WO2016147473A1

WO2016147473A1 - Compressor system

Info

Publication number: WO2016147473A1
Application number: PCT/JP2015/081588
Authority: WO
Inventors: 中庭　彰宏
Original assignee: 三菱重工業株式会社
Priority date: 2015-03-18
Filing date: 2015-11-10
Publication date: 2016-09-22
Also published as: DE112015006319T5; US20170298944A1; JP2016173085A

Abstract

A compressor system is provided with a compressor (2) having an impeller (22) that compresses a working fluid by rotating. The compressor (2) has: a housing (23) in which an inflow channel (25) and a discharge channel (27) are formed; a guide vane (251) provided to the inflow channel (25), said guide vane (251) having a changeable angle; a diffuser vane (271) provided to the discharge channel (27), said diffuser vane (271) having a changeable angle; and a control unit (6) that controls the angles of the guide vane (251) and the diffuser vane (271). The control unit (6) controls the angle of at least one of the guide vane (251) and the diffuser vane (271) on the basis of the number of rotations of the impeller (22) and the required PQ characteristic value.

Description

Compressor system

The present invention relates to a compressor system.
This application claims priority on Japanese Patent Application No. 2015-054250 filed on Mar. 18, 2015, the contents of which are incorporated herein by reference.

A compressor system in which a motor and a compressor are integrated includes a compressor that compresses a gas such as air or gas, and a motor that drives the compressor. In the compressor system, a rotating shaft extending from the casing of the compressor and a rotating shaft of a motor extending similarly from the motor casing are connected. The rotation of the motor is transmitted to the compressor. The rotating shafts of the motor and the compressor are stably rotated by being supported by a plurality of bearings.

Such a compressor system is, for example, a subsea production system such as Non-Patent Document 1 (Subsea Production System) or a floating production oil storage facility such as Non-Patent Document 2 (Floating Production Storage and Offloading, FPSO). used. When used in a seabed production system, the compressor system is installed on the seabed. In the compressor system, a production fluid mixed with crude oil, natural gas, etc. is sent to the sea from a production well drilled to a depth of several thousand meters from the sea floor. When used in a floating marine oil storage facility, the compressor system is installed in a marine facility such as a ship.

By the way, in a compressor system used in a submarine production system or a floating offshore oil storage facility, a production fluid mixed with crude oil or natural gas mined from a production well on the seabed flows into the compressor as a fluid. This production fluid may change its characteristics when the content of oil such as crude oil fluctuates during mining. If the characteristics of the inflowing production fluid change, the operable range of the compressor will change. As a result, the operating conditions of the compressor change.

The present invention provides a compressor system that can cope with changing operating conditions.

In order to solve the above problems, the present invention proposes the following means.
A compressor system according to a first aspect of the present invention compresses a working fluid by rotating with a rotor having a rotor that rotates about an axis, a stator that is disposed on an outer peripheral side of the rotor, and the rotor. A compressor having an impeller, wherein the compressor has an inflow channel through which a working fluid flows into the impeller, and a housing in which a discharge channel through which the working fluid pumped by the impeller flows is formed, A guide vane provided in the inflow channel and capable of changing an angle; a diffuser vane provided in the discharge channel and capable of changing an angle; and a control unit configured to control the angles of the guide vane and the diffuser vane. And the control unit includes the guide vane and the front vane based on a required PQ characteristic value which is a value of a required pressure and flow rate and a rotation speed of the impeller. Controlling at least one of the angle of the diffuser vanes.

According to such a configuration, the angle of at least one of the guide vane and the diffuser vane can be controlled based on the required PQ characteristic value and the rotation speed of the impeller. Therefore, at least one of the inflow angle of the working fluid flowing into the impeller from the inflow channel or the inflow angle of the working fluid flowing into the discharge channel from the impeller can be reduced. Thereby, the surge control line can be changed so as to improve the PQ characteristic during operation, and the operating range of the compressor can be expanded.

In the compressor system according to the second aspect of the present invention, in the first aspect, the control unit flows into the impeller from the inflow passage when the rotation speed of the impeller is smaller than a predetermined reference. The angle of the guide vane may be controlled so that the relative angle with respect to the inflow direction of the working fluid becomes small.

According to such a configuration, when the rotation speed of the impeller is smaller than a predetermined reference, the guide vane is guided in the inflow direction of the working fluid flowing into the impeller from the inflow passage on the inflow side of the working fluid into the impeller. Reduce the phase angle. Thereby, the PQ characteristic can be improved efficiently. As a result, by adjusting the angle of the guide vanes, the operating range of the compressor can be efficiently expanded in the low pressure and low flow regions.

In the compressor system according to the third aspect of the present invention, in the first aspect, the control unit flows into the discharge flow path from the impeller when the rotational speed of the impeller is larger than a predetermined reference. You may control the angle of the said diffuser vane so that the relative angle with respect to the inflow direction of the said working fluid may become small.

According to such a configuration, when the rotational speed of the impeller is larger than a predetermined reference, the relative angle of the diffuser vane with respect to the inflow angle of the working fluid flowing into the discharge flow channel on the outflow side of the working fluid from the impeller Make it smaller. Thereby, the PQ characteristic can be improved efficiently. As a result, the operating range of the compressor can be efficiently expanded in the high pressure and high flow areas.

In the compressor system according to the fourth aspect of the present invention, in any one of the first to third aspects, the control unit, when the required PQ characteristic value satisfies a predetermined criterion, The angle of the guide vane may be controlled so that the relative angle with respect to the inflow direction of the working fluid flowing into the impeller from the inflow channel becomes small.

According to such a configuration, the PQ characteristics can be changed only when necessary, and the operating range of the compressor can be efficiently expanded.

In the compressor system according to the fifth aspect of the present invention, in any one of the first to third aspects, the control unit, when the required PQ characteristic value satisfies a predetermined criterion, The angle of the diffuser vane may be controlled so that a relative angle with respect to an inflow direction of the working fluid flowing from the impeller into the discharge flow path becomes small.

According to the compressor system of the present invention, by controlling the angle of at least one of the guide vane and the diffuser vane, the operating range of the compressor can be expanded to cope with changing operating conditions.

It is a mimetic diagram explaining a compressor system in an embodiment of the present invention. It is a schematic diagram which shows the internal structure of the compressor in embodiment of this invention. It is a related figure of the flow and pressure in the compressor in the embodiment of the present invention.

Embodiments according to the present invention will be described below with reference to FIGS. 1 to 3.
The compressor system 1 is used in a subsea production system (Subsea Production System), which is one of the offshore oil and gas field development methods, and is installed on the bottom of the sea, or a floating production storage and offloading, FPSO. ) And used at sea. The compressor system 1 pumps a production fluid such as oil and gas collected from a production well of an oil and gas field existing at several hundred to several thousand m in the seabed as a working fluid.

As shown in FIG. 1, the compressor system 1 includes a compressor 2, a motor 3, a bearing unit 4, a casing 5, and a control unit 6. The compressor 2 includes a shaft 21 that extends in the axis O direction (left and right direction in FIG. 1) as a rotation axis. The motor 3 is directly connected to the shaft 21 and has a rotor 31. The bearing portion 4 supports the shaft 21. The casing 5 accommodates the motor 3 and the compressor 2. The control unit 6 controls the motor 3 and the compressor 2.

The compressor 2 is accommodated in the casing 5. The compressor 2 compresses the working fluid by rotating the shaft 21 around the axis O together with the rotor 31. The compressor 2 of this embodiment includes a shaft 21, an impeller 22, and a housing 23. The shaft 21 extends in the direction of the axis O. The impeller 22 is fixed to the outer peripheral surface of the shaft 21 and rotates with the rotor 31 to compress the working fluid. The housing 23 covers the impeller 22 from the outside.

The shaft 21 is a rotating shaft extending in the direction of the axis O. The shaft 21 is supported by the casing 5 so as to be rotatable around the axis O. The shaft 21 penetrates the housing 23 in the direction of the axis O. The shaft 21 extends from the housing 23 at both ends. The shaft 21 extends in the direction of the axis O in the casing 5 described later.

The impeller 22 rotates with the shaft 21 and compresses the working fluid that passes through the impeller flow path 22a formed therein to generate a compressed fluid. A plurality of impellers 22 are fixed to the outer peripheral surface of the shaft 21 side by side in the direction of the axis O. FIG. 1 shows an example in which a plurality of impellers 22 are provided. However, at least one impeller 22 may be provided in the compressor 2.

The impeller channel 22a circulates the working fluid from the inlet portion of the impeller 22 toward the outlet portion of the impeller 22, as shown in FIG. The inlet portion of the impeller 22 is formed at an end portion facing the upstream side (the right side in FIG. 1 and FIG. 2) which is one side of the impeller 22 in the axis O direction. The exit portion of the impeller 22 is formed at an end portion facing outward in the radial direction with respect to the axis O of the impeller 22.

The housing 23 is an exterior of the compressor 2. The housing 23 accommodates the impeller 22 therein. The housing 23 is accommodated in the casing 5. The housing 23 is provided with a plurality of internal spaces 23a that repeat the contraction and expansion. The impellers 22 are accommodated in the internal spaces 23a. In the internal space 23 a, the impeller 22 is disposed at a predetermined interval with respect to the housing 23. A housing flow path 24 is formed in the housing 23. The housing flow path 24 circulates the working fluid from the impeller 22 arranged on the upstream side in the axis O direction to the impeller 22 adjacent to the downstream side (the left side in FIG. 1 and FIG. 2) that is the other side in the axis O direction.

As shown in FIG. 2, the housing flow path 24 has a suction flow path 25, an intermediate flow path 26, and a discharge flow path (not shown). The suction flow path 25 is disposed on the most upstream side in the direction of the axis O and allows the working fluid to flow into the impeller 22 from the outside. The intermediate flow path 26 is formed between the plurality of impellers 22. The discharge flow path (not shown) discharges the compressed working fluid from the impeller 22 disposed on the most downstream side in the direction of the axis O to the outside.

The suction flow path 25 is formed at a position upstream of the impeller 22 disposed on the most upstream side in the axis O direction. The suction flow path 25 is an inflow flow path that allows the working fluid to flow into the impeller 22 disposed on the most upstream side in the axis O direction. The suction flow path 25 extends radially inward from an opening formed in a part of the circumferential direction on the upstream side in the axis O direction of the housing 23. The suction channel 25 circulates the working fluid toward the inlet of the impeller channel 22a. The suction passage 25 is provided with an inlet guide vane 251 (guide vane). The inlet guide vane 251 turns the working fluid sucked from the outside of the housing 23 in a desired direction and guides it to the impeller flow path 22a.

The angle of the inlet guide vane 251 can be changed by an operating mechanism (not shown). The desired direction in the inlet guide vane 251 is, for example, a direction in which a pre-turn is applied to the working fluid sucked from the outside. The desired direction in the inlet guide vane 251 is, for example, a direction inclined toward the front side in the rotational direction of the impeller 22 as it goes in the radial direction. The inlet guide vane 251 of the present embodiment is adjusted based on a signal from the control unit 6 so that the relative angle with respect to the inflow direction of the working fluid flowing into the impeller flow path 22a becomes small.

The intermediate flow path 26 is formed so as to connect between the impellers 22 adjacent in the axis O direction. The intermediate flow path 26 does not communicate with the outside of the housing 23 but is formed inside the housing 23. The intermediate flow path 26 has a diffuser flow path 27 and a return flow path 28. The diffuser flow path 27 extends outward in the radial direction from the outlet portion of the impeller flow path 22a. The return flow path 28 is connected to the diffuser flow path 27 and extends toward the inlet portion of the impeller flow path 22 a of the adjacent impeller 22.

The diffuser channel 27 has an inlet facing the outlet of the impeller channel 22a. The diffuser flow path 27 allows the working fluid discharged from the impeller flow path 22a to flow outward in the radial direction. The diffuser channel 27 is a discharge channel through which the working fluid pumped by the impeller 22 flows. A diffuser vane 271 is provided in the diffuser flow path 27. The diffuser vane 271 turns the working fluid discharged from the impeller flow path 22a in a desired direction.

The angle of the diffuser vane 271 can be changed by an operating mechanism (not shown). The desired direction in the diffuser vane 271 is a direction in which the dynamic pressure of the circulating working fluid is recovered as a static pressure. The desired direction in the diffuser vane 271 is a direction that inclines forward in the rotational direction of the impeller 22 as it goes in the radial direction. The angle of the diffuser vane 271 of this embodiment is adjusted so that the relative angle with respect to the inflow direction of the working fluid flowing into the diffuser flow path 27 from the impeller flow path 22a is reduced based on a signal from the control unit 6.

The return channel 28 is an inflow channel for allowing the working fluid that has flowed through the diffuser channel 27 to flow into the impeller channel 22a. The return channel 28 has a curved channel 281 and a straight channel 282. The curved channel 281 is connected to the end portion on the outer side in the radial direction of the diffuser channel 27. The straight channel 282 is connected to the end of the curved channel 281.

The curved channel 281 is formed continuously with respect to the outer side in the radial direction of the diffuser channel 27. The curved channel 281 extends so as to bend inward in the radial direction after extending outward in the radial direction. The curved flow path 281 diverts the flow of the working fluid going outward in the radial direction to the flow going inward in the radial direction.

The straight flow path 282 extends from the curved flow path 281 toward the inlet portion of the impeller flow path 22a toward the inside in the radial direction. The straight flow path 282 is formed continuously with respect to the opposite side of the bent flow path 281 connected to the diffuser flow path 27. The straight flow path 282 is provided with a return vane 282a for turning the working fluid flowing through the diffuser flow path 27 in a desired direction.

As shown in FIG. 1, the motor 3 is accommodated in the casing 5 with an interval in the direction of the axis O with respect to the compressor 2. The motor 3 has a rotor 31 and a stator 32. The rotor 31 is fixed so as to be integrated with the shaft 21. The stator 32 is disposed on the outer peripheral side of the rotor 31.

The rotor 31 is integrated with the shaft 21 so as to be rotatable around the axis O. The rotor 31 is directly connected to the outer peripheral side of the shaft 21, which is the outer side in the circumferential direction with respect to the axis O, so as to rotate integrally with the shaft 21 of the compressor 2 without using a gear or the like. Has been. The rotor 31 has, for example, a rotor core (not shown) through which an induced current flows when the stator 32 generates a rotating magnetic field.

The stator 32 is provided with a gap in the circumferential direction so as to cover the rotor 31 from the outer peripheral side. The stator 32 has, for example, a plurality of stator cores (not shown) arranged along the circumferential direction of the rotor 31, and a stator winding (not shown) wound around the stator core. The stator 32 rotates the rotor 31 by generating a rotating magnetic field when an electric current flows from the outside. The stator 32 is fixed in the casing 5.

The bearing part 4 is accommodated in the casing 5, and supports the shaft 21 rotatably. The bearing portion 4 of this embodiment includes a plurality of journal bearings 41 and thrust bearings 42.

The journal bearing 41 supports a load acting on the shaft 21 in the radial direction. The journal bearings 41 are disposed at both ends of the shaft 21 in the axis O direction so as to sandwich the motor 3 and the compressor 2 from the axis O direction. The journal bearing 41 is disposed between the area where the compressor 2 is provided and the area where the motor 3 is provided, and is also arranged closer to the motor 3 than a seal member 51 described later.

The thrust bearing 42 supports a load that acts on the shaft 21 in the direction of the axis O via a thrust collar 21 a formed on the shaft 21. The thrust bearing 42 is disposed between the area where the compressor 2 is provided and the area where the motor 3 is provided, and is disposed closer to the compressor 2 than a seal member 51 described later.

Casing 5 accommodates compressor 2 and motor 3 inside. The casing 5 has a cylindrical shape along the axis O. The inner surface of the casing 5 protrudes toward the shaft 21 between the compressor 2 and the motor 3 in the direction of the axis O. The casing 5 is provided in a protruding portion of a seal member 51 that seals between a region where the compressor 2 is provided and a region where the motor 3 is provided.

The controller 6 controls the compressor 2 and the motor 3 so that the compressor 2 operates under predetermined operating conditions. The control unit 6 controls the angles of the inlet guide vane 251 and the diffuser vane 271. The control unit 6 controls the rotation speed of the rotor 31 of the motor 3. As illustrated in FIG. 2, the control unit 6 includes an input unit 61, a determination unit 62, and an output unit 63. The input unit 61 receives a required PQ characteristic value that is a required pressure and flow rate value and a required rotational speed that is a required rotational speed of the impeller 22. The determination unit 62 determines whether or not the input required PQ characteristic value and the required rotation speed satisfy a predetermined standard. The output unit 63 sends a signal to the motor 3, the inlet guide vane 251, and the diffuser vane 271 based on the determination result in the determination unit 62.

The input unit 61 outputs the input required PQ characteristic value and the required rotation speed to the determination unit 62.
The determination unit 62 determines whether or not the required rotational speed satisfies a predetermined standard, and determines whether or not the required PQ characteristic value is within the initial operation range. The determination unit 62 sends an instruction to the output unit 63 as to how much the angle of the inlet guide vane 251 or the diffuser vane 271 is adjusted based on the determination result.

Here, the initial operation range is a range in which the compressor 2 in the initial setting state can be operated without causing a surge. The initial operating range is a region on the right side of the surge control lines SCL11 and SCL12 and the surge control lines SCL21 and SCL22 in the curve indicating the pressure-flow rate relationship of the compressor 2 shown in FIG. The surge control lines SCL11 and SCL12 are defined by an inlet guide vane 251 and a diffuser vane 271 having an angle determined as an initial value. The surge control lines SCL21 and SCL22 are defined by the inlet guide vane 251 and the diffuser vane 271 after changing the angle described later. A surge occurs in the region on the left side of these surge control lines.

Specifically, the determination unit 62 of the present embodiment determines whether or not the input requested rotational speed is below a predetermined first reference. The determination unit 62 determines whether or not the input requested rotational speed exceeds a predetermined second reference.

Here, the first reference is the rotational speed at which the compressor 2 is operated in a region of lower pressure and lower flow rate than the state where the rotational speed is 100%, assuming that the rotational speed during rated operation is 100%. On the other hand, the second reference is the rotational speed at which the compressor 2 is operated in the region of higher pressure and higher flow rate than the state where the rotational speed is 100%.
In the present embodiment, the first reference is the rotation speed 100%. In the present embodiment, the second reference is the rotation speed 110%.

The determination unit 62 sends an instruction to the output unit 63 to adjust the inlet guide vane 251 when the input requested rotation number is smaller than the first reference rotation number 100%. When the determination unit 62 determines that the required rotational speed is smaller than the first reference, the input required PQ characteristic value is from the low-frequency side surge control line SCL12 in the low-pressure and low-flow region of the initial operation range. Also, it is determined whether or not it is within the right region. Therefore, for example, when the required PQ characteristic value is a value in the region α in FIG. 3, it is determined that the required PQ characteristic value exceeds the low-frequency side surge control line SCL12. In this case, the determination unit 62 sends an instruction to the output unit 63 to adjust the angle of the inlet guide vane 251 so that the relative angle with respect to the inflow direction of the working fluid flowing into the impeller flow channel 22a from the suction flow channel 25 becomes small. .

The determining unit 62 sends an instruction to the output unit 63 to adjust the diffuser vane 271 when the input requested rotational speed is larger than the second reference rotational speed 110%. If the determination unit 62 determines that the required rotational speed is greater than the second reference, the input required PQ characteristic value is higher than the high-frequency side surge control line SCL11 in the high-pressure and high-flow region of the initial operation range. Also, it is determined whether or not it is within the right region. Therefore, for example, when the required PQ characteristic value is a value in the region β in FIG. 3, it is determined that the required PQ characteristic value exceeds the high-frequency side surge control line SCL11. In this case, the determination unit 62 sends an instruction to the output unit 63 to adjust the angle of the diffuser vane 271 so that the relative angle with respect to the inflow direction of the working fluid flowing into the diffuser flow channel 27 from the impeller flow channel 22a becomes small.

The determination unit 62 instructs the output unit 63 not to adjust any angle of the inlet guide vane 251 and the diffuser vane 271 when the input requested rotational speed is larger than the first reference and smaller than the second reference. send. The determination unit 62 sends an instruction to the output unit 63 so as not to adjust any of the inlet guide vane 251 and the diffuser vane 271 even when the input required PQ characteristic value does not exceed the initial operation range.

The output unit 63 sends an instruction to the motor 3 to change the rotation number of the rotor 31 based on the requested rotation number input from the input unit 61 via the determination unit 62. The output unit 63 sends an instruction to the inlet guide vane 251 or the diffuser vane 271 to change the angle based on the determination result in the determination unit 62. Note that the amount of change in the angle of the inlet guide vane 251 or the diffuser vane 271 may be set as appropriate from the difference between the required PQ characteristic value and the current PQ characteristic value.

In this embodiment, in response to an instruction from the output unit 63, the angle of the inlet guide vane 251 is adjusted. As a result, as shown in FIG. 3, the position of the low-frequency side surge control line SCL12 in the low-pressure and low-flow region changes to SCL22. In response to an instruction from the output unit 63, the angle of the diffuser vane 271 is adjusted. As a result, the position of the high-frequency surge control line SCL11 in the high-pressure and high-flow region changes to SCL12.

According to the compressor system 1 as described above, current is supplied to the stator 32 by an external device such as a generator (not shown) based on the required PQ characteristic value and the required rotational speed input to the input unit 61 of the control unit 6. Is done. A rotating magnetic field is generated based on the supplied current, and the rotor 31 of the motor 3 starts rotating together with the shaft 21 at the required rotational speed. By rotating the shaft 21 at a high speed, in the compressor 2, the impeller 22 that rotates together with the shaft 21 compresses the working fluid flowing into the compressor 2 from the upstream side in the axis O direction and compresses from the downstream side in the axis O direction. The compressed fluid that satisfies the required PQ characteristic value is discharged.

Here, for example, when the state quantity such as the oil content in the production fluid fluctuates during the operation of the compressor system 1, the characteristics of the working fluid flowing into the compressor 2 change, and the compressor 2 The discharge pressure changes. Therefore, the required PQ characteristic value and the required rotational speed are input to the input unit 61 of the control unit 6 so as to keep the discharge pressure of the compressor 2 constant. When the requested PQ characteristic value and the requested rotational speed are input, the output unit 63 sends an instruction to the motor 3 to change the rotational speed of the rotor 31 according to the requested rotational speed. As a result, the rotational speed of the impeller 22 is adjusted via the rotor 31. At the same time, if the determination unit 62 determines that the required rotational speed is below the first reference, it determines whether the required PQ characteristic value exceeds the low-frequency side surge control line SCL12. When the required rotational speed is lower than the first reference and the required PQ characteristic value exceeds the low-frequency side surge control line SCL12, the angle of the inlet guide vane 251 is adjusted from the determination unit 62 to the output unit 63. Send a signal. The inlet guide vane 251 that has received the signal from the output unit 63 adjusts the angle so that the relative angle with respect to the inflow direction of the working fluid flowing from the suction flow path 25 into the impeller flow path 22a becomes small. As the angle of the inlet guide vane 251 changes, the position of the low-frequency side surge control line SCL12 changes to SCL22. At the same time, the operating region at the rotation speed of 110% changes from the line L111 to the line L112. Therefore, the PQ characteristics in the low pressure and low flow rate regions can be improved.

When the determination unit 62 determines that the required rotational speed exceeds the second reference, the determination unit 62 determines whether the required PQ characteristic value exceeds the high frequency side surge control line SCL11. When the required rotational speed exceeds the second reference and the required PQ characteristic value exceeds the high frequency side surge control line SCL11, a signal is sent from the determination unit 62 to the output unit 63 to adjust the angle of the diffuser vane 271. Send. The diffuser vane 271 that has received the signal from the output unit 63 adjusts the angle so that the relative angle with respect to the inflow direction of the working fluid flowing into the diffuser flow path 27 from the impeller flow path 22a becomes small. As the angle of the diffuser vane 271 changes, the position of the high frequency side surge control line SCL11 changes to SCL12. At the same time, the operating region at the rotation speed of 110% changes from the line L111 to the line L112. Therefore, the PQ characteristics in the high pressure and high flow rate regions can be improved.

That is, the surge control line can be changed to improve the PQ characteristics during operation. Therefore, even when the state quantity of the working fluid flowing into the impeller flow path 22a changes, the compressor 2 can be operated over a wide range to make the discharge pressure constant. Therefore, the operating range of the compressor 2 can be expanded to cope with changing operating conditions.

When the required rotation speed is low, the impeller 22 rotates at a low rotation speed. Therefore, the compressor 2 is operated in the low pressure and low flow areas. That is, when the required rotational speed is low, the compression efficiency of the working fluid by the impeller 22 is low. Therefore, the volume flow rate of the working fluid flowing through the impeller channel 22a increases. Therefore, when the required rotational speed is low, the inflow direction of the working fluid flowing into the impeller flow path 22a greatly affects the operating range of the compressor 2. Therefore, when the required rotational speed is smaller than a predetermined first reference, the inlet for the inflow direction of the working fluid flowing into the impeller passage 22a from the suction passage 25 on the inflow side of the working fluid into the impeller passage 22a. The phase angle of the guide vane 251 is reduced. Thereby, the PQ characteristic can be improved efficiently. That is, by adjusting the angle of the inlet guide vane 251, the operating range of the compressor 2 can be expanded more efficiently than adjusting the diffuser vane 271 in the low pressure and low flow rate regions.

When the required rotational speed is high, the compressor 2 is operated in a high pressure and high flow rate region. That is, when the required rotational speed is high, the compression efficiency of the working fluid is high. Therefore, the volume flow rate of the working fluid flowing through the impeller flow path 22a is reduced. Therefore, in the region of high pressure and high flow rate, the inflow angle of the working fluid flowing out from the impeller passage 22 a into the diffuser passage 27 greatly affects the operating range of the compressor 2. Accordingly, when the required rotational speed is larger than a predetermined second reference, the relative angle of the diffuser vane 271 with respect to the inflow angle of the working fluid flowing into the diffuser passage 27 on the outflow side of the working fluid from the impeller passage 22a. Is reduced. Thereby, the PQ characteristic can be improved efficiently. That is, by adjusting the angle of the diffuser vane 271, the operating range of the compressor 2 can be expanded more efficiently than adjusting the inlet guide vane 251 in the high pressure and high flow rate regions.

Only when the required PQ characteristic value exceeds the initial operating range, the angles of the inlet guide vane 251 and the diffuser vane 271 are determined. Thereby, it can be changed so as to improve the PQ characteristic only when necessary, and the operating range of the compressor 2 can be efficiently expanded.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the configurations and combinations of the embodiments in the embodiments are examples, and the addition and omission of configurations are within the scope not departing from the gist of the present invention. , Substitutions, and other changes are possible. Further, the present invention is not limited by the embodiments, and is limited only by the scope of the claims.

The guide vane is not limited to the inlet guide vane 251 provided in the suction flow path 25 as in the present embodiment. The guide vane is only required to be provided in the inflow channel and to divert the working fluid flowing into the impeller channel 22a in a desired direction. For example, the guide vane may be a return vane 282 a provided in the straight flow path 282 of the return flow path 28.

In this embodiment, the inlet guide vane 251 and the diffuser vane 271 that are guide vanes are arranged together, but the present invention is not limited to such a configuration. In other words, the compressor 2 may be provided with only the guide vane or only the diffuser vane 271.

The guide vanes and diffuser vanes 271 are not limited to being provided for all the impellers 22 when a plurality of impellers 22 are provided. The guide vane and diffuser vane 271 may be arranged only around the impeller 22 of an arbitrary stage whose operating range is desired to be adjusted.

In the determination unit 62 of the present embodiment, a reference different from the first reference and the second reference is used as a reference for determining whether or not it is within a predetermined operation range. However, the determination is not limited to this. Absent. For example, you may determine whether it is settled in the predetermined driving range using one standard.

According to the above compressor system, by controlling the angle of at least one of the guide vane and the diffuser vane, it is possible to expand the operating range of the compressor and cope with changing operating conditions.

DESCRIPTION OF SYMBOLS 1 Compressor system O Axis 2 Compressor 21 Shaft 22 Impeller 22a Impeller flow path 23 Housing 23a Internal space 24 Housing flow path 25 Suction flow path 251 Inlet guide vane 26 Intermediate flow path 27 Diffuser flow path 271 Diffuser vane 28 Return flow path 281 Curved flow path 282 Straight flow path 282a Return vane 3 Motor 31 Rotor 32 Stator 33 Clearance 4 Bearing portion 41 Journal bearing 42 Thrust bearing 5 Casing 5
51 Sealing member 6 Control unit 61 Input unit 62 Determination unit 63 Output unit

Claims

A motor having a rotor that rotates about an axis, and a stator that is disposed on an outer peripheral side of the rotor;
A compressor having an impeller that compresses the working fluid by rotating together with the rotor,
The compressor is
A housing formed with an inflow channel for allowing working fluid to flow into the impeller, and a discharge channel through which the working fluid pumped by the impeller flows;
A guide vane provided in the inflow channel and capable of changing an angle;
A diffuser vane provided in the discharge channel and capable of changing an angle;
A control unit for controlling the angle of the guide vane and the diffuser vane,
The controller is
A compressor system that controls an angle of at least one of the guide vane and the diffuser vane based on a required PQ characteristic value that is a value of a required pressure and flow rate and a rotation speed of the impeller.
The control unit adjusts the angle of the guide vane so that a relative angle with respect to an inflow direction of the working fluid flowing from the inflow passage into the impeller is small when the rotation speed of the impeller is smaller than a predetermined reference. The compressor system according to claim 1 to be controlled.
The control unit adjusts the angle of the diffuser vane so that a relative angle with respect to an inflow direction of the working fluid flowing from the impeller into the discharge flow path becomes smaller when the rotation speed of the impeller is larger than a predetermined reference. The compressor system according to claim 1 to be controlled.
The controller is configured to reduce an angle of the guide vane so that a relative angle with respect to an inflow direction of the working fluid flowing into the impeller from the inflow passage becomes small when the required PQ characteristic value satisfies a predetermined criterion. The compressor system according to any one of claims 1 to 3, wherein the compressor is controlled.
The controller is configured to reduce an angle of the diffuser vane so that a relative angle with respect to an inflow direction of the working fluid flowing from the impeller into the discharge flow path becomes small when the required PQ characteristic value satisfies a predetermined criterion. The compressor system according to any one of claims 1 to 3, wherein the compressor is controlled.