JP3420035B2 - Brushless motor drive control device and electric equipment using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a brushless motor used in a range hood, a ceiling-embedded ventilation fan, and the like, and an electric device equipped with the same.

[0002]

2. Description of the Related Art In recent years, a brushless motor has been used as a fan motor with good controllability for mounting on a range hood or a ceiling-embedded ventilation fan that can ventilate with an optimum air volume according to the cooking condition and the condition of the living room. Is required to be adopted.

Conventionally, a drive control device for a brushless motor of this type has a structure as shown in FIGS.
In the case of FIG. 12, 104 is a drive coil U · V · W connected in a neutral non-grounded star, and 102 is a Hall element H1 · that is a position detecting element for detecting the rotational position of the rotor 101.
In H2 and H3, based on the position detection signal from the Hall element group 102, the switching transistors Q1 to Q6, which are a plurality of switching element groups 103, are set to predetermined positions after an electrical angle of 30 degrees from the induced voltage zero cross with respect to the induced voltage phase. The rotor 101 is configured to be driven so as to be an on / off combination, and the plurality of drive coils 104 are sequentially energized with a rectangular wave of 120 degrees to rotate the rotor 101.

In the case of FIG. 15, 105 is a drive circuit for supplying a base current to the transistors Q1 to Q6, 106 is a microcomputer for supplying a predetermined control signal for energization, and 107 is a microcomputer. A timer that outputs a time-out signal when the time set by the microcomputer 106 elapses.
Is a counter for measuring the time interval of the magnetic pole position detection signals from the Hall elements H1, H2, H3.
Calculate the time corresponding to the preset energization overlap angle from the time interval of the magnetic pole position detection signal measured in
The microcomputer 106 controls the timer 107 to rotate the rotor 101 with a certain ratio of overlap during the period when the drive coil 104 is energized.

[0005]

In such a conventional brushless motor as described above, in the case of the configuration shown in FIG. 12, there is a commutation operation in which the conduction phase of the current is switched every 60 degrees in terms of electrical angle. At times, a large drop occurs in the sum of the circulating current until the current of the phase that has been flowing until it reaches zero, and the rising current in the switched phase, causing a large torque ripple and increasing noise and vibration. Therefore, it is required to reduce the torque ripple.

Further, since the energization is cut off when the induced voltage component is high, the period of the circulating current becomes short and abrupt, and when the energization is started when the induced voltage component is low, the rising current becomes abrupt. There is a problem that the rate of change in instantaneous torque becomes large and the effect of reducing noise and vibration is small.
It is required to reduce the torque change rate.

Further, due to the rapid change of the torque ripple and the instantaneous torque, the harmonic component of the torque, especially the 6th order / 1.
Since the second harmonic component becomes large, there is a problem in that noise increases due to resonance with the main body and fan such as a ventilation fan equipped with a brushless motor, and it is required to reduce the harmonic component of torque.

Further, in the case of the configuration as shown in FIG.
The problem that the rate of change of the instantaneous torque is large is similar to that of the above, and in addition to this, unless the conduction angle is expanded to 150 degrees or more, the effect of reducing the torque ripple and the rate of change of the torque will be low, and therefore the current overlapping will occur. If the period becomes long, it is necessary to increase the processing speed of the microcomputer or lower the maximum rotation speed of the motor, which raises the problem of cost increase, and it is required to shorten the overlapping period for energization. .

The present invention solves such a conventional problem and can reduce the torque ripple.
Further, it is possible to reduce the torque change rate, reduce the harmonic components of the torque, and reduce the noise / vibration even if the overlapped period of energization is shortened. It is intended to provide an electric device used.

[0010]

In order to achieve the above object, the brushless motor driving device of the present invention has a first means, in which a switching element ON means is an electrical angle of 35 from the zero cross of the induced voltage with respect to the induced voltage phase. The brushless motor drive controller is characterized in that the switching element is turned on more than once to switch the energized phase .

As a result, it is possible to obtain a drive control device for a brushless motor which can reduce the torque ripple / torque change rate and the harmonic components of torque even when the rectangular wave is energized at 120 degrees.

In order to achieve the above object, the second means detects a signal corresponding to a zero cross of the induced voltage generated in the drive coil of the non-conduction phase of each drive coil or a signal serving as a reference for switching the conduction. And a phase detection means for outputting a zero-cross detection signal, and a zero-cross time interval measuring means for measuring a time interval from the output of the zero-cross detection signal obtained from this phase detection means to the output of the next zero-cross detection signal, An energizing electrical angle setting means for setting an energizing electrical angle, an energizing time calculating means for calculating an energizing time corresponding to the electrical angle set by the energizing electrical angle setting means according to the zero-cross time interval, and the phase detection The zero crossing detection signal of the means is captured, and it is predetermined to energize sequentially in a predetermined direction and order according to the rotor position at that time. Comprising a switching element on means for turning on the predetermined switching element, a switching element off means for turning off the current on the switching element after a lapse of time calculated by the energization time calculation means, before
The electrical angle set by the energizing electrical angle setting means is 120 degrees.
The configuration of the brushless motor drive control device is characterized in that

As a result, it is possible to obtain a drive control device for a brushless motor which can significantly reduce the torque ripple / torque change rate and the harmonic components of torque.

In order to achieve the above object, the third means is characterized in that the switching element off means does not perform an off operation beyond the induced voltage zero cross with respect to the induced voltage phase. Alternatively, the brushless motor drive control device according to the second aspect is configured.

As a result, it is possible to obtain a drive control device for a brushless motor, which has a great effect of reducing noise and vibration even when the energization overlap period is shortened.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a plurality of phase motor drive coils, and a plurality of switching devices connected to the respective drive coils and sequentially energized in a predetermined direction and order. An element, a switching element on means for turning on a predetermined switching element which is predetermined so as to sequentially energize the drive coil in a predetermined direction and order, and a switching element off means for turning off the switching element turned on this time after a predetermined time. The brushless motor drive control device is characterized in that the switching element turning-on means turns on the switching element at an electrical angle of more than 35 degrees from the induced voltage zero cross with respect to the induced voltage phase. At the time of commutation, the circulating current until the current of the phase that was flowing until then becomes zero, and the It has the effect of reducing the drop of the sum of the rising current.

The invention according to claim 2 is a motor drive coil of a plurality of phases, a plurality of switching elements connected to each drive coil for sequentially energizing in a predetermined direction and in order, each of the above Phase detection means for detecting a signal corresponding to the zero cross of the induced voltage generated in the drive coil in the non-energized phase of the drive coil or a signal serving as a reference for switching the conduction and outputting a zero cross detection signal, and a zero cross obtained from this phase detection means Zero-cross time interval measuring means for measuring the time interval from the output of the detection signal to the output of the next zero-cross detection signal, the energizing electrical angle setting means for setting the energizing electrical angle, and the energizing electrical angle setting means The energization time calculating means for calculating the energization time corresponding to the electrical angle set by the above according to the zero-cross time interval, and the phase detection hand. Of the zero-cross detection signal of, and switching element turning-on means for turning on a predetermined switching element that is previously energized in a predetermined direction and order according to the rotor position at that time, and the energization time calculating means And a switching element turning-off means for turning off the switching element turned on this time after a lapse of time, which is set by the energization electrical angle setting means.
The brushless motor drive control device is characterized in that the electrical angle exceeds 120 degrees, and has an effect that the period of the circulating current is long and gentle, and the rising current is also gentle.

The invention according to claim 3 is characterized in that the switching element off means does not perform an off operation beyond an induced voltage zero cross with respect to the induced voltage phase. The brushless motor drive controller has the effect of shortening the energization overlap period.

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

[0020]

【Example】

(Embodiment 1) As shown in FIGS. 1 to 5, reference numeral 1 denotes a brushless motor mounted on a ventilation fan 1a such as a ceiling-embedded type.
It is composed of a rotor 6 having a permanent magnet on its surface and a three-phase drive coil 4 (U, V, W). One end of each drive coil 4 is commonly connected, and the other end of the drive coil 4 is on the upper switching elements 3au, 3av, 3aw and the diode 7.
It is connected to the positive power supply line via au, 7av, 7aw, and the lower switching elements 3bu, 3bv,
It is grounded via 3 bw and diodes 7 bu, 7 bv, 7 bw. Reference numeral 5 designates a drive circuit comprising a switching element ON means 5a for turning on a predetermined switching element 3 and a switching element off means 5b for turning off the predetermined switching element 3, and 2 is a position detecting circuit composed of a primary filter / AC coupling circuit and an adder. In the induced voltage of the U-phase, for example, the Hu signal of the position detection circuit 2 becomes H after 35 degrees in electrical angle from the zero cross at the time of changing from negative to positive.
Then, the Hu signal changes to Low after an electrical angle of 35 degrees from the zero cross at the time of changing from negative to positive. Similarly, the Hv and Hw signals are set to change.
The switching element ON means 5a is the Hu of the position detection circuit 2.
When the signal changes from Low to High, the switching element 3au is turned on, and when it changes from High to Low, the switching element 3bu is turned on. Similarly, Hv · H
w Each switching element 3 based on each signal
It controls av.3aw and 3bv.3bw. Also,
The switching element turning-off means 5b includes switching elements 3au, 3av, 3aw, 3bu and 3bv.
After 3 bw is turned on, it is turned off 120 electrical degrees later.
Here, since the induced voltage phases of the respective phases are different from each other by 60 degrees in electrical angle, for example, Hu changes from Low to High and the switching element 3bv is turned on after 60 degrees in electrical angle after the switching element 3au is turned on. As the electrical angle passes 120 degrees after turning on, Hw changes from High to Low, and after 120 electrical degrees, Hv changes to Lo.
Since it changes from w to High, the drive circuit 5 has a configuration in which the switching element 3 that has been on until then is turned off and then the next switching element 3 is turned on.

The operation of the brushless motor drive controller 1b constructed as described above will be described below. As shown in FIG. 2, the Hu signal of the position detection circuit 2 changes from Low to High after an electrical angle of 35 degrees from the zero cross when the U-phase induced voltage changes from negative to positive. The drive circuit 5 detects this signal, the switching element on means 5a turns on the switching element 3au, and the electrical angle 60
After that, the Hw signal changes from High to Low, the switching element 3bv is turned off, and the switching element 3bw is turned on. Then, after an electrical angle of 120 degrees, H
When the v signal changes from Low to High, the switching element 3au is turned off, and the switching element 3av
Turn on. At this time, as shown in FIG. 3, since the U-phase induced voltage component is lower than in the conventional case, the period of the circulating current flowing through the diode 7au becomes longer, and the U-phase circulating current of the drive coil 4 and V Since the drop in the sum of the phase rising current and the phase rising current becomes small, the torque ripple / torque change rate and the harmonic components of torque can be reduced.

In the first embodiment, as the position detection circuit 2, a circuit constituted by a primary filter, an AC coupling circuit and an adder is used, so that the electrical angle from the zero cross of the induced voltage is 3 degrees.
Although 5 degrees is detected, it may be detected using a Hall element or a Hall IC, and there is no difference in the action and effect.
Further, as shown in FIG. 4 which shows a relative comparison of the torque ripple / torque change rate and the harmonic components of torque when the electrical angle from the induced voltage zero cross to the turning on of the switching element is changed, The torque ripple can be further reduced by increasing the electrical angle, but the effect is reduced when the electrical angle is 45 degrees or more. Also, from the attenuation rate of the 6th harmonic that affects noise vibration, the electrical angle from the induced voltage zero cross to the turning on of the switching element is set to 40 degrees or more and 45 degrees or less, so that the effect is enhanced and the parts are Less susceptible to variations and changes in rotation speed.

(Embodiment 2) The same parts as those in Embodiment 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIGS. 6 to 11, reference numeral 8 denotes a phase detecting means for detecting a signal corresponding to the zero cross of the induced voltage generated in the drive coil 4 of the non-energized phase of each drive coil 4 and outputting a zero cross detection signal. And a Hu signal changes to High as a position detection signal output at the time of zero-cross detection at the time of change from negative to positive in the induced voltage of U phase, for example, by a primary filter / AC coupling circuit and an adder.
Hu signal is L at the time of zero crossing detection when changing from negative to positive.
change to ow. Similarly, the Hv and Hw signals are set to change, and such changes from Hu to Hw, from Hw to Hv, from Hv to H.
The time interval until the change of u is sequentially measured by the time interval measuring means 9 using the timer of the microcomputer 13, and the rotation speed of the rotor 6 is calculated because there is a signal output at intervals of 60 electrical degrees. Reference numeral 10 denotes an energization electric angle setting means for setting an electric angle for energization according to the specifications and the rotation speed range of the ventilation fan 1a on which the brushless motor 1 is mounted. It is stored in ROM. The energization time calculating unit 11 calculates the energization time corresponding to the electrical angle set by the energization electric angle setting unit 10 from the time interval measured by the time interval measuring unit 9. Further, 15 is a commutation electric angle setting means for setting an electric angle from the zero crossing of the induced voltage to the turning on of the switching element 3 according to the specifications and the rotation speed range of the ventilation fan 1a on which the brushless motor 1 is mounted. It is set to 35 degrees, and like the energization electrical angle setting means 10, the microcomputer 13
Stored in the ROM. This commutation electrical angle setting means 1
The time until commutation corresponding to the electrical angle set by 5 is calculated from the time interval measured by the time interval measuring means 9 by the commutation timing calculation means 14. Reference numeral 12 denotes a drive circuit including a switching element ON means 12a for turning on a predetermined switching element 3 and a switching element off means 12b for turning off the switching element 3. The switching element on means 12a is, for example, H of the induced voltage detecting means 8.
It is detected by the timer of the microcomputer 13 that the time calculated by the commutation timing calculation means 14 after the u signal changes from Low to High is turned on, the switching element 3au is turned on, and similarly the phase detection means 8 is detected.
The respective switching elements 3 are turned on according to the output signal of. Further, the switching element off means 12b detects that the time calculated by the energization time calculation means 11 has elapsed by the timer of the microcomputer 13 after each switching element 3 is turned on, and turns off the switching element 3. The other configurations are the same as those in the first embodiment.

The operation of the brushless motor drive control device 16 configured as described above will be described below. As shown in FIG. 7, in the phase change of the U-phase induced voltage from negative to positive, the Hu signal, which is the position detection signal output of the phase detection means 8, changes from Low to High at the zero crossing.
Changes to. At this time, the time interval measuring means 9 measures the elapsed time from the time of the zero cross of the V-phase induced voltage last time from positive to negative, and the electrical angle set by the commutation electrical angle setting means 15 (35 degrees in the steady state). ) Is calculated by the commutation timing calculation means 14, and the energization time calculation means 11 calculates the time corresponding to the electrical angle set by the energization electrical angle setting means 10 (140 degrees in a steady state). And Hu
It is set so that the switching element 3au is turned on after a time calculated by the commutation timing calculation means 14 and the switching element 3au is turned off after a time calculated by the energization time calculation means 11 from the time when the signal changes from Low to High. In addition, as shown in FIG.
When is turned on, the W-phase current gradually decreases according to the U-phase current, and the V-phase current similarly increases. Then, when the switching element 3aw is turned off with the end of the energization time of the W phase, the circulating current flowing through the diode 7aw gradually decreases,
The period becomes longer as in the first embodiment. Then, the V-phase current also decreases accordingly and the U-phase current increases. By repeating such an operation, the drop of the sum of the currents becomes small and the change becomes gentle, so that the torque ripple / torque change rate and the harmonic components of the torque can be greatly reduced.

In the second embodiment, the phase detection means 8 detects a signal corresponding to the induced voltage zero cross by a circuit composed of a primary filter / AC coupling circuit and an adder. It is also possible to detect a signal of, for example, 35 degrees in electrical angle from the induced voltage zero cross, and there is no difference in the action and effect. Moreover, a signal corresponding to the zero crossing of the induced voltage or a signal serving as a reference for switching the energization may be detected by using a Hall element or a Hall IC in the phase detection means 8, and there is no difference in the action and effect. Further, as shown in FIGS. 9 to 11, the switching element is turned on as shown in the relative comparison of the torque ripple / torque harmonic component and the torque change rate when the electrical angle from the induced voltage zero cross to the turning on of the switching element is changed. The torque ripple and the rate of torque change tend to decrease by increasing the electrical angle up to, but the rate of torque ripple / torque change increases by turning off the switching element beyond the induced voltage zero cross of the energized phase. Further, from the relative value of the harmonic component of the torque, if the current is 130 degrees, the electrical angle from the induced voltage zero cross to the turning on of the switching element is 35 degrees or more and 45 degrees or less, 1
If it is energized at 40 degrees, it is 35 degrees or more and 42.5 degrees or less, 145
If it is energized at an angle of 35 to 40 degrees, the effect of reducing noise and vibration is high.

In the present embodiment, the mounting on the ventilation fan has been described, but the present invention is naturally applicable to electric appliances such as range hoods, air conditioners, and air purifiers that can use the same brushless motor. Is.

[0028]

As is apparent from the above embodiments, according to the present invention, the torque ripple
A brushless motor that has the effect of reducing the harmonic components of torque and significantly reducing the torque ripple / torque change rate and the harmonic components of torque even when the energization overlap period is short, greatly reducing noise and vibration. A drive control device and electric equipment using the drive control device can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram of a drive control device for a brushless motor according to a first embodiment of the present invention.

FIG. 2 is a timing chart showing a position detection signal and a gate signal with respect to the induced voltage.

FIG. 3 is a diagram showing the induced voltage waveform / current waveform, the instantaneous torque waveform, and the torque change rate waveform.

FIG. 4 is a graph showing relative comparison of torque ripple / torque change rate and harmonic components of torque when the electrical angle from the same induced voltage zero cross until the switching element is turned on is changed.

FIG. 5 is a schematic diagram showing a state in which a ventilation fan equipped with the drive control device of the brushless motor is installed.

FIG. 6 is a block diagram of a drive control device for a brushless motor according to a second embodiment of the present invention.

FIG. 7 is a timing chart showing a position detection signal and a gate signal with respect to the induced voltage.

FIG. 8 is a diagram showing an induced voltage waveform / current waveform, an instantaneous torque waveform, and a torque change rate waveform.

FIG. 9 is a graph showing a relative comparison between torque ripple / harmonic components of torque and torque change rate when the electrical angle from the induced voltage zero cross at the same 130-degree energization until the switching element is turned on is changed.

FIG. 10 is a graph showing relative comparison of torque ripple / harmonic component of torque and torque change rate when the electrical angle from the induced voltage zero cross at the same 140-degree energization until the switching element is turned on is changed.

FIG. 11 is a graph showing a relative comparison of torque ripple / harmonic components of torque and torque change rate when the electrical angle from the induced voltage zero cross at the same 145-degree conduction to the switching element being turned on is changed.

FIG. 12 is a block diagram of a drive control device for a conventional brushless motor.

FIG. 13 is a timing chart showing a position detection signal and a gate signal with respect to the induced voltage.

FIG. 14 is a diagram showing the induced voltage waveform / current waveform, the instantaneous torque waveform, and the torque change rate waveform.

FIG. 15 is a block diagram of another conventional drive control device for a brushless motor.

FIG. 16 is a timing chart showing a position detection signal and a gate signal with respect to the induced voltage.

FIG. 17 is a diagram showing the induced voltage waveform / current waveform, the instantaneous torque waveform, and the torque change rate waveform.

[Explanation of symbols]

1 brushless motor 1a ventilation fan 1b Brushless motor drive controller 2 Position detection circuit 3 switching elements 3au switching element (U phase upper stage) 3av switching element (V phase upper stage) 3aw switching element (W-phase upper stage) 3bu switching element (U phase lower stage) 3bv switching element (V phase lower stage) 3 bw switching element (W-phase lower stage) 4 motor drive coil 5 drive circuit 5a Switching element ON means 5b Switching element off means 6 rotor 7au diode (U-phase upper stage) 7av diode (V phase upper stage) 7aw diode (W-phase upper stage) 7bu diode (U phase lower stage) 7bv diode (V phase lower stage) 7 bw diode (W-phase lower stage) 8 Phase detection means 9 time interval measuring means 10 Energizing electrical angle setting means 11 Energization time calculation means 12 drive circuit 12a Switching element ON means 12b Switching element off means 13 Microcomputer 14 Commutation timing calculation means 15 Commutation electrical angle setting means 16 Brushless motor drive controller Hu U phase position detection signal Hv V phase position detection signal Hw W phase position detection signal

─────────────────────────────────────────────────── --Continued from the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02P 6/18 F04D 29/00

Claims (5)

(57) [Claims] 1. A multi-phase motor drive coil, a plurality of switching elements connected to each of the drive coils for sequentially energizing in a predetermined direction and order, and the drive coil in a predetermined direction and order. A switching element turning-on means for turning on a predetermined switching element that is previously energized sequentially and a switching element turning-off means for turning off the switching element turned on this time after a predetermined time are provided, and the switching element turning-on means changes the induced voltage phase. On the other hand, the electromotive phase is switched by turning on the switching element at an electrical angle of more than 35 degrees from the induced voltage zero cross.
Brushless motor drive control apparatus characterized by obtaining. 2. A multi-phase motor drive coil, a plurality of switching elements connected to each of the drive coils for sequentially energizing in a predetermined direction and order, and a non-energizing phase drive coil of each of the drive coils. Phase detection means for detecting a signal corresponding to the zero cross of the induced voltage or a reference signal for energization switching and outputting a zero cross detection signal, and a zero cross detection signal obtained from this phase detection means Corresponding to the zero-cross time interval measuring means for measuring the time interval until the zero-cross detection signal is output, the energized electrical angle setting means for setting the energized electrical angle, and the electrical angle set by the energized electrical angle setting means. Energizing time calculating means for calculating the energizing time according to the zero-cross time interval, and capturing the zero-cross detection signal of the phase detecting means, Depending on the rotor position at that time, switching element ON means for turning on a predetermined switching element which is predetermined to sequentially energize in a predetermined direction and order, and this time after turning on the time calculated by the energization time calculating means A switching element turning-off means for turning off the switching element ,
The electrical angle set by the setting means exceeds 120 degrees
The brushless motor drive control according to claim 1,
apparatus. 3. The brushless motor drive control device according to claim 1, wherein the switching element off means does not perform an off operation beyond an induced voltage zero cross with respect to the induced voltage phase. 4. An electric device equipped with the brushless motor drive control device according to claim 1. Description: 5. The electric device according to claim 4, which is any one of a ventilation fan, a range hood, an air conditioner, and an air purifier.