JP2006322681A - Compressor operation control apparatus and operation control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform forced stop control of compressor operation for the purpose of saving power consumption at a preferable timing in consideration of an actual operation state.
SOLUTION: The operation of a compressor 10 in an air conditioner 2 is forcibly stopped for a specific period to save power. The forced stop is started at a timing based on a point in time immediately after the start of the operation of the compressor 10 when the heavy load operation having a large operation load is shifted to a light load operation in which a parameter corresponding to the operation load is not more than a certain value.
[Selection] Figure 1

Description

  The present invention relates to a technique for controlling the operation of a compressor for the purpose of reducing the power consumption of the compressor provided in a temperature control device such as a refrigerator or an air conditioner.

In temperature control devices such as refrigerators and air conditioners, the amount of power consumed by the compressor (compressor) built in the device is large, so that the operation of the compressor is forcibly stopped for a certain period of time in order to save it. Demand control may be introduced. As a specific method of this demand control, for example, Patent Document 1 discloses a method for forcibly stopping the operation of the compressor for a preset time every predetermined control cycle.
Japanese Patent No. 3037939

  In the temperature adjusting device, the on / off control of the operation of the compressor is executed so that the actual temperature to be adjusted (for example, room temperature) approaches a preset target temperature. What is the on / off control for the temperature adjustment? If the compressor operation is forcibly stopped every time a certain control period elapses at a timing that is completely unrelated, depending on the operation state of the compressor at the time of the forced stop start, the compressor may be overloaded. May be adversely affected, and the operating temperature may be adversely affected.

  For example, in an air conditioner, if the forced stop is performed immediately after the room temperature is higher than the target temperature by a certain level and the compressor starts operating, the room temperature cannot be brought close to the target temperature and the compressor is turned on / off frequently. This increases the risk of shortening its life. In addition, when the forced stop is executed immediately before the operation of the compressor is resumed from the resting state, the resting period of the compressor is unreasonably postponed, making it difficult to perform appropriate temperature control.

  As means for eliminating such inconvenience, the above-mentioned Patent Document 1 presupposes that the forced stop control is executed every predetermined control cycle, and even if the control cycle comes, it is constant after the compressor is started. There is disclosed a method for waiting until the time elapses without performing the forced stop, but also in this method, the time for waiting for the forced stop is determined to be a fixed time. It is difficult to forcibly stop the compressor at an appropriate timing in consideration of various operating conditions (for example, operating temperature and operating load).

  In view of such circumstances, an object of the present invention is to provide a technique capable of performing forced stop control of compressor operation for the purpose of saving power consumption at a preferable timing in consideration of actual operation conditions.

  As means for solving the above-mentioned problems, the present invention is provided in a temperature adjustment device including a compressor and temperature control means for controlling the operation load of the compressor so that the actual temperature to be adjusted approaches the target temperature. An operation control device for a compressor for forcibly stopping the operation of the compressor for a specific period so as to reduce its power consumption, an operation state monitoring unit for monitoring a parameter corresponding to the operation load of the compressor, and the operation of the compressor And a stop control unit that forcibly stops the engine for a predetermined forced stop time, and the parameter corresponding to the operation load from a heavy load operation with a large operation load immediately after the start of operation of the compressor is below a certain level. Compulsory stop control of compressor operation at timing based on the point of transition to light load operation It is intended to start.

  The present invention is also a compressor operation control method for stopping a compressor operation for a predetermined time so as to reduce power consumption of a temperature control device including the compressor, and monitoring a parameter corresponding to the operation load of the compressor. Immediately after the start of operation of the compressor, forced stop control of the operation of the compressor is performed at a timing based on the transition from heavy load operation with a large operation load to light load operation in which a parameter corresponding to the operation load is below a certain level. It is what is started.

  According to the above configuration, instead of starting the forced stop control of the compressor operation at every constant control period as in the past, the time when the operation of the compressor shifts from the heavy load operation to the light load operation, that is, actually Since the difference between the temperature to be adjusted and the target temperature becomes smaller and the compressor operating state enters the stable period, the forced stop control is started at the timing based on the transition point. The forced stop control can be executed without giving an excessive load to the compressor and at an appropriate timing that can ensure good temperature control.

  Furthermore, if the operation state of the compressor corresponds to a specific stop control stop condition, if the forced stop control of the compressor operation is stopped, it is possible to realize the compressor operation control more appropriately. become.

  For example, when the operation state of the compressor is determined to be abnormal, or when the abnormal state continues for a certain period or longer, it is difficult to achieve good temperature adjustment. It is preferable to give priority to temperature control by stopping the operation.

  Various methods for determining the operation abnormality can be set. For example, when monitoring the magnitude or frequency of the motor current flowing through the motor driving the compressor as a parameter corresponding to the operation load of the compressor, the magnitude of the motor current is determined. When the discharge pressure of the compressor is reduced at a certain rate or more with respect to the reference pressure set corresponding to the frequency or the frequency, it is possible to determine that the operation of the compressor is abnormal.

  Further, when the compressor idle period before the compressor operation is longer than a preset reference time, it is expected that the power consumption is originally low and the compressor operation time is also short. Therefore, in this case, by discontinuing the forced stop control, the burden on the compressor due to the on / off switching of the operation of the compressor can be reduced.

  The forced stop time can be set as appropriate, but when the heavy load operation period from the start of the operation of the compressor to the shift to the light load operation is long, the actual adjustment target temperature and the target temperature Therefore, it is more preferable to perform correction to shorten the forced stop time of the compressor as the heavy load operation period is longer.

  As described above, the present invention starts the forced stop control of the operation at a timing based on the time point when the operation of the compressor shifts from the heavy load operation to the light load operation. There is an effect that the forced stop control of the compressor operation can be performed at a preferable timing in consideration of the actual operation state.

  A preferred embodiment of the present invention will be described with reference to the drawings. In this embodiment, an example is shown in which the present invention is applied to the air conditioner 2 as a temperature control device, but the present invention can also be applied to other temperature control devices, for example, refrigerators.

  FIG. 1 shows an air conditioning system including the air conditioner 2. The air conditioner 2 includes an operation control device 4 according to the present invention, a condition setting state indicator 6, and an external communicator 8. It is attached.

  The air conditioner 2 includes a compressor (compressor) 10, an outdoor unit 12, and an indoor unit 14, which are interconnected by necessary piping and electrical wiring. The motor 20 that drives the compressor 10 is supplied with 200-V three-phase AC voltages R, S, and T, and in the middle of the power supply wiring, a current sensor 22 that detects a current I that flows through the motor 20, A circuit breaker 24 comprising a relay for forcibly cutting off the current (that is, forcibly stopping the operation of the compressor 10) is provided. Here, the motor current I detected by the current sensor 22 is used for operation control of the compressor in the operation control device 4 as “a parameter corresponding to the operation load of the compressor” in the present invention.

  The indoor unit 14 is provided with a temperature sensor 16, and the detection signal is input to a microcomputer (temperature control means) provided in the outdoor unit 12. This microcomputer controls the operation load of the compressor 10 (that is, the drive of the motor 20) so that the detected temperature approaches the preset target temperature. In this embodiment, when the compressor 10 is started, a heavy load operation with a large motor current is performed, and thereafter, when the difference between the detected temperature and the target temperature becomes equal to or less than a certain value, the motor current is decreased (light load). The operation control for stopping the driving of the compressor 10 is executed when the detected temperature reaches the target temperature or a temperature lower than the target temperature by a certain level or more.

  The air conditioner 2 also includes a pressure sensor 18 that detects the pressure P at which the compressor 10 discharges the refrigerant gas.

  In the present invention, the compressor discharge pressure P can be adopted as the “parameter corresponding to the compressor operating load”. However, the discharge pressure P is caused by deterioration of the performance of the compressor 10 as described later. Therefore, it is more preferable to adopt the magnitude of the motor current I or a value corresponding to the parameter as the parameter.

  The operation control device 4 executes a forced stop control of the operation of the compressor 10 for the purpose of power saving separately from the operation control of the compressor 10 by the outdoor unit 12, that is, the on / off control of the operation of the compressor 10 for temperature adjustment. There is a configuration as shown in FIG.

  That is, the operation control device 4 includes a central processing unit 30. The central control device 30 includes a power supply device 31, a control state switching device 32, an operation state monitoring device 33, a compressor control output device 34, an external communication control device 35, a memory. 36, a status indicator 37, and a time measuring device (timer) 38 are connected.

  The power supply device 31 converts an input AC voltage (for example, 100 V) into a DC voltage, and supplies the power to the central processing unit 30 and the like.

  The control state switching device 32 is for switching the central control device 30 between a control execution mode and a control non-execution mode manually (for example, switch operation).

  The operating state monitoring device 33 uses the temperature detected by the temperature sensor 16, the compressor discharge pressure P detected by the pressure sensor 18, and the current sensor 22 as parameters for grasping the operating state of the compressor 10. The detected compressor driving motor current I is monitored.

  The central processing unit 30 stores each parameter monitored by the operation state monitoring device 33 and the memory 36 (set in advance) only when the control state switching device 32 switches to the control execution mode. ) Based on the control conditions and the timing pulse signal output from the timing device 38, a control signal for forcibly stopping the operation of the compressor 10 at an appropriate timing is created. This signal is output from the compressor control output device 34 to the circuit breaker 24, and the coil of the relay constituting the circuit breaker 24 is energized to interrupt the power supply path to the motor 20.

  In addition, the central processing unit 30 displays the current operation state and control state on the state display 37, and when an abnormality is recognized in the operation of the compressor 10, a warning display to that effect is displayed on the state display 37. Let it be done.

  Further, the central processing unit 30 according to this embodiment communicates with the overall control device together with other air conditioners through the external communication control device 35 and the external communication device 8 shown in FIG. This integrated control device randomly determines the priority order of forced stop so that a plurality of air conditioners are not forcibly stopped at the same time, and the air conditioners are forcibly stopped one by one in that order. A command is sent to the operation control device 4 of the device.

  Next, the operation control of the compressor 10 performed in this system will be described.

A. Normal Operation Operation First, a normal operation operation (temperature adjustment operation) when the forced stop control by the operation control device 4 is not executed will be described with reference to FIGS.

  The microcomputer incorporated in the outdoor unit 12 starts the operation of the compressor 10 when the temperature detected by the temperature sensor 16 provided in the indoor unit 14 becomes higher than the target temperature by a certain level.

  At this time, as shown in FIG. 3, the magnitude of the motor current I flowing through the compressor driving motor 20 is raised from the current I0 at the time of operation suspension to a predetermined current I1 larger than the current I0. The discharge pressure P of 10 also shifts from the pressure P0 at rest to a pressure P1 higher than that. This initial period is in the heavy load operation state, the current I1 is large, and the pressure P1 is also high.

  Thereafter, when the difference between the actual temperature and the target temperature becomes a certain value or less, the magnitude of the motor current I is switched to the current I2 smaller than the current I1, and the discharge pressure of the compressor 10 is also changed from the pressure P1. The pressure gradually decreases and converges to a lower pressure P2. After shifting to the light load operation in this manner, the operation of the compressor 10 is stopped again when the actual temperature is equal to or lower than the target temperature by a certain level.

  In FIG. 3, for the sake of convenience, the motor current I is drawn so as to fall linearly from I1 to I2, but the actual motor current I falls in a curve from the current I1 to the current I2.

  In this embodiment, as will be described later, when the magnitude of the motor current I becomes equal to or less than a preset threshold value, it is determined that the heavy load operation is shifted to the light load operation. The operation time T1 for heavy load operation and the operation time T2 for light load operation vary greatly depending on the temperature during the operation and the state of the compressor 10. For example, when compared with the operation state at a standard temperature in summer as shown in FIG. 4A, in the period in which the temperature is relatively low and the difference from the target temperature is small as in the spring and autumn, FIG. As shown in FIG. 4, the operation times T1 and T2 are shortened, and conversely, the operation suspension time T3 is increased. On the other hand, when the difference between the actual temperature and the target temperature is large, such as during extreme heat, or when the performance of the compressor 10 is deteriorating, the operating times T1 and T2 are as shown in FIG. On the contrary, the operation suspension time T4 is shortened.

  Focusing on the relationship between the motor current I and the compressor discharge pressure P, when the compressor 10 is operating normally, the compressor discharge pressure P corresponding to the specific motor current I as shown by the solid line in FIG. Is maintained at a high level as indicated by the one-dot chain line in FIG. 1, but the discharge pressure P corresponding to the motor current I gradually decreases as indicated by the two-dot chain line in FIG. . Therefore, in this embodiment, the pressure indicated by the one-dot chain line is set as a reference pressure, and it is determined whether or not the operation of the compressor 10 is abnormal based on the actual pressure decrease rate with respect to the reference pressure. The central controller 30 is configured.

  Next, the content of the operation control performed by this operation control apparatus 4 is demonstrated along the flowchart of FIG.6 and FIG.7.

  Step S0 in FIG. 6: The mode selected by the control state switching device 32 is confirmed. Only when the control execution mode is selected (YES in step S0), the following control is executed.

  Step S1: The operation history is judged at regular intervals and stored in the memory. The record of the operation history is used for air conditioner maintenance, abnormality warning, etc., but is not essential in the present invention.

  Step S2: It is determined whether or not the operation of the compressor 10 has been started. Until the operation of the compressor 10 is started (NO in step S2), the continuous pause time T3 is added (step S3).

  Step S4: After starting the compressor operation (YES in Step S2), the time point when the heavy load operation is shifted to the light load operation is monitored. In this embodiment, a change in the magnitude of the motor current I is monitored, and when the magnitude of the motor current I falls below a preset threshold value, a transition is made from heavy load operation to light load operation. It is judged that The threshold value is appropriately set in a range that is less than the current I1 immediately after the start of the operation of the compressor 10 as shown in FIG.

  Step S5: It is determined whether or not the operating state of the compressor 10 is abnormal. In this embodiment, it is determined that there is an abnormality when any of the following is true.

  a) When the heavy load operation time T1 exceeds a preset allowable time T10.

  b) When the rate of decrease in the actual compressor discharge pressure P detected by the pressure sensor 18 is outside the preset allowable range. As the pressure drop rate, the ratio of the detected pressure P to the reference pressure (one-dot chain line in FIG. 5) set corresponding to the motor current I is calculated. For the reference pressure corresponding to the motor current I, for example, the relationship between the motor current I and the reference pressure may be stored in the memory 36 as a map.

  Steps S6 to S8: When it is determined that the operation of the compressor 10 is abnormal (YES in Step S5), a warning to that effect is given (Step S6). Further, when the operation abnormality has occurred a predetermined number of times (YES in step S7), it is determined that the performance of the compressor 10 has been significantly deteriorated, and the compressor operation is not performed in order to extend its life and maintain an appropriate operation temperature. The forced stop control is stopped (step S8).

  Note that, depending on the abnormal operation condition, the forced stop control may be canceled immediately after the abnormality is determined in step S5.

  Step S9: When it is determined that the operation abnormality has not occurred (NO in step S5), or when the number of occurrences of the operation abnormality is less than the predetermined number (NO in step S7), the previous operation suspension It is determined whether or not the time T3 (ie, the period from the start of the previous stop of the operation of the compressor 10 to the start of the operation of the current compressor 10) T3 exceeds a preset reference time T30.

  If T3> T30 (YES in step S9), the operation suspension time T3 is long and sufficient power is saved, and the light load operation is predicted to be completed in a short time because the temperature is relatively low. Therefore, the forced stop control of the compressor operation is stopped (step S8). On the other hand, if T3 ≦ T30 (NO in step S9), the operation forced stop control execution routine is entered (step S10).

  The contents of this routine are shown in FIG. First, a time (forced stop time) T4 for forcibly stopping the operation of the compressor 10 is calculated. Specifically, the basic stop time T40 is read (step S11), and then the correction value t1 (step S12) based on the heavy load operation time T1 and the correction value t2 (step S13) for giving the fluctuation 1 / f. Then, T4 = T40−t1 + t2 is calculated as the final forced stop time (step S14).

  Here, the correction value t1 is set to a larger value as the heavy load operation time T1 is longer. That is, when the heavy load operation time T1 is long, it is presumed that the air temperature is relatively high or the performance of the compressor 10 is deteriorating. Therefore, the forcing to ensure the target temperature over the power saving is prioritized. Correction for shortening the stop time T4 is performed. On the other hand, the correction value t2 is for giving a 1 / f fluctuation to the forced stop time T4 so that the human body does not feel stress.

  Thereafter, when a predetermined time has elapsed from the time of shifting to the light load operation (YES in step S15), the forced stop control of the operation of the compressor 10 is started in principle (step S17), and the above-described operation stop time T4 has elapsed. Later (YES in step S18), the forced stop is canceled (step S19). In this way, by setting the start timing of forced stop control with reference to the transition point from heavy load operation to light load operation, compared to the case where forced stop control is executed every fixed control period as in the past, It is possible to perform an appropriate forced stop control in accordance with the actual operation state of the compressor 10.

  However, in this embodiment, the priority order of forced stop is determined by the central control unit (not shown) so that a plurality of air conditioners are not forcibly stopped at the same time. Therefore, a predetermined time has elapsed since the transition to the light load operation. Even so, until the priority order arrives (NO in step S16), the process waits without starting the forced stop control, and executes the forced stop control when the order arrives (YES in step S16). To.

  As described above, in the present invention, the start timing of the operation stop control only needs to be based on the transition point from the heavy load operation to the light load operation, and the specific timing can be appropriately set within the range. For example, the forced operation stop control may be started immediately when it is determined that the heavy load operation has shifted to the light load operation, or a parameter (for example, the motor current I) corresponding to the operation load is constant. Forcible stop control may be started when the rate of change with time falls below a certain level after falling to the threshold value.

  The air conditioner 2 controls the magnitude of the motor current I as an operation load of the compressor 10. When the difference between the actual detected temperature and the target temperature becomes a certain value or less, the motor current I Although the magnitude (absolute value) is reduced, the frequency of the air conditioner or the like that controls the frequency of the motor current I as the operating load may be monitored.

  That is, it is an air conditioner in which the frequency of the motor current is inverter-controlled by temperature, and control is performed to lower the frequency of the motor current when the difference between the actual detected temperature and the target temperature becomes less than a certain value. For temperature control equipment, the frequency of the motor current is monitored, and when the frequency falls below a preset threshold value, it is determined that the operation has shifted to light load operation. The forced operation stop control may be executed at the same timing.

  Further, the control of the operating load of the compressor 10 including the magnitude and frequency of the motor current I is not limited to only based on the difference between the actual detected temperature and the target temperature. As for the temperature control device that performs the combined control of the operation load while taking into account the discharge pressure of the compressor, the appropriate forced stop control can be executed by monitoring the parameter corresponding to the operation load of the compressor 10 as described above. it can.

It is a block diagram which shows the air-conditioning system provided with the operation control apparatus of the compressor which concerns on embodiment of this invention. It is a block diagram which shows the structure of the said operation control apparatus. It is a graph which shows the time change of the motor current for the compressor drive in the said air conditioning system. (A) is a graph showing the time change of the standard motor current, (b) is a graph showing the time change of the motor current when the operation time of the compressor is short and the operation stop time is long, and (c) is a compressor. It is a graph which shows the time change of the said motor current when the driving | operation time of this is long and driving | operation stop time is short. It is a graph which shows the relationship between the motor current for driving a compressor, and compressor discharge pressure. It is a flowchart which shows the content of the operation forced stop control performed by the said operation control apparatus. It is a flowchart which shows the content of the forced stop control execution routine shown by FIG.

Explanation of symbols

2 Air Conditioning Equipment 4 Operation Control Device 10 Compressor 18 Pressure Sensor 20 Motor 22 Current Sensor 24 Breaker 30 Central Controller (Stop Control Unit)
33 Operation state monitoring device 34 Compressor output control device

Claims (8)

  Provided in a temperature control device that includes a compressor and temperature control means for controlling the operation load of the compressor so that the actual temperature to be adjusted approaches the target temperature, and specifies the operation of the compressor so as to reduce its power consumption An operation control device for a compressor for forcibly stopping only for a period, an operation state monitoring unit for monitoring a parameter corresponding to the operation load of the compressor, and a stop control unit for forcibly stopping the operation of the compressor for a predetermined forcible stop time; The stop control unit immediately after the start of operation of the compressor at a timing based on a time point when a heavy load operation having a large operation load is shifted to a light load operation in which a parameter corresponding to the operation load is equal to or less than a certain value. Compressor operation control characterized by starting forced stop control of compressor operation Apparatus.   2. The compressor operation control device according to claim 1, wherein the stop control unit stops the forced stop control of the compressor operation when the operation state of the compressor corresponds to a specific stop control stop condition. Compressor operation control device.   3. The compressor operation control device according to claim 2, wherein the stop control stop condition includes a condition that the operation state of the compressor is determined to be abnormal, or a condition that the abnormal state continues for a certain period or more. Compressor operation control device characterized by the above.   In the compressor operation control device according to claim 3, the operation state monitoring unit monitors the magnitude or frequency of the motor current flowing in the motor driving the compressor as a parameter corresponding to the operation load of the compressor, The stop control unit determines that the operation of the compressor is abnormal when the discharge pressure of the compressor is decreasing at a certain ratio or more with respect to a reference pressure set corresponding to the magnitude or frequency of the motor current. An operation control device for a compressor, characterized in that:   3. The operation control apparatus for a compressor according to claim 2, wherein the stop control stop condition includes a condition that a pause period of the compressor before the operation of the compressor is started is equal to or longer than a preset reference time. An operation control device for a compressor.   The operation control apparatus for a compressor according to any one of claims 1 to 5, wherein the stop control unit includes the longer the heavy load operation period from the start of operation of the compressor to the transition to the light load operation. An operation control apparatus for a compressor, which corrects the forced stop time of the compressor.   A compressor that stops the operation of the compressor for a predetermined time so as to reduce the power consumption of the temperature control device including the compressor and a temperature control unit that controls the operation load of the compressor so that the actual temperature to be adjusted approaches the target temperature. The operation control method is for monitoring a parameter corresponding to the operation load of the compressor, and immediately after the start of operation of the compressor, a heavy load operation having a large operation load and a parameter corresponding to the operation load being a constant load or less An operation control method for a compressor, wherein forced stop control of the operation of the compressor is started at a timing based on a time point at which the operation is shifted.   8. The compressor operation control device according to claim 7, wherein when the operation state of the compressor corresponds to a specific stop control stop condition, the forced stop control of the compressor operation is stopped. .

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