KR20060113365A - Compressor driving unit and refrigerator using the same - Google Patents

Abstract

A reciprocation type compressor driving unit free from start failure. A position established by moving (Theta init) about 45° in a direction of rotation is the best start initial position with a line connecting a piston (107)-compression upper dead point-lower dead point in a reciprocation type compressor (15) taken as a reference; therefore, as start motor constants for moving a rotor (117) to this start initial position, a rotation initial position (Theta init), a start acceleration speed (omega init), a start d-axis current (I dinit), and a start q-axis current (I qinit) are set. Before starting, a drive current is passed through one phase of a compressor motor (28) on the basis of the start motor constants, with the position of the rotor (117) being caused to stand by at the start initial position. Thereafter, starting is initiated from this start initial position, whereby normal starting can be effected with the rotor (117) being in either start position.

Description

Compressor Driving Device and Refrigerator Using the Same {COMPRESSOR DRIVING UNIT AND REFRIGERATOR USING THE SAME}

The present invention relates to a compressor driving apparatus for driving a compressor motor by an inverter circuit.

Conventionally, a receiver type compressor is used as a drive source of the compressor of a refrigerator.

As a compressor of this kind, a crank is extended from a crank pin integrated with a rotational shaft of a motor to connect the crank and the piston accommodated in the cylinder chamber through a ball joint mechanism portion, and the ball joint mechanism portion is integrally provided at the end of the crank. And a ball base installed in the piston and slidingly holding the ball freely, and rotating the motor to retaliate the piston in the cylinder chamber to compress the refrigerant (for example, JP 2003-214343). Reference).

By the way, when controlling the motor of such a compressor, it is necessary to detect the position of the rotor of the motor. Therefore, if a position detecting element such as a ball IC is used, the position of the rotor can be reliably detected, but it is expensive. Therefore, in normal inverter control, since it starts by two-phase energization, the sensorless control which can detect a position by the induced electric power which generate | occur | produced by the other one phase which does not energize is performed.

In vector control, however, the three phases are energized simultaneously and the position of the rotor is detected by the shunt resistor. Therefore, the rotor of the motor is not accurately positioned until the predetermined speed is reached at the start of the motor. After the predetermined speed is reached, speed control is started.

However, the 6-slot 4-pole brushless DC motor has two electrical control positions with 180 ° symmetry during the rotation of the motor (1). There is a problem that unknown.

In addition, since the compressor performs the compression operation by the piston by one rotation, the torque applied to the rotor is always changed by the position during rotation. Therefore, when the compressor is started in a state where there is a pressure difference between the suction port and the discharge port of the compressor, there is a problem that the startup rarely fails.

Therefore, the present invention provides a drive device for a compressor without starting failure to solve the above problem.

The invention according to claim 1 includes a refrigerating compressor rotating at a three-phase brushless DC motor, a refrigeration cycle having at least a condenser and an evaporator, and compressing a refrigerant by the compressor to cool the evaporator. An inverter circuit for supplying a three-phase driving current to the stator coil of the brushless DC motor, a PWM circuit for supplying a PWM signal to the inverter circuit, a drive current detecting means for detecting the three-phase driving current, and the three-phase detected Dq converting means for converting the d-axis current, which is a current component corresponding to the magnetic flux of the rotor of the brushless DC motor, and the q-axis current, which is a current component corresponding to the torque of the brushless DC motor, based on a drive current; Control means for outputting a reference q-axis current and a reference d-axis current based on one d-axis current and q-axis current and a speed command signal input from the outside; Voltage conversion means for converting the reference q-axis current and the reference d-axis current into a reference q-axis voltage and a reference d-axis voltage, converting the converted reference q-axis voltage and the reference d-axis voltage into a three-phase voltage to the PWM circuit. Rotating the rotor of the brushless DC motor to the initial position of the three-phase conversion means for outputting, the position rotated from 40 ° to 50 ° based on the line connecting the position of the piston of the compressor and compression top dead center and bottom dead center. And an initial pattern output means for moving and a starting means for starting the compressor at the initial starting position.

The invention according to claim 2 is according to claim 1,

The brushless DC motor is a compressor driving device, characterized in that the three-phase four-pole.

The invention according to claim 3 is according to claim 1,

And the starting initial position is a position rotated by 45 ° with reference to a line connecting the position of the piston and the compression top dead center and the bottom dead center.

The invention according to claim 4 is at least one of claims 1 to 3,

The refrigeration cycle is a compressor driving device, characterized in that the refrigeration cycle of the refrigerator.

According to the present invention, the compressor can be started even when there is a pressure difference between the inlet and the outlet of the compressor during startup by a sine wave inverter by moving to a starting initial position of the rotor of the brushless DC motor at the start of the compressor. Cycle control is possible.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal front view of the compressor which is a receiver type sealed type of one Embodiment of this invention,

2 is a view for explaining the position of the top dead center of the compression mechanism of the present embodiment;

3 is a view for explaining the position of the bottom dead center of the compression mechanism of the present embodiment;

4 is an explanatory diagram of a compmotor;

5 is a graph showing the probability of success for θ init in the present embodiment,

6 is a cross-sectional view of the refrigerator showing the present embodiment;

7 is a refrigeration cycle of the refrigerator of the present embodiment;

8 is a block diagram of a refrigerator of the present embodiment;

9 is a vector diagram for executing αβ change in three phases and

10 is a vector diagram for performing a dq change in αβ.

Hereinafter, the refrigerator 1 of one Embodiment of this invention is demonstrated.

(1) Configuration of the Refrigerator 1

First, the structure of the refrigerator 1 is demonstrated based on FIG. 6 and FIG.

6 is a cross-sectional view of the refrigerator 1 showing the present embodiment, and FIG. 7 is a refrigeration cycle of the refrigerator 1.

The cabinet of the refrigerator 1 is formed of a heat insulating box 9 and an inner box 8, and is divided into a refrigeration temperature band 30 and a freezing temperature band 31 by the heat insulation partition wall 2, and the two temperatures. The cold air in the zones 30 and 31 is completely independent, and each cold air is not mixed.

The refrigerator in the refrigerator temperature zone 30 is divided into a refrigerator compartment 4 and a vegetable compartment 5 by a refrigerated partition plate 3, and the inside of the freezer in the freezer temperature zone 31 is a first freezer compartment 6 and a second freezer compartment. It consists of (7), and each chamber is equipped with the opening door 4a, 5a, 6a, 7a, respectively. In the cold storage chamber 4, a temperature sensor (hereinafter referred to as R sensor) 34 and a deodorizer 35 for detecting the internal temperature of the refrigerator are arranged.

The refrigerator compartment evaporator 10 and the refrigerator compartment cooling fan 11 are arrange | positioned at the back of the vegetable compartment 5, The refrigerator compartment cooling fan 11 is operated arbitrarily by the temperature change of a refrigerator or door opening and closing. The rear surface of the refrigerating storage chamber 4 is a cold air circulation path 18 for supplying cold air into the refrigerating temperature zone 30. Defrost heater 26 is disposed under the freezer compartment evaporator 12.

The freezer compartment evaporator 12 and the freezer compartment cooling fan 13 are arranged on the back walls of the first and second freezer compartments 6 and 7, and the first and second freezer compartments 6 and 7 are cooled by circulating cold air.

As shown in FIG. 7, a compressor 15 and a condenser 21 are respectively arranged in the machine room 14 below the rear wall of the refrigerator 1, and the combustible refrigerant discharged from the compressor 15 is After passing through the condenser 21, the refrigerant flow paths are switched with each other by the refrigerant switching mechanism of the switching valve 22 to realize the freezing mode and the refrigeration mode.

The refrigerating capillary tube 23 and the refrigerating chamber evaporator 10 are sequentially connected to one outlet of the switching valve 22, and the refrigerating capillary tube 24 and the freezing chamber evaporator 12 are connected to the other outlet of the switching valve 22. In turn, the accumulator 16 is connected to the freezer compartment evaporator 12.

According to the refrigerator 1 having the above-described configuration, the refrigerant flow path is switched by the switching valve 22, and in the freezing mode at the time of cooling the freezing temperature band 31, the combustible refrigerant is depressurized in the freezing capillary tube 24 to freeze the chamber evaporator. After entering (12) to cool the freezing temperature zone (31), it returns to the compressor (15) again.

On the other hand, in the refrigerating mode at the time of cooling the refrigerating temperature zone 30, the combustible refrigerant is decompressed in the refrigeration capillary tube 23, enters the refrigerating chamber evaporator 10 to cool the refrigerating temperature zone 30, and then the freezer compartment evaporator 12 ) To configure the refrigeration cycle back to the compressor (15).

In the freezing mode, the combustible refrigerant flows in the order of the refrigeration capillary tube 24, the freezer compartment evaporator 12, and the accumulator 16, and the cold air is circulated in the freezer by the operation of the freezer compartment cooling fan 13, and the first and the Cooling of the second freezing chambers 6 and 7 is performed.

In the refrigerating mode, when the switching valve 22 is switched and the refrigerant passage is switched from the freezing temperature band 31 side to the freezing temperature band 30 side, the combustible refrigerant flows to the refrigerating chamber evaporator 10, and the By the operation, the refrigerating compartment 4 and the vegetable compartment 5 are cooled.

(2) Structure of the electric system of the refrigerator (1)

The structure of the electric system of the refrigerator 1 is demonstrated based on the block diagram of FIG.

As shown in FIG. 8, a three-phase brushless DC motor (hereinafter referred to as a comp motor) 28 for driving the compressor 15 and a driving device for driving the comp motor 28 (hereinafter referred to as a comp driving device) 32) and a main control portion 33 of the refrigerator 1 for controlling the comp driving device 32. In addition, the main control part 33 is connected with the door switches 4b-7b respectively provided in the doors 4a-7a of each compartment 4, 5, 6, 7. In addition, the main control part 33 is connected with the deodorizer 35, the defrost heater 26, and the R sensor 34. As shown in FIG.

First, the structure of the comp driving device 32 will be described.

The comp driving device 32 includes an inverter circuit 42, a rectifier circuit 44, an AC power supply 46, a PWM forming unit 48, an AD converter 50, a dq converter 52, and a speed detector 54. ), Speed command output section 56, speed PI control section 58, q-axis current PI control section 60, d-axis current PI control section 62, three-phase conversion section 64, initial pattern output section 66 Consists of.

The compressor motor 28 which rotates the compressor 15 is a three-phase brushless DC motor as mentioned above. The inverter circuit 42 causes the three-phase driving current to flow through the stator coils 40u, 40v, and 40w of the three phases (u phase, v phase, w phase) of the comp motor 28.

The inverter circuit 42 is a full bridge inverter circuit composed of transistors Tr1 to Tr6 which are six power switching semiconductors. Although not shown in the figure, a diode is connected in reverse with respect to the switching transistors Tr1 to Tr6. In addition, a detection resistor R1 for detecting a drive current in series with the switching transistors Tr1 and Tr4 is connected, a detection resistor R2 is connected in series with the switching transistors Tr2 and Tr5, and is connected in series with the switching transistors Tr28 and Tr6. The detection resistor R28 is connected.

The rectifier circuit 44 is supplied with an AC voltage from an AC power supply 46, which is a commercial power supply (100V AC), and rectified and supplied to the inverter circuit 42.

The PWM forming unit supplies a PWM signal to the gate terminals of the six switching transistors Tr1 to Tr6. The PWM forming unit 48 performs pulse width modulation on the basis of the three-phase voltages Vu, Vv, and Vw described later, and turns on / off each of the switching transistors Tr1 to Tr6 at a predetermined timing.

The AD converter 50 detects the voltage value at the shunt resistors R1, R2, and R28, converts the voltage value of each phase from an analog value to a digital value, and outputs three-phase driving currents Iu, Iv, and Iw. do.

The dq converting unit 52 converts the driving currents Iu, Iv, and Iw output from the AD converting unit 50 into the current (Id) of the d-axis (direct-axis) corresponding to the magnetic flux and the comp motor 28. Is converted into a current Iq of a quadrature-axis, which is a current component corresponding to the torque of.

The conversion method converts three phases Iu, Iv and Iw into two phases Iα and Iβ, as shown in Equation (1). 9 is a vector diagram showing a relationship between the three-phase current and the two-phase current.

Next, the two-phase currents Iα and Iβ converted as described above are converted to the q-axis current Iq and the d-axis current Id by using Equation (2). The relationship between the drive current of the two phases and the converted q-axis current Iq and d-axis current Id has the same relationship as the vector diagram shown in FIG.

The speed detection unit 54 detects the rotation angle θ and the rotation speed? Of the comp motor 28 based on the detected q-axis current Iq and d-axis current Id. Based on the q-axis current and the d-axis current, the rotation angle θ which is the position of the rotor of the comp motor 28 is obtained, and the rotation speed ω is obtained by differentiating the θ.

The main controller 33 of the refrigerator 1 outputs the speed command signal S based on the q-axis current Iq sent from the dq converter 52.

The speed command output section 56 outputs a reference rotation speed ω ref based on the speed command signal S at the main control section 33 and the rotation speed ω at the speed detection section 54. The reference rotation speed ω ref is input to the speed PI control unit 58 together with the current rotation speed ω.

The speed PI control unit 58 performs PI control based on the difference between the reference circuit speed ω ref and the current rotation speed ω, and performs the reference q-axis current Iq ref and the reference d-axis current Id ref. Are output to the q-axis current PI controller 60 and the d-axis current PI controller 62 together with the current q-axis current Iq and the current d-axis current Id, respectively.

The q-axis current PI control unit 60 executes PI control, performs current / voltage conversion, and outputs a reference q-axis voltage Vq.

The d-axis current PI controller 62 executes PI control, performs current / voltage conversion, and outputs a reference d-axis voltage Vd.

The three-phase conversion unit 64 first converts the reference d-axis voltage Vd and the reference q-axis voltage Vq into two-phase voltages based on Equation (3).

The converted two-phase voltages Vα and Vβ are converted into three-phase voltages Vu, Vv and Vw based on Equation 4.

The converted three-phase voltages Vu, Vv, and Vw are output to the PWM forming unit 48.

According to the comp driving device 32 of the present embodiment, the rotational speed is detected based on the detected d-axis current Id and q-axis current Iq, and the rotational speed? Feedback control is executed based on S), and the PWM circuit 48 converts the PWM signal to the inverter circuit 42 so that the comp motor 28 rotates at a rotational speed ω ref suitable for the speed command signal S. Will output The inverter circuit 42 outputs the three-phase drive current to the three-phase stator coil 40 of the comp motor 28 based on this.

In the initial pattern output section 66, the starting motor constant when the compressor 15 is started is set, and the starting characteristic is determined by the set starting motor constant when starting. The starting motor constants set are the initial rotational position (θ init), the starting acceleration speed (ω init), the starting d-axis current (I dinit), the starting q-axis current (I qinit), and the starting acceleration speed (ω init) is Output to the speed command output section 56, the initial rotation position (θ init) is output to the dq converter 52, the starting d-axis current (I dinit), the starting q-axis current (I qinit) is the speed PI control unit The output is 58. The control at the start will be described later.

(3) The structure and operation state of the compressor 15

(3-1) Structure of Compressor 15

Next, the structure of the receiver-type hermetic compressor 15 is demonstrated based on FIGS.

1 is a front view with the compressor 15 in the longitudinal section.

The refrigerant, which is a compressed fluid, is isobutane (R600a), which is a natural combustible refrigerant as described above.

The frame 102 is elastically supported by the spring 102a at the substantially middle part of the up-down direction in the vertical sealed box 101 of the compressor 15. The compression mechanism part 103 is provided in the upper side of the frame 102, and the compressor motor 28 is provided in the lower side. As the compression mechanism 103, a so-called receiver type compression mechanism is adopted.

A hole 102b for extraction is provided along the center of the frame 102, and the rotary shaft 105, which is the main shaft, is fitted with each other so that rotation is free. An upper edge portion of the rotary shaft 105 is integrally provided with an edge portion 105a, which is placed on the upper surface of the frame 102 so as to be free to slide, and an upper portion of the edge portion 105a is different from the central axis of the rotary shaft 105. Crank pins 105b having a central axis eccentrically predetermined amount are provided in series. Therefore, when the rotary shaft 105 is driven to rotate, the edge portion 105a rotates in a contact state on the upper surface of the frame 102, and the crank pin 105b is eccentric along the periphery of the center of the rotary shaft 105. Rotate

The compression mechanism part 103 is provided in the upper surface of the frame 102, and is provided with the cylinder 106 which made the axial direction horizontal. The inside of the cylinder 106 is a cylinder chamber 108 in which the piston 107 is accommodated so as to freely reciprocate. One end of the crank 109 is connected to the piston 107 via the ball joint mechanism part 110. The other end of the crank 109 is provided with an end portion 111 fitted to each other so as to freely rotate the crank pin 105b.

The ball joint mechanism part 110 is demonstrated. One end of the crank 109 is provided with a ball 112 integrally. On the other hand, the ball holder 113 is provided inside the piston 107. The ball support 113 wraps and maintains the ball 112 so that rotational movement is free. As a result, the crank 109 can move the ball joint mechanism 110 to the point according to the eccentric rotation of the crank pin 105b, and the piston 107 reciprocates in the cylinder 106. do.

In addition, the open end of the cylinder 106 is closed by the valve mechanism 115 and is further covered with the valve cover 116. The valve cover 116 is provided with a partition portion for dividing the interior into two, one space of which is a suction chamber, and the other space of which is a discharge chamber.

The valve mechanism 115 is provided with a valve plate having a suction port and a discharge port, and each suction port and the discharge port are opened and closed by the suction valve and the discharge valve. The suction port faces the suction chamber, and the discharge port faces the discharge chamber.

The compressor motor 28 has a rotor 117 and a circumferential surface of the rotor 117 inserted into a portion protruding downward from the frame 102 of the rotary shaft 105 with respect to the compression mechanism 103 formed in this manner. It consists of a stator 118 having an inner circumferential surface having a narrow gap therebetween and fixed vertically by means of an appropriate means in the frame 102.

(3-2) Structure of Compmotor 28

As shown in Fig. 4, the comp motor 28 is a brushless DC motor, which is a three-phase six-slot four-pole motor. That is, the four-pole rotor 117 rotates on the inner circumferential side of the stator 118 of the three-phase six slot.

When a voltage is applied to each phase of the comp motor 28 by the comp driving device 32, the same control is performed in the motor by 180 ° symmetry. Also, as shown in Fig. 2, when the crank 109 flows a current in three phases in the positioning at the time of starting for one place, the crank 109 is either 180 ° symmetrical by the stop position. Go to the application (FIGS. 2, 3).

(3-3) Operation state of the compressor 15

Next, the compression operation of the compressor 15 and the refrigeration cycle operation according to it will be described.

When the rotary shaft 105 is rotated by energizing the comp motor 28, the crank pin 105b integrally rotates. According to the eccentric rotation, the piston 107 reciprocates in the cylinder chamber 108 through the crank 109 and the ball joint mechanism part 110.

The sealed box 101 is filled with a refrigerant gas evaporated by the evaporator to lower the pressure. The refrigerant gas is guided to the suction chamber in the valve cover 116 and is also sucked into the cylinder chamber 108 of the cylinder 106 in accordance with the movement (reciprocating movement) of the piston 107.

The refrigerant gas is compressed by the piston 107 moving in the reverse direction (restoration motion). When the piston 107 moves to the so-called top dead center position, the discharge valve is opened, and the refrigerant gas compressed and compressed in the cylinder chamber 108 is discharged to the discharge chamber of the valve cover 116.

The pressurized refrigerant gas is led to the external refrigerant pipe from the sealed box 101 through the discharge pipe in the box and guided to the refrigeration cycle. While the rotating shaft 105 continues to rotate, the piston 107 moves and the refrigerating cycle is repeated.

As shown in Fig. 2 and Fig. 3, the crank pin 105b rotates eccentrically with the rotation of the rotary shaft 105, and the center P of the crank pin 105b has a circular rotational track whose eccentricity is the radius of rotation. Draw (A). The crank 109 achieves a flow movement having a predetermined flow angle α, and the ball 112 and the ball receiver 113 slide with each other in the ball joint mechanism 110.

When compressing the refrigerant gas introduced into the cylinder chamber 108, a load F is applied to the upper surface of the piston 107, and the force acts on the ball joint mechanism 110 through the piston 107.

(4) Control method at start

The start of the compressor 15 is energized for a predetermined time (for example, 3 seconds) to start the start by moving the rotor to a predetermined position. In this case, which one is 180 degrees symmetrical for the four-pole rotor 117 is changed by the stop position of the rotor 117.

Therefore, it is necessary for the rotor 117 to be able to start normally at either starting position. When accelerating with a predetermined acceleration at the start, the starting position of the rotor 117 is changed so that the speed at the position where the most torque is put into the compression operation is changed, so that the torque exceeds the maximum point. It is necessary to control. In general, in vector control, it is preferable to start the engine after the pressure difference between the suction port and the discharge port of the compressor 15 disappears, but the pressure difference (for example, 300 Pa) needs to execute the startup. That is, even when there is a pressure difference between the suction port and the discharge port of the compressor 15, the compressor 15 can start normally, and it is necessary to perform optimal refrigeration cycle control.

Therefore, as the optimum position in the above-mentioned start, in this embodiment, the init is rotated by 45 degrees with reference to the line connecting the piston 107-compression top dead center-bottom dead center. Hereinafter, the position which rotated 45 degrees from the position of top dead center or bottom dead center is called a "start initial position." The reason why the position is optimal is 0 ° as shown in Fig. 5, while the torque is minimum at the bottom dead center, but the torque is maximum at the top dead center, and the rotor 117 stops at the top dead center. If there is a high probability of starting failure, and the torque is still large at 30 ° or 60 °, the position of 45 ° has the highest probability of success.

The starting initial positions exist at two positions of 180 ° symmetry, as shown in FIGS. 2 and 3. 2 and 3 are schematic plan views of a part of the compression mechanism 103 in the cross section, and the eccentric rotation of the crank pin 105b and the flow movement of the crank 109 and the ball joint mechanism 110 accordingly. And the relationship with the piston 107. 2 and 3, the compression top dead center is at 0 °, and the bottom dead center is at 180 °. FIG. 2 is a position where the crank 109 is rotated 45 ° from compression top dead center, and FIG. 3 is a position where crank 109 is rotated 45 ° from bottom dead center.

Then, the rotational position of the rotor 117 when the crank 109 is at the top dead center and the rotational position of the rotor 117 when the crank 109 is at the bottom dead center correspond to each other. Is energized to at least one phase of each phase of the compmotor 28 so that the rotational position of the rotor 117 is rotated by 45 ° from the top dead center (see FIG. 2) and rotated 45 ° from the bottom dead center. The start motor constant is set in advance so as to stop at the position (see Fig. 3). That is, the starting motor constant (θ init), starting acceleration speed (ω init), starting d-axis current (I dinit), starting q-axis current (I) as starting motor constants for moving the rotor 117 to the starting initial position. qinit) is set in advance in the initial pattern output section 66.

As described above, the comp drive device 32 causes a drive current to flow into the comp motor 28 at least one phase based on the start motor constant before the compressor 15 is started, and the rotor 117. Wait for the position of) to the initial starting position. Thereafter, the motor is started at the starting initial position by rotating at a starting rotational speed (for example, 40 kPa) to start in a state where the starting torque is small, and the rotor 117 is normal at either starting position. Can be started.

In addition, if there is no pressure difference between the inlet and outlet of the compressor 15, the rotational speed may be too high to start the operation, so the starting rotational speed may be decreased (for example, 40 kPa lowered to 10 kPa to 30 kPa). If the initial starting position is rotated by only 10 ° or 60 ° instead of 45 ° to make the torque almost heavy, the rotation speed is not too fast and the start does not fail.

(5) Modification example

In the above embodiment, the rotational position of the rotor 117 stops at a position rotated by 45 ° from the top dead center (see Fig. 2) and a position rotated by 45 ° from the bottom dead center (see Fig. 3) as the starting initial position. If it is not limited to this, if it is a range of 40 degrees-50 degrees, it can start reliably.

In addition, in the said embodiment, although demonstrated as the flammable refrigerant | coolant, you may be a nonflammable refrigerant | coolant.

In addition, although the compressor 15 of the said embodiment demonstrated by the ball joint type, it is not limited to this, If it is a receiver type which a piston moves, another structure may be sufficient.

The drive device of the compressor of the present invention can be used for a compressor of a domestic refrigerator or an air conditioner.

Claims (4)

A compressor driving apparatus comprising a refrigerating compressor, a condenser, and a refrigerating cycle having at least a revolving compressor rotating in a three-phase brushless DC motor, wherein the refrigerant is compressed by the compressor to cool the evaporator. An inverter circuit for supplying three-phase driving current to the stator coil of the brushless DC motor; A PWM circuit for supplying a PWM signal to the inverter circuit; Drive current detection means for detecting drive currents of the three phases; On the basis of the detected three-phase drive current, the d-axis current which is a current component corresponding to the magnetic flux of the rotor of the brushless DC motor and the q-axis current which is a current component corresponding to the torque of the brushless DC motor are converted. dq conversion means, Control means for outputting a reference q-axis current and a reference d-axis current based on the converted d-axis current and q-axis current and a speed command signal input from the outside; Voltage conversion means for converting the reference q-axis current and the reference d-axis current into a reference q-axis voltage and a reference d-axis voltage; Three-phase conversion means for converting the converted reference q-axis voltage and the reference d-axis voltage into a three-phase voltage and outputting the same to the PWM circuit; An initial pattern output means for rotating the rotor of the brushless DC motor at a starting initial position which is rotated from 40 ° to 50 ° based on a line connecting the position of the piston and the compression top dead center and the bottom dead center of the compressor; , And a starting means for starting the compressor at the starting initial position. The method of claim 1, And the brushless DC motor is a three-phase four-pole. The method of claim 1, And the starting initial position is a position rotated by 45 ° with reference to a line connecting the position of the piston and the compression top dead center and the bottom dead center. The refrigerator which used the drive apparatus of the compressor in any one of Claims 1-3.

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