KR101888084B1 - Power converting apparatus and air conditioner including the same - Google Patents

Abstract

The present invention relates to a power conversion apparatus and an air conditioner having the power conversion apparatus. The power conversion apparatus according to the embodiment of the present invention includes: a capacitor connected to the dc stage; an inverter having a plurality of switching elements, for converting the DC power from the capacitor to an AC power to drive the motor; An output current detection unit connected between the capacitor and the inverter for detecting an output current flowing to the motor, and a switching control signal having a variable pulse width for controlling the inverter based on the output current, And a gate driving signal corresponding to the switching control signal and a turn-on timing variable signal are applied to the gate terminal of the switching element for turning on the switching element. Thus, it is possible to accurately detect the output current despite the ringing phenomenon of the switching element.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converting apparatus and an air conditioner including the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion apparatus and an air conditioner having the power conversion apparatus. More particularly, the present invention relates to a power conversion apparatus and an air conditioner having the power conversion apparatus.

The air conditioner is installed to provide a comfortable indoor environment for humans by discharging cold air to the room to adjust the room temperature and purify the room air to create a pleasant indoor environment. Generally, the air conditioner includes an indoor unit which is constituted by a heat exchanger and installed in a room, and an outdoor unit which is constituted by a compressor, a heat exchanger and the like and supplies the refrigerant to the indoor unit.

On the other hand, current large-capacity air conditioners rectify the input three-phase voltage using a diode, which is a passive element, and drive the motor through the inverter using the rectified voltage.

On the other hand, a ringing phenomenon occurs in the switching element for driving the motor in the air conditioner, and thus the output current can not be accurately detected.

An object of the present invention is to provide a power conversion device capable of accurately detecting an output current despite the ringing phenomenon of a switching element and an air conditioner having the power conversion device.

According to an aspect of the present invention, there is provided a power conversion apparatus including: a capacitor connected to a dc stage; a plurality of switching elements; an inverter for converting a DC power from a capacitor to an AC power to drive the motor; An output current detection unit connected between the capacitor and the inverter for detecting an output current flowing in the motor, and a control unit for controlling the pulse width A gate driving signal corresponding to the switching control signal and a turn-on timing variable signal are applied to a gate terminal of the switching element for turning on the switching element.

According to another aspect of the present invention, there is provided an air conditioner including a compressor for compressing refrigerant, a heat exchanger for performing heat exchange using compressed refrigerant, and a power conversion device for driving the compressor, The power conversion apparatus includes a capacitor connected to the dc stage, an inverter having a plurality of switching elements, for converting a DC power from the capacitor into an AC power to drive the motor, and a drive circuit for outputting a drive signal for driving the switch An output current detection unit connected between the capacitor and the inverter for detecting an output current flowing through the motor; and a control unit for outputting a switching control signal having a variable pulse width for controlling the inverter based on the output current, To turn on the switching element, a gate terminal of the switching element is connected to a gate drive Signal, and a turn-on timing variable signal are applied.

According to an embodiment of the present invention, a power conversion apparatus and an air conditioner having the same include a capacitor connected to a dc stage, and a plurality of switching elements, and converts the DC power from the capacitor to an AC power to drive the motor An output current detection unit connected between the capacitor and the inverter for detecting an output current flowing to the motor, and a control unit for controlling the inverter based on the output current A gate driving signal corresponding to the switching control signal and a turn on timing variable signal are applied to the gate terminal of the switching element for turning on the switching element, The output current can be accurately detected despite the ringing phenomenon of the switching element.

In particular, when the output current detection unit is used as the shunt resistor element connected to the dc short-circuit capacitor, the output current can be accurately detected despite the ringing phenomenon of the switching element. This makes it possible to perform stable motor driving in an air conditioner of a large capacity with a large motor load.

1 is a diagram illustrating a configuration of an air conditioner according to an embodiment of the present invention.
2 is a schematic view of the outdoor unit and the indoor unit of FIG.
3 is a block diagram of a power converter for driving a compressor in the outdoor unit of FIG.
4A is an internal block diagram of the inverter control unit of FIG.
4B is an internal block diagram of the converter control unit of FIG.
5A to 5B are views for explaining a ringing phenomenon by a switching element in an inverter.
6 is a schematic diagram illustrating an operation method of a power conversion apparatus according to an embodiment of the present invention.
Figs. 7A to 14 are views referred to the description of the operation method of Fig.

Hereinafter, the present invention will be described in detail with reference to the drawings.

The suffix "module" and " part "for components used in the following description are given merely for convenience of description, and do not give special significance or role in themselves. Accordingly, the terms "module" and "part" may be used interchangeably.

1 is a diagram illustrating a configuration of an air conditioner according to an embodiment of the present invention.

1, a large-sized air conditioner 50 includes a plurality of indoor units 31 to 35, a plurality of outdoor units 21 and 22 connected to a plurality of indoor units, Remote controllers 41 to 45 connected to the respective indoor units, and a remote controller 10 for controlling the plurality of indoor units and the outdoor units.

The remote controller 10 is connected to a plurality of indoor units 31 to 36 and a plurality of outdoor units 21 and 22 to monitor and control the operation thereof. At this time, the remote controller 10 may be connected to a plurality of indoor units to perform operation setting, lock setting, schedule control, group control, and the like for the indoor units.

The air conditioner may be any of a stand-type air conditioner, a wall-mounted air conditioner, and a ceiling-type air conditioner, but a ceiling-type air conditioner will be described as an example for convenience of explanation. In addition, the air conditioner may further include at least one of a ventilator, an air purifier, a humidifier, and a heater, and may operate in conjunction with the operation of the indoor unit and the outdoor unit.

The outdoor units 21 and 22 are provided with a compressor (not shown) for receiving and compressing the refrigerant, an outdoor heat exchanger (not shown) for exchanging heat between the refrigerant and the outdoor air, an accumulator for extracting the gas refrigerant from the supplied refrigerant, And a four-way valve (not shown) for selecting the flow path of the refrigerant according to the heating operation. In addition, a number of sensors, valves, oil recovery devices, and the like are further included, but a description thereof will be omitted below.

The outdoor units (21, 22) operate the compressor and the outdoor heat exchanger to compress or heat-exchange the refrigerant according to the setting, and supply the refrigerant to the indoor units (31 to 35). The outdoor units 21 and 22 are driven by the request of the remote controller 10 or the indoor units 31 to 35. The number of operation of the outdoor units and the number of operation of the compressors installed in the outdoor units The number of operations is variable.

At this time, the outdoor units (21, 22) are explained on the basis that the plurality of outdoor units supply the refrigerant to the indoor units connected to the indoor units, respectively. However, according to the connection structure of the outdoor units and the indoor units, .

The indoor units 31 to 35 are connected to any one of the plurality of outdoor units 21 and 22 to receive the refrigerant and discharge the cold air to the room. The indoor units 31 to 35 include an indoor heat exchanger (not shown), an indoor fan (not shown), an expansion valve (not shown) in which the refrigerant to be supplied is expanded, and a plurality of sensors (not shown).

At this time, the outdoor units 21 and 22 and the indoor units 31 to 35 are connected to each other via a communication line to transmit and receive data, and the outdoor unit and the indoor unit are connected to the remote controller 10 by a separate communication line, .

The remote controllers 41 to 45 are connected to the indoor units, respectively, to input control commands of the user to the indoor units, and to receive and display status information of the indoor units. At this time, the remote controller communicates wired or wirelessly according to the connection form with the indoor unit, and in some cases, one remote controller is connected to the plurality of indoor units, and the settings of the plurality of indoor units can be changed through one remote control input.

In addition, the remote controllers 41 to 45 may include a temperature sensing sensor therein.

2 is a schematic view of the outdoor unit and the indoor unit of FIG.

Referring to the drawings, the air conditioner 50 is roughly divided into an indoor unit 31 and an outdoor unit 21.

The outdoor unit 21 includes a compressor 102 for compressing the refrigerant, a compressor 102b for driving the compressor, an outdoor heat exchanger 104 serving to dissipate the compressed refrigerant, An outdoor fan 105 which is disposed at one side of the heat exchanger 104 and includes an outdoor fan 105a for accelerating the heat radiation of the refrigerant and an electric motor 105b for rotating the outdoor fan 105a and an outdoor fan 105 for expanding the condensed refrigerant An accumulator 103 for temporarily storing the gasified refrigerant to remove moisture and foreign substances, and then supplying a refrigerant with a predetermined pressure to the compressor, a compressor 106 for compressing the refrigerant, a cooling / heating switching valve 110 for changing the flow path of the compressed refrigerant, And the like.

The indoor unit 31 includes an indoor heat exchanger 109 disposed inside the room and performing a cooling / heating function, an indoor fan 109a disposed at one side of the indoor heat exchanger 109 for promoting heat radiation of the refrigerant, And an indoor air blower 109 composed of an electric motor 109b for rotating the fan 109a.

At least one indoor heat exchanger 109 may be installed. At least one of an inverter compressor and a constant speed compressor may be used as the compressor 102. [

Further, the air conditioner 50 may be constituted by a cooling unit that cools the room, or a heat pump that cools or heats the room.

2, the indoor unit 31 and the outdoor unit 21 are shown as one unit. However, the driving unit of the air conditioner according to the embodiment of the present invention is not limited to this, The present invention is also applicable to an air conditioner, an air conditioner having one indoor unit and a plurality of outdoor units.

3 is a block diagram of a compressor motor drive apparatus in the outdoor unit of Fig.

The compressor 102 in the outdoor unit 21 of Fig. 1 can be driven by the power conversion device 200 for driving the compressor motor 250 to drive the compressor.

The power converter 200 for driving the compressor includes an inverter 220 for outputting a three-phase AC current to the compressor motor 250, an inverter controller 230 for controlling the inverter 220, A converter 210 for supplying power, and a converter controller 215 for controlling the converter 210. [

The power conversion apparatus 200 receives the AC power from the system, converts the power, and supplies the converted power to the compressor motor 250. Accordingly, the power conversion apparatus 200 may be referred to as a compressor driving apparatus.

The power conversion apparatus 200 according to an embodiment of the present invention includes a capacitor C connected to the dc stage and a plurality of switching elements, and converts the DC power from the capacitor C into an AC power A gate driver 233 for outputting a drive signal for driving the switching element, and an inverter 220 connected between the capacitor C and the inverter 220 for detecting an output current flowing to the motor And an inverter control unit 230 for outputting a switching control signal Sic having a variable pulse width for controlling the inverter 220 based on the output current, The gate drive signal Ssg corresponding to the switching control signal Sic and the turn-on timing variable signal Sca are applied to the gate terminal of the switching element.

In particular, when the output current is difficult to detect due to the ringing phenomenon, the level of the turn-on timing variable signal Sca is increased so that the turn-on time of the switching element is shortened, So that it can be detected accurately.

In particular, when the output current detection unit is used as the shunt resistor element connected to the dc short-circuit capacitor, the output current can be accurately detected despite the ringing phenomenon of the switching element. This makes it possible to perform stable motor driving in an air conditioner of a large capacity with a large motor load.

Meanwhile, the converter 210 that supplies the DC power to the inverter 220 can receive the three-phase AC power and can convert the DC power.

To this end, the converter 210 may include a rectifier (not shown) and a boost converter (not shown). In addition, a reactor (not shown) may be further provided.

On the other hand, the converter 210 may include a rectifying section (not shown) and an interleave boost converter (not shown).

A capacitor C is connected to the output terminal of the converter 210. The capacitor C may store the power output from the converter 210. [ Since the power source output from the converter 210 is a dc power source, it can be called a dc-stage capacitor.

The converter control unit 215 can control the converter 210 having the switching elements.

The inverter 220 includes a plurality of inverter switching elements and converts the smoothed direct current power supply Vdc into a three-phase alternating current power with variable frequency by the on / off operation of the switching element and outputs the three- .

More specifically, the inverter 220 may include a plurality of switching elements. For example, the upper arm switching elements Sa, Sb, Sc and the lower arm switching elements S'a, S'b, S'c are connected in series to each other and a total of three pairs of upper and lower arm switching elements Can be connected to each other in parallel (Sa & S'a, Sb & S'b, Sc & S'c). Diodes may be connected in anti-parallel to each switching element Sa, S'a, Sb, S'b, Sc, S'c.

The inverter control unit 230 can output the inverter switching control signal Sic to the inverter 220 in order to control the switching operation of the inverter 220. [

Inverter switching control signal (Sic) is a switching control signal of a pulse width modulation (PWM), may be generated on the basis of the motor 250, the output current (i _o) flowing through the output. The output current (i _o ) at this time can be detected from the output current detection section (E).

The dc short-circuit voltage detector B can detect the voltage Vdc stored in the dc short-circuit capacitor C. To this end, the dc voltage detection unit B may include a voltage trnasformer (VT) or a resistance element. The detected dc voltage (Vdc) is input to the inverter control unit 230.

An output current detector (E) may detect an output current (i _o) flowing between the inverter 420 and the motor 250. That is, the current flowing in the motor 250 can be detected.

The output current detection unit E can detect all of the output currents ia, ib, ic of each phase or can detect the output currents of two phases using the three-phase balance.

The output current detector E may be located between the inverter 220 and the motor 250. For current detection, a current transformer (CT), a shunt resistor, or the like may be used.

The output current detection unit E is connected between the capacitor C and the inverter 220 and is capable of detecting the output current flowing through the motor 250. [

That is, the output current detector E according to the embodiment of the present invention may include a one-shunt resistor element connected to the dc stage, as shown in FIG. 8A. This will be described later with reference to FIG.

4A is an internal block diagram of the inverter control unit of FIG.

4A, the inverter control unit 230 includes an axis transformation unit 310, a position estimation unit 320, a current command generation unit 330, a voltage command generation unit 340, an axis transformation unit 350, And a switching control signal output unit 360.

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

On the other hand, the axis converting unit 310 can convert the two-phase current i ?, i? Of the still coordinate system into the two-phase current id, iq of the rotating coordinate system.

)를 추정한다. 또한, 추정된 회전자 위치(

)에 기초하여, 연산된 속도(

)를 출력할 수 있다.The position estimating unit 320 estimates the position of the rotor 250 of the motor 250 based on the two-phase currents i? And i? Of the stationary coordinate system converted by the axis converting unit 310

). In addition, the estimated rotor position (

), The calculated speed (

Can be output.

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

)와 목표 속도(ω)의 차이인 속도 지령치(ω^* _r)에 기초하여, PI 제어기(435)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 generates the current command

) Based on the speed command value ω ^* _r and the target speed ω and generates the current command value i ^* _q based on the speed command value ω ^* _r . For example, the current command generation section 330 generates the current command

The PI controller 435 performs the PI control based on the speed command value? ^* _{R that} is the difference between the target speed? And the target speed?, And generates the current command value i ^* _q . In the figure, the q-axis current command value (i ^* _q ) is exemplified by the current command value, but it is also possible to generate the d-axis current command value (i ^* _d ) unlike the figure. On the other hand, the value of the d-axis current command value i ^* _d may be set to zero.

On the other hand, the current command generation section 330 may further include a limiter (not shown) for limiting the current command value (i ^* _q ) so that the current command value (i ^* _q ) does not exceed the allowable range.

Next, the voltage command generating unit 340 generates the voltage command generating unit 340 with the d-axis and q-axis currents (i _d , i _q ) axially transformed into the two-phase rotational coordinate system in the axial converting unit and the current command value based on ^{_{i * d, i * q)}} , and generates a d-axis, q-axis voltage command value ^{_{(v * d, v * q}} ). For example, the voltage command generation unit 340 performs PI control in the PI controller 444 based on the difference between the q-axis current (i _q ) and the q-axis current command value (i ^* _q ) It is possible to generate the axial voltage command value v ^* _q . Further, voltage command generation unit 340, on the basis of the difference between the d-axis current (i _d) and, the d-axis current command value (i ^* _d), and performs the PI control in the PI controller (448), d-axis voltage It is possible to generate the command value v ^* _d . On the other hand, the value of the d-axis voltage command value v ^* _d may be set to zero corresponding to the case where the value of the d-axis current command value i ^* _d is set to zero.

The voltage command generator 340 may further include a limiter (not shown) for limiting the level of the d-axis and q-axis voltage command values v ^* _d and v ^* _q so as not to exceed the permissible range .

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

)와, d축, q축 전압 지령치(v^* _d,v^* _q)를 입력받아, 축변환을 수행한다.The axis transforming unit 350 transforms the position calculated by the velocity calculating unit 320

) And the d-axis and q-axis voltage command values (v ^* _d , v ^* _q ).

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

) Can be used.

Then, the axial conversion unit 350 performs conversion from the two-phase stationary coordinate system to the three-phase stationary coordinate system. Through this conversion, the axial conversion unit 1050 outputs the three-phase output voltage instruction values v ^* a, v ^* b, v ^* c.

The switching control signal output section 360 generates the switching control signal Sic for inverter according to the pulse width modulation (PWM) method based on the three-phase output voltage instruction values v ^* a, v ^* b and v ^* And outputs it.

In particular, the switching control signal output section 360 outputs the spatial vector pulse width modulation SVPWM based on the d-axis and q-axis voltage command values v ^* _d and v ^* _q and the high frequency voltage command value V ^* dqh. The inverter switching control signal Sic can be generated and output.

The output inverter switching control signal Sic can be converted into a gate driving signal in the gate driver (233 in FIG. 8A) and input to the gate of each switching element in the inverter 420. As a result, the switching elements Sa, S'a, Sb, S'b, Sc, and S'c in the inverter 420 perform the switching operation.

4B is an internal block diagram of the converter control unit of FIG.

The converter control unit 215 may include a current command generation unit 410, a voltage command generation unit 420, and a switching control signal output unit 430.

Based on the dc terminal voltage (Vdc) and the dc terminal voltage command value (V ^* dc) detected by the output voltage detecting section (B), that is, the dc terminal voltage detecting section (B), the current command generating section (410) The q-axis current command value (i ^* _d , i ^* _q ) can be generated.

Voltage command generation section 420 d, q-axis current instruction value through the like ^{_{(i * d, i * q}} ) and the input current detected (i _L) by the PI control based on the d, q-axis voltage command value (v ^* _d , v ^* _q ).

Switching control signal output unit 430 includes a d, q-axis voltage command value (v ^* _d, v ^* _q) on the basis of a converter switching control for driving the boost switching element (S) in the boost converter 515 of Figure 5a And can output the signal Scc to the boost converter 515a.

5A to 5B are views for explaining a ringing phenomenon by a switching element in an inverter.

5A is a diagram showing the first sod rock switching device Sa among a plurality of switching elements Sa & S a, Sb & S'b, Sc & S'c in the inverter.

The plurality of switching elements may be implemented as an IGBT or a MOSFET.

On the other hand, when a plurality of switching elements is implemented as an IGBT or a MOSFET, a gate driver for outputting a gate driving signal may be used.

On the other hand, parasitic inductance and a freewheeling diode are inevitably present in each of the plurality of switching elements.

5A, the gate parasitic inductance Lg is applied to the gate terminal of the first upper arm rocking element Sa, the collector parasitic inductance Lc is connected to the collector terminal of the first upper arm rocking element Sa, A gate parasitic inductance Le is connected to an emitter terminal of the transistor Sa and a freewheeling diode is connected between the emitter terminal and the collector terminal.

On the other hand, a gate resistor Rg is connected to the gate terminal of the first upper arc-rock switching device Sa.

As the gate driving signal is applied to the gate terminal of the first dummy arm switching element Sa, the first dummy arm switching element Sa is turned on.

On the other hand, when the first upper arm switching device Sa is turned on due to the reverse recovery characteristics of the parasitic inductances Lg, Lc, and Le and the freewheeling diode, Likewise, a current peak and a current flowing in the first upper arc-rock switching device Sa, particularly, a ringing phenomenon in which the collector current Ic is shaken occur.

Accordingly, it is preferable to detect the current after the ringing period Tri.

On the other hand, when the output current detecting section E is connected between the capacitor C and the inverter 220 and includes a one-shunt resistor element, the output current detecting section E sequentially detects the phase current flowing in the motor do.

According to such a one-shunt method, a turn-on interval of each switching element in the inverter is narrow, and a dead time period in which the output current can not be detected may occur.

Such a dead time may be caused by the above-mentioned ringing phenomenon or the like when the turn-on interval of each switching element in the inverter is small.

In the present invention, a method of detecting an output current or a phase current stably using a one-shunt resistor element despite the ringing phenomenon is proposed.

To this end, in the present invention, in addition to the gate drive signal Ssg applied to the gate terminal, the turn-on timing variable signal Sca is further applied so that the ringing time is reduced. This will be described in more detail with reference to FIG.

FIG. 6 is a flowchart illustrating a method of operating the power conversion apparatus according to an embodiment of the present invention, and FIGS. 7A to 14 are diagrams referred to the description of the operation method of FIG.

First, referring to Fig. 6, the output current detection unit E in the power conversion apparatus 200 detects the output current io (S610)

The inverter control unit 230 in the power conversion apparatus 200 receives the detected output current io.

Next, the inverter control unit 230 in the power conversion apparatus 200 determines the pulse width duty based on the output current io (S620), and generates and outputs the switching control signal having the determined pulse width variation .

As shown in FIG. 4A, the inverter control unit 230 estimates the speed of the motor based on the output current, and sets the pulse width duty to be larger as the difference between the estimated speeds outside the speed command value increases. Then, the switching control signal corresponding to the set pulse width duty is outputted.

Next, the inverter control unit 230 in the power conversion apparatus 200 compares the output current detectable period Tsen corresponding to the pulse width duty with the output current detection minimum period Tmin (S632).

The inverter control unit 230 sets the turn-on time of the switching element to be shorter when the output current detectable period Tsen corresponding to the pulse width duty is smaller than the output current detection minimum period Tmin (S634 ).

Then, the inverter control unit 230 controls the turn-on timing variable signal corresponding to the shortened turn-on time to be outputted (S638).

The inverter control unit 230 outputs a switching control signal corresponding to the pulse width duty, and the gate driving unit 233 outputs the gate driving signal Sgc corresponding to the pulse width duty (S640).

Thus, the switching element in the inverter 220 can shorten the turn-on time. Therefore, it is possible to accurately detect the output current despite the ringing phenomenon.

On the other hand, the turn-on timing variable signal Sca may be output from the gate driver 233 or from another turn-on timing controller 236. This will be described later with reference to Fig. 8A.

7A and 7B illustrate a collector current waveform Ic, a collector emitter voltage waveform Vce, and a gate emitter voltage waveform Vce flowing in the switching element Sa as shown in FIG. 5A.

Particularly, FIG. 7A shows that the ringing phenomenon appears more severely, and thus the current detection is possible at the time point P1.

Fig. 7B illustrates that the ringing phenomenon is weaker than that in Fig. 7A, so that the current detection is possible at P2 time point shorter than P1.

8A and 8B illustrate an output current detector E having the shunt resistive element Rs connected to the dc terminal between the capacitor C and the inverter 220 and the inverter controller 230 and the like.

8A shows a case where the inverter 220 outputs a switching control signal Sic having a variable pulse width based on the output current io detected by the output current detection unit E and the gate driving unit 233 outputs the switching control signal Sic, The turn-on timing controller 236 outputs the gate drive signal Sgc based on the switching control signal Sic having a variable pulse width and outputs the gate drive signal Sgc based on the control signal Sco of the inverter control unit 220, And outputs a turn-on timing variable signal Sca whose level is variable.

Particularly, the turn-on timing variable signal Sca having a variable level is input to the gate driver 233 and output from the gate driver 233 together with the gate drive signal Sgc.

On the other hand, the gate drive signal Sgc and the turn-on timing variable signal Sca can be input to the gate terminal of the switching element in the inverter 220. [

For example, the higher the level Lva of the turn-on timing variable signal Sca, the higher the level of the signal input to the gate terminal, so the turn-on time can be shortened. As a result, a margin for detecting the output current can be ensured despite the ringing phenomenon.

Accordingly, the turn-on time of the switching element in the inverter 220 can be varied.

On the other hand, when the turn-on time is not required to be shortened, the level Lva of the turn-on timing variable signal Sca may be lowered to reduce electromagnetic noise such as EMI caused by switching of the switching element.

8B is different from FIG. 8A in that the turn-on timing controller 236 is not provided.

Instead, the gate driver 233 may perform the function of the turn-on timing controller 236 as well.

That is to say, the gate driver 233 can output the turn-on timing-varying signal Sca which is variable in level, together with the gate drive signal Sgc, based on the control signal Sco of the inverter controller 220 .

For example, the higher the level Lva of the turn-on timing variable signal Sca, the higher the level of the signal input to the gate terminal, so the turn-on time can be shortened. As a result, a margin for detecting the output current can be ensured despite the ringing phenomenon.

9A shows the case where the inverter 220 outputs the switching control signal Sic having the variable pulse width based on the output current io detected by the output current detection unit E and the gate driving unit 233 outputs the switching control signal Sic, The turn-on timing controller 236 outputs the gate drive signal Sgc based on the switching control signal Sic having a variable pulse width and outputs the gate drive signal Sgc based on the control signal Sco of the inverter control unit 220, And outputs a turn-on timing variable signal Sca whose level is variable.

8A, the turn-on timing varying signal Sca can be input directly to the gate terminal of the switching element Sa without passing through the gate driver 233. [

Next, FIG. 9B illustrates that the gate driver 233 also performs the function of the turn-on timing controller 236, as in FIG. 8B.

That is to say, the gate driver 233 can output the turn-on timing-varying signal Sca which is variable in level, together with the gate drive signal Sgc, based on the control signal Sco of the inverter controller 220 .

10A and 10B are graphs showing waveforms of a gate driving signal Sgc, a gate voltage waveform Vgs, a collector current waveform Ic and a collector emitter voltage waveform Vce applied to the switching element Sa as shown in FIG. ) And a gate current waveform (Ig).

In particular, Fig. 10A illustrates a case where the time for detecting the output current is sufficiently secured, and the output current detection minimum period Tmina is much larger than the output current detection minimum period Tminb of Fig. 10B.

Accordingly, in the case of Fig. 10B, it is desirable to control the level Lva of the turn-on timing-varying signal Sca to increase as described above. That is, it is preferable to control the turn-on time of the switching element to be shortened.

FIG. 11 illustrates that the slew rate in the gate voltage waveform Vgs is increased by application of the turn-on timing varying signal Sca.

11A illustrates the gate drive signal waveform Sgc applied to the switching element Sa and FIG. 11B illustrates the gate voltage waveform Vgs1 by the gate drive signal waveform Sgc. . It can be seen that the slew rate which is the voltage change rate is gentle.

11 (c) illustrates a level-varying turn-on timing variable signal waveform Sca. FIG. 11 (d) shows a turn-on and turn-off timing variable signal waveform Sca, The gate voltage waveform Vgs2 due to the gate voltage Sgc is exemplified.

Referring to the drawing, it can be seen that the slew rate, which is the rate of change of the voltage of the gate voltage waveform Vgs2 in FIG. 11 (d), which is the voltage change rate, is increased compared to the gate voltage waveform Vgs1 of FIG. Able to know.

Thus, the turn-on time of the switching element can be shortened.

12 illustrates detection of the output current io, in particular, the a-phase current through the output current detector E connected to the dc stage.

The output current detecting section E detects the output current through the one-shunt resistor element Rs, so that the currents of a, b, and c can be detected by time division according to the switching pattern of the inverter 220. [

13A is a diagram showing a switching vector when the switching pattern of the inverter 220 is (1, 0, 0).

13B is a diagram showing a switching vector when the switching pattern of the inverter 220 is (1, 1, 0).

13B, when the switching pattern of the inverter 220 is (1, 0, 0), the output current detecting section E can detect the a-phase current, (1, 1, 0), the output current detecting section E can detect the c-phase current.

On the other hand, Fig. 14 is a diagram showing the switching vector when the switching pattern of the inverter 220 is (1,0,0), (1,1,0).

At this time, in the a-phase switching device Sa, a ringing phenomenon occurs in accordance with the turn-on of the switching device during the period of tria, and a ringing phenomenon occurs in the b- In the c-phase switching device Sc, a ringing phenomenon occurs due to the turn-on of the switching device during the Tric period.

In this case, by further applying a level-convertible turn-on timing varying signal Sca to the gate terminal of the switching element in addition to the gate driving signal Ssg, the turn-on time of each switching element is varied And the ringing period can be further shortened.

After the turn-on point of each switching element is varied, it is possible to stably detect the output current, in particular, the phase current through the output current detector E. Thus, the motor drive can be stably performed.

The power conversion apparatus and the air conditioner having the power conversion apparatus according to the present invention are not limited to the configuration and method of the embodiments described above, Or some of them may be selectively combined.

Meanwhile, the operation method of the power conversion apparatus or the air conditioner of the present invention can be implemented as a code that can be read by a processor on a processor-readable recording medium provided in a power conversion apparatus or an air conditioner. The processor-readable recording medium includes all kinds of recording apparatuses in which data that can be read by the processor is stored. Examples of the recording medium that can be read by the processor include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may also be implemented in the form of a carrier wave such as transmission over the Internet . In addition, the processor-readable recording medium may be distributed over network-connected computer systems so that code readable by the processor in a distributed fashion can be stored and executed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention.

Claims (10)

a capacitor connected to the dc stage;
An inverter having a plurality of switching elements, for converting a DC power from the capacitor to an AC power to drive the motor;
A gate driver for outputting a driving signal for driving the switching element;
An output current detector connected between the capacitor and the inverter for detecting an output current flowing to the motor;
And a control unit for outputting a switching control signal having a variable pulse width for controlling the inverter based on the output current,
Wherein,
A gate driving signal corresponding to the switching control signal and a turn-on timing variable signal to the gate terminal of the switching element for turning on the switching element,
And controls to output a turn-on timing variable signal corresponding to a shorter turn-on time than when the output current detection minimum time is shorter than the output current detection minimum time when the output current detectable time is smaller than the output current detection minimum time. Device. The method according to claim 1,
Wherein the gate driver comprises:
Wherein the control unit controls the level of the turn-on timing variable signal so that the turn-on time of the switching element becomes shorter when the output current detectable time is smaller than the output current detection minimum time. The method according to claim 1,
Wherein the gate driver comprises:
And controls the level of the turn-on timing variable signal to be lower when the output current detectable time is equal to or greater than the output current detection minimum time. The method according to claim 1,
Wherein the output current detection unit sequentially detects a phase current flowing in the motor. The method according to claim 1,
And a turn-on timing controller for outputting the turn-on timing variable signal,
The turn-
And controls the level of the turn-on timing variable signal to increase so that the turn-on time of the switching element becomes shorter. The method according to claim 1,
And a turn-on timing controller for outputting the turn-on timing variable signal. The method according to claim 1,
And a turn-on timing controller for outputting the turn-on timing variable signal,
Wherein the output current detection unit sequentially detects a phase current flowing in the motor. The method according to claim 1,
And a converter for converting the input AC power to DC power and outputting the DC power converted to the dc stage. The method according to claim 1,
Wherein,
An estimating unit that estimates a rotor position and a speed of the motor based on the output current;
A current command generator for generating a current command value based on the estimated speed and speed command value;
A voltage command generator for generating a voltage command value based on the current command value and the output current flowing to the motor;
And a switching control signal output unit for generating and outputting the inverter switching control signal based on the voltage command value. A compressor for compressing the refrigerant;
A heat exchanger for performing heat exchange using the compressed refrigerant; And
The air conditioner according to any one of claims 1 to 9, for driving the compressor.

Images