JP2007126017A - Vehicle drive control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle drive control unit enabling stable motor torque control by the combination of a dynamo and an alternating current motor. <P>SOLUTION: A torque command value Tt of a motor 4 is calculated based on a required driving force of a sub-driving wheel, and a dynamo 7 is controlled at an operating point capable of efficiently generating the torque command value Tt. Further, a torque command value Tm is calculated by adding a time delay to the torque command value Tt, and based on the torque command value Tm, a motor 4 is controlled. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle drive control device that drives a generator with a heat engine (for example, an engine that is an internal combustion engine) that drives a main drive shaft, and drives an AC motor with the output of the generator.

As a conventional vehicle drive control device, there is known a device in which a driven shaft is driven by a direct current motor driven by electric power of a generator and a drive torque is controlled by controlling a field current of the direct current motor. (For example, refer to Patent Document 1).
JP 2001-239852 A

  However, in the above conventional vehicle drive control device, since the motor torque is controlled by applying a DC motor, it is necessary to increase the armature current of the DC motor in order to increase the torque. Since there is a limit in the life of brushes of DC motors, there is a limit in the increase in armature current, and there is an unresolved problem that it is difficult to apply to heavy vehicles or that 4WD performance cannot be improved. .

  By the way, it is conceivable to control the motor torque by applying an AC motor + inverter configuration instead of a DC motor. However, it is generally known that the control response of the generator is low and the motor control response by the inverter is high. When such a generator and an inverter are combined, the output voltage and output current of the generator may fluctuate depending on the control state of the inverter serving as an electric load. Need to work.

For example, in the process where the torque command rapidly increases, the increase in the generator output is delayed, and the motor control moves so as to output the torque command when the inverter input is insufficient, which is disadvantageous in terms of the total vehicle driving force. There is an unresolved problem that an unexpected problem occurs such that the control system diverges.
Therefore, the present invention has been made paying attention to the unsolved problems of the above-described conventional example, and a vehicle drive control device capable of performing stable motor torque control by a combination of a generator and an AC motor. It is intended to provide.

  In order to achieve the above object, a vehicle drive control apparatus according to the present invention calculates a required torque command value of an AC motor based on a required driving force of a driven wheel by a required torque command value calculation means, and requires a motor. The power calculation means calculates the required motor power required by the AC motor based on the required torque command value, the generator control means controls the generator based on the motor required power, and the delay means The target torque command value is calculated by giving a time delay to the required torque command value, and the AC motor is controlled by the motor control unit based on the target torque command value calculated by the delay unit.

  According to the present invention, the target torque command value is calculated by giving a time delay to the required torque command value of the AC motor, and the AC motor is controlled based on the target torque command value. Can be prevented from becoming abnormally small and stable motor torque control can be performed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram when the present invention is applied to a four-wheel drive vehicle.
As shown in FIG. 1, in the vehicle of this embodiment, left and right front wheels 1L and 1R are main drive wheels driven by an engine 2 that is an internal combustion engine, and left and right rear wheels 3L and 3R are driven by a motor 4. Possible driven wheel.

  For example, a main throttle valve and a sub-throttle valve are interposed in the intake pipe line of the engine 2. The throttle opening of the main throttle valve is adjusted and controlled according to the amount of depression of the accelerator pedal. The sub-throttle valve uses a step motor or the like as an actuator, and the opening degree is adjusted and controlled by a rotation angle corresponding to the number of steps. Therefore, by adjusting the throttle opening of the sub-throttle valve to be equal to or less than the opening of the main throttle valve, the engine output torque can be reduced independently of the driver's operation of the accelerator pedal. That is, the adjustment of the opening degree of the sub-throttle valve is the driving force control that suppresses the acceleration slip of the front wheels 1L, 1R by the engine 2.

The output torque Te of the engine 2 is transmitted to the left and right front wheels 1L and 1R through the transmission and the reference gear 5. Further, a part of the output torque Te of the engine 2 is transmitted to the generator 7 via the endless belt 6, so that the generator 7 has a rotation speed Ng obtained by multiplying the rotation speed Ne of the engine 2 by the pulley ratio. Rotate.
The generator 7 becomes a load on the engine 2 in accordance with the field current Ifg adjusted by the 4WD controller 8, and generates power in accordance with the load torque. The magnitude of the power generated by the generator 7 is determined by the magnitude of the rotational speed Ng and the field current Ifg. The rotational speed Ng of the generator 7 can be calculated from the rotational speed Ne of the engine 2 based on the pulley ratio.

  FIG. 2 is a diagram showing the structure of the field current drive circuit of the generator 7. As shown in FIG. 2A, this circuit applies a configuration in which a constant voltage power source such as a 14V battery 7a of a vehicle and an output voltage of the generator itself are selected as a field current power source. Is connected to the field coil 7b to switch the transistor 7c. In this case, when the generator output is lower than the battery voltage Vb, the battery voltage Vb becomes a power source for the field coil 7b in a separate excitation region, the generator output increases, and the output voltage Vg is equal to or higher than the battery voltage Vb. Then, the output voltage Vg of the generator is selected as a self-excited region and becomes a power source for the field coil 7b. That is, since the field current value can be increased by the power supply voltage of the generator, the generator output can be significantly increased.

In the field current drive circuit, only the 14V battery 7a of the vehicle (only the separate excitation region) may be applied as the field current power source as shown in FIG. 2 (b).
The electric power generated by the generator 7 can be supplied to the motor 4 via the junction box 10 and the inverter 9. The drive shaft of the motor 4 can be connected to the rear wheels 3L and 3R via the speed reducer 11 and the clutch 12. In addition, the motor 4 of this embodiment is an AC motor. Moreover, the code | symbol 13 in a figure shows a difference gear.

In the junction box 10, a relay for connecting and disconnecting the inverter 9 and the generator 7 is provided. In a state where this relay is connected, DC power supplied from the generator 7 via a rectifier (not shown) is converted into three-phase AC in the inverter 9 to drive the motor 4.
The junction box 10 is provided with a generator voltage sensor that detects a generated voltage and a generator current sensor that detects a generated current that is an input current of the inverter 9. These detection signals are sent to the 4WD controller 8. Is output. Further, a resolver is connected to the drive shaft of the motor 4 and outputs a magnetic pole position signal θ of the motor 4.

The clutch 12 is a wet multi-plate clutch, for example, and performs fastening and releasing according to a command from the 4WD controller 8. In this embodiment, the clutch as the fastening means is a wet multi-plate clutch. However, for example, a powder clutch or a pump-type clutch may be used.
Each wheel 1L, 1R, 3L, 3R is provided with a wheel speed sensor 27FL, 27FR, 27RL, 27RR. Each wheel speed sensor 27FL, 27FR, 27RL, 27RR outputs a pulse signal corresponding to the rotation speed of the corresponding wheel 1L, 1R, 3L, 3R to the 4WD controller 8 as a wheel speed detection value.

  The 4WD controller 8 includes an arithmetic processing unit such as a microcomputer, for example, and includes wheel speed signals detected by the wheel speed sensors 27FL to 27RR, output signals of voltage sensors and current sensors in the junction box 10, An output signal of a resolver connected to the motor 4 and an accelerator opening corresponding to an amount of depression of an accelerator pedal (not shown) are input.

As shown in FIG. 3, the 4WD controller 8 includes a target motor torque calculation unit 8A as a required torque command value calculation unit, a generator control unit 8B as a generator control unit, a target motor torque determination unit 8C as a delay unit, A motor control unit 8D, a TCS control unit 8E, and a clutch control unit 8F are provided as motor control means.
The target motor torque calculation unit 8A is configured to calculate the required driving force of the rear wheels 3L and 3R as the driven wheels, for example, the wheel speed difference between the front and rear wheels and the accelerator pedal opening signal calculated based on the wheel speed signal of the four wheels. From this, a motor torque command value Tt as a required torque command value of the motor 4 is calculated.

FIG. 4 is a block diagram showing details of the target motor torque calculator 8A. First, the front / rear rotation difference calculation unit 81 calculates the front / rear rotation difference ΔV based on the following equation based on the wheel speed signals Vfr to Vrr of the four wheels.
ΔV = (Vfr + Vfl) / 2− (Vrr−Vrl) / 2 (1)
Then, based on the front-rear rotation difference ΔV, the map stored in advance by the first motor driving force calculation unit 82 is referred to calculate the first motor driving force TΔV and output it to the select high unit described later. The first motor driving force TΔV is set so that the front-rear rotation difference ΔV is increased and proportionally larger.

The vehicle speed calculation unit 83 calculates a vehicle speed signal V by selecting low the wheel speed signal of the four wheels and the total driving force F generated by the vehicle. Here, the total driving force F is obtained by the sum of the front wheel driving force estimated from the torque converter slip ratio and the rear wheel driving force estimated from the motor torque command value Tt.
The second motor driving force calculator 84 calculates the second motor driving force Tv. Specifically, the calculation is performed with reference to a map stored in advance based on the vehicle speed V output from the vehicle speed calculation unit 83 and the accelerator opening degree Acc. The second motor driving force Tv is set so as to increase as the accelerator opening Acc increases and to decrease as the vehicle speed V increases.

Next, in the select high unit 85, the first motor driving force TΔV output from the first motor driving force calculation unit 82 and the second motor driving force Tv output from the second motor driving force calculation unit 84 are obtained. The selected high value is output to the rear wheel TCS control unit 86 as the target torque Ttt.
Then, based on the rear wheel speeds Vrl and Vrr and the vehicle speed V, rear wheel traction control control is performed by a known method, and a torque command value Tt of the motor 4 is output.

The motor control unit 8D performs known vector control shown in FIG. 5 from the torque command value Tt, a torque command value Tm output from another target motor torque determination unit 8C, which will be described later, and the motor rotation speed Vm. Then, the switching control signal of the three-phase power element is output to the inverter 9 to control the three-phase alternating current.
The TCS controller 8E generates an engine generated drive torque demand signal for the ECM by a known method based on the engine generated drive torque demand signal Tet from the engine torque controller (ECM), the front wheel rotational speeds Vfr and Vfl, and the vehicle speed V. Front wheel traction control control is performed by returning Te.

The clutch control unit 8F controls the state of the clutch 12, and controls the clutch 12 to be in a connected state while determining that it is in the four-wheel drive state.
FIG. 6 is a block diagram showing details of the generator control unit 8B that performs power generation control of the generator 7.
The generator control unit 8B includes a motor required power calculation unit 101 as a motor required power calculation unit, a target generated power calculation unit 102, a generated power limit unit 103, a target generated power determination unit 104, and a target operating point setting. Unit 105 and generated power control unit 106, and controls field current Ifg of generator 7.

Based on the torque command value Tt calculated by the target motor torque calculator 8A and the motor rotation speed Vm, the motor required power calculator 101 calculates the power Pm required for the motor 4 based on the following equation.
Pm = Tt × Vm (2)
Based on the required motor power Pm output from the required motor power calculation unit 101, the target generated power calculation unit 102 calculates the required generator power Pg that the generator 7 should output based on the following equation.
Pg = Pm / Иm (3)
Here, Иm is the motor efficiency. That is, the generator required power Pg must be output by the motor efficiency higher than the motor required power Pm.

The generated power limiting unit 103 outputs generated power limit values PL1 and PL2. The power limit value PL1 is an upper limit value for preventing the generated power from exceeding the power determined according to the transmittable torque of the belt that drives the generator 7, and is calculated based on the following equation.
PL1 = Tb × ωg × Иg (4)
Here, Tb is the torque that can be transmitted to the belt, ωg is the rotational speed of the generator 7, Иg is the generator efficiency, and PL1 is the maximum amount of power that the generator 7 can generate when the belt-transmittable torque is Tb. Equivalent to.

That is, the power limit value PL1 is proportionally increased as the rotational speed ωg of the generator 7 increases as shown in FIG.
The power limit value PL2 is an upper limit value for preventing the generated power from exceeding electric power that may cause engine stall or drivability deterioration due to excessive engine load. This limit value PL2 is given from an engine torque controller (ECM).
As shown in FIG. 7B, the power limit value PL2 is calculated to be larger as the rotational speed ωg of the generator 7 is larger and the accelerator opening Acc is larger.

Then, the calculation results of the target generated power calculating unit 102 and the generated power limiting unit 103 are input to the target generated power determining unit 104, the generator required power Pg and the power limit values PL1 and PL2 are selected, and the generator A target output power PG is calculated.
FIG. 7C shows a case where the generator required power Pg is the smallest of the generator required power Pg and the power limit values PL1 and PL2. In this case, the generator required power Pg at the current speed is The target output power PG is selected.
First, the target operating point setting unit 105 calculates a motor torque command value Tt based on the following expression based on the target output power PG output from the target generated power determining unit 104, that is, the motor usable power.
Tt = (PG × Иm) / Vm (5)

  Next, the input voltage and input current of the inverter 9 that can efficiently generate the motor torque command value Tt, that is, the target voltage Vt and the target current It of the generator 7 are determined within the range of the motor usable power PG. Specifically, as shown in FIG. 8, the intersection of the constant power line P corresponding to the motor usable power PG and the maximum efficiency operating dotted line η indicated by the broken line is a target operating point (Vt, It) of the generator 7. Select as

In general, the generator efficiency is high at high voltage and low current, and the motor efficiency does not change much except when it is at a very low current. It is desirable to work. Further, since the system has an upper limit voltage V _max (for example, 60 V) and an upper limit current I _max (determined by the inverter element rating and the generator / motor design. For example, 30 A), the voltage becomes the upper limit voltage V _max . When approaching, an operating point at which the current value increases with a substantially constant or slight increase in voltage is selected, and eventually the current value increases up to the upper limit current I _max . The continuous line of these operating points is the maximum efficiency operating dotted line η, and this maximum efficiency operating dotted line η is stored in advance.

The target voltage Vt thus obtained is input to the generated power control unit 106, and the generated power control unit 106 controls the field current Ifg so that the output voltage V of the generator 7 becomes the target voltage Vt. .
In FIG. 6, the target operating point setting unit 105 corresponds to the target operating point setting unit, and the generated power control unit 106 corresponds to the generator output control unit.

FIG. 9 is a block diagram illustrating the generated power control unit 106 according to the first embodiment. The generated power control unit 106 in the first embodiment sets the generator field current value while monitoring the actual generator field current Ifg so that the deviation between the target voltage Vt and the output voltage V becomes zero. Provide feedback.
First, a deviation ΔV between the output voltage V from the generator voltage sensor and the target voltage Vt is input to the PID control unit 121, and the PID control unit 121 outputs a target field current Ift such that the deviation ΔV becomes zero. .

In the present embodiment, a field current sensor as a field current detection means is provided to detect the actual generator field current Ifg. Then, a deviation ΔIf between the actual field current Ifg detected by the field current sensor and the target field current Ift is obtained and output to the PID control unit 122. The PID control unit 122 controls the real field current Ifg so that the deviation ΔIf becomes zero.
Thereby, the output voltage V of the generator 7 coincides with the target voltage Vt. That is, the current operating point determined from the output voltage V and the output current I of the generator 7 coincides with the target operating point, and the generator 7 is calculated from the power Pm required by the motor 4. The torque command value Tt corresponding to the target output power PG to be output is operated at an operating point where the torque command value Tt can be generated efficiently.

Next, the target motor torque determination unit 8C in FIG. 3 will be described.
In the target motor torque determination unit 8C, a time delay is given to the torque command value Tt calculated based on the equation (5) based on the motor usable power (target output power) PG, so that the target of the motor 4 A torque command value Tm as a torque command value is calculated. That is, the motor 4 is controlled with the torque command value Tm obtained by giving a time delay to the torque command value Tt of the motor 4 calculated based on the required driving force of the rear wheels.

In the present embodiment, the torque command value Tm is calculated by giving the torque command value Tt characteristics of a first-order lag system.
FIG. 10 is a diagram showing the relationship between the torque command value Tt and the torque command value Tm. As shown by the broken line in FIG. 10, when the torque command value Tt is increased from T1 to T2 at time t0, the torque command value Tm is set simultaneously with the increase of the torque command value Tt as shown by the solid line. It gradually rises with a time constant τ and eventually reaches a steady value T2.

In the present embodiment, the time constant τ is set substantially equal to the time constant of the output response of the generator 7.
It is generally known that the control responsiveness of a generator is low (a few seconds in terms of time constant) and the responsiveness of motor control by an inverter is high (several ms to 10 ms). Such a generator and inverter are combined. In the case of the conventional device, for example, the motor control moves so that the output of the generator is delayed while the torque command rapidly increases and the input of the inverter is insufficient. The generator will be used at the operating point with poor electrical efficiency. This will be described with reference to FIG.

  FIG. 11A is a diagram showing an operating point (voltage / current) at the output of the generator 7, that is, the input of the inverter 9. A curve St is a generator output characteristic line (generator output possible characteristic line) with the generator rotation speed and the field current as parameters, and when a field current at a certain rotation speed is given, The machine generates the voltage / current on the output possible characteristic line. A hyperbolic curve P is a constant power line corresponding to a certain torque command value.

  Now, the operating point is at the intersection a0 between the output possible characteristic line St0 and the constant power line P1 corresponding to the torque command value T1, and as shown in FIG. 11B, the torque command value is changed from T1 to T2 at time t0. Increased. In this case, the generator increases the field current toward the operating point where the motor can generate this torque, and increases the generated power. On the other hand, since the motor control by the motor and the inverter has good responsiveness as described above, the operating point is moved so as to output the torque command value quickly on the current output possible characteristic line of the generator.

  That is, when the field current of the generator gradually increases and the output possible characteristic line of the generator becomes St1 at time t1, the operating point is an operation that can output the torque command value T2 on the output possible characteristic line St1. The point moves to the operating point a1, which is the intersection of the output possible characteristic line St1 and the constant power line P2 corresponding to the torque command value T2. Further, when the output possible characteristic line of the generator becomes St2 at time t2, the generator moves to the operating point a2 that is the intersection of the output possible characteristic line St2 and the constant power line P2.

  In this way, the operating point moves to the lower right in the figure, and becomes an operating point of low voltage and large current. Accordingly, as shown by the broken line in FIG. 11B, the actual driving force reaches the torque command value T2 early, but is controlled at an inefficient operating point as shown in FIG. 11C. It will be. Further, when there is a large difference between the state of the generator 7 and the torque command value T2 at time t0, the generator 7 cannot output power corresponding to the torque command value T2 even at time t1. As a result, there is a problem that an unexpected problem occurs such that the control system diverges.

  On the other hand, in the present embodiment, the motor 4 is moved by the torque command value Tm that is time-delayed with respect to the torque command value Tt by the first-order lag system using the time constant τ substantially equal to the output response of the generator 7. This prevents the generator 7 from outputting power corresponding to the torque command value, prevents the control system from diverging, and prevents it from going to the inefficient side.

That is, as shown in FIG. 12A, when the generator operating point is the point a0 on the output possible characteristic line St0, it is assumed that the torque command value T1 is increased to the torque command value T2 at time t0. In this case, the generator control unit 8B performs increase control of the field current Ifg so that the generator operating point becomes the target operating point (Vt, It). If the output possible characteristic line becomes St1 at time t1 and the operating point at that time is the point a1 (V ₁ , I ₁ ) on the output possible characteristic line St1, the target motor torque determination unit 8C uses the torque command value. A torque command value Tm (= T1 ′ <T2) obtained by delaying T2 with a first-order lag system is output, and the motor 4 is controlled with this torque command value Tm.

Since the time constant τ of the first-order lag system is set substantially equal to the time constant of the output response of the generator 7, the constant power line corresponding to the torque command value Tm is substantially equal to the output power of the current generator 7. Become. That is, the constant power line corresponding to the torque command value Tm (= T1 ′) set by the time delay is substantially equal to P1 ′, and the generator operating point at time t1 is the output possible characteristic line St1 and the constant power line. The vicinity of the operating point a1 (V ₁ , I ₁ ) that is the intersection with P1 ′ is maintained.

Thereafter, when the output possible characteristic line becomes St2 at time t2, and the operating point at that time is the target operating point a2 (Vt, It) on the output possible characteristic line St2, the torque command having a steady value (= T2). The motor 4 is controlled by the value Tm.
Therefore, as shown by the broken line in FIG. 12B, the time until the actual driving force reaches the torque command value T2 is longer than that in the conventional apparatus shown in FIG. 11, but as shown in FIG. It can always operate at an efficient operating point.

  As described above, in the first embodiment, the field current of the generator is controlled from the required motor power calculated based on the required torque command value of the motor, and the target that gives a time delay to the required torque command value. By controlling the motor based on the torque command value, the command value to the generator and the command value to the motor are configured differently, so the combination of generator control with low responsiveness and motor control with high responsiveness Even so, it is possible to suppress the control system from diverging or operating with very poor efficiency.

  In addition, a first-order lag system is applied as a method for giving a time delay to the torque command value, and this time constant is set to be approximately equal to the time constant of the output response of the generator, so that the torque command value is set according to the response delay of the generator. The torque command value can be gradually increased so that the inverter / motor control is slowly moved while the generator output is increased. At this time, since the output of the generator itself is controlled with an operating point at which the efficiency is optimal, as a result, operation at an efficient operating point can be maintained.

Furthermore, since the field current of the generator is monitored and feedback control is performed so that the actual field current follows the target field current, the output voltage can surely follow the target voltage.
In the first embodiment, the case where the generated power control unit 106 follows the target field current Ift while monitoring the actual field current Ifg of the generator 7 has been described. However, the present invention is not limited to this. Instead, as shown in FIG. 13, the generator field current may be subjected to PWM control so that the deviation between the target voltage Vt and the output voltage V becomes zero. In this case, first, the deviation ΔV between the target voltage Vt and the output voltage V is output to the PID control unit 123.

The PID control unit 123 controls the PWM duty ratio D of the field current drive circuit of the generator 7 according to the deviation ΔV. Specifically, the PWM duty ratio D is increased when Vt> V, and the PWM duty ratio D is decreased when Vt <V.
For example, the following PID control is performed.
D = α × (Vt−V) + β × ∫ (Vt−V) (7)

FIG. 14 is a characteristic diagram showing the relationship between the PWM duty ratio D and the field current Ifg. The horizontal axis represents the PWM duty ratio D, and the vertical axis represents the field current Ifg. As shown in this characteristic diagram, the field current Ifg does not flow when the duty ratio D is 0%, and a lot of the field current Ifg flows as the duty ratio D approaches 100%.
This characteristic is such that the greater the field power supply voltage Vf, the greater the slope, and the smaller the field coil resistance, the greater the slope. If the generator output voltage Vg is less than or equal to the battery voltage Vb, Ifg = A × D, and when Vg> Vb, Ifg = a × Vf × D. Here, a is a constant.

By controlling the PWM duty ratio D thus output by the PWM drive unit 124, the field current Ifg can be controlled, and as a result, the output voltage V of the generator 7 becomes the target voltage Vt. Can be controlled.
As a result, it is possible to control in a loop with a large output voltage and target voltage, including all error factors of field current control due to variations in field current voltage and field coil resistance value. There is no need to provide a sensor, and the cost can be reduced.
In the process of FIG. 13, the processes of the PID control unit 123 and the PWM drive unit 124 correspond to the duty ratio control means.

As shown in FIG. 15, the generated power control unit 106 may perform feedback control of the multiplication value of the field power supply voltage Vf and the PWM duty ratio D. In this case, the deviation ΔV between the output voltage V and the target voltage Vt is input to the PID control unit 125, and PID control shown in the following equation (8) is performed to output the PWM duty ratio D.
Vf × D = α × (Vt−V) + β × ∫ (Vt−V)
D = {α × (Vt−V) + β × ∫ (Vt−V)} / Vf (8)

  As described above, when Vg> Vb, the field current Ifg = a × Vf × D. From this relationship, it is possible to perform feedback control assuming that (Vf × D) is the field current Ifg. That is, by performing feedback control of the product of the field power supply voltage Vf and the PWM duty ratio D, it is possible to obtain a control effect such that the field current Ifg is substantially feedback controlled. In the region where the field power supply voltage Vf is large, the weight of the PWM duty ratio can be set smaller than that at the time of low voltage, so that appropriate control in consideration of the magnitude of the field power supply voltage can be performed. .

Next, a second embodiment of the present invention will be described.
In the second embodiment, in the target motor torque determination unit 8C of the first embodiment described above, a time change rate is limited so that the torque command value is delayed in time.
In the target motor torque determination unit 8C, a time change rate limit is provided for the torque command value Tt calculated based on the equation (5) based on the motor usable power (target output power) PG. Then, the torque command value Tm of the motor 4 is calculated.

FIG. 16 is a diagram illustrating a relationship between the torque command value Tt and the torque command value Tm. As shown by the broken line in FIG. 16, when the torque command value Tt is increased from T1 to T2 at time t0, the torque command value Tm has a predetermined slope at the same time as the increase of the torque command value Tt, as shown by the solid line. To T2.
In the present embodiment, this slope (change rate limit value) is set to be approximately equal to the actual output increase due to the response delay of the generator 7.

Thus, as in the first embodiment described above, the generator operating point moves along the maximum efficiency operating dotted line η from the operating point a0 to the operating point a2 as shown in FIG. In other words, the operation at the efficient operating point can always be maintained.
As described above, in the second embodiment, the time change rate limit is applied as a method for giving a time delay to the torque command value, and this limit value is set to be approximately equal to the response delay of the generator. The torque command value can be gradually increased in accordance with the actual output increase, and motor control can be performed at an efficient operating point, as in the first embodiment described above.

  In the first and second embodiments, the case where the time constant of the first-order lag system and the limit value of the change rate are set to be approximately equal to the delay amount of the generator response has been described. However, the present invention is not limited to this. In order to prevent the generator operating point from becoming a low-voltage / high-current inefficient area and to prevent the actual torque delay of the motor from becoming excessively large, the delay amount obtained in advance through experiments, etc. May be set.

Next, a third embodiment of the present invention will be described.
In the third embodiment, the torque command value is time-delayed by simulating the response delay of the generator in the target motor torque determination unit 8C of the first embodiment described above.
The target motor torque determination unit 8C predicts a response delay of the generator output, and calculates a torque command value Tm corresponding to an actual output value including the delay with respect to the power generation target value of the generator 7.

First, the response delay of the generator output is accurately predicted from the rotational speed Ng of the generator 7, the field current command value Ifg, etc., and the ratio of the actual output value to the power generation target value of the generator 7 (power generation output value) / (Power generation target value) is calculated.
Then, the torque command value Tt calculated based on the equation (5) based on the motor usable power (target output power) PG is multiplied by the ratio (power generation output value) / (power generation target value). Thus, the torque command value Tm is calculated.
Tm = Tt × (power generation output value) / (power generation target value) (9)

That is, it is shown that the ratio of the power generation output value to the power generation target value is equal to the ratio Tm / Tt of the torque command value Tm to be output at present to the target torque command value Tt. By calculating the command value Tm, the torque command value Tt can be delayed by simulating the response delay of the generator 7.
FIG. 17 is a diagram illustrating a relationship between the torque command value Tt and the torque command value Tm. As shown by the broken line in FIG. 17, when the torque command value Tt is increased from T1 to T2 at time t0, the torque command value Tm gradually increases as T2 increases as shown by the solid line. To rise. Since the delay amount of the torque command value Tm with respect to the torque command value Tt is equal to the delay amount of the power generation output value with respect to the power generation target value, the torque command value Tm also increases in accordance with the actual output increase of the generator 7. .

As a result, the generator operating point always maintains the current operating point. That is, as shown in FIG. 12A, the generator operating point moves from the operating point a0 to the operating point a2 along the maximum efficiency operating dotted line η, so that the operation at the efficient operating point is always performed. Can be maintained.
As described above, in the third embodiment, since a method of simulating a response delay of the generator output is applied as a method of giving a time delay to the torque command value, the torque command is adjusted in accordance with the actual output increase of the generator. The value can be gradually increased, and the motor control can be performed at an efficient operating point as in the first embodiment described above.

  In the first to third embodiments, the delay amount may be changed according to the change in the torque command value Tt. That is, the delay amount may be set larger as the change amount of the torque command value Tt is larger, or the delay amount may be set larger as the change rate of the torque command value Tt is larger. In this case, the torque command value Tm can be calculated so as to more effectively maintain the operation at the efficient operating point according to the change in the torque command value Tt.

Next, a fourth embodiment of the present invention will be described.
In the fourth embodiment, the generator control unit 8B performs feedback control so that the current output possible characteristic line of the generator becomes a target output possible characteristic line.
That is, as shown in FIG. 18 for the generator control unit 8B in the fourth embodiment, the target operating point setting unit 105 shown in FIG. 6 is changed to V of the output possible characteristic line St including the target operating point from the target output power PG. A current operating point detection unit 108 that outputs the V-axis intercept V ₀ of the output possible characteristic line S including the current operating point (V, I) is replaced with the target operating point setting unit 107 that outputs the axis intercept V ₀ t. In addition, the generated power control unit 106 controls the generated power control unit 106 so that the V-axis intercept V ₀ detected by the current operating point detection unit 108 becomes the target V-axis intercept V ₀ t set by the target operating point setting unit 107. Except for the replacement with the unit 109, the same processing as in FIG. 6 is performed, and the same reference numerals are given to the portions performing the same processing as in FIG. 6, and the detailed description thereof is omitted.

  In the target operating point setting unit 107, similarly to the target operating point setting unit 105 described above, first, based on the target output power PG output from the target generated power determining unit 104, that is, the motor usable power, the above equation (5) is obtained. Based on the motor torque command value Tt. Next, as shown in FIG. 8 described above, the intersection of the power constant line P corresponding to the motor usable power PG and the maximum efficiency operating point line η is selected as the target operating point (Vt, It) of the generator 7. .

Then, a target V-axis intercept V ₀ t of the output possible characteristic line St including the target operating point (Vt, It) shown in FIG. 19 is calculated. Specifically, based on the target voltage Vt and the target current It, the target V-axis intercept V ₀ t is calculated based on the linear approximate expression Vt = −a × It + V ₀ t of the output possible characteristic line St.
The current operating point detector 108 calculates the V-axis intercept V ₀ of the output possible characteristic line S including the current operating point (V, I) shown in FIG. Specifically, based on the current voltage V and current I, the V-axis intercept V ₀ is calculated based on the linear approximate expression V = −a × I + V ₀ of the output possible characteristic line S.
The generated power control unit 109 controls the increase / decrease of the field current Ifg of the generator 7 according to the magnitude relationship between the V-axis intercept V ₀ and the target V-axis intercept V ₀ t.

For example, even if the voltage and current change due to fluctuations in the input impedance on the inverter side, the voltage and current move on the output possible characteristic line of the generator, so the V-axis intercept does not change. Therefore, by matching the V-axis intercept V ₀ to the target V-axis intercept V ₀ t, to eliminate the difference between the output possible characteristic line St of the current output possible characteristic line S and target.
By the way, as a method of eliminating the difference between the current output possible characteristic line S and the target output possible characteristic line St, it is possible to compare the relationship between the output possible characteristic line S and St using a non-linear map. In such a region, the output possible characteristic line is monotonously decreased, and therefore, a method using linear approximation is practically sufficient.

FIG. 20 is a block diagram showing details of the generated power control unit 109.
First, the deviation [Delta] V ₀ and V-axis intercept V ₀ which from the target V-axis intercept V ₀ t and the current operating point detecting unit 108 from the target operating point setting part 107 is input to the PID controller 126, PID controller 126 The target field current Ift is output so that the deviation ΔV ₀ becomes zero.
Then, a deviation ΔIf between the actual field current Ifg detected by the field current sensor and the target field current Ift is obtained and output to the PID control unit 127. The PID control unit 127 controls the real field current Ifg so that the deviation ΔIf becomes zero.

As a result, the V-axis intercept V ₀ matches the target V-axis intercept V ₀ t.
Thus, in the fourth embodiment, focusing on the output possible characteristic line of the generator, the difference between the output possible characteristic line including the target operating point and the output possible characteristic line including the current operating point is eliminated. In addition, since the field current of the generator is fed back, stable generator control can be performed.
In addition, since the field current of the generator is controlled so that the V-axis intercept of the current output-possible characteristic line becomes the V-axis intercept of the target output-possible characteristic line, it affects the fluctuation of the input impedance on the inverter side. Stable generator control can be performed without receiving.

In the fourth embodiment, the case where the generated power control unit 109 follows the target field current Ift while monitoring the actual field current Ifg of the generator 7 has been described. However, the present invention is not limited to this. Instead, the generator field current may be PWM controlled as in FIG. 13 described above. In this case, control is performed so that the deviation between the target V-axis intercept V ₀ t and the V-axis intercept V ₀ becomes zero.

Similarly to FIG. 15 described above, the generated power control unit 109 may perform feedback control of the multiplication value of the field power supply voltage Vf and the PWM duty ratio D. In this case, PID control is performed on the deviation between the target V-axis intercept V ₀ t and the V-axis intercept V ₀ .
In each of the above-described embodiments, the target motor torque determining unit 8C calculates the torque command value Tm by giving a first-order lag system characteristic to the torque command value Tt or by providing a time change rate limit. Although the case has been described, the present invention is not limited to this, and the torque command value Tm determination method shown in the first to third embodiments may be applied in combination.

It is a schematic structure figure showing an embodiment of the present invention. It is a figure which shows the structure of a generator. It is a block diagram which shows the detail of 4WD controller of FIG. It is a block diagram which shows the detail of the target motor torque calculating part of FIG. It is a block diagram which shows the detail of the motor control part of FIG. It is a block diagram which shows the detail of the generator control part of FIG. It is a figure which shows the relationship between an electric power limit value and target output electric power. It is a figure explaining the selection method of a target operating point. It is a block diagram which shows the detail of the generated electric power control part in 1st Embodiment. It is a figure which shows the change of the torque command value Tm in 1st Embodiment. It is a figure explaining operation | movement in a conventional apparatus. It is a figure explaining the operation | movement in this invention. It is a block diagram which shows another example of the generated electric power control part in 1st Embodiment. It is a characteristic view which shows the relationship between PWM duty ratio D and field current Ifg. It is a block diagram which shows another example of the generated electric power control part in 1st Embodiment. It is a figure which shows the change of the torque command value Tm in 2nd Embodiment. It is a figure which shows the change of the torque command value Tm in 3rd Embodiment. It is a block diagram which shows the detail of the generator control part of FIG. 3 in 7th Embodiment. It is a figure explaining the outline | summary of the generator control in 7th Embodiment. It is a block diagram which shows the detail of the generated electric power control part in 7th Embodiment.

Explanation of symbols

1L, 1R Front wheel 2 Engine 3L, 3R Rear wheel 4 Motor 6 Belt 7 Generator 8 4WD controller 8A Target motor torque calculation unit 8B Generator control unit 8C Target motor torque determination unit 8D Motor control unit 8E TCS control unit 8F Clutch control unit DESCRIPTION OF SYMBOLS 9 Inverter 10 Junction box 11 Reducer 12 Clutch 27FL, 27FR, 27RL, 27RR Wheel speed sensor 101 Motor required power calculating part 102 Target generated power calculating part 103 Generated power limiting part 104 Target generated power determining part 105 Target operating point setting part 106 Generated power control unit 107 Target operating point setting unit 108 Current operating point detection unit 109 Generated power control unit

Claims (13)

A vehicle drive control device comprising: a heat engine that drives main drive wheels; a generator that is driven by the heat engine; and an AC motor that is supplied with electric power from the generator via an inverter to drive the driven wheels In
Requested torque command value computing means for computing a requested torque command value of the AC motor based on the requested driving force of the driven wheel, and generator control means for controlling the generator based on the requested torque command value; A delay unit that calculates a target torque command value by giving a time delay to the required torque command value; and a motor control unit that controls the AC motor based on the target torque command value calculated by the delay unit. A vehicle drive control device.   2. The vehicle drive control device according to claim 1, wherein the delay means calculates the target torque command value by giving a first-order lag characteristic to the required torque command value.   2. The vehicle drive control device according to claim 1, wherein the delay unit calculates the target torque command value by providing a restriction on a time change rate with respect to the required torque command value.   The said delay means calculates the said target torque command value by simulating the response delay of the said generator with respect to the said request | required torque command value, The any one of Claims 1-3 characterized by the above-mentioned. Vehicle drive control device.   The delay means sets the delay amount of the target torque command value with respect to the required torque command value to be larger as the change amount of the required torque command value is larger. The vehicle drive control device described in 1.   The delay means sets the delay amount of the target torque command value with respect to the required torque command value as the rate of change of the required torque command value is larger. The vehicle drive control device described in 1.   The generator control means includes motor required power calculation means for calculating required motor power required by the AC motor based on the required torque command value, and a target operating point of the generator based on the required motor power. 2. A target operating point setting means for setting, and a generator output control means for controlling a field of the generator based on the target operating point set by the target operating point setting means. The vehicle drive control device according to any one of? 6.   8. The vehicle drive control device according to claim 7, wherein the generator output control means controls a field of the generator so that an output voltage of the generator becomes a voltage of the target operating point. .   The generator output control means is configured such that a current generator output characteristic line including an operating point determined from the output voltage and output current of the generator becomes a target generator output characteristic line including the target operating point. 8. The vehicle drive control device according to claim 7, wherein a field of the generator is controlled.   The generator output characteristic line is a linear line, and the generator output control means is configured so that the intercept of the current generator output characteristic line becomes an intercept of the target generator output characteristic line. The vehicle drive control device according to claim 9, wherein a field is controlled.   Field current detection means for detecting the field current of the generator is provided, and the generator output control means is configured such that an operating point determined from the output voltage and output current of the generator is the target operating point. The vehicle drive control device according to any one of claims 7 to 10, wherein the field current detected by the field current detection means is feedback-controlled.   The generator output control means is a duty control unit configured to control a PWM duty ratio of a field current drive circuit of the generator so that an operating point determined from an output voltage and an output current of the generator becomes the target operating point. The vehicle drive control device according to any one of claims 7 to 10, further comprising a ratio control means.   13. The vehicle drive control device according to claim 12, wherein the duty ratio control means sets the PWM duty ratio in accordance with a power supply voltage of the field current drive circuit.

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