Compressor and method for controlling same

Abstract

This compressor is capable of effectively reducing a stopping pressure in accordance with operation cycle time regardless of whether or not continuous operation by an unload function or a variable speed function by an inverter is included. A compressor 100 comprises an electric motor 104, a compressor body 103 that is driven by the electric motor 104 and that generates compressed gas 109, a tank 10 that stores the compressed gas 109 generated by the compressor body 103, a pressure detector 112 that detects the pressure of the compressed gas 109 in the tank 107, and a control unit 115 that controls, in accordance with a detection result from the pressure detector 112, electricity to be supplied to the electric motor 104. The control unit 115 determines whether or not a pressure increase / decrease cycle (TOFF+TON), in which the pressure reaches a stopping pressure 202, decreases to a starting pressure 204, and reaches the stopping pressure 202, exceeds a first cycle threshold value 210, and, when the pressure increase / decrease cycle exceeds the first cycle threshold value 210, lowers the stopping pressure by a first pressure change value (PECO or 2PECO).

Description

Compressor and control method thereof

[0001] The present invention relates to a compressor and a control method thereof.

[0002] Gas compressors that generate compressed gas and are used as power sources on production lines and as air sources for machine tools, presses, air blowers, etc. are known. Packaged gas compressors are also available that include the compressor itself, multiple motors that drive it, and a control circuit, operation panel, and other components all housed in a single package to save space. Reducing the power consumption of such gas compressors is required, and one solution is to lower the shutdown pressure at which the gas compressor stops operating.

[0003] Background art of the present invention includes Patent Documents 1 and 2.

[0004] In Patent Document 1, a reciprocating compressor having an unloading function is equipped with a control for switching between intermittent operation control and continuous operation control so that the operation cycle time is equal to or longer than a predetermined reference operation cycle time T0.

[0005] In Patent Document 2, a control is provided that can reduce the stop pressure according to calculations of the tank volume and air consumption.

[0006] JP 2013-117182 A JP 2012-154294 A

[0007] The compressor described in Patent Document 1 uses an unloading function to switch between intermittent operation control and continuous operation control to reduce the load on the compressor and reduce power consumption. However, the compressor described in Patent Document 1 stops the motor and the operation of the compressor body when the reference operation cycle time is reached, even if the stop pressure has not been reached, thereby reducing power consumption. However, this does not control to lower the stop pressure. Furthermore, because the stop pressure is not lowered, the stop pressure is not controlled to be increased again according to the operation cycle time.

[0008] Continuous operation control is not possible for compressors that do not have an unloading function or variable speed control using an inverter. Therefore, for compressors that do not have variable speed control, control is required to reduce power consumption by only intermittent operation control.

[0009] Furthermore, the technology described in Patent Document 2 does not control the stop pressure to be lowered by a fixed amount in accordance with the operation cycle time, which changes from time to time, nor does it control the stop pressure to be increased again in accordance with the operation cycle time after it has been lowered.

[0010] Since the stop pressure is changed only when the tank volume is changed, the stop pressure cannot be changed during normal use at other times, and there is room for reducing power consumption during normal use.

[0011] An object of the present invention is to provide a compressor and a control method thereof that can effectively reduce the stop pressure in accordance with the operation cycle time, regardless of whether the compressor has a continuous operation function using an unload function or a variable speed function using an inverter.

[0012] In order to achieve the above object, the present invention is configured as follows.

[0013] The compressor comprises an electric motor, a compressor main body driven by the electric motor to generate compressed gas, a tank to store the compressed gas generated by the compressor main body, a pressure detector to detect the pressure of the compressed gas in the tank, and a control unit to control the power supplied to the electric motor in accordance with the detection result of the pressure detector, wherein the control unit determines whether the pressure increase / decrease cycle from when the detection result of the pressure detector reaches a stop pressure, to when the pressure decreases to a start pressure, and to when the pressure again reaches the stop pressure, exceeds a first cycle threshold, and if the pressure increase / decrease cycle exceeds the first cycle threshold, reduces the stop pressure by a first pressure change value.

[0014] Also, there is provided a method for controlling a compressor, which is driven by an electric motor and generates compressed gas, storing the compressed gas generated by the compressor body in a tank, detecting the pressure of the compressed gas in the tank with a pressure detector, and controlling the power supplied to the electric motor in accordance with the detection result, wherein the detection result of the pressure detector reaches a stop pressure, then decreases to a start pressure, and a determination is made as to whether the pressure increase / decrease cycle until the stop pressure is reached again exceeds a first cycle threshold, and if the pressure increase / decrease cycle exceeds the first cycle threshold, the stop pressure is decreased by a first pressure change value.

[0015] According to the present invention, even if the compressor does not have continuous operation control using an unload function or variable speed control using an inverter, it is possible to realize a compressor and a control method thereof that can effectively reduce the stop pressure in accordance with the operation cycle time.

[0016] FIG. 1 is a conceptual diagram of an entire compressor according to a first embodiment of the present invention. FIG. 2 is a conceptual diagram showing a time waveform of pressure in a compressor according to an embodiment of the present invention. FIG. 3 is a functional block diagram of a control board (control unit) according to the first embodiment of the present invention. FIG. 4 is a conceptual diagram of an entire compressor according to a second embodiment of the present invention. FIG. 5 is a conceptual diagram showing a time waveform of pressure in a compressor according to the second embodiment of the present invention. FIG. 6 is a functional block diagram of a control board (control unit) according to a third embodiment of the present invention. FIG. 7 is a conceptual diagram showing an operating state flow of a compressor according to a fifth embodiment of the present invention. FIG. 8 is a conceptual diagram showing an operating state flow of a compressor according to a sixth embodiment of the present invention. FIG. 9 is a conceptual diagram showing an operating state flow of a compressor according to a modification of the sixth embodiment of the present invention. FIG. 10 is a conceptual diagram showing an operating state flow of a compressor according to a seventh embodiment of the present invention.

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0018] (First embodiment) In the first embodiment, a product will be described using as an example a product equipped with a scroll compressor in which a compression chamber is formed between a fixed scroll and an orbiting scroll, and air is compressed by orbiting motion, as a compression method of the compressor body.

[0019] 1 is a conceptual diagram of an entire compressor 100 according to a first embodiment of the present invention. This first embodiment is composed of a single-stage compressor body 103. Air 101 supplied from the outside of the compressor 100 to the inside passes through a filter 102 and is supplied to the compressor body 103. The compressor body 103 is driven by an electric motor 104, and the compressed air passes through a check valve 105, an aftercooler 106, a tank 107, and a dryer 108 and is supplied to the outside as compressed air (compressed gas) 109.

[0020] The compressor 100 operates and stops as a whole using a switch 110, and each part of the compressor 100 is controlled by a control board 111. The control board 111 issues a command to a magnet switch 113 in response to pressure detected by a pressure sensor (pressure detector) 112, thereby controlling the intermittent operation of the compressor main body 103.

[0021] The control board 111 and the magnet switch 113 form a control unit 115. The control unit 115 controls the power supplied to the electric motor 104 in accordance with the detection result of the pressure detector 112.

[0022] FIG. 2 is a conceptual diagram showing the time waveform of pressure in the compressor 100 according to the first embodiment of the present invention, where the vertical axis represents pressure and the horizontal axis represents time.

[0023] In FIG. 2, the compressor 100 starts operation at the start of operation time 201, and the pressure increases until it reaches a stop pressure (P ＭＡＸ After the compressor 100 is stopped, the pressure drops to the starting pressure (P ＭＩＮ ) 204 is the time until restarting, ＯＦＦ ) 205. Then, the stop pressure (P ＭＡＸ ) 202 is defined as the operation cycle time (T ＯＮ ) Count as 206.

[0024] These stop cycle times (T ＯＦＦ ) 205 and the operating cycle time (T ＯＮ ) 206 is added together (pressure increase / decrease cycle) and the resulting number is the ECO mode cycle time (T ＥＣＯ) 210 (first cycle threshold) ＯＦＦ +T ＯＮ >T ＥＣＯ ) and ECO mode cycle time (T ＥＣＯ If the stop cycle time (T ＯＦＦ ) 205 and the operation cycle time (T ＯＮ ) 206 is compared with the ON-OFF time determination formula 208 (T ＯＦＦ >T ＯＮ ) and then the pressure change value (P ＥＣＯ ) 209 for the next driving cycle time 206, and ＭＡＸ ) 203.

[0025] The post-change stop pressure (P' ＭＡＸ ) 203 is determined by the cycle time determination formula 207. ＥＣＯ ) 210, the stop pressure stabilization determination formula 211(T ＯＦＦ +T ＯＮ <C ＳＴ *T ＥＣＯ ) and the changed stop pressure (P' ＭＡＸ ) 203 is judged whether it is necessary to change it. ＳＴ *T ＥＣＯ is the second cycle threshold. ＳＴ is a tolerance that can be set arbitrarily, and can be set to within 5%, for example.

[0026] FIG. 3 is a conceptual diagram showing the operational flow of the compressor 100 according to the first embodiment of the present invention.

[0027] 3, control is started according to flow start step 301. Compression operation is started in compressor operation start step 302, and the process loops in ECO mode control step 303. When compression operation is started in start step 302, the control board 111 executes the flow shown in FIG.

[0028] Stop cycle time (T ＯＦＦ ) and operation cycle time (T ＯＮ ) is the ECO mode cycle time (T ＥＣＯ) is exceeded in the cycle time determination step 304 using the cycle time determination formula 207. ＯＦＦ ) and operation cycle time (T ＯＮ ) is the ECO mode cycle time (T ＥＣＯ If it exceeds the predetermined time, the ECO flag is set in the ECO flag setting step 308 and the process proceeds to the ON-OFF time determination step 309 .

[0029] In step 309, the stop cycle time (T ＯＦＦ ) and operation cycle time (T ＯＮ ) is compared using the ON-OFF time judgment formula 208. In step 309, the stop cycle time (T ＯＦＦ ) is the driving cycle time (T ＯＮ If the time is shorter than the predetermined time, proceed to step 310 and determine the modified stop pressure P'. ＭＡＸ Determine (P' ＭＡＸ =P ＭＡＸ -P ＥＣＯ ).

[0030] In step 309, the stop cycle time (T ＯＦＦ ) is the driving cycle time (T ＯＮ ), proceed to step 311, and determine the changed stop pressure P' ＭＡＸ Determine (P' ＭＡＸ =P ＭＡＸ -2P ＥＣＯ ).

[0031] After the processing of step 310 or step 311, the process proceeds to step 305, and the stop cycle time (T ＯＦＦ ) and operation cycle time (T ＯＮ ) is the total of the ECO mode cycle time (T ＥＣＯ ) with a stabilization coefficient (C ＳＴ If the answer is Yes (if it is less than the value obtained by multiplying the stop pressure (P ＭＡＸ ) or the changed stop pressure (P' ＭＡＸ ) value is not changed and the loop returns.

[0032] If the answer is No (not less than 0) in step 305, the process proceeds to step 306, where it is determined whether or not the ECO flag is set.

[0033] If the ECO flag is not set in step 306, the process returns to the loop. If the ECO flag is set in step 306, the process proceeds to step 312, where the modified stop pressure (P' ＭＡＸ ) is reset (P' ＭＡＸ =P' ＭＡＸ +P ＥＣＯ ). That is, the stop pressure (P ＭＡＸ ) to the pressure change value (P ＥＣＯ ) only.

[0034] Next, the process proceeds to step 313, where the changed stop pressure (P' ＭＡＸ ) is the initial stop pressure (P ＭＡＸ The stop pressure is then determined to be the same as the changed stop pressure (P'). ＭＡＸ ) is the initial stop pressure (P ＭＡＸ If the changed stop pressure (P') is equal to the changed stop pressure (P'), the process proceeds to step 314, where the ECO flag is cleared and the process returns to the loop. ＭＡＸ ) is the initial stop pressure (P ＭＡＸ ), the process returns to the loop.

[0035] The processing of steps 304 to 306 and 308 to 314 is looped while the compressor 100 is operating, and ends when the compressor 100 stops operating (step 307).

[0036] As is clear from the flowchart shown in FIG. ＯＦＦ +T ＯＮ ) is the ECO mode cycle time T ＥＣＯ Tolerance C ＳＴ If it is within, the stop pressure P ＭＡＸ The settings are configured not to be changed.

[0037] FIG. 4 is a functional block diagram of the control board 111 in the first embodiment.

[0038] In FIG. 4, the control board 111 includes a pressure control unit 1110 , a cycle time determination unit 1111 , a stop pressure change unit 1112 , and an ECO flag setting unit 1113 .

[0039] The pressure control unit 111 executes the operating state flow of the compressor 100 shown in Figure 3 based on the cycle time determined by the cycle time determination unit 1111, the stop pressure changed by the stop pressure change unit 1112, and the ECO flag setting unit 1113.

[0040] As described above, the first embodiment of the present invention is ＯＦＦ , T ＯＮ ) depending on the stop pressure P ＭＡＸ Since the compressor is configured to adjust the stop pressure in accordance with the operation cycle time, it is possible to realize a compressor and a control method thereof that can effectively reduce the stop pressure in accordance with the operation cycle time, regardless of whether or not the compressor has a continuous operation using an unloading function or a variable speed function using an inverter.

[0041] P ＥＣＯ or 2P ＥＣＯ The value changed to is called the first pressure change value, P ＥＣＯ The changed value is defined as a second pressure change value.

[0042] In the above-described example, the control unit 115 increases the stop pressure by a predetermined value when the pressure increase / decrease cycle is equal to or shorter than a predetermined time. However, Example 1 also includes a configuration in which the stop pressure is divided into a plurality of patterns based on the ratio between the stop cycle time and the operation cycle time of the pressure increase / decrease cycle, and the stop pressure is increased by a predetermined value set for each pattern.

[0043] The stabilization coefficient (C ＳＴ ) can be set arbitrarily for each product (compressor).

[0044] The control unit 115 may also include an inverter machine or a constant speed machine.

[0045] Second Embodiment Next, a second embodiment of the present invention will be described.

[0046] The second embodiment is an example in which, in the case of a compressor 100 equipped with an inverter, the operation cycle time of continuous operation control is counted as a stop cycle time to reduce power consumption.

[0047] FIG. 5 is a conceptual diagram of the entire compressor 100A according to the second embodiment of the present invention.

[0048] The compressor 100 according to the first embodiment shown in FIG. 1 is a constant speed compressor, but the compressor 100A according to the second embodiment does not include the magnet switch 113, and the control board 111A also functions as an inverter, and a signal is supplied from the control board 111A to the electric motor 104.

[0049] In the first embodiment, the control board 111 and the magnet switch 113 constitute the control unit 115, but in the second embodiment, the control board 111A, which also serves as an inverter, corresponds to the control unit 115.

[0050] FIG. 6 is a conceptual diagram showing a time waveform of pressure in the compressor 100A according to the second embodiment of the present invention, where the vertical axis indicates time and the horizontal axis indicates time.

[0051] In Fig. 6, the dashed line is the waveform of the rotation speed in the case of the motor controlled by the control board (also serving as an inverter) 111A, the broken line is the waveform of the pressure of the constant speed machine (Example 1), and the solid line is the waveform of the pressure of the control board 111A (Example 2). The waveform of the pressure of the constant speed machine (Example 1) (broken line) is ＯＦＦ ) 205 and 206 operation cycle time (T ＯＮ ) 206 and onwards, the waveform of the pressure is the same as that of the inverter machine (Example 2).

[0052] As shown by the dashed line in Figure 6, when the electric motor 104 is started, the rotation speed is increased at maximum acceleration in order to generate compressed gas. Thereafter, the rotation speed is changed according to the pressure, and the amount of compressed gas to be generated is adjusted.

[0053] When the rotation speed of the electric motor 104 is lower than the set lower limit value RS ＭＩＮ When the rotation speed reaches 213, the rotation speed is not decreased any more and the rotation is stopped. This is because the minimum rotation speed (lower limit value RS ＭＩＮ 213) is set.

[0054] Lower limit RS ＭＩＮ Even when operating at 213, the pressure is ＭＡＸ When the pressure reaches P, the rotation of the motor 104 is stopped. ＭＩＮ Wait for it to become.

[0055] The operating state flow of the compressor 103 is the same as that of the first embodiment shown in Fig. 3. The functional blocks of the control board 111A (excluding the inverter) are the same as those of the first embodiment shown in Fig. 4 (excluding the magnet switch 113).

[0056] In the second embodiment as well, the pressure of the compressor 103 repeatedly changes between the stop pressure and the return pressure, so that it is possible to achieve energy savings by using the cycle time as in the first embodiment.

[0057] In other words, according to the second embodiment, it is possible to realize a compressor and a control method thereof that can effectively reduce the stop pressure in accordance with the operation cycle time, regardless of whether or not the compressor has a continuous operation function using an unload function or a variable speed function using an inverter.

[0058] Third Embodiment Next, a third embodiment of the present invention will be described.

[0059] 7 is a functional block diagram of the control board 111 in the third embodiment. The difference between the functional block in the first embodiment shown in FIG. 4 and the functional block shown in FIG. 7 is that in FIG. 7, a part or all of the judgment formulas can be invalidated and parameters (first cycle threshold value 210, stabilization coefficient C ＳＴ , the first pressure change value (P ＥＣＯ or 2P ＥＣＯ ) Second pressure change value (P ＥＣＯ ), ECO mode cycle time T ＥＣＯ ) to any value.

[0060] Any user setting can appropriately modify the operation of the compressor 100 .

[0061] Other configurations and operations are the same as those in the first or second embodiment.

[0062] According to the third embodiment, in addition to the same effects as those of the first embodiment, an effect that the user can appropriately modify the operation of the compressor 100 can be obtained.

[0063] Fourth Embodiment Next, a fourth embodiment of the present invention will be described.

[0064] In Examples 1 and 2, the stop cycle time (T ＯＦＦ ) 205 and the operation cycle time (T ＯＮ ) 206 are distinguished and compared with each other for judgment.

[0065] In contrast, in Example 4, the stop cycle time (T ＯＦＦ ) 205 and the operation cycle time (T ＯＮ ) 206 without distinguishing between the cycle time (stop cycle time (T ＯＦＦ ) 205 + operation cycle time (T ＯＮ ) 206) and ECO mode cycle time (T ＥＣＯ ) 210 for simple control.

[0066] The other configurations and operations are the same as those in the first or second embodiment.

[0067] According to the fourth embodiment, even for a compressor that can be satisfactorily controlled simply, it is possible to realize a compressor and a control method thereof that can effectively reduce the stop pressure in accordance with the operation cycle time, regardless of whether the compressor has a continuous operation function using an unloading function or a variable speed function using an inverter.

[0068] Fifth Embodiment Next, a fifth embodiment of the present invention will be described.

[0069] In Example 1, the stop cycle time (T ＯＦＦ ) and operation cycle time (T ＯＮ ), whereas Example 5 is an example in which the determination is not made based on a single pressure increase / decrease cycle, but rather the time of multiple pressure increase / decrease cycles is averaged and then it is determined whether or not the first cycle threshold value 210 is exceeded.

[0070] FIG. 8 is a conceptual diagram showing the operational state flow of a compressor according to a fifth embodiment of the present invention.

[0071] The difference between the operating state flow of the third embodiment shown in Fig. 8 and the operating state flow of the first embodiment shown in Fig. 3 is that the flow of Fig. 7 adds a multiple cycle execution step 303A and an averaging processing step 303B between steps 303 and 304 of the flow of Fig. 3. The other steps of Fig. 8 are the same as those of Fig. 3.

[0072] In step 303A, multiple cycles are executed, and in step 303B, the stop cycle time (T ＯＦＦ ) and the operating cycle time (T ＯＮ ) and the average value of the calculated average value is used in the subsequent steps to calculate the stop cycle time (T ＯＦＦ ) and operation cycle time (T ＯＮ ) is used as

[0073] The number of cycles can be set to any value equal to or greater than two.

[0074] According to the fifth embodiment, it is possible to obtain the same effect as that of the first embodiment, and in addition, by leveling out the fluctuations in pressure, it is possible to perform stable pressure control, and it is possible to realize a compressor and a control method thereof.

[0075] Sixth Embodiment Next, a sixth embodiment of the present invention will be described.

[0076] In Example 6, in addition to Example 1, the stop pressure P' ＭＡＸ This is an example where there is a lower limit value.

[0077] Fig. 9 is a conceptual diagram showing an operational state flow of the compressor of Example 6. The operational state flow shown in Fig. 9 differs from the operational state flow shown in Fig. 3 in that step 317 is added between steps 308 and 309, step 315 is added between steps 306 and 312, and step 316 is added between steps 315 and 314 in the operational state flow shown in Fig. 3.

[0078] Depending on the equipment that uses the compressed gas, there is a minimum required pressure, so the pressure must be set so as not to fall below that.

[0079] In step 317, the stop pressure P' ＭＡＸ is the lower limit of the stop pressure (P ＭＩＮ Lower limit C of differential pressure from ＬＭＴ (P ＭＩＮ +C ＬＭＴ The stop pressure P' is determined so that it does not fall below the ＭＡＸ If the stop pressure P' is less than the lower limit value, ＭＡＸ Without changing the setting, the process proceeds from step 317 to the next step 305.

[0080] In step 317, the stop pressure P' ＭＡＸ is the lower limit of the stop pressure (P ＭＩＮ Lower limit C of differential pressure from ＬＭＴ ), the process proceeds to step 309.

[0081] Next, step 315 will be described.

[0082] In step 315, the cycle time T ＯＦＦ +T ＯＮ The cycle time T is judged not to be too short. ＯＦＦ +T ＯＮ If the cycle time becomes too short, the frequency of opening and closing of the magnetic switch (electromagnetic contactor) 113 increases, shortening its lifespan. To protect (extend the lifespan of) the magnetic switch (electromagnetic contactor) 113, it is necessary to control the stop pressure so that the cycle time does not become too short.

[0083] Therefore, in step 315, T ＯＦＦ + T ＯＮ is C ＲＳ *T ＥＣＯ If it is smaller, the process proceeds to step 316, and P' ＭＡＸ P ＭＡＸ Set to.

[0084] Other operations are the same as those in the first embodiment.

[0085] In terms of energy-saving performance (effect), the sixth embodiment is less effective than the first embodiment, but has the effect of being able to achieve both user convenience and device reliability.

[0086] (Modification 1) Next, a modification of the sixth embodiment will be described.

[0087] FIG. 10 is a conceptual diagram showing the flow of the operating state of the compressor according to a modified example of the sixth embodiment.

[0088] The difference between the example shown in FIG. 9 and the example shown in FIG. 10 is that steps 315 and 316 shown in FIG. 9 are omitted in FIG.

[0089] In steps 315 and 316, the cycle time T ＯＦＦ +T ＯＮ However, if protection (longer life) of the magnet switch (electromagnetic contactor) 113 is not required, steps 315 and 316 can be omitted.

[0090] Seventh Embodiment Next, a seventh embodiment of the present invention will be described.

[0091] The seventh embodiment is an example in which a heat safety mode is added to the first embodiment.

[0092] Fig. 11 is a conceptual diagram showing the operational flow of the compressor 100 according to the seventh embodiment. In Fig. 11, HS denotes a heat safety, AT denotes an ambient temperature, and PS denotes a pressure switch.

[0093] 11, the process starts at step 401, and the compressor starts operating at step 402. At step 403, it is determined whether the ECO mode is enabled or disabled, and if enabled, the process proceeds to the ECO mode loop at step 413. If the ECO mode is disabled at step 403, the process proceeds to the pressure switch type control loop at step 404.

[0094] In step 405, the compressor 100 is controlled using pressure switch type control (PS mode control). Next, in step 406, it is determined whether the heat safety mode is enabled or disabled, and if enabled, the process proceeds to the determination in step 421. If the heat safety mode is disabled in step 406, the process proceeds to step 407, where it is determined whether or not to issue an ambient temperature abnormality. If an ambient temperature abnormality is not issued in step 407, the process proceeds to step 408, where it is determined whether or not to issue a high ambient temperature alarm. If a high ambient temperature abnormality is not issued in step 408, the process proceeds to step 409, and if the pressure switch type control loop is to be ended, the process ends in step 410. If the compressor is not to be stopped in step 409, the process returns to step 404, and pressure switch type control continues.

[0095] If it is determined in step 407 that the ambient temperature is greater than 45° C., an abnormality flag is set in step 411, the pressure switch type control loop is exited, and the compressor 100 is stopped.

[0096] If it is determined in step 408 that the ambient temperature AT is greater than 40° C., an alarm flag is set in step 412, and pressure switch type control continues while issuing an alarm.

[0097] If the ECO mode is enabled in step 403, the process proceeds to step 413, where an ECO mode control loop is started. In step 414, it is determined whether the heat safety mode is enabled or disabled. If it is enabled, the process proceeds to step 421, where the heat safety mode is entered. If it is disabled, the process proceeds to step 415, where a normal ambient temperature abnormality / warning determination is made.

[0098] In step 415, it is determined whether the ambient temperature AT exceeds 45° C., which is an abnormal temperature. If the temperature is abnormal, an abnormality flag is set in step 417, the ECO mode control loop is exited, and the compressor 100 is stopped.

[0099] If the ambient temperature AT is 45° C. or less in step 415, the process proceeds to step 416, where it is determined whether the ambient temperature AT exceeds 40° C., i.e., an abnormal temperature, and if it exceeds 40° C., an alarm flag is set in step 418. Then, ECO mode control continues while issuing an alarm.

[0100] If the ambient temperature AT is equal to or lower than 40° C. in step 416, the process proceeds to step 419, where the compressor 100 is controlled in the ECO mode control. Then, in step 420, an ECO mode control loop is executed, and if the compressor 100 is not stopped, the process returns to step 413, where the ECO mode control is continued.

[0101] If the heat safety mode is enabled in step 406 or step 414, the process proceeds to step 421, where it is determined whether the ambient temperature AT is greater than 45° C., and if it is greater, the process proceeds to step 422 for AT45 mode control.

[0102] In step 422, the AT45 mode control loop is started, and in step 423, the compressor 100 is controlled in the AT45 mode control.

[0103] If it is determined in step 424 that the ambient temperature AT is lower than 45° C., the AT45 mode control loop is exited and the process proceeds to step 426. If it is not determined in step 424 that the ambient temperature AT is lower than 45° C., the AT45 mode is continued. That is, in step 425, the process returns to step 422 and the AT45 mode control is continued until the AT45 mode control loop is completed.

[0104] In step 426, if the heat safety mode is enabled in step 406 and step 414 and the ambient temperature is determined to be lower than 45° C. and higher than 40° C., the process proceeds to step 427 for AT40 mode control, where the AT40 mode control loop is started. Then, in step 428, the compressor 100 is controlled in the AT40 mode control.

[0105] In step 429, if it is determined that the ambient temperature AT is lower than 40°C, the AT40 mode control loop is exited. If it is not determined that the ambient temperature AT is lower than 40°C in step 429, the process proceeds to step 430. If it is determined that the ambient temperature AT is higher than 45°C in step 430, the process exits the AT40 mode control loop, returns to step 422, and transitions to the AT45 mode control loop. If it is not determined that the ambient temperature AT is higher than 45°C in step 430, the process proceeds to step 431, and the AT40 mode is continued. In step 431, the AT40 mode control loop ends, and the process returns to step 427, and the AT40 mode control is continued.

[0106] If step 426 determines that the ambient temperature AT is not greater than 40° C., step 432 determines whether to return to the ECO mode control loop or the pressure switch type control loop.

[0107] In addition to being able to obtain the same effects as in Example 1, Example 7 is configured to operate the compressor 100 in heat safety mode when the ambient temperature exceeds a certain temperature, and to set an error flag or alarm flag according to the ambient temperature AT and operate the compressor 100 when the heat safety mode is not enabled, thereby realizing a compressor and a control method thereof that are capable of safer and more stable operation.

[0108] The above-described embodiments are merely illustrative examples for aiding in understanding the concept of the present invention, and are not intended to limit the scope of the present invention. Various components may be added, deleted, or converted to the embodiments without departing from the spirit of the present invention.

[0109] The various functional units described in the above embodiments may be realized using circuits, which may be dedicated circuits for realizing specific functions or general-purpose circuits such as processors.

[0110] At least a portion of the processing of each of the above embodiments can be realized by using a general-purpose computer as basic hardware. A program for realizing the above processing may be provided by being stored on a computer-readable recording medium. The program is stored on the recording medium as an installable file or an executable file. Examples of recording media include magnetic disks, optical disks (CD-ROMs, CD-Rs, DVDs, etc.), magneto-optical disks (MOs, etc.), and semiconductor memories. Any recording medium can be used as long as it can store the program and is computer-readable. Furthermore, the program for realizing the above processing may be stored on a computer (server) connected to a network such as the Internet and downloaded to a computer (client) via the network.

[0111] 100, 100A...Compressor, 101...Air, 102...Filter, 103...Compressor body, 104...Motor, 105...Check valve, 106...Aftercooler, 107...Tank, 108...Dryer, 109...Compressed air (compressed gas), 110...Switch, 111, 111A...Control board, 112...Pressure sensor (pressure detector), 113...Magnetic switch, 114...User setting unit, 115...Control unit, 201...Start of operation, 202...Stop pressure (P ＭＡＸ ), 203...changed stop pressure (P' ＭＡＸ ), 204... starting pressure (P ＭＩＮ ), 205...Stop cycle time (T ＯＦＦ ), 206... operation cycle time (T ＯＮ ), 207... cycle time determination formula, 208... ON-OFF time determination formula, 209... pressure change value (P ＥＣＯ ), 210...ECO mode cycle time (T ＥＣＯ) (first cycle threshold), 211...stop pressure stabilization determination formula, 301...flow start step, 302...compressor operation start step, 303...ECO mode control step, 304...cycle time determination step, 305...stop pressure stabilization determination step, 306...ECO flag presence / absence determination step, 307...flow end step, 308...ECO flag setting step, 309...ON-OFF time determination step, 310...changed stop pressure setting step, 311...changed stop pressure setting step, 312... Step for resetting the stop pressure after the change, 313: step for determining the stop pressure, 314: step for deleting the ECO flag, 401: start of operation, 402: compressor control, 403: step for determining the eco mode, 404: step for starting the pressure switch type control loop, 405: pressure switch type control, 406: step for determining the heat safety mode, 407: step for determining an abnormal ambient temperature, 408: step for determining an ambient temperature warning, 409: step for terminating the pressure switch type control loop, 410: end of operation, 411: step for setting an abnormal flag 412: Warning flag setting step, 413: Eco mode control loop start step, 414: Heat safety mode determination step, 415: Ambient temperature abnormality determination step, 416: Ambient temperature warning determination step, 417: Abnormality flag setting step, 418: Warning flag setting step, 419: Eco mode control, 420: Eco mode control loop termination step, 421: AT45 mode determination step, 422: AT45 mode control loop start step, 423: AT45 mode control, 424: AT45 Mode transition determination step, 425...AT45 mode control loop termination step, 426...AT40 mode determination step, 427...AT40 mode control loop start step, 428...AT40 mode control, 429...AT40 mode transition determination step, 430...AT45 mode determination step, 431...AT40 mode control loop termination step, 432...Eco mode control determination step, 1110...pressure control unit, 1111...cycle time determination unit, 1112...stop pressure change unit, 1113...Eco flag setting unit, C ＳＴ...Tolerance, C ＳＴ *T ＥＣＯ ...second cycle threshold, T ＯＦＦ +T ＯＮ ...Pressure increase / decrease cycle

Claims

1. A compressor comprising: an electric motor; a compressor main body driven by the electric motor to generate compressed gas; a tank for storing the compressed gas generated by the compressor main body; a pressure detector for detecting the pressure of the compressed gas in the tank; and a control unit for controlling power supplied to the electric motor in accordance with a detection result of the pressure detector, wherein the control unit determines whether a pressure increase / decrease cycle from when the detection result of the pressure detector reaches a stop pressure, to when the pressure drops to a start pressure, and to when the pressure again reaches the stop pressure, exceeds a first cycle threshold value, and if the pressure increase / decrease cycle exceeds the first cycle threshold value, reduces the stop pressure by a first pressure change value.

2. A compressor according to claim 1, characterized in that the control unit increases the stop pressure by a second pressure change value when the pressure increase / decrease cycle is less than a first cycle threshold value.

3. A compressor as claimed in claim 1, characterized in that the control unit divides the stop pressure into a number of patterns and increases the stop pressure by a predetermined value set for each pattern based on the ratio between the stop cycle time and the operation cycle time of the pressure increase / decrease cycle.

4. The compressor according to claim 1, wherein the control unit also functions as an inverter.

5. A compressor as claimed in claim 2, characterized in that it is provided with a user setting section which enables a user to set the first cycle threshold, the second cycle threshold, the first pressure change value or the second pressure change value, which are parameters, for the control section.

6. A compressor as claimed in claim 1, characterized in that the control unit averages the times of a number of pressure increase / decrease cycles and uses the averaged value to determine whether or not the first cycle threshold is exceeded.

7. A compressor as claimed in claim 1 or 2, characterized in that, when the control unit determines that the stop pressure after being reduced by the first pressure change value will be below a lower limit value of the stop pressure, the control unit does not change the setting of the stop pressure.

8. In the compressor according to claim 2, the control unit controls the pressure increase / decrease cycle (T ＯＦＦ +T ＯＮ ) is within a predetermined tolerance of the first cycle threshold, the stop pressure P ＭＡＸ A compressor characterized in that the settings are not changed.

9. A method for controlling a compressor, the method comprising: storing the compressed gas generated by a compressor main body driven by an electric motor and generating compressed gas in a tank; detecting the pressure of the compressed gas in the tank with a pressure detector; and controlling the power supplied to the electric motor in accordance with the detection result; determining whether or not a pressure increase / decrease cycle from when the detection result of the pressure detector reaches a stop pressure and then drops to a start pressure, until the pressure again reaches the stop pressure, exceeds a first cycle threshold value; and if the pressure increase / decrease cycle exceeds the first cycle threshold value, reducing the stop pressure by a first pressure change value.

10. A method as claimed in claim 9, further comprising increasing said stop pressure by a second pressure change value if said pressure increase / decrease cycle is less than a first cycle threshold.

11. A method for controlling a compressor as claimed in claim 9, characterized in that the stop pressure is divided into a plurality of patterns and increased by a predetermined value set for each pattern based on the ratio between the stop cycle time and the operation cycle time of the pressure increase / decrease cycle.

12. A compressor control method as claimed in claim 10, characterized in that the first cycle threshold, the second cycle threshold, the first pressure change value or the second pressure change value, which are parameters, can be set by a user via a user setting unit.

13. A method for controlling a compressor according to claim 9, further comprising averaging the times of a plurality of pressure increase / decrease cycles to determine whether or not the first cycle threshold value is exceeded.

14. A compressor control method as claimed in claim 9 or 10, characterized in that, when the stop pressure is calculated to be less than a lower limit value of the stop pressure, the setting of the stop pressure is not changed.

15. In the control method for a compressor according to claim 10, the pressure increase / decrease cycle (T ＯＦＦ +T ＯＮ ) is within a predetermined tolerance of the first cycle threshold, the stop pressure P ＭＡＸ The compressor control method according to claim 1, wherein the setting of the compressor is not changed.

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