JP3174000B2 - Compressor driving method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for driving a compressor, and more particularly to a method and an apparatus for driving a compressor by a brushless DC motor controlled by an inverter.

[0002]

2. Description of the Related Art As a motor having higher efficiency than an AC motor, a permanent magnet is attached to a rotor instead of a rotor winding, so that secondary copper loss caused by current flowing through the rotor winding is obtained. There is known a brushless DC motor that eliminates the above problem. In addition, the need for power saving of air conditioners has increased, and the compressor drive has been replaced with the conventional AC motor / inverter.
A brushless DC motor drive control device that mainly drives and controls a brushless DC motor using a voltage-type inverter has been used.

When a compressor is driven by using this brushless DC motor drive control device, the pressure load torque of the compressor fluctuates greatly during one rotation, so that
Inevitably, the load torque of the brushless DC motor also fluctuates greatly. In such a compressor drive system, an operable load range (hereinafter, simply referred to as a load range) is defined. This load range is determined by the required use range of the compressor drive system, the limit of the output of the brushless DC motor / inverter (hereinafter simply referred to as output), and the strength limit of the component parts (see FIG. 1). . Therefore, in a compressor drive system that drives a compressor by a brushless DC motor controlled by an inverter, for example, in an air conditioner, it is detected whether a load range is exceeded using a thermistor installed in a heat exchanger. However, when it is detected that the load exceeds the load range, control for reducing the rotation speed by an inverter (hereinafter referred to as drooping control) is performed (see FIG. 2A). Also, if a sudden change occurs,
Since the output limit was exceeded, the brushless DC motor stepped out, and stop control was performed (see FIG. 2B).

[0004]

As described above, when the method of detecting whether or not the load exceeds the load range by using a thermistor is adopted, a time delay and variations in elements are large,
It is not possible to accurately detect whether or not the load range is exceeded. Therefore, there is a possibility that a condition that greatly exceeds the limit of the load range may occur, and in such a case, the strength limit of the component parts is exceeded, and the reliability of the entire compressor drive system is impaired. Become.

In order to prevent such inconvenience, as shown in FIGS. 3A and 3B, the output limit,
The strength limit of the component parts must be improved, which inevitably leads to an increase in cost.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and does not improve the output limit and the strength limit of the component parts, and detects the presence or absence of the load range without time delay. It is an object of the present invention to provide a compressor driving method and a compressor driving method which can achieve the compressor accurately and stably drive the compressor.

[0007]

According to a first aspect of the present invention, there is provided a method of controlling a compressor drive, wherein the brushless DC is controlled by an inverter.
When the compressor is driven by the motor, the rotational position of the rotor of the brushless DC motor is detected, and the brushless DC motor is rotated.
The phase correction angle of the electric signal output from the inverter with respect to the position of the rotor of the C motor is set, and the necessary output and rotation of the brushless DC motor are performed in response to the commanded rotation speed and the detected rotation position of the rotor. A compressor driving method for supplying a control signal to an inverter to obtain a number, wherein a compressor load is detected based on a phase correction angle of an electric signal output from the inverter with respect to a rotor position, and the detected compressor load is detected. In this method, a control signal is supplied to the inverter so as not to exceed the limit load of the compressor system.

According to a second aspect of the present invention, there is provided a compressor driving device for driving a compressor by a brushless DC motor controlled by an inverter, wherein a rotation position detecting means for detecting a rotation position of a rotor of the brushless DC motor. A phase correction angle setting means for setting a phase correction angle of an electric signal output from the inverter with respect to the position of the rotor of the brushless DC motor, and a response to the command rotational speed and the detected rotational position of the rotor. An inverter control means for supplying a control signal to the inverter so as to obtain an output and a rotation speed of the brushless DC motor, wherein a phase correction angle of an electric signal output by the inverter with respect to a position of the rotor is provided. A compression load detection unit configured to detect a compression load based on the detected compression load. And supplies a control signal to the inverter so as not to exceed the limit load of the compressor system Zui.

According to a third aspect of the present invention, when the compressor is driven by the brushless DC motor controlled by the inverter, the rotational position of the rotor of the brushless DC motor is detected, and the rotor of the brushless DC motor is detected. Set the phase correction angle of the electric signal output by the inverter with respect to the position, and obtain the necessary output and rotation speed of the brushless DC motor in response to the command rotation speed and the detected rotation position of the rotor. A compressor driving method for supplying a control signal to a compressor system, comprising detecting a compression load based on a phase correction angle of an electric signal output from an inverter with respect to a position of a rotor, and detecting a compression load based on the detected compression load. In this method, a control signal is supplied to the inverter to control the rotation speed of the brushless DC motor so as not to exceed the limit load.

According to a fourth aspect of the present invention, when the compressor is driven by the brushless DC motor controlled by the inverter, the rotational position of the rotor of the brushless DC motor is detected and the rotor of the brushless DC motor is detected. Set the phase correction angle of the electric signal output by the inverter with respect to the position, and obtain the necessary output and rotation speed of the brushless DC motor in response to the command rotation speed and the detected rotation position of the rotor. A compressor driving method for supplying a control signal to a compressor system, comprising detecting a compression load based on a phase correction angle of an electric signal output from an inverter with respect to a position of a rotor, and detecting a compression load based on the detected compression load. In response to the detection of exceeding the critical load of the compressor system, and responding to the detection of exceeding the critical load of the compressor system. Which is a method for supplying an inverter control signal to stop.

According to a fifth aspect of the present invention, when the compressor is driven by the brushless DC motor controlled by the inverter, the rotational position of the rotor of the brushless DC motor is detected, and the rotor of the brushless DC motor is detected. Set the phase correction angle of the electric signal output by the inverter with respect to the position, and obtain the necessary output and rotation speed of the brushless DC motor in response to the command rotation speed and the detected rotation position of the rotor. A compressor driving method for supplying a control signal to a compressor system, comprising detecting a compression load based on a phase correction angle of an electric signal output from an inverter with respect to a position of a rotor, and detecting a compression load based on the detected compression load. Supply a control signal to the inverter to control the rotation speed of the brushless DC motor so as not to exceed the limit load of
Based on the detected compression load, it has been detected that a sudden change in the compression load that may exceed the limit load of the compressor system has occurred, and it has been detected that the sudden change in the compression load has occurred. , A control signal is supplied to the inverter to stop the brushless DC motor.

[0012]

According to the brushless DC motor drive control method of the first aspect, a brushless DC motor controlled by an inverter is provided.
Brushless D to drive compressor by motor
Detects the rotational position of the rotor of the C motor, and
The phase correction angle of the electric signal output from the inverter with respect to the position of the rotor of the motor is set, and in response to the command rotation speed and the detected rotation position of the rotor, the necessary brushless D
In supplying a control signal to the inverter to obtain the output and the number of rotations of the C motor, a compression load is detected based on a phase correction angle of an electric signal output from the inverter with respect to a position of the rotor, and the detected compression load is detected. Since the control signal is supplied to the inverter based on the load so as not to exceed the limit load of the compressor system, whether or not the load range is exceeded without improving the output limit and the strength limit of component parts. Detection can be achieved accurately without delay and the compressor can be driven stably.

According to the second aspect of the present invention, in order to drive the compressor by the brushless DC motor controlled by the inverter, the rotational position of the rotor of the brushless DC motor is detected by the rotational position detecting means. The phase correction angle setting means sets the phase correction angle of the electric signal output from the inverter with respect to the position of the rotor of the brushless DC motor, and responds to the command rotation speed and the detected rotational position of the rotor by the inverter control means. In supplying a control signal to the inverter in order to obtain a necessary output and rotation speed of the brushless DC motor, a compression load detecting means detects a phase correction angle of an electric signal output from the inverter with respect to a position of the rotor. The compressor load is detected, and the inverter control means controls the compressor system based on the detected compression load. Supplying a control signal to the inverter so as not to exceed the limit load systems out. Therefore, without increasing the power limit and the strength limit of the component parts,
Detection of whether or not the load range is exceeded can be accurately achieved without time delay, and the compressor can be driven stably.

According to the third aspect of the present invention, in order to drive the compressor by the brushless DC motor controlled by the inverter, the rotation position of the rotor of the brushless DC motor is detected and the rotation of the brushless DC motor is detected. To set the phase correction angle of the electric signal output by the inverter with respect to the position of the rotor, and to obtain the necessary output and rotation speed of the brushless DC motor in response to the command rotation speed and the detected rotation position of the rotor. In supplying a control signal to the inverter, a compression load is detected based on a phase correction angle of an electric signal output from the inverter with respect to a position of the rotor, and a limit load of the compressor system is determined based on the detected compression load. Control signal is supplied to the inverter to control the number of revolutions of the brushless DC motor so as not to exceed the output limit. Formed component parts without improving the strength limit of not delay the detection of whether exceeds the load time range, and accomplished accurately, the compressor can be stably driven.

According to the fourth aspect of the present invention, in order to drive the compressor by the brushless DC motor controlled by the inverter, the rotational position of the rotor of the brushless DC motor is detected and the rotation of the brushless DC motor is controlled. To set the phase correction angle of the electric signal output by the inverter with respect to the position of the rotor, and to obtain the necessary output and rotation speed of the brushless DC motor in response to the command rotation speed and the detected rotation position of the rotor. In supplying a control signal to the inverter, a compression load is detected based on a phase correction angle of an electric signal output from the inverter with respect to a position of the rotor, and a limit load of the compressor system is determined based on the detected compression load. The brushless DC motor is stopped in response to detecting that the load exceeds the limit load of the compressor system. Since the control signal is supplied to the inverter as much as possible, the detection of whether or not the load range is exceeded is achieved without time delay and accurately without improving the output limit and the strength limit of the component parts. When the load exceeds the limit load, the brushless DC motor can be reliably stopped.

According to the fifth aspect of the present invention, when the compressor is driven by the brushless DC motor controlled by the inverter, the rotational position of the rotor of the brushless DC motor is detected and the brushless DC motor is driven. The phase correction angle of the electric signal output from the inverter with respect to the position of the rotor is set, and the necessary output and rotation speed of the brushless DC motor are obtained in response to the command rotation speed and the detected rotation position of the rotor. In supplying a control signal to the inverter, the compressor load is detected based on the phase correction angle of the electric signal output from the inverter with respect to the rotor position, and the limit of the compressor system is determined based on the detected compression load. A control signal is supplied to the inverter to control the rotation speed of the brushless DC motor so as not to exceed the load, and the detected compression load is supplied to the inverter. A sudden change in the compression load that may exceed the critical load of the compressor system, and responds to the detection of the occurrence of the sudden change in the compression load. Since the control signal is supplied to the inverter to stop the motor, the detection of whether the load range is exceeded or not can be accurately and accurately detected without improving the output limit and the strength limit of component parts. However, based on this detection result, the brushless DC motor can be driven so that the output does not exceed the limit load, and when the output may exceed the limit load due to a sudden change in the compression load,
The brushless DC motor can be reliably stopped.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 4 is a block diagram showing an embodiment of the compressor driving device according to the present invention. The system control block 100 controls the entire compressor system.
An inverter control block 300 for controlling an inverter for driving the brushless DC motor; a required frequency fr from the system control block 100; a phase correction angle θ from the inverter control block 300;
and a command frequency determination unit 200 that receives the p and supplies a command frequency fc to the system control block 100 and the inverter control block 300. Note that the processing of the command frequency determination unit 200 is described in FIGS.
This processing is performed as preprocessing of the speed control unit in FIG. 27 and is combined with processing in the microprocessor 18. That is, the speed calculation unit 19 shown in FIGS.
The command frequency is determined by the command frequency determination unit 200 using the current speed and the speed command output from e as inputs, and the determined command frequency is supplied to the speed control unit 19f to output a voltage command.

FIG. 5 is a schematic diagram showing an example of a brushless DC motor drive control device. The output voltage of the inverter 2 is applied to the brushless DC motor 3. Then, the rotation position of the rotor 3a of the brushless DC motor 3 is detected by a rotation position detection circuit 4, and an output signal from the rotation position detection circuit 4 is supplied to a control circuit 5, and the control circuit 5 controls the electric conduction width. For example, a control command is generated and supplied to the inverter 2 so as to have a predetermined width exceeding 120 ° and 180 ° or less. Further, the compressor 6 is driven by the brushless DC motor 3.

Accordingly, a rotation position detection signal indicating the rotation position of the rotor 3a of the brushless DC motor 3 is obtained by the rotation position detection circuit 4, and a control command is generated in the control circuit 5 based on the rotation position detection signal. Switch (not shown), e.g.
Is controlled so as to have a predetermined energization width of less than or equal to °. FIG. 6 is a diagram schematically showing the configuration of a brushless DC motor having a surface magnet structure, in which a permanent magnet 3b is provided at a predetermined position on the surface of a rotor 3a.
Is attached. The stator 3c has a number of slots 3d around which a stator winding (not shown) is wound. The d-axis indicated by an arrow in the drawing is an axis indicating the direction of the magnetic flux generated by the permanent magnet 3b, and the q-axis is an axis electrically shifted from the d-axis by 90 °.

FIG. 7 is a diagram schematically showing the configuration of a brushless DC motor having an embedded magnet structure, in which a permanent magnet 3f is mounted without being exposed on the surface of a rotor 3e. However, a nonmagnetic material 3g is mounted between the adjacent permanent magnets 3f to prevent a magnetic flux short circuit between the adjacent permanent magnets 3f. The configuration of the stator 3c is the same as that of the brushless DC motor of FIG.

FIG. 8 is a diagram schematically showing the structure of a brushless DC motor drive control device, and FIG. 9 is a diagram showing the internal structure of the microprocessor 18 in FIG. Transistors 12u1, 12
u2, 12v1, 12v2, 12w1, and 12w2 are connected in series to form an inverter 12, and a connection point voltage between each pair of switching transistors is set to a brushless D.
Stator winding 13 of each phase of C motor 13 connected in Y
u, 13v, and 13w. And
The connection point voltage between the switching transistors of each pair is Y
It is also applied to the connected resistors 14u, 14v, 14w, respectively. Note that the switching transistors 12u1,
Protective diodes 12u1d, 12u2d, 12v1d, 12v2d, and 12u2, 12v1, 12v2, 12w1, and 12w2 are provided between the collector and emitter terminals, respectively.
12w1d and 12w2d are connected. In addition, 13a
Indicates a rotor of the brushless DC motor 13. The Hall elements 13hu, 13hv, and 13hw that output signals corresponding to the rotational position of the rotor 13a are provided at predetermined positions affected by the magnetic flux of the rotor 13a. Subscripts u, v, and w are brushless D
It corresponds to the u phase, v phase, and w phase of the C motor 13.

The Y-connected stator windings 13u, 13
The voltage at the neutral point 13d of the resistors v, 13w is supplied to the inverting input terminal of the amplifier 15 via the resistor 15a, and the voltage at the neutral point 14d of the resistors 14u, 14v, 14w connected in Y is not inverted by the amplifier 15 as it is. It is supplied to the input terminal. By connecting a resistor 15b between the output terminal and the inverting input terminal of the amplifier 15, the amplifier 15 operates as a differential amplifier. An output signal output from the output terminal of the amplifier 15 is supplied to an integrator 16 that includes a resistor 16a and a capacitor 16b connected in series.

The output signal from the integrator 16 (the voltage at the node between the resistor 16a and the capacitor 16b) is supplied to a level detection circuit 17, and the level detection signal from the level detection circuit 17 is supplied to a microprocessor 18. As shown in FIG. 10, the level detection circuit 17 inputs the integration signal ∫VMNdt from the integrator 16 to the inverting input terminal of the amplifier 17a via the resistor 17b, and
The non-inverting input terminal a is connected to the ground GND.
The anode of the diode 17c is connected to the output terminal of the amplifier 17a, and the cathode of the diode 17c is connected to the inverting input terminal of the amplifier 17a. The cathode of a diode 17d is connected to the output terminal of the amplifier 17a, and the anode of the diode 17d is connected to the inverting input terminal of the amplifier 17a via a resistor 17e. An inverting input terminal of the amplifier 17f is connected to a connection point between the anode of the diode 17d and the resistor 17e via a resistor 17g. Further, the inverting input terminal of the amplifier 17f and the resistor 17
A resistor 17h between the integrated signal b and one end on the VMNdt side
And connect the non-inverting input terminal of the amplifier 17f to the ground G
Connected to ND. A resistor 17p is connected between the inverting input terminal and the output terminal of the amplifier 17f. Further, the inverting input terminal of the comparator 17j is connected to the output terminal of the amplifier 17f via the resistor 17i.
Is connected to ground G via a capacitor 17k.
Connected to ND. The power supply is connected to the non-inverting input terminal of the comparator 17j via a resistor 17m, and is connected to the ground GND via a resistor 17n. Here, the reference value E3 of the comparator 17j is set by the resistors 17m and 17n. By setting this reference value E3 in correspondence with the maximum efficiency, the brushless DC
Operation can be performed at the point where the efficiency of the motor is maximized.

Hall elements 13hu, 13hv, 13hw
The rotation position detection circuit 20 that outputs a rotation position detection signal indicating the rotation position of the rotor 13a by using the electric signal output from the input device as an input, includes Hall elements 13hu, 13hv, and 13hw.
20u and 20a respectively amplify electric signals from
v, 20w, an OR circuit 20a supplied with output signals of the amplifiers 20u, 20w, an OR circuit 20b supplied with output signals of the amplifiers 20u, 20v, and an amplifier 20
OR circuit 20c to which output signals v and 20w are supplied
And an AND circuit 20d that outputs a rotational position detection signal when supplied with output signals from the OR circuits 20a, 20b, and 20c.

Therefore, when the brushless DC motor 13 is driven according to the position detection,
Hall elements 13hu, 13h for detecting the rotational position of a
The electric signals output from v and 13hw have trapezoidal waveforms having different phases every 120 deg as shown in (A) to (C) in FIG. Then, as shown in (D) in FIG. 11, the rotation position detection circuit 20 outputs a rotation position detection signal whose level switches every 60 deg. Further, the amplifier 15 includes a voltage VM at a neutral point of the resistance circuits 14u, 14v, and 14w and the stator windings 13u, 13v, and 13w.
a potential difference signal VM representing a potential difference from the neutral point voltage VN
N (see (E) in FIG. 11) is detected and the potential difference signal VMN is integrated by the integrator 16 to obtain an integrated signal {VMNd}.
t {see (F) in FIG. 11} is output. The integration signal ∫VMNdt has a substantially sinusoidal waveform having a frequency three times the rotation frequency. The integrated signal {VMNdt} is full-wave rectified in the level detection circuit 17 (see (G) in FIG. 11). After the full-wave rectified signal is smoothed, a smoothed signal {(H) in FIG. 11] The reference｝ and the reference value E3 are compared by the comparator 17j, and the level detection signal ｛(I) in FIG.
Reference｝ is output. That is, when the level of the smoothed signal is equal to or less than the reference value E3, the level detection signal is set to the H level, and when the level of the smoothed signal exceeds the reference value E3, the level detection signal is set to the L level.

The microprocessor 18 has a phase correction timer 18a to which a rotation position detection signal output from the rotation position detection circuit 20 is connected via an external interrupt terminal, and a stator winding 13u which receives the rotation position detection signal as an input. , 13v, 1
Period measurement timer 1 for measuring the period of 3w voltage pattern
8b and the timer value measured from the period measurement timer 18b, and the stator windings 13u, 13u
The position signal period calculator 19b that calculates the period of the voltage pattern of v, 13w and outputs a period signal representing the period, receives the period signal from the position signal period calculator 19b, and converts the period into a phase correction angle. A timer value calculating unit 19a that calculates a corresponding timer value and supplies a timer value setting signal to the phase correction timer 18a. Further, the microprocessor 18 receives an interrupt signal (see interrupt processing 2) from the phase correction timer 18a and outputs a voltage pattern signal to the inverter mode selector 19c, and a periodic signal from the position signal cycle calculator 19b. Receiving the current speed signal from the speed calculating unit 19e and an external speed command signal to output a voltage command signal. Control unit 19
f, a potential difference signal level determination unit 18c that receives the rotation position signal from the rotation position detection circuit 20 and the level detection signal from the level detection circuit 17 and outputs a phase correction angle command signal to the timer value calculation unit 19a; It has a PWM (pulse width modulation) unit 18d that receives a voltage pattern signal from the inverter mode selection unit 19c and a voltage command signal from the speed control unit 19f and outputs a switching signal.

FIGS. 12 to 14 are flow charts for explaining the interruption processing based on the rotational position detection signal (see interruption processing 1), and FIG. 15 is a flow chart for explaining the interruption processing 2. When the rotation position detection signal is supplied to the microprocessor 18, it is determined in step SP1 whether the phase correction timer 18a is counting. That is, it is determined whether or not the phase correction timer 18a started last time is counting when the interrupt processing 1 based on the rotational position detection signal occurs. If it is determined that counting is in progress, the phase correction timer 18a is stopped in preparation for the next start in step SP2, and a voltage pattern is output in step SP3.

In step SP1, the phase correction timer 1
If it is determined that 8a is not being counted, or if the processing of step SP3 has been performed, step SP4
It is determined whether or not the level detection signal is at the L level. If it is at the L level, step SP
In 5, the previous phase correction angle command is increased by 1 deg (the phase correction angle command is changed to the delay correction side), and conversely, L
If it is determined that the level is not the level, the previous phase correction angle command is decreased by 1 deg in step SP6 (the phase correction angle command is changed to the advance correction side).

After the processing in step SP5 or step SP6, it is determined in step SP7 whether the phase correction angle exceeds 60 deg. Phase correction angle is 6
If it is determined that it exceeds 0 deg, step SP
At 8, it is determined whether the phase correction angle exceeds 120 deg. If it is determined that the phase correction angle exceeds 120 deg, the phase correction is made E (denoted as E in the figure) in step SP9, and the previous phase correction C (denoted as C in the figure) is made in step SP10. ),
It is determined whether any one of the phase corrections D (denoted as correction D in the figure). Then, phase correction C and phase correction D
If it is determined to be one of
At 1, a correction switching request is made.

If it is determined in step SP8 that the angle is equal to or less than 120 deg, the phase is corrected to D in step SP12, and it is determined in step SP13 whether the previous time is either the phase correction C or the phase correction E. If it is determined that the current state is one of the phase correction C and the phase correction E, a correction switching request is made in step SP14. If it is determined in step SP7 that the angle is equal to or less than 60 deg, the phase is determined to be phase correction C in step SP15, and it is determined in step SP16 whether the previous time is either the phase correction D or the phase correction E. If it is determined that the current state is either the phase correction D or the phase correction E, a correction switching request is made in step SP17.

If any one of steps SP11, SP14, and SP17 is performed, and if it is determined in step SP10 that the previous time is neither the phase correction C nor the phase correction D, in step SP13, the previous time is the phase correction. If it is determined that none of the correction C and the phase correction E,
If it is determined in step SP16 that the previous time is neither the phase correction D nor the phase correction E, the timer value TISOU is calculated for each of the phase corrections C, D, and E in step SP18. That is, in the phase correction C, the timer value TISO
In U, a timer value corresponding to the phase correction angle is set. In phase correction D, the timer value TISOU is set to 60 de.
A timer value corresponding to the phase angle obtained by subtracting g is set, and in the phase correction E, the timer value TISOU is set to 12
A timer value corresponding to the phase angle obtained by subtracting 0 deg is set.

Thereafter, in step SP19, the inverter mode is advanced by one step. And step SP
At 20, it is determined whether there is a correction switching request. If it is determined that there is a correction switching request, it is determined in step SP21 whether the correction switching is any of the phase correction C to the phase correction D and the phase correction D to the phase correction E. If it is determined that the correction switching is one of the phase correction C to the phase correction D and the phase correction D to the phase correction E, the correction switching request is canceled in step SP22, and the process proceeds to step S22.
In P23, the inverter mode is returned by one step.

If it is determined in step SP21 that the correction switching is one of phase correction D to phase correction C and phase correction E to phase correction D, a voltage pattern is output in step SP24, and in step SP25, The timer value calculated in step SP18 is set in the phase correction timer 18a, and in step SP26, the phase correction timer 18a is started.
Release the correction switching request.

If it is determined in step SP20 that there is no correction switching request, the timer value calculated in step SP18 is set in the phase correction timer 18a in step SP28, and the phase correction timer 18a is started in step SP29. . Step SP2
3. If the processing of steps SP27 and SP29 has been performed, the value of the period measurement timer 18b is read in step SP30, the period measurement timer 18b is set and started in step SP31, and the position period calculation unit is started in step SP32. The position signal period calculation is performed by the value of the period measurement timer 18b by 19b, and the current rotation speed of the brushless DC motor is calculated by the speed calculation unit 19e from the result. Next, step SP33
In, the speed control unit 19f performs speed control based on an external speed command signal, outputs a voltage command, and returns to the original processing.

As shown in FIG. 15, when the count of the phase correction timer 18a is completed,
When an interrupt signal is output from, interrupt processing 2 starts,
In step SP1, a voltage pattern corresponding to the inverter mode determined in the interrupt processing 1 is output, and the processing returns to the original processing. Thus, the phase correction C performs a phase correction of 0 to 60 deg, the phase correction D performs a phase correction of 60 to 120 deg, and the phase correction E performs a phase correction of 120 to 180 deg.

FIG. 16 is a flowchart for explaining the processing of the command frequency control section 200. In step SP1, the previous command frequency fc0, the previous pressure load torque of the compressor (hereinafter simply referred to as load torque) Tp, the new command frequency fc1, the current frequency fp, the required frequency fr,
The current phase correction angle θ, the current load torque Tc, and the limit load (torque having a certain margin with respect to the true limit load of the compressor system) Tl are read, and step SP2 is performed.
Table of phase-torque (for example, see Table 1)
And in step SP3, the current load torque Tc is calculated from the current phase correction angle θ with reference to the phase-torque table. In step SP4, it is determined whether the current load torque Tc exceeds the limit load Tl. judge. Here, there is a relationship as shown in FIG. 17 between the output of the brushless DC motor, the operating rotation speed, and the phase, and these relationships can be stored in a table. By referring to the current phase correction angle θ, the current load torque can be calculated.

[0037]

[Table 1] If the current load torque Tc does not exceed the limit load Tl, the required frequency fr is set to the new command frequency fc1 in step SP5, and the new command frequency fc1 is set to the previous command frequency fc0 in step SP6.
At the same time, the current load torque Tc is set as the previous load torque Tp, and the process returns to the original processing.

If it is determined in step SP4 that the current load torque Tc exceeds the limit load Tl, then in step SP7, a value obtained by subtracting the previous load torque Tp from the current load torque Tc is a predetermined value ( For example, it is determined whether it exceeds 5 kg / cm ² ). If it does not exceed the predetermined value, a value obtained by subtracting 2 from the current frequency fp is set as a new command frequency fc1 in step SP8 (the drooping control shown in FIG. 18A is performed) and a new command frequency is set in step SP9. Frequency fc1
Is set to the previous command frequency fc0, the current load torque Tc is set to the previous load torque Tp, and the process returns to the original processing.

On the other hand, if it is determined in step SP7 that the value obtained by subtracting the previous load torque Tp from the current load torque Tc exceeds a predetermined value, the process proceeds to step SP7.
In FIG. 18, the new operating frequency fc1 is set to 0 {FIG.
As shown in the middle (B), control is performed to stop the rotation of the brushless DC motor. In step SP11, the new command frequency fc1 is set to the previous command frequency fc0, and the current load torque Tc is changed to the previous load torque Tp.
And returns to the original processing.

As is apparent from the above description, the load torque is not detected based on the electric signal output from the thermistor but is detected based on the phase correction angle. The compressor can be driven stably without time delay and accurately detecting whether or not it exceeds the load range without improving the output limit and the strength limit of the component parts. FIG. 19 is an electric circuit diagram showing another example of the level detection circuit.

The level detection circuit 117 outputs the integrated signal ∫
An amplifier 117a whose VMNdt is supplied to an inverting input terminal
Is connected to ground GN via a resistor 117b.
D and a resistor 117c connected between the output terminal of the amplifier 117a and the non-inverting input terminal to form a hysteresis comparator having hysteresis characteristics. Therefore, as shown in (E) and (G) in FIG. 21, when the integrated signal ∫VMNdt exceeds the reference value E7, the output terminal of the amplifier 117a becomes L level, and when the integrated signal ∫VMNdt becomes less than the reference value E8, The output terminal of 117a goes high. As a result, whether or not the integration signal ΔVMNdt is equal to or higher than a predetermined level can be detected based on whether or not the level detection signal is continuous at a predetermined cycle.

FIG. 20 is a block diagram showing another example of the microprocessor 18. This microprocessor 18
Is different from the microprocessor 18 in that a read timer 18e that operates in response to the rotational position detection signal is provided, and when the read timer 18e counts over, the potential difference signal level determination unit 18c receives an interrupt signal for reading. (See interrupt processing 3). Therefore, in this case, every time the reading timer 18e started by the rotational position detection signal {see (D) in FIG. 21} counts over, as shown in (F) in FIG. Signal (shown as a read signal in the figure) is output,
Each time this interrupt signal is output, the level detection signal shown in FIG. 21 (G) is taken into the potential difference signal level determination section 18c.

FIGS. 22 to 24 are flow charts for explaining the interruption processing based on the rotational position detection signal (see interruption processing 1), and FIG. 25 is a flow chart for explaining the interruption processing 3. The flowcharts of FIGS. 22 to 24 are different from the flowcharts of FIGS. 12 to 14 in that the following determinations are performed instead of the determinations and processes of steps SP4 to SP6 in FIG.
The only difference is that processing is performed.

That is, at step SP4a, it is determined whether or not the previous level detection signal is at the H level. If it is determined that the level detection signal is at the H level, it is determined at step SP4b whether or not the current level detection signal is at the L level. judge.
If it is determined that the level is L level, the counter CNT1 is incremented by 1 in step SP4c. If it is determined that the current level detection signal is not L level, the process of step SP4f is performed.

If it is determined in step SP4a that the previous level detection signal is not at the H level, it is determined in step SP4d whether the current level detection signal is at the H level. When it is determined that the level is H level, the counter CNT1 is incremented by 1 in step SP4e. On the other hand, when it is determined that the current level detection signal is not H level, the process of step SP4f is performed as it is.

In step SP4f, the counter CNT
2 is incremented by 1 and the counter CNT is determined in step SP4g.
It is determined whether or not 2 is 2. If it is determined that it is 2, it is determined whether or not the counter CNT1 is 2 in step SP4h. And the counter CNT1
Is 2 in step SP4i, 1 deg is added to the previous phase correction angle command (delay correction side). Conversely, if it is determined in step SP4h that the counter CNT1 is not 2, the process proceeds to step S4.
At P4j, it is determined whether or not the counter CNT1 is 0. When it is determined that the counter CNT1 is 0, 1 deg is subtracted from the previous phase correction angle command (advance correction side) in step SP4k. Conversely, if it is determined in step SP4j that the counter CNT1 is not 0, the process proceeds to step SP4i and step SP4k.
Is performed, the counter CNT1 is cleared in step SP41, and the counter CNT2 is cleared in step SP4m.

If it is determined in step SP4g that the counter CNT2 is not 2, the flow advances to step SP4g.
When the processing of 4 m has been performed, the same determination and processing as in step SP7 and subsequent steps in the flowchart are performed. Since the interrupt processing 2 is the same as that in FIG. 15, illustration and description are omitted. As shown in FIG. 25, the interrupt processing 3 is performed in step SP
In step 1, the level detection signal is read, and the process returns to the original processing.

Therefore, in the case of this example, the configuration of the level detection circuit 17 can be simplified, and the same operation as in the above example can be achieved. FIG. 26 is an electric circuit diagram showing still another example of the brushless DC motor driving device, and FIG. 27 is a block diagram showing the configuration of the microprocessor. FIG. 26 differs from FIG.
1, the AC power supply 11a is connected to the diode bridge 11
b, the coil 11c and the capacitor 1
1d, a DC power source is obtained by smoothing, and one end of an AC power source 11a and a diode bridge 11b
And a current level detector 11f that detects an input current by a current sensor 11e provided between the microprocessor and the detected input current and outputs a current detection signal to the microprocessor 18 in response to the detected input current. is there.

FIG. 27 differs from FIG. 9 in that a step-out prediction level determining section 18f which outputs a signal representing a level determination result by inputting a rotational position detection signal and a level detection signal instead of the potential difference signal level determining section 18c. A motor maximum efficiency control unit 18g that receives a level determination result from the step-out prediction level determination unit 18f and a current detection signal from the current level detector 11f and supplies a phase correction angle command signal to the timer value calculation unit 19a; Is the only point provided.

FIG. 29 is a flow chart for explaining a part of the interrupt processing based on the rotational position detection signal (see interrupt processing 1). After the processing of the flowchart of FIG. 29 is performed, step S of the flowchart shown in FIGS.
Although the processing after P7 is performed, illustration of this part is omitted in FIG. In step SP1, upon receiving the current detection signal from the current level detector 11f, the motor efficiency maximum control unit 18g sets the current value of the input current input to the inverter 12 as the current current value.

In step SP2, it is determined whether or not the previous phase correction angle command is advance correction. If advance correction is performed, in step SP3, whether the previous current value exceeds the current current value is determined. Determine whether or not. If it has exceeded, in step SP4, the previous phase correction angle command is set to -1 deg (advance correction side). Conversely, if it is determined in step SP3 that the previous current value has not exceeded the current value, it is determined in step SP5 whether the level detection signal is at the L level.
If it is at the L level, the previous phase correction angle command is incremented by +1 deg (delay correction side) in step SP6, whereas if it is not at L level, the previous phase correction angle command is decremented by -1 deg (lead correction side) in step SP7 ).

If it is determined in step SP2 that the previous phase correction angle command has not been advanced and corrected, it is determined in step SP8 whether the previous current value has exceeded the current current value. If not, the previous phase correction angle command is set to -1 de in step SP12.
g (advance correction side). Conversely, when it is determined in step SP8 that the previous current value exceeds the current current value, the level detection signal is set to L in step SP9.
It is determined whether or not the current phase is the L level. If the level is the L level, the previous phase correction angle command is incremented by +1 deg (delay correction side) in step SP10. The correction angle command is set to -1 deg (advance correction side).

After any of the processing of step SP4, step SP6, step SP7, step SP10, step SP11, and step SP12 is performed, the current value is set to the previous current value in step SP13. Therefore, every time the interrupt processing 1 is performed, the previous current value is compared with the current current value to detect an increase or decrease in the input current of the inverter 12. I do. Then, as shown in FIG. 28, the input current is minimized by advancing the phase correction angle command with a delay of 1 deg in accordance with the increase or decrease of the input current. Thereby, the motor efficiency is almost maximized.

FIG. 30 is a block diagram showing another example of the rotational position detecting unit.
Rotary encoder 113 connected to rotary shaft 3a
An interface 114 is provided for receiving a signal indicating the rotational position from and outputting a position signal. Therefore,
Also in this case, the position of the rotor can be accurately detected, and the drive control of the brushless DC motor can be achieved similarly to the above-described examples.

When the compressor of the air conditioner is employed as the compressor according to any of the above embodiments, the comfort of the air conditioner can be improved by the stable driving of the compressor. .

[0056]

According to the first aspect of the present invention, the detection of whether or not the load exceeds the load range can be accurately and accurately achieved without improving the output limit and the strength limit of the component parts.
This has a specific effect that the compressor can be driven stably, and further, reliability can be secured and cost can be reduced.

According to the second aspect of the present invention, the detection of whether or not the load exceeds the load range can be accurately and without delay, without improving the output limit and the strength limit of the component parts, thereby stabilizing the compressor. , And a unique effect that reliability can be ensured and cost reduction can be achieved. According to the third aspect of the present invention, the detection of whether or not the load exceeds the load range can be accurately and without delay, and the compressor can be driven stably without improving the output limit and the strength limit of the component parts. This has a specific effect that reliability and cost reduction can be achieved.

According to the fourth aspect of the present invention, the detection of whether or not the load exceeds the load range can be accurately and without delay, without improving the output limit and the strength limit of the component parts. In this case, the brushless DC motor is reliably stopped to ensure reliability, and a unique effect is obtained. The invention of claim 5 does not improve the limit of output and the strength limit of component parts,
Detection of whether or not the load exceeds the load range can be accurately performed without time delay. Based on the detection result, the brushless DC motor can be driven so that the output does not exceed the limit load, and rapid compression can be performed. When the output may exceed the limit load due to load fluctuation, the brushless DC motor can be surely stopped, and as a result, it is possible to secure reliability and achieve cost reduction.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a operable load range and a rotation speed.

FIG. 2 is a diagram illustrating overload control according to a conventional method.

FIG. 3 is a diagram showing a conventional method in which a margin for ensuring reliability is set.

FIG. 4 is a block diagram showing one embodiment of a compressor driving device of the present invention.

FIG. 5 is a schematic diagram showing one embodiment of a brushless DC motor drive control device of the present invention.

FIG. 6 is a diagram schematically showing a configuration of a brushless DC motor having a surface magnet structure.

FIG. 7 is a diagram schematically showing a configuration of a brushless DC motor having an embedded magnet structure.

FIG. 8 is a diagram schematically illustrating an example of a configuration of a brushless DC motor drive control device.

9 is a diagram showing an internal configuration of the microprocessor of FIG.

FIG. 10 is an electric circuit diagram showing a level detection circuit.

FIG. 11 is a diagram showing signal waveforms at various parts of the brushless DC motor drive control device of FIG. 8;

FIG. 12 is a flowchart illustrating in detail a part of processing contents of interrupt processing 1 of FIG. 9;

13 is a flowchart describing in detail another part of the processing contents of the interrupt processing 1 of FIG. 9;

FIG. 14 is a flowchart describing in detail the processing contents of the remaining part of the interrupt processing 1 of FIG. 9;

FIG. 15 is a flowchart illustrating processing contents of interrupt processing 2 in FIG. 9;

FIG. 16 is a flowchart illustrating details of the processing content of a command frequency determination unit in FIG. 4;

FIG. 17 is a diagram showing a relationship among a motor output, an operation frequency, and a phase.

FIG. 18 is a diagram illustrating rotation speed control according to the present invention.

FIG. 19 is an electric circuit diagram showing another example of the level detection circuit.

FIG. 20 shows a brushless DC motor drive control device.
FIG. 2 is a diagram illustrating an internal configuration of a microprocessor.

FIG. 21 is a diagram showing signal waveforms at various parts of the brushless DC motor drive control device including the configuration of FIG. 20;

FIG. 22 is a flowchart illustrating in detail a part of processing contents of interrupt processing 1 of FIG. 20;

FIG. 23 is a flowchart illustrating details of another part of the interrupt processing 1 of FIG. 20;

FIG. 24 is a flowchart describing in detail the processing contents of the remaining part of interrupt processing 1 of FIG. 20;

FIG. 25 is a flowchart illustrating processing contents of interrupt processing 3 of FIG. 20;

FIG. 26 is a drawing schematically showing another example of the configuration of the brushless DC motor drive control device.

FIG. 27 is a diagram showing an internal configuration of the microprocessor of FIG. 26;

FIG. 28 is a diagram illustrating motor efficiency maximum control that minimizes input current.

FIG. 29 is a flowchart illustrating in detail a part of processing contents of interrupt processing 1 of FIG. 27;

FIG. 30 is a circuit diagram of a rotational position detector using a rotary encoder.

[Explanation of symbols]

2,12 Inverter 3,13 Brushless DC motor 6 Compressor 13a Rotor 18 Microprocessor 18a Phase correction timer 20 Rotational position detection circuit

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Tanaka 1000-2 Oya, Okamoto-cho, Kusatsu-shi, Shiga Daikin Industries, Ltd. Shiga Works (58) Field surveyed (Int. Cl. ⁷ , DB name) H02P 6/02

Claims (5)

(57) [Claims] When a compressor (6) is driven by a brushless DC motor (3) (13) controlled by an inverter (2) (12), a rotor of the brushless DC motor (3) (13) is used. (13
a) is detected, and the rotor (13) of the brushless DC motor (3) (13) is detected.
a) setting a phase correction angle of the electric signal output from the inverter with respect to the position of a), and responding to the commanded rotational speed and the detected rotational position of the rotor, the necessary brushless DC motors (3) and (13) A compressor driving method for supplying a control signal to an inverter (2) (12) to obtain an output and a rotation speed, based on a phase correction angle of an electric signal output from the inverter with respect to a position of a rotor (13a). Detect compression load,
A compressor driving method comprising: supplying a control signal to the inverters (2) and (12) based on a detected compression load so as not to exceed a limit load of the compressor system. 2. A compressor driving device for driving a compressor (6) by a brushless DC motor (3) (13) controlled by an inverter (2) (12), wherein the brushless DC motor (3) (13) Rotor (13
Rotational position detecting means (20) for detecting the rotational position of a)
And the rotor (13) of the brushless DC motor (3) (13).
phase correction angle setting means (18a) for setting the phase correction angle of the electric signal output from the inverter with respect to the position of a)
And a required brushless DC motor (3) (1) in response to the command rotation speed and the detected rotational position of the rotor (13a).
Inverter (2) to obtain output and speed of 3)
Inverter control means (1) for supplying a control signal to (12)
8) a compressor drive device comprising: a compressor load detecting means for detecting a compression load based on a phase correction angle of an electric signal output from the inverter with respect to a position of the rotor (13a); Means (18) for controlling the inverter (2) (1) so as not to exceed the limit load of the compressor system based on the detected compression load;
2. A compressor driving device for supplying a control signal to 2). 3. The brushless DC motors (3) and (13) are driven by the brushless DC motors (3) and (13) when driven by the brushless DC motors (3) and (13) controlled by the inverters (2) and (12). (13
a) is detected, and the rotor (13) of the brushless DC motor (3) (13) is detected.
a) setting a phase correction angle of the electric signal output from the inverter with respect to the position of a), and responding to the commanded rotational speed and the detected rotational position of the rotor (13a), and a necessary brushless DC motor (3) ( 1
Inverter (2) to obtain output and speed of 3)
A compressor driving method for supplying a control signal to (12), comprising detecting a compression load based on a phase correction angle of an electric signal output from an inverter with respect to a position of a rotor (13a),
Based on the detected compression load, the brushless DC motor (3) (1) is controlled so as not to exceed the limit load of the compressor system.
A compressor driving method characterized in that a control signal is supplied to the inverters (2) and (12) to control the number of revolutions of 3). 4. When the compressor (6) is driven by the brushless DC motors (3) and (13) controlled by the inverters (2) and (12), rotors of the brushless DC motors (3) and (13). (13
a) is detected, and the rotor (13) of the brushless DC motor (3) (13) is detected.
a) setting a phase correction angle of the electric signal output from the inverter with respect to the position of a), and responding to the commanded rotational speed and the detected rotational position of the rotor (13a), and a necessary brushless DC motor (3) ( 1
Inverter (2) to obtain output and speed of 3)
A compressor driving method for supplying a control signal to (12), comprising detecting a compression load based on a phase correction angle of an electric signal output from an inverter with respect to a position of a rotor (13a),
Based on the detected compression load, it is detected that the critical load of the compressor system is exceeded, and in response to detecting that the critical load of the compressor system is exceeded, the brushless DC
A method for driving a compressor, comprising supplying a control signal to inverters (2) and (12) to stop motors (3) and (13). 5. A rotor of a brushless DC motor (3) (13) for driving a compressor (6) by a brushless DC motor (3) (13) controlled by an inverter (2) (12). (13
a) is detected, and the rotor (13) of the brushless DC motor (3) (13) is detected.
a) setting a phase correction angle of the electric signal output from the inverter with respect to the position of a), and responding to the commanded rotational speed and the detected rotational position of the rotor (13a), and a necessary brushless DC motor (3) ( 1
Inverter (2) to obtain output and speed of 3)
A compressor driving method for supplying a control signal to (12), comprising detecting a compression load based on a phase correction angle of an electric signal output from an inverter with respect to a position of a rotor (13a),
Based on the detected compression load, the brushless DC motor (3) (1) is controlled so as not to exceed the limit load of the compressor system.
A control signal is supplied to the inverters (2) and (12) to control the rotation speed of 3), and a sudden change in the compression load that may exceed the limit load of the compressor system based on the detected compression load. And the inverters (2) and (12) are controlled to stop the brushless DC motors (3) and (13) in response to detecting that the sudden change in the compression load has occurred. A method for driving a compressor, comprising supplying a signal.