Electric drive device and method for controlling electric drive device

Abstract

In a vehicle provided with a motor having a rotor and a stator, and a refrigerant flow path through which a refrigerant for cooling the motor flows, an electric drive device drives the motor by means of a battery, and charges the battery using the motor. The electric drive device is provided with a flow rate adjusting unit for adjusting the flow rate of the refrigerant supplied to the rotor and the stator, and when the battery is charged by energizing the coil of the stator while the vehicle is stopped, the flow rate adjusting unit adjusts the flow rate of the refrigerant supplied to the rotor and the stator. The flow rate adjusting unit switches the flow rate of the refrigerant supplied to the rotor and the stator such that the flow rate of the refrigerant supplied to the stator is increased compared to when the battery is charged without energizing the coil of the stator.

Description

Technical Field

[0001] The present invention relates to an electric drive device and a control method for the electric drive device. Background Art

[0002] To shorten battery charging time while the vehicle is stationary, the battery charging voltage must be increased. For example, if the charging facility voltage and battery voltage are mixed, with voltages of 400V and 800V, respectively, charging an 800V battery with a 400V charger requires boosting the voltage from 400V to 800V. Therefore, using a rapid charging system with a boost chopper circuit that utilizes the three-phase line of the vehicle's traction motor can shorten charging time. However, using a rapid charging system increases the heat generated by the motor, necessitating an increase in the refrigerant flow rate supplied to the motor.

[0003] When increasing the refrigerant flow rate supplied to the motor, for example, the refrigerant liquid level in the motor is controlled to rise. Regarding this liquid level rise, for example, the following patent document 1 discloses a structure of a vehicle control device, which increases the oil level in the motor during deceleration regardless of the charge state of the rechargeable battery. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2018-152946. Summary of the Invention Problems to be solved by the invention

[0005] In view of the technology described in Patent Document 1, during rapid battery charging while the vehicle is stationary, it is necessary to raise the cooling oil level within the motor to prevent the stator coil from heating up due to the motor charging, thereby preventing the stator coil from burning out. In view of this, the present invention aims to provide an electric drive device and a control method for the electric drive device that can improve the cooling of the stator coil during rapid battery charging. Technical means to solve the problem

[0006] An electric drive device and a control method for the electric drive device, in which, in a vehicle having a motor with a rotor and a stator, and a refrigerant flow path for circulating a refrigerant for cooling the motor, the motor is driven by a battery, and the battery is charged using the motor, the electric drive device has a flow regulating unit that regulates the flow rate of the refrigerant supplied to the rotor and the stator, and when the coil of the stator is energized to charge the battery while the vehicle is stopped, the flow regulating unit switches the flow rate of the refrigerant supplied to the rotor and the stator so that the flow rate of the refrigerant supplied to the stator increases compared to a case where the coil of the stator is not energized to charge the battery. Effects of the Invention

[0007] According to the present invention, it is possible to provide an electric drive device and a method for controlling the electric drive device that improve the reliability of a motor during rapid battery charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is an explanatory diagram of an electric drive device according to one embodiment of the present invention. Figure 2 yes Figure 1 The control process of the electric drive device. Figure 3 yes Figure 1 A variation of . Figure 4 This is a diagram illustrating the oil cooling surface in the motor during control according to one embodiment of the present invention. Figure 5 yes Figure 4 The control process of the electric drive device. DETAILED DESCRIPTION

[0009] The following description and drawings illustrate embodiments of the present invention. The following description and drawings are examples for illustrating the present invention and have been appropriately omitted or simplified for clarity. The present invention can also be implemented in various other forms. Unless otherwise specified, each component may be single or multiple.

[0010] To facilitate understanding of the invention, the positions, sizes, shapes, and ranges of the components shown in the drawings may not necessarily represent their actual positions, sizes, shapes, and ranges. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0011] (One embodiment and overall structure) ( Figure 1 ) The electric drive device 100 used in the present invention is provided in a vehicle such as an electric car and drives the motor 2 via a battery. However, when charging the battery, the motor 2 is used for charging in order to shorten the charging time while the vehicle is stopped. Specifically, the electric drive device 100 receives power from a charging device such as a commercial AC power supply while the vehicle is stopped, and charges the high-voltage battery mounted on the vehicle, thereby obtaining driving power for the vehicle. At this time, in order to charge the battery having a voltage higher than the voltage of the charging device, the electric drive device 100 uses a boost chopper circuit of the three-phase line of the motor 2 to boost the voltage. This makes it possible to quickly charge the battery while the vehicle is stopped. The boost chopper circuit is composed of, for example, a choke coil, a switching circuit, and a diode.

[0012] Furthermore, electric drive device 100 controls the flow of refrigerant through various electrical devices included in the vehicle. Inverter 1 and motor 2, which has a rotor 2c and a stator 2d, are cooled by refrigerant flow paths for cooling water 3a and cooling oil 3b. Cooling water 3a circulates through inverter 1 and motor 2, cooling them.

[0013] The cooling of the inverter 1 and motor 2 by cooling water 3a will be described. The EWP7 (Electric Water Pump) cools the inverter 1 by supplying cooling water 3a to the inverter 1. The cooling water 3a is then supplied from the inverter 1 to the motor 2, where it flows through a jacket 2a, for example, located on the outer periphery of the motor 2, cooling the entire motor 2.

[0014] Cooling water 3a, which has cooled motor 2, is supplied to heat exchanger 4, where it indirectly cools cooling oil 3b passing through heat exchanger 4. Cooling water 3a is then sent from heat exchanger 4 to radiator 6, where it is cooled by radiator 6, having absorbed heat from motor 2 and cooling oil 3b, to a temperature sufficient to adequately cool various components. From radiator 6, cooling water 3a is then sent to EWP 7. This completes the circulation cycle of cooling water 3a in the vehicle.

[0015] Next, we'll explain how cooling oil 3b cools motor 2. When performing rapid charging while the vehicle is stationary, a boost circuit using the motor's three-phase wires is utilized. However, this requires enhanced cooling of stator 2d, which has stator coils 2b that generate a large amount of heat. To achieve this, the refrigerant supply to rotor 2c is reduced, and this reduction is used to increase the refrigerant supply to stator 2d. This increased refrigerant supply to stator 2d enhances cooling of stator 2d.

[0016] The flow of the refrigerant of the specific cooling oil 3b will be described. The EOP5 (Electric Oil Pump) supplies the cooling oil 3b to the flow control unit 8 via the heat exchanger 4. For example, when it is determined that the vehicle has stopped and the battery has started rapid charging based on an instruction from a higher-level control device (not shown), the flow control unit 8 adjusts and switches the flow rate of the refrigerant supplied to the rotor 2c and stator 2d in the motor 2. Specifically, the flow control unit 8 switches the supply amount so that the supply amount of cooling oil 3b supplied to the rotor 2c via the shaft 9 is reduced, and the supply amount of cooling oil 3b to the stator 2d having the stator coil 2b is increased.

[0017] As a result, the refrigerant flow rate supplied to stator 2d, including the stator core and stator coil 2b, increases compared to when the battery is charged without energizing stator coil 2b. This allows for improved cooling of the stator, which generates increased heat during rapid charging, while the vehicle is stationary, in parallel with the voltage boost associated with charging the vehicle battery. Furthermore, stator coil 2b can be directly cooled by cooling oil 3b. Furthermore, burning of stator coil 2b can be prevented during rapid battery charging.

[0018] In addition, the flow switching of the cooling oil 3b to the rotor 2c and the stator 2d in the flow regulating unit 8 can be determined, for example, by a temperature sensor (not shown) that detects the temperature of the stator 2d of the motor 2. When the temperature is greater than a predetermined threshold value, or when it is determined to be exceeded based on a benchmark that predicts that the predetermined threshold value is exceeded, the flow switching of the cooling oil 3b supplied to the stator 2d is achieved by increasing the flow rate of the cooling oil 3b supplied to the stator 2d and reducing the flow rate of the cooling oil 3b supplied to the rotor 2c.

[0019] The cooling oil 3b that has cooled the rotor 2c and the stator 2d returns to the EOP 5. When the cooling oil 3b is supplied to the motor 2 again from the EOP 5, the heat of the cooling oil 3b is similarly released indirectly to the cooling water 3a passing through the heat exchanger 4, thereby returning the cooling oil 3b to a temperature that can appropriately cool the motor 2.

[0020] In addition, although the purpose is to cool the motor 2 in the first flow path through which the cooling water 3a flows and the second flow path through which the cooling oil 3b flows while using the heat exchanger 4 to cool the cooling oil 3b, the description is based on the premise that the first flow path through which the cooling water 3a flows is allowed to flow first, but this is not limited to this, and any one of the flow paths can also be allowed to flow first.

[0021] ( Figure 2 ) The flow of controlling the refrigerant flow rate of the electric drive device 100 of the present invention will be described. In step S1, it is determined whether the vehicle has started fast charging. If it is determined that fast charging has started, the process proceeds to step S2. If fast charging has not started, the process ends.

[0022] In step S2, with the start of fast charging, it is determined whether the stator coil 2b needs to be cooled. If it is determined that the stator coil 2b needs to be cooled during fast charging, the process proceeds to step S3. If not, the process ends.

[0023] In step S3 , the amount of cooling of the stator 2 d having the stator coil 2 b is increased in order to directly cool the stator coil 2 b using the cooling oil 3 b , and the process ends.

[0024] This not only increases the amount of cooling for the stator 2d during fast charging, but also reduces the amount of cooling for the rotor 2c, thereby suppressing unnecessary driving of the oil pump and water pump and thereby suppressing battery power consumption.

[0025] (Variation) ( Figure 3 ) The present invention can also be applied to the case where the motor 2 is cooled using only the cooling oil 3b instead of the cooling water 3a. In this case, the cooling water 3a cools the inverter 1 via the radiator 6 and the EWP 7, but does not pass through the motor 2, but circulates through other electrical devices (not shown) for cooling. On the other hand, the flow of the cooling oil 3b cooling the motor 2 is similar to that of the cooling oil 3b. Figure 1 Even in this case, since the cooling water 3a indirectly cools the cooling oil 3b via the heat exchanger 4, its temperature can be reduced to a level that can appropriately cool the motor 2. Therefore, even if the cooling water 3a is not circulated in the motor 2, sufficient cooling can be achieved, thereby preventing the stator coil 2b from burning during rapid charging.

[0026] In addition, when the motor 2 is cooled only by oil cooling with the cooling oil 3b, the circulation of the cooling oil 3b can be started after the circulation of the cooling water 3a to the heat exchanger 4 is started, or the circulation of the cooling water 3a can be started after the circulation of the cooling oil 3b is started, or they can be started simultaneously.

[0027] ( Figure 4 ) Figure 4 (a) is a radial cross-sectional view of the motor 2 showing the rise of the liquid level in the motor. Figure 4 (b) is Figure 4(a) is an axial cross-sectional view of the motor 2. In order to perform rapid charging, the vehicle is in a stopped state and the rotation of the rotor 2c has also stopped. If the rotor 2c is rotated when the cooling oil 3b is present in the motor 2, there is a risk that the cooling oil 3b will invade the gap between the stator 2d and the rotor 2c. Therefore, in order to prevent the cooling oil 3b from invading the gap portion, the vehicle has a structure that cuts off the power transmission so that the power used for driving is not transmitted to the driving shaft (drive shaft). As a result, the liquid level of the cooling oil 3b in the motor 2 can be safely raised, and the cooling oil 3b can be circulated in the motor 2 by the rotation of the rotor 2c after rapid charging, thereby promoting heat transfer between the cooling oil 3b, the rotor 2c and the stator 2d.

[0028] Flow regulating unit 8 ( Figure 1 ) If further cooling of the stator 2d is required, the stator 2d is oil-cooled, and the cooling oil 3b in direct contact with the stator coil 2b is increased from the liquid level 3c to the liquid level 3d. This improves the cooling efficiency of the stator 2d.

[0029] The stator coil 2b, which reaches a high temperature during rapid charging, is detected by, for example, a sensor (not shown). If the temperature change per unit time exceeds a predetermined threshold, it is determined that appropriate cooling is insufficient, and the liquid level of the cooling oil 3b within the motor 2 is increased. Thus, by increasing the liquid level within the motor 2, cooling of the motor 2 can be improved during rapid charging.

[0030] ( Figure 5 ) Regarding Figure 4 The control flow of the electric drive device 100 of the present invention will be described. In step S11, the electric drive device 100 determines whether the vehicle has started fast charging. If it is determined that fast charging has started, the process proceeds to step S12. If fast charging has not started, the process ends.

[0031] In step S12, it is determined whether the stator coil 2b needs to be cooled during fast charging. If so, the process proceeds to step S13. In step S13, the flow rate of cooling oil 3b supplied to the stator 2d is increased to directly cool the stator coil 2b.

[0032] In step S14, it is determined whether the liquid level of the cooling oil 3b in the motor 2 needs to be raised. If it is not necessary to raise the liquid level in the motor 2, the process ends. If it is determined that the liquid level in the motor 2 needs to be raised, the liquid level of the cooling oil 3b in the motor 2 is further raised in step S15, and the process ends.

[0033] In the above, in the present invention, the motor 2 and the inverter 1 are cooled by water cooling and oil cooling. However, the inverter 1 and the motor 2 may be cooled by water cooling alone.

[0034] According to the embodiment of the present invention described above, the following effects can be obtained.

[0035] (1) An electric drive device, in a vehicle having a motor 2 having a rotor 2c and a stator, and a refrigerant flow path through which refrigerant for cooling the motor 2 flows, drives the motor 2 via a battery and uses the motor 2 to charge the battery. The electric drive device includes a flow regulator 8 that regulates the flow rate of refrigerant supplied to the rotor 2c and the stator. When the stator coil 2b is energized to charge the battery while the vehicle is stopped, the flow regulator 8 switches the flow rate of refrigerant supplied to the rotor 2c and the stator so that the flow rate of refrigerant supplied to the stator is increased compared to when the stator coil 2b is not energized to charge the battery. Thus, an electric drive device 100 can be provided that improves the reliability of the motor 2 during rapid battery charging.

[0036] (2) A temperature sensor is provided to detect the stator temperature. When the stator temperature detected by the temperature sensor exceeds a predetermined threshold, the flow rate regulator 8 increases the flow rate of the refrigerant supplied to the stator. This prevents the stator coil 2b from burning out during rapid battery charging.

[0037] (3) A temperature sensor is provided to detect the stator temperature. When the stator temperature detected by the temperature sensor exceeds a predetermined threshold, the flow rate regulator 8 reduces the flow rate of the refrigerant supplied to the rotor 2c. This prevents burnout of the stator coil 2b during rapid battery charging.

[0038] (4) The flow rate regulator 8 switches the flow rate of the refrigerant supplied to the rotor 2c and the stator so that the refrigerant filling height in the motor 2 becomes higher. This allows for further cooling of the stator coil 2b.

[0039] (5) The refrigerant includes cooling water 3a and cooling oil 3b, and the cooling water 3a is circulated in the refrigerant flow path formed on the outer circumference of the stator. This can prevent the stator coil 2b from burning out, for example, when the motor 2 is cooled only by water cooling.

[0040] (6) The refrigerant includes cooling water 3a and cooling oil 3b, and includes a first flow path through which cooling water 3a flows to cool the motor 2 and electrical devices other than the motor 2, and a second flow path through which cooling oil 3b flows to cool the motor 2. In this case, either cooling water 3a flowing through the first flow path or cooling oil 3b flowing through the second flow path is prioritized. Consequently, regardless of which flow path is prioritized, both contribute to cooling the motor 2 during rapid charging.

[0041] (7) The refrigerant includes cooling water 3a and cooling oil 3b, and includes a first flow path through which cooling water 3a flows to cool the motor 2 and electrical devices other than the motor 2, and a second flow path through which cooling oil 3b flows to cool the motor 2. The cooling water 3a flowing through the first flow path is caused to flow before the cooling oil 3b flowing through the second flow path. This allows the second flow path to be used before the first flow path, thereby contributing to cooling of the motor 2 during rapid charging.

[0042] (8) A control method for an electric drive device, in a vehicle having a motor 2 having a rotor 2c and a stator cooled by a refrigerant, wherein the electric drive device uses a battery for both charging and driving the motor 2. When the stator coils are energized to charge the battery while the vehicle is stopped, the flow rate of the refrigerant supplied to the rotor 2c and the stator is switched so that the flow rate of the refrigerant supplied to the stator is increased compared to when the stator coils 2b are not energized to charge the battery. By adopting such a control method, the reliability of the motor 2 during rapid battery charging can be improved.

[0043] Furthermore, the present invention is not limited to the above-described embodiments, and various modifications and other configurations can be combined without departing from the spirit thereof. Explanation of symbols

[0044] 1 Inverter 2 motors 2a Jacket 2b Stator coil 2c rotor 2d stator 3 Refrigerant 3a Cooling water 3b Cooling oil 3c Liquid level 3d Liquid level after rising 4 Heat exchanger 5 EOP 6 Radiator 7 EWP 8 Flow regulation unit 9-axis 100 Electric drive unit.

Claims

1. An electric drive device, in a vehicle including a motor having a rotor and a stator, and a refrigerant flow path through which a refrigerant for cooling the motor flows, wherein the electric drive device drives the motor using a battery and charges the battery using the motor, wherein: A flow rate regulating unit is provided for regulating the flow rate of the refrigerant supplied to the rotor and the stator. When the coil of the stator is energized to charge the battery while the vehicle is stopped, the flow regulating unit switches the flow rate of the refrigerant supplied to the rotor and the stator so that the flow rate of the refrigerant supplied to the stator increases compared to a case where the battery is charged without energizing the coil of the stator.

2. The electric drive device according to claim 1, characterized in that A temperature sensor is provided to detect the temperature of the stator. The flow rate regulator increases the flow rate of the refrigerant supplied to the stator when the temperature of the stator detected by the temperature sensor is greater than a predetermined threshold value.

3. The electric drive device according to claim 1, characterized in that A temperature sensor is provided to detect the temperature of the stator. The flow rate regulator reduces the flow rate of the refrigerant supplied to the rotor when the temperature of the stator detected by the temperature sensor is greater than a predetermined threshold value.

4. The electric drive device according to claim 1, characterized in that The flow rate adjustment unit switches the flow rate of the refrigerant supplied to the rotor and the stator so that the filling height of the refrigerant in the motor becomes higher.

5. The electric drive device according to claim 1, characterized in that The refrigerant includes cooling water and cooling oil, The cooling water is caused to flow through a refrigerant flow path formed on the outer peripheral side of the stator.

6. The electric drive device according to claim 1, characterized in that The refrigerant includes cooling water and cooling oil, The device comprises a first flow path through which the cooling water for cooling the motor and electrical devices other than the motor flows, and a second flow path through which the cooling oil for cooling the motor flows, Either the cooling water flowing through the first flow path or the cooling oil flowing through the second flow path is caused to flow first.

7. The electric drive device according to claim 1, characterized in that The refrigerant includes cooling water and cooling oil, The device includes a first flow path through which the cooling water for cooling the motor and electrical devices other than the motor flows, and a second flow path through which the cooling oil for cooling the motor flows. The cooling water flowing through the first flow path is caused to flow prior to the cooling oil flowing through the second flow path.

8. A method for controlling an electric drive device in a vehicle having an electric motor having a rotor and a stator cooled by a refrigerant, the electric drive device using a battery for both charging and driving the electric motor, the method comprising: When the coil of the stator is energized to charge the battery while the vehicle is stopped, the flow rate of the refrigerant supplied to the rotor and the stator is switched so that the flow rate of the refrigerant supplied to the stator is increased compared to when the battery is charged without energizing the coil of the stator.

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