JP2844602B2 - Drive device for torque motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a driving device for a torque motor.

2. Description of the Related Art Conventionally, in a control system using a torque motor, a device that drives the torque motor by applying either positive or negative voltage to the torque motor according to a desired torque direction has been used. Generally, when a positive torque is required, a positive voltage is set, and when a negative torque is required, a reverse negative voltage is set corresponding to a desired torque amount and applied to the torque motor. .

However, such a driving device is a torque motor 1
Inevitably, hysteresis occurs in the input-output characteristics due to the electro-magnetic characteristics described above, which causes an error in the control operation.

In the prior art, a method has been proposed in which the input voltage v shown in FIG. 4 is constantly applied to the input terminal of the drive circuit of the torque motor in order to cancel the above-mentioned effect of the hysteresis.
In FIG. 4, the input voltage v is, for example, several tens Hz to several kHz.
And the application times w1 and w2 in the positive and negative directions are varied according to the required torque. For example, when a positive direction torque is required, the positive direction voltage application time w1 is increased according to the required torque, and when a negative direction torque is required, the negative direction voltage application time w is reduced to 2 as the torque. Increase accordingly. That is, a method of increasing the voltage application rate A in a direction corresponding to a required direction in one cycle T1 of the input voltage v,
The positive input voltage application rate A1 is A1 = (W1 / T1) x 100 (%) ... (1) The negative input voltage application rate A2 is A2 = (W2 / T1) x 100 (%) ... (2) ). However, A1 + A2 = 100 (%). Accordingly, when the required torque is zero, the application rates A1 and A2 of the input voltages applied in both the positive and negative directions are equally 50%. When a torque is required in any direction, the voltage application rate corresponding to the direction is increased, and the voltage application rate in the opposite direction is reduced. When the maximum torque is required, the voltage application rate A corresponding to the direction is set to 100%.

The driving of the torque motor is performed by a driving circuit 1 shown in FIG.
Done in In FIG. 5, four transistors Q1 to Q1
Q4 is bridge-connected and functions as a switching element. In a period w1 in which the input voltage v1 is applied to the input terminal a side to which the bases of the transistors Q1 and Q4 are commonly connected, the transistors Q1 and 14 are turned on, the transistors Q2 and Q3 are turned off, and the current I1 is Vm flows in the direction indicated by the solid line, and the torque motor 2 generates a forward torque.
During a period w2 in which the input voltage v2 is applied to the input terminal b to which the bases of the transistors Q2 and Q3 are commonly connected, the transistors Q2 and Q3 conduct and the current flows in the torque motor 2 in the direction indicated by the broken line. I2 flows, and the torque motor 2 generates a negative torque. Accordingly, the alternating waveform shown in FIG. 4 is applied to the input terminals a and b, and the voltage application rate A
By setting 1, A2, a desired torque can be generated from the torque motor 2.

In this way, by alternately applying a voltage to the torque motor, and in particular, when the torque is zero, by applying a voltage of equal magnitude to the torque motor, the input torque command value and the output torque are linearly adjusted. Correspondingly, input / output characteristics from which hysteresis has been removed can be obtained.

However, although the above-described torque motor driving device according to the prior art is effective in removing hysteresis, the input voltage is constantly applied to the torque motor driving circuit 1 so that the torque Is zero, the current i as shown by the broken line in FIG. Accordingly, Joule heat is always generated from the torque motor 2 and causes not only a rise in temperature but also an increase in power consumption.

In order to solve the above-mentioned problem, a method of generating a pulse signal having a waveform as shown in FIG. 6 and controlling a drive circuit of a torque motor based on the waveform has been proposed as a second prior art. (For example, Japanese Patent Application No. 61-2322
94).

In the positive period w1 of the waveform shown in FIG. 6, the torque motor is energized in the positive direction, and in the negative period w2, the torque motor is energized in the negative direction. The ratio of each of the periods w1 and w2 included in one cycle T2 is represented by the voltage application rates A1 and A2 in the same manner as in the prior art described above, and the voltage application rates are determined according to the torque required for the torque motor. A, that is, the positive direction voltage application period w1 or the negative direction voltage application period w2 is varied. When the required torque is small or zero, a no-voltage period w3 is provided in one cycle T2.

When the torque required for the torque motor is zero, the positive voltage application rate A1 and the negative voltage application rate A2 are equal, for example, 10%, respectively, and the remaining no-voltage period w3 is 80%. As described above, the no-voltage period w3 is provided, and when the torque is zero, the value of the current flowing through the torque motor is suppressed. Therefore, the power consumption during the no-voltage period w3, and therefore, the heat generation when the torque is zero. Can be suppressed.

However, the input / output characteristics of the torque motor obtained by the method according to the second prior art are, as shown in FIG. 7, the torque output value τ when the torque command value j is near zero.
Becomes non-linear, resulting in more errors than in the first prior art scheme. This is because the pulse signal has a positive / negative symmetrical waveform as shown in FIG. 6, but the current i2 flowing through the torque motor has a phase lag correspondingly, and the current waveform has a positive / negative asymmetrical shape.

Although the above-described first or second prior art torque motor driving devices have been proposed to eliminate the effect of hysteresis, on the one hand, power consumption, ie, heat generation, is a problem, and on the other hand, the linearity, ie, error, of the torque is problematic. Is a problem. Accordingly, there has been a demand for a torque motor drive device that suppresses the amount of heat generated when the torque is zero and that does not impair the linearity of characteristics.

An object of the present invention is to solve the above-mentioned technical problems, and when the torque required for a torque motor is small,
An object of the present invention is to provide a torque motor drive device that suppresses the amount of heat generated by current and does not impair the linearity of torque characteristics.

Means for Solving the Problems The present invention provides: (a) a torque motor 12 that generates a positive direction torque and a negative direction torque respectively corresponding to each direction of the current of one terminal and the other terminal; (C) a first switching transistor Q11 connected between the one terminal of the torque motor 12 and the one output terminal of the DC power supply, and (d) a torque motor. A second switching transistor Q12 connected between the other terminal of the DC power supply 12 and the one output terminal of the DC power supply; and (e) between the one terminal of the torque motor 12 and the other output terminal of the DC power supply. A third switching transistor Q13 having a control terminal connected to the control terminal of the second switching transistor Q12, and (f) the other terminal of the torque motor 12 and the other output of the DC power supply. A fourth switching transistor Q14 having a control terminal connected to the control terminal of the first switching transistor Q11 and a control terminal of the first switching transistor Q11; and (g) torque command value generating means for generating positive and negative torque command values. (H) data processing means 13a for generating a voltage application rate B (%) corresponding to positive and negative torque command values in response to the output of the torque command value generating means; and (i) when the torque command value is zero. AO (%) when the voltage application rate is predetermined, and the voltage application rate B from the data processing means
(%) In response to voltage application rate Ap (%) in the positive direction
And the voltage application rate Am (%) in the negative direction are as follows: (I) In the case of positive torque (1) When 0 ≦ B ≦ (100−2 · AO), Ap = B + AO Am = AO (2) When B> (100−2 · AO), Ap = (100−AO) + {B− (100−2 · AO)} / 2 Am = 100−Ap (II) In the case of negative torque (3) − When (100-2 · AO) ≦ B ≦ 0, Ap = AO Am = −B + AO (4) When B <− (100−2 · AO), Ap = AO − ｛− B− (100−2 · AO)｝ / 2 Am = 100−Ap Voltage application rate setting means 13b calculated by: (j) a first positive pulse width tp and a first first pulse width tp with respect to the current at the other output terminal of the DC power supply. The no-voltage period tz1, the negative second pulse width tm, and the second equal to the first no-voltage period tz1
The period T constituted in this order by the no-voltage period tz2
Pulse signal generating means 13c for applying a drive pulse having 12 between the control terminals of the first and fourth switching transistors Q11 and Q14 and the control terminals of the second and third switching transistors Q12 and Q13. A first positive pulse width tp is determined corresponding to the voltage application rate Ap, a second negative pulse width tm is determined corresponding to the voltage application rate Am, a first non-voltage period tz1, Two non-voltage periods tz2 each include pulse signal generating means 13c defined as {100- (Ap + Am)} / 2.

According to the present invention, one output terminal + Vm of the DC power supply is connected to the first output terminal.
The other output terminal is connected to the third and fourth switching transistors Q13 and Q14 at the ground potential in the embodiment described later, and the pulse signal generating means 13c is connected to the second and third switching transistors Q11 and Q12. A drive pulse having a period T12 is generated with reference to a ground potential in the later-described embodiment, which is a potential of the other output terminal of the DC power supply, to control a control terminal of the first and second switching transistors Q11 and Q14. And to a base which is a control terminal of the second and third switching transistors Q12 and Q13, a positive / negative torque command value is generated from a torque command value generating means, and the data processing means 13a outputs a positive / negative torque A voltage application rate B (%) corresponding to the command value is generated, and when the torque command value is zero, the voltage application rate setting means 13b determines the voltage application rates Ap and Am in the positive and negative directions. Ap, Am in response to the voltage application rate B (%) are values calculated by the above (1), (2), (3) and (4), and the pulse signal The generating means 13c determines the widths tp, tm of the positive and negative first and second pulses corresponding to the positive and negative voltage application rates Ap, Am, and a first non-voltage period between tp and tm. tz1 and a second no-voltage period tz2 between tm and tp equal to the first no-voltage period tz1 are {100− (Ap
+ Am)｝ / 2, whereby the current flowing through the torque motor is reduced to suppress heat generation and to achieve a good linearity of the input / output characteristics of the torque motor.

Embodiment FIG. 1 is a block diagram showing an electric configuration of a torque motor driving device according to an embodiment of the present invention. The torque motor drive device 11 includes pulse generating means 13 for generating a desired torque to the torque motor 12, and a torque motor drive circuit (hereinafter abbreviated as drive circuit) 14.

Data relating to the torque command value is input to the pulse generating means 13 via a line 110. Data processing unit 13a
Converts the data into data necessary for realizing the operation of the drive circuit 14, and inputs the data to the calculation unit 13b. Arithmetic unit 13b
Calculates the positive voltage application rate Ap and the negative voltage application rate Am necessary to generate a desired torque from the data, and the pulse signal generation unit 13c calculates the voltage application rate Ap given from the calculation unit 13b. , Am, and a pulse signal P having a waveform corresponding to Am is generated and applied to the drive circuit 14 via lines l11 and l12.

FIG. 2 is a waveform diagram of a pulse signal P for controlling the torque motor drive circuit 14 of the present embodiment. Referring also to FIG. 1, the pulse signal P is generated by the pulse signal generation circuit 13c, and in one cycle of one cycle T12, a positive pulse p1 having a pulse width tp and a negative pulse p1 having a pulse width tm are generated. When the required torque is small or the torque is zero with a pulse alternating waveform with the direction pulse p2, a pulse pause period between the positive direction pulse p1 and the negative direction pulse p2, that is, a no-voltage period tz1, The feature is that tz2 was interposed.
In particular, when the torque is zero, tp = tm, tz1 = tz2, and the positive voltage application rate Ap and the negative voltage application rate Am are equal.
For example, it is set to 10%, and the deduction of 80% is the no-voltage period tz
It is set to be the sum of 1, tz2.

When a positive torque is required, the positive voltage application time tp is increased, that is, the positive voltage application rate Ap is increased, and the negative voltage application time tm is reduced, that is, the negative voltage application rate Am is reduced. And When a negative torque is required, the negative voltage application time tm is increased, that is, the negative voltage application rate Am is increased, and the positive voltage application time tp is reduced, that is, the positive voltage application rate Ap is increased. Small.

Assuming that the required torque changes from zero to a maximum of 100, the voltage application rate when the torque is zero is A0%, and the application rate corresponding to the torque command value is B%, the positive and negative voltages in one cycle T12 The application rates Ap and Am are set as follows according to the direction of the required torque and the value of the command value B.

 For forward torque: (a) When 0 ≦ B ≦ (100−2 · A0) Apa = B + A0 Am = A0 (3) (b) When B> (100−2 · A0), Apb = (100−A0) + {B− (100−2 · A0)} / 2 Amb = 100−Apb (4) In the case of negative torque: (c) − (100−2 · A0) ≦ B ≦ When 0, Apc = A0 Amc = −B + A0 (5) (d) When B <− (100−2 · A0), Apd = A0 − {− B− (100−2 · A0)} / 2 Amd = 100−Apd (6) All units are%.

For example, if the voltage application rate A0 is set to 10% in advance, when the required torque is zero, that is, when B = 0, the positive voltage application rate Ap and the negative voltage application rate Am are expressed by the above equation (3). As a result, Ap = Am = 10 (%), and the non-voltage periods tz1 and tz2 become 1/2 of the remaining 80%.

B = 30 (%), that is, the positive voltage application rate Ap and the negative voltage application rate Am when a positive torque of 30% of the maximum torque is required, are obtained by Ap = 40 ( %), Am
= 10 (%), the remaining 50% is the non-voltage period tz1, tz2
And these are 25% each.

Also, when B = 100−2 × A0 = 80 (%), that is, when a forward torque of 80% of the maximum torque is required, Ap = 90 (%), Am = 10 by equation (3) as above. (%), So that the non-voltage periods tz1 and tz2 are both 0.
That is, when B is less than 80 (%), a non-voltage period having the same length intervenes between the positive pulse voltage and the negative pulse voltage, and when B is 80 (%) or more, the non-voltage period does not intervene.

The required torque is larger, for example, B = 90
(%), Ap = 95 (%), A
m = 5 (%). At this time, the no-voltage period is naturally zero. The same applies to the case where a negative torque is required.

With reference to FIG. 1, the voltage application rate when the torque is zero is previously set to, for example, 10%, and a command value B corresponding to a desired torque is input to pulse generating means 13. Thus, the voltage application rates Ap and Am are calculated, and the pulse signal P required for driving the torque motor is derived from the pulse signal generation circuit 13c to the drive circuit 14.

The drive circuit 14 includes four switching transistors Q1
1 to Q14 are bridge-connected, and one terminal of the torque motor 12 is connected to the emitter of the transistor Q11 and the transistor Q11.
At the connection point of the 13 collectors, the other terminal is the transistor Q1
At the connection point of the emitter of 2 and the collector of transistor Q14,
Each is connected. Drive power supply Vm for torque motor 12
Has its + potential connected to the junction of the collectors of the transistors Q11 and Q12,
It is connected to the connection point of each emitter of Q13 and Q14.

Now, when the pulse signal P shown in FIG. 2 is applied,
By the positive pulse p1, the transistors Q11 and Q14 are turned on, and the transistors Q12 and Q13 are turned off. Accordingly, from the power supply Vm, the current I11 flows in the direction indicated by the solid arrow, ie, the transistor Q11 → the torque motor 12 → the transistor Q14.
, And the torque motor 12 generates a positive torque. Also, the transistor Q1 is generated by the negative pulse p2.
2, Q13 conducts, and transistors Q11, Q14 are cut off. Accordingly, a current I12 in the opposite direction to that described above flows from the power supply Vm in the direction indicated by the dashed arrow, and the torque motor 12 generates a negative torque. The driving of the torque motor 12 is performed in this manner, and the generated torque is determined by the time width in which the transistors Q11 to Q14 are turned off. That is, the positive / negative voltage application rate A
The generated torque of the torque motor 12 can be set by p and Am.

In particular, when the required torque is zero, the pulse width tp of the pulse signal P shown in FIG. 2 is tp = tm (in this embodiment, for example, 10%), and the non-voltage period tz1 = tz2
(In this embodiment, each is set to, for example, 40%), and the current i12 flowing through the torque motor 12 is a broken line in FIG. The input / output characteristic is excellent in linearity as shown in FIG. 3, which eliminates the nonlinearity caused by the asymmetry of the current waveform as described in the section of the prior art. And 80 in the above example.
% Of power consumption is realized, and heat generation when the torque is zero or when the required torque is small is remarkably suppressed.

Effects of the Invention According to the present invention, positive and negative drive pulses are alternately applied to a torque motor in one cycle T12, a voltage application rate corresponding to a torque command value is determined, and a torque corresponding to the torque command value is changed in a positive direction or a negative direction. Generate in the direction.

In particular, according to the present invention, when the torque command value is zero,
The voltage application rate Ap, Am in each of the positive and negative directions is set to a predetermined value A0, and between Ap and Am, expressed by {100- (Ap + Am)} / 2, and a non-voltage period of equal length is provided. This not only suppresses heat generation but also achieves good linearity of the output characteristics of the torque motor.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electric configuration of a torque motor driving device according to one embodiment of the present invention, FIG. 2 is a waveform diagram of a pulse signal obtained by this embodiment, and FIG. 3 is a torque motor according to this embodiment. FIG. 4 is a waveform diagram of a pulse signal according to the prior art, FIG. 5 is an electric circuit diagram of a drive circuit of a torque motor, FIG. 6 is a waveform diagram of a pulse signal according to another prior art, FIG. 7 is a graph showing input / output characteristics of another conventional torque motor. 11 ... Torque motor drive device, 12 ... Torque motor, 13
... Pulse generating means, 13a ... Data processing unit, 13b ... Calculation unit, 13c ... Pulse signal generation circuit, 14 ... Torque motor drive circuit, P ... Pulse signal, Q1 to Q4 ... Transistor

Continuation of the front page (56) References JP-A-57-196873 (JP, A) JP-A-63-87190 (JP, A)

Claims (1)

(57) [Claims] (A) a torque motor (12) that generates positive and negative torques corresponding to the respective directions of currents of one terminal and the other terminal; (b) one output terminal and the other output terminal; (C) a first switching transistor Q11 connected between the one terminal of the torque motor 12 and the one output terminal of the DC power supply; and (d) the other terminal of the torque motor 12. A second switching transistor Q12 connected between the one output terminal of the DC power supply and (e) a second switch connected between the one terminal of the torque motor 12 and the other output terminal of the DC power supply; A third switching transistor Q13 having a control terminal connected to the control terminal of the switching transistor Q12, and (f) connected between the other terminal of the torque motor 12 and the other output terminal of the DC power supply. A fourth switching transistor Q14 having a control terminal connected to the control terminal of the first switching transistor Q11; (g) torque command value generating means for generating positive and negative torque command values; and (h) torque command value generation. A data processing means 13a for generating a voltage application rate B (%) corresponding to a positive or negative torque command value in response to an output of the means; (i) when a voltage application rate when the torque command value is zero is predetermined AO (%), And the voltage application rate B from the data processing means.
(%) In response to voltage application rate Ap (%) in the positive direction
And the voltage application rate Am (%) in the negative direction are as follows: (I) In the case of positive torque (1) When 0 ≦ B ≦ (100−2 · AO), Ap = B + AO Am = AO (2) When B> (100−2 · AO), Ap = (100−AO) + {B− (100−2 · AO)} / 2 Am = 100−Ap (II) In the case of negative torque (3) − When (100-2 · AO) ≦ B ≦ 0, Ap = AO Am = −B + AO (4) When B <− (100−2 · AO), Ap = AO − ｛− B− (100−2 · AO)｝ / 2 Am = 100−Ap Voltage application rate setting means 13b calculated by: (j) a first positive pulse width tp and a first first pulse width tp with respect to the current at the other output terminal of the DC power supply. The no-voltage period tz1, the negative second pulse width tm, and the second equal to the first no-voltage period tz1
The period T constituted in this order by the no-voltage period tz2
Pulse signal generating means 13c for applying a drive pulse having 12 between the control terminals of the first and fourth switching transistors Q11 and Q14 and the control terminals of the second and third switching transistors Q12 and Q13. A first positive pulse width tp is determined corresponding to the voltage application rate Ap, a second negative pulse width tm is determined corresponding to the voltage application rate Am, a first non-voltage period tz1, 2. A driving device for a torque motor, wherein two non-voltage periods tz2 each include pulse signal generating means 13c defined as {100− (Ap + Am)} / 2.