JP6816466B2 - Vehicle control device - Google Patents

Description

The present invention relates to, for example, the technical field of a vehicle control device for controlling a vehicle including an electric motor and an inverter.

Patent Document 1 describes a vehicle control device that controls a vehicle in which at least one of the driving wheels is driven by a prime mover and the other driving wheels are driven by an electric motor. Specifically, the vehicle control device described in Patent Document 1 shuts down an inverter that supplies electric power to an electric motor when controlling other drive wheels driven by the electric motor to a non-driving state. However, in the vehicle control device described in Patent Document 1, the rotation speed of the electric motor becomes equal to or higher than a predetermined threshold value corresponding to the rotation speed at which the counter electromotive voltage of the electric motor matches the voltage between the terminals of the power supply (that is, the reverse of the electric motor). If the electromotive voltage exceeds the terminal voltage of the power supply), shutting down the inverter is prohibited, and field weakening control is performed to cancel the counter electromotive voltage of the motor.

JP-A-2007-161249

In Patent Document 1, the predetermined threshold value is determined based on the backlash constant of the electric motor. Since the backlash constant is a fixed value peculiar to the electric motor, the predetermined threshold value does not fluctuate according to the state of the electric motor. However, in reality, the counter electromotive voltage of the motor fluctuates according to the strength of the magnetic field generated by the field of the motor. Therefore, if the strength of the magnetic field in which the field is generated is estimated and the predetermined threshold value is variably set based on the estimated strength of the magnetic field, the timing is more appropriate than when a fixed value is used as the predetermined threshold value. The inverter can be shut down with.

On the other hand, an error in estimating the strength of the magnetic field may occur. That is, there may be an error between the estimated magnetic field strength and the actual magnetic field strength. In this case, according to the judgment using the predetermined threshold value set based on the estimated magnetic field strength, it is determined that the counter electromotive voltage of the motor does not exceed the voltage between the terminals of the power supply (that is, the inverter can be shut down). Nevertheless, in reality, the back electromotive voltage of the motor may exceed the voltage between the terminals of the power supply. As a result, the electric motor functions as a generator (that is, the electric motor functions as a load on the vehicle), which causes a technical problem that the efficiency of the vehicle deteriorates.

Examples of the problems to be solved by the present invention include the above. The present invention estimates the strength of the field magnetic field of the electric motor, and when the inverter is shut down when the rotation speed of the motor is smaller than the threshold value set based on the estimated magnetic field strength, the efficiency of the vehicle is improved. An object of the present invention is to provide a vehicle control device capable of more appropriately preventing deterioration.

The vehicle control device of the present invention can drive a motor capable of driving the first drive wheel and a second drive wheel different from the first drive wheel by being driven by electric power, or can drive the power of the motor. A vehicle control device that controls a vehicle including an electric motor that can generate power by being driven by using an electric motor and an inverter that converts DC power supplied from a power source into AC power and supplies the electric motor to the electric motor. A case where the estimation means for estimating the strength of the magnetic field generated by the field magnet provided and the countercurrent voltage of the electric motor calculated based on the estimated strength of the magnetic field match the voltage between terminals on the power supply side of the inverter. A setting means for setting the rotation speed of the electric motor to a predetermined threshold value, a determination means for determining whether or not a current is flowing from the electric motor to the inverter, and (i) the electric motor does not need to be driven and When the rotation speed of the electric motor is smaller than the predetermined threshold value, the first control for shutting down the inverter is performed, and (ii) a current flows from the electric motor into the inverter under the situation where the first control is performed. When it is determined that the motor is present, even if the rotation speed of the electric motor is smaller than the predetermined threshold value, the first control is interrupted and the second control for canceling the countercurrent voltage of the electric motor is performed. It is provided with a control means for performing.

According to the vehicle control device of the present invention, when the rotation speed of the motor is smaller than a predetermined threshold value, the counter electromotive voltage of the motor (that is, the estimation of the counter electromotive voltage) calculated based on the strength of the magnetic field estimated by the estimation means Since the value) does not exceed the voltage between the terminals of the inverter, the inverter is shut down. On the other hand, when it is determined that a current is flowing from the motor to the inverter under the condition that the shutdown control is performed, the estimated value of the counter electromotive voltage of the motor does not exceed the voltage between the terminals of the inverter. It is assumed that the actual counter electromotive voltage of the motor has exceeded the voltage between the terminals of the inverter. Therefore, in this case, it is presumed that the electric motor is functioning as a generator, although the estimated value of the counter electromotive voltage of the electric motor does not exceed the voltage between the terminals of the inverter. In this case, a second control is performed to cancel the counter electromotive voltage of the electric motor. Therefore, deterioration of vehicle efficiency due to the function of the electric motor as a generator can be appropriately prevented.

FIG. 1 is a block diagram showing a configuration of a vehicle according to the present embodiment. FIG. 2 is a flowchart showing the flow of the shutdown operation performed by the ECU. FIG. 3 shows the vehicle speed, the magnetic field strength, the rotation speed of the electric motor, the state of the inverter, and the time transition of the current flowing through the electric motor when the current flowing from the electric motor to the inverter is detected while the inverter is shut down. It is a timing chart which shows.

Hereinafter, embodiments of the vehicle control device will be described. Hereinafter, the vehicle 1 to which one embodiment of the vehicle control device of the present invention is applied will be described.

(1) Configuration of Vehicle 1 First, the configuration of vehicle 1 of the present embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the vehicle 1 of the present embodiment.

As shown in FIG. 1, the vehicle 1 includes a prime mover 11f, a reduction gear 12f, a drive shaft 13f, a front wheel 14f which is a specific example of the "first drive wheel", a prime mover 11r, a reduction gear 12r, and the like. It includes a drive shaft 13r, a rear wheel 14r which is a specific example of the "second drive wheel", a DC power supply 15, an inverter 16f, an inverter 16r, a current sensor 17, and an ECU 18.

The prime mover 11f drives the front wheels 14f. Specifically, the prime mover 11f supplies the driving force for driving the vehicle 1 to the front wheels 14f via the reduction gear 12f and the drive shaft 13f. The prime mover 11f includes an engine ENG and an electric motor MGf as a supply source of driving force. The prime mover 11r drives the rear wheels 14r. Specifically, the prime mover 11r supplies the driving force for driving the vehicle 1 to the rear wheels 14r via the reduction gear 12r and the drive shaft 13r. The prime mover 11r includes an electric motor MGr as a source of driving force.

The DC power supply 15 supplies DC power for driving the electric motor MGf to the inverter 16f. Further, the DC power supply 15 supplies DC power for driving the electric motor MGr to the inverter 16r. As an example of the DC power supply 15, for example, a secondary battery (for example, a nickel hydrogen battery, a lithium ion battery, etc.) and a capacitor (for example, an electric double-phase capacitor, a large-capacity capacitor, etc.) are exemplified.

The inverter 16f converts the DC power supplied by the DC power source 15 into AC power. Therefore, the inverter 16f is provided with a switching element for converting DC power into AC power. For example, when the electric motor MGf is a three-phase AC motor, the inverter 16f has two switching elements connected in series and two diodes arranged in parallel with the two switching elements in three phases. We are preparing for each of them. Since an existing inverter (for example, the inverter described in Patent Document 1) can be used as the inverter 16f, detailed description of the structure of the inverter 16f will be omitted. The inverter 16f supplies AC power to the electric motor MGf. The electric motor MGf is driven by using the AC power supplied from the inverter 16f.

The inverter 16r converts the DC power supplied by the DC power source 15 into AC power. Therefore, the inverter 16r is provided with a switching element for converting DC power into AC power. The structure of the inverter 16r is the same as that of the inverter 16f. The inverter 16r supplies AC power to the electric motor MGr. The electric motor MGr is driven by using the AC power supplied from the inverter 16r.

The current sensor 17 detects the current flowing between the electric motor MGr and the inverter 16r. The detection result of the current sensor 17 is output to the ECU 18.

The ECU 18 is an electronic control unit for controlling the operation of the vehicle 1. In particular, in the present embodiment, the ECU 18 performs a shutdown operation for shutting down the inverter 16r as needed.

(2) Flow of Shutdown Operation Subsequently, the shutdown operation by the ECU 18 will be described with reference to FIG. FIG. 2 is a flowchart showing the flow of shutdown operation by the ECU 18.

As shown in FIG. 2, the ECU 18 determines whether or not the required output of the electric motor MGr (that is, the driving force required of the electric motor MGr that the electric motor MGr should supply to the rear wheels 14r) is zero. Determine (step S1). Specifically, the required output of the electric motor MGr is determined by the ECU 18 according to the traveling state of the vehicle 1 together with the required output of the prime mover 11f (that is, the required output of each of the engine EMG and the electric motor MGf). Here, in the present embodiment, the electric motor MGr supplies the driving force to the rear wheels 14r when the traveling state of the vehicle 1 is in the specific state, while the driving force is not in the traveling state of the vehicle 1. Is not supplied to the rear wheel 14r (in other words, it is not necessary to supply). Therefore, when the traveling state of the vehicle 1 is not in the specific state, the electric motor MGr is not driven, and the vehicle 1 travels using the driving force supplied from the prime mover 11f. In this case, the rotor of the electric motor MGr rotates in accordance with the rotation of the rear wheels 14r. On the other hand, when the traveling state of the vehicle 1 is in a specific state, the vehicle 1 uses the driving force supplied from the prime mover 11r (that is, the electric motor MGr) in addition to the driving force supplied from the prime mover 11f. Run. Therefore, when the traveling state of the vehicle 1 is not in the specific state, the required output of the electric motor MGr becomes zero, and when the traveling state of the vehicle 1 is in the specific state, the required output of the electric motor MGr does not become zero. ..

As an example of the specific state, for example, there is a first state in which the driving force required for traveling of the vehicle 1 (that is, the output required by the vehicle 1) is higher than the predetermined output. As another example of the specific condition, the second state in which it is difficult for the vehicle 1 to efficiently transmit the driving force to the road surface only with the front wheels 14r due to the relatively low friction coefficient of the road surface. Can be given.

If it is determined as a result of the determination in step S1 that the required output of the electric motor MGr is not zero (step S1: No), the ECU 18 shuts down the inverter 16r because the electric motor MGr needs to supply the driving force. Can not do it. Therefore, in this case, the ECU 18 ends the shutdown operation shown in FIG. In this case, the ECU 18 controls the inverter 16r so that the electric motor MGr supplies the driving force according to the required output. Further, when the shutdown operation shown in FIG. 2 is completed, the ECU 18 performs the shutdown operation shown in FIG. 2 again after a predetermined period has elapsed. That is, the shutdown operation shown in FIG. 2 is periodically repeated.

On the other hand, when it is determined that the required output of the electric motor MGr is zero as a result of the determination in step S1 (step S1: Yes), the ECU 18 does not need to supply the driving force because the electric motor MGr does not need to supply the driving force. The inverter 16r can be shut down.

On the other hand, as described above, even when the electric motor MGr does not supply the driving force, the rotor of the electric motor MGr rotates in accordance with the rotation of the rear wheels 14r. Therefore, a counter electromotive voltage Vm is generated in the armature of the electric motor MGr due to the rotation of the rotor of the electric motor MGr. If this counter electromotive voltage is larger than the voltage between the input side terminals of the inverter 16r (specifically, the voltage between the terminals on the DC power supply 15 side) VH, a current is applied from the motor MGr to the DC power supply 15 via the inverter 16r. It flows in. That is, the electric motor MGr functions as a generator for charging the DC power source 15. As a result, the electric motor MGr functions as a load on the vehicle 1, and thus the efficiency of the vehicle 1 deteriorates. Further, since a part of the driving force supplied to the front wheels 14f to drive the vehicle 1 is used as kinetic energy to make the electric motor MGr function as a generator, the drive used to drive the vehicle 1 is used. The force may fluctuate. As a result, drivability may deteriorate.

Therefore, in the present embodiment, the ECU 18 actually uses the inverter 16r even when it is determined that the required output of the electric motor MGr is zero in order to prevent the deterioration of the efficiency and the drivability of the vehicle 1. Before shutting down, it is determined whether or not the inverter 16r can be shut down based on the magnitude relationship between the counter electromotive voltage Vm and the voltage VH between the input side terminals (steps S2 to S4). In the example shown in FIG. 1, the input-side terminal voltage VH corresponds to the terminal voltage of the DC power supply 15. On the other hand, when a boost converter is arranged between the DC power supply 15 and the inverter 16r, the voltage VH between the input side terminals is the voltage between the output side terminals of the boost converter (specifically, on the inverter 16r side). It corresponds to the voltage between terminals).

In order to determine whether or not the inverter 16r can be shut down, the ECU 18 first determines the strength of the magnetic field generated by the field magnet (specifically, the permanent magnet, the field coil, etc.) included in the electric motor MGr (specifically, the field coil, etc.). Hereinafter, H (referred to as “magnetic field strength”) is estimated (step S2). Specifically, the ECU 18 uses the voltage of the motor MGr (for example, U-phase voltage, V-phase voltage and W-phase voltage, or d-axis voltage and q-axis voltage) and the current of the motor MGr (for example, U-phase current, etc.). Based on V-phase current and W-phase current, or d-axis current and q-axis current) and other information (for example, control information for controlling vehicle 1 and state parameters indicating the state of vehicle 1). , Estimate the magnetic field strength H. As a method for estimating the magnetic field strength H, an existing method (for example, the method described in JP-A-8-103093) can be adopted, and therefore detailed description thereof will be omitted here.

After that, the ECU 18 sets the rotation speed ω0 of the electric motor MGr when the counter electromotive voltage Vm matches the voltage VH between the input side terminals to the threshold value TH based on the magnetic field strength H estimated in step S2 (step S3). .. Specifically, the counter electromotive voltage Vm is proportional to "magnetic field strength H x rotation speed ω of electric motor MGr". Therefore, when the counter electromotive voltage Vm matches the voltage VH between the input side terminals, the relationship “H × ω × A (where A is a coefficient) = VH” is established. Solving this formula for the number of revolutions ω gives the solution ω0 = VH / (H × A). Therefore, ω0 = VH / (H × A) is set in the threshold value TH.

After that, the ECU 18 determines whether or not the rotation speed ω of the electric motor MGr is smaller than the threshold value TH set in step S3 (step S4).

As a result of the determination in step S4, when it is determined that the rotation speed ω of the electric motor MGr is not smaller than the threshold value TH (step S4: No), the relationship of ω ≧ TH = ω0 = VH / (H × A) is established. Therefore, the counter electromotive voltage Vm (= H × ω × A) becomes equal to or higher than the input side terminal voltage VH. Therefore, the electric motor MGr functions as a generator for charging the DC power source 15. In this case, the ECU 18 performs field weakening control for canceling the counter electromotive voltage Vm instead of shutting down the inverter 16r (step S7). The field weakening control is a specific example of the "second control". Specifically, the ECU 18 controls the electric motor MGr so as to weaken the magnetic field generated by the field of the electric motor MGr and cancel the counter electromotive voltage Vm. Since the existing weakening field control (for example, the weakening field control described in Patent Document 1) can be adopted for the weakening field control itself, detailed description of the weakening field control will be omitted. As a result, the counter electromotive voltage Vm of the electric motor MGr is canceled out, so that the electric motor MGr does not function as a generator. Therefore, deterioration of the efficiency of the vehicle 1 and deterioration of drivability are appropriately prevented. After that, the ECU 18 ends the shutdown operation shown in FIG. 2 while performing the weakening magnetic field control, and after a predetermined period elapses, performs the shutdown operation shown in FIG. 2 again.

On the other hand, when it is determined that the rotation speed ω of the electric motor MGr is smaller than the threshold value TH as a result of the determination in step S4 (step S4: Yes), it is said that ω <TH = ω0 = VH / (H × A). Since the relationship is established, the counter electromotive voltage Vm (= H × ω × A) becomes smaller than the input-side terminal voltage VH. In this case, the electric motor MGr does not function as a generator for charging the DC power source 15 even if the field weakening control described above is not performed. Therefore, the ECU 18 performs shutdown control for shutting down the inverter 16r (step S5). The shutdown control is a specific example of the "first control". Specifically, the ECU 18 controls the inverter 16r so that all the switching elements included in the inverter 16r are turned off. As a result, not only does the electric motor MGr not function as a generator, but also the ECU 18 does not have to perform field weakening control to cancel the counter electromotive voltage Vm, resulting in deterioration of the efficiency of the vehicle 1 and drivability. Deterioration is properly prevented.

After the inverter 16r is shut down, the ECU 18 determines whether or not the current flowing from the electric motor MGr into the inverter 16r is detected by the current sensor 17 (step S6).

Here, the inverter 16r is shut down when it is determined that the rotation speed ω of the electric motor MGr is smaller than the threshold value TH (that is, the counter electromotive voltage Vm is smaller than the input side terminal voltage VH). Therefore, normally, the current flowing from the electric motor MGr to the inverter 16r should not be detected by the current sensor 17 during the period when the inverter 16r is shut down. However, as described above, the threshold TH is set based on the estimated magnetic field strength H. Therefore, depending on the estimation accuracy of the magnetic field strength H, an error may occur between the estimated magnetic field strength H and the actual magnetic field strength H. That is, there is a possibility that an estimation error of the magnetic field strength H may occur. When the estimation error of the magnetic field strength H occurs, the actual counter electromotive voltage Vm is smaller than the input side terminal voltage VH even when it is determined that the rotation speed ω of the motor MGr is smaller than the threshold value TH. It may not be. Specifically, when the estimated magnetic field strength H is smaller than the actual magnetic field strength H, the threshold value TH set based on the estimated magnetic field strength H is set based on the actual magnetic field strength H. It becomes larger than the threshold TH. Therefore, even if it is determined that the rotation speed ω of the electric motor MGr is smaller than the threshold value TH affected by the estimated miscalculation, the rotation speed ω of the electric motor MGr is not affected by the estimated miscalculation. It may be greater than the threshold TH. As a result, even when it is determined that the rotation speed ω of the motor MGr is smaller than the threshold value TH affected by the estimation miscalculation, the actual counter electromotive voltage Vm is larger than the input side terminal voltage VH ( That is, there is a possibility that a current flows from the electric motor MGr to the inverter 16r).

Therefore, if it is determined that the current flowing from the electric motor MGr to the inverter 16r is detected as a result of the determination in step S6 (step S6: Yes), the “rotation speed ω of the electric motor MGr is from the threshold value TH” in step S4. The determination result of "is also small" is presumed to be an erroneous determination due to an estimation error. Therefore, although the inverter 16r is shut down, it is estimated that the electric motor MGr is functioning as a generator for charging the DC power source 15. Even when the inverter 16r is shut down, the current from the electric motor MGr can be supplied to the DC power supply 15 via the diode of the inverter 16r. In this case, the ECU 18 interrupts the shutdown of the inverter 16r, and then performs field weakening control for canceling the counter electromotive voltage Vm (step S7). As a result, even when the estimation error of the magnetic field strength H occurs, the efficiency of the vehicle 1 deteriorates due to the electric motor MGr continuing to function as a generator for charging the DC power source 15 (furthermore, Deterioration of drivability) is appropriately prevented.

On the other hand, if it is determined as a result of the determination in step S6 that the current flowing from the electric motor MGr to the inverter 16r is not detected (step S6: No), the ECU 18 performs the operations after step S4. That is, the ECU 18 keeps shutting down the inverter 16r until it is determined that the rotation speed ω of the electric motor MGr is not smaller than the threshold value TH.

Here, with reference to FIG. 3, a specific example of the operation performed when the current flowing from the electric motor MGr to the inverter 16r is detected while the inverter 16r is shut down will be described. FIG. 3 shows the vehicle speed of the vehicle 1, the magnetic field strength H, the rotation speed ω of the electric motor MGr, the state of the inverter 16r, and the electric motor when the current flowing from the electric motor MGr to the inverter 16r is detected while the inverter 16r is shut down. It is a timing chart which shows each time transition of the electric current which flows through MGr.

As shown in FIG. 3, it is assumed that the vehicle 1 starts at time t31 and then the vehicle 1 accelerates. Immediately after the vehicle 1 starts, it is assumed that the driver depresses the accelerator pedal relatively deeply in order to strongly accelerate the vehicle 1. As a result, immediately after the vehicle 1 starts, the state of the vehicle 1 is assumed to be a specific state in which the driving force required for the traveling of the vehicle 1 is higher than the predetermined output. Therefore, after the time t31, the vehicle 1 travels using the driving force supplied from the prime mover 11r (that is, the electric motor MGr) in addition to the driving force supplied from the prime mover 11f. Therefore, after the time t31, the inverter 16r is driven (that is, it is not shut down), and the electric motor MGr is supplied with a current from the inverter 16r. Further, as the vehicle 1 accelerates, the vehicle speed and the rotation speed ω of the electric motor MGr increase.

After that, at time t32, it is assumed that the driver releases the accelerator pedal. As a result, after the time t32, the state of the vehicle 1 is not in the specific state that the driving force required for the running of the vehicle 1 is higher than the predetermined output. Further, at time t32, the rotation speed ω of the electric motor MGr is smaller than the threshold value TH set based on the estimated magnetic field strength H. Therefore, the inverter 16r is shut down at the time t32. As a result, after the time t32, the vehicle 1 travels using the driving force supplied from the prime mover 11f. It is assumed that the vehicle 1 accelerates even after the time t32.

Here, as shown in the second graph of FIG. 3, the estimated magnetic field strength H is smaller than the actual magnetic field strength H due to the estimation error of the magnetic field strength H. In this case, as shown in the third graph of FIG. 3, the threshold value TH (hereinafter referred to as “estimated threshold value TH0”) set based on the estimated magnetic field strength H is based on the actual magnetic field strength H. It becomes larger than the original threshold value TH (hereinafter referred to as “actual threshold value TH1”) that is set. Therefore, at the time t33 when the inverter 16r is shut down, it is determined that the rotation speed ω of the electric motor MGr is smaller than the estimated threshold value TH0 even though the rotation speed ω of the electric motor MGr is larger than the actual threshold value TH1. I will continue. Therefore, after the time t33, the electric motor MGr functions as a generator for charging the DC power source 15 even though the inverter 16r is shut down. As a result, after time t33, a current flows from the electric motor MGr toward the inverter 16r. Note that FIG. 3 defines the current flowing from the inverter 16r into the electric motor MGr as a positive current.

After that, at time t34, it is assumed that the current flowing from the electric motor MGr to the inverter 16r is detected. As a result, at time t34, the shutdown of the inverter 16r is interrupted, and field weakening control for canceling the counter electromotive voltage Vm is performed. Therefore, after the time t34, the current flowing from the electric motor MGr to the inverter 16r is canceled by the field weakening control.

If the current flowing from the electric motor MGr to the inverter 16r is not monitored by the ECU 18, the rotation speed ω of the electric motor MGr becomes larger than the estimated threshold value TH0, as shown by the thick dotted line in the fourth graph of FIG. The inverter 16r continues to be shut down until the determined time t35. Therefore, as shown by the thick dotted line in the fifth graph of FIG. 3, the current continues to flow from the electric motor MGr to the inverter 16r (that is, the electric motor MGr continues to function as a generator for charging the DC power source 15. ). Therefore, the efficiency of the vehicle 1 during the period from the time t34 to the time t35 may deteriorate (furthermore, the drivability also deteriorates). However, according to the shutdown operation of the present embodiment, deterioration of the efficiency of the vehicle 1 (furthermore, deterioration of drivability) during the period from the time t34 to the time t35 is appropriately prevented.

In the above description, the electric motor MGr is an electric motor for driving the rear wheels 14r. However, instead of driving the rear wheels 14r (in other words, connected to the axle 13r), the electric motor MGr generates electricity by rotating the rotor using the driving force of the prime mover 11f (particularly, the engine ENG). It may be a possible electric motor (ie, a generator). In this case, if it is assumed that the rotor of the motor MGr can rotate even when the motor MGr does not generate power (that is, the rotor of the motor MGr does not rotate using the driving force of the prime mover 11f). , The ECU 18 may perform a shutdown operation for shutting down the inverter 16r. Specifically, when the electric motor MGr does not generate electricity using the driving force of the prime mover 11f, the ECU 18 operates in the same manner as when it is determined that the required output of the electric motor MGr is zero (from step S2 in FIG. 2). By performing the operation in step S7), shutdown control and field weakening control may be performed.

For example, as an example of a vehicle equipped with an electric motor MGr capable of generating electricity, a so-called split type hybrid vehicle (for example, a hybrid vehicle equipped with a THS (Toyota Hybrid System)) can be mentioned. In this hybrid vehicle, an electric motor MGr that mainly operates as a generator, an electric motor MGf that mainly drives a front wheel 14f (or a driving wheel), and an engine ENG are mechanically arranged via a power split mechanism (for example, a planetary gear mechanism). Are connected. Therefore, even when the electric motor MGr does not generate power (that is, the rotor of the electric motor MGr does not rotate using the driving force of the motor 11f), the rotor of the electric motor MGr keeps the electric motor MGf in accordance with the rotation of the front wheels 14f. The rotor of MGr can rotate, and the rotor of MGr can also rotate in accordance with the rotation of the electric motor MGf. As a result, the back electromotive voltage Vm of the motor MGr becomes equal to or higher than the voltage VH between the input side terminals of the inverter 15r (that is, the motor MGr) even though the motor MGr should not generate power (or does not need to generate power). May unintentionally function as a generator). Therefore, even in this case, the various effects described above can be enjoyed by performing the shutdown operation described above.

The present invention is not limited to the above-described embodiment, and can be appropriately modified within the scope of claims and within a range not contrary to the gist or idea of the invention that can be read from the entire specification, and the vehicle control device accompanied by such a modification. Is also included in the technical scope of the present invention.

1 Vehicle 11f, 11r Motor 14f Front wheel 14r Rear wheel 15 DC power supply 16r Inverter 18 ECU
ENG engine MGf, MGr electric motor

Claims (1)

A prime mover that can drive the first drive wheel,
An electric motor that can drive a second drive wheel different from the first drive wheel by being driven by electric power or can generate electricity by being driven by the power of the prime mover.
A vehicle control device that controls a vehicle equipped with an inverter that converts DC power supplied from a power source into AC power and supplies it to the electric motor.
An estimation means for estimating the strength of the magnetic field generated by the field magnet provided in the electric motor, and
A setting means for setting the rotation speed of the electric motor to a predetermined threshold value when the counter electromotive voltage of the electric motor calculated based on the estimated magnetic field strength matches the voltage between terminals on the power supply side of the inverter. ,
A determination means for determining whether or not a current is flowing from the electric motor to the inverter,
(I) When the electric motor does not need to be driven and the rotation speed of the electric motor is smaller than the predetermined threshold value, the first control for shutting down the inverter is performed, and (ii) the first control is performed. When it is determined that a current is flowing from the electric motor to the inverter under the circumstances, even if the rotation speed of the electric motor is smaller than the predetermined threshold value, the first control is interrupted and then the first control is interrupted. A vehicle control device including a control means for performing a second control for canceling a counter electromotive voltage of an electric motor.

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