JP3092452B2 - Power generation control method for series hybrid vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a power generation output in a series hybrid vehicle (SHV).

[0002]

2. Description of the Related Art As an example of an electric vehicle (EV),
Hybrid vehicle equipped with an engine in addition to the motor (H
V) are known. Among the HVs, a configuration in which a generator is driven by an engine and a motor is driven by a power generation output of the generator and a discharge output of a battery is called SHV. The SHV has the advantage that the engine can be operated with low fuel consumption and low emission because the mechanical output of the engine is not connected to the drive shaft of the vehicle, and the normal EV because the motor can be driven by the power output of the generator. This has the advantage that the size of the battery can be reduced and the frequency of charging with external power can be suppressed.

[0003] Power output of the generator in the SHV exclusively, for the purpose of cover the driving power of the motor is controlled according to the drive power required from the motors. That is, since it is the generator and the battery that can generate the driving power of the motor, by controlling the power generation output of the generator according to the driving power required from the motor, the motor can be driven only by the generator. It can cover the driving power. It is known that the life of a battery (eg, a lead battery) can be extended by managing the state of charge (SOC) within a predetermined range. Since the fluctuation of the SOC of the battery can be suppressed by supplying the driving power of the motor only with the generator, the life of the battery can be extended by the above-described control.

However, simply controlling the power generation output in accordance with the motor drive power causes a large fluctuation in the power generation output as the vehicle travels, and the fluctuation in the power generation output = load fluctuation causes the engine speed to fluctuate. Fluctuations in engine speed lead to poor fuel economy and emissions. Therefore, usually, when controlling the power generation output according to the motor drive power,
The control having hysteresis regarding the SOC and the voltage of the battery is executed. That is, the threshold value for starting the reduction control of the power generation output and the threshold value for starting the increase control are set to different values, and the power generation output is not changed in an intermediate region separated by the two threshold values. Execute control. In this way, it is possible to prevent the engine speed from fluctuating excessively, which leads to deterioration of fuel efficiency and emission.

[0005]

However, there are cases where fluctuations in the engine speed cannot be sufficiently suppressed only by performing such control. For example, battery SO
When C and the voltage have relatively high values, the above-described control executes control in the direction of decreasing the power generation output and, consequently, the engine speed. However, if the driving power required by the motor at that time is large and the battery is discharging, the SOC and voltage of the battery will eventually decrease with this discharging, and thus control to reduce the power generation output will take a short time. I have to stop it. This leads to frequent fluctuations in the engine speed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has been made in consideration of whether a battery is being charged or discharged, thereby achieving an engine control. It is an object of the present invention to further suppress fluctuations in the number of revolutions and realize SHV with better fuel efficiency and emission. Also, the present invention relates to a battery SOC
Is controlled within a predetermined range to prevent shortening of the life due to overcharging or the like.

[0007]

In order to achieve the above object, a first power generation control method of the present invention provides a method for controlling power generation when a battery is being charged and its SOC is equal to or more than a first predetermined value. Reducing the power output of the generator; and if the battery is charging and its SOC is less than a first predetermined value and if the battery is discharging and its SOC is greater than a second predetermined value, Maintaining the power output of the generator at a previous value, and increasing the power output of the generator when the battery is discharging and its SOC is less than or equal to a second predetermined value, The first predetermined value is larger than the second predetermined value.

[0008] A second power generation control method according to the present invention includes a step of reducing the power generation output of the generator when the battery is being charged and the voltage is equal to or higher than a first predetermined value; The battery is discharging and the voltage is less than a second predetermined value.
Maintaining the power generation output of the generator at a previous value if it is above a predetermined value; and increasing the power generation output of the generator if the battery is discharging and its voltage is less than or equal to a second predetermined value. Causing the first predetermined value to be equal to the second
It is characterized by being larger than a predetermined value.

The present invention further determines the amount of decrease or increase in the output of the generator based on the SOC and voltage of the battery, the output of the generator, and the regenerative power of the motor when decreasing or increasing the output of the generator. The power generation output is reduced or increased by the determined power generation output decrease or increase amount.

The present invention is characterized in that the method has a step of reducing the amount of power generation output decrease or increase to a third predetermined value when the determined amount of power generation output decrease or increase exceeds a third predetermined value.

The present invention determines the amount of regenerative power reduction based on the SOC and voltage of the battery, the power generation output of the generator, and the regenerative power of the motor when reducing the amount of power generation output reduction to a third predetermined value during charging. Then, the regenerative power is reduced by the determined regenerative power reduction amount.

[0012]

According to the first power generation control method of the present invention, the control content is switched according to whether the battery is being charged or discharged in addition to the SOC of the battery. First, when the battery is being charged and its SOC is equal to or higher than the first predetermined value, the power generation output of the generator is controlled to decrease in principle. The battery is discharging and its SO
When C is equal to or smaller than a second predetermined value (first predetermined value> second predetermined value), the power generation output of the generator is controlled to increase. Otherwise, the power output of the generator is maintained at its previous value. As described above, if the SOC is discharging even when the SOC is equal to or more than the first predetermined value, the power generation output is maintained assuming that the SOC will soon decrease, and if the SOC is charging even if the SOC is equal to or less than the second predetermined value, the SOC will be shortly reached. The power generation output is maintained assuming that the engine speed is restored, so that the increase / decrease control of the power generation output and, consequently, the frequency of fluctuations in the engine speed are suppressed, and the fuel efficiency and emissions are improved.

[0013] In a second power generation control method of the present invention,
The voltage of the battery is used for switching the control instead of the SOC in the first power generation control method. Therefore, the same operation as in the first method occurs in this method. When both the SOC and the battery voltage are used for switching the control, in addition, the SOC of the battery is well controlled to a target range, and the shortening of the life due to overcharging or the like is prevented.

Further, in the present invention, when the power generation output of the generator is decreased or increased, the power generation output is based on the SOC and voltage of the battery, the power generation output of the generator and the regenerative power of the motor (that is, the charge / discharge balance of the battery). A decrease or increase is determined. Therefore, it is possible to optimally set the power generation output decrease amount or the increase amount, and to control the SOC of the battery to a better value.

In the present invention, when the determined power generation output decrease or increase exceeds the third predetermined value, the power generation output is controlled to be reduced by the third predetermined value. Therefore, the fluctuation amount of the engine speed is further suppressed, and better fuel economy and emission are realized.

If the power generation output decrease amount is limited to the third predetermined value during charging, the SOC and the voltage of the battery become insufficient. In order to compensate for this, in the present invention, when reducing the power generation output by the third predetermined value, the amount of regenerative power reduction is determined based on the SOC of the battery, the voltage, and the charge / discharge balance of the battery, and the determined amount of regenerative power reduction is determined. Only the regenerative power is reduced. As a result, the SOC and the voltage of the battery are kept at a sufficient level, so that the SOC of the battery is better controlled within a predetermined range and the shortening of the life due to overcharging or the like is prevented.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

(1) System Configuration FIG. 1 shows a system configuration according to an embodiment of the present invention. The system shown in FIG. 1 is an SHV, and has a configuration in which an AC motor 14 for driving a vehicle is driven by a discharge output of a battery 10 and a power generation output Wgen of a generator 12. More specifically, the discharge output of the battery 10 is supplied to an inverter 18 via a junction box 16 provided for controlling a power supply path. The generator 12 includes an engine 22 whose speed has been increased by the speed increaser 20.
The power output Wgen is supplied to the inverter 18 via the junction box 16 in the same manner as the discharge output of the battery 10. The inverter 18 converts the discharge output of the battery 10 and the output Wgen of the generator 12 into AC power, and supplies the AC power to the motor 14 as drive power Wm. Also, the motor 14
When the vehicle is regeneratively braked, the regenerative power Wreg from the motor 14 is converted into DC power by the inverter 18, and is connected to the battery 10 via the junction box 16.
Is supplied as charging power.

Therefore, in the vehicle shown in FIG.
Is being charged or discharged, whether the power output Wgen of the generator 12 or the drive power Wm of the motor 14 is
And the regenerative power Wreg from the motor 14. That is, between the three

When Wm ≦ Wreg + Wgen holds, the battery 10 is being charged,

## EQU2 ## If Wm> Wreg + Wgen holds, it can be considered that the battery 10 is discharging. When the charge by the external charger is ignored, the charge power of the battery

## EQU3 ## Wchg = (Wreg + Wgen) -Wm In the following description, this amount Wchg, which indicates that charging is being performed when the sign is positive and discharging when the sign is negative, is referred to as charge / discharge balance.

In this embodiment, as the control ECU, an EV ECU 24 for controlling the entire vehicle and an engine 2
2, a power generation ECU 28 that controls the generator 12, and a battery E that manages the battery 10.
A CU 30 and a regenerative ECU 32 that controls a hydraulic braking mechanism and issues a regenerative torque command are mounted.

When the vehicle operator operates the key switch,
In response to this, the EV ECU 24 supplies a closing signal to the junction box 16 to mutually connect the battery 10, the generator 12, and the inverter 18. The EV ECU 24
After receiving the start confirmation signal of the inverter 18 and the like, the rotation speed Nm of the motor 14, the voltage and current of each part detected in the junction box 16, the SOC of the battery 10 and the battery upper limit voltage VBMAX detected by the battery ECU 30, Inverter 18 temperature, inverter 18 overheating, overcurrent, junction box 18
The following operation is performed while monitoring the leakage of electricity in the system.

First, when the vehicle operator depresses the accelerator pedal 34, the EV ECU 24 sets the accelerator pedal 3
The torque to be output from the motor 14 is determined based on the amount of depression of step 4. This torque is called a torque command Tm. The EVECU 24 detects the rotational speed Nm of the motor 14 and limits the upper limit of the torque command Tm based on the detected rotational speed Nm. The EVECU 24 generates a current command indicating a current vector to be supplied to the motor 10 based on the torque command Tm, performs a process such as coordinate conversion based on the detected rotation speed Nm of the motor 14, and converts the current into an inverter 18.
To supply. In the inverter 18, a switching signal such as a PWM (pulse width modulation) signal is generated based on the current command, and each switching element included in the inverter 18 switches according to the switching signal. As a result, the current obtained from the inverter 18 becomes a current corresponding to the current command, and the output torque of the motor 14 becomes a value corresponding to the torque command Tm.

When the vehicle operator depresses the brake pedal 36, for example, the brake switch 38 is turned on, and the hydraulic pressure appears in the brake master cylinder 40. When the brake switch 38 is turned on, the regenerative ECU 32 detects the oil pressure of the brake master cylinder 40 with the M / C sensor 42. The regenerative ECU 32 is a battery ECU
The hydraulic pressure of the brake master cylinder 40 is determined by referring to the SOC of the battery 10 and the battery upper limit voltage VBMAX detected by the battery 30, the voltage VB and the current IB of the battery 10 detected at the junction box 16, and the vehicle speed given by the EV ECU 24. The corresponding braking torque is generated by the total oil pressure and regeneration. That is, the regenerative ECU 32 first distributes a braking torque corresponding to the hydraulic pressure of the brake master cylinder 40 to the hydraulic pressure and the regeneration so that, for example, the braking force distribution with the regenerative priority is realized. Regenerative ECU
A drive signal 32 is supplied to a linear valve 48 provided on a hydraulic transmission path from a brake master cylinder 40 to a disc brake caliper 46 via a proportioning and bypass (P & B) valve 44, and is detected by the M / C sensor 42. The hydraulic braking force is controlled such that the difference between the hydraulic pressure and the hydraulic pressure detected by the W / C sensor 50 provided on the disc brake caliper 46 side becomes a value corresponding to the distribution to the regenerative side. Thereby, the hydraulic pressure acting on the brake rotor 52 becomes a hydraulic pressure corresponding to the distribution to the hydraulic pressure side. At the same time, the regenerative ECU 32 gives the EV ECU 24 the distribution to the regenerative as a regenerative torque command. EVE
The CU 24 controls the inverter 18 so that the regenerative torque command is realized. Inverter 1
8 is notified to the regenerative ECU 32 in the next cycle.

Engine ECU 26 and power generation ECU 28
Controls the engine 22 and the generator 12, respectively, during these operations. First, the engine ECU 26 calculates the number of revolutions Ne of the engine 22 as power generation E
While informing the CU 28 as needed, the engine 22 is operated in a fully open throttle state (WOT) so that the emission and fuel efficiency are optimized. However, in the region where the engine speed Ne is low, the throttle opening θth is changed to power generation E in order to secure efficiency.
While notifying the CU 28 at any time, the throttle opening θ of the engine 22 according to the throttle command from the power generation ECU 28
Control th. The power generation ECU 28 determines whether the SO
C, the voltage VB, the current IB, the voltage Vgen and the current Igen of the generator 12, the rotation speed Ne of the engine 22, the throttle opening θth, the regenerative torque Treg, the rotation speed Nm of the motor 14, the torque command Tm, and the like. A generator torque command for controlling the output of the generator 12 is generated based on. Further, the power generation ECU 28 provides a regeneration inhibition signal and a regeneration reduction amount to the regeneration ECU 32 under predetermined conditions. Regenerative ECU 32
Stops the regenerative operation in response to the regeneration prohibition signal, and changes the regenerative torque command to a smaller value in accordance with the regeneration decrease amount.

(2) Operation of Power Generation ECU FIG. 2 shows a flow of the operation of the power generation ECU 28. The operation shown in this figure is a flow of operation after the engine 22 is started and enters a steady operation state.

After executing a predetermined initialization process (100), the power generation ECU 28 inputs various information necessary for control (102). The input is the voltage Vgen of the generator 12
And the current Igen, the rotation speed Ne of the engine 22 and the throttle opening θth, the regenerative torque (return value) Treg actually output, the voltage VB and the current IB of the battery 10, the rotation speed Nm of the motor 14 and the torque (torque command). Tm, etc. The power generation ECU 28 uses the input information, for example, Nm, Tm, Treg, Vgen, and Igen, to generate the driving power Wm of the motor 14 and the regenerative power Wre from the motor 14.
g and the power output Wgen of the generator 12 are calculated (10
4, 106, 108). In that case, the following equation can be used. Here, ηm, ηreg and ηgen are the powering, regenerative and power generation efficiencies, respectively. In this equation, Wm
Although the torque command Tm is used in the calculation of (1), if a reliable torque sensor can be used, an actual measured value of the powering torque may be used. Further, the motor current and the voltage may be detected and the product thereof may be calculated.

[0027]

Wm = Nm · Tm · ηm Wreg = Nm · Treg · ηreg Wgen = Vgen · Igen · ηgen The power generation ECU 28 is based on Wm, Wreg and Wgen.
Whether the charge / discharge balance (energy balance) Wchg of the battery 10 is positive or negative is determined (110). The control operation of the power generation ECU 28 is during charging (Wchg ≧ 0), that is, Wm ≦ Wreg + W
When it is determined that the current is gen, the operation shifts to the operation shown in FIG.
When it is determined that Wreg + Wgen, the operation shifts to the operation shown in FIG.

First, in FIG. 3A, the battery 1
The control of the field of the generator 12 and the control of the rotation speed Ne of the engine 22 are switched depending on whether the voltage VB and the SOC of 0 are respectively equal to or higher than X1 or Y1. Here, X1 is set to, for example, the upper limit voltage VBMAX of the battery 10 or a value close to the upper limit voltage, and Y1 is set to the SOC upper limit value at which the acceptability (ability to receive charging power) of the battery 10 extremely deteriorates or a value close to the SOC upper limit value. Is done. When the voltage VB of the battery 10 is equal to or higher than X1 and when the SOC
Is greater than or equal to Y1, according to FIG.
, The field current of the generator 12 is reduced. Conversely, when the voltage VB of the battery 10 is not higher than X1 and the SOC is not higher than Y1, the field current of the generator 12 and, consequently, the rotation speed Ne of the engine 22 are maintained.

Conversely, in FIG. 3B, the battery 1
The control of the field control of the generator 12 and the control of the rotation speed Ne of the engine 22 are switched depending on whether the voltage VB and the SOC of 0 are equal to or less than X2 or Y2, respectively. Here, X2 is set to, for example, the lower limit value of the voltage VB of the normally operable battery 10 or a value close thereto.
Is set to, for example, the lower limit value of SOC that allows normal traveling or a value close to this. When the voltage VB of the battery 10 is equal to or lower than X2 and when the SOC is equal to or lower than Y2, according to this figure, the field current of the generator 12 is increased so that the rotation speed Ne of the engine 22 increases. Conversely, the battery 10
Is not less than X2 and the SOC is not less than Y2, the field current of generator 12 and hence engine 22
Is maintained.

Switching the control contents in accordance with the sign of the charge / discharge balance Wchg as described above is performed while the battery 10 is managed and controlled within a target range while the rotation speed Ne of the engine 22 is controlled.
This makes it possible to suppress fluctuations in the fuel consumption and thereby prevent deterioration of emissions and fuel consumption. For example, in the area shown in FIG. 4, the battery 10 is discharging and VB exceeds even X1. In this case, VB
Is high, but is still discharging, so if left as it is, VB will eventually decrease. Thus, in the present embodiment, the fluctuation of the rotation speed Ne is suppressed by maintaining the field current instead of reducing the field current and lowering the rotation speed Ne of the engine 22 as in the related art. Conversely, in the region shown in FIG. 4, battery 10 is being charged and SO
C is lower than X2. In this case, although the SOC is certainly low but being charged, if the battery is left as it is, the SOC will eventually increase. Therefore, in this embodiment, in this case, instead of increasing the field current and increasing the rotation speed Ne of the engine 22 as in the related art, the field current is maintained and the fluctuation of the rotation speed Ne is suppressed. . By performing control in consideration of the sign of the charge / discharge balance Wchg in this manner, fluctuations in the rotation speed Ne of the engine 22 can be suppressed as compared with the related art.

In the flow of FIG. 2, the control operation shown in FIG.
The control operation shown in (b) is executed according to the flow after step 114. In step 112, it is determined whether VB≥X1 or SOC≥Y1 holds. In step 114, VB≤X2 or S
It is determined whether or not OC ≦ Y2 holds.

If it is determined in step 112 that none of the conditions are satisfied (the white background in FIG. 3A), or if it is determined that none of the conditions is satisfied in step 114 (see FIG. In the white part (b)), the power generation ECU 28 controls the rotation speed decrease amount Ne1 and the rotation speed increase amount ΔN in order to maintain the rotation speed Ne of the engine 22.
e2 is set to 0 (116). Power generation ECU 28
Is the set rotation speed decrease amount ΔNe1 and the rotation speed increase amount ΔN
The generator torque command is calculated and determined according to e2 (11
8). In this case, since ΔNe1 and ΔNe2 are both 0, the power generation ECU 28 maintains the generator torque command at the previous value. After executing the predetermined fail-safe process (120), the power generation ECU 28 outputs the generator torque command to the generator 12 (122). The generator torque command is a command related to the output of the generator 12, that is, a command related to the field current. In step 122, this command is supplied to the generator 12 as a field current. When such control is performed, the power output Wgen of the generator 12 and the rotation speed Ne of the engine 22 are maintained at the previous values. If the operating range of the engine 22 at that time is a range in which the efficiency of the engine 22 is maximized when it deviates from the constant throttle line, the throttle command is also calculated and determined in step 118, and This command is output to the engine ECU 26.

If it is determined in step 112 that any of the conditions is satisfied (the hatched portion in FIG. 3A), the power generation ECU 28 calculates the rotational speed reduction amount ΔNe1 (124). This calculation is based on VB, SOC and Wchg
Perform based on. In step 118 executed later, the generator torque command and the like are reduced in accordance with the rotation speed decrease amount ΔNe1.
Is reduced by the rotation speed reduction amount ΔNe1. By doing so, the rotation speed Ne of the engine 22 is not unnecessarily greatly reduced, and the effect of preventing the deterioration of the emission and the fuel consumption is further increased.

The power generation ECU 28 determines whether or not the rotation speed reduction amount ΔNe1 exceeds a predetermined upper limit value α1 (12).
6). If the rotation speed decrease amount ΔNe1 does not exceed the upper limit value α1, the operation of the power generation ECU 28 jumps to step 132.
e1 is limited to α1 (128). The reason for such a limitation is that if the large ΔNe1 is used as it is in step 118, the rotational speed Ne of the engine 22 will fluctuate greatly. By imposing an upper limit on the rotational speed decrease amount ΔNe1, in the present embodiment, it is possible to prevent the rotational speed Ne of the engine 22 from greatly fluctuating in the situation shown in FIG.

On the other hand, if the upper limit is imposed on the rotational speed decrease amount ΔNe1, the discharge of the battery 10 becomes difficult to progress because the power output Wgen of the generator 12 does not decrease so much. Therefore,
In this embodiment, the amount of decrease (the amount of decrease in regeneration) of the regenerative power Wreg is calculated in the subsequent step 130. This operation is also performed by V
B, SOC and Wchg. The calculated regenerative reduction amount is output to the regenerative ECU 32 in step 122, and the regenerative ECU 32 reduces the regenerative torque command accordingly. In this case, the regenerative power Wreg decreases, so that the charge / discharge balance Wchg of the battery 10 fluctuates more than discharge. As a result, the SOC of the battery 10 is controlled within a target range. Regenerative ECU 32
Simultaneously supplies a drive signal to the linear valve 48 to compensate for a decrease in braking force due to a decrease in regeneration.

After the rotational speed decrease amount ΔNe1 is thus determined, the power generation ECU 28 performs a lower limit determination on the rotational speed of the engine 22 after execution of step 122 (1).
32). That is, a value obtained by subtracting ΔNe1 from the current rotational speed Ne (the rotational speed of the engine 22 after execution of step 122).
When Ne-ΔNe1 is less than the predetermined lower limit β1, the power generation ECU 28 limits ΔNe1 to Ne−β1 (134),
Otherwise, the process proceeds to step 118. ΔNe1
Is limited to Ne-β1, Ne-ΔNe1 becomes β1. If the generator torque command is calculated based on this in later step 118, the rotation speed Ne of the engine 22 after execution of step 122 becomes β1. In this way,
The lowering of the rotation speed Ne of the engine 22 is limited by the lower limit value β1. At this time, in order to advance the discharge of the battery 10, the power generation ECU 28 generates a regeneration prohibition signal for prohibiting regeneration (136), and outputs this to the regeneration ECU 32 in step 122. The regenerative ECU 32
In response, the regenerative torque command is set to 0, and the linear valve 48 is fully opened to cover the required braking force with the hydraulic braking force.

If it is determined in step 114 that any of the conditions is satisfied (the hatched portion in FIG. 3B), the power generation ECU 28 calculates the rotation speed increase ΔNe2 (138). This calculation is based on VB, SOC and Wchg
Perform based on. In step 118 executed later, the generator torque command is increased in accordance with this rotation speed increase amount ΔNe2, and by executing step 122, the rotation speed Ne of the engine 22 is increased by the rotation speed increase amount ΔNe2. By doing so, the rotational speed Ne of the engine 22 is not unnecessarily increased, and the effect of preventing the deterioration of the emission and the fuel consumption is further enhanced.

The power generation ECU 28 determines whether or not the rotation speed increment ΔNe2 exceeds a predetermined upper limit α2 (14).
0). If the rotation speed increase ΔNe2 does not exceed the upper limit value α2, the operation of the power generation ECU 28 jumps to step 144.
e2 is limited to α2 (142). The reason for such a limitation is that if the large ΔNe2 is used as it is in step 118, the rotational speed Ne of the engine 22 will fluctuate greatly. In this case, unlike during charging, there is no need to limit the regenerative power Wreg.

After the rotation speed increase amount ΔNe2 is determined in this way, the power generation ECU 28 performs an upper limit determination on the rotation speed of the engine 22 after execution of step 122 (1).
44). That is, a value obtained by adding ΔNe2 to the current rotational speed Ne (the rotational speed of the engine 22 after execution of step 122) N
If e + ΔNe2 exceeds a predetermined upper limit β2, the power generation EC
U28 limits .DELTA.Ne2 to .beta.2-Ne (146), otherwise the process moves to step 118. ΔNe2 is β
If restricted to 2-Ne, Ne + ΔNe2 becomes β2.
If the generator torque command is calculated based on this in the subsequent step 118, the rotation speed Ne of the engine 22 after the execution of the step 122 becomes β2. In this manner, the increase in the rotation speed Ne of the engine 22 is limited by the upper limit value β2. In this case, there is no need to prohibit regeneration.

Therefore, according to the present embodiment, the battery 10
While appropriately controlling the SOC of the engine 2 within a predetermined range.
2, the fluctuation of the rotation speed Ne can be suppressed, and deterioration of emission and fuel efficiency can be prevented. Note that X1, X
It is preferable that the values of 2, Y1, Y2, etc. be determined according to the characteristics of the battery 10. Further, by changing these values sequentially according to the charge / discharge balance Wchg, it is possible to realize more adaptive control.

[0041]

As described above, according to the power generation control method of the present invention, the control content is switched according to whether the battery is being charged or discharged, in addition to the SOC and voltage of the battery. Therefore, when the battery is being discharged even when the SOC or the battery voltage is high, or when the battery is being charged even when the SOC or the battery voltage is low, there is no variation in the power generation output and, consequently, the engine speed. And emission will be better. Further, when both the SOC and the battery voltage are used for switching the control, the SOC of the battery can be controlled better, and the shortening of the life due to overcharging or the like can be prevented.

Further, according to the present invention, when decreasing or increasing the power generation output of the generator, the amount of power generation output reduction or increase is determined based on the battery SOC, voltage and battery charge / discharge balance. Optimum setting of the power generation output decrease amount or increase amount is possible, and the SOC of the battery can be controlled to a better value.

According to the present invention, when the determined power generation output decrease or increase exceeds the third predetermined value, the power generation output is reduced by the third predetermined value, so that the engine speed fluctuation amount is further suppressed. And better fuel economy and emission can be realized.

According to the present invention, the shortage of the SOC and the voltage of the battery caused by limiting the amount of decrease in the power generation output to the third predetermined value is determined based on the SOC of the battery, the voltage, and the charge / discharge balance of the battery. Since the regenerative power reduction control based on the determined regenerative power reduction amount compensates, the SOC of the battery can be better controlled, and the shortening of the life due to overcharging or the like can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration of a series hybrid vehicle according to one embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of an operation of a power generation ECU in the embodiment.

FIG. 3 is a diagram showing a characteristic operation of the embodiment;
3A is a diagram illustrating an operation during charging, and FIG. 3B is a diagram illustrating an operation during discharging.

FIG. 4 is a timing chart showing the effect of this embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Battery 12 Generator 14 Motor 18 Inverter 22 Engine 24 EV ECU 26 Engine ECU 28 Power generation ECU 30 Battery ECU 32 Regenerative ECU Vgen Generator voltage Igen Generator current Ne Engine speed VB Battery voltage IB Battery current SOC battery Nm Motor rotation speed Tm Motor torque (torque command) Treg Regenerative torque Wgen Generator output Wreg Motor regenerative power Wm Motor drive power X1, X2 Battery voltage discrimination threshold Y1, Y2 Battery SOC determination threshold ΔNe1 Revolution decrease ΔNe2 Revolution increase α1, α2 Revolution decrease and increase upper limit β1, β2 Lower and upper limit of engine revolution

Continuation of the front page (51) Int.Cl. ⁷ identification code FI H02P 9/04 B60K 9/00 E (56) References JP-A-5-316658 (JP, A) (58) Fields investigated (Int.Cl. . ^7, DB name) B60L 11/00 - 11/14 B60K 6/02 B60L 7/14 B60L 11/18 F02D 29/06 H02P 9/04

Claims (5)

(57) [Claims] 1. A engine, a generator driven by the engine, running in the rechargeable battery and driven by the power output and battery discharge output of the generator series hybrid vehicle equipped with a motor for supplying regenerated electric power in the battery it is, when the battery is is being charged and its charging state is equal to or more than the first predetermined value, and the step of reducing the power output of the generator, the battery is being charged and its charging state is lower than the first predetermined value And if the battery is discharging and the state of charge is greater than a second predetermined value, maintaining the power output of the generator at a previous value; and Increasing the power generation output of the generator when is less than or equal to a second predetermined value, wherein the first predetermined value is larger than the second predetermined value. Power generation control method of a series hybrid vehicle and features. Wherein the engine, a generator driven by the engine, running in the rechargeable battery and driven by the power output and battery discharge output of the generator series hybrid vehicle equipped with a motor for supplying regenerated electric power in the battery is, when the battery is is being charged and its voltage is equal to or more than the first predetermined value, and the step of reducing the power output of the generator, the battery is being charged and its voltage is less than the first predetermined value Maintaining the power output of the generator at a previous value when the battery is discharging and the voltage is above a second predetermined value; and when the battery is discharging and the voltage is at a second predetermined value. if the value or less, has a step of increasing the power output of the generator, a series of first predetermined value being greater than the second predetermined value Power generation control method for hybrid vehicles . 3. The series hybrid according to claim 1, wherein
In the power generation control method for electric vehicles, when decreasing or increasing the power output of the generator, the amount of reduction or increase in the power output is determined based on the state of charge and voltage of the battery, the power output of the generator, and the regenerative power of the motor. A series hybrid vehicle, wherein the power generation output is reduced or increased by the determined power generation output decrease or increase amount.
Power generation control method of. 4. A series hybrid vehicle according to claim 3.
The power generation control method for a series of determined power output decrease or increase the amount when exceeding a third predetermined value, characterized by having a step of decreasing a small decrease power output or increase until the third predetermined value
Power generation control method for hybrid vehicles . 5. A series hybrid vehicle according to claim 4.
In the power generation control method of the above, when reducing the generated power reduction amount to a third predetermined value during charging, the regenerative power reduction amount is determined based on the state of charge and voltage of the battery, the power generation output of the generator and the regenerative power of the motor, A power generation control method for a series hybrid vehicle, characterized in that regenerative power is reduced by the determined amount of regenerative power reduction.