TW420895B - Method for controlling a DC brushless motor - Google Patents

Abstract

A method for controlling a DC brushless motor which is provided to reduce the change of current flow interval variation of coil winding. After the operation of the motor is stabilized, the input of Hall components for each phase of U, V and W can be tested. The edge with the minimum error of edge timing of the input signal is decided as the timing point. Furthermore, the average value TGT_CCT of edge intervals between the timing point and previous timing point is calculated as the interval detection corner of TGT_CCT between the timing point and the next timing point. After TOFF (=TGT_CCT x 4/16 ) of each edge detection time, the current flowing control signal is cut off, and the current flowing control signal is conducted after TON (=TGT_CCT x 10/16). Therefore, the invention can reduce the change of current flow interval variation for each winding.

Description

V. Description of the invention (1) [Technical field of Ming] The present invention relates to a method for controlling a DC brushless motor, and in particular, to the use of a DC brushless motor such as a fan motor mounted on an indoor unit or an outdoor unit of an air conditioner. Control method of most brushless DC motors with current conversion of coil windings " V [Previous technology] In the past, brushless DC motors have been widely used in indoor and outdoor fan motors installed in air conditioners, or various other types. Electric machine motor. The brushless DC motor detects the position of a rotor including materials including permanent magnets by a plurality of position detectors (such as Hall elements) arranged at equal intervals near the rotation track of the rotor. The on-off time sequence changes the on-current for most of the coil windings used for rotary driving, thereby rotating the rotor. Usually, 1 is synchronized with the on / off operation of the aforementioned detection signal or the current to the coil winding is changed at predetermined time intervals. [Problems to be Solved by the Invention] However, it is often caused by the deviation of the position where the permanent magnet is attached to the rotor, the variation (non-uniformity) of the permanent magnets, the deviation of the position of the position detector, and the position detector. Due to variations in operating characteristics, etc., even if the rotor rotates at a certain speed, there may be variations in the on-off timing (on-off timing) of the detection signal output by the position detector. In this way, the on-off timing of the detection signal does not become an equal interval. When the interval is changed, the on-time timing of the coil windings deviates from the normal timing.

089B W 5. Description of the invention (2) This may cause vibration and abnormal sounds. The present invention is small for the coil winding control method. The setting method is only for the second coil winding, the application method is to change the detection signal within the period of the average interval between the previous time sequence before the rotor is turned on and the rotor is changed, and the application method is, It is a problem of DC brushless motor with minimal variation in the control method of Shen. The non-uniform rotation torque created the solution to the aforementioned problems. Zhixi * Base Egg 4 The author's purpose is to provide a means that can reduce the current interval s α $ 异 之 dc brushless motor means] ΐ! Please detect the position detection signal of the DC brushless 3 at the position of the majority of the rotor in the scope of the patent in the m ^ ^ < period during which the rotor 1 rotates, and change from conduction to conduction _ drag @ ^ >. When any one of the double switching timings is used as a reference, the set reference timing is used as a reference to set the conversion timing for most on-currents. Please control the brushless DC motor in item 2 of the patent scope to detect the majority of the position of the rotor. Detect the output of the position detector. 1 The period of rotation is changed from normal to cut-off or any of the cut-off and change-off timings as the reference timing. The average value of the interval between the reference timing of one rotation and the conversion timing of the current one rotation. According to the previously calculated timing, the time is changed from the current reference timing to the next reference. Pass current. Please control the DC brushless motor in the third item of the patent scope Please select the DC brushless motor in the first or the second item of the patent scope ′ Select the conversion timing between the relative time before and after the conversion time, and set it as the reference timing.

V. Explanation of the invention (3) Furthermore, 'Control method of brushless DC motor in item 4 of the scope of patent application' Control method of brushless DC motor in any one of the scope of patent application items 1 to 3 In the execution sequence, the DC brushless motor continues to rotate for more than a predetermined time in a state where the difference between the actual rotation speed and the target rotation speed is below a predetermined value. The control method of the DC brushless motor in the aforementioned application patent scope item == the detection signal output by the position detector that detects the majority of the position of the rotor is converted from on to Any one of the switching timings of the cut-off switching to the on-time is the reference timing. In addition, only the set reference timing is used as a reference to set the on-time conversion time for most coil windings. For example, the average value of the conversion timing is obtained based on the interval of the reference timing, and the timing of the average interval is set as the on-current conversion timing.

5. Description of the invention (4) Any one of the switching timings is set as the reference timing. Then, the average value of the interval between the reference timing of the previous rotation of the rotor and the conversion timing of the reference timing of i this time is calculated. Sequentially, according to the calculated timing of the average interval, the current reference time = the next reference time sequence is changed for the majority of the coil windings 2. In other words, it is regarded as the interval between the reference time sequence of the current time and the reference time sequence of the next time. The detection signal from the position detector is switched to cut-off or switched from cut-off to continuity. For example, after this conversion (a level I believe the value X4 / 16), the through current to the coil winding is stopped, and the through current to the coil winding is thus started. The average value of the interval of the 4th sequence between the reference timing and the current time sequence is regarded as the bit: Bang sequence :: The average interval is changed from conduction to tangent; ^ ^ The detection signal of the device is based on This conversion sequence change is turned on for most turns, so as to reduce the current flowing to the coil windings, so the obstacles such as uneven torque, vibration, and abnormal noise can be generated: It can also prevent spin and, in the foregoing, The first criterion of the scope of patent application: the setting of the sequence can be arbitrarily, and the conversion time = the base of the invention & 疋, but it should be described in the third scope of the scope of the patent application. The change of the time interval is set in accordance with the quasi-time sequence. The conversion timing of 乂 is set based on the mutated quasi-timing of the relative time interval, which can prevent the calculated reference conversion timing as the base. The average value of the interval is generated every time the calculation is performed, and the conversion timing between the two is different from the adjacent reference. Timing

Page 7 31 0 33 1 420895 ^ V. Description of the invention (5) When one cycle (Cycle) is used, the variation of the frequency of the current interval between the coil windings can be reduced. Furthermore, after the stable rotation of the brushless DC motor starts, it is caused only by the deviation of the attachment position of the permanent magnet to the rotor, and the variation of the magnetization of the permanent magnet. The deviation of the installation position of the position detector, the position detector Variations in operating characteristics, such as variations in the on-off timing interval of the position detection signal peculiar to the DC brushless motor, also begin to occur. Because of this, the start timing of the $ lamp controlled according to the control method of the above-mentioned DC brushless motor should be the predetermined value between the actual speed and the target speed of the DC brushless motor as described in item 4 of the scope of patent application. The following conditions continue for a predetermined time or more (the time when the DC brushless motor starts to rotate steadily). In addition, as the aforementioned position detector, a later-described holler element, a light sensor (a photodiode, a photocoupler, etc.), a magnetoresistive element, and the like can be used. [Embodiments of the invention] Hereinafter, embodiments of the invention will be described. The structure of the air conditioner: The first circle and the second circle indicate the air conditioners (hereinafter referred to as air conditioners) applicable to this embodiment. As shown in FIG. 1, the Jingpo and industrial units are composed of the internal unit 12 and the outdoor unit 14, and the operation / stop control is performed by the operation of the wireless remote control switch 40. Furthermore, "Incremental Aircraft ^ ^ _ π u said" Execution ~ When the machine 10 sends an operation signal via the wireless remote control switch 40 to set the operating conditions, etc., the indoor unit 12 receives the operation signal and executes the operation signal according to the operation signal. Operation 1

V. Description of the invention (6) The industrial control machine 10 is not limited to the wireless remote control switch 40, and can also be operated with a remote control switch. Furthermore, the operating conditions can also be set by the operation of the operation panel provided in the indoor unit. Fig. 2 shows the outline of the refrigeration cycle between the indoor unit 12 of the air conditioner 10 and the outdoor unit u. Between the indoor unit 12 and the outdoor unit j, the refrigerant piping 1 of the thick pipe having the ring refrigerant and the refrigerant piping & 16B of the thin pipe are arranged in pairs, and one end of each is connected to the heat exchanger 1 of the indoor unit 12. . The other end of the refrigerant pipe 16A is connected to a valve 20A of the outdoor unit 14. The 2 0 A is connected to the four-way valve 24 through a muffler 2 2 a. The four-way valve 24 'is connected to a pressure accumulator 28 and a muffler 22 ^ connected to the compressor 26, respectively. The outdoor unit 14 is provided with a heat exchanger 30. One of the heat exchangers 30 is connected to the four-way valve 24, and the other is connected to the valve 2OB via the capillary 32, the filter 34, the electric service room 36, the regulator 38, etc. ^ For the valve 2Ob, the refrigerant pipe is connected The other end of 16β constitutes a closed circulation path of a refrigerant that forms a refrigeration cycle between the indoor unit 12 and the outdoor unit 14. In the air conditioner 10, the operation mode is changed to the air-conditioning mode (drying mode) and the heating mode through the switching operation of the four-way valve 24. In FIG. 2, solid-line arrows indicate the circulation of the refrigerant in the air-conditioning mode (air-conditioning operation), and dotted-line arrows indicate the circulation of the refrigerant in the heating mode (heating operation). The outdoor unit 14 is provided with a cooling fan 52 'for cooling the heat exchanger 30. The cooling fan 52 is driven by a fan motor 50' constituted by a brushless DC motor. The operation control of the fan motor 50 is performed by the control unit 60 of the outdoor unit 14.

V. Description of the invention (7) Structure of fan motor 50: The fan motor 50 is composed of a three-phase, two-pole, brushless DC motor including a rotor 62 having a permanent magnet. That is, three Hall elements 64U, 64V, and 6 4W are arranged at intervals of 120 degrees in the vicinity of the rotation path of the rotor 62. The position detection signal generated by the Hall elements is the turn-in control unit 60. . The control unit 60 controls ON / OFF of the transistor 68U based on the position detection signal output from the Hall element 64U. When the transistor 6 8U is turned on, a current of 66U is applied to the U-phase winding. Similarly, the control unit 60 controls the on / off of the transistor δ8ν based on the position detection signal output from the Hall element 64V. When the transistor 68V is turned on, a 66V on current is applied to the ν-phase winding. Furthermore, the control unit 60 also controls the on / off of the transistor 68W based on the position detection signal output from the Hall element 64W. When the transistor 68W is turned on, a current of 6 W is applied to the W-phase winding. In the timing chart of FIG. 4, the position detection signal output by the U-phase Hall element 64U is represented by HU, the position detection signal output by the V-phase Hall element 64V is represented by HV, and the ff-phase is represented by HV. The position detection signal β output by the Hall element is as shown in Fig. 4. Each phase of HU is deviated by 120 degrees. When the fan motor 50 rotates at a constant speed, the interval between the high and low angles ( T1, T2, T3, ..., T12) become equally spaced. · However, in the fan motor, due to the deviation of the attachment position of the permanent magnet to the rotor 62, the variation of the permanent magnet's writing magnetism, the deviation of the mounting position of the Hall element 64u, 64V, 64F, and the operation of each Hall element Changes in characteristics

Λ ?. 0 89 5 ^ V. Explanation of the invention (8) Different reasons' The interval between the high and low corners of the position detection signal output by each Hall element in Fig. 4 (ΤΙ, Τ2, Τ3 ... .... T12) does not become an equal interval, and the interval also varies. As detailed later, even if there is a variation in the interval between the high and low corners of the position detection signal from the aforementioned Hall element wheel, the control unit 60 will still control the power-on sequence, and will apply the three-phase windings 66U, 66V. The variation of the current interval of 66FF is controlled to the minimum. In addition, the 'control section 60 has a function of detecting a real rotation speed of the rotor 60 based on a position detection signal from the Hall element wheel, and calculating a difference between the real rotation speed and a predetermined target rotation speed. [Effect of this embodiment] Next, a description will be given of the effect of this embodiment by the control section 60 performing the current control processing for each winding. When the air conditioner 10 starts to run, and the fan horse 50 starts to drive the cooling fan 52 to cool the heat exchanger 30 of the outdoor unit 14, the control routine shown in FIG. 5 of the control unit 60 is started. After the fan motor 50 is started to be driven at step 102 in FIG. 5, the normal operation described below is performed at step 106 before the fan motor 50 becomes stable. At this time, if the difference between the target rotation speed and the actual rotation speed of the fan motor 50 is 30 rpm or less for 5 seconds, the fan motor is considered to be running stably. Here, before the fan motor 50 becomes stable, as shown in Fig. 11, the time sequence from the waveform change of the previous Hall element (the corner of the magnetic field 2 below) to the waveform change of the current Hall element is detected. The corner interval CCT 1 of the time sequence (the corner below) passes by the corner this time

V. Description of the invention (9) After (CCT X 4/1 6), the waveform of the current control signal is cut off. After the current corner (CCT X 10/16), the waveform of the current control signal is turned on for normal operation. (Step 106). In Figure 11, for example, for the U-phase winding 66U, if the corner interval CCT is T6, the current from the corner E6 (T6 x 4Π6) will be cut off after the U-phase winding 6 6 U The waveform of the on-current control signal is turned on by the current corner (T6 X 10/16). Thereafter, when the corner interval CCT is T9, the waveform of the current control signal for the phase winding 66 之 is cut off by the current corner E9 after (T9 X 4/16), and the current corner After (T9 X 1 0/1 6), the waveform of the ON current control signal for the U-phase winding 66U is turned on. The same applies to the current passing of the V-phase winding 66V or the W-phase winding 66W. When the difference between the target rotation speed and the actual rotation speed of the fan motor 50 is 30 rpm or less for 5 seconds, the fan motor 50 is considered to be running stably, and the process proceeds to step 108 to determine a time point as described below. First, the Hall element input of the U-phase, V-phase, and phase is tested at (36 0 + 45) degrees (step 1 52 in Fig. 6). Next, the sum of the respective errors of the high and low corners of each phase is calculated according to the following equations (1) and (2) (step 154). In addition, CCT0 to CCT7 in the following formulas (I) and (2) represent the corner intervals CCT0, CCT1, CCT2, etc. of the Hall element input shown in Fig. 8.

The sum of the errors of the high side angles of the phases tH_U = 1 {1 / 4Σ ((χΤ0 to CCT7))-{2 (CCT0 to CCT1)} i +1 {2/42 (CCT0 to CCT7). {S (CCT0 To CCT3)} i

Page 12 V. Explanation of the invention (10) + 1 {3 / 4S (CCT0 to CCT7)}-丨 S (CCT0 to CCT5)} 丨 ... (1) Sum of the low-angle errors of the phase tL_U = 1 {1/4 E (CCT1 to CCT8)}-{E (CCT1 to CCT2)} | + 1 {2/4 Σ ((× Τ1 to CCT8)}-{S (CCT1 to CCT4)} | + 1 {3 / 4 Σ ((χΤ1 to CCT8)}-{E (CCT1 to CCT6)} | ... (2) And, the sum of the errors of the high-angles of the V phase t t the sum of the high-angles of the V and W phases The sum of the errors tH_W is according to the same formula as in the above formula (1), the sum of the errors of the low-angle corners of the V-phase tL_V and the sum of the errors of the low-angle corners of the 1? Phase tL-W is according to the same formula of the above-mentioned (2), Calculate separately. And, the minimum and maximum angles tH_U, tL_U, tH_V, tL_V, tH, and tL_W corresponding to the sum of the errors of the high and low corners of each phase are determined as timing points. (Step 156) Step 110 in Fig. 5 is executed according to the control routine in Fig. 7 below.

When the synchronous operation D detects a timing point, calculate the average value of the angular interval CCT between the timing point and a previous corner and the angular interval between the timing point and the previous timing point TGT-CCT (No. 7 Step 164), and as shown in Figure 10, the waveform of the current control signal is cut off after the timing point passes (CCT X 4/1 6), and the waveform is turned on after the timing point passes (CCT X 10/1 6). The waveform of the current control signal is turned on (step 166). That is, the normal operation is performed from the timing point. On the other hand, when detecting corners other than the timing points, it is considered that the corners are detected by the timing points at the average TGT_CCT interval, and the waveform of the current control signal is cut off after TOFF (= TGT_CCT4 / 16) after the timing points passing TGT_CCT. , After T0N (= TGT_CCT X 10/16), the waveform of the current control signal is turned on

Fifth, the description of the invention (π) (step 170). For example, when the synthesized waveform input by the Hall element input of each phase shown in Figure 9 is determined by the timing of the conduction of the Hall element input of the U phase, the timing point performs normal operation, and the other corner time is Using the timing point as the base point, the unique operation β of synchronous operation is performed. Therefore, the average value of the angular interval between the previous timing point and the current timing point TGT — CCT is regarded as the detected corner. Angle detection time 'After CTGT-CCT χ4 / 16) cut off the waveform of the current control signal' After CTGT_CCTxl0 / 16), the waveform of the current control signal is turned on ', which can reduce the current interval for each winding The variation can prevent obstacles such as uneven rotation torque, vibration, and abnormal noise. Furthermore, in this embodiment, in step 108, the angle with the least variation in the relative time interval between the front and back edges is determined. It is a timing point, so it can prevent the variation that occurs when calculating the average TGT_CCT of the corner interval between timing points. When adjacent timing points are regarded as 1 cycle, the period can be reduced. The winding-current variation interval. In the future, the timing point at which the fan motor 50 rotates a predetermined number of times (the timing point judged by step 172 in FIG. 7 as the default timing point) is moved to step H2 in FIG. 5 to check whether the difference between the target speed and the actual speed of the fan motor 50 exceeds At 30 rpm, check whether the time between the average TGT and the CCT interval (= the time for detecting the corners of the synchronous operation) is offset from the actual corner detection time (average TGT_CCT X1 / 4) in the next step 114. In these steps 112 and 114, the synchronous operation of step 110 is continued until it is determined that the difference between the target rotation speed and the actual rotation speed of the fan motor 50 exceeds

Page 14 42 0895 Description of the invention (: 丨 2) 30rpm or average TGT_CCT interval deviation (average TGT_CCT X 1/4) time and actual edge detection timing, that is, the target speed and actual rotation of the fan motor 50 When the difference is 30rPm (when affirmatively judged by step 丨 1 2) and when the wind is fluctuating greatly (when affirmatively judged by step 丨 14), the steps will be improved. Return to the same normal operation of step 106. After that, the normal operation of step 106 is continued until the fan motor 50 is stably operated. After the fan motor 50 is stably operated, the processes of steps 108 to 14 are executed again. In addition, the air conditioner 10 stops the operation upon receiving the operation stop instruction and the like. The control routine of Fig. 5 is also terminated. According to the aforementioned control routine, the interval of the average value of the angle interval TGT_CCT between the previous timing point and the current timing point is regarded as the detected corner. The detection time of each corner, after (TGT-CCT> < 4/16), cut off the waveform of the current control signal, and the waveform of the current control signal is turned on, so the current can be reduced for each winding. The variation of the interval can prevent obstacles such as uneven rotation torque, vibration, and abnormal sound. Furthermore, since the fan motor 50 starts to run stably, it also starts to cause the deviation of the position of the permanent magnet attached to the rotor 62, Variations in the magnetic characteristics of the permanent magnets, etc., 'Differences in the installation positions of the Hall elements 6411, 64V, and 64W', Variations in the operating characteristics of each Hall element, etc., the on-off time interval of the fan motor 50's unique position detection signal It can be changed according to the foregoing embodiment, and the fan motor 50 can also start to run synchronously after starting stable rotation according to the previous embodiment.

Page 15: n〇33? 20395 ^ V. Description of the invention (13) Synchronous operation is performed at a suitable time based on the condition of the motor. In addition, the foregoing embodiment shows an example of the fan motor applied to the outdoor unit of the air conditioner, but the present invention can also be applied to other brushless DC motors provided in the air conditioner or various electric machines provided outside the air conditioner. DC brushless motor. [Effects of the Invention] As explained before, according to the present invention, since only the reference timing is used as a reference to set the turn-on current conversion timing for the coil winding, it is possible to avoid the variation of each conversion timing to affect the current interval and reduce the current. The variation of the current interval can prevent obstacles caused by uneven rotation, vibration and abnormal noise. [Brief description of the drawings] FIG. 1 is a schematic configuration diagram of an air conditioner according to an embodiment of the present invention. Fig. 2 is a schematic diagram showing a refrigeration cycle of an air conditioner. Fig. 3 is a schematic diagram of a fan motor constituted by a brushless DC motor. Fig. 4 is a diagram showing a waveform of a detection signal of a Hall element. FIG. 5 shows a flowchart of a control routine according to an embodiment of the present invention. FIG. 6 is a flowchart of a processing routine for determining processing at a point in time. * Figure 7 shows the flowchart of the processing routine for synchronous operation. Fig. 8 is a diagram illustrating the corner interval when a Hall element is input. Fig. 9 is a diagram illustrating a synchronous operation in which the time point is determined by the on-off time of the Hall element input of the U-phase. Figure 10 illustrates the timing of the on / off current control signal during synchronous operation.

Page 16 5. Description of the invention (14) Figure. Fig. 11 is a diagram illustrating the timing of on / off current control signals during normal operation. [Description of symbols] 10 Air conditioner 50 Fan motor 6 0 Control section 6 2 Rotor 64U, 64V, 64W Hall element 66U '66V' 66W Winding

Claims (1)

420895 With '----- 88100216 M year 3 a called 1. Application for patent scope • A control method of DC brushless motor' will detect the output signal of the position detector that detects the majority of the position of the rotor in the rotor 丨During the rotation, any one of the conversion timings from ON to OFF or from OFF to ON is set as the reference timing. Only the set reference timing is used as a reference to set the ON current conversion timing for most coil windings. . —A control method of a DC brushless motor, which converts the detection signal output by a position detector that detects the majority of the position of the rotor from ON to OFF or from OFF to ON during the rotation of the rotor 1 Any one is set as the reference timing, and the average value of the interval of the aforementioned conversion timing between the previous one-rotation reference timing and the current one-rotation reference timing is calculated from the current reference timing to the next one. Between the reference timings, the time series of the average interval calculated according to the foregoing calculation is used for the majority of the coil windings. 3. If the method of controlling the brushless DC motor of item 1 or 2 of the scope of patent application, set the conversion timing with the least variation in the relative timing interval between the front and rear conversion timing as the reference timing. 4. If applying for a patent The control method of the DC brushless motor in the first or second range of the scope, the timing when the implementation is started is the timing when the DC brushless motor continues to rotate for more than a predetermined time in a state where the difference between the actual speed and the target speed is below a predetermined value. Stingy A: \ 310331.ptc