JPH09238493A - Brushless dc motor driving control equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent step-out and enable operation with desired efficiency. SOLUTION: A potential difference signal is detected which indicates the potential difference between the neutral point of armature coils 1a, 1b, 1c and the neutral point of a three-phase Y-connected resistor circuit 2 in the parallel state to the armature coils 1a, 1b, 1c. The potential difference signal is integrated with an integrator 22. On the basis of the integrated signal, the rotation position of the armature 1 is detected. Whether the level of the integrated signal is higher than or equal to a target value obtained by smoothing a PWM signal having a desired duty ratio is detected with a level detector 6. On the basis of the rotation position, a voltage pattern is changed over. On the basis of the detected result, the time to elapse until the voltage pattern is changed over from a position signal is adjusted by a correcting means, in such a manner that the level of the integrated signal becomes a target value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless DC motor drive controller, and more specifically, it relates to a relative position between a rotor and a stator based on an induced voltage induced in an armature coil of a brushless DC motor. The present invention relates to a brushless DC motor drive control device that detects a position signal representing a different position and controls the voltage pattern of an armature coil based on the position signal.

[0002]

2. Description of the Related Art Conventionally, as a brushless DC motor drive control device, there is one described in Japanese Patent Publication No. 5-72197. This brushless DC motor drive control device, as shown in FIG. 16, has a rotor 7 having permanent magnets with a plurality of poles.
0 and armature coils 71a, 71b connected in three-phase Y
Stator 71 having 71c, and the armature coil 71
a, 71b, 71c, a resistor circuit 72 including resistors 72a, 72b, 72c connected in three phases in a Y state in parallel, and a rotor 7 for the armature coils 71a, 71b, 71c.
Rotational position detector 73 for detecting the relative rotational position of 0
And a position signal indicating the rotational position of the rotor 70 from the rotational position detector 73, and the armature coils 71a, 71
Microcomputer (hereinafter, abbreviated as a microcomputer) 74 for switching voltage patterns for b and 71c, and commutation control for switching control of voltage patterns of armature coils 71a, 71b, 71c in response to a switching signal from the microcomputer 74. Base drive circuit 7 that outputs a signal
5 and an inverter section 80 that receives a commutation control signal from the base drive circuit 75 and switches the voltage pattern of the armature coils 71a, 71b, 71c.

The inverter section 80 includes three transistors 80a, 80b and 80c, which are respectively connected to the positive side of the DC power source 76 via a switch 77, and the DC power source 7.
3 transistors 8 connected to the negative side of 6 respectively
0d, 80e, 80f. The collectors of the transistors 80a and 80d are connected to each other, the collectors of the transistors 80b and 80e are connected to each other, and the collectors of the transistors 80c and 80f are connected to each other. The U-phase armature coil 71a is connected to the mutually connected portions of the transistors 80a and 80d, and the V-phase armature coil 71b is connected to the mutually connected portions of the transistors 80b and 80e. The W-phase armature coil 71c is connected to the mutually connected portions of 80f. Then, the commutation control signal from the base drive circuit 75 is input to the bases of the transistors 80a to 80f.

The rotational position detector 73 includes a voltage VM at a neutral point of the resistance circuit 72 and armature coils 71a, 71.
The voltage VN at the neutral point of b and 71c is input, and the neutral point of the resistor circuit 72 and the armature coils 71a, 71b and 7 are input.
A differential amplifier 81 that outputs a potential difference signal VMN representing a potential difference from the neutral point of 1c; an integrator 82 that receives the potential difference signal VMN from the differential amplifier 81 and integrates the potential difference signal VMN; Potential difference signal VM from the device 82
It has a zero-cross comparator 83 which receives an integrated signal obtained by integrating N and outputs a position signal. Further, both ends of the armature coil 71c are respectively connected to input terminals of the comparator 84, and the comparator 84 outputs a signal indicating the polarity of the induced voltage EW to the microcomputer 74.

In the brushless DC motor drive controller having the above structure, each U phase, V phase, and
When the W-phase motor terminal voltage is VU, VV, VW, and the U-phase, V-phase, and W-phase induced voltages of the armature coils 71a, 71b, 71c are EU, EV, EW, the neutral point of the resistance circuit 72 Of the voltage VM and the voltage VN at the neutral point of the armature coils 71a, 71b, 71c are VM = (1/3) (VU + VV + VW) VN = (1/3) {(VU-EU) + (VV-EV) ) +
(VW-EW)}. Therefore, the potential difference signal VMN representing the potential difference between the neutral point of the resistor circuit 72 and the neutral point of the armature coils 71a, 71b, 71c is VMN = VM-VN = (1/3) (EU + EV + EW) The induced voltage of the child coils 71a, 71b, 71c is proportional to the sum of EU, EV, EW.

The armature coils 71a, 71b, 71c
The induced voltages EU, EV, and EW are trapezoidal waveforms having different phases every 120 deg, and the potential difference signal VMN is
The induced voltage becomes a substantially triangular wave having a fundamental wave frequency component that is three times that of EU, EV, and EW. This potential difference signal VMN
The peak point of the triangular wave becomes the switching point of the voltage pattern. The integrator 82 integrates the potential difference signal VMN from the differential amplifier 81 to generate a substantially sinusoidal integrated signal ∫VMNd.
Output t. Then, the zero-cross comparator 8
3 detects a zero-cross point of the integrated signal ∫VMNdt and outputs a position signal to the microcomputer 74. That is, since the amplitude of the peak point of the potential difference signal VMN varies depending on the rotation speed, the potential difference signal VMN is integrated to detect the zero cross point. The position signals correspond to the armature coils 71a, 71a of the stator 71.
It shows the relative position of the rotor 70 with respect to b and 71c. Next, the microcomputer 74 receives the position signal from the zero-cross comparator 83 and outputs a switching signal to the base drive circuit 75. The base driving circuit 75 receives the switching signal from the microcomputer 74 and receives the switching signals from the transistors 80a to 8a of the inverter unit 80.
The commutation control signal is output to the base of 0f. Then, the transistors 80a to 80f of the inverter unit 80 are sequentially turned on and off to generate the armature coils 71a, 71b, 71c.
Switch the voltage pattern for.

Thus, the brushless DC motor is
Let E be the induced voltage of the armature coils 71a, 71b, 71c.
A position signal indicating the rotational position of the rotor 70 is output from U, EV, EW, and the inverter unit 80 switches the voltage pattern of the armature coils 71a, 71b, 71c according to the position signal.

[0008]

By the way, when a brushless DC motor driven and controlled by the brushless DC motor drive control device is used to drive a load such as a compressor having a large fluctuation range of torque, a brushless DC motor is used. If the performance of 1 is sufficiently exhibited, the compressor can be operated within the operation area (see FIG. 17) required for the compressor. However, in the brushless DC motor drive control device, the higher the operating frequency, the larger the load and the larger the motor current, the more difficult it becomes to detect the position of the rotor.
Since the performance of the C motor cannot be fully exhibited, there is a problem that the motor cannot be operated at maximum efficiency. Moreover, if it becomes difficult to detect the position of the rotor, in the worst case, there is a problem that the motor loses step due to insufficient torque. Of course, it becomes difficult to operate the motor with desired efficiency.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a brushless DC motor drive controller capable of preventing step-out and operating at a desired efficiency.

[0010]

A brushless D according to claim 1
The C motor drive control device includes a rotor having a magnet with a plurality of poles, a stator having an armature coil connected to a three-phase Y connection, and a three-phase Y connection in parallel with the armature coil. A resistance circuit, a potential difference signal representing a potential difference between the neutral point of the armature coil and the neutral point of the resistance circuit is detected,
Rotational position detection means for detecting a relative rotational position of the rotor and the stator based on the potential difference signal and outputting a position signal whose level is switched according to the rotational position, and the rotational position detection means. Based on the position signal of the means,
In a brushless DC motor drive control device including an inverter unit that switches a voltage pattern of the armature coil, the level of the signal is equal to or higher than a target value upon receiving the potential difference signal or an integrated signal obtained by integrating the potential difference signal. Based on the determination result of the level determination means, the level determination means for determining whether or not the target value given to the level determination means is variable, and the level of the signal is set to the target value. And a control means for controlling the switching of the voltage pattern.

In the brushless DC motor drive controller according to a second aspect of the present invention, as the control means, the level of the potential difference signal or an integrated signal obtained by integrating the potential difference signal based on the determination result of the level determination means is the target. The one that adjusts the time from the position signal until the voltage pattern is switched or the voltage is adjusted so that the value becomes a value is adopted.

According to another aspect of the brushless DC motor drive control device of the present invention, the target value setting means includes pulse width modulating means, duty ratio setting means for setting the duty ratio of the pulse width modulating means, and output from the pulse width modulating means. And a smoothing means for smoothing the pulse signal to be output as a target value. Brushless D according to claim 4.
The C motor drive control device, as the target value setting means,
Pulse width modulation means, duty ratio setting means for setting the duty ratio of the pulse width modulation means, and D / A conversion means for converting the pulse signal output from the pulse width modulation means into an analog signal and outputting it as a target value. The one that includes is adopted.

In the brushless DC motor drive control device according to a fifth aspect of the present invention, the target value setting means sets a target value corresponding to the operating conditions of the brushless DC motor.

[0014]

According to the brushless DC motor drive control device of the present invention, the rotational position detecting means detects a potential difference signal representing a potential difference between the neutral point of the armature coil and the neutral point of the resistance circuit. At the same time, based on the potential difference signal, the relative rotational position between the rotor having a magnet having a plurality of poles and the stator is detected, and a position signal whose level is switched according to the rotational position is output. Then, the target value setting means variably sets the target value, and the level determination means determines whether the level of the potential difference signal or the integrated signal obtained by integrating the potential difference signal is equal to or higher than the target value. Based on the result of this determination, the control means controls the switching of the voltage pattern so that the level of the signal becomes the target value.

Therefore, by setting the target value for determining the level of the potential difference signal or the integrated signal to the level of the signal at the desired efficiency, the brushless DC motor can be operated at the desired efficiency. Moreover, by setting the target value to the signal level at the time of maximum efficiency, the brushless DC motor can be accurately operated at maximum efficiency.

According to another aspect of the brushless DC motor drive control device of the present invention, the level of the potential difference signal or the integrated signal obtained by integrating the potential difference signal based on the determination result of the level determination means is determined by the control means. The time until the voltage pattern is switched from the position signal to the target value is adjusted, or the voltage is adjusted. Then, the inverter switches the voltage pattern of the armature coil based on the phase-corrected voltage pattern signal or the voltage-adjusted voltage pattern signal from the control means.

Therefore, it is possible to achieve the same effect as that of claim 1. In the brushless DC motor drive control device according to claim 3, the target value setting means outputs from the pulse width modulating means, the duty ratio setting means for setting the duty ratio of the pulse width modulating means, and the pulse width modulating means. The target value can be easily changed by changing the duty ratio because the smoothing means for smoothing the pulse signal to be outputted as the target value is adopted. As a result, the target value can be changed. Alternatively, the same effect as that of claim 2 can be achieved. Of course, the configuration can be simplified and cost reduction can be achieved as compared with the case where a plurality of level determination means are provided so that a plurality of target values can be selectively adopted in advance.

According to another aspect of the brushless DC motor drive control device of the present invention, the target value setting means includes a pulse width modulating means, a duty ratio setting means for setting a duty ratio of the pulse width modulating means, and a pulse width modulating means. The target value can be easily changed by changing the duty ratio, since the pulse signal output from the D / A converting means for converting the pulse signal to the analog signal and outputting it as the target value is adopted. As a result, the same operation as that of claim 1 or claim 2 can be achieved. Of course, the configuration can be simplified and cost reduction can be achieved as compared with the case where a plurality of level determination means are provided so that a plurality of target values can be selectively adopted in advance.

In the brushless DC motor drive control device according to the present invention, since the target value setting means for setting the target value corresponding to the operating condition of the brushless DC motor is adopted, any operation can be performed. When the condition is set, the target value corresponding to this operating condition is set, and the operation can be performed at a predetermined efficiency determined based on the target value.

[0020]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of a brushless DC motor drive control device of the present invention. This brushless DC motor drive controller drives and controls a brushless DC motor including a rotor 10 having permanent magnets with a plurality of poles and a stator 1 having armature coils 1a, 1b, 1c connected in three-phase Y. It is for. The brushless DC motor drive control device includes a resistance circuit 2 including resistors 2a, 2b and 2c connected in three-phase Y in parallel with the armature coils 1a, 1b and 1c, and the armature coils 1a and 1b. , 1c, a rotational position detector 3 for detecting a relative rotational position of the rotor 10, and a position signal representing the rotational position of the rotor 10 from the rotational position detector 3 to receive an armature coil 1a,
A microcomputer (hereinafter, abbreviated as a microcomputer) 4 for switching voltage patterns for 1b and 1c, and a commutation control for receiving switching signals from the microcomputer 4 and switching control of voltage patterns of the armature coils 1a, 1b, 1c. It has a base drive circuit 5 that outputs a signal, and an inverter unit 20 that receives a commutation control signal from the base drive circuit 5 and switches the voltage pattern of the armature coils 1a, 1b, 1c.

The rotational position detector 3 inputs the neutral point voltage VM of the resistor circuit 2 to the non-inverting input terminal, and
An amplifier IC1 in which a ground GND is connected to an inverting input terminal via a resistor R3 and a resistor R2 is connected between an output terminal and an inverting input terminal, and a resistor R4 and a capacitor C1 are connected in series to an output terminal of the amplifier IC1. Integrated circuit 2
2 and an amplifier IC2 having a non-inverting input terminal connected to a connection point between the resistor R4 and the capacitor C1 of the integrating circuit 22 and an inverting input terminal connected to the ground GND.

The amplifier IC1 and the resistors R2 and R3 constitute a differential amplifier 21, and the amplifier IC2 constitutes a zero-cross comparator 24. The neutral point of the armature coils 1a, 1b, 1c is the ground GN.
Since it is connected to the non-inverting input terminal of the amplifier IC1 via D, the differential amplifier 21 has a voltage VM at the neutral point of the resistor circuit 2 and a voltage VN at the neutral point of the armature coils 1a, 1b, 1c. The potential difference signal VMN representing the potential difference between the potential difference and the potential difference is detected, the integration circuit 22 integrates the potential difference signal VMN, and outputs the integrated signal ∫VMNdt.

The brushless DC motor drive control device further includes a level detector 6 which receives the integrated signal ∫VMNdt from the integrator 22 of the rotational position detector 3 and outputs a level detection signal to the microcomputer 4. . As shown in FIG. 2, the level detector 6 connects the integrated signal ∫VMNdt from the integrator 22 of the rotational position detector 3 to the inverting input terminal of the amplifier IC4, and also connects the non-inverting input terminal of the amplifier IC4 with a resistor. It is connected to the ground GND via R8. A resistor R9 is connected between the non-inverting input terminal and the output terminal of the amplifier IC4. And the amplifier IC4
Is supplied to the microcomputer 4. The amplifier I
C4 and resistors R8 and R9 form a hysteresis comparator having a hysteresis characteristic.

Since the inverter section 20 has the same structure as the inverter section 80 shown in FIG. 16, detailed description thereof will be omitted. The microcomputer 4, as shown in FIG.
The phase correction timer T1 in which the position signal from the rotational position detector 3 shown in FIG. 1 is connected via the external interrupt terminal and the position signal are received to measure the period of the voltage pattern of the armature coils 1a, 1b, 1c. It receives the period measurement timer T2 and the measured timer value from the period measurement timer T2, calculates the period of the voltage pattern of the armature coils 1a, 1b, 1c from the timer value, and represents the period of the position signal. The position signal period calculation unit 41 that outputs a period signal and the period signal from the position signal period calculation unit 41 are received, the timer value corresponding to the phase correction angle is calculated from the period, and the phase correction timer T1
And a timer value calculator 42 that outputs a timer value setting signal. Further, the microcomputer 4 receives the interrupt signal IRQ from the phase correction timer T1 and receives an inverter mode selection unit 43 that outputs a voltage pattern signal, and a periodic signal from the position signal period calculation unit 41 to determine the rotation speed. To output a current speed signal, and a speed control section 45 that receives the current speed signal from the speed calculation section 44 and a speed command signal from the outside and outputs a voltage command signal.
And a position signal from the rotational position detector 3 and a level detection signal from the level detector 6 to output a phase correction command signal to the timer value calculator 42 and reset after reading the level detection signal. A level determination unit 51 that outputs a signal and a phase correction command signal output from the level determination unit 51 are received, and the phase is converted to torque.
A level detection signal switching unit 53 that outputs a pulse width modulation (PWM) signal having a predetermined duty ratio based on the converted torque, a voltage pattern signal from the inverter mode selection unit 43, and a voltage command signal from the speed control unit 45. In response to this, it has a PWM unit 52 which outputs a switching signal. The phase correction timer T1, the cycle measuring timer T2, the cycle calculating section 41, and the timer value calculating section 42 constitute a control means. Further, the level detector 6 and the level determination section 51 constitute a level determination means.

FIG. 4 is an electric circuit diagram showing in detail the configurations of the rotational position detector 3 and the level detector 6 connected to the microcomputer 4. When the detection level is determined by the software of the microcomputer 4, a PWM signal with a predetermined duty ratio is output from the level detection signal switching unit 53 and is supplied to the chopping transistor Q1 through the photocoupler PC1 to perform chopping. . This chopped PWM signal is PWM
It is sent to the smoothing unit 62 and smoothed, and this PWM smoothed signal becomes a target value for level detection. Then, the integrated signal ∫VMNdt output from the middle of the rotational position detector 3
And a PWM smoothing signal are supplied to the comparator CP1 and a signal indicating whether or not the integrated signal ∫VMNdt is larger than the PWM smoothing signal is output through the photocoupler PC2 and latched by the latch circuit L1. Then, the latch signal of the latch circuit L1 is taken into the microcomputer 4 as a level detection signal. After the microcomputer 4 takes in the latch signal, the microcomputer 4 supplies a reset signal to the latch circuit L1 to release the latch of the latch circuit L1. Of course, the rotational position detector 3 includes the zero cross comparator 24.
The position signal output from the microcomputer is supplied to the microcomputer 4 through the photocoupler PC3. The photo coupler P
C1, PC2 and PC3 are for ensuring insulation between the high-power part and the low-power part and for reliably transmitting only the signal.

The rotational position detector 3 of FIG. 4 has a different structure from the rotational position detector 3 of FIG. 1, but achieves the same operation. Specifically, the non-inverting input terminal of the amplifier IC4 is connected to the ground GND via the resistor R5, and the resistor R6 and the capacitor C2 are connected in parallel between the inverting input terminal and the output terminal to form a differential circuit. The amplifier 21 also serves as the integrator 22, and the non-inverting input terminal of the amplifier IC5 is connected to the resistor R.
The zero-cross comparator 24 is formed by connecting the light-emitting element of the photocoupler PC3 and the resistor R8 in series between the output terminal and the non-inverting input terminal while being connected to the ground GND via 7.

In the above structure, when the brushless DC motor is driven according to position detection, the induced voltage E of each U phase, V phase and W phase of the armature coils 1a, 1b, 1c.
As shown in FIGS. 5A to 5C, U, EV, and EW are trapezoidal waveforms having different phases for each 120 deg. Then, the amplifier IC of the rotational position detector 3 shown in FIG.
1 is the voltage VM at the neutral point of the resistor circuit 2 input to the inverting input terminal and the voltage VN at the neutral point of the armature coils 1a, 1b, 1c input to the non-inverting input terminal of the amplifier IC1. Potential difference signal VMN representing potential difference {see (D) in FIG. 5}
Is detected, the potential difference signal is integrated, and an integrated signal ∫VMNdt {see (E) in FIG. 5} is output. The integrated signal ∫VMNdt has a substantially sine waveform having a frequency three times the inverter frequency. And the integrated signal ∫VMN
The zero cross of dt is detected by the zero cross comparator 24, and the position signal {see (F) in FIG. 5} is output.

Next, the position signal from the rotational position detector 3 is sent from the external interrupt terminal of the microcomputer 4 to the cycle measuring timer T.
2 is input. Then, the period measuring timer T2 is
The period from the leading edge to the trailing edge and the period from the trailing edge to the leading edge of the position signal are measured, and the measured timer value is output. In response to the signal indicating the timer value from the cycle measuring timer T2, the cycle calculating unit 41 causes the armature coils 1a, 1
The period of the voltage pattern of b and 1c is calculated. That is, the period from the trailing edge to the leading edge and the period from the leading edge to the trailing edge of the position signal are repeated every 60 deg, and the voltage is increased by multiplying the measured timer value of each period by six. The timer value for one cycle of the pattern is calculated.

Then, in response to the periodic signal representing the period from the period computing unit 41, the timer value computing unit 42 outputs the timer value setting signal. Upon receiving the timer value setting signal from the timer value calculation unit 42, the phase correction timer T1 elapses the time until the voltage signal is switched from the position signal. That is, the phase correction timer T1 causes the inverter mode selection unit 43 to receive the interrupt signal IR when the count ends.
The inverter mode selector 43 outputs Q and the phase-corrected voltage pattern signal {see (I) to (N) in FIG. 5}.
Is output to the PWM unit 52. Then, the PWM unit 52 outputs the switching signal to the base drive circuit 5 shown in FIG. 1, and when the base drive circuit 5 outputs the commutation control signal to the inverter unit 20, the transistors 20a to 20f of the inverter unit 20 are Turn on and off respectively. The position signal numbers in (H) of FIG. 5 are numbers 0 to 5 assigned to one cycle of the position signal for ease of explanation. In addition, the inverter mode shown in (P) of FIG. 5 is numbered 0 to 5 so as to correspond to the voltage pattern signal selected by the inverter mode selection unit 43 {see (I) to (N) in FIG. 5}. It is assigned.

Next, FIG. 4, which is the most important point of the present invention,
The level detector 6 shown in will be described in more detail.
FIG. 6 is a diagram showing the relationship between the integrated signal and the phase correction angle,
6A shows the case where the load torque is large, and FIG. 6B shows the case where the load torque is small. The detection level that maximizes the efficiency is V1 when the load torque is large, and V2 when the load torque is small. Further, the relationship between the PWM duty ratio and the load torque with respect to the detection levels V1 and V2 is as shown in FIG. Furthermore, the relationship between the phase correction angle and the load torque is as shown in FIG.

Therefore, the level determination unit 5 of the microcomputer 4
When the phase amount command is output from 1, the level detection signal switching unit 53 uses these relationships to perform PWM.
The duty ratio is obtained and the PWM signal of this duty ratio is output. This PWM signal is chopped by the chopping transistor Q1 and is shown by P in FIG.
It becomes a WM signal. Then, by smoothing the PWM signal shown in FIG. 9A, a PWM smoothed signal of a voltage having a constant relationship with the duty ratio as shown in FIG. 10 (see (B) in FIG. 9) is obtained. The relationship between the PWM smoothed signal and the integrated signal ∫VMNdt is as shown in (C) of FIG. Further, a position signal which rises at the zero crossing of the integrated signal ∫VMNdt and falls at the next zero crossing (see FIG. 9).
Middle (D) reference} is obtained.

Then, when the integrated signal ∫VMNdt exceeds the PWM smoothing signal, it rises and is latched,
At the rising edge of the position signal, a level detection signal (see (F) in FIG. 9) read by the microcomputer 4 is obtained, and a low level reset signal {see (E) in FIG. 9} is read from the microcomputer 4 after reading the level detection signal. Output and latch circuit L
Release the 1 latch.

Therefore, by simply changing the duty ratio of the PWM signal, the voltage value of the PWM smoothing signal that functions as the target value can be changed. As a result, the structure can be remarkably simplified as compared with the case where a plurality of level detectors are provided. Further, the number of photocouplers and the number of input ports of the microcomputer for inputting the digital signal can be significantly reduced as compared with the case where the integrated signal is A / D converted and supplied as a digital signal to the level determination unit. Therefore, the structure can be remarkably simplified, and the cost increase of the A / D converter can be avoided. Further, the duty ratio may be D / A converted to be the target value. Further, as shown in FIG. 11, instead of the chopping transistor Q1 and the PWM smoothing unit 62 of FIG.
You may employ | adopt the structure which employ | adopts the converter 62 '. Furthermore, the target value can be finely changed by changing the duty ratio, and the brushless DC motor can be operated with desired efficiency.

Specifically, when the absolute value of the integrated signal ∫VMNdt becomes larger than that of the PWM smoothing signal, as shown in FIG.
As shown in middle (F), the output signal from the level detector 6 is inverted. In this case, the level determination unit 51 outputs a phase correction command signal to the timer value calculation unit 42 so as to adjust the phase of the inverter output voltage in the delay direction so that the integrated signal ∫VMNdt becomes smaller. On the contrary, when the absolute value of the integrated signal ∫VMNdt becomes smaller than the PWM smoothing signal, the output signal from the level detector 6 is not inverted as shown in (F) of FIG. In this case, the level determination unit 51 outputs a phase correction command signal to the timer value calculation unit 42 to adjust the phase of the inverter output voltage in the advancing direction so that the integrated signal ∫VMNdt becomes large.

Therefore, when the configuration of FIG. 3 is adopted, efficiency control by phase and speed control by voltage can be performed. FIG. 12A is a diagram for explaining the operation of switching the duty ratio of PWM to perform the maximum efficiency operation. When the load torque increases, the phase correction angle advances as the load torque increases and the phase ( The phase correction angle changes in the decreasing direction), and the PWM duty ratio is switched according to the phase correction angle at that time. On the contrary, when the load torque occurs, the phase correction angle is delayed as the load torque occurs (the phase correction angle increases).
The duty ratio of the PWM is switched according to the phase correction angle at that time. Further, the phase for judging switching is provided with a differential to prevent hunting.

However, as shown in FIGS. 12B and 12C, the level of the PWM smoothing signal can be set higher than the maximum efficiency level to cope with acceleration / deceleration or heating operation. Here, since an extra torque is required at the time of motor acceleration than at the time of steady operation, it is possible to cope with an extra load torque by degrading the motor efficiency and passing a current. Further, in the heating operation, it is possible to heat the refrigerant by utilizing the heat generation of the winding due to the efficiency of the compressor motor being intentionally deteriorated in the air conditioner, and to speed up the heating. In addition,
In FIGS. 12B and 12C, the duty ratio of PWM is set to be constant regardless of the load torque, but it goes without saying that the duty ratio may be changed depending on the load torque and the operating frequency.

FIG. 13 is a flow chart for explaining the interrupt processing for each position signal. In step SP1, it is determined whether the position signal is the rising edge. If it is determined that the position signal is rising edge, step SP2
At, it is determined whether the level detection signal is at high level. If the level detection signal is at high level, a delay correction request is output in step SP3. vice versa,
If the level detection signal is low level, step SP4
In step 1, the correction request is output.

If it is determined in step SP1 that the position signal does not rise, and if the processing in step SP3 or step SP4 has been performed, step SP
In 5, it is determined whether or not the delay correction request is output. If the delay correction request is output, 1 deg is added to the previous phase correction angle command in step SP6. On the contrary, if the delay correction request is not output,
In step SP7, it is determined whether or not the advance correction request is output. If the advance correction request is output, 1 deg from the previous phase correction angle command in step SP8.
Is subtracted.

When the processing of step SP6 or step SP8 is performed, the duty ratio of PWM according to the phase correction angle is set to output the PWM signal in step SP9, the reset signal is output in step SP10, and the step SP11. In, a conventional process such as speed control is performed, and the process directly returns to the original process.

Therefore, each time the position signal rises, a delay correction request or a lead correction request is output, the phase correction angle command is changed by 1 deg according to the type of correction request, and the PWM duty ratio corresponding to the phase correction angle is changed. Set PW
The M signal can be output, and the brushless DC motor can be operated at a predetermined efficiency by smoothing the PWM signal and determining the magnitude of the integrated signal.

FIG. 14 is a block diagram showing the configuration of the microcomputer 4 in which the efficiency is controlled by the voltage and the speed is controlled by the phase. The block diagram of FIG. 14 differs from the block diagram of FIG. 3 in that the phase determination command signal from the level determination unit 51 is transferred to the timer value calculation unit 42 and the level detection signal switching unit 5
3, a voltage command is output from the level determination unit 51 instead of being supplied to the PWM control unit 3, and the voltage command is supplied to the PWM unit 52.
And a voltage command signal from the speed control unit 45 to the PWM unit 52.
Instead of supplying the phase correction command signal from the speed control unit 45, the phase correction command signal is supplied to the timer value calculation unit 42 and the level detection signal switching unit 53. Note that the other components are the same as the corresponding components in FIG. 3, so description thereof will be omitted.

FIG. 15 is a flow chart for explaining the interrupt processing for each position signal. This flowchart is different from the flowchart of FIG. 12 only in the processing of steps SP6 and SP8, and the processing of the other steps is the same. That is, 1V is added to the previous voltage command in step SP6, and 1V is subtracted from the previous voltage command in step SP8.

Therefore, by adopting the configuration of FIGS. 14 and 15, it is possible to perform efficiency control by voltage and speed control by phase. In the above embodiment, the PWM duty ratio is changed based on the phase correction angle, but it goes without saying that the PWM duty ratio may be changed based on the operating frequency or the load torque. .

It is also possible to directly use the potential difference signal instead of the integration signal.

[0045]

According to the invention of claim 1, the brushless DC is set by setting the target value for judging the level of the potential difference signal or the integrated signal to the level of the signal at the desired efficiency.
There is a unique effect that the motor can be operated at a desired efficiency. The invention of claim 2 has the same effect as that of claim 1.

In addition to the effect of claim 1 or claim 2, the invention of claim 3 has a simpler structure as compared with the case of providing a plurality of level determination means so that a plurality of target values can be selectively adopted in advance. In addition to the above, it has a peculiar effect that cost reduction can be achieved. In addition to the effect of claim 1 or claim 2, the invention of claim 4 simplifies the configuration as compared with the case of providing a plurality of level determination means so that a plurality of target values can be selectively adopted in advance. In addition to the above, there is a peculiar effect that cost reduction can be achieved.

According to the invention of claim 5, when an arbitrary operating condition is set, a target value corresponding to the operating condition is set, and the operation can be performed at a predetermined efficiency determined based on the target value. There is a unique effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a brushless DC motor drive control device of the present invention.

FIG. 2 is an electric circuit diagram showing a configuration of a level detector.

FIG. 3 is a block diagram showing an example of a configuration of a microcomputer.

FIG. 4 is an electric circuit diagram showing in detail the configurations of a rotational position detector and a level detector connected to a microcomputer.

FIG. 5 is a diagram showing signal waveforms of respective parts of the brushless DC motor drive control device.

FIG. 6 is a diagram showing a relationship between a phase correction angle and an integrated signal level.

FIG. 7 is a diagram showing a relationship between a load torque and a duty ratio of PWM.

FIG. 8 is a diagram showing a relationship between a load torque and a phase correction angle.

9 is a diagram showing signal waveforms of respective parts of the electric circuit diagram of FIG.

FIG. 10 is a diagram showing a relationship between a PWM smoothing signal and a PWM duty ratio.

FIG. 11 is an electric circuit diagram showing in detail another configuration of the rotational position detector and the level detector connected to the microcomputer.

FIG. 12 is a diagram showing the relationship between load torque and PWM duty ratio during maximum efficiency operation, acceleration / deceleration operation, and heating operation.

13 is a flowchart illustrating an interrupt process in the microcomputer of FIG.

FIG. 14 is a block diagram showing another example of the configuration of a microcomputer.

15 is a flowchart illustrating an interrupt process in the microcomputer of FIG.

FIG. 16 is a block diagram showing a conventional brushless DC motor drive control device.

FIG. 17 is a diagram showing an operating area of the compressor in the relationship between the operating frequency and the torque of the brushless DC motor.

[Explanation of symbols]

 1 Stator 1a, 1b, 1c Armature coil 2 Resistance circuit 3 Rotation position detector 4 Microcomputer 6 Level detector 10 Rotor 20 Inverter section 53 Level detection signal switching section 62 PWM smoothing section 62 'D / A converter

Claims (5)

[Claims] 1. A rotor (10) having a multi-pole magnet.
And the armature coil (1a) (1
b) Three-phase Y in parallel with the stator (1) having (1c) and the armature coils (1a) (1b) (1c).
The connected resistance circuit (2) and the armature coil (1)
a) A potential difference signal representing a potential difference between the neutral point of (1b) (1c) and the neutral point of the resistance circuit (2) is detected, and based on the potential difference signal, the rotor (10) and the fixed portion are fixed. A rotational position detecting means (3) for detecting a relative rotational position with respect to the child (1) and outputting a position signal whose level is switched according to the rotational position, and the position of the rotational position detecting means (3). Based on a signal, the armature coils (1a) (1b)
The inverter unit (2) that switches the voltage pattern of (1c)
0), a brushless DC motor drive controller, which receives the potential difference signal or an integrated signal obtained by integrating the potential difference signal, and determines whether the level of the signal is equal to or higher than a target value. (6), target value setting means (53) (62) (62 ') for variably setting the target value given to the level judging means (6), and based on the judgment result of the level judging means (6). A brushless DC motor drive control device comprising: a control unit that controls switching of the voltage pattern so that the level of the signal becomes the target value. 2. The control means, based on the determination result of the level determination means (6), changes the time from the position signal until the voltage pattern is switched so that the level of the signal becomes the target value. The brushless DC motor drive control device according to claim 1, wherein the brushless DC motor drive control device adjusts or adjusts a voltage. 3. The target value setting means (53) (62)
Is a pulse width modulation means (53) and a duty ratio setting means (53) for setting the duty ratio of the pulse width modulation means.
And a smoothing means (6) for smoothing the pulse signal output from the pulse width modulating means (53) and outputting it as a target value.
2) The brushless DC motor drive control device according to claim 1 or 2, further comprising: 4. The target value setting means (53) (62 ')
Is a pulse width modulation means (53) and a duty ratio setting means (53) for setting the duty ratio of the pulse width modulation means.
And D / which converts the pulse signal output from the pulse width modulation means (53) into an analog signal and outputs it as a target value.
The brushless DC motor drive control device according to claim 1 or 2, further comprising an A conversion means (62 '). 5. The target value setting means (53) (62)
(62 ') is a brushless DC motor drive control apparatus in any one of Claim 1 to 4 which sets a target value according to the operating condition of a brushless DC motor.