KR100548843B1 - A method for controlling dc brushless motor - Google Patents

Abstract

After the motor has run stably, the Hall element inputs on each UVW phase are measured and the edge with the smallest error in the edge timing of the input signal is determined as the timing point. Then, the average value TGT_CCT of the edge interval between the current timing point and the previous timing point is obtained, and from the current timing point to the next timing point, it is assumed that the edge is detected in the time interval of TGT_CCT, and from each edge detection timing After T _OFF (= TGT_CCT × 4/16), turn off the waveform of the energization control signal, and turn on the waveform of the energization control signal after T _ON (= TGT_CCT × 10/16). Thereby, the fluctuation | variation of the electricity supply space to each winding can be made small.

Brushless Motor, Air Conditioner, Fan Motor, Hall Element, Position Detector

Description

Control method of DC brushless motor {A METHOD FOR CONTROLLING DC BRUSHLESS MOTOR}

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram of the air conditioner of embodiment of this invention.

2 is a schematic diagram showing a refrigeration cycle of an air conditioner.

3 is a schematic configuration diagram of a fan motor composed of a DC brushless motor.

4 shows waveforms of detection signals of respective Hall elements;

5 is a flowchart showing a control routine of an embodiment of the invention.

6 is a flowchart showing a processing routine of a determination process of a timing point.

7 is a flowchart showing a processing routine for synchronous operation.

8 is an explanatory diagram of edge intervals at hall element inputs.

9 is an explanatory diagram of synchronous operation when a timing point is determined at on timing of a Hall element input on a U phase;

10 is an explanatory diagram of timings for turning on and off an energization control signal in synchronous driving;

11 is an explanatory diagram of timings for turning on and off an energization control signal during normal operation;

<Explanation of symbols for the main parts of the drawings>

10: air conditioner

50: fan motor

60: control unit

62: rotor

64U, 64V, 64W: Hall Device

66U, 66V, 66W: winding

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method of a DC brushless motor, and more particularly, to a plurality of coil windings in a DC brushless motor employed in a fan motor mounted on an indoor unit or an outdoor unit of an air conditioner (hereinafter referred to as an air conditioner). The present invention relates to a control method of a direct current brushless motor for switching current.

Background Art Conventionally, a DC brushless motor has been widely used as a fan motor mounted on an indoor unit or an outdoor unit of an air conditioner or a motor of various other electric devices.

In this DC brushless motor, the position of a rotor including a permanent magnet is detected by a plurality of position detectors (hole elements, etc.) arranged at equal intervals in the vicinity of the rotational track of the rotor, and the detection signal is turned on and off. The rotor is rotationally driven by switching the energization to the coil windings for plural rotational driving based on the timing.

In general, energization to the coil windings is switched in synchronization with the detection signal on / off or at predetermined time intervals.

 However, the rotor rotates constantly due to misalignment of the bonding position of the permanent magnet with the rotor, variation of the magnetization of the permanent magnet, etc., misalignment of the position detector arrangement, variation of the operating characteristics of the position detector, and the like. Even if it rotates by the number, the on-off timing of the detection signal output from a position detector may not become equally spaced, and a change may arise.

In this way, if the on / off timing of the detection signal is not equally spaced and fluctuates in the interval, the energization timing to the coil winding is shifted from the normal timing, and the rotational torque is changed in the DC brushless motor, causing vibration and noise. There exists a possibility that the problem that this may occur may arise.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a control method of a direct current brushless motor capable of making small variations in the energization interval to the coil windings.

In order to achieve the above object, in the control method of the DC brushless motor according to claim 1, detection signals from a plurality of position detectors that detect the position of the rotor are turned on from off to off or from off during one rotation of the rotor. It is characterized by setting any one of the switching timings to switch to as a reference timing, and setting the electricity supply switching timing to a some coil winding based only on the set reference timing.

In addition, according to the control method of the DC brushless motor according to claim 2, the detection signal from the plurality of position detectors that detect the position of the rotor is switched from on to off or off to on while the rotor is rotated once. Set any one of the timings as the reference timing, calculate an average value of the intervals of the switching timings between the reference timing in the previous one revolution of the rotor and the reference timing in the first revolution of the rotor, and the next time from the current reference timing. It is characterized by switching the energization to the plurality of coil windings based on the timing of the calculated average value interval until the reference timing.

In addition, as a control method of the DC brushless motor of Claim 3, the control method of the DC brushless motor of Claim 1 or 2 WHEREIN: Based on the switching timing with the smallest fluctuation | variation of the relative time interval with respect to the switching timing before and behind. It is characterized by setting as timing.

Moreover, as a control method of the DC brushless motor of Claim 4, in the control method of the DC brushless motor of any one of Claims 1-3, execution start timing sets the difference of the real rotation speed and the target rotation speed to a predetermined value. It is characterized by the time when a DC brushless motor rotated continuously for more than predetermined time below.

In the DC brushless motor control method according to claim 1, detection signals from a plurality of position detectors that detect the position of the rotor are turned from on to off or on to off during one rotation of the rotor (for one cycle). Any of the switching timings for switching is set as the reference timing. Then, the energization switching timing to the plurality of coil windings is set based only on the set reference timing. For example, the average value of the interval of switching timing is calculated | required based on the interval of reference timing, and the timing of the average value interval is set as an electricity supply switching timing.

Conventionally, since the energization switching timing to a plurality of coil windings has been set on the basis of the switching timing of each time, the energization interval to the coil winding has fluctuated due to the variation of the switching timing of each time. By setting the energization switching timing up to one cycle or a plurality of cycles on the basis of the reference timing only, for example, the change in the switching timing of each time is prevented from affecting the energization interval to the coil windings, and thus the energization interval. The fluctuation of can be made small. As a result, problems such as fluctuations in rotation torque, vibration, and noise can be prevented.

Next, in the control method of the DC brushless motor of Claim 2, first, any one of the switching timing which switches the detection signal from the several position detector which detects the position of a rotor from ON to OFF or OFF to ON is performed. It is set as the reference timing.

Then, the average value of the intervals of the switching timings between the reference timing in the previous one revolution of the rotor and the reference timing in this one revolution is calculated.

Moreover, the electricity supply to a plurality of coil windings is switched based on the timing of the calculated average value interval from the current reference timing to the next reference timing. In other words, the detection signal from the position detector is regarded as being switched from on to off or off to on at the calculated average value interval from the current reference timing to the next reference timing. After 4 × 16), energization to the coil windings is stopped, and after (average value × 10/16), energization to the coil windings is started.

In this way, the average value of the interval of the switching timing between the previous reference timing and the current reference timing is calculated, and the detection signal of the position detector is regarded as being switched from on to off or off to on at the average interval, and based on the switching timing. By switching the energization to the plurality of coil windings, the fluctuations in the energization interval to the coil winding can be reduced, which can prevent problems such as rotational torque fluctuations, vibrations, and joints.

In addition, in the setting of the reference timing in the invention according to claim 1 or 2, any one switching timing may be set as the reference timing, but as described in claim 3, the variation of the time interval relative to the switching timing before and after It is preferable to set this smallest switching timing as the reference timing.

By setting the switching timing with the smallest variation in the relative time interval as the reference timing, it is possible to prevent the average value of the interval of switching timing between the calculated reference timings from fluctuating at each calculation. The fluctuations in the energization intervals between the coil windings of the cycles can be reduced.

Further, after the DC brushless motor starts to rotate stably, the shift of the bonding position of the permanent magnet or the like to the rotor described above, the shift of the magnetization of the permanent magnet, etc., the shift of the attachment position of the position detector, the position of the position detector Variation in the on-off timing interval of the position detection signal peculiar to the DC brushless motor, which is caused only due to a change in operating characteristics, or the like, starts to occur.

For this reason, the execution start timing of the control based on the control method of the DC brushless motor as described above is, as described in claim 4, the direct current is continuously performed for a predetermined time or more as the difference between the actual rotation speed and the target rotation speed is equal to or less than a predetermined value. It is preferable to set it as the point in time where the brushless motor rotates (the point in time when the brushless motor starts to rotate stably).

Moreover, as said position detector, the hall element mentioned later, an optical sensor (photodiode, a photo coupler, etc.), a magnetoresistive element, etc. can be employ | adopted.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

[Configuration of Air Conditioner]

1 and 2 show an air conditioner (hereinafter referred to as "air conditioner 10") applied to the present embodiment.

As shown in FIG. 1, the air conditioner 10 is constituted by an indoor unit 12 and an outdoor unit 14, and is operated / stopped by an operation of the wireless remote controller switch 40. In addition, when the operating conditions such as the operation mode, the set temperature and the like are set by the wireless remote controller switch 40 and the operation signal is sent, the air conditioner 10 receives the operation signal to the indoor unit 12 to perform the operation based on the operation signal. Is done. The air conditioner 10 is not limited to the wireless remote control switch 40, and may be operated by a wired remote control switch, or may be a driving condition set by an operation of an operation panel provided in an indoor unit. good.

2, the outline of the refrigeration cycle comprised between the indoor unit 12 and the outdoor unit 14 of the air conditioner 10 is shown. Between the indoor unit 12 and the outdoor unit 14, a thick pipe refrigerant pipe 16A for circulating the refrigerant and a thin pipe refrigerant pipe 16B are provided in pairs, each end of which is connected to the indoor unit 12. It is connected to the heat exchanger 18 provided.

The other end of the refrigerant pipe 16A is connected to the valve 20A of the outdoor unit 14. This valve 20A is connected to the four-way valve 24 via the muffler 22A. The accumulator 28 and the muffler 22B, which are connected to the compressor 26, are connected to the four-way valve 24. In addition, the heat exchanger 30 is installed in the outdoor unit 14. This heat exchanger 30 is connected to the valve 20B on one side and the other side to the valve 20B through the capillary tube 32, the strainer 34, the electric expansion valve 36, and the modulator 38. Connected. The other end of the refrigerant pipe 16B is connected to the valve 20B, whereby a sealed circulation path of the refrigerant that forms a refrigeration cycle between the indoor unit 12 and the outdoor unit 14 is configured.

In the air conditioner 10, the operation mode is switched to the cooling mode (dry mode) and the heating mode by switching the four-way valve 24. In addition, in FIG. 2, the flow of the refrigerant | coolant in a cooling mode (cooling operation) is shown with the solid arrow, and the flow of the refrigerant | coolant in a heating mode (heating operation) is shown with a broken line arrow, respectively.

In addition, the outdoor unit 14 is provided with a cooling fan 52 for cooling the heat exchanger 30, which is driven by a fan motor 50 constituted by a DC brushless motor. Operation control of the fan motor 50 is performed by the control unit 60 of the outdoor unit 14.

[Configuration of Fan Motor 50]

The fan motor 50 is comprised by the direct current brushless motor of the three-phase two-pole winding containing the rotor 62 comprised with the permanent magnet, as shown in FIG. That is, three Hall elements 64U, 64V, and 64W are arranged in the vicinity of the rotational track of the rotor 62 at a machine angle of 120 degrees, and the position detection signal by each Hall element is transmitted to the controller 60. Is entered.

The control unit 60 controls the transistor 68U on and off based on the position detection signal from the hall element 64U. When the transistor 68U is on, energization of the U-phase winding 66U is performed. Similarly, the control unit 60 controls the transistor 68V on and off based on the position detection signal from the hall element 64V. When the transistor 68V is on, energization of the V-phase winding 66V is performed. In addition, the control unit 60 controls the transistor 68W on and off based on the position detection signal from the hall element 64W. When the transistor 68W is on, energization of the winding 66W of the W phase is performed.

In the timing chart of Fig. 4, the position detection signal from the Hall element 64U on the U phase is HU, the position detection signal from the Hall element 64V on the V phase is HV, and the position detection signal from the Hall element 64W on the W phase. Are represented by HW, respectively. As shown in FIG. 4, the phases of the HU, HV, and HW are shifted by 120 degrees. In an abnormal state during the constant rotation of the fan motor 50, the interval between these high edges and low edges (T _1). , T ₂ , T ₃ ... T ₁₂ ) are equally spaced.

By the way, in the fan motor 50, the shift of the bonding position of the permanent magnet to the rotor 62, the change of the magnetization of the permanent magnet, the shift of the attachment position of the Hall elements 64U, 64V, 64W, the operation of each Hall element Due to variations in characteristics, the intervals T ₁ , T ₂ , T ₃ ... T ₁₂ of the high edge and the low edge of the position detection signal from each Hall element of FIG. 4 are not equally spaced, but variations occur at the corresponding intervals. do.

Although mentioned later in detail, the control part 60 changes the energization interval to the three-phase winding 66U, 66V, 66W, even if there exists a fluctuation in the space | interval of the high edge and the low edge of the position detection signal of a Hall element as mentioned above. Control the energization timing to minimize the

Moreover, the control part 60 also has a function which detects the actual rotation speed of the rotor 62 based on the position detection signal of a hall element, and calculates the difference between the said actual rotation speed and a predetermined target rotation speed.

[Operation of this embodiment]

Next, the energization timing control process to each winding performed by the control part 60 as an operation | movement of this embodiment is demonstrated.

When the air conditioner 10 starts to operate and starts to drive the cooling fan 52 by the fan motor 50 to cool the heat exchanger 30 of the outdoor unit 14, by the control part 60 of FIG. The control routine starts executing.

After starting the drive of the fan motor 50 in step 102 of FIG. 5, the following normal operation is performed in step 106 until the fan motor 50 is stably operated. In addition, it is considered that the fan motor 50 is stably operated when the state where the difference between the target rotational speed and the actual rotational speed of the fan motor 50 becomes 30 rpm or less continues for 5 seconds.

In this manner, until the fan motor 50 is stably operated, as shown in FIG. 11, the timing at which the waveform of the current hall element changes from the timing at which the waveform of the previous hall element changes (hereinafter, referred to as the last edge) (hereinafter referred to as an edge). Detects the edge interval CCT up to the current edge), turns off the waveform of the energization control signal after (CCT × 4/16) from this edge, and after the (CCT × 10/16) from this edge, The normal operation (step 106) of turning on the waveform is repeated.

In Fig. 11, for example, when the edge interval CCT is T ₆ with respect to the energization of the U-phase winding 66U, the current is supplied from the edge E ₆ to the U-phase winding 66U after (T ₆ × 4/16). The waveform of the control signal is turned off, and the waveform of the energization control signal to the winding 66U of the U phase is turned on after (T ₆ x 10/16) from this edge.

After that, when the edge interval CCT was T ₉ , the waveform of the energization control signal from the current edge E ₉ to (T ₉ × 4/16) later to the winding 66U on the U phase was turned off, and from this edge (T after ₉ × 10/16) and on the waveform of the energization control signal to the windings (66U) on the U. The same applies to the energization of the V-phase winding 66V and the W-phase winding 66W.

When the state in which the difference between the target rotational speed and the actual rotational speed of the fan motor 50 becomes 30 rpm or less is continued for 5 seconds, the fan motor 50 can be regarded as stable operation, and the flow proceeds to step 108 below. In this way, the timing point is determined.

First, each Hall element input of the U phase, V phase, and W phase is measured for (360 + 45) degrees (step 152 in FIG. 6). Next, the sum of the errors of each of the high edge and the low edge for each phase is calculated based on the following equations (1) and (2) (step 154). Note that CCT0 to CCT7 in the following formulas (1) and (2) denote edge intervals CCT0, CCT1, CCT2, ... in the Hall element input shown in FIG. Means.

The sum tH_V of errors at the high edge of V phase and the sum tH_W of the errors at the high edge of W phase are based on the same equation as in Equation 1 above, and the sum of errors at the low edge of V phase tL_V and W phase The sum tL_W of the errors at the edge is calculated based on the same equation as in Equation 2 above.

The edge corresponding to the minimum of the sum tH_U, tL_U, tH_V, tL_V, tH_W, tL_W of the high edge and the low edge of each phase is determined as the timing point (step 156).

In the next step 110 in FIG. 5, the synchronous operation based on the control routine of FIG. 7 is performed as follows.

When the timing point is detected, an average value TGT_CCT of the edge interval CCT between the timing point and one previous edge and the edge interval between the timing point and the previous timing point is calculated (step 164 of FIG. 7) and shown in FIG. 10. As described above, the waveform of the energization control signal is turned off after (CCT × 4/16) from the timing point, and the waveform of the energization control signal is turned on after (CCT × 10/16) from the timing point (step 166). That is, normal operation is performed at the timing point.

On the other hand, when edges other than the timing point are detected, the edge is detected at the average TGT_CCT interval from the timing point, and the waveform of the energization control signal is turned off after T _OFF (= TGT_CCT × 4/16) from the time when TGT_CCT has elapsed. The waveform of the energization control signal is turned on after T _ON (= T6T_CCT × 10/16) (step 170).

For example, in the synthesized waveform of the Hall element input of each phase shown in FIG. 9, when the timing point is determined to be the timing at which the Hall element input of the U phase is turned on, normal operation is performed at that timing point, but timing is performed at another edge timing. The operation unique to the synchronous operation is performed starting from the point.

In this way, it is assumed that the edge is detected at the interval of the average value TGT_CCT of the edge interval between the previous timing point and the current timing point, and the waveform of the energization control signal is turned off after (TGT_CCT x 4/16) from each edge detection timing. Since, after (TGT_CCT × 10/16), the waveform of the energization control signal is turned on, the fluctuation of the energization interval to each winding can be reduced, and problems such as rotational torque fluctuations, vibration, and noise can be prevented.

In this embodiment, since the variation in the relative time interval with respect to the front and rear edges is determined as the timing point in step 108, the average value of the edge intervals between the timing points can be prevented from fluctuating every time the TGT_CCT is calculated. In the case where one timing point is set to one cycle, the fluctuations in the energization intervals between the windings in the cycles can be reduced.

Thereafter, at the time when the fan motor 50 has rotated by a predetermined number (a time point affirmatively determined in step 172 of FIG. 7), the process proceeds to step 112 of FIG. 5, and the target rotational speed and the actual rotational speed of the fan motor 50 are determined. If the difference is greater than 30 rpm, the next step 114 checks whether the average TGT_CCT interval timing (= edge detection consideration timing in synchronous operation) and the actual edge detection timing (average value TGT_CCT × 1/4) or more shift. Check whether there is.

Whether the difference between the target rotational speed and the actual rotational speed of the fan motor 50 exceeds 30 rpm in these steps 112 and 114, or the timing of the average value TGT_CCT interval and the actual edge detection timing are shifted by more than (average value TGT_CCT × 1/4). Until it is determined, the synchronous operation of step 110 is continued.

That is, when the difference between the target rotational speed and the actual rotational speed of the fan motor 50 exceeds 30 rpm (affirmative determination in step 112) and when the magnitude of the rotation variation of the fan motor 50 is detected (in step 114) If affirmative determination is made), the process proceeds to step 116 and returns to normal operation similar to the above-described step 106.

Thereafter, the normal operation of step 106 is continued until the fan motor 50 is stably operated, and when the fan motor 50 is stably operated, the processes of steps 108 to 114 are again executed.

In addition, when the air conditioner 10 stops driving by the driving stop instruction or the like, execution of the control routine of FIG. 5 also ends.

According to the above control routine, the edge is detected at the interval of the average value TGT_CCT of the edge interval between the previous timing point and the present timing point, and from each edge detection timing, after (TGT_CCT × 4/16) of the energization control signal Since the waveform is turned off and the waveform of the energization control signal is turned on after (TGT_CCT × 10/16), fluctuations in the energization interval to each winding can be reduced, and problems such as fluctuations in rotational torque, vibration, and noise are generated. can do.

Further, after the fan motor 50 starts to rotate stably, shifts in the bonding position of the permanent magnets and the like to the rotor 62, fluctuations in magnetization of the permanent magnets and the like, and attachment of the Hall elements 64U, 64V, and 64W. Since variations in the on-off timing intervals of the position detection signals peculiar to the fan motor 50 due to shifts in position, variations in the operating characteristics of each hall element, etc. start to occur, the fan motor 50 as in the above embodiment. After the motor starts to rotate stably, the synchronous operation is started so that the synchronous operation can be executed at an appropriate time according to the situation of the motor.

Moreover, although the said embodiment showed the example which applied this invention to the fan motor in the outdoor unit of an air conditioner, this invention is applied to the DC brushless motor provided in the air conditioner or the DC brushless motor provided in various electrical apparatuses other than air conditioner besides the above. can do.

As described above, according to the present invention, since the energization switching timing to the coil winding is set based only on the reference timing, the fluctuation of the energization interval is reduced by preventing the fluctuation of the switching timing each time from affecting the energization interval. It is possible to prevent problems such as rotational torque stains, vibrations, and joints.

Claims (4)

The detection signal from the plurality of position detectors that detect the position of the rotor sets any of the switching timings of switching from on to off or off to on while the rotor is rotated as a reference timing, Setting the energization switching timing to the plurality of coil windings only on the basis of the set reference timing A control method of a DC brushless motor, characterized in that. The detection signal from the plurality of position detectors that detect the position of the rotor sets any of the switching timings of switching from on to off or off to on while the rotor is rotated as a reference timing, An average value of the intervals of the switching timings between the reference timing in the previous one revolution of the rotor and the reference timing in this one revolution is calculated, From the current reference timing to the next reference timing, switching the energization to the plurality of coil windings based on the calculated timing of the average value interval A control method of a DC brushless motor, characterized in that. The control method of a DC brushless motor according to claim 1 or 2, wherein the switching timing having the least variation in the time interval relative to the switching timing before and after is set as the reference timing. The DC start brush according to claim 1 or 2, wherein the execution start timing is a time point at which the DC brushless motor rotates continuously for a predetermined time or more, wherein the difference between the actual rotation speed and the target rotation speed is equal to or less than a predetermined value. How to control the motor.

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