JP3178218B2 - Electric vehicle power generation control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle and, more particularly, to an apparatus for controlling the output of an electric vehicle equipped with a generator in addition to a battery.

[0002]

2. Description of the Related Art In recent years, electric vehicles have attracted attention from the viewpoint of environmental problems and the like. As the electric vehicle, a type in which a motor is driven by simply driving a motor with electric power supplied from a battery and a type in which a generator as well as a battery is mounted are known. This is commonly called an SHV (Series Hybrid Vehicle), and the generator is usually driven by an engine.

[0003] This type of electric vehicle has a battery as a power supply source in addition to the generator, so that it functions as a buffer, so to speak, regardless of fluctuations in the running load of the vehicle (such as a change in the vehicle speed), fuel efficiency and the like. The engine can be operated at a constant level so that the emission is optimized. That is, if the generator output (voltage) is less than the power required for traveling, the shortage is compensated for by the power supplied from the battery, while if the generator output is greater than the required power, the battery is charged with the excess power. Therefore, the operating state of the engine can be stabilized.

Now, consider the vehicle speed as the running load of the vehicle. As shown in FIG. 7, the vehicle speed is 0 to 30 km / h, 30
発 電 70 km / h, 70 km / h or more, and the power generation amount is set to L (low), M
(Medium) and H (high) are set, and the engine speed is set to low, medium and high. This means that, for example, when the vehicle speed is in the range of 30 to 70 km / h, the power generation amount is M
(= Constant value), while the engine speed is maintained at a medium value (= constant value), the amount of load fluctuation due to vehicle speed is supplemented or absorbed by the battery.

Incidentally, various components (for example, a steering wheel, a floor, a seat, etc.) mounted on a vehicle have their own resonance frequencies (resonance points). For this reason, when each of the above-mentioned three stages of engine speeds coincides with the resonance point of each component, the components resonate in response to the vibration of the engine, causing problems such as impairing running comfort.

Therefore, when designing the components or setting the engine speed in a steady state, care is taken so that the engine speed does not match the component resonance frequency.

[0007]

However, during the transition period when the engine speed is changed, the engine speed and the component resonance frequency may coincide with each other, and the vibration of the component may increase. That is, for example, when the vehicle speed is accelerated from a state of 20 km / hour to a state of 40 km / hour, as shown in FIG. 8, the engine speed is changed from low to medium in response to this, and the power generation amount is changed from L to M. Need to be increased. The field current I
_f is a current for giving a field to the generator.

In such a transitional period, for example, if the resonance point of the steering wheel is within the transient change range of the engine speed, the engine speed passes through the resonance point of the steering wheel as shown by a solid line in FIG. At that time, the steering temporarily picks up the vibration of the engine and vibrates greatly.

[0009] In this case, the vibration of the engine includes a vibration inherent in the piston and the crank (vibration caused only by rotation of the engine) and a vibration caused by the combustion pressure of the engine (power generation by applying a field current). Vibration from the load). Among them, the former vibration can be canceled in consideration of the balance at the design stage of each element of the engine, but the latter vibration is power generation load vibration that is inevitably generated as long as power is generated, and cannot be canceled.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an electric vehicle capable of effectively preventing resonance of components mounted on a vehicle due to engine rotation even in a transition period in which the engine speed is changed. An object is to obtain a power generation control device.

[0011]

As described above, the vibration of the engine in the transition period of the change of the engine speed includes the original vibration (vibration caused only by the rotation of the engine) caused by the movement of the piston and the crank. And vibration caused by the combustion pressure of the engine (vibration caused by a power generation load caused by applying a field current). The present invention pays attention to this fact, and reduces the power generation load during the transition period of the engine speed as much as possible, and the power supply during this period is covered by the battery.

That is, the electric power generation control device for an electric vehicle according to the present invention includes a motor for driving the vehicle, a battery for supplying a driving power to the motor, and a power supply for the motor. An electric vehicle that includes a generator for charging the battery and an engine that drives the generator, and that performs stepwise control of the power generation output of the generator according to operating conditions of the vehicle. Storage means for storing the resonance frequency of the device; comparison means for comparing the current engine speed and the target engine speed with the resonance frequency stored in the storage means when the engine speed is changed; When the resonance frequency exists between the current engine rotation speed and the target engine rotation speed, the start-up is performed within a predetermined engine rotation speed range including the resonance frequency. It is characterized in that it comprises a generator output control means for performing control to reduce the power output of the machine, the.

According to a second aspect of the present invention, in the electric power generation control apparatus for an electric vehicle according to the first aspect, the generator output control means reduces the generated output by setting a field current applied to the generator to zero. It is characterized by the following.

According to a third aspect of the present invention, in the power generation control device for an electric vehicle according to the first aspect, while the output of the generator is reduced within a range of an engine speed including the resonance frequency, the battery is not charged. The motor is driven by electric power supplied from the motor.

[0015]

According to the first aspect of the present invention, when the engine speed is changed, if the resonance frequency of the on-vehicle device is present between the current engine speed and the target engine speed, the resonance frequency is changed. The power generation output of the generator is reduced within a predetermined engine speed range including the range, and the resonance of the vehicle-mounted device due to the power generation load is prevented.

According to the second aspect of the present invention, the power generation output is reduced by setting the field current applied to the generator to zero.

According to the third aspect of the present invention, the motor is driven by the power supplied from the battery while the power generation output is reduced within the range of the engine speed including the resonance frequency.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the overall configuration of an SHV electric vehicle according to an embodiment of the present invention. This electric vehicle is provided with a motor 11 that drives wheels 18 via a speed reducer 12. The motor 11 is connected to the generator 1
7 or a battery 14 and is driven by an AC voltage whose frequency is converted by the inverter 13. The generator 17 is connected to the engine 15 via the gearbox 16.
Driven by Further, the inverter 13, the engine 15 and the generator 17 are controlled by an ECU (Electro Control Unit) 19.

FIG. 2 shows the internal structure of the ECU 19 in FIG. 1 and the relationship between the ECU 19, the generator 17, and the engine 15 in more detail.

As shown in this figure, the ECU 19 has a power generation amount determination unit 27 that determines the amount of power generation from the vehicle speed V and the remaining capacity (battery capacity) BT of the battery 14, and determines the engine speed from the determined amount of power generation. Engine speed determining section 28, throttle opening calculating section 25 for calculating the throttle opening from the determined engine speed and engine water temperature, and throttle opening based on the power generation amount of generator 17 obtained from power generation amount detector 21. The throttle opening correction unit 26 that corrects the degree, the determined engine speed, the power generation amount of the generator 17 obtained from the power generation amount detector 21, and the rotation of the engine 15 obtained from the engine speed detector 22 A field current determining unit 29 that determines the field current from the numbers is provided.

The output of the throttle opening correction unit 26 is supplied to a throttle opening adjuster 23, which allows the engine 1
The control of the throttle opening of No. 5 is performed. Further, the output of the field current determination unit 29 is supplied to the field current regulator 24, whereby the duty control (on / off control) of the field current of the generator 17 is performed. The memory 30 stores resonance frequencies of various components mounted on the vehicle (such as a steering wheel, a floor, and a seat).

FIG. 3 shows changes over time of the rotation speed N of the engine 15, the power output P of the generator 17, and the field current _If .

As shown in this figure, in a steady operation state (constant power generation amount), when the vehicle speed V increases, for example, when the vehicle shifts to another vehicle speed region in FIG. 6, the required power generation amount P also increases. In this case, instead of immediately increasing the power generation amount, the power generation amount is increased over a period of, for example, 10 seconds or more, and control is performed so that the required power increase during this time is covered by the battery 14. This point is the same as the conventional example in this embodiment.

However, the present embodiment is characterized by the way of increasing the amount of power generation. In other words, instead of monotonically increasing the power generation amount as in the related art (FIG. 8), the control is such that the power generation amount is minimized in the engine speed region including the resonance point of the vehicle-mounted component (for example, the steering). I do. Specifically, in the zero field current in the region of about ± x of the resonant frequency N _ST, to minimize this period of power generation. As a result, it is possible to suppress the resonance of the steering which occurs transiently due to the power generation load when the engine speed passes through the resonance point of the steering.

Hereinafter, such a method of controlling the power generation amount will be described in more detail with reference to FIGS.

The ECU 19 executes a series of step processes shown in FIGS. 4 and 5 in a predetermined time cycle. This cycle is performed, for example, every 30 ° CA (crank angle) of the engine rotation (for example, every several milliseconds).

In each cycle, the power generation amount determination unit 27 of the ECU 19 determines a target power generation amount P _T based on the remaining capacity BT of the battery 14 and the vehicle speed V obtained from a vehicle speed sensor (not shown).
Is obtained (step S101 in FIG. 4). This target power generation amount P
_T indicates, for example, the remaining capacity BT and the vehicle speed V as the target power generation amount P _T
This is performed by referring to a function table (not shown) associated with.

Next, the engine speed determination section 28 obtains a target engine rotational speed N _T based on the determined target power generation amount P _T (step S102). In this case, for example, a function table (not shown) that associates the target power generation amount _PT with the target engine speed _NT is referred to.

Next, the throttle opening calculator 25 calculates the basic throttle opening S ₀ based on the target power generation _PT determined by the power generation amount determiner 27 and the engine coolant temperature (step S103). In this case, for example, the target power generation amount P _T and the function table correlating engine water temperature to the basic throttle opening S ₀ (not shown) is referred to.

The target engine speed _NT obtained here is
If it is not equal to the target engine speed _NT0 obtained in the previous cycle (step S104; N), the process proceeds to step S201 in FIG. 5, and if it is equal (step S10).
4; Y), and proceed to step S105.

If the current target engine speed _NT is not different from the previous one, the actual engine speed obtained from the engine speed detector 22 is within a predetermined allowable range (± ΔN) with respect to the target value _PT . ) Is controlled. Specifically, when the detected engine speed N _e is less than the lower limit of the allowable range (N _T -ΔN) (step S105;
N), the field current _If is turned off (step S107), and when it is equal to or more than the upper limit value ( _NT + ΔN) (step S10).
5; Y, step S106; Y), by turning on the field current I _f (step S108), and adjusts the engine speed N _e.

On the other hand, if the engine speed N _e detected by the engine speed detector 22 is within an allowable range with respect to the target value N _T (step S105; Y, step S10
6; N), and proceed to step S109.

In steps S109 to S113, the throttle opening is controlled so that the power generation amount P detected by the power generation amount detector 21 falls within a predetermined allowable range (± ΔP) with respect to the target value _PT . Specifically, when the detected power generation amount P is equal to or smaller than the lower limit value of the allowable range (P _T −ΔP) (step S109; N), the correction amount ΔS of the throttle opening is incremented (step S112). Upper limit (P _T + Δ
P) or more (step S109; Y, step S110; Y), ΔS is decremented (step S1).
13) If it is within the allowable range (step S109;
Y, step S110; N), and ΔS is set to 0 (step S111). Then, the correction amount ΔS is added to the basic throttle opening S ₀ (step S114), and the addition result S is output to the throttle opening adjuster 23 (step S115).

As described above, by performing the duty control of the field current _If and the correction control of the throttle opening, the power generation amount P and the engine speed are controlled so as to be within the allowable ranges described above. Note that the values (N _T , S, P _T ) obtained in this cycle are variables (N _T0 , S ₀₀ ,
P _T0 ).

In this steady operation state, if the vehicle is accelerated and the vehicle speed V increases to another vehicle speed region (FIG. 6), the target power generation amount P obtained in step S101 is obtained.
_T also increases. Therefore, the target engine speed _NT of the current cycle does not match the target engine speed _NT0 of the previous cycle (step S104; N).

Firstly, in this case, the engine speed is checked whether upward or downward direction, when was increasing direction (Fig. 5 step S201; Y), further current engine rotational steering resonance frequency N _ST the number N _e and whether existing between the target engine speed N _T, i.e. examine whether passing through the steering of a resonance frequency N _ST midway increase in the rotational speed of the engine (step S202). As a result, if it does not pass (step S202; N), the process proceeds to step S206.

On the other hand, when it passes through the resonance point; set (step S202 Y), sets the target power generation amount to the minimum value P _M (step S203), the target engine rotational speed (N _ST -x) (Step S204). That is, the tentative target points of the power generation amount and the engine speed are respectively B
Point and point F (FIG. 3). In addition, P _M is the power generator 17
Is the amount of power generated by the action of the magnetic field of the permanent magnet when the field current _{If is set} to 0. When the field is formed only by the field current without using the permanent magnet, P _M = 0. . And
The throttle opening calculator 25 calculates the target throttle opening S- _x (step S205), and gradually controls the throttle opening so as to reach the points B and F. This control is performed by setting a target value for each predetermined time. Here, for example, it is assumed that the transition required time from (point A, point E) to (point B, point F) is 5 seconds, and the interval is divided every 0.5 seconds. Therefore, the process shifts in ten stages while setting the target value for each stage.

The engine speed, power generation amount, and throttle opening displacement (α,
β, γ) are obtained by the following equations (1) to (3) when this routine is first passed (step S206; Y).

Α = [(N _ST −x) −N ₁ ] / 10 (1) β = (P _M −P ₁ ) / 10 (2) γ = (S− _x− S ₁ ) / 10 (3) Here, N ₁ , P ₁ , and S ₁ are an engine speed, a power generation amount, and a throttle opening at the start of the transition, respectively.
S- _x is determined when the engine speed reaches point F (ie,
N = N _ST -x).

The displacement amounts (α, β, γ) obtained every 0.5 seconds obtained in this way are used as the held values (N _T0 , S ₀₀ ,
P _T0 ) (steps S209 to S21)
1), the next target value and the addition result _{(N T, S 0, P} T)
And Then, among the target power generation amount P _T does not reach the P _M (step S112; N), step S105 in FIG. 4
Through S116, control is performed so as to maintain the target value in each stage.

As described above, the power generation amount and the engine speed approach the points B and F, respectively, by the stepwise control every 0.5 seconds, and when the power generation amount P reaches the temporary target value PM (step S212). ; Y), throttle opening calculating section 25
Calculates the throttle opening S _{+ x} such that the power generation amount and the engine speed become the point C and the point H, respectively (step S2).
13), and outputs this to the throttle opening adjuster 23 (step S214). As a result, the engine speed shifts from the point F to the point H with almost no load, and the resonance of the steering when passing through the resonance point G can be suppressed as shown by the broken line in FIG. .

Then, the engine speed N _e becomes (N _ST +
x) or more (step S216), the target points of the power generation amount and the engine speed are set to point D and point I, respectively. That sets a target power generation amount to the original P ₂ (step S217), sets the target engine speed to the original N ₂ (step S218), calculates the basic throttle angle S ₂ based on this (step S21
9).

Then, the throttle opening is gradually controlled so as to reach the points D and I. The control in this case is also
The target value is set for each predetermined time in the same manner as described above. Again, for example, from (C point, H point) to (D point, I point)
Assuming that the required transition time up to point (5) is 5 seconds and the interval is divided into 0.5 seconds, the transition is made in 10 steps while setting the target value for each step.

In this case, the displacements (α, β, γ) of the engine speed, the power generation amount, and the throttle opening for each stage (0.5 second) are obtained when the routine first passes through this routine ( Step S206; Y), calculated by the following equations (4) to (6).

Α = [N ₂ − (N _ST + x)] / 10 (4) β = (P ₂ −P _M ) / 10 (5) γ = (S ₂ −S _{+ x} ) / 10 (6) Here, S _{+ x} is the throttle opening when the engine speed reaches point H (that is, when N = N _ST + x).

The displacement amounts (α, β, γ) obtained every 0.5 seconds obtained in this manner are used as the held values (N _T0 ,
S ₀₀ , P _T0 ) (steps S 209 to S 209).
211), the next target value and the addition result (N _T, S _0, P
_T ). Then, until the target power generation amount P _T reaches P _2, that is, until the target engine rotational speed N _T is equal to the target engine speed N _T0 of the previous cycle (step S1
04; Y), control is performed in steps S105 to S116 in FIG. 4 to maintain the target value in each stage.

As described above, the power generation amount and the engine speed approach the points D and I, respectively, by the stepwise control every 0.5 seconds, and the power generation amount and the engine speed respectively become the original target values P _2. reaches the N _2, thereafter becomes steady operation state, the state is maintained in step S105～S116.

In the above description, the case where the engine speed increases due to the acceleration of the vehicle has been described. The same applies to the case where the engine speed decreases due to the deceleration of the vehicle. As shown in FIG. By setting the field current _If to 0 and minimizing the power generation load in the region including the resonance point, it is possible to prevent the steering resonance in the transition period of the engine speed.

In this embodiment, the resonance point of the steering is described as the vehicle-mounted component. However, the same transient control is performed on other components (floor, seat, etc.) to prevent the resonance of these components. Can be.

In the present embodiment, the transition time of each transient control is set to 5 seconds. However, the present invention is not limited to this, and other values may be used. Further, although the interval between the steps is 0.5 seconds, another value may be used.

[0052]

As described above, according to the first aspect of the present invention, when the engine speed is changed, the resonance frequency of the on-vehicle device exists between the current engine speed and the target engine speed. In this case, since the power generation output of the generator is reduced within a predetermined engine speed range including the resonance frequency, it is possible to prevent the resonance of the vehicle-mounted device due to the power generation load in the transient state. .

According to the second aspect of the present invention, since the power generation output is reduced by setting the field current applied to the generator to zero, there is an effect that the object can be achieved by relatively simple control.

According to the third aspect of the present invention, the motor is driven by the power supplied from the battery while the power generation output is falling within the range of the engine speed including the resonance frequency. There is an effect that the speed of the vehicle can be maintained at a required level even during the period.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of an electric vehicle according to an embodiment of the present invention.

FIG. 2 is a detailed configuration of an ECU in FIG. 1 and the ECU;
FIG. 3 is a block diagram showing a connection relationship between the motor and an engine and a generator.

3 is an explanatory diagram showing the temporal change of the engine speed N, the power generation amount P and the field current I _f in the embodiment of the power generation control of the present invention (when the engine speed is increased).

FIG. 4 is a flowchart showing details of power generation control by an ECU.

FIG. 5 is a flowchart following FIG. 4 showing details of power generation control by the ECU.

FIG. 6 shows an engine speed N, a power generation amount P, and a field current _If.
FIG. 5 is an explanatory diagram showing a temporal change of the engine speed (when the engine speed is decreased).

FIG. 7 is a diagram illustrating a relationship between a vehicle speed, a power generation amount, and an engine speed.

FIG. 8 shows an engine speed N in a conventional power generation amount control;
FIG. 4 is an explanatory diagram showing a temporal change of a power generation amount P and a field current _If (when the engine speed increases).

FIG. 9 is a diagram illustrating a resonance state of the vehicle-mounted component during a transition period of the engine speed.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 motor 13 inverter 14 battery 15 engine 17 generator 19 ECU 21 power generation amount detector 22 engine speed detector 23 throttle opening regulator 24 field current regulator 25 throttle opening calculator 26 throttle opening corrector 27 power generation Amount determination unit 28 Engine speed determination unit 29 Field current determination unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60L ⁷ /00-13/00 B60K 6/02 F02D 29/06 H02P 9/04

Claims (3)

(57) [Claims] 1. A motor for driving and driving a vehicle, a battery for supplying driving power to the motor, a generator for supplying power to the motor or charging the battery, and the generator An engine for driving the vehicle, wherein the electric vehicle performs stepwise control of the power generation output of the generator according to the operating conditions of the vehicle. Comparing means for comparing the current engine speed and the target engine speed with the resonance frequency stored in the storage means; and as a result of the comparison, the resonance frequency is determined to be the current engine speed and the target engine speed. And generator output control means for performing control to reduce the power generation output of the generator in a range of a predetermined engine speed including the resonance frequency, Power generation control apparatus for an electric vehicle characterized by comprising. 2. The power generation control of an electric vehicle according to claim 1, wherein the generator output control means reduces the power generation output by reducing a field current applied to the generator to zero. apparatus. 3. The motor according to claim 1, wherein the motor is driven by the power supplied from the battery while the output of the generator is reduced within the range of the engine speed including the resonance frequency. Power generation control device for electric vehicles.