JPS60234494A - Brushless dc motor - Google Patents

Abstract

PURPOSE:To eliminate a position detector by controlling to switch a current path by utilizing a counterelectromotive force generated in a coil. CONSTITUTION:A pulse signal A corresponding to a counterelectromotive force generated in coils 3a, 3b, 3c upon rotating of a rotor magnet 2 is formed by a pulse detector 10. A switching controller 22 of a current converter 13 is so selected in the internal state that the first drive transistors 4a, 4b, 4c and the second drive transistors 5a, 5b, 5c become the prescribed energizing state by the timing of generating the falling edge of the signal A, and sequentially switch the energizing states of the first drive transistors 4a, 4b, 4c or the second drive transistors 5a, 5b, 5c whenever a trigger signal E is input. Thus, the current paths to 3-phase coils 3a, 3b, 3c are controlled to be switched in response to the rotation of a rotor magnet 2, and rotatably driven in the prescribed direction.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a brushless DC motor in which current paths to three-phase coils are switched by transistors.

(Configuration of Conventional Example and Its Problems) A conventional brushless DC motor requires a position detection element to detect the rotational position of the rotor magnet in order to switch the current path to the three-phase coil. A Hall element that senses the magnetic flux of the rotor magnet is often used as a position detection element, but in order to switch and control the current path of a three-phase coil There were many missed lectures due to the large number of parts and complicated wiring.Especially when using a brushless DC motor as a compressor for an air conditioner,
Hall elements should not be used in high temperature and high pressure conditions.
Reliability and lifespan were significantly reduced.

(Objective of the Invention) The present invention provides a brushless DC motor that performs current path switching control by utilizing a back electromotive force generated in a coil and eliminates the need for a position detection element.

(Structure of the Invention) The brushless DC motor of the present invention includes a rotor having n pairs of magnetic poles (n is an integer), a three-phase coil interlinked with the field magnetic flux of the rotor, and a DC power source connected to the three-phase coil. a first drive transistor group forming a current path to the coil;
a second drive transistor group forming a current return path from the phase coil to the DC power source; pulse detection means for detecting the terminal voltage of the coil to obtain a response signal; and a clock generating a clock pulse of a predetermined frequency. The pulse generating means and the pulse detecting means count the clock pulses in response to the pulse signal, thereby obtaining a count value corresponding to the cycle length Tc of the pulse signal. Tg/6 or approximately Tc/6 based on the counting means obtained every cycle and the count value of the counting means.
energization switching means that generates a trigger signal every time, and switches and controls the current path to the three-phase coils using the trigger signal, The first drive transistor group and the second drive transistor group are brought into a predetermined energized state based on the timing of occurrence of a falling edge, and then,
By sequentially switching the energization state of the first drive transistor group or the second drive transistor group at the signal generation timing, the three-phase The current path to the coil is controlled to be switched between six states, and this configuration achieves the above object.

(Description of Embodiment) FIG. 1 shows an embodiment of the present invention. A rotor magnet 2 attached to the rotor is formed with a pair of N and S poles, and interlinks field magnetic flux with three-phase coils 3a, 3b, and 3c. First drive transistor 4a, 4
The current path from the DC power source 1 to the three-phase coils 3a, 3b, and 3c is switched by controlling the switching of the energization states of the coils 3a, 4c. The current return path from the three-phase coils 3a, 3b, 3c to the DC power supply 1 is switched by controlling the switching of the energization state of the second one-drive trannostars 5a, 5b, and 5c. An electromagnetic force is generated by the field magnetic flux of the rotor magnet 2 and currents to the three-phase coils 3a, 3b, and 3c, and the rotor magnet 2 is rotationally driven in a predetermined direction.

・The noise detection unit 10 is composed of a filter 23 and a waveform shaper 24, and the terminal voltage M of the coil 3a (coil 3a
and the voltage at the connection point of the drive transistors 4a, 5a (7)) to obtain a signal A.

FIG. 2 shows a specific example of the configuration of the XQ response detection section 10. The terminal voltage signal M is divided by the resistors 51 and 52 of the filter 23, the DC component is removed by the capacitor 53, and the high frequency component is reduced by the capacitor 54. The output signal of the filter 23 is input to the converter 57 via the buffer 56 of the waveform shaper 24, which generates a pulse signal A corresponding to the alternating current component of the signal.
(The converter 57 may have hysteresis characteristics to make it more resistant to noise.) As the rotor magnet 2 rotates, a back electromotive voltage is generated in the coils 3a, 3b, 3c, and in a high speed rotation state, the terminal voltage M of the coil 3a is mainly due to the back electromotive force, and the voltage drop due to the current. minutes will be relatively very small. The frequency of the terminal voltage M is proportional to the rotation speed of the rotor magnet 20. When rotor magnet 2 is rotating at high speed (rotation speed is 1000
rpm or higher), the capacitor 53 of the filter 23 is in an alternating current state at the alternating current frequency of the terminal voltage M, and the capacitor 54 acts to integrate the alternating current frequency of the terminal voltage M.

As a result, the terminal voltage M1 is output from the filter and the pulse signal A has a waveform relationship as shown in FIG. 3. (FIG. 3 is an operational waveform diagram for explaining the embodiment.) One cycle of the pulse signal A corresponds to the rotation of one magnetic pole pair of the rotor magnet 2. In addition, the relative phase relationship between the rotor magnet 2 and the three-phase coils 3a, 3b, and 3c at the rising edge and falling edge of the pulse signal A is determined by the relationship between the magnetic flux change and the back electromotive force, and the phase lag of the filter 23. (90°) (when the voltage drop due to current is much smaller than the back electromotive force).

・The output ・Q response A of the response detection unit 10 is input to the first differentiator 35 of the counting unit 11, and ・A differentiated pulse B of a predetermined width is generated from the timing of the falling edge of the Q response signal A. do. FIG. 4 shows a specific example of the configuration of the first differentiator 35, and FIG. 5 shows its operating waveform diagram. The signal A is inputted to the toggle input terminal (T) of the edge trigger type toggle/flip switch 104 via the inverter circuit 101 and the OR circuit 103. Therefore, the frill rough 0 flop 1.04 is inverted by the falling edge of the pulse signal A (from Q+04-"H" to Q+04-"L
).Here, H''' represents a high potential state,
"L" represents a low potential state (the same applies hereafter)
.

Etsutorino j-shaped toggle flirluff 0 flop 10
5 is also inverted Q+os = ”H” to Q105-
(changes to “L”), the output B of the NAND circuit 106 is “
Changes from L” to H”. Therefore, AND circuit 1, 0
Outputs black and cupless CKI to the output side of 2. The clock/grease CKI is the clock/grease generator 1 which will be described later.
This is a ZERES signal of a predetermined frequency generated in step 2.

Flip Flop 1.04.105 Bacro, Kupares C
KI is counted and its state is changed. When both flip-flops 104 and 105 become "H", the output B of the NAND circuit 106 changes to "L", and the output of the AND circuit 102 changes to "L". Clocks and reply CKI are no longer input to the flip-flop 104,
Flip-flops 04 and 105 hold 'H'.

Through such an operation, the first differentiator 35 outputs a differentiated pulse B having a predetermined minute pulse width from the falling edge of the response signal A.

The differential pulse B is input to the second differentiator 36, and from the falling edge of the pulse signal B, a differential signal C of a predetermined pulse width is obtained.
Output. FIG. 6 shows a specific example of the configuration of the second differentiator 3G. Its operation is similar to that of the first differentiator 35, so the explanation will be omitted.

The oscillator 4o of the clock shift generating section 12 is constituted by an RC oscillator using a resistor and a capacitor or a crystal oscillator using a crystal resonator, and outputs a clock pulse CKI of a predetermined frequency.

The first frequency divider 41 performs predetermined frequency division from the clock signal CKI to produce a low frequency clock signal CK2. The second frequency divider 42 has a clock pulse C
K2 is further divided into 1/6, and clock pulse CK3 is obtained.
is creating.

The first counter 37 of the counting section 11 has a clock pulse C.
K3 is counted, and a count value corresponding to one cycle length Tc of the output pulse A of the pulse detection section 10 is obtained.

The count value of the first counter 37 is 1 of the signal A.
It is updated every cycle, and the value is held in the memory 38. FIG. 7 shows a specific configuration example of the first counter 37 and latch 38, and FIG. 8 shows a waveform diagram for explaining their operation.

・An edge-triggered toggle is generated by the output pulse C of the second differentiator 36 generated by the falling edge 1 of the output pulse A of the edge detection section 10.
, 122. ], 23. i, 24,125°126, 1
The internal states of 27, 1.28, and 1.55 are cleared (becomes "L"). After that, AND circuit 12
9 outputs a clock pulse CK3, and flip-flops 121 to 128, 1.65 count up the clock pulse CK3.・When the next falling edge of the signal A arrives, the pulse B of the first differentiator 35 is generated, the output of the AND circuit 129 is held at "L", and the flip-flop, ! 121~] 28, 1.65 is stopped, and its contents are set/reset type flip-flop, 132. ] 33,134.
, 135, 136° 137. 138, 139, 169 are transferred and latched. For example, Furi, Zoflozzo 12
When the internal state of 1 is 'L'' (Q 121 = ”
Since the output of the AND circuit 141 is "L" and the output of the AND circuit 142 is "H", the flip-flop +132 is reset to "L"'. Pulse B of the first differentiator 35 After the latch operation by
The pulse C of the second differentiator 36 causes the tenth counter 3 to
7 flip flora f121~128°165"L
” and counts the clock signal CK3 again. As a result, the count value (dinotal signals D1 to D9) corresponding to one cycle length Tc of the output pulse A of the signal detection section 10 is latched. 38. Furthermore, since the one period length Tc of the pulse signal A is long, the flip-flop 1
65 is inverted (Q+65-“L# to Q +65-”H
When the output of the AND circuit 129 changes to 'L', the counting operation of the first counter 37 is stopped. Latch: The output D9 of the eighth flip-flop 169 corresponds to the count value of the flip-flop 165 of the first counter 37, and D9-“L”′
If D9="H", it means that the rotational speed of the rotor magnet 2 is above the predetermined speed, and if D9="H", it means that the rotational speed of the loaf magnet 2 is below the predetermined speed. This signal D9 can be used when starting the motor, as will be described later. In the following description, it is assumed that the rotor magnet 2 is rotating at a rotational speed higher than a predetermined speed.

The energization switching section 13 is composed of a trigger signal generator 21 and a switching controller 22. After inputting the contents of the latch 38 to the second counter 43, the signal generator 2 inputs the contents of the latch 38 to the second counter 43, and then subtracts (counts down) the contents from the contents every time the clock signal CK2 arrives.
1 when the state of all flip-flops becomes °L”
A trigger signal E of /'p pulse is generated, and the contents of the register 38 are again input to the second counter 43 to continue the above operation. FIG. 9 shows a specific example of the configuration of the second counter 43. When the output signal B of the first differentiator 35 becomes H''', the circuit with reset/clear function, nodriger type toggle/flip, f-flop 1.72, 1
73,174,175,176°177.178.17
9 is the content of the latch 38 (Dl.

D2. D3, D4. , D5. D6. D7. D8) is input, and its internal state (Fl, F2, F3.

F4. , F5, F6, F7. F8) It becomes equal to the content of 38 (the value corresponding to one cycle length Tc of the response signal A). At this time, the output of the AND circuit 171 is L
”.The output B of the first differentiator 35 is “L”.
”, the AND circuit 171 outputs the clock pulse CK2.
is output, and the flip-flops 172 to 179 count the clock response CK2Q. Since the counters 172 to 179 are connected to form a down counter, their contents are decremented every time the clock signal CK2 arrives. That is, the second counter 43
When the outputs F1 to F8 are viewed as binary codes ("L" is 0 and "H" is 1), F1 to F8 start with D1 to D8 as initial values and decrease each time the clock pulse CK2 arrives,
It changes to all 0 (all 'L').

When any one of the outputs F1 to F8 of the Pflozzo 172 to 179 is 'H', the output G of the OR circuit 44 is 'Hn'), and when all of the outputs F to F8 become 'L', the output is G changes to "L".

The output G of the OR circuit 44 is input to the third differentiator 45,
At the timing when the signal G changes from H'' to 'L'', a differential signal E()l) of a predetermined time width generates a signal). FIG. 10 shows a specific example of the configuration of the third differentiator 45. Its operation is basically the same as that of the first differentiator 35 shown in FIG. Here, Edge 1 to Rigger type Toggle Free, Zoflo, Zo 214.
215, the output B of the first differentiator 35 is "H"
When this happens, the flip-flops 214 and 215 are reset (Q = ``)'', and the output E of the third differentiator 45 is set to ``L''. That is, when the output signal B of the first differentiator 35 becomes "H", the trigger signal E becomes "L".

The output E (IJ signal) of the third differentiator 45 is input to the switching controller 22 and the second counter 43. When the trigger signal E becomes "H", the second counter 43 changes the contents of the latch 38 again to
9, and then its contents are subtracted by clock pulse CK2. Therefore, the signal generator 21 outputs the trigger signal E at time intervals according to the contents of the latch 38. Clock Hals CK2i1: This is a signal with a frequency six times that of clock signal CK3 (the frequency division ratio of the second frequency divider 420 is 1/6).
8 is one period length Tc of the pulse signal A of the Noriless detection unit 10
Since it is a dinotal value corresponding to , the short response interval of the trigger signal E is Tc/6 or approximately Tc/6. Note that the signal E is the output of the first differentiator 35 and the signal B
If they occur simultaneously, the third differentiator 45 operates so that the signal E is eliminated (“L”).

The output pulse B of the first differentiator 35 and the output pulse E of the third differentiator 45 are input to the switching controller 22 . 11th
A specific example of the configuration of the switching controller 22 is shown in the figure. Further, its operating waveforms are shown in FIG.

The switching controller 22 includes a first soft lenoster 46, a second shift lenoster 47, and a switching dart circuit 48. The output pulse B of the first differentiator 35 has preset/clear functions, a controller type data input circuit, and pflops 221, 222, 223, 224, .
225, 226 and the preset terminal P or clear terminal CL of the Etsuno trigger type toggle flip-flop 227, and the frizzofrono 7° 221, 22
6. Preset 227 (Q - "H") L, clear the flip-flops 222, 223, 224, 225 (Q = "L'). In other words, due to the arrival of Gres B, 51 - "H", J 2 = ILL”,
J3="L", J4="L", J5="I,"
, J6="H".

Q2□7 --- HIL is selected. Switching controller 22
The outputs J1 to J6 of are respectively amplifiers 6a+6b+6°7
a, 7b, 7cK and corresponding drive transistors 4a, 4b, 4c, 5a, 5b.

The energization state of 5; is controlled on/off (Fig. 1).

J] and 56 are at °'H'', the first drive transistor 4a and the second drive transistor 5c are turned on, and the other drive transistors are turned off. Therefore, the DC power supply 1 → the first Drive transistor 4a → coil 3a
, 3c→second drive transistor 5cm+DC power supply 1, a current path is formed.

Next, due to the operation of the trigger signal generator 21, a trigger signal E is generated when Tc/6 time has elapsed. The output of the flip-flop 227 is Q2□ == IL H+1(S, □
1-"L"), the signal E is output through the AND circuit 229, and the output of the AND circuit 230 is
'L'''.The signal E is output from the flip-flop 221, 222, 223 of the first shift resistor 46.
At the rising edge of the signal E, the data from the data input terminal is input to the clock terminal CK of the flip-flop and outputted. flip flop 2
21, 222 and 223 form a shift register, and when the signal E arrives for the first time, J 1-"
L”.

J2="H" and J3="L". Along with this, the energization state of the first drive transistors 4a, 4b, 4c is switched, the drive transistor 4b is turned on and the transistors 4c, 4a are turned off, and the three-phase coils 3a, 3 are turned off.
The current paths b and 3c are also switched. Note that when the signal E arrives for the first time, the flip-flops 224°225.226 of the second shift reno star 47 do not change.

The trigger signal E is input to the toggle input terminal T of the flip-flop 227 via the inverter circuit 228.

Therefore, at the falling edge of the trigger signal E, the contents of the flip-flop 227 of the switching start circuit 48 are inverted,
Q227 = changes from “H” to Q227-“L#.

The second trigger signal E is transmitted to the output side of the AND circuit 230 (the output of the AND circuit 229 is "L").
, 2nd/at register 4 flip frill rough 0 flop 2:
z, 225.226 is input to the black terminal CK,
When the signal E is raised, the data from the data input terminal is taken into the inside of each flip-flop and outputted. Free ruff 0 flop 221 , 222 , 223
constitutes a shift register, and in the second triage, upon arrival of signal E, J 4 = ”H'', J 5
2'L", changes to J62'L". (Accompanyingly, the energization state of the second drive l/rannostar 5a, 5b + 5c is switched 1, the drive tow/raster 5a is turned on, 5b, 5C is turned off, and the three-phase coil 3a,
The current paths 3b and 3c are also switched. Note that the trigger signal E
At the second arrival of , the flip-flops 22 ], , 222, 223 of the first shift register 46 do not change.

At the falling edge of the signal E, the switching circuit 8-18 flips, the flip-flop 227 is inverted again, and Q22
7''''I('' becomes 0) In this way, the switching circuit 48 inverts the flip-flop 227 at the falling edge of the trigger signal E, and transfers the trigger signal E between the first shift register 4-6 and the second shift register 4-6.
It operates to alternately transmit information to the Nftreno Star 4.7. The first shift register 46 and the second /at register 4 change their internal state and output J every time the trigger signal input via the switching key 1 circuit 48 arrives.
]~J3. J/I to J6 are changed. the result,
As shown in the signal waveforms A, B, E, Jl to J6 in FIG. 2 and 56 become "H" (■ state) due to the first occurrence of the trigger signal, 52 and 54 become "H" (■ state) due to the second occurrence of the trigger signal, and the third occurrence of the trigger signal ]3 and ]4 become PaH''' (state ■), and as a result of the fourth occurrence of trigger signal E, 5 becomes
3 and]5 become "H" (state ■), and only Jl and ]5 become "H" (state) due to the fifth generation of trigger signal E.Next, when the signal A rises, When a falling edge occurs, the initial state (2) is selected. Note that even when the trigger signal E is generated before the falling edge of the pulse signal A, the initial state (2) is selected. Therefore, within one period of the pulse signal A, the current paths to the three-phase coils are controlled to be switched to the ■ state.

Next, the entire rotational drive operation will be explained.

Coil 3a as rotor magnet 2 rotates.

・Q-less signal A corresponding to the back electromotive force generated in 3b and 3c
is generated by the stress detection unit 10. One cycle of the pulse signal A corresponds to the rotation of one magnetic pole pair of the rotor magnet, and the falling edge (or rising edge) of the knockless signal A corresponds to the rotation of the rotor magnet. The relative positions of a r 3 b and 3 c can be detected.The counting unit 11 obtains count values (dinotal signals) Di to D8 corresponding to one period length Tc of the pulse signal A.The energization switching unit 130 and the trigger signal generator 21 Counting section 11
count values D1 to D8 are input, and the bird generates a signal E every time Tc/6 or approximately Tc/6. The switching controller 22 of the energization switching section 13 switches the first drive transistor 4 according to the timing of the falling edge of the pulse signal A.
a, 4b, 4. The internal states of the nostas 5a, 5b, 5c of the second drive transistor 7 are selected so that they are in a predetermined energized state, and each time the trigger signal E arrives, the first drive transistors 4a, 4b, 4c Alternatively, the energization state of the second drive transistors 5a, 5b, 5c (D) is sequentially switched.In this way, the three-phase coil 3
The current path to a, 3bt3c is switched in response to 20 rotations of the rotor magnet, and the rotor magnet and t2 are moved in a predetermined direction.
(As described later, the motor can be started by switching the current path of the coil at predetermined intervals like a synchronous motor or a stepping motor.)
.

As shown in the above example, the back electromotive force (
If the current paths to the three-phase coils are switched using the terminal voltage), structural parts for position detection (for example, Hall elements) are unnecessary, and the structure of the motor becomes extremely simple. In addition, high-temperature equipment such as compressor motors
It can withstand use under high pressure conditions,
Reliability and lifespan are greatly improved.

FIG. 12 shows an embodiment of the present invention including a starting circuit. In the figure, parts representing the same functions as those in the embodiment of FIG. 1 are given the same numbers, and their operations are the same as those in the embodiment of FIG. 1, so a description thereof will be omitted.

In this embodiment, a starting circuit section 14 and a selection section 15 are added. The starting circuit section 14 starts and accelerates the rotor magnet 2 from a stopped state to a predetermined rotational speed.
Ai no no'? Response signal Xi, X2°X3, X4, X5
, X6 and the activation instruction pulse W to the selection unit 15.

The selection unit 15 selects the pulses X1 to X6 of the activation circuit unit 14 from the drive transistors 4a and 4 when the activation instruction pulse W is H''.
b, 4c.

5 a r 5 b + 5 c energization control pulse Y
]-, Y2.

Y3, Y4. , Y5, and Y6. The pulse signals XI, X2, and X3 of the starting circuit section 14 change sequentially to "H"' at predetermined time intervals, and pulses X4, . X5. , X6 also becomes 'H', and the Nonores signal changes sequentially at predetermined time intervals, and... and Hass XI.

X2. Changes in X3 and pulses X4. The changes in X5° and X6 are made to occur alternately. In other words, the current path to the three-phase coils 3a, 3b, and 3c is as described above.
The states are repeated one after another. As a result, the rotor magnet 2 is rotationally driven in steps like a synchronous motor or a chipping motor. The switching time of the current path is gradually shortened, and the rotational speed of the rotor radar net 20 is gradually increased.

Nonores XI, X2. X3. X4. X5. When the switching time width of X6 becomes shorter by a predetermined value, the start instruction pulse W is set to L.
'', and also set all of the starting circuit parts 14's No.4res X1 to X6 to L'', and the 3-phase coil 3a + 3b
Stop energizing r3c. In response to the signals D, 9 from the switch 38 indicating that the rotor magnet 2 is normally accelerated and rotating and the ie)res B from the first differentiator 35, the selection unit 15 selects the output pulses Jl, J2 . J3. J4.
J5. Drive transistor 4.J6. a, 4b, 4c +
5'a, 5b 15c energization control pulse Yl, Y2
, Y3, Y4.

Select to output as Y5, Y6, and then output as J1
~J6 switches and controls the current path of the three-phase coils 3a+3b+38 to perform the rotational drive operation described in the embodiment of FIG. At this time, the output Z of the selection unit 15 is H″(
(indicating normal startup), and the operation of the startup circuit section 14 returns to its initial state and stops.

Further, when the rotor magnet 2 has not been accelerated to a predetermined rotational speed, the output 2 of the selection section 15 is
``H'' Continue. Therefore, the startup circuit section 14 receives the startup instruction and
The signal Z after a predetermined period of time after setting ξres W to L" is "
In the case of "L", the above-mentioned startup and acceleration operations are performed again.In addition, whether or not the rotamac net 2 is rotating at a predetermined rotational speed or higher is determined by the output of the first differentiator 35, as will be described later. The determination is made based on the state of each response B and the highest output D9 of the latch 38.

In addition, resistors 8a, 8b, 8c and a capacitor 9a, which are connected between the three-phase coils 3a, 3b, 3c and the DC power supply 1,
9b, 9c are drive transistors 4a, 4b, 4c, 5
This is to reduce the spike voltage caused by switching the current paths of a, 5b, and 5c.

FIG. 13 shows a specific example of the configuration of the selection section 15.

The selection section 15 includes a speed discriminator 49 and a signal selector 50. Edge-trigger type toggle/fri-ruff 0 flop 306 with clear function of speed discriminator 49;
307 is a startup instruction for the startup circuit section 14 "Has W is "H"
Its internal state is cleared during this period (at startup/acceleration). ('Q 306-"L"+Q307="L
”) o Therefore, the output of the NAND circuit 308 is “H”
”, the output of the OR circuit 309 becomes It HIt, and the output 2 of the input circuit 310 becomes “L”. The outputs of the OR circuit 309 and the output circuit 310 are the Circuits 321, 322
, 323, 324. ．． 325° 326 and AND circuits 327, 328, 329° 330, 331, 332, and the signals Xi, X2 . X3. X
4, X5, and X6 are the outputs of the selection unit 15 (, Y1
=X1°Y2=X2. Y3=X3. Y4=X4. ,Y5
2X5°Y6=X6).

When the start/acceleration period of rotor magnet 2 by [starting circuit section] 4 ends, start instruction/press W and signals X1 to X
6 are all "L", and the rotor magnet 2 is accelerated (-1: stopped. Rotor magnet.

Since the coils 1 and 2 continue to rotate due to inertia, the pulse signal A of the glare detection section 10 is generated by the back electromotive force generated in the three-phase coils 3a+3b+3c. - The fall of the response signal A2. ) of the first differentiator 35 occurs.・The response signal B is inputted to the toggle input terminal T of the flip-flop 3060 via the AND circuit 305, and the flip-flops 306 and 307 gaunt the number of arrivals of the response signal B, and when it arrives three times, the internal state is changed to Q306. =”H”.

Q307-"H" is not set, and the output of the NAND circuit 308 becomes "L". Also, °゛H of Nokless signal B
The flip-flop 304 having a set/reset function is made to hold the highest output D9 of the latch 38 during the period ``.
If c is longer than the predetermined time width (when the rotational speed of the rotor magnet 2 is slower than the predetermined speed), it is 'H'';
When the period length Tc of the pulse signal A becomes shorter than the predetermined time width (when the rotational speed of the rotor magnet 2 is faster than the predetermined speed), it becomes "L". Therefore, when the rotor magnet 2 is rotated and accelerated and its rotation speed exceeds a predetermined speed, the output of the OR circuit 309 becomes II L
II, and the output Z of the inverter circuit 310 becomes H''. As a result, the signals J 1 , J2 , J3 , J4 , J5 , J6 , and J7 of the switching controller 22 become
(Y1=J1.Y2=J2, Y3=J
3°Y4=J4, Y5=J5. Y5=J6).

If the rotor magnet 2 is not started or accelerated normally and the rotor magnet 2 is stopped or rotating at a predetermined speed or less, the pulse signal B of the first differentiator 35 will not be generated. Or the signal D9 of the latch 38 is “H”
II, the output of the OR circuit 309 of the speed discriminator 49 maintains the H'' state, and the output 2 of the input/output circuit 310 maintains the L'' state.

In the above-mentioned embodiment, the counter 11, the energization switching section 13, and the selection section 15 are configured by the flip, shift port, f, and gate circuit, but the present invention is not limited to such components. , a microconbeater may be used in the main parts of the clock pulse generation section 12, the energization switching section j3, the starting circuit section 14, and the selection section J5, and this case is not included in the present invention. .

Note that the rotational speed of the rotor magnet 2 can also be changed by switching and rectifying the AC line voltage (AClooV) to create a DC power supply and changing the DC voltage value. Further, one or both of the first drive transistor 4 a r 4 b r 4 c or the second drive transistors 5 a, 5 b, 5 c is operated on and off at high frequency (... and width modulation off/off operation).
The rotation speed of the rotor magnet 2 may be changed by changing the rotation speed of the rotor magnet 2.

(Effects of the Invention) The brushless DC motor of the present invention switches and controls energization using the back electromotive force generated in the coil.
The motor structure is simple and the wiring is also simple. It can still withstand use under high temperature and high pressure conditions. Therefore, if a brushless DC motor for a compressor is constructed based on the present invention, a motor with a simple structure, long life, and high reliability can be obtained.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing a specific configuration of the Nocles detection section, Fig. 3 is a waveform diagram for explaining the operation, and Fig. 4 is a diagram of the first differentiator. Figure 5 is an operating waveform diagram of the first differentiator, Figure 6 is a diagram showing the specific configuration of
The figure shows a specific configuration of the second differentiator, FIG. 7 shows a specific configuration of the first counter and latch, and FIG. 8 is a waveform diagram for explaining the operation of the tenth counter and latch. , FIG. 9 is a diagram showing the specific configuration of the second counter, and FIG.
Figure 0 shows the specific configuration of the third differentiator, and Figure 11 shows the specific configuration of the third differentiator.
12 is a diagram showing a specific configuration of a switching controller, FIG. 12 is a diagram showing an embodiment of the present invention including a starting circuit, and FIG. 13 is a diagram showing a specific configuration of a selection section. J...DC power supply, 2...Rotor magnet, 3a. 3 b, 3 c-coil, 4 a, 4 b,
4c-first drive transistor, 5ay5b, 5c
...Second drive transistor, 6a, 6b, 6c, 7
a, 7b+7c...Amplifier, 10...Grease detection section, 11...Counter section, 12...Clock/Grease generation section, 13...Electrification switching section, 14...Start circuit section, 15
... selection section, 21... tri is signal generator, 22-...
Switching controller.

Claims (1)

[Claims] A rotor having n pairs of magnetic poles (n is an integer), a three-phase coil interlinked with the field magnetic flux of the rotor, and a current path from a DC power supply to the three-phase coil. a first drive transformer group to form a second drive transformer group, a second drive transformer group to form a current return path from the three-phase coil to the DC power supply, and a pulse detection means for detecting a terminal voltage of the coil to obtain a pulse signal. and clock pulse generation means for generating clock pulses of a predetermined frequency, and counting the clock pulses in response to the pulse signal of the pulse detection means, thereby determining the period length Tc of the pulse signal. a counting means for obtaining a corresponding count value for each cycle of the pulse signal; and Tc/6 based on the count value of the counting means.
Or the bird generates a signal every approximately Tc/6 times,
energization switching means for switching and controlling current paths to the three-phase coils according to the tri-force signal, the riser of the pulse signal of the pulse detection means; The first drive transistor group and the second drive transistor group are brought into a predetermined energized state based on the timing of occurrence of the above trigger signal. By sequentially switching the energization state of the drive transistor group or the second drive transistor group, the current paths to the three-phase coils are changed to 6 within one period of the pulse signal of the contact detection means.
A brushless DC motor characterized in that it is controlled to switch between states.