JP5836068B2 - Vehicle power supply device, electric vehicle - Google Patents

Description

The present invention relates to a vehicle power supply device and an electric vehicle .

  Conventionally, two batteries having different characteristics are provided in the vehicle power supply device, and the generated power of the generator (alternator) is controlled based on the operation state of the vehicle, and the generated power is supplied to these two batteries. Devices have been proposed that improve the energy efficiency of the entire vehicle by controlling charging and discharging of the battery, including charging and power transfer between the two batteries.

  For example, in Patent Document 1, two battery devices (first battery: lead acid battery, second battery: lithium ion battery) are provided in a vehicle power supply device, and the generator DUTY is greater than or equal to a predetermined value. 2 Control for prohibiting charging operation to a battery is disclosed.

  Further, in Patent Document 2, two batteries (a low voltage battery such as a lead acid battery and a high voltage battery such as a lithium secondary battery) are provided in the power supply device, and DC / DC that transfers power between these two batteries is provided. An apparatus for controlling a DC converter and an apparatus for optimizing the charging of these two batteries by the generated power of the alternator and the discharging of these two batteries according to the operating state of the vehicle are disclosed.

JP 2004-229478 A JP 2006-304574 A

  However, in the conventional vehicle power supply devices disclosed in Patent Document 1 and Patent Document 2, for example, the engine efficiency is not taken into account in the transportation of electric power from the low voltage battery to the high voltage battery, and therefore the entire vehicle is Control of power transfer between two batteries that maximizes efficiency has not been performed. The alternator for charging the low-voltage battery is controlled by detecting the current amount of the exciting coil of the alternator or the duty ratio of the on / off switch for controlling the current amount. Since the duty ratio changes greatly due to fluctuations in the external load, power transfer between the two batteries cannot be performed stably.

A power supply device for a vehicle according to the present invention includes an alternator connected to an engine, a first power supply system having a low voltage battery to which the alternator and an electric load are connected, and a second power source having a high voltage battery to which the electric load is connected. A power supply system; a DC / DC converter that converts the power of the first power supply system into a voltage to charge the second power supply system; a first control device that controls the engine and the alternator; and the DC / DC converter. A second control device for controlling, wherein the first control device sets a throttle opening of the engine so as to operate the engine under a maximum efficiency operating condition, and based on a voltage of the low-voltage battery. controlling the alternator, the second control device, said ol corresponding to maximum efficiency operating condition of the engine An overcurrent region in which the voltage of the low-voltage battery after the voltage drop corresponding to the load current of the alternator when the DC / DC converter is operated exceeds the limit of the power generation capacity of the alternator The charging state of the first power supply system and the second power supply system is controlled by controlling the output current of the DC / DC converter so as not to fall below a predetermined lower limit voltage corresponding to.
An electric vehicle according to the present invention includes the vehicle power supply device.

  With the vehicle power supply device according to the present invention, in a hybrid vehicle having two batteries (a low voltage battery and a high voltage battery), charge / discharge control of these batteries can be performed so as to optimize engine efficiency. In addition, the control of the generator that charges the low-voltage battery can be made strong against external fluctuations.

It is a block diagram which shows the outline of the structural example of the vehicle provided with the power supply device for vehicles by this invention. It is a figure which shows the structural example of the engine controller of the vehicle power supply device by this invention with an alternator and other various sensors and input / output devices. FIG. 4 is a diagram showing a change in a control amount (duty) of an exciting coil current of an alternator 51 with respect to a voltage fluctuation of a low voltage battery 50. FIG. 6 is a diagram showing a state of voltage drop of the low voltage battery 50 due to an increase in load current to the alternator 51. It is the figure which showed the high efficiency area | region of the engine fuel consumption with the contour map of an engine speed and an engine output torque. It is the figure which showed the example of charge control of the lithium ion battery which comprises a high voltage battery. FIG. 6 is a flowchart of an exciting coil current amount change speed limiting operation of the alternator 51. It is a chart figure showing the relation between the electric load fluctuation of alternator 51, and the voltage fluctuation of low voltage battery 50. It is a figure explaining the vehicle control flow in the case of switching the operation mode of the DC / DC converter 153 in the vehicle power supply device by this invention. It is a figure explaining the vehicle control flow in case the operation mode of the DC / DC converter 153 in the vehicle power supply device by this invention is constant voltage control of a 1st power supply. It is a figure explaining the general | schematic flow of the whole operation | movement of the vehicle power supply device by this invention.

Hereinafter, an embodiment for carrying out the present invention will be described with reference to FIGS.
FIG. 1 shows an embodiment of a hybrid vehicle equipped with a vehicle power supply device according to the present invention. The hybrid vehicle includes an electric load such as a starter 10 and a low voltage battery 50 to which a generator (alternator) 51 is connected by a wiring 151. Lithium ion battery that supplies DC power to a single power supply system, a voltage converter (DC / DC converter) 153 that converts the power of the first power supply system, and an inverter 159 that controls three-phase power supply to the motor 156 And a second power supply system comprising a high voltage battery 152. The inverter 159 also performs control for converting the regenerative power of the motor 156 into DC power and charging the second power supply system. The low voltage battery 50 is a lead acid battery generally used in automobiles, and is used at a state of charge (SOC) of nearly 100%.

  Most of the power supply to the low-voltage electric load (auxiliary equipment such as an air conditioner and audio) during engine rotation is provided by the outputs of the low-voltage battery 50 and the generator (alternator) 51. The motor 156 and the engine 160 are operated by an instruction signal from the hybrid controller (HCM) 157. For example, in the starter 10, an instruction signal from the HCM is input to the engine controller (ECM) 71 via the wiring 155, and the engine controller 71 further outputs an operation signal to the starter 10 via the wiring 158. Start.

  FIG. 2 shows a configuration example of the engine controller 71 in the vehicle power supply device according to the present invention together with the alternator 51 and other various sensors and input / output devices. CPU 100 which is an arithmetic unit, ROM 101 which is a read-only memory, RAM 102 which is a memory which can be read and written, a backup RAM 111 whose contents are not cleared even when the ignition switch 72 is turned off, an interrupt controller 104, a timer 105, an input processing circuit 106 and an output processing circuit 107, which are connected by a bus 108.

  Based on various information processed by the input processing circuit 106, the CPU 100 uses a backup RAM 111 that can retain the stored contents even when the RAM 102 and the ignition switch 72 are off based on a program stored in the ROM 101. Perform various processes. At this time, interrupt processing is also performed in a timely manner by an interrupt command issued from the interrupt controller 104 based on information from the timer 105 and the input processing circuit 106.

  The power generation system will be described. An alternator 51 includes a rotor formed by winding an exciting coil 54 around the outer periphery, and three-phase windings 53a, 53b, 53b, 53b, The rotor is configured to rotate around the crankshaft of the engine 160. The output terminals of the three-phase windings 53a, 53b, 53c of the alternator 51 are connected to a three-phase full-wave rectifier circuit 55 in which, for example, three sets of two diode series circuits are connected in parallel. The output is rectified and supplied to the low voltage battery 50 for charging.

  The engine controller 71 also includes a power generation control program that adjusts the output voltage of the alternator 51 while detecting the voltage of the low voltage battery 50. The current amount of the exciting coil 54 is controlled by the exciting coil driving circuit 56 as follows. The result obtained by the input processing circuit 106 having a voltage detection function for detecting the voltage of the low-voltage battery 50 is compared with the result obtained by calculating the power generation target voltage according to the operating state of the engine 160 described above. The exciting coil current amount of the exciting coil 54 is calculated so that the voltage of 50 approaches the target voltage. A drive signal corresponding to the excitation coil current amount is output to the excitation coil drive circuit 56.

FIG. 3 shows a change in the excitation coil current control amount of the alternator 51, that is, the duty of the excitation coil drive circuit, with respect to the voltage fluctuation of the low voltage battery 50. The lead acid battery used for the low voltage battery 50 is used in a charged state where the SOC is as close to 100% as possible because the performance deteriorates and the life is shortened when the voltage continues to be low after discharging. Therefore, depending on the voltage deviation of the rated voltage of the low voltage battery 50, the excitation coil current control amount of the alternator 51 is set to be large. That is, when the voltage of the low-voltage battery 50 is lower than the target voltage, the exciting coil current control amount is set large, and conversely, when the voltage is higher than the target voltage, the exciting coil current amount of the alternator 51 is set small. Keep the voltage constant. This target voltage is normally the rated voltage of the low-voltage battery 50, and is indicated by a voltage deviation of 0 V in FIG. In other words, this operation performs feedback (F / B) control that compensates for the voltage drop generated by the load current.
In the power generation operation of the alternator 51, charging of the low voltage battery is given the highest priority. Therefore, the alternator 51 operates so as to keep the voltage of the low voltage battery 50 constant as described above. In the description of the additional electric load to the alternator 51 described below, the load for charging the low voltage battery is excluded.

  FIG. 4 shows a general operation example of a voltage drop of the low-voltage battery 50 due to an increase in the load current to the alternator 51. As shown in FIG. 3, when the load current due to various electric loads increases, the voltage drop of the low-voltage battery 50 increases, so that the current amount of the exciting coil is adjusted to be large. The amount of current is set to 100%. Therefore, when the load current to the alternator 51 is an overcurrent, the voltage drop of the low voltage battery 50 exceeds the above 0.5V, so that the voltage falls below the lower limit voltage and the voltage becomes unstable. As will be described later, in this embodiment, when the electric load due to the operation of the DC / DC converter 153 further becomes the load of the alternator 51, control is performed so that the load current to the alternator 51 does not enter this overcurrent region.

  FIG. 5 schematically shows fuel efficiency derived from the relationship between the engine speed and the engine output torque. As shown in the figure, it can be seen that the region where the fuel efficiency is high is a low to medium engine speed, and the engine output torque is a higher load than the medium. Therefore, in the present invention, when the load of the auxiliary machine is insufficient for the operation at the maximum efficiency point, the load is further added to the generator 51 by operating the DC / DC converter 153, By moving the operating point of the engine to its maximum efficiency point, the engine is operated with high efficiency.

  FIG. 6 is a diagram illustrating an example of charge control of a single battery cell of the lithium ion battery 152 constituting the second power supply system. When charging a single battery cell of a lithium ion battery, it is common to perform constant current control when the voltage between terminals is lower than the rated voltage corresponding to SOC 100%, and constant voltage control when the voltage between terminals is high. is there. Such a device for charging a lithium ion battery with a constant current / constant voltage, that is, a DC / DC converter is commercially available and widely used, and detailed description thereof is omitted here. In the following description, it is assumed that a DC / DC converter for charging a lithium ion battery with such a constant current / constant voltage is used.

In the example of FIG. 6, the case of one single battery cell of the lithium ion battery 152 is shown for easy understanding. The high voltage battery (lithium ion battery) 152 is usually configured by connecting a plurality of cell groups in which a plurality of such single battery cells are connected in series to each other in series or in series and parallel. With such a configuration, a high voltage output reaching several hundred volts is obtained. Therefore, the SOC 100% state of the high voltage battery 152 corresponds to the total voltage of all the unit cells being a rated voltage.
Although not shown in FIG. 1, the high-voltage battery 152 monitors the total voltage (voltage between terminals of the high-voltage battery or output voltage) and the charge state of individual unit cells constituting the high-voltage battery 152. Is monitored / controlled by a high voltage battery control device (not shown). In addition, the high-voltage battery control device performs the so-called balancing discharge so that the state of charge of each unit cell is aligned so that the state of charge of each unit cell is substantially the same. This description is omitted.

  The constant current control region for charging by the DC / DC converter 153 is intended for charging in a short time with a large current, but there is no problem whether the current is small or large. Therefore, in this embodiment, during constant current control, the load on the alternator 51 is controlled so that the engine operation becomes the maximum efficiency point in the first power supply system. For this purpose, a charging current corresponding to an operation load of the DC / DC converter 153 corresponding to an additional load to the alternator 51 is supplied from the DC / DC converter 153 to the second power supply system. When the lithium ion battery 152 is sufficiently charged, that is, when the SOC is 100%, the DC / DC converter 153 is controlled at a constant voltage as described above, and charged above the rated voltage corresponding to the SOC 100%. Not. With a very small charging current, charging is performed for a slight decrease in SOC due to self-discharge or balancing discharge.

<Example of effects of vehicle power supply device according to the present invention>
As described above, by using the vehicle power supply device according to the present invention, it is possible to provide a vehicle power supply device that can transmit and receive power between the first power supply system and the second power supply system strongly and stably against disturbance. An example of this effect will be described with reference to FIGS.

  FIG. 7 is a flowchart relating to the change speed limit of the exciting coil current amount of the alternator 51. In step 220, the battery temperature (TVB) is calculated. Based on the calculated battery temperature, in step 221, the target generated voltage ( VBSET) is calculated, the battery voltage (VB) is detected at step 222, and the voltage deviation of the low voltage battery 50 with respect to the target power generation voltage of the alternator 51 is calculated at step 223.

  By detecting that the voltage of the low-voltage battery 50 has decreased by a predetermined value or more in step 225, it is detected that the electric load has been turned on from OFF. If it is detected that the voltage of the low-voltage battery 50 has decreased by a predetermined value or more, the rate of increase of the exciting coil current control amount ALTDTY of the alternator 51 is limited in step 226 to detect that the electrical load has been turned on from OFF. If not, control is performed without limiting the rate of increase of ALTTDTY (see, for example, JP-A-8-284719).

By such control, charging with a charging voltage suitable for the state of the low-voltage battery 50 avoids shortening the life of the low-voltage battery 51, and by a sudden increase in load torque to the alternator 51 when an electric load is applied. It is possible to realize a power generation control device that does not decrease the engine speed.
On the other hand, when such control is in operation, the drive DUTY of the alternator 51 (excitation coil current control amount, that is, the duty ratio of on / off of the excitation coil drive circuit) becomes DUTY that does not match the actual load. If the load is estimated by this, an error in load calculation of the alternator 51 is caused.

  FIG. 8 is a chart showing the relationship between the electric load fluctuation of the alternator 51 and the voltage fluctuation of the low voltage battery 50. In this example, since the excitation coil current amount of the alternator 51 is controlled using the above-described method for determining the change rate of the excitation coil current amount of the alternator 51 in FIG. 7, the electrical load on the alternator 51 is switched from OFF to ON. Although the voltage drop of the low voltage battery 50 is sometimes large, the effect of preventing the alternator 51 from lowering the rotational speed can be obtained, and the voltage rise is slow, so that the driver is less likely to notice changes in illuminance such as headlamps. It is controlled. On the other hand, when the electric load is turned from ON to OFF, the fluctuation of the power supply voltage is small, the power supply voltage hardly increases and there is almost no change in illuminance.

FIG. 9 is an example of a control flow for switching the operation mode of the DC / DC converter 153 in the embodiment of the vehicle power supply device according to the present invention.
In step 201, the voltage of the second power supply system is detected. In step 202, the charging voltage control of the DC / DC converter 153 is switched based on the characteristics of FIG. That is, when the voltage between the terminals of the lithium ion battery 152 of the second power supply system is lower than a predetermined voltage (for example, rated voltage), charging by constant current control is performed.

  In step 203, a charging operation is performed when charging by constant voltage control is selected by the DC / DC converter 153. In this constant voltage control, the charging current is very small, and therefore the load of the DC / DC converter 153 is small. Therefore, the first power supply system side which gives a sufficient load to the alternator 51 to make the engine operation the highest efficiency point is provided. There is no control. Step 204 indicates that the DC / DC converter 153 performs constant voltage control.

On the other hand, if the voltage between the terminals of the lithium ion battery 152 of the second power supply system is lower than the predetermined voltage in step 202, the mode is switched to a mode in which the lithium ion battery 152 of the second power supply system is charged by constant current control. Proceed to step 205. In step 205, the operation of the alternator 51 is controlled so that the engine efficiency becomes the highest efficiency point.
Here, an increase in load due to the operation of the DC / DC converter 153 (charging of the lithium ion battery 152 of the second power supply system under constant current control) causes the alternator 51 to operate so that the engine efficiency becomes the highest efficiency point. Set to That is, the load of the DC / DC converter 153 (the charging current to the lithium ion battery 152 of the second power supply system) is set so as to be an additional load on the alternator 51 that maximizes the engine efficiency.
As will be described later, an example of control of the operation of the alternator 51 in step 205 so that the engine efficiency is set to the highest efficiency point will be described with reference to FIG.

  In step 205, the amount of charging current to the lithium ion battery 152 of the second power supply system is calculated. In step 206, this is set in the DC / DC converter 153. In step 207, the lithium ion battery 152 of the second power supply system is set. Charge with constant current control.

  In parallel with the operations of Step 206 and Step 207, the engine controller 71 outputs a predetermined voltage between the terminals of the lead acid battery 50 at Step 208 so that the engine efficiency becomes the highest efficiency point at Step 208. Set to 107. In step 209, the output processing circuit 107 adjusts the exciting coil current amount by controlling the exciting coil drive circuit 56 so that the voltage between the terminals of the lead acid battery 50 becomes the predetermined voltage. This control is performed by the feedback control of the alternator 51 described above with reference to FIG.

  FIG. 10 shows an example of calculating the load on the alternator 51 in step 205 described above. In step 210, the engine intake air amount is taken in, and in step 211, the engine target load TP (corresponding to the load at the highest efficiency point) is determined by the intake air amount Qa and the engine speed Ne, and the engine rotation as shown in FIG. It is calculated from the relationship between the number and the engine output torque. The load is calculated by calculating the air amount per unit rotation by dividing the intake air amount Qa by the engine speed Ne. In this embodiment, an electric load such as a DC / DC converter 153 or the above-mentioned auxiliary machine (air conditioner, etc.) is added to operate the engine at the highest efficiency point. Enlarge. Note that the pumping loss can be reduced by performing such control to increase the throttle opening.

  In step 213, the load at the maximum efficiency point corresponding to the engine speed is calculated. In step 214, the target power generation load LDALT is calculated from the difference from the load calculated in step 211. Next, the current voltage V1 of the lead acid battery 50 is taken in at step 215, the target power generation voltage TV is calculated at step 216, and the constant voltage control of the DC / DC converter 153 is performed based on this.

  Although not shown in FIG. 10, in step 213, each electric load including the DC / DC converter 153 is selected so that the engine target load TP becomes the highest efficiency point of the engine. Further, since the difference between the engine load corresponding to the engine speed Ne detected in step 212 and the engine target load TP can be supplied to an additional electric load including the DC / DC converter 153, DC / DC The charging current when the converter 153 charges the lithium ion battery 152 with constant current control is determined from the difference between the engine load corresponding to the engine speed Ne and the engine target load TP. That is, if the load corresponding to the maximum charging current of the lithium ion battery 152 in the constant current control of the DC / DC converter 153 is smaller than the difference between the engine load TP calculated in step 211 and the engine target load TP, DC / The DC converter 153 can charge the lithium ion battery 152 with the maximum charging current.

Alternatively, if the difference between the engine load TP calculated in step 211 and the engine target load TP is sufficiently large, other electric loads can be added as additional electric loads.
Conversely, it is necessary to supply the power generation amount of the alternator 51 corresponding to the difference between the engine load TP calculated in step 211 and the engine target load TP to another electrical load that has priority over the electrical load of the DC / DC converter 153. In some cases, it is necessary to reduce the amount of current supplied to the electric load of the DC / DC converter 153. In such a case, the charging current of the DC / DC converter 153 is limited, and the electric load of the DC / DC converter 153 is reduced.
In this way, by adjusting the charging current in the constant current control of the DC / DC converter 153, the engine is operated at the highest efficiency point and charging is performed so as to compensate for the shortage of the charging amount of the second power supply system. Can do.

The above description is summarized and FIG. 11 shows an outline of an operation flow of the vehicle power supply device according to the present invention from the start of the vehicle. The entire operation flow is controlled by a hybrid controller (HCM) 157. As shown in FIG. 2, engine control and detection of various parameters indicating the engine operating state and control of the alternator 51 are performed by an engine controller (ECM) 71 controlled by the hybrid controller 157.
As can be seen from the above description, charging of the lithium ion battery 152 using the DC / DC converter 153 of the vehicle power supply device according to the present invention is performed in a state where the power generation capability of the alternator 51 is sufficient, and to the alternator 51. It is preferable to carry out in a state in which the fluctuation of the load is not large. Therefore, the operation of the vehicular power supply apparatus according to the present invention is mainly performed when the vehicle is idling or during high-speed cruise.

  When the electric vehicle is started (engine start) in step 301, the low-voltage side control operations in steps 302 to 308 and step 311 and the high-voltage side control operations in steps 309 and 310 and step 311 are performed in parallel.

Simultaneously with the start of the vehicle in step 301, automatic control is started in which the alternator 51 performs power generation so that the state of charge of the low voltage battery 50 is a predetermined value. This is as described above with reference to FIGS.
In step 302, the load of the alternator 51 in this state (excitation coil current or on / off duty ratio of the excitation coil drive circuit 56) is detected. Subsequently, at step 303, the engine load described with reference to FIG. 10 is detected.

  In step 304, the highest efficiency point of the engine 160 described in step 213 of FIG. 10 is stored in a memory area (not shown) of the hybrid controller (HCM) 157 or the engine controller (ECM) 71, as shown in FIG. Calculated from various data. This maximum efficiency point is, for example, the maximum efficiency point at the engine idling speed at the start of the vehicle, and at the high speed cruise, the maximum efficiency point at that speed.

In the control on the high voltage side, the voltage across the terminals of the high voltage battery 152 is detected in step 310 in parallel with the control on the low voltage side. The inter-terminal voltage of the high voltage battery 152 is measured by a high voltage battery control device not shown in FIG. 1, and the measurement result is transmitted to the hybrid controller 157 via a communication circuit (not shown).
Subsequently, at step 311, the charging mode of the DC / DC converter 153 is selected based on the voltage between the terminals. For example, the constant current charging mode is selected if the voltage between the terminals of the high voltage battery 152 is equal to or lower than the charging state (SOC 100%) corresponding to the rated output, and the constant voltage charging mode is selected if it is determined that the SOC is 100%. Is done.

In step 305 of the low-voltage side control, the alternator 51 load (power generation amount) for generating the engine output (torque) at the engine maximum efficiency point calculated in step 304 is changed to the hybrid controller (HCM) 157 or the engine controller ( ECM) 71 is calculated from data (not shown) stored in a memory area (not shown) of 71, and the difference from the engine load detected in step 303 is calculated as alternator 51 load margin (power generation margin).
The operations in steps 303 to 305 described above correspond to the operations in steps 210 to 214 in FIG.

In step 306, an additional load that satisfies the load margin of the alternator 51 calculated in step 305 is selected from the DC / DC converter 153 and other auxiliary machines. At this time, an auxiliary machine is selected in consideration of the priority of each supplementary note.
For example, if the SOC of the high voltage battery 152 is low, this is preferentially used as an additional load. Alternatively, when the SOC of the high voltage battery 152 is sufficiently high and the driver desires to use air conditioning, this air conditioning load is given priority. Furthermore, when the SOC of the high voltage battery 152 is low and the use of other auxiliary equipment is necessary, the control of the DC / DC converter 153 and the use of other auxiliary equipment to limit the charging current of the high voltage battery Can be combined. Selection of such an auxiliary machine and adjustment of the charging output of the DC / DC converter 153 are performed by the hybrid controller 157. At this time, as described above with reference to FIGS. 3 and 4, the selection is made in consideration of the load of the auxiliary machine so that the voltage of the first power supply system does not fall below a predetermined lower limit voltage.

  In step 307, when the DC / DC converter 153 is selected as an additional load to the alternator 51 as described above, the DC / DC converter 153 corresponding to the output of the DC / DC converter 153 under the above conditions is selected. The operating load is calculated. The calculation of the operating load is performed using, for example, data on the relationship between output and power consumption of the DC / DC converter 153 stored in a memory area (not shown) of the hybrid controller 157.

In steps 308, 309, and 312, the engine 160, alternator 51, and DC / DC converter 153 are changed depending on the operating load and various parameters during operation of the engine 160, alternator 51, and DC / DC converter 153 calculated in steps 304 to 307. Each works.
At this time, the alternator 51 performs the power generation operation as described above with reference to FIGS.

  The charging of the high voltage battery 152 by the operation of the DC / DC converter 153 is repeatedly performed as appropriate while the hybrid vehicle is in operation. The charging of the high voltage battery 152 is also performed when the charging current of the high voltage battery 152 by the DC / DC converter 153 is limited based on the load of the alternator 51 and the operating status of various auxiliary machines including the DC / DC converter 153. Is repeated over a long period of time.

  When the vehicle stops in step 313, all the above controls are also stopped, and the operation ends.

As described above, the power generation capacity is considered by optimally controlling the voltage of the first power supply system (low voltage battery 50) by the power generation load considering the efficiency of the internal combustion engine using the vehicle power supply device according to the present invention. A power supply that is resistant to external disturbances that achieves improved efficiency of the internal combustion engine by using a generated load, and that uses a voltage detection value to control the generator, so that the S / N ratio is high and the generator is responsive. A system can be realized.
Further, in the vehicle power supply device according to the present invention, the operation of the internal combustion engine can be performed at the highest efficiency point by controlling the power conversion amount of the voltage conversion device (DC / DC converter) 153, so that the fuel efficiency is improved. . Further, since the F / B is performed by detecting the voltage of the low-voltage battery 50 instead of the DUTY of the alternator 51, it is resistant to disturbances, and the effect of the responsiveness of the generator to the fluctuation of the electric load is less than that of the DUTY. There is.

  The above description is an example of embodiments of the present invention, and the present invention is not limited to these embodiments and examples. Those skilled in the art can implement various modifications without impairing the features of the present invention.

1 Throttle sensor
2 Air flow sensor
3 Water temperature sensor
5 Vehicle speed sensor
7 Crank angle sensor
8 O2 sensor 9 Power steering switch 10 Starter switch 11 Air conditioner switch 12 Headlight switch 13 Cam angle sensor
14 Accelerator sensor
20 Fuel pump
23 Injector
30 Igniter
40 Throttle valve 41 ISC valve 50 Low voltage battery (first power supply system)
51 Alternator 53a, 53b, 53c Stator three-phase winding 54 Excitation coil 55 Three-phase full-wave rectification circuit 56 Excitation coil drive circuit 71 Engine controller (ECM)
74 Air conditioner clutch 75 Radiator fan relay 76 Charge lamp 100 CPU
101 ROM
102 RAM
104 Interrupt controller 105 Timer 106 Input processing circuit
107 Output processing circuit
108 Bus
111 Backup RAM
151 Wiring 152 High-voltage battery (second power supply system)
153 DC / DC converter 154 Wiring 155 Wiring 156 Motor 157 Hybrid controller (HCM)
158 Wiring 160 Engine

Claims (7)

An alternator connected to an engine, a first power supply system having a low voltage battery to which the alternator and an electric load are connected, a second power supply system having a high voltage battery to which an electric load is connected, and the first power supply system A DC / DC converter that converts the power of the power supply to charge the second power supply system, a first control device that controls the engine and the alternator, and a second control device that controls the DC / DC converter, A vehicular power supply device comprising:
The first control device sets the throttle opening of the engine so as to operate the engine under the maximum efficiency operating condition, and controls the alternator based on the voltage of the low-voltage battery,
Said second control device, Ri Do a load of maximum efficiency the alternator corresponding to the operating condition of the engine, and the voltage after drop corresponding to said alternator load current when operating the DC / DC converter By controlling the output current of the DC / DC converter so that the voltage of the low-voltage battery does not fall below a predetermined lower limit voltage corresponding to an overcurrent region exceeding the limit of the power generation capacity of the alternator, The power supply system for vehicles which controls the charge condition of a power supply system and said 2nd power supply system. The vehicle power supply device according to claim 1,
The second control device controls the output current of the DC / DC converter based on a difference between an engine load corresponding to the engine speed and an engine target load corresponding to the maximum efficiency operating condition of the engine. Vehicle power supply device. In the vehicle power supply device according to claim 1 or 2,
The first control device sets a target power generation voltage of the alternator corresponding to the maximum efficiency operating condition of the engine, and feedback-controls the alternator so that the voltage of the low voltage battery becomes the target power generation voltage Power supply. In the vehicle power supply device according to any one of claims 1 to 3,
At least one of the auxiliary machines connected to the alternator including the DC / DC converter is connected to the alternator electrical load so that the electrical load of the alternator corresponding to the maximum efficiency operating condition of the engine is set. The power supply device for vehicles provided with the auxiliary machine selection part selected as. In the vehicle power supply device according to claim 4,
The auxiliary machine selection unit is a vehicle power supply device that determines an auxiliary machine to be selected as an electric load of the alternator based on a charge state of the high voltage battery and a priority of each auxiliary machine. In the vehicle power supply device according to any one of claims 1 to 5,
When the charge rate of the high voltage battery is high and close to full charge, the second control device controls the charge state of the second power supply system by controlling the DC / DC converter at a constant voltage, The control device is a vehicle power supply device that sets a throttle opening of the engine that is smaller than a throttle opening that causes the engine to operate under a maximum efficiency operation condition. An electric vehicle comprising the vehicle power supply device according to any one of claims 1 to 6.

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