JPH07231509A - Power generation controller for electric automobile - Google Patents

Abstract

PURPOSE:To prevent resonance with a component mounted on a vehicle by lowering the output power from a generator when the resonance frequency of vehicle mounted component is between the current r.p.m. and a target r.p.m. of an engine. CONSTITUTION:A motor 11 drives a wheel 18 through a reduction gear 12. The motor 11 is driven with an AC voltage obtained by frequency converting the voltage tram a generator 17 or a battery 14 through an inverter 13. the generator 17 is driven by an engine 15 through a speed increasing gear 16. the inverter 13, the engine 15 and the generator 17 are controlled by an ECU 19. If the resonance frequency of a vehicle mounted component is between the current r.p.m. and a target r.p.m. of the engine at the time of altering the r.p.m. of engine, output power from the generator 17 is lowered over a predetermined range of engine r.p.m. including the resonance frequency thus preventing resonance of vehicle mounted component due to the load of generator.

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 a device for controlling a power 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 been drawing attention from the viewpoint of environmental problems and the like. In addition to a type in which a motor is driven by electric power supplied from a battery to drive the electric vehicle, a type in which not only a battery but also a generator is mounted is known. This is generally called SHV (series hybrid vehicle), and the generator is usually driven by an engine.

Since this type of electric vehicle has a battery as a power supply source in addition to a generator, this battery functions as a buffer, so to speak, regardless of fluctuations in the running load of the vehicle (changes in vehicle speed, etc.) The engine can be operated at a constant speed so that the emission is optimized. That is, when the generator output (voltage) is less than the power required for traveling, the shortage is compensated by the power supplied from the battery, while when the generator output is more than the required power, the battery is charged with excess power. Therefore, the operating state of the engine can be made constant.

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 / hour, 30
~ 70 km / hour, divided into three ranges of 70 km / hour or more, and corresponding to each of these ranges, the amount of power generation is L (low), M
(Medium) and H (high) are set, and the engine speed is set to low, medium, and high. For example, when the vehicle speed is in the range of 30 to 70 km / hour, the power generation amount is M
(= Constant value), and while maintaining the engine speed at a middle value (= constant value), it means that the variation of the load due to the vehicle speed is supplemented or absorbed by the battery.

By the way, various components mounted on a vehicle (for example, steering, floor, seat, etc.) have their own resonance frequencies (resonance points). Therefore, when the engine speeds of the three stages described above match the resonance points of the components, the components resonate according to the vibration of the engine, which causes a problem such as impairing traveling comfort.

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

[0007]

However, in the transitional period when changing the engine speed, the engine speed and the component resonance frequency may coincide with each other, and the component vibration may increase. That is, for example, if 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 correspondingly changed from low to medium and the power generation amount is changed from L to M. Need to increase. The field current I
_f is a current for giving a field to the generator.

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

The vibration of the engine in this case includes the intrinsic vibration (vibration caused only by the rotation of the engine) resulting from the movement of the piston and the crank, and the vibration due to the combustion pressure of the engine (power generation by applying a field current). Vibration from the load). Of these, 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 a power generation load vibration that always occurs as long as power is generated, and cannot be canceled.

The present invention has been made in order to solve the above problems, and an electric vehicle capable of effectively preventing resonance of vehicle-mounted components due to engine rotation even in a transition period when the engine speed is changed. The purpose is to obtain a power generation control device.

[0011]

As described above, the engine vibration during the transition period of the engine speed change includes the intrinsic vibration (vibration caused only by the rotation of the engine) due to the motion of the piston and the crank. , Vibration due to the combustion pressure of the engine (vibration from the power generation load by giving a field current). The present invention pays attention to this fact and minimizes the power generation load in the transient period of the engine speed, and the battery is used to supply power during this period.

That is, a power generation control device for an electric vehicle according to a first aspect of the present invention includes a motor for driving a vehicle, a battery for supplying driving power to the motor, and a power supply for the motor. An electric vehicle equipped with a generator for charging the battery and an engine for driving the generator and performing stepwise control of the power generation output of the generator according to the operating conditions of the vehicle, which is mounted on a 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, and the result of the comparison. , When the resonance frequency is between the current engine speed and the target engine speed, the engine is generated within a predetermined engine 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, there is provided the power generation control device for an electric vehicle according to the first aspect, wherein the generator output control means reduces the power generation output by making the field current applied to the generator zero. It is characterized by that.

According to a third aspect of the present invention, in the power generation control device for an electric vehicle according to the first aspect, the battery is provided while the output of the generator is reduced within the range of engine speed including the resonance frequency. It is characterized in that the motor is driven by the electric power supplied from.

[0015]

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

According to the second aspect of the invention, the power generation output can be reduced by making the field current applied to the generator zero.

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

[0018]

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the overall structure of an SHV type electric vehicle in one embodiment of the present invention. This electric vehicle is equipped with a motor 11 that drives wheels 18 via a speed reducer 12. This motor 11 is a generator 1
7 or is driven by an AC voltage supplied from a battery 14 and frequency-converted by an 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 construction of the ECU 19 in FIG. 1 and the relationship between the ECU 19 and the generator 17 and engine 15 in more detail.

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

The output of the throttle opening correction unit 26 is supplied to the throttle opening adjuster 23, whereby the engine 1
The throttle opening of 5 is controlled. Further, the output of the field current determining unit 29 is supplied to the field current regulator 24, whereby duty control (on / off control) of the field current of the generator 17 is performed. Further, the memory 30 stores the resonance frequencies of various vehicle-mounted components (steering, floor, seat, etc.).

FIG. 3 shows changes with time of the engine speed N of the engine 15, the power output P of the generator 17, and the field current I _f .

As shown in this figure, when the vehicle speed V increases in the steady operation state (constant power generation amount), for example, when the vehicle speed shifts to another vehicle speed region in FIG. 6, the required power generation amount P also increases. In this case, the power generation amount is not increased immediately, but the power generation amount is increased over a time period of, for example, 10 seconds, and control is performed so that the battery 14 covers the required power increase during this period. In this respect, the present embodiment is similar to the conventional example.

However, this embodiment is characterized by how to increase the amount of power generation. That is, instead of monotonically increasing the amount of power generation as in the conventional case (FIG. 8), control that minimizes the amount of power generation in the engine speed region including the resonance point of the vehicle-mounted component (eg steering). I do. Specifically, the field current is set to 0 in the region of ± x before and after the resonance frequency N _ST to minimize the amount of power generation during this period. As a result, when the engine speed passes the resonance point of the steering wheel, it is possible to suppress the resonance of the steering wheel, which transiently occurs due to the power generation load.

Hereinafter, the method of controlling the power generation amount will be described in more detail with reference to FIGS. 4 and 5.

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 engine rotation (for example, every few milliseconds).

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

Next, the engine speed determination unit 28 determines the target engine 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) in which the target power generation amount P _T and the target engine speed N _T are associated with each other is referred to.

Next, the throttle opening degree calculation unit 25 calculates the basic throttle opening degree S ₀ based on the target power generation P _T and engine water temperature determined by the power generation amount determination unit 27 (step S103). In this case, for example, a function table (not shown) in which the target power generation amount P _T and the engine water temperature are associated with the basic throttle opening S ₀ is referred to.

The target engine speed N _T obtained here is
If it is not equal to the target engine speed N _T0 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 proceeds to step S105.

When the target engine speed N _T of this time does not change from the previous time, the actual engine speed obtained from the engine speed detector 22 is within a predetermined allowable range (± ΔN) with respect to the target value P _T. ) 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 if the upper limit value (N _T + ΔN) or more (step S10).
5; Y, step S106; Y), and the field current _If is turned on (step S108) to adjust the engine speed N _e .

On the other hand, when the engine speed N _e detected by the engine speed detector 22 is within the allowable range with respect to the target value N _T (step S105; Y, step S10).
6; N), and proceeds 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 is within a predetermined allowable range (± ΔP) with respect to the target value P _T. Specifically, when the detected power generation amount P is less than or equal to the lower limit value ( _PT- ΔP) of the allowable range (step S109; N), the throttle opening correction amount ΔS is incremented (step S112), Upper limit (P _T + Δ
P) or more (step S109; Y, step S110; Y), decrement ΔS (step S1
13) If it is within the allowable range (step S109;
Y, step S110; N), and ΔS are set to 0 (step S111). Then, this 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).

In this way, 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 within the above-mentioned allowable range. The values (N _T , S, P _T ) obtained in this cycle are variables (N _T0 , S ₀₀ ,
P _T0 ).

If the vehicle is accelerated and the vehicle speed V increases to another vehicle speed range (FIG. 6) in such a steady operation state, the target power generation amount P obtained in step S101 is obtained.
_T also increases. Therefore, the target engine speed N _T of this cycle does not match the target engine speed N _T0 of the previous cycle (step S104; N).

In this case, first, it is checked whether the engine speed is in the ascending direction or the descending direction, and if it is in the ascending direction (step S201; Y in FIG. 5), the resonance frequency N _{ST of the} steering wheel is set to the current engine speed. It is checked whether or not it exists between the number N _e and the target engine speed N _T , that is, whether or not the steering resonance frequency N _ST is passed during the increase of the engine speed (step S202). As a result, if it does not pass (step S202; N), the process proceeds to step S206.

On the other hand, when passing through the resonance point (step S202; Y), the target power generation amount is set to the minimum value P _M (step S203) and the target engine speed is set to (N _ST -x). (Step S204). That is, the provisional target points for the amount of power generation and the engine speed are set to B
Points and F points (Fig. 3). Note that P _M is the generator 17
Field current is power generation amount by the action of the magnetic field of the permanent magnet when the I _f to 0, the P _M = 0 if forming a field only field current without combination permanent magnet . And
The target throttle opening S _-x is calculated by the throttle opening calculator 25 (step S205), and the throttle opening is gradually controlled 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, the required transition time from (A point, E point) to (B point, F point) is set to 5 seconds, and this period is divided every 0.5 seconds. Therefore, during this period, the transition is made in 10 steps while setting the target value for each step.

Displacement amount (α, engine speed, power generation amount, and throttle opening degree at each stage (0.5 seconds)
[beta], [gamma]) is obtained by the following equations (1) to (3) when the routine first passes (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 the engine speed, the power generation amount, and the throttle opening degree at the start of the transition, respectively.
S _-x is when the engine speed reaches point F (ie,
(When N = N _ST −x).

The displacement amounts (α, β, γ) every 0.5 seconds thus obtained are retained in the previous cycle (N _T0 , S ₀₀ ,
P _T0 ), respectively (steps S209 to S21)
1), and the addition result is used as the next target value (N _T , S ₀ , P _T ).
And Then, while the target power generation amount P _T does not reach P _M (step S112; N), step S105 in FIG.
Through S116, control is performed so as to maintain the target value at each stage.

In this way, when the power generation amount and the engine speed approach the points B and F, respectively, by the stepwise control every 0.5 seconds, and the power generation amount P reaches the tentative target value PM (step S212). ; Y), throttle opening calculation unit 25
Calculates the throttle opening S _{+ x} such that the power generation amount and the engine speed are at the C point and the H point, respectively (step S2
13) and outputs it to the throttle opening adjuster 23 (step S214). As a result, the engine speed shifts from point F to point H under almost no load, and as shown by the broken line in FIG. 9, the resonance of the steering wheel when passing through resonance point G can be suppressed. .

Then, the engine speed N _e is (N _ST +
x) or more (step S216), the target points of the power generation amount and the engine speed are set to points D and I, respectively. That is, the target power generation amount is set to the original P ₂ (step S217), the target engine speed is set to the original N ₂ (step S218), and the basic throttle opening S ₂ is calculated based on this (step S218). 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
Similar to the above case, the target value is set for each predetermined time. Again, for example, from (C point, H point) to (D point, I
If the transition required time up to the point) is set to 5 seconds and the interval is divided into 0.5 seconds, the transition is performed in 10 steps while setting a target value for each step.

In this case, the engine rotation speed, the power generation amount, and the throttle opening displacement amounts (α, β, γ) at each stage (0.5 seconds) are calculated when the routine first passes through this routine. Step S206; Y), which is obtained 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 the H point (that is, when N = N _ST + x).

The displacement amount (α, β, γ) obtained every 0.5 seconds in this way is retained in the previous cycle (N _T0 ,
S ₀₀ and P _T0 ) respectively (steps S209 to S209)
211), and the addition result is used as the next target value (N _T , S ₀ , P
_T ). Then, until the target power generation amount P _T reaches P ₂ , that is, the target engine speed N _T becomes equal to the target engine speed N _{T0 of the} previous cycle (step S1
04; Y), and control is performed so as to maintain the target value at each stage by steps S105 to S116 of FIG.

In this way, 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 reach the original target values P _2. , N ₂ is reached, a steady operation state is entered thereafter, and that state is maintained by steps S105 to S116.

In the above description, the case where the engine speed increases due to the acceleration of the vehicle has been described, but the same applies to the case where the engine speed decreases due to the deceleration of the vehicle. As shown in FIG. By reducing the field current _If to 0 in the region including the resonance point of 1 to minimize the power generation load, it is possible to prevent steering resonance during the transient period of the engine speed.

In this embodiment, the resonance point of the steering wheel is explained as an on-vehicle component, but the resonance of these components can be prevented by performing similar transient control on other components (floor, seat, etc.). You can

Further, in the present embodiment, the transition time of each transient control is set to 5 seconds, but the present invention is not limited to this, and other values may be used. Further, although the interval of each stage is set to 0.5 seconds, other values may be used.

[0052]

As described above, according to the first aspect of the invention, when the engine speed is changed, the resonance frequency of the vehicle-mounted 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 invention, since the field output applied to the generator is set to zero to reduce the power generation output, there is an effect that the object can be achieved by relatively simple control.

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

[Brief description of drawings]

FIG. 1 is a block diagram showing 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 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 amount control by an ECU.

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

FIG. 6 is an engine speed N, a power generation amount P, and a field current I _f.
FIG. 4 is an explanatory view showing a temporal change of (when the engine speed is decreased).

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

FIG. 8 shows an engine speed N in the conventional power generation amount control,
It is explanatory drawing which shows the time change of the electric power generation amount P and the field current _If (when the engine speed increases).

FIG. 9 is a diagram showing a resonance state of an in-vehicle component during a transition period of engine speed.

[Explanation of symbols]

 11 Motor 13 Inverter 14 Battery 15 Engine 17 Generator 19 ECU 21 Power Generation Detector 22 Engine Rotation Speed Detector 23 Throttle Opening Adjuster 24 Field Current Adjuster 25 Throttle Opening Calculation Unit 26 Throttle Opening Correction Unit 27 Power Generation Quantity determining unit 28 Engine speed determining unit 29 Field current determining unit

Claims (3)

[Claims] 1. A motor for driving and driving a vehicle, a battery for supplying drive power to the motor, a generator for supplying power to the motor or charging the battery, and the generator. In an electric vehicle that includes an engine that drives the engine, and that performs a stepwise control of the power generation output of the generator according to the operating conditions of the vehicle, a storage unit that stores the resonance frequency of the vehicle-mounted device and a change in the engine speed. And 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 the current engine speed and the target engine speed. And a generator output control unit that controls 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 for an electric vehicle according to claim 1, wherein the generator output control means reduces the power generation output by reducing the field current applied to the generator to zero. apparatus. 3. The motor according to claim 1, wherein the motor is driven by the electric power supplied from the battery while the output of the generator is decreasing within the range of the engine speed including the resonance frequency. Electric vehicle power generation control device.