JP2007137359A - Vehicular driving controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular driving controller which performs stable motor torque control by a combination of a power generator and an AC motor. <P>SOLUTION: A target output power PG to be outputted by the power generator 7 is calculated on the basis of a motor needed power Pm needed by the motor 4, and the power generator 7 is controlled at an operation point wherein a torque instruction value Tt calculated on the basis of the target output power PG is efficiently generated. A torque instruction value Tm is calculated on the basis of the operation point present inside the stable operation range (wherein a power generator output voltage does not exceed a fail voltage V<SB>max</SB>) on an outputtable characteristic line St determined from a present output current I and output voltage V of the power generator 7, and the motor 4 is controlled on the basis of the torque instruction value Tm. <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 in which the torque command rapidly decreases, there is an unresolved problem that the decrease in the generator output is delayed, and the component may be damaged when the generator output voltage exceeds a predetermined value (fail voltage).
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, the vehicle drive control device according to the present invention controls the field of the generator based on the required motor power required by the AC motor by the field control means, and sets the output state of the generator. Based on this, the AC motor is controlled by the motor control means so as to operate in a stable operation region where the generator can operate stably.

  According to the present invention, since the AC motor is controlled based on the state of the generator so that the generator operates in the stable operation region, it is possible to prevent the output voltage of the generator from rising abnormally. Thus, it is possible to obtain an effect that it is possible to perform stable motor torque control by preventing breakage of parts.

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 (heat engine), and left and right rear wheels 3L and 3R are This is a driven wheel that can be driven by the motor 4.

  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, a generator control unit 8B as a field control unit, a target motor torque determination unit 8C as a torque command value limiting unit, a motor control unit 8D, and a TCS control. Part 8E and a clutch control part 8F. In FIG. 3, the target motor torque determining unit 8C and the motor control unit 8D constitute a motor control means.

The target motor torque calculation unit 8A calculates a motor torque command value Tt from the wheel speed difference between the front and rear wheels calculated based on the wheel speed signals of the four wheels and the accelerator pedal opening signal.
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 generator control unit 8B controls the field current Ifg of the generator 7 from the torque command value Tt, as will be described later.
The target motor torque determination unit 8C calculates a torque command value Tm of the motor 4 from the output voltage V and output current I of the generator 7 and outputs the torque command value Tm to the motor control unit 8D, as will be described later.
The motor control unit 8D performs known vector control shown in FIG. 5 from the torque command value Tm output from the target motor torque determination unit 8C different from the torque command value Tt 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, a target generated power calculation unit 102, a generated power limit unit 103, a target generated power determination unit 104, a target operating point setting unit 105, and a generated power control. And controls the field current Ifg of the 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)
The processing shown in the above equation (5) corresponds to the torque command value calculation means.

  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.

FIG. 10 is a block diagram showing details of the target motor torque determination unit 8C in FIG.
This target motor torque determination unit 8C calculates the power at the intersection of the output possible characteristic line St of the generator 7 and the boundary line η ₀ of the stable operation region where the generator 7 can operate stably, so-called output possible power Pabl. An outputable motor torque calculation unit 201 that calculates and outputs an outputable motor torque Table ₀ corresponding to the outputable power Pabl is provided.

Here, the output possible characteristic line St is a line indicating the output characteristics of the generator with the rotation speed of the generator and the field current as parameters, and when a field current having a certain rotation speed is given. The generator generates a voltage / current on the output possible characteristic line St. A hyperbolic curve P is a constant power line corresponding to a certain torque command value. The stable boundary line η ₀ is a voltage-current relationship line connecting the maximum output power on the output possible characteristic line St for each field current of the generator 7, and is stored in advance for each engine speed. Keep it.

Further, the target motor torque determining unit 8C includes a select low unit 202 for selecting low the output possible motor torque Tab ₀ and the motor torque command value Tt calculated based on the equation (5), and the generator 7. The power at the intersection of the output possible characteristic line St and the fail voltage V _max (for example, 60 V) as the voltage upper limit value, that is, the so-called minimum output power Pmin is calculated, and the minimum output motor torque Tmin corresponding to the minimum output power Pmin is calculated. A minimum output motor torque calculation unit 203 for output, and a select high unit 204 for selecting high the final output possible motor torque Tabl selected by the select low unit 202 and the minimum output motor torque Tmin are provided.

With such a configuration, the motor torque command value (vehicle required torque) Tt calculated based on the required motor power is calculated on the intersection of the output possible characteristic line St and the stable boundary line η ₀ , that is, on the output possible characteristic line St. The output possible motor torque Tabl corresponding to the operating point at which the output power becomes maximum is the upper limit value, and the minimum output motor torque Tmin corresponding to the operating point at which the voltage value is the fail voltage V _max on the output possible characteristic line St is set as the lower limit value. Will limit.

In other words, the motor for causing the generator 7 to operate at an operating point in the stable operating region on the output possible characteristic line St including the operating point determined from the output voltage V and the output current I of the generator 7. The torque command value Tm of 4 is calculated. At this time, among the operating points on the output possible characteristic line St, an operating point whose voltage value is lower than the fail voltage V _max and whose voltage value is higher than the operating point at which the output power is maximum is within the stable operating region. A point.

FIG. 11 is a flowchart showing a motor torque command value calculation process executed by the target motor torque determination unit 8C. First, various data are read in step S1. Specifically, the output voltage V and output current I of the generator 7, the engine speed Ne, the motor rotation speed Vm, and the motor torque command value Tt calculated by the generator control unit 8B are read.
Next, the process proceeds to step S2, where the field current currently output by the generator 7 is estimated from the output voltage V and output current I of the generator 7 and the engine speed Ne, and an output possible characteristic line St is obtained. calculate.

Next, in step S3, the operating point of the voltage value on the output possible characteristic line St that is calculated at step S2 is the voltage upper limit value, i.e. the voltage at the intersection of the output possible characteristic line St and fail voltage V _max and current , And the minimum output power Pmin is calculated from these detected values, and then the process proceeds to step S4. The minimum output power Pmin calculated in this way is the power that the generator 7 needs to output at a minimum.
In step S4, a minimum output motor torque Tmin corresponding to the minimum output power Pmin is calculated based on the following equation based on the minimum output power Pmin, the motor efficiency Иm, and the motor rotation speed Vm.
Tmin = (Pmin × Иm) / Vm (6)

Next, in step S5, the operating point at which the power value reaches the maximum power value on the output possible characteristic line St, that is, the voltage and current at the intersection of the output possible characteristic line St and the stable boundary line η ₀ are detected. After calculating the output possible power Pabl from the detected value, the process proceeds to step S6.
In step S6, based on the output possible electric power Pabl, the motor efficiency Иm, and the motor rotation speed Vm, the output possible motor torque Tabl ₀ corresponding to the output possible electric power Pabl is calculated based on the following equation.
Table ₀ = (Pabl × Иm) / Vm (7)

Next, the process proceeds to step S7, where the output possible motor torque Tabl ₀ calculated in the step S6 and the motor torque command value Tt calculated based on the equation (5) by the generator control unit 8B are selected low. Then, the final outputtable motor torque Tabl is calculated, and the process proceeds to step S8.
Tabl = min (Table ₀ , Tt) (8)

In step S8, the minimum output motor torque Tmin calculated in step S4 and the final outputtable motor torque Tabl calculated in step S7 are selected high to calculate a motor torque command value Tm.
Tm = max (Tmin, Tabl) (9)
Next, in step S9, the motor torque command value Tm calculated in step S8 is output to the motor control unit 8D, and then the motor torque command value calculation process is terminated.

By the way, it is generally known that the control response of the generator is low and the response of the motor control by the inverter is high. When such a generator and an inverter are combined, in the conventional device, for example, the torque command decreases rapidly. In the process, the decrease in the generator output is delayed, and the generator output voltage may exceed a predetermined value (fail voltage). This will be described with reference to FIG.
FIG. 12A is a diagram showing the operating point (voltage / current) at the output of the generator 7, that is, at the input of the inverter 9.

  Now, the operating point of the generator 7 is at the intersection a0 between the output possible characteristic line St0 and the constant power line P0 corresponding to the torque command value T1, and as shown in FIG. 12 (b), the torque command value is at time t0. Assume that T1 has decreased to T2. In this case, the generator 7 reduces the field current Ifg toward an operating point at which the motor 4 can generate this torque (FIG. 12E), and decreases 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, before the field current Ifg of the generator decreases, the operating point corresponds to the operating point at which the torque command value T2 can be output on the output possible characteristic line St0, that is, the output possible characteristic line St0 and the torque command value T2. It moves to the operating point a1, which is the intersection with the constant power line P1.
In this way, the operating point moves to the upper left in the figure, and becomes an operating point of high voltage and low current. At time t1, the upper limit voltage (fail voltage) V _max of the system is exceeded, and when such a high voltage fail occurs, there is a problem that parts are damaged.

On the other hand, in this embodiment, the output voltage and output current of the generator 7 at each time are monitored, and the motor is moved with a torque command value that does not cause a high voltage failure on the output possible characteristic line of the generator 7 at that time. This prevents problems such as component damage.
As shown in FIG. 13A, when the generator operating point is a point a0 on the output possible characteristic line St0, it is assumed that the torque command value T1 is decreased to the torque command value T2 at time t0. In this case, the generator control unit 8B performs the reduction control of the field current Ifg so that the generator operating point becomes the target operating point (Vt, It) (FIG. 13 (e)).

Also, the target motor torque determining part 8C, the voltage value and current value at the intersection of the output possible characteristic line St0 and fail voltage V _max in step S3 in FIG. 11, the minimum output power Pmin is calculated, the minimum output in step S4 A minimum output motor torque Tmin corresponding to the electric power Pmin is calculated. Since the motor torque command value T2 is smaller between the originally required motor torque command value T2 and the outputtable motor torque Tabl ₀ calculated in step S6, the motor torque command value T2 is finally output in step S7. Set as torque Tabl. Since the minimum output motor torque Tmin and the minimum output motor torque Tabl (= T2) are larger than the minimum output motor torque Tmin, the minimum output power is obtained from the result of the select high shown in the equation (9) in step S8. Pmin is set as a torque command value Tm (= T1 ′> T2), and the motor 4 is controlled by this torque command value Tm. Thus, by providing the torque command value with a limit value in which the upper limit is output possible motor torque Tabl ₀ and the lower limit is minimum output motor torque Tmin, the generator operating point is within the stable operation range on the output possible characteristic line St. This is the operating point a2.

Thereafter, when the field current Ifg of the generator 7 gradually decreases, the output possible characteristic line St also changes, and is calculated from the power value at the intersection of the output possible characteristic line St and the fail voltage V _max in accordance with the response of the generator. The minimum output motor torque Tmin is also reduced. When the minimum output motor torque Tmin becomes smaller than the originally required motor torque command value T2 at time t2, the motor torque command value T2 is set as the torque command value Tm in step S8, and the motor 4 is controlled by this torque command value Tm. Is done.

Therefore, as shown by the solid line in FIG. 13B, the time until the actual driving force reaches the torque command value T2 is longer than that in the conventional apparatus shown in FIG. 12, but as shown in FIG. 13D. It is possible to operate at an operating point that does not always result in a high voltage failure.
Further, when the torque command value is assumed to have jumped to the output enable motor torque Tabl ₀ greater than T3 (not shown) from T1, the output enable motor torque Tabl ₀ as a result of the select low in step S7 is the final possible output motor Set as torque Tabl. Then, the output possible motor torque Tabl is set as the torque command value Tm (<T3) according to the result of the select high shown in the equation (9) in step S8, and the motor 4 is controlled by this torque command value Tm. At this time, the generator operating point is the operating point a3 in the stable operating region on the output possible characteristic line St.

That is, when the torque command value (originally required torque) is in the region from the minimum output motor torque Tmin, which is the lower limit value, to the output possible motor torque Tabl _0, which is the upper limit value, the motor 4 is controlled with the torque command value, when the torque command value is below the minimum output motor torque Tmin is the motor 4 is controlled by the minimum output motor torque Tmin, when the torque command value exceeds the available output motor torque Tabl ₀ is the output enable motor torque Tabl ₀ The motor 4 is controlled.

 As described above, in the first embodiment, the field current of the generator is controlled from the power required by the motor, and the motor is controlled from the output voltage and output current of the current generator. Because the command value for the motor and the command value for the motor are configured differently, the control system diverges or the efficiency is very poor even when the generator control with low response and the motor control with high response are combined. It can suppress operating.

  In addition, since the motor is controlled so that the generator operates in the stable operation region based on the state of the generator, the operating point of the generator is always maintained even when the torque command value of the motor changes rapidly. Therefore, it is possible to prevent the operating point of the generator from falling into an unstable region of low voltage and large current, or from being applied to a high voltage fail region.

  Furthermore, by selecting the minimum output motor torque calculated based on the operating point of the intersection of the current generator output possible characteristic line and the high voltage fail threshold and the originally required motor torque command value, the target is obtained. Since the motor is controlled by setting a lower limit on the motor torque, the output voltage of the generator does not rise abnormally in the process where the torque command value rapidly decreases, and it is possible to reliably prevent problems such as component damage. be able to.

  In addition, the target motor can be selected by selecting low the output possible motor torque calculated based on the operating point of the intersection of the current generator output possible characteristic line and the stable boundary line and the originally required motor torque command value. Since the motor is controlled by setting an upper limit for the torque, it is possible to reliably prevent the generator from being used at an operating point with a low voltage and a large current, which has a poor electrical efficiency, in the process of rapidly increasing the torque command value.

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 above first embodiment has explained the case to set 60V is the upper limit voltage of the fail voltage V _max system, not limited to this, a margin for the upper limit voltage of the system For example, it may be set to about 55V.

  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. 14, the generator field current may be PWM-controlled 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) (10)

FIG. 15 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, when the duty ratio D is 0%, the field current Ifg does not flow, and as the duty ratio D approaches 100%, a lot of the field current Ifg flows.
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. 14, 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. 16, the generated power control unit 106 may feedback control 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 (11) 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 (11)

  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. Further, 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, 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. 17 for the generator control unit 8B in the second 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. 18 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 detection unit 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. 19 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 second 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 second 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. 14 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. 16 described above, the generated power control unit 109 may feedback control 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 .

Next, the operation of the present invention will be described with reference to FIG.
In FIG. 20, (a) is the accelerator opening Acc, (b) is the vehicle speed signal V, (c) is the engine command torque Te, (d) is the torque command value Tt, (e) is the motor required power Pm and power generation. The target output power PG, (f) of the machine 7 is the PWM duty ratio D in the field current control.
When the accelerator opening changes in a decreasing direction as shown in FIG. 20A, the front wheel speeds Vfr and Vfl change as shown by the broken lines in FIG. 20B, and the rear wheel speeds Vrr and Vrl change as shown in FIG. b) changes as indicated by the one-dot chain line, and as a result, the vehicle speed V changes as indicated by the solid line in FIG.

The torque demand signal Tet determined by the ECM from the accelerator opening and the like is as shown by the broken line in FIG. 20C, and the torque demand signal Te modulated by the front wheel traction control control of the TCS control unit 8E is shown in FIG. As shown by the solid line in c).
In FIG. 20D, the thin line represents the first motor driving force TΔV, and the alternate long and short dash line represents the second motor driving force Tv. As shown in the detailed block diagram of the target motor torque calculator 8A in FIG. 6, the signal selected by the select high of the first motor driving force TΔV and the second motor driving force Tv is the target torque Ttt, and the rear wheel speed If the rear wheel TCS control does not operate due to the relationship between Vrr, Vrl and the vehicle speed V, Tt = Ttt, and the direction of abrupt phenomenon changes as shown by the bold line in FIG.

  Then, based on this torque command value Tt, the required motor power Pm is calculated by the required motor power calculation unit 8B, as shown by the broken line in FIG. Further, in the target generated power calculation unit 101 in FIG. 6, the generator required power Pg is calculated based on the motor required power Pm. At this time, assuming that the power limit values PL1 and PL2 output from the generated power limiting unit 102 are larger than the generator required power Pg, the target output power PG = Pg of the generator 7 and the solid line in FIG. As shown.

Based on the signals calculated in this manner, the field control of the generator 7 and the torque control of the motor 4 in each of the embodiments described above are performed, and the results shown in FIGS.
FIG. 20G shows the field current If of the generator 7. As is apparent from this figure, the field current If decreases following the target output power PG indicated by the solid line in FIG. Accordingly, as shown in FIG. 20 (h), the actual output power P of the generator 7 coincides with the target output power PG, and the power to be output by the generator 7 is appropriately output. Become.

At this time, the target motor torque rapidly decreases as shown by the thin line in FIG. 20 (j), but the lower limit is set for the target torque command by the minimum output motor torque calculation unit 203 and the select high unit 204. As a result, the motor torque T actually generated by the motor 4 is as shown by the bold line in FIG. As described above, the actual motor torque T is generated larger than the originally required target torque command Tt, and even if the torque command value suddenly decreases, the generator operating point becomes a high voltage due to the delay in the decrease in the generator output. The failure can be prevented.
As described above, in each of the above embodiments, the DC power supplied from the generator via the rectifier is converted into the three-phase AC by the inverter by the combination of the generator and the AC motor, and stable motor torque control is performed. Can do.

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 block diagram which shows the detail of the target motor torque determination part of FIG. It is a flowchart which shows the motor torque command value calculation process performed in the target motor torque determination part of FIG. 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 block diagram which shows the detail of the generator control part of FIG. 3 in 2nd Embodiment. It is a figure explaining the outline | summary of the generator control in 2nd Embodiment. It is a block diagram which shows the detail of the generated electric power control part in 2nd Embodiment. It is a figure explaining operation | movement of this invention.

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 201 Outputtable motor torque calculation unit 202 Select low unit 203 Minimum output motor torque calculation unit 204 Select high unit

Claims (11)

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
Field control means for controlling the field of the generator based on the required motor power required by the AC motor, and an area where the generator can operate stably based on the output state of the generator A vehicle drive control device comprising: motor control means for controlling the AC motor so as to operate in a certain stable operation region.   Torque command value calculation means for calculating a torque command value of the AC motor based on the required motor power required by the AC motor, the motor control means is configured to calculate the torque based on the output state of the generator. The generator has a torque command value limiting means for limiting the command value, and the generator operates in the stable operation region by controlling the AC motor based on the torque command value limited by the torque command value limiting means. The vehicle drive control device according to claim 1, wherein:   The torque command value limiting means includes the torque command value according to a torque corresponding to an operating point at which the voltage value is a voltage upper limit value on a generator output characteristic line including an operating point determined from the output voltage and output current of the generator. The vehicle drive control device according to claim 2, wherein a lower limit is provided for the value.   The torque command value limiting means sets the torque command value to the torque command value by a torque corresponding to an operating point at which output power is maximum on a generator output characteristic line including an operating point determined from the output voltage and output current of the generator. 4. The vehicle drive control device according to claim 2, wherein an upper limit is provided.   The field control means is based on target operating point setting means for setting a target operating point of the generator based on motor power required by the AC motor, and on the target operating point set by the target operating point setting means. The vehicle drive control device according to any one of claims 1 to 4, further comprising a generator output control means for controlling a field of the generator.   6. The vehicle drive control device according to claim 5, 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. 6. The vehicle drive control device according to claim 5, 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 7, 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 claim 5, wherein the field current detected by the field current detection means is feedback-controlled.   The generator output control means controls the duty ratio for controlling the PWM duty ratio of the field current drive circuit of the generator so that the operating point determined from the output voltage and output current of the generator becomes the target operating point. The vehicle drive control device according to claim 5, further comprising a ratio control unit.   11. The vehicle drive control device according to claim 10, 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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