JPS5879499A - Driving method for pulse motor - Google Patents

Abstract

PURPOSE:To smoothly continuously operate a pulse motor by suitably varying the phase of each exciting coil of the motor, thereby supplying a PWM wave. CONSTITUTION:PWM waves of different phases suitably obtained from the output terminals a'-d' of the output port 10 of a high frequency pulse generator 1 which is formed of a microprocessor are respectively inputted to the bases of drive transistors Ta-Td, an are supplied to the exciting coils 4, 5 of a pulse motor 2 through terminals a-d. A high frequency pulse generator 1 has an input port 6 which receives a command signal of the PWM wave output from the exterior and drives an arithmetic unit 7, an ROM8 which sets the program of generating the PWM wave and controlling and programming a player, an RAM9 of reading and writing various data and an output port 10.

Description

[Detailed description of the invention] The present invention relates to a method for driving a pulse motor.

Pulse motors have good starting and stopping responsiveness, so they can be used like servo motors, and in addition to being able to achieve ultra-low-speed synchronous rotation, unless the excitation current is turned off, a pulse motor generates torque to maintain its position when it is stationary. Because it has various characteristics, it is used in various drive sources.

For example, when used as a drive source for the pickup arm of a linear tracking player, the above characteristics will cause a certain reference position (for example, the rest position of the pickup arm).
On the other hand, by counting the number of pulses input to the pulse motor, the relative position of the pickup arm such as the lead-in position and return position of the record board can be detected without the need for a sensor.
However, this pulse motor only rotates intermittently as long as it is driven by Norculus input, and cannot provide continuous smooth rotation like a general DC motor or AC motor.
Therefore, as mentioned above, when the pulse motor is used as a drive source for the pickup arm, smooth performance cannot be expected. If it is something that was invented, a high frequency pulse that is sufficiently high compared to the highest pulse frequency that a pulse motor can follow is generated by a high frequency pulse generation circuit, and when it is input to the pulse motor, the alternating current of the excitation winding of the pulse motor is generated. Focusing on the fact that due to the influence of impedance, the current in the excitation winding becomes a current that is the average of high-frequency input pulses, we changed the excitation current to a sinusoidal current by appropriately changing the pulse width of the high-frequency pulses supplied to the pulse motor. This is intended to allow the pulse motor to operate smoothly and continuously.

That is, the PWM wave outputted from the high frequency pulse generation circuit (
By inputting a (Hulse width modulated wave) into the excitation winding of a pulse motor and performing two-phase excitation as a sinusoidal excitation current, the motor is intended to rotate smoothly like a general DC or AC motor.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an electrical circuit diagram showing an embodiment of a drive device that embodies the method for driving a pulse motor according to the present invention. Microprocessor as generation circuit 1
is used. Of course, it is not limited to this.
Any circuit that can obtain WM waves may be used.

2 is a four-phase pulse motor, 3 is its rotor, and 4 and 5 are excitation windings.

Ta to Td are drive transistors whose collector terminals are connected to the 10B terminal of a common constant voltage -φ voltage source, and whose emitter terminals are connected to terminals a to d of the excitation windings 4 and 5, respectively; The above-mentioned high frequency pulse generation circuit (hereinafter referred to as micropro sensor) 1 is connected to each pace terminal.
By receiving the PWM waves obtained from the output terminals a' to d' of the output port 10, the PWM waves are transmitted to the terminal a.
, b, c and d to the excitation winding.

Figures 2 (a) to 2) are output waveform diagrams provided to explain the driving state of the pulse motor 2, and representatively represent the a and b phases of the four phases of the pulse motor 2. (a) and (b) of the figure show the output terminal a+ of the output port 10 of the microprocessor-1.

b' shows the PWM waves output from (c) and (c).The PWM waves are input to the pulse motor 2 and shaped by the excitation windings 4 and 5 of the pulse motor 2. shows a sinusoidal excitation current.

If the excitation current is made into a sinusoidal waveform, the combined magnetic field will move between each phase a to 6 at a constant speed, and the movement of the magnetic field will cause the pulse motor 2 to rotate smoothly and continuously at a constant speed. Become. Furthermore, by using a sine wave, the magnitude of the magnetic field can also be made constant.

In addition, as shown in FIG. 2 above, in the drive system according to the present invention, the phases a to 6 of the pulse motor 2 are shifted by 90° intervals, and in each phase, as shown in FIG. (stomach)
As shown in FIG. A pulse with a pulse width of pHP21
One each of Pa+... appears. Of course,
As shown in FIGS. 2(a) and 2(b), one pulse may have multiple pulse periods t.

Next, regarding the microprocessor, the microprocessor 1 receives an external PWM wave output command signal and has an input port for driving the arithmetic unit 7, a PWM wave generation program, a player control program, etc. It consists of a ROM (read only memory) 8 for setting the data, a RAM (random access memory) 9 for reading and writing individual data, and the above-mentioned output port 10. The arithmetic unit 7 includes a clock pulse oscillator (hereinafter referred to as O8C) 11 which outputs clock pulses of a constant period according to instructions from the ROM 8, and a clock pulse oscillator (hereinafter referred to as O8C) which outputs clock pulses of a constant period according to the instructions from the RAM 9 corresponding to each of the phases a to C. A pulse width that is preset with information (i.e., a predetermined pulse width value) regarding the given pulse width (pulse width of each pulse in the PWM wave) and remains set until a new pulse width value is given from the RAM again. Setting devices (for example, presettable counters) 12a to 12
d, and a game which is also provided corresponding to each of the above-mentioned phases a to d and which opens and closes according to the program in ROM 8)
A pulse period setting counter 14 that repeatedly counts the clock pulses given from the 08C11 through the pulse period 13a to 13dk for a time equivalent to the pulse period t.
a to 14d, and the pulse width setters 12a to 12d.
and D/A converters 15 to 22 that convert the logic signals obtained from the pulse period setting counters 14a to 14d into analog signals, and the pulse width setting devices 12a to 12d obtained through all of these D/A i converters. The signals from the pulse period setting counters 14a to 14d, that is, the above-mentioned predetermined pulse width value, are compared with the count value of the pulse period setting counter, and the first pulse of the former is larger than the value of the latter. It is composed of comparators 23a to 23d that output one pulse.

The present invention has a diagonal configuration fzc, and its operation will now be described with reference to the flowchart shown in FIG.

Incidentally, this flowchart shows the operation of the microprocessor 1 which outputs a PWM wave of one phase.

Now, when a command signal for outputting a PWM wave is given to the input port of the microprocessor-1 through the input terminal 24 by turning on the power switch, etc., the microprocessor-1
5 means "start", and at this instant, RO, M8
According to the program, "pulse non-use period is released", the pulse width setter (for example, 12a corresponding to the a phase) and the pulse period setting counter (similarly a
814a) corresponding to the phase are set to a ``predetermined pulse width value'' and an ``initial value'', respectively.

That is, for example, the first pulse P of the PWM wave in the a phase
If the pulse width of the pulse P1 is equivalent to the 20 clock pulses, the pulse width setter 12a stores a predetermined pulse width value of the pulse P in the RAMQ according to the program in the ROM8. A predetermined pulse width value "2o" is transferred from the first stage of the memory, and the pulse width setter 12a supplies the predetermined pulse width value r20J to the comparator 23a via the D/A converter 19.

Further, the pulse period setting counter 14a is set to an initial value, ie, "o" by the program in the ROM 8.

Note that if this counter 14a (41 pulse period t corresponds to the time length of 100 clock pulses) counts 100 clock pulses, it returns to "0" (initial value) again, and this process is repeated. .

Now, as described above, when the pulse width setter 12a and the pulse period setting counter 14a are set to the "predetermined pulse width value" and the "initial value" respectively, the pulse period setting counter 141L is given from 08C11 via the gate 13at. Count the clock pulses and count up (this is the item ``Pulse period setting counter count up'' in the flowchart).

Then, as the count-up is executed, the comparator 23a compares whether the count value of the pulse period setting counter 14a is larger or smaller than the predetermined pulse width value "20" of the pulse width setting device 12a (see the figure in the flowchart). Comparison of small and large items).

And the former is smaller than the latter, that is, NO'7'.
The comparator 23a continues to output a signal at a constant voltage level (C'output port ON'), and the former is more active than the latter.
That is, if Yes, the comparator 23a stops outputting the signal at the constant voltage level (''output port Q
FF") o At this stage, one pulse P of the above PWM wave
is formed, and is sent to the a terminal of the excitation winding 5 of the pulse motor 2, that is, the a phase, via the driving transistor Ta.

Subsequently, the pulse period setting counter 14a generates a clock pulse 1rloOj corresponding to one pulse period.

When it finishes counting, it returns to 0 again, that is, it returns to the initial value.
do.

Then, the ROM 8 determines whether or not it is necessary to change the pulse width of the next pulse to be output according to a predetermined program, and if it is not necessary (NO), the pulse width setter 12a'ir changes the predetermined pulse width value again. At the same time, the pulse period setting counter 14a is set to the initial value "0". That is, the process returns to the position (3) in the flowchart.

If it is necessary (Yes), then it is determined whether the above pulse width needs to be increased or not, and if it is Yes, the RAM
9, the pulse width setter 12a selects a pulse whose pulse width is one step shorter than the previous pulse (the above-mentioned pulse P1) (P2 in this example).
After that, the comparator 23a is caused to output the pulse P2.

Also, if it is determined that the above-mentioned pulse width is necessary for Runo JO (No), then ROM8 is set to pulse width setter 1 from RAM9.
2a is supplied with a predetermined pulse width value of a pulse whose pulse width is one step smaller than the previous pulse.

At this time, it is difficult to judge whether the new predetermined pulse width value that has been set is the smallest value among the pulses of the PWM wave (in this example, r20J of pulse P1), and if the answer is NO. , the comparator 23a outputs a pulse having the new predetermined pulse width value, and if Yes, it is determined whether or not the pulse unnecessary period T2 has elapsed.

The determination as to whether or not the pulse unnecessary period T2 is reached is also based on the number of pulse periods t. That is, in this example, PW
There are n pulse periods t during the half cycle of the M wave (during the pulse required period T1), and the ROM 8 causes a counter (not shown) to count the number of pulse periods t, and when the count value reaches n, the pulse period is determined. It is recognized that T has passed and the pulse unnecessary period T2 has entered.

Therefore, as described above, the new predetermined pulse width value is "minimum value J
'(Yes), and the timing at that time is not the pulse unnecessary period T2, that is, if it is NO, it is determined that the half cycle of the PWM wave has ended, and the pulse unnecessary period T2
'f setting is constant, and the above timing is pulse unnecessary period T
If it is 2, that is, if it is Yes, it is determined that the pulse required period T1 of the next half cycle of the PWM wave has arrived, and the output of the PWM wave is executed again.

As described above, the PW of one phase (phase a in the above example)
M wave is output, but other phases b + c + d are also output P
A WM wave is obtained and the pulse motor 2 is rotated smoothly and continuously.

However, the timings at which the PWM waves are outputted are sequentially shifted from each other at 90° intervals between phases a to 6, and these are precisely controlled according to the program in the ROM 8.

The present invention provides an appropriate position i for each phase of the pulse motor, such as a diagonal top.
f to supply a PWM wave, a sinusoidal excitation current flows through the excitation winding of the pulse motor, and therefore the pulse motor has the advantage of being able to rotate extremely smoothly and continuously. This is a great invention.

[Brief explanation of the drawing]

FIG. 1 is an electrical wiring diagram showing an embodiment of a driving device that fully embodies the pulse motor driving method according to the present invention, and FIG. 2 (
A) to) are waveform diagrams showing the relationship between the PWM wave output from the high-frequency wave generating circuit and the excitation current flowing to the excitation winding heel of the pulse motor. A waveform diagram showing the relationship between the excitation currents flowing in each phase a to d, FIG. 4 is an explanatory diagram of PWM waves, and FIG. 5 is an explanation of the operation when the high-frequency pulse generation circuit of the present invention outputs PWMe. FIG. 2: Pulse motor. Agent Patent Attorney Aihiko Fukushi

Claims (1)

[Claims] 1. Apply PW to each excitation winding of the pulse motor with an appropriate phase deviation.
A method for driving a pulse motor, characterized by supplying M waves.