

In the inverter 420, the upper and lower switching elements Sa, Sb and Sc, and the lower and lower switching elements S'a, S'b and S'c are connected in series with each other, and a total of three pairs of upper and lower arms The switching elements are connected in parallel to each other (Sa&S'a,Sb&S'b,Sc&S'c). A diode is connected in reverse parallel to each of the switching elements Sa, S'a, Sb, S'b, Sc, and S'c.

The switching elements in the inverter 420 operate on/off of each switching element based on the inverter switching control signal Sic from the inverter control unit 430. Thereby, the three-phase AC power having a predetermined frequency is output to the three-phase synchronous motor 230.

The inverter control unit 430 may control the switching operation of the inverter 420 based on the sensorless method. To this end, the inverter control unit 430 may receive the output current io detected by the output current detection unit E.

In order to control the switching operation of the inverter 420, the inverter control unit 430 outputs the inverter switching control signal Sic to the inverter 420. The inverter switching control signal Sic is a pulse width modulation type (PWM) switching control signal, which is generated and output based on the output current io detected by the output current detection unit E.

The output current detector E detects the output current io flowing between the inverter 420 and the three-phase motor 230. That is, the current flowing through the motor 230 is detected. The output current detector E may detect all the output currents ia, ib, and ic of each phase, or may detect the output currents of two phases using three-phase balance.

The output current detector E may be located between the inverter 420 and the motor 230, and a current trnasformer (CT), shunt resistor, or the like may be used for current detection.

When a shunt resistor is used, three shunt resistors are located between the inverter 420 and the synchronous motor 230, or three lower arm switching element elements S'a, S'b, S'c of the inverter 420 It is possible that each end is connected to ).

Alternatively, two shunt resistors are used, and it is also possible to calculate the current of the other phase using three-phase equilibrium.

More preferably, one shunt resistor may be disposed between the dc terminal capacitor C and the inverter 420. This method can be referred to as a 1-shunt method.

According to the one shunt method, the output current detector E flows through the motor 230 when the turn-on of the lower arm switching element of the inverter 420 is turned on by using one shunt resistor element (Rdc in FIG. 4). The phase current, which is the output current io, can be detected.

The detected output current io may be applied to the inverter control unit 430 as a pulsed discrete signal, and the inverter switching control signal Sic is generated based on the detected output current io. do. Hereinafter, it may be described in parallel that the detected output current (io) is a three-phase output current (ia, ib, ic).

Meanwhile, the three-phase motor 230 includes a stator and a rotor, and AC power of a predetermined frequency is applied to a coil of the stator of each phase (a, b, and c), so that the rotor rotates. Will do.

Such a motor 230 is, for example, a surface-mounted permanent magnet synchronous motor (Surface-Mounted Permanent-Magnet Synchronous Motor; SMPMSM), an embedded permanent magnet synchronous motor (Interidcr Permanent Magnet Synchronous Motor; IPMSM), and a synchronous reel And a Synchronous Reluctance Motor (Synrm). Among them, SMPMSM and IPMSM are Permanent Magnet Synchronous Motor (PMSM) with permanent magnet applied, and Synrm has no permanent magnet.

The load 231 is for performing an operation implemented in the home appliance 100 and may be configured differently for each home appliance 100.

For example, when the clothes dryer includes the motor driving device 220, the load 231 may be a blower fan for supplying compressed air.

As another example, when the air conditioner includes the motor driving device 220, the load 231 may be an indoor fan, an outdoor fan, or a compressor that compresses refrigerant.

As another example, when the refrigerator includes the motor driving device 220, the load 231 may be a refrigerator compartment fan or a freezer compartment fan.

3 is an internal block diagram of the inverter control unit of FIG. 2.

Referring to the drawings, the inverter control unit 430, the axis conversion unit 310, the speed calculation unit 320, the current command generation unit 330, the voltage command generation unit 340, the axis conversion unit 350, And it may include a switching control signal output unit 360.

The axis conversion unit 310 may convert the output currents ia, ib, and ic detected by the output current detection unit E into two-phase currents iα and iβ in the stationary coordinate system.

Meanwhile, the axis converter 310 may convert the two-phase currents iα and iβ of the stationary coordinate system into two-phase currents id and iq of the rotary coordinate system.

)를 추정하고, 추정된 위치를 미분하여, 속도(

)를 연산할 수 있다. The speed calculation unit 320 is based on the output current (ia, ib, ic) detected by the output current detection unit (E), the position value (

), differentiate the estimated position,

).

)와 속도 지령치(ω^* _r)에 기초하여, 전류 지령치(i^* _q)를 생성한다. 예를 들어, 전류 지령 생성부(330)는, 연산 속도(

)와 속도 지령치(ω^* _r)의 차이에 기초하여, PI 제어기(335)에서 PI 제어를 수행하며, 전류 지령치(i^* _q)를 생성할 수 있다. 도면에서는, 전류 지령치로, q축 전류 지령치(i^* _q)를 예시하나, 도면과 달리, d축 전류 지령치(i^* _d)를 함께 생성하는 것도 가능하다. 한편, d축 전류 지령치(i^* _d)의 값은 0으로 설정될 수도 있다. On the other hand, the current command generation unit 330, the calculation speed (

) And the current command value (i ^* _q ) is generated based on the speed command value (ω ^* _r ). For example, the current command generation unit 330, the calculation speed (

) And the speed command value (ω ^* _r ), the PI controller 335 performs PI control and generates a current command value (i ^* _q ). In the drawing, as the current command value, the q-axis current command value (i ^* _q ) is illustrated, but unlike the drawing, it is also possible to generate the d-axis current command value (i ^* _d ) together. Meanwhile, the value of the d-axis current command value (i ^* _d ) may be set to 0.

Meanwhile, the current command generation unit 330 may further include a limiter (not shown) that limits the level so that the current command value i ^* _q does not exceed the allowable range.

Next, the voltage command generation unit 340, the d-axis, q-axis current (i _d ,i _q ) axis-converted to the two-phase rotation coordinate system in the axis conversion unit, the current command value in the current command generation unit 330, etc. Based on i ^* _d ,i ^* _q ), the d-axis and q-axis voltage command values (v ^* _d ,v ^* _q ) are generated. For example, the voltage command generation unit 340 performs PI control in the PI controller 344 based on the difference between the q-axis current i _q and the q-axis current command value i ^* _q , q The axial voltage setpoint (v ^* _q ) can be generated. In addition, the voltage command generation unit 340 performs PI control in the PI controller 348 based on the difference between the d-axis current i _d and the d-axis current command value i ^* _d , and the d-axis voltage The setpoint (v ^* _d ) can be generated. Meanwhile, the voltage command generation unit 340 may further include a limiter (not shown) that limits the level so that the d-axis and q-axis voltage command values (v ^* _d , v ^* _q ) do not exceed the allowable range. .

Meanwhile, the generated d-axis and q-axis voltage command values (v ^* _d , v ^* _q ) are input to the axis conversion unit 350.

)와, d축, q축 전압 지령치(v^* _d,v^* _q)를 입력받아, 축변환을 수행한다.The axis conversion unit 350, the position calculated by the speed calculation unit 320 (

), d-axis, and q-axis voltage command values (v ^* _d , v ^* _q ) are input and axis conversion is performed.

)가 사용될 수 있다.First, the axis conversion unit 350 performs conversion from a two-phase rotational coordinate system to a two-phase stationary coordinate system. At this time, the position calculated by the speed calculation unit 320 (

) Can be used.

Then, the axis conversion unit 350 performs conversion from a two-phase stationary coordinate system to a three-phase stationary coordinate system. Through this conversion, the axis conversion unit 1050 outputs a three-phase output voltage command value (v ^* a, v ^* b, v ^* c).

The switching control signal output unit 360 generates a switching control signal (Sic) for an inverter according to a pulse width modulation (PWM) method based on a three-phase output voltage command value (v ^* a, v ^* b, v ^* c). And output.

The output inverter switching control signal Sic may be converted into a gate driving signal by a gate driving unit (not shown), and input to the gate of each switching element in the inverter 420. Accordingly, each of the switching elements Sa, S'a, Sb, S'b, Sc, and S'c in the inverter 420 performs a switching operation.

On the other hand, the motor driving device 220, through the control of the inverter 420, in order to perform a vector (vector) control for driving the motor 230, to detect the output current flowing in the motor 230, in particular, the phase current Can.

The inverter control unit 430 may control the motor 230 to a desired speed and torque through the current command generation unit 330 and the voltage command generation unit 340 using the sensed phase current. do.

4 is a diagram illustrating an output current detection unit of a motor driving apparatus according to an embodiment of the present invention.

Referring to the drawings, the output current detector E may include a shunt resistor element Rdc disposed between the dc terminal capacitor C and the inverter 420.

The inverter control unit 430 may sense the current flowing through the motor 230 based on the current flowing through the dc terminal resistance element Rdc, and control the inverter 420 based on the sensed motor current.

As shown in the figure, a current acquisition method using a shunt resistor element Rdc is called a shunt algorithm.

The shunt algorithm is divided into 1-shunt, 2-shunt, and 3-shunt according to the position and number of shunt resistor elements. The motor-drive unit 220 of the present invention may use a 1-shunt method. Hereinafter, a 1-shunt method will be described.

According to this one-shunt (shunt) method, the three-phase current (a,b,c-phase current) flowing in the motor 230 is obtained with only one shunt resistor element disposed in the dc stage.

Therefore, it is possible to sense the phase current without a current sensor, and it is possible to reduce peripheral circuits such as a voltage amplifier and an A/D port as compared to a two-shunt and three-shunt method. In addition, there are many advantages, such as a reduction in manufacturing cost and volume of the motor driving device 220.

The motor driving device 220 may detect a phase current using one shunt resistor element Rdc. In this case, the inverter control unit 430 may control the switching element in the inverter 420 by controlling the space vector-based pulse width.

5 illustrates a space vector based voltage vector according to a switching combination of each switching element in the inverter.

Referring to the drawing, when all of the upper and lower switching elements Sa, Sb, and Sc in the inverter 420 are On, it corresponds to a zero vector of V0 (111), and the lower arm switching element S' a,S'b,S'c) all correspond to the zero vector of V7(000), which is on. That is, in the spatial vector region 800, two zero vectors exist.

On the other hand, in the figure, six valid vectors V1 to V6 are illustrated.

6A to 6C are diagrams referenced to describe a current estimation technique.

More specifically, FIG. 6A is a diagram illustrating switching of each switching element in the inverter 420 corresponding to the first valid vector V1 and the second valid vector V2, and FIG. 6B is a first valid vector It is a figure which exemplifies the current path in (V1).

Referring to the drawings, according to the switching combination of each switching element in the inverter 420, a space vector-based voltage vector may be generated.

Meanwhile, a voltage vector v* may be generated by a combination of the first valid vector V1 and the second valid vector V2. The voltage vector v* may be generated by the voltage command generator (340 in FIG. 3) described above.

The 1-shunt method detects a phase current from the shunt resistor element Rdc when an effective vector is applied, in a control period Ts for a spatial vector based PWM (SVPWM), and detects the detected phase current as an analog. Digital (A/D) conversion is performed, and a gate signal generation unit (not shown) in the switching control signal output unit (360 in FIG. 3) determines a current sector and an effective vector to restore a phase current. At this time, since the vector is applied within one period Ts, the two-phase current can be restored, and the current of the other one is obtained by using the sum of the currents of the three phases as zero.

In FIG. 6A, the region S51 is a region where the first phase cancer switching element Sa is turned on, the second phase cancer switching element Sb is turned off, and the third phase cancer switching element Sc is turned off, in the first effective vector V1 region. To respond.

In FIG. 6B, the first lower arm switching element S'a, the second lower arm switching element S'b, and the third lower arm switching element S'c are connected to the respective upper and lower arm switching elements Sa, Sb and Sc. Since it operates complementarily, the input current is input through the first upper arm switching element Sa, and thus the motor 230, the second lower arm switching element S'b, and the third lower arm switching element S'c. Via, it is applied to the shunt resistor element (Rdc). In the drawing, the first current path (Path 1) is illustrated.

Therefore, the output current detection unit Edc detects a phase current ia during T2/2 time, which is the application time of the first effective vector V1.

The output current detector Edc can detect the c-phase current -ic during T1/2 time, which is the application time of the second effective vector V2, in the same manner.

The inverter control unit 430 may obtain the remaining b-phase current ib through internal calculation.

6C is a diagram illustrating a state of a motor current detected by the output current detector Edc for each vector.

Referring to the drawing, for a first effective vector in sector 1, through a shunt resistor element Rdc, an Ias current that is a phase current is detected, and for a second effective vector in sector 2, a shunt resistor element ( Rdc), the c-phase current -Ics current is detected, and for the third effective vector in sector 3, through the shunt resistor element Rdc, the b-phase current Ibs current is detected, in sector 4 For the fourth effective vector, through the shunt resistor element Rdc, a -Aas current, which is a phase current, is detected, and for the fifth effective vector in sector 5, through the shunt resistor element Rdc, the c phase current Phosphorus Ics current is detected, and for the sixth effective vector in sector 6, through the shunt resistor element Rdc, the b-phase current -Ibs current is detected.

On the other hand, for the zero vectors, V0 and V7 vectors, current detection becomes impossible through the shunt resistor element Rdc.

As described above, the conventional 1-shunt current sensing technique controls from the viewpoint that the sum of currents is zero. For example, the current of the two phases is sensed, and the current of the other one phase is calculated on the premise that ia + ib + ic = 0. That is, if ia and ib are measured, ic = -ia-ib is calculated.

However, when ia + ib + ic = 0, which is a premise for calculating the remaining phase current, is not satisfied, there is a problem that the phase current calculation value does not match. According to this phenomenon, unstable control is repeated and then diverges.

As described above, when the sum of the three phases of the current is not 0, an error is inevitably generated in the conventional 1-shunt logic, and is diverted when a neutral current is generated.

For example, when leakage occurs due to assembly tolerance of the motor, a current distortion occurs in 1-shunt, and control error and sensorless error can be increased.

The present invention can measure all three phase currents even if the sum of three phase currents is not 0 in the 1-shunt current sensing technique.

In addition, the present invention proposes a 1-Shunt vector control method for reducing errors.

According to the present invention, in the state in which an error in which the sum of the currents of the three phases does not become 0, current correction is performed so that the value of the current becomes 0.

Therefore, even if a neutral point current is generated due to a problem of the motor, it is possible to compensate for this and prevent divergence of the controller.

7 is a diagram illustrating switching of each switching element in a voltage vector and an inverter according to an embodiment of the present invention.

1 to 4, the motor driving apparatus 220 according to an embodiment of the present invention includes a dc stage capacitor C and a plurality of switching elements, and switching of the plurality of switching elements By operation, the DC power of the DC terminal capacitor (C) is converted to an AC power, and the inverter 420 outputs the converted AC power to the motor, and is disposed between the DC terminal capacitor (C) and the inverter 420 current It may include an output current detection unit (Edc) for detecting, and an inverter control unit 430 for controlling the inverter 420 based on the current detected through the output current detection unit (Edc).

Here, the output current detection unit Edc includes one resistance element Rdc to detect the current in a 1-shunt method.

Meanwhile, the inverter control unit 430 may control the plurality of switching elements in the inverter 420 by controlling the space vector-based pulse width.

7A, a first voltage vector 710, a second voltage vector 720, a third voltage vector 730, and a fourth voltage vector 740 according to an increase in the controller phase Theta in sector 1 ).

FIG. 7B illustrates switching of the switching element in one switching cycle corresponding to the third voltage vector 730.

Referring to (b) of FIG. 7, when the switching period Ts is composed of the first half period Ts1 and the second half period Ts2, the inverter control unit 430 according to an embodiment of the present invention In the second half period Ts2, the inverter 420 may be controlled by a PWM pattern different from the first half period Ts1.

The inverter control unit 430 according to an embodiment of the present invention generates two or more effective vectors for detecting the first phase current and the second phase current among the three phase currents in the first half period Ts1 of the switching period Ts. Thus, the inverter 420 can be driven.

In addition, the inverter control unit 430 generates a valid vector for detection that detects a third phase current that is not detected during the first half period Ts1 in the second half period Ts2, which is the next half period of the first half period Ts1, , Can drive the inverter 420.

For example, the phase current ic of the W phase may be detected by the second effective vector V2 110 in the first half period Ts1. Also, the U-phase current ia can be detected by the first effective vector V1 (100 ).

That is, in the example of FIG. 7B, the phase current ic of the W phase and the phase current ia of the U phase can be detected during the first half period Ts1.

However, the phase current ib of the V phase is not detected during the first half period Ts1. Conventionally, the phase current (ib) of the V phase was estimated by the phase current (ic) of the W phase and the phase current (ia) of the U phase, but the present invention generates an effective vector for detection to measure the phase current (ib) of the V phase The inverter 420 can be driven.

In the example of FIG. 7B, the phase current ib of the V phase can be detected by forcibly applying the sixth effective vector V6 (101) as the effective vector for detection in the second half period Ts2.

Alternatively, the phase current ib of the V phase may be detected by using the third valid vector V3 (010) as the effective vector for detection in the second half period Ts2.

Normally, the control is performed symmetrically based on the midpoint within one switching period (Ts), but the present invention forcibly applies an effective vector for detection to detect the phase current of the other one phase, so that the three-phase within the switching period (Ts) All currents can be detected.

The present invention does not estimate one or more phase currents on the premise that the sum of the three phase currents is zero, but can directly detect all three phase currents, thereby accurately detecting the phase current flowing through the motor 230.

Meanwhile, the valid vector for detection may be the last valid vector among the valid vectors of the second half period Ts2. In the example of FIG. 6B, the sixth valid vector V6(101) may be the last valid vector, and the zero vector may be applied after the sixth valid vector V6(101).

Also, the effective vector for detection may be applied to the inverter 420 only once in a predetermined sector. Further, the effective vector for detection may be applied shorter than other effective vector application times. That is, the application time of the effective vector for detection may be the shortest within one switching period (Ts).

Accordingly, it is possible to minimize the phenomenon that the voltage vector is distorted instantaneously, electrical noise, and the like.

Meanwhile, the inverter control unit 430 may determine that there is a current error when a value calculated by summing the detected first phase current, second phase current, and third phase current is not zero.

Ideally, the sum of the three-phase currents should be balanced to be zero. However, if the sum of three-phase currents does not become 0 due to leakage current due to parasitic capacitance components, the inverter control unit 430 may determine that a current error exists.

In addition, the inverter control unit 430 may estimate the current error by summing the detected first phase current, second phase current, and third phase current.

That is, ia + ib + ic = ierror (current error). If ia + ib + ic = 0, ierror (current error) is 0 and no current error has occurred.

Meanwhile, the inverter control unit 430 may perform current compensation to cancel the estimated current error (ierror).

According to an embodiment, the inverter control unit 430 may accumulate and store the estimated current error. Even in this case, the inverter control unit 430 may perform current compensation using the accumulated current error.

On the other hand, as described with reference to Figure 3, the inverter control unit 430 based on the current detected through the output current detection unit (Edc), the speed calculation unit 320 for calculating the rotor speed of the motor 230 , A current command generator 330 for generating a current command value based on the calculated speed information and the speed command value, and a voltage command generator 340 for generating a voltage command value based on the current command value and the detected current ), and a switching control signal output unit 360 outputting a switching control signal for driving the inverter 420 based on the voltage command value.

When a leakage occurs due to assembly tolerance of the motor 230, a current distortion occurs in 1-shunt, and a controller error and a sensorless error can be increased.

Meanwhile, the controller may be a current controller. Here, the current controller may be a voltage command generator 340. In some cases, the current controller may be a concept that further includes a current command generator 330.

The inverter control unit 430 according to the present invention forcibly applies an effective vector for detecting all three phases in order to detect a leakage current in the middle of a general 1-shunt logic.

The inverter control unit 430 accumulates the detected errors at this time, and may compensate by synchronizing with the current phase.

The present invention has an advantage in that when a neutral point current is generated, a control error is corrected and robust control against leakage by a motor is possible. Therefore, it is possible to correct the error due to the tolerance of the motor or aging and operate the motor stably.

8A to 8E are diagrams illustrating switching of each switching element in an inverter corresponding to a voltage vector according to an embodiment of the present invention, FIG. 8A corresponds to a first voltage vector 710, and FIG. 2 corresponds to the voltage vector 720, FIG. 8C corresponds to the third voltage vector 730, and FIG. 8D corresponds to the fourth voltage vector 740.

According to the present invention, it is possible to detect all three-phase currents in a predetermined voltage vector.

8A to 8D, the phase current ib of V phase can be detected using the third voltage vector 730 of sector 1.

In the first voltage vector 710, the second voltage vector 720, and the fourth voltage vector 740, the phase current ic of the W phase and the phase current ia of the U phase can be detected. However, the phase current ib of V phase is not detected in the first voltage vector 710, the second voltage vector 720, and the fourth voltage vector 740.

In addition, the third voltage vector 730 also detects the phase current ic of the W phase with the second effective vector V2(110) during the first half period Ts1, and the first effective vector V1(100). The phase current ia of the U phase can be detected.

The phase current ib of the V phase is not detected during the first half period Ts1 of the third voltage vector 730, but the sixth effective vector V6 (101) is used as the effective vector for detection in the second half period Ts2. It can be used to detect the phase current ib of the V phase.

On the other hand, it is not preferable to apply the effective vector for detection every switching cycle, and it is preferable to apply once in one sector as shown in FIGS. 8A to 8D.

8E illustrates another valid vector for detection of sector 1. Referring to FIG. 8E, the phase current ib of the V phase can be detected using the third valid vector V3(010) as the effective vector for detection.

The inverter control unit 430 according to the present invention may output a PWM capable of detecting all three-phase currents by changing the PWM pattern during vector control.

In addition, the inverter control unit 430 according to the present invention can detect the imbalance of the three-phase current with such PWM, and accumulate and store it.

In addition, the inverter control unit 430 according to the present invention can compensate by synchronizing the stored error component to the phase of the output.

9 is a diagram illustrating a voltage vector according to an embodiment of the present invention, and FIGS. 10A to 10D are diagrams illustrating switching of each switching element in an inverter corresponding to the voltage vector according to an embodiment of the present invention .

9 illustrates a first voltage vector 910, a second voltage vector 920, a third voltage vector 930, and a fourth voltage vector 940 as the controller phase Theta increases in sector 2. .

FIG. 10A corresponds to the first voltage vector 910, FIG. 10B corresponds to the second voltage vector 920, FIG. 10C corresponds to the third voltage vector 930, and FIG. 10D shows the fourth voltage vector ( 940).

9 and 10A to 10D, it is possible to detect the phase current ia of the U phase using the third voltage vector 930 of sector 2.

In the first voltage vector 910, the second voltage vector 920, and the fourth voltage vector 940, the phase current ic of W phase and the phase current ib of V phase can be detected. However, in the first voltage vector 910, the second voltage vector 920, and the fourth voltage vector 940, the U phase phase current ia is not detected.

Also, in the third voltage vector 930, the phase current ic of the W phase is detected by the second effective vector V2 (110) during the first half period Ts1, and the third effective vector V3 (010) is used. The phase current ib of the V phase can be detected.

The phase current ia of the U phase is not detected during the first half period Ts1 of the third voltage vector 930, but the fourth effective vector V4 (011) is used as the effective vector for detection in the second half period Ts2. Can be used to detect the phase current ia of the U phase.

On the other hand, it is not preferable to apply the effective vector for detection every switching period, and it is preferable to apply once in one sector as shown in FIGS. 10A to 10D.

11 is a view referred to for a description of current compensation according to an embodiment of the present invention.

11(a) shows an example of the controller phase (Theta), FIG. 11(b) illustrates the sensed current error (ierror), and FIG. 11(c) shows the current error (ierror). The corresponding compensation current is illustrated.

As shown in (a) of FIG. 11, as the controller phase (Theta) changes, the inverter control unit 140 may start operation with the existing 1-Shunt control logic.

However, the inverter control unit 140 outputs a valid vector for detection capable of detecting all three phases when the sector 1 is an intermediate point between the first valid vector and the second valid vector.

That is, the inverter control unit 140 may detect the two-phase current according to the existing 1-Shunt control logic, and output a valid vector for detection to detect the remaining phase current among the three phases.

Accordingly, all phase currents can be detected, and three-phase imbalance can be detected. As shown in (b) of FIG. 11, the three-phase imbalance can be represented by an current error (ierror).

Meanwhile, the inverter control unit 140 may correct the current error by interpolating an error detected as a compensation current corresponding to the current error (ierror) as shown in FIG.

The motor driving apparatus and the home appliance having the same according to the present invention are not limited to the configuration and method of the above-described embodiments, and the above embodiments are all of the embodiments so that various modifications can be made. Alternatively, a part may be selectively combined and configured.

In addition, although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention pertains without departing from the gist of the present invention claimed in the claims. In addition, various modifications can be implemented by those skilled in the art, and these modifications should not be individually understood from the technical idea or prospect of the present invention.

220: motor drive
230: motor
231: load
410: converter
420: inverter
430: inverter control

Claims (9)

dc stage capacitor;
An inverter which includes a plurality of switching elements, converts the DC power of the dc terminal capacitor into AC power by the switching operation of the plurality of switching elements, and outputs the converted AC power to the motor;
An output current detector arranged between the dc terminal capacitor and the inverter to detect current; And
Includes; an inverter control unit for controlling the inverter, based on the current detected through the output current detection unit,
The inverter control unit,
By controlling the space vector-based pulse width variable control, the plurality of switching elements are controlled,
In the first half cycle of the switching cycle, two or more effective vectors for detecting the first phase current and the second phase current among the three phase currents are generated to drive the inverter,
In the second half cycle, which is the next half cycle of the first half cycle, an effective vector for detecting a third phase current that is not detected during the first half cycle is generated to drive the inverter,
The current error is estimated by summing the detected first phase current, second phase current, and third phase current,
And a motor compensation device that compensates for the estimated current error. According to claim 1,
The output current detection unit, a motor drive device characterized in that it comprises a single resistance element. According to claim 1,
The effective vector for detection,
And a last valid vector among the valid vectors of the second half period. According to claim 1,
The inverter control unit,
And determining that a current error exists when the first value calculated by summing the detected first phase current, second phase current, and third phase current is not zero. delete delete According to claim 1,
The inverter control unit,
A motor driving apparatus characterized by accumulating and storing the estimated current error. According to claim 1,
The inverter control unit,
A speed calculating unit calculating a rotor speed of the motor based on the current detected through the output current detecting unit;
A current command generator for generating a current command value based on the calculated speed information and the speed command value;
A voltage command generator for generating a voltage command value based on the current command value and the detected current; And
And a switching control signal output unit outputting a switching control signal for driving the inverter based on the voltage command value. A home appliance comprising the motor drive device of any one of claims 1 to 4, 7 or 8.

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