JP2013169028A - Control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a ripple current for a control device of a vehicle that includes a first AC motor and a second AC motor that are power sources for driving.SOLUTION: An ECU 3 includes: a torque calculating part 31 that obtains a request drive torque T based on an accelerator opening θ; a limit torque setting part 32 that sets a limit torque Tc; and a torque distribution part 34 that makes a drive torques TR1 output from a motor M1, a request drive torque T, when a request drive torque T is not more than a maximum torque Tm1 outputtable from the motor M1, makes the drive torque TR1 output from the motor M1, the limit torque Tc set not more than the maximum torque Tm1, when the request drive torque T is larger than the maximum torque Tm1 outputtable from the motor M1, and makes a drive torque TR2 output from a motor M2, a torque of difference subtracted the limit torque Tc from the request drive torque T (request drive torque T-limit torque Tc).

Description

  The present invention relates to a vehicle control device including a first AC motor and a second AC motor that are driving power sources.

  2. Description of the Related Art Conventionally, various devices and methods for determining an output torque to be shared by a plurality of drive motors in a vehicle including a plurality of drive motors (corresponding to “AC motors”) have been proposed.

  For example, multiple combinations of output torques to be shared by two motors are set as output sets, and the total power consumption of the motor to be operated is calculated for each set. A drive control apparatus for a plurality of motors is disclosed in which the assignment of each motor is determined by selecting the smallest set (see Patent Document 1). According to this drive control apparatus for a plurality of motors, it is described that each motor is always operated in the maximum efficiency region, and that there is an effect that there is no difference in driving force when the motor is switched.

Japanese Patent Laid-Open No. 7-131994

  However, in the drive control apparatus for a plurality of motors described in Patent Document 1, since a combination of output torques that minimizes the total power consumption is selected, there is a risk that deterioration of components due to ripple current generated by inverter switching may proceed. There is.

  That is, for example, as the number of motors used for traveling increases, the ripple current generated by switching of the inverter increases. Therefore, in the drive control apparatus for a plurality of motors described in Patent Document 1, the number of motors used for running increases, and there is a risk that the ripple current increases.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle control device capable of reducing ripple current.

  In order to solve the above problems, a vehicle control apparatus according to the present invention is configured as follows.

  That is, the vehicle control device according to the present invention is a vehicle control device including a first AC motor and a second AC motor that are driving power sources, and an output shaft that transmits driving torque to wheels. When the required drive torque is equal to or less than the maximum torque that can be output from the first AC motor to the output shaft, the torque output from the first AC motor to the output shaft is set as the required drive torque, and the required drive When the torque is larger than the maximum torque that can be output from the first AC motor to the output shaft, the torque output from the first AC motor to the output shaft is set as a limit torque set to be equal to or less than the maximum torque. The torque output from the second AC motor to the output shaft is a difference torque obtained by subtracting the limit torque from the required drive torque.

  According to the vehicle control apparatus having such a configuration, when the required drive torque is equal to or less than the maximum torque that can be output from the first AC motor to the output shaft, the output is output from the first AC motor to the output shaft. When the required drive torque is greater than the maximum torque that can be output from the first AC motor to the output shaft, the torque is output from the first AC motor to the output shaft. Since the torque is the limit torque set to be equal to or less than the maximum torque, the torque output from the second AC motor to the output shaft is the difference between the required drive torque and the limit torque. The current can be reduced.

  That is, when the required drive torque is equal to or less than the maximum torque that can be output from the first AC motor to the output shaft, the torque output from the first AC motor to the output shaft is set as the required drive torque. Therefore, since the number of AC motors used for traveling is one, the ripple current can be reduced. Further, when the required drive torque is larger than the maximum torque that can be output from the first AC motor to the output shaft, the torque output from the first AC motor to the output shaft is set to be equal to or less than the maximum torque. Since the torque output from the second AC motor to the output shaft is the difference torque obtained by subtracting the limit torque from the required drive torque, the limit torque is set to an appropriate value. As a result, the ripple current can be reduced.

  The vehicle control apparatus according to the present invention further includes a storage battery that supplies power to the first AC motor and the second AC motor, and the limit torque is superimposed on a current output from the storage battery. It is preferable to set to reduce the current.

  According to the control apparatus for a vehicle having such a configuration, the required torque is set from the first AC motor because the limit torque is set to reduce the ripple current superimposed on the current output from the storage battery. When the torque is larger than the maximum torque that can be output to the output shaft, the ripple current can be reduced.

  The vehicle control device according to the present invention may set the limit torque based on at least one of a temperature of the storage battery, a remaining capacity of the storage battery, and a degree of deterioration of the storage battery. preferable.

  According to the vehicle control device having such a configuration, the limit torque is set based on at least one of the temperature of the storage battery, the remaining capacity of the storage battery, and the degree of deterioration of the storage battery. Since the limit torque can be set to an appropriate value, the ripple current can be reduced.

  Further, in the vehicle control apparatus according to the present invention, the first AC motor includes a sine wave pulse width modulation method, a pulse width overmodulation control method in which the amplitude of the fundamental wave component is larger than the sine wave pulse width modulation method, In addition, it is preferable that at least two control methods among the three control methods of the rectangular wave voltage control method can be executed.

  According to the vehicle control apparatus having such a configuration, the first AC motor has a sine wave pulse width modulation method, a pulse width overmodulation control method in which the amplitude of the fundamental wave component is larger than that of the sine wave pulse width modulation method, And since it is comprised so that control by at least two types of control methods among three types of control methods of a rectangular wave voltage control method is executable, it is appropriate according to the output torque and rotational speed of the 1st AC motor. Since the control method can be selected, the efficiency of the first AC motor can be improved.

  In the vehicle control device according to the present invention, it is preferable that the limit torque is set based on the control method of the first AC motor.

  According to the control apparatus for a vehicle having such a configuration, since the limit torque is set based on the control method of the first AC motor, the limit torque can be set to a more appropriate value. The ripple current can be further reduced.

  In the vehicle control apparatus according to the present invention, the maximum torque that can be output from the first AC motor to the output shaft is preferably larger than the maximum torque that can be output from the second AC motor to the output shaft. .

  According to the vehicle control apparatus having such a configuration, the maximum torque that can be output from the first AC motor to the output shaft is greater than the maximum torque that can be output from the second AC motor to the output shaft. The range of the required drive torque in which the required drive torque can be output by only one AC motor (here, the first AC motor) can be expanded.

  In the vehicle control apparatus according to the present invention, it is preferable that the first AC motor and the second AC motor are directly connected to the output shaft, respectively.

  According to the vehicle control apparatus having such a configuration, since the first AC motor and the second AC motor are directly connected to the output shaft, respectively, the first AC motor and the second AC motor are The output can be transmitted to the drive wheel with a simple structure.

  According to the vehicle control apparatus of the present invention, when the required drive torque is equal to or less than the maximum torque that can be output from the first AC motor to the output shaft, the output is output from the first AC motor to the output shaft. Since the torque is the required drive torque, the number of AC motors used for traveling is one, so that the ripple current can be reduced. Further, when the required drive torque is larger than the maximum torque that can be output from the first AC motor to the output shaft, the torque output from the first AC motor to the output shaft is set to be equal to or less than the maximum torque. Since the torque output from the second AC motor to the output shaft is the difference torque obtained by subtracting the limit torque from the required drive torque, the limit torque is set to an appropriate value. By doing so, the ripple current can be reduced.

1 is an overall configuration diagram illustrating an example of a vehicle on which a vehicle control device according to the present invention is mounted. It is a block diagram which shows an example of the motor drive control part shown in FIG. It is a block diagram which shows an example of a function structure of the control apparatus of the vehicle shown in FIG. It is a graph which shows an example of the characteristic of the limiting torque Tc set by the limiting torque setting part shown in FIG. It is a graph which shows an example of the relationship between a control system and an operation state in the two motors shown in FIG. 6 is a chart showing an example of a control method for two types of motors shown in FIG. 5. It is explanatory drawing of the control system of the motor shown in FIG. It is a graph which shows an example of the limiting torque Tc set by the limiting torque setting part shown in FIG. It is a graph which shows another example of the limiting torque Tc set by the limiting torque setting part shown in FIG. 4 is a flowchart showing an example of the operation of the vehicle control device shown in FIG. 3. It is a detailed flowchart which shows an example of the torque distribution process performed by step S113 of FIG. 12 is a chart showing an example of a result of torque distribution processing executed in the flowchart shown in FIG. 11.

  Embodiments of a “vehicle control apparatus” according to the present invention will be described below with reference to the drawings.

-Overall configuration of the vehicle-
First, an overall configuration of a vehicle (electric vehicle EV) on which a “vehicle control device” according to the present invention is mounted will be described with reference to FIG. FIG. 1 is an overall configuration diagram showing an example of a vehicle (electric vehicle EV) on which a vehicle control device according to the present invention is mounted. The electric vehicle EV includes an ECU 3, an accelerator pedal 5, motors M1 and M2, an output shaft 6, a differential gear 61, a drive shaft 62, driving wheels 63R and 63L, a battery 11, and motor drive control units 100 and 101. Yes. Here, the motor M1 corresponds to a “first AC motor” in the claims, and the motor M2 corresponds to a “second AC motor” in the claims.

  The ECU (Electronic Control Unit) 3 is an electronic control device that controls the operation of the motor drive control units 100 and 101 and the like, and includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), And a backup RAM and the like. The ECU 3 functions as a “vehicle control device” according to the present invention as will be described later with reference to FIG.

  The ROM stores various control programs, tables, maps, and the like that are referred to when the various control programs are executed. The CPU executes arithmetic processing based on various control programs, maps and the like stored in the ROM. The RAM is a memory for temporarily storing calculation results from the CPU, data input from each sensor, and the backup RAM is a non-volatile memory for storing data to be saved when the ignition switch is OFF. It is.

  The accelerator pedal 5 is a pedal that is stepped on by the driver when accelerating the electric vehicle EV, and is provided with an accelerator opening sensor 51. The accelerator opening sensor 51 is a sensor that detects the accelerator opening θ, and the detected accelerator opening θ is output to the ECU 3.

  The motors M1 and M2 are power sources for driving the electric vehicle EV, and are directly connected to the output shaft 6 here. Specifically, the motors M1 and M2 are AC motors, each including a rotor and a stator, and the rotors of the motors M1 and M2 are configured to be rotatable integrally with the output shaft 6, respectively. Torque output from the motors M1 and M2 is transmitted to the drive wheels 63R and 63L via the output shaft 6, the differential gear 61, and the drive shaft 62 sequentially. One end of the output shaft 6 is connected to the drive shaft 62, and the other end of the output shaft 6 is rotatably supported by a bearing 60. The motors M1 and M2 are configured to have both functions of an electric motor and a generator.

  Each of the motors M1 and M2 is provided with a rotation angle sensor (resolver) 25, and the rotation angle θ detected by the rotation angle sensor 25 is output to the ECU 3. Further, based on the rotation angle θ detected by the rotation angle sensor 25, the ECU 3 obtains the rotation speed RT and the angular speed ω (rad / s).

  The battery 11 supplies electric power to the motors M1 and M2 via the motor drive control unit 100 and the motor drive control unit 101, respectively, and includes, for example, a Li (lithium) ion battery. The battery 11 corresponds to a “storage battery” described in the claims.

  The motor drive control unit 100 and the motor drive control unit 101 control operations of the motor M1 and the motor M2, respectively, in accordance with instructions from the ECU 3. The configurations of the motor drive control unit 100 and the motor drive control unit 101 will be described below with reference to FIG.

  Since the motors M1 and M2 are directly connected to the output shaft 6 as described above, the outputs from the motors M1 and M2 are transmitted to the drive wheels 63R and 63L with a simple structure as shown in FIG. can do.

-Configuration of motor drive controller-
Next, the overall configuration of the motor drive control units 100 and 101 shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a configuration diagram illustrating an example of the motor drive control unit 100 (motor drive control unit 101) illustrated in FIG. Since the motor drive control unit 100 has substantially the same configuration as the motor drive control unit 101, the motor drive control unit 100 will be described here for convenience, and the description of the motor drive control unit 101 will be omitted. The motor drive control unit 100 includes a DC voltage generation unit 1α, a smoothing capacitor C0, and an inverter 13.

  The DC voltage generator 1α includes system relays SR1 and SR2 and a smoothing capacitor C1.

  System relay SR <b> 1 is interposed between the positive terminal of battery 11 and power line 42, and system relay SR <b> 2 is interposed between the negative terminal of battery 11 and power line 41. The voltage Vb of the battery 11 and the current Ib input / output to / from the battery 11 are detected by the voltage sensor 21 and the current sensor 22, respectively. Further, the temperature Tb of the battery 11 is detected by the temperature sensor 211. The detected voltage Vb, current Ib, and temperature Tb of the battery 11 are output to the ECU 3. System relays SR1 and SR2 are on / off controlled by a signal SE from ECU 3.

  The inverter 13 includes a U-phase upper and lower arm 131, a V-phase upper and lower arm 132, and a W-phase upper and lower arm 133, which are provided in parallel between the power line 43 and the power line 41, respectively. The upper and lower arms of each phase are each composed of a switching element connected in series between the power line 43 and the power line 41. For example, the U-phase upper and lower arms 131 are composed of switching elements Q3 and Q4, the V-phase upper and lower arms 132 are composed of switching elements Q5 and Q6, and the W-phase upper and lower arms 133 are composed of switching elements Q7 and Q8. It is configured. Diodes D3-D8 are connected in antiparallel to switching elements Q3-Q8, respectively. The switching elements Q3 to Q8 are turned on and off by switching control signals S3 to S8 from the ECU 3, respectively.

  The motor M1 is, for example, a three-phase permanent magnet synchronous motor, and is configured such that one end of three coils of a U phase, a V phase, and a W phase is commonly connected to a neutral point. The other end of each phase coil is connected to the intermediate point of the switching elements of the upper and lower arms 131 to 133, respectively.

  The smoothing capacitor C0 is a capacitor that smoothes the DC voltage from the battery 11 and supplies the smoothed DC voltage to the inverter 13. The voltage sensor 23 is a sensor that detects the voltage across the smoothing capacitor C0, that is, the system voltage VH, and outputs the detected value to the ECU 3.

  When the torque command value Trqα of the motor M1 is positive (Trqα> 0), the inverter 13 applies a DC voltage to the switching control signals S3 to S8 from the ECU 3 by the switching operations of the switching elements Q3 to Q8, respectively. The motor M1 is driven to convert the voltage into an AC voltage and output a positive torque. Further, when the torque command value Trqα of the motor M1 is “0” (Trqα = 0), the inverter 13 converts the DC voltage into the AC voltage by the switching operation in response to the switching control signals S3 to S8, and generates the torque. The motor M1 is driven to make it “0”. Thus, the motor M1 is driven to generate “0” designated by the torque command value Trqα or positive torque.

  Furthermore, during regenerative braking of a vehicle equipped with motor drive control unit 100, torque command value Trqα of motor M1 is set to be negative (Trqα <0). In this case, the inverter 13 converts the AC voltage generated by the motor M1 into a DC voltage by the switching operation in response to the switching control signals S3 to S8, and supplies the converted DC voltage to the battery 11. Here, “regenerative braking” means that the vehicle is decelerated (or acceleration is stopped) while regenerative power generation is performed by turning off the accelerator pedal 5 (see FIG. 1) while driving, although the foot brake is not operated. including.

  The current sensor 24 is a sensor that detects a motor current flowing through the motor M1, and outputs the detected value to the ECU 3. Since the sum of instantaneous values of the three-phase currents iu, iv, iw is “0”, the current sensor 24 detects motor currents for two phases (for example, V-phase current iv and W-phase current iw). May be arranged as follows.

  The rotation angle sensor (resolver) 25 is a sensor that detects the rotation angle θ of the rotor of the motor M1, and outputs the detected value to the ECU 3. The ECU 3 can calculate the rotational speed RT and the angular speed ω (rad / s) of the motor M1 based on the rotational angle θ.

  The ECU 3 includes, for example, a torque command value Trqα, a voltage Vb detected by the voltage sensor 21, a current Ib detected by the current sensor 22, a system voltage VH detected by the voltage sensor 23, a motor current iv from the current sensor 24, Based on iw, the rotation angle θ from the rotation angle sensor 25, and the like, the operation of the inverter 13 is controlled by the control method described later so that the motor M1 outputs torque according to the torque command value Trqα. That is, the ECU 3 generates switching control signals S <b> 3 to S <b> 8 for controlling the inverter 13 and outputs the switching control signals S <b> 3 to S <b> 8 to the inverter 13.

-Vehicle control device-
Next, the configuration of the “vehicle control device” according to the present invention will be described with reference to FIG. FIG. 3 is a block diagram showing an example of a functional configuration of the vehicle control device (ECU 3) shown in FIG. As shown in FIG. 3, the ECU 3 reads and executes a control program stored in the ROM or the like by the CPU, so that the required torque calculation unit 31, the limit torque setting unit 32, the torque determination unit 33, the torque It functions as functional units such as the distribution unit 34, the first motor characteristic storage unit 35, the second motor characteristic storage unit 36, the first motor control unit 37, and the second motor control unit 38. Further, the required torque calculation unit 31, the limit torque setting unit 32, the torque determination unit 33, the torque distribution unit 34, the first motor characteristic storage unit 35, the second motor characteristic storage unit 36, the first motor control unit 37, and The second motor control unit 38 constitutes a “vehicle control device” according to the present invention.

  The required torque calculation unit 31 is a functional unit that calculates “required drive torque T” based on the accelerator opening θ detected by the accelerator opening sensor 51. Here, “required drive torque T” is a drive torque that is requested to be output to the motors M1 and M2 of the electric vehicle EV when the driver depresses the accelerator pedal 5. For example, a lookup table (or map) that stores the accelerator opening θ and the required driving torque T in association with each other is provided, and the required torque calculation unit 31 includes the required driving torque T corresponding to the detected accelerator opening θ. Is read from the look-up table (or map) to obtain the required drive torque T.

-Setting method of limit torque Tc-
The limit torque setting unit 32 is a functional unit that sets “limit torque Tc”. Here, the “limit torque Tc” means that when the required drive torque T is greater than the maximum torque Tm1 that can be output from the motor M1 to the output shaft 6, the torque distribution unit 34 causes the motor M1 to output the shaft 6. This is the torque set as the output torque.

  Further, the limit torque setting unit 32 sets the limit torque Tc so as to reduce the ripple current superimposed on the current output from the battery 11. Specifically, the limit torque setting unit 32 determines the limit torque based on the temperature Tb of the battery 11, the remaining capacity SOC (State Of Charge) of the battery 11, the degree of deterioration of the battery 11, and the control method of the motor M1. Set Tc.

  The temperature Tb of the battery 11 is detected by a temperature sensor 211 (see FIG. 2). The remaining capacity SOC of the battery 11 is obtained, for example, in another ECU, and the limit torque setting unit 32 acquires the remaining capacity SOC of the battery 11 from the other ECU. Similarly, the degree of deterioration of the battery 11 (hereinafter also referred to as “degradation degree Db”) is obtained by, for example, another ECU, and the limit torque setting unit 32 receives the deterioration degree Db of the battery 11 from the other ECU. To get.

  Further, the remaining capacity SOC of the battery 11 can be obtained based on the voltage Vb of the battery 11 and the current Ib output from the battery 11, for example. The degree of deterioration Db of the battery 11 can be obtained based on, for example, the age of use of the battery 11.

  Here, an example of a method for setting the limit torque Tc by the limit torque setting unit 32 will be described with reference to FIGS. First, the relationship among the temperature Tb of the battery 11, the remaining capacity SOC of the battery 11, the deterioration degree Db of the battery 11, and the limit torque Tc will be described with reference to FIG. FIG. 4 is a graph showing an example of the characteristic of the limit torque Tc set by the limit torque setting unit 32 shown in FIG. FIG. 4A is a graph showing the relationship between the remaining capacity SOC of the battery 11 and the limit torque Tc, and FIG. 4B is a graph showing the relationship between the temperature Tb of the battery 11 and the limit torque Tc. FIG. 4C is a graph showing the relationship between the deterioration degree Db of the battery 11 and the limit torque Tc.

  As shown in FIG. 4A, the limit torque Tc is set smaller as the remaining capacity SOC of the battery 11 is larger. The reason is that as the remaining capacity SOC of the battery 11 increases, the internal resistance of the battery 11 decreases and the ripple current increases. Therefore, the limit torque Tc is reduced and the motor M1 is driven from one motor M1 earlier. This is because it is necessary to switch to the two-unit drive of M2.

  As shown in FIG. 4B, the limit torque Tc is set smaller as the temperature Tb of the battery 11 is higher. The reason is that, as the temperature Tb of the battery 11 is higher, the internal resistance of the battery 11 is smaller and the ripple current is larger. Therefore, the limit torque Tc is decreased, and the motor M1 This is because it is necessary to switch to the M2 dual drive.

  As shown in FIG. 4C, the limit torque Tc is set to be smaller as the deterioration degree Db of the battery 11 is smaller (deterioration is not progressing). The reason is that the smaller the deterioration level Db of the battery 11 (the more the deterioration does not progress), the smaller the internal resistance of the battery 11 and the larger the ripple current. This is because it is necessary to switch from the single drive to the two drive of the motors M1 and M2.

  As described above, since the limit torque Tc is set to reduce the ripple current superimposed on the current Ib output from the battery 11, the maximum torque that can be output from the motor M1 to the output shaft 6 by the required drive torque T. When it is larger than Tm1, ripple current can be reduced.

  Further, since the limit torque Tc is set based on the temperature Tb of the battery 11, the remaining capacity SOC of the battery 11, and the degree of deterioration of the battery 11, the limit torque Tc can be set to an appropriate value. Therefore, the ripple current can be reduced.

  In the present embodiment, the case where the limit torque Tc is set based on the temperature Tb of the battery 11, the remaining capacity SOC of the battery 11, and the degree of deterioration of the battery 11 will be described. 11 may be set based on at least one of the temperature Tb of 11, the remaining capacity SOC of the battery 11, and the degree of deterioration of the battery 11.

-Switching of control method in motors M1 and M2-
Next, the control method of the motors M1 and M2 will be described with reference to FIGS. FIG. 5 is a graph showing an example of the relationship between the control method and the operating state in the motors M1 and M2 shown in FIG. FIG. 5A is a graph showing an example of the relationship between the control method and the operation state in the motor M1 shown in FIG. FIG. 5B is a graph showing an example of the relationship between the control method and the operation state in the motor M2 shown in FIG. FIG. 6 is a chart showing an example of a control method for the two motors M1 and M2 shown in FIG. FIG. 7 is an explanatory diagram of a control method for the motors M1 and M2 shown in FIG.

  First, with reference to FIGS. 5 and 6, the relationship between the control method and the operation state in the motors M1 and M2 will be described. The horizontal axes of the graphs of FIGS. 5A and 5B are the rotational speeds of the motors M1 and M2, respectively, and the vertical axes are the torques of the motors M1 and M2, respectively. The graph G11 is a graph showing the maximum torque Tm1 of the motor M1, the graph G12 is a graph showing the maximum torque Tm2 of the motor M2, and the graph G13 is a maximum torque Tm1 of the motor M1 and the maximum torque of the motor M2. It is a graph which shows the sum (Tm1 + Tm2) with Tm2.

  Further, the lower region of the graph G11 shown in FIG. 5A, which is the control region of the motor M1, is divided into five regions R10 to R14. Similarly, the lower region of the graph G12 shown in FIG. 5B, which is the control region of the motor M2, is divided into four regions R21 to R24. Furthermore, the control method shown in FIG. 6 is set for each of the regions R10 to R14 and R21 to R24.

  That is, for the motor M1, the sine wave PWM control method is executed in the region R10 and the region R11 shown in FIG. 5A, the overmodulation PWM control method is executed in the region R12, and in the region R13 and the region R14, A rectangular wave voltage control method is executed. Note that the sine wave PWM control method in the region R10 and the sine wave PWM control method in the region R11 have different carrier frequencies. Specifically, the carrier frequency in the sine wave PWM control method in the region R10 is lower than the carrier frequency in the sine wave PWM control method in the region R11. In the high torque region shown in region R10, heating of inverter 13 (see FIG. 2) can be suppressed by using a low frequency carrier. As for the motor M2, the sine wave PWM control method is executed in the region R21, the region R22, and the region R23 shown in FIG. 5B, and the rectangular wave voltage control method is executed in the region R24.

  The first motor characteristic storage unit 35 shown in FIG. 3 stores the characteristics and control method of the motor M1 shown in FIG. 5A and FIG. 6, and the second motor characteristic storage unit 36 shown in FIG. Stores the characteristics and control method of the motor M2 shown in FIG. 5B and FIG.

  As shown in FIG. 5, the maximum torque Tm1 that can be output from the motor M1 is larger than the maximum torque Tm2 that can be output from the motor M2. Thus, since the maximum torque Tm1 that can be output from the motor M1 is greater than the maximum torque Tm2 that can be output from the motor M2, the required drive torque T can be output by only one motor (here, the motor M1). The range of possible demanded drive torque T can be expanded.

  Next, referring to FIG. 7, a control method used in the motors M1 and M2 will be described. The motor drive control unit 100 controls the motor M1, that is, the power conversion in the inverter 13, for the three types of control systems shown in FIG. 6 (sine wave PWM control system, overmodulation PWM control system, and rectangular wave voltage control system). Switch between and use. The motor drive control unit 101 switches between two types of control methods (sine wave PWM control method and rectangular wave voltage control method) shown in FIG. 6 for controlling the motor M2, that is, for power conversion in the inverter 13. To do.

-Features of each control method-
In the sine wave PWM control method, on / off of the upper and lower arm elements of each phase is controlled according to a voltage comparison between a sine wave voltage command and a carrier wave (for example, a triangular wave). As a result, for a set of a high level period corresponding to the on period of the upper arm element and a low level period corresponding to the on period of the lower arm element, the duty is set so that the fundamental wave component becomes a sine wave within a certain period. Is controlled. In this sine wave PWM control system in which the amplitude of the sinusoidal voltage command is limited to a range below the carrier wave amplitude, the fundamental wave component of the voltage applied to the motors M1 and M2 (hereinafter also referred to as “motor applied voltage”). Can only be increased up to A times the input voltage (where A is an upper limit value). Hereinafter, the ratio of the fundamental component (effective value) of the motor applied voltage (line voltage) to the input voltage of the inverter 13 (that is, the system voltage VH) is referred to as “modulation rate”.

  The overmodulation PWM control system performs PWM control similar to the sine wave PWM control system in a range where the amplitude of the voltage command (sine wave component) is larger than the carrier wave amplitude. In particular, the fundamental wave component can be increased by distorting the voltage command from the original sine wave waveform (amplitude correction), and the modulation rate can be increased from the maximum modulation rate to the upper limit range in the sine wave PWM control method. it can. In the overmodulation PWM control method, the voltage command (sinusoidal component) has a larger amplitude than the carrier wave amplitude, so the line voltage applied to the motor M1 is not a sine wave but a distorted voltage.

  On the other hand, in the rectangular wave voltage control method, one pulse of a rectangular wave with a ratio of 1: 1 between the high level period and the low level period is applied to the AC motor within the predetermined period. Thereby, in the rectangular wave voltage control method, the modulation rate is increased.

  In the motors M1 and M2, the induced voltage increases as the rotational speed and output torque increase, so that the required drive voltage (motor required voltage) increases. On the other hand, the system voltage VH has a limit value (VH maximum voltage). Therefore, the PWM control method by the sine wave PWM control method or the overmodulation PWM control method and the rectangular wave voltage control method are selectively applied according to the operation state of the motor M1, and according to the operation state of the motor M2. A sine wave PWM control method or a rectangular wave voltage control method is selectively applied. In the rectangular wave voltage control method, since the amplitude of the motor applied voltage is fixed, the phase of the rectangular wave voltage pulse based on the torque deviation (the difference between the actual torque value (estimated value) and the torque command value) with respect to the torque command value. Torque control is executed by the control. Moreover, since the switching method of a control system is well-known (for example, refer Unexamined-Japanese-Patent No. 2010-166707), the description is abbreviate | omitted here.

  As described above, the motor M1 is configured to be able to execute control by the three types of control methods of the sine wave pulse width modulation method, the pulse width overmodulation control method, and the rectangular wave voltage control method. Since an appropriate control method can be selected according to the output torque and rotational speed of the motor, the efficiency of the motor M1 can be improved.

  In the present embodiment, a case will be described in which the motor M1 is configured to be able to execute control by three types of control methods, a sine wave pulse width modulation method, a pulse width overmodulation control method, and a rectangular wave voltage control method. However, the motor M1 is configured to be able to execute control by at least two control methods among the three control methods of the sine wave pulse width modulation method, the pulse width overmodulation control method, and the rectangular wave voltage control method. Any form may be used.

-Example of limit torque Tc-
Next, an example of the limit torque Tc set by the limit torque setting unit 32 will be described with reference to FIGS. FIG. 8 is a graph showing an example of the limit torque Tc set by the limit torque setting unit 32 shown in FIG. FIG. 9 is a graph showing another example of the limit torque Tc set by the limit torque setting unit 32 shown in FIG. 8 and 9, graphs G21 to G23 indicating the limit torque Tc are shown so that the relationship with the control regions R10 to R14 of the motor M1 shown in FIG.

  A graph G21 showing the limit torque Tc shown in FIG. 8 is a graph showing the limit torque Tc set based on the relationship between the control method, operation state, and ripple current of the motor M1 shown in FIG. Here, for example, when the control state changes from the control region R11 to the region R10 shown in FIG. 5 (when the carrier frequency is low), the ripple current increases. Further, for example, when the control state changes from the control region R12 to the region R13 illustrated in FIG. 5 (when the control method changes from the overmodulation PWM control method to the rectangular wave voltage control method), the ripple current increases. Therefore, the graph G21 indicating the limit torque Tc shown in FIG. 8 sets the limit torque Tc so as not to cross the boundary line between the control region R11 and the region R10 and the boundary line between the control region R12 and the region R13. It is a thing.

  A graph G22 indicating the limit torque Tc in FIG. 9 and a graph G23 indicating the limit torque Tc in FIG. 9 are in addition to the relationship between the control method, operation state, and ripple current of the motor M1 shown in FIG. 4 is a graph showing the limit torque Tc set in consideration of the relationship between the temperature Tb of the battery 11, the remaining capacity SOC of the battery 11, and the degree of deterioration Db of the battery 11 and the ripple current described above with reference to FIG. is there.

  In FIG. 9, a graph G22 indicating the limit torque Tc is a graph showing the limit torque Tc set when the temperature Tb of the battery 11 is low and the remaining capacity SOC of the battery 11 is low. In addition, a graph G23 indicating the limit torque Tc in FIG. 9 is a graph showing the limit torque Tc set when the temperature Tb of the battery 11 is high and the remaining capacity SOC of the battery 11 is large.

  Here, as described above with reference to FIG. 4, the higher the temperature Tb of the battery 11 and the greater the remaining capacity SOC of the battery 11, the smaller the internal resistance of the battery 11 and the greater the ripple current. In the graph G23 shown in FIG. 9, compared with the graph G22 shown in FIG. 9, the limit torque Tc is reduced and the drive from one motor M1 to the two motors M1 and M2 is switched earlier. .

  As described above (particularly, as indicated by graph G21 in FIG. 8), the limit torque Tc is set based on the control method of the motor M1, so that the limit torque Tc can be set to a more appropriate value. Therefore, the ripple current can be further reduced.

-Torque distribution-
With reference to the block diagram shown in FIG. 3 again, the functional configuration of the ECU 3 will be described.

  The torque determination unit 33 is a functional unit that determines whether the required drive torque T obtained by the required torque calculation unit 31 is greater than the maximum torque Tm1 of the motor M1. The torque determination unit 33 is a functional unit that determines whether or not the required drive torque T obtained by the required torque calculation unit 31 is greater than the limit torque Tc set by the limit torque setting unit 32.

  The torque distribution unit 34 is a functional unit that distributes the required drive torque T to the motor M1 and the motor M2 based on the determination result of the torque determination unit 33. Specifically, the torque distribution unit 34 distributes the required drive torque T into the drive torque TR1 output from the motor M1 and the drive torque TR2 output from the motor M2 in the following manner.

  First, when the torque determination unit 33 determines that the required drive torque T is greater than the maximum torque Tm1 of the motor M1, the torque distribution unit 34 sets the drive torque TR1 output from the motor M1 to the limit torque. The drive torque TR2 output from the motor M2 is set to Tc, and is set to a differential torque obtained by subtracting the limit torque Tc from the request drive torque T (request drive torque T−limit torque Tc).

  When the torque determination unit 33 determines that the required drive torque T is equal to or less than the limit torque Tc, the torque distribution unit 34 sets the drive torque TR1 output from the motor M1 as the required drive torque T. Then, the drive torque TR2 output from the motor M2 is set to “0”. In this case, the required drive torque T is output only by the motor M1.

  Further, when the torque determination unit 33 determines that the required drive torque T is equal to or less than the maximum torque Tm1 of the motor M1 and greater than the limit torque Tc, the torque distribution unit 34 Based on whether or not the driving torque TR1 output from the motor M1 was the required driving torque T in the previous processing of the allocating unit 34, the required driving torque T is output from the motor M1 and the motor M2 It distributes to drive torque TR2 to output.

  If the drive torque TR1 output from the motor M1 is the required drive torque T in the previous processing of the torque distribution unit 34, the torque distribution unit 34 uses the drive torque TR1 output from the motor M1 as the required drive torque. The driving torque TR2 output from the motor M2 is set to “0”. In this case, the required drive torque T is output only by the motor M1.

  If the drive torque TR1 output from the motor M1 is not the required drive torque T in the previous processing of the torque distribution unit 34, the torque distribution unit 34 sets the drive torque TR1 output from the motor M1 to the limit torque Tc. And the drive torque TR2 output from the motor M2 is set to a differential torque obtained by subtracting the limit torque Tc from the request drive torque T (request drive torque T−limit torque Tc).

  In this way, the torque distribution unit 34 outputs the required drive torque T from the motor M1 based on whether or not the drive torque TR1 output from the motor M1 was the required drive torque T in the previous process. Since the torque TR1 and the driving torque TR2 output from the motor M2 are distributed, so-called hysteresis characteristics can be provided, so that the driving torque TR1 and the driving torque TR2 can be stably changed according to the change in the required driving torque T. Can be determined.

  The first motor control unit 37 is a functional unit that outputs an instruction signal to the motor drive control unit 100 so as to output the drive torque TR1 set by the torque distribution unit 34 from the motor M1.

  The second motor control unit 38 is a functional unit that outputs an instruction signal to the motor drive control unit 101 so as to output the drive torque TR2 set by the torque distribution unit 34 from the motor M2.

-ECU operation-
Next, the operation of the ECU 3 will be described with reference to FIGS. FIG. 10 is a flowchart showing an example of the operation of the vehicle control device (ECU 3) shown in FIG. FIG. 11 is a detailed flowchart showing an example of torque distribution processing executed in step S113 of FIG. As shown in FIG. 10, first, the required torque calculation unit 31 acquires the accelerator opening θ from the accelerator opening sensor 51 (step S101). Then, the required torque calculation unit 31 calculates the required drive torque T based on the accelerator opening degree θ acquired in step S101 (step S103).

  Next, the temperature Tb of the battery 11 is acquired by the limit torque setting unit 32 (step S105). Then, the remaining capacity SOC of the battery 11 is acquired by the limit torque setting unit 32 (step S107). Next, the deterioration degree Db of the battery 11 is acquired by the limit torque setting unit 32 (step S109). Next, based on the temperature Tb of the battery 11 acquired in step S105, the remaining capacity SOC of the battery 11 acquired in step S107, and the deterioration degree Db of the battery 11 acquired in step S109 by the limit torque setting unit 32. Thus, the limit torque Tc is set (step S111).

  Then, a “torque distribution process” that is a process of distributing the required drive torque T obtained in step S103 to the motor M1 and the motor M2 is executed by the torque distribution unit 34 or the like (step S113). The “torque distribution process” will be described later with reference to FIG. Next, the first motor control unit 37 instructs the motor drive control unit 100 to determine the drive torque TR1 of the motor M1 determined in the “torque distribution process” (step S115). Next, the second motor control unit 38 instructs the motor drive control unit 101 to determine the drive torque TR2 of the motor M2 determined in the “torque distribution process” (step S117), and the process returns to step S101. Then, the processing after step S101 is repeatedly executed.

-Torque distribution processing-
Here, with reference to FIG. 11, the operation of the ECU 3 in the “torque distribution process” will be described. First, the torque determination unit 33 determines whether or not the required drive torque T obtained in step S103 in FIG. 10 is greater than the maximum torque Tm1 of the motor M1 (step S201). If YES in step S201, the process proceeds to step S203. If NO in step S201, the process proceeds to step S205.

  If YES in step S201, the torque distribution unit 34 sets the drive torque TR1 of the motor M1 to the limit torque Tc, and the drive torque TR2 of the motor M2 is the difference torque obtained by subtracting the limit torque Tc from the required drive torque T. (Requested drive torque T−Limit torque Tc) is set (step S203), and the process is returned to step S115 in FIG.

  In the case of NO in step S201, it is determined whether or not the required drive torque T obtained in step S103 of FIG. 10 by the torque determination unit 33 is smaller than the limit torque Tc set in step S111 of FIG. A determination is made (step S205). If YES in step S205, the process proceeds to step S207. If NO in step S205, the process proceeds to step S209.

  If YES in step S205, the torque distribution unit 34 sets the drive torque TR1 of the motor M1 to the required drive torque T, and sets the drive torque TR2 of the motor M2 to “0” (step S207). The process returns to step S115 in FIG.

  If NO in step S205, the torque distribution unit 34 determines whether or not the drive torque TR1 output from the motor M1 was the required drive torque T in the previous “torque distribution process” (step S205). S209). If YES in step S209, the process proceeds to step S211. If NO in step S209, the process proceeds to step S213.

  If YES in step S209, the torque distribution unit 34 sets the drive torque TR1 of the motor M1 to the required drive torque T, and sets the drive torque TR2 of the motor M2 to “0” (step S211). The process returns to step S115 in FIG.

  In the case of NO in step S209, the torque distribution unit 34 sets the drive torque TR1 of the motor M1 to the limit torque Tc, and the drive torque TR2 of the motor M2 is the difference torque obtained by subtracting the limit torque Tc from the required drive torque T. (Required drive torque T−limit torque Tc) is set (step S213), and the process returns to step S115 in FIG.

  As described above, when the required drive torque T is equal to or less than the maximum torque Tm1 that can be output from the motor M1, the drive torque TR1 output from the motor M1 is the required drive torque T. Since the number is one (here, only the motor M1), the ripple current can be reduced. When the required drive torque T is greater than the maximum torque Tm1 that can be output from the motor M1, the drive torque TR1 output from the motor M1 is set to the limit torque Tc set to be equal to or less than the maximum torque Tm1, and the motor M2 Since the output drive torque TR2 is the difference torque (required drive torque T−limit torque Tc) obtained by subtracting the limit torque Tc from the required drive torque T, the ripple is set by setting the limit torque Tc to an appropriate value. The current can be reduced.

-Results of torque distribution processing-
Finally, an example of the result of the torque distribution process will be described with reference to FIGS. 8 and 12. FIG. 12 is a chart showing an example of a result of “torque distribution processing” executed in the flowchart shown in FIG. FIG. 12 shows an example of the result of the torque distribution process when the limit torque Tc is the graph G21 shown in FIG. 8, and FIG. 8 shows the result at the point P1 and the end point at the point P7. The points P1 to P7 are shown.

  The first row of the chart shown in FIG. 12 is a reference sign of the points P1 to P7, and the second row is the drive torque TR1 of the motor M1 and the drive torque of the motor M2 corresponding to the points P1 to P7, respectively. TR2 is a step number indicating at which step of the flowchart shown in FIG. The third and fourth rows of the chart shown in FIG. 12 are the driving torque TR1 of the motor M1 and the driving torque TR2 of the motor M2, respectively.

  First, at the point P1 shown in FIG. 8, the required drive torque T is equal to or less than the limit torque Tc. Therefore, the drive torque TR1 is set to the required drive torque T and the drive torque TR2 is “ 0 "is set. Next, at the point P2 shown in FIG. 8, the required drive torque T is greater than the limit torque Tc, is equal to or less than the maximum torque Tm1, and is output from the motor M1 in the “torque distribution process” at the previous point P1. Since the requested drive torque TR1 is the requested drive torque T, the drive torque TR1 is set to the requested drive torque T and the drive torque TR2 is set to “0” in step S211 of the flowchart shown in FIG.

  Then, at the point P3 shown in FIG. 8, similarly to the point P2, the required drive torque T is greater than the limit torque Tc, is equal to or less than the maximum torque Tm1, and “torque distribution processing” at the previous point P2 is performed. In step S211 of the flowchart shown in FIG. 11, the drive torque TR1 is set to the required drive torque T and the drive torque TR2 is set to “0” because the drive torque TR1 output from the motor M1 in FIG. Is done. Next, at the point P4 shown in FIG. 8, the required drive torque T is larger than the maximum torque Tm1, and in step S203 of the flowchart shown in FIG. 11, the drive torque TR1 is set to the limit torque Tc, and the drive torque TR2 is A difference torque obtained by subtracting the limit torque Tc from the request drive torque T (request drive torque T−limit torque Tc) is set.

  Next, at the point P5 shown in FIG. 8, the required drive torque T is greater than the limit torque Tc, is equal to or less than the maximum torque Tm1, and is output from the motor M1 in the “torque distribution process” at the previous point P4. 11 is not the required drive torque T, the drive torque TR1 is set to the limit torque Tc in step S213 of the flowchart shown in FIG. 11, and the drive torque TR2 subtracts the limit torque Tc from the request drive torque T. The differential torque (required drive torque T−limit torque Tc) is set. Next, at the point P6 shown in FIG. 8, similarly to the point P5, the required drive torque T is greater than the limit torque Tc, is equal to or less than the maximum torque Tm1, and “torque distribution process” at the previous point P5. In step S213 of the flowchart shown in FIG. 11, the drive torque TR1 is set to the limit torque Tc, and the drive torque TR2 is changed from the required drive torque T because the drive torque TR1 output from the motor M1 in FIG. The differential torque obtained by subtracting the limit torque Tc (required drive torque T−limit torque Tc) is set.

  Then, at the point P7 shown in FIG. 8, the required drive torque T is equal to or less than the limit torque Tc. Therefore, the drive torque TR1 is set to the required drive torque T in step S207 of the flowchart shown in FIG. 0 "is set. Thus, according to the change in the required drive torque T, the drive torque TR1 output from the motor M1 and the drive torque TR2 output from the motor M2 are set according to the flowchart shown in FIG.

-Other embodiments-
In the present embodiment, a required torque calculation unit 31, a limit torque setting unit 32, a torque determination unit 33, a torque distribution unit 34, a first motor characteristic storage unit 35, and a second motor characteristic storage that constitute a “vehicle control device”. Although the case where the part 36, the 1st motor control part 37, and the 2nd motor control part 38 are comprised as a function part is demonstrated, the request | requirement torque calculation part 31, the limit torque setting part 32, the torque determination part 33, torque At least one of the distribution unit 34, the first motor characteristic storage unit 35, the second motor characteristic storage unit 36, the first motor control unit 37, and the second motor control unit 38 is configured by hardware such as an electronic circuit. It may be a form.

  In the present embodiment, the case where the vehicle is the electric vehicle EV has been described. However, the vehicle may be a so-called hybrid vehicle that includes an internal combustion engine such as an engine in addition to the motors M1 and M2 as a driving source for traveling. .

  In the present embodiment, the case where the vehicle (electric vehicle EV) includes two motors M1 and M2 has been described, but the vehicle (electric vehicle EV) may include three or more motors. In this case, according to the technical idea of the present invention, the ripple current can be suppressed by driving sequentially from the motor having the largest maximum torque.

  In the present embodiment, the case where the motors M1 and M2 are each directly connected to the output shaft 6 will be described. However, at least one of the motors M1 and M2 may not be directly connected to the output shaft 6. For example, between the motors M1 and M2 and the output shaft 6, gears or the like for converting (decelerating or accelerating) the rotational speeds are arranged according to the characteristics such as the maximum rotational speeds of the motors M1 and M2. It may be a form.

  In the present embodiment, the case where the motor drive control units 100 and 101 do not include the boost converter has been described. However, the motor drive control units 100 and 101 may include a boost converter between the battery 11 and the inverter 13. Good (see FIG. 2).

  The present invention can be used in a control device for a vehicle including a first AC motor and a second AC motor that are driving power sources.

EV Electric vehicle (vehicle)
DESCRIPTION OF SYMBOLS 100, 101 Motor drive control part 1 (alpha) DC voltage generation part 11 Battery 13 Inverter 21 Voltage sensor 211 Temperature sensor 22 Current sensor 23 Voltage sensor 24 Current sensor 25 Rotation angle sensor 3 ECU (vehicle control apparatus)
31 Request torque calculation unit 32 Limit torque setting unit 33 Torque determination unit 34 Torque distribution unit 35 First motor characteristic storage unit 36 Second motor characteristic storage unit 37 First motor control unit 38 Second motor control unit 5 Accelerator pedal 51 Accelerator Opening sensor 6 Output shaft 61 Differential gear 62 Drive shaft 63R, 63L Drive wheel M1 motor (first AC motor)
M2 motor (second AC motor)
T Required drive torque Tc Limit torque Tm1 Maximum torque of motor M1 Tm2 Maximum torque of motor M2 TR1 Drive torque of motor M1 TR2 Drive torque of motor M2

Claims (7)

A first AC motor and a second AC motor which are driving power sources;
A vehicle control device comprising: an output shaft that transmits driving torque to wheels;
When the required drive torque is equal to or less than the maximum torque that can be output from the first AC motor to the output shaft, the torque output from the first AC motor to the output shaft is set as the required drive torque,
When the required drive torque is greater than the maximum torque that can be output from the first AC motor to the output shaft, the torque that is output from the first AC motor to the output shaft is set to be equal to or less than the maximum torque. A vehicle control device characterized in that the torque output from the second AC motor to the output shaft is a torque obtained by subtracting the limit torque from the required drive torque. The vehicle control device according to claim 1,
A storage battery for supplying power to the first AC motor and the second AC motor;
The vehicle control apparatus, wherein the limit torque is set so as to reduce a ripple current superimposed on a current output from the storage battery. The vehicle control device according to claim 2,
The vehicle control apparatus, wherein the limit torque is set based on at least one of a temperature of the storage battery, a remaining capacity of the storage battery, and a degree of deterioration of the storage battery. In the vehicle control device according to claim 2 or 3,
The first AC motor has three types of control: a sine wave pulse width modulation method, a pulse width overmodulation control method in which the amplitude of the fundamental wave component is larger than the sine wave pulse width modulation method, and a rectangular wave voltage control method. A vehicle control device configured to be able to execute control by at least two types of control methods. , The vehicle control device according to claim 4,
The vehicle control device, wherein the limit torque is set based on the control method of the first AC motor. In the vehicle control device according to any one of claims 1 to 5,
The maximum torque that can be output from the first AC motor to the output shaft is greater than the maximum torque that can be output from the second AC motor to the output shaft. The vehicle control device according to any one of claims 1 to 6,
The first AC motor and the second AC motor are directly connected to the output shaft, respectively.

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