JPH0334308B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention provides a control device for an electric motor and a control method thereof.

[Background of the invention]

In order to perform faithful operation control with respect to the operation command value, feedback control is performed not only on the operating speed information of the electric motor but also on the rotational position information of the rotor of the electric motor. FIG. 1 shows an example of a control system for a commutatorless motor (hereinafter simply referred to as a motor) developed for this purpose. That is, to briefly explain this, 1, 2, and 3 are a diode bridge circuit of the converter section, a smoothing capacitor, and a power transistor circuit of the inverter section, which constitute an inverter device for driving the motor 13. Motor 13
is composed of a three-phase armature winding 7 that receives power from an inverter device, and a rotor 8 that has polar characteristics. Reference numerals 11 and 14 are a speed generator and a position detector, respectively, connected to the rotor 8 and used to extract operating speed information, and a position detector for extracting rotational position information of the rotor 8. As the position detector 14, one that combines a light plate 9 and a photoelectric sensor 10, or one that uses a magnetic sensor has already been proposed. 12 is a speed generator 11
This is a control device that mainly controls the base signal of the power transistor circuit 3 of the inverter section based on the feedback signal from the position detector 14.
The purpose is to supply current of appropriate proportion and magnitude to. Note that 4, 5, and 6 are resistors for detecting current at various locations.

In such a system, the initial setting of the position detection means built into the motor control device for determining the rotational position of the rotor is not specified at the initial stage of starting the motor, so the armature winding is There was a drawback that the ratio and magnitude of the current to be applied could not be specified, resulting in unstable control operations.

[Purpose of the invention]

An object of the present invention is to provide an electric motor control device and a control method thereof that can stabilize the electric current of the electric motor early in the initial stage of startup and proceed with reliable control.

[Summary of the invention]

A first invention of the present application includes: a drive device whose output is connected to an electric motor and controls the rotation of the electric motor; a rotation detection device that outputs a magnetic pole position information pulse and a rotation angle information pulse of a rotor of the electric motor; and the rotation angle. speed command means for calculating a value corresponding to a rotational speed deviation based on the information pulse and the speed target set value and outputting the calculated value to the drive device; based on the magnetic pole position information pulse and the rotation angle information pulse; An electric motor control device comprising: a position detection means for detecting a magnetic pole position of a rotor of the electric motor; and a phase command means for inputting an output signal of the position detection means and outputting a current phase command signal to the drive device, The position detecting means includes: a counting means for counting the rotation angle information pulse; a reset means for setting the output of the counting means to a predetermined value every 60 degrees based on the magnetic pole position information pulse; and a start signal is inputted thereto. The starting period from when the first change point of the magnetic pole position information pulse is input is the starting period in which a value corresponding to the center angle of the rotation angle range determined by the magnetic pole position information pulse is output. an address for sending an output signal of the addressing means at startup to the phase command means during the start period, and for sending an output signal of the counting means to the phase command means for a period beyond the start period; A second invention of the present application is a control device for an electric motor, characterized in that it is equipped with a selection means, and a second invention of the present application comprises: a drive device whose output is connected to an electric motor and controls rotation of the electric motor; and magnetic poles of a rotor of the electric motor. a rotation detection device that outputs a position information pulse and a rotation angle information pulse; and a speed that calculates a value corresponding to a rotation speed deviation based on the rotation angle information pulse and the speed target setting value and outputs the calculated value to the drive device. command means; position detection means for detecting the magnetic pole position of the rotor of the motor based on the magnetic pole position information pulse and the rotation angle information pulse; and inputting an output signal of the position detection means to apply current to the drive device. In a control method for starting operation of a motor control device equipped with a phase command means for outputting a phase command signal, at the time of starting, a value corresponding to a center angle of a rotation angle range determined by the magnetic pole position information pulse is set. , a first step of initially setting the position detecting means, and a timing at which the magnetic pole position information pulse changes within a range of rotation of at most 60 degrees after the motor starts rotating, corresponding to the rotation angle at that time. a second step of setting a value in the position detecting means; and after the second step, the position detecting means:
This control method is characterized by comprising a third step of counting the rotation angle information pulses.

[Embodiments of the invention]

Below, we will first explain the rotation detection device in Figures 2 and 3.
This will be explained using figures. Reference numeral 200 is a disc-shaped rotating body, on which a plurality of repeated patterns (tracks) coded on one surface are provided on concentric circles. Specifically, the plate surface 201 of a structure made of a plate-shaped aluminum material has a baked part and an unbaked part of the magnetic coating repeated at a certain period, and in the figure, the black belt part (or hatched part) is the magnetic coating. The areas where the paint film has been baked and the white bands indicate areas where the paint has not been baked. That is, the track 203 at the outermost diameter part of the rotating body 200
In this case, burnt portions and unburnt portions are repeatedly provided, which are subdivided into repeating periods having the resolution necessary to maintain the reading accuracy of the rotational speed of the rotating body 200. In the embodiment, 1024 pairs of repeated patterns of the printed portion and unprinted portion are provided. Next, each inner track 204, 205, 206 has a repetition period required to read the rotational position of the rotating body 200 (i.e., a number of repetitions equal to 1/2 the number of poles of the motor connected to it). There is a printed part and an unprinted part. Since the example is a rotation detection device combined with a three-phase two-pole motor,
Within each track 204, 205, 206, the baked and unbaked portions of the magnetic coating are set within a range of 180° when viewed from the center, and a phase difference of 120° is provided between each track. It consists of Reference numeral 100 denotes a detector disposed close to and facing the board surface 201 of the rotary body 200, and this detector 100 has respective tracks 203, 204, 20.
Magnetoresistive elements 101 to 111 made of permalloy material, for example, are provided corresponding to numerals 5 and 206, respectively. That is, the magnetoresistive elements 101-1
05 is arranged to face each of the tracks 203 to 206 and to be easily influenced by the magnetic coating. Further, the magnetoresistive elements 107 to 111 are placed in locations that are not easily affected by the magnetic influence of the respective tracks 203 to 206, and the magnetoresistive elements 101 to 111 are
5 in series to constitute these base resistors. Such magnetoresistive elements 101~
111 can be easily formed on the detector substrate by photo-etching or sputtering. With this configuration, for example, a constant voltage is applied to the series circuit of the magnetoresistive elements 101 and 107, and a change in voltage across the magnetoresistive element 107 is detected by passing the magnetic coating, that is, by passing the rotating body 20.
0 rotation state can be measured. Note that two sets of magnetoresistive elements 101 and 10 are provided on the track 203.
7, 102, and 108 are provided to detect the rotational direction of the rotating body 200. Therefore, the arrangement interval of the magnetoresistive elements 101 and 102 is
03 magnetic coating film baked, 1/2 of unbaked interval included
are selected.

The rotation detecting device configured as described above is connected to the opposite load side of the motor, that is, the rotating body 200 is connected to the rotor of the motor, and the detector 100 is arranged on the fixed part.
Various types of feedback information obtained by detecting voltage changes of the respective magnetoresistive elements 107 to 111 can be utilized for controlling operation of the motor. That is, in a control system that employs a 120 DEG energization control method for the motor, the motor 13 can be controlled in the same manner as already explained with reference to FIG. That is, the voltage value applied to the motor 13 is controlled based on the speed feedback information detected from the track 203, and the armature winding 7 of the motor 13 is controlled by a simple combination of the rotational position feedback information detected from the tracks 204 to 206.
It controls the phase of the current supplied to each phase.

In this way, the rotation detection device of the embodiment can simultaneously extract speed information and rotational position information of the rotating body, and compared to conventional devices that combine a speed generator and a position detector, the device It is possible to proceed with downsizing. Furthermore, since the accumulation of assembly errors in the device is reduced, highly reliable feedback signals can be obtained. In particular, in the embodiment, the pattern of each track of the rotating body and each magnetoresistive element of the detector can be arranged simultaneously using printing technology, so that the accuracy of the rotation detection device itself can be improved. Moreover, it is also possible to omit adjustment operations during assembly.

In the embodiments described above, a rotation detection device using a disk-shaped rotating body has been described, but in the present invention, a cylindrical rotating body is used, and each track is arranged concentrically and parallel to the cylindrical surface of the rotating body. You can also set it up. Furthermore, in the embodiment, one track for detecting the rotational position is provided for each motor, and the inside of this track is divided according to the number of poles of the motor. It is also possible to provide tracks with a 90° phase difference for each pair of magnetic poles. Of course, it is also possible to provide tracks corresponding to each number of magnetic poles and select the most appropriate track according to the number of magnetic poles of the motor to which it is connected. Furthermore, in the example, various signals were detected by a combination of a magnetic coating film and a magnetoresistive element, but this could be done by using a previously proposed Hall element or a combination of a light-transmitting rotating body and a photoelectric element. can also be realized. In this case as well, printing techniques can be used to apply a luminescent paint to a transparent plate to form a pattern as shown in FIG. 2, which has already been described.

Next, a description will be given with reference to FIGS. 4 and 5. We have already explained how to control the operation of a 120° energization control type control device based on each detection signal of the rotation detection device, but when using this for a 180° energization control type control device, there are additional steps. Some ingenuity will be needed.

Below, 3-phase armature winding 308U, 308V, 3
An example of controlling a two-pole motor 308 equipped with 0.08W is shown. Now, the voltages Eu, Ev, and Ew induced in each phase winding 308U, 308V, and 308W of the motor 308 are expressed as Eu=sin(ωt) Ev=sin(ωt−2/3π) Ew=sin(ωt−4/3π ), the line voltages Euv, Evw, and Ewu between each phase are Euv=√3sin(ωt+π/6) Evw=√3sin(ωt+π/6−2/3π) Ewu=√3sin(ωt+π/6−4/ 3π).

This relationship is shown in FIG. 4 using the same numbers. In the case of the 180° current control method, the induced voltage Eu,
It is known that smooth torque can be obtained by supplying a sinusoidal current with the same phase as Ev and Ew. Therefore, the induced voltages Eu, Ev,
It is sufficient to generate a command signal to supply a line voltage that is 30° in phase ahead of Ew, and to control the driving means of the motor 308 based on this command signal. Two methods can be considered for this purpose.
One is to connect the rotating body of the rotation detection device 309 in accordance with the magnetic pole arrangement of the rotor 321 so as to obtain a rotational position signal that is in phase with the induced voltage, and process the detected rotational position signal in some way. A method to obtain a signal with a phase lead of 30° from the induced voltage.
The other is to obtain a signal that is in phase with the line voltage.
The connecting position of the rotating body of the rotation detecting device 309 may be advanced by an angle equivalent to 30 degrees in electrical angle from the magnetic pole arrangement of the rotor 321, or the mounting position of the detector of the rotation detecting device 309 may be set to be advanced from the magnetic pole arrangement of the rotor 321 by an angle equivalent to 30 degrees in electrical angle. There is a method of proceeding and arranging each winding in the same way. In the embodiment, the method explained later is adopted. That is, in Figure 4,
Ru, Rv, and Rw are set by the rotation detection device 3 to obtain a rotational position signal in phase with the magnetic pole arrangement of the rotor 321.
Rotational position signal when 09 is connected, Ruv,
Rvw and Rwu may indicate rotational position signals when the rotation detection device 309 is devised and connected so as to obtain a rotational position signal in phase with the line voltage.

Now, let's start explaining the control device part.
The two-phase speed detection signals A and B read out from the track 203 of the rotation detection device 309 are transmitted to the quadrupling circuit 3.
After being input to 12 and processed to four times the frequency,
The F/V converter 313 converts the signal into an analog value speed feedback signal, and at a matching point 302 it compares it with the target signal from the target setting means 301 that has set the target operating speed of the motor 308. The two-phase speed detection signals A and B are sent to the forward/reverse determiner 3 at the same time.
11, and the rotation direction of the motor 308 is determined. This determination result is input to the up-down selection terminal U/D of the up-down counter 314, and depending on the determined rotational direction of the motor 308, addition or subtraction operation of the up-down counter 314 is selected. Further, the speed detection signal A is input to the clock input terminal CP of the up/down counter 314. Further, the rotational position signal Ruv detected from, for example, the track 204 of the rotation detection device 309 is waveform-shaped by a one-shot multivibrator and then input to the reset terminal RES of the up/down counter 314. In other words, the rotational position signal Ruv is input, and the
Assuming that the position where the down counter 314 is cleared to zero is the origin of the rotation system, the rotation position of the rotation system will correspond to the numerical value stored in the up/down counter 314 in a fixed relationship. Now, if we assume that the speed detection signal A generates 1024 pulses for one revolution of the motor 308, one pulse input to the up/down counter 314 will be generated by the motor 308.
This indicates a rotation of 360°/1024 of 8. Therefore, the rotation angle of the motor 308 can be determined by reading the value of the up/down counter 314 and multiplying this count by 360°/1024. This up/down counter 3
The count value of 14 is used as it is as an address signal for the next-stage sine wave tables 315 to 317. That is, the sine wave tables 315 to 31
The ROM constituting 7 stores in advance the values of various sine waves corresponding to the address signal (in other words, the rotation angle of the motor 308) and similar to each line voltage waveform required for control. Sine wave table 3
The digital signals output by 15 to 317 are converted into analog phase command signals by D/A converters 318 to 320, and then output to multipliers 325 to 327, and then inputted through speed control amplifier 303 to a matching point. It is multiplied together with the speed command signal of 302 and becomes the drive command signal of the inverter 337. The inverter 337 receives these drive command signals, controls the conduction of the power transistor group of the inverter section 337, and supplies the power transistors to the motor 308.
It controls the line voltage of each phase. Note that 305 and 306 in the inverter 337 are a current feedback matching point and a current control amplifier for continuing operation of the inverter 337 under an appropriate load condition.

By configuring the control device in this way, the line voltage and phase of the three-phase power supplied to the motor 308 can be maintained at appropriate conditions based on the signal from the rotation detection device 309, depending on the operating state of the motor 308. . That is, the 3
Since the phase power has a sinusoidal waveform with an appropriate phase relationship, the motor 308 can always obtain smooth torque. Further, since the necessary control operation can be performed without using a resolver that has been conventionally required, the detection device combined with the motor 308 can be downsized.

In the embodiment, a sine wave modulation signal for carrying out the 180° energization control method is generated by a combination of the up/down counter 314 and the sine wave tables 315 to 317, and errors and errors caused by the nozzles of the up/down counter 314 are generated. In order to prevent the count from accumulating, the up/down counter 314 is reset by capturing the rising edge of the rotational position signal Ruv of the rotation detection device 309. However, if more strict control is required, the rotation detection device 30
Rotational position signals Ruv, Rvw, issued from 9
It is also possible to use all of Rwu and provide combinations of up/down counters and sine wave tables for the number of phases. Furthermore, set the sine wave table to 1
The required sine wave value can also be found by providing only one set of up/down counters, adding and subtracting the address data of the up/down counter by a value corresponding to the phase difference of each phase, and inputting the resultant to the sine wave table.

Now, in the above embodiment, the motor 308
At the initial stage of startup, the up/down counter 3
Since the contents of the address signals output to each of the sine wave tables 315 to 317 are not specified until the reset signal is input to the reset terminal RES of 14, the control operation may become unstable.
As a countermeasure to this problem, FIG. 6 shows an embodiment of the present invention.
It is conceivable to adopt the method shown in Fig. 7. In other words, each rotational position signal is
From the signal status of Ruv, Rvw, and Rwu, motor 3
08 can be determined, and the address signal of each sine wave table corresponding to the rotation angle at the center of the uniquely determined rotation angle range can be obtained. To explain this in detail, for example, if the rotational position signals Ruv and Rwu are both generated as shown in FIG. Let 0° (360°) at the center of this be the rotation angle for controlling the motor 308. In FIG. 6, 400 is a rotational position discrimination circuit, and a start display switch 4 is closed at the initial stage of start.
01 signal, each rotational position signal Ruv,
From the Rvw and Rwu signals, address signals for each of the sine wave tables 315 to 317 as explained in FIG. 7 are uniquely determined and output. 402 is an address signal selection circuit, which selects the address signal of the rotational position determination circuit 400 when starting the motor 308, and selects the count result of the up/down counter 314 after starting the motor 308, and selects the count result of the up/down counter 314 to select each sine wave table 315 to 31.
7. Considering that the other parts whose explanations are omitted are the same as those of the embodiment already described, the address signals of each sine wave table 315 to 317 are uniquely set at the initial stage of startup (at least within one revolution of the motor 308). Since this is determined, control can be stabilized.

Furthermore, if you want to obtain accurate address signals at an early opportunity, you can use the rotational position signals Ruv, Rvw, Rwu and the signal from the forward/reverse determiner 311 to obtain accurate address signals every time the combination of the rotational position signals Ruv, Rvw, Rwu changes. The rotational position of the motor 308 is determined, and at the same time an address signal corresponding to this determined position is obtained, the up/down counter 314 is reset. After this, the count value of the up/down counter 314 is set to the value of the determined address signal. and add this addition result to each sine wave table 315 to 3.
It is also possible to configure the control circuit so as to use it as an address signal of 17. With this configuration, an accurate position signal can be obtained until the motor 308 rotates at least 60 degrees.

〔Effect of the invention〕

According to the present invention, there is an effect that sufficient rotational torque can be ensured at the initial stage of startup. In addition, accurate position signals can be obtained at an earlier opportunity during the initial startup period.
Since regular rotational torque can be ensured, stable control can be achieved in the initial stage of startup. Therefore, according to the present invention, the electric motor can be constantly controlled to the target state based on the extracted operating speed information and rotational position information.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining a conventional electric motor control device, FIG. 2 is a diagram for explaining essential parts of a rotation detection device according to an embodiment of the present invention, and FIG.
The figure is a further enlarged view of the main part of Figure 2, and Figure 4.
The figure shows various detection signals of the rotation detection device and voltage waveforms at various points on the motor, with the rotation angle of the motor rotor plotted on the horizontal axis. FIG. 5 explains one embodiment of the motor control device of the present invention. FIG. 6 is a block diagram for explaining essential parts of another embodiment, and FIG. 7 is a diagram for explaining the operation of FIG. 6. 101, 102, 103, 104, 105...detection element, 200... rotating body, 203, 204, 20
5,206...coded repeating pattern, 3
08...Electric motor, 309...Rotation detection device, 301,
302, 303, 312, 313... Speed command means, 310, 311, 314... Position detection means, 3
15,316,317,318,319,320
...Phase command means, 325, 326, 327, 33
7...Driving means.

Claims (1)

[Scope of Claims] 1. A drive device whose output is connected to an electric motor and controls the rotation of the electric motor; a rotation detection device that outputs magnetic pole position information pulses and rotation angle information pulses of a rotor of the electric motor; and the rotation angle. speed command means for calculating a value corresponding to a rotational speed deviation based on the information pulse and the speed target set value and outputting the calculated value to the drive device; based on the magnetic pole position information pulse and the rotation angle information pulse; An electric motor control device comprising: a position detection means for detecting a magnetic pole position of a rotor of the electric motor; and a phase command means for inputting an output signal of the position detection means and outputting a current phase command signal to the drive device, The position detection means includes a counting means for counting the rotation angle information pulses, a reset means for setting the output of the counting means to a predetermined value every 60 degrees based on the magnetic pole position information pulses, and a start signal is input thereto. The starting period from when the first change point of the magnetic pole position information pulse is input is the starting period in which a value corresponding to the center angle of the rotation angle range determined by the magnetic pole position information pulse is output. an address for sending an output signal of the addressing means at startup to the phase command means during the start period, and for sending an output signal of the counting means to the phase command means for a period beyond the start period; A control device for an electric motor, characterized by comprising selection means. 2. A drive device whose output is connected to an electric motor and controls the rotation of the electric motor; a rotation detection device that outputs a magnetic pole position information pulse and a rotation angle information pulse of the rotor of the electric motor; and the rotation angle information pulse and the speed target setting value. a speed command means for calculating a value according to the rotational speed deviation based on the rotational speed deviation and outputting the calculated value to the drive device; A control method for starting operation of a motor control device comprising: a position detecting means for detecting a position detecting means; and a phase command means for inputting an output signal of the position detecting means and outputting a current phase command signal to the drive device, At the time of starting, a first step of initially setting a value corresponding to the center angle of the rotation angle range determined by the magnetic pole position information pulse in the position detecting means; a second step of setting a value corresponding to the rotation angle at that time in the position detecting means at a timing when the magnetic pole position information pulse within the rotating range changes; and after the second step, the position detecting means:
A control method comprising a third step of counting the rotation angle information pulses.