JP2008199737A - Motor controller, and drive force controller of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress deterioration of motor torque while heat generation of an invertor when a motor is in a locked state is suppressed. <P>SOLUTION: A motor controller conducts supplied power from a power supply source to an armature of the motor 4 through the invertor and controls current flowing to a field coil 4a of the motor 4. When it is decided that a rotor of the motor 4 is in the mechanically restrained locked state, a direction of field current Ifm of the motor 4 is inverted at a prescribed period and an on/off state of switching elements 9a in respective phases of the invertor 9 is switched in synchronizing with inversion of field current Ifm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is applied to a hybrid vehicle or the like, and relates to a motor control device that drives wheels and a vehicle driving force control device including the motor control device.

As a conventional vehicle motor control device, for example, there is a device described in Patent Document 1. In this apparatus, the motor is driven by converting electric power from a battery, which is a power supply source, into three-phase alternating current by an inverter and supplying it to the motor.
The inverter converts electric power by switching operations of a plurality of switching elements. However, as a means for preventing heating of the switching elements at the time of failure, when the temperature reaches a predetermined temperature or more, the motor torque command value is reduced, The drive is stopped and the inverter is protected.
JP-A-10-210790

From the viewpoint of protecting the inverter, it is preferable to reduce the torque of the motor or stop driving the motor.
However, for example, even when the motor being driven is mechanically constrained by a load from the wheel driven by the motor and locked, the inverter is fixed in the switching phase in which some switching elements are turned on. As a result, the heat generated by the switching element fixed in the ON state increases.
If such a locked state occurs when the vehicle stops on a slope, for example, if the motor torque command value is reduced or the motor that was being driven is stopped, the vehicle will roll inadvertently or its rollback may occur. Or become bigger.

Even if it is determined that the motor is locked and the motor torque command is reduced to reduce the energization current to the switching element when locked, the energized switching element remains fixed. The time until stoppage (sustainable time in the motor lock state) is limited to a short time.
The present invention has been made paying attention to the above points, and it is an object of the present invention to make it possible to suppress a decrease in motor torque while suppressing heat generation of the inverter when the motor is locked.

In order to solve the above-described problems, the present invention provides a motor control device that controls the current supplied to the motor armature and the current supplied from the power supply source to the armature of the motor via the inverter.
When it is determined that the rotor of the motor is in a mechanically constrained locked state, the direction of the field current of the motor is reversed, and the upper and lower arms in each phase of the inverter are synchronized with the reversal of the field current. The on / off state of the switching element is switched.

  According to the present invention, the direction of the field current and the direction of the armature current in the motor are reversed together (switching the direction) in synchronization, thereby turning off the switching element in the on state, The torque can be maintained. Further, by switching periodically the switching elements that are energized in each phase with the upper and lower arms, the switching elements that are turned on in each phase are turned on in comparison with the state in which the switching elements that are turned on in each phase are fixed. Time can be halved. That is, the sustainable time of the motor lock state can be made longer compared to the state where the switching elements in the ON state of each phase are fixed.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a four-wheel drive vehicle to which the present invention is applied. FIG. 2 is a configuration diagram of a power electronics unit related to the motor drive control.
(Constitution)
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 can be driven by a motor 4. Is a secondary 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 less than or equal to the opening of the main throttle valve by a command from the engine control unit, independent of the driver's accelerator pedal operation (accelerator opening), The output torque of the engine 2 can be adjusted.

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 according to the field current Ifg adjusted by the 4WD control unit 20, and generates power according to 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.

The electric power generated by the generator 7 can be supplied to the AC motor 4 via the junction box 10 and the inverter 9. That is, the inverter 9 converts direct current into three-phase alternating current and supplies it to the alternating current motor 4 to drive the motor 4. In addition, it is set as the capacitor | condenser input type which installed the small capacitor 15 in parallel with the input circuit.
As shown in FIG. 3, the motor 4 is a field winding type synchronous motor, in which a rotor having a field coil 4a and a three-phase winding (armature coil 4b) for generating a rotating magnetic field are wound. A stator is provided. The motor 4 rotates by the interaction between a magnetic field generated by passing a current through the field coil 3a of the rotor and a magnetic field generated by the armature coil 4b of the stator. Further, when the rotor is rotated by an external force, an electromotive force is generated at both ends of the armature coil 4b due to the interaction of these magnetic fields, and a power generation operation is performed. The motor 4 is controlled to a command value by the motor control unit 21.

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 the junction box 10, a relay for connecting and disconnecting the inverter 9 and the generator 7 is provided. Then, the DC power supplied from the generator 7 via the rectifier 12 with this relay connected is converted into three-phase AC in the inverter 9 to drive the motor 4.
Further, in the junction box 10, a generator voltage sensor 13 for detecting a generated voltage and a generator current sensor 14 for detecting a generated current that is an input current of the inverter 9 are provided. These detection signals are controlled by 4WD. Is output to the unit 20. 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.

  As shown in FIG. 3, the inverter 9 includes six switching elements 9 a (MOSFETs). That is, the six switching elements 9a are divided into three sets of upper and lower arm switching elements 9a corresponding to the three phases of the armature coil 4b of the motor 4, and each of the three sets of switching elements 9a is subjected to switching control. Thus, three-phase alternating current is supplied to the motor 4. The switching control is performed by a command from the motor control unit 21. Further, a current sensor for detecting the current value of each phase converted by the inverter 9, that is, detecting the current of the armature current Ia is provided, and the detected current signal is output to the motor control unit.

  In addition, a field drive circuit 22 is provided for flowing a field current Ifm to the field coil 4 a of the motor 4. The field drive circuit 22 is composed of four switching elements 22a (MOSFETs) that form two sets, and switches in accordance with a command from the motor control unit 21 to change the direction of the field current Ifm and the field current. The magnitude of Ifm is controlled. In addition, a current sensor that detects the current of the field coil 4 a is provided, and a current signal detected by the current sensor is supplied to the motor control unit 21.

The power of the auxiliary battery may be supplied to the field coil 4a of the motor 4 via the field drive circuit 22, or the power converted by the inverter 9 may be supplied to the field drive circuit 22. The field coil 4a of the motor 4 may be energized via the via.
The clutch 12 is a wet multi-plate clutch, for example, and performs fastening and releasing according to a command from the 4WD control unit 20. 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. Each wheel speed sensor outputs a pulse signal corresponding to the rotation speed of the corresponding wheel 1L, 1R, 3L, 3R to the 4WD control unit 20 as a wheel speed detection value.
The 4WD control unit 20 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, a voltage sensor 13 in the junction box 10, and a current sensor 14. An output signal, an output signal of a resolver connected to the motor 4, an accelerator opening corresponding to an amount of depression of an accelerator pedal (not shown) which is a driving force indicator, and the like are input.

As shown in FIG. 4, the 4WD control unit 20 includes a motor command calculation unit 30, a generator control unit 31, and a clutch control unit 32.
As shown in FIG. 5 which is a block diagram, the motor command calculation unit 30 includes a front / rear rotation speed difference calculation unit 30a, a vehicle speed calculation unit 30b, a first motor 4 driving force calculation unit 30c, a second motor 4 driving force calculation unit 30d, The motor torque command value Tt is calculated from the wheel speed difference between the front and rear wheels calculated based on the wheel speed signal of the four wheels and the accelerator pedal opening signal, which includes the select high unit 30e and the rear wheel TCS control unit 30f. .

That is, first, the front-rear rotation speed difference calculation unit 30a 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
Based on the forward / backward rotation difference ΔV, the map stored in advance by the first motor 4 driving force calculation unit 30c is calculated, and the first motor 4 driving force TΔV is calculated and output to the select high unit 30e described later. The first motor 4 driving force TΔV is set such that the front-rear rotation difference ΔV is increased and proportionally larger.

On the other hand, the vehicle speed calculation unit 30b calculates the 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 4 driving force calculation unit 30d calculates the second motor 4 driving force Tv. Specifically, calculation is performed with reference to a map stored in advance based on the vehicle speed V and the accelerator opening Acc output from the vehicle speed calculation unit 30b. The second motor 4 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 30e, the first motor 4 driving force TΔV output from the first motor 4 driving force calculating unit 30c and the second motor 4 driving output from the second motor 4 driving force calculating unit 30d. A value obtained by selecting high the force Tv is output to the rear wheel TCS control unit 30f 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 motor torque command value Tt of the motor 4 is output.
Moreover, the generator control unit 31 includes a required power calculation unit 31A and a generator control unit main body 31B, as shown in FIG. 6 which is a block diagram.
Based on the motor torque command value Tt calculated by the motor command calculation unit 30 and the motor 4 rotation speed Vm, the required power calculation unit 31A, as shown in FIG. The power Pm necessary for the calculation is calculated.
Pm = Tt × Vm

Furthermore, based on the required motor power Pm, the required generator power Pg to be output by the generator 7 is calculated based on the following equation. The generator required power Pg must be output more than the motor required power Pm by the motor / inverter efficiency.
Pg = Pm / Иm
Here, Иm is the motor / inverter efficiency. The motor / inverter efficiency Иm is calculated using an efficiency map based on the motor torque command value Tt and the motor 4 rotational speed Vm.

In the generator control part main body 31B, the process of a block diagram as shown in FIG. 8 is performed. That is, the generator voltage command Vg is calculated by dividing the required power calculated by the required power calculator 31A by the generator current. At this time, if the generator voltage command is larger than the upper limit voltage Vmax (fail voltage) through the voltage limiter 31Ba, the voltage is limited to the upper limit voltage Vmax. The upper limit voltage Vmax is set to 60 V, for example, and is set based on the rating of the switching element 9 a of the inverter 9 and the design of the generator 7 and the motor 4.
Further, the generator voltage command and the generator voltage are compared to determine a voltage deviation, and PI control is performed to determine and output a field current Ifg to be a generator voltage command.

  The gain of the PI control is changed by previously obtaining a P gain map and an I gain map using the generator speed as a parameter. In addition, the FF (feed forward) term is obtained in advance as an FF map using the voltage difference of the generator voltage and the generator rotational speed as parameters, and is added to the PI output value. Although FIG. 8 shows an example in which the generated voltage is controlled, the field current Ifg may be obtained and controlled by detecting (or estimating) the generated field magnetic current.

Moreover, the clutch control part 32 controls the state of the said clutch 12 like FIG. 6, and controls the clutch 12 to a connection state, while determining with the four-wheel drive state. For example, the clutch control unit 32 controls as follows.
・ Clutch on when the vehicle is stopped when the 4WD switch is on ・ Clutch on when the motor target torque is not 0 ・ Clutch off when the motor target torque is 0 ・ Protection when the motor 4 speed exceeds the allowable speed Therefore, the clutch is turned off. · The clutch is turned off when the 4WD switch is turned off. As shown in FIG. 9, the motor control unit 21 includes a motor lock determination unit 21A, a normal inverter drive control unit 21B, a normal motor field control unit 21C, and a lock process. Part 21D.

  The processing of the motor lock determination unit 21A will be described with reference to FIG. The motor lock determination unit 21A is executed at a predetermined sampling period during drive control of the motor 4. First, in step S10, the rotation angle (using an electrical angle or the like) of the motor 4 is detected, and the process proceeds to step S20. In step S20, it is determined whether or not the previous rotation angle is equal to the current rotation angle. If it is determined that the rotation angle is equal, the lock state is determined and the process proceeds to step S30. Migrate to

Steps S10 and S20 constitute a lock state detection means for detecting the lock state of the motor 4. When the motor 4 is not rotating for a predetermined time when the motor 4 is driven, the lock state is determined. It is. In the above processing, it is determined whether or not the lock state is established based on the rotation speed Vm of the motor 4, but it may be determined whether or not the rotation speed of the motor 4 is zero for a predetermined time.
In step S30, the lock flag LKFLG is turned on and the process ends.
In step S40, the lock flag LKFLG is turned off and the process is terminated. Note that the initial value of the lock flag LKFLG is off.

  Further, normally, the inverter drive control unit 21B operates only when the lock flag LKFLG is OFF, and performs known vector control shown in FIG. 11 from the motor torque command value Tt and the rotational speed Vm of the motor 4. Then, the switching control signal of the three-phase power element is output to the inverter 9 to control the three-phase alternating current. Similarly, the normal motor field control unit 21C also operates only when the lock flag LKFLG is off, and performs switching control to the field drive circuit 22 so that the target motor field current obtained based on the rotational speed Vm of the motor 4 is obtained. A signal is output to control the motor field current.

In addition, the process of the said normal inverter drive control part 21B and the normal motor field control part 21C is applicable if it is a control method controlled to a well-known target motor torque.
Further, the lock processing unit 21D includes a field switching unit 41 and an inverter inverting unit 42 as shown in FIG.
The field switching unit 41 operates when the lock flag LKFLG is on, and forcibly switches the direction of the field current Ifm every time a predetermined period, for example, a predetermined time (for example, several tens of milliseconds) elapses. That is, the previous switching pattern of the field coil 4a is stored, and when a predetermined time elapses, the switching control signal for switching the switching element 9a in the on state to the off state and the switching element 9a in the off state to the on state Output to the drive circuit 22. The field switching unit 41 constitutes a field current switching unit.

  The inverter inverting unit 42 operates when the lock flag LKFLG is on, and forcibly inverts the switching pattern of the inverter 9 in synchronization with the field switching unit 41 switching the direction of the field current Ifm. That is, based on the previous switching pattern stored, the on / off state of each switching element 9a is detected, and the on-state switching element 9a is turned off in synchronization with the switching of the direction of the field current Ifm. The switching control signal for switching the switching element 9a in the off state to the on state is output to the inverter 9.

Here, generally, the L value of the field coil 4a is larger than the L value of the armature coil 4b. As a result, the current turn-on time and the turn-off time of the field current Ifm controlled by the field drive circuit 22 are greater than the armature current Ia controlled by the inverter 9.
In view of this, the inverter inverting unit 42 performs the following inversion processing without inverting the switching pattern of the inverter 9 simultaneously with the inversion of the switching pattern by the field switching unit 41.

  That is, when the fact that the field switching unit 41 outputs a switching control signal for switching the switching pattern is input, the field current Ifm is monitored (step S100), as shown in FIG. When it is detected that the absolute value is equal to or less than the predetermined threshold Ifth, the previous switch pattern is stored (step S110), and a switching control signal for turning off all the switching elements 9a of the inverter 9 is output to the inverter 9 ( Step S120). Subsequently, the field current Ifm is monitored (step S130), and when it is detected that the absolute value of the field current Ifm is equal to or greater than a predetermined threshold value Ifth, a switch pattern obtained by inverting the stored previous switch pattern is The switching control signal is output to the inverter 9 (step S140). This process is performed every time the field switching unit 41 outputs a switching control signal for switching the switching pattern. If the motor 4 locked state is released halfway, the above process is stopped. Here, step S140 constitutes a switching inversion means.

(Function and effect)
In the four-wheel drive state in which the motor 4 is driven and controlled, the generated power from the generator 7 is supplied to the armature coil 4b of the motor 4 via the inverter 9, and the current is also supplied to the field current Ifm of the motor 4. Is done.
If the motor 4 is not in a locked state while the vehicle is running or starting normally, the motor torque command value is obtained by normal control (processing of the normal inverter drive control unit 21B and normal motor field control unit 21C). Then, the motor 4 is rotationally driven, and the rear wheel (sub driven wheel) driven by the motor 4 rotates.
On the other hand, when starting on a slope, the motor 4 is mechanically constrained by a load from the rear wheel side (when the motor 4 is driven but the motor 4 is not rotating) The flag LKFLG is turned on, the normal control is stopped, and the lock time processing unit 21D is activated.

  That is, although the motor 4 is in the drive control state, the rotation angle of the motor 4 does not change for a certain period of time. Therefore, it is determined that the motor 4 is in the locked state, and the lock time processing unit 21D is activated, The switching pattern of the field drive circuit 22 and the inverter 9 is reversed every time. The predetermined time for reversal is set to a time T (about several tens of milliseconds as an order) that is sufficiently earlier than the time during which the temperature of the switching element 9a rises in the locked state.

  For example, assume that the energization patterns of the switching element 9a, the motor armature coil 4b, the field coil 4a, and the field drive circuit 22 when the motor 4 is locked are in the state shown in FIG. If energization in this state is continued, the specific switching element 9a remains on, and the temperature of the switching element 9a rapidly increases. Therefore, when the temperature of the switching element 9a rises in the locked state and a sufficiently early time elapses, the energization states of the switching element 9a, the motor 4 armature coil 4b, the field coil 4a, and the field drive circuit 22 are shown in FIG. Switch to the state. Thereafter, the switching operation shown in FIGS. 3 to 13 is repeated until the locked state is released.

At this time, in the state where the switching pattern is reversed as in the relationship between the states in FIGS. 3 and 13, the relative relationship between the directions of the currents flowing through the field coil 4a and the armature coil 4b is not changed. Torque can be output. As a result, even when the motor 4 is in a locked state when starting on a slope, the rollback can be suppressed or the rollback can be reduced.
Further, by periodically switching the ON state of the switching element 9a of the inverter 9 with the upper and lower arms, it is possible to prevent the temperature of only the specific switching element 9a from increasing, and the time for reaching the protection temperature Can also be long.

  That is, by reversing the direction of the field current Ifm and the armature current of the motor 4 in synchronization, the characteristics of the motor 4 are maintained, that is, the lock torque at the time of locking is maintained, and the inverter 9 Since the switching element 9a that is turned on is only periodically switched by the upper and lower arms in each phase, the switching element 9a that is turned on for each phase is controlled in a fixed state. The on-time of the switching element 9a can be halved. Therefore, the lock sustainable time can be made longer than in the conventional example.

  Since the field current Ifm has a larger turn-on time and turn-off time than the electric current, the inverter inverting unit 42 inverts the switching pattern of the field drive circuit 22 and the switching pattern of the inverter 9 at the same time. The switching pattern inversion process of the inverter 9 is performed so that the direction of the field current Ifm and the direction of the armature current always have the same relative relationship.

  That is, by inverting the switching pattern of the field drive circuit 22, the field current Ifm changes toward zero, but the inverter 9 is set so that the armature current becomes zero before the field current Ifm becomes zero. All the switching elements 9a are turned off, and subsequently, the switching pattern of the inverter 9 is switched so as to be opposite to the previous one after detecting that the field current Ifm has been reversed, thereby inverting the switching pattern. As a result, although there is a torque loss only during the time when the armature current is zero, the relative relationship between the direction of the field current Ifm and the armature current is temporarily reversed to be opposite to the driving direction of the motor 4. Generation of torque can be prevented.

FIG. 14 shows a time chart example of the switching operation. It is assumed that the switch pattern when in the locked state is the state shown in FIG.
In this time chart, first, at time t0, the on pattern of the field drive circuit 22 is switched to the state of FIG. 13 by the switch control signal from the field switching unit 41. Then, the current value of the field current Ifm begins to gradually decrease due to the time constant of the field coil 4a. The field current Ifm is monitored, and at time t1 when the field current Ifm reaches a predetermined threshold value Ifth, the switching elements 9a of the inverter 9 are all turned off by the switching control signal from the inverter inverting unit 42. Turn off the child current. At this time, the current value of the armature current starts to decrease due to the time constant of the armature coil 4b. At t2, the armature current becomes zero and the output torque of the motor 4 also becomes zero. Thereafter, the field current Ifm becomes zero at t3. Since the on state of the switching element 9a of the field circuit is switched at the time point t0, the field current Ifm starts to reverse and flow after the elapse of t3. Further, at time t4 when the field current Ifm becomes the predetermined threshold value -Ifth, the switching state on the inverter 9 side is switched to the state shown in FIG. Current also starts to flow in reverse, reaching the same armature current value as before switching the switching element 9a at time t5. The field current Ifm becomes the same value as before the switching at the time of t6 with a delay, and the switching operation is completed. By performing such an operation, the armature current can be surely made zero at the time t3 when the field current Ifm switches, so that the output torque of the motor 4 can be prevented from being output in the reverse direction. . Thereafter, the same operation is continued every switching cycle T until the locked state is released.

Here, how to determine the field current threshold Ifth for determining the timing for outputting the switching control signal from the inverter inverting unit 42 to turn off the armature current will be described.
Since the L value of the field coil 4a is generally larger than the L value of the armature coil 4b, the time when the armature current Ia becomes zero is earlier than the time when the field current Ifm of the field coil 4a becomes zero. . Therefore, first, the armature current Ia0 in the locked state is detected, and the time from when the switch element is changed so that the armature current is turned off by the L value La of Ia0 and the armature coil 4b until it actually becomes zero. ta0 is calculated. The arithmetic expression at this time is represented by the following expression where Ra is the combined resistance value of the armature coil 4b and the inverter unit.
0 = exp (-ta0 / (La / Ra))
Then, the time ta0 is determined from the above equation. However, in general, the current value becomes almost zero in a time of about t = 3 × (La / Ra), and therefore ta0 = 3 × (La / Ra) may be set.

Further, a field current threshold value Ifta0 after ta0 when energization is started from a state where the motor field current Ifm is zero is obtained. Ifta0 is Rf as the combined resistance of the field coil 4a and the field circuit, and Vf as the field power supply voltage.
Ifta0 = Vf / Rf [1-exp {-t / (Lf / Rf)}]
Is required.
A value adjusted by multiplying Ifta0 by a safety factor so that the armature current Ia always becomes zero first is defined as a field current threshold Ifth.
Here, the torque is released during the period when the armature current is off, but if the period is within the period absorbed by the torsion of the drive torque transmission mechanism, the driving force of the rear wheels becomes completely zero by the amount of torsion. This can be reduced.

Since it is desirable that the time when the armature current is zero is short, when it is detected that the field current Ifm is reversed, the switching of the previous time before the absolute value of the field current Ifm becomes equal to or greater than the field current threshold Ifth. A switching control signal having an inverted pattern may be output to the inverter 9.
Further, in the above embodiment, the direction of the field current Ifm is forcibly switched at a constant period. However, the period is set to be inequalities such that the period is gradually shortened according to the lock state. You can also.
In the above embodiment, the motor control device of the present invention is applied to a hybrid vehicle. However, the motor control device of the present invention may be applied to other devices such as an electric vehicle.

It is a schematic structure figure concerning an embodiment based on the present invention. It is a schematic diagram of power electronics concerning an embodiment based on the present invention. It is a figure which shows the structure of the inverter and field drive circuit which concern on embodiment based on this invention. It is a figure which shows the structure of the 4WD control part which concerns on embodiment based on this invention. It is a figure which shows the structure of the motor command calculating part which concerns on embodiment based on this invention. It is a block diagram of the generator control which concerns on embodiment based on this invention. It is a block diagram of the required power calculating part which concerns on embodiment based on this invention. It is a block diagram of the generator control part main body which concerns on embodiment based on this invention. It is a figure which shows the structure of the motor control part which concerns on embodiment based on this invention. It is a figure which shows the process of the motor lock determination part which concerns on embodiment based on this invention. It is a figure which shows the structural example of a normal inverter drive control part. It is a figure which shows the process of the inverter inversion part which concerns on embodiment based on this invention. It is a figure which shows the state after inversion of an inverter and a field drive circuit. It is a figure which shows the example of a time chart which concerns on embodiment based on this invention.

Explanation of symbols

4 Motor 4a Field coil 7 Generator 9 Inverter 9a Switching element 21 Motor control unit 21A Motor lock determination unit 21B Inverter drive control unit 21C Normal motor field control unit 21D Lock time processing unit 22 Field drive circuit 22a Switching element 30 Motor command calculation Unit 31 Generator Control Unit 41 Field Switching Unit 42 Inverter Inversion Unit Ia Armature Current Ifm Field Current Ifth Field Current Threshold LKFLG Lock Flag

Claims (4)

By switching the switching elements of the upper and lower arms corresponding to each phase of the motor, the supply power supplied from the power supply source is converted into AC power and supplied to the motor armature, and is supplied to the motor field coil In a motor control device comprising a field drive circuit for controlling current,
Lock state detecting means for detecting a locked state in which the rotor of the motor is mechanically constrained, field current switching means for reversing the direction of the field current of the motor, and switching elements of all the arms of the inverter being turned on -Switching inversion means for switching the OFF state in synchronization,
When the motor is determined to be in the locked state by the detection of the lock state detection means, the field current switching means reverses the direction of the field current of the motor, and the switching inversion means causes the switching elements of the upper and lower arms in each phase of the inverter to be reversed. A motor control device, wherein the on-off state is switched in synchronization with the reversal of the field current.   When reversing the direction of the field current, if it is detected that the absolute value of the field current has dropped below a predetermined threshold before the direction of the field current is reversed, the switching elements of all the arms of the inverter The motor armature current is stopped by turning off the motor, and when the direction of the field current is reversed, the on / off state of the switching elements of the upper and lower arms of each phase is switched to the inverted state. The motor control device according to claim 1.   3. The motor control device according to claim 2, wherein the predetermined threshold value is a current value that does not reverse the direction of the field current when the stopped motor armature current becomes zero.   The motor control device according to any one of claims 1 to 3 is provided, wherein the power supply source is a generator driven by torque of an internal combustion engine that drives drive wheels, and the torque of the motor A driving force control device for a vehicle, characterized in that the driven wheels are driven.

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