KR20210092540A - Power transforming apparatus and air conditioner using the same - Google Patents

Abstract

The present invention relates to a power converting device capable of reducing noise and vibration of a compressor motor even when driven at a low speed and air conditioner using the same. According to the present invention, the power converting device comprises: an inverter unit that outputs a current for driving a compressor motor; and an inverter control unit for controlling the inverter unit. The inverter control unit senses a current outputted from the inverter unit, calculates a calculation speed of the compressor motor based on the sensed current, applies a low-pass filter in relation to the calculation speed if the calculation speed belongs to a low speed range, and generates a target current by performing time delay compensation.

Description

POWER TRANSFORMING APPARATUS AND AIR CONDITIONER USING THE SAME

The present invention relates to a power conversion device, and more particularly, to a power conversion device capable of reducing noise and vibration of a compressor motor even when driven at a low speed, and an air conditioner including the same.

The air conditioner is installed to provide a more comfortable indoor environment for humans by discharging hot and cold air into the room to create a comfortable indoor environment, controlling the indoor temperature, and purifying the indoor air. In general, an air conditioner includes an indoor unit configured as a heat exchanger and installed indoors, and an outdoor unit configured as a compressor and a heat exchanger and supplying refrigerant to the indoor unit.

In general, a compressor of an air conditioner uses a motor as a driving source. These motors are supplied with AC power from a power conversion device.

It is generally known that such a power converter mainly comprises a rectifier, a power factor controller, and an inverter type power converter. The AC commercial voltage output from the commercial power supply is rectified by the rectifying unit. The voltage rectified by the rectifier is supplied to a power converter such as an inverter. In this case, the power converter generates AC power for driving the motor by using the voltage output from the rectifier.

In some cases, a DC-DC converter for improving the power factor may be provided between the rectifier and the inverter, and a DC stage capacitor may be provided between the converter and the inverter.

In the control of such a compressor motor, it is necessary to sense the position of the rotor.

In general, a sensorless method of detecting a position of a rotor using a counter electromotive force induced in an inverter by rotation of a rotor is commonly used because it does not require a sensor.

On the other hand, in such a compressor, noise and vibration problems at low speed are pointed out as issues.

In particular, in the case of a sensorless motor, when the motor is operated at a low speed, it is difficult to accurately determine the position of the rotor because back electromotive force is not sufficiently generated.

In addition, when the wrong disturbance compensation is performed in a state where the position of the rotor is not correct, a problem of increasing vibration is caused.

Accordingly, there is a demand for a power conversion device having an inverter controller that reduces noise and vibration even when the sensorless motor operates at a low speed and is not affected by the characteristics of the compressor.

Korean Patent Registration No. 10-1162954

SUMMARY OF THE INVENTION The present invention aims to solve the above and other problems.

An object of the present invention is to control the speed of the compressor motor by performing proportional-integral control and ripple removal on the sensed speed during sensorless low-speed operation of the compressor motor, thereby minimizing noise and vibration of the compressor motor. and an air conditioner including the same.

Another object of the present invention is to remove ripple through a low-pass filter when the sensorless compressor motor operates at a low speed, and perform time delay compensation therefor, so that power capable of effectively compensating for disturbance even in the low-speed operation of the compressor motor An object of the present invention is to provide a conversion device and an air conditioner including the same.

In addition, an object of the present invention is a power conversion device capable of effectively controlling in all speed ranges of the compressor motor by distinguishing between a case in which the operating speed of the compressor motor is low speed and a case in which it is not, and performing disturbance compensation only when the operating speed is low speed, and the same. It is intended to provide an air conditioner that includes

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned may be understood by the following description, and will be more clearly understood by the examples of the present invention. Moreover, it will be readily apparent that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

The power conversion device according to the present invention may include an inverter unit that outputs a current for driving a compressor motor and an inverter control unit that controls the inverter unit. The inverter control unit senses the current output from the inverter unit, calculates the operation speed of the compressor motor based on the sensed current, and applies a low-pass filter in association with the operation speed if the operation speed falls within a low speed range and time delay compensation is performed to generate a target current.

In an embodiment, the inverter control unit reflects a first delay time caused by the low-pass filter and a second delay time due to a difference between a time point at which the current is sensed and a time point at which the calculation speed is calculated and applied. The delay compensation may be performed.

In an embodiment, the inverter control unit may not apply the low-pass filter when the calculation speed falls within a normal range rather than the low speed range.

In an embodiment, the inverter control unit may perform time delay compensation based on a delay time due to a difference between a time point of sensing the current and a time point of calculating and applying the calculation speed.

In an embodiment, the inverter control unit includes a current sensing unit for sensing the current output from the inverter unit, a speed calculation unit for calculating the calculation speed based on the current sensed by the current sensing unit, and the calculation speed and the target speed. It may include a speed control unit for generating the target current based on the target current. When the calculation speed falls within the low speed range, the speed controller may generate a target current by applying a low-pass filter in association with the calculation speed and performing time delay compensation.

In an embodiment, the speed control unit includes a subtractor that calculates and outputs a difference between the calculation speed and the target speed, a proportional-integral controller that performs proportional-integration control based on the difference between the calculation speed and the target speed; A low-pass filter that receives the output of the subtractor and removes a ripple component with respect to the sensed current, a delay compensation filter that receives the output of the low-pass filter and compensates for the delay, and an output of the delay compensation filter and an adder configured to add the output of the resonance controller and the output of the proportional-integral controller and the output of the resonance controller to output the target current.

In an embodiment, the speed control unit includes a subtractor that calculates and outputs a difference between the calculation speed and the target speed, a proportional-integral controller that performs proportional-integration control based on the difference between the calculation speed and the target speed; A switch connected to the output terminal of the subtractor and configured to provide an output of the subtractor to either a first path or a second path according to the operation speed, provided on the first path, to the first path by the switch A low-pass filter that receives the provided output of the subtractor and removes a ripple component with respect to the sensed current, is provided on the first path, receives the output of the low-pass filter, and compensates for the delay an output of a soft compensation filter, a resonance controller that performs resonance control by receiving an output of the delay compensation filter, or an output of the subtractor provided to the second path by the switch, and an output of the proportional-integral controller and the and an adder configured to add the output of the resonance controller to output the target current.

In an embodiment, the switch may provide the output of the subtractor to the first path when the operation speed falls within the low speed range.

In an embodiment, the speed control unit includes a subtractor that calculates and outputs a difference between the calculation speed and the target speed, a proportional-integral controller that performs proportional-integration control based on the difference between the calculation speed and the target speed; A switch connected to the output terminal of the subtractor and configured to provide an output of the subtractor to either a first path or a second path according to the operation speed, provided on the first path, to the first path by the switch A low-pass filter that receives the provided output of the subtractor and removes a ripple component with respect to the sensed current, which is provided on the first path, receives the output of the low-pass filter, and is generated by the low-pass filter A first delay compensation filter for compensating for the delay, a second delay compensation filter for compensating for a delay time due to a difference between the time of sensing the current and the time of calculating and applying the operation speed, the second delay compensation and a resonance controller that receives the output of the filter and performs resonance control, and an adder that adds the output of the proportional-integral controller and the output of the resonance controller to output the target current.

In an embodiment, the second delay compensation filter may receive an output of the first delay compensation filter or an output of the subtractor provided to the second path by the switch.

In an embodiment, the switch may provide the output of the subtractor to the first path when the operation speed falls within the low speed range.

The air conditioner according to the present invention is an air conditioner using a compressor, and may include a compressor motor for driving the compressor and a power conversion device for supplying AC power to the compressor motor. The power conversion device may include an inverter unit that outputs a current for driving the compressor motor and an inverter control unit that controls the inverter unit. The inverter control unit senses the current output from the inverter unit, calculates the operation speed of the compressor motor based on the sensed current, and applies a low-pass filter in association with the operation speed if the operation speed falls within a low speed range and time delay compensation is performed to generate a target current.

The power conversion device and the air conditioner including the same according to the present invention control the speed of the compressor motor by performing proportional-integral control and ripple removal on the sensed speed during sensorless low-speed operation of the compressor motor, thereby reducing the noise of the compressor motor and It has the effect of minimizing vibration.

The power conversion device and the air conditioner including the same according to the present invention remove ripple through a low-pass filter when the sensorless compressor motor operates at a low speed, and compensate for the time delay, so that it is effective even in the low speed operation of the compressor motor. It has the effect of performing disturbance compensation.

The power conversion device and the air conditioner including the same according to the present invention are effectively controlled in all speed ranges of the compressor motor by distinguishing between a case in which the running speed of the compressor motor is low and not, and performing disturbance compensation only when the operating speed is low. There is an effect that can be done.

In addition to the above-described effects, the specific effects of the present invention will be described together while describing specific details for carrying out the invention below.

1 is a block diagram illustrating a power conversion device according to an embodiment of the present invention.
2 is a circuit diagram illustrating a power conversion device according to an embodiment of the present invention.
3 is a block diagram illustrating an inverter control unit of a power conversion device according to an embodiment of the present invention.
4 is a block diagram illustrating an example of a speed control unit of an inverter control unit according to an embodiment of the present invention.
5 is a block diagram illustrating another example of the speed control unit of the inverter control unit according to an embodiment of the present invention.
FIG. 6 is a block diagram illustrating a case in which the speed control unit illustrated in FIG. 5 operates in a low speed range, and FIG. 7 is a block diagram illustrating a case in which the speed control unit illustrated in FIG. 5 operates in a normal range.
8 is a block diagram illustrating another example of the speed control unit of the inverter control unit according to an embodiment of the present invention.
9 is a block diagram illustrating a case in which the speed control unit illustrated in FIG. 8 operates in a low speed range, and FIG. 10 is a block diagram illustrating a case in which the speed control unit illustrated in FIG. 8 operates in a normal range.

The above-described objects, features and advantages will be described below in detail with reference to the accompanying drawings, and accordingly, those of ordinary skill in the art to which the present invention pertains will be able to easily implement the technical idea of the present invention. In describing the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

Although the first, second, etc. are used to describe various elements, these elements are not limited by these terms, of course. These terms are only used to distinguish one component from other components, and unless otherwise stated, the first component may be the second component, of course.

Also, when it is described that a component is "connected", "coupled" or "connected" to another component, the components may be directly connected or connected to each other, but other components are "interposed" between each component. It is to be understood that “or, each component may be “connected,” “coupled,” or “connected” through another component.

Also, as used herein, the singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "consisting of" or "comprising" should not be construed as necessarily including all of the various components or various steps described in the specification, some of which components or some steps are It should be construed that it may not include, or may further include additional components or steps.

Hereinafter, a power conversion device and an air conditioner including the same according to some embodiments of the present invention will be described.

1 is a block diagram illustrating a power conversion apparatus according to the present invention, and FIG. 2 is a circuit diagram illustrating a power conversion apparatus according to the present invention.

1 and 2, the power conversion device 100 is a rectifying unit 110 for rectifying the AC power supply 10, and a converter unit for stepping up/down the DC voltage rectified by the rectifying unit 110 or controlling the power factor ( 120), the converter control unit 130 for controlling the converter unit 120, the inverter unit 140 for outputting a three-phase alternating current, the inverter control unit 150 for controlling the inverter unit 140, and the converter unit 120 and a DC terminal capacitor C between the inverter unit 140 and the inverter unit 140 .

The inverter unit 140 outputs a three-phase alternating current, and this output current is supplied to the motor 200 . Here, the motor 200 may be a compressor motor driving the air conditioner.

Hereinafter, it will be described as an example that the motor 200 is a compressor motor driving the air conditioner, and the power conversion device 100 is a motor driving device that drives the compressor motor. However, the motor 290 is not limited to the compressor motor, and may be used in various application products using a frequency-variable AC voltage, for example, AC motors such as refrigerators, washing machines, electric vehicles, automobiles, and vacuum cleaners.

The power conversion apparatus 100 may further include a DC terminal voltage detector (B), an input voltage detector (A), an input current detector (D), and an output current detector (E) to drive the compressor motor.

The power conversion device 100 receives AC power from the system, converts the power, and supplies the converted power to the motor 200 .

The converter unit 120 converts the input AC power supply 10 into a DC power supply. The converter unit 120 may use a DC-DC converter that operates as a power factor control unit (PFC). In addition, the DC-DC converter may use a boost converter. In some cases, the converter 120 may be a concept including the rectifying unit 110 . Hereinafter, the converter unit 120 will be described as an example using a step-up converter.

The rectifying unit 110 receives and rectifies the single-phase AC power supply 10 , and outputs the rectified power to the converter unit 120 side. For example, the rectifier 110 may use a full-wave rectification circuit using a bridge diode.

The converter unit 120 may perform a power factor improvement operation while boosting and smoothing the voltage rectified by the rectifying unit 110 .

The converter unit 120 includes an inductor L1 connected to the rectifying unit 110, a switching element Q1 connected to the inductor L1, a capacitor C connected in parallel with the switching element Q1, and a switching A diode D1 connected between the device Q1 and the capacitor C may be included.

The converter unit 120 is a step-up converter capable of obtaining an output voltage higher than the input voltage. When the switching element Q1 is turned on, the diode D1 is cut off and energy is stored in the inductor L1, and energy is stored in the capacitor C. As the stored charge is discharged, an output voltage is generated at the output terminal.

When the switching element Q1 is cut off, the energy stored in the inductor L1 is added when the switching element Q1 is turned on and transferred to the output terminal.

For example, the switching element Q1 may perform a switching operation according to a separate pulse width modulation (PWM) signal. That is, the PWM signal transmitted from the converter control unit 130 may be applied to a base (or gate) terminal of the switching element Q1 to drive the switching operation of the switching element Q1 by this PWM signal. .

The switching element Q1 may use a power transistor, for example, an insulated gate bipolar mode transistor (IGBT). The IGBT is a switching device having a structure of a power MOSFET (metal oxide semi-conductor field effect transistor) and a bipolar transistor, and is a device capable of low driving power, high-speed switching, high withstand voltage, and high current density.

In this way, the converter control unit 130 may control the turn-on timing of the switching element Q1 in the converter unit 120 . Accordingly, the converter control signal Sc for the turn-on timing of the switching element Q1 may be output.

To this end, the converter control unit 130 may receive the input voltage Vs and the input current Is from the input voltage detection unit A and the input current detection unit B, respectively.

The output voltage passing through the rectifying unit 110 may be charged in the DC stage capacitor C or drive the inverter unit 140 .

The input voltage detector A may detect the input voltage Vs from the input AC power supply 10 . For example, it may be located in front of the rectifying unit 110 .

The input voltage detection unit A may include a resistance element, an OP AMP, and the like for voltage detection. For example, the detected input voltage Vs is a discrete signal in the form of a pulse and may be applied to the converter control unit 130 to generate the converter control signal Sc.

The input current detector D may detect the input current Is from the input AC power supply 10 . The input current detecting unit D may be located in front of the rectifying unit 110 .

The input current detection unit D may include a current sensor, a current transformer (CT), a shunt resistor, and the like for current detection. The detected input voltage Is is a discrete signal in the form of a pulse, and may be applied to the converter control unit 130 to generate the converter control signal Sc.

The DC voltage detector B detects the pulsating voltage Vdc of the DC stage capacitor C. For this power detection, a resistive element, an OP AMP, etc. may be used. The detected voltage (Vdc) of the DC terminal capacitor (C) 160 may be applied to the inverter control unit 150 as a discrete signal in the form of a pulse, and the DC voltage of the DC terminal capacitor (C) ( Vdc), the inverter control signal Si may be generated.

Meanwhile, unlike the illustrated example, the detected DC voltage may be applied to the converter control unit 130 and used to generate the converter control signal Sc.

The inverter unit 140 includes a plurality of inverter switching elements Qa, Qb, Qc, Qa', Qb', Qc', and provides a predetermined DC power supply (Vdc) smoothed by the on/off operation of the switching elements. The frequency may be converted into three-phase AC power and output to the three-phase motor 200 .

Specifically, the inverter unit 140 has a pair of upper switching elements Qa, Qb, Qc and lower switching elements Qa', Qb', Qc' connected in series to each other, and a total of three pairs of upper and lower sides The switching elements may be connected in parallel to each other.

Like the converter unit 120 , the switching elements Qa, Qb, Qc, Qa', Qb', and Qc' of the inverter unit may use a power transistor, for example, an insulated gate bipolar transistor (insulated gate bipolar mode). transistor (IGBT) can be used.

The inverter control unit 150 may output an inverter control signal Si to the inverter unit 140 in order to control the switching operation of the inverter unit 140 . The inverter control signal (Si) is a switching control signal of the pulse width modulation method (PWM), and is applied to the output current (io) flowing through the motor 200 and the DC terminal voltage (Vdc) at both ends of the DC terminal capacitor (C) 160 . It can be generated and outputted based on it.

At this time, the output current io may be detected from the output current detection unit E, and the DC terminal voltage Vdc may be detected from the DC terminal voltage detection unit B.

The output current detection unit E may detect the output current io flowing between the inverter unit 140 and the motor 200 . That is, the current flowing through the motor 200 is detected. The output current detection unit E may detect all of the output currents ia, ib, and ic of each phase, or may detect the output currents of two phases using three-phase balance.

The output current detection unit E may be positioned between the inverter unit 140 and the motor unit 200 , and a current transformer (CT), a shunt resistor, or the like may be used to detect the current.

The inverter control unit 150 may sense the current output from the inverter unit 140 , and calculate the speed of the compressor motor 200 based on the sensed current. As described above, the speed of the compressor motor 200 calculated from the output current of the inverter unit 140 will be referred to as a calculated speed below.

The inverter control unit 150 generates a target current for driving control of the compressor motor 200 based on the operation speed and the target speed of the compressor motor 200 and generates a driving signal based on this to drive the inverter unit 140 . can

When the calculated speed of the compressor motor 200 falls within the low speed range, the inverter control unit 150 may apply a low-pass filter in relation to the calculated speed and also perform time delay compensation.

This is because, when the speed of the compressor motor 200 is in the low speed range, the current output from the inverter unit 140 is relatively small and the influence of the ripple increases, so the speed of the compressor motor 200 may be calculated inaccurately. because there is Accordingly, the inverter control unit 150 may reduce ripple by applying the low-pass filter in relation to the operation speed, and may perform delay compensation in order to compensate for the delay induced by the low-pass filter.

Here, the low speed range may be preset and determined, for example, may be a range including a speed of 10 Hz or less. In addition, outside the low speed range may be set as a normal range, for example, may be a range including a speed greater than 10 Hz.

The inverter control unit 150 may perform a low-pass filter and time delay compensation therefor when the speed of the compressor motor 200 is in a low speed range.

When the speed of the compressor motor 200 is in the normal range, the inverter control unit 150 may not perform the ripple compensation, that is, the low-pass filter and the time delay compensation therefor. That is, since the inverter control unit 150 does not apply the low-pass filter, the time delay compensation by the low-pass filter is not performed. On the other hand, even in such a case, the inverter control unit 150 compensates for the time difference of applying the calculation speed from the inverter current, that is, only the delay time due to the difference between the time of sensing the inverter current and the time of calculating and applying the calculation speed. Delay compensation can be performed by reflecting it.

For example, the inverter control unit 150 may calculate the difference between the calculation speed and the target speed and perform inverter control based thereon. In this case, a low-pass filter is applied to the difference between the calculation speed and the target speed to reduce ripple. A delay compensation filter may be applied to compensate and compensate for the delay caused by the low-pass filter.

The speed controller of the inverter controller 150 may include a proportional-integral controller (PI controller) and a resonance controller. Here, the proportional-integral controller performs proportional-integral control based on the difference between the calculation speed and the target speed, and the resonance controller is connected in parallel with the proportional-integral controller and has a low-pass filter and a delay compensation filter at the front end of the resonance controller. can be applied to remove the ripple component.

Here, the delay compensation filter may be a first order all-pass filter, but is not limited thereto.

In addition, the low-pass filter and the delay compensation filter may be connected in parallel with the proportional-integral controller and connected in series with the resonance controller.

Therefore, in the present invention, based on the speed sensed from the compressor motor, when the compressor motor is in the low speed range, a low-pass filter for removing ripple and time delay compensation are performed to control the speed of the compressor motor to reduce the speed of the compressor. It is possible to minimize noise and vibration based on accurate control even for the operating compressor motor.

Various embodiments of the inverter control unit 150 will be described in more detail below with reference to FIGS. 3 to 10 .

3 is a block diagram for explaining the inverter control unit of the power conversion device according to the present invention.

As shown in FIG. 3 , the inverter control unit according to an embodiment of the present invention includes a current sensing unit 151 , a speed calculating unit 152 , a speed control unit 153 , a torque control unit 154 , and a current control unit 155 . and a driving unit 156 .

The current sensing unit 151 may sense a current output from the inverter unit 140 . For example, the current sensing unit 151 may sense the three-phase output currents ia, ib, and ic from the inverter unit 140 .

When the current sensing unit 151 receives the estimated position signal Θe from the speed calculating unit 152, the d-axis estimated current id and the q-axis estimated current iq are sensed according to the received estimated position signal Θe. It may output to the torque control unit 154 .

The speed calculating unit 152 may calculate the speed of the compressor motor 200 based on the sensed current. Here, the speed calculator 152 may be a sensorless controller, but is not limited thereto.

For example, the sensorless controller may detect the speed of the compressor motor 200 based on sensed current information. In addition, the speed calculating unit 152 may estimate the rotor position of the compressor motor 200 based on the sensed current and output the estimated position signal Θe to the current sensing unit 151 .

The speed controller 153 may generate the target current I* by performing proportional-integral control and ripple removal based on the calculated operation speed W^r and the target speed W*r.

When the calculation speed falls within the low speed range, the speed controller 153 may generate the target current I* by applying a low-pass filter in association with the calculation speed and performing time delay compensation.

The speed controller 153 may include a proportional-integral controller (PI controller), a resonance controller, a low-pass filter, and a delay compensation filter. Here, the delay compensation filter can compensate the time delay caused by the low-pass filtering for the operation speed (W^r) and the target speed (W*r) and output it to the resonance controller, thereby without a time error A target reward value can be output.

In an embodiment, the delay compensation filter may compensate for both the first delay time caused by the low-pass filter and the second delay time caused by the difference between the time of sensing the current and the time of applying the calculation speed.

For example, the delay compensation filter includes a first delay compensation filter for compensating for a first delay time caused by the low-pass filter, and a second delay time due to a difference between a time of sensing a current and a time of applying an operation speed. A first delay compensation filter for compensating may be included.

The delay compensation filter may be at least one first order all-pass filter, but is not limited thereto.

The torque controller 154 generates a d-axis target current (i*d) and a q-axis target current (i*q) based on the generated target current I* and the current sensed by the current sensing unit 151 . can do.

In addition, the current controller 155 may generate the target voltages v*d and v*q based on the d-axis target current i*d and the q-axis target current i*q.

The driving unit 156 generates the driving signals Sa, Sb, Sc based on the generated target voltage target voltages v*d, v*q, and the inverter unit according to the generated driving signals Sa, Sb, Sc. 140 can be driven.

For example, the generated driving signals Sa, Sb, and Sc may be PWM signals having a predetermined duty.

The inverter unit 140 may drive the compressor motor 200 by outputting a three-phase AC current according to the driving signals Sa, Sb, and Sc.

4 is a block diagram illustrating an example of a speed control unit of an inverter control unit according to an embodiment of the present invention.

Referring to FIG. 4 , the speed controller according to an embodiment of the present invention includes a subtractor 401 , a proportional-integral (PI) controller 421 , a low-pass filter 431 , a delay compensation filter 432 , and a resonance controller. 433 and an adder 441 .

The subtractor 401 calculates and outputs the difference between the calculation speed W^r and the target speed W*r.

The proportional-integration controller 421 performs proportional-integration control based on the difference between the calculation speed W^r and the target speed W*r.

The low-pass filter 431 , the delay compensation filter 432 , and the resonance controller 433 are connected in series, and they may be connected in parallel with the proportional-integral controller 421 .

The low-pass filter 431 receives the output of the subtractor 401 as an input. The low-pass filter 431 performs a filtering function to remove a ripple component with respect to the sensed current. This is because, when the compressor motor operates at a low speed, the sensed current amount is also reduced, and accordingly, a small current ripple has a relatively large effect when the sensed current amount is small.

The delay compensation filter 432 receives the output of the low-pass filter 431 . When filtering is performed by the low-pass filter 431 , a time delay is generated accordingly, so the time delay compensation filter 432 performs time delay compensation.

In an embodiment, the delay compensation filter 432 may compensate for the delay caused by the low-pass filter 431 .

In another embodiment, the delay compensation filter 432 compensates not only for the delay caused by the low-pass filter, but also for the delay caused by the difference between the time of sensing the current and the time of calculating and applying the calculation speed. can

The resonance controller 433 receives the output of the delay compensation filter 432 and performs resonance control.

The adder 441 adds the output of the proportional-integral controller 421 and the output of the resonance controller 433 to output the target current I*.

5 is a block diagram illustrating another example of the speed control unit of the inverter control unit according to an embodiment of the present invention. 6 is a block diagram illustrating a case in which the speed control unit illustrated in FIG. 5 operates in a low speed range, and FIG. 7 is a block diagram illustrating a case in which the speed control unit illustrated in FIG. 5 operates in a normal range.

5 to 7 , the speed control unit according to an embodiment of the present invention includes a subtractor 501 , a switch 511 , a proportional-integral controller 521 , a low-pass filter 531 , and a delay compensation filter. 532 , a resonance controller 533 and an adder 541 .

The subtractor 501 calculates and outputs the difference between the calculation speed W^r and the target speed W*r.

The proportional-integration controller 521 performs proportional-integration control based on the difference between the calculation speed W^r and the target speed W*r.

The switch 511 is connected to the output terminal of the subtractor 501 . The switch 511 provides the output of the subtractor 501 to either the first path or the second path according to the operation speed.

Here, as shown in FIG. 6 , the first path is a path through which the output of the subtractor 501 is input to the resonance controller 533 through the low-pass filter 531 and the delay compensation filter 532 . The second path is a path through which the output of the subtractor 501 is directly input to the resonance controller 533 as shown in FIG. 7 .

When the operation speed is in the low speed range, the switch 511 may provide the output of the subtractor 501 to the first path to remove ripple and perform time delay compensation.

In addition, the switch 511 may provide the output of the subtractor 501 to the second path when the operation speed is within the normal range, so that filtering for ripple removal is not performed. This is because, when the compressor motor rotates at a sufficient speed, the amount of current sensed is also significant, and in this case, there may be little effect of a small current ripple.

The low-pass filter 431 receives the output of the subtractor 401 provided to the first path by the switch 511 . The description of the low-pass filter 431 replaces the above-mentioned bar with reference to FIG. 4 .

The delay compensation filter 432 receives the output of the low-pass filter 431 . When filtering is performed by the low-pass filter 431 , a delay is generated accordingly, so the delay compensation filter 432 performs such delay compensation.

In an embodiment, the delay compensation filter 432 may compensate for the delay caused by the low-pass filter 431 .

In another embodiment, the delay compensation filter 432 compensates not only for the delay caused by the low-pass filter, but also for the delay caused by the difference between the time of sensing the current and the time of calculating and applying the calculation speed. can

The resonance controller 433 performs resonance control by receiving the output of the delay compensation filter 432 or the output of the subtractor 501 provided to the second path by the switch 511 .

The adder 441 adds the output of the proportional-integral controller 421 and the output of the resonance controller 433 to output the target current I*.

8 is a block diagram illustrating another example of the speed control unit of the inverter control unit according to an embodiment of the present invention. 9 is a block diagram illustrating a case in which the speed control unit illustrated in FIG. 8 operates in a low speed range, and FIG. 10 is a block diagram illustrating a case in which the speed control unit illustrated in FIG. 8 operates in a normal range.

8 to 10 , the speed controller according to an embodiment of the present invention includes a subtractor 801 , a switch 811 , a proportional-integral controller 821 , a low-pass filter 831 , and a first delay delay. It may include a compensation filter 832 , a second delay compensation filter 833 , a resonance controller 834 , and an adder 841 .

The subtractor 801 calculates and outputs the difference between the calculation speed W^r and the target speed W*r.

The proportional-integration controller 821 performs proportional-integration control based on the difference between the calculation speed W^r and the target speed W*r.

The switch 811 is connected to the output terminal of the subtractor 801 . The switch 811 provides the output of the subtractor 801 to either the first path or the second path according to the operation speed.

Here, in the first path, as shown in FIG. 9 , the output of the subtractor 801 passes through the low-pass filter 831 and the first delay compensation filter 832 to the second delay compensation filter 833 . This is the input path. The second path is a path through which the output of the subtractor 801 is input to the second delay compensation filter 833 as shown in FIG. 7 .

The switch 511 provides the output of the subtractor 501 to the second path when the operation speed is within the normal range, so that filtering for removing ripple is not performed. This is because, when the compressor motor rotates at a sufficient speed, the amount of current sensed is also significant, and in this case, there may be little effect of a small current ripple.

The low-pass filter 431 receives the output of the subtractor 401 provided to the first path by the switch 511 . The description of the low-pass filter 431 replaces the above-mentioned bar with reference to FIG. 4 .

The first delay compensation filter 832 may receive the output of the low-pass filter 831 and compensate for the delay caused by the low-pass filter 431 .

The second delay compensation filter 833 may receive the output of the first delay compensation filter 832 through the first path, or may receive the output of the subtractor 801 through the second path.

The second delay compensation filter 833 may compensate for a delay caused by a difference between a time of sensing a current and a time of calculating and applying a calculation speed.

When the operation speed is in the low speed range, the switch 811 may provide the output of the subtractor 801 to the first path to remove the ripple and compensate for the time delay.

The resonance controller 433 performs resonance control by receiving the output of the delay compensation filter 432 or the output of the subtractor 501 provided to the second path by the switch 511 .

The adder 441 adds the output of the proportional-integral controller 421 and the output of the resonance controller 433 to output the target current I*.

As described above, the present invention has been described with reference to the illustrated drawings, but the present invention is not limited by the embodiments and drawings disclosed in this specification, and various methods can be obtained by those skilled in the art within the scope of the technical spirit of the present invention. It is obvious that variations can be made. In addition, although the effects according to the configuration of the present invention are not explicitly described and described while describing the embodiments of the present invention, it is natural that the effects predictable by the configuration should also be recognized.

100: power conversion device 110: rectifying unit
110: converter unit 130: converter control unit
140: inverter unit 150: inverter control unit
151: current sensing unit 152: speed calculating unit
153: speed control 154: torque control
155: current control unit 156: driving unit
200: motor

Claims (12)

an inverter unit outputting a current for driving the compressor motor; and
an inverter control unit for controlling the inverter unit;
including,
The inverter control unit,
Senses the current output from the inverter unit and calculates the operation speed of the compressor motor based on the sensed current. If the operation speed falls within the low speed range, a low-pass filter is applied in relation to the operation speed and delay compensation is performed. A power conversion device that generates a target current by performing
According to claim 1, wherein the inverter control unit
A power conversion device for performing the delay compensation by reflecting a first delay time caused by the low-pass filter and a second delay time caused by a difference between a time of sensing the current and a time of calculating and applying the operation speed .
According to claim 1, wherein the inverter control unit
When the operation speed falls within the general range rather than the low speed range, the power conversion device does not apply a low-pass filter.
The method of claim 3, wherein the inverter control unit
A power conversion device for performing time delay compensation by a delay time due to a difference between a time point of sensing the current and a time point of calculating and applying the calculation speed.
According to claim 1, wherein the inverter control unit
a current sensing unit sensing the current output from the inverter unit;
a speed calculation unit for calculating the calculation speed based on the current sensed by the current sensing unit; and
a speed controller configured to generate the target current based on the calculation speed and the target speed;
including,
The speed control
When the calculation speed falls within the low speed range, a low-pass filter is applied in association with the calculation speed and time delay compensation is performed to generate a target current.
The method of claim 5, wherein the speed control unit
a subtractor calculating and outputting a difference between the calculation speed and the target speed;
a proportional-integral controller that performs proportional-integral control based on a difference between the calculation speed and the target speed;
a low-pass filter receiving the output of the subtractor and removing a ripple component with respect to the sensed current;
a delay compensation filter receiving the output of the low-pass filter and compensating for the delay;
a resonance controller receiving the output of the delay compensation filter and performing resonance control; and
an adder for outputting the target current by adding the output of the proportional-integral controller and the output of the resonance controller;
A power conversion device comprising a.
The method of claim 5, wherein the speed control unit
a subtractor calculating and outputting a difference between the calculation speed and the target speed;
a proportional-integral controller that performs proportional-integral control based on a difference between the calculation speed and the target speed;
a switch connected to an output terminal of the subtractor and configured to provide an output of the subtractor to either a first path or a second path according to the operation speed;
a low-pass filter provided on the first path, receiving an output of the subtractor provided to the first path by the switch, and removing a ripple component with respect to the sensed current;
a delay compensation filter provided on the first path, receiving the output of the low-pass filter, and compensating for the delay;
a resonance controller configured to receive an output of the delay compensation filter or an output of the subtractor provided to the second path by the switch to perform resonance control; and
an adder for outputting the target current by adding the output of the proportional-integral controller and the output of the resonance controller;
A power conversion device comprising a.
8. The method of claim 7, wherein the switch is
When the operation speed falls within the low speed range, the power converter provides the output of the subtractor to the first path.
The method of claim 5, wherein the speed control unit
a subtractor calculating and outputting a difference between the calculation speed and the target speed;
a proportional-integral controller that performs proportional-integral control based on a difference between the calculation speed and the target speed;
a switch connected to an output terminal of the subtractor and configured to provide an output of the subtractor to either a first path or a second path according to the operation speed;
a low-pass filter provided on the first path, receiving an output of the subtractor provided to the first path by the switch, and removing a ripple component with respect to the sensed current;
a first delay compensation filter provided on the first path, receiving an output of the low-pass filter, and compensating for a delay caused by the low-pass filter;
a second delay compensation filter for compensating for a delay time caused by a difference between a time of sensing the current and a time of calculating and applying the operation speed; and
a resonance controller receiving the output of the second delay compensation filter and performing resonance control; and
an adder for outputting the target current by adding the output of the proportional-integral controller and the output of the resonance controller;
A power conversion device comprising a.
The method of claim 9, wherein the second delay compensation filter
A power conversion device that receives an output of the first delay compensation filter or an output of the subtractor provided to the second path by the switch.
10. The method of claim 9, wherein the switch is
When the operation speed falls within the low speed range, the power converter provides the output of the subtractor to the first path.
An air conditioner using a compressor, comprising:
a compressor motor for driving the compressor; and
a power converter for supplying AC power to the compressor motor;
including,
The power conversion device includes an inverter unit that outputs a current for driving a compressor motor and an inverter control unit that controls the inverter unit,
The inverter control unit,
Senses the current output from the inverter unit and calculates the operation speed of the compressor motor based on the sensed current. If the operation speed falls within the low speed range, a low-pass filter is applied in relation to the operation speed and delay compensation is performed. An air conditioner that generates a target current by performing

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