JP7433698B2 - motor control device - Google Patents

Description

The present invention relates to a motor control device used in a vehicle.

2. Description of the Related Art Conventionally, vehicles that employ hybrid systems in their drive systems, so-called hybrid vehicles (HV), have been known.

In an example of a hybrid system, engine power is converted to electric power by a power generation motor (MG1), and that electric power is used to drive a drive motor (MG2), and the power of the drive motor is then transferred to the drive wheels. communicated. Furthermore, when the vehicle is decelerating, the drive motor is operated regeneratively, so that the power transmitted from the drive wheels to the drive motor is converted into electric power. At this time, the drive motor acts as a resistance in the travel drive system, and this resistance acts as a braking force (regenerative braking force) that brakes the vehicle. Electric power generated by the drive motor is stored in a battery and used to drive the drive motor. This improves the fuel efficiency of the vehicle.

However, when the SOC (State of Charge), which is the ratio of the remaining charge to the charge capacity of the battery, reaches its upper limit, the battery can no longer accept power. In order to avoid this, it has been proposed that when the SOC of the battery reaches a certain value, the electric power generated by regenerative operation of the drive motor is used to drive the power generation motor to motor the engine.

Japanese Patent Application Publication No. 2012-6525 Japanese Patent Application Publication No. 2011-11714 Japanese Patent Application Publication No. 2010-143310

However, if the amount of power generated by the drive motor is greater than the amount of power consumed by the power generation motor due to motoring of the engine, the SOC of the battery will reach the upper limit even if motoring is performed. In this case, the regenerative operation of the drive motor has to be restricted, and this restriction reduces the regenerative braking force and lowers the deceleration, giving a sense of discomfort to the driver of the vehicle.

An object of the present invention is to provide a motor control device that can prevent a value representing the state of charge of a battery from reaching an upper limit.

In order to achieve the above object, a motor control device according to the present invention provides a vehicle equipped with a motor capable of converting engine power into electric power and motoring the engine, and a battery charged by the electric power generated by the motor. A motor control device used in a motor control device, in which a value representing the state of charge of a battery exceeds a motoring start value set within the range between its upper limit and lower limit, the motor controls the engine motor by the motor. The motoring start value setting means detects a factor that increases a value representing the state of charge of the battery and variably sets a motoring start value in accordance with the factor.

According to this configuration, a factor that increases the value representing the state of charge of the battery is detected, and the motoring start value is variably set in accordance with the detected factor. Then, when the value representing the state of charge of the battery exceeds the motoring start value, motoring of the engine by the motor is executed.

If a large increase in the value representing the state of charge of the battery is expected from the factor, the motoring start value is set low, making it easier for the motor to motor the engine. As a result, the amount of power consumed by motoring increases, so it is possible to prevent the value representing the state of charge of the battery from reaching the upper limit.

The motor is a power generation motor, and the vehicle is a drive system that converts the power generated by the power generation motor or battery power during power running into power for driving the vehicle, and converts the power of the vehicle into power through regenerative operation. It may be further equipped with a motor for use. In this case, the motoring execution means executes motoring of the engine by the generation motor when the value representing the state of charge of the battery exceeds the motoring start value regardless of the operating status of the drive motor. is preferred.

According to this configuration, whether the drive motor is in regenerative operation or powering operation, if the value representing the state of charge of the battery exceeds the motoring start value, , motoring of the engine by the generator motor is executed. Motoring is performed when the drive motor is in power running and the remaining charge of the battery is expected to increase (increase in the value representing the state of charge) due to subsequent regenerative operation of the drive motor. Therefore, it is possible to prepare for an increase in the remaining charge amount, and it is possible to satisfactorily suppress the value representing the state of charge of the battery from reaching the upper limit due to an increase in the remaining charge amount.

The factor may be the altitude of the vehicle's location, the slope of the road surface on which the vehicle is running, or the regenerated power generated by regenerative operation of the drive motor, or a combination thereof.

For example, when a vehicle equipped with a drive motor descends from high ground to flat ground, the higher the altitude at which the vehicle is located, the greater the amount of power generated through regenerative operation of the drive motor. Further, when a vehicle continuously travels on a road surface with a downward slope, the greater the downward slope, the greater the amount of power generation due to regenerative operation of the drive motor.

Therefore, the greater the altitude of the location of the vehicle, the smaller the motoring start value is set. Furthermore, the motoring start value is set to a smaller value as the downward slope of the road surface on which the vehicle travels is greater. This increases the chances of motoring, and as power is forcibly consumed by motoring, the higher the altitude of the vehicle's location and the steeper the slope of the road the vehicle is traveling on, the faster the battery will charge. The remaining amount can be reduced. As a result, it is possible to prevent the value representing the state of charge of the battery from reaching the upper limit.

According to the present invention, since it is possible to prevent the value representing the state of charge of the battery from reaching the upper limit, it is possible to prevent the regenerative braking force from decreasing due to restrictions on the regenerative operation of the drive motor when braking the vehicle. It is possible to prevent the driver of the vehicle from feeling uncomfortable due to a decrease in the regenerative braking force.

1 is a block diagram showing the configuration of a vehicle that employs a hybrid system according to an embodiment of the present invention. It is a flowchart which shows the flow of motoring control processing. FIG. 3 is a diagram showing a forced consumption start SOC map. FIG. 3 is a diagram showing a forced consumption engine rotation speed map. It is a figure which shows an example of the time change of regeneration/power consumption, SOC, and motoring rotation speed. FIG. 3 is a diagram showing the relationship between accelerator release amount, vehicle speed, and regenerated power.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

<Hybrid system configuration>
FIG. 1 is a block diagram showing the configuration of a vehicle 1 employing a hybrid system according to an embodiment of the present invention.

The vehicle 1 employs a series hybrid system, and is equipped with an engine (E/G) 11, a power generation motor (MG1) 12, and a drive motor (MG2) 13. Note that the method of the hybrid system is not limited to the series method, but may be a series/parallel method.

The engine 11 is, for example, a gasoline engine, and includes an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 11, an injector (fuel injection device) for injecting fuel into the intake air, and an electric discharge that generates an electric discharge in the combustion chamber. It is equipped with a spark plug etc.

The power generation motor 12 is, for example, a permanent magnet synchronous motor. The rotation shaft of the power generation motor 12 is mechanically connected to the crankshaft of the engine 11. The power generation motor 12 is used as a starter motor for cranking the engine 11 when the engine 11 is stopped. After the engine 11 is started, the power generation motor 12 can function as a generator that converts the power of the engine 11 into electric power.

The drive motor 13 is, for example, a permanent magnet synchronous motor larger than the power generation motor 12. The rotating shaft of the drive motor 13 is connected to a power transmission mechanism. The power transmission mechanism includes a differential gear, and the power of the drive motor 13 is transmitted to the differential gear, and from the differential gear is distributed and transmitted to drive wheels 14 consisting of left and right front wheels or rear wheels.

The vehicle 1 includes a PCU (Power Control Unit) 15 having a built-in inverter, a microcomputer, etc. for driving a power generation motor 12 and a drive motor 13, respectively, and a plurality of secondary batteries. A driving battery (BAT) 16, which is a battery pack made up of a combination of batteries, is installed.

The PCU 15 is connected to a driving battery 16. AC power generated by the power generation motor 12 is converted into DC power by the PCU 15 and supplied to the drive motor 13 as drive power. Further, surplus power is stored in the driving battery 16. The power stored in the drive battery 16 is converted from DC power to AC power by the PCU 15, and can be supplied to the power generation motor 12 and the drive motor 13 as drive power.

The vehicle 1 is further equipped with an ECU (Electronic Control Unit) including a microcomputer. Although only one ECU 17 for controlling the PCU 15 is shown in FIG. 1, the vehicle 1 is equipped with a plurality of ECUs for controlling each part. A plurality of ECUs including the ECU 17 are connected to enable bidirectional communication using a CAN (Controller Area Network) communication protocol.

Various sensors necessary for control by the ECU 17 are connected to the ECU 17. The various sensors include a vehicle speed sensor 21, a G sensor 22, and an atmospheric pressure sensor 23.

The vehicle speed sensor 21 includes, for example, a rotor made of a magnetic material that rotates as the vehicle 1 travels, and an electromagnetic pickup provided without contact with the rotor, and receives an output from the electromagnetic pickup each time the rotor rotates by a certain angle. Outputs a pulse signal. The frequency of this pulse signal corresponds to the actual speed of the vehicle 1. The ECU 17 determines the frequency of the pulse signal input from the vehicle speed sensor 21, and converts the frequency into a vehicle speed.

The G sensor 22 outputs a signal corresponding to the displacement of the weight as a detection signal corresponding to the acceleration of the vehicle 1. The ECU 17 can determine the acceleration of the vehicle 1 from the detection signal of the G sensor 22. The acceleration determined from the detection signal of the G sensor 22 includes an acceleration component due to a change in vehicle speed and an acceleration component due to the gradient of the road surface on which the vehicle 1 is traveling. On the other hand, the acceleration obtained by differentiating the vehicle speed determined from the detection signal of the vehicle speed sensor 21 is only an acceleration component due to a change in vehicle speed. Therefore, by calculating the difference between the acceleration determined from the detection signal of the G sensor 22 and the differential value of the vehicle speed, the acceleration component due to the road surface slope can be obtained. Based on the acceleration component, the ECU 17 estimates the road surface slope. I can do it.

The atmospheric pressure sensor 23 outputs a detection signal according to atmospheric pressure. As altitude (altitude) increases, atmospheric pressure decreases. Therefore, the ECU 17 can estimate the altitude at the location of the vehicle 1 from the detection signal of the atmospheric pressure sensor 23. Note that if the location information of the vehicle 1 can be obtained, such as when the vehicle 1 is equipped with a navigation device, the altitude of the location of the vehicle 1 may be obtained from the location information.

The ECU 17 controls the PCU 15 based on information acquired from detection signals of various sensors and information input from other ECUs, and controls input/output of electric power to and from the drive battery 16.

<Motoring control processing>
FIG. 2 is a flowchart showing the flow of motoring control processing. FIG. 3 is a diagram showing a forced consumption start SOC map. FIG. 4 is a diagram showing a forced consumption engine rotation speed map.

While the vehicle 1 is running, when the accelerator pedal is released from the depressed state, that is, when the accelerator is released, the ECU 17 controls the regenerative operation of the drive motor 13.

A normal regeneration mode and a strong regeneration mode are set as control modes for regeneration operation. In order to switch between the normal regeneration mode and the strong regeneration mode, a regeneration selector switch is provided, for example, at a position that can be operated by a driver seated in a driver's seat in the vehicle interior. Each time the regeneration changeover switch is pressed, the ECU 17 switches the control mode of the regeneration operation between the normal regeneration mode and the strong regeneration mode. In the normal regeneration mode, the power generated by the regenerative operation of the drive motor 13 does not exceed the power consumed by the motoring of the engine 11 by the power generation motor 12. On the other hand, in the strong regeneration mode, the power generated by the regenerative operation of the drive motor 13 may exceed the power consumption by motoring the engine 11 by the power generation motor 12.

While the vehicle 1 is running, the ECU 17 executes motoring control processing at a predetermined cycle.

In the motoring control process, first, a forced consumption start SOC is set (step S1). The forced consumption start SOC is a threshold value at which the power generation motor 12 starts motoring the engine 11, that is, a threshold value at which the power generation motor 12 starts forced consumption of the power of the drive battery 16 by motoring. The SOC is the ratio of the remaining charge to the charge capacity of the drive battery 16, and is constantly monitored by the ECU 17.

The forced consumption start SOC map shown in FIG. 3 is used to set the forced consumption start SOC. The forced consumption start SOC map is a map that defines the relationship between the altitude of the location of the vehicle 1 and the gradient of the road surface on which the vehicle 1 is located, and the forced consumption start SOC. The forced consumption start SOC map is set such that the forced consumption start SOC is set to a smaller value as the altitude of the location of the vehicle 1 is higher, and the forced consumption start SOC is set to a smaller value as the downward slope of the road surface on which the vehicle 1 is traveling is larger. It is created to be set to . When the vehicle 1 is located on level ground, the forced consumption start SOC is set to the SOC upper limit value in normal charging control or a value close to it. The forced consumption start SOC map is stored in a nonvolatile memory built into the microcomputer of the ECU 17.

Once the forced consumption start SOC is set according to the forced consumption start SOC map, the difference (SOC difference) between the set forced consumption start SOC and the current SOC of the drive battery 16 is calculated (step S2 ).

Further, it is determined whether the current SOC of the driving battery 16 is higher than the forced consumption start SOC (step S3). If the current SOC is higher than the forced consumption start SOC (YES in step S3), the forced consumption engine rotation speed is set according to the current vehicle speed and the SOC difference (step S4). The forced consumption engine rotation speed is the engine rotation speed when the engine 11 is motored by the power generation motor 12.

A forced consumption engine rotation speed map shown in FIG. 4 is used to set the forced consumption engine rotation speed. The forced consumption engine rotation speed map is a map that defines the relationship between the vehicle speed and SOC difference and the forced consumption engine rotation speed. The forced consumption engine speed map is created in such a way that the higher the vehicle speed, the higher the forced consumption engine speed is set, and the larger the SOC difference, the higher the forced consumption engine speed is set. ing. Note that the forced consumption engine rotation speed map may be a map that defines the relationship between the vehicle speed and the forced consumption engine rotation speed.

Then, the supply of drive power from the drive battery 16 to the power generation motor 12 is controlled so that the engine 11 rotates at the set forced consumption engine rotation speed, and the motoring of the engine 11 by the power generation motor 12 is controlled. is executed (step S5).

On the other hand, if the current SOC is below the forced consumption start SOC (NO in step S3), motoring of the engine 11 by the power generation motor 12 is not executed, and the engine 11 remains stopped (step S6).

FIG. 5 is a diagram showing an example of changes over time in regeneration/power consumption, SOC, and motoring rotation speed.

For example, during a period when the SOC of the drive battery 16 is below the forced consumption start SOC, the power generation motor 12 does not motor the engine 11 . When the SOC of the drive battery 16 exceeds the forced consumption start SOC (time T1) due to power generation by the regenerative operation of the drive motor 13, motoring of the engine 11 by the power generation motor 12 is started. As a result, even if the regenerative operation of the drive motor 13 is continued, the motoring is not executed (the change in SOC in this case is shown by the chain double-dashed line). Increase in SOC is suppressed.

Thereafter, even if the drive motor 13 changes from regenerative operation to power running (time T2), as long as the SOC of the drive battery 16 exceeds the forced consumption start SOC, the motoring of the engine 11 by the power generation motor 12 continues. This continues, and the power of the driving battery 16 is forcibly consumed.

Continuation of motoring causes the SOC of the drive battery 16 to drop below the forced consumption start SOC, whereas under control in which motoring is not executed, the SOC of the drive battery 16 drops to the upper limit guard due to regenerative operation of the drive motor 13. approach. Therefore, in the control in which motoring of the engine 11 by the power generation motor 12 is executed, it is possible to implement a strong regenerative operation that generates power exceeding the power consumed by motoring (time T4-T5, time T6 -T7) In control where motoring is not performed, implementation of strong regenerative operation is restricted.

<Effect>

As described above, factors such as the altitude of the location of the vehicle 1 and the slope of the road surface on which the vehicle 1 is located, which are expected to cause an increase in the remaining charge of the drive battery 16, are detected, and the enforcement is applied according to the detected factors. If the consumption start SOC (an example of a motoring start value) is set and the SOC representing the state of charge of the drive battery 16 exceeds the forced consumption start SOC, it is determined whether the drive motor 13 is in regenerative operation or in power running. Regardless of whether the power generation motor 12 is running or not, the engine 11 is motored by the power generation motor 12, and electric power is forcibly consumed by the motoring.

When the vehicle 1 descends from high ground to flat ground, the higher the altitude at which the vehicle 1 is located, the greater the amount of power generated by the regenerative operation of the drive motor 13, which increases the remaining charge of the drive battery 16, that is, increases the SOC. is expected. Furthermore, when the vehicle 1 continuously travels on a road surface with a downward slope, the greater the downward slope, the greater the amount of power generated by the regenerative operation of the drive motor 13, so in this case as well, the SOC of the drive battery 16 increases. expected.

Therefore, the higher the altitude of the location of the vehicle 1, the smaller the forced consumption start SOC is set. Furthermore, the greater the slope of the road surface on which the vehicle 1 is traveling, the smaller the forced consumption start SOC is set. This increases the number of opportunities for motoring of the engine 11 by the power generation motor 12, and the motoring allows power to be actively and forcibly consumed. By motoring the engine 11 by the power generation motor 12 during power running of the drive motor 13, the remaining charge of the drive battery 16 can be actively reduced, and the altitude at the location of the vehicle 1 can be reduced. The larger the gradient is, and the greater the slope of the road surface on which the vehicle 1 travels, the smaller the remaining charge of the drive battery 16 can be. Furthermore, even if power generation is not performed through regenerative operation of the drive motor 13, if the forced consumption start SOC is set to a small value due to an increase in altitude or gradient, the SOC of the drive battery 16 will exceed the forced consumption start SOC. The engine 11 is actively motored by the power generation motor 12. As a result, even if a strong regenerative operation is performed in which the amount of power generated by the regenerative operation of the drive motor 13 exceeds the amount of power consumed by the motoring of the engine 11 by the power generation motor 12, the SOC of the drive battery 16 is Reaching the upper limit can be suppressed.

In addition, the larger the SOC difference between the SOC of the drive battery 16 and the forced consumption start SOC, the larger the forced consumption engine rotation speed, which is the target engine rotation speed when motoring the engine 11 by the power generation motor 12, is set to a larger value. be done. As a result, the power consumption of the power generation motor 12 increases, the power consumption of the drive battery 16 increases, and the SOC of the drive battery 16 can be quickly lowered.

Furthermore, the higher the vehicle speed, the higher the forced consumption engine rotation speed is set. Thereby, the higher the vehicle speed, the louder the engine sound when the engine 11 is motored by the power generation motor 12, so it is possible to improve the feeling of the engine sound.

<Modified example>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms.

For example, in the above-described embodiment, the higher the altitude of the location of the vehicle 1, the smaller the forced consumption start SOC is set, and the greater the downward gradient of the road surface on which the vehicle 1 is traveling, the smaller the forced consumption start SOC is set to. Suppose that it is set to . However, the forced consumption start SOC may be set to a smaller value as the altitude of the location of the vehicle 1 increases, regardless of the gradient of the road surface on which the vehicle 1 is traveling. Furthermore, regardless of the altitude at which the vehicle 1 is located, the forced consumption start SOC may be set to a smaller value as the downward gradient of the road surface on which the vehicle 1 travels is greater.

Note that the slope parameter used to set the forced consumption start SOC may be the value of the slope itself, or a value corresponding to the slope, such as the value of deceleration resistance found from the deceleration torque and vehicle speed. good.

Further, during regenerative operation of the drive motor 13, the forced consumption start SOC may be set according to the regenerated power generated by the regenerative operation. The regenerated electric power is determined by the amount of return of the accelerator pedal from the depressed state (accelerator return amount) and the vehicle speed. That is, as shown in FIG. 6, the regenerative power increases as the amount of return of the accelerator pedal increases, and also increases as the vehicle speed decreases, and the vehicle 1 stops due to the strong regenerative operation of the drive motor 13. It reaches its maximum just before. Therefore, the forced consumption start SOC during regenerative operation of the drive motor 13 may be set according to the regenerated electric power, but may also be set according to the accelerator release amount and/or the vehicle speed.

In addition, various design changes can be made to the above-described configuration within the scope of the claims.

1: Vehicle 11: Engine 12: Power generation motor (motor)
16: Drive battery (battery)
17: ECU (motor control device, motoring execution means, motoring start value setting means)

Claims (2)

The vehicle is equipped with a power generation motor capable of converting the power of an engine into electric power and motoring the engine, and a battery charged by the power generated by the power generation motor, and the power generation motor is activated during power running. A motor control device for use in a vehicle further equipped with a drive motor that converts generated electric power or electric power of the battery into motive power for driving the vehicle, and converts the motive power of the vehicle into electric power through regenerative operation. ,
A motor that executes motoring of the engine by the power generation motor when a value representing the state of charge of the battery exceeds a motoring start value set within a range between an upper limit value and a lower limit value. ring execution means;
motoring start value setting means for detecting a factor that increases a value representing the state of charge of the battery and variably setting the motoring start value according to the factor;
The motoring execution means causes the power generation motor to motor the engine when a value representing the state of charge of the battery exceeds the motoring start value regardless of the operating status of the drive motor. Execute, motor control device. The motor control device according to claim 1, wherein the factor is at least one of an altitude at which the vehicle is located, a gradient of the road surface on which the vehicle is traveling, or regenerative power generated by regenerative operation of the drive motor. .

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