JP2015084614A - Vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress decrease of a power performance and to protect a motor.SOLUTION: When an air pressure Pm is equal to or more than a predetermined air pressure Pref, a boost voltage of a step-up converter 55 is not limited (steps S100, S120). When the air pressure Pm is less than the predetermined air pressure Pref and at least one of temperatures Tm1, Tm2 of motors MG1, MG2 is equal to or more than a predetermined temperature tref, a boost voltage is so limited to be larger than that in the case that the air pressure Pm is less than the predetermined air pressure Pref and the temperatures Tm1, Tm2 of both the motors MG1, MG2 are less than the predetermined temperature tref (steps S110, S130, S140). Consequently, decrease of a power performance can be suppressed and the motors MG1, MG2 can be protected.

Description

  The present invention relates to a vehicle, and more particularly, to a vehicle including a motor, a battery, and a boost converter provided between the motor and the battery.

  Conventionally, this type of vehicle includes a drive motor, a battery, and a boost converter provided between the drive motor and the battery. When the atmospheric pressure detection value is less than a predetermined threshold, the atmospheric pressure detection value is There has been proposed one that controls the boost converter so that the converter voltage allowable value becomes smaller as the voltage decreases and the voltage boosted by the boost converter becomes equal to or lower than the converter voltage allowable value (for example, Patent Document) 1). In this vehicle, by such control, when the atmospheric pressure detection value is less than a predetermined threshold value, it is possible to perform power limit control of the drive motor, and to suppress the temperature increase of the drive motor.

JP 2010-252572 A

  Generally, in a vehicle including a drive motor, a battery, and a boost converter provided between the drive motor and the battery, the surge voltage generated between the field winding conductors of the drive motor increases as the temperature of the drive motor increases. Therefore, it is desirable to limit the boost voltage of the boost converter as the temperature of the drive motor increases. However, if the boosted voltage is uniformly limited when the temperature of the drive motor is high, the power performance may deteriorate due to excessive limitation. For example, when the atmospheric pressure is high and the surge withstand voltage is sufficient, the boost voltage of the boost converter may not be limited. Therefore, it is desirable to protect the drive motor while suppressing a decrease in power performance of the vehicle by appropriately operating the boost converter in consideration of the atmospheric pressure and the temperature of the drive motor.

  The main object of the vehicle of the present invention is to protect the motor while suppressing a decrease in power performance.

  The vehicle of the present invention employs the following means in order to achieve the main object described above.

The vehicle of the present invention
A vehicle comprising a motor, a battery, and a boost converter provided between the motor and the battery,
When the atmospheric pressure is equal to or higher than a predetermined atmospheric pressure, the boosting voltage of the boost converter is not limited, and when the atmospheric pressure is lower than the predetermined atmospheric pressure, limiting means for limiting the boosted voltage,
When the atmospheric pressure is lower than the predetermined atmospheric pressure and the temperature of the motor is equal to or higher than the predetermined temperature, the control means is more effective than when the atmospheric pressure is lower than the predetermined atmospheric pressure and the temperature of the motor is lower than the predetermined temperature. The gist is that it is a means of greatly limiting the boost voltage.

  In the vehicle according to the present invention, the boosted voltage of the boost converter is not limited when the atmospheric pressure is equal to or higher than the predetermined atmospheric pressure, and the boosted voltage is limited when the atmospheric pressure is lower than the predetermined atmospheric pressure. When the atmospheric pressure is equal to or higher than the predetermined atmospheric pressure, a reduction in power performance can be suppressed by not limiting the boosted voltage. Moreover, since the surge withstand voltage is low when the atmospheric pressure is less than the predetermined atmospheric pressure, the motor can be protected by limiting the boosted voltage. When the atmospheric pressure is lower than the predetermined atmospheric pressure and the motor temperature is equal to or higher than the predetermined temperature, the boosted voltage is limited to a greater degree than when the atmospheric pressure is lower than the predetermined atmospheric pressure and the motor temperature is lower than the predetermined temperature. When the motor temperature is equal to or higher than the predetermined temperature, the surge voltage becomes larger than when the motor temperature is lower than the predetermined temperature. Therefore, when the atmospheric pressure is lower than the predetermined atmospheric pressure and the motor temperature is equal to or higher than the predetermined temperature, the atmospheric pressure is equal to the predetermined atmospheric pressure. When the motor temperature is equal to or higher than the predetermined temperature, the motor can be protected when the temperature of the motor is equal to or higher than the predetermined temperature. When the temperature is lower than the predetermined temperature, a decrease in power performance can be suppressed. As a result, it is possible to protect the motor while suppressing a decrease in power performance. Here, the “predetermined atmospheric pressure” is a predetermined lower limit value of the atmospheric pressure at which the motor is unlikely to cause dielectric breakdown, and the “predetermined temperature” is a motor that is highly likely to cause dielectric breakdown. It is assumed that the lower limit of the temperature is predetermined.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. 5 is a flowchart showing an example of a boost converter control routine executed by an HVECU 70. It is explanatory drawing which shows an example of the map for VH limiting voltage setting.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention. As shown in FIG. 1, the hybrid vehicle 20 of the embodiment includes an engine 22 that outputs power using gasoline, light oil, or the like as a fuel, and an engine electronic control unit (hereinafter referred to as an engine ECU) 24 that drives and controls the engine 22. A single pinion planetary gear 30 in which a carrier is connected to the crankshaft 26 of the engine 22 and a ring gear is connected to a drive shaft 36 connected to drive wheels 38a and 38b via a differential gear 37; For example, a motor MG1 whose rotor is connected to the sun gear of the planetary gear 30, a motor MG2 which is configured as a synchronous generator motor and whose rotor is connected to the drive shaft 36, and for driving the motors MG1 and MG2. Inverters 41 and 42 and inverters 41 and 42 A motor electronic control unit (hereinafter referred to as a motor ECU) 40 that drives and controls the motors MG1 and MG2 by switching control of a switching element (not shown), and a lithium ion secondary battery, for example, are connected via inverters 41 and 42. HV battery 50 that exchanges power with motors MG1 and MG2, a power line (hereinafter referred to as a high voltage system power line) 54a to which inverters 41 and 42 are connected, and a power line (hereinafter referred to as a battery voltage) to which HV battery 50 is connected. A boost converter 55 connected to the system power line 54b, and a high-voltage electronic device (for example, an electric water attached to the cooling system of the engine 22 and the motors MG1 and MG2) attached to the high-voltage system power line 54a. 57) and battery voltage system power line 5 The air conditioner (A / C) 60 attached to b, the auxiliary battery 66 having a voltage lower than that of the HV battery 50, for example, configured as a lead storage battery, the battery voltage system power line 54b, and the auxiliary battery 66 are connected. A DC / DC converter 64 connected to a power line (hereinafter referred to as a low voltage system power line) 54c to step down the power of the battery voltage system power line 54b and supply it to the low voltage system power line 54c; and a low voltage system power line An electric power steering (EPS) 67 and an electronically controlled brake system (ECB) 68 connected to 54c and supplied with electric power from an auxiliary battery 66, and an electronic control unit for battery (hereinafter referred to as a battery ECU) for managing the HV battery 50 52, and a hybrid electronic control unit (hereinafter referred to as HVECU) 70 for controlling the entire vehicle, Is provided.

  Boost converter 55 is connected to battery voltage system power line 54b via system main relay 56, and voltage VH of high voltage system power line 54a is in a range not less than voltage VL of battery voltage system power line 54b and not more than maximum allowable voltage VHmax. The power is exchanged between the high voltage system power line 54a and the battery voltage system power line 54b.

  Although not shown, the engine ECU 24 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . Signals from various sensors that detect the state of the engine 22 are input to the engine ECU 24 via an input port. Further, various control signals for driving the engine 22 are output from the engine ECU 24 via an output port. The engine ECU 24 communicates with the HVECU 70, controls the operation of the engine 22 by a control signal from the HVECU 70, and outputs data related to the operating state of the engine 22 as necessary.

  Although not shown, the motor ECU 40 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The motor ECU 40 receives input of motor temperatures tm1 and tm2 from temperature sensors 43 and 44 for detecting the temperatures of the motors MG1 and MG2 and signals necessary for driving and controlling the motors MG1 and MG2 via an input port. . The motor ECU 40 outputs a switching control signal to a switching element (not shown) of the inverters 41 and 42 through an output port. The motor ECU 40 is in communication with the HVECU 70, controls the driving of the motors MG1 and MG2 by a control signal from the HVECU 70, and outputs data related to the operating state of the motors MG1 and MG2 to the HVECU 70 as necessary.

  Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The battery ECU 52 includes a signal necessary for managing the HV battery 50, for example, an inter-terminal voltage Vb from a voltage sensor installed between terminals of the HV battery 50 and an electric power line connected to an output terminal of the HV battery 50. The charging / discharging current Ib from the current sensor attached to the HV battery 50 is input, and data on the state of the HV battery 50 is transmitted to the HVECU 70 by communication as necessary. Further, in order to manage the HV battery 50, the battery ECU 52 is based on the integrated value of the charge / discharge current Ib detected by the current sensor, and the ratio of the capacity of the electric power that can be discharged from the HV battery 50 at that time to the total capacity. A certain storage ratio SOC is calculated.

  Although not shown, the HVECU 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. The HVECU 70 includes an ignition signal from the ignition switch 80, a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator opening degree from the accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83. Acc, the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, the atmospheric pressure Pm from the atmospheric pressure sensor 90, and the inter-terminal voltage of the auxiliary battery 66 are detected. The auxiliary battery voltage Vbl from the voltage sensor is input via the input port. Further, as described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52.

  In the hybrid vehicle 20 of the embodiment configured in this way, the required torque Tr * required for traveling is set based on the accelerator opening Acc and the vehicle speed V corresponding to the depression amount of the accelerator pedal by the driver, and the set request Multiply the torque Tr * by the rotational speed Nr of the drive shaft 36 (for example, the rotational speed Nm2 of the motor MG2 or the rotational speed obtained by multiplying the vehicle speed V by the conversion factor) to calculate the traveling power Pdrv * required for traveling. Demand required for the vehicle by subtracting the charge / discharge required power Pb * of the HV battery 50 (a positive value when discharging from the HV battery 50) from the calculated travel power Pdrv * based on the storage ratio SOC of the HV battery 50 Set the power Pe *. The target rotational speed Ne *, the target torque Te *, and the torque commands Tm1 * of the motors MG1, MG2 are output so that the required power Pe * is output from the engine 22 and the required torque Tr * is output to the drive shaft 36. , Tm2 *.

  When the target rotational speed Ne *, the target torque Te *, and the torque commands Tm1 *, Tm2 * of the motors MG1, MG2 are thus set, the target rotational speed Ne * and the target torque Te * for the engine 22 are set. Thus, the intake air amount control, the fuel injection control, the ignition control, and the like of the engine 22 are performed so that the engine 22 is operated. Then, using the boost voltage VHc based on the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 and the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2, the target voltage VH * (by the boost converter 55) The target value of the boosted voltage) is set, and the switching element of the boost converter 55 is controlled to be switched to the voltage VH of the high voltage system power line 54a so that the voltage VH of the high voltage system power line 54a becomes the target voltage VH *. On the other hand, switching control of the switching elements of inverters 41 and 42 is performed so that motors MG1 and MG2 are driven by torque commands Tm1 * and Tm2 * within a range of torque that can be output from motors MG1 and MG2.

  Here, an operation when controlling boost converter 55 will be described. FIG. 2 is a flowchart showing an example of a boost converter control routine executed by the HVECU 70.

  When this routine is executed, the HVECU 70 executes a process of comparing the atmospheric pressure Pm detected by the atmospheric pressure sensor 90 with the predetermined atmospheric pressure Pref (step S100). Here, the predetermined atmospheric pressure Pref is a value determined in advance as a lower limit value of the atmospheric pressure (eg, 90 [ kPa] etc.).

  When the atmospheric pressure Pm is equal to or higher than the predetermined atmospheric pressure Pref (step S100), it is determined that there is no need to limit the boost voltage by the boost converter 55 to protect the motors MG1 and MG2 because the surge withstand voltages of the motors MG1 and MG2 are sufficiently high. The boost voltage VHc based on the torque commands Tm1 *, Tm2 * of the motors MG1, MG2 and the rotation speeds Nm1, Nm2 of the motors MG1, MG2 is set to the target voltage VH * without limiting the boost voltage VHc. Switching control of the switching element of the boost converter 55 is performed so that the voltage VH of the voltage system power line 54a becomes the target voltage VH * (step S120). By such control, the motors MG1 and MG2 can be driven by the torque commands Tm1 * and Tm2 *, and a decrease in power performance can be suppressed.

  When the atmospheric pressure Pm is less than the predetermined atmospheric pressure Pref (step S100), it is determined that the surge withstand voltage of the motors MG1 and MG2 is low and the boosted voltage by the boost converter 55 needs to be limited to protect the motors MG1 and MG2. Subsequently, the motor temperatures tm1, tm2 input from the motor ECU 40 are compared with the predetermined temperature tref (step S120). Here, the predetermined temperature tref is assumed to be a predetermined value (for example, 170 [° C.]) as a lower limit value of the motor temperature at which the motors MG1 and MG2 are likely to cause dielectric breakdown.

  When at least one of the motor temperatures tm1 and tm2 is equal to or higher than the predetermined temperature tref (step S120), the motor water temperature normal line of the VH limit voltage setting map is used to drive the motor to the boost voltage VHc based on the atmospheric pressure Pm. A VH limit voltage Vmax for protecting MG1 and MG2 is set, and the target voltage VH * of the high voltage system power line 54a is set as a voltage obtained by limiting the boost voltage VHc with the VH limit voltage Vmax (the boost voltage VHc and the VH limit). The lower one of the voltages Vmax is set as the target voltage VH *), the boost converter 55 is controlled so that the voltage VH of the high voltage system power line 54a becomes the target voltage VH * (step S130), and the motor temperature tm1 , Tm2 are both lower than the predetermined temperature tref (step S120), the VH limit voltage A VH limit voltage Vmax for protecting the motors MG1 and MG2 is set for the boost voltage VHc based on the atmospheric pressure Pm using the motor water temperature low temperature line of the setting map, and the boost voltage VHc is set to the VH limit voltage Vmax. The target voltage VH * of the high voltage system power line 54a is set as the voltage limited in step (the lower voltage of the boost voltage VHc and the VH limit voltage Vmax is set as the target voltage VH *), and the high voltage system power line The boost converter 55 is controlled so that the voltage VH of 54a becomes the target voltage VH * (step S140), and this routine is finished.

  FIG. 3 is an explanatory diagram showing an example of a VH limit voltage setting map. In the figure, the motor water temperature normal line is used when at least one of the motor temperatures tm1 and tm2 is equal to or higher than the predetermined temperature tref, and the motor water temperature low temperature line is such that both the motor temperatures tm1 and tm2 are the predetermined temperature. It was used when it was less than tref. As shown in the figure, the VH limit voltage Vmax is set such that the lower the atmospheric pressure Pm (for example, the higher the altitude), the lower (the boost voltage is greatly limited). The VH limit voltage Vmax is greater when at least one of the motor temperatures tm1 and tm2 is equal to or higher than the predetermined temperature tref than when the motor temperatures tm1 and tm2 are both lower than the predetermined temperature tref (line for motor water temperature low temperature). In the normal line), the VH limit voltage Vmax is set to be lower (the boost voltage is largely limited). Generally, when the motor temperature is high, the surge voltage is larger than when the motor temperature is low. Therefore, at least one of the motor temperatures tm1 and tm2 is higher than when both the motor temperatures tm1 and tm2 are lower than a predetermined temperature tref. When the temperature of the motors MG1 and MG2 is high by lowering the VH limit voltage Vmax and greatly limiting the boost voltage of the boost converter 55 when the temperature of the motors MG1 and MG2 is high. MG2 can be protected, and when the temperatures of the motors MG1 and MG2 are low, a decrease in power performance can be suppressed.

  According to the hybrid vehicle 20 of the embodiment described above, the boosted voltage of the boost converter 55 is not limited when the atmospheric pressure Pm is equal to or higher than the predetermined atmospheric pressure Pref, and the boosted voltage is limited when the atmospheric pressure Pm is less than the predetermined atmospheric pressure Pref. Since the boosted voltage is not limited when the atmospheric pressure Pm is equal to or higher than the predetermined atmospheric pressure Pref, it is possible to suppress a decrease in power performance and to protect the motors MG1 and MG2 when the atmospheric pressure is lower than the predetermined atmospheric pressure Pref. . When the atmospheric pressure Pm is lower than the predetermined atmospheric pressure Pref and at least one of the temperatures Tm1 and Tm2 of the motors MG1 and MG2 is equal to or higher than the predetermined temperature tref, the atmospheric pressure Pm is lower than the predetermined atmospheric pressure Pref and both the motors MG1 and MG2 Since the boosted voltage is limited more than when the temperatures Tm1 and Tm2 are lower than the predetermined temperature tref, the motors MG1 and MG2 can be protected when the temperatures of the motors MG1 and MG2 are equal to or higher than the predetermined temperature tref. When the temperatures of the motors MG1 and MG2 are lower than the predetermined temperature tref, it is possible to suppress a decrease in power performance. As a result, it is possible to protect the motors MG1 and MG2 while suppressing a decrease in power performance.

  In the hybrid vehicle 20 of the embodiment, the motor temperatures tm1, tm2 and the predetermined temperature tref are compared in the process of step S120, but only the motor temperature tm2 and the predetermined temperature tref may be compared.

  In the hybrid vehicle 20 of the embodiment, when at least one of the motor temperatures tm1 and tm2 is equal to or higher than the predetermined temperature tref, the VH limit voltage Vmax is set using the motor water temperature normal line in the VH limit voltage setting map. When both the temperatures tm1 and tm2 are lower than the predetermined temperature tref, the VH limit voltage Vmax is set using the motor water temperature low temperature line in the VH limit voltage setting map. However, both the motor temperatures tm1 and tm2 are set. Is set at a predetermined temperature tref or higher, the VH limit voltage Vmax is set using the motor water temperature normal line of the VH limit voltage setting map, and when at least one of the motor temperatures tm1 and tm2 is lower than the predetermined temperature tref, VH limit voltage Vmax is set using the motor water temperature low temperature line in the VH limit voltage setting map It may be as shall.

  In the embodiment, the present invention is applied to the engine 22, the motor MG 1, and the drive shaft 36 connected to the drive wheels 38 a and 38 b via the differential gear 37 while the carrier is connected to the crankshaft 26 of the engine 22. The present invention is applied to a vehicle including planetary gear 30 connected, motor MG1 having a rotor connected to the sun gear of planetary gear 30, and motor MG2 having a rotor connected to drive shaft 36. The present invention is not limited to the one applied to the vehicle, and may be applied to any vehicle as long as the vehicle includes a traveling motor, a battery, and a boost converter provided between the motor and the battery. Absent.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the motor MG2 corresponds to a “motor”, the HV battery 50 corresponds to a “battery”, the boost converter 55 corresponds to a “boost converter”, and the motor ECU 40 and the HVECU 70 correspond to “control means”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the vehicle manufacturing industry.

  20 hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 30 planetary gear, 36 drive shaft, 37 differential gear, 38a, 38b drive wheel, 40 motor electronic control unit (motor ECU), 41, 42 Inverter, 43, 44 Temperature sensor, 50 HV battery, 52 Electronic control unit (battery ECU) for battery, 54a High voltage system power line, 54b Battery voltage system power line, 54c Low voltage system power line, 55 Boost converter , 56 System main relay, 57 High voltage electrical equipment, 60 Air conditioner (A / C), 64 DC / DC converter, 66 Auxiliary battery, 67 Electric power steering (EPS), 68 Electronically controlled brake system (E B), 70 hybrid electronic control unit (HVECU), 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor, 90 barometric pressure sensor, MG1, MG2 motor.

Claims (1)

A vehicle comprising a motor, a battery, and a boost converter provided between the motor and the battery,
When the atmospheric pressure is equal to or higher than a predetermined atmospheric pressure, the boosting voltage of the boost converter is not limited, and when the atmospheric pressure is lower than the predetermined atmospheric pressure, limiting means for limiting the boosted voltage,
When the atmospheric pressure is lower than the predetermined atmospheric pressure and the temperature of the motor is equal to or higher than the predetermined temperature, the control means is more effective than when the atmospheric pressure is lower than the predetermined atmospheric pressure and the temperature of the motor is lower than the predetermined temperature. A vehicle that is a means of greatly limiting the boost voltage.

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