JPH036751B2 - - 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 motor, a transistor or the like is used to perform pressure reduction control from a DC power source with a constant output voltage, and supply a driving voltage corresponding to the speed of the motor, for example.

FIG. 1 shows an example of the configuration of a conventional electronic commutator type motor. In FIG. 1, 1 is a DC power source, 2 is a power supply 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 drive transistors to be energized in accordance with the rotation of the magnet 9, and supplies voltages to the coils 6, 7, and 8 in accordance with the rotational speed. Therefore, the voltage of the DC power supply 1 is the same as that of the drive transistors 3,
4 and 5 and coils 6, 7, and 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. In particular, the present invention is 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. The aim is to obtain a new electric motor.

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 generating means compares the operating voltage of the second drive transistor in the energized state of the second 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 first drive transistor group. and a second comparing means for comparing the operating voltage of the first 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. 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 to the
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 first drive transistors 3, 4, and 5 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 a command signal, 24 is a current converter that outputs a current i ₁ corresponding to the command signal 23, and 19 is a current i _{2 that responds to the output current i 1} of the current converter _24. , i ₃ , i ₄ .

Next, its operation will be explained. Command signal 2
3 is input to the current converter 24, compared with the voltage value of the voltage source 22, and converted into a current i ₁ according to the difference between the two. The command signal 23 is obtained by 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 bases 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 of transistors 116 and 117, compared with the collector current of transistor 112, and output (current sinked) through transistor 118.

The output i ₁ of the current converter 24 is input to the analogous current generator 19 . Similar current generator 19 includes transistors 25, 26, 27, 28, 29 and resistors 30, 3.
A first current mirror consisting of 1, 32, 33, a diode 34, a transistor 35, a resistor 36,
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 . The current i ₂ is passed through the diode 54 and resistor 55 of the first distribution controller 12.
The current i ₃ is converted into a voltage signal V ₁ by
The current i ₄ is converted into a voltage signal V ₂ by the resistor 61 and diodes 62 and ₆₃ of the operation detection controller 18 . This voltage V ₁ ,
V ₂ and V ₃ change in response to the command signal 23 (change in conjunction with each other). First, the normal rotational drive operation will be explained. Here, consider _VM 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, as the magnet 9 rotates, the output voltages of the Hall elements 41, 42, 43 change, and the energization of the first drive transistors 3, 4, 5 is controlled so that current is supplied to the corresponding coil, 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 includes a detection/comparator 71 that detects the operating voltage (absolute value of the collector-emitter voltage V _CE ) when the second drive transistors 13 , 14 , 15 are energized; 74,
A second selector 76 consisting of 75 is configured.

The output _i3 of the similar current generator 19 is the detector/comparator 7.
1, diodes 81, 82, resistor 83
The second drive transistor 13, 14, 1
A reference voltage signal V ₂ of a predetermined voltage value is generated from the common connection terminal (emitter side) of No. 5. The voltage signal V ₂ changes in conjunction with the voltage signal V ₁ (both V ₁ and V ₂ change in response to the command signal 23), and the coils 6, 7,
When the supply current to 8 (i.e., the current flowing through the first drive transistors 3, 4, 5) is large, the signal V ₂
is made large, and the signal _V2 is made small when the supply current is small.

The base sides of each of the detection transistors 87, 88, and 89 are connected as input terminals to the reference potential (signal _V2 point) in a direct current manner (directly or via a resistor, diode, etc.), and the emitter sides of each are connected as detection terminals. It is connected to each output terminal of the second drive transistors 13, 14, 15 via resistors 84, 85, 86. As a result, the operating voltage of the second drive transistors 13, 14, 15 in the energized state and the reference voltage signal _V2 are compared,
When the operating voltage value becomes smaller than the signal V ₂ by the emitter-base forward voltage 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. This current 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 second drive transistor 13 in the energized state The operating voltage V _CE is the other drive transistor 1
The voltage V _CE of 4 and 15 becomes smaller. and,
The detection transistors 87, 88, 89 compare the voltage V _CE of the second drive transistors 13, 14, 15 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 second drive transistor 13 becomes smaller than the voltage signal V ₂ by the base-emitter forward voltage V _D , the detection transistor 87 becomes active and outputs a collector current. Each detection transistor 8
The output currents of transistors 7, 88, and 89 are combined (collector sides are commonly connected), converted into a voltage by a diode 90 and a resistor 91, and applied to the base of a transistor 92. Furthermore, a predetermined voltage signal is applied to the base of the transistor 93 by resistors 95 and 97 and a diode 96. transistor 9
The current value of the constant current source 94 is distributed to the collector currents of the transistors 92 and 93 according to the base voltage difference between the transistors 2 and 93, and the collector current of the transistor 93 becomes large when the output currents of the detection transistors 87, 88, and 89 are small. , becomes small when it is large.
Therefore, a current corresponding to the operating voltage of the second driving transistor when energized is outputted (current sucked) from the transistor 93 of the detection/comparator 71 and supplied to the second selector 76 . The supplied current increases when the operating voltage of the second drive transistor is high, and decreases when the operating voltage is low.

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,
The coils 6, 7, 8 constitute a second feedback loop, and the second drive transistors 13, 14, 1
The operating voltage of the transistor in the energized state of 5 V _CE
The first drive transistors 3, 4,
A current equal to the current flowing through the coils 5 (corresponding to the command signal 23) also flows through the second drive transistors 13, 14, and 15, and current flows in both directions in the coils 6, 7, and 8 (current increases as the magnet 9 rotates). (current whose direction changes) is stably supplied.

To explain this, when the current flowing through the second driving transistor becomes transiently smaller than the current flowing through the first driving transistor, the operating voltage of the first driving transistor decreases due to the loading effect of the coil, and the operating voltage of the first driving transistor decreases. The operating voltage of the second drive transistor increases. This increase in the operating voltage is detected by the detector and comparator 71 and is transmitted via the second selector 76 to the base current of the second drive transistor.
The collector current is increased, and as a result, a current equal to the current flowing through the first drive transistor (collector current) is output from the second drive transistor. Furthermore, the operating voltage of the second drive transistor is stably controlled to a small value (approximately equal to V ₂ −V _D ) within the active region corresponding to the reference voltage V ₂ . Note that the capacitor 77 is provided for phase compensation (prevention of 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, resistor 61, diode 62, 63
As a result, a reference voltage signal _V3 having 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 ₃ is a voltage signal
It changes in conjunction with V ₁ (both V ₁ and V ₃ are command signal 2).
3), when the supply current to the coils 6, 7, and 8 (i.e., the conduction current of the first and second drive transistors) is large, the signal V ₃ is made large, and when the supply current is small, the signal V 3 is made large. V ₃ is made smaller. The emitters of the detection transistors 64, 65, and 66 serve as input terminals at reference potential points (signal
V ₃ point), and each base side is connected as a detection terminal to each output terminal of the first drive transistors 3, 4, and 5 in a direct current manner. As a result, the operating voltage (collector
Absolute value of voltage drop across emitters) and reference voltage signal
When the operating voltage value becomes smaller than _{the signal V 3 by} the emitter-base forward voltage V _D , the corresponding detection transistor 64, 65, 6
6 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 first drive transistor 4 in the energized state is lower than the voltage of the other drive transistors 3 and 5. The detection transistors 64, 65, 66 compare the operating voltages of the first drive transistors 3, 4, ₅ with the reference voltage signal V3, and in FIG. ₃ by V _D , the detection transistor 65
becomes active and outputs collector current. The output currents of each detection transistor 64, 65, and 66 are combined (collector sides are commonly connected), and a diode 67,
The voltage converter 1 is inverted and amplified by a current mirror consisting of a transistor 69 and resistors 68 and 70.
7. Therefore, an output current corresponding to the operating voltage of the first drive transistors 3, 4, and 5 during normal operation can be obtained.

The voltage converter 17 is a switching transistor that constitutes a semiconductor switching 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 resistor 102,
103 and the switching transistor 101
Switching controller 100 that controls on/off
, a flyhole diode 105 , an inductance element 106 , and a capacitor 107 . Switching controller 100
For example, various well-known configurations can be used, such as a triangular wave generator that generates a 50 kHz triangular wave voltage signal, and a comparator that converts the output of the motion 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 transistor 18 is obtained, and the switching transistor 1 is
Controls on/off of 01. The output voltage V _M of the voltage converter 17 is determined by the switching transistor 101.
On time/off time (actual on time ratio)
changes in relation to When this switching transistor 101 is on, V _i 〓V _s , and the DC power supply 1 supplies current to the load side through the inductance element 106. switching transistor 1
When 01 turns off, the flyhole diode 105 turns on and the 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 operation detection controller 18, the voltage converter 17 and the first drive transistors 3, 4, 5
A third feedback loop is constructed by detecting the operating voltage of the first drive transistors 3, 4, and 5 when they are energized, and the operating voltage is the reference voltage signal _V3.
The output voltage _VM of the voltage converter 17 is controlled to a predetermined value (approximately V ₃ −V _D ) corresponding to the voltage. To explain this, when the operating voltage of the first drive transistors 3, 4, and 5 decreases, the output current of the operation detection controller 18 increases, and the on-time of the switching transistor 101 increases due to the operation of the switching controller 100. By increasing the ratio and increasing the output voltage V _M of the voltage converter 17, the first
Increase the operating voltage of the drive transistor. The same applies to the reverse case.

Next, the overall operation of the first, second and third feedback loops will be explained. Assuming that the feedback loop is now in equilibrium, the voltage drop across the resistor 47 will be a value corresponding to the command signal 23, and the first drive transistors 3, 4, 5 and the second drive transistors 13, 14, 15 will be A current corresponding to the command signal 23 is supplied to the coil selected by the position detector 11 (first and second feedback loops), and the operating voltage of the second drive transistors 13, 14, and 15 in the energized state is is a predetermined small value in the active region corresponding to the voltage signal V ₂ (therefore, the command signal 23) (second feedback loop), and the transistors in the energized state of the first drive transistors 3, 4, 5 are The operating voltage is a predetermined small value within the active region corresponding to the voltage signal V ₃ (and therefore 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 .

When the voltage signal V ₁ becomes large, the base current, and therefore the collector current, of the first drive transistors 3, 4, and 5 in the energized state becomes large, and the current corresponding to the command signal 23 is energized (the first feedback loop). Therefore, its operating voltage becomes smaller (the current flowing through the first drive transistor becomes transiently larger than the current flowing through the second drive transistor).

A decrease in the operating voltage of the first drive transistor causes an increase in the operating voltage of the second drive transistor. The increase in its operating voltage is greater than the increase in voltage signal V ₂ (the increase in V ₂ is determined by i ₃ ),
The voltage applied between the base and emitter of the detection transistor of the detection/comparator 71 of the second distribution controller 16 becomes smaller, and the output current of the detection transistor becomes smaller. current). Therefore, the second drive transistor 13,
The base currents of the transistors 14 and 15 in the energized state, and therefore their collector currents, increase (second feedback loop), and the energized current of the second drive transistor becomes larger than the energized current of the first drive transistor. It becomes stable as it becomes equal to the current flowing through the transistor. Further, the operating voltage of the second drive transistor is a predetermined value corresponding to the voltage signal _V2 .

Due to the operation of the first and second feedback loops,
The current supplied to the coils 6, 7, and 8 is determined, and the voltage drop therebetween is also determined. Therefore, the operating voltage of the first drive transistor when it is energized is the same as that of the voltage converter 17.
From the output voltage V _M of coils 6, 7, 8, resistor 4
This is the remaining amount after subtracting the voltage drop of 7 and the operating voltage of the second drive transistor, and decreases as the conducting current increases. This decrease in the operating voltage of the first drive transistor and increase in the voltage signal V ₃ results in
The output current is increased by the operation detection controller 18, the on-time ratio of the switching transistor 101 of the voltage converter 17 is increased, and the output voltage V _M is increased (the third
feedback loop). As a result, an output voltage V _M is generated that makes the operating voltage of the first drive transistor a predetermined value corresponding to the voltage signal V ₃ and becomes stable (the whole becomes stable).

Even when the command signal 23 changes significantly, it similarly settles into a 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) The coil utilization rate is high because current flows in both directions through the coil.

(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 operation when the second drive transistor is energized are determined by the operation of the first feedback loop. Variations in 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.

In addition, in this embodiment, the reference voltage signal V 2 to be compared with the operating voltage of the second drive transistors 13, 14, ₁₅ or the first drive transistors 3, 4,
The reference voltage signal V ₃ to be compared with the operating voltage of the coils 6, 7, 8 is changed in response to the command signal 23.
When the supply current to (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 output voltage of the voltage converter 17 and the current flowing through the second driving transistor are controlled so that the operating voltage of the driving transistor becomes a small voltage value within the active region, regardless of the magnitude of the current flowing therethrough. be done. Such characteristics are important, especially when saturation of the drive transistor is taken into consideration.

In this regard, the first drive transistor 3,
The control of the operating voltage (third feedback loop) of Nos. 4 and 5 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 (7th
(see figure).

Now, consider a case where the voltage signal V ₃ is constant (the voltages across the resistor 61 and diodes 62 and 63 are constant). If the first 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
7's output voltage V _M is reduced. 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 it is within the output response range of the voltage converter 17, 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 detection/comparator 71 that detects the operating voltage of the second drive transistors 13, 14, 15 in the feedback loop operation of the voltage signal.
It is desirable to change V ₂ in conjunction with the current supplied to the coil (ie, the current flowing through the second drive transistor).

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 ₃
is constant, and the current of the constant current source 202 is connected to the resistor 8.
3. Supply to diodes 81 and 82 to keep V ₂ constant. In such a case, it is necessary to set the reference voltages V ₂ and V ₃ large in order to prevent the 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. Figure 9 shows its characteristics. If this characteristic is used, when the operating voltage of the first drive transistor becomes small and becomes saturated, 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 more 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 first 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.

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.

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 phases, but is arbitrary.

Further, although the operation detection controller 18 in the above-described embodiment was designed to detect all the operating voltages when the first drive transistors 3, 4, and 5 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 was lower than the DC power supply, but the present invention is not limited to such a case. It may also be supplied. 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 electric motor for use in, for example, audio/visual equipment 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 connection diagram showing another embodiment of the present invention, and FIG. 9 is a diagram showing detection characteristics of the operation detection controller. 1... DC power supply, 3, 4, 5... First drive transistor, 6, 7, 8... Coil, 9... Magnet, 11... Position detector, 12... First distribution controller, 13, 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, 43, 44, 45, 46
... Hall element, 48 ... Current controller, 63 ...
first selector, 64, 65, 66, 87, 88,
89...detection transistor, 71...detection/comparator, 76...second selector, 100...switching controller, 101...switching transistor.

Claims (1)

[Scope of Claims] 1. 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. K (K is 3) connected between the output terminal of the coil and each power supply terminal of the coil.
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 control means for controlling the output voltage of the conversion means. A first device that compares the operating voltage of the second drive transistor in a energized state with the first reference voltage signal, and controls the energization current of the second drive transistor in accordance with the comparison output.
and the operation detection control means includes a second reference voltage generation means for obtaining a second reference voltage signal, and a first drive transistor group in which the first driving transistor group is energized. An electric motor comprising: second comparison means for comparing the operating voltage of the drive transistor of the drive transistor with the second reference voltage signal and controlling the output voltage of the voltage conversion means according to the comparison output. 2. The electric motor according to claim 1, wherein the first reference voltage generating means changes the first reference voltage signal in response to a command signal. 3. The electric motor according to claim 1, wherein the second reference voltage generating means changes the second reference voltage signal in response to a command signal.