JP3525622B2 - Control device for brushless motor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for a brushless motor used for a compressor motor of an air conditioner.

[0002]

2. Description of the Related Art Usually, a brushless motor is required to have a detector such as a Hall element for detecting the magnetic pole position of its rotor for operation. However, for example, when the brushless motor is used for a compressor such as an air conditioner, it is used under high temperature and high pressure conditions, and the reliability of the detector cannot be guaranteed. Therefore, these detectors cannot be used.

Therefore, in such a case, a method is used in which a magnetic pole position detector such as a Hall element is not used, but a voltage signal induced in an armature winding is detected and a motor energization signal is generated based on the voltage signal. ing.

A conventional technique of this type is disclosed in Japanese Patent Laid-Open No. 61-61.
Some are described in Japanese Patent Publication No.-88785. This will be described below with reference to the drawings.

FIG. 6 shows an example of a block diagram of a conventional controller for a brushless motor. During operation of the brushless motor 3, a voltage signal corresponding to the rotation speed is induced in the armature winding of the stator 4. The rotor position detecting means 6 generates a rotor position detection signal including position information of the rotor 5 from this voltage signal. FIG. 7 shows the phase characteristics of the analog filter included in the rotor position detecting means 6.

The energization signal generation means 7 generates an energization signal for each semiconductor switching element of the switching means 2 based on the rotor position detection signal obtained by the rotor position detection means 6.

The energizing signal generated by the energizing signal generating means 7 is ANDed with the PWN signal output from the PWM signal generating means 9 by the pulse width modulating means 8 and the switching means 2 is operated by the pulse width modulated energizing signal. The respective semiconductor switching elements are driven to drive the brushless motor.

The operation at the time of starting will be described with reference to FIGS. 6 and 8. In FIG. 8, T is a timer for frequency determination,
B is a drive pattern of each semiconductor switch 2a to 2f in FIG. 6, and M is a rotor position detection signal. By gradually decreasing the count value of the frequency determining timer T, the operating frequency is gradually increased, and the switching of the drive pattern of each semiconductor switching element is repeated for a certain period of time to generate a rotating magnetic field so that the rotor 5 of the brushless motor 3 can be generated. Rotate gradually. After a certain period of time, the drive pattern (2c-2
e) When the rotor position detection signal is detected by the rotor position detection means 6 after the output, the brushless motor is switched to the operation mode by the energization signal generated by the rotor position detection signal as described above. .

[0009]

However, in the above-mentioned conventional configuration, the output of the rotor position detection signal is delayed with respect to the actual position of the rotor 5 due to the phase characteristic of the analog filter of the rotor position detection means 6. There is a problem that the brushless motor 3 cannot be driven with an optimum operating efficiency depending on the frequency because a deviation such as an advance or a delay occurs, which changes depending on the operating frequency.

Further, the phase of the rotor position detection signal advances with respect to the actual position of the rotor 5 due to the phase characteristic of the analog filter when the brushless motor 3 is started, and the rotor position is detected when the drive pattern (2c-2e) is output. There is a problem that a signal may not be detected and a startup failure may occur.

The present invention is to solve such a conventional problem, and to correct the deviation of the energization phase due to the phase characteristic of the analog filter included in the rotor position detecting means, and to provide a brushless motor control device with good operation efficiency. The purpose is to provide.

Another object of the present invention is to control the current phase of the brushless motor with respect to the rotor position detection signal to eliminate the start-up failure of the brushless motor and to construct a highly reliable system.

[0013]

In order to solve the above problems, the present invention provides first energization signal correction means for correcting the deviation of the energization phase due to the phase characteristics of the analog filter of the rotor position detection means. Is.

The first energization signal correction means makes it possible to always operate the brushless motor at an optimum energization phase regardless of the operating frequency, and to achieve optimum efficiency operation of the brushless motor.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is a brushless motor including a stator having a plurality of phases of armature windings and a rotor having a plurality of poles of permanent magnets, and a plurality of semiconductor switching elements. And a switching means composed of a rectifying element, and having an analog filter to detect the voltage signal induced in the armature winding of the brushless motor,
Rotor position detecting means for converting this voltage signal into a rotor position detecting signal, energizing signal generating means for generating an energizing signal of each semiconductor switching element of the switching means from the rotor position detecting signal, and an operating frequency of the brushless motor There is provided a first energization signal correction means that correlates and corrects a deviation in the output timing of the energization signal generated by the phase characteristics of the analog filter.

According to this structure, the deviation of the energization phase due to the phase characteristics of the analog filter of the rotor position detecting means can be corrected, and the brushless motor can always be operated at the optimum energization timing regardless of the frequency. You can

According to a second aspect of the present invention, there is provided a brushless motor including a stator having a plurality of phases of armature windings and a rotor having a plurality of poles of permanent magnets, and a plurality of semiconductor switching elements and rectifying elements. And a rotor position detecting means for detecting a voltage signal induced in an armature winding of a brushless motor having an analog filter and converting the voltage signal into a rotor position detecting signal, and a rotor position. A second energization signal generating means for generating an energization signal for each semiconductor switching element of the switching means from the detection signal, and a second timing for correcting the output timing of the energization signal so that the step-out tolerance increases when the operating frequency of the brushless motor is changed. An energization signal correction means is provided.

According to this structure, the operating frequency can be changed without stepping out the brushless motor.

According to a third aspect of the present invention, in addition to the first aspect of the present invention, drive signal output means for outputting a drive signal for each semiconductor switch of the switching means regardless of the position of the rotor of the brushless motor, and the drive signal. By driving each semiconductor switching element with, the semiconductor switching element is driven by the energization signal generated from the rotor position detection signal from the start mode in which the rotating magnetic field is generated in the stator to forcibly operate the brushless motor. Current phase control that controls the current phase of the brushless motor with respect to the rotor position detection signal in order to correct the deviation of the energization timing caused by the phase characteristics of the analog filter when shifting to the rotor position detection operation mode that drives the brushless motor. Means are provided.

With this configuration, it is possible to eliminate the problem of start-up failure due to step-out or the like when the brushless motor shifts from the start-up mode to the rotor position detection operation mode.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) In FIG. 1, 1 is a direct current power source constructed by rectifying a general alternating current power source by a rectifying bridge circuit or the like, 2 is rectification of semiconductor switching elements such as a plurality of bipolar transistors and diodes. The switching means 3 composed of elements is a brushless motor, and is composed of a stator 4 composed of armature windings of a plurality of phases and a rotor 5 composed of permanent magnets of a plurality of poles.

Further, 6 is a rotor position detecting means for generating a position detection signal of the rotor 5 from the counter electromotive voltage induced in the armature winding of the stator 4, and 7 is a switching means from the position signal of the rotor 5. 2. Energization signal generating means for generating the energization signal of each semiconductor switch, 10 is first energization signal correction means for advancing or delaying the output of the energization signal for a predetermined time, and 9 is a PWM signal having an on / off ratio according to the operating frequency. To generate P
The WM signal generation means 8 is a pulse width modulation means for taking the logical product of the energization signal and the PWM signal.

A method for improving the operation efficiency of the brushless motor control device configured as described above will be described.

During operation of the brushless motor 3, a voltage signal corresponding to the rotation speed is induced in the armature winding of the stator 4. The rotor position detecting means 6 generates a rotor position detection signal including position information of the rotor 5 from this voltage signal. At this time, due to the phase characteristics of the analog filter included in the rotor position detecting means 6, a deviation such that the output of the rotor position detection signal advances or is delayed with respect to the actual position of the rotor 5 occurs, which causes a difference in the operating frequency. Change depending.

The energization signal generation means 7 generates an energization signal for each semiconductor switching element of the switching means 2 based on the rotor position detection signal obtained by the rotor position detection means 6.

This energization signal contains an error due to the phase characteristic of the analog filter included in the rotor position detecting means 6 as described above, and this error changes depending on the operating frequency, so that the phase in the most efficient operating state may vary depending on the frequency. There may be a deviation from the.

Therefore, the energization signal adjusting means 10 performs temporal correction such that the output of the energization signal is advanced or delayed for a certain period of time according to the operating frequency, and is output at a timing that always realizes optimum operating efficiency regardless of the operating frequency. To do.

The energization signal corrected by the energization signal adjusting means 10 is output from the PWM signal generating means 9 in PWM.
A logical product of the signal and the pulse width modulation means 8 is obtained, and each semiconductor switching element of the switching means 2 is driven by the pulse width modulated energization signal, and the brushless motor is driven with optimum operating efficiency.

FIG. 2 is a diagram showing a specific configuration of the block diagram of FIG. 1, and the same components as those in FIG. 1 or those having the same functions are designated by the same reference numerals.

In the figure, 1 to 5 are exactly the same as in FIG. Reference numeral 6 denotes a rotor position detecting means, which includes three analog filter circuits 11, 12, 13 and a combination comparing circuit 14, 15, 1.
It is composed of 6. 7 to 10 have the same functions as those in FIG. 1 and are configured by using a logic circuit or a microcomputer.

The details will be described below. When the brushless motor 3 is in operation, a voltage signal is induced in the armature winding of the stator 4. This voltage signal is integrated by the analog filter circuits 11 to 13 of the rotor position detecting means 6, and further converted into a signal including the position information of the rotor 5 from the integrated three-phase voltage signal in the combining and comparing circuits 14 to 16. To be done.

At this time, the analog filter circuits 11 to 13
Has the phase characteristic shown in FIG. 7, the output of the rotor position detecting means 6 changes depending on the operating frequency of the brushless motor.

As a result, the output timing of the energization signal of each semiconductor switching element of the switching means 2 generated by the energization signal generation means 7 also changes according to the operating frequency, and the optimum energization signal corresponding to the actual position of the rotor 5 is obtained. Can't get

Therefore, the first energization signal correcting means 10 corrects the time advance or delay of the output of the energization signal with respect to the rotor position detection signal caused by the phase characteristics of the analog filter circuits 11 to 13 described above. Each semiconductor switching element of the switching means 2 can be driven at the optimum energization timing suitable for the position of the rotor 5.

As described above, by correcting the deviation of the energization phase with respect to the rotor position detection signal caused by the phase characteristics of the analog filter circuits 11 to 13, it is possible to realize a controller for a brushless motor with high operating efficiency. it can.

(Embodiment 2) In FIG. 3, reference numeral 1 is a DC power supply constructed by rectifying a general AC power supply by a rectifying bridge circuit, and 2 is rectification of semiconductor switching elements such as a plurality of bipolar transistors and diodes. The switching means 3 composed of elements is a brushless motor, and is composed of a stator 4 composed of armature windings of a plurality of phases and a rotor 5 composed of permanent magnets of a plurality of poles.

Further, 6 is a rotor position detecting means for generating a position detecting signal of the rotor 5 from the counter electromotive voltage induced in the armature winding of the stator 4, and 7 is a switching means from the position signal of the rotor 5. 2. Energization signal generating means for generating an energization signal for each semiconductor switch, 10 is second energization signal correction means for advancing or delaying the output of the energization signal for a predetermined time, and 9 is a PWM signal having an on / off ratio according to the operating frequency. To generate P
The WM signal generation means 8 is a pulse width modulation means for taking the logical product of the energization signal and the PWM signal.

A method for improving the step-out torque of the brushless motor 3 at the time of changing the operating frequency in the brushless motor control device configured as described above will be described.

During stable operation of the brushless motor 3, the rotor position detection means 6 obtains phase information of the rotor 5 from the voltage signal induced in the armature winding of the stator 4, and the energization signal generation means 7 further An energization signal for driving each switching element of the switching means 2 is obtained, and thereby the brushless motor continues stable operation.

When the operating frequency is changed, the phase characteristic changes when the frequency changes depending on the weight of the load, and in particular, when the phase advances, the brushless motor 3 may be out of step.

Then, the energization signal obtained from the position information of the rotor 5 detected by the rotor position detecting means 6 is set to the second value.
The energization signal correction means 17 performs time correction such as advancing or delaying the output timing of the energization signal with respect to the rotor position detection signal so that the step-out tolerance of the brushless motor 3 increases only when the frequency changes. After the frequency stabilizes, the correction of the energization signal is canceled and the normal operating condition is restored.

As a result, the step-out torque can be increased with respect to the frequency change, and a more reliable system can be provided as compared with the conventional case.

(Embodiment 3) In FIG. 4, 1 is a DC power supply constructed by rectifying a general AC power supply by a rectifying bridge circuit, and 2 is rectification of semiconductor switching elements such as a plurality of bipolar transistors and diodes. The switching means 3 composed of elements is a brushless motor, and is composed of a stator 4 composed of armature windings of a plurality of phases and a rotor 5 composed of permanent magnets of a plurality of poles.

Further, 6 is a rotor position detecting means for generating a position detecting signal of the rotor 5 from the counter electromotive voltage induced in the armature winding of the stator 4, and 7 is a switching means from the position signal of the rotor 5. 2. Energization signal generating means for generating an energization signal for each semiconductor switch, 10 is second energization signal correction means for advancing or delaying the output of the energization signal for a predetermined time, and 9 is a PWM signal having an on / off ratio according to the operating frequency. To generate P
The WM signal generation means 8 is a pulse width modulation means for taking the logical product of the energization signal and the PWM signal.

Reference numeral 18 is a drive signal output means for outputting a drive signal for each semiconductor switching element of the switching means 2 regardless of the position of the rotor 5 of the brushless motor 3, and 1
Reference numeral 9 is a current phase control means for controlling the current phase when the brushless motor 3 is started.

With respect to the brushless motor control device configured as described above, a method for eliminating the starting failure of the brushless motor 3 will be described.

At start-up, the brushless motor is stationary, so that no voltage signal is generated in the armature winding of the stator 4. Therefore, the drive is externally forcibly performed until the rotor position detection signal is generated.

That is, by driving each semiconductor switching element of the switching means 2 at a low frequency by the drive signal output means 18, a low frequency rotating magnetic field is generated from the armature winding of the stator 4. The rotor 5 is pulled by the rotating magnetic field and starts to start, and the rotation speed gradually increases.
A voltage signal is induced in the armature winding of.

After a certain period of time, the operation mode is switched from the operation by the drive signal of the drive signal output means 18 to the operation of the brushless motor 3 by the energization signal generated from the rotor position detection signal. At this time, due to the phase characteristics of the analog filter of the rotor position detecting means 6 shown in FIG. 7, the phase advances at a low frequency such as at start-up, so that the rotor position detection signal has a drive pattern (2c−) as shown in FIG. 2e) It may be detected before the output, resulting in a startup failure.

Therefore, in order to eliminate such a start-up failure, the current phase control means 19 corrects the deviation of the energization timing caused by the phase characteristic of the analog filter of the rotor position detection means 6 with respect to the rotor position detection signal. The current phase of the brushless motor 3 is controlled.

A specific method will be described below with reference to FIG. In FIG. 5, T is a frequency determining timer, and D is a delay time creating timer, which can advance or delay the current phase. B is a drive pattern of each semiconductor switch 2a to 2f in FIG.
Indicates a rotor position detection signal.

Normally, the drive pattern is switched as soon as the frequency determining timer T counts, but in FIG. 5, the drive pattern is switched after the count of the delay time creating timer is completed, whereby the drive signal output means 18 is provided. The output timing of the energization signal is delayed for a certain period of time with respect to the rotating magnetic field generated by the drive signal.

The drive pattern is switched in this procedure,
After a certain time has passed, the delay time generation timer energizes only when the forced magnetic field operation is switched to the energization signal generated by the rotor position detection signal, that is, when the drive pattern (2c-2e) is output. Do not delay the signal.

As a result, the current phase can be advanced with respect to the rotor position detection signal, and the time margin a necessary for detecting the rotor position detection signal can be increased,
Start-up failure can be eliminated.

With the above procedure, it is possible to construct a system having a very high reliability for activation.

The apparatus of this embodiment shown in FIGS.
Although the pulse width modulation by the PWM signal is applied to the energization signal of each semiconductor switching element of the switching means 2,
It goes without saying that the present invention can also be applied to the case where pulse width modulation is not performed.

[0058]

As is apparent from the above-described embodiment, the invention according to claim 1 has a brushless motor, a switching means including a plurality of semiconductor switching elements and a rectifying element, and an analog filter. While detecting the voltage signal induced in the armature winding,
Rotor position detecting means for converting this voltage signal into a rotor position detecting signal, energizing signal generating means for generating an energizing signal of each semiconductor switching element of the switching means from the rotor position detecting signal, and an operating frequency of the brushless motor A first energization signal correction unit that correlates and corrects a deviation in the output timing of the energization signal generated by the phase characteristics of the analog filter is provided.

According to this configuration, during the operation of the brushless motor, by correcting the deviation of the output timing of the energization signal caused by the phase characteristics of the analog filter, it is possible to always perform the optimum efficiency operation regardless of the frequency, and the air conditioner as a whole. This has the effect of reducing power consumption.

The invention described in claim 2 has a brushless motor, a switching means including a plurality of semiconductor switching elements and a rectifying element, and an analog filter to detect a voltage signal induced in an armature winding of the brushless motor. At the same time, a rotor position detecting means for converting this voltage signal into a rotor position detecting signal, an energizing signal generating means for generating an energizing signal for each semiconductor switching element of the switching means from the rotor position detecting signal, and a brushless motor operation. A second energization signal correction means is provided to correct the output timing of the energization signal so that the step-out tolerance increases when the frequency is changed.

According to this structure, the operating frequency can be changed without stepping out the brushless motor, and the system having higher reliability can be constructed.

According to a third aspect of the present invention, in addition to the first aspect of the present invention, a drive signal output means for outputting a drive signal of each semiconductor switch of the switching means regardless of the position of the rotor of the brushless motor, and a drive signal. Each semiconductor switch is driven by the energization signal generated from the rotor position detection signal from the start mode in which the rotating magnetic field is generated in the stator to drive the brushless motor forcibly by driving each semiconductor switch with the brushless motor. At the time of shifting to the rotor position detection operation mode, the current phase control means for controlling the current phase of the brushless motor with respect to the rotor position detection signal in order to correct the deviation of the energization timing generated by the phase characteristics of the analog filter It is provided.

With this configuration, it is possible to eliminate the problem of start-up failure due to step-out when the brushless motor shifts from the start-up mode to the rotor position detection operation mode. The effect is that a highly reliable system can be constructed.

[Brief description of drawings]

FIG. 1 is a block diagram of a controller for a brushless motor showing an embodiment of the present invention.

FIG. 2 is a block diagram of a controller for a brushless motor of the same embodiment.

FIG. 3 is a block diagram of a brushless motor control device according to another embodiment of the present invention.

FIG. 4 is a block diagram of a brushless motor control device according to another embodiment of the present invention.

FIG. 5 is a start chart of a brushless motor according to another embodiment of the present invention.

FIG. 6 is a block diagram of a conventional brushless motor control device.

FIG. 7 is a phase characteristic diagram of an analog filter included in the rotor position detecting means in the conventional example.

FIG. 8 is a starting chart of a brushless motor in a conventional example.

[Explanation of symbols]

1 DC power supply 2 Switching means 2a to 2f semiconductor switch 3 brushless motor 4 stator 5 rotor 6 Rotor position detection means 7 Energization signal generation means 8 Pulse width modulation means 9 PWM signal generating means 10 First energization signal correction means 11-13 Analog filter circuit 14-16 Synthetic comparison circuit 17 Second energization signal correction means 18 Drive signal output means 19 Current phase control means

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02P 6/18

Claims (3)

(57) [Claims] 1. A brushless motor comprising a stator having a plurality of phases of armature windings and a rotor having a plurality of poles of permanent magnets, a switching means including a plurality of semiconductor switching elements and a rectifying element, and an analog filter. A rotor position detecting means for detecting a voltage signal induced in the armature winding of the brushless motor and converting the voltage signal into a rotor position detection signal; and the switching from the rotor position detection signal. A first energization signal generating means for generating an energization signal of each semiconductor switching element of the means, and a first correction for correlating with an operating frequency of the brushless motor and for correcting an output timing deviation of the energization signal generated by a phase characteristic of the analog filter. A brushless motor control device provided with the energization signal correction means. 2. A brushless motor comprising a stator having a plurality of phases of armature windings and a rotor having a plurality of poles of permanent magnets, a switching means including a plurality of semiconductor switching elements and a rectifying element, and an analog filter. A rotor position detecting means for detecting a voltage signal induced in the armature winding of the brushless motor and converting the voltage signal into a rotor position detection signal; and the switching from the rotor position detection signal. Means for generating energization signals for each semiconductor switching element, and second energization signal correction for correcting the output timing of the energization signals so that the step-out tolerance increases when the operating frequency of the brushless motor is changed. Controller for brushless motor provided with means. 3. A drive signal output means for outputting a drive signal for each semiconductor switching element of the switching means irrespective of the position of the rotor of the brushless motor, and for driving each semiconductor switching element by the drive signal,
From a start mode in which a rotating magnetic field is generated in the stator to drive the brushless motor, a rotor position detection operation mode in which the semiconductor switching elements are driven by the energization signal generated from the rotor position detection signal to drive the brushless motor. The current phase control means for controlling the current phase of the brushless motor with respect to the rotor position detection signal is provided in order to correct the deviation of the energization timing caused by the phase characteristic of the analog filter at the time of transition to (1).
A controller for the brushless motor described.