Rotary electric machine and engine generator system

Abstract

The present invention provides a rotary electric machine and an engine generator system capable of ensuring reliability by reducing an influence of heat from the rotary electric machine on a control device directly mounted on the rotary electric machine (motor or generator) in an axial-flow open-type cooling system.　The rotary electric machine comprises: a rotor and a stator; ducts arranged on an outer peripheral surface of the stator at a plurality of intervals in a circumferential direction, through which a refrigerant flows, the refrigerant flowing inside the rotary electric machine in an axial direction of a rotating shaft of the rotor; a terminal box arranged at an upper part of the rotary electric machine; and a control circuit for controlling a stator voltage and an excitation current of the rotor, the control circuit being arranged in the terminal box so as to face an inflow direction of the refrigerant. A circumferential position of the ducts in a cross section perpendicular to the rotating shaft of the rotor is set so that a radial distance between the control circuit and the ducts in the cross section perpendicular to the rotating shaft of the rotor is shortest.

Description

Rotating Electric Machine and Engine Generator System

[0001] The present invention relates to a rotating electric machine including a rotor and a stator, and an engine generator system using the same.

[0002] In recent years, due to the influence of global warming, natural disasters caused by climate change have occurred frequently around the world. Also, in Japan, the frequency of earthquake disasters including the Great East Japan Earthquake has been increasing. To prepare for such disasters, ensuring and promptly restoring lifelines are highly emphasized. Among lifelines, power is essential for operating major facilities such as water supply and communication. As a method for directly supplying power to such facilities during disasters, mobile power vehicles are used. Engine generators are used in mobile power vehicles, similar to emergency generators. Since a field current can be controlled to output the same voltage as the grid, a field winding type synchronous generator is used for the generator.

[0003] For a power supply system mounted on a vehicle, the system itself is required to be small and lightweight. The same applies to peripheral devices connected to the generator, which need to be installed in the limited space on the vehicle (trailer). Therefore, in order to prioritize size reduction and weight reduction and make it work as a generator, improvement of cooling performance is essential. There are various cooling methods for generators, but the cooling method with a simple structure and high cooling performance is the axial flow open type. It is a structure in which the inside and outside (outside air) of the generator are directly connected. Among the above-mentioned peripheral devices, an important device for the generator is an automatic voltage regulator (hereinafter referred to as AVR). The AVR is a device that controls the field current supplied to the field winding of the rotor to keep the output voltage constant. In an emergency generator or the like, the AVR is arranged in a control panel or the like installed separately from the generator. However, when mounted on a power vehicle, the AVR is mounted on the generator main body to save space.

[0004] Since AVRs are electronic devices composed of semiconductors and ICs, it is necessary to minimize the effects of external disturbances (vibration, temperature) and ensure the integrity of the AVR. For this reason, methods and positions for mounting the AVR have been studied to reduce disturbances from the generator, and Patent Document 1 is an example of this. In Patent Document 1, cooling fins are provided on the motor, and a case containing the terminals and inverter is installed on top of the motor.

[0005] U.S. Patent Application Publication No. 2015 / 0076942

[0006] The electric motor described in Patent Document 1 consists of three main components: an inverter, a case with terminals, the motor body frame, and a rotor and stator. The stator is connected to the inner surface of the frame on its entire circumference, and cooling fins are arranged around the outer circumference of the frame. The heat generated from the stator is transmitted to the frame and dissipated through the fins on the outer circumference of the frame. For low-capacity machines up to several tens of kilowatts at low voltage, the cooling performance is usually satisfactory, but for high-capacity machines of several thousand kilowatts or more at high voltage, cooling with only the fins around the outer circumference of the frame becomes insufficient. Focusing on the flow of the refrigerant, a fan is connected to the axial end of the rotor's rotation shaft. The refrigerant flows axially through the fins to cool the motor. The temperature at the refrigerant inlet is low, and as it flows axially, the temperature of the refrigerant rises before it flows out into the atmosphere. That is, a temperature distribution occurs in the axial direction of the refrigerant itself (detailed in the embodiment). At this time, it is thought that the case with terminals and an inverter is also affected by the temperature rise of the refrigerant. In the configuration of Patent Document 1, the refrigerant flows out to the fan side, so the equipment inside the case located at the fan end will be hotter than the equipment on the opposite side of the fan. However, Patent Document 1 does not take into consideration the fact that electronic equipment such as inverters generate heat themselves and therefore need to be positioned so as not to be affected by the heat generated by the motor.

[0007] Therefore, the present invention provides a rotating electric machine and engine generator system that reduces the influence of temperature from the rotating electric machine on a control device directly mounted on the rotating electric machine (motor or generator) using an axial flow open-type cooling system, thereby ensuring reliability.

[0008] To solve the above problems, the present invention provides a rotating electric machine comprising a rotor and a stator, wherein a coolant flows in the axial direction of the rotor's rotation axis inside the rotating electric machine, a duct arranged on the outer surface of the stator through which the coolant flows at multiple intervals in the circumferential direction, a terminal box located at the top of the rotating electric machine, and a control circuit for controlling the stator voltage and the excitation current of the rotor, wherein the terminal box is positioned opposite to the direction of coolant inflow, and the circumferential position of the duct in a cross section perpendicular to the rotor's rotation axis is positioned such that the radial distance between the control circuit and the duct in a cross section perpendicular to the rotor's rotation axis is minimized.

[0009] Furthermore, the engine generator system according to the present invention is an engine generator system comprising a rotating electric machine, an engine, and a load machine, wherein the rotating electric machine generates electricity and supplies power when the engine is driven, and the rotating electric machine comprising a rotor and a stator comprises a refrigerant flowing in the axial direction of the rotor's rotation axis inside the rotating electric machine, a duct arranged on the outer circumferential surface of the stator through which the refrigerant flows at multiple intervals in the circumferential direction, a terminal box located at the top of the rotating electric machine, and a control circuit for controlling the stator voltage and the excitation current of the rotor, wherein the terminal box is arranged to face the direction of the refrigerant inflow, and the circumferential position of the duct in a cross section perpendicular to the rotor's rotation axis is arranged such that the radial distance between the control circuit and the duct in a cross section perpendicular to the rotor's rotation axis is minimized.

[0010] According to the present invention, it is possible to provide a rotating electric machine and engine generator system that reduces the temperature influence from the rotating electric machine on a control device directly mounted on the rotating electric machine (motor / generator) using an axial flow open-type cooling system, thereby ensuring reliability. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

[0011] This is a 1 / 2 cross-sectional view in the axial direction of the rotor shaft of a rotating electric machine according to Embodiment 1 of the present invention. This is a cross-sectional view taken along the line A-A' in Figure 1. This is a cross-sectional view taken along the line B-B' in Figure 1. This is a diagram showing the temperature distribution at the frame axial position. This is a 1 / 2 cross-sectional view in the axial direction of the rotor shaft of a rotating electric machine according to Embodiment 2 of the present invention. This is a 1 / 2 cross-sectional view in the axial direction of the rotor shaft of a rotating electric machine according to Embodiment 2 of the present invention. This is a 1 / 2 cross-sectional view in the axial direction of the rotor shaft of a rotating electric machine according to Embodiment 3 of the present invention. This is a 1 / 2 cross-sectional view in the axial direction of the rotor shaft of a rotating electric machine according to Embodiment 3 of the present invention. This is a radial 1 / 2 cross-sectional view of the rotor of a rotating electric machine according to Embodiment 4 of the present invention. This is a 1 / 2 cross-sectional view in the axial direction of the rotor shaft of a rotating electric machine according to Embodiment 5 of the present invention. This is a 1 / 2 cross-sectional view in the axial direction of the rotor shaft of a rotating electric machine according to Embodiment 6 of the present invention. This is a schematic configuration diagram of an engine generator system according to Embodiment 7 of the present invention. This is a schematic configuration diagram of an engine generator system according to Embodiment 7 of the present invention.

[0012] The embodiments of the present invention will be described below with reference to the drawings. In each figure, the same parts are denoted by the same reference numerals.

[0013] Figure 1 is a 1 / 2 axial cross-sectional view of the rotor's rotation shaft of a rotating electric machine according to Embodiment 1 of the present invention. The rotating electric machine 100 according to this embodiment is a rotating electric machine mainly used in connection with an engine. The output is several thousand kVA, the voltage is several tens of kV, and the rotation speed is several thousand min- １ This is a class of rotating electric machine, applicable as a power source for pumps, compressors, fans, etc., as well as for emergency power supply.

[0014] As shown in Figure 1, the rotating electric machine 100 has a rotor 2 and a stator 3 arranged within a frame 1. The frame 1 is provided with a bearing 4 for the rotor 2 to rotate. A shaft 5 and a fan 6 are fastened to the rotor 2. Furthermore, the rotor 2a of the AC excitation device 7, the rotor 2b of the permanent magnet generator 8, and the rotating rectifier circuit 9 are fastened to the shaft 5, which are located outside the bearing 4 on the left side of Figure 1.

[0015] The AC excitation device 7 is a rotating electric machine that supplies current to the field coil 14 wound around the rotor core 12 of the rotor 2. The output of the AC excitation device 7 is three-phase AC power, which is connected to the rotary rectifier circuit 9, converted to DC current, and supplied to the field coil 14.

[0016] A terminal box 10 is positioned on the upper part of frame 1, and a control circuit 11 is positioned on the axial end face of the rotor 2's rotation shaft within the terminal box 10. The control circuit 11 is a control circuit for keeping the voltage of the stator 3 constant. In order to keep the voltage of the stator 3 constant, it is necessary to control the DC current supplied to the field coil 14, and the output from the control circuit 11 is electrically connected to the stator 3a of the AC excitation device 7. This keeps the voltage of the stator 3 constant. The power from the permanent magnet generator 8 is used as the power source for driving the control circuit 11 and for supplying power to the AC excitation device 7. Therefore, the stator 3b of the permanent magnet generator 8 is electrically connected to the control circuit 11.

[0017] By arranging the AC excitation device 7 and the permanent magnet generator 8 on the outside of the bearing 4, the distance between the left bearing 4 and the right bearing 4 on Figure 1, which supports the rotor 2, can be reduced, thereby increasing the vibration frequency and improving the reliability of the rotor 2.

[0018] Figure 2 is a cross-sectional view taken along the line A-A' in Figure 1. Figure 2 shows a cross-section of one pole of the rotor 2 and stator 3. As shown in Figure 2, the main components constituting the rotor 2 and stator 3 are the rotor core 12, the stator core 13, the field coil 14, the stator coil 15, the gap 16, the damper bar 17, the stator wedge 18, and the intermediate ducts 19, 19a.

[0019] By arranging the intermediate ducts 19 and 19a, flow paths 21 and 21a are formed through which the refrigerant 20 flows in the axial direction. The refrigerant 20 flows through flow path 21, which is between the intermediate duct 19 and the field coil 14, and through flow path 21a, which is between the intermediate duct 19a and the stator coil 15. The refrigerant 20 in Figure 2 is the refrigerant generated by the fan action (Euler head pressure) caused by the rotation of the rotor 2.

[0020] Next, the flow of refrigerant 20 throughout the rotating electric machine 100 will be explained. The arrows shown in Figures 1 and 2 indicate the flow of refrigerant 20. The flow path for refrigerant 20 flows in from inlets 22 and 22a in Figure 1, and branches out to flow into the rear duct 23, gap 16 (Figure 2), and inter-pole section 24 (Figure 2). The aforementioned flow path 21 for refrigerant 20 is connected to gap 16, and gap 16 is further connected to flow path 21a. Since flow path 21a is connected to rear duct 23, the refrigerant 20 that has passed through flow path 21a flows into rear duct 23. The refrigerant 20 that has flowed into rear duct 23, gap 16, and inter-pole section 24 flows in the axial direction of the rotor 2's rotation shaft and is released into the atmosphere from outlet 25.

[0021] The refrigerant 20 flowing through the rear duct 23 and the flow path 21a mainly reduces the temperature rise caused by iron loss in the stator core 13 and copper loss in the stator coil 15. The refrigerant 20 flowing through the gap 16 mainly reduces the temperature rise caused by iron loss in the stator core 13, copper loss in the stator coil 15 and copper loss in the field coil 14. The refrigerant 20 flowing through the inter-pole section 24 and the flow path 21 mainly reduces the temperature rise caused by iron loss in the rotor core 12 and copper loss in the field coil 14.

[0022] Figure 3 is a cross-sectional view taken along the line B-B' in Figure 1. As shown in Figure 3, the rear duct 23 is formed in the circumferential direction of the stator 3 (circumferential direction in a cross-section perpendicular to the rotation axis of the rotor 2), with a gap on the outer circumference side of the stator 3 (stator core 13). This is achieved by providing a protrusion 26 on the inner circumference side of the frame 1 and fastening the protrusion 26 to the outer circumference of the stator 3, thereby holding the stator 3. With this structure, the rear duct 23 can be formed without adding any parts, and the stator 3 can also be held. In addition, since the refrigerant 20 is in direct contact with the outer surface of the stator core 13, the heat dissipation effect can also be increased.

[0023] Here, since the protrusion 26 is in contact with the stator 3, heat from the stator 3 also passes through the protrusion 26. The heat that passes through the protrusion 26 is dissipated to the atmosphere via the frame 1. Therefore, when comparing the temperatures at points A and B in Figure 3, point B is a part of the frame 1 located outside the rear duct 23, so it is clear that the temperature will be lower than at point A. As shown in Figures 3 and 1, the terminal box 10 and the control circuit 11 are connected to the upper part of the frame 1. In particular, since we want to avoid the effects of temperature on the control circuit 11 as described above, the influence of heat dissipation from the rotating electric machine 100 should be reduced as much as possible. For this reason, as shown in Figure 3, the positional relationship between the rear duct 23 and the control circuit 11 is important, and it is essential to form the rear duct 23 so that the radial distance between the rear duct 23 and the control circuit 11 (the radial distance in a cross section perpendicular to the rotation axis of the rotor 2) is minimized. Conversely, a configuration that is susceptible to thermal influence is one in which the radial distance between the protrusion 26 and the control circuit 11 (the radial distance in a cross section perpendicular to the rotation axis of the rotor 2) is minimized. Therefore, the relationship between the circumferential width of the protrusion 26 (the circumferential width in a cross section perpendicular to the rotation axis of the rotor 2) and the circumferential width of the rear duct 23 (the circumferential width in a cross section perpendicular to the rotation axis of the rotor 2) is important, and the condition is that the circumferential width of the rear duct 23 (the circumferential width in a cross section perpendicular to the rotation axis of the rotor 2) is greater than the circumferential width of the protrusion 26 (the circumferential width in a cross section perpendicular to the rotation axis of the rotor 2). The above explanation describes a configuration that can reduce the influence of the radial temperature distribution (radial direction in a cross section perpendicular to the rotation axis of the rotor 2) on the control circuit 11.

[0024] The same can be said for the temperature distribution in the axial direction (the axial direction of the rotor 2's rotation axis). As shown in Figure 1, the refrigerant 20 flows from the left side of the paper to the right side. The refrigerant 20 that flows in from the inlet 22 is at the same temperature as the ambient temperature and flows to the outlet 25 while absorbing heat from the rotating electric machine 100. In other words, the refrigerant 20 itself will have a temperature distribution due to the temperature rise in the axial direction (the axial direction of the rotor 2's rotation axis). Figure 4 is a diagram showing the temperature distribution at the frame axial position. As shown in Figure 4, the temperature rise of the frame 1 on the inlet side (inflow side) is set to a normalized value (p.u.) of 1.0. As shown in Figure 4, the temperature increases from the inlet side (inflow side) to the exhaust side (outflow side). The frame axial position where the temperature is highest is between the axial center of the stator 3 and the exhaust side (outflow side). For this reason, it is important to place the control circuit 11 on the inlet side (inflow side) in order to reduce the effect of heat dissipation from the rotating electric machine 100. The above configuration reduces the influence of external heat on the control circuit 11, thereby ensuring reliability.

[0025] In this embodiment, the rotating electric machine 100 has four poles on the rotor 2 and sixty slots on the stator 3, but other numbers of poles and slots are also acceptable. Furthermore, the intermediate ducts 19 and 19a, arranged in the axial direction (the axial direction of the rotor 2's rotation axis), have seven stages, but other numbers of stages are also acceptable.

[0026] As described above, this embodiment makes it possible to reduce the temperature influence from the rotating electric machine (motor / generator) on a control device directly mounted on the rotating electric machine using an axial flow open-type cooling system, thereby providing a rotating electric machine that can ensure reliability.

[0027] Figure 5 is a 1 / 2 axial cross-sectional view of the rotor's rotation axis of a rotating electric machine according to Embodiment 2 of the present invention. This embodiment differs from Embodiment 1 described above in that the terminal box 10 is located at the axial end (axial direction of the rotor's rotation axis) of the frame 1 on the refrigerant inflow side of the refrigerant 20. Other aspects are the same as in Embodiment 1, and in the following, the same reference numerals are used for the same components as in Embodiment 1, and their descriptions are omitted.

[0028] As shown in Figure 5, the rotating electric machine 100a according to this embodiment is configured to have the terminal box 10 installed at the axial end (axial direction of the rotor 2's rotation axis) of the frame 1 on the side where the refrigerant 20 flows in. As shown in Embodiment 1 above, the temperature of the rotating electric machine 100a is lower on the side where the refrigerant 20 flows in, so by installing the terminal box 10 at the end of the frame 1 on the side where the refrigerant 20 flows in, the influence of temperature from the rotating electric machine 100a can be further reduced. Figure 6 is a 1 / 2 cross-sectional view in the axial direction of the rotor's rotation axis of the rotating electric machine according to Embodiment 2 of the present invention. In Figure 5, the control circuit 11 and the end face of the frame 1 are aligned, but in order to ensure a good seating and stability of the terminal box 10, it is preferable to install it on the entire surface of the frame 1. For this reason, as shown in Figure 6, the control circuit 11 does not need to be located on the top of the frame 1, and may be installed with an overhang.

[0029] As described above, this embodiment provides the same cooling effect as the embodiment 1, but with an improved cooling effect. Furthermore, it facilitates the installation of the terminal box (making positioning easier).

[0030] Figure 7 is a 1 / 2 cross-sectional view in the axial direction of the rotor's rotation axis of a rotating electric machine according to Embodiment 3 of the present invention. This embodiment differs from Embodiment 1 described above in that the inlet 22b is positioned in the radial direction of the frame 1 (radial direction in the cross-section perpendicular to the rotation axis of the rotor 2). Other aspects are the same as in Embodiment 1, and in the following, the same reference numerals are used for the same components as in Embodiment 1, and their descriptions are omitted.

[0031] As shown in Figure 7, in this embodiment, the rotating electric machine 100b has an inlet 22b located on the frame 1 positioned in the radial direction of the frame 1 (radial direction in a cross-section perpendicular to the rotation axis of the rotor 2). By positioning the inlet 22b in the radial direction (radial direction in a cross-section perpendicular to the rotation axis of the rotor 2), the refrigerant 20 flowing into the inlet 22b is close to the control circuit 11, so that the control circuit 11 can be cooled together with the rotating electric machine 100b, and a temperature reduction effect against the heat generated by the control circuit 11 itself can also be expected. Figure 8 is a 1 / 2 cross-sectional view in the axial direction of the rotation axis of the rotor of the rotating electric machine according to Embodiment 3 of the present invention. As shown in Figure 8, similar to Embodiment 2 described above, it is also acceptable to install the control circuit 11 with an overhang in the axial direction of the frame 1 (radial direction in a cross-section perpendicular to the rotation axis of the rotor 2).

[0032] As described above, according to this embodiment, in addition to the effects of Embodiment 1, it is possible to improve the cooling effect of the control circuit.

[0033] Figure 9 is a 1 / 2 radial cross-sectional view of the rotor of a rotating electric machine according to Embodiment 4 of the present invention. This embodiment differs from Embodiment 1 in that the width of the rear duct 23 is increased to match the width direction of the control circuit 11. In other words, the width of the rear duct 23 in the circumferential direction (circumferential direction in a cross section perpendicular to the rotation axis of the rotor 2) corresponding to the position of the control circuit 11 is increased, which is different from Embodiment 1. Other aspects are the same as in Embodiment 1, and in the following, the same reference numerals are used for the same components as in Embodiment 1, and their descriptions are omitted.

[0034] As shown in Figure 9, the width of the rear duct 23 in the circumferential direction (circumferential direction in a cross-section perpendicular to the rotation axis of the rotor 2) is unevenly distributed. To reduce the influence of temperature on the control circuit 11, it is preferable to increase the width of the rear duct 23 in the circumferential direction (circumferential direction in a cross-section perpendicular to the rotation axis of the rotor 2) to match the width of the control circuit 11. This further reduces the influence of temperature on the control circuit 11. As shown in Figure 9, if the width of a part of the rear duct 23 in the circumferential direction (circumferential direction in a cross-section perpendicular to the rotation axis of the rotor 2) is increased without changing the number of protrusions 26, the circumferential pitch of the protrusions 26 becomes uneven.

[0035] As described above, according to this embodiment, in addition to the effects of Embodiment 1, the cooling effect on the control circuit is improved by increasing the circumferential width of the rear duct.

[0036] Figure 10 is a 1 / 2 axial cross-sectional view of the rotor's rotation shaft of a rotating electric machine according to Embodiment 5 of the present invention. This embodiment differs from Embodiment 1 in that a magnetic shield (magnetic shielding material) 27 is placed between the terminal box 10 and the control circuit 11. Other aspects are the same as in Embodiment 1, and in the following, the same reference numerals are used for the same components as in Embodiment 1, and their descriptions are omitted.

[0037] As shown in Figure 10, the rotating electric machine 100c according to this embodiment has a magnetic shield (magnetic shielding material) 27 placed between the terminal box 10 and the control circuit 11. As described in Embodiment 1 above, in the case of a rotating electric machine with a high voltage of several tens of kV, there is concern about the effect of electromagnetic waves on surrounding equipment. In particular, the control circuit 11, which uses electronic components, may malfunction, so by placing the (magnetic shielding material) 27 between the terminal box 10 and the control circuit 11, the effects of electromagnetic waves are absorbed and malfunctions of the control circuit 11 are prevented.

[0038] As described above, according to this embodiment, in addition to the effects of Embodiment 1, by placing a (magnetic shielding material) between the terminal box and the control circuit, it is possible to absorb the effects of electromagnetic waves and prevent malfunctions of the control circuit.

[0039] Figure 11 is a 1 / 2 axial cross-sectional view of the rotor's rotation shaft of a rotating electric machine according to Embodiment 6 of the present invention. This embodiment differs from Embodiment 1 in that a cushioning material 28 for preventing vibration is placed between the terminal box 10 and the frame 1. Other aspects are the same as in Embodiment 1, and in the following, the same reference numerals are used for the same components as in Embodiment 1, and their descriptions are omitted.

[0040] As shown in Figure 11, the rotating electric machine 100d according to this embodiment has a damping material 28 placed between the terminal box 10 and the frame 1 to prevent vibration. The rotating electric machine 100d generates vibration in addition to heat, so there is a concern that the vibration may damage components such as stoppers that fix terminals and cables located on the control circuit 11 and terminal box 10. By placing the damping material 28 between the terminal box 10 and the rotating electric machine 100d, vibration from the rotating electric machine 100d can be reduced, and the reliability of the control circuit 11 and terminal box 10 can be maintained. The damping material 28 may be placed so as to make full contact between the terminal box 10 and the frame 1, and the same effect can be obtained by placing it at four points in the four corners of Figure 11.

[0041] As described above, this embodiment provides the same effects as the first embodiment, but also prevents damage to the control circuit and terminal box due to vibration.

[0042] Figure 12 is a schematic diagram of the engine generator system according to Embodiment 7 of the present invention. As shown in Figure 12, the engine generator system according to this embodiment applies one of the rotating electric machines from Embodiments 1 to 6 described above, namely, rotating electric machines 100, 100a, 100b, 100c, and 100d. One of the rotating electric machines 100, 100a, 100b, 100c, and 100d is directly connected to the engine 200 via a coupling 50. When the engine 200 is driven, power is supplied from one of the rotating electric machines 100, 100a, 100b, 100c, and 100d to the electric motor 301. A load device 302 is connected to the electric motor 301. The load device is mainly a fan, compressor, pump, etc. Furthermore, in the case of an emergency power supply, the load device becomes equipment, and power is supplied directly from one of the rotating electric machines 100, 100a, 100b, 100c, or 100d to, for example, communication equipment or data servers, without going through the electric motor 301. Figure 13 is a schematic configuration diagram of an engine generator system according to Embodiment 7 of the present invention. As shown in Figure 13, power from one of the rotating electric machines 100, 100a, 100b, 100c, or 100d is connected to the power converter 300, and power is supplied from the power converter 300 to the electric motor 301. In the case of an emergency power supply, power is supplied from the power converter 300 to the equipment, which is the load device, without going through the electric motor 301, as in Figure 12.

[0043] As described above, according to this embodiment, it is possible to provide an engine generator system that can reduce the influence of the temperature from the rotating electrical machine on the control device directly mounted on the rotating electrical machine (motor / generator) with an axial flow open cooling method and ensure reliability.

[0044] Note that the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can also be added to the configuration of one embodiment.

[0045] 1... Frame 2, 2a, 2b... Rotor 3, 3a, 3b... Stator 4... Bearing 5... Shaft 6... Fan 7... Alternating current excitation device 8... Permanent magnet generator 9... Rotating rectifier circuit 10... Terminal box 11... Control circuit 12... Rotor core 13... Stator core 14... Field coil 15... Stator coil 16... Gap 17... Damper bar 18... Stator wedge 19, 19a... Intermediate duct 20... Refrigerant 21, 21a... Flow path 22, 22a, 22b... Inlet 23... Rear duct 24... Interpolar part 25... Outlet 26... Projection 27... Magnetic shield (magnetic shielding material) 28... Buffer material 50... Coupling 100, 100a, 100b, 100c, 100d... Rotating electrical machine 200... Engine 300... Power converter 301... Motor 302... Load machine

Claims

1. A rotating electric machine comprising a rotor and a stator, wherein a coolant flows in the axial direction of the rotor's rotation axis inside the rotating electric machine, and a duct is arranged on the outer circumferential surface of the stator through which the coolant flows at multiple intervals in the circumferential direction, a terminal box is located at the top of the rotating electric machine, and a control circuit is provided for controlling the stator voltage and the excitation current of the rotor, wherein the terminal box is positioned opposite to the direction of coolant inflow, and the circumferential position of the duct in a cross section perpendicular to the rotor's rotation axis is positioned such that the radial distance between the control circuit and the duct in a cross section perpendicular to the rotor's rotation axis is minimized.

2. A rotating electric machine according to claim 1, wherein the frame has multiple protrusions provided on it at intervals in the circumferential direction for fastening the stator to the frame, the duct is formed between the protrusions, and the circumferential width of the duct is greater than the circumferential width of the protrusions.

3. The rotating electric machine according to claim 2, characterized in that the terminal box is installed in the axial direction of the rotor's rotation shaft and at the frame end on the side where the refrigerant flows in.

4. The rotating electric machine according to claim 3, characterized in that the refrigerant inlet is provided in the radial direction in a cross section of the frame perpendicular to the rotation axis of the rotor.

5. The rotating electric machine according to claim 3, characterized in that the circumferential width of the duct corresponding to the position of the control circuit is greater than the circumferential width of the other ducts.

6. A rotating electric machine according to claim 3, characterized in that a magnetic shielding material is placed between the control circuit and the terminal box.

7. A rotating electric machine according to claim 3, characterized in that a cushioning material is placed between the terminal box and the frame.

8. An engine generator system comprising a rotating electric machine, an engine, and a load machine, wherein the engine drives the rotating electric machine to generate electricity and supply power, the rotating electric machine comprising a rotor and a stator, wherein a coolant flows in the axial direction of the rotor's rotation axis inside the rotating electric machine, a duct arranged on the outer surface of the stator through which the coolant flows at multiple intervals in the circumferential direction, a terminal box located at the top of the rotating electric machine, and a control circuit for controlling the stator voltage and the excitation current of the rotor, wherein the terminal box is positioned opposite to the direction of coolant inflow, and the circumferential position of the duct in a cross-section perpendicular to the rotor's rotation axis is positioned such that the radial distance between the control circuit and the duct in a cross-section perpendicular to the rotor's rotation axis is minimized.

9. An engine generator system according to claim 8, wherein the rotating electric machine has multiple protrusions provided on the frame at intervals in the circumferential direction for fastening the stator to the frame, the duct is formed between the protrusions, and the circumferential width of the duct is greater than the circumferential width of the protrusions.

10. An engine generator system according to claim 9, wherein the rotating electric machine is characterized in that the terminal box is installed at the frame end on the refrigerant inlet side, in the axial direction of the rotor's rotation shaft.

11. An engine generator system according to claim 10, characterized in that the rotating electric machine has a refrigerant inlet provided in the radial direction in a cross section of the frame perpendicular to the rotation axis of the rotor.

12. An engine generator system according to claim 10, wherein the rotating electric machine is characterized in that the circumferential width of the duct corresponding to the position of the control circuit is greater than the circumferential width of the other ducts.

13. An engine generator system according to claim 10, characterized in that the rotating electric machine has a magnetic shielding material placed between the control circuit and the terminal box.

14. An engine generator system according to claim 10, characterized in that the rotating electric machine has a buffer material placed between the terminal box and the frame.

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