JP6154602B2 - Cooling device for rotating electric machine - Google Patents

Description

  The present invention relates to a cooling device for a rotating electrical machine that supplies a cooling liquid to a rotating electrical machine including a stator and a rotor to perform cooling.

  2. Description of the Related Art Conventionally, for example, rotating motors used as motors, generators, or motor generators of hybrid vehicles and electric vehicles have been promoted to be smaller and have higher outputs in order to improve vehicle fuel efficiency (electricity costs). At the same time, it is necessary to sufficiently cool this type of rotating electrical machine in order to ensure the performance in each operation region.

  By the way, in a rotating electrical machine, in general, electrical energy (copper loss) lost due to electrical resistance of a conductive wire constituting a winding, and electrical energy (iron loss) lost when an iron core of a magnetic material is magnetized by alternating current, Will occur. Therefore, in this type of rotating electrical machine, the state of occurrence of energy loss changes depending on the operating state, and the main heat generation site changes. That is, for example, when the rotating electrical machine is operated at a low rotation speed (low speed) and a high torque, the current flowing through the coil increases, and thus the copper loss increases. On the other hand, for example, when the rotating electrical machine is operated at a high rotation (high speed) and a low torque, the iron loss due to the magnetic field disturbance accompanying the high rotation of the rotor becomes large.

  Therefore, for example, Patent Document 1 includes a flow switching unit that selectively switches between a first flow path through which a refrigerant for cooling the permanent magnet flows and a second flow path for cooling the coil, and the rotational speed of the rotating electrical machine is When the rotation speed is equal to or higher than a predetermined switching speed, the refrigerant flows through the first flow path for cooling the permanent magnet. When the rotation speed of the rotating electrical machine is less than the switching rotation speed, the refrigerant flows through the second flow path for cooling the coil. Techniques to do this are disclosed. According to such a technique, when the permanent magnet easily generates heat, the refrigerant is supplied to the permanent magnet, and when the coil easily generates heat, the refrigerant is supplied to the coil, thereby efficiently cooling a portion requiring cooling. It becomes possible to do.

JP 2009-118686 A

  However, as in the technique disclosed in Patent Document 1, in the configuration in which the refrigerant is selectively supplied to either the permanent magnet or the coil, it is difficult to sufficiently cool the rotating electrical machine. There is a fear. That is, for example, in the operation region where heat is generated mainly due to iron loss, if heat generation due to copper loss is not as high as iron loss but is not negligible (or vice versa), as described above. In the configuration in which the refrigerant is selectively supplied to only one of them, it may be difficult to perform sufficient cooling.

  This invention is made | formed in view of the said situation, and it aims at providing the cooling device of the rotary electric machine which can exhibit sufficient cooling capability efficiently in a wide driving | operation area | region.

A cooling apparatus for a rotating electrical machine according to an aspect of the present invention is a cooling apparatus for a rotating electrical machine in which a coil is provided on one of a stator and a rotor and a permanent magnet is provided on the other, and a pump for discharging a refrigerant is upstream. A refrigerant supply passage branched to a first branch passage that is connected to the coil and has a downstream side supplying refrigerant to the coil side, and a second branch passage supplying refrigerant to the permanent magnet side, and the refrigerant supply Switching means interposed in the passage and continuously switching the flow rate distribution of the refrigerant flowing through the first branch passage and the second branch passage; and target torque and target rotation for driving and controlling the rotating electrical machine A total heat generation amount of the rotating electrical machine based on the number , a heat generation amount estimating means for estimating a heat generation amount on the coil side and a heat generation amount on the permanent magnet side, and a total heat generation amount of the rotating electrical machine. Z Flow rate control means for controlling the refrigerant discharge amount from the pump and performing flow rate distribution control of the refrigerant through the switching means on the basis of the respective calorific values on the coil side and the permanent magnet side. It is.

  According to the cooling device for a rotating electrical machine of the present invention, sufficient cooling capacity can be efficiently exhibited in a wide range of operation.

Schematic configuration diagram showing a cooling device for a rotating electrical machine Circuit diagram showing the refrigerant circulation system along with the cross-section of the main part of the rotating electrical machine Flow chart showing a cooling control routine of a rotating electrical machine Explanatory drawing showing a map for heat generation estimation A characteristic diagram showing the relationship between the target rotational speed and the refrigerant distribution amount when the target torque is constant Circuit diagram showing a modification of the refrigerant circulation system together with a cross section of the main part of the rotating electrical machine

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to an embodiment of the present invention, FIG. 1 is a schematic configuration diagram showing a cooling device for a rotating electric machine, FIG. 2 is a circuit diagram showing a refrigerant circulation system together with a cross section of the main part of the rotating electric machine, and FIG. FIG. 4 is an explanatory diagram showing a map for estimating the heat generation amount, FIG. 5 is a characteristic diagram showing the relationship between the target rotational speed and the refrigerant distribution amount when the target torque is constant, and FIG. It is a circuit diagram which shows the modification of the circulation system of a refrigerant | coolant with the principal part cross section of a rotary electric machine.

  1 and 2, reference numeral 1 indicates a high-output type rotating electrical machine that is used, for example, as a driving motor for an electric vehicle.

  As shown in FIG. 2, the rotating electrical machine 1 includes a rotor 6 and a stator 7 that are housed in a housing 5 to form a main part.

  The housing 5 includes a cylindrical housing body 10 having a wall portion 10a on one end side and having the other end side opened, and a lid 11 that closes an opening on the other end side of the housing body 10. It is configured.

  The rotor 6 includes a rotor shaft 15 that is rotatably supported on the wall portion 10 a of the housing 5 and the lid body 11 via a bearing 16. In the present embodiment, a rotor main body 17 composed of a laminated body of a plurality of electromagnetic steel plates having an annular shape is provided on the outer peripheral portion of the rotor shaft 15, for example. Further, the rotor body 17 holds a plurality of permanent magnets 18 at predetermined rotation angles around the rotor shaft 15.

  The stator 7 includes, for example, a stator core 20 made of a laminated body of a plurality of electromagnetic steel plates that form an annular shape. The stator core 20 is held by the housing body 10 with the inner peripheral side facing the rotor 6 with a slight gap. In addition, a plurality of coils 21 are wound around the stator core 20.

  Here, as shown in FIG. 1, a control unit 25 is connected to the coil 21 of the stator 7 via an inverter 22. For example, the control unit 25 sets a target torque and a target rotational speed based on signals from the accelerator opening sensor 26, the vehicle speed sensor 27, and the like, and outputs a control signal corresponding to these to the inverter 22. The inverter 22 supplies a drive current corresponding to the control signal to the coil 21, and the rotor 6 rotates relative to the stator 7 by the electromagnetic force generated in the coil 21 by this drive current.

  Next, the configuration of the cooling device 30 for the rotating electrical machine 1 configured as described above will be described. The cooling device 30 of the present embodiment is an oil-cooled cooling device that cools each part of the rotating electrical machine 1 using, for example, cooling oil as a refrigerant.

  The cooling device 30 has a pump 31 that discharges refrigerant stored in a reservoir tank 32. The pump 31 has a refrigerant branched downstream into a first branch passage 33a and a second branch passage 33b. The upstream end of the supply passage 33 is connected.

  The first branch passage 33a is mainly for supplying refrigerant to the stator 7 side (that is, the coil 21 side in the present embodiment), and the downstream end of the first branch passage 33a is a housing. The refrigerant discharge port 10 b that opens in the main body 10 is communicated. For example, a plurality of the refrigerant discharge ports 10b are provided to face the coil end 21a of the coil 21, and the refrigerant is supplied into the housing 5 through the refrigerant discharge ports 10b, thereby being one of the main heat sources. A certain coil 21 is cooled.

  The second branch passage 33b is mainly for supplying the refrigerant to the rotor 6 side (that is, the permanent magnet 18 side in the present embodiment), and the downstream end of the second branch passage 33b is The refrigerant is communicated with a refrigerant introduction passage 15 a formed in the axial direction of the rotor shaft 15. Here, a plurality of cooling passages 17 a that are close to the permanent magnet 18 are formed in the rotor body 17 at predetermined rotation angles about the rotor shaft 15. One end side of these cooling passages 17 a communicates with the refrigerant introduction passage 15 a, and the other end side is opened in the housing 5. Thus, the refrigerant from the refrigerant introduction passage 15a is circulated in the cooling passage 17a, and the permanent magnet 18 that is one of the main heat sources is cooled by the circulation of the refrigerant.

  Here, a drain opening 10 c for discharging the refrigerant after cooling the rotor 6 and the stator 7 is opened at the bottom of the housing body 10. The drain opening 10 c communicates with the upstream end of the return passage 34. A cooler 35 for cooling the refrigerant is interposed in the middle of the return passage 34, and a reservoir tank 32 is connected to the downstream end of the return passage 34. Thereby, the refrigerant after cooling the rotating electrical machine 1 is cooled by the cooler 35 and then returned to the reservoir tank 32.

  In such a refrigerant circulation system, the refrigerant supply passage 33 is provided with a switching unit 36 as switching means for continuously switching the flow rate distribution of the refrigerant flowing through the first branch passage 33a and the second branch passage 33b. Is intervening. As shown in FIG. 2, in the present embodiment, the switching unit 36 includes a first control valve 36a interposed in the first branch passage 33a and a second control passage 36b interposed in the second branch passage 33b. And a control valve 36b. The first and second control valves 36a and 36b are, for example, driven and controlled together with the pump 31 in the control unit 25. More specifically, the first and second control valves 36a and 36b are For example, it is comprised by the solenoid valve from which the opening degree changes continuously according to the control signal (duty signal etc.) from the control unit 25. FIG.

  Here, for example, the control unit 25 uses the target torque and the target rotational speed described above as parameters indicating the operating state of the rotating electrical machine 1, and calculates the total heat generation amount of the rotating electrical machine 1 based on the target torque and the target rotational speed. In addition to estimation, the heat generation amount on the coil 21 side and the heat generation amount on the permanent magnet 18 side are estimated. Then, the control unit 25 controls the discharge amount from the pump 31 based on the estimated total heat generation amount of the rotating electrical machine 1, and each of the stator 7 side (coil 21 side) and the rotor 6 side (permanent magnet 18 side). Based on the calorific value, refrigerant flow rate distribution control through the control valves 36a, 36b is performed. Thus, in this embodiment, the control unit 25 implement | achieves each function as a emitted-heat amount estimation means and a flow control means.

  Next, the cooling control for the rotating electrical machine 1 executed in the control unit 25 will be described according to the flowchart of the cooling control routine shown in FIG. This routine is repeatedly executed every set time. When the routine starts, the control unit 25 first sets the target torque and the target rotational speed of the rotating electrical machine 1 in step S101. That is, in step S101, the control unit 25 indicates the operating state of the rotating electrical machine 1 based on, for example, the accelerator opening detected by the accelerator opening sensor 26, the own vehicle speed detected by the vehicle speed sensor 27, and the like. A target torque and a target rotational speed are set as parameters.

  When the process proceeds from step S101 to step S102, the control unit 25 estimates the heat loss (heat generation amount) of the rotating electrical machine 1 based on the set target torque and target rotational speed. More specifically, the control unit 25 has, for example, a relationship between a target torque and a target rotational speed obtained in advance through experiments or the like and a heat generation amount (for example, each heat generation amount on the coil 21 side and the permanent magnet 18 side). The control unit 25 refers to this map to estimate the amount of heat generated on the coil 21 side and the permanent magnet 18 side, and the rotary electric machine 1 that is the sum of these values is stored (see FIG. 4). Estimate the total calorific value.

  When the process proceeds from step S102 to step S103, the control unit 25 estimates the required cooling capacity based on the estimated total heat generation amount.

  In subsequent step S104, the control unit 25 sets the pump discharge amount according to the estimated required cooling capacity, and sets the refrigerant distribution amount between the first branch passage 33a side and the second branch passage 33b side. (See, for example, FIG. 5). In addition, the example shown in FIG. 5 shows the relationship between the target rotation speed and the refrigerant distribution amount when the target torque is constant for the sake of simplicity.

  In step S105, the control unit 25 drives and controls the pump 31 based on the set pump discharge amount, and drives and controls the first and second control valves 36a and 36b based on the refrigerant distribution amount. Then exit the routine.

  According to such an embodiment, the downstream side of the refrigerant supply passage 33 that supplies the refrigerant from the pump 31 to the rotating electrical machine 1, the first branch passage 33 a that supplies the refrigerant to the coil 21 side, and the permanent magnet 18 side. The refrigerant supply passage 33 is provided with a switching unit 36 that branches into the second branch passage 33b that supplies the refrigerant to the refrigerant and continuously switches the flow rate of the refrigerant flowing through the first and second branch passages 33a and 33b. In the control unit 25, the total heat generation amount based on the operating state of the rotating electrical machine 1 is estimated, and the heat generation amount on the coil 21 side and the heat generation amount on the permanent magnet 18 side are estimated, respectively. The refrigerant discharge amount from the pump 31 is controlled on the basis of this, and the flow rate distribution control of the refrigerant through the switching unit 36 is performed based on the respective calorific values on the coil 21 side and the permanent magnet 18 side, so that a wide operating range can be obtained. It can be efficiently produced a sufficient cooling capacity in the.

  That is, the total heat generation amount is estimated according to the operating state of the rotating electrical machine 1 to control the refrigerant discharge amount from the pump 31, and the heat generation amounts on the coil 21 side and the permanent magnet 18 side, which are the main heat generation sources, respectively. When the refrigerant is selectively supplied to either the coil side or the permanent magnet side by supplying the refrigerant to each part while continuously changing the flow rate distribution according to the estimated heat generation amount, etc. Compared to the above, cooling of the rotating electrical machine 1 can be realized efficiently and accurately without generating an excessive flow rate of the refrigerant. Therefore, for example, the drive power of the pump 31 can be kept to the minimum necessary, and the power consumption can be suppressed.

  Here, in the above-described embodiment, the first control valve 36a for controlling the flow rate of the first branch passage 33a and the second control valve 36b for controlling the flow rate of the second branch passage 33b are provided. However, for example, as shown in FIG. 6, the switching unit 36 may be configured by only the first control valve 36a that controls the flow rate of the first branch passage 33a. Is possible. According to such a configuration, the balance of the effective diameter between the first and second branch passages 33a and 33b, which changes depending on the opening degree of the first control valve 36a, is obtained by the opening degree control of the first control valve 36a. By changing, the flow distribution can be controlled. In this case, for example, as shown in FIG. 6, the passage diameters of the first branch passage 33a and the second branch passage 33b are made different, and the second branch passage 33b side where no control valve is interposed is provided. By setting the path diameter to be relatively narrower than the path diameter on the first branch passage 33a side, flow control with a wide distribution ratio can be realized by a single control valve (first control valve 36a). it can. If comprised in this way, it will become possible to implement | achieve cooling of the rotary electric machine 1 with a simpler structure. Of course, the switching unit 36 may be configured by only the second control valve 36b instead of the first control valve 36a.

  In addition, this invention is not limited to each embodiment described above, A various deformation | transformation and change are possible, and they are also in the technical scope of this invention. For example, in the above-described embodiment, an example in which the rotating electrical machine 1 is used as a traveling motor has been described. However, the present invention is not limited to this, and for example, the rotating electrical machine is used as a generator or a motor generator. Of course, it may be.

  In the above-described embodiment, an example in which the stator 8 is disposed outside the rotor 6, the permanent magnet 18 is disposed on the rotor 6 side, and the coil 21 is disposed on the stator 7 side has been described. Of course, for example, a coil may be arranged on the rotor side and a permanent magnet may be arranged on the stator side, or the rotor may be arranged outside and the stator arranged inside. .

DESCRIPTION OF SYMBOLS 1 ... Rotating electrical machine 5 ... Housing 5 ... Housing 6 ... Rotor 7 ... Stator 10 ... Housing main body 10a ... Wall part 10b ... Refrigerant discharge port 10c ... Drain opening 11 ... Lid 15 ... Rotor shaft 15a ... Refrigerant introduction passage 16 ... Bearing DESCRIPTION OF SYMBOLS 17 ... Rotor main body 17a ... Cooling passage 18 ... Permanent magnet 20 ... Stator core 21 ... Coil 21a ... Coil end 22 ... Inverter 25 ... Control unit (heat generation amount estimation means, flow rate control means)
26 ... Accelerator opening sensor 27 ... Vehicle speed sensor 30 ... Cooling device 31 ... Pump 32 ... Reservoir tank 33 ... Refrigerant supply passage 33a ... First branch passage 33b ... Second branch passage 34 ... Return passage 35 ... Cooler 36 ... Switching Part (switching means)
36a ... 1st control valve 36b ... 2nd control valve

Claims (4)

A cooling device for a rotating electrical machine in which a coil is provided on either the stator or the rotor and a permanent magnet is provided on the other,
A pump that discharges the refrigerant is connected to the upstream side, and a refrigerant branched into a first branch passage that supplies the refrigerant to the coil side and a second branch passage that supplies the refrigerant to the permanent magnet side A supply passage;
Switching means interposed in the refrigerant supply passage, for continuously switching the flow rate distribution of the refrigerant flowing through the first branch passage and the second branch passage;
The total heat generation amount of the rotating electrical machine is estimated based on the target torque and target rotational speed for driving and controlling the rotating electrical machine, and the heat generation amount for estimating the heat generation amount on the coil side and the heat generation amount on the permanent magnet side, respectively. A quantity estimation means;
The refrigerant discharge amount from the pump is controlled based on the total heat generation amount of the rotating electrical machine, and the refrigerant flow distribution control is performed through the switching means based on the heat generation amounts on the coil side and the permanent magnet side. And a flow rate control means.   2. The rotating electrical machine according to claim 1, wherein the switching unit is configured by a single control valve that adjusts a flow rate of a refrigerant flowing through the first branch passage or the second branch passage. Cooling system.   3. The cooling device for a rotating electrical machine according to claim 1, wherein the flow rate control unit increases the flow rate of the refrigerant flowing through the second branch passage as the rotational speed of the rotor increases. .   The heat generation amount estimation means refers to a map that maps the relationship between the target torque and the target rotation speed, the heat generation amount on the coil side, and the heat generation amount of the permanent magnet, and The cooling device for a rotating electrical machine according to any one of claims 1 to 3, wherein a heat generation amount of the rotating electrical machine that is a sum of heat generation amounts on the permanent magnet side is estimated.

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