JP2002369592A - Controller of generator for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller of generator for vehicles, in which power generation efficiency can be enhanced at light load, while preventing complication of the arrangement. SOLUTION: An electric load 2 for vehicle and a power storage means 1 are supplied with power from a generator 3. A controller 8 controls intermittent power generation of the generator 3, such that the average output power of the generator 3 is substantially equal to the power consumption of the electric load 2 for vehicle. Since the operating point of the generator can be shifted to the high output power side at power generation, efficiency of the generator can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicular generator. The present invention is applied to a vehicle equipped with a power storage means and a generator.

[0002]

2. Description of the Related Art In recent years, it has been required to improve fuel efficiency of vehicles from the viewpoint of environment such as CO2 reduction. The regenerative system that can be stored in is attracting attention. Conventional vehicle generators include electric loads (ECUs, headlights, blowers, wipers, AV equipment,
In order to be able to supply the power consumed in a navigation system, the maximum output is 1.0-1.
Generally, it was set to about 7 kW. However, the generator used in the regenerative system requires a larger output (e.g.
About 10 kW). The average power consumption of the electric load depends on the usage of each load, but it is 10-15
When the vehicle is traveling, it is about 0.2 kW.

[0003]

The applicant has found that the maximum output power of the generator is much larger than the average power consumption of the electric load at normal times, and the difference becomes even greater in the regenerative braking type generator. . As a result, it has been found that in most cases, the generator is operated at a small output operating point where the power generation efficiency is low, resulting in a problem that the average power loss increases and the fuel economy is disadvantageous.

More specifically, the loss of the generator includes a fixed loss irrelevant to its output power and a loss having a positive correlation with a change in output power. The fixed loss is large, and the efficiency is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a control device for a vehicular generator capable of improving the power generation efficiency under a small load while suppressing the complexity of the device configuration. , Its purpose.

[0006]

According to a first aspect of the present invention, there is provided a control device for a vehicle generator for supplying electric power to a vehicle electric load, and supplying electric power to the electric storage device and the vehicle electric load. A generator, and a power generation controller configured to adjust output power of the generator, wherein the power generation controller controls the power generation so that an average output power of the generator is substantially equal to a power consumption of the electric load for the vehicle. It is characterized by having an intermittent power generation mode for intermittent power generation of the machine.

With this configuration, even if the power consumption of the electric load for the vehicle is small, the generator is operated intermittently, the electric power is supplied from the electric storage means to the electric load for the vehicle when the electric power generation is stopped, and the electric storage means is charged when the electric power is generated. By supplying power to the vehicle electrical load, the operating point of the generator at the time of power generation is shifted to the high output power side, thereby improving the efficiency of the generator.

[0008] Since the power storage means is used, the loss is a factor in reducing the efficiency. However, if the intermittent power generation mode is used when the improvement in the generator efficiency exceeds the increase in the power storage means loss, the total energy efficiency is reduced. Can be improved.

According to a second aspect of the present invention, the control device for a vehicle generator according to the first aspect further includes a rotation speed detecting means for detecting a rotation speed of the generator, and the power generation control unit stores the rotation speed in advance. On the basis of the relationship between the number of revolutions of the generator, the power generation efficiency, and the output power, the output power having good power generation efficiency at the current rotation speed is intermittently generated by the generator.

Since the relationship between the power generation efficiency of the generator and the output power changes according to the rotation speed, the generator is operated with the output power at which the power generation efficiency is good (for example, the highest) according to the detected rotation speed. By doing so, the generator can always generate power in the highest or good condition regardless of the power consumption of the electric load for the vehicle or the fluctuation of the rotation speed.

According to a third aspect of the present invention, in the control apparatus for a vehicle generator according to the first aspect, the power generation control section continuously outputs the output power substantially equal to the power consumption of the electric load for the vehicle to the generator. A continuous power generation mode in which the energy-efficient mode is selected from the two modes. According to this configuration, the intermittent power generation mode is performed only when the intermittent power generation mode has higher energy efficiency (total efficiency) than the continuous power generation mode, so that power generation can be performed with the highest possible efficiency.

According to a fourth aspect of the present invention, in the control device for a vehicle generator according to the third aspect, the power generation control unit further comprises:
Since the energy efficiency is estimated based on the power generation efficiency of the generator and the charge / discharge efficiency of the power storage means, it is possible to improve the energy efficiency in consideration of the loss in charge / discharge of the power storage means.

According to a fifth aspect of the present invention, in the control apparatus for a vehicle generator according to any one of the first to fourth aspects, the power generation control unit may further include a maximum output power capable of outputting the generator during vehicle deceleration. It is characterized in that the generator is caused to generate power and the generator is generated intermittently when the vehicle is not decelerated. According to this configuration, an improvement in energy efficiency can be realized without restricting regenerative braking.

According to a sixth aspect of the present invention, in the control device for a vehicle generator according to any one of the first to fifth aspects, the power generation control unit further includes a power generation control unit configured to generate the power of the generator when the vehicle acceleration exceeds a predetermined value. Is characterized by stopping. According to this configuration, the generator is stopped at the time of large acceleration, so that the acceleration is improved. At this time, the power storage means is in charge of supplying power to the vehicle electric load, but after the generator returns to power generation, the power storage means is charged again.

According to a seventh aspect of the present invention, the control device for a vehicle generator according to any one of the first to sixth aspects further comprises means for detecting the SOC or voltage of the power storage means, and Commanding the generator to generate power at a predetermined output until the SOC or voltage of the power storage means rises to a first predetermined value, and after the SOC or voltage of the power storage means reaches the first predetermined value, It is characterized by comprising a control for stopping the power generation of the power generator until the power generation decreases to a second predetermined value.

That is, according to this configuration, the generator is stopped between the two values of the state of charge of the power storage means, so that intermittent power generation can be easily performed. Alternatively, the voltage may be used for the power generation stop determination and the SOC may be used for the power generation start determination, or vice versa.

According to an eighth aspect of the present invention, in the vehicle generator control device according to any one of the first to seventh aspects, the power storage means further comprises a lithium battery. Since the lithium battery has a small charge / discharge loss, energy efficiency can be improved.

According to a ninth aspect of the present invention, in the vehicle generator control device according to any one of the first to sixth aspects, the power storage means further comprises an electric double layer capacitor.
Since the electric double layer capacitor has a small charge / discharge loss, energy efficiency can be improved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the control apparatus for a vehicle generator according to the present invention will be described in detail with reference to the following embodiments.

(Configuration) FIG. 1 shows a circuit configuration according to the first embodiment of the present invention.

An assembled battery 1 formed by connecting a plurality of lithium batteries in series supplies power to an electric load 2. The generator 3 supplies power to the electric load 2 and charges the battery pack 1. The generator 3 has an armature winding 4, a three-phase full-wave rectifier 5, a field winding 6, a field current control switch 7, a flywheel diode FD, and the like. The controller 8 controls the generator 3. A signal line 11 from the current sensor 9 for detecting the current of the battery pack 1, a signal line 12 for detecting the voltage of the battery pack 1, and a signal line 13 from the temperature sensor 10 in the battery pack 1
Are connected to the controller 8. Further, although not shown, a signal line 14 from a vehicle speed sensor and a signal line 15 from a generator speed sensor are connected.
The controller 8 intermittently controls the field current control switch 7 through the field current control signal line 16.

(Operation) FIG. 2 shows an example of the relationship between the rotation speed of the generator 3 and the maximum output. When energy is regenerated during vehicle deceleration, power is generated at an output substantially equal to the maximum output according to the rotation speed. However, except during deceleration,
The output required for the generator is significantly smaller than during regeneration. Conventionally, since the power consumed by the electric load 2 is generated in real time, for example, the electric power consumption of the electric load 2 is about 0.2 kW, and the generator rotation speed is about 4000 rpm.
In the case of m, the operating point of the generator is P1 in the figure, and it has been necessary to generate power with a very small output (about 7%) with respect to the maximum output point Pmax at this rotation speed.

FIG. 3 shows an example of the relationship between the output of the generator 3 and the power generation efficiency.

When 0.2 kW is output at 4000 rpm (point A), the power generation efficiency is about 20 times higher than at 1.0 kW output (point B) where the power generation efficiency is the highest at the same rotational speed.
%, Which hindered improvement in fuel efficiency.

Therefore, in this embodiment, the power generation is performed intermittently at the operating point (point B) where the power generation efficiency is high, and the average power generation is made substantially equal to the power consumption of the electric load 2, thereby achieving high efficiency. Operation is possible. FIG. 4 shows the generator output, the input / output power of the Li battery, and the power consumption of the electric load during the intermittent operation. If the time is t (min), T
During the period of 1 ≦ t <T2, the generator has a high efficiency of 1.0 k
Electric power is generated at an output of W, and 0.2 kW of the power is supplied to an electric load, and the remaining 0.8 kW is charged to a Li battery. Then T
During the period of 2 ≦ t <T3, the generator stops generating power and Li
A battery supplies 0.2 kW to the electrical load. Similar operations are repeated after T3. The ratio of the time during which the generator is operating and the time during which the generator is stopped is (T2-T1) / (T3-T1
) = 1/5, so that the generator outputs, on average, power that is substantially equal to the power consumption of the electric load. However, if the output of the generator suddenly changes, the generator torque suddenly changes and gives a sense of incongruity to the driver. Therefore, in practice, the output of the generator is gradually changed to such an extent that it does not cause discomfort.

In the case of the intermittent operation as shown in FIG. 4, the generated energy is temporarily stored in the battery and then supplied to the electric load. Becomes possible. When the energy generated by the generator 3 is temporarily stored in the battery and then supplied to the load 2, if the power consumption of the electric load is equal to or less than a predetermined value due to the loss due to charging and discharging of the battery 1, the power may be intermittent. When the operation is higher in total energy efficiency, and when it exceeds a predetermined value, the operation is not intermittent and is operated in real time with an output corresponding to the load power consumption, and the total energy efficiency is higher.

This will be described in detail below. When operating with an output corresponding to the load power consumption in real time, power is supplied directly from the generator to the electric load, so there is no loss due to battery charging and discharging, and the total energy efficiency E1 is E1 = ηG (PL , N) [%]. Here, PL is the power consumption (W) at the electric load,
η G (p, N) is the power generation efficiency of the generator, and is a function of the output p and the generator speed N. An example of ηG (p, N) is as shown in FIG. On the other hand, in the case of intermittent operation at a predetermined output Pconst with good efficiency, energy is temporarily stored in the battery, so that a loss due to charging and discharging of the battery occurs, and the total energy efficiency E2 is given by: ｝ · ΗG (Pconst, N) + (Pconst−PL) / Pconst · ｛ηG (Pconst,
N) / 100｝ · ｛ηbat1 (Pconst−PL) / 10
0｝ · {ηbat2 (PL) / 100} × 100 [%]. Where ηbat1 (P) is the charging efficiency (%), ηbat2
(P) is the discharge efficiency (%) of the battery, which is a function of each charge power and charge power. The charging efficiency and discharging efficiency change depending on the internal resistance of the battery. FIG. 5 shows an example in which the internal resistance of the battery pack 1 is 100 mΩ. Comparing E1 and E2, the most efficient operation is possible if E1 ≧ E2, if the output is operated in real time according to the load power consumption, and if E1 <E2, the operation is intermittent. .

The internal resistance of the battery pack is 100 mΩ, Pconst
FIG. 6 shows an example of comparing E1 and E2 under the condition of = 1.0 kW. Power consumption PL of electric load is about 0.8kW
If it is smaller than E1, then E1.gtoreq.E2, so that it is operated in real time with an output corresponding to the load power consumption, and PL is about 0.3.
If it is smaller than 8 kW, E1 <E2, so that control for intermittent operation is performed.

Next, a method for efficiently regenerating the deceleration energy and performing the above-described high-efficiency operation control of the generator will be described. In a state where the generator is driven by rotating the engine while consuming fuel, the energy efficiency of the vehicle is increased by performing the above-described high-efficiency operation control. On the other hand, when the generator is driven by the energy transmitted from the wheels at the time of deceleration, operating the generator at the maximum output can regenerate more energy, thereby improving fuel efficiency. Therefore, in the present invention, the vehicle is found to be in a decelerating state from the vehicle speed sensor and the stroke of the brake pedal, etc., at the time of deceleration, the generator generates power at maximum output,
Except during power generation, high-efficiency operation control by intermittent operation as described above is performed.

It is clear that the above-described control can be easily performed by the controller 8, so that further description will be omitted.

When performing high-efficiency operation control by intermittent operation other than during deceleration, the state of charge of the battery (SOC: Stat)
e of Charge) and the ON / OFF of the generator can be controlled based on the acceleration of the vehicle. A specific control method will be described with reference to FIG. Step0
The SOC of the battery at 1 is a first predetermined value (SOC-1)
If the value is smaller, the Charge flag is set to 1 (Step 02); otherwise, the Char flag is set.
The ge flag is set to 0 (Step 03).

Next, in Step 04, it is determined whether or not the vehicle is in a decelerating state.
At 05, the generator generates power at maximum output. If the vehicle is not in a deceleration state, the acceleration of the vehicle is increased to a predetermined value (acc.
[M / s2]) or more, and if it is not less than a predetermined value, power generation is stopped in Step 07;
At step 08, it is determined whether or not the Charge flag is 1. If the Charge flag is 1, Step 0 is further performed.
In step 9, the SOC of the battery is compared with a first predetermined value (SOC-1). If the SOC is smaller, in step 10, the generator performs power generation at an output with high efficiency according to the rotation speed. Stops power generation in Step 11, and
To set the Charge flag to 0. Also, Ste
At p08, it is determined whether or not the Charge flag is 1, and 1
If not, the SOC of the battery is compared with a second predetermined value (SOC-2) in Step 13;
Power generation is stopped at 14, otherwise, Step 15
Then, the generator performs power generation with an output that becomes highly efficient in accordance with the number of revolutions, and sets the Charge flag to 1 in Step 16. Here, the first predetermined value (SOC-1) is set to be larger than the second predetermined value (SOC-2). For example, SOC-1 = 60%, SOC-2 = 50%
Set as follows. The predetermined value (acc) for judging the acceleration state is set to, for example, acc = 0.5 [m / s2].

FIG. 8 shows an example of changes over time in vehicle speed, acceleration, battery SOC, and generator output when this control is performed. The time is t, and the Charge flag is t =
Details will be described on the assumption that it is 1 in T1.

During the period of T1 ≦ t <T2, the vehicle speed is 40 k
m / h constant, acceleration 0 [m / s2], Charge
When the flag is 1, the SOC is a first predetermined value (SOC-1 = 6
0%), the output (1.0 kW) at which the generator becomes highly efficient according to the rotation speed by Step 10 in FIG.
To generate electricity. Since the power consumption of the electric load is about 0.2 kW, 0.2 kW of the generated 1.0 kW is supplied to the electric load, and the remaining 0.8 kW is charged into the Li battery.
SOC increases.

During the period of T2 ≦ t <T3, the vehicle
Accelerating from 80 m / h to 80 km / h with an acceleration of 0.56
[M / s2] and a predetermined acceleration (acc = 0.5 [m
/ S2]) or more, the generator stops power generation in Step 07. 0.2kW from Li battery to electric load
Is supplied, and the SOC decreases.

During the period of T2 ≦ t <T4, the vehicle
m / h constant, acceleration 0 [m / s2], Charge
When the flag is 1, the SOC is a first predetermined value (SOC-1 = 6
0%), the generator generates power with an output (1.0 kW) that becomes highly efficient in accordance with the rotation speed in Step 10. 0.2 kW of the generated 1.0 kW is supplied to an electric load, and the remaining 0.8 kW is charged into a Li battery,
SOC increases.

At t = T4, the SOC reaches the first predetermined value (SOC-1 = 60%), the generator stops generating power in Step 11, and changes to Charg in Step 12.
Set the e flag to 0.

During the period of T4 <t <T5, the vehicle
m / h constant, acceleration 0 [m / s2], Charge
When the flag is 0, the SOC is a second predetermined value (SOC-2 = 5).
0%), the generator stops generating power in Step 14. 0.2 kW is supplied from the Li battery to the electric load, and the SOC is reduced.

At t = T5, the SOC reaches the second predetermined value (SOC-2 = 50%), the generator stops generating power in Step 15, and changes to Charg in Step 16.
Set the e flag to 1.

Similarly, during the period of T5 <t <T9, SO
When C increases and reaches a first predetermined value (SOC-1 = 60%), power generation is stopped, and then when SOC decreases and reaches a second predetermined value (SOC-2 = 50%), power generation is performed. Is repeated.

During the period of T9 <t <T10, the vehicle
The vehicle is decelerating from m / h to 0 km / h, and in Step 05, the generator generates power at the maximum output according to the rotation speed. 0.2 kW of the generated power is supplied to the electric load, and the remaining is charged to the Li battery, and the SOC increases.

In the period of T10 <t <T11, the vehicle is 0 km
/ H, the acceleration is 0 [m / s2], Cha
The rge flag is 0, and the SOC is a second predetermined value (SOC-
2 = 50%), the generator stops generating power in Step 14.

During the period of T11 <t <T12, the vehicle
Accelerating from 70 m / h to 70 km / h with an acceleration of 0.97
[M / s2] and a predetermined acceleration (acc = 0.5 [m
/ S2]) or more, the generator stops power generation in Step 07.

At t = T12, the SOC reaches the first predetermined value (SOC-1 = 60%), the generator stops generating power in Step 11, and changes to Charg in Step 12.
Set the e flag to 0.

During the period of T12 <t <T13, the vehicle
m / h constant, acceleration 0 [m / s2], Charge
When the flag is 0, the SOC is a second predetermined value (SOC-2 = 5).
0%), the generator stops generating power in Step 14.

In the above control, ON / OFF of the generator is controlled based on the SOC of the battery. However, based on the voltage of the battery, when the voltage reaches a first predetermined value (for example, 39.0 V), the power generation is stopped. The control may be performed such that the power generation is stopped and then the power generation is restarted when the SOC reaches a second predetermined value (for example, 35.0 V).

(Effects) (1) Even when the power consumption of the electric load is small, high-efficiency power generation is possible, and fuel efficiency can be improved. (2) By using a Li battery or an electric double layer capacitor having high charge / discharge efficiency, energy loss is reduced and fuel efficiency is improved. (3) The generator operation method is optimized so that the energy efficiency is maximized according to the power consumption of the electric load in consideration of the loss due to charging and discharging of the Li battery and the electric double layer capacitor. Efficient operation control can be performed more effectively. (4) ON / OFF of generator based on battery SOC or voltage
By performing the OFF control, the generator starts generating power after using up the regenerated energy (except during deceleration).
No power is wasted and fuel efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a control device for a vehicle generator according to the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a rotation speed of a generator and a maximum output.

FIG. 3 is a characteristic diagram showing a relationship between an output of a generator and a power generation efficiency.

FIG. 4 is a timing chart showing a temporal change in power of each unit.

FIG. 5 is a characteristic diagram showing a relationship between charge / discharge power and efficiency of a battery.

FIG. 6 is a characteristic diagram showing a relationship between power consumption of an electric load and total energy efficiency.

FIG. 7 is a flowchart showing a power generation control operation.

8 is a timing chart showing changes over time in vehicle speed, acceleration, battery SOC, and generator output when the control operation shown in FIG. 7 is performed.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 battery pack (power storage means) 2 vehicle electric load 3 generator 8 controller (power generation control unit) 15 rotation speed detector

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G060 AA05 CA02 DA01 DB01 DB07 5H590 AA02 CA07 CA23 CC01 CD01 CE05 DD23 DD64 EA05 EA13 FA06 FC12 FC17 GA02 HA02 HA06 HB02

Claims (9)

[Claims] An electric power storage means for supplying electric power to an electric load for a vehicle, a generator for supplying electric power to the electric power storage means and the electric load for a vehicle, and a power generation control unit for adjusting output power of the electric generator; The power generation control unit has an intermittent power generation mode for intermittently generating the generator so that the average output power of the generator is substantially equal to the power consumption of the electric load for the vehicle. Generator control device. 2. The control device for a vehicular generator according to claim 1, further comprising: a rotation speed detecting unit configured to detect a rotation speed of the generator, wherein the power generation control unit stores the rotation speed of the generator in advance. A control device for a vehicular generator, wherein the generator intermittently generates output power having good power generation efficiency at a current rotational speed based on a relationship between power generation efficiency and output power. 3. The control device for a vehicle generator according to claim 1, wherein the power generation control unit has a continuous power generation mode in which the generator continuously generates output power substantially equal to power consumption of the electric load for the vehicle. A control device for a vehicular generator, wherein one of the two modes is selected which is superior in energy efficiency. 4. The control device for a vehicle generator according to claim 3, wherein the power generation control unit estimates the energy efficiency based on a power generation efficiency of the generator and a charge / discharge efficiency of the power storage unit. A control device for a vehicle generator. 5. The control device for a vehicle generator according to claim 1, wherein the power generation control unit causes the generator to generate power at a maximum output power capable of outputting the generator when the vehicle is decelerated. A control device for a vehicular generator, wherein the generator intermittently generates power when the vehicle is not decelerated. 6. The control device for a vehicle generator according to claim 1, wherein the power generation control unit stops the power generation of the generator when the vehicle acceleration exceeds a predetermined value. Control device for a vehicle generator. 7. The control device for a vehicle generator according to claim 1, further comprising: means for detecting an SOC or a voltage of the power storage means, wherein the intermittent power generation mode is controlled by the power generation means. Instructs the generator to generate power at a predetermined output until the SOC or voltage rises to a first predetermined value. After the SOC or voltage of the power storage means reaches the first predetermined value, a second predetermined A control device for a vehicular generator, comprising a control for stopping the power generation of the generator until the value decreases to a value. 8. The control device for a vehicle generator according to claim 1, wherein said power storage means comprises a lithium battery. 9. The control device for a vehicle generator according to claim 1, wherein said power storage means comprises an electric double layer capacitor.