JPH0965680A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the stable operation of a motor by a method wherein, when currents are applied to tap terminals, a power supply voltage stepup circuit is started in accordance with the detection result of a motor rotation state detecting means and its output voltage is added to the voltage of a power supply battery by the selection of a power supply selecting means and the resultant voltage is applied to a DC motor. SOLUTION: If the revolution of a three-phase DC motor 1 exceeds a predetermined value, the level of the output of a comparator 8c is turned to be HIGH and it is detected by a motor revolution elector 8 that the revolution of the motor reaches the predetermined value and an instruction to switch the all-winding current application to the tap-terminal current application is outputted and currents are applied to tap terminals. A mechanism controller 17 turns off a power supply selection transistor 15 in accordance with the output of a selection prohibiting means 9 and the emitters of tap terminal driving transistors 5b are released from grounding to start a DC-DC converter 14. With this constitution, a resultant voltage which is obtained by adding the voltage of the DC-DC converter 14 to the voltage of a power supply battery 3 is applied to the windings of the motor 1 to increase the revolution further. As a result, the stable operation of the motor can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control circuit for a DC brushless motor, and more particularly to a DC motor having a tap terminal provided at a predetermined winding position for each phase winding used in a portable recording / reproducing device or the like. The present invention relates to a motor control circuit for driving a motor using a battery as a power source.

[0002]

2. Description of the Related Art In recent years, a portable magnetic recording / reproducing apparatus typified by a headphone stereo has a brushless three-phase drive which can be driven by a low voltage power source in order to miniaturize a motor and improve portability and reliability. DC motors have come to be adopted. In addition, it has become necessary to further reduce the time required for fast-forwarding and rewinding and to save power during normal playback.

An example of a control circuit for a conventional three-phase DC motor is disclosed in Japanese Patent Laid-Open No. 1-283088. This is to provide a tap terminal on the three-phase winding, and when the motor speed after starting reaches a predetermined value, energize using the tap terminal to reduce power consumption. In such a three-phase DC motor, a characteristic diagram showing the torque vs. current consumption is shown in FIG.
That is, in general, the consumption current when the tap terminals are energized is larger than the consumption current when all the winding terminals are energized because the number of windings decreases. Therefore, the motor control circuit driven by the power supply battery prevents excessive battery consumption.
It is common to impose a motor current limit. When the current limit value IL is applied in FIG. 9, the maximum torque value of the obtained motor is T1> T2, where T2 is the value when the tap terminals are energized and T1 is the value when all winding terminals are energized. .

FIG. 10 is a characteristic diagram showing torque-rotation speed characteristics of a three-phase DC motor when the motor current limit IL shown in FIG. 9 is applied. As shown in FIG.
When a motor load of less than the torque value T2 that reaches the motor current limit value IL in FIG. 9 is applied, the rotation speed of the motor can be higher when the tap terminals are driven than when all the winding terminals are driven. Further, when the motor is started or when a motor load exceeding the torque T2 that reaches the motor current limit value IL is applied, the motor rotation speed becomes smaller when the tap terminals are driven than when the all winding terminals are driven. From the characteristics of FIG. 10, it is ensured that the starting torque is driven by energization of all winding terminals, and when the required torque becomes a certain value or less, switching to energization of tap terminals is performed, and a higher rotation speed is achieved in a shorter time. Can be reached

[0005]

However, as shown in FIG. 9 and FIG. 10, the conventional motor control circuit as described above is a motor control circuit due to a change in ambient temperature during tap terminal energization after startup. If the load is excessive and the motor current increases, and the motor current limiting circuit executes the motor current limiting, the motor rotation speed will decrease. In such a situation, if the switching from tap terminal energization to full-winding energization is not possible, the number of revolutions cannot be maintained, and the motor current increases to the current limit value. It had a problem that it would become.

Further, when there is a motor load fluctuation, that is, a torque fluctuation near the current limit value, while the tap terminal is energized,
The motor speed changes up and down. Therefore, first, the rotation speed of the three-phase DC motor decreases, and the preset value N
When it is detected that the following has been reached, energization of all winding terminals is performed and the rotation speed increases. However, when the number of revolutions exceeds a preset value N, the tap terminal is switched to energization again, and thereafter, the energization switching is repeated every time a change in the number of revolutions is detected, and the operation becomes unstable. Was there.

In the conventional motor control circuit, when the battery is used as a power source, when the tap terminal is energized and the battery capacity is exhausted and the power supply voltage drops, the tap terminal is energized. In order to maintain the above condition, the motor current increases to the current limit value, so that the power supply voltage further decreases, and the motor rotation speed cannot be maintained, which causes a decrease.

Further, since the motor control circuit of the conventional example executes switching from energization of all winding terminals to energization of tap terminals even when the power source voltage of the battery is lowered, the motor current increases. And further reduce the power supply voltage,
Despite the intention of high-speed rotation, there was a problem that the number of rotations was rather reduced as compared with the case where all windings were energized.

The present invention is intended to improve the problems of the above-mentioned conventional example, and particularly in the case of fast-forwarding and rewinding of the magnetic tape, the load fluctuation of the motor due to the factors such as the change of the ambient temperature and the battery It is an object of the present invention to provide an excellent motor control circuit that maintains a rotation speed in a wider range and realizes stable operation with respect to a decrease in power supply voltage when used as a power supply.

[0010]

In order to achieve the above object, the motor control circuit of the present invention drives a direct current motor having a tap terminal at a predetermined winding position of each phase winding by using a battery as a power source. A motor control circuit comprising: a motor energization terminal selection means for switching between energization of all winding terminals and energization of tap terminals; a motor rotation state detection means for detecting a rotation state of the DC motor; and a power supply for boosting the voltage of the power supply battery. A booster circuit, and a power source selecting means for selecting and applying a power source for the motor when the tap terminal is energized by the power source battery and a booster power source to which the voltage is applied by activating the booster circuit in the power source battery. After starting the DC motor by energizing all winding terminals, the motor energizing terminal selecting means selects tap terminal energizing according to the detection result of the motor rotation state detecting means, and The source selection means activates the power supply booster circuit when the tap terminal is energized according to the detection result of the motor rotation state detection means, and applies to the DC motor as a boosted power supply in addition to the voltage of the power supply battery by the selection of the power supply selection means. It has a basic configuration.

This basic configuration further includes selection prohibiting means for prohibiting the power source selecting means from selecting the boosting power source and the motor energizing terminal selecting means performing the tap terminal energizing selection. When the motor rotation state detecting means detects that the number of rotations of the motor has decreased during driving by energizing the tap terminals, the power supply selecting means stops the power supply boosting circuit to switch the motor applied voltage, and the motor energizing terminal selecting means taps. A configuration may be added in which energization of all winding terminals is selected from terminal energization, and thereafter, the selection prohibiting means prohibits the step-up power source selection and tap terminal energization selection operations.

[0012]

According to the present invention, with the above-described structure, the motor is started by energizing all winding terminals to generate a large torque at the constant speed rotation, and when the predetermined rotation speed is reached, the motor rotation state detecting means detects this and the motor is detected. The energization terminal selection means switches from tap terminal energization to all winding terminal energization, and the power supply selection means switches from battery power supply to boost power supply to perform high-speed rotation. When it becomes impossible to maintain the rotation speed of the motor, the motor rotation state detection means detects this, the power source selection means switches from step-up power source to battery power source, and the motor energization terminal selection means switches from tap terminal energization to all winding terminal energization. This suppresses an increase in motor current, and acts so that the motor rotation speed is exhibited up to the maximum capacity of the motor.

In the configuration further including the selection prohibiting means, the power source selecting means switches from the boosting power source to the battery power source,
After the motor energization terminal selection means switches from tap terminal energization to full-winding terminal energization, the selection prohibition means prohibits the selection operation between the boost power supply and tap terminal energization, so the load is temporarily reduced and the specified rotation speed is reached. Even if it recovers to the number, the energization switching from the battery power supply to the boosting power supply will not be executed again from all winding terminals to tap terminal drive, and the energization switching will not be repeated due to torque fluctuations and the operation will not become unstable. Acts like.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 is a block diagram of a motor control circuit according to a first embodiment of the present invention. In FIG. 1, the three sets of windings 2 of the three-phase DC motor 1 each have a tap terminal 2 a, and the output of the motor drive circuit 7 that generates a current for driving the motor 1 is output from the motor energization terminal selection means 6. Input terminal 6
Enter in c. All winding terminal energizing terminals 6a of the motor energizing terminal selecting means 6 are connected to all winding terminals of the winding 2 through the base resistance 5c of the switching transistor circuit 4 for driving the motor 1 and the all winding terminal driving transistor 5a,
On the other hand, the tap terminal energizing terminal 6 of the motor energizing terminal selecting means 6
b to the base resistance 5c of the switching transistor circuit 4 for driving the motor 1, the tap terminal driving transistor 5
Tap terminal 2 provided at a predetermined winding position of winding 2 via b
connected to a.

The output of the voltage generator 8a which generates a voltage according to the rotation speed of the motor 1 is input to the motor rotation speed detection circuit 8. The voltage generator 8a and the motor rotation speed detection circuit 8 form a motor rotation speed detection means which is one of means for detecting the motor rotation state. The output of the motor speed detection circuit 8 is input to the selection prohibiting means 9, and the output of the selection prohibiting means 9 is input to the motor energization terminal selecting means 6. The emitter of the tap terminal driving transistor 5b of the switching transistor circuit 4 for driving the motor 1 is a power source boosting circuit D.
It is connected to the -Vdd terminal of the DC output voltage of the C-DC converter 14 and the collector of the power source selection transistor 15, and D
The (+) output voltage terminal of the C-DC converter 14 is grounded. The output of the motor current detection means 13 of the motor 1 is applied to the motor current limiting circuit 12, and the motor current limiting circuit 1
The output of 2 is given to the motor drive circuit 7. The mechanism controller 17 controls the entire mechanism including the motor control circuit. The outputs of the first and second reel sensors 16a and 16b, which are coupled to a reel stand (not shown) that drives the magnetic tape and detect the rotation thereof, are input to the mechanism controller 17. The (+) terminal of the power supply battery 3 having the voltage Vcc is given to the entire motor control circuit via the common terminal of the winding 2 of the motor 1 and the power switch 10.
The (-) terminal is grounded.

Here, as shown in FIG. 2 which is a block diagram showing in detail the main parts in FIG.
Is a sample and hold circuit 8b that receives the output of the voltage generator 8a, a comparator 8c, and a reference voltage source 8d.
It consists of. Further, the selection prohibiting means 9 which also serves as the initial setting means includes a flip-flop circuit 9a and an AND circuit.
The output of the flip-flop circuit 9a is reset to H level when the power is turned on.
It is IGH. Also, the motor energization terminal selection means 6
Are transistors Q1 to Q8 and current sources I1, I
2, the transistor Q5 serves as a switching input terminal of the motor energization terminal selection means 6. The motor energizing terminal selecting means 6 shown in FIG.
It is a circuit for each phase. In case of 3 phases, it corresponds to each winding.
It consists of three circuits.

The operation of the first embodiment of the present invention configured as described above is shown in FIG. 7 of the torque vs. current consumption characteristic diagram of the motor in the embodiment of the present invention, and similarly, the torque vs. speed characteristic of the motor. A description will be given in combination with FIG. First, when the power switch 10 is turned on to start the motor, the voltage generator 8a generates a voltage corresponding to the motor rotation speed, and the sample hold circuit 8 in the motor rotation speed detection circuit 8 is generated.
Until the output voltage of b exceeds the voltage value of the reference voltage source 8d set according to the predetermined rotation speed, the output of the comparator 8c is LOW, and the flip-flop circuit 9a described above is used.
Is initially reset to HIGH, and therefore the output of the AND gate 9b, that is, the output of the selection prohibiting means 9 also serving as the initial setting means becomes LOW, the transistor Q5 of the motor energization terminal selecting means 6 is turned off, and the current Sources I1 and I2 are activated and transistor Q
6, Q8 is on, Q7 is off, and the output of the motor drive circuit 7 input to the input terminal 6c is the transistor Q.
The current mirror circuit composed of 1, Q2 and Q3 outputs the current to all winding terminal energization / transmission terminals 6a to drive all winding terminal driving transistors 5a. Therefore, the motor is energized in all windings, and the maximum torque at startup is secured by energizing all windings.

Next, when the motor speed exceeds a predetermined value, the output voltage of the sample hold circuit 8b exceeds the voltage value of the reference voltage source 8d, and the output of the comparator 8c becomes LOW.
Becomes HIGH, the motor rotation speed detection circuit 8 detects that the rotation speed of the three-phase DC motor 1 has reached a preset value, and the motor rotation speed detection circuit 8 energizes all winding terminals rather than tap terminals. The command to switch to is output.
At this time, since the flip-flop 9a remains HIGH in the initial state, the selection prohibiting means 9 becomes invalid, the output of the AND gate 9b switches to HIGH, and the selection prohibiting means 9
The output of is switched from LOW in the previous state to HIGH, the transistor Q5 is turned on, the transistors Q6 and Q8 are turned off, Q7 is turned on, and the output of the motor drive circuit 7 input to the input terminal 6c is the transistors Q1, Q2 and In the current mirror circuit composed of Q4, tap terminal energizing terminal 6b
To drive the tap terminal driving transistor 5b. At this time, the mechanism controller 17 gives a HIGH potential to the base of the power supply selection transistor 15 and grounds the emitter of the tap terminal driving transistor 5b.
Therefore, the motor 1 is energized with the tap terminals.
Therefore, it is possible to reach the high rotation speed in a shorter time by switching to the tap terminal energization after securing the maximum torque at the start by energizing all the windings.

Next, the selection of the boosting power source will be described.
By the output of the selection prohibiting means 9 to the mechanism controller 17, the mechanism controller 17 gives a LOW potential to the base of the power source selection transistor 15 to turn it off, and releases the ground of the emitter of the tap terminal driving transistor 5b, and at the same time DC-DC. The converter 14 is started.
This operation is referred to as power source selection means. This allows the power battery 3
Is added to the winding of the motor 1, and the rotation speed of the motor 1 is further increased. This step-up power supply selection may be performed simultaneously with switching from energization of all winding terminals to energization of tap terminals, and a higher rotation level than switching to energization of tap terminals by checking the motor rotation state detection means by the mechanism controller 17. May be performed after detection of.

When the step-up power source selection is performed simultaneously with switching from energization of all winding terminals to energization of tap terminals, FIG. 7 and FIG.
As can be seen from the above, the motor rotation speed detection circuit 8 is set so as to be performed after the rotation speed corresponding to the torque T3 is reached by energizing all winding terminals. If this is not the case, switching from energization of all winding terminals to energization of tap terminals is performed at a motor rotation speed corresponding to torque T2, and boosting power source selection is further performed at a motor rotation speed corresponding to torque T3. Therefore, a second motor rotation speed detection means and a second selection prohibition means, which are not shown, are provided, and this output is input to the mechanism controller 17.

When the load of the motor 1 becomes excessive while the tap terminal is energized and the motor current detected by the motor current detecting means 13 increases to the current limit value, the motor current limiting circuit 12 executes the motor current limiting and the motor current limiting circuit 12 executes the motor current limiting. When the rotation speed drops below a predetermined value, the motor rotation speed detection circuit 8
Detects this, and the output becomes LOW. At this time, the output of the flip-flop circuit 9a is held at LOW, and the flip-flop circuit 9a is in the JK type from HIGH to L.
If a type that inverts to OW but does not invert from LOW to HIGH is used, the power switch 10
The state of LOW shall be maintained until it is turned off and reset. The output of the AND gate 9b, that is, the output of the selection prohibiting means 9 becomes LOW, the transistor Q5 is turned off, the output of the motor drive circuit 7 is output to the all-winding terminal energizing terminal 6a, and the all-winding terminal driving transistor 5a is driven. . Therefore, the motor 1 is again energized for all winding terminals. The step-up power source selection may be released by reversing the step-up power source selection procedure. The step-up power source selection release operation may be performed at the same time as switching from tap terminal energization to all winding terminal energization. The tap terminal energization may be switched to the full winding terminal energization at a lower motor rotation level in response to the selection canceling operation. In this case, the motor rotation speed detecting means may be set in the same manner as when starting up.

When the load on the motor 1 is reduced and the motor rotation speed rises again and exceeds a predetermined value, the rotation speed detection means 8
Outputs HIGH, but the flip-flop circuit 9a
Output of the AND gate 9b is LOW, that is, the output of the selection prohibiting means 9 remains LOW and the transistor Q5 remains OFF, so that the motor 1 has all winding terminals. Keep the power on, motor 1
As long as the energization to the motor is continued, the selection prohibition means 9 ignores the subsequent tap terminal energization switching command from the motor rotation speed detection circuit 8, holds the state in which the selection operation of the motor energization terminal selection means 6 is prohibited, and again. The operation to switch to tap terminal energization and boost power source selection is prohibited. That is, once the instruction to switch the motor energization terminal selection means 6 from the energization of the tap terminals to the energization of all winding terminals passes through the selection prohibition means 9 once, the selection prohibition means 9 changes the motor energization terminal selecting operation to the following state. Hold as long as power is supplied.
By this operation, it is possible to avoid the problem of the conventional example that the operation becomes unstable by repeating the energization of all winding terminal energization, tap terminal energization, and step-up power supply selection each time a change in the rotation speed is detected.

As described above, according to this embodiment, when the three-phase DC motor is started, the output of the motor drive circuit 7 is applied to all winding terminals by the selection prohibiting means 9 which also serves as initial setting means, and all windings Terminal energization is executed. Next, when the rotation speed of the motor 1 reaches a preset value,
The energization of all winding terminals is switched to the energization of tap terminals, and the step-up power source of the DC-DC converter is selected by the power source selecting means. In this way, the maximum torque at startup can be ensured by energizing all windings, and a high rotation speed can be reached in a short time by energizing the tap terminals and selecting the boosting power source.

When the tap terminal is energized and the step-up power source is selected, the load becomes excessive during operation, the motor current is limited, and the motor rotation speed falls below a predetermined value. Switching to the terminal energization is performed through a step opposite to that in the start-up state, and subsequent tap terminal energization and boost power supply selection switching command are prohibited.
Therefore, it is possible to prevent the operation from becoming unstable by repeating energization switching between energization of all windings and energization of tap terminals and selection of boosting power source.

The selection prohibiting means 9 is used only when the tap terminal energization is switched to the full winding terminal energization as described above, and the second selection prohibiting means is switched only when the boosting power source is switched to the battery power source. Since it only inhibits the selection operation output, it can be easily realized by a microcomputer or the like in addition to the above flip-flop circuit, and may be incorporated in the mechanism controller 17. Further, the selection prohibiting means 9 and the second selection prohibiting means stop the motor 1 or open the power switch 10 to release the power supply state to the selection prohibiting means 9,
The selection operation prohibition state is released.

As for the method of detecting the rotation speed of the motor rotation speed detecting means, the detection is performed by using the frequency pulse generated by the frequency generator coupled to the motor 1 instead of the induced voltage value depending on the rotation speed of the motor described above. You may. Instead of detecting the motor rotation speed itself, the motor rotation speed may be indirectly calculated by measuring the motor current as can be seen from FIGS. 7 and 8.

Regarding the rotation speed detection response time of the motor rotation speed detection means 8, a predetermined time lag may be provided as speed setting delay means so as not to malfunction due to momentary overload or the like. Further, the state of the selection prohibiting means 9 may be held by an internal memory of a system control circuit such as a microcomputer instead of the illustrated flip-flop circuit.

Further, the power switch may be switched by a microcomputer or the like based on the information of the motor stop command switch. FIG. 3 is a block diagram of a main part of a motor control circuit according to a second embodiment of the present invention. In FIG. 3, the power supply voltage detecting means 11 and the power supply voltage detecting means 11 in FIG. 1 of the first embodiment are shown. And an OR circuit 14 which receives the output of the motor rotation speed detection circuit 8 and outputs it to the selection prohibiting means 9. That is, the power supply voltage detection means 11 is connected to the power supply line after passing through the power supply switch 10, the output side thereof and the output side of the rotation speed detection means 8 are connected to the input of the OR circuit 14, and this OR circuit 14 is connected. Is connected to the input side of the selection prohibition means 9.

The operation of the motor control circuit according to the second embodiment will be described below. First, the operation at the time of starting the motor is similar to that of the first embodiment. When the power supply battery is exhausted and the power supply voltage is reduced while the tap terminal is energized and the boosted power supply is selected, the motor current increases to try to maintain the rotation speed, but the power supply voltage detection means 11 does not exceed a predetermined voltage value. When the output is detected, the output of the OR circuit 14 commands the switching of the motor energization terminal selection means 6 via the selection prohibition means 9 to switch the energization from tap terminal drive to all winding terminal drive, Motor drive circuit 7
Is supplied to the transistor 5a for driving all winding terminals. In this case, the setting of the motor rotation speed or the power supply voltage corresponding to the torque is the same as that of the first embodiment depending on whether the step-up power supply selection is canceled or simultaneously performed before switching the energization from tap terminal drive to all winding terminal drive. Just go. Here, as in the first embodiment, when the switching command from the tap terminal energization to the motor energization terminal selection means 6 to all winding terminal energization once passes through the selection prohibition means 9 or the second selection prohibition means, the motor 1 As long as the power supply to the motor is continued, the state of prohibiting the subsequent motor power supply terminal selection operation is maintained.
Therefore, when the energization switching from tap terminal energization to all winding terminal drive is executed, the subsequent tap terminal energization switching command from the motor rotation speed detection circuit 8 is prohibited.

Further, the selection prohibiting means 9 cancels the selection operation prohibiting state by stopping the motor 1 or opening the power switch 10 to cancel the power supply state to the selection prohibiting means 9. Regarding the response of the voltage detection operation of the power supply voltage detection means 11, as a voltage value setting delay means, it is invalidated so as not to malfunction due to a power supply voltage drop at the moment when a motor starting current is generated at the time of motor startup. A time lag should be provided.

FIG. 4 is a block diagram of an essential part of a motor control circuit according to a third embodiment of the present invention. In FIG.
3 of the above embodiment, the power supply voltage detecting means 11
The power source is connected to the power source battery 3 side of the power source switch 10, and the power source battery is directly backed up without the power source switch 10. The operation of the motor control circuit of the third embodiment will be described below.
In this example, as in the second embodiment, the power supply battery is exhausted while the tap terminal is energized and the boosting power supply is selected, the power supply voltage is lowered, and the power supply voltage detection means 11 is below a predetermined voltage value. When the motor drive circuit 7 receives the output of the selection prohibition means 9, the motor energization terminal selection means 6 outputs the energization switching from tap terminal drive to all winding terminal drive, and the motor drive circuit 7
Is supplied to the transistor 5a for driving all winding terminals. Once the switching output from the motor energization terminal selection means 6 to the energization of all winding terminals passes through the selection prohibition means 9 once, the motor energization terminal selection operation is maintained as long as the motor energization is continued. To do.

Therefore, energization switching to all winding terminal drive is executed, and the subsequent tap terminal energization switching command from the motor rotation speed detection circuit 8 is prohibited. Further, since the power supply terminal of the power supply voltage detection means 11 is directly connected to the power supply battery 3 without passing through the power supply switch 10, the selection prohibition operation described above is maintained even when the motor 1 is stopped. Then, when the power switch 10 is turned on again to restart the motor 1, the tap terminal energization does not switch. The selection prohibition state described above is canceled by replacing the power supply battery 3.

The setting of the motor rotation speed or the power supply voltage corresponding to the torque is the same as that of the first embodiment depending on whether the boosting power source selection is canceled or simultaneously performed before switching the energization from the tap terminal drive to the all winding terminal drive. All you have to do is think. Regarding the response of the voltage detection operation of the power supply voltage detection means 11, a time lag is provided so as to invalidate the power supply voltage drop at the moment when the motor starting current is generated, as in the second embodiment. .

FIG. 5 is a block diagram of essential parts of a motor control circuit according to a fourth embodiment of the present invention. In the figure, the difference from the third embodiment of FIG. 4 is that both power supply terminals of the selection prohibition means 9 and the power supply voltage detection means 11 are directly backed up by the power supply battery 3 without passing through the power switch 10. is there. The operation of the motor control circuit of the fourth embodiment will be described below. The basic operation is similar to that of the third embodiment. However, since the power supplies of the power supply voltage detection means 11 and the selection prohibition means 9 are both directly connected to the power supply battery 3 without passing through the power supply switch 10, while the motor 1 is stopped or the power supply switch 10 is open, Power battery 3
Is consumed and the power supply voltage drops below a specified voltage value,
The power supply voltage detection means 11 performs the detection operation. When the power switch 10 is turned on again to restart the motor 1, the selection prohibiting means 9 prohibits the tap terminal energization selecting operation by the motor energizing terminal selecting means 6 and only drives by energizing all winding terminals. Run. The selection prohibition state described above is canceled by replacing the power supply battery 3.

The setting of the motor rotation speed or the power supply voltage corresponding to the torque is the same as that of the first embodiment depending on whether the boosting power source selection is canceled or simultaneously performed before switching the energization from tap terminal driving to full winding terminal driving. All you have to do is think. As for the response of the voltage detection operation of the power supply voltage detection means 11, it is invalidated so as not to malfunction due to the power supply voltage drop at the moment when the motor starting current is generated at the time of starting the motor, as in the second embodiment. You can set a time lag in.

The fifth embodiment of the present invention will be described below. In the first embodiment, the switching between tap terminal energization and full-winding terminal energization, and boost power source selection and its release timing depend on the change in the motor rotation speed by the motor rotation speed detection means which is the motor rotation state detection means. But
Instead of this, the first motor of FIG.
Alternatively, the detection result of the tape position detecting means using the second reel sensors 15a and 15b may be used. As is well known, the ratio of the rotational speeds of both reels changes every moment due to the change in the amount of the magnetic tape wound on both reels.Therefore, if this rotational speed ratio is calculated, how much magnetic tape will be wound on each reel. You can determine whether there is. For early tape winding, when the amount of tape wound on the reel on the winding side is small, the winding torque may be small, so immediately after startup, all winding terminals are energized, tap terminals are energized, and the boost power supply is selected. It may be switched, but if the start-up is at a point equal to or higher than the middle of the tape winding amount, a large torque is required, so it is preferable to wind with battery power without switching to boost power source selection until the end.

By changing the flow of the detection signal and the control signal of FIG. 1 of the first embodiment, the voltage generator 8a, the motor current detection means 13, the first and second reel sensors 16a and 16b.
All the outputs of the sensors such as are input to the mechanism controller 17 having a microcomputer to make a judgment,
Based on the result, the mechanism controller 17 controls the motor energization terminal selection means 6, the motor drive circuit 7, the motor current limiting circuit 12, the DC-DC converter 14, the power supply selection transistor 15, etc., and the function of the selection prohibition means 9 is It will be described as being processed by a program.

Step 601 in FIG. 6 of the flow chart showing the algorithm for acceleration / deceleration of the fifth embodiment.
At step 602, the motor energizing terminal selecting means 6 selects all winding terminals, the power source selecting transistor 15 which is the power source selecting means is turned on, and the battery power source is selected to start in the low speed mode. In step 603, the tape position is detected. To this end, the rotational speeds of the first and second reel sensors 16a and 16b are calculated by the microcomputer of the mechanism controller, and due to the difference in the rotational speeds, the magnetic tape is only slightly wound around the winding side reel. Determine whether it is at the winding start position, in the middle, or at the winding end. Since this technique is already known, its details are omitted. Step 60 if it is between the middle and the end of winding
8. If it is from the beginning of winding to the middle, go to step 604. In step 604, the microcomputer issues a command for speed-up mode 1, the motor energization terminal selection means 6 selects tap terminals, and in step 605 commands the start of the DC-DC converter 14, and at the same time, power supply selection means which is power supply selection means. The transistor 15 is turned off to select the step-up power source, and the step-up power source is applied to the tap 2a of the winding 2 of the motor 1 to rotate at high speed at, for example, 6,500 to 7,000 revolutions (acceleration mode 1). When switching to the step-up power source in step 605, the motor rotation state detecting means such as the motor rotation number detecting circuit 8 may be used to judge whether the motor has already reached a specific rotation number, for example, 5,000 rotations or more.

In step 606, when the motor rotation state detecting means detects that the number of rotations of the motor 1 is 4,000 or less, the microcomputer issues a step-up stop instruction in step 607 and outputs the DC-DC converter 14.
Is stopped, and at the same time, the power source selection transistor 15 is instructed in step 608 to switch from the boost power source to the battery power source, so that the motor energization terminal selection means 6 is in the tap terminal selection state (acceleration mode 2). In step 609, the microcomputer checks the output of the motor current detection means 13, and if it detects that the current limit IL has been exceeded, in step 610 the motor energization terminal selection means 6 selects all winding terminals and shifts to the low speed mode. To do. Step 6
At 11 there is a user stop instruction, or the end of the winding of the magnetic tape is detected, and the process ends. Here, in the steps after step 607, the function of the selection prohibition means can be provided by creating a program of the microcomputer so as not to return to the previous mode.

In the present embodiment, as the motor rotation state detecting means, not the detection result by the first and second reel sensors 15a and 15b but the detection result of the motor rotation number detecting circuit 8 and other means described above are used according to the necessity of the state. Of course, they may be used in combination. The configurations of the above-described embodiments may be implemented in combination, and the details of the configurations and operations of the individual embodiments are not limited. Further, the numerical values used in the examples are merely examples, and the present invention is not limited to these numerical values.

[0041]

As described above, the motor control circuit of the present invention comprises motor energization terminal selection means for switching between energization of all winding terminals and energization of tap terminals, and motor rotation state detection means for detecting the rotation state of the DC motor. , A power supply booster circuit that boosts the voltage of the power supply battery, and a power supply that selects and applies the motor power supply when the tap terminal is energized, the power supply by the power supply battery or the booster power supply that activates the booster circuit to the power supply battery and adds this voltage And a tap terminal after the power supply selecting means selects the step-up power supply and the motor energization terminal selection means once selects the step-up power supply and switches the tap terminal energization state to all winding terminal energization. It is also possible to adopt a configuration including a selection prohibition unit that prohibits selection of energization and selection of boosting power supply.

With the above-described structure, energization of all winding terminals is executed at the time of starting, a large torque at the time of starting is secured by energizing driving of all winding terminals, and then tap terminal energization driving and DC-DC converter of the power source selecting means. By selecting the boosting power source, it is possible to reach a high rotation speed in a short time. When the load increases and the motor current increases to the current limit value while the tap terminal is energized, and the predetermined rotation speed cannot be maintained, the motor rotation speed detecting means detects this and the DC-DC
The converter is stopped to deselect the boost power supply, and the motor energization terminal selection means increases the generated torque by switching from energization of the tap terminals to energization of all winding terminals. The rotation can be controlled by a number, and an increase in current can be suppressed.

In the case where the selection prohibiting means is provided, the selection prohibiting means prohibits the motor energizing terminal selection operation and the boosting power source selecting operation after the tap terminal energization is switched to the all winding terminal energization. Even if it decreases and rises to the specified speed, the energization switching from all winding terminals to tap terminal drive is not executed again, and the energization switching is repeated due to torque fluctuations and the motor speed fluctuates Does not become unstable.

In this way, while checking the rotation state of the motor, a high power supply and a high torque are drawn out from the motor in a well-balanced manner with a limited power supply, the motor current is reduced, consumption of the power supply battery capacity is prevented, and load fluctuations occur. It is possible to prevent the speed control from becoming unstable due to fluctuations in the power supply voltage.

[Brief description of drawings]

FIG. 1 is a block diagram of a motor control circuit according to a first embodiment of the present invention.

[FIG. 2] Similarly, a detailed block diagram of the main part thereof.

FIG. 3 is a block diagram of an essential part of a motor control circuit of the second embodiment.

FIG. 4 is a block diagram of an essential part of a motor control circuit of the third embodiment.

FIG. 5 is a block diagram of essential parts of a motor control circuit of the fourth embodiment.

FIG. 6 is a flow chart showing an algorithm of acceleration / deceleration of the fifth embodiment.

FIG. 7 is a torque vs. current consumption characteristic diagram of a motor according to an embodiment of the present invention.

FIG. 8 is a torque vs. rotational speed characteristic diagram of the same motor.

FIG. 9 is a characteristic diagram of motor torque vs. current consumption in a conventional motor control circuit.

FIG. 10 is a torque vs. rotational speed characteristic diagram of the same motor.

[Explanation of symbols]

 1 3-phase DC motor 2 Winding of 3-phase DC motor 2a Intermediate tap 3 Power battery 4 Switching transistor circuit 5a All winding terminal driving transistor 5b Tap terminal driving transistor 6 Motor energizing terminal selecting means 7 Motor driving circuit 8 Motor rotation speed Detection circuit 9 Selection prohibition means 10 Power switch 11 Power supply voltage detection means 12 Motor current limiting circuit 13 Motor current detection means 14 DC-DC converter 15 Power supply selection transistors 16a, 16b Reel sensor 17 Mechanism controller

Claims (9)

[Claims] 1. A motor control circuit for driving a DC motor having a tap terminal provided at a predetermined winding position of each winding of each phase by using a battery as a power source, wherein the motor switches between all winding terminal energization and tap terminal energization. Energization terminal selection means, motor rotation state detection means for detecting the rotation state of the DC motor, power supply booster circuit for boosting the voltage of the power supply battery, and motor power supply when the tap terminal is energized by the power supply battery. A power source selecting means for activating the booster circuit in the power source battery and selecting and applying a boosted power source to which this voltage is applied, and after starting the DC motor by energizing all winding terminals, the motor energizing terminal The selecting means selects tap terminal energization based on the detection result of the motor rotation state detecting means, and the power source selecting means selects the tapping current according to the detection result of the motor rotation state detecting means. Motor control circuit for activating the power supply boost circuit during flop terminals energized, characterized by being configured to apply to the DC motor as a step-up power source in addition to the voltage of the power supply battery by the selection of the power source selection unit. 2. A power supply selecting circuit is provided with selection prohibiting means for prohibiting that the power supply selecting means selects a step-up power supply and that the motor energizing terminal selecting means performs tap terminal energizing selection. In addition, when the motor rotation state detection means detects that the number of rotations of the motor has decreased, the power supply selection means stops the power supply booster circuit to switch the motor applied voltage, and the motor energization terminal selection means selects all winding terminals from the tap terminal energization. 2. The motor control circuit according to claim 1, wherein energization is selected, and thereafter, the boosting power source selection and tap terminal energization selection operations are prohibited by the selection prohibiting means. 3. A power supply voltage detecting means for detecting that the power supply voltage is equal to or lower than a predetermined voltage value, a power supply selecting means selects a boosted power supply, and a motor energizing terminal selecting means performs tap terminal energizing selection. When a voltage drop is detected by the power supply voltage detection means during driving by selecting the boosted power supply and energizing the tap terminals, the power supply selection means stops the power supply booster circuit to stop the motor applied voltage. The motor energization terminal selecting means selects all winding terminal energization from the tap terminal energization, and thereafter, the selection prohibiting means prohibits the step-up power source selection and the tap terminal energization selecting operation. The motor control circuit according to claim 1. 4. The motor rotation state detection means is any one of a motor rotation speed detection means, a power supply voltage detection means, a motor current detection means and a tape position detection means for calculating outputs of two reel sensors, or a control content. The motor control circuit according to claim 1 or 2, wherein the motors are selectively used as needed. 5. The prohibition state of the selection operation of the motor energizing terminal and the boosting power source of the selection inhibiting means is configured to be released when the motor is stopped or the power supply to the motor control circuit is stopped. The motor control circuit according to claim 2 or 3. 6. A power supply voltage holding circuit for constantly supplying a power supply voltage to the power supply voltage detection means, wherein when a decrease in the power supply voltage is detected by the power supply voltage detection means during driving by selecting a boosted power supply and energizing a tap terminal,
The power supply selecting means stops the power supply boosting circuit to switch the motor applied voltage to the battery power supply, the motor energizing terminal selecting means switches from tap terminal energization to all winding terminal energization, and thereafter, the selection prohibiting means energizes the tap terminal energizing and boosting power supply. In addition to prohibiting the selection operation of the motor, the prohibition state of the selection operation of the motor energizing terminal and boosting power supply by this selection prohibiting means is not canceled by stopping the motor or stopping the power supply to the motor control circuit by the power supply battery. The motor control circuit according to claim 3, wherein the motor control circuit is configured to hold the motor. 7. The power supply voltage holding circuit constantly supplies the power supply voltage to the selection prohibiting means, and the operation of the selection prohibiting means together with the power supply voltage detecting means is always held by the power supply battery so that the motor is stopped while the motor is stopped. When the output of the voltage drop by the power supply voltage detection means is detected, the selection prohibition means prohibits subsequent tap terminal energization and boost power supply selection operation to energize all winding terminals and drive the motor by battery power. 7. The structure according to claim 6, wherein
Motor control circuit as described. 8. A motor rotation speed detection means is provided as the motor rotation state detection means, and a speed setting delay means for delaying the response of the rotation speed detection operation of the motor rotation speed detection means is provided, and a transient transient such as an overload occurs. The motor control circuit according to claim 1, wherein the speed detection response is delayed in the state. 9. A response which reaches a set value of a power supply value of a power supply boosting circuit in a transient state such as a momentary drop of the power supply voltage, comprising a voltage value setting delay means for delaying a response of the voltage detection operation of the power supply voltage detection means. 4. The motor control circuit according to claim 3, wherein the motor control circuit is configured to delay.