JP2001169561A - Power supply device, controller and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a problem of no detection of a ground fault until the next system linkage operation is started when the ground fault occurs in a period of small insolation for stopping the interlocking operation, in a ground fault detection system for detecting a ground fault current flowing to a commercial power system from a solar cell to a power conditioner. SOLUTION: A control circuit 21 detects the ground fault in a solar cell array based on the voltage detected by a DC voltage detector 33 when an output switch 16 for opening/closing between an inverter 1 and the commercial power system is opened and a ground switch 34 of a ground fault detector 22 is closed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device, a control device, and a control method therefor. It relates to a control method.

[0002]

2. Description of the Related Art In recent years, research and development of clean new energy has been promoted due to increasing awareness of environmental issues, and solar power generation systems using solar cells that directly convert solar energy into electric energy have become widespread. Among them,
The market of a grid-connected solar power generation system capable of converting DC power generated by a solar cell into AC power by a power conditioner and supplying the AC power to a commercial power system is expanding.

[0003] By the way, in a solar cell, insulation may be broken for some reason, and a ground fault may occur. Generally, insulation is confirmed by measuring insulation resistance with an insulation resistance meter. In some cases, the power conditioner is provided with a means for detecting the occurrence of a ground fault in the solar cell to detect the occurrence of a ground fault.

A recent power conditioner has a size,
From the viewpoint of mass, performance, and cost, there are many so-called transformerless types that do not use a transformer. The ground fault detecting means used in the transformerless type power conditioner detects a ground fault current flowing from the solar cell to the commercial power system through the power conditioner because the ground potential is applied from the commercial power system to the solar cell. (Hereinafter referred to as “ground fault current detection method”), for example, a method described in Japanese Patent Publication No. 63-49455.

[0005]

The ground fault detecting means of the ground fault current detection system is a circuit formed when a ground fault occurs in a solar cell, "solar cell"-"power conditioner"-"commercial power system". -"Earth"-Detects the current flowing in the "solar cell". For this reason, in the ground fault detecting means of the ground fault current detection method, in a state where the grid connection operation is not performed, in other words, in a state where the solar power generation system is not electrically connected to a grounded load such as a commercial power system, Even if a ground fault occurs, a ground fault cannot be detected because the above-described circuit is not formed. For example, during periods of low sunlight such as morning and evening, the power generated by the solar cell is low, the power conditioner is in a standby state, and the grid interconnection operation stops. If a ground fault occurs during this period, the ground fault will not be detected until the next system interconnection operation is started.

[0006] Some power conditioners have a so-called autonomous operation function of supplying power to a load independent of the commercial power system when a power failure occurs in the commercial power system. The load to which power is supplied during the self-sustaining operation is not grounded and is not connected to the commercial power system. Therefore, for the same reason as described above, a ground fault current does not occur even if a ground fault occurs in the solar cell. Therefore, a ground fault generated during the independent operation is not detected. Furthermore, since the self-sustaining operation function can be used not only when a power failure occurs in the commercial power system, the self-sustaining operation may be performed for a long period of time. In this case, the ground fault remains until the next periodic inspection.

The present invention has been made to solve the above-described problem, and provides a power supply device, a control device, and a control method thereof capable of detecting a ground fault without being connected to a grounded load. The purpose is to:

Further, a power supply device capable of detecting a ground fault irrespective of connection / non-connection to a grounded load,
It is another object to provide a control device and a control method thereof.

[0009]

The present invention has the following configuration as one means for achieving the above object.

[0010] A power supply device according to the present invention is a power supply device for supplying power supplied from a DC power supply to a grounded load, wherein the power is supplied to the grounded load. Supply means, a first output switch for opening and closing between the power supply means and the ground load, and between the power input end of the device and the ground potential, impedance means, voltage or current detection means, And, a ground fault detection circuit having a ground switch, and the power supply means, the first output switch and control means for controlling the ground fault detection circuit, the control means, the control means, the first An output switch is in an open state, and a ground fault other than the ground load is detected based on a voltage or current value detected by the voltage or current detecting means when the ground switch is closed. To.

Preferably, the apparatus further comprises difference current detection means for detecting a difference between currents flowing through a plurality of power lines between the power supply means and the first output switch, and wherein the control means comprises: When the output switch is closed and the ground switch is open, the ground fault is detected using the differential current detection means.

[0012] Further, a power supply device in which a power supply is connected to an input side and a load is connected to an output side via a switch, wherein the switch is opened and the connection to the load is cut off. The input and output are non-insulated.

A power supply device having an input terminal for connecting a power supply, a cross-current conversion circuit connected to the input terminal, and an output terminal for outputting an output of the cross-current conversion circuit to outside the device. And a ground fault detecting means connected to a power path from the input terminal to the DC / AC conversion circuit, and switching means for opening / closing an electrical connection between the DC / AC conversion circuit and the output terminal. It is characterized by.

[0014] A control method of a power supply device according to the present invention is a power supply means for supplying power to a grounded load, a power supply means having non-insulated input and output, and opening and closing between the power supply means and the grounded load. An output switch, and a ground fault detection circuit having impedance means, voltage or current detection means, and a ground switch between the vicinity of a power input terminal of the apparatus and a ground potential, and supplied from a DC power supply. A power supply device for supplying power to the ground load, wherein the first output switch is opened and the ground switch is closed, and the voltage or current is detected by the voltage or current detecting means. And detecting a ground fault other than the ground load on the basis of the voltage or current value.

Preferably, the power supply device further includes a difference current detection means for detecting a difference between currents flowing through a plurality of power lines between the power supply means and the first output switch. One output switch is closed, and
When the grounding switch is in an open state, the ground fault is detected by using the difference current detecting means.

In the control device according to the present invention, a power supply is connected to an input side, a load is connected to an output side via a switch,
A control device for detecting a ground fault of a power supply device having a ground fault detecting means, wherein the switch is controlled to an open state before the ground fault detecting means detects a ground fault. .

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a photovoltaic power generator as an electric power supply according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0018]

First Embodiment FIG. 1 is a block diagram showing a configuration example of a photovoltaic power generation device according to a first embodiment, which is a photovoltaic power generation device capable of system interconnection operation with a commercial power system. FIG. 1 shows a connection relationship between a power supply and a ground fault detecting means in the first embodiment.

Reference numeral 1 denotes a power supply. Note that the power supply 1 in the present embodiment is a photovoltaic element or a solar cell module having a photovoltaic element. The power supply 1 may be a string in which a plurality of solar cell modules are electrically connected in series, or may be an array in which electric power is electrically connected in parallel.

Reference numeral 2 denotes a current collection box, a current collection mechanism for collecting the output of the power supply 1, a switch for opening and closing the collected power, a confirmation means for confirming the output of the solar cell, a maintenance and inspection mechanism, In addition, a backflow prevention mechanism using a diode or the like is provided.

Reference numeral 3 denotes a power conditioner, which converts DC power generated by the power supply 1 and supplied from the current collection box 2 into AC power and supplies the AC power to the commercial AC system 5. The power conditioner 3 has various protection functions.

Reference numeral 4 denotes an AC distribution board, and a power conditioner 3
To connect the power output from the system to the system. The AC power distribution board 4 may be omitted and the power conditioner 3 and the commercial power system 5 may be connected. In this case, it is preferable to connect both via a breaker for safety.

[Power Conditioner] FIG. 2 is a block diagram showing a configuration example of the power conditioner 3. As shown in FIG.

The input terminal 11 inputs DC power supplied from the power supply 1 via the current collection box 2, and the output terminal 12 outputs AC power converted by the power conditioner 3. The ground terminal 13 is for connecting a part of the circuit of the power conditioner 3 to the ground.

The DC power input to the input terminal 11 is passed through a noise filter 14 on the input side composed of a capacitor or the like, and passed to a DC / AC conversion circuit 15 composed of a smoothing capacitor, a reactor L, a diode, a switching element and the like. Is input to The cross-current converter 15 is a so-called transformerless inverter. The AC power output from the cross-current converter 15 is supplied to the commercial AC system 5 via an output switch 16 for opening and closing the AC output, a noise filter 17 on the output side, and an output terminal 12.

A DC voltage detector 18 for detecting an input DC voltage value, and an AC voltage detector 19 and an AC current detector 20 for detecting output AC voltage values and AC current values. Is input to an inverter control circuit 21 composed of a microprocessor or the like. The control circuit 21 performs various controls and protection of the inverter / chopper based on various detection data.

Reference numeral 22 denotes a ground fault detection circuit for detecting a ground fault in the DC circuit. The ground fault detection circuit 22 connects the resistors 31 and 32 having the same resistance value in series between the input terminals 11 and connects the connection point (voltage division point) of both resistors to one end of the DC voltage detector 33. I do. The other end of the voltage detector 33 is connected to the ground terminal 13 via a ground switch 34 that is opened and closed by the control circuit 21. The ground potential at the voltage dividing point detected by the voltage detector 33 is sent to the control circuit 21. From the detected value of the ground potential, it is possible to determine, for example, among the plurality of solar cell modules connected in series, which solar cell module has a ground fault.

Reference numeral 23 denotes a nonvolatile memory, which can be read / written by the control circuit 21. The memory 23 only needs to be able to hold the memory when the power supply to the control circuit 21 is stopped, and may be a combination of an SRAM and a backup power supply,
Various configurations such as use of a flash memory are possible.

When detecting a ground fault, the control circuit 21 opens the output switch 16 and then closes the ground switch 34.
Then, the detection voltage of the voltage detector 33, that is, the ground potential is read. At that time, if the insulation of the power supply 1 is maintained, the detection value is zero. On the other hand, if a ground fault has occurred in the power supply 1, a voltage corresponding to the location of the ground fault is detected. After the ground fault detection process, that is, the process of determining whether or not there is a ground fault, the control circuit 21 opens the ground switch 34 and then closes the output switch 16 as necessary. In the case where the alarm occurs, the output switch 16 is kept open for safety.

If the capacitance of the power supply 1 to the ground is unbalanced, the detected value may not be zero. In this case, for example, a voltage corresponding to the unbalance may be measured at the initial stage of the installation of the power supply 1 and stored in the memory 23, and thereafter, may be processed as an offset voltage.

When a ground fault occurs somewhere between the output switch 16 and the power supply 1, a ground fault detection circuit 22 similarly detects a voltage resulting from the ground fault. If a ground fault occurs at the electrical center of the power supply 1, the detected value is zero and no ground fault is detected, but it can be said that such a ground fault occurrence probability is extremely low.

Further, a current detector can be used in place of the voltage detector 33. At that time, if the insulation of the power supply 1 is maintained, the detection value is zero. On the other hand, if a ground fault has occurred in the power supply 1, a current corresponding to the ground fault location is detected. In the following description, an example will be described in which the occurrence of a ground fault is detected by detecting all voltages. However, it is needless to say that the occurrence of a ground fault may be detected by detecting a current.

FIG. 3 is a flowchart illustrating a control procedure executed by the control circuit 21.

When power is supplied to the input terminal 11 and the power conditioner 3 is started, an initialization process relating to a general operation is performed in step S1, and the cross-current conversion circuit 15 is started. In addition, the output switch 16 and the ground switch 34
Is open when the cross-current converter 15 is stopped and immediately after startup.

Next, in step S2, the ground switch 34 is closed to detect a ground fault. In step S3, a ground fault is detected. If a ground fault is detected, the process proceeds to step S9. If the greenery is maintained, the process proceeds to step S4. Specifically, if the detected voltage value is larger than a predetermined value ΔVg, it is determined that a ground fault has occurred, and if the detected voltage value is equal to or smaller than ΔVg, it is determined that insulation is maintained. This ΔVg is, for example, a value set to about several percent of the input voltage, and may be appropriately set in consideration of the accuracy of components and a circuit time constant.

In step S4, it is determined whether or not other conditions for starting the system interconnection operation are satisfied, for example, whether or not the output voltage and the frequency of the orthogonal transform circuit 15 are appropriate. Return to S3. If the conditions are satisfied, in order to start the system interconnection operation, the ground switch 34 is opened in step S5, and the output switch 16 is closed in step S6 to start the interconnection operation. In this state, the switching operation of the cross-current conversion circuit 15, that is, the power conversion operation is controlled, and power is supplied to the AC power system 5.

In step S7, it is monitored whether or not a condition for stopping the system interconnection operation has occurred. If such a condition has occurred, in other words, if the occurrence of a ground fault has been detected, the process proceeds to step S8. After the switching operation of the cross-current converter 15 is stopped and the output switch 16 is opened to release the system interconnection, the process returns to step S2 to detect a ground fault.

On the other hand, if a ground fault is detected in step S3, the ground switch 34 is opened in step S9.
In S10, the occurrence and detection of a ground fault are recorded in the memory 23, and the operation of the cross-current converter 15 and the like is stopped in Step S11, and the stopped state of the power conditioner 3 is maintained. That is, since an abnormal state called a ground fault is detected, the stopped state is maintained for safety.

As described above, according to the present embodiment, by measuring the ground potential when the earthing switch 34 is closed in a state where the power conditioner 3 is disconnected from the commercial power system, a transformerless type is provided. Power conditioner 3
Can detect a ground fault even during a period when the system is not connected to the grid.

In general, a method of detecting a ground potential can relatively easily obtain high sensitivity compared to a method of detecting a difference current between input and output. That is, a ground fault can be detected even when a slight ground fault occurs and the ground fault resistance is relatively high.

Further, since the solar cell generates electric power according to the intensity of solar radiation, a certain voltage is generated in cloudy weather and the like.
The conditions for starting the system interconnection operation may not be reached, and the system interconnection operation may not be possible throughout the day. According to the present embodiment, a ground fault can be detected even in such a case.

The configuration of the ground fault detection circuit 22 is not limited to the one shown in FIG. For example, configurations shown in FIGS. 4A to 4C are also possible. The “+” and “−” terminals shown in those figures are connected to the input terminal 11. In any of the circuits shown in the figures, if a potential other than zero is detected when the ground switch 34 or the switches 63 and / or 64 are connected, a ground fault has occurred. Further, in the circuits shown in FIGS. 4A and 4B, by switching the switch 45, and in the circuit shown in FIG. 4C, by the combination of opening and closing of the switches 63 and 64, a ground fault is caused in either direction of the DC power line. You can know if it has occurred. For example, when the potential is measured by switching the switch 45 in the circuit of FIG.
Let Es1 be the ground potential at the point of connection with Es1, and let Es2 be the ground potential of the point of connection between the registers 42 and 43. If | Es1 |> | Es2 |, then it is from the negative line and | Es1 | <| Es2 | If so, it can be seen that a ground fault occurs from the positive electrode line.

Further, at the time of system interconnection operation (system interconnection operation can be continued), the power conditioner 3 may be disconnected from the commercial power system 5 and ground fault detection may be performed under predetermined conditions. Conditions include, for example, stopping the grid interconnection operation at a predetermined cycle, or
Various conditions are conceivable, such as stopping the system interconnection operation when the power generation amount is less than or equal to a predetermined value.

Further, by recording the ground fault detection result in the memory 23, the occurrence of a ground fault can be surely known. There is also a merit that a ground fault location can be predicted from the recorded detected voltage value. For example, the ground fault resistance value may be reduced only in rainy weather, and it may be difficult to reproduce the ground fault at the time of the investigation. In such a case, if the detected voltage is recorded as in the present embodiment, it is possible to predict a ground fault location.

Further, when recording the detection result of the ground fault,
Data indicating the date and time or the operating time after the start of the power conditioner 3 may be recorded. In this case, the ground fault occurrence situation can be grasped in more detail, and it is easy to deal with the ground fault.

Since a ground fault may be detected due to dew condensation inside the power conditioner 3, it is desirable to detect the ground fault at a predetermined cycle even after the ground fault is detected and the stopped state is maintained. If the condensation inside the power conditioner 3 is the cause, the operation can be started after the condensation has been eliminated, or if such data is recorded in the memory 23,
Needless to say, it will be useful in later investigations.

Further, when a ground fault is detected, a buzzer or
The ground fault may be notified by an LED or the like, so that prompt action can be taken against the occurrence of the ground fault.

In addition, various modifications can be made without departing from the spirit of the present invention.

That is, according to the first embodiment, by setting the output switch to the open state and the ground switch to the closed state, if a ground fault occurs, the "power supply (solar cell module)" A circuit called "impedance element (resistor)"-"earth"-"power supply" is formed. Since the ground fault is detected using the ground potential generated by this circuit,
In the case where the grid connection operation is not performed in the power control device (power conditioner) whose input and output are non-insulated, in other words, even when the commercial power system which is the ground load is not connected, the power supply such as the solar cell array is not connected. Ground fault can be detected.

Further, the solar cell module as the power supply 1 according to the first embodiment and the power conditioner 3 may be installed integrally. In that case, if the power collection means for supplying the power generated by the solar cell module to the power conditioner 3 is provided in the solar cell module, the entire power generation device can be saved in space.

[0051]

Second Embodiment A photovoltaic power generator according to a second embodiment of the present invention will be described below. In the present embodiment,
The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 5 is a block diagram showing a configuration example of a photovoltaic power generator according to the second embodiment. The difference from the first embodiment is that an ungrounded load 24 to which AC power for independent output is supplied is provided. It is. The “independent output” here is an output that supplies power to a load independent of the power system.

[Power Conditioner] FIG. 6 is a block diagram showing a configuration example of the power conditioner 3 of the present embodiment. Hereinafter, points different from the first embodiment will be described.

The load 24 is connected to an independent output terminal 25 to which AC power for independent output is output. Reference numeral 26 denotes an independent output switch for opening and closing an independent output, and 27 denotes a noise filter on the independent output side. The control circuit 21 controls opening and closing of the independent output switch 26 and the output switch 16 so that at least one of the switches is closed.

FIG. 7 is a flowchart for explaining a control procedure executed by the control circuit 21. The difference from the first embodiment shown in FIG. 3 is that steps S31 to S34 are added. Hereinafter, steps S31 to S34 will be described.

In step S31, since no ground fault has occurred, it is determined whether or not other conditions for starting the self-sustaining operation (for example, the commercial power system 5 is in a power failure state) are met. If the self-sustaining operation should be started, the process proceeds to step S32, and if not, the process proceeds to step S33.

In step S32, the independent output switch 26 is closed to start an independent operation. After the switching of the cross-current conversion circuit 15 is controlled for the self-sustaining operation to start supplying power to the load 24, the process proceeds to step S33.

In step S33, it is monitored that the conditions for stopping the self-sustaining operation (for example, the commercial power system 5 is restored) are met.
If the self-sustaining operation should be stopped, the process proceeds to step S34, and if not, the process proceeds to step S4.

In step S34, the switching of the cross-current converter 15 is stopped, the independent output switch 26 is opened to disconnect the load 24, and then the process proceeds to step S4.

As described above, while the self-sustaining operation is continued, steps S3 to S4 are repeated. When a ground fault occurs in the power supply 1, the ground fault is detected in step S3.

According to the present embodiment, it is possible to detect a ground fault in the power supply 1 even during a self-sustaining operation period in which power is supplied to the ungrounded load 24 with the commercial power system disconnected. Of course, even when the load 24 has a ground fault, the ground fault can be similarly detected if a closed loop is formed.

[0062]

Third Embodiment Hereinafter, a photovoltaic power generator according to a third embodiment of the present invention will be described. In the present embodiment,
The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The third embodiment differs from the first embodiment in the configuration of the power conditioner 3. Hereinafter, the power conditioner 3 of the third embodiment will be described in detail.

FIG. 8 shows a power conditioner 3 of this embodiment.
FIG. 3 is a block diagram showing an example of the configuration of the present embodiment, and includes a difference current detector 28 that is arranged between the output switch 16 and the AC current detector 20 and detects a difference current in the AC power line. The detection value of the difference current detector 28 is sent to the control circuit 21.

FIG. 9 is a flowchart for explaining a control procedure executed by the control circuit 21. The difference from the first embodiment shown in FIG. 3 is that steps S41 and S42 are added. Hereinafter, steps S41 and S42 will be described.

In step S41, the presence or absence of a ground fault is determined based on whether a difference current is detected, specifically, whether the value of the detected difference current is greater than a predetermined value. If the value of the difference current is larger than a predetermined value, it is determined that a ground fault has occurred, and
Proceed to S42. Otherwise, it is determined that no ground fault has occurred, and the process proceeds to step S27. Therefore, when the system interconnection operation is continued, steps s41 and S7 are repeated.

In step S42, since a ground fault is detected due to the difference current during the system interconnection operation, the switching of the DC / AC conversion circuit 15 is stopped, the output switch 16 is opened, and the process proceeds to step S10. Of course, in step S10, whether the ground fault is detected by the ground voltage or the difference current is stored in the memory.
Record at 23.

As described above, according to the present embodiment, the ground fault is detected by the difference current during the grid connection operation period, and the ground fault is detected by the ground potential while the grid connection operation is stopped. Therefore, a ground fault can be detected regardless of whether or not the system interconnection operation is performed.

The ground fault detection based on the difference current and the ground fault detection based on the ground potential each have undetectable conditions (such as a ground fault location and a ground fault resistance). Conditions (areas) can be complemented with each other, and this has the effect of narrowing the conditions under which ground fault detection is not possible.

Also in the present embodiment, when the system interconnection operation can be continued, the system interconnection operation may be temporarily stopped under a predetermined condition to detect a ground fault based on the ground potential. In this case, a ground fault at a level that cannot be detected by the difference current may be detected by ground fault detection based on the ground potential, and the ground fault can be detected early. For example, the ground fault resistance value of a ground fault at which a difference current of 20 mA is detected is at most about 10 kΩ, but a ground fault having a ground fault resistance value of several hundred kΩ with maximum sensitivity is easily detected by detecting a ground potential. Detection can be performed, and detection sensitivity can be extremely increased.

Further, the ground fault may be detected by the difference current, and after the stop and hold (S23), the ground fault may be detected by the ground potential. In some cases, a ground fault location that cannot be determined only by detecting the difference current can be specified, which is useful for investigating a ground fault later.

Further, each of the above-described embodiments is not limited to the grid-connected power conditioner, and is applicable to a DC / DC converter that converts input DC power into DC power having different voltages. That is, the DC / DC converter 15 in FIGS. 2, 6 and 8 can be replaced with a DC / DC converter.

In addition, various modifications are possible within the scope of the present invention.

According to each of the embodiments described above, the voltage divider is connected between the output lines of the DC power supply, and the voltage detector is connected between the voltage dividing point of the voltage divider and the ground potential. Then, a ground fault can be detected based on the detection value of the voltage detector.
Therefore, according to each embodiment, the following effects can be obtained. (1) In a transformerless type grid-connected power conditioner, a ground fault can be detected by detecting a ground potential even when the grid-linked operation is stopped. (2) Especially in the case of a solar cell, the grid connection operation may be stopped all day depending on the solar radiation conditions, and the effect of the above (1) is large. (3) Ground fault can be detected even during self-sustaining operation. The effect is particularly great when operating independently for a long time. (4) Further, at the time of the system interconnection operation, by detecting the ground fault by the difference current, the ground error can be detected regardless of the system interconnection operation. (5) If the ground fault detection based on the difference current is added as in the above (4), the ground fault detection based on the difference current and the ground potential is performed, so that the condition (area) where the ground fault cannot be detected can be narrowed. it can. (6) The ground fault can be detected early by temporarily stopping the system interconnection operation and detecting the ground fault by the ground potential. (7) By recording the detected ground fault in the non-volatile memory, the occurrence of the ground fault can be known later. Furthermore, by recording the detected value at the time of occurrence of the ground fault in the memory, the location of the ground fault can be easily estimated.

[0075]

Further, another object of the present invention is to supply a storage medium (or a recording medium) on which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and to provide the system or the apparatus. It is needless to say that the present invention can also be achieved by a computer (or CPU or MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. The functions of the above-described embodiments are not only realized by the computer executing the readout program code, but also the operating system running on the computer based on the instructions of the program code.
It goes without saying that the (OS) or the like performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. Needless to say, the CPU included in the function expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

When the present invention is applied to the storage medium, the storage medium stores program codes corresponding to the flowcharts described above.

[0078]

As described above, according to the present invention,
It is possible to provide a power supply device capable of detecting a ground fault without being connected to a grounded load and a control method thereof.

Further, it is possible to provide a power supply device capable of detecting a ground fault regardless of connection / non-connection to a grounded load and a control method thereof.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a solar power generation device according to a first embodiment;

FIG. 2 is a block diagram showing a configuration example of a power conditioner shown in FIG. 1;

FIG. 3 is a flowchart illustrating a control procedure executed by the control circuit shown in FIG. 2,

FIG. 4A is a diagram showing another configuration example of the ground fault detection circuit;

FIG. 4B is a diagram showing another configuration example of the ground fault detection circuit;

FIG. 4C is a diagram showing another configuration example of the ground fault detection circuit;

FIG. 5 is a block diagram illustrating a configuration example of a solar power generation device according to a second embodiment;

FIG. 6 is a block diagram showing a configuration example of the power conditioner shown in FIG. 5;

FIG. 7 is a flowchart illustrating a control procedure executed by the control circuit shown in FIG. 6,

FIG. 8 is a block diagram illustrating a configuration example of a power conditioner according to a third embodiment;

FIG. 9 is a flowchart illustrating a control procedure executed by the control circuit illustrated in FIG. 8;

[Explanation of symbols]

 1 Power supply 5 Commercial AC system 11 Input terminal 12 Output terminal 13 Ground terminal 14 Input noise filter 15 Cross-current converter 16 Output switch 17 Output noise filter 25 Independent output terminal 26 Independent output switch 27 Independent output noise filter 28 Differential current detector 34 Ground switch

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Naoki Manabe 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2G014 AA04 AB61 AC17 AC18 5H007 AA17 BB07 CA01 CB05 CC12 DB01 DB12 DC02 DC05 FA02 FA12 FA14 5H420 BB03 BB12 CC03 CC10 DD03 DD10 EA12 EA49 EB13 EB39 FF03 FF04 FF22 FF25 LL03 LL09 5H730 AA12 AA17 AA20 BB14 DD04 EE07 FD11 FG01 XX02 XX13 XX22 XX33 XX44

Claims (19)

[Claims] 1. A power supply device for supplying power supplied from a DC power supply to a grounded load, comprising: a power supply unit for supplying power to the grounded load, the input / output of which is non-insulated; A first output switch for switching between means and the ground load; and an impedance means, a voltage or current detecting means, and a ground switch between a power input end of the device and a ground potential. A ground fault detection circuit, comprising: a power supply unit, a control unit that controls the first output switch and the ground fault detection circuit, wherein the control unit opens the first output switch, And a power supply device for detecting a ground fault other than the ground load based on a voltage or current value detected by the voltage or current detection means when the ground switch is closed. 2. The apparatus according to claim 1, further comprising: a difference current detection unit configured to detect a difference between currents flowing through a plurality of power lines between the power supply unit and the first output switch. 2. The power supply device according to claim 1, wherein the ground fault is detected using the differential current detection means when an output switch is closed and the ground switch is open. And a second output switch for switching between the power supply means and the non-grounded load to supply power to the non-grounded load, wherein the control means comprises: When one of the first and second output switches is open, the other is controlled to be closed,
3. The power supply device according to claim 1, wherein, when the second output switch is closed, the ground switch is closed to detect the ground fault. 4. The power supply device according to claim 1, wherein the control unit controls an operation of the power supply unit based on a detection result of the ground fault. 5. The power supply device according to claim 1, wherein the control unit includes a nonvolatile memory that stores a result of the ground fault detection. 6. The power supply device according to claim 1, wherein the DC power supply is a solar cell. 7. The power supply according to claim 1, wherein the power supply unit converts the output power of the DC power supply into a form corresponding to a load and supplies the converted power. apparatus. 8. The power supply device according to claim 1, wherein the ground load is a power system. 9. A power supply means for supplying power to a grounded load, the input / output of which is non-insulated, a first output switch for opening and closing between the power supply means and the ground load, and the device. And a ground fault detection circuit having impedance means, voltage or current detection means, and a grounding switch between the vicinity of the power input terminal of the power supply terminal and the ground potential, and supplies power supplied from a DC power supply to the ground load. A method of controlling a power supply device, comprising: opening the first output switch, and closing the ground switch, based on a voltage or current value detected by the voltage or current detection unit, A control method characterized by detecting a ground fault other than a ground load. 10. The power supply device further includes a difference current detection means for detecting a difference between currents flowing through a plurality of power lines between the power supply means and the first output switch, 10. The control method according to claim 9, wherein when the output switch is closed and the ground switch is open, the ground fault is detected using the difference current detection means. 11. The power supply device further includes a second output switch that opens and closes between the power supply unit and the non-grounded load to supply power to a non-grounded load, When one of the first and second output switches is open, the other is controlled to be closed, and when the second output switch is closed, the ground switch is closed and the ground fault is performed. 11. The control method according to claim 9 or claim 10, wherein the control method detects: 12. The control method according to claim 9, wherein an operation of the power supply unit is controlled based on a detection result of the ground fault. 13. The control method according to claim 9, wherein when the ground fault is detected, a detection result is recorded in a memory of the device. 14. An insulated power supply means for supplying power to a grounded load, a first output switch for opening and closing between the power supply means and the ground load, and
An impedance means, a voltage or current detection means, and a ground fault detection circuit having a ground switch provided between the vicinity of a power input end of the device and a ground potential, and power supplied from a DC power supply is supplied to the ground load. A recording medium on which a program code for controlling a power supply device to be supplied is recorded, wherein the program code includes at least: an open state of the first output switch; and a closed state of the ground switch. A recording medium comprising: a code; and a code for detecting a ground fault other than the ground load based on a voltage or current value detected by the voltage or current detecting means. 15. A power supply device in which a power supply is connected to an input side and a load is connected to an output side via a switch, wherein the switch is opened and the connection to the load is cut off. A power supply device, comprising: a ground fault detecting unit that performs non-insulated input / output and detects a ground fault in the power supply. 16. The power supply device according to claim 15, further comprising control means for opening the switch at least prior to ground fault detection. 17. A control device for detecting a ground fault of a power supply device having a power supply connected to an input side, a load connected to an output side via a switch, and having a ground fault detecting means, A control device, wherein the switch is controlled to an open state before a ground fault detecting means detects a ground fault. 18. A power supply device having an input terminal for connecting a power supply, a cross-current converter connected to the input terminal, and an output terminal for outputting an output of the cross-current converter to outside the device. And a ground fault detecting means connected to a power path from the input terminal to the DC / AC conversion circuit, and switching means for opening / closing an electrical connection between the DC / AC conversion circuit and the output terminal. A power supply device characterized by the above-mentioned. 19. The power supply device according to claim 18, further comprising control means for opening the switch at least prior to ground fault detection.