JP2017118661A - Insulation structure for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation structure for an electric vehicle that prevents insulation breakdown without being limited by output even at a high altitude.SOLUTION: An insulation structure for an electric vehicle that prevents insulation breakdown of at least a rotary electric machine mounted in an electric vehicle, comprises: a sealed case 3a holding pressure in the rotary electric machine 3; a sealed case 4a holding pressure in an inverter 4; pressure sensors 32A, 32B that detect pressure in the sealed case; an atmospheric pressure sensor 33 that detects atmospheric pressure; pressure adjustment valves 31A, 31B that switch sealing of the sealed case and communication with atmosphere; and a pressure control part 30 that controls a pressure adjustment valve. A pressure control part exerts control such that if pressure in the sealed case is equal to or higher than atmospheric pressure, the pressure adjustment valve is closed, and if pressure in the sealed case is lower than atmospheric pressure, the pressure adjustment value is opened.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an insulating structure for an electric vehicle equipped with a traveling motor (electric motor) as a drive source.

  2. Description of the Related Art Conventionally, an electric vehicle such as an electric vehicle or a hybrid vehicle includes a travel motor as a drive source. A structure in which a pressure adjusting valve for adjusting the pressure in the case body is provided in the case body that accommodates such a motor or inverter is known. In such a structure, when the vehicle moves to a place with a high altitude, the pressure inside the case body decreases. In general, it is known that in the normal range of the voltage applied to the motor, the dielectric strength decreases as the pressure decreases. When the pressure in the case body decreases, the voltage applied to the motor must be decreased to avoid dielectric breakdown, resulting in a decrease in the output of the motor.

  Therefore, conventionally, since the insulation resistance of a motor or the like is lowered at a high altitude, it has been proposed to control the application of voltage to the motor (see Patent Document 1). Also, with such control, output is limited at high altitudes, so when a high altitude is detected, air is supplied into the motor case body by the compressor to suppress pressure drop. Has been proposed (see Patent Document 2).

JP 2014-50174 A JP 2009-278849 A

  However, in patent document 2, since air is always supplied according to the altitude, there is a problem that air may be supplied wastefully inside the case body of the motor.

  This invention is made | formed in view of such a situation, and it aims at providing the insulation structure of the electric vehicle which can prevent a dielectric breakdown, without receiving the restriction | limiting of an output, even when an altitude is high. .

  A first aspect of the present invention that solves the above problem is an insulating structure for an electric vehicle that prevents breakdown of at least the rotating electric machine mounted on the electric vehicle, and a sealed case that holds the pressure inside the rotating electric machine. A pressure sensor that detects pressure in the sealed case, an atmospheric pressure sensor that detects the atmospheric pressure, a pressure adjustment valve that switches between a sealed state of the sealed case and a communication state with the atmosphere, and the pressure control valve A pressure control unit for controlling the pressure control unit, the pressure control unit closes the pressure regulating valve when the pressure inside the sealed case is equal to or higher than the atmospheric pressure, and the pressure inside the sealed case is When the pressure is lower than the atmospheric pressure, the control is performed so that the pressure regulating valve is opened.

  In such an embodiment, the case of the rotating electrical machine has a sealed structure, the pressure adjustment valve is closed when the pressure inside the sealed case is equal to or higher than atmospheric pressure, and the pressure adjustment is performed when the pressure inside the sealed case is lower than atmospheric pressure. By controlling the valve to be open, it is possible to prevent dielectric breakdown without being affected by an external change in atmospheric pressure, and to control to a desired target voltage.

  According to a second aspect of the present invention, in the insulating structure for an electric vehicle according to the first aspect, the inverter connected to the rotating electrical machine includes a second sealed case, and the sealed state of the second sealed case and the atmosphere. A second pressure regulating valve that switches between a state of communication with the second pressure regulating valve, and the pressure control unit controls the second pressure regulating valve when the pressure inside the second sealed case is equal to or higher than the atmospheric pressure. In the insulating structure of the electric vehicle, the second pressure regulating valve is controlled to be opened when the pressure inside the sealed case of the rotating electrical machine is lower than the atmospheric pressure. .

  In such an aspect, the inverter case has a sealed structure, and when the pressure inside the second sealed case is equal to or higher than the atmospheric pressure, the second pressure regulating valve is closed, and the pressure inside the second sealed case is high. By controlling the second pressure regulating valve to open when the pressure is lower than the atmospheric pressure, it is possible to prevent dielectric breakdown without being influenced by an external atmospheric pressure change, and to control to a desired target voltage. Can do.

  According to a third aspect of the present invention, in the insulating structure for an electric vehicle according to the first or second aspect, the pressure control unit is configured such that the pressure inside the sealed case exceeds a second predetermined pressure higher than 1 atm. Controlling to open the pressure regulating valve, and controlling to open the second pressure regulating valve when the pressure inside the second sealed case exceeds the second predetermined pressure. An insulating structure for an electric vehicle characterized by the above.

  In such an aspect, when the internal pressure of the rotating electrical machine or the like rises beyond the second predetermined voltage due to high load operation of the vehicle, the pressure adjustment valve can be opened and adjusted to an appropriate pressure.

  According to a fourth aspect of the present invention, in the insulating structure for an electric vehicle according to any one of the first to third aspects, the pressure control unit has a first internal pressure lower than 1 atm. In such a case, the electric vehicle is controlled so as to limit the target voltage required by the electric vehicle to a low level.

  In such an aspect, if the pressure inside the sealed case is equal to or lower than the first predetermined pressure lower than 1 atm, the dielectric breakdown can be prevented by limiting the target voltage required by the vehicle to be low. .

  According to the insulating structure of the electric vehicle of the present invention, the case of the rotating electrical machine is sealed, and when the pressure inside the sealed case is equal to or higher than the atmospheric pressure, the pressure adjustment valve is closed, and the pressure inside the sealed case is reduced. By controlling the pressure regulating valve to open when the pressure is lower than the atmospheric pressure, it is possible to prevent dielectric breakdown without being influenced by an external pressure change, and to control to a desired target voltage. There is an effect.

It is a figure showing the schematic structure of the electric vehicle concerning one embodiment of the present invention. It is a block diagram showing a schematic structure of an insulating structure concerning one embodiment of the present invention. It is a flowchart which shows an example of control of the insulation structure concerning this invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
First, the overall configuration of the electric vehicle according to the present embodiment will be described. As shown in FIG. 1, an electric vehicle 1 according to the present embodiment is an electric vehicle (EV), which is a battery 2 that is a secondary battery, and a rotating electric machine as a drive source that is operated by electric power of the battery 2. A traveling motor (electric motor) 3. The battery 2 and the traveling motor 3 are connected via an inverter 4. The traveling motor 3 is connected to driving wheels (in this embodiment, front wheels) 6 via a transmission system 5 including an automatic transmission (not shown), for example.

  The travel motor 3 drives the drive wheels 6 via the transmission system 5 during normal travel, while generating power by receiving rotation from the drive wheels 6 during so-called regeneration and supplying the power to the battery 2. . That is, the traveling motor 3 outputs a positive torque during normal traveling, and outputs a negative torque during regeneration.

  The electric vehicle 1 includes a control unit 10 that comprehensively controls the electric vehicle 1. For example, the traveling motor 3 is controlled by a motor control unit 20 provided in the control unit 10. The motor control unit 20 includes various sensors provided in the electric vehicle 1, for example, a brake pedal stroke sensor 22 that detects a stroke (BPS) of the brake pedal 21, a vehicle speed sensor 23 that detects a vehicle speed of the electric vehicle 1, and an electric vehicle. Output torque output from the traveling motor 3 by controlling the inverter 4 based on signals from the acceleration sensor 24 that detects the acceleration (deceleration) 1 and the torque sensor 25 that detects the output torque of the traveling motor 3. To be the right size.

  FIG. 2 shows a schematic configuration of an insulating structure mounted on such an electric vehicle. As shown in FIG. 2, the insulation structure of the present embodiment is applied to a traveling motor 3 and an inverter 4 that are rotating electrical machines, and a pressure control unit 30 is provided in the control unit 10 (see FIG. 1). ing.

  Each of the traveling motor 3 and the case 3a, 4a of the inverter 4 is provided with a sealed case 3b, 4b outside the case 3a, 4a, and a pressure regulating valve 31A for adjusting the pressure inside the sealed case 3b, 4b. , 31B, and pressure sensors 32A, 32B for detecting the pressure inside the sealed cases 3b, 4b, that is, inside the cases 3a, 3b. Further, the pressure control valves 31A and 31B are controlled by the pressure control unit 30, and the pressures detected by the pressure sensors 32A and 32B are transmitted to the pressure control unit 30.

  In this embodiment, air is supplied to the traveling motor 3 and the inverter 4 as a target for preventing dielectric breakdown. However, for example, the inverter 4 is provided with other countermeasures for dielectric breakdown so that only the traveling motor 3 is provided. The insulating structure of the present invention may be applied. In this embodiment, the pressure regulating valves 31A and 31B and the pressure sensors 32A and 32B are provided in the cases 3a and 4a of the traveling motor 3 and the inverter 4, respectively, but a sealed case including the cases 3a and 4a is provided. The adjustment and detection of the internal pressures of both may be performed by a single pressure sensor and pressure adjusting valve.

  Further, the sealed cases 3b and 4b are those having a sealing property to such an extent that the internal pressure is not substantially changed under the influence of the outside air when the pressure regulating valves 31A and 31B are closed. There is no need to provide the case 3a, 4a outside. In FIG. 2, for the sake of clarity, the sealed cases 3b and 4b are illustrated outside the cases 3a and 4a. However, the sealed cases 3b and 4b are improved by improving the sealing performance of the cases 3a and 4a. It is good.

  Next, an example of the control of the insulating structure of this embodiment will be described with reference to the flowchart of FIG. First, in step S1, it is determined whether or not the pressures of the pressure sensors 32A and 32B are higher than the second predetermined pressure B. If any of the pressures is higher than the second predetermined pressure B (step S1; Yes), the pressure The regulating valves 31A and 31B are opened (step S2), and the internal 9 pressure is prevented from excessively rising. On the other hand, if any of the pressures is equal to or lower than the second predetermined pressure B (step S1; No), the process proceeds to step S3.

  In step S3, it is determined whether or not the pressures of the pressure sensors 32A and 32B are equal to or higher than the output of the atmospheric pressure sensor 33. If any of the pressures is equal to or higher than the atmospheric pressure (step S3; Yes), the pressure regulating valves 31A and 31B. Is closed (step S4), and the internal pressure is prevented from lowering due to the atmospheric pressure. On the other hand, when the pressure of the pressure sensors 32A and 32B is lower than the atmospheric pressure (step S3; No), the process proceeds to step S5.

  In step S5, it is determined whether or not the pressure of the pressure sensors 32A and 32B is equal to or higher than a first predetermined pressure A lower than atmospheric pressure. If any of the pressures is equal to or higher than the first predetermined pressure A (step S5; Yes), The pressure regulating valves 31A and 31B are opened (step S6) so that the internal pressure returns to the original due to the influence of atmospheric pressure. On the other hand, when the pressures of the pressure sensors 32A and 32B are lower than the first predetermined pressure A (step S5; No), the dielectric breakdown is likely to occur. When there is a request for a high target voltage that causes a problem in insulation, the voltage is limited to a low voltage (step S7). Thereby, even when the pressure in the sealed cases 3b and 4b is lowered, it is possible to control so that dielectric breakdown does not occur.

  Here, the first predetermined pressure A is a pressure lower than 1 atm, and is an atmospheric pressure that may cause dielectric breakdown when the target voltage exceeds the predetermined voltage. For example, a pressure corresponding to an atmospheric pressure of about 3000 m may be used, but for safety, for example, a pressure corresponding to an atmospheric pressure of about 2000 m or about 1500 m may be used. For example, it is about 0.7 to 0.9 atm, preferably about 0.75 to 0.85 atm.

  On the other hand, the second predetermined pressure B is a pressure higher than 1 atm, and if it is higher than that, there is no meaning from the viewpoint of preventing dielectric breakdown, or if it is higher than that, the safety of the sealed cases 3b and 4b is ensured. What is necessary is just to set the pressure which cannot. For example, it is about 1.1 to 1.3 atm, preferably about 1.2 atm.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment.

  For example, in the above-described embodiment, the present invention has been described by exemplifying an electric vehicle (EV) including a traveling motor as an example of the electric vehicle. However, the present invention can be applied to various electric vehicles. For example, the present invention can also be applied to a hybrid vehicle that includes an engine (internal combustion engine) as a driving device together with a traveling motor.

DESCRIPTION OF SYMBOLS 1 Electric vehicle 2 Battery 3 Driving motor 4 Inverter 5 Transmission system 6 Drive wheel 10 Control part 20 Motor control part 21 Brake pedal 22 Brake pedal stroke sensor 23 Vehicle speed sensor 24 Acceleration sensor 25 Torque sensor 30 Pressure control part 31A, 31B Pressure adjustment Valve 32A, 32B Pressure sensor 33 Atmospheric pressure sensor

Claims (4)

An insulating structure of an electric vehicle that prevents dielectric breakdown of at least the rotating electric machine mounted on the electric vehicle,
A sealed case that holds the pressure inside the rotating electrical machine;
A pressure sensor for detecting the pressure in the sealed case;
An atmospheric pressure sensor for detecting the atmospheric pressure;
A pressure regulating valve for switching between a sealed state of the sealed case and a communication state with the atmosphere;
A pressure control unit for controlling the pressure regulating valve;
The pressure control unit closes the pressure regulating valve when the pressure inside the sealed case is equal to or higher than the atmospheric pressure, and closes the pressure regulating valve when the pressure inside the sealed case is lower than the atmospheric pressure. An insulating structure for an electric vehicle, characterized by being controlled to open. In the insulating structure of the electric vehicle according to claim 1,
An inverter connected to the rotating electrical machine has a second sealed case and a second pressure regulating valve for switching between a sealed state of the second sealed case and a communication state with the atmosphere;
The pressure control unit closes the second pressure regulating valve when the pressure inside the second sealed case is equal to or higher than the atmospheric pressure, and the pressure inside the sealed case of the rotating electrical machine is the high pressure. An insulating structure for an electric vehicle, wherein the second pressure regulating valve is controlled to be opened when the pressure is lower than the atmospheric pressure. In the insulation structure of the electric vehicle according to claim 1 or 2,
The pressure control unit controls to open the pressure regulating valve when the pressure inside the sealed case exceeds a second predetermined pressure higher than 1 atmosphere, and the pressure inside the second sealed case An insulating structure for an electric vehicle, wherein the second pressure regulating valve is controlled to open when the pressure exceeds the second predetermined pressure. In the insulating structure of the electric vehicle according to any one of claims 1 to 3,
The pressure control unit controls the target voltage required by the electric vehicle to be limited to a low level when the pressure inside the sealed case is equal to or lower than a first predetermined pressure lower than 1 atm. Electric vehicle insulation structure.

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