JP3467233B2 - Motor torque control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation control technique for a motor (for example, a DC brushless motor) used in a compressor such as an air conditioner or a refrigerator, and more particularly, it can reduce vibration and noise. The present invention relates to a torque control method for a motor.

[0002]

2. Description of the Related Art A compressor, which has been generally used in an air conditioner or a refrigerator, is an important component of a refrigeration cycle and compresses a refrigerant to perform heat exchange in a high temperature / high pressure state. Usually, this compression operation is roughly divided into three processes. First, there is a suction process for filling the refrigerant in the cylinder inside the compressor, then there is a compression process for compressing the refrigerant in the cylinder, and finally the compressed refrigerant is There is a discharge process that discharges to the outside of the compressor.

[0003] Also, the compressor by its compression mechanism, a rotary type, reciprocating type, there is a scroll type, and among them Rotary scheme than the other method, the number of components less simple structure, low cost, cylinder By rotating inside, each process of suction, compression and discharge is performed. Therefore, there is a problem that vibration and noise increase due to load fluctuation due to suction, compression, and discharge during one rotation and eccentricity of the rotating shaft.

A twin rotary system in which two cylinder parts are provided and the rotary pistons are rotated by 180 degrees to cancel each other's vibrations has been put into practical use, but compared with a single rotary system having one cylinder part, There were factors such as the structure becoming complicated, the cost increasing, and the efficiency decreasing.

Therefore, a method of controlling the motor torque of the single rotary system to suppress vibration and noise has been devised. In this method, the motor torque is increased at a position where the load torque is large, and conversely, at the position where the load torque is small, the motor torque is cut to keep the rotor speed constant during one rotation to reduce vibration. Is. As a method of this kind, the output voltage of the inverter device is changed according to the rotational position of the rotor by using a torque pattern stored in advance in the storage means so as to correspond to the load torque fluctuation due to the suction process and the compression process of the compressor. There is a method of performing torque control during one rotation.

Here, if this torque pattern is fixed at all times regardless of the number of rotations of the motor, a sufficient vibration control capability cannot be exerted in a wide range of rotations, and a plurality of torque patterns are previously set. Has been devised, and a method of selecting according to the number of revolutions has been devised.

As described above, as a conventional example of a motor control method for controlling torque using a plurality of torque patterns in a compressor having a single rotary structure in which the load fluctuation during one rotation is large, Japanese Patent Laid-Open No. 6-311778, etc. There is.

[0008]

However, in the above torque control method for a motor, when the rotational speed is lowered from the state where the compressor is operating at a high rotational speed, the motor torque follows the lowering of the rotational speed. Although it drops well, the followability of the load (refrigerant pressure) is poor, and the drop in the load is slower than the drop in the motor torque due to the drop in the motor rotation speed. For this reason, if the range of the torque compensation amount when reducing the rotation speed from a high load is too wide, the current value in the state where the torque compensation is performed on the positive side becomes large, and there is a risk that the overcurrent level will be reached and the compressor will stop. is there. Therefore, in the conventional motor torque control method, configured with a small set the working rotational speed of the descent rate so as not to over-current, to be smaller by a margin to some extent the torque compensation amount when decelerating from high speed to low speed Was.

The present invention has been made in view of the above problems, and it is possible to prevent the compressor from stopping without lowering the rate of increase / decrease in the operating speed, and further to reduce vibration in the steady state more than ever before. Another object of the present invention is to provide a motor torque control method capable of controlling the motor torque.

[0010]

To solve the above problems, a motor for driving a load, an inverter for driving the motor, a rotor position detecting means for detecting a rotor position of the motor, and the rotor are provided. The average rotation speed of one rotation of the motor is detected based on the information of the position detecting means, the target rotation speed is compared with the average rotation speed, and the average rotation speed control PWM duty is adjusted according to the comparison result to adjust the average rotation speed of the motor. An average speed control means for controlling the number,
A torque pattern corresponding to the average rotation speed is selected and read from a plurality of torque patterns stored in advance in the storage means, and the read torque pattern is used to compensate for the average rotation speed PWM duty and finally. A motor torque control method for controlling a motor torque, comprising: a motor rotation speed fluctuation control means for suppressing an instantaneous rotation speed fluctuation during one rotation of the motor by setting an output PWM duty output to an inverter. When the target rotation speed of the motor is changed from low speed to high speed, the width of the torque compensation amount of the torque pattern is once narrower than a predetermined value, and the torque compensation amount is set to a predetermined value after a predetermined time has elapsed after reaching the target rotation speed. Return to value.

Further, a motor for driving a load, an inverter for driving the motor, a rotor position detecting means for detecting a rotor position of the motor, and one rotation of the motor based on information of the rotor position detecting means. Average rotation speed control means for detecting the average rotation speed and comparing the target rotation speed with the average rotation speed, adjusting the average rotation speed control PWM duty according to the comparison result, and controlling the average rotation speed of the motor, A torque pattern corresponding to the average rotation speed is selected from a plurality of torque patterns stored in the storage means and read out, and the average rotation speed PWM duty is compensated finally using the read torque pattern. A motor that suppresses an instantaneous rotation speed fluctuation during one rotation of the motor by setting an output PWM duty output to an inverter A method of controlling a torque of a motor, comprising: controlling a motor speed by controlling a rotational speed variation, wherein when a target rotational speed of the motor is changed from a high speed to a low speed, a width of a torque compensation amount of the torque pattern is set to a predetermined value. The torque compensation amount is returned to a predetermined value after a predetermined time has elapsed after reaching the target rotation speed.

In the motor torque control method, the ratio of narrowing the width of the torque compensation amount to a value smaller than a predetermined value is changed according to the operating speed increase rate when the target speed is changed.

Further, in the motor torque control method, the ratio of making the width of the torque compensation amount narrower than a predetermined value is changed according to the operating rotation speed lowering rate when the target rotation speed is changed.

In the motor torque control method, the difference between the current rotation speed and the target rotation speed when the target rotation speed is changed
The ratio of making the width of the torque compensation amount narrower than a predetermined value is changed.

Further, in the motor torque control method, a DC current detecting means for detecting a DC current flowing through the inverter unit is provided, the DC current is detected while the rotational speed is changing, and the detected DC current is used to detect a torque compensation amount. The ratio of narrowing the width of is smaller than a predetermined value is changed.

Further, in the motor torque control method, a load torque detecting means for detecting a load torque is provided at a connecting portion between the motor and the load, the load torque is detected while the rotational speed is changing, and the detected load torque is detected. , The ratio of narrowing the width of the torque compensation amount below a predetermined value is changed.

Further, in the motor torque control method, a vibration sensor is attached to the load, a vibration value is detected while the rotational speed is changing, and the torque compensation amount is maintained so that the detected vibration value is maintained within a predetermined range. The ratio of narrowing the width of is smaller than a predetermined value is changed.

Further, in the torque control method for a motor, the width of the torque compensation amount that is once narrowed during the change of the motor rotation speed is gradually returned to the predetermined value after a predetermined time has elapsed after reaching the target rotation speed.

In the motor torque control method, the load torque is increased or decreased from the value at the time of reference load of the PWM duty for adjusting the voltage or current applied to the motor at the current rotational speed of the motor measured in advance. Estimate the load condition from the quantity.

In the motor torque control method, voltage detecting means for detecting a DC voltage applied to the inverter section and current detecting means for detecting a DC current supplied from the DC voltage are provided, and Power consumption is detected from the current, and the load torque is estimated based on the power consumption and the rotation speed of the motor.

Further, in the motor torque control method, an input current detecting means for detecting an AC current input to the rectifier circuit in the preceding stage of the inverter unit is provided, and the load torque is the load torque and the AC current is the motor current. Estimate based on the rotation speed of.

Further, in the motor torque control method, there are provided voltage detecting means for detecting an AC voltage applied to the rectifier circuit in the preceding stage of the inverter section, and current detecting means for detecting an AC current supplied from the AC voltage. Power consumption is detected from the voltage and the current, and the load torque is estimated based on the power consumption and the rotation speed of the motor.

In the motor torque control method, motor current detecting means for detecting a motor current flowing through the winding of the brushless motor is provided, and the motor current detecting means has one or more current sensors. The load torque is estimated based on the motor current and the rotation speed of the motor.

The motor is a brushless motor used in a compressor of an air conditioner.

The motor is a brushless motor used in a refrigerator compressor.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing an embodiment of a speed control device for a compressor motor according to the present invention. In FIG. 1, 1 is an AC power supply from a commercial power supply, 2 is a rectifier circuit that converts AC into DC, and 3 is a smoothing circuit that smoothes ripples of DC voltage. Although a full-wave rectifier circuit is shown in this figure, a voltage doubler rectifier circuit may be used. Reference numeral 4 denotes an inverter circuit, in which six semiconductor switching elements 4a to 4f are connected in a three-phase bridge shape and are connected to the three-phase brushless motor 5. In addition, a regenerative current is passed through the inverter circuit 4 and diodes 4g to 4l are connected in parallel to each semiconductor switch element for element protection. Reference numeral 6 is a power factor correction circuit such as a reactor for improving the power factor reduction in the smoothing circuit section.

The rotor position detecting portion of the present invention detects the induced voltage according to the rotor magnetic pole position by the induced voltage detecting circuits 7a to 7c connected to the three-phase windings of the brushless motor 5, and detects the three phases of the brushless motor. The output voltage of the reference voltage detection circuit of 8 which forms a virtual neutral point by connecting each winding is compared by the comparison detection circuits of 9a to 9c, and a pulse signal corresponding to the rotor position is output. 1 if rotor has 4 poles
Twelve pulses are generated per revolution.

Reference numeral 10 denotes a control unit, which generates drive signals for commutating the semiconductor switching elements 4a to 4f of the four inverter circuits based on the detected rotor position signal,
11 to the drive circuit. Further, the average rotation speed of one rotation of the motor detected based on the rotor position signal is compared with the target rotation speed, and the average rotation speed control PWM is performed according to the comparison result.
Average rotation speed control for adjusting the duty and controlling the average rotation speed of the motor, and selecting and reading a torque pattern corresponding to the average rotation speed from a plurality of torque patterns stored in advance in the storage means, and reading this By using the torque pattern to compensate the average rotation speed PWM duty and making it the output PWM duty that is finally output to the inverter, the rotation speed fluctuation control of the motor that suppresses the instantaneous rotation speed fluctuation during one rotation of the motor is performed. Drive circuit 11
Then, the voltage or current applied to the brushless motor 5 is changed by changing the duty, and the rotation speed and the torque are controlled.

FIG. 2 shows voltage waveforms at various parts of the speed control device for the compressor motor shown in FIG. FIG. 2A shows the relationship between the induced voltage waveform from each winding of the brushless motor and the reference voltage. If the rotor magnetic pole of the brushless motor has four poles, one rotation makes four magnetic pole changes.
The induced voltage waveform is generated for two cycles. Further, the brushless motor is a three-phase star connection, the induced voltage waveform generated in each winding, in a state where displacement is 120 ° Dzu single phase. The result of comparing the induced voltage and the reference voltage is (b).
2 is a rotor position signal waveform of. When the induced voltage is higher than the reference voltage, the comparison result is High.
When the output is made to be ow, a pulse having a rising edge or a falling edge is obtained at the zero cross point where the magnetic pole changes. This edge pulse is generated 12 times per rotation, and the absolute position of the rotor can be detected in 12 sections. However,
The induced voltage waveform of (a) and the rotor position signal waveform of (b) are shown to have the same phase in the same winding, but in reality, the induced voltage and rotor position signal are There is a phase delay.

The control unit 10 creates a signal for driving the brushless motor based on the rotor position signal. The drive signal (c) turns on the switching element (4a in FIG. 1) of the U-phase upper arm when the rising edge of the rotor position signal Hu is detected, for example. Next, when the rising edge of Hv is detected, the switching element of the U-phase upper arm is turned off and the switching element of the V-phase upper arm is turned on. When the falling signal of Hw is detected, the switching element of the V-phase lower arm is commutated from the switching element of the V-phase lower arm. In this way, each time the edge of the rotor position signal is detected, the switching elements of the inverter circuit are commutated to drive the brushless motor.

In order to control the rotation speed and torque, PWM chopping is superimposed on the normal drive signal to control the motor applied voltage and current. In the figure, only the upper arm has PW
Although M chopping is performed, the lower arm or the upper and lower arms may be used.

FIG. 3 shows a case where a single-rotor compressor having a large load fluctuation during one rotation is controlled using a plurality of torque patterns. The data (torque pattern) as shown in FIG. 4, which is the amount of torque compensation for each mechanical position of the rotor, is stored in ROM in advance. When the motor torque is controlled by the PWM duty, the data to be stored in the ROM is a compensation amount of the PWM duty, and the PWM duty is compensated so that the current becomes large in a section where the load torque is large, and the load torque is small. The PWM duty is compensated so that the current is reduced in the section, but it is determined by making experiments and simulations so that the vibration and noise of the compressor are low and the efficiency of the brushless motor is high. Also, the compensation amount must be changed according to the load. Therefore, the control performance can be improved by dividing the rotational speed into a plurality of regions and reading out the torque pattern corresponding to the rotational speed from the storage means and using it.

Then, a predetermined PWM duty compensation amount is read from this storage unit in accordance with the state corresponding to the rotor mechanical position to control the PWM duty for each rotor mechanical position.

Here, the state means that one rotation of the rotor is divided for each energization mode, that is, for each commutation as shown in FIG. 5, and is divided into 12 in the 4-pole brushless motor, and 12 states from state 0 to state 11. have. However,
The energization modes of the state n and the state n + 6 (n: an integer of 0 to 5) are the same.

In the method of controlling a motor using a plurality of torque patterns as described above, when the rotational speed is increased from the state where the compressor is operating at a low rotational speed, a torque for accelerating the motor is required and the current also increases. . For this reason, if the width of the torque compensation amount is too wide, the current value in the state where the torque compensation is performed on the positive side becomes very large, and there is a risk that the overcurrent level is reached and the compressor stops.

Therefore, in order to prevent the current value from reaching the overcurrent level during motor acceleration, for example, the width of the torque compensation amount is set to 1/2 of the predetermined value and the PWM duty is determined.

Here, the target rotation speed is changed from 1000 rpm to 2000 rpm, the motor starts accelerating, and the time when the average rotation speed reaches 1500 rpm is shown. However, the average rotation speed control PWM duty is set to 15%.

(1-1) The average rotation speed control PWM duty calculated by the average rotation speed control routine is read out independently of the torque control processing routine. (= 15%) (1-2) The PWM duty compensation amount in the current state of the torque pattern selected according to the rotation speed is read from the data table of FIG. (Torque pattern 2) (1-3) The PWM duty finally output for each state is calculated by the following equation.

Output PWM Duty = Average Rotation Control PWM Duty × (1 + PWM Duty Compensation Amount × (1/2) (For State 2: 15% × (1 + 0.3 × 1/2) =
17.25%) Here, the torque pattern when the width of the torque compensation amount is changed as described above and when the change is not made, and D
The C current waveform is shown in FIG.

If no change is made, the current value in the state where torque compensation is performed on the positive side becomes very large. However, if the width of the torque compensation amount of the present invention is changed, torque compensation is performed on the positive side. The current value in the state can be kept small.

Further, here, when the target number of revolutions of the motor is changed from low speed to high speed, the width of the torque compensation amount is uniformly set to 1/2 of the predetermined value.
It may be changed to 4, 1/3, or the like. Alternatively, when accelerating the motor, the ratio of narrowing the width of the torque compensation amount below the predetermined value is
It is desirable to make adjustments by experiments and simulations in consideration of the margin to the overcurrent level, fluctuations in the rotational speed of the compressor, vibration, and noise. Second Embodiment In the first embodiment, the case where the target rotation speed of the motor is changed from the low speed to the high speed has been described.
It shows about changing from high speed to low speed. If the rotation speed is reduced while the compressor is operating at a high rotation speed, the motor torque follows the decrease in the rotation speed with good followability, but the followability of the load (refrigerant pressure) is poor, and the motor rotation speed is low. The load is slowed down more slowly than the motor torque is lowered. For this reason, if the range of the torque compensation amount when the rotation speed is reduced from a high rotation speed in a high load state is too wide, the current value in the positive torque compensation state becomes large, and the overcurrent level is reached and the compressor is reached. May stop.

Therefore, in order to prevent the current value from reaching the overcurrent level during deceleration of the motor, for example, the width of the torque compensation amount is set to 1/2 of the predetermined value and the PWM duty is determined.

In this example, the target rotation speed is changed from 2000 rpm to 1000 rpm, the motor starts decelerating, and the average rotation speed reaches 1500 rpm. However, the average rotation speed control PWM duty is set to 15%.

(2-1) The average rotation speed control PWM duty calculated by the average rotation speed control routine is read out independently of the torque control processing routine.

(= 15%) (2-2) The PWM duty compensation amount in the current state of the torque pattern selected according to the rotation speed is read from the data table of FIG.

(Torque pattern 2) (2-3) The PWM duty finally output for each state is calculated by the following equation.

Output PWM Duty = Average Rotation Control PWM Duty × (1 + PWM Duty Compensation Amount × (1/2) (If State 2: 15% × (1 + 0.3 × 1/2) =
17.25%) Here, the torque pattern when the width of the torque compensation amount is changed as described above and when the change is not made, and D
The C current waveform is the same as that described with reference to FIG. If the change is not made, the current value in the positive torque compensation state becomes very large. However, if the range of the torque compensation amount of the present invention is changed, the current value in the positive torque compensation state is changed. The current value can be kept small.

Further, here, when the target rotation speed of the motor is changed from the high speed to the low speed, the width of the torque compensation amount is uniformly set to 1/2 of the predetermined value.
It may be changed to 4, 1/3, or the like. Alternatively, during deceleration of the motor, a torque pattern different from that at the time of stable rotation speed in which the width of the torque compensation amount is set narrower than a predetermined value may be selected.

The rate of narrowing the width of the torque compensation amount during deceleration of the motor from the predetermined value is the same as that of the first embodiment in consideration of the margin up to the overcurrent level, the rotational speed fluctuation of the compressor, vibration, and noise. It is desirable to make adjustments and make a decision by simulation. (Third Embodiment) In the first embodiment, when the target rotation speed of the motor is changed from low speed to high speed, the ratio of narrowing the width of the torque compensation amount below the predetermined value is uniformly set to 1/2. The rate at which the width of the torque compensation amount is narrower than a predetermined value may be changed according to the operating speed increase rate at the time of change.

For example, the operating speed increase rate is large and is 1
When performing rapid acceleration such as 500 rpm per second, the width of the torque compensation amount is set to 1/2 of the predetermined value, and when the operating speed increase rate is small and gradual acceleration such as 500 rpm per second is performed, torque compensation is performed. The width of the quantity is set to 4/5 of the predetermined value or the like.

Here, a case where the operating speed increase rate is large and the width of the compensation amount is 1/2 of the predetermined value, and a case where the operating speed increase rate is small and the range of the compensation amount is 4/5 of the predetermined value, The torque pattern and DC current waveform are shown in FIG.

Looking at the torque pattern, the range of compensation amount becomes wider when the rate of increase is smaller, but the energy required for acceleration is small because the acceleration is gentle, so the current is small and the DC current waveform shows. As described above, the current peak value in the state in which the torque compensation is performed on the positive side has a large operating speed increase rate, and is not much different from the case where the width of the compensation amount is ½ of the predetermined value. Fourth Embodiment In the second embodiment, when the target rotation speed of the motor is changed from the high speed to the low speed, the ratio of narrowing the width of the torque compensation amount to be smaller than the predetermined value is uniformly set to 1/2. The ratio of narrowing the width of the torque compensation amount to a value smaller than a predetermined value may be changed according to the operating speed reduction rate when the number is changed.

For example, the operating speed reduction rate is large and is 1
When performing rapid deceleration such as deceleration of 500 rpm per second, the width of the torque compensation amount is set to 4/5 of a predetermined value or the like.

As for the torque pattern, when the lowering rate is smaller, the range of compensation amount is wider, but since the deceleration is slower, the decrease in load (pressure) almost follows the decrease in rotational speed, so the current value is also. The current peak value in the state in which the torque is reduced to the positive side is almost the same as that in the case where the operating rotation speed decrease rate is large and the width of the compensation amount is 1/2 of the predetermined value. (Fifth Embodiment) In the first or second embodiment, when the target rotation speed of the motor is changed from low speed to high speed or from low speed to high speed, the ratio of narrowing the width of the torque compensation amount below a predetermined value is set. However, the ratio of narrowing the width of the torque compensation amount to a value smaller than a predetermined value may be changed depending on the difference between the current rotational speeds when the target rotational speed is changed.

For example, when the target rotation speed is changed, the difference between the current rotation speed and the target rotation speed is large and 5000 rpm to 1000 r.
When abrupt deceleration or acceleration such as a change to pm is performed, the width of the torque compensation amount is set to 1/2 of the predetermined value, and the difference in the number of revolutions is small, and the deceleration or acceleration is gentle such as a change from 1500 rpm to 1400 rpm. When performing, the width of the torque compensation amount is set to 4/5 of the predetermined value or the like.

As for the torque pattern, when the difference between the current rotation speed and the target rotation speed at the time of changing the target rotation speed is small, the range of compensation becomes wider, but it is necessary for acceleration because the acceleration is gentle during acceleration. Energy and current are small,
During deceleration, deceleration is gentle, so the energy required for acceleration is small and the current required is small. During deceleration, the deceleration is gentle, so the drop in load (pressure) almost follows the decrease in rotational speed.
The current value also decreases, and the current peak value in the state where torque compensation is performed on the positive side has a large difference between the current rotation speed and the target rotation speed when the target rotation speed is changed, and the compensation amount width is set to 1/2 of the predetermined value. There is not much difference from the case. (Embodiment 6) In Embodiment 1 or Embodiment 2, when the target rotation speed of the motor is changed from a low speed to a high speed or when it is changed from a low speed to a high speed, the width of the torque compensation amount is uniformly 1 / th of a predetermined value. Although set to 2, DC that detects the DC current flowing through the inverter
A current detecting means may be provided to detect a DC current while the rotational speed is changing, and the ratio of making the width of the torque compensation amount narrower than a predetermined value may be changed by the detected DC current.

For example, when the DC current is large and the margin to the overcurrent level is small, the width of the torque compensation amount is set to 1/2 of the predetermined value, and when the DC current is small and the margin to the overcurrent level is large. Sets the width of the torque compensation amount to 4/5 of a predetermined value or the like.

As for the torque pattern, when the difference between the current rotational speed and the target rotational speed at the time of changing the target rotational speed is small, the range of the compensation amount is wide, but the acceleration is gentle at the time of acceleration and therefore necessary for acceleration. The energy is small and the current is small, and the deceleration is gentle during deceleration, so the decrease in load (pressure) almost follows the decrease in rotation speed, so the current value also becomes small, and torque compensation is performed in the positive side. The current peak value has a large difference between the current rotation speed and the target rotation speed when the target rotation speed is changed, and is not much different from the case where the width of the compensation amount is ½ of the predetermined value. (Embodiment 7) In Embodiment 1 or Embodiment 2, when the target rotation speed of the motor is changed from a low speed to a high speed or from a low speed to a high speed, the width of the torque compensation amount is uniformly ½ of a predetermined value. However, the load state may be detected while the rotational speed is changing, and the ratio of making the width of the torque compensation amount narrower than a predetermined value may be changed depending on the detected load state.

For example, when the load is heavy and a large current is required, the width of the torque compensation amount is set to 4/5 of the predetermined value.
And so on.

As for the torque pattern, when the load is light, the range of compensation amount is wider, but since the load is light, the current is small, and the current peak value in the positive torque compensation state is the load. Heavily compensate for the range of 1/2 the specified value
There is not much difference from the case. (Embodiment 8) In Embodiment 1 or Embodiment 2, when the target rotation speed of the motor is changed from a low speed to a high speed or from a low speed to a high speed, the width of the torque compensation amount is uniformly 1 / th of the predetermined value. Although the vibration sensor is attached to the load, the vibration value is detected while the rotation speed is changing, and the width of the torque compensation amount is narrower than the predetermined value so that the detected vibration value is maintained within the predetermined range. You may change the ratio to do.

For example, when the vibration value is small and there is a sufficient margin from the predetermined range, the width of the torque compensation amount is made significantly smaller than the predetermined value, and the current value in the state where the torque compensation is performed on the positive side is set to the torque compensation amount. By keeping the width small compared to the case where the width is large, the margin for the overcurrent level is increased. (Ninth Embodiment) In the first or second embodiment, the width of the torque compensation amount is set to a predetermined value after a predetermined time has elapsed after the target rotation speed has reached the target torque rotation speed during which the width of the torque compensation amount is narrowed. However, if the torque compensation amount range is not suddenly returned to the specified value but gradually returned to the specified value over time, fluctuations in the rotational speed will be smaller, which will result in lower noise and vibration of the motor. Can be achieved.

For example, the width of the torque compensation amount which is ½ of the predetermined value while the rotation speed is changing is set to 3/4 of the predetermined value after the predetermined time T1 has elapsed after reaching the target rotation speed, and further the predetermined time T2 has elapsed. After that, the value is set to 4/5 of the predetermined value, and after the predetermined time T3 has elapsed, the value is returned to the predetermined value. (Example 10) The load torque detected in Example 7 is the number of rotations of the motor and A.
Current value such as C current or motor winding current,
It is also possible to estimate from the amount of increase in the power consumption or the PWM duty for adjusting the voltage or current applied to the motor at the current rotation speed from the value at the reference load. Therefore, by using these as the load torque detecting means in the eighth embodiment, the width of the torque compensation amount is adjusted according to the load torque, and the margin for the overcurrent level is secured.

Further, in the first or second embodiment, since it can be realized by the software of the microcomputer which is the control unit 10, there is no problem of cost increase. In addition, when the motor is used as a brushless motor in an air conditioner or a compressor of a refrigerator, vibration of the compressor can be reduced, so that there is no need to leave room in the piping of the outdoor unit, that is, a compact outdoor unit or refrigerator. Can be realized.

The first to first embodiments of the present invention are described.
Although 0 has been described, a plurality of the above embodiments may be combined and implemented.

[0066]

According to the present invention, when the target rotation speed of the motor is changed from low speed to high speed, the width of the torque compensation amount of the torque pattern is once narrower than a predetermined value, and after the rotation speed is stabilized, the torque compensation amount is reduced. Since the value is returned to the predetermined value, there is a large margin to the overcurrent level when the motor speed changes, and it is possible to avoid the stop due to the overcurrent without reducing the motor speed increase rate. Further, since the torque compensation amount when the rotation speed is stable can be set to be somewhat larger than the conventional value, the vibration after the stable rotation can be made smaller than the conventional value.

Further, when the target rotation speed of the motor is changed from a high speed to a low speed, the width of the torque compensation amount of the torque pattern is once narrower than a predetermined value, and after the load condition stabilizes, the torque compensation amount is returned to the predetermined value. In addition, when the motor speed changes, a large margin for the overcurrent level can be obtained, and the stop due to the overcurrent can be avoided without reducing the motor speed decrease rate. Further, since the torque compensation amount when the load is stable can be set to be somewhat larger than that in the conventional case, the vibration after the stable rotation can be made smaller than in the conventional case.

Further, by changing the ratio of narrowing the width of the torque compensation amount to a value smaller than a predetermined value in accordance with the operating rotation speed increase rate when the target rotation speed is changed, the overcurrent level when the motor rotation speed changes. It is possible to reduce the vibration of the motor while the motor speed is changing, while maintaining the margin to the above.

Further, by changing the ratio of narrowing the width of the torque compensation amount to a value smaller than a predetermined value in accordance with the operating rotation speed lowering rate when changing the target rotation speed, the overcurrent level when the motor rotation speed changes. It is possible to reduce the vibration of the motor while the motor speed is changing, while maintaining the margin to

Further, by changing the ratio of making the width of the torque compensation amount narrower than a predetermined value according to the difference between the current rotational speed and the target rotational speed when the target rotational speed is changed, the overcurrent level is changed when the motor rotational speed changes. It is possible to reduce the vibration of the motor while the motor speed is changing, while maintaining the margin.

Further, the DC current is detected while the rotational speed is changing, and the ratio of making the width of the torque compensation amount narrower than a predetermined value is changed by the detected DC current, so that the margin of the overcurrent level is changed when the motor rotational speed changes. It is possible to reduce the vibration of the motor while the motor speed is changing, while maintaining the degree of accuracy.

Further, the load torque is detected while the rotational speed is changing,
Depending on the detected load torque, the ratio of narrowing the width of the torque compensation amount to a value smaller than the predetermined value is changed to keep the margin of the overcurrent level when the motor speed changes and to keep the motor low during the motor speed change. Vibration can be achieved.

Further, the vibration value of the load is detected while the rotational speed is changing, and the detected vibration value is maintained within a predetermined range.
By changing the ratio in which the width of the torque compensation amount is narrower than the predetermined value, it is possible to avoid the risk of large vibration such as breakage of the pipe.

Further, the width of the torque compensation amount once narrowed during the change of the motor speed is gradually returned to the predetermined value after a predetermined time has elapsed after reaching the target speed, thereby reducing the noise and vibration of the motor. Can be planned.

Further, by estimating the load torque from the amount of increase in the PWM duty for adjusting the voltage or current applied to the motor at the current rotational speed of the motor measured in advance from the value at the time of the reference load, a special load can be obtained. A torque detector can be dispensed with, and the cost can be reduced.

Further, by estimating the load torque from the amount of increase in the PWM duty for adjusting the voltage or current applied to the motor at the current number of revolutions of the motor measured in advance from the value at the time of the reference load, a special load can be obtained. A torque detector etc. can be dispensed with, and the cost can be reduced.

In addition, the DC current flowing through the inverter, DC
By detecting the voltage to detect the power consumption and estimating the load torque based on the power consumption, a special load torque detector or the like can be dispensed with, and the cost can be reduced.

Further, by detecting the AC current input to the rectifier circuit in the preceding stage of the inverter unit and estimating the load torque based on the AC current, a special load torque detector or the like can be dispensed with, and the cost can be reduced. Can be planned.

Further, the power consumption is detected by detecting the AC current and the AC voltage input to the rectifier circuit in the front stage of the inverter unit, and the load torque is estimated based on the power consumption. And the like can be eliminated, and the cost can be reduced.

Further, by detecting the motor current flowing in the winding of the brushless motor and estimating the load torque based on the motor current, a special load torque detector or the like can be dispensed with, and the cost can be reduced.

Further, since a microcomputer is used for controlling the motor and it is realized by the software of this microcomputer, there is no problem of cost increase, and further, the motor is used as a brushless motor for an air conditioner or a refrigerator. Since it is possible to reduce the vibration of the compressor, it is not necessary to have a margin in the piping of the outdoor unit, that is, the outdoor unit and the refrigerator can be made compact.

[Brief description of drawings]

FIG. 1 is a block diagram of a speed control device for a compressor motor according to an embodiment of the present invention.

FIG. 2 is a voltage waveform of each part of the speed control device for the compressor motor shown in FIG.

FIG. 3 is a diagram showing a torque pattern according to one embodiment of the present invention.

FIG. 4 is torque pattern data according to one embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between states and mechanical angles / electrical angles, and respective energization modes.

FIG. 6 is a diagram comparing the presence / absence of a compensation width change according to an embodiment of the present invention.

FIG. 7 is a diagram illustrating a compensation width change according to the first embodiment of the present invention.

[Explanation of symbols]

1 AC power supply from commercial power supply 2 Rectifier circuit that converts alternating current into direct current 3 Smoothing circuit to smooth the ripple of DC voltage 4 Inverter circuit 5 3-phase brushless motor 6 Power factor correction circuit 7 Induced voltage detection circuit 8 Reference voltage detection circuit 9 Comparison detection circuit 10 Control unit 11 Drive circuit

Claims (15)

(57) [Claims] 1. A motor for driving a load, an inverter for driving the motor, rotor position detecting means for detecting a rotor position of the motor, and one rotation of the motor based on information of the rotor position detecting means. Detecting the average speed and comparing the target speed with the average speed,
The average rotation speed control means for adjusting the average rotation speed control PWM duty according to the comparison result to control the average rotation speed of the motor, and the plurality of torque patterns stored in the storage means in advance are used to correspond to the average rotation speed. Instantaneous rotation during one rotation of the motor by selecting and reading a torque pattern and using the read torque pattern to compensate for the average rotation speed PWM duty and finally set the output PWM duty to be output to the inverter. A motor torque control method for controlling a motor torque, comprising: a motor rotation speed fluctuation control means for suppressing a motor speed fluctuation, wherein when the target rotation speed of the motor is changed from a low speed to a high speed, the torque of the torque pattern is The width of the compensation amount is once narrower than the predetermined value, and the torque compensation amount is set after the predetermined time has elapsed after reaching the target speed. Torque control method of a motor and returning a value. 2. A motor for driving a load, an inverter for driving the motor, a rotor position detecting means for detecting a rotor position of the motor, and one rotation of the motor based on information of the rotor position detecting means. Detecting the average speed and comparing the target speed with the average speed,
The average rotation speed control means for adjusting the average rotation speed control PWM duty according to the comparison result to control the average rotation speed of the motor, and the plurality of torque patterns stored in the storage means in advance are used to correspond to the average rotation speed. Instantaneous rotation during one rotation of the motor by selecting and reading a torque pattern and using the read torque pattern to compensate for the average rotation speed PWM duty and finally set the output PWM duty to be output to the inverter. A motor torque control method for controlling a motor torque, comprising: a motor rotational speed fluctuation control means for suppressing a rotational speed fluctuation, wherein the torque of the torque pattern when the target rotational speed of the motor is changed from a high speed to a low speed. The width of the compensation amount is once narrower than the predetermined value, and the torque compensation amount is set after the predetermined time has elapsed after reaching the target speed. Torque control method of a motor and returning a value. 3. The method according to claim 1 or 2, wherein the ratio of narrowing the width of the torque compensation amount to a value smaller than a predetermined value is changed according to the operating speed increase rate when the target speed is changed.
A method for controlling torque of a described motor. 4. The ratio of narrowing the width of the torque compensation amount to a value smaller than a predetermined value is changed according to the operating rotation speed lowering rate when the target rotation speed is changed.
5. The torque control method for a motor according to any one of 1 . 5. The ratio of narrowing the width of the torque compensation amount to a value smaller than a predetermined value is changed according to the difference between the current rotational speed and the target rotational speed when the target rotational speed is changed . motor torque control method according to any one. 6. A DC current detecting means for detecting a DC current flowing through the inverter section is provided, the DC current is detected during a change in the number of revolutions, and the detected DC current narrows the width of the torque compensation amount below a predetermined value. motor torque control method according to any one of claims 1 to 5, characterized in that varying the rate of. 7. A load torque detecting means for detecting a load torque is provided at a connecting portion between the motor and the load, the load torque is detected during a change in the number of revolutions, and the width of the torque compensation amount is determined by the detected load torque. 7. The ratio according to claim 1, wherein a ratio of narrowing the predetermined value is changed .
The method of controlling torque of a motor according to item 1 . 8. A vibration sensor is attached to the load, a vibration value is detected during a change in the number of revolutions, and a width of the torque compensation amount is set to a predetermined value so that the detected vibration value is maintained within a predetermined range. motor torque control method according to any one of claims 1 to 7, characterized in changing the ratio to narrow. 9. The torque compensation amount width once narrowed during the change of the motor rotation speed reaches a target rotation speed, and after a predetermined time elapses,
A torque control method for a motor, characterized by gently returning to a predetermined value. 10. A load state is estimated from an increase / decrease amount from a value at a reference load of a PWM duty that adjusts a voltage or current applied to the motor at a current rotation speed of the motor in which the load torque is measured in advance. The torque control method for a motor according to any one of claims 1 to 9 , wherein: 11. A voltage detecting means for detecting a DC voltage applied to the inverter section and a current detecting means for detecting a DC current supplied from the DC voltage are provided to detect power consumption from the voltage and the current. The motor torque control method according to any one of claims 1 to 10, wherein the load torque is estimated based on the power consumption and the rotation speed of the motor. 12. An input current detection means for detecting an AC current input to a rectifier circuit in a preceding stage of the inverter section is provided, and the load torque is estimated based on the AC current and a rotation speed of the motor. motor torque control method according to any one of claims 1 to 11. 13. A voltage detecting means for detecting an AC voltage applied to a rectifying circuit in the preceding stage of the inverter section,
Current detecting means for detecting an AC current supplied from the C voltage is provided, power consumption is detected from the voltage and the current, and the load torque is estimated based on the power consumption and the rotation speed of the motor. Claims 1 to 12
5. The torque control method for a motor according to any one of 1 . 14. A motor current detecting means for detecting a motor current flowing through a winding of the brushless motor is provided, and the motor current detecting means has one or more current sensors, and the load torque is the motor current. The torque control method for a motor according to any one of claims 1 to 13 , wherein the estimation is performed based on a rotation speed of the motor. 15. The motor motor torque control method according to any one of claims 1 to 14, characterized in that a brushless motor used in an air conditioner or a refrigerator compressor.