JP3452298B2 - Power supply system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply system, and can be applied to, for example, a power supply system that drives a load using a commercial power supply as a main power supply.

[0002]

2. Description of the Related Art Conventionally, as this type of power supply system, there is an uninterruptible power supply system 1 as shown in FIG. The uninterruptible power supply system drives the load 5 by introducing electric power from the commercial power supply 2 through the noise removal circuit 3 and the distribution circuit 4 and applying the electric power to the load 5. In addition to this, the uninterruptible power supply system 1 has an engine AC generator 7 that generates AC power using the fuel supplied from the fuel supply device 6.

The engine AC generator 7 is given a power necessary for starting power generation by the starter 9 and starts power generation.
Here, the starter 9 is driven when the power outage detection circuit 8 detects that there is a power outage, and the engine alternator 7 is driven.
To start. The voltage value generated by the engine AC generator 7 is detected by the voltage detector 10, and the voltage detector 1
0 switches the connection of the switch 11 from the commercial power source 2 side to the output side of the engine AC generator 7 when the detected voltage value becomes substantially equal to the voltage of the commercial power source 2.

The output current from the engine AC generator 7 that has passed through the switch 11 is an AC / DC converter (rectifier) 12
After being rectified by the DC / AC converter 13 and converted into an alternating current by the DC / AC converter 13, it is sent to the switch 14. The switch 14 is switched from the commercial power supply 2 side to the output side of the DC / AC converter 13 when the power failure detection circuit 8 detects a power failure.

Thus, in the uninterruptible power supply system 1, when the power is input from the commercial power supply 2, the switch 11 and the switch 14 are in the states as shown in the figure,
The power from the commercial power supply 2 is supplied to the load 5.

On the other hand, when electric power is no longer input from the commercial power supply 2 (that is, when a power failure occurs), the switch 14 is first switched to the output side of the DC / AC converter 13. Immediately after the electric power is not input from the commercial power supply 2, the desired voltage cannot be obtained from the engine AC generator 7, so the switch 11 is connected to the commercial power supply 2 side. Electric power is supplied from the storage battery 15. When a desired voltage is soon obtained from the engine AC generator 7, the switch 11 is switched to the engine AC generator 7 side so that the load 5 is supplied with the electric power generated by the engine AC generator 7. Become.

Thus, in the uninterruptible power supply system 1, including immediately after the power supply from the commercial power supply 2 is stopped (that is, including the period in which the engine AC generator 7 can generate an insufficient voltage). The load 5 can always be supplied with constant power.

[0008]

By the way, when the commercial power source is used in this way, the maximum current value that can be used with the electric power company that supplies the electric power is determined in advance by contract. . When a current larger than the current value determined by this contract is about to be introduced into the house, the breaker stops the supply of commercial power to the house.

If the power supply system 1 described above is used, even if the breaker (not shown) stops the supply of the commercial power supply 2 from the outside by using a current exceeding the contract current, The power failure state can be effectively avoided by the auxiliary power from the engine AC generator 7.

However, when the above-mentioned power supply system 1 is used, the breaker is cut off when the electric power exceeding the contract current is used, so that the input of the commercial power supply 2 is restored again. Has a problem in that the lever provided on the breaker must be manually returned from the "OFF" position to the "ON" position.

That is, the power supply system 1 described above
Is very effective when the supply of the commercial power supply 2 to the house itself is stopped due to a lightning strike or the like, but when the current consumption above the contract current is used, the breaker is cut off. Was not very effective because it takes time to restore the commercial power supply 2.

Here, when more electric power is required in the house, it is conceivable that the contract current value decided with the electric power company is simply set to a large value. However, in apartment houses, etc., the current value that can be introduced is limited to a certain value or less depending on the thickness of the power supply line introduced therein, so it is often not possible to make the contract current value more than a certain value. .

Further, in recent years, it has become difficult to add power plants, and the electric power of the commercial power source itself tends to be insufficient. Therefore, it is desired not to increase the contract current value in each house so much.

The present invention has been made in consideration of the above points, and proposes a power supply system capable of comfortably supplying a current exceeding the current value even when the current value that can be input from the outside is limited. Is what you are trying to do.

[0015]

A power supply system according to a first aspect of the present invention for solving the above-mentioned problems is provided with an external power supply 2 as shown in the basic configuration diagram of FIG.
Introduce current below the preset value as main power
Then, the main power is supplied to a single or multiple loads 5A, ..., 5X.
To a power supply system that is designed to supply and drive
In addition, the generator 50 for generating auxiliary power and the external power source 2
From a load or loads 5A, ..., 5X
The current consumption detecting means 51 for detecting the current consumption value
Setting current storing means 5 for storing the set current value determined in advance
2 and a single or multiple loads 5A, ..., 5X each load 5
A, ..., Load current that stores the load current value consumed by 5X
Stored in the flow storage means 56 and the set current storage means 52.
The set current value and the value stored in the load current storage means 56 are
At the same time as reading, the consumption current detection means from the set current value
51 minus the current consumption value detected by
Comparison using the load current value stored in the flow storage means 56
The value calculated by subtracting the current consumption value from the set current value is negative.
The load current value is less than or close to the load current value.
And the comparison calculation means 53 for detecting
Therefore, the value obtained by subtracting the current consumption value from the set current value is the load current.
It is detected that the value is below the value or close to the load current value.
When issued, the connection is switched and its load 5A, ...
…, A switch that gives 5X auxiliary power from the generator 50
And means 54 .

[0016]

[0017]

In the above arrangement, the comparison calculation means 53
Calculates the residual current value that can be introduced from the external power source (commercial power source) 2 at present by subtracting the current consumption value currently consumed in the house from the set current value (contract current value). Then, by comparing the remaining current value with the load current value stored in the load current storage means 56, if the load corresponding to the load current value is turned on, can this load be driven by the remaining current? Judge whether or not. If the value obtained by subtracting the current consumption value from the set current value is less than or equal to the load current value, it means that there is a possibility that the load cannot be driven due to the residual current. Auxiliary power from the generator 50 is applied to. Thus, no matter what load 5A, ..., 5X is turned on next time, auxiliary power is supplied from the external power source 2 at an appropriate timing so as not to introduce a current equal to or larger than the set current value.

According to a second aspect of the power supply system, the load current storage means 56 of the first aspect stores the maximum load current for each of the single or plural loads 5A, ..., 5X. To do so.

In the above configuration, the load current storage means 5
Since the maximum load current value of the loads 5A, ..., 5X is stored in 6, the comparison calculation means 53 assists based on the maximum load current value of the load currents that change according to the operation of the load. The timing of supplying power will be determined. As a result, even if the load is newly turned on, it becomes possible to supply the auxiliary power from the generator 50 at a safe timing such that the current not exceeding the set current value is never introduced from the external power supply 2.

In the power supply system according to a third aspect of the present invention, the timing of starting and stopping the power generation of the generator 50 or switching the connection by the switch means 54 has a hysteresis.

In the above configuration, the loads 5A, ..., 5
Repetition of starting and stopping the supply of auxiliary power by turning on and off X is suppressed, and the operation of the entire system becomes stable.

The power supply system according to claim 4 is, in addition to the configuration of claim 1, claim 2 or claim 3 , as shown in the basic configuration diagram of FIG. 1, the auxiliary power generated from the generator 50. A voltage detecting means 55 for detecting the voltage of electric power,
When the detected voltage value exceeds a predetermined value, the connection of the switch means 54 is switched to apply the auxiliary power from the generator 50 to the loads 5A, ..., 5X.

In the above configuration, the auxiliary power from the generator 50 is not supplied to the loads 5A, ..., 5X until the voltage detection means 55 detects a voltage equal to or higher than a predetermined value (rated voltage), and the load 5A ,. The auxiliary power is supplied only when a voltage higher than the value (rated voltage) is detected. As a result, since the auxiliary power from the generator 50 is not supplied during the period immediately after the start of power generation in which insufficient power can be generated,
A constant voltage is constantly supplied to the loads 5A, ..., 5X.

The power supply system according to a fifth aspect of the present invention, as shown in the basic configuration diagram of FIG.
In addition to the configuration of item 4, when the consumption current value detected by the consumption current detection means 51 becomes equal to or close to the set current value, a notification means 57 for notifying the user of this is provided. I was prepared.

In the above configuration, when the user turns on the new loads 5A, ..., 5X from the current state, the consumption current exceeds the set current value, and the auxiliary power from the generator 50 is supplied. It becomes possible to easily know that the notification will be made by the notification means 57. As a result, for example, when it is not desired to operate the generator 50, a new load 5
Stop turning on A, ..., 5X, or turn off another load 5A ,.
It becomes possible to turn on A, ..., 5X, and turn on / off the loads 5A, ..., 5X in consideration of the residual current value with respect to the set current value.

[0027]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2 in which parts corresponding to those in FIG. 6 are designated by the same reference numerals, 20 indicates the power supply system according to the embodiment as a whole, and the power from the commercial power supply 2 as an external power supply is supplied to the noise removing circuit 3 And a load 5 such as an air conditioner or a television device via the distributor 4A. A load (not shown) is also connected to the latter stage of the distributors 4B and 4C. The load 5 is turned on / off according to the operation of the on / off switch 27a of the remote controller 27.

The power supply system 20 has an engine AC generator 7 and appropriately supplies the auxiliary power generated by the engine AC generator 7 to the load 5. The power supply system 20 also has a power supply selector 22. The power supply selector 22 has a consumption current detection function, and is based on the voltage value detected by the current detection coil 21 provided on the power supply line connecting the commercial power supply 2 and the loads 5 ,. Calculate the current consumption value supplied from the power supply 2 to the loads 5, ....

Further, the power source selector 22 has a comparison calculation function, and displays the current consumption value detected based on the voltage value from the current detection coil 21 and the contract current value previously determined by the contract with the electric power company. When a calculation for comparison is performed and the current consumption value approaches the contract current value, the power generation operation of the engine AC generator 7 is started and the commercial power supply 2 is applied to the load 5.
The auxiliary power from the engine AC generator 7 is supplied in place of the main power from.

As a result, in the power supply system 20, before the current consumption consumed by the loads 5, ... Is larger than the contract current value and the breaker (not shown) falls, the engine AC generator 7 is added to the load 5. It is designed to be able to supply auxiliary power from.

In practice, the power source selector 22 is the start switch 2
When 2a is turned on, the operation is started by the electric power from the commercial power supply 2, and the current consumption value currently supplied from the commercial power supply 2 to the loads 5, ... Based on the voltage value output from the current detection coil 21. To detect. Then, when the current consumption value becomes a value close to the contract current value, the operation control switch 9a of the starter 9 is turned on to start the power generation of the engine AC generator 7, and the engine AC generator 7 A connection switch 2 provided between the engine AC generator 7 and a voltage detector 24 that detects the output voltage value of the engine AC generator 7.
3 is turned on, and the changeover switch 26 is set to the commercial power source 2
The connection point a on the side is switched to the connection point b on the engine AC generator 7 side.

Here, the power source selector 22 is constructed as shown in FIG. The power supply selector 22 uses the voltage value obtained by the current detection coil 21 as a preamplifier 30 and a rectifier 3.
1, the analog-digital converter (A / D) 32 and the interface circuit 33 are sequentially input to the CPU (central processing unit) 36.

Further, the power source selector 22 has a contract current setting unit 34 having a button switch configuration in which numeric keys from “0” to “9” are arranged, and the contract current setting unit 34.
The contract current value input by the user using is stored in the memory 37. Further, the power supply selector 22 is provided with a load current setting unit 35 having the same configuration as the contract current setting unit 34, and the load current value input by the user using the load current setting unit 35 is stored in the memory 37. Is stored.

In this embodiment, the maximum load current value of the load currents of the load 5 is input from the load current setting section 35 by the user. For example, if the load 5 is an air conditioner, its load current value will change at any time depending on the set temperature and the surrounding environmental temperature. However, the maximum current value of the load current value consumed by the air conditioner is stored in advance in a memory. Store in 37.

The power source selector 22 converts the detected voltage value from the voltage detector 24 into an analog-digital converter (A / D).
CP via 40 and interface (I / F) 33
Input in U36.

The CPU 36 has the contract current value and the load current value stored in the memory 37 as the set current storage means and the load current storage means, and the analog-digital converter 3.
The comparison calculation to be described later is performed using the current consumption value obtained from the output of 2 and the output contact drive circuit 38 is controlled according to the comparison calculation result, so that the on / off switch 9a, the connection switch 23, the changeover switch 25, and By connecting the change-over switch 26 to a predetermined connection position and controlling the display drive circuit 39, the display 22b blinks.

Here, the power source selection process by the CPU 36 is
This will be described with reference to FIGS. 4 and 5. When the CPU 36 starts the power source selection processing procedure in step SP0, it determines in step SP1 whether or not the activation switch 22a is in the ON state,
If it is in the off state, the process proceeds to step SP2 to end the power source selection processing procedure.

On the other hand, when it is determined in step SP1 that the activation switch 22a is in the ON state, step SP
3, the current consumption value A currently supplied from the commercial power source 2 to the loads 5A, ... Is measured based on the output of the analog-digital converter 32.

Next, the CPU 36 fetches the contract current setting value B from the memory 37 in step SP4, and multiplies the contract current setting value B by 0.9 in the subsequent step SP5. In step SP6, the CPU 36 determines whether or not the current consumption value A measured in step SP3 is equal to or greater than the contract current setting value B multiplied by 0.9, that is, the value C.

If the current consumption value A measured in step SP3 is greater than or equal to the contract current setting value B multiplied by 0.9, the process proceeds to step SP7.
By blinking, the user is informed that the current consumption value is close to the contract current setting value, in other words, if the switch of load 5 is turned on, the consumption current value is likely to exceed the contract current setting value. Inform.

After the end of step SP7 or when a negative result is obtained in step SP6, the CPU 36 proceeds to step SP8 and fetches the load current set value D from the memory 37. Next, the CPU 36 proceeds to step SP9
A value E is obtained by subtracting the measured consumption current value A from the value C obtained by multiplying the contract current setting value B by 0.9.

In step SP10, it is judged whether or not the value E obtained in step SP9 is less than or equal to the load current setting value D. If it is less than or equal to the value D, the process proceeds to step SP11 and is greater than the value D. In that case, it moves to step SP14.

Here, the positive result obtained in step SP10 means that the residual current value that can be introduced from the commercial power source 2 is in a small state, and if the load 5 is turned on, a breaker (not shown) is shown. ) Is in a state of falling. And in such a case, the CPU 3
In step SP11, the on / off switch 9a of the starting device 9 is turned on to start the power generation operation of the engine AC generator 7, and in the following step SP12, the connection of the changeover switch 26 is switched to the connection point b to control the load. Preparation for supplying auxiliary power from the engine AC generator 7 to the motor 5 is made.

On the other hand, the negative result obtained in step SP10 means that the current consumption value is within the contract current value even if the switch of the load 5 is turned on. In such a case, since it is not necessary to supply auxiliary power from the engine AC generator 7, the ON / OFF switch 9a of the starting device 9 is turned off in step SP14 to turn off the engine AC generator 7.
In step SP15, the changeover switch 26 is connected to the connection point a to prepare for supplying the main power from the commercial power supply 2 to the load 5.

After the processing of step SP12 or step SP15, the CPU 36 moves to step SP13 and detects whether the detected voltage value from the voltage detector 24 is 90 [V] or more, and the voltage is 90 [V] or more. When this happens, this means that the engine AC generator 7 has generated sufficient electric power to operate the load 5 stably. Therefore, the process proceeds to step SP16 and the changeover switch 25 is set to the engine AC generator 7 side. Switch to load 5 and engine AC generator 7
Supply auxiliary power from.

On the other hand, if a negative result is obtained in step SP13, it means that the engine AC generator 7 has not yet generated sufficient electric power to stably operate the load 5, or the engine AC generator. Since this means that the operation of 7 has not been started, the process moves to step SP17 and the changeover switch 25 is switched to the commercial power source 2 side to supply the main power from the commercial power source 2 to the load 5. And CPU
36 returns to step SP1 after the processing of step SP16 or step SP17.

In the above configuration, the power supply system 2
0 detects the current consumption value A currently supplied from the external power supply 2 to the load (not shown) in the system before the switch 5a of the load 5 is turned on. Then, by subtracting the current consumption value A from the contract current value B, the current commercial power supply 2
The remaining current value that can be introduced is obtained from (from this embodiment, the remaining current value is slightly calculated by multiplying the contract current value B by 0.9 to give a slight margin).

Next, the power supply system 20 compares this residual current value with the load current value of the load 5 stored in the memory 37, so that if the load 5 is turned on, the load 5 remains. It is judged whether or not the current can be driven. If the residual current value is less than or equal to the load current value of the load 5, it may not be possible to drive the load 5 due to the residual current.
Is supplied with auxiliary power from the engine AC generator 7.

As a result, even if the load 5 is turned on, if the current exceeding the contract current value is introduced from the commercial power source 2, the load AC is not the power from the commercial power source 2 but the engine AC power generation. The electric power from the machine 7 is supplied, and the breaker breaks the commercial power supply 2 in advance, for example.

Since the load current value of the load 5 stored in the memory 37 is the maximum load current value among the load currents that change according to the operation of the load 5, even if the load 5 is newly turned on, It is possible to switch from the commercial power supply 2 to the engine AC generator 7 at a safe timing so that the commercial power supply 2 never introduces a current equal to or more than the contract current value to the commercial power supply 5.

Further, in the power supply system 20, the auxiliary electric power from the engine AC generator 7 is not supplied to the load 5 until the voltage detector 24 detects a voltage higher than the rated voltage (90 [V]). The auxiliary power is supplied only when a voltage higher than the rated voltage is detected. As a result, the auxiliary power from the engine alternating-current generator 7 is not supplied during a period immediately after the start of power generation in which insufficient power can be generated, so that a constant voltage is always supplied to the load 5.

In the power supply system 20, the CPU 3
When it is determined by 6 that the engine AC generator 7 should be stopped, the CPU 36 controls the connection switch 23 to be turned off. As a result, due to inertia, it is instantly 0
It is possible to completely cut off the output of the engine AC generator 7 that does not reach [V].

By the way, the above-mentioned load current set value D and the value D'which is obtained by increasing or decreasing the load current set value D by a certain numerical value are 2
A comparison calculation process by the CPU 36 using two values D and D ', or two values B and B'of the above-mentioned contract setting current value B and the contract setting current value B increased or decreased by a certain numerical value. By performing (step SP10), it becomes possible to add hysteresis to the timing of starting and stopping the power generation of the engine AC generator 7 or switching the connection by the changeover switch 26. As a result, it is possible to suppress the repetition of starting and stopping the supply of auxiliary power due to the turning on and off of the load, and to stabilize the operation of the entire system.

In the above-mentioned embodiment, one load 5 in the power supply system 20 is provided for simplification of description.
Although only the supply of the auxiliary power to the above has been described, the auxiliary power may be supplied to other loads in the system by the same method. That is, the load current value consumed by each load is stored in the memory 37, and switch means such as the changeover switch 25 and the changeover switch 26 are provided for each load, and the CP as the comparison calculation means is provided.
The U36 may execute the power source selection processing procedure as described above with reference to FIGS. 4 and 5 for each load to selectively supply the power of the commercial power source 2 or the engine AC generator 7 to each load. Good.

Further, in the above-described embodiment, when the current consumption value detected by the current consumption detecting means becomes equal to the set current value (contract set current value) or becomes close to the set current value, the user is informed. Although the case has been described in which the indicator 22b is provided as the notifying means for notifying this and the indicator 22b is blinked, the notifying means is not limited to this, and a buzzer may be sounded, for example.

[0057]

As described above, according to the first aspect of the present invention, the generator for generating the auxiliary power and the single or the external power source are used.
Is a switch that detects the current consumption value that is being supplied to multiple loads.
Stores current consumption detection means and preset current value
Setting current storage means and each load of single or multiple loads
Load current storage means for storing the consumed load current value, and
Set current value and load current stored in constant current storage means
The value stored in the means is read and the set current
The consumption current value detected by the consumption current detection means from the value
The subtracted value and the load current value stored in the load current storage means
Performs a comparison calculation using and to calculate the consumption current value from the set current value.
Is less than or equal to the load current value or close to the load current value.
Comparison operation means for detecting that a new value is reached, and comparison operation
By the means, the value obtained by subtracting the current consumption value from the set current value is negative.
The load current value is less than or close to the load current value.
And are detected, the connection is switched and the load is activated.
Switch means for supplying auxiliary power from the electric machine.
By doing so, what kind of load will be turned on next?
Even if the current exceeds the set current value from the external power supply,
Power supply that can supply auxiliary power at appropriate timing
A supply system can be realized .

[0058]

According to the invention described in claim 2,
Since the maximum load current for each load is stored in the load current storage means of item 1 , a certain load is newly turned on in addition to the effect of the invention of claim 2. Even if it is done, it is possible to realize the power supply system capable of supplying the auxiliary power from the generator at the safest timing such that the current more than the set current value is never introduced from the external power supply.

According to the third aspect of the invention, hysteresis is provided at the timing of starting and stopping the power generation of the generator or switching the connection by the switch means. In addition to the effects of the present invention, it is possible to realize a power supply system that can stabilize the operation of the system by suppressing the repetition of starting and stopping the supply of auxiliary power by turning the load on and off.

According to the invention described in claim 4, voltage detecting means for detecting the voltage of the auxiliary electric power generated from the generator is provided, and when the detected voltage value exceeds a predetermined value, the switch means is connected. By supplying the auxiliary electric power from the generator to the load by switching the above-mentioned, in addition to the effects of the invention of claims 1 to 4, insufficient electric power is generated by the generator, such as immediately after the start of power generation. Since the auxiliary power from the generator is not supplied during the period when it is not possible, a constant voltage is always supplied to the load, and it is possible to realize a power supply system that can suppress the voltage fluctuation of the power supply to the load. .

Further, according to the invention described in claim 5, when the consumption current value detected by the consumption current detecting means becomes equal to or close to the set current value,
By providing the notification means for notifying the user of this, in addition to the effects of claims 1 to 5, the user can switch the load in consideration of the residual current value with respect to the set current value. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a power supply system according to the present invention.

FIG. 2 is a connection diagram showing an overall configuration of a power supply system according to an embodiment.

FIG. 3 is a block diagram showing a configuration of a power supply selector.

FIG. 4 is a flowchart showing a power supply selection processing procedure.

FIG. 5 is a flowchart showing a power supply selection processing procedure.

FIG. 6 is a connection diagram showing a configuration of a conventional uninterruptible power supply system.

[Explanation of symbols]

2 Commercial power supply (external power supply) 5, 5A to 5B load 7 Engine AC generator (generator) 20 Power supply system 22 Power supply selector 22b Display (notification means) 24 Voltage detector (voltage detection means) 25 Changeover switch ( Switch means) 26 Changeover switch (switch means) 36 CPU (comparison operation means) 37 Memory (set current storage means, load current storage means)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-280142 (JP, A) JP-A-7-198752 (JP, A) Actual development Sho-61-176935 (JP, U) (58) Investigation Field (Int.Cl. ⁷ , DB name) H02J 9/08

Claims (5)

(57) [Claims] 1. A power supply system configured to introduce a current of a predetermined value or less as a main power from an external power source and supply the main power to a load or loads to drive the auxiliary power. And a generator for generating current, a consumption current detecting means for detecting a consumption current value supplied to the one or more loads from the external power source, and a set current storage means for storing the predetermined set current value. A load current storage unit that stores a load current value consumed by each load of the single or the plurality of loads; and a set current value stored in the set current storage unit and a value stored in the load current storage unit. And a load current value stored in the load current storage means and a comparison value using a value obtained by subtracting the consumption current value detected by the consumption current detection means from the set current value. It was carried out,
From the set current value, the comparison operation means detects that the value obtained by subtracting the consumption current value from the set current value is equal to or less than the load current value or close to the load current value. Switching means for switching the connection when it is detected that the value obtained by subtracting the consumption current value is equal to or less than the load current value or close to the load current value, and supplies the load with auxiliary power from the generator. A power supply system comprising: 2. The power supply system according to claim 1, wherein the load current storage means stores a maximum load current for each of the one or more loads. 3. The power supply according to claim 1 or 2, wherein a timing is provided to start and stop power generation of the generator or to switch connection by the switch means. system. 4. A voltage detecting means for detecting a voltage of the auxiliary electric power generated from the generator, and when the detected voltage value exceeds a predetermined value, the connection of the switch means is switched to the load. The power supply system according to claim 1, 2 or 3, wherein auxiliary power from a generator is applied. 5. When the consumed current value detected by the consumed current detecting means becomes equal to the set current value or becomes close to the set current value, a notifying means for notifying the user of this is provided. The power supply system according to claim 1, claim 2, claim 3, or claim 4.