JP2001008489A - Inverter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance performance of a position detecting means. SOLUTION: An inverter circuit 47 supplying three-phase power is fitted to a motor 46. A position detecting means 66 compares the voltage of output terminal 55, 56, 57 with the magnitude of a reference value generating means 67. A drive circuit 65, after a delay time by a delaying means 72 has elapsed since the comparison means 70 outputted, conducts on/off control of high- potential side switching element 59, 60, 61 and low-potential side switching elements 62, 63, 64. The reference value generating means 67 changes the output, in synchronization with it. It is thus possible to ensure the performance of the position detecting means 66 for attaining high reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device for driving a motor, which is used for a washing machine used at home or the like.

[0002]

2. Description of the Related Art A circuit diagram of a conventional inverter device is shown in FIG.
Shown in The inverter device of FIG. 11 includes a motor 1 and an inverter circuit 2 that supplies three-phase power to the motor 1.
The motor 1 has a rotor 5 having permanent magnets 3 and 4 and a stator 9 having three-phase windings 6, 7.8. The inverter circuit 2 has three-phase output terminals 10.11.12 and 280V. DC power supply 13 and high-potential side switching elements 14, 15, 16
And low potential side switching elements 17, 18, 19, a drive circuit 20, and a position detecting means 21.

[0003] High potential side switching element 14.15.1.
6 is a high potential side terminal of the DC power supply 13 and output terminals 10 and 11
12 is connected between the low-potential side switching element 17
18 and 19 are connected between the low-potential side terminal of the DC power supply 13 and the output terminals 10 11 12.

[0004] These switching elements are, for example, IG
A reverse conduction type using a BT and connecting a reverse conduction diode between its collector and emitter is used.

The position detecting means 21 includes comparators 22 and 2
Comparison means 25 and delay means 26 constituted by 3 · 24
And the voltage dividing circuit 27 includes resistors 28, 29, 30
· 31 · 32 · 33, three-phase output terminals 10 · 11 to the minus terminal of the DC power supply 13
-Divides the voltage of 12.

The filter circuit 34 includes resistors 35, 36.3
7. It is composed of capacitors 38, 39, and 40 and functions to remove high-frequency components such as noise contained in the output of the voltage dividing circuit 27.

The synthesizing circuit 41 includes resistors 42, 43, 44,
It is constituted by a capacitor 45 and connected to the output of the voltage dividing circuit 27, and outputs a voltage obtained by combining three-phase terminal voltages to the comparing means 25.

The comparing means 25 comprises comparators 22 and 23
By the operation of 24, the magnitude of the output voltage of the synthesis circuit 41 is compared with the magnitude of the output voltage of the filter circuit 34 to perform a logical output.

The delay means 26 receives the logic signal output from the comparison means 25 and provides a predetermined delay time from the time when the logic changes from high to low, or from low to high, and outputs it to the drive circuit 20. Is what you do.

FIG. 12 shows operation waveforms of various parts of the conventional inverter device under a low torque condition.
(A) is an ON / OFF waveform of the high potential side switching element 14, (A) is an ON / OFF waveform of the low potential side switching element 17, and (C) is a + input terminal voltage V1 of the comparator 22.
And the waveform of the voltage V2 supplied from the combining circuit 41 to the minus input terminal of the comparator 22, and (d) is the voltage waveform of the output voltage V3 of the comparator 22.

V1 shown in (c) is similar to the voltage of the output terminal 10 with respect to the minus terminal of the DC power supply 13, and has a waveform from which high-frequency components such as noise have been removed.

V2 is an output of the synthesizing circuit 41 and has a voltage waveform substantially similar to the voltage at the neutral point a of the three-phase windings 6, 7, 8 of the motor 1.

In FIG. 12, when the high-potential-side switching element 14 is turned off at time t1, the magnetic energy stored in the inductance of the winding 6 immediately lowers the voltage to almost zero volt, and the internal reverse conduction occurs. The diode is turned on.

At time t2, the release of the energy is completed, and V1 changes the windings 6, 7,.
Turning off 8 causes a voltage due to the induced electromotive force to be generated.

Then, V1 decreases as the motor 1 rotates.

On the other hand, V2 is obtained by superimposing a little ripple around a value of about half the voltage of the DC power supply 13, and at time t3, the magnitude relationship between V1 and V2 is switched, and V3 changes from high to low. Become.

Similarly, when the low-potential-side switching element 17 is turned off at time t4, the voltage immediately rises to the output voltage of the DC power supply 13 due to the magnetic energy stored in the inductance of the winding 6, and The reverse conducting diode is turned on.

At time t5, the release of the energy is completed, and V1 changes the windings 6, 7,.
Turning off 8 causes a voltage due to the induced electromotive force to be generated.

Then, V1 rises with the rotation of the motor 1, and at time t6, the magnitude relationship between V1 and V2 is switched, and V3 changes from low to high.

When V3 is input to the delay means 26, t3
At timings t7 and t8, which are delayed by the delay time td from the timings of t6 and t6, a signal is sent to the drive circuit 20, and as shown in (a) and (a), the high potential side switching element 14 and the low potential side 17 turn-ons are performed.

Although not shown in FIG. 12, at the same time as the turn-on, the switching elements of the other phases which are in the on-state immediately before are turned off.

Here, td is a period of about 30 degrees in electrical angle, and the delay means 26 is realized by a digital delay circuit called a timer counter when constituted by, for example, a microcomputer. Will be.

Signal changes occurring at the timings t1, t2, t4, and t5 are ignored by software processing of the microcomputer and the like.

The above operation has been described for only one of the three phases. The same applies to the remaining two phases, and an operation called 120-degree energization is performed.
Is rotated.

FIG. 13 shows operation waveforms when the load is heavy and the current value supplied from the inverter circuit 2 to the motor 1 is large. FIGS. The waveform is shown.

In FIG. 13, since the current stored in the winding 6 is large because the current is large, the high-potential side switching element 14 is turned off at t1.
It takes a long time until the release of the energy is completed at t2.

Similarly, in the operation after the low-potential side switching element 17 is turned off, similarly, the time between t4 and t5 becomes longer.

The waveform of the induced electromotive force appears after t2 after the high-potential-side switching element 14 is turned off, and after t5 after the low-potential-side switching element 17 is turned off. Since the rotation of the rotor 5 has already progressed,
As shown in (c), the intersection of V1 and V2 during the period in which the induced electromotive force appears does not exist.

Therefore, as shown in (d), the output of the comparator 22 changes only at t1 immediately after the turn-off time of the high-potential switching element 14 and at t4 immediately after the turn-off time of the low-potential switching element 17. , The position of the rotor 5 cannot be detected.

Therefore, in practice, rotation under such a high torque condition cannot be performed.

FIG. 13 shows that the drive circuit 20 is operated by a special method (for example, a separately provided rotation sensor) so that the high potential side switching elements 14, 15, 16 and the low potential side switching elements 17, 18,. 19 is turned on and off.

[0032]

In such a conventional technique, when the load is heavy and the torque and the current are large, the energy stored in the winding becomes large, and the time required for discharging the energy is large. Is large, the input waveform of the comparison means 25 does not intersect during the period when the induced electromotive force appears at the motor terminal, so that the position of the rotor cannot be detected, and there is a problem that the operation cannot be performed.

In particular, when the motor is designed to have a large number of windings, such as a so-called "copper machine",
The inductance of the winding is increased, and the tendency is increased.

Further, in order to control the speed of the motor, either the high-potential side switching element or the low-potential side switching element is chopped, and the voltage of the DC power supply is reduced equivalently by the conduction ratio. In such a case, the terminal voltage waveform during the period of the induced electromotive force changes due to the conduction ratio, and even if the input voltage of the comparison means passes through the filter circuit for removing the carrier frequency component, the input waveform of the comparison means is still different from the output of the synthesis circuit. There were also conditions that were not sufficient to cross.

Further, the value of the induced electromotive force also changes in response to a change in the speed of the motor. For example, under low-speed conditions, the induced electromotive force tends to be small, so that the timing shift tends to be large.

As described above, in the prior art, the conditions under which the position detection operation is possible are limited with respect to the conditions of torque and speed, and the apparatus is operated under the condition that the timing shift is large even within the conditions capable of position detection. In some cases, the efficiency of the motor may be reduced, so that the performance of the motor cannot be sufficiently obtained.

[0037]

In order to solve the above-mentioned problems, the present invention comprises a motor and an inverter circuit for supplying three-phase power to the motor, wherein the motor is provided with a rotor having a permanent magnet and a three-phase motor. The inverter circuit includes a stator having windings, and the inverter circuit includes a three-phase output terminal, a DC power supply, three high-potential-side switching elements, three low-potential-side switching elements, a drive circuit, and position detecting means. The three high-potential-side switching elements are connected to a high-potential-side terminal of the DC power supply.
The three low-potential-side switching elements are connected between the low-potential-side terminal of the DC power supply and the three-phase output terminals, and the position detecting means is compared with the reference value generating means. Means for comparing the voltage of the three-phase output terminal with the magnitude of the reference value generating means, and the drive circuit has passed the delay time of the delay means from the output of the comparing means. Thereafter, on / off control of the three high-potential-side switching elements and the three low-potential-side switching elements is performed, and the reference value generating means changes an output value in synchronization with the on / off control, thereby obtaining a torque reduction. By ensuring a sufficient area where position detection can be performed under speed conditions and minimizing the timing deviation within the area where position detection is possible, the efficiency of the device is improved and the motor has The thing that can be drawn enough.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION
A motor and an inverter circuit for supplying three-phase power to the motor, the motor having a rotor having permanent magnets and a stator having three-phase windings, wherein the inverter circuit has a three-phase output terminal; It has a DC power supply, three high-potential-side switching elements, three low-potential-side switching elements, a drive circuit, and position detecting means, wherein the three high-potential-side switching elements are connected to a high-potential-side terminal of the DC power supply. Connected between the three-phase output terminals, the three low-potential-side switching elements are connected between the low-potential-side terminal of the DC power supply and the three-phase output terminals, and the position detecting means is connected to the reference value generating means. Comparing means for comparing the voltage of the three-phase output terminal with the magnitude of the reference value generating means, and the driving circuit calculates the delay time of the delay means from the output of the comparing means. After passing, On / off control of the three high-potential-side switching elements and the three low-potential-side switching elements is performed, and the reference value generating means changes an output value in synchronization with the on / off control, thereby controlling a load on the motor. Even when the current increases, the comparing means can satisfactorily detect the point of intersection of the output of the reference value generating means and the voltage of the three-phase output terminal, thereby ensuring the performance of the position detecting means. Thus, an inverter device having high reliability can be realized.

According to a second aspect of the present invention, in the inverter device according to the first aspect, the drive circuit includes the three high potential side switching elements and the three low potential side switching elements each having an electrical angle of 120. By turning on each time, and performing on-off control by pulse width modulation during the first half of the 60-degree period, and maintaining the on-state during the second half of the 60-degree period, the load on the motor also increases the current. In this case, the comparison means can satisfactorily detect a point at which the output of the reference value generation means and the voltage of the output terminal of the three phases intersect, and the performance of the position detection means can be ensured. A high reliability and low noise inverter device that realizes a reduction in noise generated from the device by suppressing a temporal change in current supplied to the motor. Those that can be achieved.

According to a third aspect of the present invention, the drive circuit of the inverter device according to the first aspect is configured such that the three high-potential-side switching elements and the three low-potential-side switching elements each have an electrical angle of 120. By turning on each time, and maintaining the on state during the first half of the 60-degree period, and performing on-off control by pulse width modulation during the second half of the 60-degree period, the current increases due to the load on the motor. In this case, the comparison means can satisfactorily detect a point where the output of the reference value generation means and the voltage of the output terminal of the three phases intersect, and the performance of the position detection means can be ensured. By increasing the temporal change of the current supplied to the motor, it is possible to realize an inverter device with further improved position detection characteristics. That.

According to a fourth aspect of the present invention, the drive circuit of the inverter device according to any one of the first to third aspects of the present invention,
On / off control of at least one of the high-potential side switching elements and the three low-potential side switching elements is performed by pulse width modulation, and the reference value generation means outputs an output value in accordance with the duty ratio of the pulse width modulation. Even when the current increases due to the load applied to the motor, the comparing means can satisfactorily determine the point at which the output of the reference value generating means intersects with the voltage of the three-phase output terminal. This makes it possible to realize a highly reliable inverter device that can eliminate the influence of the characteristics of the position detecting means due to the value of the pulse width modulation.

According to a fifth aspect of the present invention, there is provided a current detecting means for detecting a current in the inverter device according to the first to third aspects, wherein the reference value generating means responds to an output of the current detecting means. Thus, even when the current increases due to the load applied to the motor, the comparing means intersects the output of the reference value generating means with the voltage of the three-phase output terminal. Points can be detected satisfactorily, the performance of the position detection means can be ensured, and an inverter device with excellent position detection characteristics, especially for motors with high impedance such as copper machines, is realized. Is what you can do.

According to a sixth aspect of the present invention, in the inverter device according to the first to third aspects, the reference value generating means includes:
With the configuration in which the output value is changed according to the speed of the motor, even when the current increases due to the load applied to the motor, the comparing means outputs the reference value generating means output and the three-phase output terminal. It is possible to satisfactorily detect a point at which the voltage intersects the voltage, and to realize an inverter device capable of ensuring the performance of the position detecting means even at a wide range of speeds.

According to a seventh aspect of the present invention, there is provided a current detecting means for detecting a current inside the inverter device according to any one of the first to third aspects, and the reference value generating means detects at least the output value of the current value by the current detecting means. With the configuration as a function of the two inputs of the output value of the means and the speed of the motor, even when the current increases due to the load on the motor, the comparing means can output the reference value generating means and the output of the reference value generating means. It is possible to satisfactorily detect the point of intersection with the voltage of the output terminal of the phase, to ensure the performance of the position detection means, and to ensure the performance of the position detection means even over a wide range of speeds. It is possible to realize an inverter device capable of performing the above.

The invention according to claim 8 has current detecting means for detecting a current inside the inverter device according to any one of claims 1 to 7, wherein the delay means responds to an output of the current detecting means. With the configuration in which the delay time is changed, even when the current increases due to the load on the motor, a correction corresponding to the amount of advance of the phase is performed, so that an inverter device having excellent position detection characteristics is provided. It can be realized.

According to a ninth aspect of the present invention, the delay device of the inverter device according to the first to sixth aspects is configured to change a delay time according to the speed of the motor, so that a wide range of speeds can be obtained. In this case, since the correction corresponding to the amount of advance of the phase or the advance time is always performed, an inverter device having excellent position detection characteristics can be realized.

The tenth aspect of the present invention is the first aspect of the present invention.
8. A current detecting means for detecting a current inside the inverter device according to claim 7, wherein the delay means sets a delay time to at least an output value of the current detecting means and a speed of the motor.
With the configuration as a function of the input, even when the current increases due to the load applied to the motor, the correction corresponding to the amount of phase advance is applied, and the phase advance amount or the advance time is always obtained over a wide range of speeds. Thus, an inverter device having excellent position detection characteristics can be realized.

[0048]

Next, specific examples of the present invention will be described.

(Embodiment 1) FIG. 1 is a circuit diagram of a converter circuit according to one embodiment of the present invention. The inverter device of FIG.
6 and an inverter circuit 47 for supplying three-phase power to the motor 46. The motor 46 has a rotor 50 having permanent magnets 48, 49 and a stator 54 having three-phase windings 51, 52, 53. The inverter circuit 47 has three-phase output terminals 55, 56, 57, a 280V DC power supply 58, high-potential-side switching elements 59, 60, 61, low-potential-side switching elements 62, 63, 64, a drive circuit 65, and position detection. Means 66 are provided.

In this embodiment, the high-potential-side switching elements 59, 60 and 61 and the low-potential-side switching element 6
Each of 2.63.64 uses an insulated gate bipolar transistor IGBT and a diode for reverse conduction connected between its collector and emitter.

Here, the high potential side switching element 59
60 and 61 are connected between the high potential side terminal of the DC power supply 58 and the three-phase output terminals 55, 56 and 57, and the low potential side switching elements 62, 63 and 64 are connected to the low potential side terminal of the DC power supply 58 and the three phase output terminals. Are connected between the output terminals 55, 56 and 57.

The position detecting means 66 includes a reference value generating means 67, a voltage dividing circuit 68, a filter circuit 69, and a comparing means 7.
0, an unnecessary pulse removing circuit 71 and a delay means 72.

The voltage dividing circuit 68 includes resistors 73, 74, 75,
76, 77, 78, and a filter circuit 69
Are resistors 79, 80, 81 and capacitors 82, 83.8
4 and the comparing means 70 comprises a comparator 85
86 and 87.

In this embodiment, the reference value generating means 67 is composed of a resistor 88 and a capacitor 89, and converts the signal Ss pulse-modulated at a carrier frequency of 250 kHz from the drive circuit 65 into a DC voltage substantially free from ripples. Is output to the comparison means 70 as a reference value.

Thus, the comparing means 70 compares the voltages of the three-phase output terminals 55, 56 and 57 with the magnitude of the reference value generating means 67, and the driving circuit 65 calculates the delay time of the delay means 69 from the output of the comparing means 68. After that, the on / off control of the three high-potential side switching elements 59, 60, 61 and the three low-potential side switching elements 62, 63, 64 is performed, and the reference value generating means 67 is synchronized with the on / off control. To change the output value.

FIGS. 2A and 2B are operation waveform diagrams of various parts in this embodiment. FIG. 2A shows an ON / OFF control waveform of the high-potential side switching element 59 from the drive circuit 65.
(A) is an ON / OFF control waveform of the low-potential side switching element 62 from the drive circuit 65, (C) is ground, that is, the terminal voltage of the output terminal 55 viewed from the minus output of the DC power supply 58, and (D) is viewed from ground. The voltage waveform of the voltage V1 input to the plus input terminal and the voltage waveform of the voltage V2 input to the negative input terminal of the comparator 85, (E) is the output voltage waveform V3 of the comparator 85, and (F) is the voltage waveform of the unnecessary pulse removing circuit 71. 3 shows an output voltage waveform.

In the first embodiment, since the driving circuit 65 of the second embodiment is used, the driving circuit 65 includes the high-potential side switching elements 59, 60, 61 and the low-potential side switching elements 62, 63, 64. Are turned on by 120 electrical degrees at a time, and on-off control is performed by pulse width modulation during the first 60 degrees, and the on state is maintained during the second 60 degrees. The test is performed at a frequency of 15.6 kHz.

The Ss signal from the drive circuit 65 has an electrical angle of 6
The duty value is changed every 0 degree, and in the present embodiment, the duty ratio is 30% from time t1 to t2 and 70% from time t2 to t3.
(Dashed line).

On the other hand, the voltage waveform of V1 is 15.6 kHz as a result of passing through the filter circuit 69 from the output of the voltage dividing circuit 68.
The voltage waveform has a carrier frequency component of z substantially removed.

At time t3, immediately after the high-potential-side switching element 59 is turned off, and at time t6, immediately after the low-potential-side switching element 62 is turned off, the energy stored in the inductance of the winding 51 and the like. As a result, there is a “diode period” in which a diode built in each switching element is turned on, so that the voltage waveform of V1 once becomes a waveform stuck to a high potential and a low potential (ground potential).

Therefore, as shown in (e), an unnecessary pulse is generated during the period corresponding to the diode period from t3 and t6.

In the present embodiment, the unnecessary pulse removing circuit 71 is provided, and the unnecessary pulse removing circuit 71 detects the V1 signal generated within 20 microseconds from the switching of the switching element performed by the driving circuit 65 every 60 electrical degrees. By ignoring the edge, an operation of removing an unnecessary pulse generated in the diode period is performed.

As a result, the unnecessary pulse is logically removed, and the output has an edge at times t10 and t11 (both at the intersection of V1 and V2) as shown in FIG. In both the high period and the low period, a signal having an electrical angle of 180 degrees can be obtained.

Particularly, in the configuration in which pulse width modulation is performed in the first half of 60 degrees as in the first embodiment, the current in the diode period immediately after switching of the switching element is
Since the current flows through a path almost short-circuiting between the terminals of the motor 46, the absolute value of the temporal change amount (dI / dt) of the current supplied to each winding of the motor 46 is reduced, and the current value is gently reduced. As a result, the effect that the noise generated at the switching timing of the switching element can be reduced can be obtained.

On the other hand, immediately after switching any of the switching elements, the diode period becomes longer and the operation of the comparing means 70 of the position detecting means 66 tends to be hindered. 67 generates the reference value which changes in synchronization with the switching of the switching element.
Can clearly detect the magnitude relationship and ensure good reliability.

In this embodiment, the delay means 72 outputs a signal to the drive circuit 65 after the time td has elapsed from t10 and t11, and the low-potential side switching element 62 and the high-potential side switching element at t4 and t7. 59 is turned on.

As described above, in this embodiment, V2
Has an electrical angle of 6 in synchronization with the on / off control of the switching element.
Since it is changed every 0 degrees, there is a clear intersection between V1 and V2, malfunction does not occur even with some noise or the like, and it is extremely reliable and operates satisfactorily.

In this embodiment, the V2 signal has a high duty during the ON period of the low-potential-side switching element, and a low duty corresponds to the ON period of the high-potential-side switching element. Therefore, there is also an effect that generation of the Ss signal from the drive circuit 65 can be realized relatively easily.

In the case where the high-potential side switching element and the low-potential side switching element are alternately pulse-width modulated as in the first embodiment, the combining circuit 41 of the prior art shown in FIG. Although a waveform that changes every 60 electrical degrees as shown by V2 in FIG. 2D can be naturally obtained, the amount of the change cannot be adjusted, and therefore, especially with a copper machine. In the case of a so-called motor having a large impedance, there is a condition that the intersection of V1 and V2 does not occur, or that there is not enough noise margin even if the intersection exists.

Therefore, the reference value generating means 6 of the first embodiment
By using the configuration of FIG. 7, it is possible to freely set a value that fluctuates V2 every electrical angle of 60 degrees, thereby obtaining the intersection of V1 and V2 even with a copper machine, It is possible to realize a reliable device having a margin due to the influence of the above.

(Embodiment 2) FIG. 3 shows an operation waveform diagram of an embodiment 2 using the third aspect.

In the second embodiment, the circuit configuration is almost the same as that of FIG.
Is the same as that of the first embodiment shown in FIG.
Turns on the high-potential-side switching elements 59, 60, 61 and the low-potential-side switching elements 62, 63, 64, each at an electrical angle of 120 degrees, and keeps the ON state during the first half of the 60-degree period; The only difference from the first embodiment is that the on / off control is performed by pulse width modulation during the period of.

Also in this case, although the duty value of the Ss signal from the drive circuit 65 is slightly different from that of the first embodiment,
Again, V2 has a voltage waveform that alternates between high and low every electrical angle of 60 degrees, and a clear intersection timing can be obtained at times t10 and t11.

In this embodiment, the diode period that occurs every 60 degrees immediately after the switching of the switching element is short, so that the first embodiment
, The width of the unnecessary pulse becomes shorter.

This is because the current flowing during the diode period is a current regenerated by the DC power supply 58, and the energy of the inductance is released in a short time.

Therefore, even under the condition that the load is heavy and the current is large, better operation of the comparing means 70 can be expected as compared with the first embodiment.

However, the amount of change in current (dI / dt) during the diode period is large, and noise tends to be disadvantageous as compared with the first embodiment.

(Embodiment 3) FIG. 4 shows an operation waveform diagram in an embodiment using the fourth aspect.

In the third embodiment as well, the circuit configuration is the same as that of the first embodiment shown in FIG. 1, and the drive circuit 65 includes a high-potential-side switching element 59, 60, 61 and a low-potential-side switching element 62. As shown in the first embodiment, 63 and 64 are subjected to pulse width modulation only during the first half 60-degree period, and are controlled to be on during the second half of the electrical angle period of 60 degrees.

In the present embodiment, the reference value generating means 67 provides the duty ratio of the pulse width modulation, that is, du.
The output value is changed according to ty.

As a specific method for generating the reference value, as described in the first embodiment, the duty ratio of the Ss signal is changed so that the duty ratio is changed in synchronization with the switching of the switching element. Has become.

In FIG. 4, (a) is a waveform diagram of V1 and V2 when the duty of pulse width modulation is 80% in the first half of the conduction period of each switching element during the electrical angle of 60 degrees, and (a). FIG. 7 shows voltage waveform diagrams of V1 and V2 when the duty is 25%, (c) shows a voltage waveform diagram of the output V3 of the comparing means 70, and (d) shows an output voltage waveform of the unnecessary pulse removing circuit 71. Are under the same conditions.

Even if the speed is the same, if the duty value of the pulse width modulation is different, the voltage waveform of V1 between times t3 and t4 and between times t6 and t7 slightly changes. In this embodiment, the reference value V
Since the value of 2 is changed according to the duty, as a result, the comparison means 70 outputs an edge at the same timing t10 and t11 under any of the duty conditions (a) and (b). In any of the duty conditions, the switching operation of the switching element is performed from the drive circuit 65 in a state of being delayed by the time td in the delay means 72, and the position detection operation is performed satisfactorily.

(Embodiment 4) FIG. 5 is a circuit diagram of a current detecting means 90 according to an embodiment of the present invention. The current detecting means 90 includes a resistor 91 connected in series to a negative terminal of the DC power supply 58, a peak hold circuit 92 for detecting a peak value of a voltage generated in the resistor 91, and an output voltage of the peak hold circuit 92 for amplifying a drive voltage. It has an amplifier 93 for outputting the DC power 65 and a 5V DC power supply 94.

The peak hold circuit 92 includes the diode 9
5, a capacitor 96 and a resistor 97.

Here, the left terminal of the resistor 91 has a lower potential, and a negative voltage is generated with respect to the ground.

Therefore, the peak hold circuit 92
The output voltage of the peak hold circuit 92 has a characteristic that the negative value becomes larger with respect to the ground as the load becomes higher as the load voltage becomes higher. Will have.

In this regard, the amplifier 93 is a general inverting amplifier circuit using an operational amplifier, so that the sign of the output is inverted and the output voltage increases when the current is large. Can be

Further, the voltage drop due to the diode 95 can be corrected in the amplifier 93, so that the influence of the fluctuation of the forward voltage drop of the diode 95 on the temperature can be canceled. .

Note that the configuration other than the above is the same as that of the first embodiment.

The operation is performed in the above configuration.

FIG. 6 is an operation waveform diagram in the present embodiment in a state where the load torque of the motor 46 is small, the current is small, and the motor 46 is operating at a relatively high speed.

In this case, since the current is small, the energy stored in the inductance of each winding in the motor 46 is small, and the diode periods immediately after t3 and t6 are relatively short, and the induction period is proportional to the speed. Since the power is also large, it is possible to sufficiently detect the intersection between V1 and V2 between t3 and t4 and between t6 and t7, even if V2 has a constant value as shown in FIG.

In this embodiment, when the output of the current detecting means 90 is small, the operation is performed by setting V2 to a direct current (constant value) near the center of the amplitude of V1 as shown in FIG. It is to be done.

FIG. 7 is an operation waveform diagram of the fourth embodiment in a state where the motor 46 is operated at substantially the same speed as that of FIG. 6, in which the load torque of the motor 46 is large and the current is large. is there.

In this case, since the current is large, the energy stored in the inductance is large, and the diode period is long. Therefore, the period during which the voltage waveform due to the induced electromotive force appears in V1 is shortened. t
Between the four, the peak value of V1 does not cross V2 in the case of FIG. 6 indicated by the dashed line.

However, in this embodiment, the current detecting means 90 detects that the current is large, and raises or lowers the voltage waveform of V2 at every electrical angle 60 as shown in FIG. As a result, the intersection of V1 and V2 clearly exists.

In the present embodiment, when the current is larger than the DC value indicated by the one-dot chain line, V2 is increased or decreased by 1.1 V according to the output of the current detecting means 90.

As a result, even in the high load state where the current value is large, the intersections t10 and t11 of V1 and V2 can be detected, and the position can be detected.

Note that the value of 1.1 V in FIG.
If necessary, it can be changed continuously in accordance with the output of the current detecting means 90.

In particular, when the motor 46 has a large inductance such as a copper machine, and when the current is large, the diode period becomes very long.
Even under such conditions, by employing the configuration of the present embodiment, it is possible to ensure sufficient position detection characteristics.

(Embodiment 5) FIG. 8 shows an operation waveform diagram in another embodiment using the first aspect.

In the first aspect, the switching element that performs pulse width modulation may perform pulse width modulation only on the high potential side or pulse width modulation only on the low potential side.

In FIG. 8, (a) is an on / off waveform of the high-potential side switching element 59, (a) is an on / off waveform of the low-potential side switching element 62, and (c) is an output terminal 55.
(D) is the voltage waveform of V1 and V2, (E) is the waveform of the output V3 of the comparison means 70, and (F) is the output waveform of the unnecessary pulse removing circuit 71.

In the present embodiment, unlike the above-described embodiments, the high potential side switching elements 59, 60, 61 are always set to 15.6 by the operation of the drive circuit 65.
Pulse width modulation is performed at a carrier frequency of 1 kHz, and the electrical potential of the low-potential side switching elements 62, 63, and 64 is 1 electrical angle.
On is maintained for a period of 20 degrees.

Even with such control, the voltage equivalently applied to each winding of the motor 46 is proportional to the voltage of the DC power supply 58 multiplied by the duty value of pulse width modulation.

However, the period of the diode current is different between immediately after the high-potential side switching element 59 is turned off and immediately after the low-potential side switching element 62 is turned off. Since the voltage at the output terminal 55 rises to the potential of the DC power supply 58, a high voltage is also seen at V1, and the diode period ends in a short time.

In this embodiment, the reference value V2 is
Since the setting is such that a reliable intersection is obtained for one waveform, a position detection signal having an edge at times t10 and t11 can be obtained.

In the present embodiment, the driving is performed by switching the switching elements with the delay time of td1 and td2 provided by the delay means 72 from each of t10 and t11.

That is, in this embodiment, there is an asymmetric operation in which all the high-potential side switching elements are turned on / off by pulse width modulation, and the low-potential side switching elements are kept on for a period of 120 degrees. That is, V2 is output in response thereto, and the switching operation of the next switching element can be performed at the correct timing by using different values for the delay time such as td1 and td2. It is.

(Embodiment 6) FIG. 9 shows a peripheral circuit diagram of the delay means 72 in an embodiment using the tenth aspect.

The current detecting means 98 and the speed detecting means 99 for detecting the current inside the inverter device are provided. The current detecting means 98 has the same circuit configuration as the current detecting means 90 described in the fourth embodiment. An analog / digital conversion circuit is further connected to the output, and an 8-bit output is performed.

On the other hand, the speed detecting means 99 is constituted by a digital counter circuit, and outputs an 8-bit digital value corresponding to the speed of the motor 46.

In this type of inverter device, since the speed of the motor 46 has a fixed relationship with the operating frequency of the inverter circuit 47, specifically, the speed detecting means 99 determines the operating frequency of the inverter circuit 47 or , Which can detect the switching frequency of each switching element, and can be easily configured by processing a signal from the drive circuit 65.

Although the frequency is used here, it is also possible to measure the time of one cycle which is the reciprocal of the frequency.
Also, the time between the switching times of the switching elements may be measured, and any configuration may be used as long as it outputs a value that changes according to the rotation speed.

In this embodiment, the current detecting means 9
8 and the output of the speed detecting means 99 are digitally processed. However, the present invention is not limited to digital processing, and an output from an analog circuit may be used.

The ROM 100 is a read-only memory having 16 address buses. The output from the current detecting means 98 is input to the lower 8 bits of the address bus.
The output of the speed detecting means 99 is input to the upper 8 bits.

The data bus of the ROM 100 is 16 bits and is connected to the digital counter 101.

A clock signal of 15.6 kHz is input from the clock oscillator 102 to the counter 101, and the carry signal is supplied to the CL of the D flip-flop 103.
It is connected to the OCK terminal.

The LOAD terminal of the counter 101 has EX
An OR gate 104 is connected, and a resistor 105 and a capacitor 106 are connected to one of the inputs of the EXOR gate 104.

The other terminal of the resistor 105 is connected to E
Connected to the other input terminal of the XOR gate 104,
An EXOR gate 107 is connected to this, and an EXO gate 107 is further connected.
The R gate 108 is connected.

Each of IN1, IN2, and IN3 is an input terminal, which is connected to the output of the unnecessary pulse removing circuit 71. OUT1, OUT2, and OUT3 are driving circuits 65.
Is output to

FIG. 10 is an operation waveform diagram showing the operation of IN1.
9A shows an output signal (A) after delay processing when a signal as shown in FIG.

That is, when IN1 changes from low to high, the output of the EXOR gate 107 changes from low to high,
Or it changes from high to low.

Here, IN2 and IN3 always change from high to low since one of them is always high and the other is low when operating as a normal inverter device. .

However, no matter how the output of the EXOR gate 107 changes, the output of the EXOR gate 104 produces a high signal for only about 100 microseconds, which is output to the LOAD terminal of the counter 101. By being input, 16-bit data from the data bus of the ROM 100 is set.

After the data is set, an edge every 64 microseconds from the clock oscillator 102 causes
The counter 101 counts up gradually.

When all 16 bits of the counter 101 become high, the carry signal rises from low to high, and the input signals applied to D1 to D3 at that moment are output to Q1 to Q3. As a result, a delayed signal as shown in (a) is output.

Therefore, if the signal output from ROM 100 is small, the time until the carry signal rises becomes long, and td becomes large.

Conversely, if the signal output from ROM 100 is large, the time until the carry signal rises becomes short, and td becomes small.

As described above, the delay time is determined in accordance with the digital value output from the ROM 100. In this embodiment, the address bus of the ROM 100 is output from the current detecting means 98 and the speed detecting means 99. Therefore, the contents of the address determined by the combination are output from the data bus of the ROM 100.

Therefore, the delay time td can be set to an optimum value according to the current value and the speed, and the output value of the reference value generating means is changed to the output value of the current detecting means 98 and the output value of the speed detecting means 99. The value is a function of two inputs of the motor speed.

Thus, even when a motor having a high impedance, such as a copper machine, is used, the torque is almost univocally changed according to the combination of the speed and the torque (operating point). Since there is a characteristic that is determined, the delay time t
Since d is determined, good position detection performance can be improved.

In FIG. 10, for simplicity, IN
Although only 1 and OUT1 are shown, the same applies to the other input / output terminals. In short, when any of IN1 to IN3 changes, the output OUT1 to OUT1 corresponding to it changes after td time from the change time. OUT3 changes.

However, in this embodiment, the delay time t
d is configured so that there is no change in the inputs IN1 to IN3 while the counter 101 is counting up, and if there is a change in the input signal during that time, a normal operation is not performed.

However, in practice, td with an electrical angle of 60 degrees or less is used.
Because it is set and operated, in actual use,
There is no hindrance.

In the present embodiment, the speed detecting means 99 and the current detecting means 98
The delay time is made a function of two inputs, speed and current, by adopting a configuration in which both outputs are put into the address bus of the ROM 100. Is the configuration of claim 8.

When only the speed detecting means 99 is used, the structure of claim 9 is adopted.

In any case, the address bus of the ROM 100 is only about half, and the storage capacity can be greatly reduced.

In particular, depending on the characteristics such as the impedance value of the motor 46, the torque range and the speed range of the load, etc., sufficient position detection performance can be obtained even with a simple configuration as in claims 8 and 9. Obtainable.

Further, in this embodiment, the value of the delay time td of the delay means 72 is a function of the two inputs of the speed detection means 99 and the current detection means 98.
Instead of connecting the output of the data bus No. 00 to the counter 101, a digital-to-analog conversion circuit such as a ladder resistor is connected, and the output is used as the amount of change of the reference value generating means (corresponding to 1.1V in FIG. 7A). ) Is also easy.

According to such a configuration, the configuration of claim 7 can be realized, the reference voltage is changed in accordance with the speed and the value of the current, and the voltage comparison by the comparing means 70 becomes possible. .

Similarly, in claims 5 and 6,
By using only the current detection means 98 and only the speed detection means 99, respectively, a simplified configuration can be realized, and depending on the motor characteristics, the speed range, the torque range, etc.
An inverter device that operates with sufficient reliability can be realized.

Further, for example, in addition to the present embodiment,
If an OM is provided and connected in parallel with the address bus of the ROM 100, and another ROM outputs a digital amount corresponding to a reference value from the data bus, a combination of claim 7 and claim 10 is obtained. In any of the current change due to the torque fluctuation and the speed change, the reference value automatically becomes the optimum value, and the comparing means 70 always operates reliably, and the delay time from the output timing of the comparing means 70 Since the speed and the current are also set, it is possible to realize an excellent inverter device with high reliability and high position detection accuracy.

As the ROM used in this embodiment, a ROM in a microcomputer may be used. A delay time is set by a timer counter provided in the microcomputer, and unnecessary pulses are also removed by the same computer. By performing processing by software,
It is also possible to realize the device with a very simple configuration.

[0146]

As described above, the invention according to the first aspect of the present invention particularly comprises a motor and an inverter circuit for supplying three-phase power to the motor. The inverter circuit includes a three-phase output terminal, a DC power supply, three high-potential-side switching elements, three low-potential-side switching elements, a driving circuit, and position detecting means. And the three high-potential-side switching elements are connected to a high-potential-side terminal of the DC power supply.
The three low-potential-side switching elements are connected between the low-potential-side terminal of the DC power supply and the three-phase output terminals, and the position detecting means is compared with the reference value generating means. Means for comparing the voltage of the three-phase output terminal with the magnitude of the reference value generating means, and the drive circuit has passed the delay time of the delay means from the output of the comparing means. Thereafter, on / off control of the three high-potential-side switching elements and the three low-potential-side switching elements is performed, and the reference value generating means changes an output value in synchronization with the on / off control to detect position. The performance of the means can be ensured, and an inverter device having high reliability can be realized.

The invention described in claim 2 is particularly advantageous in claim 1.
The drive circuit of the inverter device described above, wherein the three high-potential-side switching elements and the three low-potential-side switching elements are each turned on by an electrical angle of 120 degrees, and the pulse width is set to 60 degrees during the first half thereof. The on / off control is performed by modulation, and the on state is maintained during the latter half of 60 degrees, so that the performance of the position detecting means can be ensured, and the noise generated from the device can be reduced. It is possible to realize a reliable and low-noise inverter device.

The invention of claim 3 is particularly advantageous in claim 1.
3. The drive circuit of the inverter device according to claim 1, wherein the three high-potential-side switching elements and the three low-potential-side switching elements are each turned on by an electrical angle of 120 degrees, and a first half of the 60-degree period is on. And the on / off control is performed by pulse width modulation during the period of 60 degrees in the latter half, so that the performance of the position detection means can also be ensured, and an inverter device with particularly improved position detection characteristics is realized. Is what you can do.

The invention described in claim 4 is particularly advantageous in claim 1.
4. The reference value generation of the drive circuit of the inverter device according to claim 3, wherein at least one of the three high-potential-side switching elements and the three low-potential-side switching elements is turned on / off by pulse width modulation. The means has a configuration in which the output value is changed in accordance with the duty ratio of the pulse width modulation, so that a highly reliable inverter device in which the influence of the characteristics of the position detecting means due to the value of the pulse width modulation is eliminated. Can be realized.

The invention described in claim 5 is particularly advantageous in claim 1.
A current detecting means for detecting a current inside the inverter device according to any one of claims 1 to 3, wherein the reference value generating means changes an output value according to an output of the current detecting means. Thus, it is possible to realize an inverter device having excellent position detection characteristics corresponding to a motor having a high impedance, such as a motor having a high impedance.

The invention described in claim 6 is particularly advantageous in claim 1.
The reference value generating means of the inverter device according to the third aspect is configured to change the output value according to the speed of the motor, so that the performance of the position detecting means can be ensured particularly in a wide range of speed. It is possible to realize a possible inverter device.

The invention described in claim 7 is particularly advantageous in claim 1.
4. A current detecting means for detecting a current inside the inverter device according to claim 3, wherein the reference value generating means determines an output value of at least an output value of the current detecting means and a function of two inputs of a speed of the motor. With this configuration, it is possible to realize an inverter device that can secure the performance of the position detection means in a wide range of speeds when the current increases due to the load on the motor.

The invention described in claim 8 is particularly advantageous in claim 1.
8. An amount of phase advance by having a current detecting means for detecting a current inside the inverter device according to claim 7, wherein said delay means changes a delay time according to an output of said current detecting means. And an inverter device having excellent position detection characteristics can be realized.

The invention described in claim 9 is particularly advantageous in claim 1.
The delay means of the inverter device according to claim 6 is configured to change the delay time according to the speed of the motor, so that the correction corresponding to the amount of advance of the phase or the advance time is always performed in a wide range of speed. An inverter device having such excellent position detection characteristics can be realized.

According to a tenth aspect of the present invention, there is provided a current detecting means for detecting a current inside the inverter device according to any of the first to seventh aspects, wherein the delay means sets a delay time at least to the current detecting means. And a function of two inputs of the motor speed, when the current increases due to the load on the motor, and also in a wide range of speeds, always corresponds to the amount of phase advance or the advance time. Since the correction is performed, an inverter device having excellent position detection characteristics can be realized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an inverter device according to a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram of the inverter device.

FIG. 3 is an operation waveform diagram of the inverter device according to the second embodiment.

FIG. 4 is an operation waveform diagram of the inverter device according to the third embodiment.

FIG. 5 is a diagram showing a current detection unit of an inverter device and a peripheral circuit thereof according to a fourth embodiment.

FIG. 6 is an operation waveform diagram when the current of the inverter device is small.

FIG. 7 is an operation waveform diagram when the current of the inverter device is large.

FIG. 8 is an operation waveform diagram of the inverter device according to the fifth embodiment.

FIG. 9 is a main part circuit diagram of an inverter device according to a sixth embodiment.

FIG. 10 is an operation waveform diagram of the inverter device.

FIG. 11 is a circuit diagram of an inverter device according to a conventional technique.

FIG. 12 is an operation waveform diagram when the current of the inverter device is small.

FIG. 13 is an operation waveform diagram when the current of the inverter device is large.

[Explanation of symbols]

 46 Motor 47 Inverter circuit 48/49 Permanent magnet 50 Rotor 51/52/53 Winding 54 Stator 55/56/57 Output terminal 58 DC power supply 59/60/61 High potential side switching element 62/63/64 Low potential Side switching element 65 Drive circuit 66 Position detection means 67 Reference value generation means 70 Comparison means 72 Delay means 90 Current detection means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasudo Kobayashi 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Tomoya Toto 1006 Kadoma Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 5H560 AA10 BB04 BB07 BB12 DA13 EB01 TT07 UA06 XA12

Claims (10)

[Claims] 1. A motor comprising: a motor and an inverter circuit for supplying three-phase power to the motor; the motor having a rotor having permanent magnets and a stator having three-phase windings; A phase output terminal, a DC power supply, three high-potential-side switching elements, three low-potential-side switching elements, a drive circuit, and position detecting means, wherein the three high-potential-side switching elements are connected to the DC power supply. The three low-potential-side switching elements are connected between a high-potential-side terminal and the three-phase output terminals, and the three low-potential-side switching elements are connected between the low-potential side terminal of the DC power supply and the three-phase output terminals. A reference value generating means, a comparing means, and a delaying means;
The drive circuit compares the voltage of the output terminal of the phase with the magnitude of the reference value generation means, and after a delay time by the delay means from the output of the comparison means, the drive circuit and the three high potential side switching elements and the three An inverter device for performing on / off control of the plurality of low-potential side switching elements, and wherein the reference value generating means changes an output value in synchronization with the on / off control. 2. The driving circuit turns on each of the three high-potential-side switching elements and the three low-potential-side switching elements by an electrical angle of 120 degrees, and the first half thereof.
ON / OFF control by pulse width modulation during the
2. The inverter device according to claim 1, wherein the ON state is maintained during a period of 60 degrees in the latter half. 3. The drive circuit turns on each of the three high-potential-side switching elements and the three low-potential-side switching elements by an electrical angle of 120 degrees, and the first half thereof.
2. The inverter device according to claim 1, wherein the ON state is maintained during a period of the second degree, and the ON / OFF control is performed by pulse width modulation during a period of the second half of 60 degrees. 4. A drive circuit controls on / off of at least one of the three high-potential-side switching elements and the three low-potential-side switching elements by pulse width modulation. The inverter device according to any one of claims 1 to 3, wherein an output value is changed according to a conduction ratio of the width modulation. 5. The inverter according to claim 1, further comprising a current detection unit configured to detect a current inside the inverter device, wherein the reference value generation unit changes an output value according to an output of the current detection unit. The inverter device as described. 6. The inverter device according to claim 1, wherein the reference value generating means changes an output value according to a speed of the motor. 7. A current detecting means for detecting a current inside the inverter device, wherein the reference value generating means determines an output value of the current value by at least an output value of the current detecting means and a motor speed.
4. The inverter device according to claim 1, wherein the inverter device is a function of an input. 8. The inverter according to claim 1, further comprising current detection means for detecting a current inside the inverter device, wherein the delay means changes the delay time in accordance with an output of the current detection means. Inverter device. 9. The method according to claim 1, wherein the delay unit changes a delay time according to a speed of the motor.
The inverter device according to the item. 10. A current detecting means for detecting a current inside the inverter device, wherein the delay means sets a delay time as a function of at least two inputs of an output value of the current detecting means and a speed of the motor. The inverter device according to any one of claims 1 to 7.