JP2003111483A - Apparatus and method of controlling motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive a motor smoothly at the start control the driving thereof without a position sensor. SOLUTION: A driving system selection section 6 selects intermittent on/off driving at start. When induced voltage generated in a motor coil is detected by starting the motor by means of forced on/off operation, the operation of the motor is shifted to sensor-less operation. When the motor 1 reaches its prescribed rotational speed, the driving system selection section 6 shifts the intermittent energization driving to 180-degree pulse duration driving.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device and a control method thereof for driving and controlling a synchronous motor such as a brushless motor constituted by a rotor having a permanent magnet mounted thereon without a position sensor.

[0002]

2. Description of the Related Art Brushless motors (hereinafter referred to as "motors") used in refrigeration cycle compressors such as air conditioners and refrigerators are capable of operating in a wide range of rotation speeds and highly efficient operation. Is required to be. Therefore, in recent years, a motor driven by an inverter circuit has been used. When driving this motor, it is necessary to energize the stator windings of each phase in synchronization (synchronization) with the rotating rotor position. However, in a compressor used in an air conditioner, a refrigerator, etc., the internal temperature becomes high, and it is difficult to provide a position sensor such as a Hall IC for detecting the rotor position. Drive control of the motor without
Sensorless operation is performed.

In sensorless operation, a certain period of de-energization is provided when energizing the motor coil.
In the meantime, the induced voltage generated in the motor coil by the rotation of the motor is detected from the motor coil terminal, and the energization timing to the motor is determined from the induced voltage. Such intermittent energization drive is generally performed, and among them, the so-called 120-degree energization drive system in which the energization angle is 120 degrees is the most common.

As another driving method, a so-called 18 sinusoidal wave energization, which is driven without providing an energization suspension period, is used.
There is a 0-degree energization drive system. In the 180 degree energization drive method,
Determine the drive timing based on the phase difference between the motor drive voltage and motor current to drive the rotor, or perform predetermined high-speed calculations using the stator winding applied voltage, motor current, and motor device constants to determine the rotor position. Then, the motor is energized by 180 degrees by a method such as calculating and driving the energization timing.

Further, as a conventional example of a configuration for switching between these two driving methods, it is possible to select 180-degree energization drive or intermittent energization drive according to the motor efficiency of the motor.
No. 01-45789.

[0006]

In a motor having a permanent magnet rotor structure, the so-called energization timing is optimized by energizing the motor at an accurate timing corresponding to the rotor position, which is an absolute condition for driving the motor. is there. In order to further improve efficiency and stabilize rotation, it is necessary to set the energization timing to an optimum value determined for each rotation condition.

In the intermittent energization drive including the 120-degree energization drive, the induced voltage relating to the permanent magnet magnetic flux and the armature magnetic flux is directly detected. Since the permanent magnet position, that is, the rotor position is actually detected, it is possible to drive the motor at an accurate energization timing by removing noise and increasing the detection accuracy. In other words, since the rotor position is directly detected, it is possible to easily switch from forced excitation operation to sensorless operation in a short time when the motor is started, and even when a large load change occurs, the motor can be stopped. Defects are unlikely to occur.

On the other hand, the sensorless 180-degree energization drive generally has high efficiency, low noise, and low vibration as compared with the intermittent energization drive, but there is a problem that drive control is complicated and difficult. This is because the rotor position is not directly detected, or the detection accuracy of the energization timing is poor. Therefore, when the motor is started, it takes time to shift from the forced excitation operation to the sensorless operation, or when a large load change occurs, a problem such as motor stop is likely to occur.

For example, a method of controlling the drive based on the phase difference between the motor drive voltage and the motor current is to switch the energization with the passage of time by so-called forced excitation, and control the motor current phase difference at this time, that is, the energization timing. Is. Since the control error of the motor current phase difference becomes the error of the energization timing as it is, it is necessary to strictly control the phase difference for stable driving and maintenance of the motor rotation. It is good not to do so, but there is concern about control instability when load fluctuations occur.

Further, in the method of performing predetermined high-speed calculation using the applied voltage of the stator windings, the motor current and the motor device constants to analyze the rotor position and determine the energization timing, the applied voltage and the motor current of the motor current are determined. Erroneous detection, calculation error, calculation delay, or measurement error of motor device constant,
The current situation is that the position detection accuracy deteriorates due to parameter fluctuations, etc., and the energization timing detection resolution is inferior to intermittent energization drive.

Since the energization timing in the intermittent energization drive depends on the detected induced voltage, accurate energization timing can be realized regardless of control performance. As described above, in 180-degree energization drive, accurate and strict control is required. Therefore, if load fluctuations that reduce the control margin occur, highly efficient operation cannot be realized, and motor energization The risk of causing a situation such as step-out or motor stoppage is much greater than that of intermittent energization drive.

The load fluctuation referred to here is one of the compressors used in a refrigeration cycle such as an air conditioner or a refrigerator.
Load fluctuations due to suction, compression, and discharge that occur during rotation. This load fluctuation causes vibration and noise of the compressor. Especially in a single rotary type compressor with one cylinder part, the influence of this load variation becomes large in the low rotational speed region where the rotational inertia becomes small, and the rotational speed is also greatly modulated.
Vibration and noise increase.

On the other hand, the control device described in Japanese Patent Application Laid-Open No. 2001-45789, which appropriately switches between the two drive systems to drive, selects 180-degree energization drive or intermittent energization drive according to the motor efficiency of the motor. is there. But,
No consideration is given to the easiness of starting the motor, the reliability of stable rotation continuation at the time of load change, and the measures for reducing the vibration of the compressor when the motor is used to drive the compressor.

In view of the above, it is an object of the present invention to provide a motor control device which can perform a quick start-up and can drive a load having a large load fluctuation with high efficiency and low vibration. And

[0015]

A means for solving the problems according to the present invention is to provide a 180 ° energization driving means for energizing and energizing a motor for driving a load by 180 °, and an energization pause period for the motor to set an energization angle. An intermittent energization drive means for intermittently energizing the drive at less than 180 degrees and a selection means for selecting any one drive method are provided, and the selection means selects the intermittent drive method at the time of starting. The selecting means selects the intermittent drive method at low speed and the 180-degree conduction drive method at high speed.

Further, digital position detecting means for generating a rotor position signal from the induced voltage generated in the motor coil is provided, and the intermittent energization driving means determines the energization timing to the motor based on the rotor position signal. Is. The 180-degree energization drive means determines the energization timing to the motor based on the phase difference between the motor drive voltage and the motor current flowing in the motor coil, or determines the applied voltage of the stator winding of the motor, the motor current and the motor constant. Based on this, the position of the rotor is calculated to determine the power supply timing to the motor.

With such a structure, for the motor for driving the load, one of the 180-degree energizing drive and the intermittent energizing drive is selected, and the position sensor for detecting the rotor position of the motor is not used. When the sensorless operation is performed, the intermittent energization drive is performed at the time of start-up and low speed, and the energization drive is switched to 180 degrees as the rotation speed of the motor increases.

More specifically, when the motor is started, it is started by intermittent energization drive, and is driven as it is.
After that, when the rotation speed increases and reaches the first rotation speed, the intermittent energization drive is switched to the 180-degree energization drive. On the contrary, when the rotation speed of the motor decreases to the first rotation speed, 18
The 0-degree energization drive is switched to the intermittent energization drive.

As described above, by selecting the intermittent energization drive at the time of start-up, the induced voltage generated in the motor coil can be detected in a short time, so that it is possible to shift to the sensorless operation. As a result, quick startup can be performed. By switching to 180-degree energization drive after starting, it is possible to drive the motor by taking advantage of the high efficiency, low noise, and low vibration of this drive system.

Then, the second rotation speed higher than the first rotation speed is set, and when the rotation speed of the motor is less than the first rotation speed, the selecting means selects the intermittent energization drive method to set the first rotation speed. When the rotation speed is less than the second rotation speed, the 180-degree energization drive method is selected, and when the rotation speed is more than the second rotation speed, the intermittent conduction drive method is selected. In the 180-degree energization drive as the rotation speed increases, when the sine wave drive is performed, the resolution of the sine wave becomes low and the control accuracy may deteriorate. Therefore, by switching to intermittent energization drive at high speed rotation, the rotor position can be detected reliably and stable drive can be performed, so the reliability of drive control can be improved.

As the load driven by the motor, there is a compressor used in an air conditioner or a refrigerator, which has a characteristic that load fluctuations occur periodically, and the motor torque corresponds to the load fluctuations of the compressor during intermittent energization drive. Torque control means for controlling the torque of the motor is provided. At low speeds when intermittent energization drive is performed, it is more likely to be affected by load fluctuations than at high speeds. Therefore, by performing torque control so that load fluctuations during one rotation and motor torque match, fluctuations in rotation speed and vibrations are suppressed. Can be suppressed.

The first rotation speed at the time of switching from the intermittent energization drive to the 180-degree energization drive is the rotation speed at which the vibration of the compressor becomes equal to or less than the specified value without torque control.
By setting in this way, it is possible to reduce the control load at the time of 180-degree energization drive in which torque control is difficult to implement.

In the torque control means, when the intermittent energization drive is switched to the 180-degree energization drive, the torque control is stopped. That is, when the intermittent energization drive in which the torque control is performed is suddenly switched to the 180-degree energization drive in which the torque control is not performed, a problem such as an increase in vibration due to load fluctuation may occur, and the control may become unstable. Therefore, the control can be stabilized by prohibiting the torque control for a predetermined period before the switching.

When the 180-degree energization drive is switched to the intermittent energization drive, the torque control is temporarily stopped and then the torque control is performed, whereby the control can be stabilized in the same manner as described above. In addition, by setting a third rotation speed lower than the first rotation speed, torque control is performed when the rotation speed of the motor is lower than the third rotation speed, and torque control is not performed when the rotation speed is equal to or higher than the third rotation speed. Good.

Here, the torque control means selects a torque pattern according to the mechanical position of the rotor from among a plurality of torque patterns set on the basis of the number of rotations of the motor or the load state of the motor to perform torque control. It is a thing.

Then, the mechanical position information of the rotor at the time of switching from the intermittent energization drive to the 180 ° energization drive is held, and based on the mechanical position information held at the time of switching from the 180 ° energization drive to the intermittent energization drive. Torque control. As a result, it is not necessary to determine the mechanical position of the rotor again after switching the drive system, and torque control can be started immediately. Therefore, it is possible to always reduce the fluctuation of the rotation speed and reduce the vibration.

[0027]

FIG. 1 shows a motor control device according to an embodiment of the present invention. In FIG. 1, 1 is a motor, 2 is an inverter circuit that drives the motor 1, 3 is a converter circuit that rectifies an AC power supply 4 and supplies DC power to the inverter circuit 2, and 5 is a microcomputer for driving and controlling the motor 1. Alternatively, 6 is a control circuit including a DSP, 6 is a drive system selection unit that determines the drive system according to the state of the motor 1 or an external instruction, and 7 is for intermittently energizing the motor 1 with an energization pause period of less than 180 degrees of energization. The intermittent energization drive unit 8 controls the energization timing, the drive voltage (PWM duty) reference value, and the like. The energization timing is set and the drive voltage (PWM duty) reference is provided because the motor 8 energizes the motor 1 by 180 degrees. Controls such as setting values 1
80 degree energization drive unit, 9 is a PWM creation / phase distribution unit that creates and outputs a PWM signal for driving each drive element of the inverter circuit 2 for each drive element /
2 is a resistor that creates a reference voltage, 11 is a comparator that compares the induced voltage waveform of the motor 1 with a reference voltage that is ½ of the DC voltage, and 12 is a motor current detection unit that detects the current flowing through the motor coil of the motor 1. is there. Note that the power supply to the inverter circuit 2 may use so-called PAM control, which is a variable power supply method that has been performed in recent years.

The AC voltage of the commercial power source is input from the AC power source 4 to the converter circuit 3, and the converter circuit 3 including a reactor, a rectifying circuit, and a smoothing circuit rectifies the AC voltage into a DC voltage, and a ripple component of the DC voltage. Is smoothed, and the rectified DC voltage is applied to the inverter circuit 2. In the inverter circuit 2, six driving elements, which are semiconductor switching elements, are connected in a three-phase bridge shape,
The drive voltage from the inverter circuit 2 is output to the three-phase brushless motor 1.

The drive method selection unit 6 selects a drive method such as intermittent energization drive or 180 degree energization drive of the motor 1 according to the state of the motor 1 or an external instruction. The state of the motor 1 includes the number of revolutions, efficiency, load state, disturbance state, and the like. For example, intermittent energization drive may be performed at low speed, 180 degree energization drive at high speed, or intermittent energization drive at light load and 180 degree energization drive at high load. The intermittent energization drive may be switched when a disturbance that makes it difficult to continue the 180-degree energization drive. Furthermore, the operator can switch the drive system by an external switch. For example, when driving at night, emphasis is placed on noise reduction, and switching is performed when 180-degree energization drive is desired.

The sensorless position detecting means of intermittent energization drive is roughly divided into an analog type and a digital type.
There are two methods. In addition, what is shown in FIG. 1 is an example of a case where a digital method is used. In the analog method, an analog filter circuit consisting of a capacitor and a resistor is inserted in the position detection input section that inputs the motor terminal voltage waveform, and the waveform is shaped into a sine wave and input to the comparator, and compared with the virtual midpoint potential to detect the position. Generating a signal. Because of this filter circuit, it is 90 degrees out of phase with the actual induced voltage waveform.

In the digital system, the waveform of the induced voltage of the motor is input to the comparator 11 as it is in the form of a PWM-switched pulse, and compared with the reference voltage of 1/2 of the DC voltage created by the resistor 10 to detect the position. Generate a signal. However, since the induced voltage waveform does not appear when the PWM waveform is off, processing is performed inside the control circuit 5 so that it can be detected only when it is on. Based on the detected position signal, the actual output timing of the PWM waveform is determined, and the advance angle (field weakening) control is performed.

With such advance angle control, it is possible to achieve high efficiency operation and expansion of the high rotational speed range. Further, since there is no filter circuit, the detection accuracy is high, there is no phase delay, and the advance angle (field weakening) control becomes easy. Further, the position can be detected even in a low speed range where the induced voltage is small, and the sensorless operation can be performed from a low rotation speed at the time of starting. As a result, the start-up current is reduced, so that it is possible to prevent the drive element such as the transistor of the inverter circuit 2 from being destroyed by the excessive current, and the reliability of the drive control can be improved.

In a sensorless drive system of 180-degree energization drive as shown in FIG. 1, which is a drive control based on a phase difference between a motor drive voltage and a motor current, energization is switched over time by so-called forced excitation. Then, by changing the motor drive voltage, the motor current phase difference between the motor current detected by the motor current detection means 12 and the motor drive voltage, that is, the energization timing is controlled. Details thereof are disclosed in Japanese Patent Laid-Open No. 2001-54297.

In order to improve efficiency and suppress torque fluctuation, vibration, and noise, it is desirable that the 180-degree energization drive is a sinusoidal waveform that can realize a smooth change of the drive waveform. The drive waveform of the intermittent energization drive may be any drive waveform as long as the energization angle is less than 180 degrees, the energization period is provided in the drive waveform, and the induced voltage generated during that period can be detected. For example, if the 120-degree energization drive is used, it is a complete two-phase energization and rectangular wave energization is possible, so there is an advantage that it is easy to create a drive waveform to be supplied to each phase.

The drive waveforms in each drive method are shown. Figure 2
Is a drive waveform of a rectangular wave 120 ° energization, which is an example of intermittent energization drive, and FIG. 3 is a drive waveform of a sine wave energization, which is an example of a 180 ° energization drive. 2 and 3 are waveform diagrams showing signals for driving the drive elements of the inverter circuit 2 (PWM creation / output of each phase distribution unit 9) as analog values for each coil terminal, during the actual energization period. The PWM drive waveform is PWM-chopped at several to several tens of kHz, and the duty of the PWM drive signal is changed so as to reach the target rotation speed. By changing the duty, the voltage or current applied to the motor 1 is changed, and the rotation speed and torque are controlled.

Here, in the sensorless operation, it is difficult to detect the stop position, so that the motor starting method is a major problem. Japanese Patent Application Laid-Open No. 2001-54295 discloses a 180-degree energization drive system starting method in which drive control is performed based on a phase difference between a motor drive voltage and a motor current. As shown in FIG. 4, the motor drive voltage is gradually increased from the low voltage state, and the stable start state is detected depending on whether the phase difference between the motor drive voltage and the motor current is stable or unstable. Therefore, it takes about 3 to 10 seconds to complete the startup.

Next, as a method for starting the intermittent energization drive method, a method is generally used in which the motor 1 is first started by a forced excitation operation, and when the induced voltage can be detected, a sensorless operation is started. FIG. 5 shows a motor current waveform at the time of starting the intermittent energization drive. According to this method, the starting voltage can be detected and the sensorless operation can be performed within a short time after the start of rotation of the motor, so that the time required to complete the starting is about 1 second.

As described above, in the intermittent energization drive method, the time required to complete the start-up can be shortened, the start-up current can be reduced, and the reliability of the drive element of the inverter circuit 2 can be improved. Therefore,
The drive system selection unit 6 selects the intermittent energization drive at the time of start-up and promptly starts up, and after completion of the start-up, controls to switch to 180-degree energization drive. The motor current waveform at this time is shown in FIG.

Next, another sensorless drive system in the 180-degree conduction drive system will be described. As shown in FIG. 7, motor current detection means 13a and 13b for detecting the current flowing through the motor coil of the motor 1 are provided. As in FIG. 1, a digital system is used as a sensorless drive system for intermittent energization drive. In this sensorless drive method of 180-degree energization drive, a predetermined high speed calculation is performed using the applied voltage of the stator winding, the motor current detected by the motor current detection means 13a and 13b, and the device constant of the motor 1 to perform the rotor position. Is analyzed and the energization timing is determined.

FIG. 8 shows a motor current waveform at the time of starting the 180-degree energization drive in this system. First, the motor 1 is started by the forced excitation operation, the rotation speed is gradually increased, and when the rotation speed reaches a predetermined value, the sensorless operation is started. In this method, the time required to complete the startup is longer than in the intermittent energization drive method. Therefore, the drive method selection unit 6 selects the intermittent energization drive at the time of startup, and switches to the 180-degree energization drive after completion of the startup. As a result, the start-up current can be promptly reduced, the start-up current can be reduced, and the reliability of the drive element of the inverter circuit 2 can be improved. The motor current waveform at the time of startup at this time is the same as in FIG.

Next, as the load driven by the motor 1,
2. Description of the Related Art There is a compressor having a characteristic of having a periodicity with a load variation during one rotation. A compressor generally used in an air conditioner, a refrigerator, etc. is an important component of a refrigeration cycle, and compresses a refrigerant to bring it into a high temperature and high pressure state for heat exchange. Usually, this compression operation is roughly divided into three strokes. First, there is a suction stroke that fills the refrigerant in the cylinder inside the compressor, and then there is a compression stroke that compresses the refrigerant in the cylinder. There is a discharge stroke that discharges to the outside of the compressor. In the compressor, load fluctuations during one rotation occur periodically according to each stroke.

The compressor may be a rotary type, a reciprocating type, a scroll type, or the like, depending on the compression mechanism. Among them, the rotary method is often adopted because it has a simple structure, has a small number of parts, is low in cost, and has a high compression efficiency due to the structure of the cylinder portion, and it is easy to achieve high efficiency, as compared with other methods. . However, in this rotary system, a rotary piston, which is eccentric to perform a compression operation, rotates inside the cylinder to perform suction, compression, and discharge strokes. 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.

To solve this problem, a twin rotary system has been put to practical use in which two cylinder parts are provided and the rotations of the rotary pistons are shifted by 180 degrees so as to cancel out the mutual vibrations. However, compared to the single rotary system with one cylinder, there are problems that the structure is complicated, the cost is increased, and the efficiency is reduced.

On the other hand, the single rotary system has a high efficiency, but in a low rotational speed region where the rotational inertia is small, the rotational speed fluctuation and vibration become very large, and the motor current waveform is greatly disturbed. Therefore, the control accuracy and the position detection accuracy in 180-degree energization drive deteriorate, and highly efficient operation cannot be realized. Furthermore, the risk of causing a situation such as step-out of energization of the motor or stop of the motor becomes much greater than that of intermittent energization driving such as 120-degree energization driving. Since the energization timing in the intermittent energization drive depends on the detected induced voltage, regardless of the control performance,
Accurate energization timing can be realized at any time.

Therefore, in the case of driving a compressor which has a large load fluctuation and in which the rotation speed fluctuation is likely to occur in a low rotation range, in particular, a single rotary type compressor, the drive method selection section 6 is used.
At the time of start-up and the rotation speed of the motor 1 is a predetermined rotation speed (first
At low speeds less than the number of revolutions α, select intermittent energization drive,
At a high speed equal to or higher than the predetermined rotation speed α, control is performed to switch to 180-degree energization drive. By performing such control,
It is possible to realize highly efficient and highly reliable drive control.

The control circuit 5 stores an energization method selection table as shown in FIG.
Selects a drive method from this table according to the rotation speed of the motor 1. For example, at start-up and at a low speed of less than 3000 rpm, intermittent energization drive is performed and 3000 rpm
At the above high speed, 180-degree energization drive is performed. here,
The predetermined rotation speed α is set to 3000 rpm, in general, when the motor 1 drives a single rotary compressor, the rotation inertia becomes large in a high speed range of about 3000 rpm or more, and the rotation speed fluctuation and vibration are smaller than those in the low speed range. This is because it becomes smaller, so that 180-degree energization drive in sensorless operation can be performed without problems.

By the way, when the motor 1 drives a single rotary type compressor, in a low speed range of less than 3000 rpm, the rotational inertia is small, and fluctuations in rotation speed and vibration are greater than in the high speed range. Therefore, in the low speed range, a drive method has been proposed in which the motor torque is controlled to suppress fluctuations in rotation speed and vibrations. This method increases the motor torque at the rotor position where the load torque is large, and conversely reduces the motor torque at the rotor position where the load torque is small to keep the rotor speed constant during one rotation to reduce vibration. It is what makes me.

In the torque control in the intermittent energization drive, a torque pattern stored in advance in a storage means such as a memory so as to correspond to the load torque fluctuation due to the suction stroke and the compression stroke of the compressor is used, depending on the rotor position. Since the output voltage of the inverter circuit 2 can be changed to control the motor torque during one rotation, it can be easily implemented. The torque control in the 180-degree energization drive is difficult to implement because the control accuracy and the position detection accuracy deteriorate due to the load torque fluctuation, and the load of the arithmetic processing of the microcomputer in the control circuit 5 increases.

Therefore, at a low speed less than a predetermined rotation speed (first rotation speed), intermittent energization drive is selected, and torque control is performed to match the load fluctuation during one rotation of the compressor with the motor torque. It is possible to reduce fluctuations in rotation speed, reduce vibration of the compressor, and reduce noise.

The torque control in the 120-degree energization drive, which is an example of the intermittent energization drive, will be described. When controlling a single rotary type compressor having a large load fluctuation during one rotation as shown in FIG. 10 using a plurality of torque patterns,
The data of the torque compensation amount (torque pattern) shown in FIG. 11 for each mechanical position of the rotor is stored in the ROM of the control circuit 5 in advance.
It is stored in storage means such as. When the motor torque is controlled by the PWM duty, the data to be stored in the ROM is the PWM duty compensation amount.
The duty is compensated, and the PWM duty is compensated so that the current is reduced in a section where the load torque is small. This compensation amount is determined by making adjustments through experiments and simulations so that the vibration and noise of the compressor are reduced and the efficiency of the motor 1 is increased. Also, the amount of compensation must be changed according to the load. Therefore, the rotation speed is divided into a plurality of regions, the torque pattern corresponding to the detected rotation speed is read from the storage means, and the PWM duty is compensated by using the torque pattern.
The torque control performance can be improved.

Specifically, a predetermined PWM duty compensation amount is read from the storage means according to the state corresponding to the mechanical position of the rotor, and the PWM for each mechanical position of the rotor is read.
Correct the duty. Here, the state is shown in FIG.
As shown in Fig. 1, one rotation of the rotor is divided for each energization mode, that is, for each commutation.
It is divided and has 12 states from state 0 to state 11. However, state n and state n + 6 (n:
The energization modes (integer 0 to 5) are the same, the electrical positions are the same, but the mechanical positions are different.

Here, the predetermined number of revolutions (first number of revolutions) for switching between the intermittent energization drive and the 180-degree energization drive is the number of revolutions when the vibration of the compressor becomes a predetermined value or less without torque control. It should be set to. FIG. 13 shows the rotational speed-vibration characteristics of the single rotary type compressor driven with intermittent energization, with and without torque control. This is the result of measuring the vibration amplitude in the rotation direction where the largest vibration appears. Considering the reliability of the piping of the outdoor unit of the air conditioner, set the vibration of the compressor to 100%.
The rotation speed is 3000 rpm in order to keep it below μm.
It is understood that it is necessary to perform torque control at less than 3000 rpm, and there is no problem at 3000 rpm or more without torque control.

Therefore, the control circuit 5 is 3000 rp
If it is less than m, emphasis is placed on low vibration, torque control is performed by intermittent energization drive, torque control is not performed at 3000 rpm or more,
180 degree energization drive is performed with an emphasis on high efficiency and low noise.

Although the drive system is switched at the above-mentioned predetermined number of revolutions, the intermittent current-carrying drive with torque control during motor acceleration is not suddenly switched to the 180-degree current-carrying drive, but the torque control is once performed without torque control in the intermittent current-carrying drive. The control is stabilized by switching to, and then switching to 180 ° energization drive. That is, from the intermittent energization drive to 1
It is advisable to prohibit the torque control for a predetermined time before switching to the 80-degree energization drive. That is, the timing for switching the drive system is known in advance, and the torque control is stopped for a predetermined time when a certain time based on this timing is measured from the time of start-up. Alternatively, the rotation speed (first rotation speed) when switching the drive system is set to be larger than the switching rotation speed (third rotation speed) of the torque control, and for example, torque control in intermittent energization drive at 3000 rpm as the third rotation speed. Alternatively, the torque control may be switched to without torque control, and the intermittent energization drive may be switched to the 180-degree energization drive at 3200 rpm as the first rotation speed.

Also, when the 180-degree energization drive is switched to the intermittent energization drive at the time of deceleration of the motor, the 180-degree energization drive is temporarily switched from the 180-degree energization drive to the torque instead of the abrupt change from the 180-degree energization drive to the intermittent energization drive with torque control. Control is stabilized by switching to intermittent energization drive without control and then switching from no torque control to with torque control in intermittent energization drive. For example, immediately after switching from 180-degree energization drive to intermittent energization drive, torque control may be prohibited once, and torque control may be permitted after a predetermined time has elapsed. Alternatively, the rotation speed (first rotation speed) when switching the drive system is set to be larger than the switching rotation speed (third rotation speed) for torque control, and for example, 180 ° energization drive is switched to intermittent energization drive at 3200 rpm, 3000 rpm In the intermittent energization drive, it is possible to switch from no torque control to with torque control. FIG. 14 shows a selection table of the drive system and the torque control with respect to the rotation speed. Drive system selection unit 6
Selects the drive system and the presence / absence of torque control according to this table.

Further, the drive system selecting section 6 determines that the motor 1 is accelerated to a predetermined rotation number α or more, and the intermittent energization drive is started from 1
When switching to the 80-degree energization drive, the energization phase of the 180-degree energization drive after the switching is determined according to the energization mode of the intermittent energization drive at the time of switching. As a result, when the drive system is switched, the phase information at the time of intermittent energization drive is inherited, and it becomes possible to stably shift to the next drive system with an accurate energization phase. At this time, not only the energization phase information but also the mechanical position information of the rotor determined by the rotor mechanical position determining means of the intermittent energization drive unit 7 is inherited, and is kept held even after switching to the 180-degree energization drive. . After that, the motor 1 decelerates to less than the predetermined rotation speed α, and when the 180-degree energization drive is switched to the intermittent energization drive, the energization of the intermittent energization drive after the switching is performed according to the energization phase of the 180-degree energization drive at the time of switching. Determine the mode.
The phase information at the time of 180-degree energization drive is inherited, and it becomes possible to stably shift to the next drive method in the accurate energization mode. Further, not only the energization phase information but also the rotor mechanical position information held by the 180-degree energization drive unit 8 is taken over, and the torque control in the intermittent energization drive is performed using this rotor mechanical position information.

This specific example will be described with reference to FIGS. FIG. 12 shows the relationship between the state and the mechanical angle and the electrical angle in the 120-degree energization drive, and each energization mode. FIG. 15 shows a signal (a PWM creation / each phase distribution unit) for driving the drive element of the inverter circuit 2. 9) is a waveform diagram showing the state of energization of the U-phase coil terminal as an analog value, and shows the relationship between the energization phase of 180-degree energization drive and the U-phase drive voltage waveform. For example, the 120-degree energization drive, which is an example of the intermittent energization drive, is as shown in FIG.
Energization mode is 0, 1, ...
It is a method of switching in order of ..., 5, 0, ....

At the time of switching from 120-degree energization drive to 180-degree energization drive, the current energization phase is calculated from the energization mode at the time of switching. For example, at the timing of switching from energization mode 1 to 2 in 120-degree energization drive, 12
If the energization mode 1 of 0-degree energization drive is switched to the sine wave waveform of 180-degree energization drive, the energization phase is 120 degrees, and sinusoidal wave data can be set using this energization phase of 120 degrees.

At this time, not only the energization phase information but also the rotor mechanical position information determined by the rotor mechanical position determining means of the intermittent energization drive unit 7 is inherited, so the mechanical position determination flag is used. If the state at the time of switching is state 1, the mechanical position determination flag is set to High,
If the state at the time of switching is the state 7, the mechanical position determination flag is set to Low. 180 degree energizing drive unit 8
When the energization phase is 0 degree, the mechanical position determination flag is inverted to keep the rotor mechanical position information, as shown in FIG.

Thereafter, when the 180-degree energization drive is switched to the 120-degree energization drive, the energization mode of the 120-degree energization drive after the switching is determined according to the energization phase of the 180-degree energization drive at the time of switching. For example, 18 at an energizing phase of 90 degrees
Assuming that the 0-degree energization drive is switched to the 120-degree energization drive, energization may be started from the energization mode 1 in the 120-degree energization drive after the drive method switching from FIG. At this time, if the mechanical position determination flag is High, the state 1 is set, and if the mechanical position determination flag is Low, the state 7 is set.
The torque control can be started without performing the mechanical position determination of the rotor again.

Further, when the sensorless motor 1 is driven by a sine wave which is an example of 180-degree energization drive, the control circuit 5
Outputs the sine-wave modulated PWM waveform to the inverter circuit 2. Here, during high-speed driving, the resolution of the sine wave becomes low, and the current is distorted with respect to the sine wave. Therefore, the control accuracy may deteriorate because the control cannot follow the load fluctuation. Therefore, a second rotation speed higher than the first rotation speed is set, and control is performed so that the 180-degree energization drive is switched to the intermittent energization drive at the second rotation speed. That is, it is started by intermittent energization drive, and the first rotation speed is 3000 rpm.
When the speed is lower than less than 1, the intermittent energization drive is performed. 1 at medium speed drive of 3000 rpm or more and less than the second rotation speed of 6000 rpm
It is advisable to carry out energization at 80 degrees and return to intermittent energization at high speeds of 6000 rpm or higher. FIG. 16 shows a drive system selection table for the number of rotations. The drive system selection unit 6 selects a drive system according to this table.
At this time, the torque control as described above may be performed when the intermittent energization drive at low speed is performed.

Since the control in the drive system selection section 6 can be realized by the software of the control circuit 5, there is no problem such as cost increase. Further, the motor 1 is used for driving a compressor of an air conditioner or a refrigerator, and torque control is performed by intermittent energization drive at low speed, so that the vibration of the compressor can be reduced. Therefore, it is not necessary to allow the compressor piping to have a margin as a measure against vibration. That is, the outdoor unit and the refrigerator can be made compact.

The present invention is not limited to the above embodiment, and it goes without saying that many modifications and changes can be made to the above embodiment within the scope of the present invention. Each of the control methods described above may be used alone, or any method may be combined to further improve the control performance.

[0064]

As is apparent from the above description, according to the present invention, when the motor is driven without a sensor, the intermittent energization drive is performed at the start, and then the 180-degree energization drive is performed, so that the motor can be reliably driven in a short time. Can be started, and highly efficient and low vibration operation can be performed. for that reason,
Since the start-up current can be reduced, it is possible to prevent the drive element of the inverter circuit, which is likely to occur at the time of start-up, from being destroyed, and to realize a highly reliable control device.

Further, even for a load having a large load fluctuation such as a compressor, by selecting the drive system and controlling the torque according to the motor speed, the fluctuation of the speed and the vibration of the compressor can be reduced. It is possible to realize a highly efficient and highly reliable control device.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a motor control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a drive waveform of intermittent energization drive.

FIG. 3 is a diagram showing a drive waveform of 180-degree conduction drive.

FIG. 4 is a diagram showing a motor current waveform at the time of starting the 180-degree conduction drive.

FIG. 5 is a diagram showing a motor current waveform at the time of starting the intermittent energization drive.

FIG. 6 is a diagram showing a motor current waveform at startup in the present embodiment.

FIG. 7 is a block diagram of a motor control device of another embodiment.

FIG. 8 is a diagram showing a motor current waveform at the time of start-up in another method of 180-degree conduction drive.

FIG. 9 is a diagram showing an energization method selection table.

FIG. 10 is a diagram showing a relationship between a load torque and a torque pattern during torque control.

FIG. 11 is a diagram showing an example of a torque pattern.

FIG. 12 is a diagram showing a relationship between a conduction mode, a mechanical angle, and an electrical angle with respect to a 120-degree conduction drive state.

[Fig. 13] Rotational speed of a single rotary type compressor-
Vibration characteristic diagram

FIG. 14 is a diagram showing an energization method and a torque control presence / absence selection table.

FIG. 15 is a diagram showing a relationship between a conduction phase of 180-degree conduction drive and a U-phase drive voltage waveform.

FIG. 16 is a diagram showing another energization method selection table.

[Explanation of symbols]

1 brushless motor 2 Inverter circuit 3 converter circuit 4 AC power supply 5 control circuit 6 Drive system selection section 7 Intermittent current drive unit 8 180 degree energizing drive 9 PWM creation unit / Phase distribution unit 10 Reference voltage resistance 11 comparator 12 Motor current detection means

Claims (19)

[Claims] 1. A 180-degree energizing driving means for energizing a motor for driving a load by 180 degrees, and an intermittent energizing driving means for intermittently energizing the motor with a de-energized period and an energization angle of less than 180 degrees. And a selecting means for selecting any one of the driving methods, and the selecting means selects the intermittent driving method at the time of starting. 2. A 180-degree energization driving means for energizing a motor for driving a load by 180 degrees, and an intermittent energization driving means for intermittently energizing the motor with an energization pause period of less than 180 degrees. And a selecting means for selecting one of the driving methods, wherein the selecting means selects the intermittent driving method at a low speed and the 180-degree conduction driving method at a high speed. 3. A first rotation speed is set as the rotation speed of the motor when switching between the intermittent conduction drive method and the 180-degree conduction drive method, and the selection means sets the rotation speed of the motor to the first rotation speed. 3. The motor control device according to claim 1, wherein the intermittent energization drive system is selected when the rotational speed is lower than the predetermined number, and is switched to the 180-degree energization drive system when the rotational speed is equal to or higher than the first rotation speed. 4. A second rotation speed that is higher than the first rotation speed is set, and the selection means selects the intermittent energization drive method when the rotation speed of the motor is less than the first rotation speed and is equal to or higher than the first rotation speed. When the speed is less than the second speed, select the 180 degree energization drive method,
4. The motor control device according to claim 3, wherein the intermittent energization drive method is selected when the rotational speed is equal to or higher than the second rotation speed. 5. A torque control of a motor such that a load driven by the motor is a compressor having a characteristic that the load fluctuates periodically, and the motor torque corresponds to the load fluctuation of the compressor during intermittent energization drive. The motor control device according to any one of claims 1 to 4, further comprising torque control means for performing the above. 6. The number of revolutions when switching from the intermittent energization drive to the 180-degree energization drive is set to a number of revolutions at which the vibration of the compressor becomes equal to or less than a specified value without performing torque control. 5. The motor control device according to item 5. 7. The motor control device according to claim 5, wherein the torque control means stops the torque control when the intermittent energization drive is switched to the 180-degree energization drive. 8. The motor control device according to claim 5, wherein when the 180-degree energization drive is switched to the intermittent energization drive, the torque control means performs the torque control after temporarily stopping the torque control. 9. A third rotation speed lower than the first rotation speed is set, and the torque control means performs torque control when the rotation speed of the motor is lower than the third rotation speed, and when the rotation speed is equal to or higher than the third rotation speed. The motor control device according to claim 5 or 7, wherein torque control is not performed. 10. The torque control means selects a torque pattern according to the mechanical position of the rotor from a plurality of torque patterns set based on the rotational speed of the motor or the load state of the motor to perform the torque control. The motor control device according to any one of claims 5 to 9, wherein: 11. The torque control means holds rotor mechanical position information when switching from intermittent energization drive to 180-degree energization drive, and retains it when switching from 180-degree energization drive to intermittent energization drive. The motor control device according to claim 10, wherein torque control is performed based on the target position information. 12. A digital position detecting means for generating a rotor position signal from an induced voltage generated in a motor coil is provided, and the intermittent energization driving means determines an energization timing to the motor based on the rotor position signal, The motor control according to any one of claims 1 to 11, wherein the 180-degree energization drive means determines the energization timing to the motor based on the phase difference between the motor drive voltage and the motor current flowing through the motor coil. apparatus. 13. A digital position detecting means for generating a rotor position signal from an induced voltage generated in a motor coil is provided, and the intermittent energization driving means determines an energization timing to the motor based on the rotor position signal, 12. The 180-degree energization driving means determines the energization timing of the motor by calculating the position of the rotor based on the voltage applied to the stator winding of the motor, the motor current and the motor constant. The motor control device according to any one of 1. 14. A motor for driving a load, comprising 18
Without using a sensor for detecting the rotor position of the motor, a 180-degree energization drive for 0-degree energization drive and an energization pause period are provided and an energization angle is less than 180 degrees to select one of the intermittent energization drive methods. A control method for driving and controlling the motor, wherein intermittent energization drive is performed at the time of startup and at a low speed, and 180
A motor control method characterized by switching to energized drive every time. 15. The torque control for controlling the motor torque is performed so that the motor torque corresponds to the load fluctuation during the intermittent energization drive at a low speed.
4. The motor control method described in 4. 16. The motor control method according to claim 15, wherein torque control is not performed for a predetermined time period before switching from intermittent energization drive to 180-degree energization drive. 17. The motor control method according to claim 15, wherein when the 180-degree energization drive is switched to the intermittent energization drive, torque control is not performed for a predetermined time. 18. An air conditioner in which the motor control device according to any one of claims 1 to 13 is used for drive control of a motor that drives a compressor of a refrigeration cycle. 19. A refrigerator characterized in that the motor control device according to any one of claims 1 to 13 is used for drive control of a motor for driving a compressor of a refrigeration cycle.