JP4632075B2 - Control device for vehicle generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for a vehicular generator. It is applied to an automobile equipped with a power storage means and a generator.
[0002]
[Prior art]
In recent years, there has been a demand for improved fuel efficiency of vehicles due to environmental aspects such as CO2 reduction, and a regenerative system that converts vehicle kinetic energy into electrical energy with a generator during deceleration and stores it in a battery, an electric double layer capacitor, or the like. Attention has been paid. A conventional generator for a vehicle has a maximum output of 1. to be able to supply electric power consumed by an electric load (ECU, headlight, blower, wiper, AV equipment, navigation system, etc.). Generally, it was set to about 0 to 1.7 kW. However, the generator used in the regeneration system needs to have a larger output (for example, about 3 to 10 kW) in order to recover the deceleration energy of the vehicle. The average power consumption of the electric load is about 0.2 kW when traveling in the 10-15 mode, although it depends on the usage state of each load.
[0003]
[Problems to be solved by the invention]
The present applicant has found that the maximum output power of the generator is much larger than the average power consumption during normal times of the electric load, and the difference becomes even more severe in the regenerative braking generator. As a result, it was found that the generator is operated at a small output operating point where the generation efficiency is low in most cases, resulting in a problem that the average power loss becomes large and the fuel consumption becomes disadvantageous.
[0004]
More specifically, the loss of the generator includes a fixed loss irrelevant to the output power and a loss having a positive correlation with the change in the output power, and is fixed compared to the output power at the small output operating point. The efficiency is reduced due to the large loss.
[0005]
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 at a small load while suppressing the complexity of the device configuration. It is said.
[0006]
[Means for Solving the Problems]
The control device for a vehicular generator according to claim 1, wherein the power storage means for supplying electric power to the electric load for the vehicle, the generator for supplying electric power to the electric storage means and the electric load for the vehicle, and the output of the generator A power generation control unit that adjusts the power, and the power generation control unit has an intermittent power generation mode in which the generator intermittently generates power so that an average output power of the generator is substantially equal to a power consumption of the electric load for the vehicle. A control device for a vehicular generator having rotation speed detection means for detecting the rotation speed of the generator, wherein the power generation control unit stores the rotation speed, power generation efficiency, and output power of the generator stored in advance; On the basis of the above relationship, output power having good power generation efficiency at the current rotational speed is intermittently generated by the generator .
[0007]
According to this configuration, even if the power consumption of the electric load for the vehicle is small, the generator is intermittently operated, 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 and charged for the electric power generation. By supplying power to the electric load, the operating point of the generator during power generation is shifted to the large output power side, thereby improving the efficiency of the generator.
[0008]
In addition, since the loss becomes an efficiency reduction factor because the power storage means is used, the total energy efficiency can be improved if this intermittent power generation mode is used when the improvement of the generator efficiency exceeds the loss increase of the power storage means. be able to.
[0010]
Since the relationship between the power generation efficiency of the generator and the output power changes according to the rotational speed, by operating the generator with the output power at which the power generation efficiency is good (for example, the highest) according to the detected rotational speed Regardless of the power consumption of the electric load for the vehicle or fluctuations in the rotational speed, the generator can always generate power in the highest or good state.
[0011]
3. The configuration according to claim 2 , wherein power storage means for supplying power to the vehicle electrical load, a generator for supplying power to the power storage means and the vehicle electrical load, and a power generation control unit for adjusting output power of the generator. The generator control unit has an intermittent power generation mode in which the generator intermittently generates power so that the average output power of the generator is substantially equal to the power consumption of the vehicle electrical load. In the apparatus, the power generation control unit has a continuous power generation mode in which the generator continuously generates output power substantially equal to the power consumption of the electric load for the vehicle, and is more energy efficient from the two modes. It is characterized by selection. According to this configuration, since the intermittent power generation mode is performed only when the intermittent power generation mode is superior in energy efficiency (total efficiency) to the continuous power generation mode, it is possible to generate power with the highest possible efficiency.
[0012]
Structure of claim 3, wherein further a control device of the vehicular generator according to claim 2, wherein the power generation control unit, estimates the energy efficiency based on the charge and discharge efficiency of power generation efficiency and the storage means of the generator Therefore, it is possible to improve energy efficiency in consideration of a loss in charging / discharging of the power storage means.
[0013]
According to a fourth aspect of the present invention, in the vehicle generator control device according to any one of the first to third aspects, the power generation control unit is configured to output the power generator at a maximum output power that can output the power generator when the vehicle decelerates. Is generated, and the generator is intermittently generated when the vehicle is not decelerated. According to this configuration, energy efficiency can be improved without restricting regenerative braking.
[0014]
According to a fifth aspect of the present invention, in the vehicle generator control device according to any one of the first to fourth aspects, the power generation control unit further stops the power generation of the generator when the vehicle acceleration exceeds a predetermined value. It is characterized by that. According to this configuration, since the generator is stopped at the time of large acceleration, the acceleration performance is improved. At this time, the power storage means takes charge of power supply to the electric load for the vehicle, but after the power generation of the generator is restored, the power storage means is charged again.
[0015]
According to a sixth aspect of the present invention, the vehicle generator control device according to any one of the first to fifth aspects further includes means for detecting an SOC or a voltage of the power storage means, wherein the intermittent power generation mode is the power storage mode. Command the generator to generate power at a predetermined output until the SOC or voltage of the 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 control for stopping the power generation of the generator until it drops to a predetermined value.
[0016]
That is, according to this configuration, the generator is suspended between the two values of the charging state of the power storage means, so that intermittent power generation can be easily performed. Moreover, a voltage may be used for power generation stop determination, and SOC may be used for power generation start determination, or vice versa.
[0017]
According to a seventh 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 comprises a lithium battery. Since the lithium battery has a small charge / discharge loss, energy efficiency can be improved.
[0018]
According to the eighth 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 comprises an electric double layer capacitor. Since the electric double layer capacitor has a small charge / discharge loss, the energy efficiency can be improved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The preferred embodiments of the control device for a vehicle generator according to the present invention will be described in detail with reference to the following examples.
[0020]
(Constitution)
FIG. 1 shows a circuit configuration in Embodiment 1 of the present invention.
[0021]
An assembled battery 1 formed by connecting a plurality of lithium batteries in series supplies electric power to an electric load 2. The generator 3 supplies power to the electric load 2 and charges the assembled battery 1. The generator 3 includes 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 assembled battery 1, a signal line 12 for detecting the voltage of the assembled battery 1, and a signal line 13 from the temperature sensor 10 in the assembled battery 1 are connected to the controller 8. Yes. Furthermore, although the sensor portion is not shown, a signal line 14 from the vehicle speed sensor and a signal line 15 from the generator rotation speed sensor are connected. The controller 8 intermittently controls the field current control switch 7 through the field current control signal line 16.
[0022]
(Operation)
An example of the relationship between the rotational speed of the generator 3 and the maximum output is shown in FIG. When regenerating energy when the vehicle is decelerating, power is generated with an output substantially equal to the maximum output in accordance with the rotational speed. However, in cases other than deceleration, the output required for the generator is significantly smaller than that during regeneration. Conventionally, since the power consumed by the electric load 2 is generated in real time, for example, when the power consumption of the electric load 2 is about 0.2 kW and the generator rotational speed is about 4000 rpm, The operating point is P1 in the figure, and power must be generated with a very small output (about 7%) with respect to the maximum output point Pmax at this rotational speed.
[0023]
An example of the relationship between the output of the generator 3 and the power generation efficiency is shown in FIG.
[0024]
When 0.2 kW is output at 4000 rpm (point A), the power generation efficiency is reduced by about 20% compared to the 1.0 kW output (point B) at which the power generation efficiency reaches the maximum at the same rotation speed, which hinders improvement in fuel consumption. It was.
[0025]
Therefore, in this embodiment, high-efficiency operation is achieved by intermittently generating power at an operating point (point B) with high power generation efficiency so that the average generated power is substantially equal to the power consumed by the electric load 2. It was 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. Assuming that the time is t (min), during the period of T1 ≦ t <T2, the generator generates power with an output of 1.0 kW with high efficiency, and supplies 0.2 kW among them to the electric load, and the remaining 0. 8 kW charges the Li battery. Next, in a period of T2 ≦ t <T3, the generator stops generating power and the Li battery supplies 0.2 kW to the electric load. The same operation is repeated after T3. Since the ratio of the time during which the generator is operating to the time when it is stopped is (T2−T1) / (T3−T1) = 1/5, the generator averages the power consumption of the electrical load. It will output approximately equal power. However, if the output of the generator changes abruptly, the generator torque changes abruptly and gives the driver a sense of incongruity. Therefore, the output of the generator is actually gradually changed so as not to give a sense of incongruity.
[0026]
When the intermittent operation as shown in FIG. 4 is performed, the generated energy is temporarily stored in the battery and then supplied to the electric load. Therefore, when the loss due to charging / discharging of the battery 1 is also taken into consideration, more optimal operation is possible. Become. When energy generated by the generator 3 is temporarily stored in the battery and then supplied to the load 2, due to loss due to charging / discharging of the battery 1, if the power consumption of the electrical load is less than a predetermined value, intermittent The total energy efficiency of the operation is higher, and conversely when the value exceeds a predetermined value, the total energy efficiency is higher when the operation is not intermittent but operates at an output corresponding to the load power consumption in real time.
[0027]
This point will be described in detail below. When operating at an output corresponding to the load power consumption in real time, power is directly supplied from the generator to the electric load, so there is no loss due to charging / discharging of the battery, and the total energy efficiency E1 is
E1 = ηG (PL, N) [%]
It becomes. 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, when intermittent operation is performed at a predetermined output Pconst with high efficiency, energy is temporarily stored in the battery, so that loss due to charging / discharging of the battery occurs, and the total energy efficiency E2 is
E2 = {PL / Pconst} .eta.G (Pconst, N) + (Pconst-PL) / Pconst. {. Eta.G (Pconst, N) / 100}. {. Eta.bat1 (Pconst-PL) / 100}. {. Eta.bat2 (PL). / 100} × 100 [%]
It becomes. Here, ηbat1 (P) is the charging efficiency (%), ηbat2 (P) is the discharging efficiency (%) of the battery, and is a function of each charging power and charging power. Charging efficiency and discharging efficiency vary depending on the internal resistance of the battery. An example in which the internal resistance of the assembled battery 1 is 100 mΩ is shown in FIG. Comparing E1 and E2, if E1 ≥ E2, the most efficient operation is possible by operating in real time according to the output corresponding to the load power consumption, and if E1 <E2, intermittent operation is possible. .
[0028]
FIG. 6 shows an example in which E1 and E2 are compared under the condition that the internal resistance of the assembled battery is 100 mΩ and Pconst = 1.0 kW. When the electric power consumption PL of the electric load is smaller than about 0.8 kW, E1 ≧ E2 is established, so that the output is operated in real time according to the load electric power consumption. When PL is smaller than about 0.8 kW, E1 <E2 Therefore, the control to perform intermittent operation is performed.
[0029]
Next, a method for performing high-efficiency operation control of the generator as described above while efficiently regenerating deceleration energy 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 high-efficiency operation control as described above. On the other hand, in a state where the generator is driven by the energy transmitted from the wheels during deceleration, the generator can regenerate more energy when operated at the maximum output, and thus fuel efficiency is improved. Therefore, in the present invention, it is found from the vehicle speed sensor, the stroke of the brake pedal, etc. that the vehicle is in a decelerating state, and the generator generates power at the maximum output when decelerating. Perform operation control.
[0030]
Since it is obvious that the control described above can be easily performed by the controller 8, further description is omitted.
[0031]
When high-efficiency operation control by intermittent operation is performed at times other than during deceleration, ON / OFF of the generator can be controlled based on the state of charge (SOC) of the battery and the acceleration of the vehicle. A specific control method will be described with reference to FIG. In Step 01, the SOC of the battery is compared with the first predetermined value (SOC-1). If it is smaller, the Charge flag is set to 1 (Step 02). Otherwise, the Charge flag is set to 0 (Step 03). To do.
[0032]
Next, in Step 04, it is determined whether or not the vehicle is in a decelerating state. If the vehicle is in a decelerating state, the generator generates power at the maximum output in Step 05. If the vehicle is not decelerating, it is determined in step 06 whether the vehicle acceleration is equal to or greater than a predetermined value (acc [m / s2]). If it is greater than the predetermined value, power generation is stopped in step 07, otherwise step 08 is performed. To determine whether the Charge flag is 1. When the Charge flag is 1, the battery SOC is further compared with the first predetermined value (SOC-1) at Step 09. When the Charge flag is smaller, at Step 10, the generator is output with high efficiency according to the rotational speed. Power generation is performed. In other cases, power generation is stopped at Step 11, and the Charge flag is set to 0 at Step 12. In Step 08, it is determined whether the Charge flag is 1. If not, Step 13 compares the SOC of the battery with a second predetermined value (SOC-2), and if it is larger, power generation is stopped in Step 14. Otherwise, in Step 15, the generator generates power with an output that becomes highly efficient in accordance with the rotational speed, and in Step 16, the Charge flag is set to 1. 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% And so on. The predetermined value (acc) for determining the acceleration state is set to acc = 0.5 [m / s2], for example.
[0033]
FIG. 8 shows an example of changes over time in vehicle speed, acceleration, battery SOC, and generator output when this control is performed. The details will be described assuming that the time is t and the Charge flag is 1 at t = T1.
[0034]
In the period of T1 ≦ t <T2, the vehicle speed is constant at 40 km / h, the acceleration is 0 [m / s2], the Charge flag is 1, and the SOC is smaller than the first predetermined value (SOC-1 = 60%). Therefore, at Step 10 in FIG. 7, the generator generates power at an output (1.0 kW) with high efficiency according to the rotation speed. Since the electric power consumption of the electric load is about 0.2 kW, 0.2 kW in the generated 1.0 kW is supplied to the electric load, the remaining 0.8 kW is charged to the Li battery, and the SOC increases.
[0035]
In the period of T2 ≦ t <T3, the vehicle is accelerating from 40 km / h to 80 km / h, the acceleration is 0.56 [m / s2], and a predetermined acceleration (acc = 0.5 [m / s2]) Since it is above, a generator stops an electric power generation by Step07. 0.2 kW is supplied from the Li battery to the electric load, and the SOC decreases.
[0036]
In the period of T2 ≦ t <T4, the vehicle is constant at 80 km / h, the acceleration is 0 [m / s2], the Charge flag is 1, and the SOC is smaller than the first predetermined value (SOC-1 = 60%). Therefore, at Step 10, the generator generates power at an output (1.0 kW) that is highly efficient according to the number of rotations. Of the generated 1.0 kW, 0.2 kW is supplied to the electric load, the remaining 0.8 kW is charged to the Li battery, and the SOC increases.
[0037]
At t = T4, the SOC reaches a first predetermined value (SOC-1 = 60%), the generator stops generating power in Step 11, and the Charge flag is set to 0 in Step 12.
[0038]
In the period of T4 <t <T5, the vehicle is constant at 80 km / h, the acceleration is 0 [m / s2], the Charge flag is 0, and the SOC is larger than the second predetermined value (SOC-2 = 50%). Therefore, the generator stops power generation in Step 14. 0.2 kW is supplied from the Li battery to the electric load, and the SOC decreases.
[0039]
At t = T5, the SOC reaches a second predetermined value (SOC-2 = 50%), the generator stops generating power at Step 15, and the Charge flag is set to 1 at Step 16.
[0040]
Similarly, during the period of T5 <t <T9, when the SOC increases and reaches the first predetermined value (SOC-1 = 60%), the power generation is stopped, and then the SOC decreases and the second predetermined value is reached. When (SOC-2 = 50%) is reached, the operation of restarting power generation is repeated.
[0041]
In the period of T9 <t <T10, the vehicle is decelerating from 80 km / h to 0 km / h, and in Step 05, the generator generates power at the maximum output corresponding to the rotational speed. 0.2 kW in the generated electric power is supplied to the electric load, and the rest is charged in the Li battery, and the SOC increases.
[0042]
In the period of T10 <t <T11, the vehicle is stopped at 0 km / h, the acceleration is 0 [m / s2], the Charge flag is 0, and the SOC is a second predetermined value (SOC-2 = 50%). Therefore, the generator stops generating power at Step 14.
[0043]
In the period of T11 <t <T12, the vehicle is accelerating from 40 km / h to 70 km / h, the acceleration is 0.97 [m / s2], and a predetermined acceleration (acc = 0.5 [m / s2]) Since it is above, a generator stops an electric power generation by Step07.
[0044]
At t = T12, the SOC reaches a first predetermined value (SOC-1 = 60%), the generator stops generating power in Step 11, and the Charge flag is set to 0 in Step 12.
[0045]
In the period of T12 <t <T13, the vehicle is constant at 80 km / h, the acceleration is 0 [m / s 2], the Charge flag is 0, and the SOC is larger than the second predetermined value (SOC-2 = 50%). Therefore, the generator stops power generation in Step 14.
[0046]
In the above control, ON / OFF of the generator is controlled based on the SOC of the battery. When the voltage reaches a first predetermined value (for example, 39.0 V), the power generation is stopped based on the battery voltage. Next, control may be performed so that power generation is resumed when the SOC reaches a second predetermined value (for example, 35.0 V).
[0047]
(effect)
(1) Even when the power consumption of the electrical load is small, highly efficient power generation is possible, and fuel consumption 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) Considering losses due to charging / discharging of Li batteries and electric double layer capacitors, the generator operation method is optimized so that the energy efficiency is maximized according to the power consumption of the electric load. Efficient operation control can be performed more effectively.
(4) By performing ON / OFF control of the generator based on the SOC or voltage of the battery, the generator starts generating power after the regenerated energy is used up (except during deceleration), so power generation is not wasted. Fuel consumption 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 the relationship between the rotational speed of the generator and the maximum output.
FIG. 3 is a characteristic diagram showing the relationship between the output of the generator and the power generation efficiency.
FIG. 4 is a timing chart showing changes in power of each part over time.
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 electrical load and total energy efficiency.
FIG. 7 is a flowchart showing a power generation control operation.
8 is a timing chart showing temporal changes in vehicle speed, acceleration, battery SOC, and generator output when the control operation shown in FIG. 7 is performed.
[Explanation of symbols]
1 assembled battery (electric storage means)
2 Electric load for vehicles 3 Generator 8 Controller (power generation control unit)
15 Speed detector

Claims (8)

Power storage means for supplying power to the vehicle electrical load;
A generator for supplying electric power to the power storage means and the electric load for the vehicle;
A power generation control unit for adjusting the output power of the generator,
The power generation control unit, the control unit of the car dual generator that having a discontinuous generating mode the average output power of the generator to intermittently power the generator to be substantially equal to the power consumption of the vehicle electric load ,
The power generation control unit includes a rotational speed detection means for detecting the rotational speed of the generator, and the power generation control unit generates power at the current rotational speed based on a relationship among the rotational speed of the generator, power generation efficiency, and output power stored in advance. A control device for a vehicular generator, wherein output power having good efficiency is intermittently generated by the generator. Power storage means for supplying power to the vehicle electrical load;
A generator for supplying electric power to the power storage means and the electric load for the vehicle;
A power generation control unit for adjusting the output power of the generator,
In the vehicle generator control device having an intermittent power generation mode in which the generator intermittently generates power so that the average output power of the generator is substantially equal to the power consumption of the vehicle electrical load ,
The power generation control unit has a continuous power generation mode in which the generator continuously generates output power substantially equal to the power consumption of the vehicular electrical load, and selects one of the two modes that is more energy efficient. A control device for a vehicular generator. The control device for a vehicle generator according to claim 2 ,
The power generation control unit estimates the energy efficiency based on the power generation efficiency of the power generator and the charge / discharge efficiency of the power storage means. In the control apparatus of the generator for vehicles according to any one of claims 1 to 3 ,
The power generation control unit causes the generator to generate electric power with the maximum output power that can output the generator during vehicle deceleration, and intermittently generates the generator when the vehicle is not decelerated. Control device. In the vehicular generator control device according to any one of claims 1 to 4 ,
The power generator control unit stops the power generation of the generator when the vehicle acceleration exceeds a predetermined value. In the control device of the generator for vehicles according to any one of claims 1 to 5 ,
In the intermittent power generation mode, the generator is instructed to generate power at a predetermined output until the SOC or voltage of the power storage means rises to a first predetermined value. And power generation for the vehicle, wherein the power generation of the generator is stopped until the SOC or voltage of the power storage means reaches the first predetermined value and then decreases to the second predetermined value. Machine control device. The vehicle generator control device according to any one of claims 1 to 6 ,
The control device for a vehicular generator, wherein the power storage means comprises a lithium battery. The vehicle generator control device according to any one of claims 1 to 6 ,
The control device for a vehicular generator, wherein the power storage means comprises an electric double layer capacitor.

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