JP2010220305A - Electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise the temperature of a battery to the extent that the temperature of a reactor does not become excessively high without providing a sensor for individually detecting the temperatures of the reactor and the like. <P>SOLUTION: In an electric vehicle, voltage increase control is carried out in accordance with the following flow: when the rest time Th from when an ignition switch is turned off to when the ignition switch is turned on is equal to or longer than a predetermined time Thref (S100), a temperature rise time Ts is so set that it becomes longer as the start time water temperature Tw0 becomes lower (S110). Until the temperature rise time Ts passes or a temperature raise request ceases, voltage increase control for raising temperature is carried out for boost converter control by using a relatively low carrier frequency CF2 (S120 to S140). After the temperature rise time Ts passes or the temperature raise request ceases, normal voltage increase control is carried out and the boost converter is controlled using a normal carrier frequency CF1 higher than the carrier frequency CF2 (S150). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric vehicle.

  Conventionally, this type of electric vehicle includes a motor generator connected to driving wheels, an inverter that drives the motor generator, a secondary battery, a transistor, and a reactor. And a boost converter that boosts the voltage and supplies it to an inverter has been proposed (see, for example, Patent Document 1). In this electric vehicle, when the temperature of the secondary battery is lower than a predetermined temperature, the transistor is switched at a lower carrier frequency (transistor switching frequency) than when the temperature of the secondary battery is higher than the predetermined temperature. The power loss during the switching operation of the converter is reduced.

JP 2007-26700 A

  In such an electric vehicle, when the transistor is switched at a low carrier frequency, in addition to reducing the power loss of the boost converter, it is possible to promote the temperature rise of the secondary battery by increasing the ripple current. Since the temperature of the reactor and the like easily rises, it is one of the problems to raise the temperature of the secondary battery in a range where the temperature of the reactor and the like does not become excessively high. In order to solve this problem, it is conceivable to provide a sensor that individually detects the temperature of the reactor and control the boost converter while detecting the temperature of the reactor, but in this case, the number of sensors increases. End up.

  The main object of the electric vehicle of the present invention is to raise the temperature of the battery in a range in which the temperature of the reactor does not become excessively high without providing a sensor for individually detecting the temperature of the reactor or the like.

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

The electric vehicle of the present invention is
An electric motor that outputs power for traveling, a drive circuit that drives the electric motor, a battery that has a negative terminal connected to the negative electrode side of the drive circuit, and a closed circuit that includes the drive circuit, are connected in series to each other A first and a second switching element; a reactor connected to an intermediate point of the first and the second switching elements; and a positive terminal of the battery; and the switching by the first and the second switching elements. A boost converter capable of boosting a voltage of a battery and supplying the boosted voltage to the drive circuit, a cooling system for cooling the electric motor, the drive circuit, and the boost converter using a cooling medium, and a torque required for the electric motor Electric motor control for controlling the electric motor to be output from the electric motor, and controlling the boost converter so that the voltage on the drive circuit side becomes a target voltage And control means for performing a step-up control, the electric vehicle comprising,
The control means performs the step-up control using a first carrier frequency when the leaving time from ignition off to ignition on is less than a predetermined time set in advance, and when the leaving time is equal to or longer than the predetermined time, The second carrier that is lower than the first carrier frequency until the time for temperature increase set to tend to become longer as the temperature of the cooling medium elapses or until the temperature increase request that is a request for temperature increase of the battery is not made. Means for performing the step-up control using a frequency, and performing the step-up control using the first carrier frequency after the time for temperature increase has elapsed or the temperature increase request is not made.
It is characterized by that.

  In the electric vehicle of the present invention, the first boost control is performed to control the boost converter so that the voltage on the drive circuit side becomes the target voltage when the leaving time from the ignition off to the ignition on is less than a predetermined time set in advance. This is done using the carrier frequency. On the other hand, when the standing time is longer than a predetermined time, the set time for temperature rising tends to increase as the temperature of the cooling medium used for cooling the motor, the drive circuit, and the boost converter decreases, or the battery needs to be heated Until the temperature increase request is no longer made, the pressure increase control is performed using the second carrier frequency lower than the first carrier frequency, and after the temperature increase time elapses or the temperature increase request is not made, the first Boost control is performed using the carrier frequency. That is, when the standing time is relatively long, the boost control is performed using the second carrier frequency until the temperature increase time corresponding to the cooling medium elapses or the temperature increase request is not made. Thus, the temperature of the battery can be raised within a range in which the temperature of the reactor does not become excessively high without providing a sensor for individually detecting the temperature of the reactor or the like. Here, the predetermined time is a time required for the temperature of the reactor to sufficiently approach the temperature of the cooling medium (the difference between the temperature of the reactor and the temperature of the cooling medium and the outside air temperature or the vehicle room temperature becomes sufficiently small). It can also be.

It is a block diagram which shows the outline of a structure of the electric vehicle 20 as one Example of this invention. It is a flowchart which shows an example of the pressure | voltage rise control routine performed by the electronic control unit 60 of an Example. It is explanatory drawing which shows an example of the temperature setting time setting map.

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

  FIG. 1 is a configuration diagram showing an outline of a configuration of an electric vehicle 20 as an embodiment of the present invention. As shown in the figure, an electric vehicle 20 according to the embodiment includes, for example, a motor 30 that is configured as a synchronous generator motor and that has a rotor connected to a drive shaft 22 that is connected to drive wheels 26a and 26b via a differential gear 24. An inverter 32 that drives the motor 30, a battery 40 configured as a lithium ion battery, a boost converter 42 that can convert the voltage of the power from the battery 40 and supply it to the inverter 32, and the inverter 32 side of the boost converter 42 Cooling water in the circulation flow path 54 including the smoothing capacitor 34 connected to the battery 40, the smoothing capacitor 44 connected to the battery 40 side of the boost converter 42, the motor 30, the inverter 32, the boost converter 42, and the radiator 52. Is circulated by the electric pump 56, and the motor 30, the inverter 32, Between the cooling system 50 for cooling the barter 42 and the voltage of the smoothing capacitor 34 (hereinafter referred to as “high voltage system voltage”) from the voltage sensor 36 attached between the terminals of the smoothing capacitor 34 or between the terminals of the smoothing capacitor 44. The voltage of the smoothing capacitor 44 from the voltage sensor 46 attached to the battery, the battery temperature Tb from the temperature sensor 41 that detects the temperature of the battery 40, and the cooling water temperature from the temperature sensor 58 that detects the temperature of the cooling water in the cooling system 50. Tw, ignition signal from the ignition switch 61, shift position from the shift position sensor 62 that detects the position of the shift lever, accelerator opening from the accelerator pedal position sensor 64 that detects the depression amount of the accelerator pedal, and depression amount of the brake pedal Brake pedal position to detect Comprising a brake position from capacitors 66, inverter 32 and boost converter 42 inputs the vehicle speed from the vehicle speed sensor 68, the electronic control unit 60 for controlling the entire vehicle such as an electric pump 56, a.

  Boost converter 42 includes two transistors T1 and T2, two diodes D1 and D2 connected in parallel to transistors T1 and T2, and a reactor L. The two transistors T1 and T2 are respectively connected to the positive electrode side and the negative electrode side of the inverter 32, and the reactor L is connected to an intermediate point thereof. Further, the positive terminal and the negative terminal of the battery 40 are connected to the reactor L and the negative side of the inverter 32, respectively. Therefore, the on / off control of the transistors T1 and T2 increases the voltage of the DC power of the battery 40 and supplies it to the inverter 32, or decreases the DC voltage acting on the inverter 32 and charges the battery 40. be able to.

  The electric vehicle 20 of the embodiment basically travels by drive control described below that is executed by the electronic control unit 60. In the electronic control unit 60, first, the required torque required for the motor 30 for traveling is set according to the accelerator opening from the accelerator pedal position sensor 64 and the vehicle speed from the vehicle speed sensor 68, and the set required torque and Based on the rotation speed of the motor 30 detected by a rotation speed sensor (not shown), the target voltage on the high voltage side to be supplied to the inverter 32 is set so as to increase as the required torque and the rotation speed of the motor 30 increase. Then, switching control of the switching element of the inverter 32 is performed so that the required torque is output from the motor 30, and switching control of the transistors T1, T2 of the boost converter 42 is performed so that the high voltage system voltage from the voltage sensor 36 becomes the target voltage. In the electric vehicle 20 of the embodiment, the motor 30, the inverter 32, and the boost converter 42 are cooled by controlling the electric pump 56 based on the cooling water temperature Tw to circulate the cooling water in the circulation passage 54. Yes.

  Next, the control of the boost converter 42 in the drive control of the electric vehicle 20 of the embodiment will be described. FIG. 2 is a flowchart showing an example of a boost control routine executed by the electronic control unit 60 when the ignition is turned on. When this routine is executed, the electronic control unit 60 first determines the leaving time Th from when the ignition is turned off until the ignition is turned on, and the temperature of the reactor L and the like of the boost converter 42 after the ignition is turned off is the cooling water temperature Tw. A predetermined time Thref (for example, 2 hours, 3 hours, etc.) as a time required to sufficiently approach (the difference between the temperature of the reactor L, the cooling water temperature Tw, and the outside air temperature or the vehicle room temperature is within a predetermined range) In comparison (step S100), when the leaving time Th is less than the predetermined time Thref, it is determined that the temperature of the reactor L or the like is not yet sufficiently close (relatively high) to the cooling water temperature Tw, and the transistor is operated at the normal carrier frequency CF1. Normal boost control for switching control of T1 and T2 is performed (step S150). When it is Nisshon'ofu (step S160), and terminates this routine. On the other hand, when the leaving time Th is equal to or longer than the predetermined time Thref, it is determined that the temperature of the reactor L or the like is sufficiently close to the cooling water temperature Tw, and based on the start-up water temperature Tw0 that is the cooling water temperature Tw when the ignition is turned on, FIG. The temperature increase time Ts is set using the temperature increase time setting map exemplified in (Step S110), and whether or not a temperature increase request is made is determined by, for example, the battery temperature Tb and a predetermined temperature Tbref (for example, 0 ° C. or (Step S120), and when no temperature increase request is made (when the battery temperature Tb is equal to or higher than the predetermined temperature Tbref), normal boost control is performed (step S150). When the ignition is turned off (step S160), this routine is terminated. On the other hand, when a temperature increase request is made (when the battery temperature Tb is lower than the predetermined temperature Tbref), the carrier lower than the normal carrier frequency CF1 until the temperature increase time Ts elapses or the temperature increase request is not made. Step-up boost control is performed to control switching of the transistors T1 and T2 at the frequency CF2 (steps S120 to S140), and normal boost control is performed after the temperature-up time Ts elapses or the temperature rise request is not made. (Step S150) When the ignition is turned off (Step S160), this routine is terminated. When boosting control for increasing the temperature by controlling the transistors T1 and T2 with a relatively low carrier frequency CF2 is performed, the ripple current increases and the temperature increase of the battery 40 can be promoted. Here, the temperature increase time Ts is a time during which the temperature increase control can be performed within a range in which the temperature of the reactor L or the like does not become excessively high. In the embodiment, the reactor becomes lower as the startup water temperature Tw0 is lower. Considering that the temperature when the ignition is on, such as L, is low, the temperature rise time Ts tends to become longer as the startup water temperature Tw0 is lower. The warming time Ts was set. When the boost control for raising the temperature is performed, the temperature of the reactor L of the boost converter 42 or the like may be relatively high. Therefore, the boost control for raising the temperature is performed while individually detecting the temperature of the reactor L or the like. In this case, the number of sensors for detecting the temperature increases. On the other hand, in the embodiment, when the standing time Th is relatively long and it can be determined that the temperature of the reactor L of the boost converter 42 is sufficiently close to the cooling water temperature Tw, the temperature raising time based on the startup water temperature Tw0. Since temperature increase control is performed over Ts, the temperature of the battery 40 is increased within a range in which the temperature of the reactor L or the like does not become excessively high without providing a sensor or the like for detecting the temperature of the reactor L itself. Can do.

  According to the electric vehicle 20 of the above-described embodiment, when the leaving time Th from when the ignition is turned off until when the ignition is turned on is equal to or longer than the predetermined time Thref, the temperature rise is set to become longer as the startup water temperature Tw0 is lower. Since the boosting control for raising the temperature is performed until the temperature rise time Ts elapses or the temperature raising request is not made, and the temperature raising time Ts elapses or the temperature raising request is made no longer made, the normal pressure raising control is performed. Even without providing a sensor for individually detecting the temperature such as L, the temperature of the battery 40 can be raised within a range where the temperature of the reactor L or the like does not become excessively high.

  In the electric vehicle 20 of the embodiment, when the leaving time Th is equal to or longer than the predetermined time Thref, the temperature rises in a tendency to become longer as the startup water temperature Tw0 is lower using the temperature increase time setting map illustrated in FIG. Although the use time Ts is set, the temperature increase time Ts may be set such that the lower the start-up water temperature Tw0 is, the longer the time is in steps with one or more stages. Further, when the driver can change the carrier frequency CF2 when the boost control for temperature increase is performed (for example, the driver can change the carrier frequency from a plurality of frequencies in consideration of noise generated by switching of the transistors T1 and T2). For example, when CF2 can be set), the temperature rise time tends to become longer as the startup water temperature Tw0 is lower, and the carrier frequency CF2 is smaller, that is, the temperature of the battery 40 is more easily promoted. Ts may be set.

  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 30 corresponds to a “motor”, the inverter 32 corresponds to a “drive circuit”, the battery 40 corresponds to a “battery”, the boost converter 42 corresponds to a “boost converter”, and the cooling system 50. Corresponds to the “cooling system”, and a required torque required for the motor 30 for traveling is set according to the accelerator opening from the accelerator pedal position sensor 64 and the vehicle speed from the vehicle speed sensor 68, and the request from the motor 30 is set. In the switching control of the transistors T1 and T2 of the boost converter 42 so that the switching element of the inverter 32 is controlled so that torque is output and the high-voltage system voltage from the voltage sensor 36 becomes the target voltage, after the ignition is turned off. If the leaving time Th until the ignition is turned on is less than the predetermined time Thref The normal boost control for switching and controlling the transistors T1 and T2 at the normal carrier frequency CF1 is performed, and when the standing time Th is equal to or longer than the predetermined time Thref, the temperature rise is set to become longer as the startup water temperature Tw0 is lower. Until the use time Ts elapses or the temperature increase request is not made, the step-up boost control for switching the transistors T1 and T2 is performed at the carrier frequency CF2 lower than the carrier frequency CF1, and the temperature rise time Ts elapses or rises. After the temperature request is no longer made, the electronic control unit 60 that performs normal boost control corresponds to “control means”.

  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 manufacturing industry of electric vehicles.

  20 electric vehicle, 22 drive shaft, 24 differential gear, 26a, 26b drive wheel, 30 motor, 32 inverter, 34 smoothing capacitor, 36 voltage sensor, 40 battery, 41 temperature sensor, 42 boost converter, 44 smoothing capacitor, 46 Voltage sensor, 50 Cooling system, 52 Radiator, 54 Circulating flow path, 56 Electric pump, 58 Temperature sensor, 60 Electronic control unit, 61 Ignition switch, 62 Shift position sensor, 64 Accelerator pedal position sensor, 66 Brake pedal position sensor, 68 Vehicle speed sensor, D1, D2 diode, L reactor, T1, T2 transistor.

Claims (1)

An electric motor that outputs power for traveling, a drive circuit that drives the electric motor, a battery that has a negative terminal connected to the negative electrode side of the drive circuit, and a closed circuit that includes the drive circuit, are connected in series to each other A first and a second switching element; a reactor connected to an intermediate point of the first and the second switching elements; and a positive terminal of the battery; and the switching by the first and the second switching elements. A boost converter capable of boosting a voltage of a battery and supplying the boosted voltage to the drive circuit, a cooling system for cooling the electric motor, the drive circuit, and the boost converter using a cooling medium, and a torque required for the electric motor Electric motor control for controlling the electric motor to be output from the electric motor, and controlling the boost converter so that the voltage on the drive circuit side becomes a target voltage And control means for performing a step-up control, the electric vehicle comprising,
The control means performs the step-up control using a first carrier frequency when the leaving time from ignition off to ignition on is less than a predetermined time set in advance, and when the leaving time is equal to or longer than the predetermined time, The second carrier that is lower than the first carrier frequency until the time for temperature increase set to tend to become longer as the temperature of the cooling medium elapses or until the temperature increase request that is a request for temperature increase of the battery is not made. Means for performing the step-up control using a frequency, and performing the step-up control using the first carrier frequency after the time for temperature increase has elapsed or the temperature increase request is not made.
An electric vehicle characterized by that.

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