JP2018207594A - Power supply device and welding determination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily detect welding of an auxiliary input opening / closing part without depending on the performance of a single opening / closing part in a power supply device including grid interconnection, independent output and auxiliary input. SOLUTION: An AC electric circuit on the AC side of an inverter is connected to a commercial power system at a first voltage via a grid interconnection switching unit, branches from the AC electric circuit, and is connected to a commercial power system via a self-sustaining output switching unit. A first voltage sensor that has a circuit that outputs at a second voltage lower than the voltage of the AC circuit and guides the auxiliary input to the AC electric circuit via the auxiliary input switching part, and detects the voltage between the two lines of the AC electric circuit. An inverter with a second voltage sensor that detects the voltage between the two wires connecting the auxiliary input switch and the auxiliary input terminal, and a control that opens all three switches and has no auxiliary input. A control unit that outputs an inspection voltage that is lower than the second voltage and is not used regularly, and determines that the auxiliary input switching unit is welded when the second voltage sensor detects a voltage based on the inspection voltage. And have. [Selection diagram] Fig. 1

Description

  The present invention relates to a power supply device and a welding determination method.

  A power conditioner (power conversion device) that performs grid connection with a commercial power system is provided with a function of opening and closing a switching unit (relay contact) and disconnecting from the grid when grid connection is not performed. In addition to grid connection, power conditioners capable of independent output are provided with an open / close section between the output terminals and open the open / close section to prevent voltage from appearing at the independent output terminal during grid connection operation. (For example, refer to FIG. 1 of Patent Document 1).

  Since the relay used as such an opening / closing part cannot perform the disconnection function if it is welded, a relay having an auxiliary contact for detecting welding of the relay contact is used. Such relays are relatively expensive. Another feature is that the return time from the closed state to the open circuit is relatively long.

JP 2017-11929 A

  In recent years, there is a self-sufficiency system of electric power that does not sell the power generated by solar power generation but stores it in a storage battery and uses it by consumers. For example, some power supply devices such as UPS (Uninterruptible Power Supply) equipped with a storage battery can charge the storage battery and discharge to the consumer while being connected to the commercial power system. As an auxiliary input other than the commercial power system, for example, if AC 100 V is provided from a photovoltaic power conditioner, power can be stored and used without waste.

  In this case, the power supply device includes three systems of input / output: grid connection, independent output, and auxiliary input. A relay for disconnection is also required for the auxiliary input circuit, but the above-mentioned relay with a long recovery time cannot be used because of the UPS standard. However, if a relay with a short recovery time is employed, welding cannot be detected because there is no auxiliary contact for welding detection.

  In view of such a problem, the present invention is an easy-to-use power source apparatus having three systems of input / output of grid connection, self-sustained output, and auxiliary input, and does not depend on the performance of the open / close unit alone. The purpose is to enable detection.

  A power supply device according to an expression of the present invention is a power supply device that includes an inverter and performs conversion from direct current to alternating current or vice versa, and the first voltage is supplied via an alternating current circuit on the alternating current side of the inverter. A system connection terminal connected to a commercial power system, a system interconnection switching unit provided between the AC power circuit and the system connection terminal, a first branching from the AC circuit and lower than the first voltage A self-supporting output terminal that outputs at a voltage of 2, a self-supporting output opening / closing unit provided between the AC circuit and the self-supporting output terminal, an auxiliary input terminal that accepts an auxiliary input from the outside, the AC circuit, and the auxiliary Auxiliary input opening / closing portion provided between the input terminal, a first voltage sensor for detecting a voltage between two lines of the AC circuit, and two wires connecting the auxiliary input opening / closing portion and the auxiliary input terminal. A second voltage sensor for detecting the voltage between And a function for performing switching control of the inverter, and a control for opening all of the grid interconnection switching unit, the independent output switching unit, and the auxiliary input switching unit, and the auxiliary When there is no input, the inverter outputs a test voltage that is lower than the second voltage and is not normally used, and the second voltage sensor does not detect a voltage based on the test voltage. And a control unit having a function of determining that the auxiliary input switching unit is welded when a voltage based on the inspection voltage is detected.

  In addition, the welding determination method according to an expression of the present invention includes an inverter, a function of interconnecting with the commercial power system and the grid connection via the first voltage, and a self-sustained output switching section. In a power supply apparatus having a function of providing a self-sustained output at a voltage 2 lower than the first voltage and a function of receiving an auxiliary input from the outside via an auxiliary input opening / closing section, a control section of the power supply apparatus performs It is a welding determination method, which controls to open all the open / close part for grid connection, the open / close part for independent output, and the open / close part for auxiliary input, and has no auxiliary input, In this state, the inverter is caused to output a test voltage that is lower than the second voltage and is not normally used, and a voltage based on the test voltage is not detected between the auxiliary input switching unit and the auxiliary input terminal. If the above Auxiliary input switching unit normal, when the voltage based on the inspection voltage is detected, it is determined that the auxiliary input opening portion is welded.

  According to the present invention, it is possible to easily detect the welding of the auxiliary input opening / closing portion without depending on the performance of the opening / closing portion alone.

It is a figure which shows the circuit structure of a power supply device. It is a figure which shows an example of the circuit structure inside a power converter. It is the figure similar to FIG. 1, and is the figure which showed concretely the operation | movement of each opening-and-closing part at the time of grid connection. FIG. 2 is a diagram similar to FIG. 1, specifically showing the operation of each opening / closing unit during independent output. FIG. 2 is a diagram similar to FIG. 1, specifically showing the operation of each open / close section during auxiliary input. FIG. 2 is a diagram specifically showing the operation of each opening / closing section when the auxiliary input opening / closing section is welded and there is no auxiliary input in the same diagram as FIG. 1. FIG. 2 is a diagram specifically showing the operation of each opening / closing section when the auxiliary input opening / closing section is welded and there is an auxiliary input in the same diagram as FIG. 1. It is a flowchart which shows an example of the welding check of the opening / closing part for auxiliary inputs. It is a flowchart which shows the other example of the welding check of the opening / closing part for auxiliary inputs. FIG. 2 is a view similar to FIG. 1, showing a state in which the independent output opening / closing section is welded and the grid connection opening / closing section and the auxiliary input opening / closing section are normally opened.

[Summary of Embodiment]
The gist of the embodiment of the present invention includes at least the following.

  (1) This is a power supply device that is equipped with an inverter and performs conversion from DC to AC or vice versa, and is connected to the commercial power system at a first voltage via an AC circuit on the AC side of the inverter. A system connection terminal, a system interconnection switching unit provided between the AC circuit and the system connection terminal, and a second voltage that is branched from the AC circuit and is lower than the first voltage. A self-supporting output terminal, a self-supporting output opening / closing portion provided between the AC circuit and the self-supporting output terminal, an auxiliary input terminal receiving an auxiliary input from the outside, and between the AC circuit and the auxiliary input terminal Auxiliary input opening / closing section provided on the first circuit, a first voltage sensor for detecting a voltage between the two lines of the AC circuit, and a voltage between the two lines connecting the auxiliary input opening / closing section and the auxiliary input terminal are detected. A second voltage sensor, and the invar A function of performing the switching control of the system, and a state in which the system interconnection switching unit, the independent output switching unit, and the auxiliary input switching unit are all opened, and there is no auxiliary input When the inverter outputs a test voltage that is lower than the second voltage and is not normally used, and the second voltage sensor does not detect a voltage based on the test voltage, the auxiliary input switching unit is normal. And a control unit having a function of determining that the auxiliary input opening and closing unit is welded when a voltage based on the inspection voltage is detected.

  In such a power supply device, the grid connection open / close unit, the independent output open / close unit, and the auxiliary input open / close unit should all be opened, and the inverter is lower than the second voltage and is not commonly used. By outputting the inspection voltage, it is possible to determine whether or not the auxiliary input opening / closing portion is welded. That is, if the auxiliary input opening / closing part is normally opened, the second voltage sensor does not detect a voltage based on the inspection voltage. On the other hand, when the second voltage sensor detects a voltage based on the inspection voltage, it can be determined that the auxiliary input opening / closing portion is welded. In this way, even when the auxiliary input opening / closing section itself does not have a function of sending a welding signal to the outside, it is possible to determine whether the auxiliary input opening / closing section is welded or not by verification using the inspection voltage. Since the inspection voltage is lower than the second voltage, it is possible to prevent damage to circuit elements and suppress electric shock to the human body.

(2) Further, in the power supply device of (1), a noise filter is provided between the self-supporting output terminal and the self-supporting output opening / closing part, and a current flows between the noise filter and the self-supporting output opening / closing part. There may be provided a current sensor for detecting.
In this case, it is possible to detect the welding of the opening / closing part for the self-supporting output. In other words, when the inverter outputs the test voltage or the second voltage with the control for opening the self-sustained output open / close section, if the current sensor does not detect the current, the self-sustained output open / close section is normal. Yes, when the current sensor detects a current due to the current flowing through the capacitance component of the noise filter or the specific load connected to the self-supporting output terminal, it can be determined that the open / close unit for self-supporting output is welded.

  (3) Further, from the viewpoint of the method, an inverter is mounted, and the first power supply is connected to the commercial power system via the first connection voltage via the first voltage via the first voltage switching function. In a power supply apparatus having a function of providing a self-sustained output at a voltage of 2 lower than the voltage of 2 and a function of accepting an auxiliary input from the outside via an auxiliary input opening / closing section, a welding determination method performed by the control section of the power supply apparatus And (a) controlling to open all of the grid connection switching unit, the independent output switching unit, and the auxiliary input switching unit, and without the auxiliary input, b) In this state, the inverter is caused to output a test voltage that is lower than the second voltage and is not used regularly, and (c) the test voltage between the auxiliary input opening / closing unit and the auxiliary input terminal. If no voltage based on is detected, Serial auxiliary input for opening and closing unit is normal, when the voltage based on the inspection voltage is detected, the determined auxiliary input opening portion is welded, a welding determination method.

  In the welding determination method in such a power supply device, the grid connection open / close unit, the independent output open / close unit, and the auxiliary input open / close unit should all be opened, and the inverter is connected to the second voltage. By outputting a low inspection voltage that is not normally used, it is possible to determine whether or not the auxiliary input opening / closing portion is welded. That is, if the auxiliary input opening / closing part is normally opened, the second voltage sensor does not detect a voltage based on the inspection voltage. On the other hand, when the second voltage sensor detects a voltage based on the inspection voltage, it can be determined that the auxiliary input opening / closing portion is welded. In this way, even when the auxiliary input opening / closing section itself does not have a function of sending a welding signal to the outside, it is possible to determine whether the auxiliary input opening / closing section is welded or not by verification using the inspection voltage. Since the inspection voltage is lower than the second voltage, it is possible to prevent damage to circuit elements and suppress electric shock to the human body.

[Details of the embodiment]
Hereinafter, a power supply device and a welding detection method according to an embodiment of the present invention will be described with reference to the drawings.

<< Circuit configuration example >>
FIG. 1 is a diagram illustrating a circuit configuration of the power supply device 100. The power supply apparatus 100 is provided between the storage battery 1 at the terminal on the DC side and three external AC circuits of “system interconnection”, “self-sustained output”, and “auxiliary input”. In the figure, the description will be made assuming that the more upstream the battery is, the closer to the alternating current side as viewed from the storage battery 1.

  Note that the storage battery 1 is a constituent element of the power supply apparatus 100 if it is built in the power supply apparatus 100. However, for example, if the storage battery 1 is externally installed (separately installed), it is not necessarily a constituent element of the power supply apparatus 100. There are some things I can't say.

  First, with respect to the main circuit element, the power converter 2 is connected to the DC output (P line, N line) of the storage battery 1. The power conversion unit 2 can perform bidirectional conversion from direct current to alternating current or vice versa. An LC filter circuit including an AC reactor 3 and an AC capacitor 4 and a noise filter (internal configuration is a common mode choke, the same applies hereinafter) 5 are connected to the AC side of the power conversion unit 2. On the upstream side of the noise filter 5, there is an internal AC circuit (AC bus) 6 that is common to three external AC circuits of “system interconnection”, “self-sustained output”, and “auxiliary input”.

  Between the AC circuit 6 and the system connection terminal 12 of the system connection, a system connection switching unit (system connection relay) 7, a capacitor 8, a varistor 9, and a series body of varistors 10 and 11 Is provided as shown.

  The grid connection opening / closing section 7 has contacts that can be opened and closed on the U-line side and the W-line side, respectively. For example, an AC voltage of 200 V is applied between the U line and the W line. An intermediate connection point of the series body of the varistors 10 and 11 is connected to the O (N) line of the system connection terminal 12. Therefore, an AC voltage of 200 V is applied between the U line and the W line of the system connection terminal 12, and an AC voltage of 100 V is applied between the U line and the O line and between the W line and the O line.

Next, between the AC circuit 6 and the self-supporting output terminal 18, a capacitor 13, a self-supporting output opening / closing part (self-supporting output relay) 14, a fuse 15, a varistor 16, and a noise filter 17 are illustrated. It is provided as follows.
The independent output opening / closing part 14 has contacts that can be opened and closed on the L1 line side and the N1 line side, respectively. For example, AC 100V is output between the L1 line and the N1 line.

  Further, between the AC circuit 6 and the auxiliary input terminal 24, auxiliary input opening / closing sections 19p and 19n, a noise filter 20, a capacitor 21, a fuse 22, and a varistor 23 are provided as shown in the figure. ing. The two contacts of the auxiliary input opening / closing portions 19p and 19n are opened and closed in synchronization. Hereinafter, 19p and 19n are collectively referred to as an auxiliary input opening / closing section 19. In addition, although it is an example advantageous in terms of cost to use two 1-contact relays, it is divided into 2 contacts, but is not limited to this, and may be one opening / closing part having 2 contacts. .

  The auxiliary input opening / closing part 19p has an openable / closable contact on the L line side. The auxiliary input opening / closing part 19n has a contact that can be opened and closed on the N-line side. For example, 100 V AC is input from the outside between the L line and the N line.

  Circuit components for measurement control include a current sensor 31 that detects the current flowing through the AC reactor 3, a voltage sensor 32 that detects the voltage across the capacitor 8, a voltage sensor 33 that detects the voltage across the varistor 11, and a capacitor. 13, a voltage sensor 34 that detects the voltage across both ends, a current sensor 35 that is provided on the N1 line side between the self-contained output switching unit 14 and the noise filter 17, and a voltage sensor 36 that detects the voltage across the capacitor 21. It has.

  Then, the detection output of each sensor is sent to the control unit 40. Based on this, the control unit 40 controls the opening / closing of the grid connection opening / closing unit 7, the independent output opening / closing unit 14, and the auxiliary input opening / closing unit 19.

  The control unit 40 is connected to the remote control device 50 so as to be communicable by, for example, the RS485 method. The remote control device 50 has functions for performing various settings in addition to display functions such as an operation state display, various power displays, and error code displays as the power supply apparatus 100.

  FIG. 2 is a diagram illustrating an example of an internal circuit configuration of the power conversion unit 2. In the figure, the power conversion unit 2 includes a DC capacitor 201, a DC / DC converter 2A, an intermediate capacitor 204, and an inverter 2B in order from the DC side. The DC / DC converter 2A includes a first chopper circuit configured by a DC reactor 202, a high-side switching element Q1, and a low-side switching element Q2, a DC reactor 203, a high-side switching element Q3, and a low-side The second chopper circuit configured by the switching element Q4 is connected in parallel.

Inverter 2B includes switching elements Q5, Q6, Q7, and Q8 that form a full bridge circuit.
The switching elements Q1 to Q8 are, for example, IGBTs (Insulated Gate Bipolar Transistors), but may be MOS-FETs (Metal-Oxide-Semiconductor Field Effect Transistors).

  As a circuit element for measurement control, a voltage sensor 205 is connected to both ends of the DC side capacitor 201, and this voltage sensor 205 detects an input voltage and sends a detection output to the control unit 40. Current sensors 206 and 207 detect currents flowing through DC reactors 202 and 203, respectively, and send detection outputs to control unit 40. The voltage sensor 208 connected to both ends of the intermediate capacitor 204 detects the DC link voltage and sends the detection output to the control unit 40. Switching elements Q1-Q8 are controlled by control unit 40.

  The control unit 40 includes, for example, a computer, and realizes necessary control functions by causing the computer to execute software (computer program). The software is stored in a storage device (not shown) of the control unit 40. The power supply voltage (Vcc) of the control unit 40 can be obtained from the storage battery 1, for example.

  When the storage battery 1 is discharged, the voltage is boosted by the DC / DC converter 2A, and the boosted DC voltage is converted into an AC voltage by the inverter 2B. When charging the storage battery 1, the inverter 2B performs full-wave rectification of the alternating current, and further the DC voltage smoothed by the intermediate capacitor 204 is stepped down to a voltage suitable for charging by the DC / DC converter 2A.

<Operation during grid connection>
FIG. 3 is a diagram similar to FIG. 1 and specifically showing the operation of each open / close section (7, 14, 19p, 19n) during grid connection. In the figure, at the time of grid connection, the control unit 40 closes the grid connection switching unit 7 and opens the other independent output switching unit 14 and auxiliary input switching unit 19. In this state, for example, when the storage battery 1 is discharged, the power conversion unit 2 outputs AC 200V. Therefore, the system connection terminal 12 is provided with a single-phase three-wire output. When charging the storage battery 1, the direction of energy is reversed.

  AC 200V is applied to the AC circuit 6 at the time of grid connection, but the open / close unit for independent output 14 and the open / close unit for auxiliary input 19 are all open, so the secondary side (upstream side) of each open / close unit. AC 200V will not be applied. The capacitor 13 is selected to withstand 200V.

<Operation during autonomous operation>
FIG. 4 is a diagram similar to FIG. 1, specifically showing the operation of each open / close section (7, 14, 19 p, 19 n) at the time of independent output. In the figure, at the time of self-sustained output, the control unit 40 closes the self-sustained output open / close unit 14 and opens the other grid connection open / close unit 7 and the auxiliary input open / close unit 19. In this state, the power converter 2 discharges the storage battery 1 and outputs AC 100V. Therefore, the independent output terminal 18 is provided with a single-phase AC 100V.

<Operation when receiving auxiliary input>
FIG. 5 is a diagram similar to FIG. 1 and specifically shows the operation of each open / close section (7, 14, 19p, 19n) during auxiliary input. In the figure, at the time of auxiliary input, there are two types of operations: (a) an operation that provides a self-sustained output with an auxiliary input, and (b) an operation that charges the storage battery 1 with an auxiliary input.

In the case of (a), the control unit 40 closes the auxiliary input opening / closing unit 19 and the independent output opening / closing unit 14 and opens the grid connection opening / closing unit 7. The power conversion unit 2 is stopped. In this state, the auxiliary input AC of 100 V can be provided as a self-supporting output.
In the case of (b), the state is not illustrated, but the control unit 40 closes the auxiliary input opening / closing unit 19 and opens the other grid connection opening / closing unit 7 and the independent output opening / closing unit 14. . Then, the control unit 40 causes the power conversion unit 2 to perform the conversion operation in the reverse direction, and stores the power of the auxiliary input in the storage battery 1.

<Checking welding before starting power supply operation>
When starting operation from a state where the power supply apparatus 100 is stopped, the control unit 40 first checks whether or not welding has occurred in each opening / closing unit. Since the grid connection switching unit 7 and the independent output switching unit 14 have a function of outputting a signal at the time of welding, the control unit 40 can perform a welding check depending on the presence or absence of the signal. If it is detected that welding has occurred based on these signals, the control unit 40 displays an error code on the remote control device 50 and does not operate the power supply device 100. If it is in a normal state without welding, it is confirmed whether or not the remaining one opening / closing part, that is, the auxiliary input opening / closing part 19 has been welded. However, since the auxiliary input opening / closing part 19 does not have a function of notifying itself of welding, an independent check is necessary. Hereinafter, this check will be described in detail.

FIG. 6 is a diagram similar to FIG. 1 and specifically shows the operation of each opening / closing part (7, 14, 19p, 19n) when the auxiliary input opening / closing part 19 is welded and there is no auxiliary input. It is a figure.
FIG. 7 is a diagram similar to FIG. 1 and specifically shows the operation of each open / close section (7, 14, 19p, 19n) when the auxiliary input open / close section 19 is welded and there is an auxiliary input. It is a figure.

<Auxiliary input opening / closing check for welding>
FIG. 8 is a flowchart showing an example of a welding check of the auxiliary input opening / closing unit 19. In the figure, when the operation start operation of the power supply apparatus 100 is performed, the control unit 40 executes the processing of this flowchart before the operation starts.

  In FIG. 8, the control unit 40 first acquires voltage information of each unit based on the detection outputs of the voltage sensors 32, 33, 34, and 36 (step S1). Next, the control unit 40 determines whether or not auxiliary input is given from the outside based on the detection output of the voltage sensor 36 (step S2). When there is no auxiliary input, the control unit 40 drives the power conversion unit 2 to output a test voltage to the AC circuit 6 (step S3). Here, the test voltage is a voltage that is lower than the voltage (second voltage: AC100V) at the time of self-sustained output lower than the voltage at the time of grid connection (first voltage: AC200V). Specifically, for example, it is a safe voltage of about AC 40V, in which even if a person touches directly with the skin, a current that causes danger to the human body does not flow.

  Here, the voltage (V1) of the AC circuit 6 by the output of the power converter 2 can be detected by the voltage sensor 34, and V1≈40V. On the other hand, if the auxiliary input opening / closing part 19 is normally opened, the voltage (V2) detected by the voltage sensor 36 is V2 = 0V. Therefore, V1 and V2 are clearly different from each other, and it can be seen that the auxiliary input opening / closing part 19 is normal (no welding) (No in step S4). In this case, the control unit 40 can start operation (step S8).

  On the other hand, when V2≈V1, that is, when the voltage sensor 36 detects a voltage based on the inspection voltage, it is determined that welding has occurred (Yes in step S4), and the control unit 40 opens and closes the auxiliary input opening / closing unit. An error code indicating 19 welding is displayed on the remote control device 50 (step S5). And the control part 40 stops the driving | operation of the power supply device 100 (step S6). Note that the inspection voltage is significantly different from the normally used voltage (AC200V or AC100V), so it can be said that there is virtually no possibility of AC40V being detected by accident for some reason, resulting in erroneous detection of welding.

  On the other hand, when there is an auxiliary input in step S2, the control unit 40 determines whether or not the welding condition is satisfied with the auxiliary input (step S7). Assuming that the auxiliary input opening / closing part 19 is welded, the voltage V2 detected by the voltage sensor 36 when the auxiliary input is present is near 100V, and the voltage V1 detected by the voltage sensor 34 is substantially the same. In a normal state where welding is not performed, when there is an auxiliary input, the voltage V2 detected by the voltage sensor 36 is near 100V, whereas the voltage V1 detected by the voltage sensor 34 is approximately 0V. Therefore, the welding condition is V2≈V1, and the normal condition is V2 ≠ V1.

  If the condition is not satisfied in step S7, the operation is started (step S8). Conversely, if the condition is satisfied, the control unit 40 causes the remote controller 50 to display an error code indicating welding of the auxiliary input opening / closing unit 19 (step S5). . And the control part 40 stops the driving | operation of the power supply device 100 (step S6).

Next, FIG. 9 is a flowchart showing another example of the welding check of the auxiliary input opening / closing part 19. What is performed in this flowchart is a welding check before entering the next operation when the auxiliary input is lost.
First, when the voltage sensor 36 no longer detects an auxiliary input while receiving the auxiliary input, the control unit 40 starts the process of this flowchart. And the control part 40 performs control which opens the opening / closing part 19 for auxiliary inputs (step S0). If it is normal, the auxiliary input opening / closing unit 19 is opened. However, if it is welded, the auxiliary input opening / closing unit 19 is actually closed even though it should be opened in terms of control.

  Therefore, the control unit 40 drives the power conversion unit 2 to output a test voltage to the AC circuit 6 (step S3). Here, the test voltage is a voltage that is lower than the voltage (second voltage: AC100V) at the time of self-sustained output lower than the voltage at the time of grid connection (first voltage: AC200V). Specifically, for example, it is a safety voltage of about 40 V, which does not flow a current that may cause danger to the human body even if a person touches the skin directly.

  Here, the voltage (V1) of the AC circuit 6 by the output of the power converter 2 can be detected by the voltage sensor 34, and V1≈40V. On the other hand, if the auxiliary input opening / closing part 19 is normally opened, the voltage (V2) detected by the voltage sensor 36 is V2 = 0V. Therefore, V1 and V2 are clearly different from each other, and it can be seen that the auxiliary input opening / closing part 19 is normal (no welding) (No in step S4). In this case, the control unit 40 can start operation (step S8).

  On the other hand, when V2≈V1, that is, when the voltage sensor 36 detects a voltage based on the inspection voltage, it is determined that welding has occurred (Yes in step S4), and the control unit 40 opens and closes the auxiliary input opening / closing unit. An error code indicating 19 welding is displayed on the remote control device 50 (step S5). And the control part 40 stops the driving | operation of the power supply device 100 (step S6). Since the inspection voltage is significantly different from the normal voltage (AC 200 V or AC 100 V), it can be said that there is virtually no possibility that AC 40 V is detected by accident for some reason, resulting in erroneous detection of welding.

<Summary>
In the power supply device 100, the inverter 2B of the power conversion unit 2 is connected to the inverter 2B of the power conversion unit 2 in a state where the grid connection switching unit 7, the independent output switching unit 14, and the auxiliary input switching unit 19 are all open. Whether or not the auxiliary input opening / closing unit 19 is welded can be determined by outputting a test voltage that is not normally used and is lower than the voltage of the self-supporting output (second voltage). That is, if the auxiliary input opening / closing unit 19 is normally opened, the voltage sensor 36 does not detect a voltage based on the inspection voltage.

  On the other hand, when the voltage sensor 36 detects a voltage based on the inspection voltage, it can be determined that the auxiliary input opening / closing portion 19 is welded. Thus, even if the auxiliary input opening / closing part 19 itself does not have a function of sending a welding signal to the outside, it is possible to determine whether the auxiliary input opening / closing part 19 is welded or not by verification using the inspection voltage. Moreover, since the voltage for a test | inspection is lower than a self-supporting output voltage, damage to the 100V circuit element can be prevented, and the electric shock to a human body can be suppressed. Note that 40V is an example, and a voltage slightly higher than this, or conversely, a lower voltage may be used. However, if it is too low (for example, 10 V or less), it becomes difficult to detect, and it is difficult for the inverter 2B to output a stable voltage.

<When welding the open / close part for self-supporting output>
Although the above description has described only the welding of the auxiliary input opening / closing part 19, the same welding check can be performed for the self-sustained output opening / closing part 14. In this case, the self-supporting output opening / closing part 14 has an advantage that an inexpensive opening / closing part (relay) having no welding detection function can be employed.

  FIG. 10 is a view similar to FIG. 1, showing a state where the self-sustained output opening / closing part 14 is welded and the grid connection opening / closing part 7 and the auxiliary input opening / closing part 19 are normally opened. is there. In terms of control, the opening / closing part 14 for the self-supporting output is also controlled to open, but because of welding, it is not in accordance with the control. In this case, since no voltage sensor is provided on the self-supporting load side as viewed from the self-supporting output opening / closing part 14, welding cannot be detected by voltage comparison. Since the grid connection switching unit 7 and the auxiliary input switching unit 19 are both open, no voltage is applied from the outside.

  Therefore, consider using the current sensor 35. Since the noise filter 17 has a built-in capacitor component, a current flows when an AC voltage is applied. In addition, a specific load may be connected to the self-supporting output terminal 18. Therefore, when the test voltage AC40V or normal AC100V is output from the power conversion unit 2 and a current flows through the current sensor 35, the self-supporting output switching unit 14 is welded. If it does not flow in the reverse direction, the opening / closing part 14 for independent output is not welded and is normally opened.

  In this manner, the welding of the independent output opening / closing part 14 can be detected in the same manner. In other words, when the test voltage or the self-sustained output voltage is output to the inverter 2B of the power conversion unit 2 with the control for opening the self-sustained output opening / closing unit 14 being performed, the current sensor 35 is self-supporting if no current is detected. When the output opening / closing unit 14 is normal and the current sensor 35 detects the current due to the current flowing through the capacitance component of the noise filter 17 or the specific load connected to the independent output terminal 18, the independent output opening / closing unit 14. Can be determined to be welded.

《Supplementary Note》
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Storage battery 2 Power conversion part 2A DC / DC converter 2B Inverter 3 AC reactor 4 AC side capacitor 5 Noise filter 6 AC electric circuit 7 Grid connection opening / closing part 8 Capacitor 9, 10, 11 Varistor 12 System connection terminal 13 Capacitor 14 Independent output Opening / closing part 15 Fuse 16 Varistor 17 Noise filter 18 Self-standing output terminal 19 (19p, 19n) Auxiliary input opening / closing part 20 Noise filter 21 Capacitor 22 Fuse 23 Varistor 24 Auxiliary input terminal 31 Current sensor 32, 33, 34 Voltage sensor 35 Current Sensor 36 Voltage sensor 40 Control unit 50 Remote control device 100 Power supply device 201 DC side capacitor 202, 203 DC reactor 204 Intermediate capacitor 205 Voltage sensor 206, 207 Current sensor 208 Voltage sensor Sensor Q1-Q4 Switching element Q5-Q8 Switching element

Claims (3)

A power supply device that carries an inverter and performs conversion from DC to AC or vice versa,
A system connection terminal connected to the commercial power system at a first voltage via an AC circuit on the AC side of the inverter;
An open / close part for grid connection provided between the AC circuit and the grid connection terminal;
A self-supporting output terminal that branches off from the AC circuit and outputs a second voltage lower than the first voltage;
A self-supporting output opening / closing part provided between the AC circuit and the self-supporting output terminal;
An auxiliary input terminal that accepts an auxiliary input from the outside,
An auxiliary input opening / closing portion provided between the AC circuit and the auxiliary input terminal;
A first voltage sensor for detecting a voltage between two wires of the AC circuit;
A second voltage sensor for detecting a voltage between two lines connecting the auxiliary input opening and closing unit and the auxiliary input terminal;
A function for performing switching control of the inverter, and control for opening all of the grid interconnection switching unit, the independent output switching unit, and the auxiliary input switching unit, and the auxiliary input is The auxiliary input opening / closing unit when the inverter outputs an inspection voltage lower than the second voltage, and the second voltage sensor does not detect a voltage based on the inspection voltage. Is normal, when a voltage based on the inspection voltage is detected, a control unit having a function of determining that the auxiliary input opening and closing unit is welded,
Power supply unit equipped with.   2. A noise filter is provided between the self-supporting output terminal and the self-supporting output opening / closing part, and a current sensor is provided for detecting a current flowing between the noise filter and the self-supporting output opening / closing part. The power supply device described in 1. Equipped with an inverter and functioning as a grid connection with the first voltage via the commercial power system via the grid connection switch, and as a self-sustained power with a voltage of 2 lower than the first voltage via the independent output switch In a power supply device having a function of providing an output and a function of accepting an auxiliary input from the outside via an auxiliary input opening / closing unit, a welding determination method performed by a control unit of the power supply device,
The system connection open / close unit, the independent output open / close unit, and the auxiliary input open / close unit are controlled to open, and the auxiliary input is not in a state,
In that state, the inverter is made to output a test voltage that is lower than the second voltage and is not normally used,
When the voltage based on the inspection voltage is not detected between the auxiliary input switching unit and the auxiliary input terminal, the auxiliary input switching unit is normal, and the voltage based on the inspection voltage is detected It is determined that the auxiliary input opening / closing part is welded.
Welding judgment method.

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