JP3523017B2 - Power supply - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct current (AC) system for exchanging direct current (DC) to AC, such as UPS (Uninterruptible Power Supply).
The present invention relates to a power supply including an AC power conversion circuit and a power supply device that switches the power supply and a commercial power supply to supply power to a load.

[0002]

2. Description of the Related Art FIG. 16 shows a conventional example of the present invention.
For example, it is an “inverter device having a power supply system switching circuit” disclosed in Japanese Patent Laid-Open No. 4-281343. In the figure, 1 is a capacitor for stabilizing a DC voltage, 2 is an inverter for converting a DC voltage into an AC voltage, 3 is a reactor, 4 is a capacitor. Constitutes an inverter circuit. Further, 6 is a load, 7 is a commercial power source, 5 is a system switching circuit, and a bypass switch 5a for connecting / disconnecting the commercial power source 7 and the load 6, and an inverter switch for connecting / disconnecting the inverter circuit and the load 6. 5b and. The bypass switch 5a and the inverter switch 5b are switches that open and close electrically (for example, thyristor, transistor, etc.), switches that open and close mechanically (for example, contactor, motor breaker, etc.), or switches in which they are connected in parallel. Composed of.

Further, 20 is a current sensor for detecting the output current of the inverter 2, 21 is a voltage sensor for detecting the inverter voltage obtained by filtering the output of the inverter circuit,
A voltage sensor 22 detects the voltage of the commercial power supply 7.

Further, the 100's represent control circuit parts of the inverter circuit, 100 is a switching signal generator for outputting an ON / OFF signal to the system switching circuit 5 and a switch 104 described later, and 102 is an output of the voltage sensor 22. The phase detector for detecting the phase information of the system voltage from 101, the reference sine wave generator 101 for outputting the sine wave voltage command of the inverter 2 according to the phase information, and the reference numeral 103 for the inverter current when the inverter current exceeds the overcurrent value. An overcurrent drooping circuit that outputs a proportional drooping voltage amount, and 104 is a switching signal generator 100.
The control switch 105 opens and closes according to the output of the control switch 105, and the control switch 1 receives the output of the reference sine wave generator 101 from the sine wave command.
The subtractor subtracts the output of 04, the subtractor 106 subtracts the inverter voltage detected by the voltage sensor 21 from the inverter voltage command which is the output of the subtractor 105, and 107 is the command which is the output of the subtractor 105 and the field back A voltage control circuit that operates so as to eliminate the voltage deviation is a switching signal generator 108 that generates a switching signal for the inverter 2 from the corrected inverter voltage command output from the voltage control circuit 107.

FIG. 17 is an output signal timing chart of the switching signal generator 100 when switching from the inverter 2 to the commercial power supply 7.

Next, the operation will be described with reference to the timing chart of FIG. The system switching circuit 5 uses the inverter switch 5b and the bypass switch 5 when the inverter circuit fails or maintenance is performed on the inverter circuit.
It is a circuit that switches from the inverter 2 to the commercial power supply 7 and from the commercial power supply 7 to the inverter 2 while both a and a are in the ON state (hereinafter, referred to as a wrap state). Here, for example, when switching from the inverter to the commercial power source, the bypass switch 5a is turned on from the on state of the inverter switch 5b, and after the lap period is provided, the inverter switch 5b is turned on.
Turn off. The control switch 104 is on during this lap period. The lap period is 0.5 sec at the longest.
It is set to a degree.

If the voltage difference between the inverter 2 and the commercial voltage 7 is 2% during this lap period, if the reactor 3 of the inverter is 2%, 100% of the current flows between the commercial power source 7 and the inverter 2. If the load current to be supplied to the load 6 is added (this current will be referred to as a cross current hereafter), the allowable current of the inverter circuit will be exceeded.
Therefore, during the lap period, the inverter current, which is the sum of the cross current and the load current, is detected, and when these rated load current values are exceeded, the overcurrent drooping circuit 103 outputs a voltage adjustment amount proportional to the current amount and outputs the inverter voltage command. Subtract from. By this operation, when a current of a predetermined value or more flows out from the inverter 2, a positive voltage adjustment amount proportional to the current is output, and the subtractor 105 subtracts the positive voltage correction amount from the sine wave voltage command to reduce the inverter voltage command. The voltage control circuit 107 operates according to the command so that the voltage difference between the commercial voltage and the inverter voltage is reduced.

[0008]

Since the conventional inverter device having the system switching circuit is constructed as described above, it is impossible to distinguish between the load current and the cross current. At that moment, a cross current of about the rated current will flow, and the same distortion will occur in the output voltage as when the load suddenly changed. Further, since the limiter characteristic of the overcurrent drooping circuit 103 operates near the peak of the inverter current, the inverter output voltage waveform is partially increased or decreased, the output voltage waveform is distorted, and the output voltage is difficult to stabilize. At this time, if the commercial power supply system is weak, the load voltage is similarly distorted, and a cross current may occur between the commercial power supply 7 and the inverter 2 near the boundary of the overcurrent, and the load voltage may vibrate.

The present invention has been made to solve the above problems, and eliminates the cross current that flows when the commercial power supply and the inverter circuit are in a wrap state, and further smoothly transfers the load between the inverter circuit and the commercial power supply. The purpose is to supply a stable voltage to the load.

[0010]

A power supply device according to a first aspect of the present invention controls an output voltage thereof so as to follow a voltage command.
One power source, a second power source independent of the first power source, the above
A first switch, inserted between the first power source and the load,
Note Second opening and closing inserted between the second power source and the load
Switch and the above-mentioned first and second switches for the same period of time.
Power is supplied to the above load after a lap period in which the circuit is closed.
Supply the power between the first power source and the second power source.
A power supply switching means for switching is provided, and further, the current of the load is
Load current detecting means for detecting the output current of the first power source
Output current detection means for detecting current, or both current detection means
The subtractor that calculates the deviation from the
By correcting the voltage command so that
Suppresses the cross current that flows between the above two power sources during the up period
In a power supply device having a cross current control means, the load current
Between the detection means and the subtractor, from the load current detection means
Load current for switching between load current detection output and zero output
Switching means is provided to switch from the second power source to the first power source.
At the time of replacement, check the timing of the closing operation of the first switch.
Output the output of the load current switching means at the relevant timing.
Switching from the zero output to the load current detection output,
When switching from the second power supply to the second switch,
Detects the timing at which the
Output the load current switching means above the load current detection output.
The output is switched to zero output .

[0011] The power supply device according to claim 2, claim
1, the load current detection output of the load current switching means
The degree of change over time between switching between zero and zero output
It is equipped with a load transfer means .

[0012] The power supply device according to claim 3, claim
2, load current detection in the load transfer means
At the timing of completion of switching from output to zero output, the first opening
Open the closed circuit and switch from the zero output to the load current detection output.
The second switch will be opened at the timing of completion of switching
It is a scam .

A power supply device according to a fourth aspect of the present invention complies with a voltage command.
Multiple power supplies whose output voltage is controlled to
A switch inserted between each of the sources and the load, and
Close by opening one of the switches and opening the other.
Switch off each power source to supply power to the load
In the power supply device equipped with the switching means, the current of the load is detected.
Detecting load current, output current of each power supply
Output current detection means, from the switching commands to the above switches
Input the operation information of each power source,
The shared current that should be output from each power supply based on the detected load current value
Shared current detection means for detecting
A subtracter that calculates the deviation between the detected current value and the shared current
Modify the above voltage command so that the output of the subtractor of becomes zero.
The cross current control that suppresses the cross current that flows between the above power supplies.
It is equipped with means .

[0014] The power supply device according to claim 5, claim
4, the device capacities of the respective power supplies are the same as each other.
In this case, the shared current detection means uses the operation information of each power source described above.
Enter the number of operating power supplies in the operating status, and detect the load current.
Calculate the shared current by dividing
It is obtained by way.

[0015] The power supply device according to claim 6, claim
4, the shared current detecting means is the operating information of each power source.
From the report, the total device capacity of all power supplies
The ratio of the device capacity of the power supply to the sum (shared load ratio)
A selector that outputs and outputs zero when not in operation.
Adder that calculates the output sum of each selector, each of the above select
A divider that divides the output of the data by the output of the adder above, and
The output of each divider is multiplied by the load current detection value to obtain the power
Is provided with a multiplier that creates a shared current to be output by .

[0016] The power supply device according to claim 7, claim
4 to 6, any of its respective power sources
The shared current that each power supply should output due to changes in the operating state of
Change, the degree of change in the above shared current with time is relaxed.
And a load transfer means for sending the data to the subtractor .

[0017] The power supply device according to claim 8, claim
Follow the voltage command in any of 1 to 7
Power supply to control its output voltage so that the DC voltage is AC
The inverter that converts to voltage and the output of this inverter
L consisting of a reactor and a capacitor connected to the power end
A C filter is provided .

[0018] The power supply device according to claim 9, claim
8, the output current detection means of the power source is an inverter
Inverter current sensor for detecting the current at the output end of the inverter, L
Capacitor voltage to detect the voltage of C filter capacitor
Pressure sensor, capacity of the above capacitor and voltage of the above capacitor
Calculate the current flowing in the above capacitor from the detected value.
Capacitor current predictor and inverter current detection value
The output current of the above power supply is calculated from the predicted value of the capacitor current.
It is equipped with a subtractor for calculating .

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. 1 is a diagram showing a configuration of an inverter device according to a first embodiment of the present invention. In the figure, 1-7, 20-2
2, 101, 102, 104, and 106 to 108 are equivalent to the conventional ones, and thus their individual explanations are omitted. Reference numeral 23 is a current sensor as an output current detecting means for detecting the output current of the inverter circuit which is the first power source, 24 is a current sensor as a load current detecting means for detecting the current of the load 6,
109 is a switching signal generator that outputs an on / off command to the system switching circuit 5 and the control switch 104, 111 is a subtractor that calculates the deviation between the output from the current sensor 24 and the output from the current sensor 23, and 112 is a subtractor A cross current control circuit as a cross current control means for sending an output (amount of voltage adjustment) for correcting the voltage command from the reference sine wave generator 101 so that the output of 111 becomes zero, to the adder 105 via the control switch 104, For example, it is composed of a proportional control element.

Next, the operation will be described. FIG. 2 shows the lap period and ON / OFF of each switch 5a, 5b, 104.
In the timing chart showing the operation, the upper stage shows the case of switching from the inverter to the bypass, and the lower stage shows the case of switching from the bypass to the inverter. Here, the control switch 104 is turned on / off in synchronization with the inverter switch 5b.
Perform FF operation. First, the operation when switching from the inverter to the bypass, that is, the commercial power supply 7 will be described.
While the inverter 2 is operating independently, the inverter switch 5b
And the control switch 104 is ON, the bypass switch 5
Since a is OFF, the output from the current sensor 23 and the output from the current sensor 24 are equal, and the voltage adjustment amount from the cross current control circuit 112 is zero. Here, when an ON command is output from the switching signal generator 109 to the bypass switch 5a, the bypass switch 5a is turned on and the lap period is started.

In the lap state, when a cross current, that is, a deviation between the output from the current sensor 23 and the output from the current sensor 24 occurs, the subtractor 111 outputs this deviation to the cross current control circuit 112. In the cross current control circuit 112, a positive voltage adjustment amount is controlled so as to prevent the current from flowing by increasing the voltage of the inverter 2 when a current is flowing from the bypass so that the deviation (cross current) becomes zero. 10
4 is sent to the adder 105, and conversely, when a current is flowing from the bypass, a negative voltage adjustment amount is sent to the adder 105 and the voltage command to the inverter 2 is corrected. Inverter 2 based on the corrected voltage command
By operating, the output voltage and the voltage of the commercial power supply 7 become equal and the cross current becomes zero.

In this case, since the cross current control circuit 112 is composed of a proportional control element, the correction operation of the voltage command described above is quickly performed. After that, when a predetermined lap period elapses, an OFF command is output from the switching signal generator 109 to the inverter switch 5b and the control switch 104, the lap period ends, and the switching of the commercial power source 7 to the independent operation is completed. .

Next, the operation when switching from the bypass to the inverter will be described. While the commercial power source 7 is operating independently, the inverter switch 5b and the control switch 10
4 is OFF and the bypass switch 5a is ON, the output from the current sensor 24 is the same as that of the subtractor 11
Although the deviation output of 1 is input to the cross current control circuit 112, since the control switch 104 is in the OFF state, the voltage adjustment amount output from the cross current control circuit 112 is sent to the adder 105. There is no such thing.

Here, when an ON command is output from the switching signal generator 109 to the inverter switch 5b and the control switch 104, both switches 5b and 104 are turned on and the lap period is started. When a cross current occurs in the lap state, the cross current control circuit 112 outputs the voltage adjustment amount based on the deviation output from the subtractor 111 due to the cross current. In this case, since the control switch 104 is ON, the voltage adjustment amount is sent to the adder 105 as it is, and the voltage command is promptly corrected to suppress the cross current.

After that, when the lap period elapses, an OFF command is output from the switching signal generator 109 to the bypass switch 5a, the lap period ends, and the switching of the inverter 2 to the independent operation is completed.

As described above, in the first embodiment, the output voltage of the inverter circuit is controlled to be the same as the voltage of the commercial power source 7 during the lap period, and stable operation without cross current or vibration phenomenon between both power sources. The switched power supply is achieved.

Embodiment 2. 3 is a diagram showing a configuration of an inverter device according to a second embodiment of the present invention, which is generally equivalent to the circuit of FIG. 1, but is different only in the method of detecting the output current of the inverter circuit. Therefore, hereinafter, this part will be mainly described. That is,
Here, the current sensor 23 (FIG. 1) that directly detects the output current of the inverter circuit is not specially provided, and the output terminal current of the inverter 2 that is always installed for protection of the switching element that constitutes the inverter 2 is detected. The output current of the inverter circuit is obtained using the current sensor 20.

In FIG. 3, reference numeral 113 indicates the voltage Vc of the capacitor 4 which is the output from the voltage sensor 21 and the capacitor 4
It is a capacitor current predictor that calculates the current ic of the capacitor 4 from the capacitance C of ic = C · (dV
c / dt) 114 is a subtracter that calculates the output current of the inverter circuit by subtracting the capacitor current obtained by the capacitor current predictor 113 from the inverter current detected by the current sensor 20, and the output thereof is the subtracter 1
11 is sent.

As described above, in the second embodiment, the output current of the inverter circuit can be obtained without providing the dedicated current sensor 23, so that there is an advantage that the apparatus is simple and inexpensive. In each of the subsequent embodiments, the method of FIG. 3 is adopted as far as the detection means of the inverter circuit output current is concerned, but the method of directly obtaining from the current sensor 23 shown in FIG. It goes without saying that you can do it.

Embodiment 3. In the first and second embodiments, the switching signal generator 10 is used.
ON from 9 to inverter switch 5b of system switching circuit 5
At the same time when the command is output, the ON command is also output to the control switch 104. That is, the operations of both switches 5b and 104 are synchronized. However, when a mechanical switch such as a contactor is used as the inverter switch 5b,
It takes several cycles from the receipt of the ON command until the circuit is actually closed, and since the time is not constant, it is conceivable that the timings at which both switches 5b and 104 are closed do not always match.

For example, when the control switch 104 is closed first, the cross current control circuit 112 receives a large deviation output from the subtractor 111 and sends a large voltage adjustment amount to the adder 105 via the control switch 104. As a result, the inverter 2
Tries to increase the output voltage and pass the load current, but
Since the inverter switch 5b is not closed, the capacitor 4 is charged and its voltage becomes excessive. When the inverter switch 5b is inserted in this state, a large voltage difference is generated between the commercial power supply 7 and a large cross current flows and the output voltage also fluctuates.

In the third embodiment, the above-mentioned problem is solved by detecting the actual closing timing of the system switching circuit 5, and FIG. 4 is a diagram showing the configuration of the inverter device. In FIG. 4, the switching signal generator 115 turns ON / OF the bypass switch 5a and the inverter switch 5b.
While sending the F command, the switch 5a, 5b inputs a closing detection signal that operates at the timing when the switches actually close, and based on this, it confirms that the lap state is actually entered and outputs a load current switching signal. . 116 is a subtracter 11 based on the load current switching signal from the switching signal generator 115.
It is a switching device as load current switching means for switching the signal to 1.

Next, the operation will be described with reference to the timing chart of FIG. The upper part of FIG. 5 shows the switching from the inverter to the bypass, and the ON command is sent from the switching signal generator 115 to the bypass switch 5a to start the lap period.
Therefore, the switch 116 continues to send the load current detection value from the current sensor 24 to the subtractor 111. Therefore, the control operation of the inverter operation is substantially maintained. Then, when the bypass switch 5a is actually closed (in FIG. 5, the bypass switch 5a is closed at a timing substantially in the center of the period displayed as the lap period).
Upon receiving the closed circuit detection signal, the load current switching signal changes to the "L" level, and the switching device 116 sends a zero output to the subtractor 111. As a result, the inverter 2 promptly reduces its output to zero, and the commercial power supply 7 shifts to the independent operation.

The lower part of FIG. 5 shows the switching from the bypass to the inverter. In this case, at the timing when the inverter switch 5b is actually closed after the ON command is sent from the switching signal generator 115 to the inverter switch 5b,
Upon receiving the closed circuit detection signal, the load current switching signal changes from "L" level to "H" level, and in response to this, the switch 1
16 sends the load current detection value from the current sensor 24 to the subtractor 111 instead of the zero output so far. Therefore, also in this case, a smooth operation switching characteristic from the commercial power source 7 to the inverter 2 can be obtained without causing the above-mentioned problems.

Fourth Embodiment 6 is a diagram showing a configuration of an inverter device according to a fourth embodiment of the present invention. Hereinafter, the description will be centered on the portions different from the above-described example of the embodiment, and the description of the common portions will be appropriately omitted. Here, for example, even if the commercial power supply 7 is weak, load transfer is performed so that smooth power supply switching can be performed without fluctuations in voltage so that the degree of temporal change of the signal output sent to the subtractor 111 is eased during switching. A load transfer circuit 117 is provided as a means.

FIG. 7 shows the internal structure of the load transfer circuit 117. Reference numeral 200 denotes a change amount easing device, which is a load current switching signal output from the switching signal generator 115 ("1" at the "H" level). When it is at "" or "L" level, "0") is input, and the signal is output in response to the degree of temporal change of the input signal by being configured by, for example, a primary filter circuit. Multiplier 201 multiplies the load current detection value from current sensor 24 by the signal from change amount reducer 200 and sends the output signal to subtractor 111.

FIG. 8 is a timing chart showing the operation at the time of switching. Although the overall operation is the same as that of the third embodiment, a description thereof will be omitted. However, as shown in FIG. 8, the output of the load transfer circuit 117 sent to the subtractor 111 is output by the change amount reducer 200. Changes more gently than in the case of FIG. 5, and as a result, the power supply switching operation is made smoother, and fluctuations in the voltage and current of each part during switching are suppressed.

Embodiment 5. FIG. 9 shows the configuration of an inverter device according to a fifth embodiment of the present invention. The load transfer circuit 11 shown in FIG.
By providing a load transfer circuit 117a that is a modification of No. 7, the lap period is completed in the minimum necessary time. That is, for example, from the commercial power source 7 to the inverter 2
When the power supply is switched to, if the voltage of the commercial power supply 7 fluctuates or a momentary voltage drop occurs during the lap period, the inverter voltage fluctuates so as not to flow the accompanying cross current. Therefore, the output voltage fluctuates. become. Therefore, it is desirable to keep the lap period as short as possible. The load transfer circuit 117a of FIG. 9 solves this purpose.

FIG. 10 shows the internal structure of the load transfer circuit 117a. In the figure, 202 is the change amount alleviator 20.
It is a comparator that inputs an input / output signal of 0 and outputs a load transition period signal when the two signals do not match. Others are Figure 7
Is the same as. FIG. 11 is a timing chart showing the operation in this case. For example, the case of switching from the inverter shown in the upper stage to the bypass will be described.
ON from the switching signal generator 115 to the bypass switch 5a
A command is sent and the lap period starts. When the bypass switch 5a is actually closed, the closing current detection signal is received and the load current switching signal changes from "H"("1") level to "
The change amount easing device 20 falls to the L ″ (“0”) level
Based on the relaxation output signal of 0, the gradual switching control is started. At the same time, the load transition period signal from the comparator 202 rises.

As the switching control progresses, the change amount alleviator 20
When the output signal of 0 reaches the "L"("0") level, the load transition period signal from the comparator 202 falls. The switching signal generator 115 sends an OFF command to the inverter switch 5b at the falling timing of the load transition period signal to immediately end the lap period. in this way,
Since the lap period is released immediately after the completion of load transfer, the lap period can be kept to the minimum time required for switching.

When switching from the commercial power supply 7 to the inverter 2 shown in the lower part of FIG. 11, the operation is basically the same as the operation described in the upper part, and the description thereof is omitted, but the lap period is the minimum necessary. It has the same effect in that it can be kept in time.

Sixth Embodiment FIG. 12 shows a configuration of an inverter device according to a sixth embodiment of the present invention, and is a configuration diagram when two inverter circuits are operated in parallel. In the figure, reference numeral 25 is a shared current detection circuit as shared current detection means for inputting operation information of each inverter circuit and a load current detection value from the current sensor 24 and calculating a shared current per inverter circuit, 8a, Reference numeral 8b is an inverter circuit, the internal structure of which is shown in FIG.

In FIG. 13, circuit components are shown in FIG.
However, the voltage sensor 22 is connected to the output side of the inverter switch 5 in order to detect the output voltage of the inverter circuit of another unit instead of the commercial power supply voltage.
The ON / OFF command sent from the switching signal generator 115 to the inverter switch 5 is the operation information of the inverter circuit as it is (“1” when ON, “0” when OFF).
Is sent to the shared current detection circuit 25 as. In addition, the shared current from the shared current detection circuit 25 is the load transfer circuit 117.
Sent to.

Next, the operation will be described. As can be seen from the fourth embodiment, the inverter device can be operated in parallel with the commercial power source in accordance with an arbitrary load current command, and thus can be continuously operated while sharing the load with other power sources. At this time, grasp the number of operating units from the operating information output from each inverter, divide the load current by that number to obtain the current that should flow per unit, and input that value to all devices to share the load. It is possible to operate continuously while. The shared current detection circuit 25 of FIG. 12 executes the process represented by the following equation and outputs the shared current common to each device to the respective inverter circuits 8a and 8b. Current sharing = load current / (sum of operating conditions)

In each inverter circuit, the cross current control circuit 11
2 operates and performs control to modify its voltage command so that its output current equals the commanded shared current.
Therefore, switching of the operating states of the respective inverter circuits 8a and 8b is prevented, and the occurrence of cross current is always prevented in response to the change to achieve reliable operating characteristics. Further, during the transition in which these operating states are switched, the load transfer circuit 117 functions to relax the degree of temporal change in the shared current and realize smooth transfer control.
Although FIG. 12 shows the case of two inverter circuits,
It goes without saying that the present invention can also be applied to the case of arbitrary plural units.

Embodiment 7. In the sixth embodiment, the device capacities of the respective inverter circuits are the same. Therefore, the shared currents to be simultaneously sent to the respective inverter circuits may be the same values, but the device capacities of the respective inverter circuits are the same. If they are not the same,
It is necessary to determine the shared current of each machine in consideration of this difference in device capacity. The seventh embodiment is for operating in parallel inverter circuits having different device capacities (rated capacities), and the configuration thereof is shown in FIG. Here, it is assumed that three inverter circuits 8a, 8b, 8c having different capacities are operated in parallel, and the internal configuration of the shared current detection circuit 25a for outputting the shared current to be sent to each inverter circuit is shown in FIG. .

In FIG. 15, the selectors 210a, b,
The c inputs the operation information of each inverter circuit unit, and outputs signals Pr ₁ , Pr ₂ and Pr ₃ that set the shared load factor of the unit when it is in the operating state and zero when it is not in the operating state. Here, the shared load factors pr ₁ , pr ₂ , and pr ₃ indicate the ratio of the device capacity of each machine to the total of the device capacities of the inverter circuits of the first to third machines, for example, the rated capacity of the first machine is 20 KVA, Unit 2 is 50KVA, Unit 3 is 3
Assuming 0 KVA, the shared load factor of each unit is as follows.

Pr ₁ = 20 / (20 + 50 + 30) = 0.2 pr ₂ = 50 / (20 + 50 + 30) = 0.5 pr ₃ = 30 / (20 + 50 + 30) = 0.3

Next, the adder 211 is connected to each selector 210.
a, 210b, 210c outputs Pr ₁ , Pr ₂ , P
adders for calculating the sum of r ₃ , 212a, 212b, 21
2c is a divider 213a, 213b, 213c that divides the outputs Pr ₁ , Pr ₂ , Pr ₃ by the output of the adder 211, and outputs 213a, 212b, 212c are output from the dividers 212a, 212b, 212c.
It is a multiplier that multiplies the load current detected by the current sensor 24.

By adopting the above configuration, the shared current is distributed according to the ratio of the rated capacity of each inverter circuit to the total rated capacity of the operating inverter circuit, so that an excessive load is placed on the inverter circuit having a small rated capacity. It is possible to safely and reliably realize parallel operation of different-capacity power supplies without the risk of power consumption.

The number of power sources can be applied to any number (n), and the shared current I (i) of the first machine in that case can be obtained by the following equation. I (i) = pr (i) / (ΣPr (i)) · IL where pr (i) is the shared load factor of the i-th machine, ΣPr
(I) is the sum of the output _Pr 1 to PR _n of first unit to the n Unit selector shown in FIG. 15, IL is the load current detection value. As described above, it is possible to operate an arbitrary number of inverter circuits having different capacities in parallel.

In each of the above embodiments, the wrapping operation between the inverter circuit and the commercial power source or the suppression of cross current when the inverter circuits are operated in parallel has been described.
INDUSTRIAL APPLICABILITY The present invention is applicable not only to these inverter circuits and commercial power supplies, but also to a case where power is supplied to a load from a plurality of power supplies including a power supply of any type that controls its output voltage so as to follow a voltage command. The same effect can be achieved.

[0053]

As described above, the power supply device according to the first aspect controls the output voltage so as to follow the voltage command.
One power source, a second power source independent of the first power source, the above
A first switch, inserted between the first power source and the load,
Note Second opening and closing inserted between the second power source and the load
Switch and the above-mentioned first and second switches for the same period of time.
Power is supplied to the above load after a lap period in which the circuit is closed.
Supply the power between the first power source and the second power source.
A power supply switching means for switching is provided, and further, the current of the load is
Load current detecting means for detecting the output current of the first power source
Output current detection means for detecting current, or both current detection means
The subtractor that calculates the deviation from the
By correcting the voltage command so that
Suppresses the cross current that flows between the above two power sources during the up period
In a power supply device having a cross current control means, the load current
Between the detection means and the subtractor, from the load current detection means
Load current for switching between load current detection output and zero output
Switching means is provided to switch from the second power source to the first power source.
At the time of replacement, check the timing of the closing operation of the first switch.
Output the output of the load current switching means at the relevant timing.
Switching from the zero output to the load current detection output,
When switching from the second power supply to the second switch,
Detects the timing at which the
Output the load current switching means above the load current detection output.
Since it has been configured to switch to zero output, during the lap period
Suppress the occurrence of cross current between the first power source and the second power source
The switching operation between power supplies is facilitated and
Reliable switching synchronized with the actual closing timing of the closure
The replacement operation becomes possible.

The power supply device according to claim 2 has the negative polarity.
Between load current detection output and zero output of load current switching means
Equipped with load transfer means to ease the degree of change over time
Therefore, the switching operation is smoothly performed.

The power supply device according to claim 3 has the negative
In load transfer means, from load current detection output to zero output
At the timing of switching completion, open the first switch,
Timing of completion of switching from zero output to the above load current detection output
I decided to open the second switch by
Can be kept to the minimum required, and
Problems such as possible voltage fluctuations are reduced.

The power supply device according to the fourth aspect complies with the voltage command.
Multiple power supplies whose output voltage is controlled to
A switch inserted between each of the sources and the load, and
Close by opening one of the switches and opening the other.
Switch off each power source to supply power to the load
In the power supply device equipped with the switching means, the current of the load is detected.
Detecting load current, output current of each power supply
Output current detection means for, from the switching command to each switch
Input the operation information of each power source,
The shared current that should be output from each power supply based on the detected load current value
Shared current detection means for detecting
A subtracter that calculates the deviation between the detected current value and the shared current
Modify the above voltage command so that the output of the subtractor of becomes zero.
The cross current control that suppresses the cross current that flows between the above power supplies.
Since it has a control means, it suppresses the occurrence of cross current between multiple power supplies.
The parallel operation is done smoothly.

[0057] The power supply device according to claim 5 in which each
Shared current detection when the device capacities of power supplies are the same
The means is the power supply in the operating state from the operation information of each power supply.
Enter the number of operating units and set the load current detection value to the above
The shared current is calculated by dividing by
Thus, the shared current can be easily detected.

The shared current of the power supply device according to claim 6
When the detection means is in the operating state from the operating information of each power source
Is the device of the relevant power supply for the total device capacity of all power supplies
When the capacity ratio (shared load ratio) is output and the machine is not in operation
Is a selector with zero output and the output sum of each selector above
The output of each adder that outputs the output of each adder
Load divider at the output of each divider
Flow current detection value to generate the shared current to be output by each power supply.
Since it has a multiplier to generate
Detection of each shared current during parallel operation of the sources is ensured.

[0059] The power supply device according to claim 7 in which each
Output from each power supply due to change in operating state of one of the power supplies
If the shared current to be changed changes,
Equipped with load transfer means to ease the degree of change and send it to the subtractor
Operation when switching power supplies that are operated in parallel
Is done smoothly.

Further, the power supply device according to claim 8 is the voltage finger.
The power supply that controls the output voltage to follow the
An inverter that converts voltage to AC voltage, and this inverter
With a reactor and a capacitor connected to the output end of the barter
Since it is equipped with an LC filter consisting of
Reliable suppression of cross current in parallel operation of power supplies including data
Done.

The electric power in the power supply device according to claim 9 is
The output current detection means of the source detects the current at the output end of the inverter.
Inverter current sensor for detection, LC filter capacitor
Capacitor voltage sensor that detects the voltage of the
From the capacitance of the capacitor and the detected value of the capacitor voltage,
Capacitor current prediction that calculates the current flowing through the capacitor
And inverter current detection value and the above capacitor current
Equipped with a subtractor that calculates the output current of the above power supply from the predicted value
This makes it easy to detect the output current of the inverter power supply.
It will be possible with the success.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an inverter device according to a first embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the inverter device of FIG.

FIG. 3 is a diagram showing a configuration of an inverter device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of an inverter device according to a third embodiment of the present invention.

5 is a timing chart for explaining the operation of the inverter device of FIG.

FIG. 6 is a diagram showing a configuration of an inverter device according to a fourth embodiment of the present invention.

7 is a diagram showing an internal configuration of a load transfer circuit 117 of FIG.

FIG. 8 is a timing chart for explaining the operation of the inverter device of FIG.

FIG. 9 is a diagram showing a configuration of an inverter device according to a fifth embodiment of the present invention.

FIG. 10 is a diagram showing an internal configuration of a load transfer circuit 117a shown in FIG.

FIG. 11 is a timing chart for explaining the operation of the inverter device of FIG.

FIG. 12 is a diagram showing a structure of an inverter device according to a sixth embodiment of the present invention.

13 is a diagram showing an internal configuration of the inverter circuit 8a of FIG.

FIG. 14 is a diagram showing a configuration of an inverter device according to a seventh embodiment of the present invention.

15 is a diagram showing an internal configuration of a shared current detection circuit 25a of FIG.

FIG. 16 is a diagram showing a configuration of a conventional inverter device.

FIG. 17 is a timing chart for explaining the operation of the inverter device of FIG.

[Explanation of symbols]

2 inverters, 3 reactors, 4 capacitors, 5
System switching circuit, 5a bypass switch, 5b inverter switch, 6 load, 7 commercial power supply, 8a to 8c
Inverter circuit, 20, 23, 24 Current sensor, 2
1, 22 voltage sensor, 25, 25a shared current detection circuit, 101 reference sine wave generator, 102 phase detector,
104 control switch, 105 adder, 106 subtractor, 107 voltage control circuit, 111 subtractor, 112
Cross current control circuit, 113 Capacitor current predictor, 114
Subtractor, 115 switching signal generator, 116 switching device,
117, 117a Load transfer circuit, 200 Change amount easing device, 201 Multiplier, 202 Comparator, 210a-2
10c selector, 211 adder, 212a to 212
c Dividers, 213a to 213c Multipliers.

Claims (9)

(57) [Claims] 1. An output voltage of which is set so as to follow a voltage command.
A first power source for controlling, a second power source independent of the first power source.
Power supply, a first power supply inserted between the first power supply and the load
Switch, inserted between the second power source and the load
The second switch, and the first and second switches described above.
After a lap period in which the circuit is closed at the same time for a fixed period, the above load
A power source for supplying power to the first power source and the second power source
Power source switching means for switching between the above
Load current detection means for detecting a load current, the first power source
Output current detection means for detecting the output current of the source, both currents
Subtractor for obtaining deviation from detection means, and this subtractor
By correcting the above voltage command so that the output of
Cross current flowing between the two power sources during the lap period
In a power supply device equipped with a cross current control means for suppressing the load current,
Switching between load current detection output and zero output from the detection means
A load current switching means is provided to perform the switching from the second power source to the first power source.
Detects the timing when the switch of the
The output of the load current switching means from the zero output to the above
When switching to the load current detection output and switching from the first power supply to the second power supply,
Detects the timing when the switch of the
The output of the load current switching means to detect the load current.
It is characterized in that the force is switched to the above zero output.
Power supply that. 2. A load current detection output of the load current switching means,
Relax the degree of change over time with zero output
The power supply device according to claim 1, further comprising load transfer means . 3. A load current detection output in the load transfer means.
First opening / closing at the timing of completion of switching from force to zero output
Open the circuit and switch from the zero output to the load current detection output.
Open the second switch at the timing of switching completion
The power supply device according to claim 2, wherein 4. The output voltage is adjusted so as to follow the voltage command.
Multiple power supplies to control, inserted between each of the above power supplies and the load
Close the inserted switch and any of the above switches.
Supply power to the load by opening the road
Power supply device provided with power supply switching means for switching each power supply
In the load current detecting means for detecting the current of the load,
Output current detection means for detecting the output current of the power source, each of the above-mentioned switching
Input the operation information of each power source from the open / close command to the
Based on these operation information and the above load current detection value,
The shared current detecting means for detecting the shared current to be output, above
Deviation between the detected output current and the shared current for each power supply
Subtractor to obtain the above, so that the output of this subtractor becomes zero
By adjusting the voltage command, the
A power supply device comprising a cross current control means for suppressing a current . 5. When the device capacities of the respective power supplies are the same as each other,
In this case, the shared current detection means operates from the operation information of each power source described above.
Input the number of power supply in operation, and set the detected load current value.
Calculate the shared current by dividing by the number of operating power supply
The power supply device according to claim 4, wherein 6. The shared current detecting means is operating information of each power source.
When operating from, the total device capacity of all power supplies
The ratio of the device capacity of the power source to the
Selector to set to zero output when not operating
An adder that calculates the output sum of each selector, each of the above selectors
A divider that divides the output of the above by the output of the above adder, and the above
Multiplying the output of each divider by the load current detection value
Having a multiplier that creates the shared current to be output
The power supply device according to claim 4, wherein the power supply device is a power supply device. 7. A change occurs in the operating state of one of the power sources.
If the shared current that each power supply should output changes,
Reduce the degree of change over time of the shared current and send it to the subtractor
A load shifting means is provided, and the load shifting means is provided.
6. The power supply device according to any one of 6 . 8. The output voltage is adjusted so as to follow the voltage command.
The power supply to be controlled is an inverter that converts DC voltage into AC voltage.
Data and the rear connected to the output of this inverter.
Equipped with an LC filter consisting of a condenser and a condenser
8. The method according to any one of claims 1 to 7, characterized in that
The power supply device according to. 9. An output current detecting means of the power supply is an inverter.
Inverter current sensor that detects the current at the output end of the
Capacitor voltage to detect the filter capacitor voltage
Sensor, capacitance of the above capacitor and voltage detection of the above capacitor
A computer that calculates the current flowing through the capacitor from the output value.
Denser current predictor and inverter current detection value and above
Calculate the output current of the above power supply from the predicted capacitor current value
9. The power supply device according to claim 8, further comprising a subtractor for