JPH1175386A - Permanent magnet motor and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brushless DC motor which does not need excessive wirings and terminals, has a simple construction, facilitates the size reduction and has a protective device. SOLUTION: A three-phase power is supplied from a motor driving circuit unit 33 to a motor unit 32 through power supply lines 34u, 34v and 34w, and the armature windings 35u, 35v and 35w of the motor unit 32 are successively excited to turn a rotor. Induced voltages which are induced in the armature windings 35u, 35v and 35w by the rotation of the rotor are detected to detect a rotor position. The current application phases of the armature windings 35u, 35v and 35w are switched in accordance with the detected result to drive the rotor to rotate continuously. Further, a protective device 43 which is made to operate by a temperature is inserted in series in the middle of the power supply line 34u and, when the induced voltage of the armature winding 35u is not detected by the opening operation of the protective device 43, the power supply to the motor unit 32 is discontinued. With this constitution, the simple construction and the size reduction can be realized easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet motor having a protection device and a control method therefor.

[0002]

2. Description of the Related Art Conventionally, a permanent magnet motor, for example, a brushless DC motor or a compressor such as an air conditioner which is a device equipped with the motor has a protection device for preventing overcurrent of the motor and overheating of the motor or the device. ing. A protection device for preventing overcurrent is generally provided in a motor drive circuit unit for controlling the driving of the motor unit of the brushless DC motor, and when the overcurrent is detected by the protection device, the motor is driven based on the detection result. The switching element is turned off to prevent overcurrent from flowing through the winding of the motor.

On the other hand, a device provided with a protection device for preventing an excessive rise in temperature is configured as follows. That is, FIG.
FIG. 1 is a circuit diagram of a conventional brushless DC motor provided with a protection device for preventing excessive temperature rise. In FIG. 6, a brushless DC motor 1 includes a motor unit 2 and a motor drive circuit unit 3. In the brushless DC motor 1, the single-phase AC supplied from the single-phase AC power supply 4 is DC-converted by a DC conversion circuit (not shown) of the motor drive circuit unit 3,
Further, the switching element 6 is controlled under the control of the drive control circuit 5.
, And is supplied to the motor unit 2 while sequentially switching the energized lines of the three power supply lines 7.

The motor section 2 is provided with a protection device 8 for preventing overheating, such as a temperature fuse or a bimetal type thermostat, for preventing overheating. The operation output of the overheating protection device 9 is provided. Is input to the drive control circuit 5 via the signal line 10. Then, when the protection device 8 detects an excessive temperature rise and performs an opening operation, the drive control circuit 5 causes the switching element unit 6 to open the OF device.
F, the rotation of the brushless DC motor 1 is stopped.

Further, in the above-described protection device for preventing overcurrent and protection device for preventing overheating, the output of the protection device is input to the motor drive circuit, and the operation of the switching element is controlled. And brushless DC
The motor has stopped rotating. In this case, the protection device may be inserted directly in the middle of one of the three power supply lines to directly cut off the current flowing through the power supply line in the event of an overcurrent or abnormal temperature rise. However, in a brushless DC motor which is operated by converting a direct current into a three-phase, there is a possibility that an open-phase operation is caused only by interrupting the current of one power supply line.

For this reason, when the protection device is inserted into the power supply line to interrupt the current, the following configuration is used. That is, FIG. 7 is a circuit diagram of a conventional brushless DC motor in which a protection device is inserted into a power supply line. In FIG. 7, the brushless DC motor 11 includes a motor unit 12 and a motor drive circuit unit 13. ing. In the brushless DC motor 11, the single-phase AC supplied from the single-phase AC power supply 4 is DC-converted by a DC conversion circuit (not shown) of the motor drive circuit unit 13, and further, the switching element is controlled under the control of a drive control circuit (not shown). , And is supplied to the motor unit 12 while sequentially switching the current-carrying lines of the three power supply lines 7.

The motor section 12 has an armature winding 14 which is arranged at a predetermined position on the fixed side and through which a current converted into three phases flows is connected in a star shape, and further has a neutral point and each armature winding. A protection device 15 for preventing overcurrent, for example, is inserted directly between the neutral point 14 and the neutral point 14 to simultaneously cut off the two. When the protection device 15 detects an overcurrent and performs an opening operation, the protection device 15 opens the star-connected armature windings 14 and the neutral point at the same time. Become a brushless DC motor 11
The rotation of is stopped. In addition, the protection device 1
In the case where the reference numeral 5 is for preventing an excessive temperature rise, when the temperature rise is detected and the opening operation is performed, the brushless D
The rotation of the C motor 11 stops.

Further, a compressor such as an air conditioner equipped with a conventional brushless DC motor will be described with reference to a side view of FIG. 8, a compressor 21 includes a compressor main body (not shown) in a case 22,
The motor unit 2 of the brushless DC motor 23 for driving this
And the rotating shaft 24 of the brushless DC motor 23 is directly connected to the driving shaft of the compressor main body. Also, the lead wire 2 derived from the armature winding 14 of the motor unit 2
5 is fixed to the power supply line 7 via a sealed terminal portion 26 fixed to the case 22. On the outer surface of the armature winding 14 of the motor section 2, an over-temperature protection device 9 of a protection device 8 for preventing over-heating is attached, and a lead wire 27 of the over-temperature protection device 9 is It is fixed to the signal line 10 via the sealed terminal portion 28.

With such a configuration, the single-phase AC supplied from the single-phase AC power supply 4 is DC-converted by a DC conversion circuit (not shown) of the motor drive circuit unit 3, and the drive control circuit 5 is also controlled. The three power supply lines 7 are converted to three phases by the switching element 6 and supplied to the motor unit 2 via the lead wire 25 while sequentially switching the energized lines of the three power supply lines 7. As a result, the motor unit 2 rotates under the predetermined control of the drive control circuit 5, and drives the compressor main body to execute the predetermined operation of the compressor 21. And
When the over-temperature protection device 9 detects an over-temperature rise and the protection device 8 is opened, the switching element 6 is turned off by the drive control circuit 5 and the rotation of the motor is stopped.

However, in the prior art as described above,
In the brushless DC motors 1 and 23 in which the protection device 8 is provided between the motor drive circuit unit 3 and the motor unit 2, for example, a component that detects an overcurrent on the circuit board of the drive control circuit 5 and limits or interrupts the current, A circuit, and a motor unit 2
And a signal line 10 of a protection device 8 in addition to the power supply line 7. Further, in a configuration in which a brushless DC motor 23 is used for the compressor 21 and the motor unit 2 is housed in the case 22, an electrical connection between the lead wire 25 of the armature winding 14 and the power supply line 7 is provided. It is necessary to provide a sealed terminal portion 26 for connecting the inside and the outside of the case 22.

From this point of view, the compressor 21 and the equipment such as the air conditioner on which the compressor 21 is mounted must be provided in a limited space, and the brushless DC motors 1, 23 themselves or the compressor 21 This makes it difficult to miniaturize the equipment on which it is mounted.

Further, in the case where the power supply line 7 is directly cut off, if a protection device 8 that cuts off only one of the three power supply lines 7 is used, the phase loss occurs. Abnormal operation. On the other hand, in order to avoid open-phase operation, the protection device 15 is directly inserted into the neutral point of each of the star-connected armature windings 14 of the motor unit 12 of the brushless DC motor 11 so that three armature windings are formed. When the protection devices 14 are simultaneously shut off, the protection device 15 becomes complicated, large, and expensive.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been developed in such a manner that at least one of the power supply lines to the motor section does not cause open-phase operation. Provided is a permanent magnet motor which has a protection device so as to shut off, eliminates the need for providing extra wiring and terminals for the protection device, has a simple structure, and is easily miniaturized, and a control method therefor. The purpose is to do.

[0014]

SUMMARY OF THE INVENTION A permanent magnet motor and a method of controlling the same according to the present invention supply power from a motor drive circuit section to an armature winding of a motor section via a power supply line, and sequentially rotate the armature winding. In a control method of a permanent magnet motor configured to rotate a rotor by excitation, a protection device for the motor unit is interposed in series at an intermediate portion of a power supply line, and the armature is opened by opening the protection device. When a drive signal of the winding is not detected, the method is characterized in that power supply to the motor unit is stopped,
A motor unit configured to sequentially excite the armature windings to rotate the rotor; a motor drive circuit unit for supplying power to the armature windings of the motor unit; Power supply line to supply power to the line,
The rotor position is detected by detecting an induced voltage induced in the armature winding due to the rotation of the rotor, and the energized phase of the armature winding is switched based on the rotor position detection result to continue the rotor. In addition to being configured to rotate, a protective device that operates by temperature is interposed in the middle of the power supply line in series, and the motor is activated when the protective device is opened and the induced voltage of the armature winding is not detected. A motor unit configured to turn off the rotor by sequentially exciting the armature windings, and an armature of the motor unit. A motor drive circuit for supplying power to the windings; and a power supply line for supplying power from the motor drive circuit to the armature windings, the induction being induced in the armature windings as the rotor rotates. The rotor position is detected by detecting the voltage, and the energizing phase of the armature winding is switched based on the rotor position detection result to continuously drive the rotor to rotate. And a means for stopping power supply to the motor unit when an induced voltage of the armature winding is not detected by opening the protection device in series. A motor section configured to sequentially excite armature windings to rotate the rotor, a motor drive circuit section for supplying power to the armature windings of the motor section, A power supply line for supplying power from the motor drive circuit to the armature winding is provided, and rotor position detection is performed by detecting an induced voltage induced in the armature winding as the rotor rotates. And thereby configured to switch the conduction phase of the armature winding is driven to rotate continuously the rotor on the basis of the rotor position detection result,
In the middle of the power supply line, a protection device that operates by both temperature and current is interposed in series, and if the induced voltage of the armature winding is not detected by opening the protection device, the power to the motor A motor unit configured to sequentially excite the armature windings to rotate the rotor, and to supply power to the armature windings of the motor unit. And a power supply line for supplying power from the motor drive circuit section to the armature winding, and obtains a current phase signal from the current flowing through each of the armature windings, and The voltage applied to the armature winding from the motor drive circuit unit based on the signal is controlled so as to have a predetermined phase with respect to the current flowing through the armature winding, and the rotor is continuously rotated and driven, Power supply A protection device that operates in accordance with temperature is interposed in series at an intermediate portion of the motor, and means for stopping power supply to the motor unit when a current phase signal is not detected from the armature winding by opening the protection device. A motor unit configured to sequentially excite armature windings to rotate a rotor, and a motor drive circuit for supplying electric power to the armature windings of the motor unit And a power supply line for supplying power from the motor drive circuit to the armature winding, and obtains a current phase signal from the current flowing through each of the armature windings, and drives the motor based on the current phase signal. The voltage applied to the armature winding from the circuit unit is controlled so as to have a predetermined phase with respect to the current flowing through the armature winding, and the rotor is continuously rotated and driven. Ni And a means for stopping power supply to the motor unit when the current phase signal is not detected from the armature winding due to the opening operation of the protection device. A motor unit configured to rotate the rotor by sequentially exciting the armature windings,
A motor drive circuit section for supplying power to the armature winding of the motor section; and a power supply line for supplying power to the armature winding from the motor drive circuit section. A current phase signal is obtained, and the voltage applied to the armature winding from the motor drive circuit section is controlled based on the current phase signal so that the voltage applied to the armature winding has a predetermined phase with respect to the current flowing through the armature winding. In addition, a protective device that operates by both temperature and current is interposed in the middle part of the power supply line in series, and the protective device is opened to operate, and the current phase from the armature winding is increased. It is characterized by comprising means for stopping the power supply to the motor unit when the signal is not detected, further,
The motor unit drives the compressor, and the protection device is attached to the armature winding of the motor unit, and operates according to the temperature of the armature winding. Wherein the motor unit drives the compressor, the protection device is provided inside the compressor case, and operates according to the internal temperature of the compressor case. Drives the compressor, the protection device is provided in the compressor case, and operates according to the temperature of the compressor case.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

First, an embodiment of a brushless DC motor which is a first embodiment of the permanent magnet motor will be described with reference to FIG. FIG. 1 is a circuit diagram. In FIG. 1, a brushless DC motor 31 includes a motor unit 32, a motor drive circuit unit 33 for driving and controlling the motor unit 32, and a motor connected to the motor drive circuit unit 33 and the motor unit 32. It comprises three power supply lines 34u, 34v, 34w for supplying power to the section 32. The motor unit 32 includes armature windings 35u, 35v, and 35w mounted at predetermined positions on a fixed side (not shown), and armature windings 35u, 35w.
A rotor (not shown) that is rotated and driven by sequentially energizing and exciting v and 35w at predetermined timings is provided.

The motor drive circuit section 33 includes a DC conversion circuit 37 for converting single-phase AC supplied from a single-phase AC power supply 36 to DC, and a DC output from the DC conversion circuit 37 by switching operation. A switching element 38 that converts the phase into power and outputs it to the motor unit 32 through the power supply lines 34u, 34v, and 34w, and a drive control circuit 39 that outputs a drive signal to cause the switching element 38 to perform a predetermined switching operation based on an operation command. And the intermediate portions 40u, 40v, of the power supply lines 34u, 34v, 34w.
An input side is connected to 40w, and a position detection circuit 41 for outputting a position signal of the rotor to the drive control circuit 39 from a voltage induced in the armature windings 35u, 35v, 35w by rotation of the rotor is provided.

Further, three power supply lines 34u, 34v,
An intermediate portion 40u to which one input side of the position detection circuit 41 is connected is connected to one power supply line 34u of the 34w.
Between the corresponding connection terminal 42u of the connection terminals 42u, 42v, 42w of the motor section 32, a protection device 43, which is an overcurrent prevention device such as a current fuse or an overcurrent limiter, is inserted in series. .

And, with the above-mentioned structure,
Normally, a single-phase AC is supplied from the single-phase AC power supply 36 to the DC conversion circuit 3.
7 and is converted to DC by a DC conversion circuit 37.
The DC output from the DC conversion circuit 37 is converted into three phases by the switching operation of the switching element 38 based on the drive signal of the drive control circuit 39 based on the operation command, and is sequentially converted to three phases, thereby sequentially changing the power supply lines 34u, 34v, and 34w. It flows and is output to the armature windings 35u, 35v, 35w of the motor unit 32. The three-phase current is applied to the armature winding 35 of each phase.
u, 35v, and 35w are sequentially excited by flowing at predetermined timing, and the rotor rotates at a predetermined speed.
As the rotor rotates, the armature windings 35u, 35 of each phase
A voltage corresponding to the rotational position of the rotor is induced in the armature windings 35u, 35v, 35w.
Each power supply line 34u, 34v, 34 connected to 35w
Join w.

The position detecting circuit 41 includes intermediate portions 40u, 40v, 4 of the power supply lines 34u, 34v, 34w.
A voltage from 0 w is input. A detection process is performed on the input voltage by the position detection circuit 41, and a voltage corresponding to the voltage induced in the armature windings 35u, 35v, and 35w with the rotation of the rotor is obtained. A rotor position signal is formed on the basis of the signal, and the rotor position signal is output to the drive control circuit 39. In the drive control circuit 39 to which the rotor position signal is input, the rotation status of the motor unit 32 is compared with the operation command by the rotor position signal,
The drive signal is output to the switching element 38 again. By repeating the above process, the brushless DC motor 31
Continue rotation under predetermined operating conditions.

The rotating brushless DC motor 31
When an abnormal current occurs and an overcurrent flows, the protection device 43 is activated and the protection device 43 is opened, and the power supply line 34u in which the protection device 43 is inserted in series is Connection terminal 4 between portion 40u and motor portion 32
2u is disconnected. As a result, a voltage corresponding to the voltage induced in the armature winding 35u due to the rotation of the rotor cannot be obtained from the power supply line 34u in the position detection circuit 41. As a result, only the rotor position signal corresponding to the voltage induced in the armature winding 35u is no longer input from the position detection circuit 41 to the drive control circuit 39, and the switching element is switched by the drive control circuit 39 according to a preset program. 38 switching operation is OF
F, the power supply to the motor unit 32 is cut off, and the rotation of the brushless DC motor 31 stops.

As described above, the brushless DC motor 31
Is performed by obtaining the position signal of the rotor from the voltage induced in the armature windings 35u, 35v, and 35w in accordance with the rotation of the rotor, the position of the rotor is detected.
3 includes at least one of three power supply lines 34u, 34v, and 34w for supplying power from the switching element 38 to the motor unit 32, for example, an intermediate portion 40u of the power supply line 34u that is electrically connected to the armature winding 35u; If an overcurrent flows to the protection device 43 due to an abnormality and the device is opened just by inserting it in series between the connection terminal 42u of the motor portion 32 and the rotor, the position signal of the rotor cannot be obtained only from the power supply line 34u. The operation of the switching element 38 can be turned off, and the rotation of the brushless DC motor 31 can be stopped. Thus, there is no need to provide additional wiring and terminals for the protection device 43, and the configuration becomes simple. Can be reduced in size and cost can be reduced, and there is no risk of abnormal operation due to phase loss.

Next, an embodiment of a permanent magnet synchronous motor which is a second embodiment of the permanent magnet motor will be described with reference to FIG. FIG. 2 is a circuit diagram. In FIG. 2, a permanent magnet type synchronous motor 71 includes a motor unit 72, a motor drive circuit unit 73 for driving and controlling the motor unit 72, and the motor drive circuit unit 73 and the motor unit 72 are connected. And three power supply lines 74u, 74v, 74w for supplying power to the motor unit 72. The motor unit 72 includes armature windings 75u, 75v, and 75w mounted at predetermined positions on the fixed side (not shown), and armature windings 75u, 75w.
A rotor (not shown) in which rotor poles of permanent magnets that rotate sequentially in synchronization with the frequency of the motor drive circuit section 73 by sequentially energizing and exciting v and 75w at predetermined timings, respectively, is provided. .

The motor drive circuit 73 includes a DC conversion circuit 37 for converting single-phase AC supplied from a single-phase AC power supply 36 to DC, and a DC output from the DC conversion circuit 37 by a switching operation. A switching element 76 that converts the frequency into three phases and outputs the three-phase power to the motor unit 72 through the power supply lines 74u, 74v, and 74w, and a drive that outputs a drive signal to cause the switching element 76 to perform a predetermined switching operation based on an operation command. Control circuit 77
The outputs of the current detectors 78u, 78v, 78w inserted in the intermediate portions of the power supply lines 74u, 74v, 74w are connected to the inputs, and the respective winding currents flowing through the armature windings 75u, 75v, 75w are detected. , A current phase detection circuit 79 that outputs a current phase signal to the drive control circuit 77 based on the current detection signal
And are provided.

Also, three power supply lines 74u, 74v,
One of the power supply lines 74u among the power supply lines 74w is connected to the insertion portion of the current detector 78u and the connection terminals 80u,
A protection device 43 such as a current fuse or an overcurrent limiter such as an overcurrent limiter is inserted in series between the corresponding connection terminal 80u of 80v and 80w.

And, with such a configuration,
Normally, a single-phase AC is supplied from the single-phase AC power supply 36 to the DC conversion circuit 3.
7 and is converted to DC by a DC conversion circuit 37.
Then, the DC output from the DC conversion circuit 37 is converted into three phases of a predetermined frequency by the switching operation of the switching element 76 according to the drive signal of the drive control circuit 77 based on the operation command, and is sequentially converted to the power supply lines 74u and 74v. , 7
4w, the armature windings 75u, 75 of the motor section 72.
v, 75w. A three-phase current of a predetermined frequency flows through the armature windings 75u, 75v, 75w of each phase at a predetermined timing, and is sequentially excited, and the rotor is synchronized with the frequency of the current flowing through the armature windings 75u, 75v, 75w. To rotate at a predetermined speed. The rotation speed of the rotor is controlled by the drive control circuit 77 to the armature windings 75u, 75u.
v, 75w by changing the frequency of the current flowing therethrough.

The power supply lines 74u, 74v, 74w
Current detectors 78u, 78v, 78 inserted in the middle of
The current flowing through the armature windings 75u, 75v, and 75w is detected by w.
Is input to Then, detection processing is performed by the current phase detection circuit 79, and a corresponding current phase signal is output to the drive control circuit 77 based on the current detection signals of the current detectors 78u, 78v, 78w. Further, in the drive control circuit 77, the armature windings 75u, 75v,
Processing for controlling the drive voltage applied to 75w to have a predetermined phase is performed, a drive signal is output to the switching element 76, and the control is executed.

The rotating permanent magnet synchronous motor 71
Causes an overcurrent to flow, and the protection device 43 is activated in accordance with this. When the protection device 43 is opened, the power supply line 74u in which the protection device 43 is inserted in series A disconnection occurs between the detector 78u and the connection terminal 80u of the motor unit 72. As a result, a current detection signal from the current detector 78u cannot be obtained. That is, only the current phase signal corresponding to the current flowing through the armature winding 75u is output from the current phase detection circuit 79 to the drive control circuit 77.
Is not inputted to the switching element 7 by the drive control circuit 77 according to a preset program.
6 is turned off, the power supply to the motor unit 72 is cut off, and the rotation of the permanent magnet synchronous motor 71 stops.

As described above, the permanent magnet synchronous motor 71
Rotation obtains a current phase signal from the current flowing through the armature windings 75u, 75v, 75w, and based on this, the drive voltage applied to each armature winding 75u, 75v, 75w has a predetermined phase. In the control operation, the protection device 43 is connected to at least one of the three power supply lines 74u, 74v, and 74w that supply power from the switching element 76 to the motor unit 72, for example, the armature winding 75u. Current detector 78u inserted in the middle of power supply line 74u
When the overcurrent flows to the protection device 43 due to the occurrence of an abnormality and is opened by simply inserting it in series between the motor unit 72 and the connection terminal 80u of the motor unit 72, the armature winding 75u flows only from the power supply line 74u. The current detection signal of the current cannot be obtained, the operation of the switching element 76 is turned off, the rotation of the permanent magnet synchronous motor 71 can be stopped, and additional wiring and terminals for the protection device 43 need to be additionally provided. The permanent magnet type synchronous motor 71 itself can be reduced in size and cost, and there is no risk of abnormal operation due to phase loss.

In the first and second embodiments described above, the protection device 43 has been described as being constituted by an overcurrent preventer such as a current fuse or an overcurrent limiter. However, the present invention is not limited to this. Rather than an over-temperature protector such as a thermal fuse or bimetal thermostat,
Further, the protection operation may be performed by detecting at least an excessive temperature rise or an abnormality of the overcurrent by the interaction between the temperature and the current in which both are combined.

Next, a compressor which is an embodiment of a device equipped with a brushless DC motor will be described with reference to FIGS. FIG. 3 is a side view showing a main part in partial cross section, FIG. 4 is a side view showing a main part of the first modification in partial cross section, and FIG. 5 is a side view showing a main part of the second modification. It is a side view which shows a part as a partial cross section. In addition, the first of the above permanent magnet motors
The same parts as those of the embodiment of the brushless DC motor according to the embodiment are denoted by the same reference numerals, and the description thereof will be omitted. A different configuration of the present invention will be described.

3 to 5, in a compressor 51 such as an air conditioner equipped with a brushless DC motor, a lower case 52 and an upper case 53, which are closed on one side and open on the other side, are hermetically sealed with each other. A compressor body (not shown) and a brushless DC motor 5 for driving the compressor are provided in a case 54 formed into an upright cylindrical shape with both ends closed.
5 is hermetically housed, and a rotating shaft 57 of a rotor 56 of the brushless DC motor 55 is directly connected to a drive shaft of the compressor body. A sealed terminal portion 60 is attached to an upper surface portion of the upper case portion 53 of the case 54 so that an inner terminal 58 is provided inside the case 54 and an outer terminal 59 is provided outside the case 54. A protection device 61 for preventing overheating, such as an overheating prevention device such as a thermal fuse or a bimetal thermostat, is attached to the upper and outer surfaces of the portion 53 so as to detect the temperature of the case 54.

On the other hand, a three-phase armature winding 35 is mounted on the stator 62 of the motor section 32. Further, lead wires 63u, 63v, 6 of each phase derived from the armature winding 35 are provided.
3 w is fixed to the inner terminal 58 of the sealed terminal portion 60 whose tip is fixed to the case 54. On the other hand, three power supply lines 34u,
One ends of 34v and 34w are fixed. The other ends of the power supply lines 34u, 34v, and 34w are fixed to corresponding predetermined terminals of the switching element 38 of the motor drive circuit unit 33. A protection device 61 fixed to the outer surface is inserted in series.

The motor drive circuit section 33 includes a single-phase AC power supply 3 similarly to the above-described embodiment of the brushless DC motor.
A DC conversion circuit 37 for converting the single-phase AC supplied from the DC conversion circuit 6 into a DC, and converting the DC output from the DC conversion circuit 37 into a three-phase by a switching operation to convert each power supply line 3
4u, 34v, 34w, a switching element 38 for outputting to the motor section 32, a drive control circuit 39 for outputting a drive signal for causing the switching element 38 to perform a predetermined switching operation based on an operation command, and a power supply line 34.
The input side is connected to an intermediate portion between u, 34v, and 34w, and a position detection circuit 41 that outputs a position signal of the rotor 56 to the drive control circuit 39 from voltages induced in each phase of the armature winding 35 by rotation of the rotor 56. It is comprised including.

In such a configuration, the single-phase alternating current is usually converted to direct current by the motor drive circuit section 33,
The direct current is converted into three phases by the switching operation of the switching element 38 by the drive signal of the drive control circuit 39 based on the operation command, and is sequentially converted into the three-phase power supply lines 34u, 34v, 3
4w, and is output to each corresponding phase of the armature winding 35 of the motor unit 32. Then, current flows through each phase of the armature winding 35 at a predetermined timing to be sequentially excited, and the rotor 56 rotates at a predetermined speed. With the rotation of the rotor 56, a voltage corresponding to the rotational position of the rotor 56 is induced in each phase of the armature winding 35, and the induced voltage is
5, each power supply line 34u, 34v, 3 connected to each phase
Join 4w.

In the position detection circuit 41 of the motor drive circuit section 33, the voltage at the intermediate portion of the power supply lines 34u, 34v, 34w is input, and the input voltage is subjected to a detection process to obtain the obtained voltage. The position signal of the rotor 56 is formed on the basis of the above, and the position signal of the rotor 56 is output to the drive control circuit 39. In the drive control circuit 39, the rotor 5
The rotation status of the motor unit 32 is compared with the operation command by the position signal of No. 6, and the drive signal is output to the switching element 38 again. And by repeating the above process, brushless D
The C motor 55 continues to rotate under a predetermined operating condition, and the compressor 51 continues a predetermined operation.

Further, when the compressor 51 is in an overload state during operation,
Alternatively, if the temperature of the case 54 rises abnormally due to a situation such as a shortage of the refrigerant gas and the like, the protection device 61 is actuated by detecting the excessive temperature, and when the protection device 61 is opened, the protection device 61 is opened. The power supply line 34u inserted in series is disconnected. As a result, the position signal of the rotor 56 obtained by the voltage induced in each phase of the armature winding 35 with the rotation of the rotor 56 cannot be obtained on the power supply line 34u in which the protection device 61 is inserted. As a result, of the position signal of the rotor 56 corresponding to the voltage induced in the armature winding 35, only one phase is not input to the drive control circuit 39 from the position detection circuit 41 of the motor drive circuit unit 33, The switching operation of the switching element 38 is turned off by the drive control circuit 39 according to a preset program, the power supply to the motor unit 32 is cut off, the rotation of the brushless DC motor 55 is stopped, and the operation of the compressor 51 is stopped. I do.

As described above, the rotation of the brushless DC motor 55 for driving the compressor body detects the position of the rotor 56 from the voltage induced in each phase of the armature winding 35 with the rotation of the rotor 56. In the compressor 51 which is performed by obtaining the position signal, the protection device 61 is connected to three power supply lines 34u, 34v, and 34w for supplying power to the motor unit 32.
By simply inserting at least one of them in series, for example, in the middle of the power supply line 34u, the temperature of the case 54 abnormally rises due to an overload condition of the compressor 51 or occurrence of an abnormality such as a shortage of refrigerant gas. When the protection device 61 is activated and opened, the position signal of the rotor 56 cannot be obtained only from the power supply line 34u, the operation of the switching element of the motor drive circuit unit 33 is turned off, and the brushless DC motor 5
5 can be stopped, and the operation of the compressor 51 can be stopped.

Thus, there is no need to provide additional wiring and terminals for the protection device 61, and the configuration is simple, and the compressor 51 can be reduced in size and cost.
In addition, since the number of wires around the compressor 51 that becomes high in temperature is reduced, the possibility of occurrence of troubles such as burnout of the wires is reduced.
Further, there is no possibility that the brushless DC motor 55 will be abnormally operated due to the phase loss.

In the above embodiment, the protection device 61 is used.
Is fixed to the upper outer surface of the upper case portion 53 of the case 54 and inserted in series at the intermediate portion of the power supply line 34u. However, as in the compressor 51a of the first modified example shown in FIG. Lead wires 63u, 63 of each phase derived from winding 35
v, 63w, for example, may be inserted in series in the middle of the lead wire 63u and provided so as to be located in the space in the case 54, and the ambient temperature in the case 54 may be detected. By doing so, the abnormality detection sensitivity is further improved, and the same operation and effect as in the above-described embodiment can be obtained.

Further, as in a compressor 51b of a second modification shown in FIG.
v, 63w, for example, may be inserted in series in the middle of the lead wire 63w, and may be arranged at the coil end of the armature winding 35 to detect the temperature of the armature winding 35. With such a configuration, the abnormality detection sensitivity is further improved, particularly the detection sensitivity of the armature winding 35 is further improved, and the same operation and effect as those of the above-described embodiment can be obtained.

Further, in the above-described embodiment, the protection device 61 is a device for preventing overheating such as a temperature fuse or an overheating prevention device formed of a bimetal thermostat. However, the present invention is not limited to this. An overcurrent prevention device such as a fuse or an overcurrent limiter, or a device that performs a protection operation by detecting at least a temperature rise or an abnormality of an overcurrent by interaction of temperature and current in which both are combined may be used.

[0043]

As is apparent from the above description, according to the present invention, the protection device can be disposed with a simple configuration without using extra wires or terminals while avoiding abnormal operation due to phase loss. This brings about effects such as downsizing and cost reduction.

[Brief description of the drawings]

FIG. 1 is a brushless DC according to a first embodiment of the present invention;
It is a circuit diagram of a motor.

FIG. 2 is a circuit diagram of a permanent magnet synchronous motor according to a second embodiment of the present invention.

FIG. 3 is a brushless DC according to the first embodiment of the present invention;
It is a side view which shows the principal part of the compressor in which the motor was mounted in partial cross section.

FIG. 4 is a brushless DC according to the first embodiment of the present invention;
It is a side view which shows the principal part of the 1st modification of the compressor in which the motor was mounted in partial cross section.

FIG. 5 is a brushless DC according to the first embodiment of the present invention;
It is a side view which shows the principal part of the 2nd modification of the compressor in which the motor was mounted in partial cross section.

FIG. 6 is a circuit diagram of a conventional brushless DC motor provided with a protection device for preventing excessive temperature rise.

FIG. 7 is a circuit diagram of a brushless DC motor in which a protection device is inserted into a conventional power supply line.

FIG. 8 is a side view showing a main part of a compressor equipped with a conventional brushless DC motor in a partial cross section.

[Explanation of symbols]

32, 72 ... Motor part 33, 73 ... Motor drive circuit part 34u, 34v, 34w, 74u, 74v, 74w ... Power supply line 35, 35u, 35v, 35w, 75u, 75v, 75
w armature winding 38, 76 switching element 39, 77 drive control circuit 41 position detection circuit 43, 61 protection device 51, 51a, 51b compressor 54 case 56 rotor 63u, 63v, 63w Lead wires 78u, 78v, 78w ... current detector 79 ... current phase detection circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02P 7/63 303 H02P 7/63 303V

Claims (10)

[Claims] The present invention relates to a permanent magnet motor configured to supply power from a motor drive circuit section to an armature winding of a motor section via a power supply line and to sequentially excite the armature winding to rotate a rotor. In the control method, when a protection device of the motor unit is interposed in series at an intermediate portion of the power supply line and a drive signal of the armature winding is not detected by opening the protection device, the motor A method for controlling a permanent magnet motor, wherein power supply to a unit is stopped. 2. A motor unit configured to sequentially excite armature windings to rotate a rotor, a motor drive circuit unit for supplying power to the armature windings of the motor unit, and a motor drive circuit unit A power supply line for supplying power to the armature winding from the rotor, detecting the rotor position by detecting an induced voltage induced in the armature winding due to the rotation of the rotor, and detecting the rotor position. While switching the energized phase of the armature winding based on the result, the rotor is configured to be continuously driven to rotate, and a protection device that operates according to temperature is provided in series at an intermediate portion of the power supply line, The permanent magnet motor further comprises means for stopping power supply to the motor unit when the induced voltage of the armature winding is not detected by opening the protection device. Ta. 3. A motor unit configured to sequentially excite armature windings to rotate a rotor, a motor drive circuit unit for supplying power to the armature windings of the motor unit, and a motor drive circuit unit A power supply line for supplying power to the armature winding from the rotor, detecting the rotor position by detecting an induced voltage induced in the armature winding due to the rotation of the rotor, and detecting the rotor position. While switching the current-carrying phase of the armature winding based on the result, the rotor is configured to be continuously driven to rotate, and a protection device that operates by current is provided in series at an intermediate portion of the power supply line, and The permanent magnet motor further comprises means for stopping power supply to the motor unit when the induced voltage of the armature winding is not detected by opening the protection device. Ta. 4. A motor unit configured to sequentially excite armature windings to rotate a rotor, a motor drive circuit unit for supplying power to the armature windings of the motor unit, and a motor drive circuit unit A power supply line for supplying power to the armature winding from the rotor, detecting the rotor position by detecting an induced voltage induced in the armature winding due to the rotation of the rotor, and detecting the rotor position. Based on the result, the armature winding is switched so as to continuously rotate and drive the rotor by switching the energized phase, and a protection device that operates by both temperature and current is serially connected to an intermediate portion of the power supply line. And interposing, further comprising means for stopping power supply to the motor unit when the induced voltage of the armature winding is not detected by the opening operation of the protection device. Permanent magnet motor. 5. A motor unit configured to sequentially excite armature windings to rotate a rotor, a motor drive circuit unit for supplying power to the armature windings of the motor unit, and a motor drive circuit unit A power supply line for supplying power to the armature winding from the motor, obtains a current phase signal from currents flowing through the armature winding, and outputs the electric motor from the motor drive circuit unit based on the current phase signal. The voltage applied to the armature winding is controlled so as to have a predetermined phase with respect to the current flowing through the armature winding, and the rotor is continuously driven to rotate. And a means for stopping power supply to the motor unit when a current phase signal is not detected from the armature winding by opening the protection device by operating the protection device in series. A permanent magnet motor. 6. A motor unit configured to sequentially excite armature windings to rotate a rotor, a motor drive circuit unit for supplying power to the armature windings of the motor unit, and a motor drive circuit unit A power supply line for supplying power to the armature winding from the motor, obtains a current phase signal from currents flowing through the armature winding, and outputs the electric motor from the motor drive circuit unit based on the current phase signal. The voltage applied to the armature winding is controlled so as to have a predetermined phase with respect to the current flowing through the armature winding, and the rotor is continuously driven to rotate, and the current is supplied to an intermediate portion of the power supply line. And a means for stopping power supply to the motor unit when a current phase signal is not detected from the armature winding by opening the protection device by operating the protection device in series. A permanent magnet motor. 7. A motor unit configured to sequentially excite armature windings to rotate a rotor, a motor drive circuit unit for supplying power to the armature windings of the motor unit, and a motor drive circuit unit A power supply line for supplying power to the armature winding from the motor, obtains a current phase signal from currents flowing through the armature winding, and outputs the electric motor from the motor drive circuit unit based on the current phase signal. The voltage applied to the armature winding is controlled so as to have a predetermined phase with respect to the current flowing through the armature winding, and the rotor is continuously driven to rotate. And a protection device that operates by both the current and the current is interposed in series, and when the current phase signal is not detected from the armature winding by opening the protection device, the power supply to the motor unit is stopped. A permanent magnet motor comprising means. 8. A motor unit for driving a compressor, wherein the protection device is attached to an armature winding of the motor unit and operates according to a temperature of the armature winding. Claim 2, Claim 4, Claim 5, Claim 7
A permanent magnet motor according to any one of the above. 9. The compressor according to claim 2, wherein the motor unit drives the compressor, and the protection device is provided inside the compressor case, and operates according to the internal temperature of the compressor case. The permanent magnet motor according to any one of claims 4, 5, and 7. 10. The compressor according to claim 2, wherein the motor unit drives the compressor, the protection device is provided in the compressor case, and operates according to the temperature of the compressor case. The permanent magnet motor according to any one of claims 4, 5 and 7.