KR20160058437A - Power converter and air conditioner including the same - Google Patents

Abstract

The present invention relates to a power converter, and an air conditioner having the same. According to an embodiment of the present invention, the power converter comprises: a buck boost converter for converting inputted alternating current power into direct current power, and operating at least one from a buck mode or a boost mode; and a converter control unit for controlling the buck boost converter. The buck boost converter includes: an upper buck switching element and a lower diode element which are bridged to each other; a boost switching element; and an inductor connected between the buck switching element and the boost switching element. Therefore, raising voltage and reducing voltage are possible.

Description

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

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion device and an air conditioner having the same, and more particularly, to a power conversion device capable of boosting and stepping down, and an air conditioner having the same.

The air conditioner is disposed in a room such as a room, a living room, an office or a business store, and is capable of maintaining a comfortable indoor environment by controlling the temperature, humidity, cleanliness and airflow of the air.

The air conditioner is generally divided into an integral type and a separated type. The integral type and the separate type are the same as the functional type, but the integral type is formed by integrating the functions of cooling and heat dissipation to form a hole in the wall of the house or by hanging the device on the window. Side, an outdoor unit that performs heat dissipation and compression functions is installed, and the two devices separated from each other are connected by a refrigerant pipe.

On the other hand, as requirements for high performance and high efficiency of the air conditioner have been increased, various efforts have been tried.

SUMMARY OF THE INVENTION An object of the present invention is to provide a power conversion device capable of boosting and stepping down, and an air conditioner having the same.

According to an aspect of the present invention, there is provided a power conversion apparatus including: a buck boost converter that converts an input AC power to a DC power and operates in at least one of a buck mode and a boost mode; Converter control section, wherein the buck-boost converter includes an upper buck switching element and a lower-stage diode element bridged with each other, a boost switching element, and an inductor connected between the buck switching element and the boost switching element.

According to another aspect of the present invention, there is provided a power conversion apparatus including: a buck-boost converter that converts an input AC power into a DC power and operates in at least one of a buck mode and a boost mode; Wherein the buck boost converter includes a buck switching element performing switching in a buck mode, a boost switching element performing switching in a boost mode, and an inductor connected between the buck switching element and the boost switching element, And a diode element for rectifying the AC power. In the boost mode, energy is stored in the inductor based on the current flowing through the AC power source, the buck switching element, the inductor, the boost switching element, and the diode element, Based on the current flowing through the buck switching element, the inductor, and the diode element. And consumes the energy stored in the inductor.

According to another aspect of the present invention, there is provided an air conditioner including a compressor and a power conversion unit for supplying driving power to a motor in the compressor. The power conversion unit converts the input AC power into a DC power A buck boost converter operable in at least one of a buck mode or a boost mode and a converter control for controlling a buck boost converter, the buck boost converter comprising: an upper buck switching element and a lower stage diode element bridged with each other; And an inductor connected between the buck switching element and the boost switching element.

According to an embodiment of the present invention, a power conversion device and an air conditioner having the same include a buck-boost converter that converts input AC power to DC power and operates in at least one of a buck mode and a boost mode, Wherein the buck-boost converter includes an upper buck switching element and a lower-stage switching element bridged with each other, a boost switching element, and an inductor connected between the buck switching element and the boost switching element, .

Particularly, a buck-boost converter allows boosting and step-down without a rectifying part such as a bridge diode.

On the other hand, the power loss can be reduced by reducing the number of circuit elements on the conduction path in the boost mode.

1 is a configuration diagram of an air conditioner according to an embodiment of the present invention.
Fig. 2 is a schematic view of the air conditioner of Fig. 1. Fig.
3 is an internal block diagram of the power converter of the outdoor unit of FIG.
4A illustrates an example of a circuit diagram of a converter in the power conversion apparatus of FIG.
Fig. 4B illustrates another example of a circuit diagram of a converter in the power converter of Fig.
Figure 5 illustrates an internal block diagram of the converter control of Figure 4A.
6A and 6B are views referred to in the description of the operation of FIGS. 4A to 4B.
Fig. 7 is a diagram referred to in the description of the converter operation of Fig. 4A.
Figs. 8A-8B are diagrams referred to for explaining the boost mode operation of the converter of Fig. 4A.
Figures 9A-9B are diagrams for the buck mode operation of the converter of Figure 4B.
10 is a diagram referred to for explaining the operation of the converter of FIG. 4A according to the dc voltage.
Fig. 11 illustrates a circuit diagram of an inverter in the power converter of Fig. 3;
12 is an internal block diagram of the inverter control unit 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.

FIG. 1 is a schematic view of an air conditioner according to an embodiment of the present invention, and FIG. 2 is a schematic view of the air conditioner of FIG. 1

Referring to the drawings, an air conditioner 100 includes an outdoor unit 150 and an indoor unit 170.

The outdoor unit 150 operates in a cooling mode or a heating mode in response to a request of the connected indoor unit 170 or an external control command and supplies the refrigerant to the indoor unit 170.

To this end, the outdoor unit 150 includes a compressor 152 that compresses the refrigerant, a compressor motor 152b that drives the compressor, an outdoor heat exchanger 154 that dissipates the compressed refrigerant, An outdoor fan 155 disposed at one side of the outdoor heat exchanger 154 and configured to include an outdoor fan 155a for accelerating the heat radiation of the refrigerant and an electric motor 5b for rotating the outdoor fan 155a, An accumulator (156) for expanding the refrigerant, a cooling / heating switching valve (160) for switching the flow path of the compressed refrigerant, a condenser for temporarily storing the gasified refrigerant to remove moisture and foreign substances, (153), and the like. At least one of an inverter compressor and a constant speed compressor may be used as the compressor 152. [

The outdoor unit 150 may further include at least one pressure sensor (not shown) for measuring the pressure of the refrigerant, at least one temperature sensor (not shown) for measuring the temperature, and the like.

The indoor unit 170 includes an indoor heat exchanger 208 disposed inside the room and performing a cooling / heating function, an indoor fan 209a disposed at one side of the indoor heat exchanger 208 for promoting heat radiation of the refrigerant, And an indoor air blower 209 composed of an electric motor 209b for rotating the indoor fan 209a. At least one indoor heat exchanger 208 may be installed.

The indoor unit 170 may further include a discharge port (not shown) for discharging the heat-exchanged air and a wind direction control unit (not shown) for closing the discharge port (not shown) and controlling the direction of the discharged air. For example, a vane may be provided to open and close at least one of an air inlet (not shown) and an air outlet (not shown), and the vane may open and close the air inlet and the air outlet, And the direction of the discharge air.

On the other hand, the indoor unit 170 can adjust the air volume by controlling the air sucked in and the air sucked in accordance with the rotating speed of the indoor fan 209a.

The indoor unit 170 may further include a display unit (not shown) for displaying an operation state and setting information of the indoor unit 170, and an input unit (not shown) for inputting setting data. In addition, it may further include an indoor temperature sensing unit (not shown) for sensing a room temperature, a human body sensing unit (not shown) for sensing a human body in the indoor space, and the like.

On the other hand, the air conditioner 100 may be composed of a cooler for cooling the room, or a heat pump for cooling or heating the room.

Although the indoor unit 170 is shown as a stand type in the drawing, the indoor unit 170 may be of a ceiling type or a wall type, and may have various forms such as an integral type in which there is no distinction between an outdoor unit and an indoor unit.

On the other hand, the indoor unit 170 and the outdoor unit 150 are connected by a refrigerant pipe, and cold air is discharged from the indoor unit 170 to the room as the refrigerant circulates. At this time, a plurality of indoor units 170 may be connected to one outdoor unit 150, and at least one indoor unit may be connected to each of the plurality of outdoor units.

The indoor unit 170 and the outdoor unit 150 may be connected to each other via a communication line to transmit / receive a control command according to a predetermined communication method.

On the other hand, the compressor 152 can be driven by the driving power supplied through the following power conversion device 200. [ Specifically to the motor in compressor 152. The driving power from the power inverter 200 can be supplied.

Fig. 3 is an internal block diagram of the power converter of the outdoor unit of Fig. 1, and Fig. 4A illustrates an example of a circuit diagram of the converter in the power converter of Fig.

The power conversion apparatus 200 according to the embodiment of the present invention may include a converter 410, a converter control unit 415, a capacitor C, an inverter 420, and an inverter control unit 430.

The converter 410 converts the input AC power into DC power and outputs the DC power. And in particular, to the capacitor C disposed at the output terminal of the converter 410. [

On the other hand, both ends of the capacitor C are stored with a DC power source, and hence can be called a dc stage. The power supply at both ends of the capacitor C may be referred to as a dc power source.

On the other hand, a load 205 as shown in FIG. 4A can be connected to both ends of the capacitor C. The load 205 at this time may be a concept including the inverter 420 of FIG. 3 and the motor 250.

In the embodiment of the present invention, a buck boost converter is used as the converter 410. In particular, in accordance with an embodiment of the present invention, the buck-boost converter 410 is operable in a buck mode or a boost mode, without a bridge diode, so that a bridgeless buck boost converter .

Accordingly, the buck-boost converter 410 directly receives the input AC power instead of receiving the rectified power.

4A, the buck-boost converter 410 includes upper and lower diode elements D1 and D2 bridged with each other, a boost switching element S3 and a buck switching element S1 And an inductor L1 connected between the boost switching element S3 and the boost switching element S3. In addition, a diode element D3 for preventing reverse flow can be further provided between the boost switching element S3 and the capacitor C.

The buck-boost converter 410 of FIG. 4A converts the input AC power supply Vin into DC power and is operable in at least one of a buck mode or a boost mode.

The buck-boost converter 410 of FIG. 4A is configured to supply the alternating-current power Vin, the buck switching element S1, the inductor L1, and the inductor L1 during a positive half period of the input AC power supply Vin in a boost mode. The boost switching element S3, and the diode element D2, and stores the energy in the inductor L1.

The buck-boost converter 410 shown in Fig. 4A is configured to supply the AC power Vin, the buck switching element S2, the inductor L1, and the inductor L1 during the negative half period of the input AC power in the boost mode, The boost switching element S3, and the diode element D1, based on the current flowing through the inductor L1.

The buck-boost converter 410 of FIG. 4A is configured to switch the buck switching element S2, the inductor L1, the diode elements D3, and D3 during the positive half period of the input AC power supply Vin in the buck mode, The capacitor C, and the diode element D2, consumes the energy stored in the inductor L1.

The buck-boost converter 410 of FIG. 4A is configured to switch the buck switching element S1, the inductor L1, the diode elements D3, and D3 during the negative half period of the input AC power supply Vin in the buck mode, The capacitor C, and the diode element Dl, consumes the energy stored in the inductor Ll.

On the other hand, the converter control section 415 controls the buck switching elements S1 and S2 in the buck-boost converter 410 and the boost switching elements S1 and S2 in the buck-boost converter 410 based on the dc voltage terminal Vdc or the dc voltage terminal voltage value at both ends of the capacitor C. [ (S3).

That is, the converter control section 415 can output the converter switching control signal Scc to the inverter 420 to control the switching operation in the buck-boost converter 410. [ The converter switching control signal Scc at this time is a concept that includes the first buck switching control signal SS1, the second buck switching control signal SS2 and the boost switching control signal SS3 in Fig. .

For example, the converter control unit 415 switches the boost switching element S3 so as to operate in the boost mode when the dc step voltage (Vdc) or the dc step voltage command value is larger than the voltage of the input AC power (Vin) and switches the buck switching elements S1 and S2 to operate in a buck mode when the dc terminal voltage Vdc or the dc terminal voltage command value is smaller than the voltage of the input AC power source Vin ). The switching at this time may be pulse width variable (PWM) based switching.

On the other hand, the converter control unit 415 controls the buck switching elements S1 and S2 such that the buck switching elements S1 and S2 operate in the boost mode when the dc step voltage (Vdc) or the dc step voltage command value is larger than the peak value of the input ac power (Vin) And the boost switching element S3 can be controlled to be switched.

On the other hand, the inductor L1 is commonly used in the buck mode and the boost mode. As a result, the manufacturing cost can be reduced.

On the other hand, the buck switching elements S1 and S2 can provide a return current path to the inductor L1 in the buck mode.

Meanwhile, the boost mode operation of the buck boost converter 410 will be described below with reference to FIGS. 8A to 8B, and the buck mode operation of the buck boost converter 410 will be described below with reference to FIGS. 9A to 9B.

The power conversion apparatus 200 includes an input current detection unit A for detecting an input current of the input AC power source, an output terminal for detecting the output terminal voltage of the buck boost converter 410, that is, the voltage of the dc- (Not shown) for detecting a current flowing through the inductor L1 in the buck-boost converter 410,

The input current detecting section A can detect an input current from the input AC power source. For this, the input current detector A may include a current transformer (CT), a shunt resistor, and the like. The detected input current Is may be input to the converter control unit 415 as a discrete signal in the form of a pulse.

The output voltage detecting unit B, that is, the dc step voltage detecting unit B, can detect the output terminal voltage of the buck boost converter 410. In particular, the voltage Vdc across the capacitor C can be detected.

The capacitor C is disposed between the converter 410 and the inverter 420 and stores the output DC power of the buck boost converter. In the drawing, one element is exemplified by the smoothing capacitor C, but a plurality of elements are provided so that the element stability can be ensured.

If a load including the inverter 420 and the motor 205 is referred to as a load, both ends of the capacitor C of the power conversion apparatus may be connected to a load 205 as shown in the drawing. Accordingly, the dc short-circuit voltage (V _dc ) can correspond to the voltage of the load 205. The detected output voltage V _dc can be input to the converter control unit 415 as a discrete signal in the form of a pulse.

The inverter 420 includes a plurality of inverter switching elements and converts the smoothed DC power supply Vdc into a three-phase AC power supply (va, vb, vc) having a predetermined frequency by on / off operation of the switching element, And outputs it to the synchronous motor 250. The motor 250 at this time may be a motor in the compressor.

The inverter control unit 430 outputs the inverter switching control signal Sic to the inverter 420 to control the switching operation of the inverter 420. [ Inverter switching control signal (Sic) is a switching control signal of a pulse width modulation (PWM), the output current detection section is output is generated and based on the output current (i _o) detected from (E in Fig. 11).

Next, Fig. 4B illustrates another example of the circuit diagram of the converter in the power converter of Fig.

4B illustrates a rectification unit 405 having bridge diode elements Da, Db, Dc, and Dd and a buck-boost converter 410a of a cascade type. do.

The buck-boost converter 410a includes a buck switching element Sa to which an anti-parallel diode is attached, a diode element De for a buck mode, an inductor La, a boost switching element Sb, and a reverse current prevention diode element Dr .

According to the power conversion apparatus of Fig. 4B, in the boost mode operation, when the boost switching device Sb is turned on, the input power supply Vin is connected to the diode device Da, the buck switching device Sa, La, a boost switching element Sb and a diode element Dd, and energy is stored in the inductor La. The buck switching element Sb is turned off and is supplied to the load 205 through the diode element Da, the buck switching element Sa, the inductor La and the reverse current prevention diode element Dr, The stored energy is transferred.

According to the power conversion apparatus of FIG. 4B, since two diode elements are required to pass through the diode during the boost mode operation, power consumption due to the diode elements is further increased as compared with the case of passing through one diode element of FIG. 4A. Thus, the power conversion efficiency becomes better than in Fig. 4B, and Fig. 4A is better.

As a result, with the bridgeless buck-boost converter 410 of FIG. 4A, the power loss can be reduced by reducing the number of circuit elements on the conduction path in the boost mode.

Figure 5 illustrates an internal block diagram of the converter control of Figure 4A.

The converter control unit 415 may include a current command generation unit 510, a voltage command generation unit 520, and a switching control signal output unit 530.

Current command generating unit 510 a, the output voltage detection unit (B), i.e., such as the PI control on the basis of the dc terminal voltage (Vdc) and a dc terminal voltage command value (V ^* dc) detected by the dc terminal voltage detector (B) (I ^* _d , i ^* _q ) can be generated from the _d- axis and q-axis current command values.

Voltage command generation section 520 d, q-axis current command value ^{_{(i * d, i * q}} ) from the like PI controller based on the detected inductor (reactor), current (i _L) to be d, q-axis voltage command value ( v ^* _d , v ^* _q ).

And, switching control signal output unit 530, d, q-axis voltage command value (v ^* _d, v ^* _q) converter switching control signal (Scc) to drive the switching devices in the buck-boost converter 410 on the basis of Can be output. In particular, the first buck switching control signal SS1, the second buck switching control signal SS2, and the boost switching control signal SS3 can be output.

The switching control signal output unit 530 includes a step-down signal generating unit 531 for generating switching control signals SS1 and SS2 for the buck switching devices S1 and S2, And a step-up signal generating unit 533 for generating a switching control signal SS3.

In addition, the switching control signal output section 530 includes a first feedback path synthesis section 537 for outputting the first buck switching control signal SS1 and a second feedback path synthesis section 537 for outputting the second buck switching control signal SS2. And a second return path synthesis unit 539. [

The first return path synthesizing unit 537 and the second return path synthesizing unit 539 generate the return current path in accordance with the positive / negative half period of the input voltage Vin during the step-down operation, And generates and outputs the first and second buck switching control signals SS1 and SS2, respectively.

6A and 6B are views referred to in the description of the operation of FIGS. 4A to 4B.

6A is a diagram referred to explain the operation of the power conversion apparatus 200 including the bridgeless buck-boost converter 410 according to the embodiment of the present invention. FIG. 6B is a diagram illustrating the operation of the bridge diode element (Refer to FIG. 5) for explaining the operation of the power conversion apparatus including the rectification unit 405 having the first, second, third, fourth, fifth, sixth, seventh, eighth,

6A, when the boost switching device S3 is turned on, the input power supply Vin is switched between the first buck switching device S1, the inductor L1, the boost switching mode, Through the element S3 and diode element D2, and the energy is stored in the inductor L1. The stored energy is transferred to the load 205 via the first buck switching element S1, the inductor L1 and the backflow prevention diode element D3 in accordance with the turn-off of the boost switching element S3. do.

6B, when the boost switching device Sb is turned on, the input power supply Vin is switched to the diode device Da, the buck switching device Sa, the inductor La ), The boost switching element Sb, and the diode element Dd, and energy is stored in the inductor La. The buck switching element Sb is turned off and is supplied to the load 205 through the diode element Da, the buck switching element Sa, the inductor La and the reverse current prevention diode element Dr, The stored energy is transferred.

According to the power conversion apparatus of FIG. 6B, since two diode elements (Da, Dr or Dr, Dd) must pass through during the boost mode operation, compared with the case of passing through one diode element (D3 or D2) , Resulting in further power consumption due to the diode element. Therefore, the power conversion efficiency becomes more excellent in comparison with Fig. 6B, and Fig. 6A.

As a result, according to the bridgeless buck-boost converter 410 according to the embodiment of the present invention, the power loss can be reduced by reducing the number of circuit elements on the conduction path in the boost mode.

Fig. 7 is a diagram referred to in the description of the converter operation of Fig. 4A.

7B is a graph showing the relationship between the absolute value of the input AC voltage and the first dc voltage Vdc1, For example. The first dc voltage terminal (Vdc1) may correspond to the detected dc terminal voltage (Vdc) or the dc terminal voltage command value (V ^* dc).

When converter control unit 415, while the amount of the half cycle of the input AC power source (Vin), dc terminal voltage (Vdc) or a dc terminal voltage command value (V ^* dc), is greater than the voltage of the inputted AC power supply (Vin) , buck switching element (S1, S2) of the first switching element (S1) is turned on and the boost switching element (S3) that controls to switch, dc bus voltage (Vdc) or a dc terminal voltage command value (V ^* dc) is The first switching element S1 of the buck switching elements S1 and S2 is switched and the boost switching element S3 is turned off and the buck switching element S1, and S2, the second switching element S2 is turned on.

Accordingly, during the positive half period of the input AC power supply Vin, the dc short voltage Vdc or the dc short voltage instruction value V ^* dc is supplied during a period Ta and Tc during which the voltage is greater than the voltage of the input ac power supply Vin , The first switching element S1 of the buck switching elements S1 and S2 is turned on, and the boost switching element S3 performs PWM switching. At this time, the second switching device S2 is continuously turned on.

On the other hand, during the Tb period in which the dc short-circuit voltage (Vdc) or the dc short-circuit voltage set value (V ^* dc) is smaller than the voltage of the input AC power supply (Vin) The first switching element S1 of the elements S1 and S2 is PWM-switched so that the boost switching element S3 is turned off and the second switching element S2 of the buck switching elements S1 and S2 is controlled. Are turned on.

On the other hand, the converter control unit 415 controls the first switching device S1 of the buck switching devices S1 and S2 to be on during the negative half period of the input AC power supply Vin, The second switching element S2 of the buck switching elements S1 and S2 is turned on and the boost switch element S2 is turned on when the dc step voltage command value V ^* dc is larger than the voltage magnitude of the input ac power source Vin. of (S3) that controls to switch, dc bus voltage (Vdc) or a dc terminal voltage command value (V ^* dc) is, less than the voltage of input AC power source (Vin), a buck switching element (S1, S2) The second switching element S2 is switched and the boost switching element S3 is turned off.

Accordingly, of the negative half cycle of the input AC power source (Vin), dc terminal voltage (Vdc) or a dc terminal voltage command value (V ^* dc) is, large Tc, Te interval than the voltage of input AC power source (Vin) The second switching element S2 of the buck switching elements S1 and S2 is turned on and the boost switching element S3 performs PWM switching. At this time, the first switching device S1 is continuously turned on.

On the other hand, while during negative half cycle of the input AC power source (Vin), dc terminal voltage (Vdc) or a dc terminal voltage command value (V ^* dc) is, small Td period than the voltage of input AC power source (Vin), a buck The second switching element S2 of the switching elements S1 and S2 is PWM-switched and the boost switching element S3 is turned off. At this time, the first switching device S1 is continuously turned on.

That is, the first buck switching control signal SS1, the second buck switching control signal SS2, and the boost switching control signal SS3, as shown in Figs. 7 (c), 7 (d) and 7 , And may be output from the converter control unit 415.

Figs. 8A-8B are diagrams referred to for explaining the boost mode operation of the converter of Fig. 4A.

8A illustrates the operation of the buck-boost converter 410 during a positive half-period of the input ac power supply (Vin) in a boost mode.

First, as shown in FIG. 8A, the first buck switching element S1 and the boost switching element S3 are turned on, and the AC power source Vin, the first buck switching element S1, Energy is stored in the inductor L1 based on the current flowing through the inductor L1, the boost switching element S3, and the diode element D2. At this time, the second buck switching device S2 may be in an on state.

Next, as shown in FIG. 8A, the first buck switching element S1 is turned on and the boost switching element S3 is turned off, so that the AC power source Vin, the first buck switching element S1, the inductor The energy stored in the AC power source Vin and the inductor Ll is supplied to the capacitor C through the capacitor C and the diode D2, And the load 205, respectively. At this time, the second buck switching device S2 may be in an on state.

FIG. 8B illustrates the operation of the buck boost converter 410 during the negative half period of the input AC power supply (Vin) in the boost mode.

First, as shown in Fig. 8B, the second buck switching element S2 and the inductor L3 are turned on in accordance with the on state of the second buck switching element S2 and the boost switching element S3, Energy is stored in the inductor L1 based on the current flowing through the diode L1, the boost switching element S3, and the diode element D1. At this time, the first buck switching device S1 may be on.

Next, as shown in FIG. 8B, the second buck switching element S2 is turned on and the boost switching element S3 is turned off, so that the AC power source Vin, the second buck switching element S2, the inductor The energy stored in the AC power source Vin and the inductor Ll is supplied to the capacitor C through the capacitor C and the diode Dl through the diode Dl, the backflow prevention diode D3, the capacitor C, the load 205, And the load 205, respectively. At this time, the first buck switching device S1 may be on.

Figures 9A-9B are diagrams for the buck mode operation of the converter of Figure 4B.

FIG. 9A illustrates the operation of buck-boost converter 410 during a positive half period of an input AC power supply (Vin) in buck mode.

First, as shown in FIG. 9A, the first buck switching element S1 is turned on and the boost switching element S3 is turned off, so that the AC power source Vin, the first buck switching element S1, the inductor L1 and the reverse current prevention diode D3, the capacitor C, the load 205 and the diode element D2 are conducted and the AC power source Vin is supplied to the capacitor C and the load 205 . Meanwhile, the energy of a part of the AC power source Vin is stored in the inductor L1. At this time, the second buck switching device S2 may be in an on state.

Next, as shown in FIG. 9A, the first buck switching element S1 is turned off, and the second buck switching element S2 and the boost switching element S3 are turned on, The two buck switching elements S2, the inductor L1, the backflow prevention diode D3, the capacitor C, the load 205 and the diode element D2 are conductive and the energy stored in the inductor L1 is, The capacitor C, and the load 205, respectively.

FIG. 9B illustrates the operation of buck-boost converter 410 during a negative half period of an input AC power supply (Vin) in buck mode.

First, as shown in FIG. 9B, the second buck switching element S2 is turned on and the boost switching element S3 is turned off, so that the AC power source Vin, the second buck switching element S2, the inductor L1 and the reverse current prevention diode D3, the capacitor C, the load 205 and the diode element D1 are conducted and the AC power source Vin is supplied to the capacitor C and the load 205 . Meanwhile, the energy of a part of the AC power source Vin is stored in the inductor L1. At this time, the first buck switching device S1 may be on.

Next, as shown in FIG. 9B, the second buck switching element S2 is turned off, and the first buck switching element S1 and the boost switching element S3 are turned on, The one-buck switching element S1, the inductor L1, the backflow prevention diode D3, the capacitor C, the load 205 and the diode element D1 are conductive and the energy stored in the inductor L1, The capacitor C, and the load 205, respectively.

10 is a diagram referred to for explaining the operation of the converter of FIG. 4A according to the dc voltage.

Referring to the drawings, the dc voltage terminal Vdc or the dc voltage terminal voltage command V ^* dc, which is the voltage across the capacitor Vdc, can have various levels.

Converter control unit 415, dc bus voltage (Vdc) or a dc the terminal voltage command value (V ^* dc) is, greater than the voltage of the inputted AC power supply (Vin), the boost switch to operate in the boost mode, the device (S3) And controls the buck switching device to switch to operate in the buck mode when the dc short voltage Vdc or the dc short voltage set value V ^* dc is smaller than the voltage of the input ac power supply Vin.

On the other hand, the converter control section 415 turns on the buck switching element so that the dc terminal voltage Vdc or the dc step voltage command value is larger than the peak value of the input AC power supply Vin so that the buck switching element is turned on, The element S3 is controlled to switch.

For an operation of converter control unit 415, in the figure, dc is the terminal voltage (Vdc) or a dc terminal voltage command value (V ^* dc), illustrated separately in the case of a large voltage of Vdc2 than in the case Vdc1 is, Vdc1 .

The case where the dc step voltage (Vdc) or the dc step voltage command value (V ^* dc) is Vdc1 is the same as that in Fig. 7, and a description thereof will be omitted. That is, Figs. 7B to 7E correspond to Figs. 10A to 10D.

On the other hand, as shown in (e) of Figure 10, dc terminal voltage (Vdc) or a dc terminal voltage command value (V ^* dc) is, in the case of Vdc2, dc terminal voltage (Vdc) or a dc terminal voltage command value, the input AC power source The converter control section 415 controls the buck switching elements S1 and S2 to turn on and the boost switching element S3 to PWM switch so that the converter control section 415 continuously operates in the boost mode. In the drawing, the boost switching device S3 is PWM-switched during the Tx period.

As a result, the converter control unit 415 outputs the first buck switching control signal SS1, the second buck switching control signal SS2 and the boost switching control signal SS3 as shown in Figs. 10F to 10H Can be output.

Fig. 11 illustrates a circuit diagram of an inverter in the power converter of Fig. 3;

The inverter 420 includes a pair of upper arm switching elements Sa, Sb and Sc and lower arm switching elements S'a, S'b and S'c serially connected to each other, The switching elements are connected to each other in parallel (Sa & S a, Sb & S'b, Sc & S'c). Diodes are connected in anti-parallel to each switching element Sa, S'a, Sb, S'b, Sc, S'c.

The switching elements in the inverter 420 perform ON / OFF operations of the respective switching elements based on the inverter switching control signal Sic from the controller 430. [

The inverter 420 drives the motor 250 by converting a DC power supply across the capacitor C to an AC power supply in the motor 250 operating mode.

The inverter control unit 430 can control the operation of the switching element in the inverter 420. [ To this end, the drive controller 430, it is possible to input the output current detector (E in Fig. 11) output current (i _o) detected by the.

The inverter control unit 430 outputs the inverter switching control signal Sic to the inverter 420 to control the switching operation of the inverter 420. [ Inverter switching control signal (Sic) is a switching control signal of a pulse width modulation (PWM), the output current detection section is output is generated and based on the output current (i _o) detected from (E in Fig. 11).

The output current detection section (E in FIG. 11) can detect the output current (i ₀ ) flowing between the inverter 420 and the three-phase motor 250. That is, the current flowing in the motor 250 is 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 detection unit E may be located between the inverter 420 and the motor 250. For current detection, a current transformer (CT), a shunt resistor, or the like may be used.

Three shunt resistors are placed between the inverter 420 and the synchronous motor 250 or the three lower arm switching elements S'a, S'b, S'c To be connected to each other. On the other hand, it is also possible to use two shunt resistors using three phase equilibrium. On the other hand, when one shunt resistor is used, the shunt resistor may be disposed between the capacitor C and the inverter 420 described above.

The detected output current (i _o) are, as discrete signals (discrete signal) of the pulse type, may be applied to the controller 430, it is by the inverter switching control signal (Sic) based on the detected output current (i _o) . In the output current detection (i _o) will now be described in that the three-phase output currents (ia, ib, ic) of the.

12 is an internal block diagram of the inverter control unit of Fig.

12, the inverter control unit 430 includes an axis conversion unit 310, a position estimation unit 320, a current command generation unit 330, a voltage command generation unit 340, an axis conversion 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 추정할 수 있다. 또한, 위치 추정부(320)는, 회전자 위치(

)에 기초하여, 속도(

)를 추정할 수도 있다. The position estimating unit 320 calculates the position of the rotor 250 of the motor 250 based on the two-phase currents id and iq of the rotational coordinate system converted by the axis conversion unit 310

) Can be estimated. Further, the position estimating unit 320 estimates the position of the rotor (

), The speed

).

)와 연산된 속도(

)를 출력할 수 있다.As a result, the position estimating unit 320 estimates the current position (ia, ib, ic) based on the three-phase output currents ia, ib, ic detected by the output current detecting unit E

) And 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(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 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 335 performs 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 344 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 . 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 , 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 0 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 position estimating 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 position estimating unit 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 350 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.

The output inverter switching control signal Sic may be converted into a gate driving signal in a gate driving unit (not shown) 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.

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

The method for operating the charging apparatus of the present invention can be implemented as a code that can be read by a processor on a recording medium readable by a processor included in the charging apparatus. The processor-readable recording medium includes all kinds of recording apparatuses in which data that can be read by the processor is stored.

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 (15)

A buck-boost converter that converts input AC power to direct current power and operates in at least one of a buck mode or a boost mode;
And a converter control unit for controlling the buck-boost converter,
Wherein the buck-
An upper buck switching element and a lower diode element bridged with each other;
A boost switching device; And
And an inductor connected between the buck switching device and the boost switching device. The method according to claim 1,
Wherein the buck-
Wherein in the boost mode, energy is stored in the inductor based on a current flowing through the ac power source, the buck switching element, the inductor, the boost switching element, and the diode element,
Wherein in the buck mode, energy stored in the inductor is consumed based on a current flowing through the buck switching element, the inductor, and the diode element. The method according to claim 1,
And a capacitor connected to an output terminal of the buck-boost converter,
The converter control unit includes:
Wherein the buck switching element and the boost switching element are controlled based on a dc step voltage or a dc step voltage command value at both ends of the capacitor. The method of claim 3,
The converter control unit includes:
And controls the boost switching device to switch to operate in the boost mode when the dc step voltage or the dc step voltage command value is greater than the voltage of the input AC power,
And controls switching of the buck switching device so as to operate in the buck mode when the dc step voltage or the dc step voltage command value is smaller than the voltage of the input ac power source. The method of claim 3,
The converter control unit includes:
During a positive half period of the input AC power,
Wherein the first switching element of the buck switching element is turned on and the boost switching element is controlled to be switched when the dc step voltage or the dc step voltage command value is greater than the voltage of the input AC power source,
Wherein the first switching device is switched and the boost switching device is turned off when the dc step voltage or the dc step voltage command value is smaller than the voltage of the input AC power source,
And the second switching element of the buck switching element is controlled to be turned on. The method of claim 3,
The converter control unit includes:
During a negative half period of the input AC power,
Wherein the first switching element of the buck switching element is controlled to be on,
Wherein when the dc step voltage or the dc step voltage command value is larger than the voltage of the input AC power source, the second switching device of the buck switching device is turned on and controls the boost switching device to switch,
Wherein the second switching element is switched and the boost switching element is turned off when the dc step voltage or the dc step voltage command value is smaller than the voltage of the input AC power source. Conversion device. The method of claim 3,
The converter control unit includes:
Wherein the buck switching element is turned on and the boost switching element is switched so as to operate in the boost mode when the dc step voltage or the dc step voltage command value is larger than the peak value of the AC power inputted thereto Power conversion device. The method according to claim 1,
Wherein the inductor is commonly used in the buck mode and the boost mode. The method according to claim 1,
The buck switching device includes:
And in the buck mode, provides a return current path for the inductor. The method according to claim 1,
The converter control unit includes:
A current command generator for generating a current command value based on a dc terminal voltage that is an output voltage of the bridgeless converter;
A voltage command generator for generating a voltage command value based on the current command value and the current flowing in the inductor; And
And a switching control signal output unit for outputting a switching control signal based on the voltage command value. 11. The method of claim 10,
Wherein the switching control signal output unit comprises:
A step-down signal generator for generating a switching control signal for the buck switching element; And
And a boost signal generator for generating a switching control signal for the boost switching element. A buck-boost converter that converts input AC power to direct current power and operates in at least one of a buck mode or a boost mode;
And a converter control unit for controlling the buck-boost converter,
Wherein the buck-
A buck switching device performing switching in the buck mode;
A boost switching element for performing switching in the boost mode,
An inductor connected between the buck switching element and the boost switching element,
And a diode element for rectifying the AC power,
Wherein in the boost mode, energy is stored in the inductor based on a current flowing through the ac power source, the buck switching element, the inductor, the boost switching element, and the diode element,
Wherein in the buck mode, energy stored in the inductor is consumed based on a current flowing through the buck switching element, the inductor, and the diode element. compressor;
And a power conversion unit for supplying driving power to the motor in the compressor,
Wherein the power conversion unit comprises:
A buck-boost converter that converts input AC power to direct current power and operates in at least one of a buck mode or a boost mode;
And a converter control unit for controlling the buck-boost converter,
Wherein the buck-
An upper buck switching element and a lower diode element bridged with each other;
A boost switching device; And
And an inductor connected between the buck switching device and the boost switching device. 14. The method of claim 13,
Wherein the power conversion unit comprises:
And a capacitor connected to an output terminal of the buck-boost converter,
The converter control unit includes:
Wherein the buck switching element and the boost switching element are controlled based on a dc step voltage or a dc step voltage command value at both ends of the capacitor. 15. The method of claim 14,
The converter control unit includes:
And controls the power conversion unit to switch the boost switching device to operate in the boost mode when the dc step voltage or the dc step voltage instruction value is greater than the voltage of the input AC power source,
Wherein the buck switching device is controlled to switch the buck switching device so that the power converting part operates in the buck mode when the dc step voltage or the dc step voltage command value is smaller than the voltage of the AC power inputted thereto.

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