JP2008022685A - Motor controller and compressor driving device equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller highly efficiently controlling a motor connected to a load having large variation of a load torque without using a sensor for sensing a rotor position, and having less operation quantity in control. <P>SOLUTION: The motor controller is provided with an inverter circuit 3 and a control means. The control means has a phase difference detecting unit 8 for detecting a difference in phase between a motor driving voltage and a motor winding current on the basis of a DC current flowing through the inverter circuit 3; a PWM data creating means for creating PWM data for 180-degree conduction system in response to the phase difference; a torque fluctuation correction value table 16 for previously storing a torque fluctuation correction value corresponding to a mechanical angle of the motor; and a PWM waveform signal forming means for forming a PWM waveform signal to be outputted to the inverter circuit 3 from the PWM data (output from the PWM data creating unit 15), and the torque fluctuation correction value (output from the torque correction data creating unit 18). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor control device that drives and controls a synchronous motor such as a brushless motor having a rotor on which a permanent magnet is mounted, and a compressor driving device including the motor control device.

  In the motor driving method, the 180-degree energization driving method refers to a method of controlling the driving of the synchronous motor without providing an energization stop period in the waveform of the motor winding current. Normally, in this method, the phase difference between the motor driving voltage and the motor winding current is controlled.

  In Patent Document 1, when a synchronous motor is controlled and driven by a 180-degree energization driving method, a phase difference between an AC voltage and an AC current is detected based on a DC current flowing through a motor driving inverter circuit, and the detected AC is detected. It has been proposed to use an inverter device that performs inverter control according to a voltage / current phase difference (phase difference between a motor drive voltage and a motor winding current).

  In Patent Document 2, as a technique for improving motor efficiency in the 180-degree energization driving method, a motor connected to a load having a large variation in load torque is controlled with high efficiency without using a sensor for detecting the rotor position. Motor control devices have been proposed.

The motor control device is “a control device for controlling a synchronous motor having a plurality of phase coils, wherein a first phase current for detecting a specific phase of the plurality of phases is detected. Detection means; second detection means for detecting the mechanical angle of the rotor of the synchronous motor based on the pulsation of the current; and for generating voltage data before correction in each phase for each phase. And a plurality of switching elements, and on the basis of the control data, the conduction of each of the switching elements is controlled, the energization means for energizing each of the coils, and the voltage data corresponding to the mechanical angle Including a first storage means for storing a first correction value for correcting the current and a control means for controlling the energization means, wherein the control means is predetermined for the voltage of the specific phase. Based on phase The first calculation means for calculating the ratio between the integrated values of the currents of the specific phase in the same length period, and the ratio calculated by the first calculation means is controlled to a target ratio As described above, based on the second calculation means for calculating the second correction value for correcting the voltage data, the voltage data of each phase, the first correction value, and the second correction value. A motor control device including a third calculation means for calculating the control data for each phase, or a control device for controlling a synchronous motor including a plurality of phase coils, It includes a plurality of switching elements, controls conduction of each switching element based on control data, detects energization means for energizing each coil, and current in any one of the plurality of phases First detecting means for Second detection means for detecting the mechanical angle of the rotor of the synchronous motor based on pulsation of DC current supplied to the energization means, and third detection means for detecting the DC current; Creation means for creating voltage data before correction in each phase for each phase, and first storage for storing a first correction value corresponding to the mechanical angle and correcting the voltage data And a control means for controlling the energization means, wherein the control means is configured to control the specific phase in a period of the same length based on a predetermined phase in the voltage of the specific phase. A first calculator for calculating a ratio between the integrated values of the current; and a second calculator for correcting the voltage data so as to control the ratio calculated by the first calculator to a target ratio. Second calculation for calculating the correction value Output means, and third calculation means for calculating the control data for each phase based on the voltage data of each phase, the first correction value, and the second correction value, It is a motor control device.
JP 2005-160149 A JP 2004-274841 A

  However, the devices proposed in Patent Document 1 and Patent Document 2 described above have the following problems.

  The motor control device using the inverter device proposed in Patent Document 1 is a device that can be controlled under the same rotation conditions. In the absence of special control, in order to drive the motor at the same rotational speed, the load connected to the synchronous motor needs to be constant (small load torque fluctuation). When a synchronous motor connected to a load having a large load torque fluctuation is controlled, the rotational speed of the rotor fluctuates due to the influence of the load torque. When the rotational speed of the rotor varies, the phase difference information varies greatly from the assumed value. If the phase difference information largely fluctuates from an assumed value, the motor control device cannot control the synchronous motor in response to the load torque fluctuation. When the synchronous motor cannot be controlled in response to the load torque fluctuation, the generated torque of the synchronous motor decreases. Eventually, the phase difference information deviates from the range in which the motor can be driven, the motor driving itself becomes impossible, and the synchronous motor stops (hereinafter referred to as “motor step-out”).

  The motor control device proposed in Patent Document 2 can control a motor connected to a load with large fluctuations in load torque with high efficiency without using a sensor for detecting the rotor position. However, there is a problem that the calculation amount of the control means (for example, a microcomputer) increases.

  The motor control device using the inverter device proposed in Patent Document 1 drives the motor by the 180-degree energization drive method even if the control device (for example, a microcomputer) provided in the inverter device has a low computing capacity. For example, as the synchronous motor is driven at a higher speed, the time required for the calculation becomes longer. In addition, the amount of calculation as in the motor control device proposed in Patent Document 2 increases. If the control method is adopted, the time required for the calculation of the control device becomes long, the calculation does not end within a predetermined time corresponding to the rotation speed, and there is a possibility that the motor cannot be driven.

  In view of the above-described problems, the present invention can control a motor connected to a load with large fluctuations in load torque without using a sensor for detecting the rotor position with high efficiency, and the amount of calculation in the control It is an object of the present invention to provide a motor control device with a small amount and a compressor driving device including the motor control device.

  In order to achieve the above object, a motor control device according to the present invention includes a motor drive inverter circuit that converts DC power into AC power, and a control device that controls the inverter circuit by a phase difference control method, and the control The apparatus creates phase difference detection means for detecting the phase difference between the motor drive voltage and the motor winding current based on the direct current flowing through the inverter circuit, and PWM data for the 180-degree energization drive method according to the phase difference. Each switching element of the inverter circuit from the PWM data creating means, the storage means for storing the torque fluctuation correction value corresponding to the mechanical angle of the motor in advance, the 180-degree energization drive system PWM data and the torque fluctuation correction value And a PWM waveform signal generating means for generating a PWM waveform signal to be output.

  According to such a configuration, the motor torque of the motor is increased / decreased according to the torque fluctuation correction value, and torque control according to the load torque of the motor is possible. The fluctuations in the number of rotations during one rotation can be suppressed. Therefore, it is possible to control a motor connected to a load having a large variation in load torque with high efficiency. Furthermore, the amount of calculation in the control can be reduced as compared with the motor control device proposed in Patent Document 2.

  In the motor control device having the above-described configuration, for example, the PWM waveform signal generating means may generate the PWM waveform signal based on an added value of the 180-degree energization drive system PWM data and the torque fluctuation correction value.

  Further, the control device has means for creating a PWM waveform signal for intermittent energization drive system, and the PWM waveform signal for intermittent energization drive system is not used at the start of the motor without using the torque fluctuation correction value. It is desirable to output to each switching element of the inverter circuit.

  The determination of the reference position of the mechanical angle of the motor may be performed only once when the PWM waveform signal for the intermittent energization drive method is output to each switching element of the inverter circuit at the time of starting the motor. desirable.

  The torque fluctuation correction value may be set based on a fluctuation pattern of the load torque of the motor measured in advance.

  The compressor driving device according to the present invention includes the motor control device having any one of the above-described configurations.

  According to the motor control device of the present invention, it is possible to control a motor connected to a load with a large variation in load torque without using a sensor for detecting the rotor position with high efficiency, and to reduce the amount of calculation in the control. Can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings. An example of the configuration of a motor control device according to the present invention is shown in FIG. A motor control device according to the present invention shown in FIG. 1 includes a converter circuit 2, an inverter circuit 3, a three-phase brushless motor 4 (hereinafter referred to as “motor 4”), a current detection resistor 5, and a DC current detection amplifier 6. And the microcomputer 7, and receives power from the commercial power source 1.

  The converter circuit 2 converts the AC voltage from the commercial power source 1 into a DC voltage and supplies it to the inverter circuit 3. A three-phase AC voltage output from the inverter circuit 3 is supplied to the motor 4. The converter circuit 2 and the inverter circuit 3 are connected by a positive DC line and a negative DC line, and a current detection resistor 5 is provided on the negative DC line. The DC current detection amplifier 6 detects a DC current flowing from the converter circuit 2 to the inverter circuit 3 based on the voltage generated at both ends of the current detection resistor 5, amplifies the detected DC current, and outputs a micro current as a DC current signal. The data is output to the phase difference detection unit 8 in the computer 7.

  The microcomputer 7 is a circuit for driving and controlling the motor 4, and includes a phase difference detection unit 8, a target phase difference information storage unit 9, an adder 10, a PI calculation unit 11, and a rotation speed setting unit 12. , Sine wave data table 13, sine wave data creation unit 14, PWM data creation unit 15, torque fluctuation correction value table 16, motor rotor mechanical angle setting unit 17, torque correction data creation unit 18, torque A variation correction value adder 19, a PWM creation unit 20, an intermittent energization drive unit 21, and a drive method selection unit 22 are included, and each process is performed in software according to a program.

  The phase difference detection unit 8 uses the DC current signal that is the output of the DC current detection amplifier 6 and the U-phase motor drive voltage phase information output from the electric sine wave data creation unit 14 to use the motor drive voltage and the motor. A phase difference from the winding current is detected, and information on the detected phase difference (hereinafter referred to as phase difference information) is output to the adder 10. Details of the detection method in the phase difference detection unit 8 will be described later.

  The target phase difference information storage unit 9 stores information on the phase difference between the target motor drive voltage and the motor winding current (hereinafter referred to as target phase difference information), and the target phase difference information is stored in the adder 10. Output.

  The adder 10 subtracts the phase difference value of the phase difference information output from the phase difference detection unit 8 from the target phase difference value of the target phase difference information output from the target phase difference information storage unit 9 to obtain the target position. An error amount between the phase difference and the detected phase difference is obtained, and the error amount is output to the PI calculation unit 11.

  The PI calculation unit 11 performs a predetermined amplification on the error amount by P control to calculate a proportional error amount, integrates the error amount by I control, amplifies the integrated value, and calculates an integration error amount Then, the proportional error amount and the integral error amount are added to obtain a duty reference value, and the duty reference value is output to the PWM data creating unit 15.

  The motor control apparatus according to the present invention shown in FIG. 1 does not employ a method for detecting a counter electromotive voltage pulse or the like to perform speed control, and the motor drive voltage at which the motor 4 is energized in the motor windings. A so-called forced excitation drive system determined by frequency is adopted. Hereinafter, the setting of the rotation speed and the PWM output will be described.

  The rotation speed setting unit 12 sets a rotation speed command for the motor 4 when the drive method selection unit 22 selects the 180-degree energization drive method. The sine wave data table 13 stores in advance a data string (sine wave data composed of a predetermined number of data) in which a sine wave waveform is output when analog values are continuously output, and a reference address of this data string Is updated by a predetermined number for each PWM carrier period. The larger the predetermined number, the higher the motor 4 rotates. That is, the rotational speed of the motor 4 is determined by the PWM carrier frequency and the reference address update interval (predetermined number) stored in the sine wave data table 13 in advance, excluding the structure of the motor 4. It is determined. Incidentally, the reference address is the phase information itself of the motor drive voltage. Note that the sine wave data may be created by performing a sine wave calculation each time without creating based on the sine wave data table.

  The sine wave data creation unit 14 shifts sine wave data corresponding to each phase of the motor winding terminal of the motor 4 (shifted by 120 degrees in electrical angle) based on the rotation speed command set by the rotation speed setting unit 12. Sine wave data) is read from the sine wave data table 13 and output to the PWM data creating unit 15, and the U-phase motor drive voltage phase information is obtained from the U-phase sine wave data by the phase difference detection unit 8 and the motor rotor machine. Output to the angle setting unit 17.

  The PWM data creation unit 15 multiplies the sine wave data of each phase obtained by the sine wave data creation unit 14 by the duty reference value obtained by the PI calculation unit 11, and outputs PWM data based on the multiplication value. . For example, the PWM data generation unit 15 generates a triangular wave at a PWM carrier cycle, compares the peak value of the triangular wave with the multiplication value, and outputs High / Low based on the comparison result, thereby generating PWM for each phase. Output data.

  The torque fluctuation correction value table 16 stores in advance torque fluctuation correction values composed of a predetermined number of data. The motor rotor mechanical angle setting unit 17 sets the motor rotor mechanical angle of the motor 4 based on the U-phase motor drive voltage phase information output from the sine wave data creation unit 14. The torque correction data creation unit 18 reads the torque variation correction value from the torque variation correction value table 18 based on the motor rotor mechanical angle of the motor 4 set by the motor rotor mechanical angle setting unit 17, and generates torque variation. Output to the correction value adder 19.

  The torque fluctuation correction value adder 19 adds the PWM data of each phase output from the PWM data creation unit 15 and the torque fluctuation correction value output from the torque correction data creation unit 18, and creates a PWM calculation result. To the unit 20. The PWM creation unit 20 creates a PWM waveform signal to be output to each switching element of the inverter circuit 3 based on the output of the torque fluctuation correction value adder 19 and outputs the PWM waveform signal to each switching element of the inverter circuit 3.

  According to the above configuration, the magnitude of the motor drive voltage (duty width of the PWM duty) is determined by the phase difference control feedback loop for controlling the phase difference between the motor drive voltage and the motor winding current to be constant. Further, in order to rotate the motor 4 at a desired rotational speed, the rotational speed is determined by sine wave data output at a desired frequency. As a result, the motor 4 is driven and controlled with a desired phase difference and a desired rotational speed.

  FIG. 2 shows the relationship between the state of each switching element of the inverter circuit 3 and the direct current Idc flowing from the converter circuit 2 to the inverter circuit 3. The value of the DC current Idc during the first energization period T1 in which only the U-phase upper arm switching element is energized among the upper arm switching elements of the inverter circuit 3 is substantially Idc1, and the U-phase of the lower arm switching elements of the inverter circuit 3 The value of the direct current Idc in the second energization period T2 in which only the lower arm switching element is energized is substantially Idc2.

  FIG. 3 is a diagram showing the relationship between the DC current Idc and the motor winding current in the first energization period T1 of FIG. 3 that are the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted. The inverter circuit 3 is composed of three pairs of switching elements (for example, transistors), which are simplified in FIG. 3 and include a U-phase upper arm switching element, a V-phase upper arm switching element, a W-phase upper arm switching element, and a U-phase lower arm switching element. , The V-phase lower arm switching element and the W-phase lower arm switching element are shown as switches SW1 to SW6, respectively. In the first energization period T1 of FIG. 2, only the switch SW1 is energized among the upper arm switching elements of the inverter circuit 3. Therefore, the value of the direct current Idc is approximately Idc1, which is equal to the U-phase current (Iu).

  FIG. 4 is a diagram showing the relationship between the DC current Idc and the motor winding current in the second energization period T2 of FIG. 4 that are the same as those in FIGS. 1 and 3 are given the same reference numerals, and descriptions thereof are omitted. In the second energization period T2 of FIG. 2, only the switch SW6 is energized among the lower arm switching elements of the inverter circuit 3. Therefore, the value of the direct current Idc is Idc2, which is equal to the −W phase current (−iw).

  Considering similarly, AC currents Iu, Iv, and Iw of each phase appear in the DC current Idc in accordance with the U, V, and W phase PWM pulse patterns, and the relationship is as shown in FIG.

  Further, the relationship among the alternating currents Iu, Iv, Iw of each phase appearing in the direct current Idc according to the alternating voltage data is as shown in FIG. Thus, in the current detection modes 1 and 2, that is, in the range where the electric conduction angle of the motor 4 is 30 ° to 150 °, the direct current Idc when only one of the upper arm switching elements is energized is If detected, the U-phase current (Iu) can be detected.

  Next, a method for obtaining phase difference information (information on the phase difference between the motor drive voltage and the motor winding current) using the detected U-phase current (Iu) will be described. As shown in FIG. 7, phase difference information is calculated from the area ratio of the detected U-phase current (Iu). That is, as shown in FIG. 8, the first phase period θ0 in the U-phase voltage phase is 30 to 90 degrees, and the second phase period θ1 is 90 to 150 degrees. Each sampling timing is set to be sampled n times (three times in the case of FIG. 8, total 6 times) at equal phase intervals of ts. Then, the U-phase current signal area S0 in the first phase period θ0 is obtained by integrating the current values I0, I1, and I2 (S0 = I0 + I1 + I2), and the U-phase current signal area S1 in the second phase period θ1 is calculated. The current values I3, I4, and I5 are integrated (S1 = I3 + I4 + I5), and the ratio of the two U-phase current signal areas (S0 / S1) is calculated as phase difference information. In the case of FIG. 8, the phase difference information is 1.

  In the current detection modes 4 and 5, that is, when the electric conduction angle of the motor 4 is in the range of 210 ° to 330 °, the DC current Idc when only one of the lower arm switching elements is energized is detected. Then, it is possible to detect the -U phase current (-Iu). Using this -U phase current (-Iu), as shown in FIG. 9, phase difference information may be calculated from the area ratio (S2 / S3) of the detected -U phase current (-Iu).

  Furthermore, the phase difference information calculated by the method shown in FIG. 7 and the phase difference information calculated by the method shown in FIG. 9 may be averaged.

  Here, a case where a load having a large load fluctuation during motor rotation as shown in the load torque characteristic of the reciprocating compressor shown in FIG. In phase difference control in which the phase difference between the motor drive voltage and the motor winding current is controlled to be constant, it is difficult to follow such large and rapid load torque fluctuations due to the phase difference detection period and the like. For this reason, in the motor control device using the inverter device proposed in Patent Document 1, when the load torque is large, the phase difference between the motor drive voltage and the motor winding current deviates from the motor driveable range. It will cause step-out. On the other hand, when the load torque is small and the motor drive voltage is excessive, the motor torque generated excessively becomes vibrational and eventually causes the motor to step out.

  Therefore, in the motor control apparatus according to the present invention shown in FIG. 1, the torque fluctuation correction value table 16 stores in advance a torque fluctuation correction value composed of a predetermined number of data, and the torque correction data creation unit 18 performs motor rotation. A torque fluctuation correction value is read from the torque fluctuation correction value table 18 based on the motor rotor mechanical angle of the motor 4 set by the child machine angle setting section 17, and the torque fluctuation correction value adder 19 is used as a PWM data creation section. The PWM data of each phase output from 15 and the torque fluctuation correction value output from the torque correction data creation unit 18 are added, and the calculation result is output to the PWM creation unit 20. The PWM creation unit 20 A PWM waveform signal to be output to each switching element of the circuit 3 is created based on the output of the torque fluctuation correction value adder 19, and Is output to the switching element. As a result, the motor torque of the motor 4 is increased or decreased according to the torque fluctuation correction value, and torque control according to the load torque is performed, so that motor step-out is prevented, and further, fluctuations in the rotational speed during one rotation of the motor 4 occur. It can be suppressed. Therefore, it is possible to control a motor connected to a load having a large variation in load torque with high efficiency. Furthermore, the amount of calculation in the control can be reduced as compared with the motor control device proposed in Patent Document 2.

  Here, the torque fluctuation correction value is a torque correction amount A0 for each mechanical angle corresponding to the mechanical position of the motor rotor, as shown in FIG. Further, the load torque characteristic A1 of the reciprocating compressor is measured in advance, and the torque fluctuation correction value is set so that the motor torque characteristic and the load torque characteristic A1 of the reciprocating compressor are substantially equal.

  Here, each data of the torque fluctuation correction value table 16 and each data of the sine wave data table 13 are divided by the same phase of the mechanical angle corresponding to the mechanical position of the motor rotor. Further, as apparent from FIG. 11, the torque fluctuation correction value is uniquely determined by the mechanical angle corresponding to the mechanical position of the motor rotor. However, the inverter driving voltage phase for each mechanical angle is determined during driving by the intermittent energization driving method after starting, and in the case of a three-phase four-pole brushless motor as an example, the mechanical angle in the case of a three-phase four-pole motor The electrical angle is 1-360 ° with respect to 1-180 °, the electrical angle is 1-360 ° with respect to the mechanical angle of 181 ° -360 °, and the phase difference of the electrical angle is not uniquely determined. It is necessary to judge.

  An example of the mechanical angle determination process will be described with reference to the flowchart of FIG.

  During the operation of the flowchart of FIG. 12, the drive method selection unit 22 selects the intermittent energization drive method and drives the motor 4 by the intermittent energization drive method. The intermittent energization drive unit 21 first measures the time period P1 (step S21), and then measures the time period 2 (step S22). Thereafter, the intermittent energization drive unit 21 determines whether or not the period P1 is longer than the period P2 (step S23).

  If the period P1 is longer than the period P2 (YES in step S23), the intermittent energization drive unit 21 increments the count T1 of the built-in period P1 counter, and counts T2 of the built-in period P2 counter. Is set to 0 (step S24), and then the process proceeds to step S26. The reason why the count T2 of the counter for period P2 is set to 0 is that the time of each period may change depending on the load state. However, in order to prevent the determination of the mechanical angle when the motor 4 drives a compressor having a small load fluctuation at one rotation of the mechanical angle of the rotor, the count number T2 of the counter for the period P2 is set to 0. Instead, the count number T2 of the counter for the period P2 may be decremented.

  If the period P1 is not longer than the period P2 (NO in step S23), the intermittent energization drive unit 21 increments the count number T2 of the period P2 counter, and sets the count number T1 of the period P1 counter to 0. (Step S25), and then the process proceeds to Step S27. The reason why the count T1 of the counter for the period P1 is set to 0 is that the time of each period may vary depending on the load state. However, in order to prevent the determination of the mechanical angle when the motor 4 drives a compressor having a small load fluctuation in one rotation of the mechanical angle of the rotor, the count number T1 of the counter for the period P1 is set to 0. Instead, the count number T1 of the counter for the period P1 may be decremented.

  In step S26, the intermittent energization drive unit 21 determines whether or not the count number T1 of the period P1 counter is greater than a predetermined number N. If the count number T1 of the period P1 counter is not greater than the predetermined number N (NO in step S26), the process proceeds to step S21. On the other hand, if the count number T1 of the counter for the period P1 is larger than the predetermined number N (YES in step S26), the mechanical angle can be determined, and the process proceeds to step S28.

  In step S27, the intermittent energization drive unit 21 determines whether or not the count number T2 of the cycle P2 counter is greater than a predetermined number N. If the count number T2 of the counter for the period P2 is not greater than the predetermined number N (NO in step S27), the process proceeds to step S21. On the other hand, if the count number T2 of the counter for period P2 is larger than the predetermined number N (YES in step S27), the mechanical angle can be determined, and the process proceeds to step S28.

  In step S28, the intermittent energization drive unit 21 determines a mechanical angle of 0 degree. For example, the switching point from the cycle P1 to the cycle P2 is set to 0 degree mechanical angle. If the mechanical angle of 1 ° -180 ° is set as state 1 and the mechanical angle of 181 ° -360 ° is set as state 2 after the mechanical angle of 0 ° is determined, the mechanical angle can be determined from the state and electrical angle information. it can.

  The flowchart of FIG. 12 relates to the case where there are two types of cycles, but if the cycle is three or more types, the count number of the counter dedicated to the longest cycle may be incremented.

  The data stored in advance in the torque fluctuation correction value table 16 is a correction amount of the PWM duty when the motor torque is controlled by the PWM duty. Here, since the load fluctuation of the compressor depends on the pressure of the compressor cycle and does not depend on the number of rotations of the motor driving the compressor, the torque fluctuation correction pattern stores only one torque fluctuation correction pattern. Keep it.

  Here, during a period when the pressure of the cycle is not stable, such as after starting, the driving method selection unit 22 selects the intermittent energization driving method, and the intermittent energization driving unit 21 generates the PWM without performing correction using the torque fluctuation correction value. The PWM data of each phase is supplied to the unit 20 to drive the motor 4 by the intermittent energization drive method, and the drive method selection unit 22 switches the selection from the intermittent energization drive method to the 180-degree energization drive during the drive, and the drive method selection unit According to the selection of 22, the driving method is switched from the intermittent energization driving method to the 180-degree energization driving method, so that the torque fluctuation correction value to be stored can be made one. If there is a means for determining the compressor cycle pressure, a plurality of torque correction patterns are stored, and the control performance can be further improved by selecting the torque correction pattern according to the compressor cycle pressure. Can be improved. In addition, the drive waveform in the rectangular wave 120 degree | times drive method which is an example of an intermittent drive method is as shown in FIG. FIG. 13 is a waveform diagram showing the PWM waveform signal for driving the switching element of the inverter circuit 13 as an analog value for each coil terminal. The drive waveform during the actual energization period is PWM chopped at several to several tens of kHz. Yes.

  Next, the relationship between load torque, motor drive voltage (for one phase), and angular velocity when a single rotary compressor motor having a large load fluctuation during one rotation is driven will be shown. FIG. 14 shows the case of the motor control device using the inverter device proposed in Patent Document 1, and FIG. 15 shows the case of the motor control device according to the present invention shown in FIG. In the motor control device using the inverter device proposed in Patent Document 1, the fluctuation of the angular velocity is large, and the vibration of the compressor is also large, but the motor control device according to the present invention shown in FIG. The duty reference value is corrected by the value, and the motor drive voltage is corrected, so that the motor winding current is corrected so that the motor torque and the load torque coincide with each other, the angular speed fluctuation is reduced, and the compressor vibration is also reduced. Become.

These are figures which show the example of 1 structure of the motor control apparatus which concerns on this invention. These are figures which show the relationship between the state of each switching element of an inverter circuit, and the direct current which flows into a inverter circuit from a converter circuit. These are figures which show the relationship between the direct current and motor winding current in the 1st electricity supply period. These are figures which show the relationship between the direct current and motor winding current in the 2nd electricity supply period. These are figures which show the alternating currents Iu, Iv, and Iw of each phase which appear in a direct current according to the PWM pulse pattern of U, V, and W phases. These are figures which show the alternating currents Iu, Iv, and Iw of each phase which appear in a direct current according to alternating voltage data. These are the figures for demonstrating the area ratio of the U-phase electric current used for the calculation of the phase difference information in a 1st electricity supply period. These are figures which show the relationship between the U-phase voltage phase information and the sampling timing of a U-phase current. These are the figures for demonstrating the area ratio of -U phase current used for the calculation of the phase difference information in a 2nd electricity supply period. These are figures which show the load torque fluctuation | variation of a reciprocating compressor. These are the figures which show the relationship between the mechanical angle of each state in the case of a 3 phase 4 pole brushless motor in the motor control apparatus shown in FIG. 1, and an electrical angle. These are flowcharts of the mechanical angle determination process. These are figures which show the drive waveform in a rectangular wave 120 degree | times energization drive system. These are the figures which show the relationship between the load torque, the motor drive voltage, and angular velocity in the conventional motor control apparatus. These are figures which show the relationship between the load torque, the motor drive voltage, and angular velocity in the motor control apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Converter circuit 3 Inverter circuit 4 3 phase brushless motor 5 Current detection resistance 6 DC current detection amplifier 7 Microcomputer 8 Phase difference detection part 9 Target phase difference information storage part 10 Adder 11 PI calculation part 12 Rotation speed setting part DESCRIPTION OF SYMBOLS 13 Sine wave data table 14 Sine wave data creation part 15 PWM data creation part 16 Torque fluctuation correction value table 17 Motor rotor mechanical angle setting part 18 Torque correction data creation part 19 Torque fluctuation correction value adder 20 PWM creation part 21 Intermittent conduction Drive unit 22 Drive system selection unit

Claims (6)

A motor driving inverter circuit for converting DC power to AC power, and a control device for controlling the inverter circuit by a phase difference control method;
The controller is
A phase difference detecting means for detecting a phase difference between the motor driving voltage and the motor winding current based on a direct current flowing through the inverter circuit;
PWM data creation means for creating PWM data for the 180-degree energization drive method according to the phase difference;
Storage means for storing in advance a torque fluctuation correction value corresponding to the mechanical angle of the motor;
A motor having PWM waveform signal generating means for generating a PWM waveform signal to be output to each switching element of the inverter circuit from the PWM data for the 180-degree conduction drive method and the torque fluctuation correction value. Control device.   2. The motor control device according to claim 1, wherein the PWM waveform signal generating unit generates the PWM waveform signal based on an added value of the PWM data for the 180-degree conduction drive method and the torque fluctuation correction value.   The control device has means for creating a PWM waveform signal for intermittent energization drive method, and the PWM circuit signal for intermittent energization drive method is not used at the start of the motor, and the PWM waveform signal for intermittent energization drive method is used as the inverter circuit. The motor control device according to claim 1, wherein the motor control device outputs to each of the switching elements.   The reference position of the mechanical angle of the motor is determined only once when the PWM waveform signal for the intermittent energization drive method is output to each switching element of the inverter circuit at the time of starting the motor. 4. The motor control device according to any one of 3.   The motor control device according to claim 1, wherein the torque fluctuation correction value is set based on a fluctuation pattern of a load torque of the motor measured in advance.   A compressor driving device comprising the motor control device according to claim 1.