KR101886049B1 - Apparatus for controlling compressor and air conditioner having the same - Google Patents

Abstract

A compressor control device and an air conditioner including the same are disclosed. Embodiments of the present invention solve the time delay problem of a disturbance observer by providing a delay compensator in a system having a constant load pattern. The embodiments of the present invention reduce the speed ripple caused by the time delay of the disturbance observer by using a delay compensator in an apparatus for controlling a compressor using a load torque by estimating a load torque using a disturbance observer . Embodiments of the present invention compensate for the phase of the load torque estimated using the time delay according to the speed, so that the load compensation is made at the proper timing, and the speed ripple is minimized.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a compressor control apparatus and an air conditioner including the compressor control apparatus,

The present invention relates to a compressor control apparatus for compensating a current command using a disturbance observer and an air conditioner including the same.

In general, an air conditioner includes a compressor for compressing a refrigerant to a high temperature and a high pressure, a condenser for converting high temperature and high pressure refrigerant transferred from the compressor into a liquid state of low temperature and high pressure by exchanging heat with ambient air, An evaporator for evaporating the refrigerant transferred through the expansion valve or the low temperature low pressure refrigerant transferred from the capillary to depressurize the surrounding heat to maintain the external temperature at a low temperature, An accumulator for filtering refrigerant in a liquid state from the refrigerant gas vaporized in the evaporator and allowing the refrigerant to flow into the compressor again, and a controller for controlling the overall operation of the air conditioner .

Meanwhile, the air conditioner is classified according to the type and number of the indoor unit, the outdoor unit, the control unit, and the connection unit. The RAC (Rotary Air Conditioner) composed of one indoor unit and the outdoor unit, one outdoor unit, a unit air conditioner consisting of at least one indoor unit and a duct, at least one outdoor unit, at least one indoor unit and a central air conditioner.

The air conditioner includes a separate type air conditioner in which an indoor unit and an outdoor unit are separated, an integrated type air conditioner in which an indoor unit and an outdoor unit are inserted as one unit, a wall-mounted type air conditioner and a frame type air conditioner configured to be mounted on the wall, A single type air conditioner configured to be used in a narrow place such as a home, and a capacity capable of driving one indoor unit.

A compressor for compressing a refrigerant includes a reciprocating compressor that compresses a refrigerant while linearly reciprocating the piston in the cylinder so that a compression space in which an operating gas is sucked or discharged is formed between a piston and a cylinder A rotary compressor for compressing the refrigerant while eccentrically rotating the roller along the inner wall of the cylinder so as to form a compression space in which a working gas is sucked or discharged between the cylinder and the eccentrically rotating roller; (Scroll Compressor) that compresses the refrigerant while the newborn scroll is rotated along the fixed scroll so that a compression space in which the working gas is sucked or discharged is formed between the orbiting scroll and the fixed scroll. do.

Generally, a motor (hereinafter referred to as a "motor") is used to drive a compressor of a refrigerator, and a TRIAC or an inverter is mainly used to drive the motor. In particular, a compressor control apparatus using an inverter controls a compressor by applying a pulse width modulation (PWM) signal to a compressor motor as a command value according to a load of a compressor. The compressor control apparatus provided with the disturbance observer estimates the load torque in real time and compensates the current command using the estimated load torque to reduce the ripple of the follower frequency of the compressor motor rotating at the fixed target frequency.

It is an object of the present invention to provide a compressor control apparatus for solving a time delay problem of a disturbance observer and an air conditioner including the same, in a system having a constant load pattern.

The embodiments of the present invention are directed to an apparatus for controlling a compressor using a load torque estimated by estimating a load torque using a disturbance observer and reducing a speed ripple caused by a time delay of a disturbance observer, There is another purpose in providing an air conditioner including the air conditioner.

Embodiments of the present invention have another object to provide a compressor control apparatus and an air conditioner including the same that compensate for the phase of the load torque estimated using the time delay according to the speed so that the load compensation is performed at an appropriate timing .

The compressor control apparatus according to an embodiment includes an inverter for converting a direct current voltage into a motor drive voltage in accordance with an inverter control signal and outputting the direct current voltage to a motor provided in the compressor, And a control unit. Here, the control unit includes a disturbance observer for estimating a load torque based on the motor drive current, and a delay compensator for compensating a phase of the estimated load torque and calculating a compensation current for the current command.

In the compressor control apparatus, the delay compensator includes: a storage unit for receiving and storing the estimated load torque from the disturbance observer; and a compensation unit for compensating a phase of the estimated load torque using a time delay value and an estimated phase according to the estimated speed And a compensation current calculation unit for calculating the compensation current based on the phase-compensated estimated load torque. The delay compensator may further comprise a machine phase calculating section for calculating the machine phase using the estimated phase. Here, the storage unit stores estimated torque information for each phase according to the mechanical phase.

An air conditioner according to an embodiment of the present invention includes an outdoor unit that compresses a refrigerant using a compressor, an indoor unit that is connected to the outdoor unit by a refrigerant pipe to perform air conditioning, and an indoor unit connected to the compressor, And a compressor control device for driving the motor. The compressor control apparatus includes a converter for converting an AC voltage of a commercial power source into a DC voltage, a DC link capacitor for smoothing and storing the DC voltage, and a DC link capacitor for converting the smoothed DC voltage into a motor drive voltage A current detecting unit for detecting a motor driving current input to the motor; a phase compensating unit for compensating a phase of the estimated load torque by estimating a load torque based on the motor driving current, And a control unit for calculating a compensation current for the current command based on the estimated load torque and generating the inverter control signal based on the current command and the compensation current.

Embodiments of the present invention solve the time delay problem of a disturbance observer by providing a delay compensator in a system having a constant load pattern.

The embodiments of the present invention reduce the speed ripple caused by the time delay of the disturbance observer by using a delay compensator in an apparatus for controlling a compressor using a load torque by estimating a load torque using a disturbance observer .

Embodiments of the present invention compensate for the phase of the load torque estimated using the time delay according to the speed, so that the load compensation is made at the proper timing, and the speed ripple is minimized.

Embodiments of the present invention are based on the fact that the time delay due to the bandwidth of the estimated load torque, the time delay due to the bandwidth of the disturbance observer itself, the time delay due to the current detection method, the time delay due to the sensorless control, So as to precisely control the compressor, thereby improving the stability of the system.

1 is a block diagram schematically illustrating the configuration of a compressor control apparatus according to an embodiment;
FIG. 2 is a block diagram showing a detailed configuration of the compressor control device of FIG. 1; FIG.
3 shows a mathematical model of a compressor motor and a disturbance observer;
4 is a graph showing the load torque estimated by the disturbance observer according to the phase;
5 is a graph showing a change in time delay according to a change in mechanical frequency;
6 shows frequency response curves of a disturbance observer and a low-pass filter;
7 is a block diagram illustrating a delay compensator in accordance with one embodiment;
8 is a diagram showing a phase change according to application of a delay compensator;
FIG. 9 is a perspective view showing an appearance of an air conditioner according to an embodiment; FIG. And
10 is a view showing a refrigerant cycle of the air conditioner of FIG.

9, an air conditioner according to an embodiment includes an outdoor unit 20 for compressing a refrigerant using a compressor, an indoor unit 10 connected to the outdoor unit 20 by a refrigerant pipe to perform air conditioning, And a compressor control device (not shown) connected to the compressor and driving a motor provided in the compressor according to an operation command. Here, the compressor control device may include a converter, a DC link capacitor, an inverter, a current detection unit, a control unit, and the like, as will be described later.

First, the refrigerant cycle of the air conditioner will be briefly described with reference to FIG.

10, the indoor unit 10 includes an indoor heat exchanger 11 for exchanging refrigerant and indoor air, an expansion valve (not shown) for expanding the refrigerant supplied from the outdoor unit, an indoor fan ).

10, the outdoor unit 20 includes a compressor 22 for compressing the refrigerant, an outdoor heat exchanger 21 for exchanging the refrigerant with the outdoor air, and an outdoor heat exchanger 21, A four-way valve 23 connected to be discharged to the indoor heat exchanger 11, an accumulator 24 for filtering refrigerant in a liquid state to supply gaseous refrigerant to the compressor, and an outdoor fan (not shown) . The compressor 22 may be divided into a constant speed compressor 22a and an inverter compressor 22b. The outdoor unit 20 may include an oil separator for separating oil from refrigerant flowing between the inverter compressor 22b and the four-way valve 23 and flowing.

The four-way valve 23 is connected to the outdoor heat exchanger 21 or the indoor heat exchanger 11 so that the refrigerant discharged from the constant-speed compressor 22a and the inverter compressor 22b is supplied to the outdoor heat exchanger 21 or the indoor heat exchanger 11 by switching the flow of the refrigerant. .

The accumulator 24 receives the refrigerant discharged from the four-way valve 23 and supplies only the gaseous refrigerant to the constant-speed compressor 22a or the inverter compressor 22b.

The constant-speed compressor 22a compresses and discharges a predetermined amount of refrigerant, and the inverter compressor 22b can regulate the amount of compression of the refrigerant within a predetermined range and discharge it. In particular, the constant-speed compressor 22a and the inverter compressor 22b can be driven by any one or both of them, and when either one of the constant-speed compressor 22a and the inverter compressor 22b is driven, In order to prevent the inflow of the refrigerant, check valves may be installed in the discharge side refrigerant pipes of the constant-speed compressor and the inverter compressor, respectively. The accumulator 24, the constant-speed compressor 22a, and the inverter compressor 22b are connected through a connector.

The oil separator includes an oil separator 22e provided between the check valve and the inverter compressor 22b and an oil separator 22b provided between the oil separator 22e and the inverter compressor 22b for separating the oil separated from the oil separator 22e. And a solenoid valve 22g. Here, the capillary tube 22f is provided on the oil separator side, and the solenoid valve is provided on the input side of the inverter compressor 22b. The solenoid valve is controlled by the control device and opened / closed at a predetermined cycle, so that oil separated from the oil separator 22e flows into the input side of the inverter compressor 22b. In general, the capacity of the constant speed compressor 22a is larger than the capacity of the inverter compressor 22b, and the inverter compressor 22b is initially driven based on the indoor load capacity during cooling and heating operation.

1, a compressor control apparatus according to an embodiment includes an inverter 300 for converting a DC voltage to a motor driving voltage according to an inverter control signal and outputting the same to a motor 400 provided in a compressor, And a control unit (500) for generating the inverter control signal based on the motor drive current. Here, it is preferable that the compressor is a compressor having a pattern in which the load variation during one mechanical rotation is constant, that is, a compressor having a constant load pattern.

The control unit 500 includes a disturbance observer 510 for estimating a load torque based on the motor driving current, a delay compensator 520 for compensating the phase of the estimated load torque and calculating a compensation current for the current command, .

Referring to FIG. 3, there is shown a mathematical model of the actual motor 400 and the disturbance observer 510 provided in the compressor according to the embodiments of the present invention. The relationship between the torque T _em (s) output by the motor 400 and the torque T _d (s) due to the actual load and the actual speed?

On the other hand, the relationship of the values estimated by the disturbance observer 510 is shown in Equation (2).

은 모터가 내는 토크의 추정 값이고,

는 추정 속도이다. 도 3에서,

는 추정 위상이다.here,

Is an estimated value of the torque exerted by the motor,

Is the estimated speed. 3,

Is the estimated phase.

이고,

이면, 추정하는 부하 토크(외란 토크)

가 된다. 이 값을 후술하는 전류 제어부에 보상해 주면 속도 리플을 줄일 수 있고, 진동을 감소시킬 수 있다. 도 4에 도시한 바와 같이, 압축기 상태(과부하, ARI, CHEER)에 따른 부하 토크는 위상에 따라 달라진다.If the disturbance observer 510 operates normally and there is no velocity error,

ego,

, The estimated load torque (disturbance torque)

. If this value is compensated by a current control section to be described later, the speed ripple can be reduced and the vibration can be reduced. As shown in Fig. 4, the load torque depending on the compressor state (overload, ARI, CHEER) varies depending on the phase.

For example, the disturbance observer 510 can be designed as shown in the following equation. A time delay may occur due to the bandwidth of the disturbance observer 510 itself, thereby limiting the speed ripple and further increasing the speed ripple. The control unit 500 includes a delay compensator 520 for this purpose.

,

,

,

는 각각 계수이다.here,

,

,

,

Respectively.

7, the delay compensator 520 includes a storage unit 521, a phase compensation unit 523, and a compensation current calculation unit 525. [ The storage unit 521 receives the estimated load torque estimated by the disturbance observer 510 and stores the estimated load torque. The phase compensator 523 compensates the phase of the estimated load torque using a time delay value and an estimated phase according to the estimated speed. Compensating current calculation unit 525 calculates the compensation current (i _{q _ com)} on the basis of the phase-compensated estimated load torque.

)을 이용하여 기계 위상(

)을 산출하는 기계 위상 산출부(527)를 더 포함할 수 있다. 이때, 상기 저장부(521)는, 상기 기계 위상에 따라 위상별로 추정 토크 정보를 저장한다.Further, the delay compensator 520 is configured to calculate the estimated phase

) And the machine phase (

And a machine phase calculating unit 527 for calculating a machine phase. At this time, the storage unit 521 stores estimated torque information for each phase according to the mechanical phase.

The storage unit 521 may store the time delay value for each speed in advance. The time delay value stored in the storage unit includes a time delay due to the bandwidth of the disturbance observer 510. [

) 및 추정 위상(

)을 산출하는 센서리스 제어부(530)를 더 포함할 수 있다. 상기 전류 검출 유닛(600)으로는 전류 트랜스듀서(Current Transducer)를 사용할 수 있으나, 비용 등의 이유로 하나의 션트 저항(Shunt Resistor)을 이용하여 상기 모터 구동 전류를 검출할 수 있다. 이 경우, 하나의 션트 저항으로 모터 구동 전류를 검출하고 이를 제어 유닛이 처리하는 데에 시간 지연이 발생하게 된다. 하나의 션트 저항을 이용한 모터 구동 전류의 검출에 따른 시간 지연도 상기 저장부(521)에 속도별 시간 지연 값에 포함될 수 있다. 즉, 상기 저장부(521)에 저장되는 시간 지연 값에는, 외란 관측기의 대역폭에 의한 시간 지연과 하나의 션트 저항에 의한 시간 지연이 포함될 수 있다.Referring to FIG. 2, the compressor control apparatus further includes a current detection unit 600 for detecting the motor drive current. Here, the control unit 500 may calculate the estimated speed (e.g.,

) And estimated phase (

And a sensorless controller 530 for calculating the sensorless controller 530. A current transducer may be used as the current detecting unit 600, but the motor driving current can be detected using one shunt resistor for reasons of cost and the like. In this case, a time delay occurs in detecting the motor drive current by one shunt resistor and processing it by the control unit. The time delay due to the detection of the motor drive current using one shunt resistor may also be included in the time dependent delay value in the storage unit 521. [ That is, the time delay value stored in the storage unit 521 may include a time delay due to a bandwidth of the disturbance observer and a time delay due to a single shunt resistor.

The delay compensator 520 may further include a filter unit (not shown) for low-pass filtering the estimated load torque inputted from the disturbance observer to a predetermined bandwidth. At this time, it is preferable that the filter unit is a low pass filter (LPF). For example, a low-pass filter can be designed as: < EMI ID = 1.0 >

The frequency response curves of the disturbance observer and the low-pass filter according to Equations (3) and (4) are shown in FIG.

The time delay value stored in the storage unit 521 may include a delay due to the bandwidth of the filter unit. The time delay value stored in the storage unit 521 may include a time delay in accordance with the estimation of the speed or phase in the sensorless controller 530. [ That is, the time delay value stored in the storage unit 521 may include a delay due to one shunt resistor, a delay due to the estimation of the sensorless controller, a delay due to the bandwidth of the disturbance observer itself, Or a delay due to < / RTI > As shown in FIG. 5, the storage unit 521 stores a time delay value for each machine frequency.

2, the control unit 500 includes a speed control unit 540 for generating the current command based on the speed command and the estimated speed, and a control unit 540 for generating a current command based on the current command and the compensation current, And a modulation control unit 560 for generating the inverter control signal based on the voltage command.

The compressor control device performs sensorless control of a motor provided in the compressor by using a mathematical model as shown in Fig. 2, and mainly uses the (d, q) coordinate system and controls the d-axis as a magnetic flux axis.

)과, 추정 속도(

)를 비교하는 비교기와, 속도 비례 적분 제어기(Proportional Integral Controller; PI)를 구비한다. 속도 제어부(540)는, 속도 지령과 추정 속도를 입력받아 비교하고, 속도 오차를 비례 적분하여 q축 전류 지령(i^* _q)을 생성하고, 이를 전류 제어부(550)에 출력한다.The speed control unit 540 controls the speed command

), Estimated speed (

), And a proportional integral controller (PI). The speed control unit 540 receives the speed command and the estimated speed, compares the speed command with the estimated speed, and generates the q-axis current command (i ^* _q ) by proportionally integrating the speed error and outputs it to the current controller 550.

The compressor control device can directly receive the torque command and the current command according to the magnetic flux command to control the motor, instead of receiving the speed command.

The current controller 550 receives the q-axis current command and the d-axis current command i ^* _d generated by the speed controller 540 and generates and outputs a voltage command. The current control unit 550 outputs the q-axis voltage command (V ^* _q ) to the pulse width modulation controller 560 via the current proportional integral controller and the filter through the q-axis current command. That is, the current controller 550 compares the q-axis current command and the q-axis detected current (i _q ) that is the axis-converted motor driving current detected through the current detecting unit. At this time, to compensate for the current control section 550 is a q-axis detected current (i _q) compensating current (i _{q_com)} passed through the disturbance observer 510 and a delay compensator 520 for. The current controller 550 outputs the q-axis voltage command (V ^* _q ) to the modulation controller 560 through the current proportional integral controller and the filter.

On the other hand, the current controller 550 outputs the d-axis voltage command V ^* _d to the modulation controller 560 via another current-proportional-plus-integral controller and filter. That is, the current controller 550 compares the d-axis detected current i _d , which is the axis-converted d-axis current command and the motor drive current, and outputs the difference therebetween, that is, the current error through the current proportional integral controller and the filter, And outputs a command (V ^* _d ) to the modulation control unit 560. Here, the voltages and currents are values on a synchronous coordinate system.

The modulation control unit 560 first converts the voltage command of the synchronous coordinate system into the voltage command of the stationary coordinate system (?,?). That is, the modulation control unit 560 converts (V ^* _d , V ^* _q ) into (V ^* _? , V ^* _? ). Further, the modulation control unit 560 converts the voltage command of the stationary coordinate system to the motor type to be driven and outputs it. That is, the modulation controller 55 is voltage command three-phase voltage command in the still coordinate system (S _a, S _b, S _c) with the pulse width modulation such as SVPWM (Space Vector Pulse Width Modulation); a (Pulse Width Modulation PWM) And outputs the converted signal to the inverter 300.

As described above, the compressor control apparatus and the air conditioner including the same according to the embodiments of the present invention solve the time delay problem of the disturbance observer by including the delay compensator in the system having the constant load pattern. The embodiments of the present invention reduce the speed ripple caused by the time delay of the disturbance observer by using a delay compensator in an apparatus for controlling a compressor using a load torque by estimating a load torque using a disturbance observer . Embodiments of the present invention compensate for the phase of the load torque estimated using the time delay according to the speed, so that the load compensation is made at the proper timing, and the speed ripple is minimized.

10: indoor unit 20: outdoor unit
100: converter 200: DC link capacitor
300: inverter 400: compressor motor
500: control unit 600: current detection unit
700: commercial power source 510: disturbance observer
520: delay compensator

Claims (14)

An inverter for converting a direct current voltage into a motor driving voltage according to an inverter control signal and outputting the direct current voltage to a motor provided in the compressor; And
And a control unit for generating the inverter control signal based on a speed command and a motor drive current,
Wherein the control unit comprises:
A disturbance observer for estimating a load torque based on the motor drive current; And
And a delay compensator for compensating the phase of the estimated load torque and calculating a compensation current for the current command,
Wherein the delay compensator comprises:
A storage unit for receiving and storing the estimated load torque from the disturbance observer;
A phase compensator for compensating a phase of the estimated load torque using a time delay value and an estimated phase according to an estimated speed; And
And a compensation current calculation unit for calculating the compensation current based on the phase-compensated estimated load torque. delete 2. The apparatus of claim 1, wherein the delay compensator comprises:
And a machine phase calculating unit for calculating a machine phase using the estimated phase,
Wherein,
And stores estimated torque information for each phase according to the mechanical phase. The apparatus according to claim 3,
And stores the time delay value for each speed in advance. The method according to any one of claims 3 and 4,
And a current detection unit for detecting the motor drive current,
Wherein the control unit comprises:
And a sensorless controller for calculating the estimated speed and the estimated phase based on the motor driving current. 6. The apparatus according to claim 5,
And the motor drive current is detected using one shunt resistor. 7. The apparatus of claim 6, wherein the delay compensator comprises:
And a filter unit that low-pass filters the estimated load torque inputted from the disturbance observer to a predetermined bandwidth. 8. The method of claim 7,
A delay due to one shunt resistor, a delay due to an estimation of the sensorless control unit, a delay due to the bandwidth of the disturbance observer itself, and a delay due to the bandwidth of the filter unit. 6. The apparatus according to claim 5,
A speed controller for generating the current command based on the speed command and the estimated speed;
A current controller for generating a voltage command based on the current command and the compensation current; And
And a modulation controller for generating the inverter control signal based on the voltage command. An outdoor unit compressing the refrigerant using a compressor;
An indoor unit connected to the outdoor unit through a refrigerant pipe to perform air conditioning; And
And a compressor control device connected to the compressor and driving a motor provided in the compressor in accordance with an operation command,
The compressor control device includes:
A converter for converting an AC voltage of a commercial power supply into a DC voltage;
A DC link capacitor for smoothing and storing the DC voltage;
An inverter for converting the smoothed direct current voltage into a motor drive voltage according to an inverter control signal and outputting the converted direct current voltage to the motor;
A current detection unit for detecting a motor drive current input to the motor; And
Estimating a load torque based on the motor drive current to compensate the phase of the estimated load torque, calculating a compensation current for the current command based on the phase-compensated estimated load torque, And a control unit for generating an inverter control signal,
Wherein the control unit comprises:
A disturbance observer for observing the estimated load torque based on the motor drive current; And
And a delay compensator for compensating a phase of the estimated load torque and calculating the compensation current,
Wherein the delay compensator comprises:
A storage unit for receiving and storing the estimated load torque from the disturbance observer;
A phase compensator for compensating a phase of the estimated load torque using a time delay value and an estimated phase according to an estimated speed; And
And a compensation current calculation unit for calculating the compensation current based on the phase-compensated estimated load torque. delete 11. The apparatus according to claim 10,
A sensorless controller for calculating an estimated speed and an estimated phase based on the motor driving current;
A speed controller for generating the current command based on a speed command and the estimated speed;
A current controller for generating a voltage command based on the current command and the compensation current; And
And a modulation controller for generating the inverter control signal based on the voltage command. 13. The apparatus of claim 12, wherein the delay compensator comprises:
And a machine phase calculating unit for calculating a machine phase using the estimated phase. 14. The apparatus of claim 13,
And stores the time delay value for each speed in advance.

Images