JPH0345144A - Rotational position detector for compressor motor - Google Patents

Abstract

PURPOSE:To enable employment of general use magnetism detecting element by arranging the magnetism detecting element on a bottomed cylinder inserted, while maintaining air-tightness of an enclosed container, from the outside of the enclosed container toward a permanent magnet arranged on a disc movable together with a rotary shaft. CONSTITUTION:Since a compression element 4 rotates together with a rotor 6 through a crankshaft 2, rotational position of the compression element 4 can be detected when the rotational position of the rotor 6 is detected. Position detector comprises a magnet 23 and a Hall element 24 adhered to a disc 22. Positional relation between the magnet 23 and the Hall element 24 is set such that the Hall element 24 detects magnetism and varies its output when the rotational position indicates 0 deg.. The Hall element 24 is arranged on a bottomed pipe 50, in the rear thereof, inserted from the outside of enclosed container 1 for compressor. The pipe 50 is welded to the enclosed container 1 so that high pressure gas does not leak into the compressor. By such arrangement, a general use magnetism detecting element can be employed without contacting with working refrigerant.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a compressor in which an induction motor and a compression element rotationally driven by the rotor of the induction motor are housed in the same case, and particularly relates to This invention relates to a detection circuit that detects the rotational position of this induction motor.

(Example) Conventional technology In general, there is a device for detecting the rotational position of a motor for a compressor as described in Japanese Patent Application Laid-Open No. 63-23585. The rotational position of the rotor was detected by directly connecting a gear or encoder to the rotating shaft and installing a sensor to detect the pulses generated by the rotation.

(c) Problems to be Solved by the Invention In the motor rotational position detection device configured as described above, the sensor must be installed directly inside the compressor, and therefore the sensor must be There was a problem with pressure characteristics, and the life of this sensor could not be ensured sufficiently.Therefore, there was a problem that the life of the compressor itself was shortened.

In addition, products with improved anti-preion properties have been developed, but they have not had a sufficiently long lifespan.

In order to solve these problems, the present invention provides a rotational position detection device that does not cause problems such as freon resistance even when a general-purpose sensor is used.

(2) Means for Solving the Problems The present invention provides a compressor that is constructed by accommodating an electric motor and a compression element connected to the electric motor via a rotating shaft and driven by the rotating shaft in a single closed container. In the machine, there is a disk that rotates together with the rotating shaft, a permanent magnet mounted on the disk, a recessed part of the sealed container facing the permanent magnet, and a recess that can detect the magnetism of the permanent magnet. The rotor includes a magnetic detection element provided in the magnetic detection element, and a control section that determines the rotational position of the rotor from changes in the output of the magnetic detection element.

Also, a disk that rotates together with the rotating shaft, a permanent magnet mounted on the disk, and a bottomed cylinder that is inserted from the outside of the sealed container toward the permanent magnet so that the airtightness of the sealed container is maintained. The cylinder is equipped with a magnetic detection element provided in the cylinder so as to be able to detect the magnetism of the permanent magnet, and a control section that determines the rotational position of the rotor from changes in the output of the magnetic detection element.

Further, the cylinder is inserted from a direction along the axial direction of the rotating shaft.

Further, the cylinder is inserted from a direction perpendicular to the axial direction of the rotating shaft.

Further, the permanent magnet is attached to a position on the disk corresponding to a predetermined rotational position of the compression element.

Furthermore, permanent magnets are attached to the disk at positions corresponding to a plurality of predetermined rotational positions of the compression element.

The device also includes an electrical component attached to the outer wall of the closed container near the opening of the tube, and a single cover that covers the electrical component and the opening of the tube at the same time.

(*) Function: In the rotational position detection device configured as described above, a general-purpose sensor can be used for position detection without considering the pleon resistance of the compressor.

(f) Examples Examples of the present invention will now be described based on the drawings. FIG. 1 is a sectional view of the compressor. In this figure, 1 is a closed container, and a compression element 4 and a three-phase induction motor 3 are housed inside. The three-phase induction motor 3 includes a stator 5 around which three-phase windings are wound, and a rotor 6 that rotates by a magnetic field generated from the stator 5.
It consists of. A compression element 4 is connected to the shaft 13 of this rotor. The compression element 4 includes a crank part 14 that rotates using the shaft 13 as the crankshaft 2, and a roller 8 that rotates within the cylinder 7 by the crank part 14.
, an upper bearing portion 10 and a lower bearing portion 11 that close the opening of the cylinder 7, and a cup muffler 1 attached to the upper bearing portion.
It is composed of 2. A vane 9 is in contact with the roller 8 and divides the inside of the cylinder 7 into a high pressure chamber and a low pressure chamber. Reference numerals 16 and 17 denote balancers, which are provided to be dynamically or statically balanced with the crank portion 14 of the crankshaft 2. 18 is a discharge pipe, which is attached to the upper side of the closed container 1.

FIG. 2 is a cross-sectional view taken along the line -■ of the compressor shown in FIG.

In this figure, 19 is a discharge port, 20 is a suction boat, and spaces 21 and 22 in the cylinder 7 are respectively defined as a high pressure chamber and
It is separated into a low pressure room. Further, the roller 8 rotates in the direction of the solid line arrow in FIG. 2, and the contact position where the roller 8 contacts the cylinder 7 is expressed as a rotational position from 0 to 360 degrees. In the state shown in FIG. 2, the contact point between the roller 8 and the cylinder 7, that is, the rotational position of the crankshaft 2 (shaft 13) is at 180 degrees.

FIGS. 3 and 4 are a sectional view and a top view of main parts showing a state in which a position detector for detecting the rotational position of the compression element 4 is attached to an actual compressor. In this figure, the compression element 4 rotates simultaneously with the rotor 6 via the crankshaft 2 (shaft 13 of the rotor 6), so in reality, if the rotational position of the rotor 6 is detected, the rotational position of the compression element 4 can be detected. The 0 position detector that can detect the
It consists of 4. The disk 22 is attached to the shaft 13 by bolts 25 so that the center of rotation thereof coincides with the disk 22 . The positional relationship between the magnet 23 and the Hall element 24 is such that the Hall element 24 detects magnetism and changes the output when the rotational position shown in FIG. 4 (rotor) changes its output at each rotational position of "0" degree.Hall element 2
4 is a bottomed vibrator 5 from the side of the airtight container 1 of the compressor.
0 (cylindrical or polygonal) is inserted and provided at the back of this vibrator 50. Further, this vibrator 50 is welded to the closed container 1 to prevent the high pressure gas inside the compressor from leaking. Note that 26 is a balance weight that corrects the weight balance of the disc caused by attaching the Hall element 24.

The vibrator 50 is made of copper, for example, and has a diameter large enough to accommodate the Hall element 24, and has a bottomed shape by welding a lug to one end. Further, after the Hall element 24 is attached to a substrate large enough to fit into the vibrator 50, the vibrator 50 is mounted together with this substrate.
is inserted into.

Incidentally, FIG. 5 is a top view of the disk 22.

FIG. 6 is a control circuit diagram for controlling the operation of the compressor shown in FIGS. 1 to 3. In this figure, 27 to 29 are stator windings of the induction motor 5, which are star-connected.

By supplying three-phase alternating current to the stator windings 27 to 29, the magnet 23 with the rotor 5 attached to the rotor disk 5 rotates. Therefore rotor 5 (compression element)
The output of the Hall element 24 changes every time it rotates, and the position detection circuit 30 converts this change into a signal that is sent to the control unit 31.
Output to. 32 to 37 are switching elements that perform ON10FF operation, and are connected in a three-phase bridge shape.
The DC power supplied from the DC power supply 39 to the three-phase stator windings 27 to 29 is converted into three-phase AC power and output. These switching elements (transistor elements, F
Semiconductor switching elements such as ET elements and GTo elements)
32 to 37 are used for discharging accumulated charges and stator winding 27, respectively.
A diode is connected forming a circulating circuit through which the circulating current generated at .about.29 flows. Note that the DC power source 39 may be either rectified and smoothed AC power (a commercial power source is also possible) or DC power from a battery. Further, the ON10FF operations of the switching elements 32 to 37 are controlled by a signal from the control section 31 provided via the base drive circuit 38. This control section is mainly composed of a CPU, RAM, ROM, I10 interface, etc., and calculates a frequency based on the speed signal from the speed command circuit 40, and supplies AC power at this frequency to the stator windings 27 to 29. Switching element 3
2 to 37 0N10FF operations are controlled based on PWM theory. Hereinafter, 0N10FF control of the switching elements 32 to 37 performed to obtain AC power at the calculated frequency will be described. FIG. 7 shows switching elements 32 to 3.
FIG. 7 is an explanatory diagram showing a process of creating an O N10 F F signal to be supplied to the device 7 based on PWM theory. The switching elements 32 to 3 modulate the sfn waveform (there are 3 waveforms because there are 3 phases in FIG. 7) and the triangular wave having a frequency equal to the desired frequency.
7 0N10FF signals are obtained.

At this time, the resolution of the AC waveform output from the bridge circuit (ON10 of the switching element) is determined by the frequency of the triangular wave.
FF state switching period) is determined. In other words, the higher the frequency of the triangular wave, the better the resolution, but on the other hand, if the switching speed of the switching element is exceeded, the switching element becomes inoperable. Set.

As can be seen from this figure, if the amplitude of the triangular wave and the amplitude of the sine wave are set appropriately, each switching element will have a 0N10
FF time changes. As a result, as the ON time of the switching element becomes longer, the voltage amplitude of the AC power output from the bridge circuit becomes larger. That is, the output voltage becomes higher. Note that at this time, the frequency of the triangular wave may be changed with respect to the frequency of the sine wave. Note that the generation of the switching signal is not limited to the method described above, but any method may be used as long as it can output AC power of a desired frequency and can arbitrarily change the output voltage of this AC power during one cycle of AC.

Therefore, when using such a waveform generation method, the AC power P becomes f
(-output frequency), V (=output voltage), and Ph (-output phase). That is, based on such conditions, the switching elements 32 to 37 are 0N10
The FF signal is calculated. Note that f is the frequency calculated from the speed signal given from the speed command circuit, and the basic value of ■ is determined based on the value of f so that it becomes V/f' - a constant value. The values are set such that the efficiency of operation of the induction motor or compressor is good at each frequency. When the value of Ph changes from 0 to 360 degrees, one cycle of alternating current power is output. If the advancement amount ΔPb of Ph is increased, the resolution in one cycle will deteriorate, and if this value is decreased, the resolution will be improved. The optimum value of ΔPh for each frequency is set in advance based on the relationship.

FIG. 8 shows the control unit 3 when outputting AC power with frequency f.
1 is a flowchart showing the operation of FIG.

In this flowchart, in step S1, it is first determined whether the frequency f has been changed.

That is, it is determined whether or not there has been a change in the speed signal given from the speed command circuit 40. When there is a change in the frequency f, the process proceeds to step S2, where V (basic value of output voltage) and ΔPh (phase advance amount) are calculated and changed. Next, the process advances to step S3. In this step, it is determined whether there is a signal from the position detection circuit. That is, it is determined whether the compression element of the compressor (rotor of the induction motor) has reached the "0" rotational position. If this signal is present, the process advances to step S4. In this step, the phase Ph is set to “0”
At the same time, the rotational speed N of the rotor is calculated from the previously input signal and the current input signal. Further, if there is no signal in step S3, the process advances to step S5. In this step, the value of the phase Ph is advanced by ΔPh. Then, in step S6, the phase P
It is determined whether h is between the phases phh and Phi. When the phase Ph satisfies the conditions of step S6, the process proceeds to step S7, where the value of ■ is increased by +VU (approximately 20% relative to the value of V), and the value of f is increased by +fU (5 to 5% relative to the value of f). 7%) and increase the pH value by PhU (about 10 degrees). If the condition in step S6 is not satisfied, the process proceeds to step S8, where the value of ■ is decreased by -VD (approximately 10 to 20% with respect to the value of V), and the value of f is reduced to -f'
D (approximately 5 to 7% relative to the value of f).

By executing steps 86 to S8, when the rotor is in the rotational range between the rotational position corresponding to the phase Phi and the rotational position corresponding to the phase phh, the stator windings, that is, the supply to the motor of the compressor. As the frequency and voltage of the alternating current power increases, the driving torque of the motor increases. Further, at other times, the driving torque is reduced. Therefore, the torque can be increased when the compression element is in the compression process and the electric motor requires a large torque. Note that the values of Phi and phh will be described later. Next, the process advances to step S9, and in this step, the rotational speed N of the rotor calculated in step S4 is set to a value smaller by a predetermined value (RO
LL). The ratio of the value of ROLL to N may be different for each frequency, or may be a constant ratio.When the 0 rotation speed N is small (proceed to step S10. In this step, V.

The values of f and Ph are each corrected to the + side. Then step S
In this step, it is determined whether the rotational speed N of the rotor calculated in step S4 is a value (ROLH) larger than the value given from the speed command circuit by a predetermined value. The ratio of the value of ROLH to N may be different for each frequency, or may be a constant ratio or a constant value. When the zero rotation speed N is large, step 512
In this step, the values of v, r, and ph are each corrected to the negative side. The correction width divided into steps S10 and S12 is 0.1 to 0.5 volts in voltage and 0 in frequency.
．． The frequency is about 1 to 0.5 Hz.

Step 513 is a switching signal output step. In this step, the switching elements 32 to 37 are kept in the 0N10FF state for a certain period of time (-period time/360/ΔPh) based on the values of r, V, and Ph obtained in the above steps. be. (
When the minimum unit of Ph is 12 degrees), for example, the switching signal for one period based on this flowchart is as shown in FIG. 7 described above.

FIG. 9 is a voltage waveform diagram of AC power obtained when the flowchart shown in FIG. 8 is executed. This voltage waveform V2
7. Stator winding 27-2 of V2B, V29 induction motor
- For example, the voltage waveform is the voltage supplied to the 9th
A description will be given of the phase state shown in the figure. "0" degree in the figure is when a signal is output from the position detection circuit. That is, when the position of the magnet provided on the rotor and the Hall element match. The position of this phase Phi is determined from the time of one cycle during which the phase angle is determined from the rotational speed of the phi rotor and the time corresponding to the rotational position. ), V=V+VU, r=r+rUS
Ph-Ph+PhU1. m, the voltage waveform is raised as shown by the dotted line. This dotted line voltage waveform has an output voltage of VUCV compared to the basic voltage waveform (solid line voltage waveform)
The frequency is f'UHz higher than the fundamental frequency, and the phase is advanced. That is, the phase angle Phi of the voltage waveform shown by the dotted line is about 10 degrees ahead of the phase angle Phl of the voltage waveform shown by the solid line. This phase angle is Ph1-
The period between Phh corresponds to the compression process of the compression element, and is a section that requires a large torque.

FIG. 10 is a vibration characteristic diagram showing the vibration state of the compressor when the compressor is being driven. This vibration is determined from the output of an acceleration sensor attached to the compressor. The operating conditions at this time were when the frequency of AC power supplied to the stator windings was 30 Hz. In this figure, the OFF side (to the left of the dotted line) is when the @ control method according to the present invention is not used, and the ON side (to the right of the dotted line) is when the control method of the Tuki invention is used. It can be seen that by using the control method of the present invention, the amplitude of vibration is reduced from LOFF to LON (reduced to about 1/3). In other words, the vibration is reduced.

Figure 12 shows the phase angle P when the compressor is driven at 30Hz.
It is a characteristic diagram which shows the relationship between h1, Phh, and a vibration waveform. In this figure, the waveform of i is the vibration waveform when the control method of the present invention is not used, and the vibration amplitude peaks at 130 degrees at the 0 phase (approximately equal to the rotational position) and at 270 degrees. . The waveform of i is a vibration waveform when Ph1=100 degrees and Phh-250 degrees using the control method of the present invention. i is the same < Ph1 = 130 degrees, ph
This is the vibration waveform when h is set to -270 degrees, and ~ is also the vibration waveform when Phi is 150 degrees and Pbh is 300 degrees. From these results, the PHL type is about 130 degrees, p
hh is approximately 270 degrees, that is, the values of Phi and phh are appropriate near the phase where the vibration amplitude peaks when the control method according to the present invention is not used (when the compression element of the compressor is performing the compression process). This is a value that can reduce the vibration of the compressor. Therefore, as the vibration is reduced, the noise can also be reduced at the same time.

In the above embodiment, the phase (rotational position) is Ph1, Ph
Although the torque of the induction motor was increased by one step during h, the torque may be increased by two steps in this section,
Alternatively, the torque may be gradually increased including the sections before and after this section.

FIGS. 12 and 13 are a sectional view and a top view of main parts showing another embodiment of the rotational position detection device. The difference from the sectional view shown in FIG. 3 is that a bottomed pipe 42 is inserted from the upper part of the closed container 1, from the discharge pipe 18 side, along the shaft 13 of the rotor 6.

42 is a Hall element, 43 is a sealed terminal of the compressor, and 44 is an attachment bottle, which is attached with a resin cover so as to cover the sealed terminal and the opening of the vibrator 41. By covering the pipe 42 with a cover, it is possible to prevent dirt and rainwater from entering the vibrator 41.

FIGS. 14 and 15 are top views of the disk showing other states in which permanent magnets are attached to the disk, respectively. In FIG. 14, permanent magnets 45 and 46 are installed at positions that output signals when the rotor rotational position reaches 130 degrees and 270 degrees. When a permanent magnet is attached in this manner, it is sufficient to change the output voltage of the AC power in accordance with the change in the output of the Hall element, eliminating the need for rotational position calculation and simplifying the control device. Also, Figure 15 shows the permanent magnet 47.4
8 is attached at the rotational position of the rotor of 0 degrees and 180 degrees. By attaching a permanent magnet to such a position, an accurate rotational position can be calculated by correcting the rotational position of the rotor twice during one rotation.

<g) Effects of the Invention In the rotor position detection device of the present invention, a disk is mounted to rotate together with the rotating shaft, a permanent magnet is mounted on the disk, and a part of the sealed container is turned toward the permanent magnet. A recessed part or a bottomed cylinder inserted from the outside of the sealed container so that the airtightness of the sealed container is maintained, and this recessed part,
Alternatively, since the magnetic detection element is attached to the cylinder so as to be able to detect the magnetism of the permanent magnet, the magnetic detection element does not come into direct contact with the working refrigerant in the compressor, and a general-purpose magnetic detection element can be used.

[Brief explanation of drawings]

Figure 1 is a sectional view of a compressor using the control method of the present invention, Figure 2 is a cross-sectional view of the compressor shown in Figure 1, and Figure 3 is an actual compressor with a position detector attached. 4 is a top view of the compressor shown in FIG. 3, FIG. 5 is a top view of the disk shown in FIG. 3, and FIG. 6 is a sectional view of the compressor shown in FIG. Control circuit diagram for controlling the operation of the compressor shown in Fig. 7.
The figure is an explanatory diagram showing the 0N10FF signal of the switching element, Figure 8 is a flowchart showing the operation of the control section shown in Figure 6, and Figure 9 is an illustration of the AC power obtained when the flowchart shown in Figure 7 is executed. Voltage waveform diagram, Figure 10 is a vibration characteristic diagram showing the vibration state of the compressor when the compressor is being driven, Figure 11 is a vibration characteristic diagram when the compressor is being driven at 30Hz, Figure 12 is a vibration characteristic diagram showing the vibration state of the compressor when the compressor is being driven. The figure is a sectional view of the main parts of a compressor of another embodiment showing the installation state of the Hall element, and FIG.
2 is a top view of the compressor shown in FIG. 2, FIG. 14 is a top view showing another embodiment of the disk attached to the rotor, and FIG.
The figure is a top view of a disk showing still another embodiment attached to a rotor. DESCRIPTION OF SYMBOLS 1... Compressor, 4... Compression element, 5... Induction motor, 6... Rotor, 23... Magnet, 24... Hall element, 27-29...
・Stator winding, 30... position detection circuit, 31...
-Control unit, 32-37...Switching element, 40...Speed command circuit, 0...Pipe.

Claims (7)

[Claims] (1) In a compressor in which an electric motor and a compression element connected to the electric motor via a rotating shaft and driven by the rotating shaft are housed in a single sealed container, a disk that rotates together with the rotating shaft and , a permanent magnet mounted on the disc, a recessed part of the sealed container facing the permanent magnet, a magnetic detection element provided in the recessed part to detect the magnetism of the permanent magnet, and 1. A rotational position detection device for a compressor motor, comprising: a control section that determines the rotational position of a rotor from changes in the output of a magnetic detection element. (2) In a compressor in which an electric motor and a compression element connected to the electric motor via a rotating shaft and driven by the rotating shaft are housed in a single sealed container, a disk that rotates together with the rotating shaft and , a permanent magnet mounted on this disc, a bottomed cylinder inserted from the outside of the sealed container toward the permanent magnet so as to maintain the airtightness of the sealed container, and a magnetism of the permanent magnet applied to this cylinder. 1. A rotational position detection device for a compressor motor, comprising: a magnetic detection element provided to enable detection; and a control unit that determines the rotational position of a rotor from changes in the output of the magnetic detection element. (3) The rotational position detection device for a compressor motor according to claim 2, wherein the cylinder is inserted from a direction along the axial direction of the rotating shaft. (4) The rotational position detection device for a compressor motor according to claim 2, wherein the cylinder is inserted from a direction perpendicular to the axial direction of the rotating shaft. (5) The rotational position detection device for a compressor motor according to claim 2, wherein the permanent magnet is attached to a position on the disk corresponding to a predetermined rotational position of the compression element. (6) The rotational position of the compressor electric motor according to claim 5, characterized in that permanent magnets are attached to the disk at positions corresponding to a plurality of predetermined rotational positions of the compression element. Detection device. (7) Patent claims 3 and 4, characterized by comprising an electrical component attached to the outer wall of the airtight container near the opening of the tube, and a single cover that simultaneously covers the electrical component and the opening of the tube. A rotational position detection device for a compressor electric motor as described above.