WO1999005779A1

WO1999005779A1 - Method and device for controlling drive of air conditioner

Info

Publication number: WO1999005779A1
Application number: PCT/JP1998/003258
Authority: WO
Inventors: Yoriyuki Takekawa; Nobukazu Takagi; Yuji Kawasaki
Original assignee: Zexel Corporation
Priority date: 1997-07-24
Filing date: 1998-07-22
Publication date: 1999-02-04
Also published as: JPH1146494A

Abstract

A method for controlling the drive of an air conditioner (100) provided with a compressor (1) having a compressing mechanism (10) driven by means of a DC brushless motor (30), which comprises simultaneously controlling a plurality of prescribed switching elements in the first switching element group (42-44) and a plurality of prescribed switching elements in the second switching element group (45-47) of a commutator circuit (41) which supplies driving currents to driving windings (31-33) of the DC brushless motor (30) in response to a stop command signal (Sc) to reach energized states by means of a stop control signal (SS) from a stop control signal generating section (58). As a result, the driving windings (31-33) are short-circuited and the reverse rotation of the compressor (1) caused by the difference between the input pressure and the output pressure of the compressor (1) can be prevented without providing the compressor (1) with any reverse rotation preventing mechanism.

Description

Description Air-conditioner drive control method and device

The present invention relates to a drive control method and apparatus for an air conditioner including a compressor driven by a DC brushless motor. Background art

An air conditioner is known in which a compression mechanism is driven by a DC brushless motor, but according to this configuration, when the operation of the DC brushless motor is stopped, the pressure difference between the suction side and the discharge side of the compression mechanism is reduced. Reversal of the compressor occurs, causing noise and damaging the compressor. In order to solve this problem, Japanese Patent Application Laid-Open No. 7-97994 discloses that a switch and a resistor are separately provided, and when the operation is stopped, the switch is closed and the coil of the motor is short-circuited by the resistor. A technique for generating a braking force for preventing reverse rotation is disclosed. Further, in Japanese Patent Application Laid-Open No. 8-2199526, when the operation of the compressor is stopped, a rotation speed reduction command signal is output in the evening, and the rotation speed of the compressor is gradually reduced to reduce the compression speed. A configuration is disclosed in which the compressor is stopped at a timing when the difference between the inlet pressure and the outlet pressure of the compressor becomes equal to or less than a predetermined value.

However, when a switch and a resistor are separately provided and a motor coil is short-circuited by this resistor when the operation is stopped, a braking force for preventing reverse rotation is disclosed in Japanese Patent Application Laid-Open No. Hei 7-99794. According to the configuration in which the components are generated, another problem arises in that the number of components increases, which leads to an increase in cost. On the other hand, as disclosed in Japanese Patent Application Laid-Open No. 8-2199526, when the operation of the compressor is stopped, its rotational speed is reduced one by one to reduce the inlet pressure and the outlet pressure of the compressor. According to the configuration in which the difference between the two is set to zero, not only is the malfunction that the operation of the compressor does not stop immediately even when a stop command is issued, but also the power consumption increases. Also, the compressor Although a configuration in which a reverse rotation preventing mechanism is provided is also known, in this case, there is a problem that the configuration of the compressor becomes complicated and the cost increases.

An object of the present invention is to provide an air conditioner drive control method and apparatus that can solve the above-described problems in an air conditioner including a compressor driven by a DC brushless motor.

Another object of the present invention is to prevent reverse rotation when the operation of the compressor is stopped without causing the above-described problems in the prior art, without providing a reverse rotation prevention mechanism in the compressor. An object of the present invention is to provide a drive control method and apparatus for an air conditioner having a compressor driven by a DC brushless motor. Disclosure of the invention

According to the present invention, a DC brushless motor including a magnet rotor and a set of drive windings; a compressor having a compression mechanism driven by the DC brushless motor; A first switching element group and a second switching element group for commutating a drive current from a DC power supply to the drive winding; and each of the first and second switching element groups is rotated. Circuit means for rotating and driving the DC brushless motor by on / off control in accordance with the rotational position of the motor, wherein a stop command signal for the DC brushless motor is provided. And stops the on / off control of the switching element in response to the control signal, and switches the plurality of one of the first or second switching element group. The quenching device simultaneously conductive facedown state, thereby method as the least short-circuit state of one drive winding of the set of drive winding is provided.

In the operation mode of the air conditioner, the switching elements of the first and second switching element groups are turned on and off in accordance with the position of the rotor, and the drive current flowing through one set of drive windings is controlled. The switching generates a rotating magnetic field. As a result, the magnet rotor rotates, and the compression mechanism is rotationally driven by the DC brushless motor. On the other hand, when a stop command signal is given, the on / off control is stopped and the first switching Control is performed so that a plurality of switching elements of the element group or a plurality of switching elements of the second switching element group are simultaneously turned on. As a result, at least one drive winding is short-circuited, and a braking force can be applied to the rotation of the magnet rotor.

Here, in addition to the configuration in which the required plurality of switching elements are completely turned on, the configuration may be such that shoving is performed and intermittently turned on to limit the current flowing through the drive coil due to a short circuit.

In this way, a completely or intermittently short-circuiting the drive winding that is still rotating exerts a braking force on the rotation of the magnet rotor, thereby reducing the rotation of the DC brushless motor. As a result, it is possible to effectively prevent the compressor from rotating in reverse due to the input / output pressure difference of the compressor that occurs at the time of the DC brushless motor overnight stop command, and prevent the compressor from being damaged. it can. If the input / output pressure difference at the time of the compressor rotation stop command is large, the compressor will overcome the above-mentioned braking force acting on the DC brushless motor and rotate slightly in the reverse direction. This has the effect of reducing the input / output pressure difference of the machine and facilitating restarting.

Another feature of the present invention is a drive control device for an air conditioner including a compressor having a compression mechanism driven by a DC brushless motor including a magnet rotor and a set of drive windings. A DC power supply; a first switching element group connected between one output of the DC power supply and the set of drive windings; the other output of the DC power supply; and the set of drive windings A second switching element group connected between the first and second switching elements, a position detection circuit for detecting a rotational position of the magnet rotor, and a detection result of the position detection circuit. Turning on each switching element of the first and second switching element groups in order to commutate the drive current supplied from the DC power supply to the drive winding so that a rotational force is applied to the rotor in response to the current; Commutation control signal for off control A position feedback drive signal generating means for generating; and a stop control means for simultaneously controlling one of the plurality of switching elements of the first and second switching element groups to a conduction state. For brushless motor The output of the commutation control signal from the position feedback drive signal generating means is stopped in response to a stop command signal, and the plurality of switching elements are simultaneously controlled to be conductive by the stop control means. It is in.

Before the output of the stop command signal, the switching elements of the first switching element group and the second switching element group are turned on and off by the commutation control signal, and the drive current flowing through one set of drive windings is controlled. The switching generates a rotating magnetic field, which rotates the magnet rotor, and drives the compression mechanism to rotate. On the other hand, when the stop command signal is given, the output of the commutation control signal is stopped, the on / off control for each switching element is stopped, and the first or second switching is performed by the stop control means. A plurality of switching elements of the element group are simultaneously controlled to be conductive. As a result, at least one drive winding is short-circuited, and a braking force can be applied to the rotation of the magnet rotor.

As described above, the rotation of the magnet rotor is suppressed by the short-circuiting of the drive windings, and the rotation of the DC brushless motor is reduced. The compressor can be effectively prevented from rotating in the reverse direction, and the compressor can be prevented from being damaged. If the input / output pressure difference at the time of the compressor rotation stop command is large, the compressor will overcome the above-mentioned braking force acting on the DC brushless motor and rotate slightly in the reverse direction. This has the effect of reducing the input / output pressure difference of the machine and facilitating restarting.

ADVANTAGE OF THE INVENTION According to this invention, it can prevent reverse rotation of a compressor at very low cost, and can suppress generation | occurrence | production of noise and damage by reverse rotation. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a system diagram showing one embodiment of an air conditioner according to the present invention.

FIG. 2 is a schematic vertical sectional view showing a compression mechanism of the scroll-type electric compressor shown in FIG.

FIG. 3 is a schematic longitudinal sectional view taken along the line BB shown in FIG. FIG. 4 is a circuit diagram showing a circuit configuration of the DC brushless motor shown in FIG. 1 and its drive control device.

FIG. 5 is a detailed circuit diagram of the position detection circuit shown in FIG.

FIG. 6 is a waveform diagram of each signal for explaining the commutation control of the drive current in the drive control device shown in FIG.

FIG. 7 is a flowchart showing a control program for realizing a function equivalent to the function of the control unit shown in FIG. 4 by using a micro-combination system. BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a system diagram showing a schematic configuration of an embodiment of an air conditioner using a drive control device according to the present invention. As shown in Fig. 1, the air conditioner 100 is provided with a scroll-type electric compressor 1, a four-way switching valve 2, an outdoor heat exchanger 3, a throttle mechanism 4, an indoor heat exchanger 5, etc. A known heat pump cycle is configured, and the refrigerant circulates during a cooling operation as indicated by a solid line arrow, and circulates during a heating operation as indicated by a broken line arrow.

The compressor 1 includes a scroll-type compression mechanism 10 and a DC brushless motor 30 built in a closed container 1C. The DC brushless motor 30 is driven and controlled by the drive control device 40 to which DC power is supplied from the DC power source B. A schematic configuration of the scroll-type compression mechanism 10 is shown in FIGS. 2 and 3. Numeral 1 1 denotes a fixed scroll, which is composed of an end plate 1 ia, a spiral wrap 11 b erected on the inner surface thereof, and a peripheral wall 11 c surrounding the wrap. Reference numeral 12 denotes an orbiting scroll, which is provided on an end plate 12a and an inner surface thereof, and includes a spiral wrap 12b having substantially the same shape as the spiral wrap 11b. The fixed scroll 11 and the orbiting scroll 12 are decentered by a predetermined distance, and their phases are shifted by 180 ° to engage each other. One compression chamber 13 is formed. A drive bush 15 is rotatably fitted into a cylindrical boss 14 protruding from the center of the outer surface of the end plate 12 a of the orbiting scroll 12 via a bearing 16. An eccentric pin 19 that projects eccentrically from the end surface of the rotary shaft 18 by a predetermined distance from the end face of the rotary shaft 18 is fitted into a slide hole 17 formed in the drive bush 15. When the rotating shaft 18 rotates, this rotational force is transmitted from the eccentric pin 19 through the slide hole 17 to the drive bush 15, and further, through the bearing 16 and the boss 14. It is transmitted to 1 and 2. Thus, the orbiting scroll 12 orbits in a circular orbit around the axis of the rotating shaft 18 with a predetermined radius around the axis of the rotating shaft 18 in a state where the orbiting scroll 12 is prevented from rotating by a rotation preventing mechanism (not shown).

As a result, the gas wraps around the outer ends of the spiral wraps 1 lb and 1 2b and the opposite wrap.

It is taken into the compression chamber 13 from the gap between the back side of 12b and 11b, and the compression chamber 13 moves toward the center of the spiral while reducing its volume. Accordingly, the gas in each compression chamber 13 is gradually compressed, and when each compression chamber 13 communicates with the central discharge chamber 21, it merges and is discharged from the discharge port 22.

A valve chamber 26 is formed in the middle of the discharge port 22, and a free check valve 23 is disposed in the valve chamber 26. When the gas pressure is applied from the upstream side of the discharge port 22, the check valve 23 abuts on the second valve seat 24 on the downstream side to open the discharge port 22, and the downstream of the discharge port 22. When the gas pressure is applied from the side, it comes into contact with the first valve seat 25 on the upstream side and closes the discharge port 22.

Next, the DC brushless motor 30 and the drive control device 40 will be described with reference to FIG. In the present embodiment, the DC brushless motor 30 includes a three-phase Y-connected A-phase drive winding 31, a B-phase drive winding 32, and a C-phase drive winding 33. And a set of drive windings and a magnet rotor 3 4. Since the DC brushless motor 30 itself has a known configuration, a detailed description of its structure is omitted.

The drive control device 40 for controlling the drive of the DC brushless motor 30 includes a commutator circuit 41 for commutating the drive current from the DC power source B to the drive windings 31 to 33. ing. The commutator circuit 41 connects each terminal of the drive windings 31 to 33 with direct current. A switching transistor 42 to 44 that constitutes a first switching element group connected to the positive terminal of the power source B, and a second terminal that connects each terminal of the drive windings 31 to 33 to the negative terminal of the DC power source B It has a known circuit configuration in which the switching transistors 45 to 47 and the diodes D1 to D6 constituting the above switching element group are connected as shown.

Position feedback drive signal generator 5 1 is outputted from the position detecting circuit 6 0 to be described later, a set of sensorless signal ZA indicating the occasional position of the magnet rotor 3 4, Z _B, in response to Z _c, One set of switches for turning on and off the switching transistors 42 to 47 in order to generate the rotating magnetic field required to rotate the magnet rotor 34 by one set of drive coils 31 to 33. Commutation control signals A u, B _u , Cu, A _L , B _l , C

This is a circuit for generating L.

The bases of the switching transistors 42 to 47 are connected to the commutation control signals A _u and A _u from the position feedback drive signal generator 51 of the control unit 50 via the corresponding OR gates 52 to 57. Bu, Cu, A, B _L , C _L are provided. The switching transistors 42 to 47 are turned on / off in accordance with the commutation control signals A u to CL, respectively, whereby commutation of the drive current from the DC power supply B to the drive windings 31 to 33 is performed. Thus, the magnet rotor 34 is rotationally driven by the rotating magnetic field generated thereby.

The position detection circuit 60 determines the rotational position of the magnet rotor 34 from the back induced voltage induced in each of the drive windings 31 to 33 by the rotation of the magnet rotor 34, and determines the result. sensorless signal Z _a shown, Z _B, and outputs the Zc, sensorless signal Z _a, Z _B, Zc is fed to the position feedback drive signal generator 5 first control Yuni' bets 5 0. FIG. 5 shows a detailed circuit diagram of the position detection circuit 60. The first differential amplifier circuit 61, is the terminal voltage V _B TogaIri force between the terminal voltage V _A of the drive winding 3 1 drive winding 3 2 first voltage difference signal is these voltage differences _VBA is output. Second the Sado增width unit 6 2, drive卷線3 2 between the terminal voltage V _B and the terminal voltage V _c of the drive winding 3 3 is input, a second voltage difference is these voltage differences The signal V _CB is output. Third difference The dynamic amplifier 6 3, is the input terminal voltage V _C of the drive winding 3 3 and the terminal voltage V _A of the drive winding 3 1, the third voltage difference signal V _AC is these voltage difference is outputted You.

Reference numeral 64 denotes a first comparator which receives the first voltage difference signal V _BA and the second voltage difference signal V _CB and supplies a sensorless signal Z _A to the position feedback drive signal generator 51. _{Reference numeral 65} denotes a second comparator which inputs the second voltage difference signal V _CB and the third voltage difference signal V _AC and supplies a sensorless signal Z _B to the position feedback drive signal generator 51. 6 6 is a third comparator receives a third voltage difference signal V _AC and the first voltage difference signal V _BA, giving a sensorless signal Z _C to the position feedback drive signal generating unit 5 1.

Sensorless signal Z _A to Z _C becomes a pulse train signal as shown in FIG. 6, is these rising portions and falling portions of the represent zero cross Boyne City of induced voltage generated in the drive winding 3 1-3 3 I have. FIG. 6 shows the waveforms of the commutation control signals Au to CL output in response to the sensorless signals ZA to Zc. Returning to FIG. 4, the control unit 50 responds to the stop command signal SC output from the stop command signal generator 80, and outputs a signal from the plurality of predetermined ones of the switching transistors 42 to 44. Switching transistor or switching transistor 45 A stop control signal generator 5 that outputs a set of stop control signals SS for simultaneously turning on a plurality of switching transistors out of 5 to 47. Has eight. A set of stop control signals SS output from the stop control signal generator 58 is applied to the bases of the corresponding switching transistors 42 to 47 via the OR gates 52 to 57. . Note that the stop command signal SC is also input to the position feedback drive signal generator 51, and the position feedback drive signal generator 51 responds to the input of the stop command signal SC to generate commutation control signals A _{U to} C. It is configured to stop the output of _L.

In the present embodiment, the stop control signal generator 58 responds to the stop command signal SC and outputs a set of control signals for turning on the switching transistors 42, 43, and 44 simultaneously. It is configured to output as signal SS. As a result, the terminals of the A-phase winding 31, the B-phase winding 32, and the C-phase winding 33 are short-circuited, thereby providing a braking force to the rotation of the magnet rotor 34. It has become. In this case, since all of the switching transistors 45 to 47 are off, No current flows from the source B to the DC brushless motor 30 via the commutator circuit 41.

The set of stop control signals SS described above is an example, and the present invention is not limited to this configuration. Two of the group of switching transistors 42 to 44, for example, switching transistors Only 42, 4 and 3 may be turned on. A configuration may be adopted in which two or more of the other group of switching transistors 45 to 47 are simultaneously turned on. In this case, three of them may be turned on at the same time, or any two of them may be turned on at the same time. In addition, in each case, the selected switching transistors are completely turned on, and the switching transistors are turned on intermittently by cycling to limit the current flowing through the drive winding to a predetermined level or less. Thus, an excessive current may be prevented from flowing through the drive winding.

According to the configuration shown in FIG. 4, the output is stopped commutation control signal A _u -C _L from the position feedback driving signal generating unit 5 1 in response to an input of the stop command signal SC, alternatively 1 A set of stop control signals SS is output from the stop control signal generator 58, and the rotating drive windings 31, 32, and 33 of the DC brushless motor 30 are short-circuited. As a result, a magnetic field that suppresses the rotation of the magnet rotor 34 is generated by the current flowing through the drive windings 31, 32, and 33. Rotation can be prevented without the addition of special circuit elements. If the input / output pressure difference of the compression mechanism 10 is large, the compressor 1 overcomes the above-mentioned braking force of the DC brushless motor and rotates slightly in the reverse direction. This has the effect of reducing the difference and facilitating restart. Therefore, the check valve 23 employed in the compression mechanism 10 shown in FIG. 2 can be omitted. That is, when the check valve 23 is not provided, the pressure in the discharge chamber 21 increases due to the pressure generated in the discharge port 22 when the rotation of the DC brushless motor 30 is stopped, and the compressor 1 Although the reverse rotation is attempted, the reverse rotation can be effectively suppressed without the check valve 23 due to the rotation suppressing force of the magnet rotor 34 due to the short-circuit of the drive windings 31, 32, 33. As described above, an example of the embodiment of the present invention has been described. However, the control unit 50 may be configured using a microcomputer having a known hardware configuration.

FIG. 7 is a flowchart showing a control program of a microcomputer system configured to perform a function equivalent to the function of the control unit 50 shown in FIG. When the control is started, in step 71, the compressor 1 is operated at a rotation speed according to the air-conditioning load. This operation is performed by providing a sensor-less signal ZA from the position detecting circuit 6 0, Z _B, in response to Z _c in Community involvement Te Ichita circuit 4 1 a commutation control signals A u ~ C _L You. In step 72, it is determined whether or not the stop command signal SC has been input. If the stop command signal SC has not been input, the flow returns to step 71 to continue the operation of the compressor 1.

When the stop Sashiawase signal SC is inputted, the determination result Step 7 2 enters YES next scan Tetsupu 7 3, wherein one set of the control stop stops the output of the commutation control signals A _u -C _L A signal SS is output, and a predetermined switching transistor is turned on. Thereby, a braking force against the rotation of the magnet rotor 34 can be given. In step 74, it is determined whether a predetermined set time has elapsed after execution of step 73. This set time is set to a time necessary for the input / output pressure difference of the compressor 1 to become substantially zero after the stop command signal SC is input. If it is determined in step 74 that the set time has not elapsed, the determination result in step 74 becomes NO, and the flow waits for the set time to elapse. When the set time has elapsed, the determination result of step 74 is YES, and the process proceeds to step 75. In step 75, the switching transistors 42 to 47 are all turned off, and the operation stop of the compressor 1 is completed. Industrial applicability

As described above, the air conditioner drive control method and apparatus according to the present invention are useful for preventing reverse rotation of an air conditioner equipped with a compressor driven by a DC brushless motor when the operation is stopped. .

Claims

The scope of the claims

1. DC brushless motor comprising a magnet rotor and a set of drive windings; a compressor having a compression mechanism driven by the DC brushless motor; A first switching element group and a second switching element group for commutating a drive current from a DC power supply are provided, and each of the switching elements of the first and second switching element groups is set at a rotational position of the rotor. Circuit control means for driving the DC brushless motor to rotate by controlling ON / OFF in response to the ON / OFF control.

In response to a stop command signal to the DC brushless motor, on / off control of the switching element is stopped, and one of the first or second switching element group is simultaneously turned on. Thus, a drive control method for an air conditioner, wherein at least one of the one set of drive windings is brought into a short-circuit state.

2. The drive control method for an air conditioner according to claim 1, wherein the conduction state is a continuous conduction state.

3. The drive control method for an air conditioner according to claim 1, wherein the conduction state is an intermittent conduction state.

4. In a drive control device for an air conditioner including a compressor having a compression mechanism driven by a DC brushless motor including a magnet rotor and a set of drive windings,

DC power supply,

A first group of switching elements connected between one output of the DC power supply and the set of drive windings, and a first switching element group connected between the other output of the DC power supply and the set of drive windings; A commutation circuit including the second switching element group, A position detection circuit for detecting a rotational position of the magnet rotor,

The first and second switching means for commutating a drive current supplied from the DC power supply to the drive winding so that a rotational force is applied to the rotor in response to a detection result of the position detection circuit. Position feedback drive signal generating means for generating a commutation control signal for controlling on / off of each switching element of the element group;

Stopping control means for simultaneously controlling a plurality of one of the first and second switching element groups to a conductive state,

In response to a stop command signal to the DC brushless motor, the output of the commutation control signal from the position feedback drive signal generation means is stopped, and the plurality of switching elements are simultaneously controlled to be conductive by the stop control means. A drive control device for an air conditioner, characterized in that:

5. The drive control device for an air conditioner according to claim 4, wherein the conduction state is a continuous conduction state.

6. The drive control device for an air conditioner according to claim 4, wherein the conduction state is an intermittent conduction state.

7. The stop control means for outputting a set of stop control signals for controlling the ON / OFF state of each of the switching elements constituting the first and second switching element groups. The drive control device for an air conditioner according to any one of the preceding claims.

8. There is provided an orgate corresponding to each of the switching elements constituting the first and second switching element groups, and the commutation control signal and the stop control signal are transmitted through the corresponding orgate. The drive control device for an air conditioner according to claim 7, wherein the drive control device is configured to be supplied to a corresponding switching element.

9. The position detecting circuit is configured to generate a back electromotive force induced in each of the one set of drive windings. The drive control device for an air conditioner according to claim 4, wherein the rotational position of the magnet rotor is detected from pressure.