KR20100138370A - Speed control device of LSPM motor using inverter - Google Patents

Abstract

The present invention relates to a speed control device for an LSPM motor using an inverter, comprising: an input power supply for applying single-phase power, an inverter converting and outputting the power into three phases, an LSPM motor driving with the power output in the three phases; And a control unit electrically connected to the inverter to control a speed of the LSPM motor by converting a frequency of power output from the inverter.

By using the speed control device of the LSPM motor as described above, since the drive of the compressor is changed according to the mode selection, the power consumption of the refrigerator can be reduced as compared with the conventional compressor operating the same regardless of the mode selection.

Description

An apparatus for controlling velocity of a line start permanent magnet motor using an inverter

The present invention relates to a speed control device for an LSPM motor, and in particular, a speed control of an LSPM motor using an inverter capable of controlling the speed of an LSPM motor by using a three-phase power output from an inverter and converting a frequency of the three-phase power. Relates to a device.

In general, the refrigerator supplies cold air to the freezer compartment and the refrigerating compartment by a freezing cycle composed of a compressor, a condenser, a capillary tube, an evaporator, and a fan motor. In this case, the compressor compresses the low-temperature, low-pressure gas refrigerant into a high-temperature, high-pressure gas refrigerant, which is performed by the rotation of the compressor motor. BLDC motor is typically used as the compressor motor. The BLDC motor consists of a stator and a rotor in which three coils are wound, and alternately a high (H), a low (L), and an open (O) state power is applied to each coil. The magnetic force generated in each drive by rotating the rotor of the motor.

A control block diagram of a compressor using such a BLDC motor is shown in FIG. 1. As shown in FIG. 1, the compressor includes a power supply unit 1 into which commercial AC power is input, and a converter unit 2 converting AC power input from the power supply unit 1 into DC power. The inverter unit 4 is electrically connected to the converter unit 2 for converting the DC power output from the converter unit 2 into three-phase AC power to rotate the BLDC motor 3. The inverter unit 4 controls the operation of the BLDC motor 3 under the control of the control unit 5.

However, since the BLDC motor requires a position sensor for detecting the position of the permanent magnet embedded in the power conversion element and the rotor, there are a lot of control elements, which makes the structure of the refrigerator complicated and increases the manufacturing cost.

In order to solve this problem, a refrigerator driving a compressor using an LSPM motor has been studied. However, the LSPM motor rotates only at a synchronous speed by a certain frequency, and since it is a single phase motor, an unbalanced magnetic field is generated due to its structural characteristics. Accordingly, the LSPM motor has a disadvantage in that the efficiency of the motor is low and the starting characteristic is inferior to that of the three-phase motor.

An object of the present invention is to solve the problems as described above, to provide a speed control device of the LSPM motor using an inverter that can use a single-phase power source without the need for a separate power conversion element.

Another object of the present invention is to drive a LSPM motor using a three-phase power output from the inverter, and to provide a speed control device of the LSPM motor using an inverter that can control the rotational speed of the motor by converting the frequency of the output power It is.

Still another object of the present invention is to provide a speed control device for an LSPM motor using an inverter that can reduce a control element compared to a BLDC motor because an inverter that performs a function of converting a single-phase input to a three-phase output is used.

It is still another object of the present invention to provide a speed control apparatus for an LSPM motor using an inverter having improved efficiency and maneuverability compared to a single phase by using a three-phase power source in which each phase forms a balanced magnetic field.

In order to achieve the above object, the speed control device of the LSPM motor using the inverter according to the present invention is an input power for applying a single-phase power, an inverter for converting and outputting the power in three phases, the power output in the three phases And a control unit electrically connected to the driving LSPM motor and the inverter to control the speed of the LSPM motor by converting a frequency of power output from the inverter.

In addition, the present invention is characterized in that the LSPM motor drives a compressor for a refrigerator or an air conditioner.

In addition, the present invention includes a rotor in which the LSPM motor is rotatably installed inside the stator and a coil in which the coil is wound, and the rotor includes a plurality of conductors installed along an outer edge and a center of the rotor. It characterized in that it comprises a plurality of permanent magnets installed between the conductors.

In addition, the present invention is characterized by converting the frequency of the power output from the inverter as the frequency of the power output from the inverter in accordance with the cooling mode.

As described above, according to the speed control apparatus of the LSPM motor using the inverter according to the present invention, the effect that a single-phase power source can be used without requiring a separate power conversion element is obtained.

In addition, according to the speed control apparatus of the LSPM motor using the inverter according to the present invention, the LSPM motor can be driven by using the three-phase power output from the inverter, and the rotation speed of the motor can be controlled by converting the frequency of the output power. There is also an effect.

In addition, according to the speed control device of the LSPM motor using the inverter according to the present invention, the use of an inverter that converts a single-phase input into a three-phase output can be used to reduce the control element compared to the BLDC motor. .

Moreover, according to the speed control apparatus of the LSPM motor using the inverter which concerns on this invention, the effect that efficiency and mobility can be improved compared with a single phase by using the three-phase power supply which each phase forms a balanced magnetic field is obtained.

These and other objects and novel features of the present invention will become more apparent from the description of the present specification and the accompanying drawings.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention is demonstrated in detail according to drawing.

First, an example of the LSPM motor used in the speed control apparatus of the present invention will be described with reference to FIG. 2 is a schematic cross-sectional view showing an example of the LSPM motor used in the embodiment of the present invention.

As shown in FIG. 2, the LSPM motor 10 includes a stator 11, a coil 12, and a rotor 13. The stator 11 is fixed by a casing or shell (not shown) formed on the outside. A hole in which the rotor 13 is positioned is formed inside the stator 11, and teeth 11a are formed along a predetermined interval of the inner circumferential surface. Each of the teeth 11a is wound with a coil 12 to generate magnetic flux from an applied AC power source. The coil 12 is preferably formed in three phases.

In the inner hole of the stator 11, the rotor 13 is rotatably provided with an air gap therebetween. A shaft 13a is positioned at the center of the rotor 13 and is rotatably installed with respect to a casing or a shell via a bearing (not shown). A plurality of bar-shaped conductors 13b are inserted along the outer edge of the rotor 13. The conductors 13b are preferably made of an aluminum (Al) material having excellent conductivity and capable of die casting.

On the other hand, a plurality of permanent magnets 14 are installed in the rotor 13 around the outer side of the shaft 13a. The permanent magnets 14 are configured to generate a torque by interaction with the magnetic flux generated in the coil 12, and are generally configured to be symmetrical in polarity. However, those skilled in the art can recognize the permanent magnets 14 in various forms. Of course, it can be placed in).

Accordingly, when a current is applied to the coil 12 of the LSPM motor 10, the mutual rotation of the magnetic flux generated by the structure of the stator 11 and the induced current generated in the conductor 13b of the rotor 13 is achieved. By the action, the rotor 13 is started and rotated. In addition, when the rotor 13 reaches the synchronous speed, the LSPM motor 10 generates a torque caused by the permanent magnet 14 and a resonance (magnetic resistance) torque due to the structure of the rotor 13. The electron 13 can be rotated.

Next, a speed control apparatus of the LSPM motor will be described with reference to FIG. 3.

3 is a block diagram illustrating a speed control apparatus of an LSPM motor using an inverter according to an exemplary embodiment of the present invention.

As shown in FIG. 3, the speed control apparatus 20 of the LSPM motor according to the exemplary embodiment of the present invention includes an input power source 21, an inverter 23, an LSPM motor 10, and a controller 27. do. The input power source 21 supplies power to the inverter 23 in a single phase and may use a commercial power source of 220V. The inverter 23 converts the single-phase power applied from the input power 21 into three phases and outputs the three-phase power. The power output converted into the three phases drives the LSPM motor 10.

The rotation speed of the LSPM motor 10 is determined by the rated frequency, and when the frequency of the power output from the inverter 23 is converted, the rotation speed of the rotor 11 may also vary. For example, when a power source having a frequency of 50 Hz is input to the LSPM motor 10, the rotor 11 may rotate at a synchronous speed of 3600 rpm, and when the power source having a frequency of 60 Hz is input, the rotor ( 11) can rotate at a synchronous speed of 4000rpm.

The control unit 27 is electrically connected to the inverter 23. Under the control of the controller 27, a frequency-converted power is output from the inverter 23 to control the speed of the LSPM motor 10. The control unit 27 is electrically connected to the cooling mode selector 29. The controller 27 adjusts the speed of the LSPM motor 10 by converting the frequency of the power output from the inverter 23 according to the cooling mode. In this case, the cooling mode selector 29 includes a rapid cooling mode capable of rapidly cooling a cooling object and a continuous cooling mode capable of cooling the cooling object at a constant speed as compared with the rapid cooling mode.

[Table 1] below shows the change in the refrigeration capacity of the compressor according to the rotational speed using the BLCD motor.

Power / frequency
(V / Hz) Current (A) input Freezing capacity Performance Rotational speed change
(rpm) 220/60 0.39 96.1 133.6 161.7 1800 220/60 0.51 127.7 182.2 165.9 2400 220/60 0.62 156.5 225.3 167.4 3000 220/60 0.75 192.0 274.5 166.3 3600 220/60 0.84 214.0 304.5 165.5 4000

As shown in Table 1, it can be seen that the greater the rotation speed of the motor, the greater the freezing capacity.

Therefore, when the LSPM motor 10 is a motor for driving the compressor of the refrigerator, when the rapid cooling mode is selected, the frequency of the output power of the inverter 23 is converted to increase the rotation speed of the LSPM motor 10 to increase the rotation speed of the refrigerator. When the cooling capacity is increased and the continuous cooling mode is selected, the rotation speed of the LSPM motor 10 may be decreased to adjust the rotation speed of the LSPM motor 10 so that the cooling object is cooled for a longer time than the rapid cooling mode.

As a result, since the speed control device 20 of the LSPM motor according to the present invention changes the driving of the compressor according to the mode selection, the power consumption of the refrigerator can be reduced as compared to the conventional compressor that operates in the same manner regardless of the mode selection. have.

As mentioned above, although the invention made by the present inventor was demonstrated concretely according to the said Example, this invention is not limited to the said Example and can be variously changed in the range which does not deviate from the summary.

1 is a control block diagram of a compressor according to the prior art.

2 is a schematic cross-sectional view showing an example of the LSPM motor used in the embodiment of the present invention.

3 is a block diagram illustrating a speed control apparatus of an LSPM motor using an inverter according to an exemplary embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

 10: LSPM motor 11: Stator

11a: Tooth 12: coil

13: rotor 13a: shaft

13b: conductor 14: permanent magnet

20: speed control device 21: input power

23: inverter 27: control unit

29: cooling mode selector

Claims (4)

An input power source for applying single phase power; An inverter for converting and outputting the power into three phases; An LSPM motor driven by the power output in the three phases; And And a control unit electrically connected to the inverter to control the speed of the LSPM motor by converting a frequency of power output from the inverter. The method of claim 1, wherein the LSPM motor A stator wound with coils; And It includes a rotor rotatably installed inside the stator, The rotor A plurality of conductors installed along the outer edge; And And a plurality of permanent magnets installed between the center of the rotor and the conductors. The method of claim 2, The LSPM motor is a speed controller of the LSPM motor, characterized in that for driving a compressor for a refrigerator or air conditioner. The method of claim 3, wherein the control unit Speed control device of the LSPM motor, characterized in that for converting the frequency of the power output from the inverter in accordance with the cooling mode.

Images