JP5309926B2 - Compressor control device - Google Patents

Description

  The present invention relates to an inverter circuit that drives a motor by a switching element that is PWM controlled, and more particularly to a control device that is suitable for driving a compressor mounted in a refrigerator.

  Conventionally, in this type of compressor control device, there is one that detects the motor rotation speed and varies the duty ratio of the PWM signal to control the rotation speed of the motor (see, for example, Patent Document 1).

  Patent Document 1 is to prevent the compressor from resonating due to the operation of a DC motor incorporated in the compressor.

  The conventional compressor control apparatus will be described below with reference to the drawings.

  FIG. 3 is a circuit diagram of a conventional compressor control device described in Patent Document 1, and FIG. 4 is a flowchart of the conventional compressor control device, illustrating an operation for raising and lowering the rotational speed of the DC motor. Is.

  In FIG. 3, an AC / DC converter 1 is connected to a commercial power source 2 and converts a commercial AC voltage into a DC voltage. The inverter circuit 3 is connected to the AC / DC converting means 1 and the output is connected to the DC motor 4.

  The DC motor 4 is incorporated in a compressor 15 that cools a refrigerator or the like.

  The inverter circuit 3 includes six switching elements T1, T2, T3, T4, T5, and T6, and the six switching elements are connected in a three-phase bridge.

  The control circuit 5 includes position detection means 6, commutation means 7, rotation speed control means 8, rotation speed calculation means 9, command rotation speed detection means 10, rotation speed comparison means 11, synthesis means 12, and drive means 13. ing.

  The position detection means 6 detects the position of the rotor from the back electromotive voltage of the DC motor 4 and sends a position detection signal to the commutation means 7, the rotation speed control means 8, and the rotation speed calculation means 9.

  The commutation means 7 sends commutation pulses driven by the synthesis means 12 in accordance with the output of the position detection means 6.

  The rotation speed calculation means 9 calculates the rotation speed of the DC motor 4 by counting the position detection signal of the position detection means 6 for a certain period or measuring the pulse interval, and the rotation speed comparison means 11 operates the DC motor 4. The number of rotations being sent is sent out.

  On the other hand, the command rotational speed detection means 10 detects the command rotational speed sent from the refrigerator or the like and sends it to the rotational speed comparison means 11.

  The rotation speed comparison means 11 compares the rotation speed of the DC motor 4 from the rotation speed calculation means 9 with the command rotation speed from the command rotation speed detection means 10, and if the rotation speed of the DC motor 4 is smaller than the command rotation speed, the duty is The output for increasing the ratio is output to the rotation speed control means 8, and the rotation speed control means 8 increases the duty ratio and increases the voltage applied to the DC motor 4 to increase the rotation speed.

  When the rotational speed of the DC motor 4 is larger than the command rotational speed, an output for decreasing the duty ratio is output to the rotational speed control means 8, and the rotational speed control means 8 applies the duty ratio to the DC motor 4 with the ratio reduced. The rotational speed is decreased by decreasing the voltage.

  Further, the rotational speed control means 8 outputs the current duty ratio to the rotational speed comparison means 11.

  If the duty ratio output from the rotational speed control means 8 is 100%, the rotational speed comparison means 11 will rotate the rotational speed calculation means 9 when the rotational speed calculated by the rotational speed calculation means 9 is lower than the command rotational speed. The number of revolutions that is lower than the number of revolutions calculated in (1) and is closest to the number of revolutions is selected from the set number of revolutions storage means 14, and the selected number of revolutions is compared with the number of revolutions calculated by the revolution number calculation means 9.

  The rotational speed setting rotational speed storage means 14 stores a plurality of rotational speeds that avoid the resonant rotational speed of the compressor 15.

  Further, when the rotation speed is selected from the set rotation speed storage means 14, the rotation speed comparison means 11 determines that the command rotation speed and the rotation speed are the duty ratio output from the rotation speed control means 8 is 90% or less. The rotation speed calculated by the calculation means 9 is compared.

  The synthesizing unit 12 outputs the logical product of the outputs of the commutation unit 7 and the rotation speed control unit 8 to the drive unit 13, and the drive unit 13 drives the switching elements T <b> 1 to T <b> 6 constituting the inverter circuit 3.

  With respect to the control device for the compressor 15 configured as described above, the operation of raising and lowering the rotational speed of the DC motor 4 will be described below with reference to FIG.

  When the control device of the compressor 15 receives the change of the command rotational speed from the control device such as the refrigerator by the command rotational speed detection means 10 while the DC motor 4 is in operation, it controls the rotational speed of the DC motor 4 to be changed.

  In STEP1, the command rotational speed is stored as a reference rotational speed.

  In STEP 2, the rotation speed calculation means 9 calculates the rotation speed of the DC motor 4 from the signal of the position detection means 6. In STEP 3, the rotation speed comparison means 11 detects the command rotation speed and rotation speed calculation means detected by the command rotation speed detection means 10. The rotational speed calculation result of the DC motor 4 calculated in 9 is compared.

  When the rotational speed calculation result is smaller than the command rotational speed at STEP 4, the routine proceeds to STEP 5, and at STEP 5, the rotational speed comparison means 11 determines whether the duty ratio output from the rotational speed control means 8 is 100%. If the duty ratio is not 100%, the process proceeds to STEP6. In STEP6, the rotational speed control means 8 increases the duty ratio and proceeds to STEP10. As a result, the ON time increases, so that the voltage applied to the DC motor 4 increases and the rotational speed of the DC motor 4 increases.

  If the duty ratio is 100% in STEP5, proceed to STEP7. In STEP7, set the rotational speed closest to the rotational speed lower than the commanded rotational speed and lower than the rotational speed calculated by the rotational speed calculating means 9 in STEP7. Selection is made from the rotation speed storage means 14, and the process proceeds to STEP 10.

  If the rotational speed calculation result is not smaller than the reference rotational speed in STEP4, the process proceeds to STEP8.

  When the rotational speed calculation result is larger than the reference rotational speed in STEP 8, the process proceeds to STEP 9, and the rotational speed control means 8 decreases the duty ratio. As a result, the ON time decreases, so the voltage applied to the DC motor 4 decreases and the rotational speed of the DC motor 4 decreases.

  If the rotational speed calculation result is not greater than the reference rotational speed in STEP 8, the process proceeds to STEP 10.

  In STEP 10, if the reference rotation speed is equal to or greater than the command rotation speed, the process returns to STEP 1 and the command rotation speed is stored again as the reference rotation speed. If not, the process proceeds to STEP11, where it is determined whether the duty ratio output from the rotation speed control means 8 is 90% or less at STEP11, and the duty ratio output from the rotation speed control means 8 is 90% or less at STEP11. If not, return to STEP2.

  If the duty ratio output from the rotational speed control means 8 in STEP 11 is 90% or less, the process returns to STEP 1 and the command rotational speed is stored again as the reference rotational speed.

  Therefore, when a command rotational speed greater than the current rotational speed is input and the duty ratio does not reach 100%, STEP1, STEP2, STEP3, STEP4, STEP5, STEP6 and STEP10, the rotational speed control means 8 gradually increases the duty ratio. When the rotational speed of the DC motor 4 is increased and the reference rotational speed and the rotational speed calculation result are the same, the process proceeds to STEP1, STEP2, STEP3, STEP8, and STEP10. And the rotational speed of the DC motor 4 is maintained at the reference rotational speed.

  When the duty ratio reaches 100%, the process proceeds to STEP1, STEP2, STEP3, STEP4, STEP5, STEP7, and STEP10, and the reference rotational speed is lower than the rotational speed calculated by the rotational speed calculation means 9 and is closest to the rotational speed. Return to STEP2 as the selected number of rotations, proceed to STEP3, and in STEP4, the reference rotation number is lower than the rotation number calculated by the rotation number calculation means 9, so proceed to STEP8, proceed to STEP8, STEP9, and decrease the duty ratio Then, the rotation speed control means 8 decreases the rotation speed of the DC motor 4 by gradually decreasing the duty ratio.

If the reference rotation speed and the rotation speed calculation result are the same, the process proceeds to STEP2, STEP3, STEP8, and STEP10, and the rotation speed control means 8 does not change the duty ratio and maintains the rotation speed of the DC motor 4 at the reference rotation speed. .
JP-A 62-66080

  However, in the above conventional configuration, when the load such as the refrigerator is in an overload state or the input voltage is lowered, if the maximum rotation speed is input as the command rotation speed, the rotation speed control means 8 is duty cycle. Although the ratio is increased, the duty ratio is 100%, that is, the operation is performed at a rotation speed that avoids resonance when all the times are turned on.

  At this time, depending on the load condition, the duty ratio may drop when operating at a speed that avoids resonance, and may immediately start again at the command speed. Thus, the fluctuating sound of the compressor 15 due to the operating rotational speed is generated.

  The present invention solves the above-described conventional problems, and when changing the operating speed to a speed that avoids resonance, the fluctuation noise of the compressor is eliminated by operating at that speed for a certain period of time. With the goal.

  In order to solve the above-described conventional problems, the compressor control device of the present invention calculates the rotation speed by the rotation speed calculation means, compares the rotation speed of the command rotation speed with the calculated motor rotation speed, and rotates the rotation speed. When the output from the rotation speed control means is 100% duty ratio, the rotation speed lower than the command rotation speed is stored in the set rotation speed storage means. The selected number of rotations is selected, the selected number of rotations is compared with the number of rotations calculated by the number-of-rotations calculation means, and control is performed to operate at the selected number of rotations for a certain period of time. Disappears.

  The compressor control apparatus according to the present invention does not operate at a rotational speed at which the compressor fluctuates, and can eliminate the fluctuating noise of the compressor.

The present invention controls a voltage applied to a motor by adjusting a duty ratio that is a ratio of an on-time within a carrier cycle, and a control device for a compressor that controls the motor at a variable speed. In this case, the number of revolutions avoiding the resonance of the compressor is selected and the operation is performed for a certain time, and the compressor is not operated at the fluctuating number of revolutions.

Further, the present invention is based on an inverter circuit in which a plurality of semiconductor switches are bridge-connected, a position detecting means for detecting a position of a rotor of a motor and generating a position detection signal, and an output of the position detecting means. Commutation means for determining the operation of the inverter circuit and outputting commutation pulses, and controlling the voltage by adjusting the duty ratio, which is the ratio of the on-time, within the carrier period in order to make the rotation speed of the compressor variable Rotation speed control means, drive means for operating the inverter circuit by the output of the commutation means and the output of the rotation speed control means, and rotation speed calculation means for calculating the rotation speed of the motor from the output of the position detection means And a set rotational speed storage means for storing the rotational speed at which the motor can be operated, the rotational speed of the command rotational speed and the motor speed calculated by the rotational speed calculation means. The rotational speed of the motor is output to the rotational speed control means so that the rotational speed of the motor becomes the command rotational speed, and the duty ratio output from the rotational speed control means becomes 100%. In a compressor control device having a timer that operates, if the duty ratio output from the rotational speed control means reaches 100%, a setting lower than the command rotational speed is stored in the set rotational speed storage means After selecting the number of revolutions, operating the compressor, and after the timer reaches a set value, if the duty ratio output from the revolution number control means becomes a certain value or less, the command revolution number and the revolution number calculation means The rotation speed comparison means for comparing the calculated rotation speeds is provided, and the compressor is not operated at a fluctuating rotation speed.

In the present invention, when the duty ratio output from the rotation speed control means reaches 100%, the rotation speed is lower than the command rotation speed and is equal to or less than the rotation speed calculated by the rotation speed calculation means. Therefore, in addition to the effect of the invention described in claim 1, it is further possible to minimize a decrease in cooling performance of the refrigerator and the like, and to minimize the number of rotations at which the compressor fluctuates.

Moreover, since this invention controls a refrigerator and can reduce the fluctuation | variation sound of a compressor, it can provide a refrigerator with few fluctuation | variation noises.

(Embodiment 1)
FIG. 1 is a circuit diagram of a compressor control apparatus according to the first embodiment of the present invention, and FIG. 2 is a flowchart of the compressor control apparatus according to the first embodiment, which prevents a change in the rotational speed of the DC motor. The operation will be described.

  In FIG. 1, six switching elements T101, T102, T103, T104, and T105 that constitute an AC / DC conversion means 101, a commercial power source 102, an inverter circuit 103, a DC motor 104 that is a motor, a compressor 115, and an inverter circuit 103. , T106 are the same as those in the conventional example, and thus detailed description thereof is omitted.

  The control circuit 105 includes a position detection unit 106 that detects the position of the rotor 104a, a commutation unit 107, a rotation number control unit 108, a rotation number calculation unit 109, a command rotation number detection unit 110, a rotation number comparison unit 111, and a timer 117. , The combining means 112 and the drive means 113.

  Position detection means 106, commutation means 107, position detection signal commutation means 107, rotation speed control means 108, rotation speed calculation means 109, rotation speed calculation means 109, command rotation speed detection means 110, synthesis means 112, drive means 113 and the set rotational speed storage means 114 are the same as those in the conventional example, and thus detailed description thereof is omitted.

  The rotation speed comparison means 111 compares the rotation speed of the DC motor 104 from the rotation speed calculation means 109 with the command rotation speed from the command rotation speed detection means 110, and if the rotation speed of the DC motor 104 is smaller than the command rotation speed, the duty is compared. An output for increasing the ratio is output to the rotation speed control means 108, and the rotation speed control means 108 increases the rotation speed by increasing the duty ratio and increasing the voltage applied to the DC motor 104.

  When the rotational speed of the DC motor 104 is larger than the command rotational speed, an output for decreasing the duty ratio is output to the rotational speed control means 108, and the rotational speed control means 108 decreases the duty ratio and outputs a voltage applied to the DC motor 104. Decrease the rotation speed by decreasing.

  The rotation speed control means 108 outputs the current duty ratio to the rotation speed comparison means 111 and the timer 117.

  If the duty ratio output from the rotation speed control means 108 is 100%, the rotation speed comparison means 111 is the rotation speed calculation means 109 when the rotation speed calculated by the rotation speed calculation means 109 is lower than the command rotation speed. The number of revolutions lower than the number of revolutions calculated in (1) and closest to the number of revolutions is selected from the set revolution number storage means 114, and the selected number of revolutions is compared with the number of revolutions computed by the revolution number computation means 109.

  The timer 117 starts operating for a fixed time if the duty ratio output from the rotational speed control means 108 is 100%, and outputs it to the rotational speed comparison means 111 while the timer 117 is operating.

  The rotation speed comparison means 111 does not detect the duty ratio output from the rotation speed control means 108 while the timer 117 is operating.

  When the operation of the timer 117 is completed and there is no output, the duty ratio output from the rotational speed control means 108 is read, and the duty ratio output from the rotational speed control means 108 is 90% or less. For example, the command rotational speed and the rotational speed calculated by the rotational speed calculating means 109 are compared.

  The operation of raising and lowering the rotational speed of the DC motor 104 will be described below with reference to FIG.

  When the control device of the compressor 115 receives the change of the command rotational speed from the control device such as the refrigerator by the command rotational speed detection means 110 while the DC motor 104 is in operation, it controls the rotational speed of the DC motor 104 to be changed.

  In STEP 101, the command rotational speed is stored as a reference rotational speed.

  In STEP 102, the rotational speed calculation means 109 calculates the rotational speed of the DC motor 104 from the signal of the position detection means 106. In STEP 103, the rotational speed comparison means 111 detects the command rotational speed and rotational speed calculation means detected by the command rotational speed detection means 110. The rotational speed calculation result of the DC motor 104 calculated in 109 is compared.

  When the rotational speed calculation result is smaller than the command rotational speed in STEP 104, the process proceeds to STEP 105. In STEP 105, the rotational speed comparison means 111 determines whether the duty ratio output from the rotational speed control means 108 is 100%. If the duty ratio is not 100%, the process proceeds to STEP 106. In STEP 106, the duty ratio of the rotation speed control means 108 is increased, and the process proceeds to STEP 110. As a result, the ON time increases, so that the voltage applied to the DC motor 104 increases and the rotational speed of the DC motor 104 increases.

  If the duty ratio is 100% in STEP 105, the process proceeds to STEP 107. In STEP 107, the reference rotational speed is lower than the command rotational speed, lower than the rotational speed calculated by the rotational speed calculation means 109, and closest to the rotational speed. Is selected from the set rotational speed storage means 114 and set.

  Then, the process proceeds to STEP 110 and proceeds to STEP 120 and STEP 110 for turning on the timer 117.

  In STEP 104, if the rotational speed calculation result is not smaller than the reference rotational speed, the process proceeds to STEP 108.

  In STEP 108, if the rotational speed calculation result is larger than the reference rotational speed, the routine proceeds to STEP 109, where the rotational speed control means 108 decreases the duty ratio. As a result, the ON time decreases, so that the voltage applied to the DC motor 104 decreases and the rotational speed of the DC motor 104 decreases.

  In STEP 108, if the rotation speed calculation result is not larger than the reference rotation speed, the process proceeds to STEP 110.

  In STEP 110, if the reference rotation speed is equal to or greater than the command rotation speed, the process returns to STEP 101, and the command rotation speed is stored again as the reference rotation speed. Otherwise, the process proceeds to STEP 130, and if the timer 117 is in operation, the process returns to STEP 102. If the operation is completed, the process proceeds to STEP 111. In STEP 11, it is determined whether the duty ratio output from the rotation speed control means 108 is 90% or less. If the duty ratio output from the rotation speed control means 108 is not 90% or less in STEP 111, the process returns to STEP 102.

  In STEP 111, if the duty ratio output from the rotational speed control means 108 is 90% or less, the process returns to STEP 101, and the command rotational speed is stored again as the reference rotational speed.

  Therefore, if a command rotational speed greater than the current rotational speed is input and the duty ratio does not reach 100%, the process proceeds to STEP 101, STEP 102, STEP 103, STEP 104, STEP 105, STEP 106, STEP 110, and the rotational speed control means 108 sets the duty ratio. By gradually increasing the rotation speed of the DC motor 104, if the rotation speed calculation result is the same as the reference rotation speed, the process proceeds to STEP 101, STEP 102, STEP 103, STEP 104, STEP 108, STEP 109, STEP 110, and the rotation speed control. The means 108 does not change the duty ratio and maintains the rotational speed of the DC motor 104 at the reference rotational speed.

  When the duty ratio reaches 100%, the process proceeds to STEP 101, STEP 102, STEP 103, STEP 104, STEP 105, STEP 107, STEP 120, STEP 110, the reference rotation speed is lower than the rotation speed calculated by the rotation speed calculation means 109, and the rotation speed Since the rotation speed closest to the number is set as the selected rotation speed and the timer 117 is ON, the process returns to STEP 130 and STEP 102 and proceeds to STEP 103. In STEP 104, the reference rotation speed is lower than the rotation speed calculated by the rotation speed calculation means 109. Therefore, the process proceeds to STEP 108, the process proceeds to STEP 108 and STEP 109, the duty ratio is decreased, and the rotation speed control means 108 decreases the rotation speed of the DC motor 104 by gradually decreasing the duty ratio.

  If the reference rotation speed and the rotation speed calculation result are the same, the process proceeds without passing through STEP 102, STEP 103, STEP 108, STEP 110 and STEP 9, and the rotation speed control means 108 does not change the duty ratio, and the rotation speed of the DC motor 104 is set as a reference. Maintain the speed.

  Further, if the reference rotational speed is set lower than the rotational speed calculated by the rotational speed calculation means 109 in STEP 110 and set to the rotational speed closest to the rotational speed, the routine proceeds to STEP 130, and the duty is determined in STEP 111 during the operation of the timer 117. Since the value is not judged, the compressor 115 is operated at the changed rotational speed for a certain period of time during which the timer 117 is operating.

  If such an operation is continued, the operation of the timer 117 is finished, the inside of the refrigerator is cooled, the overload state is gradually eliminated, and the rotation speed is maintained even if the voltage applied to the DC motor 104 is decreased. become able to.

  Therefore, if the reference rotation speed is set lower than the rotation speed calculated by the rotation speed calculation means 109 in STEP 110 and the rotation speed closest to the rotation speed is set, the operation proceeds to STEP 130 and the operation of the timer 117 is completed. For example, if the duty ratio is 90% or less, the process proceeds to STEP 101 where the reference rotational speed is set to the command rotational speed and normal control is performed.

  In this embodiment, the duty ratio is set to 90% or less, but this value is used to calculate a duty ratio that allows the DC motor 104 to operate at the commanded speed even if the reference speed is returned to the commanded speed by experiment or the like. .

  When a command rotational speed smaller than the current rotational speed is input, the process proceeds to STEP 101, STEP 102, STEP 103, STEP 104, STEP 108, STEP 109, STEP 110, and the rotational speed control means 108 gradually decreases the duty ratio. If the rotational speed of the DC motor 104 is lowered and the reference rotational speed and the rotational speed calculation result are the same, the process proceeds to STEP 101, STEP 102, STEP 103, STEP 108, STEP 110, and the rotational speed control means 108 does not change the duty ratio. The rotation speed of the motor 104 is maintained at the reference rotation speed.

  Therefore, normally, the duty ratio is controlled to be increased or decreased so that the rotation speed of the DC motor 104 becomes the same as the command rotation speed. When the duty ratio reaches 100%, the compressor 115 is rotated at the resonance rotation speed. By controlling for a certain time so as not to occur, it is possible to eliminate fluctuating sound due to fluctuations in the rotation speed of the compressor 115.

  As described above, the compressor control device according to the present invention has a function of eliminating the fluctuation sound due to the change in the operation speed of the compressor, and thus is useful for the inverter drive device and the refrigerator control of the compressor. .

The circuit diagram of the control apparatus of the compressor in Embodiment 1 of this invention Flowchart of compressor control apparatus in the embodiment Circuit diagram of conventional compressor control device Flowchart of conventional compressor control device

Explanation of symbols

103 Inverter circuit 104 DC motor (motor)
104a rotor 106 position detection means 107 commutation means 108 rotation speed control means 109 rotation speed calculation means 111 rotation speed comparison means 113 drive means 114 set rotation speed storage means 117 timer

Claims (3)

An inverter circuit; position detecting means for detecting a position of a rotor of the motor and generating a position detection signal; and an operation of the inverter circuit based on an output of the position detecting means to output a commutation pulse. A rotating speed control means for controlling a voltage by adjusting a duty ratio which is a ratio of an on-time in a carrier cycle in order to make the rotation speed of the compressor variable, an output of the commutation means and the rotation Drive means for operating the inverter circuit by the output of the number control means, rotation speed calculation means for calculating the rotation speed of the motor from the output of the position detection means, and the rotation speed at which the motor can be operated are stored. The set rotational speed storage means compares the rotational speed of the command rotational speed with the rotational speed of the motor calculated by the rotational speed computing means, and the rotational speed of the motor becomes the command rotational speed. In the compressor control device comprising: a rotation speed comparison means that outputs to the rotation speed control means; and a timer that operates when a duty ratio output from the rotation speed control means reaches 100%, the rotation speed control means When the duty ratio output from the motor reaches 100%, a rotation speed lower than the command rotation speed is selected from the set rotation speed stored in the set rotation speed storage means, the compressor is operated, and the timer is set to the set value. After that, when the duty ratio output from the rotation speed control means becomes a predetermined value or less, the command rotation speed is compared with the rotation speed calculated by the rotation speed calculation means, and the operation at the same rotation speed is continued for a certain time. The control apparatus of the compressor characterized by performing control which reduces the fluctuation sound of a compressor by this. 2. The compressor according to claim 1, wherein when the duty ratio output from the rotational speed control means reaches 100%, a rotational speed lower than the command rotational speed and equal to or lower than the rotational speed calculated by the rotational speed calculation means is selected from the set rotational speeds. Control device. The compressor control device according to claim 1 or 2, which controls a refrigerator.

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