JP2001037279A - Inverter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct the conduction phase of a permanent magnet motor optimally through a simple arrangement without requiring any complicated operation and to drive a permanent magnet motor with low vibration and noise. SOLUTION: A pulse generating circuit 11 generates 32 clock pulses CK within a variation period T of positional signals Hu-Hw, and a phase estimation circuit 12 counts the clock pulses CK with reference to the leading edge of the positional signal Hu to estimate the phase of the rotor 6R of a permanent magnet motor 6. A voltage signal forming circuit 13 forms a voltage signal VSIN having the amplification factor of a sine wave depending on the detailed phase of the rotor 6R and a drive signal forming circuit 14 outputs a conduction signal waveform based on the voltage signal VSIN. A phase correction circuit 9 corrects the conduction phase by setting a phase correction value PC in a counter of the phase estimation circuit 12 at the leading edge of the positional signal Hu.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter for driving and controlling a permanent magnet motor having a load such as a fan or a pump.

[0002]

One of the driving methods in this type of inverter device is to detect a position of a rotor of a brushless motor as a permanent magnet motor, obtain a position signal, and fix the position signal based on the position signal. There is one that determines an energization phase angle (commutation timing) with respect to a child winding. In such a driving method, there is a problem that the phase of the position signal is shifted according to the number of rotations of the motor, the load torque, and the like, so that the phase of the energization is also shifted and the efficiency of the motor is reduced.

[0003] As a conventional technique for solving this problem, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 7-111595. In this conventional technique, the rotation speed and load torque of a motor are detected, and a microcomputer reads a correction phase value corresponding to the detected values from a data map of a storage device. Then, by calculating a time corresponding to the correction phase value and correcting the output timing of the energization switching signal, the motor is energized at an optimal phase and driven at 120 °.

However, in this prior art,
In order to obtain a time corresponding to the correction phase value, the microcomputer needs to perform a complicated operation, and it is necessary to create a control program for performing the operation. Further, in order to perform the calculation, a storage device for storing various data including a map is required. Further, even when the phase is optimally corrected, the motor is energized at 120 ° by a rectangular wave, so that there is a problem that vibration and noise are generated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to optimally correct the energizing phase to a permanent magnet motor with a simple configuration without performing complicated calculations, An object of the present invention is to provide an inverter device that can drive a magnet motor with low vibration and low noise.

[0006]

In order to achieve the above object, an inverter device according to the present invention is characterized in that induction induced in a plurality of phases of stator windings in accordance with the rotational position of a rotor constituting a permanent magnet motor. Position signal output means for outputting a position signal having a fixed phase relationship with respect to voltage; cycle measurement means for measuring a change cycle of the position signal; pulse generation for generating a plurality of clock pulses within the change cycle Means for counting the number of occurrences of the clock pulse, phase estimating means for estimating a phase of the rotor based on a count value of the counter with reference to a timing at which the position signal changes, and the timing A phase correction means for setting a correction value to the counter to correct the phase of the rotor; and forming a predetermined voltage signal according to the phase of the rotor. A voltage signal forming means for, PW
A carrier generating means for generating a carrier of the M signal; a driving signal forming means for comparing a signal level of the voltage signal with a signal level of the carrier to form a driving signal; and And a driving means for supplying current to the phase stator winding.

With such a configuration, the pulse generating means generates a plurality of pulses within the change period of the position signal, and the phase estimating means counts the number of clock pulses generated by the pulse generating means by the counter. Then, the phase of the rotor is estimated based on the count value of the counter based on the timing at which the position signal changes, and the voltage signal forming means forms a predetermined voltage signal according to the phase of the rotor.

That is, since the phase of the rotor can be obtained with a more detailed resolution than the change period of the position signal, the voltage signal forming means generates the permanent magnet motor in accordance with the detailed phase of the rotor. It is possible to form a voltage signal capable of suppressing vibration, noise, and the like more than a 120 ° conduction signal. Further, the phase correction means corrects the phase by setting a correction value to the counter at the reference timing of the position signal, so that the phase correction means can perform appropriate operations without performing a complicated operation or using a storage device for storing data. It is possible to energize the stator winding at an appropriate commutation timing.

In this case, it is preferable that the voltage signal formed by the voltage signal forming means is sinusoidal, and the vibration generated in the permanent magnet motor can be obtained. , Noise and the like can be suppressed as much as possible.

According to a third aspect of the present invention, there is provided a rotation speed detecting means for detecting a rotation speed of a permanent magnet motor and outputting a voltage signal corresponding to the detected rotation speed, and an output of the rotation speed detection means. A / D for A / D converting a voltage signal
Conversion means, and the phase correction means may be configured to use the digital data output by the A / D conversion means as a correction value. With such a configuration, the phase correction unit can correct a phase shift that fluctuates according to the rotation speed of the permanent magnet motor. Further, by directly setting the A / D conversion value of the voltage signal as the correction value in the counter, the calculation becomes unnecessary, the configuration is simplified, and the correction process can be performed in a short time.

Further, as set forth in claim 4, torque detecting means for detecting torque of the permanent magnet motor and outputting a voltage signal corresponding to the detected torque, and a voltage signal output by the torque detecting means. A / D for A / D conversion
It is preferable to include a conversion unit, and to configure the phase correction unit to use the digital data output by the A / D conversion unit as a correction value.

With this configuration, the A / D conversion value of the voltage signal corresponding to the torque detection level of the permanent magnet motor is set as a correction value in the counter of the phase estimating means.
The phase can be corrected according to the torque fluctuation of the permanent magnet motor.

In this case, as set forth in claim 5 or 6, the rotation speed detecting means for detecting the rotation speed of the permanent magnet motor and outputting a voltage signal corresponding to the detected rotation speed, and the rotation speed detection means Adding means for adding the voltage signal output by the torque detection means and the voltage signal output by the torque detection means, or the voltage signal output by the rotation speed detection means and the voltage output by the torque detection means. A signal selecting means for comparing a signal with a signal and selecting and outputting a signal having a higher signal level, wherein the A / D converter is provided by the adding means (claim 5) or the signal selecting means. The voltage signal output by (Claim 6) is A /
It may be configured to perform D conversion. With such a configuration,
The correction value is determined by simultaneously considering both the torque and the rotation speed of the permanent magnet motor, and the energization phase can be corrected.

In this case, the torque detecting means may be a current detecting means for detecting a current of a DC power supply supplied to the driving means as a driving power supply. And a current value processing unit that outputs a voltage signal by performing a sampling process on the current value detected by the current value detection unit.
The current value detected by the current detecting means is averaged (claim 8), sampled and held (claim 9), and peak-held (claim 1).
0).

That is, the current value of the DC power supply is proportional to the load torque of the permanent magnet motor. Further, such a DC power supply is usually generated by rectifying an AC power supply, so that the detection level of the current value always fluctuates. Therefore, the detection signal of the current value is averaged by a smoothing circuit or the like (claim 8), sampled and held by a sample and hold circuit (claim 9), or peaked by a peak hold circuit. Hold processing (claim 10)
Thus, the detection level of the DC power supply current can be appropriately sampled, A / D converted, and output to the phase correction means.

In the above, as described in claim 11, the voltage signal forming means is connected in series at a predetermined ratio, a plurality of resistors for dividing a predetermined voltage, and a count value of the phase estimating means. A selection circuit that outputs a predetermined voltage signal by selecting a connection point of the plurality of resistors may be configured.

According to this structure, the selection circuit of the voltage signal selection means selects a connection point of a plurality of resistors connected in series according to the count value of the phase estimation means and outputs a predetermined voltage signal. I do. That is, at each connection point of the plurality of resistors, a divided potential according to the ratio of the respective resistance values is obtained.
Therefore, if the connection point of the resistor is selected based on the detailed phase of the rotor obtained by the phase estimating means, a smooth voltage signal waveform can be obtained.

According to a twelfth aspect of the present invention, a rotation speed detecting means for detecting the rotation speed of the permanent magnet motor and outputting a voltage signal corresponding to the detected rotation speed, and setting the rotation speed of the permanent magnet motor. Phase control means for outputting a phase command corresponding to the difference between the voltage command given for performing the operation and the voltage signal output by the rotation speed detecting means, and the phase command output by the phase control means for A / D conversion. A / to convert
D / A conversion means may be provided, and the phase correction means may be configured to use the digital data output by the A / D conversion means as a correction value.

With this configuration, the phase correction means uses the digital data obtained by A / D conversion of the phase command output from the phase control means as a correction value. The correction is performed so that the difference from the voltage signal is reduced as much as possible.

In this case, as described in claim 13,
It is preferable to include a speed control unit that outputs a voltage command in accordance with a difference between a speed command externally provided and a voltage signal output by the rotation speed detection unit. With such a configuration, the speed control unit is configured to perform the operation according to a difference between the speed command given from the outside and the voltage signal output from the rotation speed detection unit as a result of driving the permanent magnet motor in accordance with the speed command. Since the voltage command is set, the difference between the two is reflected in the correction value, so that the rotational speed of the permanent magnet motor can be controlled to match the speed command given from the outside as much as possible.

In addition, in the above, as described in claim 14, the phase correction means is configured to set the correction value larger as the digital data output by the A / D conversion means is larger. good. That is, the phase of the current supplied to the windings of the permanent magnet motor is delayed as the rotational speed increases or the load torque increases. Accordingly, by increasing the initial value (correction value) set in the counter of the phase estimating means as the digital data reflecting the increase in the rotation speed and the load torque becomes larger,
Correction can be performed so that the energization signal has a leading phase.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. In FIG. 1 showing an electrical configuration, a DC power supply 1 is generated by performing full-wave rectification on a commercial AC power supply using a diode bridge or the like, and smoothing it using a smoothing capacitor (neither is shown). Both positive and negative terminals of the DC power supply 1 are connected to the DC bus 2a,
It is connected to a power input terminal of the inverter main circuit (drive means) 3 via 2b.

The inverter main circuit 3 is constituted by connecting three transistors 4U, 4V, 4W and 4X, 4Y, 4Z in a three-phase bridge, and a flywheel diode is provided between the collector and the emitter of each transistor 4. 5U,
5V, 5W and 5X, 5Y, 5Z are connected. The output terminals 3U, 3V, 3W of the inverter main circuit 3 are connected to respective phase stator windings (hereinafter simply referred to as windings) 6U, 6V of which one end is star-connected in a permanent magnet motor 6 such as a brushless motor. , 6W are respectively connected to the other terminals.

Further, the permanent magnet motor 6 has a rotor 6R which is arranged so as to have a predetermined gap with the windings 6U, 6V, 6W and is constituted by permanent magnets. Inside the permanent magnet motor 6, a position detector (position signal output means) 7 (7U, 7V, 7W) composed of a Hall IC is arranged to detect the rotational position of the rotor 6R. I have. Then, the position detector 7 (7U, 7V, 7
W), the position signals Hu, Hv, Hw are:
Period measurement circuit (period measurement means) 8, phase correction circuit (phase correction means) 9, and rotation number detection circuit (rotation number detection means) 1
0 is given.

As shown in FIG. 2, the position signals Hu, Hv, Hw are such that the positive half-wave periods of the induced voltages Eu, Ev, Ew generated in the phase windings 6U, 6V, 6W are high level and the negative half-wave period. For a signal whose period is low level, for example, an electrical angle of 3
Position detectors 7U, 7V, 7W are arranged so as to be output as signals having a phase delay of 0 °.

The period measuring circuit 8 generates position signals Hu, Hv,
A rising edge or a falling edge, which is a timing at which any signal level of Hw changes, is detected, and an output interval between them, that is, a time corresponding to a change period T (see FIG. 3B) is countered (not shown). Count by And
The count value is output to the pulse generation circuit (pulse generation means) 11 as period data TD.
The counting cycle of the counter is set to be sufficiently shorter than the changing cycle T. The change period T corresponds to an electrical angle of 60 °.

The pulse generation circuit 11 is, for example, a digital P
It is configured as a frequency multiplier circuit to which the LL circuit is applied. For example, if a frequency corresponding to a change period T of the position signals Hu to Hw is f, a frequency 32f (cycle T / 32) obtained by multiplying the frequency f by 32 is used. A clock pulse CK is generated and output (see FIG. 3C).

More specifically, for example, when the period data TD provided by the period measuring circuit 8 is latched and shifted right by 5 bits to obtain the period data TD / 32, the period data TD / 32 is obtained.
Is counted down at the same count cycle as the counter of the cycle measuring circuit 8. Then, when the count value becomes 0, a clock pulse is generated and output to the phase estimating circuit (phase estimating means) 12, and at the same time, the next given period data TD is latched and shifted, Set to counter. By repeating the above processing, a clock pulse CK having a frequency of 32f is generated and output.

The phase estimating circuit 12 outputs, for example, the position signal Hu
The number of inputs of the clock pulse CK is counted by a counter with the rising edge of the clock as a reference (count value “0”), and the detailed rotation position (phase) of the rotor 6R of the permanent magnet motor 6 is estimated based on the count value CNT. . That is, the count value “1” is an electrical angle of 60 ° / 32 = 1.8.
This would correspond to 75 °. Therefore, the phase estimation circuit 1
2 is an electrical angle of 360 ° when “192” is counted.
(See FIG. 3D), the rising edge of the position signal Hu in the next cycle is given. The count value CNT counted by the phase estimating circuit 12 is provided to a voltage signal forming circuit (voltage signal forming means) 13.

The voltage signal forming circuit 13 comprises, for example, a ROM and a D / A conversion circuit, and stores the waveform data of the voltage signal VSIN having a sine wave amplitude rate as shown in FIG. Have been. Note that an offset is added so that the negative maximum value of the AC amplitude of the voltage signal VSIN becomes data "0". The count value CNT given from the phase estimating circuit 12 is given as a read address of the waveform data of the voltage signal VSIN, and the rotator 6R
The waveform data corresponding to the rotational position of is read.

Further, a voltage command (not shown) is externally applied to the voltage signal forming circuit 13, and the waveform data value of the read voltage signal VSIN includes:
The coefficient according to the voltage command is multiplied. An analog voltage signal obtained by D / A converting the waveform data value is used as a driving signal forming circuit (driving signal forming means) 1.
4 is output. Further, the voltage signal forming circuit 13 reads out the waveform data value of the voltage signal VSIN corresponding to the U phase with reference to the position signal Hu, for example.
The waveform data values corresponding to the 120 ° and 240 ° delayed phases are defined as the waveform data values corresponding to the V phase and the W phase based on the waveform data values. Then, each of them is D / A converted and output to the drive signal forming circuit 14.

Triangular wave generating circuit (carrier wave generating means) 15
Generates a triangular wave VTR which is a carrier wave of the PWM signal and outputs it to the drive signal forming circuit 14, as shown in FIG. 3 (e). The drive signal forming circuit 14 is composed of a comparator or the like, and controls the level of the voltage signal VSIN supplied from the voltage signal forming circuit 13 and the triangular wave VTR.
And outputs the PWM signals Su, Sv, Sw which become high level when the former level is higher (see FIG. 3 (f)). The PWM signal is transmitted to the transistors 4U, 4V, 4W of the inverter main circuit 3 via a base drive circuit (not shown) composed of a photocoupler or the like.
Is provided as a base signal. The transistors 4X, 4Y, and 4Z receive the inverted base signal as the base signal.

On the other hand, the rotation speed detecting circuit 10 outputs the position signal H
For any one of u to Hw, for example, the number of rising edge outputs per second is counted as the number of revolutions of the permanent magnet motor 6, and a voltage signal Vf of a level corresponding to the number of revolutions is added to an adding circuit (adding means). 18 to F /
V conversion is performed. Here, as shown in FIG. 4, it is assumed that the permanent magnet motor 6 is operated in the range of the rotation speed of 0 to 60 Hz, and the range of the output voltage Vf is, for example, 0 to 2.5 V in accordance with the rotation speed range. Is set to output linearly. When the rotation speed exceeds 60 Hz, the voltage Vf is output at a constant 2.5 V.

A current sensor (current detecting means, torque detecting means) 16 such as a current transformer is inserted in the DC bus 2b, and a detection signal of the current sensor 16 is supplied to a peak hold circuit 17. ing. The DC power supply current detected by the current sensor 16 is a current (DC link current) obtained by rectifying and smoothing the AC power supply.
The level of L fluctuates at the AC power supply frequency as shown in FIG. The peak hold circuit (current value processing means, torque detection means) 17 is a well-known circuit composed of a capacitor, an operational amplifier, and the like, and holds the peak level Vp of the detection signal of the current sensor 16 and outputs it to the addition circuit 18. It has become.

Here, as shown in FIG. 6, it is assumed that the permanent magnet motor 6 is operated in a load torque range of 0 to 1 N · m, and the range of the output voltage VT is, for example, 0 in accordance with the load torque range. It is set so that it is output linearly at ~ 2.5V. When the load torque exceeds 1 Nm, VT is output at a constant value of 2.5 V.

The adder circuit 18 is composed of an operational amplifier, a resistor, and the like. The adder circuit 18 analogously adds the voltage signal levels output from the rotation speed detection circuit 10 and the peak hold circuit 17 to form an A / D conversion circuit ( A / D conversion means) 1
9 is output. A / D conversion circuit 19
Converts the analog voltage signal supplied from the adder circuit 18 into A
/ D conversion, and outputs digital data to the phase correction circuit 9. Here, as shown in FIG.
The D conversion circuit 19 converts the voltage range of the input signal from 0 to 5 V with 5 bits and outputs digital data of “0” to “32”.

The phase correction circuit 9 loads the digital data output from the A / D conversion circuit 19 into the counter of the phase estimation circuit 12 as a phase correction value PC, triggered by the rising edge of the position signal Hu. I have. That is, the counter of the phase estimating circuit 12 is such that the count value originally becomes “0” at the rise of the position signal Hu,
The data loaded by the phase correction circuit 9 is set as an initial value (see FIG. 3D).

Next, the operation of this embodiment will be described with reference to FIG. When a start command signal is output from the outside, a start signal generating circuit (not shown) connected to the drive signal forming circuit 14 outputs a 120 ° conduction signal for a certain period of time to rotate the permanent magnet motor 6. Then, the winding 6
U, 6V, and 6W generate an induced voltage, and the position detectors 7U,
7V and 7W detect the change in the magnetic field generated in the rotor 6R due to the generation of the induced voltage, and detect the position signals Hu and H.
v and Hw are output.

The period measuring circuit 8 generates position signals Hu, Hv,
The rising and falling edges of Hw are detected, the time corresponding to the change period T (see FIG. 3B) is counted, and the period data TD, which is the count value, is output to the pulse generation circuit 1.
Output to 1. The pulse generation circuit 11 outputs the position signals Hu to
A clock pulse CK having a frequency 32f, which is 32 times the frequency f corresponding to the change period T of Hw, is output to the phase estimating circuit 12 (see FIG. 3C).
Counts the number of input clock pulses CK with reference to the rising edge of the position signal Hu.

At this time, the phase correction circuit 9 is loaded with the phase correction value PC as an initial value from the phase correction circuit 9. As described above, the phase correction value PC is obtained by A / D conversion of the sum of the detection signal levels of the rotation speed of the permanent magnet motor 6 and the load torque. When the rotation speed of the permanent magnet motor 6 increases, the output voltage Vf of the rotation speed detection circuit 10 increases. When the load torque of the permanent magnet motor 6 increases, the output voltage Vp of the peak hold circuit 17 increases.
Rises. Accordingly, the phase correction value PC increases as either the rotation speed or the load torque increases, and is corrected so that the energization phase (commutation timing) to the permanent magnet motor 6 becomes the leading side.

That is, the windings 6U, 6 of the permanent magnet motor 6
V and 6W have a time constant determined by the resistance and the inductance, and the current flowing through these windings 6U, 6V and 6W is delayed from the applied voltage by a time corresponding to the time constant. Since this delay time is constant irrespective of the rotation speed of the permanent magnet motor 6, the phase delay of the current increases as the rotation speed increases. In addition, since the torque of the permanent magnet motor 6 is generated by multiplying the induced voltage by the winding current, if a phase delay occurs in the winding current, the torque decreases and the efficiency decreases. In the worst case, May lose synchronism.

Based on the above, the phase correction value PC is set and output so that the energization phase to the permanent magnet motor 6 becomes the leading side in accordance with the increase in either the rotation speed or the load torque.

The count value CNT counted by the phase estimating circuit 12 is given to the voltage signal forming circuit 13,
The voltage signal forming circuit 13 reads the waveform data of the voltage signal VSIN according to the count value CNT, performs D / A conversion, and outputs the converted data to the drive signal forming circuit 14. The drive signal forming circuit 14 compares the level of the voltage signal VSIN with the level of the triangular wave VTR to compare the PWM signals Su, Sv, Sw.
(See FIGS. 3E and 3F).

Then, the output terminal 3 of the inverter main circuit 3
8B, drive voltages Vu, Vv, V of a PWM waveform based on the amplitude rate of a sine wave are provided to U, 3V, and 3W.
When w occurs, the permanent magnet motor 6 rotates. At this time, a sinusoidal conduction current flows through each of the phase windings 6U, 6V, and 6W.

As described above, according to the present embodiment, the pulse generation circuit 11 outputs three pulses within the change period T of the position signals Hu to Hw.
Two clock pulses CK are generated, and the phase estimation circuit 12
Calculates the number of clock pulses CK with reference to the rising edge of the position signal Hu,
Of the rotor 6R is estimated. Then, the voltage signal forming circuit 13 reads out the predetermined voltage signal VSIN corresponding to the phase of the rotor 6R from the memory and forms it.

That is, the phase of the rotor 6R is changed to the position signal Hu.
To Hw, the voltage signal forming circuit 13 can obtain a voltage signal V having a sine wave amplitude rate in accordance with the detailed phase of the rotor 6R.
SIN is formed, and the drive signal forming circuit 14 can output a conduction signal waveform (PWM signal) based on the voltage signal VSIN. By applying a sinusoidal current to each phase winding 6U, 6V, 6W of the permanent magnet motor 6, it is possible to minimize the occurrence of vibration, noise, and the like.

At the rising edge of the position signal Hu, the phase correction circuit 9 corrects the phase by setting the phase correction value PC in the counter of the phase estimating circuit 12, and converts the phase correction value PC to a permanent magnet motor. The A / D converted value of the added value of the voltage signal level corresponding to the rotation speed and the voltage signal level corresponding to the load torque of No. 6 was used. Therefore, the phase shift that fluctuates according to the rotation speed and the load torque of the permanent magnet motor 6 is corrected, and each phase winding 6U-
By energizing 6 W, the permanent magnet motor 6 can be operated with high efficiency. Since there is no need to perform complicated calculations using a microcomputer or use a storage device for storing data, the configuration is simplified and the correction process can be performed in a short time.

Further, the phase correction circuit 9 sets the phase correction value PC to increase as either the rotation speed or the load torque of the permanent magnet motor 6 increases, so that the phase correction circuit 9 responds to the increase in the rotation speed or the load torque. The operating efficiency of the permanent magnet motor 6 can be increased by correcting the phase of the current flowing through the permanent magnet motor 6 that causes a delay to the leading side.

Further, according to the present embodiment, the current of the DC power supply 1 is detected by the current sensor 16, and the peak level of the detection signal is held by the peak hold circuit 17. Accordingly, the detection level of the fluctuating DC power supply current is appropriately sampled, A / D converted, and output to the phase correction circuit 12, so that the load torque of the permanent magnet motor 6 is appropriately reflected in the phase correction value PC. be able to.

FIGS. 9 and 10 show a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, only different parts will be described. As shown in FIG. 9, the electrical configuration of the second embodiment differs from the configuration of the first embodiment in that the adder circuit 18, the current sensor 16 and the peak hold circuit 17 are eliminated, and the speed control circuit (speed control means) 20 and Phase control circuit (phase control means) 21
Is added.

That is, a speed command of the permanent magnet motor 6 is externally given as a voltage signal to one input terminal of the speed control circuit 20, and the other input terminal is supplied with a rotational speed detection circuit 10 by the rotation speed detection circuit 10. / V converted voltage signal Vf
Is given. Then, the speed control circuit 20 generates a voltage command according to the difference between the speed command and the voltage signal Vf from the rotation speed detection circuit 10 so that they match, and generates a voltage signal forming circuit 13 and a phase control circuit 21. Output.

The phase control circuit 21 has another input terminal, to which a voltage signal Vf from the rotation speed detection circuit 10 is applied. And
The phase control circuit 21 differentially amplifies the difference between the voltage command from the speed control circuit 20 and the voltage signal Vf from the rotation speed detection circuit 10 to generate a phase command, and outputs the phase command to the A / D conversion circuit 19. It has become. Other configurations are the same as in the first embodiment.

Next, the operation of the second embodiment will be described with reference to FIG. FIG. 10 shows the relationship between the voltage signal Vf output by the rotation speed detection circuit 10 and the voltage command output by the speed control circuit 20 when the permanent magnet motor 6 is operated with no load. As shown in FIG. 10, at the time of no load, the F / V conversion rate in the rotation speed detection circuit 10 is adjusted so that the voltage signal Vf and the voltage command have the same voltage.

In the case of controlling at a constant rotation speed (speed), when a load is applied to the permanent magnet motor 6, the speed control circuit 20 increases the voltage command value in order to keep the speed constant. Then, in the phase control circuit 21, the difference between the voltage command and the voltage signal Vf from the rotation speed detection circuit 10 increases, and the phase command value output from the phase control circuit 21 also increases according to the difference. The A / D conversion circuit 19 outputs the data obtained by A / D conversion of the phase command value to the phase correction circuit 12, so that the commutation timing is advanced as the load torque of the permanent magnet motor 6 increases. Correction is performed.

As described above, according to the second embodiment, the speed control circuit 20 controls the rotation speed detection circuit 10 as a result of the externally applied speed command and the fact that the permanent magnet motor 6 is driven according to the speed command. A voltage command is set according to the difference between the voltage command and the voltage signal Vf output from the motor. The phase control circuit 21 differentially amplifies the difference between the voltage command and the voltage signal Vf from the rotation speed detection circuit 10 to obtain a phase command. Generate. Then, the phase correction circuit 12 sets the digital data obtained by A / D conversion of the phase command as a phase correction value PC.

Therefore, the commutation timing can be corrected so as to advance as the load torque of the permanent magnet motor 6 increases. Further, it is possible to control the rotation speed of the permanent magnet motor 6 to match the speed command given from the outside as much as possible.

FIG. 11 shows a third embodiment of the present invention, and shows an electrical configuration of a main part. In the third embodiment, a voltage signal forming circuit (voltage signal forming means) 22 instead of the voltage signal forming circuit 13 is provided. The voltage signal forming circuit 22 includes, for example, a series resistance circuit 23 in which n resistors 23R are connected in series, and a selection circuit 24.

One end P0 of the series resistance circuit 23 is connected to the ground, and the other end Pn is supplied with an external voltage command. Then, the connection point P0 of each resistor 23R.
Pn is connected to the input terminal of the selection circuit 24. The selection circuit 24 outputs a voltage signal VSIN to the drive signal forming circuit 14 by selecting any one of the connection points P0 to Pn according to the count value CNT given from the phase estimation circuit 12. .

The resistance values of the respective resistors 23R are not the same, and the selection circuit 24 determines the connection point P0 according to the count value CNT.
To Pn are selected to output the voltage signal VSIN. Further, as in the first embodiment, when the count value CNT is “192” and the electrical angle is 36
When the angle is 0 °, the connection number n of the resistor 23R is set to, for example, n
= 192/2 = 96. Although not specifically shown, the series resistance circuit 23 is actually provided for each phase, and the selection circuit 24 provides the count value CNT.
, The connection points P0 to Pn are selected for each phase.

According to the third embodiment configured as described above, the selection circuit 24 controls the connection point P according to the count value CNT.
By selecting any one of 0 to Pn, a voltage signal VSIN having a signal level corresponding to the amplitude ratio of the sine wave can be output. In this case, the maximum amplitude level of the voltage signal VSIN is directly set by the voltage command. Therefore, the permanent magnet motor 6 can be driven with low vibration and low noise as in the first or second embodiment. Further, the voltage signal forming circuit 22 includes a ROM and a D / A
The configuration can be performed at lower cost without using a conversion circuit.

The present invention is not limited to the embodiment described above and shown in the drawings, and the following modifications or extensions are possible. In the first embodiment, the cycle measuring circuit 8 measures the cycle in which any one of the position signals Hu to Hw changes, but may measure the cycle of any one of the position signals. Then, the position detectors 7U to 7W may be provided for only one phase. The pulse generating means is
The change period is not limited to 32 times, but may be any number as long as it is an integer of 2 or more. Further, if the phase estimating means obtains the generation timing information of each pulse in advance, the configuration is not limited to multiplying the change period by a plurality of times. For example, a plurality of pulses are generated within one change period. Is also good.
The output signal of the peak hold circuit 17 and the output signal of the rotation speed detection circuit 10 are A / D-converted by separate A / D converters, and digital data output by each A / D converter is added. May be output to the phase correction circuit 12. In addition, instead of adding the output signals of both, the addition circuit 18 may be provided with a signal selection means for selectively outputting the signal having the higher signal level to the A / D conversion circuit 19. In that case, the voltage range on the vertical axis shown in FIGS. 4 and 6 may be set to 0-5V.

In the first embodiment, the rotation speed detection circuit 10 and the addition circuit 18 may be omitted, and only the current sensor 16 and the peak hold circuit 17 may be provided. Alternatively, the addition circuit 18 and the current sensor 16 and the peak hold circuit 17 may be deleted and only the rotation speed detection circuit 10 may be provided. Instead of the peak hold circuit 17, as the current value processing means, the detection voltage level output from the current sensor 16 may be averaged by an integrating circuit, or a sample and hold circuit for sampling and holding at a predetermined timing may be arranged. Is also good. The voltage signal waveform formed by the voltage signal forming means is not limited to a waveform based on a sine wave.
The waveform may be as shown in FIG. In the case of such a waveform, the terminal voltage waveform of the permanent magnet motor 6 is 0 V for substantially half a cycle. 120 ° even with such a waveform
It is possible to reduce the vibration and noise of the permanent magnet motor as compared with the energization signal. Further, the maximum output voltage of the inverter main circuit 3 can be increased.

The carrier generation means is not limited to a triangular wave, but may be a means for generating a sawtooth wave as a carrier wave.
In the second embodiment, the speed control circuit 20 may be deleted, and the speed command may be directly provided as a voltage signal to be applied to the phase control circuit 21. The position signal output means includes a position detector 7
Not only U, 7V and 7W, but also those which output a position signal by detecting a zero cross point (polarity change point) of an induced voltage waveform generated in the windings 6U to 6V using a voltage dividing resistor, a comparator, or the like. good. The voltage signal forming circuit 13 includes U,
A ROM is provided for each of the V and W phases, and the same address of the counter output from the phase estimating circuit 12 is delayed by 120 ° from the V-phase ROM to the U-phase ROM. So that the waveform data value of
From the W-phase compliant ROM to the U-phase compliant ROM, 24
Data may be stored such that a waveform data value delayed by 0 ° is read.

[0064]

According to the inverter device of the present invention, the pulse generating means has a constant value with respect to the induced voltage generated in the plural-phase stator windings in accordance with the rotational position of the rotor constituting the permanent magnet motor. A plurality of pulses are generated within a change period of the position signal having a phase relationship, and the phase estimating means counts the number of clock pulses generated by the pulse generating means by a counter. Then, the phase of the rotor is estimated based on the count value of the counter based on the timing at which the position signal changes, and the voltage signal forming means forms a predetermined voltage signal according to the phase of the rotor.

That is, since the phase of the rotor can be obtained with a more detailed resolution than the change period of the position signal, the voltage signal generating means generates the permanent magnet motor in accordance with the detailed phase of the rotor. It is possible to form a voltage signal capable of suppressing vibration, noise, and the like more than a 120 ° conduction signal. Then, an energizing signal waveform based on the voltage signal is applied to the stator winding by the driving means, so that the permanent magnet motor can be driven with low vibration and low noise. Further, the phase correction means corrects the phase of the rotor by setting a correction value to the counter at the reference timing of the position signal, so that the microcomputer performs a complicated calculation or stores data using the microcomputer. The phase is corrected without using a storage device, and the stator winding is energized with an appropriate phase, so that the permanent magnet motor can be operated with high efficiency.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing an electric configuration according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between an induced voltage generated in a stator winding of a permanent magnet motor and a position signal.

FIG. 3 is a timing chart of each signal.

FIG. 4 is a diagram showing a frequency (rotation speed of a permanent magnet motor) -voltage conversion characteristic in a rotation speed detection circuit.

FIG. 5 is a waveform diagram of a DC power supply current detected by a current sensor.

FIG. 6 is a diagram showing a relationship between a hold level in a peak hold circuit and a load torque of a permanent magnet motor.

FIG. 7 is a diagram showing A / D conversion characteristics in an A / D conversion circuit;

FIG. 8A shows a voltage signal VSIN and a carrier signal VT.
R and (b) show the terminal voltage of each phase of the permanent magnet motor, and (c) shows the U-V phase voltage waveform.

FIG. 9 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 10 shows a relationship between an F / V conversion voltage signal output by a rotation speed detection circuit and a voltage command output by a speed control circuit during a no-load operation.

FIG. 11 is an electrical configuration diagram of a main part showing a third embodiment of the present invention.

FIG. 12 is a diagram corresponding to FIG. 8 showing a modification.

[Explanation of symbols]

1 is a DC power supply, 3 is an inverter main circuit (drive means), 6
Is a permanent magnet motor, 6U, 6V, 6W are stator windings, 6
R is a rotor, 7U, 7V and 7W are position detectors (position signal output means), 8 is a cycle measurement circuit (cycle measurement means), 9 is a phase correction circuit (phase correction means), and 10 is a rotation speed detection circuit ( Rotational speed detecting means), 11 is a pulse generating circuit (pulse generating means), 12 is a phase estimating circuit (phase estimating means), 13
Is a voltage signal forming circuit (voltage signal forming means), 14 is a driving signal forming circuit (driving signal forming means), 15 is a triangular wave generating circuit (carrier wave generating means), 16 is a current sensor (current detecting means, torque detecting means), 17 is a peak hold circuit (current value processing means, torque detection means), 18 is an addition circuit (addition means), 19 is an A / D conversion circuit (A / D conversion means), and 20 is a speed control circuit (speed control means). , 21 are a phase control circuit (phase control means), 22 is a voltage signal forming circuit (voltage signal forming means), 23R is a resistor, and 24 is a selection circuit.

Claims (14)

[Claims] 1. A position signal output means for outputting a position signal having a fixed phase relationship with respect to an induced voltage generated in a plurality of stator windings according to a rotational position of a rotor constituting a permanent magnet motor. A cycle measuring means for measuring a change cycle of the position signal; a pulse generating means for generating a plurality of clock pulses within the change cycle; and a counter for counting the number of generated clock pulses. Phase estimating means for estimating a phase of the rotor based on a count value of the counter with reference to a changing timing; and a phase for setting a correction value to the counter and correcting the phase of the rotor at the timing. Correction means; voltage signal forming means for forming a predetermined voltage signal in accordance with the phase of the rotor; carrier wave generating means for outputting a carrier wave of a PWM signal A drive signal forming means for comparing the signal level of the voltage signal with the signal level of the carrier wave to form a drive signal; and driving the plurality of phase stator windings based on the drive signal. And an inverter device. 2. The inverter device according to claim 1, wherein the voltage signal formed by the voltage signal forming means has a sine wave shape. 3. A rotation speed detecting means for detecting the rotation speed of the permanent magnet motor and outputting a voltage signal corresponding to the detected rotation speed;
3. The inverter device according to claim 1, further comprising A / D conversion means for performing D conversion, wherein the phase correction means uses the digital data output by the A / D conversion means as a correction value. 4. A torque detecting means for detecting a torque of a permanent magnet motor and outputting a voltage signal corresponding to the detected torque;
3. The inverter device according to claim 1, further comprising A / D conversion means for performing D conversion, wherein the phase correction means uses the digital data output by the A / D conversion means as a correction value. 5. A rotational speed detecting means for detecting a rotational speed of a permanent magnet motor and outputting a voltage signal corresponding to the detected rotational speed; a voltage signal output by the rotational speed detecting device; 5. An adder for adding the output voltage signal, wherein the A / D converter performs A / D conversion on the voltage signal output by the adder.
The inverter device as described. 6. A rotational speed detecting means for detecting a rotational speed of a permanent magnet motor and outputting a voltage signal corresponding to the detected rotational speed; a voltage signal output by the rotational speed detecting device; Signal selecting means for comparing a voltage signal outputted and selecting a higher signal level for output, wherein the A / D converting means converts the voltage signal outputted by the signal means into an A / D signal. 5. The method according to claim 4, wherein the conversion is performed.
The inverter device as described. 7. A torque detecting means, comprising: a current detecting means for detecting a current of a DC power supply supplied to the driving means as a driving power supply; a torque detecting means for sampling a current value detected by the current detecting means; 7. The inverter device according to claim 4, comprising an output current value processing unit. 8. The inverter device according to claim 7, wherein the current value processing means averages the current value detected by the current detection means. 9. The inverter device according to claim 7, wherein the current value processing means samples and holds the current value detected by the current detection means. 10. The inverter device according to claim 7, wherein the current value processing means performs peak hold processing on the current value detected by the current detection means. 11. The voltage signal forming means is connected in series at a predetermined ratio, and selects a plurality of resistors for dividing a predetermined voltage and a connection point of the plurality of resistors according to a count value of the phase estimating means. And a selection circuit for outputting a predetermined voltage signal.
11. The inverter device according to any one of claims 10 to 10. 12. A rotation speed detecting means for detecting a rotation speed of a permanent magnet motor and outputting a voltage signal corresponding to the detected rotation speed, a voltage command given for setting the rotation speed of the permanent magnet motor, Phase control means for outputting a phase command corresponding to the difference between the voltage signal output from the rotation speed detection means, and an A / D
3. The inverter device according to claim 1, further comprising A / D conversion means for performing conversion, wherein the phase correction means uses the digital data output by the A / D conversion means as a correction value. 13. A speed control means for outputting a voltage command in accordance with a difference between a speed command given from the outside and a voltage signal outputted by a rotation speed detecting means. Inverter device. 14. The apparatus according to claim 3, wherein the phase correction unit sets the correction value to be larger as the digital data output by the A / D conversion unit is larger. Inverter device.