JPS62118794A - Controller for driving motor - Google Patents

Abstract

PURPOSE:To always supply a proper driving current to a motor even when necessary torque difference at accelerating, decelerating time and low speed time or stopping time is large by programming the operating mode of the motor and controlling a driving current in response to the mode. CONSTITUTION:A sequence controller 1 outputs signals CW/CCW, phiOFF, RESET at predetermined timing to generate a predetermined pulse from a pulse generator 2, to control driving currents from drivers 5A-5E and to control a motor SM. A current setter 4 alters the output states of signals D0-D2 to selectively alter the voltage VSET of the signal ISET, thereby selectively varying a driving current to be supplied to the motor SM.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a motor drive control device, for example, a motor used in a scanner such as a copying machine, for acceleration operation, deceleration operation,
The present invention relates only to a motor drive control device that can perform low-speed operation in good condition.

[Conventional technology]

As is well known, when an object is moved by a motor, the inertia and frictional force differ depending on the state of motion of the object, so the torque required from the motor also varies accordingly. For example, the torque required of the motor (hereinafter referred to as "required torque") is greater during acceleration and deceleration than when the object is stationary or in low-speed motion. This is particularly noticeable when providing a steep rate of curing. (However, since friction provides a braking effect during deceleration, the required torque is not necessarily greater than at low speeds or when stopped.) In this way, the required torque changes depending on the state of motion of the object, so the rotation speed Synchronous motors (e.g. stepping motors) that are controlled by the frequency of synchronous pulse signals may experience delays or overshoots during acceleration.
Vibrations occur during deceleration and stopping, and problems such as shifting of the stopping position occur. This problem becomes more pronounced as the inertia of the load applied to the motor increases, and is likely to occur when the output torque of the motor is not sufficient for the maximum required torque.

Therefore, in order to prevent the above-mentioned problems from occurring, the motor and drive circuit used should be ones that can output at least the maximum required torque, and the drive circuit should always supply a constant drive current to the motor. It had become. Furthermore, when changing the drive current to perform torque control, a variable resistor for current control is used and this is manually adjusted in advance before driving the motor.

[Problem that the invention seeks to solve]

However, the maximum required torque occurs during acceleration and deceleration, and this time is generally shorter than at low speeds, so the drive current from the motor drive circuit is adjusted to the maximum required torque. If set, the motor torque due to the motor drive current will be fully utilized during this short period of time, but at other times, more drive current than necessary will be supplied to the motor, resulting in poor efficiency and increased heat generation. The problem was that there were many. In particular, the above problem becomes noticeable when the motor is suddenly started up or stopped down.

The present invention was made in view of the above-mentioned problems, and an object of the present invention is to provide a motor drive device that can always supply an appropriate drive current to the motor and drive the motor efficiently.

[Structure of the invention]

The motor drive control device of the present invention includes a current supply means for supplying a drive current to the motor, and a control means for programming the operating mode of the motor and controlling the drive current according to the operating mode. .

[Effect]

In this invention, the control means programs the operating mode of the motor and controls the drive current according to the operating mode. Even when there is a large difference in the required torque between the motor and the motor at low speed or at a standstill, it is possible to always supply the appropriate drive current to the motor, making it possible to drive the motor efficiently and properly. Heat generation is also minimized.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 1O.

FIG. 1 is a block diagram showing the overall configuration of a first embodiment of the present invention. In FIG.
is a sequence controller that controls the operation timing of various circuits to be described later, and is composed of a CPU, memory, I10 port, timer, etc. 2 is the signal cw/ccw from the sequence controller l, the signal $OFF,
A pulse generator 3 generates pulses φA to φE in synchronization with the clock signal CLK based on the signal RESET 2, and a PWM device 3 generates a current chopper pulse signal CHP for driving the stepping motor SN at a constant current. As shown in FIG. 2, operational amplifiers DPI, OP2.
A triangular wave generator 0. consisting of an oscillator O8C, a resistor Rt and a capacitor Ct. Transistors TR21 to TR23,
It is composed of resistors R21 to R25, capacitors C21 and C22, and the like. In this configuration, the reference signal l5E
T is connected to the inverting input terminal of operational amplifier OP1 via capacitor C21 and resistor R21, and also to the monitor signal IMO.
N are respectively input to the non-inverting input terminals of the operational amplifier OPI, and the chopper pulse signal CHP is taken out from the collector of the transistor TR23.

4 is a sequence controller 51 that controls the voltage level of a reference signal l5ET that controls the pulse width of the chopper signal CHP.
Signals ID0WN, D o , D 1 ,
A current setting device that determines based on D2, transistors TR31 to TR34 and variable resistor R3 as shown in FIG.
1-R3[1, etc.]. In this configuration, the signals DO, DI, and D2 are connected to transistors TR31, TR32, and TR33, respectively;
00 and N are respectively input to the transistor TR34,
A reference signal l5ET is taken out from the collectors of transistors TR31 to TR33. Note that one or more sequence controllers 1, pulse generators 2. The PWM device 3 and the current setting device 4 constitute a control means. Further, 5A to 5E are driver circuits serving as means for supplying drive current to the Stellar pin motor SN based on the signals GHP and φA to φE, and here, as shown in FIG. is applied.

Next, the operation of each of the above circuits will be explained.

The sequence controller 1 receives a signal C%1/CCV,
By outputting φOFF and RESET at a predetermined timing, the pulse generator 2 generates a predetermined pulse, controls the drive current from the driver circuits 5A to 5E, and controls the motor SM. That is, the pulse generator 2 controls the rotational direction of the motor SM as shown in Table 1 according to the signal cw/ccw output from the sequence controller l.

Table 1 Changes in phase signals I: rHJ active 0: rLJ non-active Also, when the φOFF signal becomes active (L: low level), all the signals from the pulse generator 2 become non-active "L", and the driver circuits 5A- 5E M, f
N does not flow and the motor SM is in a free state. Also,
When the signal RESET is output, the pulse generator 2 receives it and sets the states of the transmission signals φA to φi to the state of step 0 in Table 1. Furthermore, the clock CLK signal sequentially switches the steps in the rotation direction as shown in Table 1 at the rising edge (or falling edge) of the signal. In this embodiment, the pulse generator 2 performs four-layer excitation. Although the method described above has been described, it is also possible to apply other methods.

Further, the driver circuits 5A to 5E supply a drive current to the motor SM in accordance with the chopper signal CHP from the device 3 to the phase signals φA to φi and Pw from the pulse generator N2. The operation will be explained below based on the configuration shown in FIG.

As shown in Table 1, in step O, the phase signal φA is active "H", so transistors TR47 and TR48 are
It becomes N. Further, the transistor TR42 is turned OFF and ON in accordance with the ON and OFF states of the transistor TR41. Here, transistor TR41 chopper signal CHP
When rHJ is active, it is turned OFF, and when it is non-active "L", it is turned ON. At this time,
Since the phase signal φA is non-active "L", transistors TR43 and TR44 are turned off, and transistor TR4 is turned off regardless of whether transistor TR45 is turned on or off.
8 is set to OFF. Therefore, the chopper pulse signal OH
When P is active rHJ, the potential of output terminal A is set to "H" state, the potential of output terminal A is set to "L" state, and current flows in the direction of A from output terminal A via motor SM. . Furthermore, when the signal CHP is inactive rLJ, the output terminal A is brought into a high impedance state (at this time, A is in the L state), and the supply of drive current to the motor SM is cut off. In addition, as shown in step 2, the phase signal φA is inactive "L", and φA is active "H".
In this case, contrary to the above case, the pulse signal C for chisel collar is
When HP is in the rHJ state, a drive current in the A direction flows through the motor SM from the output terminal λ. (Note that when the pulse signal CHP for chisel collar is in the rLJ state, the output terminal A is set to a high impedance state, and the supply of drive current to the motor SM is cut off. In addition, as shown in step 6, the phase signal φA
When both are inactive rlJ, the transistors TR42 and TR are activated regardless of the chopper pulse signal CHP.
43, TR44゜TR4B, TR47, TR48 OF
F, and output terminals A and A are both placed in a high impedance state to cut off the supply of drive current to motor SM.

Note that the pulse generator 2 prohibits both phase signals A and φA from becoming active "H". In this way, supply of drive current to each phase of motor SM,
r of the potential of the output terminals A and A that determines the cutoff and direction
LJ and rHJ (high impedance) are expressed by the AND of the phase signals φA and φ and the signal CHP. However, the output terminal A is "L".

The labels of "H" are not constant.

Although the operation of the driver 5A has been described above, the other drivers 5B to 5E also perform similar operations according to the phase signals φB to φi.

Next, the operation of the 2% 1M device 3 that generates the signal CHP will be explained. As shown in FIG. 2, a signal lN0N is input to the non-inverting input terminal of the operational amplifier OPI. This signal lN0N is supplied via a resistor Ri having a higher resistance value than the resistor R[+] for detecting the current i flowing through the motor SM and flowing from the drivers 5A to 5E toward the ground, as shown in FIG. Ru. Furthermore, a signal ISE is input to the inverting input terminal of the operational amplifier OP1 via a resistor R21. Here, the voltage level of signal l5ET is set to V
set, and the voltage level of the signal lN0N is VMON, the output voltage vP1 of the operational amplifier OPI is ideally VP, = (VMON-VSET) -R22/R2
1... (Equation 1) and is input to the inverting input terminal of the operational amplifier OP2.

In addition, a triangular wave voltage vO from the triangular wave generator 0 (see FIG. 6(b)) is applied to the non-inverting input terminal of the operational amplifier OP2.
is input, and in operational amplifier OP2, this voltage vO
and the output voltage VPI, and if vPl>vO, the output voltage vP2 becomes rLJ. Also VP
If I<VO, vp2 becomes "H" (Fig. 6 (G
) Here, if the output voltage vP2 is low level, transistors TR21 and TR22 are turned off.
, ) At the same time as transistor TR23 turns ON, chopper pulse signal CHP becomes “L” (non-active)
On the other hand, when the output voltage vP2 is at a high level, the transistors TR21 and TR22 are turned on.
, TR23 is turned off, so the chopper pulse signal CHP is in a high impedance state.

However, as shown in FIG. 2, this signal CHP is
Since it is pulled up to cc 1, it is actually “H” (
active state), so as shown in FIG.
During MON<VSET, chopper pulse signal C)
The IP is always in an active state (hereinafter, this state is referred to as the initial active state), and when VMON > VSET, that is, after reaching VSET, the IP becomes "H".
” (active) state and “L” (non-active)
This chopper pulse signal CHP, which repeats the state and state, is input to the driver circuits 5A to 5E as described above,
The current supplied from the driver circuit 5A to the motor SM is brought close to a certain value. Here, the frequency of the triangular wave voltage needs to be sufficiently larger than the frequency of the clock signal GLK. Then, the signal l5ET(7) voltage is changed from VSET to VS
ET' (assuming vSET <VSET'), the input voltage VP to the inverting input terminal of operational amplifier op2
+ drops to voltage vp+', and output voltage vp2 becomes vp2
' (See Figure 6(d)). As shown in the figure, this vp2' has an initial active state of said vP2'.
, the chopper pulse signal CHP also becomes longer, and the drive current i supplied from the drivers 5A to 5E to the motor SM increases, (i = VMON/RIB),
f) After that, rHJ, rLJ of output voltage vp2'
By repeating this, the current stabilizes on average at a certain value. In this way, by controlling the voltage VSET of the signal l5ET within a certain range, it is possible to control the current value to be supplied to the motor SM.

Next, the operation of the current setting device 4 that controls the voltage VSET of the signal 15ET will be explained.

Transistors TR31, TR32, and TR33 output signals Do and DB from the sequence controller 1.
.

When D2 is "L" (active), each turns on, and the transistor TR34 receives the signal l11011.
Turns ON when JN is "H" (active).

Here signals Do, D+, D2 and signal l110WN
are all rH4, and transistors TR31 to TR32
are all OFF, the voltage VSET of signal l5ET is VSET-VCC2-R3B/(R35+R3B)...
(Equation 2) (However, the input impedance of the input terminal of the PWM device 3 to which the signal 15ET is input needs to be high.

) Also, when the signal Do becomes "L" (active) and the transistor TR31 is turned on, the voltage VSET' of the signal l5ET is as follows (Formula 3), which is lower than the voltage VSET. To increase. Here, I31
is the branch current flowing through R31, 131= (VCC2-VSET'-VCE)/R3
1... (Equation 4) where VCE is the saturated collector-emitter voltage of the transistor TR31.

Note that regardless of which of the signals DI and D2 is turned ON, the electrician 31 is connected to I32. as in the case where the signal Do is turned ON.
By replacing it with I33, it is possible to represent the voltage VSET. Also, if multiple signals become "L" (active) at the same time, the second term of (Equation 3) will be added. .

On the other hand, when the signal ID0WN becomes "H" (active) and the transistor TR34 is turned on.

Signal l5ET17) Voltage VSET' is...
...(Equation 5), and decreases compared to the voltage vsEy. Here, I34 is a branch current passing through resistor R34, and 134=(VS
ET"-VCE)/R34......(26
) becomes. However, the voltage VCE is the saturated collector-emitter voltage of the transistor TR34.

As described above, by changing the output state of the signal Do-D2, the voltage VSET of the signal l5ET can be selectively changed, and thereby the drive current to be supplied to the motor SH can be selectively changed. can. Note that each of the above-mentioned currents can be adjusted by adjusting the resistance values of variable resistors R31 to R2O. Also, signal D
If o, Dl, D2 and the signal OWN become active at the same time, the voltage of the signal l5ET that selects 1 becomes complicated. Therefore, in this embodiment, a logic circuit as shown in Fig. 5 is used to connect the sequence controller l and the current setting. By inserting it between the device 4, the above signals Do, Dl, D2 and ID0
WN is prohibited from becoming active at the same time.

Also, the voltage of the signal l5ET is changed to the signal Do, as described above.
Setting according to digital signals such as Dl, D2 and ID0WN is a kind of D/A conversion.

Therefore, the same operation can be performed by loading the sequence controller 1 with a D/A converter instead of the current setting device.

Next, a series of control operations will be explained with reference to FIG. 8 when the stepping motor SN performs so-called trapezoidal drive (see FIG. 7) in which the stepping motor SN goes from a stopped state through acceleration, constant speed, deceleration, and then to a stopped state. . In addition, in Fig. 7, (a)
shows the relationship between time (1) and speed V when trapezoidal drive is performed, (b) shows the relationship between time (1) and torque T, and (C) shows the relationship between time (1) and current I. The control flowchart shown in FIG. 8, which shows the relationships between the two, is programmed and stored in the ROM (7) in the sequence controller 1.

First, in 5TEPl, the motor SM is set to the initial state. That is, once the signal RESET is set to "L" (active), it is set to "H" again and each phase signal φA to φ
E to the state of step O (see Table 1), and the signal CW/C
CW indicates the rotation direction of motor SM, and signal ID0WN
is set to "H" (active), and the signal φOFF is set to "H".
(non-active) to stop current I to motor SM.
+ (see FIG. 7(c)) Next, when a command to drive the motor SM is output by a signal generated externally or inside the sequence controller 1, the signal I
Set D0WN to "L" and set signal Do-02 to flow acceleration current generator 4 (STEP 2). Then, while accelerating motor SH, clock signal CLK is not generated and 5TE is set.
P3) Based on this signal, it is determined whether a preset acceleration time has elapsed (STEP4),
When it is determined that the acceleration time has elapsed, the signal Do-02 is set to transmit the constant speed radio wave ■2, and the signal CLK is set.
is generated (STEP, 5.8). After this, it is determined whether or not the constant speed time has elapsed (STEP 7). When the low speed time has elapsed, the signal DO is activated to cause the deceleration electric current 3 to flow.
~D2 is set (5TEP8), the signal CLK is generated (STEP9), and it is determined whether the deceleration time has elapsed (STEPIO), and when the deceleration time has elapsed, the signal CLK is stopped (set to "H" state). ), and the signals Do, Dl to flow the signal 1 (stopping current I) with 10WN as rHJ.

Set D2 and maintain this state.

In this embodiment, the determination of 5TEP4, 7.10 is made by counting the falling or rising edges of the signal CLK, but it is made by measuring each elapsed time with a timer in the sequence controller 1. It is also possible. It is also possible to detect the rotational state of the motor SM using a rotary encoder or the like and control the drive current based on this.

Further, in the above embodiment, the drive current to be supplied to the motor SH is controlled by controlling the voltage of the 15ET signal input to the PWM device 3 using the signals Do, DI, and 02. It is also possible to control the drive current not only in the embodiment but also in other configurations.

For example, as shown in FIG. 9, the voltage VM of the signal ID0WN
ON 1/kO times, 1/k1 times, l/2 times, 3 times
A voltage changing circuit 6 that can be changed to double the voltage, etc. is provided, and the signal 1) IO
By selecting the voltage VMON of N in accordance with the signals Do, DI, and D2, it is also possible to control the panel width of the signal CHP and control the value of the drive current. In the drawings, the same or equivalent parts as in the above embodiment are given the same reference numerals.

Further, as shown in FIG. 10, the power supply voltage vccr is set to the signals vo, v1. Providing a power supply switching circuit 7 that switches according to v2 and thereby controlling the drive power supplied to the motor SM is also a rotation. In the drawings, the same or equivalent parts as in the above embodiment are given the same reference numerals.

Furthermore, by changing the state of the triangular wave shown in Figure 6, such as frequency, voltage level, bias voltage, waveform, etc.
It is also possible to control the drive current to the motor by changing the pulse width of the chopper pulse signal CHP, and the formula (
By controlling the ratio of R32/R31 in 1), the voltage V
It is also possible to control the drive current by controlling P3 and adjusting the pulse width of the signal CHP.

Furthermore, by increasing or decreasing the number of bits of the signal D o -D 2 that determines the value of the drive current, or by combining each signal, the current value can be set as finely as necessary.

Furthermore, in the above embodiment, all phases of the drive current are controlled by a single control means, but it is also possible to provide a control means for each phase and control the drive current independently. .

Further, in the above embodiment, the ffj1m operation of the motor was explained using trapezoidal drive, but the drive current can also be controlled for other operating modes.

〔Effect of the invention〕

As explained above, according to the present invention, since the drive current is controlled according to the operation mode of the block-formed motor, it is possible to Even when the required torque difference between speed and stop is large, it is possible to always supply the appropriate drive current to the motor, so the motor can be driven efficiently without consuming more current than necessary. This has the effect of minimizing heat generation due to drive current.

Furthermore, by programming the appropriate drive current settings, operability and accuracy are improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention, and FIG.
Figure 3 is a circuit diagram of the PWM device shown in Figure 1, Figure 3 is a circuit diagram of the current setting device shown in Figure 1, Figure 4 is a circuit diagram of the driver shown in Figure 1, Figure 5 is a configuration diagram of the signal manipulation logic circuit inserted between the sequence controller and the current setting device, and Figure 6 is the PW as seen in Figure 1.
A signal waveform diagram of each part in the M device, FIG. 7 is a diagram showing the trapezoidal driving state of the stepping motor, and FIG. 8 is a control flowchart for driving the stepping motor in a trapezoidal shape.
FIG. 9 is a block diagram showing a second embodiment of the present invention;
FIG. 0 is a block diagram showing a third embodiment of the present invention. 5A to 5E...Circuit diagram of the driver circuit power supply device as a current supply means Figure 3 Surface inspection for signal operation! Remains of the circuit (3) Figure 5 PWM step 1 Figure 7

Claims (2)

[Claims] (1) A motor drive characterized by comprising a current supply means for supplying a drive current to a motor, and a control means for programming the operating mode of the motor and controlling the drive current according to the operating mode. Control device. (2) The motor drive control device according to claim 1, wherein the control means controls the drive current according to the operation mode of the motor during acceleration, deceleration, and low speed.