JPH0456556B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic commutator type electric motor, and particularly to one that efficiently utilizes electric power supplied from a power source.

Conventionally, in an electronic commutator type current machine, a transistor or the like is used to reduce and control the voltage from a DC power source with a constant output voltage, and supply a driving voltage corresponding to, for example, the speed of a motor.

FIG. 1 shows an example of the configuration of a conventional electronic commutator type motor. In FIG. 1, 1 is a DC power supply, 2 is a current controller, 3, 4, and 5 are drive transistors, 6,
7 and 8 are three-phase coils, and 9 is a field magnet attached to the rotor.

The energization controller 2 switches the driving transistor to be energized according to the rotation of the magnet 9, and also applies a voltage to the coils 6, 7, 8 according to the rotational speed.
supply to. Therefore, the voltage of the DC power supply 1 is dividedly applied to the drive transistors 3, 4, 5 and the coils 6, 7, 8. As a result, the power supplied by the DC power supply 1 is the sum of the effective power consumption in the coil and the collector loss of the drive transistor.

In a normal electric motor, the collector loss of the drive transistor is quite large, and the ratio of effective power consumption to power supplied by the power supply (power efficiency) is small.
It was around 10% to 30%. In particular, electric motors with a wide variable speed range, such as multi-speed switching, and electric motors with a wide variable drive force, such as winding motors, tend to have significantly lower efficiency when operating at low speeds and low driving forces. Ta.

In addition, in the configuration shown in FIG. 1, the coil 6,
Since current flows only in one direction through the coils 7 and 8, the coil utilization rate is low and the motor efficiency is even lower.

Taking these points into consideration, the present invention provides a power-efficient electronic commutator that uses switching-type voltage conversion means that can supply current to the coil in both directions and extract a variable output DC voltage. The purpose of the present invention is to provide a type of electric motor that is particularly suitable for variable speed electric devices, variable driving force electric devices, etc., and has excellent power efficiency during low speed operation and low driving force operation. That's what you're trying to get.

That is, the present invention includes a position detection means for detecting the position of a movable part of a motor, a multi-phase coil, a switching type voltage conversion means for obtaining a variable output DC voltage from a DC power supply, and one of the voltage conversion means. A first drive transistor group consisting of K first drive transistors (K is an integer of 3 or more) connected between an output terminal and each power supply terminal of the coil, and commands current supply to the coil. first distribution control means that distributes and controls energization of the first drive transistor group in response to a command signal and in response to the output of the position detection means; the other output terminal of the voltage conversion means; a second drive transistor group consisting of K second drive transistors connected between each of the power supply terminals of the coil; and energization of the second drive transistor group in response to an output of the position detection means. The second distribution control means includes a second distribution control means that performs distribution control, and an operation detection control means that controls the output voltage of the voltage conversion means, and the second distribution control means is provided with a first reference voltage signal that obtains a first reference voltage signal. Voltage generation means compares the operating voltage of the first drive transistor in the energized state of the first drive transistor group with the first reference voltage signal, and according to the comparison output, the second drive transistor The operation detection control means includes a second reference voltage generation means for obtaining a second reference voltage signal, and a second reference voltage generation means for obtaining a second reference voltage signal, and the second drive transistor group. and a second comparing means for comparing the operating voltage of the second driving transistor in the energized state with the second reference voltage signal and controlling the output voltage of the voltage converting means according to the comparison output. further configured to change the first reference voltage signal of the first reference voltage generating means and the second reference voltage signal of the second reference voltage generating means in response to the command signal. It is characterized by the fact that

The present invention will be explained below based on illustrated embodiments. FIG. 2 is a circuit diagram showing one embodiment of the present invention. In Fig. 2, 1 is a DC power supply;
3, 4, 5 are first drive transistors; 6, 7,
8 is a three-phase coil, 9 is a field magnet, and a portion 11 surrounded by a broken line is a Hall element 41, 42, 43, 44, which senses the magnetic flux of the magnet 9.
45 and 46, a position detector detects the rotational position of the magnet 9 (motor movable part); 12 controls distribution of energization of the first drive transistors 3, 4, and 5 in response to the output of the position detector 11; The first distribution controller 13, 14, 15 is the coil 6, 7, 8
and the first drive transistors 3, 4, and 5 (each input terminal is connected to the power supply side, and each output terminal is connected to each output terminal of the first drive transistors 3, 4, and 5). A second drive transistor 16 (connected) is responsive to the output of the position detector 11 to
a second distribution controller that distributes and controls the energization of 5;
is inserted in series in the current path from the DC power source 1 to the coils 6, 7, and 8, and is a switching type voltage converter 18 that obtains a variable output DC voltage from the DC power source 1;
is an operation detection controller that detects the operating voltage of the second drive transistors 13, 14, and 15 when they are energized, and controls the output voltage of the voltage converter 17 based on the detection signal. Further, 21 and 22 are DC voltage sources, 23
is the command signal, 24 is the current corresponding to the command signal 23
A current converter that outputs i ₁ , 19 is a current converter 24
This is a similar current generator that generates currents i ₂ , i ₃ , and i ₄ in response to the output current i ₁ of .

Next, its operation will be explained. Command signal 2
3 is input to the current converter 24, compared with the voltage value of the power source 22, and converted into a current i ₁ according to the difference between the two. The command signal 23 is obtained by well-known speed detection means and speed/voltage conversion means, and changes its value in accordance with the rotational speed of the magnet 9.

FIG. 3 shows a specific example of the configuration of the current converter 24. The command signal 23 and the voltage source 22 are applied to the paces of the differential transistors 111 and 112, respectively,
The current value of the constant current source 115 is distributed to each collector side according to the voltage difference. The collector current of transistor 111 is inverted by a current mirror made up of transistors 116 and 117, compared with the collector current of transistor 112, and output (current absorption) via transistor 118.

The output i ₁ of the current converter 24 is the analog current generator 19
is input. Similar current generator 19 includes transistors 25, 26, 27, 28, 29 and resistors 30, 3.
A first current mirror consisting of 1, 32, and 33, a diode 34, a transistor 35, and a resistor 3
6 and 37, and outputs currents i ₂ , i ₃ , i ₄ that are similar (proportional or approximately proportional) to the output i ₁ of the current converter 24 . current i ₂
is converted into a voltage signal V ₁ by the diode 54 and resistor 55 of the first distribution controller 12, and the current i ₃ is
The resistor 61 of the distribution controller 16, the diode 62,
63 into a voltage signal _V2 , and the current _i4 is passed through the diodes 81, 82 and the resistor 8 of the operation detection controller 18.
3 into a voltage signal _V3 . These voltages V ₁ , V ₂ , and V ₃ change in response to the command signal 23 (change in conjunction with each other).

First, the normal rotation drive operation will be explained.
Here, consider V _M to be constant. First distribution controller 1
2 is inserted in series in the current path to the coils 6, 7, 8 (the current path for the first drive transistors 3, 4, 5), and includes a current detection resistor 47 for detecting the supplied current, and a resistor. 47 voltage drop and command signal 23
The current controller 48 receives a voltage signal V ₁ responsive to the voltage signal V 1 and obtains an output current responsive to both signals, and a first selector 53 comprising transistors 50 , 51 , and 52 .

FIG. 4 shows a specific example of the configuration of the current controller 48. A voltage signal is applied to the base side of the transistor 121.
V ₁ is input, the voltage drop signal of the resistor 47 is input to the emitter side, a collector current responsive to the difference between the two is obtained, the current is inverted by the current mirror of transistors 122 and 123, and is output. 1
is supplied to the selector 53.

Transistors 50, 51 of the first selector 53,
The emitters 52 are commonly connected, and the output voltages of the Hall elements 41, 42, and 43 of the position detector 11 are applied to the base side, respectively. Hall element 4
1, 42, 43 sense the magnetic flux of magnet 9,
An analog voltage signal is generated according to the rotational position. The common emitter current of the transistors 50, 51, and 52 is divided into collector currents 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 zero. Become. The collector currents of the transistors 50, 51, 52 become the base currents of the first drive transistors 3, 4, 5, are amplified and supplied to the coils 6, 7, 8.

The current supplied to the coils 6 , 7 , 8 (the current flowing through the drive transistors 3 , 4 , 5 ) is detected as a voltage drop across the resistor 47 and is input to the current controller 48 . As a result, a first feedback loop (current feedback loop) is configured by the current controller 48, the first selector 53, the first drive transistors 3, 4, 5, and the resistor 47, and the coils 6, 7, 8 to ensure that the voltage signal V ₁ (and therefore the command signal 23)
The current value corresponds to As a result, the first
The influence of _hFE variations in the drive transistors 3, 4, and 5 is significantly reduced. Further, the currents of the first drive transistors 3, 4, 5 are controlled so that the output voltages of the Hall elements 41, 42, 43 change with the rotation of the magnet 9, and currents are supplied to the corresponding coils. Switching.

Note that the capacitor 49 is provided for phase compensation of the feedback loop described above. In addition, a capacitor 94 connected in parallel to the coils 6, 7, and 8,
The series circuit of resistors 96, 98 and resistors 95, 97, and 99 reduces the spike voltage caused by switching of the energizing path.

The second distribution controller 16 controls the operating voltage (collector
Detection to detect the absolute value of the emitter voltage V _CE
It is composed of a comparator 71 and a second selector 76 made up of transistors 73, 74, and 75.

The output _i3 of the similar current generator 19 is the detector/comparator 7.
1, resistor 61, diodes 62, 63
As a result, a reference voltage signal V ₂ of a predetermined voltage value is generated from the common connection terminal (emitter side) of the first drive transistors 3, 4, and 5. Voltage signal V ₂ is a voltage signal
It changes in conjunction with V ₁ (both V ₁ and V ₂ are command signal 2).
3), when the supply current to the coils 6, 7, 8 (i.e., the conduction current of the first drive transistors 3, 4, 5) is large, the signal V ₂ is made large, and when the supply current is small. Sometimes the signal _V2 is made small.

Each emitter side of the detection transistors 64, 65, and 66 serves as an input terminal at a reference potential point (signal V ₂ point).
(directly or via a resistor, diode, etc.), and each base side is connected to each output terminal of the first drive transistors 3, 4, and 5 as a detection terminal. As a result, the operating voltage of the first drive transistors 3, 4, and ₅ in the energized state is compared with the reference voltage signal _V2 , and the operating voltage value is higher than the emitter-base forward voltage. When the voltage decreases by V _D , the corresponding detection transistor becomes conductive and outputs a current to the collector side.

FIG. 5 shows the current path when drive transistors 13 and 4 are activated. The signal path is the output V _M of the voltage converter 17 → the second drive transistor 13 → the coils 6 and 7 → the first drive transistor 4 → the resistor 47 → the side power supply, and the first drive transistor 4 in the energized state Operating voltage V _CE is different from other drive transistors 3, 5
The voltage V will be smaller than _CE . Then, the detection transistors 64, 65, and 66 compare the voltage V _CE of the first drive transistors 3, 4, and 5 with the reference voltage signal V ₂ and output a collector current according to the difference. In FIG. 5, when the operating voltage of the first drive transistor 4 becomes smaller than the voltage signal V ₂ by the base-emitter forward voltage V _D , the detection transistor 65 becomes active and outputs a collector current. The output currents of each detection transistor 64, 65, 66 are combined (collectors are connected in common), and a diode 67, a transistor 69, and a resistor 68, 7
The signal is inverted and amplified by a current mirror consisting of 0, and is supplied to the second selector 76. Therefore, an output current corresponding to the operating voltage of the first drive transistor when energized is obtained.

Transistors 73, 74 of the second selector 76,
The emitters 75 are commonly connected, the outputs of the Hall elements 44, 45, and 46 of the position detector 11 are applied to each base terminal, and the common emitter current is distributed to the collector side according to the base voltage. The collector currents of the transistors 73, 74, and 75 become the base currents of the second drive transistors 13, 14, and 15, and switch and control the energization of the coils 6, 7, and 8.

Therefore, the detection/comparator 71 and the second selector 7
6, second drive transistors 13, 14, 15,
A second feedback loop is constituted by the coils 6, 7, and 8, and the operating voltage _VCE of the first drive transistors 3, 4, and 5 in the energized state is set to a predetermined small voltage value within the active region. A current equal to the current flowing through the first drive transistors 3, 4, 5 (corresponding to the command signal 23) also flows through the second drive transistors 13, 14, 15, and the coils 6, 7, A bidirectional current (a current whose direction changes as the magnet 9 rotates) is stably supplied to the magnet 8.

To explain this, when the current flowing through the second drive transistor transiently becomes smaller than the current flowing through the first drive transistor, the operating voltage of the first drive transistor decreases due to the load effect of the coil. This decrease in the operating voltage is detected by the detector/comparator 71 and increases the base current and thus the collector current of the second drive transistor via the second selector 76, so that the voltage of the first drive transistor increases. A current equal to the current flowing current (collector current) is output from the second drive transistor.
In addition, the operating voltage of the first drive transistor is a _small value (approximately
(equal to V ₂ − V _D ). Note that the capacitor 77 is provided for phase compensation (to prevent oscillation) of the second feedback loop.

In this way, the first feedback loop and the second feedback loop stably supply the current corresponding to the command signal 23 to the coil corresponding to the output of the position detector 11, and as the magnet 9 rotates, the current is stably supplied to the coil corresponding to the output of the position detector 11. coil 6,
The current paths to 7 and 8 are switched sequentially, and current is supplied in both directions.

Next, a method of controlling the output voltage V _M by the operation detection controller 18 and the voltage converter 17 will be explained.
The output i ₄ of the similar current generator 19 is the operation detection controller 1
8, diodes 81, 82, resistor 83
The second drive transistor 13, 14, 1
A reference voltage signal ₃ of a predetermined voltage value is generated from the common connection terminal (emitter side) of 5. The voltage signal ₃ changes in conjunction with the voltage signal V ₁ (both V ₁ and V _{3 change in response to the command signal 23), and the voltage signal 3 changes in conjunction with the voltage signal V 1 (both V 1 and V 3} change in response to the command signal 23), and the voltage signal 3 changes in conjunction with the voltage signal V 1 (both V 1 and V 3 change in response to the command signal 23). The signal V ₃ is made large when the supply current (current flowing through the drive transistor No. ₂ ) is large, and is made small when the supply current is small. Detection transistors 87, 88, 89
Each base side of the
V ₃ point), and each emitter side is connected to the second drive transistor 13, 1 via resistors 84, 85, 86, respectively, as a detection terminal.
It is connected to each output terminal No. 4 and No. 15. As a result, the operating voltage (absolute value of collector-emitter voltage drop) of the second drive transistors 13, 14, and 15 in the energized state is compared with the reference voltage signal _V3 , and the operating voltage value is determined by the signal V3. When the emitter-base forward voltage V _D becomes smaller than V ₃ , the corresponding detection transistors 87, 88,
89 becomes conductive and outputs current to the collector side.

For example, as shown in FIG.
When transistors 3 and 4 are activated, the operating voltage of the second drive transistor 13 in the energized state is lower than the voltage of the other drive transistors 14 and 15. The detection transistors 87, 88, 89 compare the operating voltages of the second drive transistors 13, 14, 15 with the reference voltage signal _V3 , and in FIG. ₃ by V _D , the detection transistor 87 becomes active and outputs a collector current. The output currents of each detection transistor 87, 88, 89 are combined (collectors are connected in common), and a diode 90, a transistor 91, a resistor 92, 93
is inverted and amplified by a current mirror consisting of
It is supplied to a voltage converter 17. Therefore, an output current can be obtained that corresponds to the operating voltage of the second drive transistors 13, 14, 15 when energized.

The voltage converter 17 is a switching transistor that constitutes a semiconductor switch element for power supply control inserted in series in the power supply path from the positive terminal (V _S = 20V) of the DC power supply 1 to the coils 6, 7, and 8. 101 and its bias resistors 102 and 10
3, a switching controller 10 that controls on/off the switching transistor 101, a flywheel diode 105, an inductance element 106, and a capacitor 107. The switching controller 100 can utilize various well-known configurations, such as a triangular wave generator that generates a triangular voltage signal of 50 KPH, and a comparator that converts the output of the operation detection controller 18 into a voltage signal and then compares it with the triangular wave signal. , a duty pulse signal corresponding to the output signal of the operation detection controller 18 is obtained, and the switching transistor 101 is controlled on/off. Output voltage of voltage converter 17
V _M changes in relation to the on time and off time (substantive duty ratio) of the switching transistor 101. When this switching transistor 101 is on, ViV _S is established, and the DC power supply 1 supplies current to the load side through the inductance element 106. switching transistor 10
1 turns off, flywheel diode 105 turns on and inductance element 106
The energy stored in is supplied to the load side. As a result, the output voltage V _M of the voltage converter 17 has a value corresponding to the duty (on time ratio) of the on time of the transistor 101.

The output current of the operation detection controller 18 is the voltage converter 1.
7, when the current value increases, the on-time ratio of the switching transistor 101 is increased to increase the output voltage _VM , and when the current value decreases, the on-time ratio is decreased to decrease the output voltage _VM . Therefore, the motion detection controller 18, the voltage converter 17 and the second drive transistor 13,1
4 and 15 constitute a third feedback loop,
The aforementioned second drive transistors 13, 14, 15
The output voltage V _M of the voltage converter 17 is adjusted so that the operating voltage when energized is detected, and the operating voltage is a predetermined value corresponding to the reference voltage signal V ₃ (about V ₃ −V _D ).
is under control. To explain this, the second
When the operating voltage of the drive transistors 13, 14, and 15 decreases, the output current of the operation detection controller 18 increases, and the on-time ratio of the switching transistor 101 is increased by the operation of the switching controller 10, and the voltage converter The output voltage V _M of No. 17 is increased to increase the operating voltage of the second drive transistor. The same applies to the reverse case.

Next, the overall operation of the first, second and third feedback loops will be explained. Now, assuming that the feedback loop is in a balanced state, the voltage drop across the resistor 47 will be a value corresponding to the command signal 23, and the voltage drop across the first drive transistor 3, 4, 5 and the second drive transistor 13, 14, 15 will be a value corresponding to the command signal 23. supplies a current corresponding to the command signal 23 to the coil selected by the position detector 11 (first and second feedback loops),
The operating voltage of the first drive transistors 3, 4, 5 in the energized state is equal to the voltage signal V ₂ (therefore,
The operating voltage of the transistors in the energized state of the second drive transistors 13, 14, 15 becomes a predetermined small value in the active region corresponding to the command signal _V3 (second feedback loop). Then,
This becomes a predetermined small value within the active region corresponding to the command signal 23) (third feedback loop). That is,
The voltage V _S of the DC power supply 1 is applied to each part of the circuit as shown in FIG.

Let us consider a case where the command signal 23 becomes slightly smaller from such a state.

The decrease in the command signal 23 is the output of the current converter 24.
By increasing i ₁ , the output current of the similar current generator 19
By increasing the values of i ₂ , i ₃ , i ₄ , the voltage signals V ₁ , V ₂ ,
Increase V ₃ .

As the voltage signal V ₁ increases, the base current and thus the collector current of the energized first drive transistors 3, 4, 5 increases (first feedback loop), and their operating voltage decreases (the (The current flowing through the drive transistor becomes larger than the current flowing through the second drive transistor.)

The increase in the voltage signal V ₂ and the decrease in the operating voltage of the first drive transistor are caused by the second distribution controller 1
The output current of the detection/comparator 71 of No. 6 is increased, and the base current of the second drive transistors 13, 14, 15 in the energized state, and hence the collector current becomes larger (second feedback loop).
The current flowing through the second driving transistor becomes equal to the current flowing through the first driving transistor and becomes stable. Furthermore, the operating voltage of the first drive transistor is a predetermined value that is convective with the voltage signal _V2 .

Due to the operation of the first and second feedback loops, the power supplied to the coils 6, 7, and 8 increases and the voltage drop increases, so the operating voltage of the second drive transistor decreases (the voltage of the first drive transistor decreases). The operating voltage is determined by the second feedback loop).

When the second drive transistors 13, 14, 15 are energized, a decrease in the operating voltage of the transistors and an increase in the voltage signal _V3 are detected by the operation detection controller 18, and the output current is increased, and the voltage converter 17 The on-time ratio of the switching transistor 101 is increased to increase its output voltage V _M (third feedback loop). the result,
The operating voltage of the second drive transistor is set as a voltage signal.
Output voltage to a given value corresponding to V ₃
V _M is generated and stabilized (the whole becomes stable).

Even when the command signal 23 changes significantly, it settles into a similar stable state (the above-mentioned minute changes may be considered to occur continuously).

The electric motor of this embodiment has greatly improved efficiency in the following points.

(1) Since current flows through the coil in both directions, the utilization rate of the coil is high.

(2) The operating voltage of the first drive transistor and the second drive transistor is a predetermined small value within the active region, and the collector loss thereof is small (due to the operation of the second feedback loop and the third feedback loop). .

(3) Since a switching type voltage converter is used, the loss associated with voltage conversion is extremely small.

In addition, the operation of the first feedback loop ensures that the current supplied to the coil is at a value corresponding to the command signal, and the operating voltage when the first drive transistor is energized and the operating voltage when the second drive transistor is energized are as follows. Variations in operating voltage between phases are reduced, making detection easier and more stable.

Furthermore, in this embodiment, the input terminal side is DC-connected (directly or via a resistor, diode, etc.) to the potential point of the reference voltage signal _V2 or _V3 , and the detection terminal side is DC-connected to the drive transistor 3. , 4, 5 or 13, 14, 15.
Since the detection transistors 64, 65, 66, 87, 88, 89 made of PNP type transistors are used, the first drive transistors 3, 4, 5
or second drive transistor 13, 14, 15
The only elements required to detect the operating voltage of the device are transistors, diodes, and resistors, which can be integrated on a single silicon chip.

As a result, when the circuit portion of the electric motor shown in FIG. 2 is constructed from a monolithic integrated circuit, the number of external parts is reduced and manufacturing is facilitated. In addition, the detection characteristics have small variations between phases, and the current required for detection can be small. Furthermore, if a PNP transistor with a lateral structure is used as the detection transistor, the base-emitter breakdown voltage and the base-collector breakdown voltage can be increased, improving reliability.

Further, in this embodiment, the reference voltage signal to be compared with the operating voltage of the first drive transistors 3, 4, and 5 is
V ₂ or second drive transistor 13, 14,
A reference voltage signal V ₃ to be compared with the operating voltage of coil 15 is changed in response to command signal 23, and coils 6, 7,
When the supply current to 8 (that is, the current flowing through the drive transistor) is large, the voltages V ₂ and V ₃ are increased,
When the supply current is small, the voltages V ₂ and V ₃ are made small. As a result, the voltage converter 1 ensures that the operating voltage of the drive transistor is a small voltage value within the active region, regardless of the magnitude of the current flowing through it.
The output voltage of No. 7 and the conduction current of the second drive transistor are controlled. These characteristics are especially
This is important when considering the saturation of the drive transistor.

In this regard, the second drive transistor 13,
The control of the operating voltages 14 and 15 (third feedback loop) will be explained as an example. Generally, the saturation voltage of a transistor increases in proportion to the conducting current (collector current), and conversely, the active region becomes narrower (see FIG. 7).

Now, consider the case where the voltage signal V ₄ is constant (the voltages across the resistor 81 and diodes 82 and 83 are constant). If the second drive transistor is in a saturated state and operates to increase the current flowing through it, the operating voltage (in this case, the saturation voltage) increases as the current flowing therein increases. Therefore, the difference between the reference voltage signal V ₃ and the operating voltage becomes smaller, the output current of the detection transistor becomes smaller, and the voltage converter 1
Decrease the rotational voltage V _M of No. 7. As a result, even though there is still sufficient margin in the output range of the voltage converter 17, the output current of the operation detection controller 18 is small, so the voltage V _M becomes stable at a small value (third feedback). loop malfunction).

On the other hand, if the voltage signal V ₃ is changed in response to the energizing current as in this embodiment, the increase in the voltage signal V ₃ can be larger than the increase in the saturation voltage of the drive transistor as the energizing current increases. To,
The detection transistor is fully forward biased and
The output current of the motion detection controller 18 increases, and the output voltage V _M of the voltage converter 17 also increases to the maximum value of the output range. That is, regardless of the current supplied to the coil, as long as the output of the voltage converter 17 is within the response range, the third feedback loop operates reliably. Furthermore, since the operating voltage of the drive transistor can be set low when the current supplied to the coil is small, the collector loss can be significantly reduced.

The above description is based on the second distribution controller 16 and the second drive transistors 13, 14, 15.
This also applies to the operation of the detector/comparator that detects the operating voltage of the first drive transistors 3, 4, ₅ in the operation of the feedback loop of It is preferable that the current is changed in conjunction with the applied current.

However, the present invention is not limited to such a case, and one or both of the reference voltage signals V ₂ and V ₃ may be kept constant. FIG. 8 shows a circuit connection diagram representing another embodiment of the present invention in which the signals V ₂ and V ₃ are kept constant. In this example, the current of the constant current source 201 is supplied to the resistor 61 and the diodes 62 and 63, and V ₂
is constant, and the current of the constant current source 202 is connected to the resistor 8.
3. _V3 is kept constant by supplying it to diodes 81 and 82. In such a case, it is necessary to set the reference voltages V ₂ and V ₃ large in order to prevent the aforementioned second and third feedback loops from malfunctioning.
As a result, drive transistors 3, 4, 5 and 1
The collector losses at points 3, 14, and 15 are larger than in the embodiment shown in FIG.

Furthermore, in the configuration of the operation detection controller 18 shown in the embodiment of FIG. 2 or _{FIG .}
If it becomes larger than this, the output current becomes constant (zero) and does not change. Then, when the operating voltage becomes less than a predetermined value (V ₃ −V _D ), the output current changes in response to the operating voltage. FIG. 9 shows its characteristics. If this characteristic is used, when the operating voltage of the second drive transistor decreases and saturates, a current corresponding to (proportional to) the difference between the operating voltage (saturation voltage) and the reference voltage _V3 will be output. Therefore, the deeper the saturation, the larger the output current becomes, and the response operation of the third feedback loop becomes stable and reliable. Further, the response range of the motion detection controller 18 may be narrow, and the configuration can be simplified. Note that when the operating voltage of the second drive transistor is sufficiently higher than V ₃ −V _D , the output current of the operation detection controller 18 is transiently constant (zero), but the output current of the third feedback loop is As a result of the operation, the output voltage of the voltage converter becomes smaller, and the output current of the operation detection controller 18 becomes stable in a region that responds to the operation voltage.

Similarly, the characteristics of the detection/comparator 71 of the second divider 16 are as shown in FIG. 9, and the second feedback loop when the first drive transistor passes a large current and becomes saturated. The operation of the detector/comparator 71 is made stable and reliable, and the response range of the detector/comparator 71 is narrowed to simplify the configuration.

As in the above embodiment, the first and second drive transistors supply current to the coil in both directions, and the switching voltage converter adjusts the operating voltage of the drive transistor to a predetermined small value within the active region. By configuring an electronic commutator type motor that maintains

(1) Improved coil utilization and improved efficiency.

(2) Extremely high power efficiency.

(3) The rated power of the drive transistor becomes smaller.

(4) Less heat is generated in the drive transistor and voltage converter.

(5) Switching noise associated with voltage conversion does not occur in the coil.

(6) Commutator (brush) noise does not occur.

(7) Shielding against noise is simple, requiring only the voltage converter.

In particular, the configuration of the embodiment shown in FIG. 2 has the following great advantages.

(a) By wiring only the power supply terminals that supply current to the multiphase coils, we have realized a drive system that stably and reliably supplies current in both directions in response to command signals. Therefore, it is not necessary to connect the common connection terminals of the coils, and the number of connection terminals to the coils of the motor may be small.

(b) Since the operating voltage of the first drive transistor and the second drive transistor when the current supplied to the coil is small can be significantly reduced, the operating voltage of the first drive transistor and the second drive transistor when the current is supplied to the coil is small. Power loss can be significantly reduced. Therefore, power efficiency is improved. In particular, since the supplied current is considerably small during steady speed control, a significant efficiency improvement can be achieved.

(c) Since the operating voltage of the first drive transistor and the second drive transistor can be increased when the current supplied to the coil is large, the first drive transistor and the second drive transistor are stable even when a large current is supplied. Operates in the active region. Therefore, the operating voltage of the drive transistor is stably controlled regardless of the value and fluctuation of the coil current.

It goes without saying that the present invention is not limited to a rotary electric motor that rotates, but can be similarly applied to a so-called linear electric motor in which a movable part of the motor moves relative to each other in a straight line. Furthermore, it is not limited to stable field means using magnets, but any field means with fixed magnetization may be used. For example, even a magnetic pole structure that is excited by direct current can be used. The number of phases is also not limited to three, but may be arbitrary.

Further, although the operation detection controller 18 in the above-described embodiment is configured to detect all the operating voltages when the second drive transistors 13, 14, and 15 are energized, the present invention is not limited to such a case. The operating voltage of at least one drive transistor may be detected when it is energized.

Further, the position detecting means is not limited to the magneto-electric transducer such as the Hall element shown in the above-mentioned embodiments, and various known methods such as a method using high frequency coupling can be used.

In addition, drive transistors 3, 4, 5, 13, 1
The switching transistors 4 and 15 are not limited to bipolar transistors, but may also be field effect transistors, and the switching transistor 101 is not limited to bipolar transistors, but can also be semiconductor elements such as field effect transistors or thyristors.

Furthermore, in the above-mentioned embodiment, the output voltage of the voltage converter is lower than the DC power source, but the present invention is not limited to such a case. It may also be supplied to Further, the configuration of the voltage converter is not limited to the above-described embodiment, and various methods and configurations such as an inverter type, a frequency modulation type chipper type, and a pulse width modulation type chipper type can be adopted. In addition, various modifications are possible based on the gist of the present invention.

As is clear from the above description, the electric motor of the present invention has the advantage of significantly improved power efficiency.
Therefore, if an electronic commutator type motor for use in audio/visual equipment, for example, is configured based on the present invention, it can be made into a power-saving device with extremely low power consumption.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a conventional electric motor, Fig. 2 is a circuit connection diagram representing an embodiment of the present invention, Fig. 3 is a diagram showing a specific configuration example of a current converter, and Fig. 4 is a diagram of a current controller. 5 is a diagram for explaining the circuit operation of FIG. 2, FIG. 6 is a diagram showing the voltage distribution in each part of the circuit of FIG. 2, and FIG. 7 is a diagram showing the operating area of the transistor. FIG. 8 is a circuit diagram showing another embodiment of the present invention, and FIG. 9 is a characteristic diagram of the operation detection controller or the detection/comparator. DESCRIPTION OF SYMBOLS 1... DC power supply, 3, 4, 5... 1st drive transistor, 6, 7, 8... Coil, 9... Magnet,
11...position detector, 12...first distribution controller, 1
3, 14, 15...second drive transistor, 16
...Second distribution controller, 17...Voltage converter, 18...
Operation detection controller, 19... Similar current generator, 23...
Command signal, 24...Current converter, 41, 42, 4
3, 44, 45, 46... Hall element, 48... Current controller, 53... First selector, 64, 65, 6
6, 87, 88, 89...detection transistor, 71
...Detector/comparator, 76...Second selector, 109...
Switching controller, 101... switching transistor.

Claims (1)

[Claims] 1. A position detection means for detecting the position of a motor movable part, a multi-phase coil, a switching type voltage conversion means for obtaining a variable output DC voltage from a DC power supply, one output terminal of the voltage conversion means and the coil. K (K is 3) connected between each power supply terminal of
a first drive transistor group consisting of first drive transistors (an integer greater than or equal to); a first distribution control means for distributing and controlling energization of a group of drive transistors;
a second drive transistor group consisting of a second drive transistor; a second distribution control means for distributing and controlling energization of the second drive transistor group in response to the output of the position detection means; The second distribution control means includes a first reference voltage generation means for obtaining a first reference voltage signal, and an operation detection means for controlling the output voltage of the conversion means.
The first drive transistor group is in an energized state.
The operating voltage of the drive transistor of the first reference voltage signal is compared with the first reference voltage signal, and the second reference voltage signal is
the operation detection control means includes a second reference voltage generation means for obtaining a second reference voltage signal; Comparing the operating voltage of the second drive transistor in the energized state of the drive transistor group with the second reference voltage signal,
The second comparison means controls the output voltage of the voltage conversion means according to the comparison output, and further includes a second comparison means that controls the output voltage of the first reference voltage generation means and the second reference voltage signal of the first reference voltage generation means. An electric motor characterized in that the second reference voltage signal of the reference voltage generating means is configured to be changed in response to the command signal.