JP3483789B2 - Drive device for brushless DC motor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless DC motor driving device which operates a brushless DC motor based on a position detection signal from a position detector provided in the brushless DC motor.

[0002]

2. Description of the Related Art An induced voltage constant is one of control parameters for controlling a brushless DC motor. Figure 1
6 shows a conventional measuring system for measuring the induced voltage constant of a brushless DC motor. In this FIG.
A brushless DC motor 2 to which the position detector 1 is attached is connected to a test motor 4 via a coupling 3, and the test motor 4 has a variable speed controllable variable speed. The device 5 is connected. The brushless DC motor 2 is connected to a measuring device 6 that measures the induced voltage generated by the brushless DC motor 2 and measures the speed from the position detection signal from the position detector 1.

However, when the brushless DC motor 2 is rotated by the test motor 4, the brushless DC motor 2 generates an induced voltage and the position detector 1 generates a position detection signal. Measures the induced pressure generated by the brushless DC motor 2, measures the speed from the position detection signal generated by the position detector 1, and calculates the induced voltage constant (induced voltage constant = induced voltage value / speed) from these. It is calculated and displayed on a display not shown.

By the way, a permanent magnet is used for the rotor of the brushless DC motor 2. The induced voltage of the brushless DC motor 2 varies due to variations in the material of the permanent magnets and magnetization. Brushless DC motor 2
In the driving device of No. 3, the brushless DC motor 2 is controlled by using the induced voltage constant as one of the control parameters. If the induced voltage varies, the control may be adversely affected and the motor characteristics may deteriorate. . for that reason,
Conventionally, in consideration of the variation of the induced voltage, the work of measuring the induced voltage and the speed of the completed brushless DC motor 2 one by one and confirming whether the induced voltage constant is within a predetermined range or not. Was needed.

Further, in the brushless DC motor, if the phase sequence of the stator winding and the phase sequence of the position detection signal of the position detector 1 do not match, the drive device cannot be operated. Therefore, conventionally, the measuring device 6 measures the induced voltage and confirms the phase sequence of the induced voltage and the phase sequence of the position detection signal from the position detector 1.

On the other hand, the position detector 1 attached to the brushless DC motor 2 must be arranged at a certain position with respect to the induced voltage of the brushless DC motor 2. Therefore, conventionally, the measuring device 6 measures the induced voltage as well as the position detection signal from the position detector 1 to determine whether or not the position detection signal is within a predetermined position range of the induced voltage. I am trying to do it.

[0007]

However, in the conventional configuration for measuring the induced voltage constant, the completed brushless DC motors 2 are set one by one in the measuring system shown in FIG. 16 or released. There was a problem that it was necessary and took a considerable amount of time. In addition, the induced voltage constant measured by the measuring device 6 needs to be input and set as a control parameter in the drive device corresponding to the brushless DC motor 2, which may cause a setting error at the time of input.

[0008] In addition, in the conventional configuration, place near detector 1
If the mounting position is not within the predetermined position range, it is necessary to mechanically adjust the mounting position of the position detector 1, and there is a problem that the adjusting work takes time.

The present invention has been made in view of the above circumstances, and a first object thereof is to provide a brushless DC motor drive device capable of automatically measuring an induced voltage constant of a brushless DC motor. It is in.

[0010]

A second object of the present invention is to provide a drive device for a brushless DC motor capable of confirming a mounting position of a position detector and automatically adjusting it when it is not within a predetermined position range. is there.

[0012]

According to a first aspect of the present invention, there is provided a brushless DC motor driving device which drives a brushless DC motor based on a position detection signal from a position detector provided in the brushless DC motor. In a brushless DC motor driving device, a voltage detecting means for detecting a terminal voltage of the brushless DC motor is provided, and a speed detecting means for detecting a speed of the brushless DC motor is provided.
After controlling so that the applied voltage to the brushless DC motor is accelerated to a preset steady voltage,
A control unit is provided to control the voltage application to the brushless DC motor so that the value of the induced voltage detected by the voltage detection unit and the speed detected by the speed detection unit when the voltage application to the brushless DC motor is cut off. It is characterized in that an induced voltage constant calculating means for calculating the induced voltage constant is provided.

According to this structure, the drive device itself automatically determines the induced voltage constant of the brushless DC motor, so that the brushless DC motor can be set or unset in a conventional measuring system. In addition, the time is not required, and it is possible to prevent an input setting error of the measured induced voltage constant to the driving device.

A brushless DC motor driving device according to a second aspect of the present invention is configured to drive the brushless DC motor based on a position detection signal from a position detector provided in the brushless DC motor. In, a voltage detecting means for detecting a terminal voltage of the brushless DC motor is provided, and a voltage cycle detecting means for detecting a cycle of a voltage detected by the voltage detecting means is provided, and an applied voltage to the brushless DC motor is preset. After controlling to accelerate to a steady voltage, a control means for controlling the voltage application to the brushless DC motor is cut off, and when the voltage application to the brushless DC motor is cut off, the voltage detection means detects the voltage. The induced voltage constant is calculated from the value of the induced voltage and the cycle detected by the voltage cycle detection means. Characterized by the configuration in which the induced voltage constant computing means for computing.

According to this structure, the same effect as that of the first aspect can be obtained, and the induced voltage constant can be easily obtained only by measuring the induced voltage waveform.

[0016]

[0017]

A brushless DC motor drive device according to a third aspect of the present invention includes a current detection unit that detects a current flowing through the brushless DC motor, and a control unit that controls the value of a steady voltage applied to the brushless DC motor to the current. It is characterized in that the current detected by the detection means is controlled to be smaller than the set current. With such a configuration, it is possible to apply a voltage to the brushless DC motor such that the brushless DC motor rotates at a speed sufficient to generate an induced voltage without applying an excessive voltage.

According to this structure, it is possible to apply a voltage to the brushless DC motor so that the brushless DC motor rotates at a speed sufficient to generate an induced voltage without applying an excessive voltage.

A brushless DC motor drive device according to a fourth aspect of the present invention is configured to drive the brushless DC motor based on a position detection signal from a position detector provided in the brushless DC motor. In, a current detecting means for detecting a current flowing through the brushless DC motor is provided, and the applied voltage to the brushless DC motor is controlled to accelerate until it reaches a preset steady voltage, and then is maintained at that steady voltage. A phase that changes the phase angle of the position detection signal until the value of the current detected by the current detection means becomes minimum after the applied voltage to the brushless DC motor is maintained at a steady voltage. It is characterized in that the angle changing means is provided.

With such a configuration, the phase angle of the position detection signal is changed until the value of the current detected by the current detection means is minimized, so that the mounting position of the position detector is within the predetermined position range. Even if it does not exist, it will be automatically adjusted, and the work and time for mechanically adjusting the mounting position of the position detector can be eliminated.

The drive device for a brushless DC motor according to claim 5, wherein the control means, the control such that the current detected by the current detection means the value of the constant voltage applied to the brushless DC motor becomes smaller than the setting current It is characterized in that it is configured to do. According to such a configuration, the claims
Even in the case of the fourth aspect, the same effect as that of the third aspect can be obtained.

According to a sixth aspect of the present invention, there is provided a brushless DC motor driving device, which is provided with a current detecting means for detecting a current flowing through the brushless DC motor, and a voltage applied to the brushless DC motor, a current obtained from the current detecting means,
The brushless DC motor is provided with motor constant calculating means for calculating a motor constant based on the speed obtained from the speed detecting means and the induced voltage constant obtained from the induced voltage constant calculating means, and based on the motor constant obtained from the motor constant calculating means. The configuration is characterized by providing a phase angle control means for controlling the phase angle of the voltage applied to the.

In general, when a combination with a brushless DC motor whose motor constant is unknown occurs, it is necessary to set the brushless DC motor in a dedicated measuring system, measure the motor constant, and set the input to the drive unit. is there. On the other hand, according to the configuration of the drive device of claim 7, since the motor constant is detected from the voltage, current, speed and induced voltage constant of the brushless DC motor, the original motor characteristics can be satisfied, Moreover, it is not necessary to set the brushless DC motor in a dedicated measuring system to measure the motor constant and then to release the setting, and it is possible to prevent an input setting error of the motor constant to the drive device.

According to a seventh aspect of the present invention, there is provided a brushless DC motor driving device including current detection means for detecting a current flowing through the brushless DC motor, and speed detection means for detecting a speed of the brushless DC motor. A motor constant calculating means for calculating a motor constant based on a voltage applied to the current, a current obtained from the current detecting means, a speed obtained from the speed detecting means, and an induced voltage constant obtained from the induced voltage constant calculating means, It is characterized in that a phase angle control means for controlling the phase angle of the voltage applied to the brushless DC motor based on the motor constant obtained from the motor constant calculation means is provided. With such a configuration, the same effect as that of the sixth aspect can be obtained even with the second aspect.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to FIGS. First,
The overall structure is shown in FIG. That is, the brushless DC motor 12 to which the position detector 11 composed of a rotary encoder is attached is connected to the load device 14 via the coupling 13, and the brushless DC motor 12 has a drive device 15 for driving and driving the brushless DC motor 12. Connected,
The drive unit 15 is connected to a commercial three-phase AC power supply 16. The position detector 11 is also connected to the drive unit 15.

FIG. 1 shows a specific structure of the driving device 15. In this drive device 15, the full-wave rectification circuit 1
The AC input terminal 7 is connected to the three-phase AC power supply 16, and the smoothing capacitor 18 is connected between the DC output terminals. The DC output terminal of the full-wave rectifier circuit 17 is connected to the input terminal of an inverter circuit 19 as a driving means, and the output terminal of the inverter circuit 19 has power supply lines 20, 21 and 2.
2 is connected to the input terminal of the brushless DC motor 12. Current transformers 23, 24 and 25 are arranged on the power supply lines 20, 21 and 22.

Here, the inverter circuit 19 is a well-known one constituted by connecting six IGBTs, which are switching elements, in a three-phase bridge. The brushless DC motor 12 has stator windings 12u, 12w, and 12v connected in a star configuration, and one terminal of each is connected to the power supply lines 20, 21 and 22 as an input terminal.

A control device 26 forming a part of the drive device 15.
Is mainly composed of a microcomputer, but is shown here as a functional block diagram. That is, the current detection circuit 27, which is the current detection means,
Each input terminal is connected to the current transformers 23, 24 and 25, and the output terminal is connected to the input terminal of the control circuit 28 as a control means, and the current detected by the current transformers 23, 24 and 25 is converted into a digital value. And is supplied to the control circuit 28. The voltage detection circuit 29, which is a voltage detection means,
Each input terminal is connected to each input terminal of the brushless DC motor 12, and the output terminal is connected to the input terminal of the control circuit 28. The terminal voltage of the brushless DC motor 12 is converted into a digital value and given to the control circuit 28. It is like this.

The speed detection circuit 30 serving as speed detection means has an input terminal connected to the output terminal of the position detector 11, an output terminal connected to the input terminal of the control circuit 28, and a pulse signal from the position detector 11. Is given to the control circuit 28 as a digital value. Further, in the induced voltage constant calculation circuit 31, which is an induced voltage constant calculation means, each input terminal is connected to each input terminal of the voltage detector 29 and the speed detection circuit 30, and the output terminal is connected to the input terminal of the control circuit 28. In addition, the induced voltage constant obtained later is given to the control circuit 28.

The output terminal of the position detector 11 is connected to the input terminal of the control circuit 28, and the control circuit 28 operates as described later and operates via the gate drive circuit 32 to drive each IGBT of the inverter circuit 19. An energization signal is applied to the gate of each IGBT to control ON / OFF of each IGBT.
The control power supply circuit 33 supplies the control power supply voltage obtained by stepping down the DC voltage rectified by the full-wave rectifier circuit 17 and smoothed by the smoothing capacitor 18 to a constant voltage to each circuit.

Next, the operation of this embodiment will be described.
First, a case where the brushless DC motor 12 is normally operated will be described. In this case, the speed command value Fr (see FIG. 1) is given to the control circuit 28 from speed command means (not shown). Then, the control circuit 28 generates an energization signal from the position detection signal supplied from the position detector 11 and supplies this to the gate of each IGBT of the inverter circuit 19 via the gate drive circuit 32 to control ON / OFF of each IGBT. Thus, the brushless DC motor 12 is driven, and the speed detected by the speed detection circuit 30 is compared with the speed command value Fr to perform PWM control so that the detected speed becomes the speed command value Fr. As a result, the brushless DC motor 12 drives the load device 16 at the speed commanded by the speed command value Fr.

Now, the case of obtaining the induced voltage constant of the brushless DC motor 12 prior to the normal operation of the brushless DC motor 12 will be described with reference to the flowchart of FIG. 3 and the waveform diagram of FIG. When the control circuit 28 is set to the induced voltage constant setting mode, the control circuit 28 starts (starts) the flowchart of FIG. 3. First, in the process step S1 of “setting of steady voltage”, the steady voltage V1 is set. The setting is made, and the process proceeds to the process step S2 of "start operation". In this processing step S2, the control circuit 28, as shown in FIG. 4A, the voltage applied to the brushless DC motor 12, that is, the inverter circuit 1
The inverter circuit 19 is controlled so that the output voltage VO of 9 rises from the state of 0 volt to the steady voltage V1, and the operation of the brushless DC motor 12 is started.

Next, the control circuit 28 proceeds to a judgment step S3 of "current <set current?", In which the current flowing through the brushless DC motor 12, that is, the current detection circuit 2 is determined.
The current IO detected by 7 is the preset current I1 set in advance.
(See FIG. 4 (d)) It is determined whether it is less than "YES".
When (IO <I1), "acceleration" processing step S4
Move to. It should be noted that the case where it is determined to be "NO" in the determination step S3 will be described later.

At the processing step S4, the control circuit 28 controls the inverter circuit 19 so that the output voltage VO rises toward the steady voltage V1 with a predetermined acceleration characteristic, and proceeds to the next "acceleration end?" Judgment step S5. Transition. At this time, the speed R of the brushless DC motor 12 is also shown in FIG.
It rises as shown in (b). In this judgment step S5, the control circuit 28 outputs the output voltage V of the inverter circuit 19.
It is determined whether or not the acceleration until O reaches the steady voltage VI is completed, and if "NO", the processing step S
Returning to step 5, when the result is "YES", the process proceeds to step S6 of "steady operation" (time t1 in FIG. 4). Control circuit 28
In this processing step S6, the output voltage VO is held so as to be the steady voltage V1, and the process proceeds to the judgment step S7 of "Is TI passed?".

At the time t1, the control circuit 28 causes a timer (not shown) to start the time counting operation of the time T1.
It is determined whether or not the timing operation of No. 1 is completed. If "NO", the process returns to step S6, and if "YES", the process moves to process step S8 of "interruption of inverter output voltage" (time t2 in FIG. 4). . In the processing step S8, the control circuit 28 stops the operation of the inverter circuit 19 so that the output voltage VO becomes zero (0). Therefore, at this time, the terminal of the brushless DC motor 12 is generated. The voltage becomes the induced voltage E of the brushless DC motor 12 (see FIG. 4C).

The induced voltage constant calculation circuit 31 proceeds to the processing step S9 of "voltage detection", and the voltage detection circuit 2
9 reads the terminal voltage of the brushless DC motor 12, that is, the induced voltage E, and further moves to the processing step S10 of "speed detection" to detect the speed R of the brushless DC motor 12 detected by the speed detection circuit 30. Read. Then, the induced voltage constant calculation circuit 31 proceeds to the next step S11 of “calculation of induced voltage constant”, and from the read value E1 of the induced voltage E and the value R1 of the speed R, the induced voltage constant = E1 / R1 ... (1) The induced voltage constant is calculated and stored in the memory of the control circuit 28 as a control parameter, and the operation ends.

By the way, when the control circuit 28 judges "NO" in the judgment step S3 of "current <setting current?", It shifts to the processing step S12 of "change of setting of steady voltage", and here, the processing step S1. After changing the steady-state voltage V1 set in step 1 to a steady-state voltage lower than this to make a new steady-state voltage V1, the process returns to the determination step S3. When it is determined "NO" in this determination step S3, the processing step S12 is performed until "YES" is determined.
Will be repeated.

That is, the steady-state voltage V1 is of such a magnitude that the brushless DC motor 12 can generate an induced voltage of a sufficiently measurable value, and is not excessive for the brushless DC motor 12 (overcurrent does not flow). ) It is controlled to be set to a size.

As described above, according to this embodiment, after the preset steady voltage V1 is applied to the brushless DC motor 12, it is generated in the brushless DC motor 12 when the voltage application to the brushless DC motor 12 is cut off. Since the induced voltage constant is automatically obtained from the value E1 of the induced voltage E and the value R1 of the speed R at that time, unlike the conventional method, each completed brushless DC motor is set in the measurement system. Moreover, the work and time for releasing the set are unnecessary, and further, the drive device 15 for the measured induced voltage constant is measured.
It is also possible to prevent an input setting error with respect to, and obtain the original motor characteristics.

Moreover, after the steady voltage V1 is applied to the brushless DC motor 12 for a certain period of time T1 and then held, the voltage application to the brushless DC motor 12 is cut off to induce the induced voltage E.
Since the brushless DC motor 12 is rotated at a speed sufficient to obtain the induced voltage when the voltage application is interrupted, the brushless DC motor 12 is sufficiently operated to calculate the induced voltage constant. The induced voltage value can be obtained.

Further, when the current IO flowing through the brushless DC motor 12 after the start of operation of the brushless DC motor 12 is equal to or greater than the set current I1, the setting of the steady voltage V1 is changed so as to be less than the set current I1. The steady-state voltage V1 is set to such a value that the brushless DC motor 12 can generate an induced voltage of a sufficiently measurable value and is not too large for the brushless DC motor 12 (no overcurrent flows). There is an advantage of being controlled as described above.

5 to 7 show a second embodiment of the present invention. The same parts as those of the first embodiment are designated by the same reference numerals, and different parts will be described below. First, FIG.
Referring to FIG. 5, the drive device 34 in place of the drive device 15 has a control device 35 in place of the control device 26 as a part of the configuration. In the drive device 35, the voltage cycle detection circuit 36 serving as the voltage cycle detection means is , The input terminal is the voltage detection circuit 29
Is connected to one output terminal of the induced voltage constant calculating circuit 37, which is an induced voltage constant calculating means, and operates as will be described later. The induced voltage calculation circuit 37 has the other input terminal connected to the output terminal of the voltage detection circuit 29, and the output terminal connected to the input terminal of the control circuit 28, which also operates as described later. There is.

Next, the operation of the second embodiment will be described with reference to the flowchart of FIG. 6 and the waveform diagram of FIG. The control circuit 28 performs the same operation as that of FIG. 3 up to step S8 in the flowchart of FIG. here,
If the induced voltage E detected by the voltage detection circuit 29 has a waveform as shown in FIG. 7, the induced voltage constant calculation circuit 37
Reads the value (maximum value) E2 of the induced voltage E from the voltage detection circuit 29 in the processing step S9 of "voltage detection", and the induced voltage from the voltage cycle detection circuit 36 in the next processing step S13 of "cycle detection". The period T2 of E is read.

Then, the induced voltage constant calculating circuit 37 proceeds to the next step S14 of "calculation of induced voltage constant", and the induced voltage constant is expressed as: induced voltage constant = E2 / {(1 / T2) × (60 / Pn)} ... (2) Pn: Calculated like a pole number pair of the rotor in the brushless DC motor 12, and give it to the control circuit 28 to store it in the memory as a control parameter.

Therefore, the same effect as that of the first embodiment can be obtained by the second embodiment, and the induced voltage of the brushless DC motor 12 can be obtained only by detecting the waveform of the induced voltage E of the brushless DC motor 12. There is an advantage that the constant can be calculated.

FIGS. 8 to 11 show a third embodiment of the present invention. The same parts as those of the second embodiment are designated by the same reference numerals, and different parts will be described below. First, referring to FIG. 8, the drive device 38 instead of the drive device 34 is
A control device 39 in place of the control device 35 is part of the configuration. In this drive device 39, the rotation speed arrival detection circuit 40, which is the rotation speed arrival detection means, has an input terminal connected to the output terminal of the voltage detection circuit 29. The output terminal is connected to the output terminal of the control circuit 28 and operates as described later. Phase sequence switching circuit 41 serving as phase sequence switching means
Has an input terminal connected to the output terminal of the rotation speed arrival detection circuit 40 and an output terminal connected to the input terminal of the control circuit 28, which also operates as described later.

Next, the operation of the third embodiment will be described with reference to the flowchart of FIG. 9 and the waveform diagrams of FIGS. 10 and 11. The control circuit 28 performs the same operation as that of FIG. 3 up to step S7 in the flowchart of FIG.
After that, the rotation speed arrival detection circuit 40 proceeds to the “speed detection” processing step S15, reads the speed R detected by the speed detection circuit 30, and proceeds to the next “speed <set speed?” Determination step S16. To do. Rotation speed arrival detection circuit 40
In this judgment step S16, it is judged whether or not the speed R is less than a preset speed R2 (see FIGS. 10 and 11). In this embodiment, the set speed R2 is set to be smaller than the speed value R1 expected when the steady voltage V1 is applied to the brushless DC motor 12.

In the brushless DC motor 12, the phase sequence of the stator windings 12u, 12v, 12w and the position detector 1
If the phase sequence of the position detection signal from 1 is the same,
As shown in 0 (b), the speed R of the brushless DC motor 12 reaches or exceeds the set speed R2 when the time T1 elapses. For example, the power lines 20, 21, 22 and the input terminals of the brushless DC motor 12 are When the phase sequence of the stator windings 12u, 12v, 12w and the phase sequence of the position detection signal from the position detector 11 do not match due to incorrect connection of
As shown in 1 (b), the speed R does not reach the set speed R2 even when the time T1 has elapsed. In FIG. 11, the brushless DC motor 12 is an example in which a vibration phenomenon in which the brushless DC motor 12 repeats forward and reverse rotations in small increments is generated, and the current IO flowing in the brushless DC motor 12 also fluctuates relatively large.

Therefore, the rotation speed arrival detection circuit 40 is shown in FIG.
When the phase sequence is normal as indicated by 0, it is judged "NO" in the judgment step S16 of "speed <set speed?", And a signal to that effect is sent to the control circuit 28.
The process moves to the processing step S17 of "cutoff of inverter output voltage" and the operation of the inverter circuit 19 is stopped. On the other hand, when the rotational speed arrival detection circuit 40 has an abnormal phase sequence as shown in FIG.
"ES", and a signal indicating this is sent to the phase sequence switching circuit 41.
Then, the phase order switching circuit 41 sends a phase order switching signal to the control circuit 28. As a result, the control circuit 28 proceeds to the processing step S19 of "change phase sequence" through the processing step S18 of "cutoff of the inverter output voltage" which performs the same operation as the processing step S17.

The control circuit 28 performs this processing step S19.
In step S2, the phase sequence of the energization signals given to the inverter circuit 19 is processed so as to be changed from the previous one, and then the process returns to the "operation start" processing step S2. Hereinafter, although the above-described operation is repeated, the brushless DC motor is U,
In the case of 3 phases of V and W phases, there are only 6 combinations of phase orders, and therefore, the phase order of both can be matched by repeating 5 times at maximum.

Since the third embodiment is provided with the voltage cycle detection circuit 36 and the induced voltage constant calculation circuit 37, the second embodiment after the automatic adjustment of the phase sequence as in this embodiment is performed. It is preferable to perform the calculation of the induced voltage constant similar to the embodiment.

As described above, according to the third embodiment, the applied voltage of the brushless DC motor 12 is maintained at the preset steady voltage V1, and the speed R detected by the speed detection circuit 30 at that time is set to the set speed. If it has not reached R2 or higher,
That is, the stator winding 12u of the brushless DC motor 12,
If the phase sequence of 12v and 12w does not match the phase sequence of the position detection signal of the position detector 11, the phase sequence of energization to the brushless DC motor 12 is switched, so that the stator winding 12
It is possible to eliminate the work of replacing the phases of u, 12v, and 12w and the time.

12 to 14 show a fourth embodiment of the present invention. The same parts as those of the third embodiment are designated by the same reference numerals, and different parts will be described below. First,
Referring to FIG. 12, a drive device 42 that replaces the drive device 38.
Has a control device 43 instead of the control device 39 as a part of the configuration. In the drive device 43, one input terminal of a phase angle changing circuit 44, which is a phase angle changing means, is an output terminal of the position detector 11. The other input terminal is connected to the output terminal of the current detection circuit 27, and the output terminal is connected to the control circuit 2
It is connected to eight input terminals and operates as will be described later.

Next, the operation of the fourth embodiment will be described with reference to the flowchart of FIG. 13 and the waveform diagram of FIG. In the brushless DC motor 12, the current IO becomes the minimum value when the mounting position of the position detector 11 is within the determined position range, but when the mounting position is not within the determined position range, the current IO is reduced. Will be larger than this. In this embodiment, by utilizing such an action, the phase angle of the position detection signal of the position detector 11 is adjusted so that the current IO becomes the minimum value.

The control circuit 28 performs the same operation as that of FIG. 3 up to step S7 in the flowchart of FIG. After that, the phase angle changing circuit 44 proceeds to processing step S20 of “current detection”, where the current detection circuit 27
The value of the current IO detected by, for example, Aa is read (time t2 in FIG. 14). Next, the phase angle changing circuit 44 proceeds to the processing step S21 of “adjustment of phase angle”, in which the phase angle of the position detection signal detected by the position detector 11 is changed from the initial zero (0) to PH1. And the adjusted (changed) position detection signal is applied to the control circuit 28. Therefore, the control circuit 28 generates and operates the energization signal for the inverter circuit 19 based on the adjusted position detection signal.

After a lapse of a fixed time, the phase angle changing circuit 44 proceeds to the processing step S22 of "current detection" to read the value Ab of the current IO (time t3 in FIG. 14), and further,
Judgment step S23 of "Is the current value the minimum value?"
Move to. In this determination step S23, the phase angle changing circuit 44 compares the value of the current IO detected last time, the value of the current IO detected this time, and the value of the current IO detected next time, and the value of the current IO becomes the minimum value. Whether or not it is determined, and for the time being, it is determined to be "NO" here, and the process returns to step S21.

The phase angle changing circuit 44 executes the processing step S2.
Returning to 1, the phase angle of the position detection signal detected by the position detector 11 is adjusted from PH1 to PH2, and the adjusted position detection signal is given to the control circuit 28. Therefore, the control circuit 2
8 is an inverter circuit 19 based on the adjusted position detection signal.
To generate an energization signal for the operation (time t in FIG. 14).
Four ). After the elapse of a certain period of time, the phase angle changing circuit 44 shifts again to the processing step S22 of “current detection” and the current I
The value Ac of O is read (time t5 in FIG. 14), and the process proceeds to the determination step S23 of "whether the current value has reached the minimum value?".

Therefore, the phase angle changing circuit 44 determines the values Aa, Ab, Ac of the current IO in this judgment step S23.
And Ab <Aa, Ab <Ac (3), the value Ab is judged to be the minimum value, and the minimum value A
The phase angle PH1 that gives b is determined as the adjustment angle of the position detection signal. When such a determination is made, the control circuit 28
Is the processing step S2 of "cutoff of inverter output voltage"
4, the operation of the inverter circuit 19 is stopped (time t6 in FIG. 14). In the above case, the phase angle changing circuit 44 repeats steps S21, S22 and S23 until the above expression (3) is not satisfied.

Since the fourth embodiment is provided with the cycle detection circuit 36, the induced voltage constant calculation circuit 37, the rotation speed arrival detection circuit 40 and the phase sequence switching circuit 41, it is different from the third embodiment. After adjusting the phase sequence in the same manner, the phase angle of the position detection signal is adjusted as in this embodiment, and thereafter, the same calculation of the induced voltage constant as in the second embodiment is preferably performed. Is.

According to the fourth embodiment, after the applied voltage of the brushless DC motor 12 is kept at the steady voltage V1, the current detector 10 detects the current IO until the value of the current IO reaches a minimum value. Since the phase angle of the position detection signal is adjusted to be changed, the position detector 11 can be automatically adjusted even when the position of the position detector 11 is not within the predetermined position range. The work and time for mechanically adjusting the position can be eliminated.

FIG. 15 shows a fifth embodiment of the present invention, in which the same parts as those in the fourth embodiment are designated by the same reference numerals,
The different parts will be described below. The drive device 45 in place of the drive device 42 has a control device 46 in place of the control device 43 as part of its configuration. In this drive device 46, a motor constant calculation circuit 47, which is a motor constant calculation means, has input terminals The output terminals of the current detection circuit 27, the induced voltage constant calculation circuit 37, and the speed detection circuit 30 are respectively connected, and the output terminals are connected to the input terminals of the phase angle control circuit 48 which is the phase angle control means. The output terminal of the phase angle control circuit 48 is connected to the input terminal of the control circuit 28, and this also operates as described later.

Next, the operation of the fifth embodiment will be described. The motor constant calculation circuit 47 calculates a motor constant from the current detected by the current detection circuit 27, the induced voltage constant detected by the induced voltage constant calculation circuit 37, and the speed detected by the speed detection circuit 30. This calculated motor constant is given to the phase angle control circuit 48, and its control information is given to the control circuit 2.
8, and the control circuit 28 appropriately controls the phase angle of the voltage applied to the brushless DC motor 12 based on this. Here, the voltage equation and the torque equation of the brushless DC motor 12 are shown in the following equations (4) and (5).

[0064]

[Equation 1] Where ω is the electrical angular velocity, id and iq are the armature current d
Axis and q-axis components, Vd and Vq are d-axis and q-axis components of armature voltage, ψa is (3/2) ^1/2 × (maximum value of permanent magnet armature flux linkage), and R is armature Resistance, Ld and Lq
Is the d-axis and q-axis inductance, p is the differential operator, Pn
Is the number of pole pairs and T is torque.

In the equation (5), the first term on the right side is the magnet torque generated by the magnetic flux and the armature current from the permanent magnet, and the second term on the right side is the reluctance torque generated by the saliency. Depending on the structure of the brushless DC motor 12, the d-axis and q-axis inductances Ld and Lq are Ld =
In some cases, the reluctance torque of the second term on the right side does not occur. In addition, the brushless DC motor 1 that generates the reluctance torque of the second term on the right side
Even when the control value is 2, the control method changes depending on the values of the d-axis and q-axis inductances Ld and Lq in consideration of high efficiency operation. For example, there is a method in which the phase angle of the output voltage of the inverter circuit 19 is changed according to the change of the load or the change of the speed, and the phase relationship between the voltage and the current of the brushless DC motor 12 is advanced to bring it into the phase state. The values of the d-axis and q-axis inductances Ld and Lq are related to this phase relationship.

When the brushless DC motor 12 connected to the drive unit 45 has a one-to-one combination and the motor constant is known in advance, the original motor characteristic can be obtained by presetting the optimum control constant for the motor constant. Obtainable. However, if a combination with the brushless DC motor 12 whose motor constant is unknown occurs, it is necessary to measure the motor constant in order to obtain the original motor characteristics. Therefore, in this embodiment, the motor constant is obtained using the equation (4).

That is, the electrical angular velocity ω is calculated by the velocity detection circuit 30.
Obtained from The d-axis and q-axis components id and iq of the armature current are obtained from the current detection circuit 27. The d-axis and q-axis components Vd and Vq of the armature voltage are output from the inverter circuit 19
It is known because it is the voltage being output by. ωψa
Corresponds to the induced voltage, the induced voltage constant calculation circuit 3
7 and the speed detection circuit 30. Armature resistance R
Can be obtained by calculating the current value obtained from the current detection circuit 27 when the DC voltage is supplied to the brushless DC motor 12 and the DC voltage value thereof. Therefore, d
The axial and q-axis inductances Ld and Lq can be obtained by the equation (4).

Using the motor constants thus obtained, for example, the function of the following equation (6) is used as the control parameter of the phase angle, and the voltage supplied to the brushless DC motor 12 by the phase angle control circuit 48 is The phase angle can be controlled. φl = Kl × (load factor) × (speed factor) × (Lq / Ld) (6) where φl is a phase angle for changing the phase of the output voltage of the inverter circuit 19, Kl is a phase coefficient, and a load factor. Is the torque ratio to the motor rated torque, and the speed ratio is the speed ratio to the motor rated speed.

According to the fifth embodiment, the motor constant is detected from the voltage, current, speed and induced voltage constant of the brushless DC motor 12, and the phase angle for changing the phase of the output voltage of the inverter circuit 19 is calculated. I decided to do so,
The original motor characteristics can be satisfied, and the work and time for releasing the setting after setting the brushless DC motor 12 in a dedicated measuring system and measuring the motor constants are unnecessary. It is possible to prevent an input setting error in the device 45.

The present invention is not limited to the embodiments described above and shown in the drawings, and the following expansions and modifications are possible. In the configuration of FIG. 8 (third embodiment), FIG. 12 (fourth embodiment) and FIG. 15 (fifth embodiment), a diagram is shown instead of the rotation speed arrival detection circuit 36 and the induced voltage constant calculation circuit 37. The induced voltage constant arithmetic circuit 31 shown in No. 2 (first embodiment) may be provided. In the flowchart of FIG. 3 (first embodiment), FIG. 6 (second embodiment), FIG. 9 (third embodiment) and FIG. 13 (fourth embodiment),
The determination step S3 and the processing step S12 may be provided as needed. In the first to fifth embodiments, the steady voltage is set to the equal voltage V1, but it may be set to a voltage suitable for each embodiment. In the third embodiment (FIGS. 8 to 11), the set speed (R2) is set to the steady speed R when the steady voltage V1 is applied.
It may be set to 1.

[0071]

As is clear from the above description, the present invention can obtain the following effects. According to the brushless DC motor drive device of claim 1, an induced voltage generated in the brushless DC motor when the voltage application to the brushless DC motor is cut off after applying a preset steady voltage to the brushless DC motor. Since the induced voltage constant is automatically obtained from the value of and the speed at that time, the work and time for setting and releasing the completed brushless DC motor in the measurement system one by one becomes unnecessary, Moreover, it is possible to prevent an input setting error of the measured induced voltage constant with respect to the driving device.

According to the brushless DC motor driving device of the second aspect, after the steady voltage is applied to the brushless DC motor, the induced voltage generated in the brushless DC motor is cut off when the voltage application to the brushless DC motor is cut off. Since the induced voltage constant is automatically obtained from the value and its cycle, the same effect as that of the first aspect can be obtained, and in particular, the induced voltage constant can be measured only by measuring the induced voltage waveform of the brushless DC motor. There is an advantage that a constant can be obtained.

[0073]

According to the brushless DC motor driving device of the third or fifth aspect, the steady voltage applied to the brushless DC motor is set so that the current detected by the current detecting means is smaller than the set current. Therefore, it is possible to apply a voltage to the brushless DC motor such that the brushless DC motor rotates at a speed sufficient to generate an induced voltage without applying an excessive voltage.

According to the brushless DC motor driving device of the fourth aspect , the phase of the position detection signal is maintained until the value of the current detected by the current detecting means becomes minimum after the applied voltage of the brushless DC motor is maintained at a steady voltage. Since the angle is changed, the position detector mounting position can be automatically adjusted even when it is not within the specified position range, and the position detector mounting position can be mechanically adjusted. And time can be eliminated.

According to the brushless DC motor driving device of the sixth or seventh aspect, the motor constant is detected from the voltage, current, speed and induced voltage constant of the brushless DC motor, so that the original motor characteristics are satisfied. Moreover, it is not necessary to set the brushless DC motor in a dedicated measuring system to release the setting after measuring the motor constants, and there is no need to input the motor constants into the drive unit. Can be prevented.

[Brief description of drawings]

FIG. 1 is a detailed block diagram of a drive device showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing the overall configuration.

FIG. 3 is a flowchart showing control contents.

FIG. 4 is a waveform diagram of each part for explaining the operation.

FIG. 5 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 6 is a view corresponding to FIG.

[FIG. 7] Waveform diagram of induced voltage

FIG. 8 is a diagram corresponding to FIG. 1 showing a third embodiment of the present invention.

FIG. 9 is a view corresponding to FIG.

FIG. 10 is a view corresponding to FIG. 4 (No. 1).

FIG. 11 is a view corresponding to FIG. 4 (No. 2).

FIG. 12 is a view corresponding to FIG. 1 showing a fourth embodiment of the present invention.

FIG. 13 is a view corresponding to FIG.

FIG. 14 is a view corresponding to FIG.

FIG. 15 is a view corresponding to FIG. 1 showing a fifth embodiment of the present invention.

FIG. 16 is a block diagram showing a conventional measuring system for measuring an induced voltage constant.

[Explanation of symbols]

In the drawings, 11 is a position detector, 12 is a brushless DC motor, 15 is a drive device, 19 is an inverter circuit, 26 is a control device, 27 is a current detection circuit (current detection means), 28 is a control circuit (control means), Reference numeral 29 is a voltage detection circuit (voltage detection means), 30 is a speed detection circuit (speed detection means), 31 is an induced voltage constant calculation circuit (induced voltage constant calculation means), 32
Is a gate drive circuit, 34 is a drive device, 35 is a control device,
36 is a voltage cycle detection circuit (voltage cycle detection means), 37 is an induced voltage constant calculation circuit (induced voltage constant calculation means), 38
Is a drive device, 39 is a control device, 40 is a rotation speed arrival detection circuit (rotation speed arrival detection means), 41 is a phase sequence switching circuit (phase sequence switching means), 42 is a drive device, 43 is a control device, and 44 is a phase. Angle changing circuit (phase angle changing means), 45 is a driving device,
Reference numeral 46 is a control device, 47 is a motor constant calculation circuit (motor constant calculation means), and 48 is a phase angle control circuit (phase angle control means).

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisanori Shibata 2121 No. 21, Osamu, Asahi-cho, Mie-gun, Mie Prefecture, Toshiba Mie Plant (56) Reference JP-A-56-115189 (JP, A) JP-A 9-197027 (JP, A) JP-A-6-284782 (JP, A) JP-A-6-269191 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02P 6/24

Claims (7)

(57) [Claims] 1. A brushless DC motor drive device for operating a brushless DC motor based on a position detection signal from a position detector provided in the brushless DC motor, wherein a terminal voltage of the brushless DC motor is detected. Voltage detecting means, a speed detecting means for detecting the speed of the brushless DC motor, and after controlling so that the applied voltage to the brushless DC motor is accelerated to a preset steady voltage,
Control means for controlling the voltage application to the brushless DC motor so as to be cut off; and a value of the induced voltage detected by the voltage detection means and a speed detected by the speed detection means when the voltage application to the brushless DC motor is cut off. And an induced voltage constant calculating means for calculating the induced voltage constant from the brushless DC motor. 2. A brushless DC motor drive device for operating a brushless DC motor based on a position detection signal from a position detector provided in the brushless DC motor, wherein a terminal voltage of the brushless DC motor is detected. And a voltage cycle detecting means for detecting the cycle of the voltage detected by the voltage detecting means, and after controlling so that the applied voltage to the brushless DC motor is accelerated to a preset steady voltage,
Control means for controlling the voltage application to the brushless DC motor so as to be cut off; a value of the induced voltage detected by the voltage detection means and a cycle detected by the voltage cycle detection means when the voltage application to the brushless DC motor is cut off. An apparatus for driving a brushless DC motor, comprising: an induced voltage constant calculating means for calculating an induced voltage constant from 3. The current flowing through the brushless DC motor is detected.
And a control means for controlling the brush level.
The value of the steady voltage applied to the DC motor is
Make the current detected by the output means smaller than the set current.
Claims characterized in that it is configured to control
The drive device for the brushless DC motor according to 1 or 2 . 4. A position disposed on a brushless DC motor
Based on the position detection signal from the detector, brushless DC
A brushless DC motor designed to drive a motor
In the device, a current for detecting the current flowing in the brushless DC motor
Detection means and applied voltage to the brushless DC motor are preset
After controlling to accelerate until it reaches the set steady voltage,
Control means for controlling so that the steady voltage is maintained, and the applied voltage to the brushless DC motor is a steady voltage.
The value of the current detected by the current detecting means after being kept at
Change the phase angle of the position detection signal until it becomes minimum
A brushless DC motor driving device comprising a phase angle changing means . 5. The control means prints on a brushless DC motor.
The value of the applied steady voltage is the current detected by the current detection means.
Is controlled to be smaller than the set current.
The brushless DC motor drive device according to claim 4, wherein 6. The current flowing through the brushless DC motor is detected.
Current detecting means for outputting, voltage applied to the brushless DC motor, the current
Current obtained from detection means, obtained from speed detection means
The induced voltage constant obtained from the speed and induced voltage constant calculation means
Motor constant calculating means for calculating a motor constant based on a number
If, based on the motor constant obtained from the motor constant calculating means
Phase angle of voltage applied to the brushless DC motor
Brushless DC motor driving device according to claim 1, characterized by including a phase angle control means for controlling. 7. A current detecting means for detecting a current flowing through a brushless DC motor, and a speed detecting means for detecting a speed of the brushless DC motor.
Calculating a motor constant based on the stage and the voltage applied to the brushless DC motor, the current obtained from the current detecting means, the induced voltage constant derived from the speed and the induced voltage constant calculating means obtained from the speed detecting means a motor constant calculating means, according to claim 2, characterized in that it includes a phase angle control means for controlling the phase angle of the voltage applied to the brushless DC motor based on the motor constant obtained from the motor constant calculating means Brushless DC motor drive.