System comprising rotary electric machine

Abstract

To suppress continuation of short circuit due to induction voltage by a simple configuration.SOLUTION: A rotor shaft 40 extends in an axial direction. A rotary electric machine 30 comprises: a rotor 34 provided radially outside the rotor shaft 40; and a stator 38 provided radially outside the rotor 34. Rolling bearings 42, 44 are interposed between the rotor shaft 40 and the rotor 34 to allow relative rotation of the rotor shaft 40 and the rotor 34. A lock magnet 60 is fixed to the rotor shaft 40. A lock pin 50 switches coupling and uncoupling between the rotor 34 and the lock magnet 60 by moving in an axial direction by excitation of the lock magnet 60.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a system including a rotating electric machine. [Background technology]

[0002] JP 2013-193503 A (Patent Document 1) discloses a marine propulsion system. The marine propulsion system includes an electric motor as an auxiliary propulsion device that assists the driving of a main propulsion unit by a diesel engine in accordance with electric power generated by a generator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-193503 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above document discloses a configuration in which an electric motor is disposed coaxially with the drive shaft of the main propulsion unit and is directly connected to the drive shaft. When a permanent magnet motor is used as the electric motor, when the propeller receives the force of the ocean current and the drive shaft rotates, a voltage is generated in the stator winding of the electric motor due to the effect of the induced voltage of the permanent magnet. When a phase-to-phase short circuit or turn-to-turn short circuit occurs in the winding of the electric motor, the induced voltage may continue the phase-to-phase short circuit or turn-to-turn short circuit, and the short circuit current may continue, leading to the expansion of damage.

[0005] The present disclosure proposes a system including a rotating electric machine that can suppress the continuation of a short circuit caused by an induced voltage with a simple configuration and prevent damage from spreading. [Means for solving the problem]

[0006] According to the present disclosure, a system including a rotating electric machine is proposed. The rotor shaft extends in the axial direction. The rotating electric machine has a rotor provided radially outward of the rotor shaft, and a stator provided radially outward of the rotor. The bearing is interposed between the rotor shaft and the rotor to enable relative rotation between the rotor shaft and the rotor. The locking electromagnet is fixed to the rotor shaft. The locking member moves axially when the locking electromagnet is excited, thereby switching between connection and disconnection between the rotor and the locking electromagnet. Effect of the Invention

[0007] According to the system of the present disclosure, it is possible to suppress the continuation of a short circuit caused by an induced voltage with a simple configuration, and to prevent the damage from spreading. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a general configuration of a marine electric propulsion system including an electric motor; [Diagram 2] FIG. 1 is a schematic diagram showing a general configuration of a system in which a generator supplies electric power to a ship. [Diagram 3] 1 is a schematic diagram showing a configuration of a system including a rotating electric machine according to an embodiment; [Figure 4] FIG. 4 is a cross-sectional view of the rotating electric machine shown in FIG. [Diagram 5] FIG. 2 is a diagram showing an example of an excitation circuit that excites a locking electromagnet. [Figure 6] FIG. 13 is a diagram showing the arrangement of the lock pin when the locking electromagnet is not energized. [Figure 7] FIG. 13 is a diagram showing the arrangement of the lock pins when the locking electromagnet is excited. [Figure 8] 1 is an example of a circuit diagram of an inverter system. [Figure 9] FIG. 2 is a functional block diagram of a monitoring control device. [Figure 10] FIG. 13 is a diagram showing a modified example of an excitation circuit for a locking electromagnet. [Figure 11] 4 is a flowchart showing an operation of a system including a rotating electric machine according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. It is also intended from the beginning that any configuration may be extracted from the embodiments and that they may be combined in any desired manner.

[0010] 1 is a schematic diagram showing the general configuration of a ship electric propulsion system equipped with an electric motor. A power source 1, an inverter system 10, and a rotating electric machine 30 are mounted on a ship 100. The power source 1 is, for example, a DC power source. The rotating electric machine 30 functions as an electric motor. The rotating electric machine 30 is a permanent magnet type rotating electric machine that uses a permanent magnet in the rotor. In this ship electric propulsion system, the rotating electric machine 30 (electric motor) is driven by the power source 1 and the inverter system 10, and the driving force is transmitted to a propeller 110 via a propeller shaft 111, driving the propeller 110 to propel the ship 100.

[0011] 2 is a schematic diagram showing a schematic configuration of a system in which a generator supplies electric power to a ship. An engine 120 is mounted on a ship 100. The engine 120 is, for example, a diesel engine. An output shaft of the engine 120 is directly connected to a propeller shaft 111. A rotating electric machine 30 is inserted in the same propeller shaft 111. The rotating electric machine 30 can be caused to function as an electric motor and used to generate propulsive force that assists the engine 120 and moves the propeller 110. Alternatively, the rotating electric machine 30 can be caused to function as a generator and generate electric power using part of the driving force generated by the engine 120 as motive power, and the inverter system 10 can be caused to perform regenerative operation (converter operation) and the generated electric power can be supplied to the power source 1 side.

[0012] 1 and 2 disclose a two-shaft propulsion vessel 100 equipped with two sets of propellers 110 and propeller shafts 111. The vessel 100 may be a single-shaft propulsion vessel equipped with only one set of propellers 110 and propeller shafts 111. The vessel 100 may be a multi-shaft propulsion vessel equipped with three or more sets of propellers 110 and propeller shafts 111.

[0013] 3 is a schematic diagram showing the configuration of a system including a rotating electric machine 30 according to an embodiment. A housing 31 is formed in a box shape. The rotating electric machine 30 is accommodated in the housing 31. The rotating electric machine 30 has a rotor 34 and a stator 38.

[0014] The stator 38 has a stator core fixed to the housing 31, and a stator winding 381 (not shown in FIG. 3 but shown in FIG. 8) wound around the stator core and fixed to the stator core. The stator 38 receives electric power from the inverter system 10 and generates a force that rotates the rotor 34. The stator 38 is formed in a hollow cylindrical shape surrounding the rotor 34.

[0015] The rotor 34 is disposed inside the stator 38. The rotor 34 is a permanent magnet rotor. The rotor 34 has a hollow cylindrical shape. The outer peripheral surface of the rotor 34 and the inner peripheral surface of the stator 38 face each other.

[0016] The rotor 34 is fitted into the rotor shaft 40 via two rolling bearings 42, 44. The rotor shaft 40 passes through the housing 31. The rotor shaft 40 has a solid cylindrical shape. One end of the rotor shaft 40 (the left end in FIG. 3) is connected to a propeller shaft 111. The rotor shaft 40 and the propeller shaft 111 are configured to be rotatable together.

[0017] In the following description, the axial direction of rotation of rotor shaft 40 (left-right direction in FIG. 3) is referred to as the "axial direction." The radial direction about the center of rotation of rotor shaft 40 is referred to as the "radial direction." The up-down direction in FIG. 3 is an example of the radial direction. Rotor shaft 40 extends in the axial direction. Rotor 34 is provided radially outward from rotor shaft 40. Stator 38 is provided radially outward from rotor 34. Stator 38 is disposed farther away from rotor shaft 40 than rotor 34.

[0018] The two rolling bearings 42, 44 are arranged side by side in the axial direction. The inner rings of the rolling bearings 42, 44 are fixed to the outer surface of the rotor shaft 40. The outer rings of the rolling bearings 42, 44 are fixed to the inner surface of the rotor 34. The rolling bearings 42, 44 have rolling elements between the inner and outer rings. The rolling elements may be balls or rollers. The rolling bearings 42, 44 are interposed between the rotor shaft 40 and the rotor 34 in the radial direction.

[0019] The excitation winding 90 includes a rotating side winding 76 and a fixed side winding 86. The locking electromagnet 60, the rotary rectifier 74, and the rotating side winding 76 are attached to the rotor shaft 40. The locking electromagnet 60, the rotary rectifier 74, and the rotating side winding 76 are fixed to the rotor shaft 40 so as to be rotatable together with the rotor shaft 40. The locking electromagnet 60, the rotary rectifier 74, and the rotating side winding 76 may be directly attached to the rotor shaft 40, or may be attached to a steel material or an iron core material fitted to the rotor shaft 40. The locking electromagnet 60, the rotary rectifier 74, and the rotating side winding 76 are connected by a connection cable 78 to form an electric circuit. The rotating side winding 76 is arranged so that it receives power from the fixed side winding 86 by electromagnetic induction. The rotating side winding 76 and the fixed side winding 86 may each be wound around an iron core and fixed so as to facilitate electromagnetic induction. The rotating winding 76 is an example of a secondary winding, and the fixed winding 86 is an example of a primary winding.

[0020] A lock pin 50 is embedded in the locking electromagnet 60. Fig. 4 is a cross-sectional view of the rotating electric machine 30 shown in Fig. 3. Fig. 4 shows a cross section taken along the broken line IV-IV shown in Fig. 3. The locking electromagnet 60 is fitted into the rotor shaft 40, and the rotor 34 is fitted into the rotor shaft 40 via rolling bearings 42, 44.

[0021] In the figure, four locking electromagnets 60 are fixed on the circumference of the rotor shaft 40, but the number of locking electromagnets 60 is not limited as long as there is one or more. When multiple locking electromagnets 60 are provided, it is preferable that they are arranged at equal intervals around the circumference of the rotor shaft 40 so that the center of gravity is at the center of the rotor shaft 40, as shown in Figure 4. When an even number of locking electromagnets 60 are provided, it is preferable that two locking electromagnets 60 are arranged so that they extend on the same straight line with the rotor shaft 40 in between, as shown in Figure 4.

[0022] 5 is a diagram showing an example of an excitation circuit 70 that excites the locking electromagnet 60. As shown in FIG. 5, the excitation circuit 70 of the locking electromagnet 60 is divided into a rotation side circuit 71 and a fixed side circuit 81.

[0023] The rotating side circuit 71 is attached to the rotor shaft 40. The rotating side circuit 71 includes an electromagnetic coil 72, a rotating rectifier 74, and a rotating side winding 76. The electromagnetic coil 72, the rotating rectifier 74, and the rotating side winding 76 are connected by a connection cable 78.

[0024] The fixed-side circuit 81 includes an excitation power supply 82, a switch 84, and a fixed-side winding 86. The excitation power supply 82, the switch 84, and the fixed-side winding 86 are connected by a connection cable 88. The rotating-side winding 76 and the fixed-side winding 86 constitute an excitation winding 90 also shown in FIG.

[0025] When exciting the electromagnet coil 72 of the locking electromagnet 60, the electromagnet coil 72 of the locking electromagnet 60 is excited with DC from an excitation power source 82 via an excitation winding 90 and a rotary rectifier 74. The connection to the excitation power source 82 is turned on or off by a switch 84. This switch 84 may be operated manually or remotely using a contactor, semiconductor switch, or the like.

[0026] When the switch 84 is turned on, a direct current flows through the fixed circuit 81. A direct current flows through the fixed winding 86. When the rotor shaft 40 rotates in this state, an alternating magnetic flux is generated in the rotating winding 76, generating an alternating electromotive force. This alternating electromotive force is full-wave rectified by the rotary rectifier 74 to become a direct current. The locking electromagnet 60 is excited by the direct current rectified by the rotary rectifier 74. In other words, the power of the fixed circuit 81 is configured to be transmitted to the rotating circuit 71 in a non-contact manner. A magnetic force is generated by passing a direct current through the electromagnet coil 72 of the locking electromagnet 60, and the lock pin 50 is operated. The lock pin 50 includes a magnetic body in at least a part thereof so that it can be operated by the magnetic flux generated by the electromagnet coil 72.

[0027] 6 is a diagram showing the arrangement of the lock pin 50 when the locking electromagnet 60 is not excited. An end face 35 of the rotor 34 is formed with a bottomed recess 36 that is a recess in part of the end face 35. The locking electromagnet 60 has an opposing surface 65 that faces the rotor 34. An opposing surface 65 is formed with a bottomed recess 66 that is a recess in part of the opposing surface 65. The lock pin 50 has a tip surface 51 that is one end face, and a base end surface 52 that is the end face opposite to the tip surface 51.

[0028] A spring 54 is provided between a bottom surface 67 of the recess 66 and the base end surface 52 of the lock pin 50. One end of the spring 54 is attached to the bottom surface 67, and the other end of the spring 54 is attached to the base end surface 52. The spring 54 biases the lock pin 50 in a direction in which the lock pin 50 protrudes out of the recess 66 (to the right in FIG. 6).

[0029] 6, when the locking electromagnet 60 is not excited, the biasing force of the spring 54 acts on the lock pin 50. At this time, a portion of the lock pin 50, including the tip surface 51, is disposed within the recess 36 of the rotor 34. A portion of the lock pin 50, including the base end surface 52, is disposed within the recess 66 of the locking electromagnet 60. In this state, the locking electromagnet 60 is mechanically fixed to the rotor 34 via the lock pin 50. The lock pin 50 connects the rotor 34 and the rotor shaft 40.

[0030] When the rotor 34 rotates due to the rotational driving force generated by the stator 38 in a state in which the locking electromagnet 60 shown in Fig. 6 is not excited, the rotation of the rotor 34 is transmitted to the rotor shaft 40 via the lock pin 50 and the locking electromagnet 60. As a result, the rotor shaft 40 rotates integrally with the rotor 34. Since the rotor shaft 40 is connected to the propeller shaft 111, the propeller shaft 111 rotates, and the propeller 110 rotates. In this manner, the ship 100 is propelled.

[0031] The number of locking electromagnets 60 and lock pins 50 may be determined by the upper limit of the force acting on the lock pin 50 when transmitting the rotation of the rotor 34 to the rotor shaft 40. If there are multiple locking electromagnets 60 and lock pins 50, the force acting on the lock pin 50 when transmitting the rotation of the rotor 34 to the rotor shaft 40 is dispersed. The number of locking electromagnets 60 and lock pins 50 can be selected so that the force acting on the lock pin 50 is within the mechanical strength of the lock pin 50.

[0032] 7 is a diagram showing the arrangement of the lock pin 50 when the locking electromagnet 60 is excited. By passing a direct current through the electromagnetic coil 72 to excite the locking electromagnet 60, the lock pin 50 operates to be drawn into the recess 66. The lock pin 50 moves in the axial direction due to the excitation of the locking electromagnet 60. Specifically, the lock pin 50 moves to the left in FIGS. 6 and 7.

[0033] The action of the locking electromagnet 60 causes the lock pin 50 to be stored inside the locking electromagnet 60. The rotor 34 and the rotor shaft 40 are electrically and mechanically separated. The lock pin 50 moves in the axial direction, switching the rotor 34 and the locking electromagnet 60 to a disconnected state. The lock pin 50 corresponds to an example of a "locking member" that switches between a connection and a disconnection between the rotor 34 and the rotor shaft 40.

[0034] The spring 54 corresponds to an example of a "biasing member" that biases the lock pin 50 in a direction opposite to the moving direction caused by excitation of the locking electromagnet 60. The biasing member is not limited to the spring 54, and may be, for example, rubber.

[0035] When the locking pin 50 is released by excitation of the locking electromagnet 60, the rotor 34 is no longer mechanically fixed to the rotor shaft 40. Because the rotor 34 is connected to the rotor shaft 40 by the rolling bearings 42, 44, the rotor 34 and the rotor shaft 40 are allowed to rotate relative to each other. In this state, the rotor 34 is no longer linked to the rotation of the rotor shaft 40. In other words, even if the rotor shaft 40 rotates, the rotor 34 does not rotate.

[0036] In the marine vessel electric propulsion system shown in Fig. 1, when the propeller 110 is subjected to a force due to an ocean current, the propeller shaft 111 rotates (freewheels), and even if the rotor shaft 40 rotates integrally with the propeller shaft 111, the rotor 34 does not rotate because the rotor 34 and the rotor shaft 40 are not mechanically fixed to each other. Therefore, by turning on the switch 84 when a short circuit in the rotating electric machine 30 is detected, an induced voltage due to a permanent magnet is no longer generated in the stator winding 381. Therefore, when a short circuit occurs between phases or turns in the stator winding 381 of the rotating electric machine 30, the short circuit does not continue due to the induced voltage, and the short circuit current does not continue. Therefore, the marine vessel electric propulsion system of the embodiment can suppress the expansion of damage to the rotating electric machine 30.

[0037] 2, if a fault such as a short circuit occurs between the rotating electric machine 30 and the inverter system 10 for some reason, it is necessary to stop the rotation of the rotor 34 so that the short circuit does not continue. However, if the engine 120 is stopped, the propulsive force of the boat 100 will be lost, so the engine 120 must continue to operate. By separating the rotor 34 from the rotor shaft 40, it is possible to stop the rotation of the rotor 34 even if the engine 120 is operating. In other words, it is possible to stop the rotation of the rotor 34 while driving the engine 120 and maintaining the propulsive force of the boat 100.

[0038] Fig. 8 is an example of a circuit diagram of the inverter system 10. Fig. 9 is a functional block diagram of the monitoring control device 20. As shown in Fig. 8, the inverter system 10 has, for example, three single-phase inverters, a U-phase inverter 11U, a V-phase inverter 11V, and a W-phase inverter 11W, and a monitoring control device 20. Note that in the example of Fig. 8, the inverter system 10 combines three single-phase inverters to produce a three-phase output, and the rotating electric machine 30 has a three-phase input, but the inverter system 10 may have a multi-phase output of three or more phases (for example, 12 phases), and the rotating electric machine 30 may also have a multi-phase input (for example, 12 phases).

[0039] As shown in FIG. 9, the monitoring and control device 20 includes a single-phase inverter control unit 21 and a short circuit monitoring unit 22.

[0040] DC power is supplied from the power source 1 to the DC sides of the U-phase inverter 11U, the V-phase inverter 11V, and the W-phase inverter 11W. The U-phase inverter 11U, the V-phase inverter 11V, and the W-phase inverter 11W each have a switching element. The switching element is, for example, an insulated gate bipolar transistor (IGBT). The single-phase inverter control unit 21 controls each of the U-phase inverter 11U, the V-phase inverter 11V, and the W-phase inverter 11W to generate a three-phase AC voltage. Three-phase AC power output from the AC side of the inverter system 10 is supplied to the rotating electric machine 30. Specifically, the three-phase AC power is supplied to the stator winding 381, and the stator 38 generates a driving force that rotates the rotor 34.

[0041] The short circuit monitoring unit 22 detects an excessive current flowing through each inverter, thereby monitoring a short circuit in the rotating electric machine 30. A current sensor is provided on the AC circuit side of each inverter, and the short circuit monitoring unit 22 determines a short circuit by receiving an input of a current detection value from the current sensor. Each inverter may be provided with a fuse, and the fuse may be cut when an excessive current flows, and the short circuit monitoring unit 22 may detect the breakage of the fuse.

[0042] 8 is a DC power supply, but the input power supply of the inverter system 10 may be an AC power supply. In the case of an AC power supply, the AC is converted to DC at the input section of the inverter system 10 and supplied to each inverter, and each inverter converts it back to AC and outputs it.

[0043] Fig. 10 is a diagram showing a modified example of the excitation circuit 70 of the locking electromagnet 60. In the modified excitation circuit 70 shown in Fig. 10, a fixed-side circuit 81 has an inverter 92 instead of a switch 84, an excitation power supply 82 is connected to the input side of the inverter 92, and a fixed-side winding 86 is connected to the output side of the inverter 92. This differs from Fig. 5 in that the fixed-side winding 86 is excited with AC by operating the inverter 92, instead of being excited with DC by turning on the switch 84.

[0044] The electromotive force of the electric energy generated in the rotor winding 76 by electromagnetic induction depends on the rate of change per unit time of the magnetic flux of the alternating magnetic field. In other words, if the electromotive force is e, the magnetic flux is Φ, and the time is t, then Faraday's law gives the relation e=k×ΔΦ / Δt, where k is a proportionality constant.

[0045] 5, if the propeller 110 does not move while the ship 100 is stopped, no alternating magnetic flux is generated in the rotating side winding 76 of the rotating side circuit 71. Even if the ship 100 is not completely stopped, when the ship 100 is moving at a low speed and the propeller 110 is rotating at a low speed, the rate of change of the magnetic flux of the alternating magnetic field is small. If the electromotive force of the rotating side winding 76 is small, the output of the rotating rectifier 74 becomes insufficient, and the lock pin 50 cannot be moved by exciting the locking electromagnet 60, and the lock pin 50 may not be released.

[0046] An alternating magnetic field of a predetermined magnetic flux is created by AC exciting the fixed winding 86 using the inverter 92, and the rate of change of the magnetic flux per unit time is increased. This makes it possible to reliably remove the lock pin 50 from the rotor 34 by exciting the locking electromagnet 60, even when the ship 100 is stopped or proceeding at a low speed. Since the generation of electromotive force in the rotor 34 can be prevented, electric shock during maintenance work can be avoided and energy loss can be reduced.

[0047] Furthermore, the rotation speed of the propeller 110 of the ship 100 may be detected, and the output frequency of the inverter 92 may be controlled in accordance with the rotation speed of the propeller 110. Alternatively, the output current of the inverter 92 may be controlled. In this way, even if the speed of the ship 100 (the rotation speed of the propeller 110) changes, it is possible to always keep the frequency of the alternating magnetic flux caused by electromagnetic induction constant, and the current passed through the locking electromagnet 60 can be stabilized, making it possible to stabilize the operation of the lock pin.

[0048] The excitation power supply 82, which is the input power supply of the inverter 92, may be a DC power supply or an AC power supply. In the case of an AC power supply, the AC power supply is converted to DC at the input section of the inverter 92, and then converted back to AC for output. The capacity of the inverter 92 may be smaller than the capacity of the inverter system 10.

[0049] An example of a process flow for operating the lock pin 50 in a system including the rotating electric machine 30 of the embodiment having the configuration described above will be described below. Fig. 11 is a flowchart showing the operation of the system including the rotating electric machine 30 of the embodiment.

[0050] In step S1, it is determined whether or not the short circuit monitoring unit 22 of the inverter system 10 has detected a short circuit in the rotating electric machine 30. The inverter system 10 is equipped with a current sensor, and the short circuit monitoring unit 22 determines whether or not a short circuit has been detected by determining whether or not an excessively large current is flowing based on a current detection value from the current sensor.

[0051] When a short circuit in the rotating electric machine 30 is detected (YES in step S1), an emergency stop operation is performed in step S2 to stop the inverter system 10. The voltage output of the inverter system 10 is stopped, thereby stopping the inverter system 10.

[0052] Next, in step S3, it is confirmed whether the rotation of the rotor shaft 40 has stopped. A rotation position detector such as a resolver is attached to the rotor shaft 40, and based on the detection result of the rotation position detector, it is determined whether the rotor shaft 40 is still rotating or whether the rotation of the rotor shaft 40 has stopped. If the rotation of the rotor shaft 40 has not stopped (NO in step S3), the determination in step S3 is repeated, and the system waits until the rotation of the rotor shaft 40 has stopped.

[0053] When the rotation of the rotor shaft 40 has stopped (YES in step S3), in step S4, the locking electromagnet 60 is excited. The locking electromagnet 60 may be excited automatically by a program, or may be excited manually.

[0054] By exciting the locking electromagnet 60, the lock pin 50 moves away from the rotor 34, and the physical connection between the rotor shaft 40 and the rotor 34 is released. In this state, due to the effect of the rolling bearings 42, 44, the rotor 34 does not rotate even when the rotor shaft 40 rotates, and the rotor shaft 40 goes into an idling state. Therefore, even if an interphase short circuit occurs in the stator windings of the rotating electric machine 30, no voltage is generated in the stator windings of the rotating electric machine 30 due to the effect of the induced voltage of the permanent magnets, and the continuation of the short circuit can be suppressed.

[0055] Next, in step S5, a recovery process is performed for the short-circuited portion. If a fuse is provided in each inverter and the fuse has been blown due to an excessive current, the fuse is also replaced.

[0056] Next, in step S6, it is determined whether the short circuit has been restored. If the current sensor does not detect an excessive current when the inverter system 10 is restarted, it is determined that the short circuit has been restored. If each inverter is provided with a fuse and the fuse was blown by the excessive current, it is determined that the short circuit has been restored by replacing the fuse. If the short circuit has not been restored (NO in step S6), the process returns to step S5 and the restoration process is repeated.

[0057] When the short circuit is restored (YES in step S6), in step S7, the locking electromagnet 60 is de-energized and operation continues. By de-energizing the locking electromagnet 60, the lock pin 50 moves into the recess 36 of the rotor 34 by the biasing force of the spring 54, and the rotor 34 and the rotor shaft 40 are mechanically coupled to each other.

[0058] At this time, depending on the stopping position of the rotor shaft 40, the recess 66 of the locking electromagnet 60 may not be aligned with the recess 36 of the rotor 34. In that case, the position of the rotor 34 can be adjusted manually, or the inverter system 10 can be driven to rotate the rotor 34 so that the recess 36 of the rotor 34 and the recess 66 of the locking electromagnet 60 are aligned, and the lock pin 50 can be automatically restored by the biasing force of the spring 54 at the moment the recess 36 and the recess 66 are aligned.

[0059] If a short circuit in the rotating electrical machine 30 is not detected in the determination in step S1 (NO in the determination in step S1), the process of operating the lock pin 50 is not executed, and the process proceeds to step S8 to continue operation as is. Then, the process ends ("END" in FIG. 11).

[0060] The present invention is not limited to the above-described example of the process of detecting a short circuit and activating the lock pin 50. For example, in the system shown in Fig. 1, the locking electromagnet 60 may be excited to disconnect the rotor 34 from the locking electromagnet 60 when the vessel 100 is stopped, and the excitation of the locking electromagnet 60 may be released to connect the rotor 34 to the locking electromagnet 60 when the vessel 100 starts to propel. For example, in the system shown in Fig. 2, the locking electromagnet 60 may be excited to disconnect the rotor 34 from the locking electromagnet 60 when no power generation is performed by the rotating electric machine 30, and the excitation of the locking electromagnet 60 may be released to connect the rotor 34 to the locking electromagnet 60 when power generation starts.

[0061] Although some of the description overlaps with the above description, the characteristic configurations and effects of the embodiment can be summarized as follows.

[0062] 6 and 7, the lock pin 50 moves in the axial direction by excitation of the locking electromagnet 60, thereby switching between connection and disconnection between the rotor 34 and the locking electromagnet 60. When the rotor 34 and the locking electromagnet 60 are in a disconnected state, the rolling bearings 42, 44 are interposed between the rotor 34 and the rotor shaft 40, so that the rotor 34 is not linked to the rotation of the rotor shaft 40. Even if the rotor shaft 40 is rotated by an external force, the rotor 34 does not rotate, so the permanent magnet of the rotor 34 does not generate an induced voltage. Even if a short circuit occurs between phases or turns in the stator winding of the rotating electric machine 30, the induced voltage can be suppressed from causing the short circuit to continue, and damage can be prevented from expanding.

[0063] Since it is possible to prevent induced voltage from being generated in the permanent magnets of the rotor 34 without providing a large-scale device such as a clutch or brake device to the rotor shaft 40, it is possible to suppress the continuation of a short circuit due to induced voltage with a simple configuration. Since the rotor shaft 40 and the rotor 34 can be separated inside the rotating electric machine 30, it is possible to achieve space saving.

[0064] As shown in Figures 6 and 7, the spring 54 may bias the lock pin 50 in a direction opposite to the direction of movement of the lock pin 50 caused by the excitation of the locking electromagnet 60. With the locking electromagnet 60 in an excited state, the lock pin 50 can be moved to the left in Figures 6 and 7 to disconnect the rotor 34 from the locking electromagnet 60. By releasing the excitation of the locking electromagnet 60, the lock pin 50 can be moved to the right in Figures 6 and 7 by the biasing force of the spring 54. The lock pin 50 can be restored to a state in which the tip surface 51 of the lock pin 50 is disposed in the recess 36 of the rotor 34 and the base end surface 52 is disposed in the recess 66 of the locking electromagnet 60, thereby connecting the rotor 34 and the locking electromagnet 60 via the lock pin 50.

[0065] 5 and 10, the locking electromagnet 60 may be excited by a direct current rectified by a rotary rectifier 74. A rotary rectifier is usually provided in a synchronous machine to pass a direct current through the excitation winding of the rotor. When the rotor 34 is a permanent magnet rotor as in the embodiment, the rotary rectifier 74 is essentially unnecessary since the rotor 34 does not have an excitation winding. However, by using the rotary rectifier 74 as an electromagnet power supply to pass a direct current through the electromagnet coil 72, the locking electromagnet 60 can be reliably excited to operate the lock pin 50.

[0066] 8, the inverter system 10 may have a short circuit monitoring unit 22 that monitors a short circuit in the rotating electric machine 30. When the short circuit monitoring unit 22 detects a short circuit, the rotor 34 and the locking electromagnet 60 are disconnected from each other, allowing the rotor 34 and the rotor shaft 40 to rotate relative to each other. This eliminates the induced voltage generated by the rotation of the rotor 34, making it possible to reliably suppress the continuation of short circuits between phases or turns and prevent damage from expanding.

[0067] 11, the system may be controlled so that the locking electromagnet 60 is excited when a short circuit in the rotating electric machine 30 is detected, and the excitation of the locking electromagnet 60 is released when the short circuit is restored. When a short circuit is detected, the locking electromagnet 60 is excited to move the lock pin 50, thereby disconnecting the rotor 34 from the locking electromagnet 60 and reliably realizing a state in which the rotor 34 does not generate an induced voltage. When the short circuit is restored, the excitation of the locking electromagnet 60 is released and the lock pin 50 is moved to its original position, allowing operation to continue.

[0068] 10, the excitation circuit 70 may have an inverter 92, and the stator winding 86 may be supplied with power by the inverter 92. By AC exciting the stator winding 86 using the inverter 92, an alternating magnetic field of a predetermined magnetic flux can be created and the rate of change of the magnetic flux per unit time can be kept at a predetermined magnitude, so that the lock pin 50 can be reliably disengaged from the rotor 34 by exciting the locking electromagnet 60.

[0069] As shown in FIGS. 1 and 2, the system of the embodiment may be mounted on a ship 100. In the ship 100, the propeller 110 may receive a force due to an ocean current while the ship 100 is stopped, causing the propeller shaft 111 to rotate. In the system of the embodiment, the lock pin 50 is moved by exciting the locking electromagnet 60, and the rotor shaft 40 connected to the propeller shaft 111 and the rotor 34 can be made to rotate relatively. Even if the propeller shaft 111 rotates, the rotor 34 does not rotate. Therefore, even if a phase-to-phase short circuit occurs in the stator winding of the rotating electric machine 30, the induced voltage of the rotor 34 can reliably suppress the continuation of the phase-to-phase short circuit, and damage can be prevented from expanding. In this way, a safer ship 100 can be realized.

[0070] The embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0071] 1 power supply, 10 inverter system, 11U, 11V, 11W, 92 inverter, 20 monitoring control device, 21 single-phase inverter control unit, 22 short circuit monitoring unit, 30 rotating electric machine, 31 housing, 34 rotor, 35 end face, 36, 66 recess, 38 stator, 40 rotor shaft, 42, 44 rolling bearing, 50 lock pin, 51 tip face, 52 base end face, 54 spring, 60 locking electromagnet, 65 opposing face, 67 bottom face, 70 excitation circuit, 71 rotating side circuit, 72 electromagnet coil, 74 rotating rectifier, 76 rotating side winding, 78, 88 connection cable, 81 fixed side circuit, 82 excitation power supply, 84 switch, 86 fixed side winding, 90 excitation winding, 100 ship, 110 propeller, 111 Propeller shaft, 120 engine.

Claims

1. A rotor shaft extending in an axial direction; a rotating electric machine including a rotor provided radially outward of the rotor shaft and a stator provided radially outward of the rotor; a bearing interposed between the rotor shaft and the rotor to enable relative rotation between the rotor shaft and the rotor; A locking electromagnet fixed to the rotor shaft; a locking member that moves in the axial direction when the locking electromagnet is excited, thereby switching between connection and disconnection between the rotor and the locking electromagnet.

2. 2. The system including a rotating electric machine according to claim 1, further comprising a biasing member that biases the locking member in a direction opposite to a moving direction of the locking member caused by excitation of the locking electromagnet.

3. Further, an excitation circuit for exciting the locking electromagnet is provided. the excitation circuit has a primary winding and a secondary winding fixed to the rotor shaft, and is configured to be able to supply electric power from the primary winding to the secondary winding in a non-contact manner by electromagnetic induction, and further has a rotary rectifier, and the secondary winding is configured to be able to supply electric power to the rotary rectifier; 3. The system including a rotating electric machine according to claim 1, wherein the locking electromagnet is excited by a direct current rectified by the rotating rectifier.

4. an inverter system for supplying power to the rotating electric machine; The inverter system has a short circuit monitoring unit that monitors a short circuit of the rotating electric machine, and excites the locking electromagnet when a short circuit of the rotating electric machine is detected, and de-excites the locking electromagnet when the short circuit is restored. A system including a rotating electric machine as described in claim 1 or claim 2.

5. The excitation circuit includes an inverter. The system including the rotating electric machine according to claim 3 , wherein the primary winding is supplied with power by the inverter.

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