JP2000278979A - Sr motor controlling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate the rotation of a rotor smoothly and speedily by changing over a voltage control in accordance with current conditions during the period when the number of revolutions of the rotor changes sharply from a start. SOLUTION: The rotation of a rotor is induced by impressing excited voltages of the phases corresponding to a sensor 32u which detects a position signal at the time of a startup (t=0) until the sensor detects a first fall (t=t1). In the first cycle after the startup, the excited voltages of the corresponding phases are impressed (t=t3) or interrupted (t=t4) in synchronism with a position signal detected by each sensor. From the second cycle, the voltages are impressed (t=t5, t8) or interrupted (t=t6, t9) after a lapse of a preset delay time from the detection of the position signal by each sensor (t=t4, t7). Then, the delay time is changed over to the value calculated in accordance with the actual number of revolutions of the rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an SR motor used as a motor for generating a steering assist force of a power steering device for a motor vehicle, and more particularly, to a control device in which a rotation speed of a rotor is rapidly increased from a start. It relates to voltage control in a fluctuating time zone.

[0002]

2. Description of the Related Art Use of an SR motor as a motor for generating a steering assist force of a power steering apparatus for an automobile has been studied. Some SR motor control devices apply and cut off an excitation voltage after a predetermined time corresponding to the number of rotations has been detected after detecting the rotation position of the rotor.

[0003]

However, in such a control device, the generated voltage waveform is not suitable for the current situation in a time zone in which the rotation speed fluctuates immediately after the start, and the rotor is not accelerated smoothly. There was a problem.

[0004] Further, since voltage control is not performed until the rotation speed is measured for the first time from the start, a problem has arisen that rotation of the motor is not induced. In view of such a situation, according to the present invention, in the time period described above, the voltage control method is switched according to the current state, thereby smoothly and quickly accelerating the rotation of the rotor, and generating the optimum steering assist force early. It is an object of the present invention to provide a control device for an SR motor which can be operated.

[0005]

According to the first aspect of the present invention, there is provided a rotor provided with projections containing a magnetic material arranged at equal intervals in the circumferential direction and a coil arranged at equal intervals in the circumferential direction. And a control device for an SR motor configured to sequentially apply an excitation voltage to each of the coils so as to apply an excitation voltage of the same phase to one of the coils arranged at a predetermined position. Rotating in synchronization with the rotor, a disk having a slit disposed at a predetermined position corresponding to each of the protrusions, and a position of each slit at a predetermined position corresponding to a coil for applying the excitation voltage of each phase. And a position signal detection sensor to be detected.

Further, as shown in FIG. 1, an actual rotational speed measuring means for measuring the actual rotational speed of the rotor, a first delay time and a second delay longer than the first delay time based on the measured actual rotational speed. Delay time calculating means for calculating time;
Application timing setting means for applying an excitation voltage of a corresponding phase after a lapse of the first delay time from the detection of the position signal by each of the sensors; and an excitation timing setting means for applying the excitation voltage after a lapse of the second delay time from the detection of the position signal. And a cut-off timing setting means for cutting off the voltage. The first and second delay times are set in advance until a predetermined period elapses after each of the sensors detects the position signal including the first rising. A delay time fixing means having a set value is provided.

[0007] That is, in a time zone in which the rotation speed fluctuates rapidly,
Each of the delay times is a set value based on the characteristics of the motor,
In a time period when the rotation speed is stable, these are switched to the calculated values based on the actual rotation speed.

In the invention according to claim 2, the application timing setting means and the cutoff timing setting means further apply and excite the excitation voltage of each phase in synchronization with the rise and fall of the position signal including the first rise. Cut off.

According to the third aspect of the present invention, there is provided starting application means for further applying the excitation voltage of the corresponding phase from the start until the sensor for detecting the position signal at the start detects the first fall.

In the invention according to claim 4, the width of each slit is set so that another sensor detects the rise before one sensor detects the fall. That is, the width of each slit is set to be wider so that the position signals overlap.

[0011]

According to the first aspect of the present invention, reliable voltage control is achieved even in a time period in which the rotational speed fluctuates rapidly in a transient state, the rotor rotation is smoothly and rapidly accelerated, and the optimum steering is quickly performed. An assist force can be generated, and the effect of reducing power consumption can be obtained.

According to the second aspect of the present invention, the driving force according to the present condition is generated even in a time zone in which application and cutoff of the excitation voltage cannot be controlled by the delay time after the detection of the position signal. The rotation of the rotor can be reliably accelerated.

According to the third aspect of the present invention, the excitation voltage can be applied to the coil near the protrusion from the start until the sensor detecting the position signal at the start detects the first fall. It is possible to guide the rotation of the stopped rotor without any additional means.

According to the fourth aspect of the present invention, since the position signals always overlap, it is possible to avoid a state in which none of the sensors detects the position signal due to slit machining tolerance, and to reliably determine the coil to be applied at the time of starting. Can be determined.

Further, since the processing accuracy of the slit can be reduced, the effect of reducing the processing cost can be obtained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic structure of an SR motor and a control device therefor according to an embodiment of the present invention will be described.

FIG. 2 is a system schematic diagram of the control device for the SR motor. In the present embodiment, an example in which a three-phase excitation voltage is applied to the SR motor (ie, a three-phase SR motor) will be described. However, a four-phase or other SR motor is used. Obviously, the present invention can be configured.

The SR motor 1 drives the pump 2 to pressurize a cylinder (not shown) to generate a steering assist force. FIG. 3 shows the internal structure of the SR motor 1.

The SR motor 1 includes a rotor 11 and a stator 12. The rotor 11 has four protrusions 13 arranged at equal intervals on the outer periphery thereof.
Are six coils 14 arranged at equal intervals on the inner circumference thereof.
u, 14v and 14w.

The rotor is rotated by utilizing an electromagnetic force generated by sequentially applying an excitation voltage called a U-phase voltage, a V-phase voltage, and a W-phase voltage to each of the coils 14u to 14w.

The U-phase coils 14u, 14u, 14w
These are referred to as a phase coil 14v and a W-phase coil 14w. The control device of the SR motor 1 includes a control device main body 3 and a control unit 4 connected thereto.

FIG. 4 shows the internal structure of the control device main body 3. The right side of the figure is a front view, and the left side is a side view. The control device body 3 includes a disk 31 and three position signal detection sensors 3.
2 (only one is shown in the side view for convenience).

The disk 31 is connected to the rotor 11 and rotates in synchronism therewith. In addition, the disk 31 includes:
As shown in the drawing, a slit 33 is provided at a predetermined position corresponding to each of the projections 13 at every 90 degrees.
3 is set to a width such that the position signals detected by the sensor 32 overlap (an extreme example is shown in the figure).

On the other hand, as will be described later, sensors 32 are provided at three locations corresponding to the coils 14u to 14w.
The light projecting portions 32a
And a light receiving unit 32b.

As described above, the width of each slit 33 is not set, but the center angle is set to 30 degrees (so that the position signals do not overlap), and the light receiving area of the light receiving section 32b is enlarged. Even so, the position signals can be overlapped, and the same effect can be obtained.

The control unit 4 includes the sensors 32
The rotational position of the rotor 11, that is, the positional relationship between each projection 13 and each of the coils 14 u to 14 w is determined based on the position signal detected by the above, and the excitation voltage of each phase is applied at an optimal timing according to the current state And control to shut off is performed.

The operating principle of the present SR motor will be described with reference to FIGS. In FIG. 5, the rotor 11, the stator 12, the disk 31, and the position signal detection sensor 32, which are the components of the SR motor, are displayed in an overlapping manner.

In FIG. 5, (a) shows the positional relationship between the components at the time ta, and (b) shows the positional relationship at the subsequent time t.
The same positional relationship in b is shown. FIG. 6 shows waveforms of the position signal detected during this time period and the excitation voltage applied to each of the coils 14u to 14w.

In this embodiment, the slits 33 are arranged such that one side end overlaps a straight line connecting the projections 13 as shown in the figure. Each sensor 32 is disposed at a position passing over the center of the slit 33 on a straight line connecting the coils 14u to 14w as indicated by points in the drawing.

Hereinafter, of the sensors 32, those positioned on a straight line connecting the U-phase coil 14u are referred to as U-phase sensors 32.
u and V are located on a straight line connecting the V-phase coil 14v.
The phase sensor 32v and the one located on the straight line connecting the W-phase coil 14w are called a W-phase sensor 32w.

At time ta, the projection 13 is located at a position facing the U-phase coil 14u. Referring to FIG.
The position signal detected by the U-phase sensor 32u falls, and this overlaps with the position signal detected by the V-phase sensor 32v.

At this time, if only the V-phase voltage is applied, an electromagnetic force is generated in the V-phase coil 14v, and the nearby protrusion 13 is attracted, so that the rotor 11 rotates in the direction indicated by the arrow in the figure.

When the rotor 11 rotates 30 degrees from the state shown in (a), the state shown in (b) is reached (time tb), and the projection 13 faces the V-phase coil 14v. Further, the position signal detected by the V-phase sensor 32v falls and overlaps with the position signal detected by the W-phase sensor 32w.

Here, the V-phase voltage is cut off,
When a phase voltage is applied, the rotor 11 is moved to 3
It rotates by 0 degrees, and the protrusion 13 faces the W-phase coil 14w (time tc).

Further, by repeating the same procedure, the rotor 1
1 further rotates 30 degrees and returns to the same state as (a). Thus, after one sensor detects the fall,
Assuming that one cycle is a period until the sensor detects the next fall, the other sensors also detect the fall one by one during this period.

Therefore, the excitation voltage can be sequentially applied to each coil based on the fall detected by each sensor. The starting principle of the present SR motor will be described.

FIG. 7 shows each of the sensors 32 immediately after start-up.
The output signal by u ~ 32w and the voltage waveform generated at this time are shown. FIG. 8 shows the positional relationship between the sensor and the slit at each time.

In order to induce the rotation of the stopped rotor, an excitation voltage of a phase corresponding to a sensor for detecting a position signal is applied at the time of starting (t = 0). That is, as shown in FIG. 8A, when the U-phase sensor 32u detects the position signal, it detects the first fall from the start (t).
= T1), the U-phase voltage is applied.

V-phase sensor 32v or W-phase sensor 32
If w detects a position signal at startup, V-phase and W
A phase voltage is similarly applied. If the position signals overlap at the time of starting, the excitation voltage to be applied is determined based on the rotation direction.

That is, the U-phase sensor 32u and the V-phase sensor 32
If the position signals detected by v overlap (a state corresponding to immediately before time t1), a V-phase voltage is applied, and the position signals detected by V-phase sensor 32v and W-phase sensor 32w overlap. When wrapping, a W-phase voltage is applied.

Next, after each of the sensors 32u to 32w detects the rise of the first position signal, the excitation voltage of the corresponding phase is applied until the fall of the same position signal is detected. For example, the U-phase voltage is applied simultaneously with the detection of the first rise (t = t3) by the U-phase sensor 32u, and cut off simultaneously with the detection of the fall (t = t4).

By such control synchronized with the position signal, a suitable driving force can be generated even in a time zone in which control using the delay time cannot be performed. It should be noted that the control here can also be achieved by focusing only on the fall of the position signal. That is, the excitation voltage to be applied is switched by detecting the fall. For example, V-phase sensor 32v
, The V-phase voltage is cut off, and the W-phase voltage is applied.

Further, after that, until the fluctuation of the rotation speed becomes stable, after the detection of the position signals by the sensors 32u to 32w, the excitation voltage of each phase is passed after a predetermined time set in advance according to the characteristics of the motor. And shut off.

In this embodiment, attention is paid to the fall of the position signal as a reference for calculating the elapsed time.
For example, the timing at which the U-phase voltage is applied is set after the elapse of the first delay time (t = t5, t8) from the detection of the fall (t = t4, t7) by the U-phase sensor 32u, and the timing at which the U-phase sensor is shut off. Is set after the lapse of the second delay time (t = t6, t9).

The first and second delay times are stored in a storage device inside the control unit 4,
After starting, it is updated according to the elapsed cycle. Thereafter, in a time period in which the rotation speed fluctuation is stable, the first and second delay times are switched to the calculated values.

At this time, each of the delay times is determined by the rotor 1
It is calculated for each cycle according to one actual rotation speed (actual rotation speed). In the present embodiment, switching from the set value to the calculated value is determined based on a cycle that has elapsed after the start.

With the above control, the present SR motor is started from a stopped state, and shifts to a working state in which an optimum steering assist force can be generated. FIGS. 9 to 13 are flowcharts showing the control executed by the control unit 4 in the present embodiment.

From the above description, it is clear that the excitation voltage of each phase is similarly controlled each time the rotor 11 rotates by 30 degrees, so here, only the control of the U-phase voltage will be considered.

When the motor is started, the control unit 4 generates a start command (sets a start request flag).
Then, in S1, the output signal from the U-phase sensor 32u is read. In S2, it is determined whether a start request flag is on.

If the user is not standing, the process proceeds to S7. On the other hand, when standing (t = 0), the process proceeds to S3, and it is determined whether or not the U-phase sensor 32u detects a position signal.

If not detected, the process proceeds to S5, while if detected, the control shown in FIG. 11 is executed in S4. S2
At 1, it is determined whether a U-phase voltage should be applied.

Judging from the rotation direction as described above, the U-phase voltage is applied by the U-phase sensor or the U-phase and W-phase sensors.
Since the phase sensor detects the position signal, it is confirmed that the V-phase sensor 32v does not detect the position signal.
It is determined whether a phase voltage should be applied.

When the V-phase sensor 32v detects the position signal, the process proceeds to S5. On the other hand, when the V-phase sensor 32v does not detect the position signal, the U-phase voltage is applied in S22 to induce the rotation of the rotor 11. S23
Then, it is determined whether or not the U-phase sensor 32u has detected the first fall.

If not detected, the same determination is repeated. If detected (t = t1), the U-phase voltage is cut off at S24, and the routine proceeds to S5. Steps S22 to S24 correspond to the activation application unit.

In S5, the cycle count value n is set to 1. In S6, the start request flag is lowered. In S7, it is determined whether or not the cycle count value n is 1.

If the cycle count value n is 1, S8
Then, the control shown in FIG. 12 is executed. In S31, it is determined whether or not the first rising of the position signal after the start is detected.

If not detected, the same determination is repeated. If detected (t = t3), a U-phase voltage is applied in S32. In S33, it is determined whether or not the fall of the position signal has been detected.

If not detected, the same determination is repeated. If detected (t = t4), the U-phase voltage is cut off in S34, and the flow advances to S9. In S9, the cycle count value n is set to 2
And the process proceeds to S11.

On the other hand, if the cycle count value n is 2 or more in S7, it is determined in S10 whether a fall of the position signal has been detected. If not detected, the same determination is repeated. If detected (t = t7), the process proceeds to S11.

At S11, the falling detection at S33 or S10 (t = t4 or t
7) Start counting the elapsed time. In S12, it is determined whether the cycle count value n is 5 or less.

If it is less than 5, it is determined that the time period of the rapid change in the rotational speed is determined, and the process proceeds to S13, where the first delay time t is set.
1 from the table in the storage device, and
Then, the second delay time t2 is similarly searched.

Steps S13 and S14 correspond to delay time fixing means. On the other hand, if the cycle count value n is 6 or more, it is determined that the rotation speed fluctuation is stable,
Measure the actual number of revolutions.

Step S15 corresponds to the actual rotation speed measuring means.
In S16, the first delay time t1 is calculated based on the measured actual rotation speed, and in S17, the second delay time t2 is similarly calculated.

Steps S16 and S17 correspond to delay time calculating means. In S18, if the U-phase voltage is applied at the time of detecting the falling edge (t = t4 or t7), this is forcibly shut off.

In S19, the control shown in FIG. 13 is executed. In S41, it is determined whether or not the value counted by the timer has reached the first delay time t1.

If not reached, the same judgment is repeated.
If it has reached (t = t5 or t8), a U-phase voltage is applied in S42. S41 and S42 correspond to the application timing setting means.

In S43, it is determined whether or not the time value has reached the second delay time t2. If not reached, the same determination is repeated. If reached (t = t6 or t9), the U-phase voltage is cut off in S44.

Steps S43 and S44 correspond to cutoff timing setting means. In S20, the cycle count value is updated to a value obtained by adding 1, and the process returns.
Read the output signal of u.

In this embodiment, the first and second delay times are set or calculated as the elapsed time after the detection of the fall of the position signal. However, the first and second delay times are set or calculated as the elapsed time after the detection of the rise of the position signal. Accordingly, the same effect can be obtained even when the timer starts counting the elapsed time when the rise is detected.

As described above, by switching the voltage control method according to the current state from the start to the time when the rotation speed fluctuation is stabilized, the rotor is smoothly and rapidly accelerated,
The optimum steering assist force can be generated at an early stage, and the power consumption can be reduced.

In the above description, an example in which the motor is used as a motor for generating a steering assist force of a power steering apparatus for an automobile has been described.
Obviously, there are various applications as a device for controlling the R motor.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of the present invention.

FIG. 2 is a system schematic diagram of an SR motor control device according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing an internal structure of the SR motor according to the first embodiment;

FIG. 4 is a schematic diagram showing an internal structure of a control device main body of the SR motor.

FIG. 5 is a diagram showing an operating principle of the SR motor according to the first embodiment;

FIG. 6 shows a sensor output signal and a voltage waveform in the time period of FIG. 5;

FIG. 7 is a voltage waveform controlled by the SR motor control device according to one embodiment of the present invention.

FIG. 8 is a diagram showing a positional relationship between a sensor and a slit in a time zone of FIG. 7;

FIG. 9 is a flowchart (A) showing a processing routine of a sensor output signal.

FIG. 10 is a flowchart (B) showing a processing routine of a sensor output signal.

FIG. 11 is a flowchart showing voltage control for starting.

FIG. 12 is a flowchart showing voltage control synchronized with a position signal;

FIG. 13 is a flowchart showing voltage control by a delay time.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 SR motor main body 2 Pump 3 Control device main body 4 Control unit 11 Rotor 12 Stator 13 Projection 14 Coil 31 Disk 32 Position signal detection sensor 33 Slit

Claims (4)

[Claims] A rotor provided with projections including a magnetic material arranged at equal intervals in a circumferential direction; and a stator provided with coils arranged at equal intervals in a circumferential direction. A control device for an SR motor that sequentially applies an excitation voltage to each of the coils so as to apply an excitation voltage of the same phase to one disposed at a predetermined position, wherein the control device rotates in synchronization with the rotor and corresponds to each of the protrusions. A disk having slits arranged at predetermined positions, and a position signal detection sensor for detecting the position of each slit at a predetermined position corresponding to each coil, while measuring the actual number of rotations of the rotor. Actual rotation speed measurement means; delay time calculation means for calculating a first delay time and a second delay time longer than this based on the measured actual rotation speed; Application timing setting means for applying an excitation voltage of a corresponding phase after a lapse of the first delay time from detection of a signal; and interruption of the excitation voltage after an elapse of the second delay time from the detection of the position signal A timing setting means, and a delay time in which the first and second delay times are set to a predetermined value until a predetermined period elapses after each of the sensors detects a position signal including a first rise. A control device for an SR motor, comprising: fixing means. 2. The method according to claim 1, wherein the application timing setting means and the cutoff timing setting means further apply and cut off the excitation voltage of each phase in synchronization with the rise and fall of the position signal including the first rise. The control device for an SR motor according to claim 1. 3. A start-up applying means for further applying an exciting voltage of a corresponding phase from a start until a sensor for detecting a position signal at the start detects a first fall. The control device of the SR motor according to the above. 4. The SR motor according to claim 3, wherein the width of each slit is set such that another sensor detects a rise before one sensor detects a fall. Control device.