JPS60219989A - Load drive device - Google Patents

Abstract

PURPOSE:To produce the pole position and the speed information of a motor with less number of output lines by outputting different signals in response to the rotation of the motor and the electric angle position of a rotor, and detecting the pole position of the rotor. CONSTITUTION:Pulse signal generating means 12, 14 output different pulse trains in response to the rotation of a motor 1 and the electric angle position of a rotor 2. Pole position detecting means 13 receive the outputs of the means 12, 14 and detects the pole position of the rotor 2. Switching control means 7 controls the output of speed instructing means 8, and output frequency of power control means 3 in response to the outputs of the means 12, 14, and selects switching elements S1-S6 for switching the means 3 with respect to the outputs of the means 12, 14 and the output of the means 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a load driving device that drives a load using an electric motor having magnetic poles in its rotor.

[Background of the invention]

Recently, AC motors have been widely used for speed and position as well as DC motors.

By the way, when controlling a motor having magnetic poles on its rotor, it is necessary to know the rotational speed of the motor and the position of the magnetic poles of the rotor. To find out these things, it is generally desirable to use a digital speed position detector whose output is stable even when the temperature changes, but the one proposed previously was published in Japanese Patent Application Laid-Open No. 58-1555.
As shown in No. 12 and Japanese Unexamined Patent Publication No. 58-37296, a large number of output lines were required. The need for a large number of output lines increases the possibility of disconnection accidents,
This wiring requires a lot of man-hours, and the space required to house the output lines also increases, which is undesirable.

[Purpose of the invention]

The present invention has been made in view of these points, and its purpose is to provide a detector that can extract magnetic pole position and speed information of a motor with fewer output lines than conventional ones. The purpose is to configure a load driving device.

[Summary of the invention]

In the present invention, an electric motor, power control means, pulse signal generation means, magnetic pole position detection means, speed command means, and switching control means are provided. The electric motor drives the cargo,
The rotor has magnetic poles.

This rotor may have permanent magnets or may have crossed magnetic poles. The power control means has a plurality of switching elements and controls the power applied to the electric motor.

The pulse signal generating means outputs different pulse trains in accordance with the rotation of the electric motor and in accordance with the lightning and atmospheric angle of the rotor (1M). The magnetic pole position detection means detects the magnetic pole position of the rotor in response to the output of the pulse signal generation means.

The speed command means outputs a speed command for the electric motor.

The switching control means controls the output frequency of the power control means in accordance with the output of the speed command means and the output of the pulse signal generation means, and controls the output frequency of the power control means in accordance with the output of the pulse signal generation means and the output of the magnetic pole position detection means. Select the switching element for switching.

[Embodiments of the invention]

Hereinafter, a case will be described in which a load (not shown) is driven by an AC motor 1 having a two-pole configuration having six-phase armature windings 1U, 1V, and 1W. The rotor 2 of the AC motor 1 has a pair of magnetic poles N
and S. As shown by 6, the power control means receives electric power from a three-phase AC power source 4, and includes a forward converter 5 for three-phase full-wave rectification, a smoothing capacitor C8, and an inverse converter 6. It is composed.

The inverter 6 has six switching means S, -S0, and although not shown, a feedback diode is connected in antiparallel to each switching means.

The switching control means, generally indicated by 7, includes a speed command means 8 and a shunt resistor 9 for detecting the wake-up motor current of each phase.
, 10.11 and the first pulse signal generator 12
It is configured to receive the output signal of the magnetic pole position detection means 13 and output a signal for controlling the switching elements 81 to S6 of the power control means 3. Magnetic pole position detection means 1
Reference numeral 6 indicates the output of the first pulse signal generating section 12 and a second pulse generating means which together with the first pulse signal generating section 12 constitutes a pulse generating means.
It is configured to detect the magnetic pole position of the rotor 2 in response to the output of the pulse signal generator 14.

The rotor 2 has a code plate P having the pattern shown in FIG.
are directly connected. This code plate PVC is provided with two rows of tracks 1/) and 17 surrounding the center of rotation 15.

The substrate of the code plate P is made of aluminum alloy and has a disk shape. A thin film of magnetic paint is baked onto the tracks 16 and 17 to form a pattern, and the sticky portions are the portions with the thin film.

On the track 16, 100B magnetic coating films are welded at equal intervals.

In addition, each angle range θ obtained by dividing the entire circumference of the track 17 into six equal parts
, -06 include coating films a and 7 provided in the track 16.
Coating films b to g are provided at 9 equal intervals 11C2A. The coating film provided within the angular range θ1 has a width that overlaps with one of the coating films a when viewed in the radial direction from the rotation center 15,
Angle range 0. The coating film C provided inside has a width that overlaps two of the coating films a when viewed in the radial direction from the rotation center 15. Below angle range '$1 #41 03. 018 is on the surface of the code board P. As the number of coatings d, e, f, and g overlaps with coating film a, the number gradually increases to 3, 4, 5, and 6 as the number advances to θ6. This is a pulse generating means mounting plate arranged closely to which a first pulse signal generating section 12 and a second pulse signal generating section 14 are attached. The first pulse generator 12 is composed of magnetoresistive elements 19 to 22 as shown in FIG. 4, and the second pulse signal generator 14 is composed of magnetoresistive elements 26 and 24.

Of these, the magnetic and resistive elements 19, 21 and 23 are arranged to face the track 16 or 17 and to be susceptible to the magnetic influence of the magnetic coating. Encased magnetoresistive element 20.22
and 24 are arranged at locations in each track 16.degree. 17 that are not easily affected by magnetism, and the respective magnetoresistive elements 19-24 can be easily formed on the substrate by photo-etching or sputtering.

With this configuration, for example, the magnetoresistive elements 19 and 2
A constant voltage is applied to the series circuit with magnetoresistive element 20.
By detecting the voltage change at both ends of 0, the passage of the magnetic coating film, that is, the rotational state of the code plate P can be detected.

The reason why two sets of magnetoresistive elements 19, 201, and 21 and 22 are provided in series on the track 16 is to detect the direction of rotation of the rotor 20 by looking at the code plate P. Therefore, the spacing between the magnetoresistive elements 19 and 21 is selected to be one quarter of the coating pitch t provided on the track 16.

Now, for ease of explanation, FIG. 5 shows the voltage changes between the respective terminals of the magnetoresistive elements 2o and 24 when the rotor 2 rotates once at a constant speed.

In other words, the voltage signal A between both terminals of the magnetoresistive element 200 has a pulse shape at constant intervals with respect to time LK. Magnetoresistive element 2
The voltage at both terminals of the 20-volt terminal is in the form of pulses at regular intervals with respect to time t, but the signal width changes every time the rotor 2 rotates 60 degrees in electrical angle.

Although the voltage change between both terminals of the magnetoresistive element 220 is not shown in FIG. 5, it takes the form of a pulse whose phase is shifted by 90 degrees in electrical angle with respect to the voltage A.

Next, the switching control means 7 will be explained.

Two-phase signal A output from the first pulse signal generator 12
and B are input to the quadrupling circuit 512 and processed to have a frequency four times higher, and then converted into an analog value speed feedback signal by the F/V converter 313, and the target operating speed of the motor 1 is set at the matching point 302. The output signal of the speed command means 8 is compared with the output signal of the speed command means 8. The two-phase speed detection signals A and B are
At the same time, it is input to the forward/reverse determining unit 611, and the rotation direction of the lightning and motive 1 is determined. This determination result is input to the up/down selection terminal U/DK of the up/down counter 314, and depending on the determined rotational direction of the electric motor 1, addition or subtraction operation of the up/down counter 514 is selected. Further, the speed detection signal A is inputted to the clock input terminal CjPK of the up/down counter 314.

At this point, explanation of the switching control means 7 will be temporarily discontinued, and the magnetic pole position detection means 13 will be explained.

The inverted output of the signal F and the signal A are subjected to a logical operation in an AND circuit 328, resulting in a signal F1 shown in FIG.

This signal F is input to the clock terminal UO of the counter 629. The counter 629 is the second pulse signal generating means 1
It is reset by inputting the signal F of No. 4 to the clear terminal cLK.

The output F2 of the counter 329 is input to the central processing unit 330. The central processing unit 9330 starts at block B, as shown in FIG. 6, and reads 1 into the final count value of the counter 329 at block B. In block B3, 0 is read as the previous final count value of the counter 329 stored in advance, and in block B4, K is read. Compare with and with. If Kl'' is KO, the process returns to block B2.

For example, K. When moving from =1 to =2, the number is 8.
Preset to 10.

Note that the code 4iP is the interval θ, and 0. The boundary position of 3 degrees with the magnetic pole N of the rotor 2 is connected together.

Now, we will return to the explanation of the switching control means 7 again.

Now, one rotation of electric motor 1 causes speed detection signal A to become 1008.
Since pulses are generated, one pulse input to the down counter 314 during up is indicative of 360°/100B rotation of the motor 1. Therefore, read the value of this up/down counter '514 and add 3 to this count number.
By multiplying 60°/1008, we get 'Motivation 1'
You can know the zero rotation angle. The count value of this up/down counter 614 is used as an address signal for the sine wave tables 515 to 317 at the next stage tL. That is, the ROMVCs constituting the sine wave tables 315 to 317 correspond to the address signal (in other words, 10 rotation angles of the electric motor) and have the values Euv, Kvw, Eiwv Kuv of each sine wave similar to each line voltage waveform required for control. =sin ωt Kw 鴬=81n←t−g However, ω is an angular velocity that is stored in advance. Sine wave table 315-3
The digital signal output by 17 is sent to D/A converter 31
After being converted into an analog phase command signal at 8 to 320,
Output to multipliers 325 to 327 and speed control amplifier 30
The multiplier is combined with the speed control signal of the abutment point 302 input through 3 to become the drive control signal of the inverter 6. The inverter 6 receives these drive command signals and controls the conduction of the switching elements S, ~S, of the inverter 6, and controls the line pressure of each of the three phases supplied to the motor 1. It is something. Note that 305 and 306 are current feedback matching points and current control amplifiers for ensuring operation under appropriate load conditions.

In the above embodiment, in the initial stage of starting the electric motor 1, until the preset terminal PRK reset signal of the up/down counter 314 is input, the address signals output to each of the sine wave tables 315 to 617 are Since the contents are not specified, control operations may become unstable. As a countermeasure to this problem, it is possible to adopt the method shown in the seventh factor.

That is, upon arrival of the signal 350 for starting the electric motor 1, the central processing unit 330 starts as shown in block BIoVC, and at B11 the up/down counter 6 is started.
14 to any desired value. This arbitrary numerical value may be the final value at the time of the previous operation, or may be a fixed value. Thereafter, the process moves to block I3u, and it is determined whether the output of the pulse signal generating means has changed. If it has changed, it moves to block B, 3, blocks B2+ B+++ B4, B6 shown in FIG. 6 are passed to recognize the magnetic pole position, and then moves to block B14, where voltage is applied to a predetermined phase. From then on, normal operation will occur.

If it is determined in block BI2 that there is no change in the output of the pulse signal generating means, block B1. , and a different value is preset to the preset terminal PR of the up/down counter 314.

According to this, the switching control means 17 applies power to an arbitrary phase of the motor at the time of starting, and thereby supplies power to a different phase if the signal from the pulse signal generating means does not change.

8 and 9 show different embodiments of the present invention.

Although not shown in this embodiment, the same number of magnetic coating films are baked onto the portions corresponding to tracks 16 and 17 shown in FIG. 3. On the track 16, 1008 magnetic coatings are printed at equal intervals, just like the one shown in FIG.

In track 17, there is one in each of #1 to θ6, which are divided into six equal parts.
Sixty-eight magnetic coating films are provided, and these coating films are baked so that a phase difference occurs in each section 01 to θ6 with respect to the coating film provided on the track 16.

In this embodiment, the magnetoresistive elements 21 and 22 are not provided, and the direction of rotation is detected by observing the phase difference of the 1st position with respect to the A signal. Therefore, counter 3
As 29, one having a set terminal S and a clear terminal CL is used, and a timer '560 is further provided. counter 32
Input signal A to set terminal 8 of 9, and input signal A to clear terminal C.
LK inputs signal F. Furthermore, the signal of timer '560 is input to the clock terminal.

The central processing unit 330 receives the output of the counter 529 and presets the up/down counter 514 according to the flow shown in FIG.

The central processing unit 630 further monitors the change in the count of the counter 629, determines whether the count is increasing or decreasing, that is, the direction of rotation, and selects the up/down selection terminal U/ of the up/down counter 314. D [,
A signal is sent out according to that tendency.

Similarly to FIG. 5, in FIG. 9, the voltage changes between the respective terminals of the magnetoresistive elements 20 and 24 are shown as A and F when the rotor 2 rotates once at a constant speed.

Further, each section θ, ~θ between KA and F below. The time axis t is extended to show the phase relationship in A/.

It is indicated as F'.

Although the two embodiments have been described above, the present invention is not limited to these embodiments and can be modified in various ways.

For example, in the above embodiment, the case where two tracks were provided on the code plate was explained, but θ1. θ,.

If a magnetic coating film whose width changes for each section shown in .

Further, in the above embodiments, a magnetic coating film was used as the pulse signal generating means, but a photoelectric type may also be used.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, a pulse generating means is provided which outputs different signals according to the rotation of the electric motor and according to the electrical angle #f of the rotor, and the rotation is performed in response to the output of the pulse generating means. Since the magnetic pole position detecting means for detecting the magnetic pole position of the motor is provided, it is possible to construct a load driving means equipped with a detector that can extract the magnetic pole position and speed information of the motor with a small number of output lines.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a block diagram showing an embodiment of the load driving device of the present invention, FIG. 2 is a circuit diagram showing more details of the device shown in FIG. 1, and FIG. 3 is a diagram similar to the one shown in FIG. FIG. 4 is a plan view showing an example of a code plate for a detector used in the embodiment shown in FIG. , FIG. 5 is an output waveform diagram of the pulse signal generating means and other parts shown in FIG. 1, FIGS. 6-9 are flow diagrams showing the operation of the central processing unit shown in FIG. FIG. 8 is a circuit diagram showing a different embodiment of the load driving device of the present invention, and FIG. 9 is an output waveform diagram of the pulse signal generating means of the embodiment shown in FIG.

Claims (1)

[Claims] 1. A motor having magnetic poles in its rotor and driving a load; power control means having a plurality of switching elements and controlling power applied to the motor; pulse signal generating means for outputting different signals in accordance with the rotation of the electric motor and in accordance with the electrical angle position of the rotor; and a magnetic pole position detector for detecting the magnetic pole position of the rotor in response to the output of the pulse signal generating means. a speed command means for outputting a speed command for the AC motor; and a pulse signal generation means for controlling the output frequency of the power control means according to the output of the speed command means and the output of the pulse signal generation means. and switching control means for selecting the switching element to be controlled in relation to the output of the magnetic pole position detection means and the output of the magnetic pole position detection means, wherein the pulse signal generation means controls the rotation of the electric motor. a first pulse signal generating section that outputs a first pulse train in accordance with the rotation of the motor, and a second pulse signal generating section that outputs a second pulse train that varies depending on the rotation of the electric motor and in accordance with the electrical angular position of the rotor. 2. The load according to claim 1, wherein the magnetic pole position detection means is configured to detect the magnetic pole position of the rotor in response to an output from the second pulse signal generator. Drive device. 36 The second pulse signal generator is configured to divide the electrical angle of 360° of the electric motor into a plurality of sections, and output pulses with the same width in the same section and pulses with different widths in different sections. A load driving device according to claim 2, characterized in that: 4. As mentioned above, the output of the first pulse signal generator and the output of the second pulse signal generator are configured to output the same number of pulses per unit rotation of the AC motor, and Claim 2, characterized in that the interval between when the signal generating section issues a pulse and when the second pulse signal generating section issues a pulse is configured to vary depending on the electrical angle of the motor. The load driving device described in Section 1. 5. The switching control means is configured to apply power to any phase of the motor at the time of startup, and to supply power to different phases if the signal from the pulse signal generation means does not change. A load I@ moving device according to any one of claims 2 to 4, characterized in that: 6. Any one of claims 2 to 5, wherein the second pulse signal generating section is configured to generate different pulse trains depending on the rotational direction of the rotor. One load drive.