JPH06165586A - Motor control circuit and motor sheet employing it - Google Patents

Abstract

PURPOSE:To allow PWM control of rotational speed of a motor using one semiconductor by selecting the rotational direction of a motor through a mechanical contact relay and controlling the rotational speed of motor means of a semiconductor. CONSTITUTION:Forward/reverse switches SW1 to SWN are connected with motors M1 to MN, respectively. Each of the switches SW1 to SWN is constituted of relays RLa, RLb. A semiconductor TR1 for controlling the speed of the motors M1 to MN is connected, in common, with the forward/reverse switches SW1 to SWN. In the relays RLa, RLb constituting the forward/reverse switches SW1 to SWN, relay contacts are switched exclusively to ON and OFF sides thus reversing current flow of the motors M1 to MN. In a current path established by the forward/reverse switches SW1 to SWN and the motor M1 to MN, the semiconductor TR1 controls currents flowing through the motors M1-MN. This constitution allows PWM rotational speed control of the motors M1 to MN using one semiconductor TR1.

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 suitable for a device driven by one or more motors, such as a vehicle seat.

[0002]

2. Description of the Related Art In recent years, in a driver's seat, a passenger's seat, etc. of a vehicle, a seat motor, a reclining angle, a height of a headrest, etc. are electrically adjusted using a motor. Some of the movable parts of the seat move in a manner other than rotational motion such as linear motion and require a converter for the motion direction between the motor and the movable parts, which are well known techniques. Since it is not related to the action and effect of, it will be omitted in the following description. A chair having an electric movable portion, such as a car seat, will be referred to as an "electric seat" in the following description. In addition, adjusting these movable parts to the user's preferred position, angle, and height is referred to as "position adjustment".

FIG. 15 shows the position adjustment of the electric seat.
It is a conventional example of a motor control circuit using a relay. By exclusively switching one of the relays RL151 and RL152 to the ON side, the rotation direction of the motor M151 is controlled.
(Although the rotation directions of the motors are relative, in the following description, forward rotation refers to the case where a current flows from the upper terminal to the lower terminal of the motor in the drawings.) Relay RL151
Is ON and the relay RL152 is OFF, the motor M151 rotates forward. On the other hand, relay RL151 is OFF
If the relay RL152 is ON, the motor M151
Rotates in reverse.

However, the motor control circuit using the relay shown in FIG. 15 has problems such as contact welding of the relay and contact failure such as conduction failure. That is, in the configuration of FIG. 15, only the relay controls the drive current of the motor, and therefore chattering caused by switching the relay contact and the current flowing through the relay contact cause the relay contact to become hot and cause the contact welding. , And contact failure due to contact wear (hereinafter referred to as “wear”).

Conventionally, in order to avoid the above problems of the motor control circuit using the relay, a motor control circuit in which all the relays are replaced with semiconductors has been used. Fig. 16
Is a conventional example of a motor control circuit using such a semiconductor. By turning on the semiconductors TR161 and TR162 and turning off the semiconductors TR163 and TR164, the motor M
161 rotates forward. On the other hand, by turning off the semiconductors TR161 and TR162 and turning on the semiconductors TR163 and TR164, the motor M161 rotates in the reverse direction.

FIG. 17 shows an example of the moving speed of the movable portion in the position adjustment of the electric seat using these conventional motor control circuits.

[0007]

DISCLOSURE OF THE INVENTION In a motor control circuit using a mechanical contact type relay as shown in FIG.
There is a problem that the relay contacts may be welded or have poor conduction, and it is strongly desired to avoid this problem.
Furthermore, in the motor control circuit using the relay,
It has drawbacks such that the abnormality detection circuit is generally complicated and the rotation speed of the motor cannot be controlled. The reason why the abnormality detection circuit becomes complicated is that it is necessary to detect the correspondence between the current flowing through the relay coil and the current flowing through the relay contact in order to detect welding and conduction failure of the relay contact. Fig. 15 shows the rotation speed of the motor.
As shown in (4), it is determined only by the drive power source B _M of the motor.

On the other hand, in a motor control circuit using a semiconductor as shown in FIG. 16, although there is no problem such as welding of relay contacts, it is more expensive than a motor control circuit using a relay. It has drawbacks such as a large mounting area and a large weight. The motor used for adjusting the position of the electric seat generally has a drive current of about several tens of amperes. In this level of current control, semiconductors are actually more expensive than relays. In addition, if the semiconductor controls the current of this level, it is naturally necessary to provide a heat radiating plate, and its mounting space becomes larger than that of a relay.
Further, since a heat sink is required, its weight becomes heavy.

Further, in the conventional control of the movable portion of the electric seat as shown in FIG. 17, a rapid acceleration is generated at the start or end of the movement of the movable portion. This sudden acceleration gives a user discomfort due to a shock, and improvement has been desired.

The technical problem of the present invention is to pay attention to such a problem and to avoid the welding of the relay contact and to detect the abnormality while lowering the cost and occupying a smaller mounting area than the case where all are made of semiconductor. It is to realize a motor control circuit which is easy and can also control the speed of the motor. Another object is to use such a motor control circuit for an electric seat to eliminate discomfort caused by a sudden acceleration of a movable part.

[0011]

FIG. 1 is a circuit diagram for explaining the basic principle of the motor control circuit according to the first aspect. Motor M ₁ ~M _N is a motor controlled by the motor control circuit according to the present invention. Each motor M ₁ ~M _N, to connect the forward and reverse switches SW ₁ to SW _N that determines the direction of rotation of the motors, respectively. Forward / reverse switches SW _{1 to} S
W _N is composed of relays RL _a and RL _b . The semiconductor TR1 which controls the speed of the motor, forward and reverse switch SW ₁ to S
Connect to W _N in common.

Forward / reverse switch SW₁~ SW_NThe components that make up
Ray RL_a, RL_bHave their relay contacts exclusively
By switching to the ON side and the OFF side, the motor M₁~ M_N
Reverse the direction of the current flowing through. Such a forward and reverse switch
Ji SW₁~ SW_NAnd motor M ₁~ M_NCurrent flow formed by
In the road, the semiconductor TR1 is connected to the motor M₁~ M_NFlow to
Control the current.

FIG. 2 is a circuit diagram for explaining the basic principle of the motor control circuit according to the second aspect. Motor M ₁ ~M _N is a motor controlled by the motor control circuit according to the present invention. The relay RL _C1 ~RL _CN that the forward and reverse switch SW ₁ selects a connection between the motor M ₁ ~M _N, the motors M ₁ ~
Connect to _MN respectively. The forward / reverse switch SW ₁ that determines the rotation direction of the motor is commonly connected to the relays RL _{C1 to} RL _CN . Set the forward / reverse switch SW ₁ to the relays RL _a and RL.
It consists of _b . Semiconductor TR1 that controls the speed of the motor
Is connected to the forward / reverse switch SW ₁ .

A relay RL constituting the forward / reverse switch SW _1.
The relay contacts of _a and RL _b are exclusively switched between the ON side and the OFF side, so that the directions of the currents flowing through the motors M _{1 to MN} are reversed. Such a forward / reverse switch S
In the current path formed by W ₁ , the relays RL _{C1 to} RL _CN , and the motors M _{1 to MN} , the semiconductor TR1 is connected to the motor M.
Controls the current flowing from _{1 to MN} .

According to a third aspect of the present invention, the circuit for controlling the motor of the movable portion of the electric seat has the first or second aspect.
The motor control circuit is used.

[0016]

FIG. 3 illustrates the principle diagram of claim 1 shown in FIG.
It is a time chart. Here, the kth motor M_k
To rotate forward. Forward / reverse switching signal as shown in Fig. 3 (a)
SG_kOf the coil current S2. This allows the forward and reverse
Switch SW_kRelay RL _aIs as shown in (b) of the figure.
After chattering, it switches to the ON side. Tsuma
Motor M_kIs the forward / reverse switch SW_kRelay RL_a
To the semiconductor TR1. At this time, the relay
RL_aCauses chattering, as shown in Fig. 6 (c).
In addition, the semiconductor TR1 is off during the chattering period.
No current flows through the relay contacts. As a result, due to discharge
No welding of relay contacts occurs.

After a necessary and sufficient time for ending the chattering, the motor drive control signal S1 (on / off signal of the semiconductor TR1) is added as shown in FIGS.
The motor drive control signal S1 is a rectangular wave. If the duty ratio is small as shown in (d), the motor rotates at a relatively low speed as shown in (f) in the figure, and the duty ratio should be large as shown in (e). For example, the motor rotates at a relatively high speed as shown in Fig. 6 (g). That is, the motor speed can be controlled by changing the duty ratio of the motor drive control signal S1.

After turning off the semiconductor TR1 as shown in FIG. 3 (h), the coil current S2 of the forward / reverse switching signal SG _k is cut off. As a result, the relay RL _a of the forward / reverse switch SW _k becomes
After chattering for a while like (i), OF
Switch to F side. At this time, the relay RL _a causes chattering, but as shown in (j) of the figure, since the semiconductor TR1 is off during the chattering period, no current flows through the relay contact. As a result, welding and wear of the relay contacts due to discharge do not occur.

Next, assume that the k-th motor M _k is rotated in the reverse direction. As shown in FIG. 3 (k), the coil current S3 of the forward / reverse switching signal SG _k is passed. Accordingly, the relay RL _b of the forward and reverse switch SW _k is switched to the ON side after causing a while chattering as shown in FIG. (L). That is, the motor M _k
Is connected to the semiconductor TR1 via the relay RL _b of the forward / reverse switch SW _k so that the current flows in the opposite direction to the forward rotation. At this time, the relay RL _b causes chattering, but as shown in (m) of the figure, since the semiconductor TR1 is off during the chattering period, no current flows through the relay contact. As a result, welding and wear of the relay contacts due to discharge do not occur.

After a necessary and sufficient time for ending the chattering, the motor drive control signal S1 is added as shown in FIGS. The motor drive control signal S1 is a rectangular wave, and if the duty ratio is small as shown in (n), the same figure (p)
The motor rotates at a relatively low speed as shown in Fig. 6A, and if the duty ratio is large as shown in Fig. 2 (o), the motor rotates at a relatively high speed as shown in Fig. 1 (q). That is, the motor speed can be controlled by changing the duty ratio of the motor drive control signal S1.

After turning off the semiconductor TR1 as shown in FIG. 3 (r), the coil current S3 of the forward / reverse switching signal SG _k is cut off. As a result, the relay RL _b of the forward / reverse switch SW _k becomes
After chattering for a while like (s), OF
Switch to F side. At this time, the relay RL _b causes chattering, but as shown in (t) of the figure, since the semiconductor TR1 is off during the chattering period, no current flows through the relay contact. As a result, welding and wear of the relay contacts due to discharge do not occur.

FIG. 4 is a time chart for explaining the principle diagram of claim 2 shown in FIG. The control of the rotation direction and the rotation speed of the motor is the same as the principle of claim 1. here,
It is assumed that the _kth motor M _k is rotated. Figure 3 flow coil current H _k of the motor select signals as (u). As a result, the relay RL _Ck switches to the ON side after chattering for a while as shown in FIG.

Further, as shown in FIG. 3 (a), the forward / reverse switching signal SG
₁Of the coil current S2 or S3. This makes it positive
Reverse switch SW₁Relay RL_aOr RL_bIs the same figure
ON after chattering for a while as in (b)
Switch to the side. That is, the motor M_kIs the forward / reverse switch S
W₁Relay RL_aOr RL_bAnd the relay RL_CkThrough
Then, it is connected to the semiconductor TR1. At this time, the forward / reverse switch
Ji SW₁Relay RL _aOr RL_bAnd relay RL_CkIs
Chattering occurs, but as shown in (c) of the figure,
Since the semiconductor TR1 is off during the turning period, the relay
-No current flows through the contacts. As a result, the relay due to discharge
No contact welding or wear occurs.

After turning off the semiconductor TR1 as shown in FIG. 3 (w), the coil current H _k of the motor selection signal is cut off. As a result, the relay RL _Ck switches to the OFF side after chattering for a while as shown in (x) of the figure. Further, as shown in FIG. 3 (h), the coil current S2 or S3 of the forward / reverse switching signal SG ₁ is cut off. As a result, the relay RL _a or RL _b of the forward / reverse switch SW ₁ switches to the OFF side after chattering for a while as shown in FIG. At this time, the relay RL _a or RL _{b of the} forward / reverse switch SW ₁
And the relay RL _Ck cause chattering, but as shown in FIG. 9 (j), since the semiconductor TR1 is off during the chattering period, no current flows through the relay contact. as a result,
No welding or wear of relay contacts due to discharge.

In a conventional motor control circuit using semiconductors, 4 × N semiconductors are required for N motors. On the other hand, as shown in FIGS. 1 and 2, in the present invention, the required number of semiconductors does not depend on the number of motors and is always one, and a low-cost relay is used instead of a high-cost semiconductor. I'm using it. As a result, the cost is lower than when all the semiconductors are used. In addition, since only one semiconductor is required, the mounting space for the heat sink is smaller than that for all semiconductors. It also reduces the weight because it requires less heat sinks.

Further, since welding of the relay contacts does not occur,
The failure mode of the relay is limited, and its abnormality detection becomes easier than in the case where welding may occur. As for the semiconductor, since the temperature detecting means can be incorporated inside the semiconductor package, if the high temperature is detected by using the temperature detecting means, the abnormality can be easily detected.

1 and 2, the rotation speed of the motor is changed by changing the duty ratio of the motor drive control signal S1. As in claim 3, the motor control circuit of the present invention is used for the electric seat, and the motor drive control signal S is used.
If the duty ratio of 1 is gradually changed, it is possible to avoid a sudden acceleration occurring in the movable part. In this way, controlling the duty ratio of the motor drive control signal S1 to change the speed of the motor is referred to as "PWM (Pulse
Width Modulation) control ”.

[0028]

EXAMPLES Next, examples of practical use of the motor control circuit according to the present invention will be described. FIG. 5 is a block diagram showing an embodiment of claim 1. The relays RL51 and RL52 form the forward / reverse switch SW ₁ of FIG. The FET 57 corresponds to the semiconductor TR1 of FIG. The relays RL51, RL52, and FET57 are respectively the FET drive circuit 53, the relay drive circuits 54, 55, and the I / O unit.
It is controlled by the microcomputer 51 via 52. The control switch 56 is a switch for instructing the operation of the motor M51, and the microcomputer 51 inputs the operation instruction via the I / O unit 52.

FIG. 6 is a flowchart of motor control performed by the microcomputer 51. When the control switch 56 is operated to instruct the normal rotation of the motor, the microcomputer 51 instructs the motor M51 from the ON-side contact of the relay RL51 to the O of the relay RL52 as in steps F61 to F64.
Set a current path to the FF side contact, and relay them RL51,
Wait until the chattering of RL52 is complete. At this time,
Since FET57 is turned off by step F62,
The relay contacts do not weld or wear. After that, step F65
As described above, the motor M51 is rotated by the PWM control.

When the control switch 56 is operated to instruct the reverse rotation of the motor, the microcomputer 51 causes the step F
66 to F69, the motor M51
A current path from the ON contact of the relay RL52 to the OFF contact of the relay RL51.
1. Wait until the chattering of RL52 is completed. At this time, since the FET 57 is turned off in step F67, the relay contact is not welded. After that, step F610
As described above, the motor M51 is rotated by the PWM control.

FIG. 7 is a block diagram showing an embodiment of claim 2. In FIG. The relays RL71 and RL72 form the forward / reverse switch SW ₁ of FIG. Relay RL73, RL74, RL75
Corresponds to the relays RL _{C1 to} RL _CN in FIG. FET71
0 corresponds to the semiconductor TR1 in FIG. Those, relay RL71, RL72, RL73, RL74, RL75, and FET
57 is a FET drive circuit 73 and a relay drive circuit 7 respectively
It is controlled by the microcomputer 71 via 4, 75, 76, 77, 78 and the I / O unit 72. The control switch 79 is a switch for instructing the operation of the motors M71 to M73, and the microcomputer 71 inputs the operation instruction via the I / O unit 72.

FIG. 8 is a flow chart of the motor control performed by the microcomputer 71, and the rotational direction / speed control part is the same as the flow chart of claim 1.
When the control switch 79 is operated to instruct the rotation of the motor M71, the microcomputer 71 provides a current path only to the motor M71 via the RL73 as in steps F82 to F83. At this time, according to step F82, FET710
Is off, so the relay contacts do not weld or wear.

Similarly, when the control switch 79 is operated to instruct the rotation of the motor M72, the microcomputer 71
As in steps F84 to F85, the motor M is passed through the RL74.
When a current path is provided only for 72 and the control switch 79 is operated to instruct rotation of the motor M73, the microcomputer 71 causes only the current path for the motor M73 via the RL75 as in steps F86 to F87. To provide. At this time, in any case, since the FET 710 is turned off in step F84 or step F86, the relay contact is not welded or worn.

FIG. 9 is a block diagram showing an embodiment of claim 3. The electric seat 910 has one or more movable parts, and these movable parts are moved by one or more motors. The motor control circuit 98 is the motor control circuit according to claim 1 or 2. The semiconductor constituting the motor control circuit 98 of the present invention is controlled by the microcomputer 91 via the FET drive circuit 94 and the I / O unit 92. Similarly, the relay that constitutes the motor control circuit 98 of the present invention is a relay drive circuit.
It is controlled by the microcomputer 91 via the I / O unit 92 and the I / O unit 92.

The reproduction position memory 93 stores reproduction position data (1) to (N) as a result of the position adjustment of the electric seat, and the microcomputer 91 can read the reproduction position data. For example, the reproduction position data (1) is the position of each movable part of the electric seat that the user A prefers, and the reproduction position data (2) is the position of each movable part of the electric seat that the user B prefers.

The manual control switch 96 is used for manually instructing the position adjustment of the electric seat, and the microcomputer 91 inputs the operation instruction through the I / O unit 92. The reproduction switch 97 is for operating and instructing the position adjustment of the electric seat in accordance with the reproduction position data stored in the reproduction position memory 93.
Inputs its operation instruction via the I / O unit 92. Further, these inputs may be input by an external signal such as serial communication.

When the manual control switch 96 is operated to start the position adjustment, the microcomputer 91 determines that the FET
Through the drive circuit 94 and the motor control circuit 98, the motor 99
Is PWM controlled. At this time, the duty ratio in the PWM control is gradually increased so that the acceleration of the movable portion of the electric seat does not suddenly change, as shown in FIG. 10 (a). When the manual control switch 96 is operated to stop the position adjustment, the microcomputer 91 immediately stops the motor 99 as shown in FIG. 10 (b). This is to make the stop position in the position adjustment accurate, and in this case, the user does not feel uncomfortable.

When the position adjustment is started by operating the reproduction switch 97, the microcomputer 91 determines that the FET drive circuit 9
4, PWM the motor 99 via the motor control circuit 98
Control. At this time, the duty ratio in the PWM control is gradually increased so that the acceleration of the movable portion of the electric seat does not change abruptly, as shown in FIG. 11 (a). When the movable part approaches the position indicated by the reproduction position data (i) stored in the reproduction position memory, the microcomputer 91 causes the PW
The duty ratio in M control is gradually reduced,
As shown in (b), stop the acceleration of the movable part of the electric seat so that the acceleration does not change suddenly.

12, 13 and 14 show examples of duty ratio control in PWM control. In FIG. 12, the pulse period is fixed and the pulse width is changed. In FIG. 13, the FE is turned off by keeping the FET off time constant.
The time to turn on T is changing. In FIG. 14, the time when the FET is turned on is fixed and the time when the FET is turned off is changed. As a matter of course, the duty ratio may be changed by appropriately combining these.

[0040]

As described above, according to the present invention, in the motor control circuit for controlling one or more motors, the rotation direction of the motor is selected by the mechanical contact relay and the rotation speed of the motor is controlled by the semiconductor. Therefore, it is possible to avoid welding of the relay contacts, and it is possible to control the rotation speed of the motor by PWM control with one semiconductor regardless of the number of motors to be controlled. As a result, the space devoted to heat dissipation from the semiconductor could be reduced and the failure modes of the relay could be limited.

Therefore, according to the present invention, it is possible to avoid the welding of the relay contacts, to easily detect the abnormality, and to reduce the speed of the motor, while the cost is lower than that of the semiconductor device and the mounting area is small. A controllable motor control circuit is now possible. Further, by using such a motor control circuit in the electric seat, it is possible to eliminate the discomfort caused by the sudden acceleration of the movable portion.

[Brief description of drawings]

FIG. 1 is a principle view of claim 1.

FIG. 2 is a principle view of claim 2;

FIG. 3 is a time chart of claim 1.

FIG. 4 is a time chart of claim 2.

FIG. 5 is an embodiment of claim 1.

FIG. 6 is a flowchart in the embodiment of claim 1.

FIG. 7 is an embodiment of claim 2;

FIG. 8 is a flowchart in the embodiment of claim 2;

FIG. 9 is an embodiment of claim 3;

FIG. 10 is a time chart showing an example of speed control during manual control.

FIG. 11 is a time chart showing an example of speed control during reproduction.

FIG. 12 is a time chart showing a first example of ON / OFF waveforms of FETs.

FIG. 13 is a time chart showing a second example of ON / OFF waveforms of FETs.

FIG. 14 is a time chart showing a third example of ON / OFF waveforms of FETs.

FIG. 15 is a conventional example of a motor control circuit using a relay.

FIG. 16 is a conventional example of a motor control circuit using a semiconductor.

FIG. 17 is a time chart showing a conventional example of the moving speed of the movable portion of the electric seat.

[Explanation of symbols]

TR1 semiconductor SW ₁ to SW _N normal and reverse switch M ₁ ~M _N motor RL _C1 ~RL _CN relay RL _a, RL _b relay S1 motor drive control signal constituting the forward and reverse switch SG ₁ to SG _N Seigyakusetsu signal H ₁ ~ H _N Motor selection signal

Claims (3)

[Claims] 1. A one or more motors relates to a motor control circuit for controlling the (M ₁ ~M _N), forward and reverse switch for determining the direction of rotation of the motors _{(M 1 ~M N) (SW} 1 ~SW N) Through the respective relays (RL _a , RL _b ) and the forward / reverse switches (SW _{1 to} SW _N ) that make up each motor (M
A motor control circuit comprising: a semiconductor (TR1) for controlling a driving current of _{1 to MN} ). 2. A motor control circuit for controlling one or more motors (M _{1 to MN} ), comprising a forward / reverse switch (SW ₁ ) for determining the rotation directions of all the motors (M _{1 to MN} ). Relay (RL _a , R
And L _b), a relay to determine the respective connection between the motor and the forward and reverse switch _{(SW 1) (M 1 ~M} N) (RL C1 ~RL CN)
And the forward / reverse switch (SW ₁ ) and the relay (RL _C1 ~
RL _CN) via a motor control circuit, characterized in that it comprises a semiconductor (TR1), the controlling the driving current of the motors (M ₁ ~M _N). 3. An electric seat having one or more movable parts, wherein the movable parts are moved by one or more motors, wherein the motor control circuit comprises the motor control circuit according to claim 1 or 2. An electric seat, which is configured by a circuit.