JP2006205867A - Electric power supply system and electric power supply control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a sense of discomfort of an occupant accompanying operation stop of a load by avoiding the operation stop of the load. <P>SOLUTION: A load control means 4 compensates shortage of supplied electric power by reducing effective electric power supplied to the load by controlling a duty ratio of the load driving PWM out of the loads 11a, 11b, 11c, ... when the available electric power to be supplied to the loads 11a, 11b, 11c, ... is lowered. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power supply system and a power supply control method for supplying power to a load mounted on a vehicle.

  In recent years, electric loads mounted on vehicles such as automobiles have been steadily increasing, and load driving configured by only an electric system without mechanical connection between an operation device and an actuator such as a by-wire system. Even when the power that can be supplied to the load is reduced due to the introduction of the system, it is required that power can be reliably supplied to an important load.

  In order to respond to such a request, a technique has been proposed in which loads are grouped to set a priority for each group, and a priority is set for each load in the group (see, for example, Patent Document 1). ). According to this technology, power can be supplied from a load with high priority when the available power decreases, and when a new load is added to the vehicle, the priority is assigned within the group to which the load belongs. It is possible to cope with this by simply changing

There is also a technology that changes the priority according to the difference between the load power supply request start timing, the occupant's operation request operation frequency, the load operation state target level, etc. It has been proposed (see, for example, Patent Document 2).
JP 2004-142661 A JP 2004-194495 A

  However, in the above-described conventional technology, when the power required by the load exceeds the suppliable power, it is inevitable that the operation of the load with low priority is stopped, so that the passengers feel uncomfortable. was there.

  The present invention was devised in view of the conventional situation as described above, and is an electric power capable of avoiding a load operation stop as much as possible and reducing passenger discomfort associated with the load operation stop. An object of the present invention is to provide a supply system and a power supply control method.

  In order to achieve the above object, the present invention controls the duty ratio of a load driven by PWM (Pulse Width Modulation) when the suppliable power that can be supplied to the on-vehicle load decreases. Thus, the effective power supplied to the load is reduced. As a result, power consumption can be reduced without stopping the operation of the load, and it is possible to cope with a decrease in suppliable power.

  According to the present invention, even when the suppliable power that can be supplied to the load is reduced, it is possible to avoid the operation stop of the load as much as possible, and to reduce the discomfort of the occupant accompanying the operation stop of the load. Can do.

  Hereinafter, specific embodiments of a power supply system to which the present invention is applied will be described in detail with reference to the drawings.

(First embodiment)
First, a power supply system according to a first embodiment to which the present invention is applied will be described.

  The configuration of the power supply system of this embodiment is shown in FIG. This power supply system is a system for supplying power to a plurality of loads 11a, 11b, 11c,... Mounted on a vehicle such as an automobile, and the generator 1 and a battery are used as load driving power sources. 2 are provided. Further, this power supply system includes a load current sensor 3 that detects currents flowing through a plurality of loads 11a, 11b, 11c,..., And load control that controls operations of these loads 11a, 11b, 11c,. Means 4 and power source control means 5 for calculating the power that can be supplied to the loads 11a, 11b, 11c,... The power supply system further includes a battery current sensor 6 that detects a current output from the battery 2, a battery temperature sensor 7 that detects the temperature of the battery 2, and a generator control means 8 that controls the generator 1. I have. In FIG. 1, solid lines connecting the respective parts indicate power supply lines, and broken lines indicate signal lines.

  In the power supply system of the present embodiment configured as described above, the power supply control means 5 includes the current values flowing through the loads 11a, 11b, 11c,... Detected by the load current sensor 3, and the load control. Based on the information indicating the state of each of the loads 11a, 11b, 11c,... Supplied from the means 4, the total load required power required for all the loads 11a, 11b, 11c,. Is calculated. Further, the power supply control means 5 includes the output current value of the battery 2 detected by the battery current sensor 6, the temperature of the battery 2 detected by the battery temperature sensor 7, and the generator 1 supplied from the generator control means 8. Based on the information indicating the state of the power supply, the power that can be supplied to the loads 11a, 11b, 11c,.

  Further, the load control means 4 controls the power supply from the generator 1 or the battery 2 to the loads 11a, 11b, 11c,..., And controls the operations of these loads 11a, 11b, 11c,. . In particular, in the power supply system of the present embodiment, when the power that can be supplied to these loads 11a, 11b, 11c,... Decreases and the total load power exceeds the power that can be supplied, load control is performed. The means 4 reduces the effective power supplied to the load by controlling the duty ratio of the load driven by PWM (Pulse Width Modulation) among these loads 11a, 11b, 11c,. This makes it possible to compensate for the shortage of available power.

  In such a power supply system of this embodiment, it is desirable to set priorities for all of the loads 11a, 11b, 11c,. For example, as shown in FIG. 2, the priority is set based on the importance from the viewpoint of the vehicle. Specifically, when there is a load that holds the steering or braking function of the vehicle, the priority is set high as the highest importance of this type of load. In addition, for example, a load for maintaining the vehicle traveling function such as a fuel pump and a throttle motor, a load for ensuring driver visibility such as a headlamp and a wiper motor, a load for informing the vehicle behavior to the surroundings such as a stop lamp and a tail lamp, When there is a load that ensures the convenience and comfort of the driver such as radiator fan motor, blower motor, and power window, and a load that supplements the convenience and comfort of the driver such as fog lamp, room lamp, and rear defogger. Priority is set on the order of high importance. In addition, when there are a plurality of loads having the same importance, a higher priority is set for a load having a higher use frequency.

  In the power supply system of the present embodiment, for supplying power to the loads 11a, 11b, 11c,... According to the control flowchart as shown in FIG. A series of controls are performed.

  First, after the ignition switch is turned on, when any load is turned on or the output level is changed in step S1, the power supply control means 5 performs load control on the load operation state change request. It detects from the means 4 and starts control.

  When the control is started, the power supply control unit 5 starts the control in step S <b> 2, the predicted power consumption value of the load whose output level is increased or the on state obtained from the load control unit 4, and the already on state obtained from the load current sensor 3. The total load power requirement is calculated by adding the total power consumption value of the loaded load.

  Further, in step S3, the power supply control means 5 calculates the generated power of the generator 1 based on the rotational speed and field current of the generator 1 obtained from the generator control means 8, and the power supply control means. 5 is calculated based on the voltage of the battery 2 detected by the battery 5, the current of the battery 2 obtained from the battery current sensor 6, the temperature of the battery 2 obtained from the battery temperature sensor 7, and the like. The sum of the power that can be supplied to the loads 11a, 11b, 11c,... Is calculated by adding the generated power of the machine 1 and the dischargeable power of the battery 2.

  Then, in step S4, the power control unit 5 compares the total load required power with the suppliable power. Here, when the total load required power is smaller than the suppliable power, the power is sufficient, so in step S5, the power is supplied to all the loads 11a, 11b, 11c,. A power supply command is output from the power supply control means 5 to the load control means 4 so as to be supplied. As a result, under the control of the load control means 4, power is supplied at a specified value to all the loads 11a, 11b, 11c,... (Step S5). On the other hand, when the total load required power is larger than the suppliable power, the power is insufficient, so that the power control means 5 outputs a required power reduction request to the load control means 4, and the power supply A necessary power reduction routine whose details will be described later is executed by the cooperation of the control means 5 and the load control means 4 (step S6).

  Then, when the necessary power reduction routine in step S6 is executed and the required power for the entire load becomes smaller than the power that can be supplied, the process proceeds to step S5, and the load control means 4 controls the process. Thus, power supply reflecting the processing in the required power reduction routine is performed on the loads 11a, 11b, 11c,. In the power supply system of the present embodiment, the above series of control is repeatedly performed while the ignition switch is on, and the series of control ends when the ignition switch is off (step S7). ).

  Here, an example of the required power reduction routine executed in step S6 described above will be described. This required power reduction routine comprises a series of procedures shown in FIG. 4, for example.

  In the power supply system of the present embodiment, as a precondition, a duty ratio of a plurality of stages that can be switched with respect to a load that is PWM-driven among the loads 11a, 11b, 11c,. For example, a three-stage duty ratio is set in advance. The duty ratio of a plurality of stages in each PWM-driven load can be arbitrarily set, but the lower limit value of the duty ratio is preferably a value that can secure a minimum voltage for compensating the performance of the load. As for the load of the lamp system, it is desirable to set the level satisfying the legal illuminance as the lower limit value of the duty ratio.

  When the required power reduction routine is started, first, in step S11, a load having a low priority with respect to the load driven by PWM so that the effective power can be lowered by the power shortage by the control by the load control means 4 A process for decreasing the duty ratio one step at a time is performed.

  Subsequently, in step S12, the power control unit 5 determines the power consumption predicted value of the load after power reduction obtained from the load control unit 4 and the load after power reduction obtained from the load current sensor 3. Is added to the total power consumption value to calculate the load power consumption after power reduction.

  Then, in step S13, the power supply control means 5 compares the total load required power with the suppliable power. Here, when the required power of the entire load becomes smaller than the power that can be supplied due to the reduction of the duty ratio of the load to be driven by PWM, the shortage of power has been solved, so the required power reduction routine is executed. 3, the process proceeds to step S5 in FIG. 3, and the power to the loads 11a, 11b, 11c,... Supply is made. On the other hand, when the total load power is larger than the power that can be supplied, the shortage of power has not been solved yet, and the process proceeds to step S14.

  In step S14, the load control means 4 determines whether or not there is still a margin for reducing the duty ratio in the load driven by PWM. If there is still a margin for reducing the duty ratio, the process returns to step S11 to further reduce the duty ratio of the load to be PWM driven, and the subsequent processes are repeated. On the other hand, when there is no lowering of the duty ratio, that is, when the duty ratio has already been lowered to the minimum load level with high priority, in step S15, the control of the load control means 4 is performed. Thus, a process of stopping the operation from a load with a low priority is performed. Thereafter, the required power for the full load is reduced by stopping the operation of the load. As a result of the determination in step S13, if the required power for the full load is smaller than the suppliable power, the required power reduction routine is exited and the process shown in FIG. The process proceeds to step S5, and power is supplied to the remaining loads under the control of the load control means 4.

  As described above, in the power supply system of the present embodiment, under the control of the power supply control unit 5, the duty ratio of the load driven by PWM is set to one step until the total load required power becomes smaller than the suppliable power. I try to lower it one by one. Specifically, in the power supply system of the present embodiment, in the first stage, as shown in FIG. 5A, by reducing the duty ratio of the load to be PWM driven from 90% to 80%, for example, For example, the effective power supplied to the load can be reduced by about 10%. If the total load power still exceeds the suppliable power at this stage, then in the second stage, as shown in FIG. 5B, the duty ratio of the load is increased from 80% to 70%, for example. For example, the effective power supplied to the load can be reduced by about 20%. At this stage, if the total load power still exceeds the suppliable power, the duty ratio of the load is increased from 70% to 60%, for example, as shown in FIG. By reducing it, the effective power supplied to the load can be reduced by about 30%, for example. In the power supply system of the present embodiment, the duty ratio is changed as described above in order from the load with the lowest priority among the loads driven by PWM, so as to reduce the total load power requirement. And even if the above processing is performed for all loads that can reduce the duty ratio, the operation is stopped in order from the load with the lowest priority only when the required power of the entire load exceeds the power that can be supplied. I am doing so.

  Therefore, in the power supply system according to the present embodiment, even when the state where the power that can be supplied to the load is reduced and the total load power exceeds the power that can be supplied occurs, the operation of the load is avoided as much as possible. It is possible to reduce occupant discomfort associated with stopping the load operation. In addition, in the past, when the operation of a low priority load is stopped because the required load power exceeds the suppliable power, an occupant who feels uncomfortable increases the load priority. However, in the power supply system of the present embodiment, the operation stop of the load itself is avoided as much as possible, so that the operation is not forced on the occupant. The burden on passengers is also reduced. Furthermore, conventionally, processing such as estimating the passenger's preference such as the set temperature of the air conditioner device based on the operation history of the passenger and setting the priority of the load for supplying power has been performed. In this case, when the occupant changes, the power supply control according to the occupant's preference is not performed until the occupant's preference is estimated again and the load priority is changed. Although the problem of causing passenger discomfort has occurred, in the power supply system of the present embodiment, since the operation stop of the load is avoided as much as possible, such a situation does not occur.

  As described above in detail, in the power supply system of the present embodiment, when the suppliable power that can be supplied to the loads 11a, 11b, 11c,. Since the effective power supplied to the load is reduced by controlling the duty ratio of the load driven by PWM among 11b, 11c,..., The required load power exceeds the suppliable power. However, the shortage of the power that can be supplied can be compensated for by reducing the effective power supplied to the load, and the stop of the load operation can be avoided as much as possible. Therefore, according to the electric power supply system of this embodiment, the passenger | crew's discomfort accompanying the stop of operation | movement of load can be reduced.

  In the power supply system of the present embodiment, priorities are set for the loads 11a, 11b, 11c,..., And the load control means 4 performs PWM drive when the suppliable power is reduced. Since the duty ratio is lowered in order from the load with the lowest priority among the loads, the performance degradation with the reduction of the effective power is caused by the load with the lower priority, and the vehicle travels due to the reduction of the suppliable power Etc. can be minimized.

  Furthermore, in the power supply system of the present embodiment, a plurality of duty ratios that can be switched with respect to the load to be PWM driven are set in advance, and the load control means 4 performs PWM driving when the suppliable power decreases. Since the duty ratio of the load is lowered step by step, if the amount of power that can be supplied is small, the performance degradation of the load due to the reduction in effective power can be minimized, and The power shortage can be compensated without recognizing the performance degradation.

(Second Embodiment)
Next, a power supply system according to a second embodiment to which the present invention is applied will be described.

  The configuration of the power supply system of this embodiment is shown in FIG. In the power supply system of the present embodiment, the load control means 4 that performs power supply control for the loads 11a, 11b, 11c,... Is an intelligent power switch as a switching device for power supply control to the load that is PWM driven. (IPS: Intelligent Power Switch) 12a, 12b, 12c,. Since the intelligent power switches 12a, 12b, 12c,... Can detect the load current value, the load current sensor 3 in the first embodiment described above is unnecessary in the power supply system of the present embodiment. It is said that.

  Further, in the power supply system of the present embodiment, the functions of the power supply control means 5 and the generator control means 8 in the first embodiment described above are realized by the load control means 4, and the power supply control means 5 and The generator control means 8 is unnecessary. That is, in the power supply system of the present embodiment, the full load is required by performing a series of processes with the necessary power reduction routine shown in FIGS. 3 and 4 under the control of the load control unit 4. Until the power becomes smaller than the power that can be supplied, the duty ratio is decreased one step at a time from the low priority load among the PWM driven loads, and the duty ratio cannot be decreased for all the PWM driven loads. The operation is stopped from a low priority load for the first time.

  As described above, in the power supply system of this embodiment, the load control means 4 is provided with intelligent power switches 12a, 12b, 12c,. The functions of the power supply control means 5 and the generator control means 8 are provided so that a series of processing with the necessary power reduction routine shown in FIGS. 3 and 4 is executed as processing in the load control means 4. Therefore, while making the system configuration simpler than the first embodiment described above, the load operation is stopped even when the suppliable power is reduced, as in the first embodiment described above. It is possible to obtain the effect of avoiding as much as possible and reducing the discomfort of the occupant accompanying the stoppage of the load operation.

  Note that the power supply system described above is an application example of the present invention, and the present invention is not limited to the above example, and priority is given to the load as long as it does not depart from the technical idea of the present invention. Of course, various changes such as setting of the degree and setting of the duty ratio are possible.

It is a block diagram showing a schematic structure of a power supply system of a 1st embodiment to which the present invention is applied. It is a figure which shows the example of the priority set with respect to each load in the electric power supply system of the said 1st Embodiment. It is a flowchart which shows a series of control processing in the electric power supply system of the said 1st Embodiment. It is a flowchart which shows the procedure of the required power reduction routine performed in the electric power supply system of the said 1st Embodiment. FIG. 6 is a diagram showing a specific example of processing for decreasing the duty ratio of a load driven by PWM one step at a time in the power supply system of the first embodiment, and (a) shows a duty ratio of a load driven by PWM of 90%. (B) shows a state where the duty ratio of the load driven by PWM is reduced from 80% to 70%, and (c) shows a state where the duty ratio of the load driven by PWM is reduced from 70% to 60%. It is a figure which shows a mode that it fell to%. It is a block diagram which shows schematic structure of the electric power supply system of 2nd Embodiment to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Generator 2 Battery 3 Load current sensor 4 Load control means 5 Power supply control means 6 Battery current sensor 7 Battery temperature sensor 8 Generator control means 11a, 11b, 11c, ... Load 12a, 12b, 12c, ... Intelligent Power switch

Claims (5)

In a power supply system that supplies power to an onboard load,
Load control means for reducing the effective power supplied to the load by controlling the duty ratio of the load that is PWM driven among the loads when the suppliable power that can be supplied to the load decreases. A featured power supply system. A priority is set for the load to be driven by PWM,
2. The load control unit according to claim 1, wherein when the suppliable power that can be supplied to the load is reduced, the duty ratio is decreased in order from a load with a lower priority among the loads driven by the PWM. Power supply system. A plurality of duty ratios that can be switched are preset for the load to be driven by PWM,
3. The power supply system according to claim 1, wherein the load control unit decreases the duty ratio of the load driven by PWM one step at a time when the suppliable power that can be supplied to the load decreases. . The power supply system according to any one of claims 1 to 3, wherein the load control unit includes an intelligent power switch as a switching device for controlling power supply to the load driven by PWM. A method for controlling power supply to a load mounted on a vehicle,
When the suppliable power that can be supplied to the load decreases, the effective power supplied to the load is reduced by controlling the duty ratio of the load that is PWM-driven among the loads. Control method.

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