JP2017225243A - Electric shock prevention circuit for photovoltaic power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric shock prevention circuit for a photovoltaic power generation system capable of effectively preventing an electric shock accident caused by fire extinction water discharge.SOLUTION: A high voltage pulse current Id is outputted from a pulse generation circuit 12 integrated between a positive electrode side output cable way 2A and a negative electrode side output cable way 2B connecting solar cell modules M1, M2, ..., Mn with an external load 3 in the case of fire occurrence. A Zener diode 9 of a short-circuiting circuit 6 additionally provided in each solar cell module is conducted, and a gate current Ig is caused to flow into a gate of a thyristor 8 for ignition. A short-circuiting cable way 7 connecting a positive electrode terminal P1 and a negative electrode terminal P2 of each solar cell module is conducted for providing a short-circuited state, such that leakage of electricity to the outside is avoided. After the end of a fire extinction activity, when a reset switch 13 is turned on and the positive electrode side output cable way 2A and the negative electrode side output cable way 2B are short-circuited, the thyristor 8 is returned into a non-conducted state, and a photovoltaic power generation system 1 is recovered in a normal operation state.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electric shock prevention circuit for preventing an electric shock accident to a human body due to fire extinguishing water discharge when a fire occurs at a place where a solar power generation system is installed.

  In recent years, solar power generation systems have spread rapidly and are being introduced into many ordinary homes. Under such circumstances, sufficient safety has not been secured in the fire of a house where a photovoltaic power generation system is installed, and in particular, the risk of electric shock in fire fighting activities is hardly taken into consideration.

  FIG. 13 is a schematic circuit diagram showing an example of a conventional general photovoltaic power generation system. The photovoltaic power generation system A1 in FIG. 13 includes n solar cell modules M1 connected in series, It has a three-string structure consisting of M2 ·· Mn.

  The positive electrode side and the negative electrode side of these strings are connected in parallel to an external load (power conditioner) A4 via a positive electrode output circuit A2 and a negative electrode output circuit A3, respectively. In addition, open / close switches Swa and Swb of the DC switch A5 are incorporated in the positive output circuit A2 and the negative output circuit A2 connecting the strings and the external load A4.

  Further, a bypass diode D is incorporated between the positive electrode terminal P1 and the negative electrode terminal P2 of each solar cell module M1, M2,... Mn, and the DC switch Swa and the external load of each positive electrode output circuit A2 A backflow prevention diode A6 is incorporated between A4 and A4.

  In the photovoltaic power generation system shown in the figure, the power generated by the solar cell modules M1, M2,... Mn is supplied to the external load A4 via the DC switch A5 and the backflow prevention diode A6. If a fire breaks out at the place where the photovoltaic power generation system A1 is installed, when water is discharged for extinguishing, even if the open / close switches Swa, Swb of the DC switch A5 are shut off, these solar cell modules M1, M2,. As long as Mn continues to generate electricity, there is a risk of electric shock being transmitted to the human body through water discharge.

  Therefore, as a conventional safety measure at the time of fire fighting, for example, as described in Patent Document 1, the solar battery module string is separated from the power conditioner by the fire detection signal output from the fire detection means. A technique has been proposed in which a short-circuit prevention resistor having a predetermined resistance value is connected between the output terminals of the string and the output voltage is lowered to a safe voltage for the human body.

JP 2014-68509 A

  However, in recent years, since the performance of individual solar cell modules used in the photovoltaic power generation system has been improved and high output ones have been manufactured, there is an increased risk of electric shock from the water discharged to the solar cell modules. ing.

  Accordingly, the present invention provides an electric shock prevention circuit for a solar power generation system that can solve the problems of the conventional solar power generation system as described above and can effectively prevent an electric shock accident due to firefighting and water discharge. Objective.

  The electric shock prevention circuit of the photovoltaic power generation system according to the present invention provided for the above-described purpose is configured such that a plurality of solar cell modules connected in series are connected to an external load via a positive output circuit and a negative output circuit. Which is applied to a photovoltaic power generation system, which is connected to a positive terminal and a negative terminal of each solar cell module, to each of the short circuit, and to a positive terminal of a corresponding solar cell module A thyristor in which an anode is incorporated so that a cathode is connected to a negative terminal, and a gate is connected to the positive terminal via a Zener diode having a Zener voltage higher than an open voltage of the solar cell module; and the positive output A high-voltage pulse that is built in between the electric circuit and the negative output circuit, and exceeds the sum of the Zener voltages of all Zener diodes. By generating a flow, each thyristor is ignited, a pulse generation circuit that conducts each short circuit simultaneously, and a short circuit between the positive output circuit and the negative output circuit to extinguish each thyristor, A reset circuit is provided for returning the short-circuit circuits to the non-conductive state all at once.

  In the electric shock prevention circuit of the photovoltaic power generation system of the present invention, an NTC thermistor or a CTR thermistor that conducts when the surroundings rise to a predetermined temperature and ignites the thyristor between the positive electrode terminal of each solar cell module and the gate of the thyristor. It is desirable to be connected via

  In the electric shock prevention circuit of the photovoltaic power generation system of the present invention, one end of the pulse generation circuit and the reset circuit is connected to the positive output circuit directly or via the positive common circuit, and the other end is the negative electrode. A first charge / discharge circuit connected directly to the side output circuit or via the negative side common circuit, and one end connected to the positive side output circuit directly or via the positive side common circuit, and the other end Is connected to the negative-side output circuit directly or via the negative-side common circuit, a first switching element incorporated in the first charging / discharging path, and a second charging / discharging circuit A second switch element incorporated in the path, a first charge / discharge path, a first capacitor incorporated closer to the positive output circuit than the first switch element, and a second charge / discharge path, From the second switch element to the negative side output circuit A second capacitor, a first switch element and a first capacitor in the first charge / discharge path, and a second switch element and a second capacitor in the second charge / discharge path. It is also desirable that the circuit unit is integrally formed as a circuit unit including a bypass electric circuit that communicates with each other and a third switch element incorporated in the bypass electric circuit.

  According to the first aspect of the present invention, when a fire occurs at the place where the photovoltaic power generation system is installed, each solar cell module can be individually short-circuited to avoid leakage to the outside. Water discharge work during firefighting activities can be performed safely.

  In addition, since the operation of switching to the short circuit state and returning from the short circuit state of each solar cell module can be performed simultaneously from the pulse generation circuit and the reset circuit incorporated between the positive output circuit and the negative output circuit. In addition to being able to start fire fighting activities immediately when a fire breaks out, the solar power generation system can be easily returned to normal operation after the fire fighting activities are completed.

  In addition, since the operation of switching to the short-circuit state of each solar cell module and returning from the short-circuit state can be performed from a remote location without adding a signal cable or wireless communication means to the system separately, And high reliability can be obtained, and it can be carried out at a low cost.

  According to the invention described in claim 2, the NTC thermistor or the CTR thermistor provided in each solar cell module detects a temperature rise around the solar cell module, autonomously fires the thyristor, Therefore, even when ignition of the thyristor by the pulse generation circuit becomes impossible due to disconnection or the like due to fire, electric shock due to water discharge to the solar cell module can be avoided.

  According to the invention described in claim 3, since the pulse generation circuit and the reset circuit are integrated using the three switch elements and the two capacitors, the circuit configuration is simple and the three switch elements By the combination of ON / OFF operations, both the ignition and extinguishing operations of the thyristors attached to the respective solar cell modules can be performed.

It is a typical circuit diagram of a photovoltaic power generation system showing one embodiment of an electric shock prevention circuit of the present invention. In the photovoltaic power generation system shown in FIG. 1, it is a figure which shows the state which the pulse generation circuit output the high voltage | pressure pulse current. It is operation | movement explanatory drawing of the short circuit attached to each solar cell module. It is operation | movement explanatory drawing which shows the state which the NTC thermistor of the short circuit attached to each solar cell module conducted. In the photovoltaic power generation system shown in FIG. 1, it is a figure which shows the state which short-circuited between the positive electrode side output circuit and the negative electrode side output circuit by the reset circuit. It is a figure which shows the modification of a short circuit which replaced the thyristor with the equivalent circuit which consists of a PNP type transistor and an NPN type transistor. It is a figure which shows the circuit unit which integrated the pulse generation circuit and the reset circuit in another embodiment of the electric shock prevention circuit of this invention. FIG. 8 is an operation explanatory diagram of the circuit unit shown in FIG. 7, in which FIG. 7A shows a charging process, FIG. 7B shows a high voltage pulse generation process, and FIG. 7C shows a reset (short circuit) state. It is a figure which shows the circuit unit in another embodiment of the electric shock prevention circuit of this invention. It is sectional drawing of the switch switching mechanism in the operation box which incorporated the circuit unit. It is sectional drawing of the switch switching mechanism in the operation box in a charge process. It is sectional drawing of the switch switching mechanism in the operation box at the time of reset. It is a typical circuit diagram which shows an example of the conventional general photovoltaic power generation system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic circuit diagram of a photovoltaic power generation system incorporating the electric shock prevention circuit of the present invention. The photovoltaic power generation system 1 shown in FIG. 1 includes n solar cell modules M1 connected in series. , M2,... Mn in a single string configuration, and the positive electrode side and the negative electrode side of the strings of these solar cell modules M1, M2,. It is connected to an external load 3 such as a power conditioner via an electric circuit 2B.

  As shown in the figure, a DC switch 4 is incorporated in the positive output circuit 2A and the negative output circuit 2B. The DC switch 4 has a pair of on / off switches 4A and 4B for opening and closing the positive output circuit 2A and the negative output circuit 2B, respectively.

  These open / close switches 4A, 4B are configured to perform ON / OFF operations simultaneously in cooperation with each other. Further, a backflow prevention diode 5 is incorporated between the external load 3 and the open / close switch 4A on the positive output circuit 2A side.

  A bypass diode D is connected between the positive terminal P1 and the negative terminal P2 of each of the solar cell modules M1, M2,. In the following, one of these solar cell modules M1, M2,... Mn will be described as a solar cell module Mi.

  Each solar cell module Mi is provided with a short circuit 6. The short circuit 6 includes a short circuit 7, a thyristor 8, a Zener diode 9, a resistance element 10, and an NTC thermistor 11 that connect between the positive terminal P 1 and the negative terminal P 2 of the solar cell module Mi.

  The thyristor 8 is incorporated in the short circuit 7 so that its anode is connected to the positive terminal P1 of the solar cell module Mi and its cathode is connected to the negative terminal P2. Further, the gate is connected to the positive terminal P1 of the solar cell module Mi via the Zener diode 9, and is connected to the negative terminal P2 via the resistance element 10.

  The Zener diode 9 uses a Zener voltage Vz higher than the open circuit voltage Vm of the solar cell module Mi. The gate of the thyristor 8 is further connected to the positive terminal P1 through an NTC (negative temperature coefficient) thermistor 11.

  The NTC thermistor 11 is an element having a characteristic that the resistance value decreases as the temperature rises. When the ambient temperature of the solar cell module Mi becomes high due to a fire, the resistance value decreases and becomes conductive. It becomes a state.

  Further, between the positive output circuit 2A and the negative output circuit 2B, a pulse generation circuit 12 for firing the thyristor 8 of the short circuit 6 of each solar cell module Mi to make the short circuit 7 conductive, and the thyristor A reset circuit is incorporated to extinguish 8 and return the short circuit 7 to a non-conductive state. In the present embodiment, a reset switch 13 is used as the reset circuit.

  The electric shock prevention circuit of the present invention includes a short circuit 6 attached to each of the solar cell modules Mi, a pulse generation circuit 12 incorporated between the positive output circuit 2A and the negative output circuit 2B, and a reset circuit. The reset switch 13 is configured. The short circuit 6 is preferably mounted in the casing when the solar cell module Mi is manufactured, but may be configured as a unit externally attached to the outside of the casing of the ready-made solar cell module.

  Next, the operation of the electric shock prevention circuit of the present invention configured as described above will be described. FIG. 1 shows a normal operation state of the photovoltaic power generation system 1. In this state, the reset switch 13 is OFF, the open / close switches 4A and 4B of the DC switch 4 are both ON, and the output current I of the solar cell modules M1, M2,. Have been supplied.

  On the other hand, in the event of a fire at the place where the photovoltaic power generation system 1 is installed, the two open / close switches 4A and 4B of the DC switch 4 are turned off as shown in FIG. Thus, the current supplied from these solar cell modules M1, M2,... Mn to the external load 3 is cut off.

  Next, a high voltage pulse current Id is generated by the pulse generation circuit 12 and supplied to each short circuit 6. The output voltage (pulse voltage) Vp of the pulse generation circuit 12 is set higher than n times the zener voltage Vz of each zener diode 9.

  As a result, each zener diode 9 becomes conductive, and as shown in FIG. 3, the gate current Ig that has passed through the zener diode 9 flows into the gate of the thyristor 8 and is fired. A conductive state is established between the cathodes.

  Then, since the current output from the positive terminal P1 of each solar cell module Mi flows to the negative terminal P2 through the short circuit 7 as the short circuit current is, leakage from the solar cell module Mi due to water discharge to the outside is avoided. Can prevent electric shock accidents.

  Further, in the present embodiment, when the ignition of the thyristor 8 of the short circuit 6 of the solar cell module Mi becomes impossible from the pulse generation circuit 12 due to disconnection or the like due to fire, the surroundings of the solar cell module Mi due to the occurrence of fire As shown in FIG. 4, the NTC thermistor 11 becomes conductive, and the gate current Ig flows from the positive terminal P1 side of the solar cell module Mi to the gate of the thyristor 8 via the NTC thermistor 11. Supplied.

  Therefore, separately from the operation of the pulse generation circuit 12, the short circuit 6 attached to each solar cell module Mi can autonomously switch the thyristor 8 to the conductive state. Instead of the NTC thermistor 11, a CTR (critical temperature resistor) thermistor having a characteristic that the resistance value decreases rapidly when a predetermined temperature is exceeded may be used.

  When it is confirmed that there is no abnormality such as damage in the solar power generation system 1 after the fire fighting operation is completed, when returning this to a normal operation state, as shown in FIG. The open / close switches 4A and 4B are switched ON, and the reset switch 13 is switched ON.

  Then, the positive electrode side and the negative electrode side of the string formed of the solar cell modules M1, M2,... Mn connected in series are short-circuited by the reset switch 13. As a result, the current output through each solar cell module Mi circulates as the short-circuit current Is passing through the reset switch 13, and the short-circuit current is flowing through each short-circuit circuit 7 shown in FIG. The arc is extinguished and becomes non-conductive.

  When the reset switch 13 is switched off again from this state as shown in FIG. 1, the power generation outputs of these solar cell modules M1, M2,... Mn are supplied to the external load 3, and the solar power generation system 1 Return to normal operation.

  Since these solar cell modules M1, M2,... Mn do not generate electricity at night, the thyristor 8 is in a non-conductive state at night without performing the ON / OFF switching operation of the reset switch 13. The next morning, the photovoltaic power generation system 1 can be operated normally.

  Next, FIG. 6 shows a modification of the short circuit 6. The short circuit 6 ′ shown in FIG. 6 is a combination of the thyristor 8 of the short circuit 6 described above and a PNP transistor 8 A and an NPN transistor 8 B. In this case, the term “thyristor” described in the claims includes such an equivalent circuit.

  Next, FIG. 7 is a diagram showing a circuit unit in which a pulse generation circuit and a reset circuit are integrated, which is used in another embodiment of the present invention. In this embodiment, the circuit unit other than the circuit unit 14 shown in FIG. This part has the same configuration as that used in the above-described embodiment.

  The circuit unit 14 shown in FIG. 7 has one end connected to the positive output circuit 2A via the positive common circuit 15A and the other end connected to the negative output circuit 2B via the negative common circuit 15B. In addition, the charging / discharging path 16A (first charging / discharging path) and the charging / discharging path 16B (second charging / discharging path) are provided in parallel.

  In the one charging / discharging path 16A, a switching element 17A (first switching element) and a capacitor 18A (first capacitor) are incorporated in series by disposing the switching element 17A closer to the negative common circuit 15B. Yes.

  The other charge / discharge path 16B includes a switch element 17B (second switch element) and a capacitor 18B (second capacitor) that are incorporated in series with the switch element 17B disposed closer to the positive common circuit 15A. ing.

  Further, the position between the switch element 17A and the capacitor 18A in the charge / discharge path 16A and the position between the switch element 17B and the capacitor 18B in the charge / discharge path 16B are in the middle of the switch element 17C (third switch element). ) Is connected by a bypass electric circuit 19 incorporated therein.

  As shown in FIG. 8A, the circuit unit 14 configured as described above is common to the positive output side from the positive output circuit 2A when the switch elements 17A and 17B are turned ON and the switch element 17C is turned OFF. The charging current Ic flows into the electric path 15A, and the capacitor 18A and the capacitor 18B are charged through the charging / discharging path 16A and the charging / discharging path 16B, respectively.

  Next, as shown in FIG. 8B, when the switch element 17A and the switch element 17B are switched OFF and the switch element 17C is switched ON, the capacitor 18A and the capacitor 18B are connected in series and A high-voltage pulsed discharge current Id obtained by boosting the total open circuit voltage (nVm) of the battery module Mi approximately twice is output.

  Further, as shown in FIG. 8C, when all the switch elements 17A, 17B, and 17C are turned on, the positive-side output circuit 2A to the positive-side common circuit 15A, the charge / discharge path 16B, the bypass circuit 19, The short circuit current Is flows to the negative output circuit 2B via the discharge circuit 16A and the negative common circuit 15B, and the current passing through each thyristor 8 of the short circuit 7 of each solar cell module Mi disappears. Therefore, these thyristors 8 are reset to a non-conductive state.

  The circuit unit 14 shown in FIG. 7 and FIG. 8 described above charges the capacitor 18A and the capacitor 18B with a voltage nVm that is the sum of the voltages Vm generated by the solar cell modules Mi in a parallel connection state, and then the capacitors 18A, 18A, By switching 18B to the serial connection state, a voltage 2nVm that is twice that voltage is output as the pulse voltage Vp.

  Therefore, in a system with a large number n of series connection of the solar cell modules Mi, the pulse voltage Vp output from the circuit unit 14 becomes excessively high, so that other circuits in the system may be adversely affected.

  Therefore, in such a system, a zener voltage lower than the pulse voltage Vp is provided between the positive common circuit 15A and the negative common circuit 15B of the circuit unit 14 described above, as in the circuit unit 14 ′ shown in FIG. It is desirable to connect the voltage adjusting Zener diode 20 and adjust the pulse voltage Vp output to the outside to an appropriate voltage.

  The voltage adjusting Zener diode 20 may be connected across the positive output circuit 2A and the negative output circuit 2B. In addition, as described above, the circuit units 14 and 14 'in which the pulse generation circuit and the reset circuit are integrated are connected to each other when the external load 3 and the strings of the solar cell modules M1. It may be distributed in a plurality of locations such as near the junction box or near the power conditioner so that the thyristor 8 of each short circuit 6 can be remotely controlled to be remotely controlled.

  Next, FIG. 10 is a sectional view of the switch switching mechanism in the operation box incorporating the circuit unit 14 shown in FIG. 7 or the circuit unit 14 ′ including the voltage adjusting Zener diode 20 shown in FIG. The operation box 21 shown in the figure is for manually switching the switching elements 17A, 17B, and 17C of the circuit units 14 and 14 ′.

  As shown in FIG. 10, an operation panel 23 having a pair of operation button receiving holes 23 a and 23 b is attached to the upper surface of the housing 22 of the operation box 21. A push button 24 and a push button 25 are arranged in the operation button receiving holes 23a and 23b, respectively, and a switch operation rod 26 is integrally provided below the one push button 24. ing.

  The switch operating rod 26 includes a receiving hole 22a that is concentrically opened with the button housing hole 23a in the top wall of the housing 22 and a receiving member 27 that is fixed to the lower portion of the housing 22. It is guided and supported by the hole 27a so as to be slidable in the vertical direction.

  Further, a stopper ring 28 is fitted to the lower end portion of the switch operating rod 26 so as to contact the lower surface of the receiving tool 27 and restrict the upper limit of movement of the switch operating rod 26. Further, on the side surface of the switch operating rod 26, three protrusions 26A, 26B, and 26C are provided in series in the longitudinal direction in order from the bottom.

  A switch operating rod 29 is provided below the other push button 25 integrally therewith. The switch operating rod 29 is formed in a receiving hole 22 b formed concentrically with the button receiving hole 23 b in the top wall portion of the housing 22 and a receiving tool 30 fixed to the upper part in the housing 22. It is supported by the receiving hole 30a so as to be slidable in the vertical direction.

  A retaining ring 31 that abuts the lower surface of the receiving tool 30 and restricts the upper limit of movement of the switch operating rod 29 is fitted to the lower end of the switch operating rod 29. Further, the lower end surface of the switch operating rod 29 is in contact with a contact portion 33a of a swing link 33 that is swingably supported by a shaft 32 on the housing 22 side.

  One end of a tension coil spring 34 is connected to the swing link 33. Further, the other end of the tension coil spring 34 is connected to an intermediate protrusion 26B of the switch operating rod 26 in a state where the tension coil spring 34 is slightly elastically extended.

  Therefore, the switch operating rod 26 is always urged upward by the elastic restoring force of the tension coil spring 34, and the upper end portion of the push button 24 is held at a position protruding a predetermined amount from the upper surface of the operation panel 23. .

  Further, the swing link 33 receives a counterclockwise moment about the shaft 32 from the tension coil spring 34, and as a result, the lower end surface of the switch operating rod 29 is in contact with the swing link 33. Since the portion 33a is always urged upward, the upper end portion of the other push button 25 is also held at a position protruding a predetermined amount from the upper surface of the operation panel 23.

  Inside the housing 22, the above-described three switch elements 17A, 17B, and 17C are arranged in the vertical direction. In the present embodiment, a normally open switch having a swinging actuator having a roller rotatably attached to the tip is used for the switch elements 17A, 17B, and 17C.

  The switch element 17C arranged at the upper part in the housing 22 is mounted upside down with the two lower switch elements 17A, 17B. In the state shown in FIG. 10, the two switch elements 17A, Although both 17B are OFF, the switch element 17C is ON because its actuator is pushed up on the upper surface of the projection 26C. This state is a state in which the positive output circuit 2A and the negative output circuit 2B are connected by capacitors 18A and 18B connected in series.

  Next, as shown in FIG. 11, when one of the push buttons 24 is pressed, the switch operating rod 26 is also displaced downward against the elastic restoring force of the tension coil spring 34. At this time, the projection 26A Due to the lower surface of the protrusion 26B, the switch element 17A and the switch element 17B are turned on when the respective actuators are pushed down.

  At the same time, the projection 26C is displaced downward, so that the switch element 17C is switched off. This state corresponds to FIG. 8 (a). At this time, the two capacitors 18A and 18B shown in FIG. 8 are connected in parallel between the positive output circuit 2A and the negative output circuit 2B. Thus, the battery is charged by the charging current Ic.

  When the finger is released from the push button 24, the switch operating rod 26 returns to the position shown in FIG. 10 due to the elastic restoring force of the tension coil spring 34. At this time, the two capacitors 18A and 18B As shown in b), since the state is switched to the series connection, a high-voltage pulsed current Id is discharged from these capacitors 18A and 18B.

  Also, as shown in FIG. 12, when the push button 24 and the two push buttons 25 are pressed simultaneously, the switch operating rod 26 is displaced downward as in the case of FIG. The switch elements 17A and 17B are both ON.

  At this time, the protrusion 26C disposed on the upper portion of the switch operating rod 26 is displaced downward as in FIG. 11, but when the push button 25 is pressed and the switch operating rod 29 is lowered, the lower end surface thereof. Pushes down the contact portion 33 a of the swing link 33.

  As a result, the swing link 33 rotates clockwise around the shaft 32 against the elastic restoring force of the tension coil spring 34, and the opposite contact portion 33b protrudes from the upper surface of the projection 26C. The actuator of the switch element 17C is pushed up to switch the switch element 17C to ON.

  Then, since these three switching elements 17A, 17B, and 17C conduct in series and pass the short-circuit current Is as shown in FIG. 8C, each thyristor 8 described above becomes non-conducting, and sunlight The power generation system 1 returns to a normal operating state.

  In the embodiment described above, the energy necessary for generating the high voltage pulse of the pulse generation circuit is obtained from the power generation output of the solar cell module, but the power source of the pulse generation circuit may be a separate power source. Furthermore, you may comprise so that operation | movement of a DC switch and a pulse generation circuit may be automatically performed in cooperation with a ground fault detection means built in a fire alarm or a power conditioner.

  The present invention can be effectively used to prevent fire crews from electric shock during fire extinguishing water discharge in the event of a fire at a place where a solar power generation system is installed, and repairs a failed or aged solar cell module It can also be used to protect workers from electric shock accidents during replacement work.

DESCRIPTION OF SYMBOLS 1 Photovoltaic power generation system 2A Positive side output circuit 2B Negative side output circuit 3 External load 4 DC switch 4A, 4B Open / close switch 5 Backflow prevention diode 6, 6 'Short circuit 7 Short circuit 8 Thyristor 8A PNP type transistor 8B NPN type transistor 9 Zener diode 10 Resistance element 11 NTC thermistor 12 Pulse generation circuit 13 Reset switch (reset circuit)
14, 14 Circuit unit 15A Positive side common circuit 15B Negative side common circuit 16A Charge / discharge path (first charge / discharge path)
16B charge / discharge path (second charge / discharge path)
17A switch element (first switch element)
17B switch element (second switch element)
17C switch element (third switch element)
18A capacitor (first capacitor)
18B capacitor (second capacitor)
19 Bypass circuit 20 Voltage adjusting Zener diode 21 Operation box 22 Housing 22a, 22b Receiving hole 23 Operation panel 23a, 23b Push button receiving hole 24, 25 Push button 26 Switch operation rod 27 Receiving tool 27a Receiving hole 28 Retaining ring 29 Switch Operation rod 30 Receiving tool 30a Receiving hole 31 Retaining ring 32 Shaft 33 Swing link 33a, 33b Abutting portion 34 Tension coil spring D Bypass diode I Output current Ic Charging current Id Pulse current Ig Gate current Is Short circuit current is Short circuit current M1, M2, Mi, Mn Solar cell module P1 Positive terminal P2 Negative terminal

Claims (3)

A plurality of solar cell modules connected in series is an electric shock prevention circuit of a solar power generation system connected to an external load through a positive output circuit and a negative output circuit,
A short circuit that connects between the positive terminal and the negative terminal of each solar cell module;
In each of the short-circuit circuits, an anode is connected to the positive terminal of the corresponding solar cell module and a cathode is connected to the negative terminal, and the gate is connected via a Zener diode having a Zener voltage higher than the open circuit voltage of the solar cell module. A thyristor connected to the positive terminal,
Built in between the positive-side output circuit and the negative-side output circuit, and generates a high-voltage pulse current that exceeds the sum of the Zener voltages of all Zener diodes, each thyristor is ignited, and each short-circuit circuit is connected simultaneously. A pulse generation circuit for conducting to,
A photovoltaic power generation system comprising: a reset circuit that short-circuits between the positive-side output circuit and the negative-side output circuit to extinguish each thyristor, and simultaneously returns the short-circuit circuits to a non-conducting state. Electric shock prevention circuit.   The positive electrode terminal of each solar cell module and the gate of the thyristor are connected via an NTC thermistor or a CTR thermistor that conducts when the surroundings rise to a predetermined temperature and ignites the thyristor. The electric shock prevention circuit of the solar power generation system of 1. The pulse generator and reset circuit are
A first charge / discharge circuit having one end connected directly to the positive output circuit or via the positive common circuit, and the other end connected directly or via the negative common circuit to the negative output circuit;
A second charging circuit having one end connected directly to the positive output circuit or via the positive common circuit and the other end connected directly or via the negative common circuit to the negative output circuit. A discharge path;
A first switch element incorporated in the first charge / discharge path;
A second switch element incorporated in the second charge / discharge path;
A first capacitor incorporated in the first charge / discharge path closer to the positive output circuit than the first switch element;
A second capacitor incorporated in the second charge / discharge path closer to the negative output circuit than the second switch element;
A bypass circuit that communicates between the first switch element of the first charge / discharge path and the first capacitor, and between the second switch element of the second charge / discharge path and the second capacitor;
3. The electric shock prevention circuit for a photovoltaic power generation system according to claim 1, wherein the electric shock prevention circuit is integrally formed as a circuit unit including a third switch element incorporated in the bypass electric circuit.

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