JP2013143861A - Control device for vehicle - Google Patents

Abstract

A vehicle control device capable of suppressing electromagnetic noise whose sound pressure level locally increases.
A vehicle control device used in an electric vehicle having motors MG1 and MG2 as driving force sources drives the motors MG1 and MG2 at predetermined distribution ratios R1 and R2 so that the system efficiency of the electric vehicle is maximized. The sound pressure level of the electromagnetic noise of one of the motors MG1 and MG2 is local compared to the other vehicle speed regions while the ECU is driving the motors MG1 and MG2 at the predetermined distribution ratios R1 and R2. In the vehicle speed regions A1 and A2 that increase rapidly, the motor torque Tm of one of the motors MG1 and MG2 whose sound pressure level has locally increased is reduced and the motor torque Tm of the other of the motors MG1 and MG2 is increased. Let me.
[Selection] Figure 2

Description

  The present invention relates to a vehicle control device applied to an electric vehicle including an electric motor as a driving force source.

  In recent years, as an electric vehicle to which this type of vehicle control device is applied, there is known an electric vehicle that includes a plurality of motors as a driving force source and controls the driving of each motor so as to obtain a driving force required for traveling of the vehicle. (For example, refer to Patent Document 1). The vehicle control device applied to this electric vehicle obtains a travel required output required to obtain a driving force necessary for traveling of the vehicle, and determines a shared output to be shared among the travel required outputs for each motor. Then, the output of each motor is controlled in accordance with each shared output. Further, in this vehicle control device, when determining the shared output of each motor, the shared output is determined so that the total power consumption of the plurality of motors is minimized. Thereby, each motor can always be driven in the maximum efficiency region.

  Incidentally, it is known that noise called electromagnetic noise (or magnetic noise) is generated from a motor used as a driving force source of an electric vehicle as described above. Electromagnetic noise is noise caused by electromagnetic vibration called electromagnetic excitation force. The electromagnetic excitation force is a vibration of the motor caused by an alternating magnetic field generated with an alternating current supplied to the motor.

  Further, the frequency of the alternating magnetic field varies depending on the frequency of the AC voltage applied to the motor. The frequency of electromagnetic noise also changes with the change in frequency of the alternating magnetic field. When the frequency of electromagnetic noise changes, the sound pressure level of electromagnetic noise also changes. In addition, when the vehicle enters the specific vehicle speed range where the frequency of the electromagnetic noise becomes equal to the resonance frequency of the motor, that is, the specific motor rotation speed range, the motor resonates and the sound pressure level of the electromagnetic noise is locally May increase.

  In such a case, electromagnetic noise having a locally increased sound pressure level is experienced as unpleasant noise by the driver. Therefore, in an electric vehicle using a motor as a driving force source, it is desirable to suppress unpleasant noise as described above.

JP-A-6-62508

  However, in the conventional vehicle control device described in Patent Document 1, no consideration is given to suppressing electromagnetic noise in which the sound pressure level locally increases. Therefore, in the conventional vehicle control device, if the motor is driven and controlled in a region where the sound pressure level of the electromagnetic noise of each motor is locally increased, the increased electromagnetic noise is experienced as unpleasant noise by the driver. was there.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a vehicle control device that can suppress electromagnetic noise in which the sound pressure level locally increases. .

  In order to achieve the above object, a vehicle control apparatus according to the present invention is (1) a vehicle control used for an electric vehicle including a first electric motor and a second electric motor as a driving force source for generating the driving force of the vehicle. A device that drives the first motor and the second motor at a predetermined distribution ratio so that the system efficiency of the electric vehicle including the efficiency of the first motor and the second motor is maximized. Control means for controlling the electromagnetic noise of one of the first electric motor and the second electric motor during driving of the first electric motor and the second electric motor at the predetermined distribution ratio. The motor torque of either the first motor or the second motor in which the sound pressure level is locally increased in a vehicle speed region where the sound pressure level of the vehicle is locally increased compared to other vehicle speed regions. Lowered Rutotomoni has a structure to raise the other one of the motor torque of the first motor and the second electric motor.

  With this configuration, in the vehicle control device according to the present invention, the control unit is configured to control one of the first electric motor and the second electric motor while driving the first electric motor and the second electric motor at a predetermined distribution ratio. In the vehicle speed region where the sound pressure level of electromagnetic noise is locally increased compared to other vehicle speed regions, one of the first motor and the second motor where the sound pressure level of electromagnetic noise is locally increased. While decreasing the motor torque, the motor torque of either the first motor or the second motor is increased. Here, the sound pressure level of the electromagnetic noise of the motor has a characteristic that it increases as the motor torque increases. Therefore, the sound pressure level of the electromagnetic noise generated by the motor can be reduced by reducing the motor torque of the one motor whose sound pressure level of the electromagnetic noise has locally increased. On the other hand, the total motor torque of the first motor and the second motor can be maintained by increasing the motor torque of the other motor whose sound pressure level of electromagnetic noise has not increased. A decrease in driving force can be prevented.

  Thus, the vehicle control apparatus according to the present invention can suppress electromagnetic noise in which the sound pressure level locally increases without reducing the driving force of the electric vehicle.

  ADVANTAGE OF THE INVENTION According to this invention, the vehicle control apparatus which can suppress the electromagnetic noise to which a sound pressure level increases locally can be provided.

1 is a schematic configuration diagram of an electric vehicle to which a vehicle control device according to an embodiment of the present invention is applied. It is a figure which shows the relationship between the sound pressure level of the electromagnetic noise which generate | occur | produces in each motor which concerns on embodiment of this invention, the distribution ratio of the motor torque between motors, and a vehicle speed. It is a figure which shows the relationship between the motor torque Tm2 which concerns on embodiment of this invention, and the sound pressure level of electromagnetic noise.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the embodiment of the present invention, an example will be described in which the vehicle control device is applied to a vehicle equipped with two electric motors as a driving force source, a so-called electric vehicle.

  As shown in FIG. 1, electric vehicle 10 includes motor generators (hereinafter simply referred to as motors) MG <b> 1 and MG <b> 2 as driving force sources that generate driving force of electric vehicle 10. Motor MG1 in the present embodiment constitutes a first electric motor according to the present invention, and motor MG2 constitutes a second electric motor according to the present invention.

  The electric vehicle 10 includes a power transmission mechanism 4, a differential gear 5, left and right drive wheels 6 </ b> L and 6 </ b> R, and a vehicle control device 8.

  The motors MG1 and MG2 convert electric power supplied from a battery 120, which will be described later, into mechanical power and output the mechanical power to the power transmission mechanism 4. The motors MG1 and MG2 are each composed of a permanent magnet AC synchronous motor or the like, and have a stator and a rotor (not shown). The stator receives a supply of AC power from inverters 11 and 12, which will be described later, and forms a rotating magnetic field. The rotor is coupled to the power transmission mechanism 4 and is rotated by being attracted to a rotating magnetic field.

  The motors MG1 and MG2 are each provided with a resolver (not shown) that detects the rotational angle position of the rotor. The resolver transmits a signal corresponding to the detected rotational angle position of the rotor to an electronic control unit (hereinafter simply referred to as ECU) 100 described later.

  The motors MG1 and MG2 can operate as an electric motor by receiving power supplied from the battery 120. On the other hand, when a motor shaft (not shown) is rotated by an external force, an electromotive force is generated to cause the battery 120 to operate. It is also possible to operate as a generator for charging.

  The power transmission mechanism 4 transmits the mechanical power output by the motors MG1 and MG2 to the left and right drive wheels 6L and 6R via the differential gear 5. As the power transmission mechanism 4, for example, a power integration unit that integrates and outputs the mechanical power output from each of the motors MG 1 and MG 2, and a mechanical power output from the power integration unit reduces the rotational speed and torque It is possible to use a mechanism provided with a speed reducing portion that increases the torque to be transmitted to the differential gear 5.

  Further, as the power integration unit, for example, a mechanism having two planetary gears corresponding to each of the motors MG1 and MG2 and a ring gear of these planetary gears coupled together can be used. The sun gears of the planetary gears are connected to the rotors of the motors MG1 and MG2, respectively. Further, such a power integration unit is provided with an output gear capable of transmitting power to the speed reduction unit on the outer periphery of the ring gear. As the speed reducer, for example, a gear mechanism including various gears that can mesh with the output gear and transmit the mechanical power output from the output gear to the differential gear 5 can be used.

  The differential gear 5 includes a ring gear (not shown) that meshes with the reduction portion of the power transmission mechanism 4 described above. The differential gear 5 distributes the mechanical power transmitted from the power transmission mechanism 4 to the ring gear to the left and right drive wheels 6L and 6R and outputs the distributed power.

  The vehicle control device 8 includes inverters 11 and 12 corresponding to the motors MG1 and MG2, an ECU 100, and a battery 120, respectively.

  Inverters 11 and 12 are connected to stators (not shown) of motors MG1 and MG2, respectively. The inverters 11 and 12 are configured to convert DC power supplied from the battery 120 into AC power and supply the AC power to the corresponding motors MG1 and MG2, respectively. Inverters 11 and 12 are configured to convert AC power from motors MG 1 and MG 2 to DC power and supply the battery 120. That is, the DC power converted by the inverters 11 and 12 is collected (stored) in the battery 120. Electric power supply and power recovery of the inverters 11 and 12 are controlled by the ECU 100.

  The ECU 100 includes, for example, a microcomputer including a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM and performs signal processing according to a program stored in advance in the ROM. It is like that. Various control constants and various maps are stored in advance in the ROM.

  Various sensors including an accelerator pedal position sensor 101 and a vehicle speed sensor 102 are connected to the ECU 100. The accelerator pedal position sensor 101 detects the amount of operation of the accelerator pedal 103 by the driver. The accelerator pedal position sensor 101 is connected to the ECU 100, and transmits a signal corresponding to the detected operation amount of the accelerator pedal 103 (hereinafter referred to as an accelerator operation amount Acc) to the ECU 100. The vehicle speed sensor 102 detects the vehicle speed V of the electric vehicle 10. The vehicle speed sensor 102 is connected to the ECU 100 and transmits a signal corresponding to the detected vehicle speed V to the ECU 100.

  Further, the ECU 100 sets the user request power P based on the accelerator operation amount Acc and the vehicle speed V that are input. The user required power P is a required power for driving the electric vehicle 10, and can be set by referring to a map in which the relationship between the accelerator operation amount Acc and the vehicle speed V and the user required power P is stored in advance, for example. . The ECU 100 drives and controls each of the motors MG1 and MG2 so that the required power corresponding to the user required power P is output from the power transmission mechanism 4.

  In addition, when driving control of the motors MG1 and MG2 based on the required power corresponding to the user required power P, the ECU 100 causes the motor MG1 and the motor MG2 to maximize the system efficiency of the electric vehicle 10 including the efficiency of the motors MG1 and MG2. Are driven at a predetermined distribution ratio. In other words, the ECU 100 drives the motor MG1 and the motor MG2 at a predetermined distribution ratio so that the motors MG1 and MG2 are driven at the optimum efficiency operating point at which the system loss of the electric vehicle 10 is minimized. Therefore, the driving force of the motors MG1 and MG2, that is, the motor torque Tm is determined by the predetermined distribution ratio.

  Further, the ECU 100 drives the motor MG1 and the motor MG2 at a predetermined distribution ratio, and the sound pressure level (dB) of the electromagnetic noise of either one of the motors MG1 and MG2 is locally compared with other vehicle speed regions. In the increasing vehicle speed regions A1 and A2 (see FIG. 2), the motor torque Tm of any one of the motors MG1 and MG2 whose sound pressure level (dB) is locally increased is reduced. At the same time, the ECU 100 increases the motor torque Tm of the other of the motors MG1 and MG2. As a result, it is possible to suppress electromagnetic noise of the motors MG1 and MG2 that increases in the vehicle speed regions A1 and A2 (see FIG. 2). At this time, the total motor torque Tmt of the motor torque Tm1 of the motor MG1 and the motor torque Tm2 of the motor MG2 is kept unchanged after the change of the motors Tm1 and Tm2. Therefore, even if the distribution ratio of the motors MG1 and MG2 changes, the driving force of the electric vehicle 10 does not change. Here, the ECU 100 can arbitrarily change the motor torques Tm1 and Tm2 by controlling the inverters 11 and 12, for example.

  Hereinafter, such control is referred to as electromagnetic noise suppression control, and details thereof will be described later. In this embodiment, in the electromagnetic noise suppression control, the motor torques Tm1 and Tm2 are changed. However, the present invention is not limited to this, and the motor output Pm1 determined by the motor torques Tm1 and Tm2 and the motor rotation speeds Nm1 and Nm2 is used. , Pm2 may be changed. ECU 100 in the present embodiment constitutes a control means according to the present invention. Further, the motor torque Tm in the present embodiment corresponds to the motor torque in the present invention.

  The battery 120 is configured as a chargeable / dischargeable secondary battery made of, for example, nickel metal hydride or lithium ion. The battery 120 exchanges electric power with the motors MG1, MG2 and other electric loads. Between the inverters 11 and 12, a boost converter (not shown) that boosts the voltage of the battery 120 and converts it into a supply voltage of the inverters 11 and 12 is interposed. For example, as will be described later, when a fuel cell is further provided in addition to the battery 120 as a power source of the electric vehicle 10, the boost converter can be omitted.

  Incidentally, it is known that motors MG1 and MG2 used as driving force sources for the electric vehicle 10 generate electromagnetic noise caused by electromagnetic vibration called electromagnetic excitation force. The electromagnetic excitation force is vibrations of the motors MG1 and MG2 generated by an alternating magnetic field generated with an alternating current supplied to the motors MG1 and MG2. Therefore, when the electric vehicle 10 is traveling, the motor MG1 or the motor MG2 resonates when a specific vehicle speed region, that is, a specific motor rotation speed region, in which the frequency of electromagnetic noise becomes equal to the resonance frequency of the motor MG1 or MG2. As a result, the sound pressure level (dB) of electromagnetic noise may increase locally. In such a case, electromagnetic noise having a locally increased sound pressure level (dB) is experienced as unpleasant noise by the driver.

  Therefore, in the present embodiment, the electromagnetic noise suppression control described below is executed in order to suppress such electromagnetic noise that locally increases the sound pressure level (dB).

  The electromagnetic noise suppression control executed by the ECU 100 according to the present embodiment will be described with reference to FIGS. 2 (a) to 2 (d) and FIG. 2A to 2D are examples, and various values such as the vehicle speeds V1 and V2 and the sound pressure level (dB) shown in these drawings are the values of the motors MG1 and MG2. It depends on the original and motor housing specifications.

  In the following description, an example in which motors MG1 and MG2 having different specifications are used will be described. However, even if the specifications of the motors MG1 and MG2 are the same, if the gear ratio of the planetary gear and the rigidity of the motor housing (case) are different, the electromagnetic noise is the same as when the specifications of the motors MG1 and MG2 are different from each other. The location where the sound pressure level (dB) increases locally may differ between the motor MG1 and the motor MG2, and in this case, the same effect as in the present embodiment can be obtained.

  As shown in FIG. 2 (a), the motor MG2 has a relatively low vehicle speed range compared to the motor MG1 shown in FIG. 2 (b), more specifically, the sound of electromagnetic noise having a peak in the vehicle speed V1 (km / h). The pressure level (dB) increases locally. Further, the sound pressure level (dB) of the electromagnetic noise at this time increases as the motor torque Tm2 (N · m) of the motor MG2 increases. The solid line shown in FIG. 2A indicates the sound pressure level (dB) of electromagnetic noise when the motor torque Tm2 (N · m) is relatively large, and the broken line indicates that the motor torque Tm2 (N · m) is relatively high. The sound pressure level (dB) of the electromagnetic noise when it is small is shown.

  As shown in FIG. 2B, the motor MG1 has a higher vehicle speed range than the motor MG2 shown in FIG. 2A, specifically a vehicle speed V2 (km / h) faster than the vehicle speed V1 (km / h). ) As a peak, the sound pressure level (dB) of electromagnetic noise locally increases. Further, the sound pressure level (dB) of the electromagnetic noise at this time increases as the motor torque Tm1 (N · m) of the motor MG1 increases as in the characteristics of the motor MG2. The solid line shown in FIG. 2B indicates the sound pressure level (dB) of electromagnetic noise when the motor torque Tm1 (N · m) is relatively large, and the broken line indicates that the motor torque Tm1 (N · m) is relatively high. The sound pressure level (dB) of the electromagnetic noise when it is small is shown.

  As shown in FIGS. 2A and 2B, the sound pressure level (dB) of the electromagnetic noise of the motor MG2 at the vehicle speed V1 (km / h) is the electromagnetic pressure of the motor MG2 at the vehicle speed V2 (km / h). It is larger than the sound pressure level (dB) of noise.

  FIG. 2C is a diagram showing the distribution ratio (%) of the motor torques Tm1 and Tm2 and the vehicle speed V (km / h). In FIG. 2C, two vehicle speed regions A1 and A2 are vehicle speed regions including vehicle speeds V1 and V2 at which the sound pressure level (dB) of electromagnetic noise increases locally. In the vehicle speed regions A1 and A2, the above-described electromagnetic noise suppression control is executed by the ECU 100. That is, the vehicle speed area A is an electromagnetic noise suppression control execution section. On the other hand, the vehicle speed region other than the vehicle speed regions A1 and A2 is a vehicle speed region in which the motors MG1 and MG2 are driven at a distribution ratio (%) that maximizes the system efficiency of the electric vehicle 10. Here, when the distribution ratio (%) of the motor torque Tm1 (N · m) when the system efficiency of the electric vehicle 10 is maximized is R1, the distribution ratio (%) of the motor torque Tm2 (N · m) is 100−R1 = R2 (%). For example, the operating point of the motors MG1 and MG2 driven at the distribution ratio R1 (%) and the distribution ratio R2 (%) at this time is set as the optimum efficiency operating point.

  As shown in FIG. 2 (c), first, the ECU 100 drives the motors MG1 and MG2 at predetermined distribution ratios R1 and R2 to drive the electric vehicle 10 so that the vehicle speed V (km / h) is in the vehicle speed range A1. Upon entering, the motor torque Tm2 (N · m) of the motor MG2 in which the sound pressure level (dB) of the electromagnetic noise is locally increased (see FIG. 2A) is reduced. At the same time, the ECU 100 increases the motor torque Tm1 (N · m) of the motor MG1.

  Here, a specific change in the motor torque Tm2 (N · m) will be described with reference to FIG.

  The sound pressure level (dB) shown in FIG. 3 is a total sound pressure level (dB) obtained by summing up electromagnetic noise generated by the motors MG1 and MG2. In FIG. 3, a solid line F1 indicates the total sound pressure level (dB) when the total motor torque Tmt (N · m) of the motor MG1 and the motor MG2 is a relatively small motor torque Tmt1 (N · m). . On the other hand, the solid line F2 indicates the total sound pressure level (dB) when the motor torque Tmt2 (N · m) is larger than the motor torque Tmt1 (N · m).

  When the total sound pressure level (dB) does not exceed the sound pressure threshold value S at the efficiency optimum operating point as indicated by the solid line F1 shown in FIG. 3, the electromagnetic noise suppression control is not executed, that is, the motor torque Tm2. The distribution ratio (%) that can be driven at the optimum efficiency operating point is maintained without changing the distribution ratio (%) of (N · m).

  On the other hand, when the total sound pressure level (dB) exceeds the sound pressure threshold value S at the efficiency optimum operating point as indicated by the solid line F2 shown in FIG. 3, the electromagnetic noise suppression control is executed and the motor torque Tm2 ( The distribution ratio (%) of N · m) is changed from the distribution ratio R2 (%) at the optimum efficiency operating point to the distribution ratio R2-α (%) that does not exceed the sound pressure threshold value S. At the same time, the distribution ratio R1 (%) of the motor torque Tm1 (N · m) of the motor MG1 driven at the optimum efficiency operating point is changed to the distribution ratio R1 + α (%) as shown in FIG. The Therefore, in the electromagnetic noise suppression control, the motor torque Tmt2 (N · m) is maintained as it is even if the distribution ratios R1 and R2 are changed. That is, the driving force of the electric vehicle 10 does not change.

  Next, as shown in FIG. 2C, when the vehicle speed V (km / h) enters the vehicle speed region A2, the ECU 100 locally increases the sound pressure level (dB) of the electromagnetic noise (FIG. 2B). The motor torque Tm1 (N · m) of the motor MG1 thus referred to is reduced. At the same time, the ECU 100 increases the motor torque Tm2 (N · m) of the motor MG2. Specifically, the ECU 100 increases the distribution ratio R2 (%) of the motor torque Tm2 (N · m) and the distribution ratio R1 (% of the motor torque Tm1 (N · m), contrary to the vehicle speed region A1. ). The method for changing the motor torque Tm1 (N · m) and the like are substantially the same as the method for changing the motor torque Tm2 (N · m) and the description thereof is omitted.

  Thus, in the present embodiment, as shown in FIG. 2D, by executing the electromagnetic noise suppression control, as shown in FIG. 2D, the electromagnetic noise suppression control is not executed, as shown by the solid line. It is possible to suppress the sound pressure level (dB) of the electromagnetic noise of the motors MG1 and MG2 in the vehicle speed regions A1 and A2.

  Further, the ROM of the ECU 100 stores the sound pressure level characteristics of electromagnetic noise according to the rotational speed (rpm) or the vehicle speed V (km / h) of the motors MG1, MG2, and the sound pressure level characteristics and the motor torque Tm1 (N · The relationship between m) and motor torque Tm2 (N · m) is experimentally determined and stored in advance. Therefore, the ECU 100 can determine whether or not to execute the electromagnetic noise suppression control by referring to these relationships.

  As described above, in the vehicle control device 8 according to the present embodiment, the ECU 100 is driving the motors MG1 and MG2 while driving the motors MG1 and MG2 at the optimum efficiency operating point, that is, at the predetermined distribution ratios R1 and R2. The sound pressure level (dB) of any one of the electromagnetic noises is locally increased as compared with other vehicle speed regions (vehicle speed regions where the motors MG1 and MG2 can be driven at the optimum efficiency operating point). , The motor torque Tm (N · m) of one of the motors MG1 and MG2 in which the sound pressure level (dB) of the electromagnetic noise is locally increased is reduced. At the same time, the ECU 100 increases the motor torque Tm (N · m) of one of the motors MG1 and MG2.

  Here, the sound pressure level (dB) of the electromagnetic noise of the motors MG1 and MG2 has a characteristic of increasing as the motor torque Tm (N · m) increases. Therefore, the sound pressure level (dB) of the electromagnetic noise generated by the motor is reduced by reducing the motor torque Tm (N · m) of the one motor whose sound pressure level (dB) of the electromagnetic noise is locally increased. can do. On the other hand, by increasing the motor torque Tm (N · m) of the other motor whose sound pressure level (dB) of electromagnetic noise has not increased, the total motor torque Tmt (N · m) of the motors MG1 and MG2 is increased. Can be maintained, and a reduction in the driving force of the electric vehicle 10 can be prevented.

  As described above, the vehicle control device 8 according to the present embodiment can suppress electromagnetic noise in which the sound pressure level (dB) locally increases without reducing the driving force of the electric vehicle 10.

  In the present embodiment, the example in which the vehicle control device 8 is applied to the electric vehicle 10 that uses the battery 120 made of a chargeable / dischargeable secondary battery as a power source has been described. The present invention is also applicable to a fuel cell vehicle that further includes a fuel cell in addition to the battery 120.

  As described above, the vehicle control device according to the present invention can suppress electromagnetic noise that locally increases the sound pressure level, and is applied to an electric vehicle that includes an electric motor as a driving force source. Useful for control devices.

8 Vehicle Control Device 10 Electric Vehicle 11, 12 Inverter 100 ECU (Control Unit)
101 Accelerator pedal position sensor MG1 Motor (first electric motor)
MG2 motor (second electric motor)

Claims (1)

A vehicle control device used in an electric vehicle including a first electric motor and a second electric motor as a driving force source for generating a driving force of the vehicle,
Control means for driving the first motor and the second motor at a predetermined distribution ratio so that the system efficiency of the electric vehicle including the efficiency of the first motor and the second motor is maximized. ,
The control means is configured such that the sound pressure level of the electromagnetic noise of one of the first motor and the second motor is different while the first motor and the second motor are being driven at the predetermined distribution ratio. In the vehicle speed region that locally increases compared to the vehicle speed region, the motor torque of either the first motor or the second motor in which the sound pressure level has locally increased is reduced, and A vehicle control device that increases the torque of the other of the first electric motor and the second electric motor.

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