JPS60125190A - Motor - Google Patents

Abstract

PURPOSE:To prevent the thermal damage of a drive transistor and to improve the lead-in matching of controlling the speed of a motor by stopping the current correcting operation by a temperature detector when a deceleration torque is generated. CONSTITUTION:The position of a motor moving unit is detected by a position detector 9, the detected output is inputted to a distributor 10 to control the energization of drive transistors 6-8. The temperatures of the transistors 6-8 are detected by a temperature detector 11, and when the temperatures become the prescribed value or higher, the supply currents to the coils 3-5 are corrected to be reduced by a current corrector 45. The current distribution to the coils 3- 5 is switched to the production of acceleration and deceleration torques by a distribution switch 32, and when the deceleration torque is generated, even if the detected temperature of by the detector 11 is the prescribed value or higher, the current correcting operation of the corrector 45 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a brushless motor in which current paths to multiple phase coils are electronically switched using transistors.

Conventional configuration and its problems Brushless motors do not use a brush commutator, so there is no commutation noise, and they have a long life and are highly reliable, and have been widely used in audio and video equipment. ing. In the motors used in these devices, the current path to the coil is switched by a non-contact position detection table g and a plurality of drive transistors that are activated in response to the output thereof. Further, the operating current of the drive transistor is controlled so that the current supplied to the coil is at a predetermined value (a value corresponding to the command signal). As a result, collector loss occurs in the drive transistor, and the temperature of the transistor increases, resulting in thermal breakdown and shortened life. Case, Drive 1 - When transistors and resistors are integrated into a single silicon chip, the heat generated by the multiple drive transistors is concentrated within the chip.
thermal damage is likely to occur.

In particular, if the motor becomes mechanically long due to equipment failure, if the drive transistor is short-circuited due to thermal breakdown, excessive current will be supplied to the coil, leading to accidents such as coil burnout. , had become a problem.

As a way to solve these problems, the temperature of the drive transistor is detected and the temperature is set to a predetermined value (130 degrees).
If this is the case, it is conceivable to reduce the output current of the drive transistor. If such a thermal protection circuit is provided, a highly reliable motor can be realized in which thermal destruction of the drive transistor can be completely prevented.

Normally, motors used in audio/visual equipment are speed controlled, and the acceleration torque accelerates the motor moving part to a constant speed, and if the speed is too high (overshoot), it is decelerated. However, when such a method is used, the heat generation of the drive transistor becomes extremely large when deceleration torque occurs9. The temperature of the transistor rises rapidly.As a result, the aforementioned thermal protection operation disturbs the current supplied to the coil, resulting in a long pull-in time for speed control and, in severe cases, hunting.

This will be explained. FIG. 1 is an electric circuit diagram showing the connection between a coil (3) and a drive transistor (6), which are part of the motor, and FIG. 2 is a waveform diagram showing the operating voltage .oB. When the motor is accelerated, carp tv (3
) a back electromotive force is induced. When acceleration torque is generated, the drive transistor (6) supplies the current 1a to the coil (3) at the timing shown in the shaded area in Figure 2 (al) (the shaded area is the coil due to the current Ia). under)
. On the other hand, when deceleration torque is generated, the drive transistor (6) supplies the current 1a to the coil (3) at the timing shown in the shaded area in FIG. 2 tb*. Drive transistor (6)
The heat generation (collector loss) of is due to its operating voltage V. Since it is generated by the product of E and the current Ia, when considering the same current, the heat generated when deceleration torque occurs is significantly greater than the heat generated when acceleration torque occurs.

As a result, when deceleration torque occurs due to motor speed overshoot, the drive transistor (6) generates a large amount of heat and temperature rises, causing the thermal protection circuit to operate and adversely affecting control pull-in.

Purpose of the Invention The present invention takes these points into consideration, and provides a motor that has a protective function that prevents thermal destruction of the drive transistor in the event of a failure such as a motor lock, but that does not adversely affect the pull-in of speed control. The purpose is to provide the following.

Structure of the Invention The present invention includes a position detection means for detecting the position of a movable part of a motor, a plurality of phase coils, a drive transistor group for supplying current to the coils, and the above positions replaced.

distribution means for distributing and controlling energization of the group of drive transistors in response to the output of the output means; distribution switching means for switching current distribution to the coil p between generation of acceleration torque and generation of deceleration torque; temperature detection means for detecting the temperature of the coil; current correction means for correcting the current supplied to the coil when the detected temperature exceeds a predetermined value in response to the output of the temperature detection means; When a deceleration torque is being generated, the device is provided with means for preventing the current correction operation of the current correction means even if the detected temperature is equal to or higher than the predetermined value, thereby achieving the desired target. This has been achieved.

- Further, in another configuration of the present invention, in addition to the position detection means, coil, drive transistor group, distribution means, distribution switching means, temperature detection means, and current correction means, a variable output DC voltage is obtained from the DC power supply. A switching type voltage conversion means, an operation detection means for detecting the operating voltage of the drive transistor when it is energized and controlling the output voltage of the voltage conversion means in accordance with the detection signal, and the distribution switching means are used to reduce the speed. In the case where torque is generated, the output voltage of the voltage conversion means is set to a predetermined value or a maximum value, and means is provided for preventing the current correction operation even if the detected temperature is equal to or higher than the predetermined value. This achieved the intended purpose.

Description of examples FIG. 3 is an electrical circuit diagram representing one embodiment of the present invention.

In Fig. 3, (1) is a DC power supply, (2) is a field magnet (field means) having multiple magnetic poles, (3 bars 4), (5) is a 3-phase coil, (6) (7) (8) is a drive transistor, (9) is a position detector that detects the position of the motor moving part (magnet (2)), and αQ is a drive transistor (6) that responds to the output of the position detector (9). (b) is a temperature detector that detects the temperature of drive transistors (6), (7), and (8); magnet)
(2) This is a speed detector that detects the rotation speed of ).

A specific example of the configuration between the speed detectors is shown in FIG.

An alternating current signal with a frequency proportional to the rotational speed of the motor movable part is obtained by the frequency generator (al), and is output by the period detector (to).
A voltage signal corresponding to the cycle of the AC signal is obtained. The alternating current signal (or its frequency divided signal) from the frequency generation section IF) is input to the phase difference detection section I41 together with the reference frequency signal from the reference frequency generation section IF), and a voltage signal corresponding to the phase difference between the two is obtained. . Output of period detection section 04 and phase difference detection section -
The resulting output is added and synthesized in the synthesis section -. The output of the synthesis section is inputted to the absolute value detection section (along with the reference voltage signal of the reference voltage section) and the comparator section.
In 7), a voltage proportional to the absolute value of the voltage difference between the two human power signals is output, and in the comparator section), a digital signal B corresponding to the sign of the difference voltage is obtained. Absolute value detection section (
The DC level of the output 2) is shifted by the level shifter 2, and a voltage signal A with zero volts as a reference is output.

The voltage signal A of the speed detector (2) is input as a command signal V to the trouble current control Ncυ of the distributor (10), and is input to the current detector (2).
) and outputs a current i according to the difference between the two. FIG. 5 shows a specific example of the configuration of the current controller 0η. Differential transistor (102X103) (
104X105) voltage input to the base side ■1 and ■
2, the current of the current source (101) is distributed to the collector side, and the collector current is distributed to the collector side of the transistor (106
The difference current is amplified by the transistor (108) and the transistor (107) is compared by the current mirror ~.
109) and is outputted via the current mirror (110).

The output i of the current controller 6v is input to a distribution switch o4 constituted by an electronic switch circuit. A specific example of the configuration of the distribution switching means is shown in FIG. When the digital signal B of the speed detector @ is at a low potential (zero port), the base voltage of the differential transistor (127) is sufficiently lower than the base voltage of the transistor (126), and the voltage input to the a terminal is The current is output to the b terminal.Furthermore, when the digital signal B becomes the high voltage power supply voltage V8), the transistor (128) is turned on and the differential transistor (126) is turned on.
) becomes sufficiently lower than the base voltage of the transistor (127) and is output to the input terminal C terminal.

The output on the b terminal side of the distribution switch (2) becomes the common emitter current of the transistor (to) serving as the first selector.

Also, the output on the C terminal side is the common emitter current of the transistor (2) II@υ of the second selector (2).

In other words, the speed detector □□□ digital! In response to signal B, the output of the current controller 6 is 1. Switch the passage and go to the first
The selector (generating acceleration torque) and the second selector (generating deceleration torque) are operated in a complementary manner.

- Each base terminal of the transistor (g) auxiliary flame of the first selector) is connected to the ho/L/element sh
) @ (positive phase output side) output voltage is applied respectively. The Hall elements Ql... sense the magnetic flux of the magnet (2) and generate an analog voltage signal according to its rotational position. Transistors (G), (B), and (7) distribute the common emitter current to each collector current according to the difference in their base voltages, and the collector current of the transistor with the lowest base voltage is the largest, and the collector current of the other transistors is becomes zero.

Similarly, the transistor (to) (6) of the second selector (b)
The output voltage of the other (negative phase output side) of the Hall element C2υ@@ of the position detector (9) is applied to each base terminal of ) (b). Therefore, transistor −Ql)
distributes the common emitter current to each collector current according to the difference in their base voltages, and the collector current of the transistor with the lowest base voltage becomes the largest, and the collector currents of the other transistors become zero.

The valley collector current of the transistor (to) θ2 of the first selector ■ or the transistor of the second selector (→) (6
)O]) each collector current of the drive transistor (6)
(7) and (8), the current is amplified and supplied to the coils (3), (4), and (5) (to the first selector), and the second selector diagram. The activation is determined by the distribution switch (). carp/l'
(3) (4) The current supplied to (5) is detected as a voltage drop across the resistor (6) of the current detector (2), and is passed through the resistor (b) of the current modifier (b) to the current regulator. The operation manually applied to Cυ (to the current corrector) will be described later. ) As a result, the current controller 0, the distribution switch (to), the 1st
A feedback loop is formed by the drive transistor (6) (7 bar 8) and the current detector (7), and the selector (1 or 2) The current 1a supplied to the motor is set to a current value corresponding to the value 1 of the output A of the speed detector @ (actually, the operation is performed so that V shown in the figure and v2 become equal). As a result, the influence of variations in hFE of the transistors (6, 7, 8), etc. is significantly reduced.

Further, as the magnet (2) rotates, the Hall element I:
The drive transistors (6) (7
) Controls and switches the energization of <8).

Note that the capacitor (c) is provided for phase compensation (to prevent oscillation) of the feedback loop mentioned above. Also, Koi! (3
) (4) Resistor G1 connected in parallel with (5)...
The series circuit of capacitor Q5';

Next, the configuration of the temperature detector (11) and current modifier
The operation will be explained. A constant current source (201), a constant voltage diode (202c), and a transistor (203) of the temperature detector (11).

The resistor (204x205) produces a predetermined reference voltage 5 (approximately 490 mV) that does not change depending on temperature, and is applied between the base and emitter of the temperature detection transistor (206) (output of the speed detector (6)). (If B is low potential)
.

Temperature detection transistor (206) U drive transistor (
6) (7) The temperature of (8) is detected (for example,
Temperature detection transistor (206) and drive transistor (
6) By integrating (7) and (8) into an integrated circuit (IC) on a single silicon chip, temperature can be easily detected). The collector current 12 of the temperature detection transistor (206) changes in accordance with the temperature of the drive transistors (6), (7), and (8), and the current value increases rapidly as the detected temperature increases.

The output side of the constant current source (209) and the current mirror circuit (
The input terminal of the transistor (207×208) is connected, and its output current i4 is as follows.

(1) When the temperature of the drive transistor is low, 12≦I
If it is 3, then 14=0.

(ill l/Am The temperature of the transistor is a predetermined value 'r
, (v, is the value corresponding to t16, usually T, = 130
℃), +2 > 13,
A current i4 that is proportional or approximately proportional to the difference between the detected temperature T and the predetermined value T is output.

That is, Here, k is a proportionality constant.

The output i4 of the temperature sensor 0V is the resistance (to) of the current modifier (
goods). Since the operation of the feedback loop described in 1g11 is V,=V2, the current Ia supplied to the coil is as follows. Here, R42 and R44 each have a resistance minus one value, and usually R44 total 100/R42 (
In this example, R44=390Ω, R42=0.39Ω
). Therefore, when the temperature of the drive transistor is below the predetermined value T, since 14-=0, the current 1 a =V, /R42 corresponding to the command signal V1 is supplied to the coil.

Furthermore, when the temperature of the drive transistor becomes higher than the predetermined value T1, j4 increases in proportion to the detected temperature, so Ia is smaller than the value VH/R42 corresponding to the command signal ■ by the value corresponding to the detected temperature. The current correction operation is performed so that

Further, when the output B of the speed detector (b) is at a high potential, the transistor (210) of the temperature detector Oη is not turned on, and the base and emitter of the temperature detection transistor (206) are short-circuited. As a result, even if the temperature of the drive transistor becomes higher than the predetermined value T, the output i4 of the temperature detector αυ
is always zero, and the above-described current correction operation is no longer performed.

First, a description will be given of the thermal protection operation when a mechanical lock of the motor occurs. Since the magnet (2) is stopped, the output At-1 of the speed detector @: maximum value (approximately 04V
), the output B becomes a low potential (OV).

Therefore, the distribution switch (to) connects the input terminal a and the output terminal to operate the first selector (g), and at the timing when the acceleration torque is generated, the coil/u (3) (4) (
5) Distribute the flow. The current 1a to the coil is
A current proportional to the command signal ■1 is supplied by the feedback operation by the current controller 6υ, the distribution switch Q4, the first selector Z, the drive transistors (6) (7) (8), and the current detector). Ru. That is, the drive transistor (6) (
Either 7) or (8) supplies a current of approximately IA to the coil. For example, assuming that the drive transistor (6) is supplying current to the coil (3), the voltage of the DC power supply (1) vs. the coil.

The value obtained by subtracting /I/(3) and the voltage drop across the resistor (6) is the operating voltage V of the drive transistor (6). It becomes E.

Now, if ■5-12V and the voltage drop is 5V, VCE
=7V9, and the heat generated by the drive transistor (6) is 7W. Therefore, the chip temperature T of the drive transistor (6)
is rising. When T>T (predetermined value), the output i4 of the sweetfish degree detector av is large (j4>0), and the current Ia supplied to the coil is reduced by the action of the current correction operation.

As the current 1a decreases, the operating voltage VcE of the drive transistor (6) increases, but the collector loss ■. E-I a
The current is adjusted so that it becomes smaller. As a result, the temperature of the drive transistor (6) does not increase significantly beyond the predetermined value T. Therefore, excessive temperature rise and thermal breakdown of the drive transistor can be prevented.

This thermal protection effect is not limited to when the motor locks up, but even when the motor load is abnormally increased and the motor is rotating at low speed, the temperature detector Oυ and current correction operation described above operate, and the drive transistor prevent thermal damage.

Next, we will explain the retraction operation of speed control (and phase control).At the time of starting and accelerating the motor, the speed detector α
The output B of 4 supplies a common emitter current to Ov and the first selector L of the distribution switch (2).

In the transistor facing the first selector, there is a Hall element O! at each base of cg)-. 4 positive-phase outputs are applied to υ, and the drive transistor corresponding to the output becomes active, causing the coil/' (3) (4) (5
) is distributed to #. When the motor movable part (magnet (2)) is accelerated and its rotational speed reaches a predetermined value, the output A of the speed detector (2) decreases and the current Ia to the coil becomes smaller.

Due to the pull-in of speed control (and phase control), the motor moving part becomes transiently faster than the desired rotational speed (overshoot). At this time, the output B of the speed detector (6) changes from OV to v5), and the switch of the distribution switch (9) changes, and the output i of the current controller (5) changes to the second selector (2). ). The voltage applied to each base of the Hall element υ(
2) The negative phase output of (a) is electrically 180 degrees higher than the voltage applied to each base of the transistor (to) cll of the first selector (the positive phase output of the Hall element ρ). It has a phase difference of °. As a result, the second selector (to) selects the drive transistor (6/7) to generate deceleration torque.
(8) Distribution control of energization.

When deceleration torque occurs (output B of speed detector (6) is ■5
), the transistor (210) of the temperature detector Qυ is turned on, and the output i4 of the temperature sensor Qυ becomes zero. That is, when deceleration torque occurs, temperature detection operation and current correction operation are not performed regardless of the IA drive transistor temperature. Therefore, a current 1a proportional to the output of the speed detector Q4 is supplied to the coil, generating a deceleration torque proportional to Ia.

As the movable part of the motor is increased in speed, the output A (V, ) of the speed detector @ becomes smaller, and at V, = O, the digital signal B of the speed detector (B) changes and changes from v5 to OV.
), the distribution switch) outputs the output i of the current controller 6υ as the first
The energization of the drive transistors (6), (7), and (8) is distributed and controlled so as to generate acceleration torque. The rotational speed (and rotational phase) of the motor movable part reaches the desired value, and the speed control (and phase control) reaches a stable state.

In this way, if the current correction operation is not performed when deceleration torque occurs, the motor will start and accelerate stably even when the ambient temperature is high, and the motor will reach a stable state of speed control (a+ < and phase control). To go.

This will be further explained. Now, temperature detectors a and t
Assuming that there is no positive transistor (210), consider the case where the temperature detector (IIJ) is always working.The terminal voltage of the coil when generating deceleration torque is shown in Figure 2 (L
+) The operating voltage of the drive transistor when p1 current is energized. E becomes very large. Now, DC fM, voltage of source (1) is V5=12■, and peak value of back electromotive force is V.
, =7V, and if the voltage drop due to the current at the time of the change is iv, then VoE=12+7-1=18V. This value is the operating voltage VcE when acceleration torque is generated by the same current.
=12-7-1=4V and 4.5i& are also large. Therefore, heat generation for the same current 1a is 4.5 times greater when deceleration torque occurs than when acceleration torque occurs. As a result, when a transient speed overshoot occurs, the temperature rise of the drive transistor temporarily increases sharply. When the temperature of the drive transistor becomes greater than a predetermined value T, the temperature detector Uυ and the current modifier) operate to reduce and modify the current Ia supplied to the coil. When the current 1a becomes smaller, the value of deceleration torque becomes smaller.
It takes time to decelerate to a predetermined speed.

When deceleration torque occurs, the rotational speed of the motor is faster than the target speed, so the rotational phase advances. Therefore, even if the rotational speed of the motor is decelerated and becomes equal to the target speed, in order to return the advance of this rotational phase to a predetermined value,
Continue to try to generate deceleration torque. In this way, during the transient stage of speed control, the temperature detector Q〃 and the current modifier) operate to reduce and correct the supply current 1a to the fill, which increases the deceleration time and the control pull-in time. I end up. Furthermore, if the heat generation and temperature rise of the drive transistor at the time of occurrence of deceleration torque is extremely large, the degree of current correction described above will not be large enough, and not only will sufficient deceleration torque not be generated, A vicious cycle also occurs in which the temperature rise becomes even greater because the time required to generate the deceleration torque becomes longer. As a result, in the worst case, speed control (and phase control) may fail and hunting may occur.

On the other hand, as shown in this embodiment, if the current correction operation is not performed when deceleration torque is generated, it is possible to decelerate in a short time with a sufficiently large deceleration torque, and the temperature of the drive transistor increases. The rise becomes smaller. As a result, the pull-in time of speed control (and phase control) is shortened, and the unstable phenomenon in control pull-in as described above does not occur. Normally, rotational speed overshoot is a transient phenomenon until the speed control (and phase control) reaches a stable state, and the speed control settles into a stable state after a temporary overshoot or undershoot.

Therefore, even if the temperature of the drive transistor temporarily rises above the predetermined temperature T, R, no problem occurs because the temperature becomes lower than T, in the stable state of speed control.

FIG. 7 shows an electrical circuit diagram representing another embodiment of the present invention. In Figure 7, DC power supply (1), magnet (2)
, three-phase carp/I/(3) (4) (5), drive transistor (6) (7) (8), position detector (9),
The configuration and operation of the distributor α0, the temperature detector aη, and the speed detector @ are the same as those in the embodiment shown in FIG. 3 described above, and their explanation will be omitted. In this embodiment, in addition to each queen element, an operation controller (transistor) that detects the lowest operating voltage value among the drive transistors (6), (7), and (8), and an operation controller α
It is equipped with a switching type voltage converter am that changes the output voltage vM according to each output.

Next, the operations of the operation controller □□□ and the voltage converter Q4 will be explained. Voltage converter tJ4 is a DC power supply (1)
Carp/L/ (3) from the positive terminal (vs-12■) of
(4) A switching transistor (b) constituting a semiconductor switching element for power supply control, whose emitter-collector path is inserted in series in the power supply circuit leading to the common connection terminal in (5), and a flywheel diode (i) ), an inductance element ■, a smoother consisting of a capacitor, an operation controller (13), a resistor (7υ) that converts the output current to voltage, and an oscillator (2) that generates a triangular wave signal tube of a predetermined frequency (about 94.4KHz). , a comparator g3, and a capacitor (7+9).

The operation controller (2) extracts the lowest value of the operating voltage of the constant current source 671, resistor, and diode 11) that generate a reference voltage signal, and the drive transistors (6), (7), and (8). It is composed of a detection transistor I3-1, a comparison transistor, a current mirror circuit consisting of a diode (2) for inverting and amplifying the output currents of the six comparison transistors, a transistor ring, and a resistor @ ring.

The output voltage VM of the voltage converter Q4 changes in relation to the ratio of on time and off time (substantive duty ratio) of the switching transistor Q3). When this switching transistor 181) is on, it becomes v1zv8,
A DC power supply (1) supplies current to the load side through an inductance element ring. switching transistor eII)
When is off, the flywheel diode 6 frame is on, supplying the inductance element, especially the stored energy, to the load side. As a result, the output voltage VM of the voltage converter Q has a value corresponding to the duty of the on time of the transistor 6I).

The output voltage of the voltage converter ah ■8 is the 8-phase carp tv (3
) (4) (5) and drive transistors (6) (7
) (8), and the driving transistors that are sequentially activated are switched according to the operation of the aforementioned distributor gQ.

The operation controller a4 is a drive transistor (6) (7) (
8) operating voltage (here collector-emitter voltage v
cE), this will be further explained.

The current I5 of the six current sources is connected to the resistor and the diode @...I
υ (when the output current i6 of one comparison transistor is zero), the drive transistor (6) (7) (8)
A reference voltage signal of a predetermined voltage value V=R−I+3VD·(3) 5685 is generated from the common connection terminal (emitter terminal in this embodiment) of. Here, R58 is a resistor (2
), ■D is the forward voltage drop of the diode (approximately 0.7
V). Each base terminal of the detection transistor InIM is connected to each output terminal of the drive transistor (6) (7) (8), each emitter terminal is connected to the pace terminal of the comparison transistor ring, and each collector terminal is connected to the lowest potential point (
connected to earth potential). Furthermore, the emitter terminal of the comparison transistor is connected to the above-mentioned reference potential point (point of signal 4). As a result, the drive transistor (
0) The operating voltage of (788) is two times the forward voltage between the emitter and base (2■D) than the reference voltage v45 mentioned above.
When it becomes smaller, the comparison transistor becomes active and outputs the current i6 to the collector side.

Comparison 1 The output current i6 of the range nut is the diode -
, transistor, and resistor @-, and is inverted and amplified, and outputted as an operation detection signal 17.

The output current 17 of the operation controller is determined by the resistance of the voltage converter q4 (
c) is converted into voltage v5. The voltage v5 and the triangular wave signal of the oscillator @ are compared by a comparator q3 to obtain a pulse signal with a duty corresponding to the voltage 5. The switching transistor is turned on and off by the pulse signal, and the output voltage of the voltage converter is variably controlled.

As a result, a second feedback loop is configured by the operation controller α1, the voltage converter (141, and the coil) (3) (4) (5), which detects the operating voltage of the drive transistor described above, and detects its operation. The voltage is made equal to or approximately equal to a predetermined value.

This will be further explained. Speed detector @ output A (■
, ) becomes large, the first feedback loop (current controller C
〃、Distribution switch 64、first selector or second selector■、driving transistors (6) (7) (8) and current detector)) supply current I to the coil.
a becomes large, the operating voltage of the drive transistor becomes small, the output current 16 of the comparison transistor ^4, and therefore the operation detection 1M +j'i, becomes large, and the voltage v5 becomes large. transistor t8
]) becomes larger, the output voltage of the voltage converter ◇ 8 becomes larger, and the operating voltage of the drive transistor becomes larger. The same applies to the opposite case.

Note that the capacitor q8 of the voltage converter α is provided for phase compensation (stopping oscillation) of the second feedback loop.

In this way, by detecting the operating voltage of the drive transistor,
voltage converter (b) so that the value is a predetermined small value.
If the output voltage .mu.M is flexibly controlled, the collector loss in the drive transistor will be significantly reduced. In addition, since the required output voltage VM is obtained by turning the switching transistor (b) on and off and changing its on-time ratio, there is a loss associated with voltage conversion of the converter θ. is extremely small.As a result, power efficiency is significantly improved.

In this embodiment, the drive transistor (6) (
7) The heat generation and fIM degree increase in (8) is large. The temperature of the drive transistor is detected by the temperature detector αυ, and when the detected temperature becomes larger than a predetermined value, the temperature detector αυ
The output 14 flows out and generates a voltage drop across the resistor of the current corrector section, reducing the current supplied to the coil (the current flowing through the drive transistor).

As a result, the amount of heat generated in the drive transistor is small, and excessive temperature rise and thermal breakdown are prevented.

Next, a description will be given of the transient operation leading to Tanabata speed control in this embodiment. When the motor is started and accelerated, the output A (V,) of the speed detector (6) is large,
The first feedback loop increases the current 1a supplied to the coil. The increase in Ia reduces the operating voltage of the drive transistor, so if the output 17 of the operation controller Q is large, the voltage drop v5 of the resistor (c) of the voltage converter (141) is increased.
increases, the on-time ratio of the switching transistor υ increases, and the output voltage M increases (operation of the second feedback loop).

When the motor movable part (magnet) (2)) is accelerated and its rotational speed reaches a predetermined value, the output A of the speed detector @
decreases, the current Ia to the coil becomes small, and the output voltage vM of the voltage converter α41 also becomes small.

Due to the pull-in of speed control (and phase control), the rotational speed of the movable part of the motor becomes transiently faster than the target rotational speed (overshoot). At this time, the output B of the speed detector (6) changes from Ov to ■8), the switch of the distribution selector (to) switches, and the output i of the current controller Q]J changes to the second selector. -, and distributes and controls the energization of the drive transistor (6) (7 bar 8) so as to generate deceleration (・, torque).The output B of the speed detector (2) is V
(when deceleration torque occurs), the motion controller μ
field transistor (132J and turn on the voltage converter a)
Increase the voltage of the resistor (c) 5, increase the on-time ratio of the switching transistor @p (including when the on state continues), and increase the output voltage VM of the voltage converter α to the maximum value or a predetermined value. It is regarded as a large value. In this way, when deceleration torque occurs, drive transistors (6) (7)
) If the output voltage vM of the voltage converter QX is increased regardless of the operating voltage in (8), when the generation of deceleration torque changes again to the generation of acceleration torque, the output Aff, ) of the speed detector @ will be Even if the voltage suddenly increases, the drive transistors (6), (7), and (8) can supply the current Ia corresponding to vl to the coil/L/(3/bar 4) (5) without being saturated. As a result, even if the response operation of the second feedback loop is slow, the pull-in settling of speed control (and phase control) can be easily and stably performed.

Also, when the output B of the speed detector (2) becomes v8 (when deceleration torque occurs), the transistor (2
10) becomes active, its output i4 becomes zero, and no current correction operation is performed. Therefore, the negative effects of control pull-in caused by heat generation and temperature rise when deceleration torque is generated during transient phenomena of motor startup and acceleration are prevented.

It should be noted that only in FIG. 3 1 are the drive transistors (7) (8) of the embodiment shown in FIG. If the main transistors and resistors are integrated on a single silicon chip, the mounting area becomes smaller and temperature detection and control operations become more stable.

Furthermore, the range in which the temperature detection and current correction operations described in ncI are prevented is not limited to only when deceleration torque occurs, but is partially limited to the range in which acceleration torque occurs (the small range of the command signal ■). ) may be included in the present invention.

Furthermore, the present invention is not limited to rotary motors that perform rotational motion;
It goes without saying that the same method can be applied to a so-called linear motor in which the field portion and the coil move linearly relative to each other. Further, the number of four coils is not limited to three phases, and in general, a motor having multiphase coils can be constructed. Furthermore, it is not only possible to supply current in one direction to the coil, but also to supply current in both directions by the drive transistor (
For example, the method described in Japanese Patent Publication No. 55-6938)
.

However, the configuration of the position detector is not limited to a magnetoelectric transducer such as a Hall element, and a method using high frequency coupling, for example, may be used. In addition, various modifications are possible without changing the gist of the present invention.

Effects of the Invention The motor of the present invention has a protective function that completely prevents thermal destruction of the drive transistor in the event of failure of the motor chain, etc., and can improve control pull-in and settling during speed control. Therefore, according to the invention, for example video
By configuring the data recorder's cab stan motor or cylinder motor, you can obtain a high-performance, highly reliable motor.

[Brief explanation of the drawing]

Figure 1 is an electrical circuit diagram showing some connections of the motor;
The figure is a technical diagram for explaining the operation, Figure 3 is an electric circuit diagram representing one embodiment of the present invention, Figure 4 is a diagram representing a specific configuration example of a speed detector, and Figure 5 is a current controller. FIG. 6 is a diagram showing a specific structure of a distribution switch, and FIG. 7 is an electric circuit diagram showing another embodiment of the present invention. (1)...DC power supply, (2)...Field magnet, (3) (4) (5)...Coil, (6) (
7) (8)...Drive transistor, (9)...Position detector, Detector...Distributor, (lυ...Temperature detector,
@...Speed detector, Lord...Movement controller, Q41...
・Voltage converter, C2〃(4) Threat...Hall element, thought...
...Current controller, (3→...Distribution switch, (g)...
・@1 selector, NG... 2nd selector, (2)...
-Current detector, (inquiry...current corrector, 4...oscillator, Q4...comparison, l81)...nutching transistor Yoshihiro Shirohata Kabumoto

Claims (1)

[Claims] 1. Position detection means for detecting the position of the motor movable part;
A plurality of phase coils, a drive transistor group for supplying current to the coil, a distribution means for controlling the entire energization distribution of the drive transistor group in response to the output of the position detection means, and accelerating current distribution to the coil. A switching mechanism for switching between generation of torque and generation of deceleration torque, a temperature detection means for detecting the entire temperature of the drive transistor, and a temperature detection means for detecting the entire temperature of the drive transistor, and a temperature detection means that responds to the output of the temperature detection means to ensure that the detected temperature is equal to or higher than a predetermined value. If the deceleration torque is generated by the current correction means for correcting the current supplied to the coil and the distribution switching means, the current correction means for correcting the current supplied to the coil even if the detected temperature is above a predetermined value. Hand that prevents the current correction operation of J9
E-equipped motor. 2. Position detection means for detecting the position of the motor movable part;
a plurality of phase coils, a group of drive transistors that supply current to the coils, a distribution device that distributes and controls energization of the group of drive transistors in response to the output of the position detection device, and a variable output DC voltage from a DC power supply. a switching type voltage conversion means for obtaining the voltage of the coil; distribution switching means for switching current distribution between generation of acceleration torque and generation of deceleration torque; temperature detection means for detecting the temperature of the drive transistor; and a predetermined detection temperature in response to the output of the temperature detection means. If the current correction means corrects the current supplied to the coil when the current exceeds a value, and the distribution switching means generates a deceleration torque, the output voltage of the voltage conversion means is set to a predetermined value or a maximum value, and A motor comprising means for preventing the current correction operation even if the detected temperature is equal to or higher than the predetermined value.