Compressor and Controlling Method of Volume Ratio Thereof

This application claims the priority benefit of Taiwan application serial no. 113113427, filed on Apr. 10, 2024. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

The disclosure relates to a compressor and a controlling method thereof, and more particularly, to a compressor and a controlling method of a volume ratio thereof.

Common screw compressors have two control valves installed on their hydraulic circuits. By controlling the opening and closing of the two control valves, a slider in the compression chamber can be driven to slide in a forward or reverse direction, thereby adjusting the volume ratio through changes in the position of the slider. Specifically, when the slider slides to a position that satisfies the demand for discharge volume, the volume ratio is fixed. However, the fixed volume ratio does not necessarily match the optimal value under real-time operating conditions, which may result in insufficient compression or over-compression. This leads to excessive energy consumption by the screw compressor, thereby affecting its performance.

The disclosure provides a compressor and a controlling method of a volume ratio thereof, which contribute to improving the performance of the compressor.

A controlling method of a volume ratio of a compressor is provided. The method includes the following steps. An initiation command is received. An adjustment flag is set to a preset flag value. A previous evaluation indicator is recorded. A determination and an adjustment are performed. The determination and the adjustment include the following steps. A preset time is waited for. A current evaluation indicator is recorded. Whether the current evaluation indicator conforms to a preset condition as compared to the previous evaluation indicator is determined. The adjustment flag is maintained as the preset flag value if the current evaluation indicator conforms to the preset condition. The adjustment flag is set to a reverse flag value if the current evaluation indicator does not conform to the preset condition. Whether the adjustment flag is the preset flag value is determined. If so, the adjustment is performed in a same direction as the preset flag value. If not, the adjustment is performed in a reverse direction to the preset flag value. The previous evaluation indicator is updated. The determination and the adjustment are repeatedly performed.

A compressor is also provided. The compressor includes a body, a screw compression group, a volume adjusting group, a driving group, and a control module. The body has an intake end and a discharge end relative to the intake end. The screw compression group is disposed in the body. The volume adjusting group is disposed in the body corresponding to the screw compression group. The driving group is coupled to the volume adjusting group and is used to drive the volume adjusting group to adjust the volume ratio. The control module is electrically connected to the driving group and is used to detect operation statuses of a preceding time sequence and a following time sequence and record the same as corresponding evaluation indicators. Based on a comparison result of the evaluation indicators of the preceding time sequence and the following time sequence, the control module controls the driving group to drive the volume adjusting group to adjust the volume ratio.

Based on the above, the compressor and the controlling method of the volume ratio thereof provided in the disclosure are able to continuously determine the adjustment direction of the volume ratio during the operation of the compressor by comparing evaluation indicators of preceding and following time sequences (such as operating current, consumed power, or performance). The adjustment of the volume ratio is controlled such that the adjusted volume ratio conforms to or approximates the optimal value under real-time operating conditions. Furthermore, during the controlling process of the disclosure, real-time operating conditions can be reflected immediately. The control module controls the volume adjusting group to quickly approach the optimal value for the real-time operating conditions, allowing the compressor's performance to match the best operating conditions. At the same time, the number of detection devices and signals processed by the control module can be reduced, achieving the objectives of simplifying control logic and improving control sensitivity. This significantly reduces the excessive energy consumption of the compressor and greatly enhances the performance of the compressor.

To make the features and advantages of the disclosure more comprehensible, several embodiments accompanied with drawings are described in detail as follows.

is a cross-sectional schematic diagram of a compressor according to an embodiment of the disclosure. Referring to, in this embodiment, a compressormay be a screw compressor with a variable volume ratio and includes a body, a screw compression group, a volume adjusting group, a driving group, and a control module. Specifically, the bodyhas an intake endand a discharge end, wherein the screw compression groupis disposed in a compression chamberof the bodyand located between the intake endand the discharge end. The screw compression groupcompresses a fluid introduced into the compression chamberfrom the intake end. The compressed fluid is then discharged from the compression chamberand finally expelled through the discharge end.

The volume adjusting groupis disposed in the bodycorresponding to the screw compression group. The volume adjusting groupmay include a piston elementand a sliderconnected to the piston element. The piston elementis disposed in a piston chamber of the bodyand is configured to slide reciprocally within the piston chamber. On the other hand, the slideris disposed on one side of the screw compression groupand is configured to slide synchronously with the piston element. When the piston elementdrives the sliderto slide toward the intake endor the discharge end, the position of a radial exhaust port of the sliderchanges, thereby adjusting the volume ratio.

Furthermore, when the piston elementdrives the sliderto slide toward the intake end, the distance between the radial exhaust port of the sliderand the intake endis reduced. This shortens the stroke of the screw compression groupcompressing the fluid, resulting in a decrease in discharge pressure and volume ratio. Conversely, when the piston elementdrives the sliderto slide toward the discharge end, the distance between the radial exhaust port of the sliderand the intake endis increased. This lengthens the stroke of the screw compression groupcompressing the fluid, resulting in an increase in discharge pressure and volume ratio.

As shown in, the driving groupis coupled to the volume adjusting groupand is used to drive the volume adjusting groupto adjust the volume ratio. On the other hand, the control moduleis electrically connected to the driving groupand is used to control the driving groupto drive the volume adjusting groupto adjust the volume ratio. In this embodiment, the driving groupincludes a first oil circuitand a second oil circuitcoupled to the piston element. Both the first oil circuitand the second oil circuitare connected to the piston chamber in which the piston elementis located, and are used respectively for injecting or discharging oil to or from the piston element.

When the control moduleopens the first oil circuitand closes the second oil circuit, the first oil circuitperforms an oil injection operation on the piston element, pushing the piston elementtoward the intake end. Conversely, when the control moduleopens the second oil circuitand closes the first oil circuit, the second oil circuitperforms an oil discharge operation on the piston element, pulling the piston elementtoward the discharge end.

Furthermore, the first oil circuitincludes a first control valveand a first pipelinewherein the first control valveis disposed on the first pipelineand is used to open or block the first pipelineOn the other hand, the second oil circuitincludes a second control valveand a second pipelinewherein the second control valveis disposed on the second pipelineand is used to open or block the second pipeline

As shown in, the control moduleis electrically connected to the first control valveand the second control valveto control the opening or closing of the first control valveand the opening or closing of the second control valveOn the other hand, both the first pipelineand the second pipelineare connected to the piston chamber where the piston elementis located.

When the first control valveis opened, the first pipelineis opened, allowing fluid to flow into the piston chamber via the first pipelineto perform an oil injection operation on the piston element. Conversely, when the first control valveis closed, the first pipelineis blocked, and fluid cannot flow into the piston chamber via the first pipelineOn the other hand, when the second control valveis opened, the second pipelineis opened, allowing fluid to flow out of the piston chamber via the second pipelineto perform an oil discharge operation on the piston element. Conversely, when the second control valveis closed, the second pipelineis blocked, and fluid cannot flow out of the piston chamber via the second pipeline

In this embodiment, the control modulemay include a processor, a storage circuit, and a sensing circuit, wherein the storage circuit and the sensing circuit are electrically coupled to the processor. Specifically, the processor is used to control the overall or partial operation of the compressorand may include, but is not limited to, a central processing unit (CPU), or other programmable general-purpose or special-purpose microprocessors, digital signal processors (DSP), programmable controllers, application specific integrated circuits (ASIC), programmable logic devices (PLD), or other similar devices or combinations thereof.

The storage circuit is used to store data and may include, but is not limited to, volatile storage circuits and non-volatile storage circuits. The volatile storage circuit is used to store data in a volatile manner and may include random access memory (RAM) or similar volatile storage media. The non-volatile storage circuit is used to store data in a non-volatile manner and may include read only memory (ROM), solid-state disks (SSD), and/or traditional hard disk drives (HDD) or similar non-volatile storage media. Additionally, the sensing circuit is used to detect the overall or partial operational status of the compressor, and the processor may store the overall or partial operational status of the compressor, detected by the sensing circuit, in the storage circuit.

is a schematic diagram of the process flow of a controlling method of a volume ratio of a compressor according to an embodiment of the disclosure. Referring toand, the controlling method of the volume ratio of the compressoris described as follows. In steps Sto S, when the compressorstarts operating, the control modulereceives an initiation command and sets the adjustment flag to a preset flag value. On the other hand, the control moduledetects the operational status of the compressoreither immediately upon startup or after a delay of a few seconds, and records this as the previous evaluation indicator. For example, the previous evaluation indicator may include current, power, or performance.

Next, in steps Sand S, after recording the previous evaluation indicator and waiting for a preset time (which may, for example, but not limited to, be any value between 10 and 60 seconds), the control moduledetects the current operational status of the compressorand records this as the current evaluation indicator. For example, the current evaluation indicator may include current, power, or performance. It should be noted that the previous evaluation indicator and the current evaluation indicator correspond to the operational statuses of the compressorat preceding and following time sequences, respectively.

Next, in step S, the control modulecompares the previous evaluation indicator with the current evaluation indicator and determines whether the current evaluation indicator conforms to a preset condition as compared to the previous evaluation indicator. For example, the preset condition may be that the current evaluation indicator is superior to or equal to the previous evaluation indicator, or in other words, that the current evaluation indicator is not inferior to the previous evaluation indicator. On the other hand, the current evaluation indicator being superior to or equal to the previous evaluation indicator may include a current operating current being lower than or equal to a previous operating current, a current consumed power being lower than or equal to a previous consumed power, or a current performance being superior to or equal to a previous performance.

In steps Sto S, if the current evaluation indicator is determined to conform to the preset condition as compared to the previous evaluation indicator, the adjustment flag is maintained as the preset flag value. Conversely, if the current evaluation indicator is determined not to conform to the preset condition as compared to the previous evaluation indicator, the adjustment flag is set to a reverse flag value. Then, regardless of whether the adjustment flag has been switched, a determination is made as to whether the adjustment flag is the preset flag value.

If the adjustment flag remains as the preset flag value, step Sis performed, adjusting in the same direction as the preset flag value. Conversely, if the adjustment flag is not the preset flag value, step Sis performed, adjusting in the reverse direction to the preset flag value. In one example, adjusting in the same direction as the preset flag value may involve controlling the driving groupto drive the volume adjusting groupto increase the volume ratio, which means moving toward the discharge end. Conversely, adjusting in the reverse direction to the preset flag value may involve controlling the driving groupto drive the volume adjusting groupto decrease the volume ratio, which means moving toward the intake end. In another example, adjusting in the same direction as the preset flag value may involve controlling the driving groupto drive the volume adjusting groupto decrease the volume ratio, which means moving toward the intake end. Conversely, adjusting in the reverse direction to the preset flag value may involve controlling the driving groupto drive the volume adjusting groupto increase the volume ratio, which means moving toward the discharge end.

In an example, within the determination and control cycle for adjusting the volume ratio, switching the adjustment flag to the reverse flag value may be configured as follows: during a cycle of continuously increasing the volume ratio, if the current evaluation indicator is determined not to conform to the preset condition as compared to the previous evaluation indicator, the operation of increasing the volume ratio is stopped, and the operation of decreasing the volume ratio is performed instead. At this time, the adjustment flag is switched, for example, set to the reverse flag value instead of the preset flag value. Conversely, during a cycle of continuously decreasing the volume ratio, if the current evaluation indicator is determined not to conform to the preset condition as compared to the previous evaluation indicator, the operation of decreasing the volume ratio is stopped, and the operation of increasing the volume ratio is performed instead. At this time, the adjustment flag is switched, for example, reverted to the preset flag value.

In another example, within the determination and control cycle for adjusting the volume ratio, switching the adjustment flag to the reverse flag value may be configured as follows: during a cycle of continuously decreasing the volume ratio, if the current evaluation indicator is determined not to conform to the preset condition as compared to the previous evaluation indicator, the operation of decreasing the volume ratio is stopped, and the operation of increasing the volume ratio is performed instead. At this time, the adjustment flag is switched, for example, set to the reverse flag value instead of the preset flag value. Conversely, during a cycle of continuously increasing the volume ratio, if the current evaluation indicator is determined not to conform to the preset condition as compared to the previous evaluation indicator, the operation of increasing the volume ratio is stopped, and the operation of decreasing the volume ratio is performed instead. At this time, the adjustment flag is switched, for example, reverted to the preset flag value.

In other words, the control modulecan control the direction of increase or decrease of the volume ratio based on the switching of the flag value. If increasing the volume ratio is considered as an operation in the same direction, then decreasing the volume ratio is considered as an operation in the reverse direction. Conversely, if decreasing the volume ratio is considered as an operation in the same direction, then increasing the volume ratio is considered as an operation in the reverse direction.

In one example, the preset flag value may be set to 1. During a cycle of continuously increasing the volume ratio, the adjustment flag remains unchanged. If the determination result of the current evaluation indicator compared to the previous evaluation indicator does not conform to the preset condition, the adjustment flag is switched. For instance, the adjustment flag may be set to 0, and this step is regarded as setting the adjustment flag to the reverse flag value.

Further to the above, when the adjustment flag is set to 0, an operation to decrease the volume ratio is performed. If the determination result of the current evaluation indicator compared to the previous evaluation indicator conforms to the preset condition, the adjustment flag remains unchanged, and the operation to decrease the volume ratio continues. Conversely, if the determination result of the current evaluation indicator compared to the previous evaluation indicator does not conform to the preset condition, the adjustment flag is switched. For instance, the adjustment flag may be set to 1 (i.e., reverted to the preset flag value), and this step is regarded as setting the adjustment flag to the reverse flag value.

In another example, the preset flag value may be set to 1. During a cycle of continuously decreasing the volume ratio, the adjustment flag remains unchanged. If the determination result of the current evaluation indicator compared to the previous evaluation indicator does not conform to the preset condition, the adjustment flag is switched. For instance, the adjustment flag may be set to 0, and this step is regarded as setting the adjustment flag to the reverse flag value.

Further to the above, when the adjustment flag is set to 0, an operation to increase the volume ratio is performed. If the determination result of the current evaluation indicator compared to the previous evaluation indicator conforms to the preset condition, the adjustment flag remains unchanged, and the operation to increase the volume ratio continues. Conversely, if the determination result of the current evaluation indicator compared to the previous evaluation indicator does not conform to the preset condition, the adjustment flag is switched. For instance, the adjustment flag may be set to 1 (i.e., reverted to the preset flag value), and this step is regarded as setting the adjustment flag to the reverse flag value.

In other words, if the current adjustment flag is set to 1, then in the step of setting the adjustment flag to the reverse flag value, the adjustment flag is changed to 0. Conversely, if the current adjustment flag is set to 0, then in the step of setting the adjustment flag to the reverse flag value, the adjustment flag is changed to 1. It is worth mentioning that in practical applications, based on the operational requirements of different compressors, the operation of increasing or decreasing the volume ratio may be set as the preset flag value 1. Therefore, for compressors with different configuration requirements, the direction of the adjustment flag when the preset flag value is 1 may vary.

Then, in step S, the previous evaluation indicator is updated, and the determination and adjustment steps, including steps S, S, S, S, S, S, and S, are repeatedly executed. Specifically, updating the previous evaluation indicator involves the control modulereplacing the previous evaluation indicator with the current evaluation indicator, which serves as the comparison benchmark for the next determination and adjustment steps. Additionally, once the compressoris shut down, the control modulereceives a shutdown command and stops all actions such as detection, recording, determination, adjustment, and control.

The controlling method of the volume ratio of the compressordescribed above enables the continuous determination of the direction of increase or decrease of the volume ratio during the operation of the compressorby comparing evaluation indicators of preceding and following time sequences, such as operating current, consumed power, or performance. The adjustment of the volume ratio is controlled so that the adjusted volume ratio conforms to or approximates the optimal value under real-time operating conditions. Furthermore, during the control process of the disclosure, the real-time operating conditions can be immediately reflected. The control module can control the volume adjusting group to quickly approach the optimal value for the real-time operating conditions, allowing the performance of the compressor to match the best operating conditions. Simultaneously, the number of detection devices and the number of signals processed by the control module can be reduced, achieving the goals of simplifying control logic and improving control sensitivity. This significantly mitigates the issue of excessive energy consumption of the compressorand greatly enhances its performance.

is a cross-sectional schematic diagram of another embodiment of the compressor according to the disclosure. Referring to, a compressorA in this embodiment can also execute the controlling method of the volume ratio of the compressorin the previous embodiment. The compressorA in this embodiment is generally similar to the compressorin the previous embodiment, with the main difference lying in the design of the driving group and the volume adjusting group.

Specifically, in this embodiment, a volume adjusting groupmay include a screwand a slidercoupled to the screw. The rotation of the screwcan drive the sliderto slide toward the intake endor the discharge end, thereby changing the position of the radial exhaust port of the sliderand achieving the purpose of adjusting the volume ratio.

On the other hand, the driving group includes a motorwhich can be a servo motor or a stepper motor. The screwis coupled to the output shaft of the motorallowing the screwto rotate synchronously in the same direction as the output shaft of the motorWhen the control modulecontrols the motorto drive the screwto rotate in a first rotational direction R, the screwdrives the sliderto slide toward the intake end. This shortens the distance between the radial exhaust port of the sliderand the intake end, reduces the stroke of the screw compression groupcompressing the fluid, and lowers the discharge pressure and volume ratio. Conversely, when the control modulecontrols the motorto drive the screwto rotate in a second rotational direction Ropposite to the first rotational direction R, the screwdrives the sliderto slide toward the discharge end. This increases the distance between the radial exhaust port of the sliderand the intake end, lengthens the stroke of the screw compression groupcompressing the fluid, and increases the discharge pressure and volume ratio.

is a schematic diagram of the process flow of a controlling method of a volume ratio of a compressor according to another embodiment of the disclosure. Referring to, the volume ratio controlling method in this embodiment can be implemented in the compressorshown inor the compressor shown in. The volume ratio controlling method in this embodiment is generally similar to the method in the previous embodiment, with the main difference lying in the accumulation and determination of the same-direction adjustment count (i.e., the count of continuously increasing or continuously decreasing the volume ratio).

In this embodiment, when the adjustment flag is preset to the preset flag value, if the determination result of the evaluation indicators in preceding and following time sequences in each cycle (i.e., the determination result of the current evaluation indicator compared to the previous evaluation indicator) conforms to the preset condition, the same-direction adjustment count is updated by adding one to the count. The current flag value is maintained to perform an adjustment operation in the same direction as the preset flag value, as shown in steps S, S, S, S, and S.

Furthermore, in step S, although the determination result of the evaluation indicators in preceding and following time sequences in each cycle conforms to the preset condition, it is necessary to determine whether the accumulated same-direction adjustment count is less than a preset count. If the accumulated same-direction adjustment count is less than the preset count, the same-direction adjustment count is updated (as in step S), and the current flag value is maintained to perform the same-direction adjustment operation (as in steps Sand S).

Conversely, as shown in steps Sand S, if the accumulated same-direction adjustment count is equal to or greater than the preset count, the adjustment flag is forcibly set to the reverse flag value, and the same-direction adjustment count is reset to zero. On the other hand, as shown in steps Sand S, if the determination result of the evaluation indicators in preceding and following time sequences in any cycle does not conform to the preset condition, the adjustment flag is forcibly set to the reverse flag value, and the same-direction adjustment count is reset to zero. In practical applications, the preset count can be set to any value between 5 and 30 based on the model specifications of different compressors, but it is not limited to this range.

As shown in steps S, S, and S, after the adjustment flag is set to the reverse flag value, an adjustment operation in the reverse direction to the preset flag value is performed. Subsequently, as shown in steps S, S, S, and S, the determination of the evaluation indicators in preceding and following time sequences for the next cycle is performed. If the determination result of the evaluation indicators in preceding and following time sequences in each cycle conforms to the preset condition, the same-direction adjustment count is updated by adding one to the count. The current flag value is maintained to perform the same-direction adjustment operation, such as continuously performing an adjustment operation in the reverse direction to the preset flag value, as shown in steps S, S, S, S, and S.

Furthermore, in step S, although the determination result of the evaluation indicators in preceding and following time sequences in each cycle conforms to the preset condition, it is necessary to determine whether the accumulated same-direction adjustment count is less than the preset count. If the accumulated same-direction adjustment count is less than the preset count, the same-direction adjustment count is updated (as in step S), and the current flag value is maintained to perform the same-direction adjustment operation (as in steps Sand S).

Conversely, as shown in steps Sand S, if the accumulated same-direction adjustment count is equal to or greater than the preset count, the adjustment flag is forcibly set to the reverse flag value (i.e., reverted to the preset flag value), and the same-direction adjustment count is reset to zero. On the other hand, as shown in steps Sand S, if the determination result of the evaluation indicators in preceding and following time sequences in any cycle (i.e., the determination result of the current evaluation indicator compared to the previous evaluation indicator) does not conform to the preset condition, the adjustment flag is forcibly set to the reverse flag value (i.e., reverted to the preset flag value), and the same-direction adjustment count is reset to zero. As shown in steps S, S, and S, after the adjustment flag is reverted to the preset flag value, an adjustment operation in the same direction as the preset flag value is performed.

Through the above determination and control cycle for adjusting the volume ratio, the optimal range of the volume ratio can be continuously narrowed, approaching the optimal volume ratio under real-time operating conditions. Additionally, it prevents the volume ratio from increasing or decreasing without limit, thereby avoiding exceeding the hardware device's limit settings.

On the other hand, as shown in steps Sand S, if the compressoris restarted after being shut down, the control modulewill first perform an initialization operation, such as setting the adjustment flag to the preset flag value and resetting the same-direction adjustment count to zero.

The compressor and the control method provided in the disclosure are not only applicable to the volume ratio control of fixed-frequency compressors but also to variable-frequency compressors. Furthermore, when the frequency of a variable-frequency compressor stabilizes after a period of change, the control method of the disclosure can execute volume ratio control during the stable frequency state of the variable-frequency compressor. Regardless of how the frequency of the variable-frequency compressor changes, the control process of the disclosure can immediately reflect the real-time operating conditions. The control module can control the volume adjusting group to quickly approach the optimal value for the real-time operating conditions, ensuring that the compressor's performance meets the optimal operating conditions.

In summary, the compressor and the controlling method of a volume ratio thereof provided in the disclosure can continuously determine the direction of increase or decrease of the volume ratio during the operation of the compressor by comparing evaluation indicators of preceding and following time sequences, such as operating current, consumed power, or performance. The adjustment of the volume ratio is controlled such that the adjusted volume ratio conforms to or approximates the optimal value under real-time operating conditions. Furthermore, during the control process of the disclosure, the real-time operating conditions can be immediately reflected. The control module can control the volume adjusting group to quickly approach the optimal value for the real-time operating conditions, ensuring that the compressor's performance meets the optimal operating conditions. At the same time, the number of detection devices and the number of signals processed by the control module can be reduced, achieving the objectives of simplifying control logic and improving control sensitivity. This significantly mitigates the issue of excessive energy consumption of the compressor and greatly enhances its performance.

Although the disclosure has been described with reference to the above embodiments, they are not intended to limit the disclosure. It will be apparent to one of ordinary skill in the art that modifications to the described embodiments may be made without departing from the spirit and the scope of the disclosure. Accordingly, the scope of the disclosure will be defined by the attached claims and their equivalents and not by the above detailed descriptions.