JP2006211789A - Power output apparatus, automobile equipped with the same, and control method of power output apparatus - Google Patents

Abstract

To further suppress overdischarge of a battery.
SOLUTION: In an automobile having an engine, a motor MG1 and a drive shaft connected to a planetary gear mechanism and a motor MG2 connected to the drive shaft and having a battery capable of exchanging electric power with the motors MG1 and MG2, between the terminals of the battery When the voltage Vb is lower than the target lower limit voltage Vbmin set to increase as the internal resistance R increases (S160), the output limit correction value ΔWout is set using the inter-terminal voltage Vb and the target lower limit voltage Vbmax ( S180), an output allowable limit Woutf is set using the battery output limit Wout and the output limit correction value ΔWout (S190), and a torque command Tm2 * of the motor MG2 is set using the output allowable limit Woutf (S200 to S200). S220). As a result, the motor MG2 can be controlled in consideration of the internal resistance R, and the overdischarge of the battery can be further suppressed.
[Selection] Figure 2

Description

  The present invention relates to a power output apparatus, an automobile equipped with the power output apparatus, and a method for controlling the power output apparatus.

Conventionally, as this type of power output device, a device that is mounted on an automobile including an engine capable of outputting power to an axle, a generator connected to the engine, and a battery that is charged by power generation by the generator is proposed. (For example, refer to Patent Document 1). In this device, the power generation performance of the internal combustion engine is set by setting a target power generation voltage corresponding to the operation state, the battery state, etc., and generating power by the generator so that the battery voltage detected by the voltage detection means approaches the target power generation voltage. And low fuel consumption.
JP 7-39083 A

  However, the above-described power output apparatus does not consider the internal resistance of the battery. When the internal resistance is large, such as when the temperature of the battery is low, the voltage drop at the time of discharging becomes large, which may cause overdischarge of the battery.

  The power output device of the present invention, the automobile on which the power output device is mounted, and the control method of the power output device are aimed at further suppressing overdischarge of the power storage device. Another object of the power output device of the present invention, a vehicle equipped with the power output device, and a method for controlling the power output device is to further suppress overcharging of the power storage device.

  In order to achieve at least a part of the above object, the power output apparatus of the present invention, the automobile equipped with the power output apparatus, and the control method of the power output apparatus employ the following means.

The power output apparatus of the present invention is
A power output device that outputs power to a drive shaft,
An internal combustion engine;
Power generation means capable of generating power using power from the internal combustion engine;
An electric motor capable of inputting and outputting power to the drive shaft;
Power storage means capable of exchanging electric power with the power generation means and the electric motor,
Required driving force setting means for setting required driving force to be output to the driving shaft;
Voltage detection means for detecting the voltage of the power storage means;
Internal resistance estimating means for estimating the internal resistance of the power storage means;
Target lower limit voltage setting means for setting a target lower limit voltage based on the estimated internal resistance of the power storage means;
When the driving force based on the set required driving force is output to the drive shaft and the detected voltage of the power storage means is lower than the set target lower limit voltage, the voltage of the power storage means is equal to or higher than the target lower limit voltage. Control means for controlling the internal combustion engine, the power generation means and the electric motor to be
It is a summary to provide.

  In the power output apparatus of the present invention, the driving force based on the required driving force to be output to the drive shaft is output to the drive shaft, and the voltage of the power storage means is less than the target lower limit voltage set based on the internal resistance of the power storage means. When the voltage is low, the internal combustion engine, the power generation means, and the motor are controlled so that the voltage of the power storage means becomes equal to or higher than the target lower limit voltage. Therefore, by using the target lower limit voltage set based on the internal resistance of the power storage means, overdischarge of the power storage means can be further suppressed. Of course, the driving force based on the required driving force can be output to the drive shaft.

  In such a power output apparatus of the present invention, the target lower limit voltage setting means may be means for setting the target lower limit voltage so as to increase as the estimated internal resistance of the power storage means increases. In this way, the target lower limit voltage can be set more appropriately. In the power output apparatus of the present invention, when the detected voltage of the power storage means is lower than the set target lower limit voltage, the control means is based on a deviation between the voltage of the power storage means and the target lower limit voltage. Thus, it may be a means for controlling in a direction in which the deviation is canceled.

  The power output apparatus according to the present invention further includes temperature detection means for detecting the temperature of the power storage means, and the internal resistance estimation means estimates the internal resistance of the power storage means based on the detected temperature of the power storage means. It can also be a means. In this case, the internal resistance estimating means may be means for estimating the internal resistance of the power storage means so as to increase as the detected temperature of the power storage means decreases. In this way, the internal resistance of the power storage means can be estimated more appropriately.

  Further, in the power output apparatus of the present invention, the control means allows the output from the power storage means to limit the output of the power storage means when the detected voltage of the power storage means is not less than the set target lower limit voltage. When the detected voltage of the power storage means is lower than the set target lower limit voltage, a correction value is set based on the voltage of the power storage means and the target lower limit voltage, and the power storage means Based on the output limit and the set correction value, an output allowable limit that allows output from the power storage means is set, and the electric motor is set based on the set required driving force and the set output allowable limit. The drive command may be set and the motor may be controlled to be driven based on the set drive command.

  In the power output apparatus of the present invention, the power output device further includes target upper limit voltage setting means for setting the target upper limit voltage so that the larger the internal resistance of the power storage means is, the control means has the detected voltage of the power storage means When the voltage is higher than the set target upper limit voltage, it may be a means for controlling the voltage of the power storage means to be equal to or lower than the target upper limit voltage. In this way, overcharging of the power storage means can be further suppressed.

  In the power output apparatus of the present invention, the power generation means is connected to the output shaft and the drive shaft of the internal combustion engine, and at least part of the power from the internal combustion engine is accompanied by input and output of power and power. It may be an electric power input / output means for outputting to the drive shaft. In this case, the electric power drive input / output means has three shafts, that is, an output shaft of the internal combustion engine, the drive shaft, and a rotation shaft, and is based on the power input / output to / from any two of the three shafts. It is also possible to use a three-axis power input / output means for inputting / outputting power to / from the shaft and a generator capable of inputting / outputting power to / from the rotary shaft, or to the output shaft of the internal combustion engine. A counter-rotor electric motor having a connected first rotor and a second rotor connected to the drive shaft, wherein the first rotor and the second rotor rotate relatively It can also be assumed.

  The automobile of the present invention is a power output apparatus of the present invention according to any one of the above-described aspects, that is, basically a power output apparatus that outputs power to a drive shaft, and includes an internal combustion engine and an output from the internal combustion engine. Power generation means capable of generating power using power, an electric motor capable of inputting / outputting power to / from the drive shaft, power storage means capable of exchanging power with the power generation means and the motor, and requested drive to be output to the drive shaft Based on the required driving force setting means for setting the force, voltage detection means for detecting the voltage of the power storage means, internal resistance estimation means for estimating the internal resistance of the power storage means, and the estimated internal resistance of the power storage means Target lower limit voltage setting means for setting the target lower limit voltage, and a driving force based on the set required driving force is output to the drive shaft, and the detected voltage of the power storage means is the set target lower limit voltage. Than A power output device comprising a control means for controlling the internal combustion engine, the power generation means and the electric motor so that the voltage of the power storage means is equal to or higher than the target lower limit voltage, and the axle is connected to the drive shaft The gist of this is

  In this automobile of the present invention, since the power output device of the present invention according to any one of the above aspects is mounted, the effect of the power output device of the present invention, for example, the effect of further suppressing the overdischarge of the power storage means. The same effects as those described above can be obtained.

  In such an automobile according to the present invention, the internal resistance estimation means is configured such that the power storage means is based on at least one of a temperature of the power storage means, a travel distance of the vehicle, and a time after the power storage means is installed in the vehicle. It can also be a means for estimating the internal resistance. In this way, the internal resistance of the power storage means can be estimated more appropriately.

The method for controlling the power output apparatus of the present invention includes:
An internal combustion engine, power generation means capable of generating power using power from the internal combustion engine, an electric motor capable of inputting / outputting power to / from the drive shaft, power storage means capable of exchanging electric power with the power generation means and the motor, A method for controlling a power output device comprising:
(A) setting a required driving force to be output to the driving shaft;
(B) detecting the voltage of the power storage means;
(C) estimating an internal resistance of the power storage means;
(D) setting a target lower limit voltage based on the estimated internal resistance of the power storage means;
(E) When a driving force based on the set required driving force is output to the drive shaft and the detected voltage of the power storage means is lower than the set target lower limit voltage, the voltage of the power storage means is set to the target The gist is to control the internal combustion engine, the power generation means, and the electric motor so as to be equal to or higher than a lower limit voltage.

  According to the control method of the power output apparatus of the present invention, the driving force based on the required driving force to be output to the drive shaft is output to the drive shaft, and the voltage of the power storage unit is set based on the internal resistance of the power storage unit. When the voltage is lower than the target lower limit voltage, the internal combustion engine, the power generation means, and the motor are controlled so that the voltage of the power storage means becomes equal to or higher than the target lower limit voltage, so by using the target lower limit voltage set based on the internal resistance of the power storage means The overdischarge of the power storage means can be further suppressed. Of course, the driving force based on the required driving force can be output to the drive shaft.

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 equipped with a power output apparatus as an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a three-shaft power distribution / integration mechanism 30 connected to a crankshaft 26 as an output shaft of the engine 22 via a damper 28, and power distribution / integration. A motor MG1 capable of generating electricity connected to the mechanism 30, a motor MG2 connected to the power distribution and integration mechanism 30 via a reduction gear 35, and a hybrid electronic control unit 70 for controlling the entire vehicle are provided.

  The engine 22 is an internal combustion engine that outputs power using a hydrocarbon-based fuel such as gasoline or light oil, and an engine electronic control unit (hereinafter referred to as an engine ECU) that receives signals from various sensors that detect the operating state of the engine 22. ) 24 is subjected to operation control such as fuel injection control, ignition control, intake air amount adjustment control and the like. The engine ECU 24 is in communication with the hybrid electronic control unit 70, controls the operation of the engine 22 by a control signal from the hybrid electronic control unit 70, and, if necessary, transmits data related to the operating state of the engine 22 to the hybrid electronic control. Output to unit 70.

  The power distribution and integration mechanism 30 includes an external gear sun gear 31, an internal gear ring gear 32 arranged concentrically with the sun gear 31, a plurality of pinion gears 33 that mesh with the sun gear 31 and mesh with the ring gear 32, A planetary gear mechanism is provided that includes a carrier 34 that holds a plurality of pinion gears 33 so as to rotate and revolve, and that performs differential action using the sun gear 31, the ring gear 32, and the carrier 34 as rotational elements. In the power distribution and integration mechanism 30, the crankshaft 26 of the engine 22 is connected to the carrier 34, the motor MG1 is connected to the sun gear 31, and the reduction gear 35 is connected to the ring gear 32 via the ring gear shaft 32a. When functioning as a generator, power from the engine 22 input from the carrier 34 is distributed according to the gear ratio between the sun gear 31 side and the ring gear 32 side, and when the motor MG1 functions as an electric motor, the engine input from the carrier 34 The power from 22 and the power from the motor MG1 input from the sun gear 31 are integrated and output to the ring gear 32 side. The power output to the ring gear 32 is output from the ring gear shaft 32a to the drive wheels 39a and 39b via the gear mechanism 37 and the differential gear 38.

  Both the motor MG1 and the motor MG2 are configured as well-known synchronous generator motors that can be driven as generators and can be driven as motors, and exchange power with the battery 50 via inverters 41 and 42. The power line 54 connecting the inverters 41 and 42 and the battery 50 is configured as a positive and negative bus shared by the inverters 41 and 42, and the electric power generated by one of the motors MG 1 and MG 2 is supplied to another motor. It can be consumed at. Therefore, battery 50 is charged / discharged by electric power generated from motors MG1 and MG2 or insufficient electric power. Note that the battery 50 is not charged / discharged if the electric power balance is balanced by the motor MG1 and the motor MG2. Both the motors MG1 and MG2 are driven and controlled by a motor electronic control unit (hereinafter referred to as a motor ECU) 40. The motor ECU 40 detects signals necessary for driving and controlling the motors MG1 and MG2, such as signals from rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2, and current sensors (not shown). The phase current applied to the motors MG1 and MG2 to be applied is input, and a switching control signal to the inverters 41 and 42 is output from the motor ECU 40. The motor ECU 40 calculates the rotational speeds Nm1 and Nm2 of the rotors of the motors MG1 and MG2 by a rotational speed calculation routine (not shown) based on signals input from the rotational position detection sensors 43 and 44. The motor ECU 40 is in communication with the hybrid electronic control unit 70, controls the driving of the motors MG1 and MG2 by a control signal from the hybrid electronic control unit 70, and, if necessary, data on the operating state of the motors MG1 and MG2. Output to the hybrid electronic control unit 70.

  The battery 50 is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 52. The battery ECU 52 receives signals necessary for managing the battery 50, for example, an inter-terminal voltage Vb from the voltage sensor 51 a installed between the terminals of the battery 50, and a power line 54 connected to the output terminal of the battery 50. The charging / discharging current from the attached current sensor 51b, the battery temperature Tb from the temperature sensor 51c attached to the battery 50, and the like are input, and data on the state of the battery 50 is electronically controlled by communication as necessary. Output to unit 70. The battery ECU 52 also calculates the remaining capacity (SOC) based on the integrated value of the charge / discharge current detected by the current sensor in order to manage the battery 50.

  The hybrid electronic control unit 70 is configured as a microprocessor centered on the CPU 72. In addition to the CPU 72, a ROM 74 that stores processing programs, a RAM 76 that temporarily stores data, an input / output port and communication (not shown), and the like. And a port. The hybrid electronic control unit 70 is provided with an ignition signal from the ignition switch 80, a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator opening Acc corresponding to the amount of depression of the accelerator pedal 83. Acceleration opening degree Acc from the accelerator pedal position sensor 84 to be detected, brake pedal position BP from the brake pedal position sensor 86 to detect the depression amount of the brake pedal 85, vehicle speed V from the vehicle speed sensor 88, travel from the odometer 89 A distance L or the like is input via the input port. As described above, the hybrid electronic control unit 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via communication ports, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. Is doing.

  The hybrid vehicle 20 of the embodiment thus configured calculates the required torque to be output to the ring gear shaft 32a as the drive shaft based on the accelerator opening Acc and the vehicle speed V corresponding to the depression amount of the accelerator pedal 83 by the driver. Then, the operation of the engine 22, the motor MG1, and the motor MG2 is controlled so that the required power corresponding to the required torque is output to the ring gear shaft 32a. As operation control of the engine 22, the motor MG1, and the motor MG2, the operation of the engine 22 is controlled so that power corresponding to the required power is output from the engine 22, and all of the power output from the engine 22 is the power distribution and integration mechanism 30. Torque conversion operation mode for driving and controlling the motor MG1 and the motor MG2 so that the torque is converted by the motor MG1 and the motor MG2 and output to the ring gear shaft 32a, and the required power and the power required for charging and discharging the battery 50. The engine 22 is operated and controlled so that suitable power is output from the engine 22, and all or part of the power output from the engine 22 with charging / discharging of the battery 50 is the power distribution and integration mechanism 30, the motor MG1, and the motor. The required power is converted to the ring gear shaft 32 with torque conversion by MG2. Charge / discharge operation mode in which the motor MG1 and the motor MG2 are driven and controlled to be output to each other, and a motor operation mode in which the operation of the engine 22 is stopped and the power corresponding to the required power from the motor MG2 is output to the ring gear shaft 32a. and so on.

  Next, the operation of the hybrid vehicle 20 configured as described above will be described. FIG. 2 is a flowchart showing an example of a drive control routine executed by the hybrid electronic control unit 70. This routine is executed every predetermined time (for example, every several milliseconds).

  When the drive control routine is executed, first, the CPU 72 of the hybrid electronic control unit 70 first determines the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 88, the rotational speed Nm1, of the motors MG1, MG2. Nm2, the inter-terminal voltage Vb of the battery 50, the battery temperature Tb of the battery 50, the charge / discharge required power Pb * to be charged / discharged by the battery 50, the input / output restrictions Win and Wout of the battery 50, etc. (Step S100). Here, the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are input from the motor ECU 40 by communication from those calculated based on the rotational positions of the rotors of the motors MG1 and MG2 detected by the rotational position detection sensors 43 and 44. To do. The terminal voltage Vb and the battery temperature Tb are detected by the voltage sensor 51a and the temperature sensor 51c and input from the battery ECU 52 by communication. The charge / discharge required power Pb * is set based on the remaining capacity (SOC) of the battery 50 and the like, and is input from the battery ECU 52 by communication. The charge / discharge request power Pb * is set so that the discharge request is on the positive side and the charge request is on the negative side. The input / output limits Win and Wout of the battery 50 set basic values of the input / output limits Win and Wout based on the battery temperature, and the output limit correction coefficient and the input limit correction based on the remaining capacity (SOC) of the battery 50. Coefficients are set, and the basic values of the set input / output limits Win and Wout are multiplied by the correction coefficient to set the input / output limits Win and Wout, and input from the battery ECU 52 by communication. FIG. 3 shows an example of the relationship between the battery temperature Tb and the input / output limits Win, Wout, and FIG. 4 shows an example of the relationship between the remaining capacity (SOC) of the battery 50 and the correction coefficients of the input / output limits Win, Wout.

  When the data is input in this way, the required torque Tr * to be output to the ring gear shaft 32a as the drive shaft and the required power Pe * required for the engine 22 are set based on the input accelerator opening Acc and the vehicle speed V ( Step S110). In the embodiment, the required torque Tr * is determined in advance by storing the relationship between the accelerator opening Acc, the vehicle speed V, and the required torque Tr * in the ROM 74 as a required torque setting map, and the accelerator opening Acc, the vehicle speed V, , The corresponding required torque Tr * is derived and set from the stored map. FIG. 5 shows an example of the required torque setting map. The required power Pe * is calculated by the following equation (1) using the required torque Tr * multiplied by the rotation speed Nr of the ring gear shaft 32a, the charge / discharge required power Pb * to be charged / discharged by the battery 50, and the loss Loss. To do. The rotational speed Nr of the ring gear shaft 32a can be obtained by dividing the rotational speed Nm2 of the motor MG2 by the gear ratio Gr of the reduction gear 35, or by multiplying the vehicle speed V by the conversion factor k.

  Pe * = Tr * ・ Nm2 / Gr-Pb * + Loss… (1)

  Subsequently, the target rotational speed Ne * and the target torque Te * of the engine 22 are set based on the required power Pe * (step S120). This setting is performed by setting the target rotational speed Ne * and the target torque Te * based on the operation line for efficiently operating the engine 22 and the required power Pe *. FIG. 6 shows an example of the operation line of the engine 22 and how the target rotational speed Ne * and the target torque Te * are set. As shown in the figure, the target rotational speed Ne * and the target torque Te * can be obtained from the intersection of the operation line and a curve with a constant required power Pe * (Ne * × Te *).

  When the target rotational speed Ne * and the target torque Te * are set, the set target rotational speed Ne *, the rotational speed Nr (= Nm2 / Gr) of the ring gear shaft 32a, and the gear ratio ρ of the power distribution and integration mechanism 30 are used. The target rotational speed Nm1 * of the motor MG1 is calculated by the following formula (2), and the torque command Tm1 * of the motor MG1 is calculated by the formula (3) based on the calculated target rotational speed Nm1 * and the current rotational speed Nm1. (Step S220). Here, Expression (2) is a dynamic relational expression for the rotating element of the power distribution and integration mechanism 30. FIG. 7 is a collinear diagram showing a dynamic relationship between the number of rotations and torque in the rotating elements of the power distribution and integration mechanism 30. In the figure, the left S-axis indicates the rotation speed of the sun gear 31 that is the rotation speed Nm1 of the motor MG1, the C-axis indicates the rotation speed of the carrier 34 that is the rotation speed Ne of the engine 22, and the R-axis indicates the ring gear 32 (ring gear). The rotational speed Nr of the shaft 32a) is shown. The target rotational speed Nm1 * of the motor MG1 can be easily derived by using the rotational speed relationship in this alignment chart. Therefore, the engine 22 can be rotated at the target rotational speed Ne * by setting the torque command Tm1 * so that the motor MG1 rotates at the target rotational speed Nm1 * and drivingly controlling the motor MG1. Expression (3) is a relational expression in the feedback control for rotating the motor MG1 at the target rotational speed Nm1 *. In Expression (3), “k1” in the second term on the right side is the gain of the proportional term, and the right side The third term “k2” is the gain of the integral term. In FIG. 7, two bold arrows pointing upward on the R axis indicate that torque Te * output from the engine 22 is directly transmitted to the ring gear shaft 32a and torque Tm2 * output from the motor MG2 is a reduction gear. And the torque acting on the ring gear shaft 32a via 35.

Nm1 * ＝ Ne * ・ (1 + ρ) / ρ−Nm2 / (Gr ・ ρ)… (2)
Tm1 * = previous Tm1 * + k1 (Nm1 * −Nm1) + k2∫ (Nm1 * −Nm1) dt (3)

  Next, the internal resistance R of the battery 50 is set based on the battery temperature Tb of the battery 50 input in step S100 (step S140), and the target lower limit voltage Vbmin is set based on the set internal resistance R (step S150). ). In the embodiment, in the embodiment, the relationship between the battery temperature Tb and the internal resistance R is determined in advance and stored in the ROM 74 as an internal resistance setting map. When the battery temperature Tb is given, the internal resistance corresponding to the internal resistance R is stored. The resistance R was derived and set. An example of the internal resistance setting map is shown in FIG. As shown in the figure, the internal resistance R is set so as to increase as the battery temperature Tb decreases. The target lower limit voltage Vbmin is used to determine whether or not there is a possibility of overdischarge of the battery 50. In the embodiment, the relationship between the internal resistance R and the target lower limit voltage Vbmin is determined in advance. A voltage setting map is stored in the ROM 74, and when the internal resistance R is given, the corresponding target lower limit voltage Vbmin is derived and set from the stored map. An example of the target lower limit voltage setting map is shown in FIG. As shown in the figure, the target lower limit voltage Vbmin is set so as to increase as the internal resistance R increases. The reason for this will be described later.

  When the target lower limit voltage Vbmin is set in this way, the terminal voltage Vb of the battery 50 is compared with the target lower limit voltage Vbmin (step S160). When the terminal voltage Vb is equal to or higher than the target lower limit voltage Vbmin, there is a risk of overdischarge of the battery 50. The output limit correction value ΔWout is set to 0 (step S170), and the output limit correction value ΔWout is subtracted from the output limit Wout of the battery 50 to obtain an upper limit of power that can be output from the battery 50. The output allowable limit Woutf is calculated (step S190). Subsequently, a deviation between the power consumption (generated power) of the motor MG1 obtained by multiplying the output allowable limit Woutf and the torque command Tm1 * of the motor MG1 by the current rotational speed Nm1 of the motor MG1 is divided by the rotational speed Nm2 of the motor MG2. Thus, the torque limit Tmax as the upper limit of the torque that may be output from the motor MG2 is calculated by the following equation (4) (step S200), the required torque Tr *, the torque command Tm1 *, the power distribution integration mechanism 30 Using the gear ratio ρ and the gear ratio Gr of the reduction gear 35, a temporary motor torque Tm2tmp as a torque to be output from the motor MG2 is calculated by the equation (5) (step S210), and the calculated temporary motor torque Tm2tmp is torque limited. The torque command Tm2 * of the motor MG2 is set by limiting with Tmax (step S220). Thus, by setting the torque command Tm2 * of the motor MG2, the required torque Tr * output to the ring gear shaft 32a as the drive shaft can be set as a torque limited within the range of the output allowable limit Woutf. Equation (5) can be easily derived from the collinear diagram of FIG. 7 described above.

Tmax = (Woutf-Tm1 * ・ Nm1) / Nm2 (4)
Tm2tmp = (Tr * + Tm1 * / ρ) / Gr (5)

  When the target rotational speed Ne * of the engine 22 and the target torque Te * and the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are set in this way, the target rotational speed Ne * and the target torque Te * of the engine 22 are transmitted to the engine ECU 24. The torque commands Tm1 * and Tm2 * for the motors MG1 and MG2 are transmitted to the motor ECU 40 (step S230), and the drive control routine is terminated. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * performs fuel injection control in the engine 22 such that the engine 22 is operated at an operating point indicated by the target rotational speed Ne * and the target torque Te *. Controls such as ignition control. The motor ECU 40 that has received the torque commands Tm1 * and Tm2 * controls the switching elements of the inverters 41 and 42 so that the motor MG1 is driven by the torque command Tm1 * and the motor MG2 is driven by the torque command Tm2 *. To do.

  On the other hand, when the terminal voltage Vb of the battery 50 is lower than the target lower limit voltage Vbmin in step S160, the output limit correction value ΔWout is calculated by the following equation (6) based on the deviation between the terminal voltage Vb and the target lower limit voltage Vbmin. At the same time (step S180), an output allowable limit Woutf is calculated by subtracting the calculated output limit correction value ΔWout from the output limit Wout (step S190), and output from the motor MG2 using the torque limit Tmax based on the output allowable limit Woutf. The torque command Tm2 * of the motor MG2 is set by limiting the temporary motor torque Tm2tmp as the torque to be executed (steps 200 to S220), the target rotational speed Ne * of the engine 22, the target torque Te *, and the torques of the motors MG1 and MG2 Each of commands Tm1 * and Tm2 * It transmits to ECU (step S230), and a drive control routine is complete | finished. Here, the equation (6) is a feedback control equation for canceling the deviation between the terminal voltage Vb and the target lower limit voltage Vbmin, and the function PID is constituted by a proportional term, an integral term or a differential term in the feedback control. Yes. When the voltage Vb between the terminals of the battery 50 is lower than the target lower limit voltage Vbmin, the torque command Tm2 * of the motor MG2 is set in this way, so that the motor MG2 can be controlled based on the deviation between the terminal voltage Vb and the target lower limit voltage Vbmin. Since the output torque is limited, the power consumption of the motor MG2 is limited, and the battery 50 is charged by supplying surplus power due to this limitation to the battery 50. Here, if a predetermined value is set regardless of the internal resistance R as the target lower limit voltage Vbmin as a threshold for determining whether or not there is a possibility of overdischarge, the battery temperature Tb of the battery 50 is relatively low. When the internal resistance R is relatively large, the battery 50 may be overdischarged because the voltage drop of the battery 50 when the battery 50 discharges is large. On the other hand, as described above, if the target lower limit voltage Vbmin is set so as to increase as the internal resistance R increases, the torque output from the motor MG2 using the target lower limit voltage Vbmin corresponding to the internal resistance R is increased. Since it can restrict | limit, the overdischarge of the battery 50 can be suppressed more.

  ΔWout = PID (Vb, Vbmin)… (6)

  FIG. 10 is an explanatory diagram showing how the terminal voltage Vb of the battery 50 changes with time when the internal resistance R of the battery 50 is relatively large, such as when the battery temperature Tb of the battery 50 is relatively low. In the figure, the voltage Vb1 is a target lower limit voltage Vbmin set when the internal resistance R is relatively small, and the voltage Vb2 is a target lower limit voltage Vbmin set when the internal resistance R is relatively large. Further, in the figure, the solid line shows the time change when the voltage Vb2 is set to the target lower limit voltage Vbmin according to the internal resistance R, and the dotted line is the voltage Vb1 set to the target lower limit voltage Vbmin regardless of the internal resistance R. It is a state of time change. When the voltage Vb1 is set to the target lower limit voltage Vbmin even though the internal resistance R is relatively large, the output limit correction value ΔWout is maintained until the inter-terminal voltage Vb becomes lower than the voltage Vb1 lower than the voltage Vb2, as shown by the dotted line. Is set to a value of 0, and the torque output from the motor MG2 cannot be sufficiently limited. Therefore, the power consumption of the motor MG2 is not sufficiently limited, and the battery 50 may be overdischarged. On the other hand, if the voltage Vb2 is set to the target lower limit voltage Vbmin according to the internal resistance R, as shown by the solid line, the terminal voltage Vb and the target lower limit voltage Vbmin (=) when the terminal voltage Vb becomes lower than the voltage Vb2. Since the torque output from the motor MG2 can be sufficiently limited based on the deviation from Vb2), the power consumption of the motor MG2 can be sufficiently limited, and surplus power due to this limitation is supplied to the battery 50. By charging the battery 50, overdischarge of the battery 50 can be suppressed. When the inter-terminal voltage Vb of the battery 50 becomes equal to or higher than the target lower limit voltage Vbmin, a value 0 is set as the output limit correction value ΔWout.

  According to the hybrid vehicle 20 of the embodiment described above, when the inter-terminal voltage Vb of the battery 50 is lower than the target lower limit voltage Vbmin set to increase as the internal resistance R increases, the inter-terminal voltage Vb and the target lower limit voltage are reduced. Based on the deviation from Vbmin, an output limit correction value ΔWout is calculated by a feedback control equation, and the range of the torque limit Tmax based on the output allowable limit Woutf calculated using this output limit correction value ΔWout and the output limit Wout of the battery 50 Since the torque command Tm2 * of the motor MG2 is set in the motor, the torque output from the motor MG2 is limited based on the target lower limit voltage Vbmin set according to the internal resistance R and the terminal voltage Vb of the battery 50. Can do. As a result, overdischarge of the battery 50 can be further suppressed according to the internal resistance R.

  In the hybrid vehicle 20 of the embodiment, the internal resistance R of the battery 50 is set based on the battery temperature Tb of the battery 50. However, in addition to or instead of the battery temperature Tb, the travel distance of the vehicle from the odometer 89 The internal resistance R of the battery 50 may be set based on L or the time th after the battery 50 is installed in the vehicle.

  In the hybrid vehicle 20 of the embodiment, the target lower limit voltage Vbmin is set so as to increase linearly as the internal resistance R of the battery 50 increases as shown in the target lower limit voltage setting map of FIG. The target lower limit voltage Vbmin may be set so as to increase in a curvilinear or stepwise manner as the internal resistance R increases.

  In the hybrid vehicle 20 of the embodiment, the output limit correction value ΔWout is calculated by the relational expression of the feedback control by the PID control based on the voltage Vb between the terminals of the battery 50 and the target lower limit voltage Vbmin in step S180 of the drive control routine of FIG. However, the feedback control is not limited to PID control. For example, feedback control by PI control without a differential term may be used, and feedback control by proportional control without an integral term may be used.

  In the hybrid vehicle 20 of the embodiment, when the terminal voltage Vb of the battery 50 is lower than the target lower limit voltage Vbmin, the output limit correction value ΔWout is calculated so that the deviation between the terminal voltage Vb and the target lower limit voltage Vbmin is canceled. However, the present invention is not limited to this, and it is only necessary to calculate the output limit correction value ΔWout so that the inter-terminal voltage Vb is equal to or higher than the target lower limit voltage Vbmin.

  In the hybrid vehicle 20 of the embodiment, the control is performed in consideration of whether or not the terminal voltage Vb of the battery 50 is lower than the target lower limit voltage Vbmin in the drive control routine of FIG. Control may be performed in consideration of whether or not the terminal voltage Vb is higher than the target upper limit voltage Vbmax. A drive control routine in this case is shown in FIG. This drive control routine is the same as the drive control routine of FIG. 2 except that the processes of steps S150b to S200b are executed instead of the processes of steps S150 to S200 of the drive control routine of FIG. In this drive control routine, the target upper and lower limit voltages Vbmax and Vbmin are set based on the internal resistance R set in step S140 (step S150b). The target upper and lower limit voltages Vbmax and Vbmin are used to determine whether or not there is a risk of overcharging and overdischarging of the battery 50. In the modification, the relationship between the internal resistance R and the target upper and lower limit voltages Vbmax and Vbmin. Are previously stored as a target upper / lower limit voltage setting map, and when the internal resistance R is given, the corresponding target upper / lower limit voltages Vbmax, Vbmin are derived from the map and set. An example of the target upper / lower limit voltage setting map is shown in FIG. As shown in the figure, the target upper limit voltage Vbmax is set to tend to decrease as the internal resistance R increases, and the target lower limit voltage Vbmin is set to increase as the internal resistance R increases. This is because the former is to suppress overvoltage due to the fact that the larger the internal resistance R is, the more difficult it is to charge, and the latter is to suppress overdischarge due to the fact that the voltage drop becomes large and the discharge becomes easy. Subsequently, the inter-terminal voltage Vb of the battery 50 is compared with the target lower limit voltage Vbmin (step S160b), and the inter-terminal voltage Vb is compared with the target upper limit voltage Vbmax (step S165b). When the inter-terminal voltage Vb is equal to or higher than the target lower limit voltage Vbmin and equal to or lower than the target upper limit voltage Vbmax, it is determined that there is no possibility of overcharge and overdischarge, and a value 0 is set for both the input / output limit correction values ΔWin and ΔWout. (Step S170b) The input / output allowable limits Winf, Woutf are calculated by subtracting the input / output limit correction values ΔWin, ΔWout set from the input / output limits Win, Wout of the battery 50 (step S190b), and the calculated input / output allowable limit is calculated. Torque limits Tmin and Tmax are calculated by using Formula (7) and Formula (4) described above using Winf and Woutf and the power consumption (generated power) of motor MG1 (Step S200b), and the processing after Step S210 is executed. . On the other hand, when the inter-terminal voltage Vb is lower than the target lower limit voltage Vbmin in step S160, it is determined that there is a possibility of overdischarge, the value 0 is set to the input limit correction value ΔWin, and the output limit correction is performed by the above equation (6). A value ΔWout is set (step S180b). When the inter-terminal voltage Vb is larger than the target upper limit voltage Vbmax in step S165b, it is determined that there is a possibility of overcharging, and an input is made based on the inter-terminal voltage Vb and the target upper limit voltage Vbmax. The limit correction value ΔWin is calculated by the following equation (8), the value 0 is set to the output limit correction value ΔWout (step S185b), and the processing after step S190b is executed. Here, Expression (8) is an expression for feedback control for setting the inter-terminal voltage Vb to the target upper limit voltage Vbmax, and the function PID is constituted by a proportional term, an integral term, and a derivative term in the feedback control. Thus, the input / output allowable limit Winf, Woutf is set using the target upper / lower limit voltages Vbmax, Vbmin set based on the inter-terminal voltage Vb of the battery 50 and the internal resistance R, and the input / output allowable limit Winf, By setting torque command Tm2 * of motor MG2 using Woutf, overcharge and overdischarge of battery 50 can be suppressed even when internal resistance R is relatively large.

Tmin = (Winf-Tm1 * ・ Nm1) / Nm2 (7)
ΔWin = PID (Vb, Vbmax)… (8)

  In the hybrid vehicle 20 of the embodiment, the power of the motor MG2 is output to the ring gear shaft 32a as a drive shaft. However, as illustrated in the hybrid vehicle 120 of the modification of FIG. 13, the power of the motor MG2 is output to the ring gear shaft. It may be connected to an axle (an axle connected to wheels 39c and 39d in FIG. 13) different from an axle to which 32a is connected (an axle to which drive wheels 39a and 39b are connected).

  In the hybrid vehicle 20 of the embodiment, the power of the engine 22 is output to the ring gear shaft 32a as the drive shaft connected to the drive wheels 39a and 39b via the power distribution and integration mechanism 30, but the modified example of FIG. The hybrid vehicle 220 includes an inner rotor 232 connected to the crankshaft 26 of the engine 22 and an outer rotor 234 connected to a drive shaft that outputs power to the drive wheels 39a and 39b. A counter-rotor motor 230 that transmits a part of the power to the drive shaft and converts the remaining power into electric power may be provided.

  In the embodiment, the parallel hybrid vehicle 20 that can run using the power from the engine 22 and the power from the motor MG2 has been described. However, the engine, the generator that can generate power using the power from the engine, and the axle are described. The present invention may be applied to a series-type hybrid vehicle including an electric motor that can output power to a drive shaft connected to the generator, and a generator and a battery that can exchange electric power with the electric motor.

  The best mode for carrying out the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Of course, it can be implemented in the form.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 equipped with a power output apparatus as an embodiment of the present invention. 4 is a flowchart showing an example of a drive control routine executed by a hybrid electronic control unit 70. It is explanatory drawing which shows an example of the relationship between battery temperature Tb and input-output restrictions Win and Wout. It is explanatory drawing which shows an example of the relationship between the remaining capacity (SOC) of the battery 50, and the correction coefficient of input / output restrictions Win and Wout. It is explanatory drawing which shows an example of the map for request | requirement torque setting. It is explanatory drawing which shows a mode that an example of the operating line of the engine 22, and target rotational speed Ne * and target torque Te * are set. FIG. 4 is an explanatory diagram showing an example of a collinear diagram for dynamically explaining rotational elements of a power distribution and integration mechanism 30. It is explanatory drawing which shows an example of the map for internal resistance setting. It is explanatory drawing which shows an example of the map for target lower limit voltage setting. FIG. 6 is an explanatory diagram showing how a voltage Vb between terminals of a battery 50 changes with time. It is a flowchart which shows an example of the drive control routine performed by the hybrid electronic control unit 70 of the modification. It is explanatory drawing which shows an example of the map for a target upper / lower limit voltage setting. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 120 according to a modification. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 220 of a modified example.

Explanation of symbols

  20, 120, 220 Hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 28 damper, 30 power distribution integration mechanism, 31 sun gear, 31a sun gear shaft, 32 ring gear, 32a ring gear shaft, 33 Pinion gear, 34 carrier, 35 reduction gear, 37 gear mechanism, 38 differential gear, 39a, 39b, 39c, 39d drive wheel, 40 electronic control unit for motor (motor ECU), 41, 42 inverter, 43, 44 rotational position detection sensor , 48 Rotating shaft, 50 Battery, 52 Battery electronic control unit (battery ECU), 54 Power line, 70 Hybrid electronic control unit, 72 CPU, 74 ROM, 76 RAM, 80 Ignition Switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor, 89 odometer, 230 rotor motor, 232 inner rotor 234 Outer rotor, MG1, MG2 motor.

Claims (13)

A power output device that outputs power to a drive shaft,
An internal combustion engine;
Power generation means capable of generating power using power from the internal combustion engine;
An electric motor capable of inputting and outputting power to the drive shaft;
Power storage means capable of exchanging electric power with the power generation means and the electric motor,
Required driving force setting means for setting required driving force to be output to the driving shaft;
Voltage detection means for detecting the voltage of the power storage means;
Internal resistance estimating means for estimating the internal resistance of the power storage means;
Target lower limit voltage setting means for setting a target lower limit voltage based on the estimated internal resistance of the power storage means;
When the driving force based on the set required driving force is output to the drive shaft and the detected voltage of the power storage means is lower than the set target lower limit voltage, the voltage of the power storage means is equal to or higher than the target lower limit voltage. Control means for controlling the internal combustion engine, the power generation means and the electric motor to be
A power output device comprising:   2. The power output apparatus according to claim 1, wherein the target lower limit voltage setting means is a means for setting the target lower limit voltage such that the target lower limit voltage tends to increase as the estimated internal resistance of the power storage means increases.   When the detected voltage of the power storage means is lower than the set target lower limit voltage, the control means controls the deviation to be canceled based on a deviation between the voltage of the power storage means and the target lower limit voltage. The power output apparatus according to claim 1, wherein the power output apparatus is a means for performing the operation. The power output device according to any one of claims 1 to 3,
Temperature detecting means for detecting the temperature of the power storage means,
The internal resistance estimating means is means for estimating an internal resistance of the power storage means based on the detected temperature of the power storage means.   5. The power output apparatus according to claim 4, wherein the internal resistance estimating means is means for estimating the internal resistance of the power storage means so as to increase as the detected temperature of the power storage means decreases.   The control means sets the output limit of the power storage means as an output allowable limit that allows output from the power storage means when the detected voltage of the power storage means is equal to or higher than the set target lower limit voltage, and the detection When the voltage of the stored power storage means is lower than the set target lower limit voltage, a correction value is set based on the voltage of the power storage means and the target lower limit voltage, and the output limit of the power storage means and the set correction value are The output allowable limit is set on the basis of the set driving force and the motor drive command is set based on the set required driving force and the set output allowable limit, and the motor is driven based on the set drive command. The power output apparatus according to any one of claims 1 to 5, wherein the power output apparatus is a means for controlling the power output. The power output device according to any one of claims 1 to 6,
A target upper limit voltage setting means for setting the target upper limit voltage in a tendency to decrease as the internal resistance of the power storage means increases;
The control means is means for controlling the voltage of the power storage means to be equal to or lower than the target upper limit voltage when the detected voltage of the power storage means is higher than the set target upper limit voltage.   The power generation means is connected to the output shaft of the internal combustion engine and the drive shaft, and outputs power and power input / output for outputting at least part of the power from the internal combustion engine to the drive shaft with input and output of power and power. The power output apparatus according to any one of claims 1 to 7, which is a means.   The power power input / output means has three shafts, that is, an output shaft of the internal combustion engine, the drive shaft, and a rotation shaft, and the remaining shaft is based on power input / output to / from any two of the three shafts. 9. The power output apparatus according to claim 8, comprising a three-axis power input / output means for inputting / outputting power and a generator capable of inputting / outputting power to / from the rotating shaft.   The power drive input / output means has a first rotor connected to the output shaft of the internal combustion engine and a second rotor connected to the drive shaft, and the first rotor and the first rotor The power output apparatus according to claim 8, wherein the power output apparatus is a counter-rotor electric motor that relatively rotates with the two rotors.   An automobile comprising the power output device according to claim 1 and an axle connected to the drive shaft. The automobile according to claim 11,
The internal resistance estimation means is means for estimating the internal resistance of the power storage means based on at least one of the temperature of the power storage means, the travel distance of the vehicle, and the time since the power storage means was installed in the vehicle. Is a car. An internal combustion engine, power generation means capable of generating power using power from the internal combustion engine, an electric motor capable of inputting / outputting power to / from the drive shaft, power storage means capable of exchanging electric power with the power generation means and the motor, A method for controlling a power output device comprising:
(A) setting a required driving force to be output to the driving shaft;
(B) detecting the voltage of the power storage means;
(C) estimating an internal resistance of the power storage means;
(D) setting a target lower limit voltage based on the estimated internal resistance of the power storage means;
(E) When a driving force based on the set required driving force is output to the drive shaft and the detected voltage of the power storage means is lower than the set target lower limit voltage, the voltage of the power storage means is set to the target A method for controlling a power output apparatus, wherein the internal combustion engine, the power generation means, and the electric motor are controlled to be equal to or higher than a lower limit voltage.

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